metricas
covid
Buscar en
Annals of Hepatology
Toda la web
Inicio Annals of Hepatology The histone variant H3.3 regulates the transcription of the hepatitis B virus
Journal Information

Statistics

Follow this link to access the full text of the article

Original article
The histone variant H3.3 regulates the transcription of the hepatitis B virus
Francisca Alvarez-Astudilloa,1, Daniel Garridoa, Manuel Varas-Godoyb, José Leonardo Gutiérrezc, Rodrigo A. Villanuevaa,**, Alejandra Loyolaa,d,
a Fundación Ciencia & Vida, Avenida Zañartu 1482, Ñuñoa, 7780272, Santiago, Chile
b Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad, San Sebastián, Santiago, 7510157, Chile
c Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción, 4070043, Chile
d Universidad San Sebastián, Santiago, 7510157, Chile
Read
2368
Times
was read the article
556
Total PDF
1812
Total HTML
Share statistics
 array:24 [
  "pii" => "S1665268120301769"
  "issn" => "16652681"
  "doi" => "10.1016/j.aohep.2020.09.005"
  "estado" => "S300"
  "fechaPublicacion" => "2021-03-01"
  "aid" => "261"
  "copyright" => "AEDV"
  "copyrightAnyo" => "2020"
  "documento" => "article"
  "crossmark" => 1
  "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
  "subdocumento" => "fla"
  "cita" => "Ann Hepatol. 2021;21C:"
  "abierto" => array:3 [
    "ES" => true
    "ES2" => true
    "LATM" => true
  ]
  "gratuito" => true
  "lecturas" => array:1 [
    "total" => 0
  ]
  "itemSiguiente" => array:19 [
    "pii" => "S1665268120301757"
    "issn" => "16652681"
    "doi" => "10.1016/j.aohep.2020.09.004"
    "estado" => "S300"
    "fechaPublicacion" => "2021-03-01"
    "aid" => "260"
    "copyright" => "AEDV"
    "documento" => "article"
    "crossmark" => 1
    "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
    "subdocumento" => "fla"
    "cita" => "Ann Hepatol. 2021;21C:"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:1 [
      "total" => 0
    ]
    "en" => array:11 [
      "idiomaDefecto" => true
      "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>"
      "titulo" => "Outcomes of Japanese patients with non-alcoholic fatty liver disease according to genetic background and lifestyle-related diseases"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => "en"
      "contieneResumen" => array:1 [
        "en" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:8 [
          "identificador" => "fig0015"
          "etiqueta" => "Fig&#46; 3"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr3.jpeg"
              "Alto" => 4296
              "Ancho" => 2413
              "Tamanyo" => 460031
            ]
          ]
          "detalles" => array:1 [
            0 => array:3 [
              "identificador" => "at0015"
              "detalle" => "Fig&#46; "
              "rol" => "short"
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Survival rates of ALDH2 SNPs in the complications of lifestyle-related disease subgroups&#46;</p> <p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">Survival rates were evaluated by Kaplan&#8211;Meier analysis in the &#40;a&#41; BMI&#8239;&#60;&#8239;25&#8239;kg&#47;m<span class="elsevierStyleSup">2</span>&#44; &#40;b&#41; BMI&#8239;&#8805;&#8239;25&#8239;kg&#47;m<span class="elsevierStyleSup">2</span>&#44; &#40;c&#41; non-diabetes&#44; &#40;d&#41; diabetes&#44; &#40;e&#41; non-dyslipidemia&#44; &#40;f&#41; dyslipidemia&#44; &#40;g&#41; non-hypertension&#44; and &#40;h&#41; hypertension subgroups&#46;</p> <p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">The survival rate did not differ significantly among patients with obesity &#40;BMI&#8239;&#60;&#8239;25&#8239;kg&#47;m<span class="elsevierStyleSup">2</span>&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;17&#44; a&#59; BMI&#8239;&#8805;&#8239;25&#8239;kg&#47;m<span class="elsevierStyleSup">2</span>&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;12&#44; b&#41; and diabetes &#40;non- diabetes&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;17&#44; c&#59; diabetes&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239; 0&#46;25&#44; d&#41;&#46; The survival rate of the non-GG genotype of ALDH2 was significantly lower in patients without dyslipidemia and with hypertension &#40;non-dyslipidemia <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;01&#44; e&#59; hypertension <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;03&#44; h&#41;&#46; The relationship was not statistically significant in patients with dyslipidemia or without hypertension &#40;dyslipidemia&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;76&#44; f&#59; non-hypertension&#58; <span class="elsevierStyleItalic">p</span>&#8239;&#61;&#8239;0&#46;89&#44; g&#41;&#46;</p> <p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">ALDH2&#44; aldehyde dehydrogenase 2&#59; SNP&#44; single nucleotide polymorphism&#59; BMI&#44; body mass index DM&#44; diabetes mellitus&#59; DL&#44; dyslipidemia&#59; HT&#44; hypertension&#46;</p>"
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "Tomomi Kogiso, Takaomi Sagawa, Kazuhisa Kodama, Makiko Taniai, Etsuko Hashimoto, Katsutoshi Tokushige"
          "autores" => array:6 [
            0 => array:2 [
              "nombre" => "Tomomi"
              "apellidos" => "Kogiso"
            ]
            1 => array:2 [
              "nombre" => "Takaomi"
              "apellidos" => "Sagawa"
            ]
            2 => array:2 [
              "nombre" => "Kazuhisa"
              "apellidos" => "Kodama"
            ]
            3 => array:2 [
              "nombre" => "Makiko"
              "apellidos" => "Taniai"
            ]
            4 => array:2 [
              "nombre" => "Etsuko"
              "apellidos" => "Hashimoto"
            ]
            5 => array:2 [
              "nombre" => "Katsutoshi"
              "apellidos" => "Tokushige"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1665268120301757?idApp=UINPBA00004N"
    "url" => "/16652681/000000210000000C/v1_202102250957/S1665268120301757/v1_202102250957/en/main.assets"
  ]
  "itemAnterior" => array:19 [
    "pii" => "S1665268120301800"
    "issn" => "16652681"
    "doi" => "10.1016/j.aohep.2020.09.009"
    "estado" => "S300"
    "fechaPublicacion" => "2021-03-01"
    "aid" => "265"
    "copyright" => "AEDV"
    "documento" => "article"
    "crossmark" => 1
    "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
    "subdocumento" => "fla"
    "cita" => "Ann Hepatol. 2021;21C:"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:1 [
      "total" => 0
    ]
    "en" => array:11 [
      "idiomaDefecto" => true
      "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>"
      "titulo" => "Alterations in chemokine receptor CCR5 activity influence tumor cell biology in human cholangiocarcinoma cell lines"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => "en"
      "contieneResumen" => array:1 [
        "en" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:7 [
          "identificador" => "fig0005"
          "etiqueta" => "Fig&#46; 1"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr1.jpeg"
              "Alto" => 910
              "Ancho" => 1508
              "Tamanyo" => 94521
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">CCR subtype mRNA expression in HuCCT1 and KMBC cells as determined by real-time RT-PCR&#46; Human activated peripheral blood mononuclear cells &#40;PBMCs&#41; served as positive controls&#46; Data presented as mean<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>SD of three determinations&#46;</p>"
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "Jiaqi Yang, David Sontag, Yuewen Gong, Gerald Y&#46; Minuk"
          "autores" => array:4 [
            0 => array:2 [
              "nombre" => "Jiaqi"
              "apellidos" => "Yang"
            ]
            1 => array:2 [
              "nombre" => "David"
              "apellidos" => "Sontag"
            ]
            2 => array:2 [
              "nombre" => "Yuewen"
              "apellidos" => "Gong"
            ]
            3 => array:2 [
              "nombre" => "Gerald Y&#46;"
              "apellidos" => "Minuk"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1665268120301800?idApp=UINPBA00004N"
    "url" => "/16652681/000000210000000C/v1_202102250957/S1665268120301800/v1_202102250957/en/main.assets"
  ]
  "en" => array:19 [
    "idiomaDefecto" => true
    "cabecera" => "<span class="elsevierStyleTextfn">Original article</span>"
    "titulo" => "The histone variant H3&#46;3 regulates the transcription of the hepatitis B virus"
    "tieneTextoCompleto" => true
    "autores" => array:1 [
      0 => array:3 [
        "autoresLista" => "Francisca Alvarez-Astudillo, Daniel Garrido, Manuel Varas-Godoy, Jos&#233; Leonardo Guti&#233;rrez, Rodrigo A&#46; Villanueva, Alejandra Loyola"
        "autores" => array:6 [
          0 => array:3 [
            "nombre" => "Francisca"
            "apellidos" => "Alvarez-Astudillo"
            "referencia" => array:2 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
              1 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">1</span>"
                "identificador" => "fn0005"
              ]
            ]
          ]
          1 => array:3 [
            "nombre" => "Daniel"
            "apellidos" => "Garrido"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
            ]
          ]
          2 => array:3 [
            "nombre" => "Manuel"
            "apellidos" => "Varas-Godoy"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">b</span>"
                "identificador" => "aff0010"
              ]
            ]
          ]
          3 => array:3 [
            "nombre" => "Jos&#233; Leonardo"
            "apellidos" => "Guti&#233;rrez"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">c</span>"
                "identificador" => "aff0015"
              ]
            ]
          ]
          4 => array:4 [
            "nombre" => "Rodrigo A&#46;"
            "apellidos" => "Villanueva"
            "email" => array:1 [
              0 => "rvillanueva@cienciavida.org"
            ]
            "referencia" => array:2 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
              1 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">&#42;&#42;</span>"
                "identificador" => "cor0010"
              ]
            ]
          ]
          5 => array:4 [
            "nombre" => "Alejandra"
            "apellidos" => "Loyola"
            "email" => array:1 [
              0 => "aloyola@cienciavida.org"
            ]
            "referencia" => array:3 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
              1 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">d</span>"
                "identificador" => "aff0020"
              ]
              2 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">&#42;</span>"
                "identificador" => "cor0005"
              ]
            ]
          ]
        ]
        "afiliaciones" => array:4 [
          0 => array:3 [
            "entidad" => "Fundaci&#243;n Ciencia &#38; Vida&#44; Avenida Za&#241;artu 1482&#44; &#209;u&#241;oa&#44; 7780272&#44; Santiago&#44; Chile"
            "etiqueta" => "a"
            "identificador" => "aff0005"
          ]
          1 => array:3 [
            "entidad" => "Centro de Biolog&#237;a Celular y Biomedicina &#40;CEBICEM&#41;&#44; Facultad de Medicina y Ciencia&#44; Universidad&#44; San Sebasti&#225;n&#44; Santiago&#44; 7510157&#44; Chile"
            "etiqueta" => "b"
            "identificador" => "aff0010"
          ]
          2 => array:3 [
            "entidad" => "Departamento de Bioqu&#237;mica y Biolog&#237;a Molecular&#44; Facultad de Ciencias Biol&#243;gicas&#44; Universidad de Concepci&#243;n&#44; Barrio Universitario s&#47;n&#44; Concepci&#243;n&#44; 4070043&#44; Chile"
            "etiqueta" => "c"
            "identificador" => "aff0015"
          ]
          3 => array:3 [
            "entidad" => "Universidad San Sebasti&#225;n&#44; Santiago&#44; 7510157&#44; Chile"
            "etiqueta" => "d"
            "identificador" => "aff0020"
          ]
        ]
      ]
    ]
    "resumenGrafico" => array:2 [
      "original" => 0
      "multimedia" => array:8 [
        "identificador" => "fig0010"
        "etiqueta" => "Fig&#46; 2"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr2.jpeg"
            "Alto" => 1758
            "Ancho" => 2925
            "Tamanyo" => 337828
          ]
        ]
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at0010"
            "detalle" => "Fig&#46; "
            "rol" => "short"
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">The histone variant H3&#46;3 histone is necessary to regulate HBV transcription&#46;</p> <p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">&#40;A&#41; Scheme illustrating the shH3&#46;3 experiment and detection of the HBV viral intermediates&#46; &#40;B&#41; Levels of mRNA on samples derived from shControl or shH3&#46;3 treated Huh7 cells measured by real-time PCR&#46; The graph shows mRNA levels expressed relative to the shControl&#46; Each expression level was normalized to that of GAPDH&#46; The standard deviation was obtained from three independent experiments&#46; &#40;C&#41; Cell cycle profile of Huh7 cells treated with shH3&#46;3&#46; The standard deviation was obtained from three independent experiments&#46; &#40;D&#41; Covalent post-translational modifications on histone H3 were determined by ChIP analysis using the specific antibodies&#58; H3 &#40;left&#41; and H3K4me3 &#40;right&#41;&#46; Immunoprecipitated DNA was quantified by qPCR using specific primers for core promoter&#46; The results are expressed as fold changes of &#37; Input with respect to the control&#46; The standard deviation was obtained from three PCR reactions and the graphs are representative of two independent experiments&#46; &#40;E&#41; The HBV replicative intermediates cytoplasmic viral core particles &#40;cytDNA&#44; right&#41; and cccDNA &#40;left&#41; were determined 72&#8239;h post-transfection of the shH3&#46;3 construct&#46; The value obtained in shControl and in shH3&#46;3 was divided by the shControl value&#44; thus the results are expressed relative to the Control&#46; The standard deviation was obtained from three independent experiments&#46; &#40;F&#41; The quantity of the viral antigen HBsAg in the supernatant of the transfected cells was determined by ELISA&#44; using specific antibodies&#46; The result is shown as fold changes with respect to the control&#46; The standard deviation was obtained from three independent experiments&#46; &#42;&#58; p&#8239;&#60;&#8239;0&#46;05&#44; &#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;01&#44; Student&#8217;s <span class="elsevierStyleItalic">t</span>-test&#46;</p>"
        ]
      ]
    ]
    "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">1</span><span class="elsevierStyleSectionTitle" id="sect0035">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">Infection with the hepatitis B virus &#40;HBV&#41; continues to be a serious worldwide health problem&#44; despite the existence of an effective vaccine&#46; Data from the World Health Organization estimate that more than 250 million people around the world are chronically infected with HBV&#46; Complications of chronic HBV infection include cirrhosis and hepatocellular carcinoma &#91;<a class="elsevierStyleCrossRef" href="#bib0005">1</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0010">2</a>&#93;&#46;</p><p id="par0010" class="elsevierStylePara elsevierViewall">HBV is a small&#44; enveloped DNA virus and a prototypic member of the <span class="elsevierStyleItalic">Hepadnaviridae</span> family&#46; The HBV genome is a partially double-stranded circular DNA molecule of 3&#46;2&#8239;kb&#44; surrounded by the viral capsid&#46; The infection starts with the binding of HBV to its cellular receptor&#44; the NTCP protein that localizes in the hepatocyte surface &#91;<a class="elsevierStyleCrossRef" href="#bib0015">3</a>&#93;&#46; In the nucleus&#44; the viral genome repairs to generate the covalently closed circular DNA &#40;cccDNA&#41; molecule that serves as a template for viral transcription &#91;<a class="elsevierStyleCrossRef" href="#bib0020">4</a>&#93;&#46; The cccDNA organizes as a minichromosome associated with histones and non-histone proteins &#91;<a class="elsevierStyleCrossRef" href="#bib0025">5</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0030">6</a>&#93;&#44; and its transcription depends on the cellular transcriptional machinery&#46; In recent years&#44; many groups have characterized how post-translational modifications on the histones associated with the cccDNA regulate viral transcription &#91;<a class="elsevierStyleCrossRefs" href="#bib0035">7&#8211;16</a>&#93;&#46; Histone acetylation and methylation of the lysine 4 of the histone H3 &#40;H3K4me&#41; correlate with active viral transcription&#44; whereas histone hypoacetylation&#44; H3K9me and H4R3me correlate with viral repression&#46; Consistently&#44; chromatin-modifying enzymes that impose marks on histone proteins are recruited to cccDNA &#91;<a class="elsevierStyleCrossRef" href="#bib0035">7</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0045">9</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0070">14</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0080">16</a>&#93;&#46;</p><p id="par0015" class="elsevierStylePara elsevierViewall">The incorporation of histone variants to chromatin is another way of regulating chromatin function&#46; These are non-canonical &#40;non-allelic&#41; variants of histones&#44; characterized by differences in few amino acids&#44; and expressed at low levels compared to the canonical ones&#46; They have specific expression&#44; localization&#44; and developmental pattern expression &#91;<a class="elsevierStyleCrossRefs" href="#bib0085">17&#8211;19</a>&#93;&#46; The canonical histones H3 are H3&#46;1 and H3&#46;2&#44; which express coupled to the DNA synthesis and incorporated into the chromatin during DNA replication by the histone chaperone CAF1 &#91;<a class="elsevierStyleCrossRef" href="#bib0100">20</a>&#93;&#46; The most common H3 variant is H3&#46;3&#44; differing in only five amino acids compared to H3&#46;1&#46; This variant is expressed all through the cell cycle&#44; and it is assembled into chromatin independently of DNA replication&#46; H3&#46;3 enriches at actively transcribed genes&#44; promoters&#44; and regulatory elements&#44; where it is assembled by the histone chaperone HIRA &#91;<a class="elsevierStyleCrossRef" href="#bib0100">20</a>&#93;&#46; Consistently&#44; histone H3&#46;3 from different species is enriched in post-translational modifications associated with transcriptional activation &#91;<a class="elsevierStyleCrossRefs" href="#bib0105">21&#8211;23</a>&#93;&#46; However&#44; H3&#46;3 also accumulates at pericentric heterochromatin and telomeres &#91;<a class="elsevierStyleCrossRefs" href="#bib0120">24&#8211;27</a>&#93;&#44; and is also required for silencing endogenous retroviral elements in mouse embryonic stem cells &#91;<a class="elsevierStyleCrossRef" href="#bib0140">28</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0145">29</a>&#93;&#46; The histone chaperone Daxx&#47;ATRX assembles H3&#46;3 at these loci &#91;<a class="elsevierStyleCrossRef" href="#bib0140">28</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0145">29</a>&#93;&#46; Therefore&#44; H3&#46;3 is involved in gene transcription and silencing&#46; The diverse H3&#46;3 roles are most likely linked to how it assembles into chromatin at specific genomic regions&#46; Here&#44; we investigated the function of the histone variant H3&#46;3 in the HBV transcription&#46; We found that H3&#46;3 is assembled into the cccDNA by the histone chaperone HIRA and that this assembly correlates with increased levels of the active mark H3K4me and the activation of HBV transcription&#46;</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2</span><span class="elsevierStyleSectionTitle" id="sect0040">Materials and methods</span><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;1</span><span class="elsevierStyleSectionTitle" id="sect0045">Reagents and primers</span><p id="par0020" class="elsevierStylePara elsevierViewall">The following antibodies were used&#58; anti-Flag beads &#40;Sigma Aldrich A2220&#41;&#44; &#946;-actin &#40;Millipore 04-1116&#41;&#44; Flag &#40;Sigma Aldrich F3165-2MG&#41;&#44; histone H3 &#40;Abcam ab1791&#41;&#44; H3K4me3 &#40;Abcam ab8580&#41;&#44; HIRA &#40;Abcam ab20655&#41;&#46; The following plasmids were used&#58; pOZ-H3&#46;3-Flag&#44; pcDNA3-HA-FLAG&#46; The following primers were used&#58; primer cccDNA&#44; amplify the region between 1662&#8211;1923 &#40;261 bp product&#41; of Hepatitis B virus strain F1b&#44; complete genome &#40;GenBank&#58; KM233681&#46;1&#41; &#91;<a class="elsevierStyleCrossRef" href="#bib0150">30</a>&#93;&#44; Forward 5&#8242;-ACT CTT GGA CTT TCA GGA AGG-3&#44; Reverse 5&#8242;-TCT TTA TAA GGG TCA ATG TCC AT-3&#8242;&#59; primer core promoter region&#44; amplify the area between 1677&#8211;1790 &#40;113 bp product&#41; of Hepatitis B virus strain F1b&#44; complete genome &#40;GenBank&#58; KM233681&#46;1&#41; &#91;<a class="elsevierStyleCrossRef" href="#bib0150">30</a>&#93;&#44; Forward 5&#8242;-GGA AGG TCA ATG ACC TGG ATC-3&#8242;&#44; Reverse 5&#8242;-ATG CCT ACA GCC TCC TAA TAC-3&#8242;&#59; primer PreS1 promoter region&#44; amplify the area between 2697&#8211;2801 &#40;104 bp product&#41; of Hepatitis B virus strain F1b&#44; complete genome &#40;GenBank&#58; KM233681&#46;1&#41; &#91;<a class="elsevierStyleCrossRef" href="#bib0150">30</a>&#93;&#44; Forward 5&#8242;-CCC TAT TAT CCT GAT AAC GTG G-3&#8242;&#44; Reverse 5&#8242;-GCT ACG TGT GGA TTC TCT CTT-3&#8242;&#59; primer X promoter region&#44; amplify the area between 1219&#8211;1290 &#40;71 bp product&#41; of Hepatitis B virus strain F1b&#44; complete genome &#40;GenBank&#58; KM233681&#46;1&#41; &#91;<a class="elsevierStyleCrossRef" href="#bib0150">30</a>&#93;&#44; Forward 5&#8242;-ATT GGC CAT CAG CGC ATG CG-3&#8242;&#44; Reverse 5&#8242;-AGC TGC AAG GAG TTC CGC AGT-3&#8242;&#59; primer H3&#8239;F3A&#58; Forward 5&#8242;-GCA AGA GTG CGC CCT CTA CTG-3&#8242;&#44; Reverse 5&#8242;- GGC CTC ACT TGC CTC CTG CAA A-3&#8242;&#59; primer H3&#8239;F3B&#58; Forward 5&#8242;-GTG GCG CTT CGA GAG ATT C-3&#8242;&#44; Reverse 5&#8242;-GCG AGC CAA CTG GAT GTC TT-3&#8242;&#59; primer GAPDH&#58; Forward 5&#8242;-AGA AGG CTG GGG CTC ATT TG-3&#8242;&#44; Reverse 5&#8242;-AGG GGC CAT CCA GAC TCT TC-3&#8242;&#59; primer HIRA&#58; Forward 5&#8242;&#8211;AAG GAG GCC ATG TGT CTG TC-3&#8242;&#44; Reverse 5&#8242;-CCC CAC CAC TGT CAC TTC AT&#8211;3&#8242;&#46;</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;2</span><span class="elsevierStyleSectionTitle" id="sect0050">Cells and cell culture</span><p id="par0025" class="elsevierStylePara elsevierViewall">The Huh-7 human hepatocarcinoma cell line was grown in Dulbecco&#8217;s modified Eagle&#8217;s medium &#40;DMEM&#41;&#44; supplemented with 10&#37; fetal bovine serum &#40;FBS&#41;&#44; 100U&#47;mL penicillin &#40;Hyclone&#41;&#44; 100ug&#47;mL streptomycin&#44; and 2&#8239;mM glutamine&#46; The cells were incubated at 37&#8239;&#176;C and 5&#37; CO<span class="elsevierStyleInf">2</span>&#46; To harvest the cells&#44; they were trypsinized and collected in completed DMEM&#46;</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;3</span><span class="elsevierStyleSectionTitle" id="sect0055">HBV DNA&#44; plasmids&#44; and si&#47;shRNA transfections</span><p id="par0030" class="elsevierStylePara elsevierViewall">Huh7 cells were seeded at a density of 5&#8239;&#215;&#8239;10<span class="elsevierStyleSup">5</span> and transfected after 24&#8239;h&#46; For shRNA treatment&#44; 3&#8239;&#956;g of either pLL3&#46;7 empty vector as control or with the H3&#46;3 target sequence &#91;<a class="elsevierStyleCrossRef" href="#bib0155">31</a>&#93; were transfected using Lipofectamine 2000 48&#8239;h before HBV transfection&#44; according to the manufacturer&#39;s instructions&#46; For H3&#46;3-Flag overexpression&#44; 5&#8239;&#215;&#8239;10<span class="elsevierStyleSup">5</span> Huh7 cells were transfected with Lipofectamine 2000 48&#8239;h before HBV genome transfection&#46; For siRNA treatment&#44; 10&#8239;nM of either control siRNA &#40;Silencer negative control &#35;1 siRNA&#44; Ambion&#44; Life Technologies&#41; or human HIRA siRNA &#40;sc-43836&#44; Santa Cruz Biotechnology&#41; were transfected with Lipofectamine 2000 48&#8239;h before HBV transfection&#46; siRNA products from Santa Cruz Biotechnology consist of three to five 19&#8211;25&#8239;nt siRNAs target-specific designed to knockdown gene expression&#46; Treated or untreated Huh7 cells were transfected with 1&#46;3&#8239;&#181;g of full-length HBV genotype F genome obtained as described previously &#91;<a class="elsevierStyleCrossRef" href="#bib0060">12</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#93;&#44; using Lipofectamine 2000 &#40;Invitrogen&#41;&#46; The transfection efficiency of Huh7 was determined by flow cytometry with BD FACSDIVA&#8482; Software &#40;BD Bioscience&#41;&#46;</p></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;4</span><span class="elsevierStyleSectionTitle" id="sect0060">cDNA analysis</span><p id="par0035" class="elsevierStylePara elsevierViewall">RNA was obtained using the RNeasy&#174; Mini Kit &#40;Qiagen&#41;&#46; cDNA was synthesized using the GoScript&#8482; Reverse Transcriptase System &#40;Promega&#41; and quantified by qPCR&#46; The data obtained were analyzed by the &#916;&#916;Ct method and plotted in Graph Pad Prism 6&#46;</p></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;5</span><span class="elsevierStyleSectionTitle" id="sect0065">Purification and analysis of HBV cytoplasmic intermediates and cccDNA</span><p id="par0040" class="elsevierStylePara elsevierViewall">HBV intermediates were purified as described previously &#91;<a class="elsevierStyleCrossRef" href="#bib0060">12</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#93;&#46; In brief&#44; nucleic acids from 10&#37; of the harvested cells were purified by treating cells for 1&#8239;h with input lysis buffer &#40;10&#8239;mM Tris&#44; 5&#8239;mM EDTA&#44; 0&#44;5&#37; SDS&#41;&#44; then with proteinase K&#44; phenol&#8211;chloroform &#40;1&#58;1&#41; extraction and ethanol precipitation&#46; The rest of the cells were incubated with lysis buffer &#40;10&#8239;mM Tris pH7&#46;5&#44; 50&#8239;mM NaCl&#44; 0&#44;5 &#37; Nonidet P-40&#44; 1&#8239;mM EDTA&#41; and centrifuged at 2400 x g for 10&#8239;min&#46; The supernatant&#44; containing cytoplasmic and viral particles&#44; was treated with DNase I&#44; proteinase K&#44; and DNA purified by phenol-chloroform &#40;1&#58;1&#41; extraction and ethanol precipitation&#46; The pellet&#44; containing the cccDNA&#44; was incubated with lysis buffer &#40;100&#8239;mM NaOH&#44; 6&#37; SDS&#41; for 30&#8239;min&#46; Sodium acetate was added to a final concentration of 600&#8239;mM and centrifuged at 9600&#8239;&#215;&#8239;<span class="elsevierStyleItalic">g</span> for 20&#8239;min&#46; The cccDNA was purified from the supernatant by phenol-chloroform &#40;1&#58;1&#41; extraction and precipitated with ethanol&#46; HBV intermediates were examined by real-time PCR&#46; The values were presented as change folds and plotted with the Graph Pad Prism 6 software&#46;</p></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;6</span><span class="elsevierStyleSectionTitle" id="sect0070">cccDNA chromatin immunoprecipitation assays</span><p id="par0045" class="elsevierStylePara elsevierViewall">The assay was performed as previously described &#91;<a class="elsevierStyleCrossRef" href="#bib0060">12</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#93;&#44; with minor modifications&#46; Precleared samples &#40;2&#8239;&#181;g&#41; were taken as input control for ChIP reactions&#46; KAPA SYBR FAST &#40;KAPA Biosystems&#41; was used to quantify the immunoprecipitated DNA&#44; according to the manufacturer&#39;s instructions&#46; Immunoprecipitated DNA was quantified by creating a line of best fit from a standard curve using serial dilutions of Input DNA&#46; PCR was carried out for 40 cycles with 95&#8239;&#176;C for 10&#8239;s &#40;melting&#41;&#44; 59&#8239;&#176;C for 5&#8239;s &#40;annealing&#41; and 72&#8239;&#176;C for 5&#8239;s &#40;extension&#41;&#46;</p></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">2&#46;7</span><span class="elsevierStyleSectionTitle" id="sect0075">Cell cycle analysis</span><p id="par0050" class="elsevierStylePara elsevierViewall">Treated Huh7 cells were fixed with 70&#37; cold ethanol and stored overnight at &#8722;20&#8239;&#176;C&#46; Cells were then washed with PBS and incubated with RNaseA for 1&#8239;h at 37&#8239;&#176;C&#46; Cells were washed with PBS and DNA stained with propidium iodide&#46; Samples were analyzed by flow cytometry with BD FACSDIVA&#8482; Software &#40;BD Bioscience&#41;&#44; and cell cycle examined with FlowJovX&#46;0&#46;7 &#40;tree Star&#41;&#46;</p></span></span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">3</span><span class="elsevierStyleSectionTitle" id="sect0080">Results</span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">3&#46;1</span><span class="elsevierStyleSectionTitle" id="sect0085">The histone variant H3&#46;3 associates to the cccDNA and activates HBV transcription</span><p id="par0055" class="elsevierStylePara elsevierViewall">We investigated the role of H3&#46;3 on HBV transcription&#46; However&#44; there are no suitable antibodies available to differentiate between H3&#46;1 and H3&#46;3 variants&#46; Therefore&#44; we exogenously expressed Flag-tagged histone H3&#46;3 so we could purify H3&#46;3 by Flag-immunoprecipitation &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>A&#41; &#91;<a class="elsevierStyleCrossRef" href="#bib0110">22</a>&#93;&#46; Overexpression of histones is harmful to the cell&#59; therefore&#44; we expressed the exogenous H3&#46;3 gene under the regulation of a retroviral promoter&#44; allowing a low expression of H3&#46;3&#44; representing about 8&#37; of the endogenous variant &#91;<a class="elsevierStyleCrossRef" href="#bib0110">22</a>&#93;&#46; The transfection efficiency was about 30&#37; &#40;data not shown&#41;&#46; As shown in <a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>B&#44; we detected H3&#46;3 with Flag antibodies&#46; We then examined whether histone H3&#46;3 associated with the cccDNA by Flag-ChIP &#40;Chromatin immunoprecipitation&#41; analysis&#46; We found that the variant H3&#46;3 associates to the three viral promoters analyzed&#58; core&#44; PreS&#44; and HBx &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>C&#41;&#46; We then examined if the association of H3&#46;3 to the cccDNA results in changes in the transcriptional state of the viral cccDNA&#46; We previously showed that the methylation of the lysine 4 of the histone H3 &#40;H3K4me3&#41; correlates with an active cccDNA chromatin state &#91;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#93;&#46; Thus&#44; we performed ChIP analysis and observed that H3K4me3 is enriched in the viral core promoter upon expression of H3&#46;3-Flag compared to control cells &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>D&#44; right&#41;&#46; We also observed reduced levels of the endogenous histone H3 at the viral core promoter upon expression of H3&#46;3-Flag &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>D&#44; left&#41;&#44; consistent with the fact that actively transcribed genes have nucleosome-free promoters &#91;<a class="elsevierStyleCrossRef" href="#bib0160">32</a>&#93;&#46; Besides&#44; we found that both cytoplasmic viral intermediates significantly increased upon expression of H3&#46;3-Flag &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>E&#41;&#46; We found no changes in the cell cycle upon expression of H3&#46;3-Flag &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>F&#41;&#46; We thus concluded that the histone H3&#46;3 associates to the HBV cccDNA and activates HBV transcription&#46;</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia></span><span id="sec0060" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">3&#46;2</span><span class="elsevierStyleSectionTitle" id="sect0090">The histone variant H3&#46;3 is necessary to regulate HBV transcription</span><p id="par0060" class="elsevierStylePara elsevierViewall">We then decided to diminish the levels of the H3&#46;3 variant&#46; As illustrated in <a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>A&#44; we utilized shRNA against H3&#46;3 &#40;shH3&#46;3&#41;&#46; The transfection efficiency was about 50&#37; &#40;data not shown&#41;&#46; Two genes encode histone H3&#46;3&#44; H3&#8239;F3A&#44; and H3&#8239;F3B &#91;<a class="elsevierStyleCrossRef" href="#bib0095">19</a>&#93;&#44; and we reduced the expression of both mRNAs &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>B&#41;&#46; We found no changes in the cell cycle upon treatment with shH3&#46;3 &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>C&#41;&#46; The H3&#46;3 knocked-down correlated with a significant reduction in the H3K4me3 levels&#44; with a concomitant increase in the amount of histone H3 present on the viral core promoter &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>D&#41;&#46; Consistently&#44; upon H3&#46;3 knockdown&#44; both viral intermediates significantly decreased &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>E&#41;&#46; We also examined the HBs viral antigen&#44; used as a marker of acute infection&#44; showing that shH3&#46;3 gave rise to a reduction on the HBs levels &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>F&#41;&#46; Taken together&#44; the data indicate that H3&#46;3 binds to the cccDNA and positively regulates HBV transcription by activating the cccDNA chromatin state&#46;</p><elsevierMultimedia ident="fig0010"></elsevierMultimedia></span><span id="sec0065" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">3&#46;3</span><span class="elsevierStyleSectionTitle" id="sect0095">The histone chaperone HIRA participates in the assembly of the histone H3&#46;3 into the HBV cccDNA</span><p id="par0065" class="elsevierStylePara elsevierViewall">We finally investigated the molecular mechanism by which the H3&#46;3 histone variant associates to the viral HBV cccDNA&#46; Two histone chaperones assemble H3&#46;3 to the cellular chromatin&#58; HIRA and Daxx&#47;ATRX &#91;<a class="elsevierStyleCrossRef" href="#bib0095">19</a>&#93;&#46; We decided to focus on the chaperone HIRA because it is involved in the assembly of H3&#46;3 to euchromatic regions of the DNA &#91;<a class="elsevierStyleCrossRef" href="#bib0100">20</a>&#93;&#46; Upon knocking down HIRA with a commercial siHIRA &#40;<a class="elsevierStyleCrossRef" href="#fig0015">Fig&#46; 3</a>A and B&#41;&#44; we observed a reduction in the amount of H3&#46;3-Flag associated to the viral core promoter &#40;<a class="elsevierStyleCrossRef" href="#fig0015">Fig&#46; 3</a>C&#41;&#44; indicating that HIRA participates in the assembly of H3&#46;3 to the viral cccDNA&#46; We found no changes in the cell cycle upon treatment with siHIRA &#40;<a class="elsevierStyleCrossRef" href="#fig0015">Fig&#46; 3</a>D&#41;&#46; Consistently&#44; in the 24 or 72&#8239;h HIRA knocked-down conditions&#44; both viral intermediates significantly decreased &#40;<a class="elsevierStyleCrossRef" href="#fig0015">Fig&#46; 3</a>E and F&#44; respectively&#41;&#46; Taken together&#44; we conclude that H3&#46;3 is assembled into the HBV cccDNA by the histone chaperone HIRA&#44; one of the steps that contribute to establishing a transcriptionally active cccDNA chromatin state&#46;</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia></span></span><span id="sec0070" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">4</span><span class="elsevierStyleSectionTitle" id="sect0100">Discussion</span><p id="par0070" class="elsevierStylePara elsevierViewall">The HBV cccDNA molecule is the source of persistence in chronically infected HBV patients&#46; Given that therapeutic treatments for chronically infected patients are inefficient&#44; the characterization of the molecular mechanisms by which HBV regulates its transcription is highly relevant&#44; as it can shed light onto new therapeutic targets &#91;<a class="elsevierStyleCrossRef" href="#bib0165">33</a>&#93;&#46; The HBV genome associates with cellular histones and utilizes cellular machineries to regulate its transcription in a chromatin context&#46; Several studies have contributed to the understanding of the molecular mechanisms that regulates HBV transcription in a chromatin context&#44; mainly focusing on histone post-translational modifications and DNA methylation &#91;<a class="elsevierStyleCrossRefs" href="#bib0035">7&#8211;16</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0170">34</a>&#93;&#46;</p><p id="par0075" class="elsevierStylePara elsevierViewall">Much effort has been spent in understanding the role that histone variants have in the regulation of chromatin dynamics&#46; In the viral context&#44; one report showed that the variants H3&#46;1 and H3&#46;3 are incorporated into the human cytomegalovirus &#40;HCMV&#41; chromatin&#44; and this incorporation occurs independently of DNA replication &#91;<a class="elsevierStyleCrossRef" href="#bib0175">35</a>&#93;&#46; Time-course experiments with the herpes virus&#44; on the other hand&#44; have shown that H3&#46;3 is assembled into HSV-1 chromatin before the canonical variant H3&#46;1&#44; which is assembled into the viral chromatin when HSV-1 DNA replicates &#91;<a class="elsevierStyleCrossRef" href="#bib0180">36</a>&#44;<a class="elsevierStyleCrossRef" href="#bib0185">37</a>&#93;&#46; This observation is consistent with the fact that H3&#46;1 is incorporated into the cellular chromatin coupled to DNA replication &#91;<a class="elsevierStyleCrossRef" href="#bib0100">20</a>&#93;&#46; The incorporation of H3&#46;3 to HSV-1 is dependent on the chaperone HIRA &#91;<a class="elsevierStyleCrossRef" href="#bib0180">36</a>&#93;&#46; Further experiments should address whether the differences observed in HSV-1 and HCMV viruses regarding the dependency of DNA replication and the incorporation of H3&#46;1 into the viral chromatin is due to intrinsic viral differences&#46; We showed that the histone variant H3&#46;3 is deposited into the HBV cccDNA by the histone chaperone HIRA&#44; and that this association correlates with increased levels of the active mark H3K4me3 and with the activation of HBV transcription&#46;</p><p id="par0080" class="elsevierStylePara elsevierViewall">In this study&#44; we utilized the HBV Genotype F&#44; not commonly used in research&#46; This genotype is present in Central and South America and our previous studies showed that it is prevalent in Chile &#91;<a class="elsevierStyleCrossRef" href="#bib0190">38</a>&#93;&#46; We also showed that when compared to HBV Genotype A&#44; the most commonly genotype used in research&#44; genotype A replicated more than genotype F and viral transcriptional activities in both genotypes correlated with their cccDNA chromatin state &#91;<a class="elsevierStyleCrossRef" href="#bib0065">13</a>&#93;&#46; Thus&#44; our study extends research into one of the less characterized genotypes of the human hepatitis B virus&#46;</p></span><span id="sec0075" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleLabel">5</span><span class="elsevierStyleSectionTitle" id="sect0105">Conclusions</span><p id="par0085" class="elsevierStylePara elsevierViewall">This study demonstrated that&#44; in addition to histone post-translational modifications and DNA methylation&#44; histone variants&#44; particularly histone H3&#46;3&#44; contribute to regulate <span class="elsevierStyleItalic">in vitro</span> the HBV cccDNA functional state&#46; Further studies are required to confirm the functionality of these machineries in an <span class="elsevierStyleItalic">in vivo</span> model&#44; as well as to investigate how long changes on the HBV chromatin dynamics last&#46; Thus&#44; the characterization of chromatin regulators that play roles in viral chromatin dynamics might reveal new therapeutic targets to develop drugs for the treatment of chronically infected HBV patients&#46;<span class="elsevierStyleDefList"><span class="elsevierStyleSectionTitle" id="sect0110">List of abbreviations</span><span class="elsevierStyleDefTerm">HBV</span><span class="elsevierStyleDefDescription"><p id="par0090" class="elsevierStylePara elsevierViewall">hepatitis B virus</p></span><span class="elsevierStyleDefTerm">cccDNA</span><span class="elsevierStyleDefDescription"><p id="par0095" class="elsevierStylePara elsevierViewall">covalently closed circular DNA</p></span><span class="elsevierStyleDefTerm">NTCP</span><span class="elsevierStyleDefDescription"><p id="par0100" class="elsevierStylePara elsevierViewall">Sodium taurocholate cotransporting polypeptide</p></span><span class="elsevierStyleDefTerm">ChIP</span><span class="elsevierStyleDefDescription"><p id="par0105" class="elsevierStylePara elsevierViewall">chromatin immunoprecipitation</p></span><span class="elsevierStyleDefTerm">HIRA</span><span class="elsevierStyleDefDescription"><p id="par0110" class="elsevierStylePara elsevierViewall">Histone Regulator A</p></span><span class="elsevierStyleDefTerm">HSV-1</span><span class="elsevierStyleDefDescription"><p id="par0115" class="elsevierStylePara elsevierViewall">herpes simplex virus-1</p></span></span></p></span><span id="sec0080" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0115">Ethics approval and consent to participate</span><p id="par0120" class="elsevierStylePara elsevierViewall">Not applicable</p></span><span id="sec0085" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0120">Consent for publication</span><p id="par0125" class="elsevierStylePara elsevierViewall">Not applicable</p></span><span id="sec0090" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0125">Availability of data and materials</span><p id="par0130" class="elsevierStylePara elsevierViewall">The datasets used and&#47;or analyzed during the current study are available from the corresponding author on reasonable request&#46;</p></span><span id="sec0095" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0130">Conflict of interest</span><p id="par0135" class="elsevierStylePara elsevierViewall">The authors have no conflicts of interest to declare&#46;</p></span><span id="sec0100" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0135">Authors&#8217; contributions</span><p id="par0140" class="elsevierStylePara elsevierViewall">FAA&#44; RAV&#44; and AL conceived and designed the experiments&#59; FAA&#44; DG&#44; MVG&#44; JLG&#44; RAV&#44; and AL performed experiments and analyzed data&#59; FAA&#44; RAV and AL wrote the manuscript&#59; and all authors read and approved the final manuscript&#46;</p></span></span>"
    "textoCompletoSecciones" => array:1 [
      "secciones" => array:14 [
        0 => array:3 [
          "identificador" => "xres1471593"
          "titulo" => "Abstract"
          "secciones" => array:4 [
            0 => array:2 [
              "identificador" => "abst0005"
              "titulo" => "Introduction and Objectives"
            ]
            1 => array:2 [
              "identificador" => "abst0010"
              "titulo" => "Materials and methods"
            ]
            2 => array:2 [
              "identificador" => "abst0015"
              "titulo" => "Results"
            ]
            3 => array:2 [
              "identificador" => "abst0020"
              "titulo" => "Conclusions"
            ]
          ]
        ]
        1 => array:2 [
          "identificador" => "xpalclavsec1340223"
          "titulo" => "Keywords"
        ]
        2 => array:2 [
          "identificador" => "sec0005"
          "titulo" => "Introduction"
        ]
        3 => array:3 [
          "identificador" => "sec0010"
          "titulo" => "Materials and methods"
          "secciones" => array:7 [
            0 => array:2 [
              "identificador" => "sec0015"
              "titulo" => "Reagents and primers"
            ]
            1 => array:2 [
              "identificador" => "sec0020"
              "titulo" => "Cells and cell culture"
            ]
            2 => array:2 [
              "identificador" => "sec0025"
              "titulo" => "HBV DNA&#44; plasmids&#44; and si&#47;shRNA transfections"
            ]
            3 => array:2 [
              "identificador" => "sec0030"
              "titulo" => "cDNA analysis"
            ]
            4 => array:2 [
              "identificador" => "sec0035"
              "titulo" => "Purification and analysis of HBV cytoplasmic intermediates and cccDNA"
            ]
            5 => array:2 [
              "identificador" => "sec0040"
              "titulo" => "cccDNA chromatin immunoprecipitation assays"
            ]
            6 => array:2 [
              "identificador" => "sec0045"
              "titulo" => "Cell cycle analysis"
            ]
          ]
        ]
        4 => array:3 [
          "identificador" => "sec0050"
          "titulo" => "Results"
          "secciones" => array:3 [
            0 => array:2 [
              "identificador" => "sec0055"
              "titulo" => "The histone variant H3&#46;3 associates to the cccDNA and activates HBV transcription"
            ]
            1 => array:2 [
              "identificador" => "sec0060"
              "titulo" => "The histone variant H3&#46;3 is necessary to regulate HBV transcription"
            ]
            2 => array:2 [
              "identificador" => "sec0065"
              "titulo" => "The histone chaperone HIRA participates in the assembly of the histone H3&#46;3 into the HBV cccDNA"
            ]
          ]
        ]
        5 => array:2 [
          "identificador" => "sec0070"
          "titulo" => "Discussion"
        ]
        6 => array:2 [
          "identificador" => "sec0075"
          "titulo" => "Conclusions"
        ]
        7 => array:2 [
          "identificador" => "sec0080"
          "titulo" => "Ethics approval and consent to participate"
        ]
        8 => array:2 [
          "identificador" => "sec0085"
          "titulo" => "Consent for publication"
        ]
        9 => array:2 [
          "identificador" => "sec0090"
          "titulo" => "Availability of data and materials"
        ]
        10 => array:2 [
          "identificador" => "sec0095"
          "titulo" => "Conflict of interest"
        ]
        11 => array:2 [
          "identificador" => "sec0100"
          "titulo" => "Authors&#8217; contributions"
        ]
        12 => array:2 [
          "identificador" => "xack515645"
          "titulo" => "Acknowledgements"
        ]
        13 => array:1 [
          "titulo" => "References"
        ]
      ]
    ]
    "pdfFichero" => "main.pdf"
    "tienePdf" => true
    "fechaRecibido" => "2020-08-31"
    "fechaAceptado" => "2020-09-17"
    "PalabrasClave" => array:1 [
      "en" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Keywords"
          "identificador" => "xpalclavsec1340223"
          "palabras" => array:5 [
            0 => "Hepatitis B virus"
            1 => "cccDNA"
            2 => "H3&#46;3"
            3 => "HIRA"
            4 => "Chromatin assembly"
          ]
        ]
      ]
    ]
    "tieneResumen" => true
    "resumen" => array:1 [
      "en" => array:3 [
        "titulo" => "Abstract"
        "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0010">Introduction and Objectives</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">About 250 million people around the world are chronically infected with the hepatitis B virus &#40;HBV&#41;&#46; Those people are at risk of developing hepatocellular carcinoma&#46; The HBV genome is organized as a minichromosome in the infected hepatocyte and is associated with histones and non-histone proteins&#46; In recent years&#44; many groups have investigated the transcriptional regulation of HBV mediated by post-translational modifications on the histones associated with the covalently closed circular DNA &#40;cccDNA&#41;&#46; Our aim is to investigate the role of the histone variant H3&#46;3&#46;</p></span> <span id="abst0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0015">Materials and methods</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">An <span class="elsevierStyleItalic">in vitro</span> HBV replication model system based on the transfection of linear HBV genome monomeric molecules was used&#46; We then either ectopically expressed or reduced the levels of H3&#46;3&#44; and of its histone chaperone HIRA&#46; Viral intermediates were quantified and the level of H3K4me3 using Chromatin immunoprecipitation &#40;ChIP&#41; assay was measured&#46;</p></span> <span id="abst0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0020">Results</span><p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">Histone variant H3&#46;3 ectopically expressed in cells assembles into the viral cccDNA&#44; correlating with increasing levels of the active histone mark H3K4me3 and HBV transcription&#46; The opposite results were found upon diminishing H3&#46;3 levels&#46; Furthermore&#44; the assembly of H3&#46;3 into the cccDNA is dependent on the histone chaperone HIRA&#46; Diminishing HIRA levels causes a reduction in the HBV intermediates&#46;</p></span> <span id="abst0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025">Conclusions</span><p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">Histone variant H3&#46;3 positively regulates HBV transcription&#46; Importantly&#44; the characterization of the viral chromatin dynamics might allow the discovery of new therapeutic targets to develop drugs for the treatment of chronically-infected HBV patients&#46;</p></span>"
        "secciones" => array:4 [
          0 => array:2 [
            "identificador" => "abst0005"
            "titulo" => "Introduction and Objectives"
          ]
          1 => array:2 [
            "identificador" => "abst0010"
            "titulo" => "Materials and methods"
          ]
          2 => array:2 [
            "identificador" => "abst0015"
            "titulo" => "Results"
          ]
          3 => array:2 [
            "identificador" => "abst0020"
            "titulo" => "Conclusions"
          ]
        ]
      ]
    ]
    "NotaPie" => array:1 [
      0 => array:3 [
        "etiqueta" => "1"
        "nota" => "<p class="elsevierStyleNotepara" id="npar0005">Present address&#58; Centro de Biolog&#237;a Celular y Biomedicina &#40;CEBICEM&#41;&#44; Facultad de Medicina y Ciencia&#44; Universidad&#44; San Sebasti&#225;n&#44; Santiago&#44; 7510157&#44; Chile&#46;</p>"
        "identificador" => "fn0005"
      ]
    ]
    "multimedia" => array:3 [
      0 => array:8 [
        "identificador" => "fig0005"
        "etiqueta" => "Fig&#46; 1"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr1.jpeg"
            "Alto" => 2167
            "Ancho" => 2925
            "Tamanyo" => 385801
          ]
        ]
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at0005"
            "detalle" => "Fig&#46; "
            "rol" => "short"
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">The histone variant H3&#46;3 associates to the cccDNA and activates HBV transcription&#46;</p> <p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">&#40;A&#41; Scheme illustrating H3&#46;3-Flag expression and detection of the HBV viral intermediates&#46; &#40;B&#41; Western blot analysis of H3&#46;3-Flag expression&#46; Seventy-two hours after transfection&#44; 15 and 30&#8239;&#181;g of total cell extracts derived from transfection were separated on 10&#37; SDS-PAGE and Western blotted for Flag&#46; On the left&#44; the migration of molecular size markers is shown&#46; &#40;C&#41; H3&#46;3 association to viral promoters was assayed by ChIP analysis&#46; Immunoprecipitated DNA was quantified by qPCR using specific primers for core&#44; PreS and HBx promoters&#46; The results are expressed as &#37; of input&#46; The standard deviation was obtained from three PCR reactions and the graph is representative of three independent experiments&#46; &#40;D&#41; Covalent post-translational modifications on histone H3 were determined by ChIP analysis using the specific antibodies&#58; H3 &#40;left&#41; and H3K4me3 &#40;right&#41;&#46; Immunoprecipitated DNA was quantified by qPCR using specific primers for core promoter&#46; The results are expressed as fold changes of &#37; Input with respect to the control&#46; The standard deviation was obtained from three PCR reactions and the graphs are representative of two independent experiments&#46; &#40;E&#41; The HBV replicative intermediates cytoplasmic viral core particles &#40;cytDNA&#44; right&#41; and cccDNA &#40;left&#41; were determined 72&#8239;h post-transfection of the H3&#46;3-Flag construct&#46; The value obtained in Control and in H3&#46;3-Flag was divided by the Control value&#44; thus the results are expressed relative to the Control&#46; The standard deviation was obtained from four independent experiments&#46; &#40;F&#41; Cell cycle profile of Huh7 cells expressing H3&#46;3-Flag&#46; The standard deviation was obtained from three independent experiments&#46; &#42;&#58; p&#8239;&#60;&#8239;0&#46;05&#44; &#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;01&#44; &#42;&#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;001&#44; Student&#180;s <span class="elsevierStyleItalic">t</span>-test&#46;</p>"
        ]
      ]
      1 => array:8 [
        "identificador" => "fig0010"
        "etiqueta" => "Fig&#46; 2"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr2.jpeg"
            "Alto" => 1758
            "Ancho" => 2925
            "Tamanyo" => 337828
          ]
        ]
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at0010"
            "detalle" => "Fig&#46; "
            "rol" => "short"
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">The histone variant H3&#46;3 histone is necessary to regulate HBV transcription&#46;</p> <p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">&#40;A&#41; Scheme illustrating the shH3&#46;3 experiment and detection of the HBV viral intermediates&#46; &#40;B&#41; Levels of mRNA on samples derived from shControl or shH3&#46;3 treated Huh7 cells measured by real-time PCR&#46; The graph shows mRNA levels expressed relative to the shControl&#46; Each expression level was normalized to that of GAPDH&#46; The standard deviation was obtained from three independent experiments&#46; &#40;C&#41; Cell cycle profile of Huh7 cells treated with shH3&#46;3&#46; The standard deviation was obtained from three independent experiments&#46; &#40;D&#41; Covalent post-translational modifications on histone H3 were determined by ChIP analysis using the specific antibodies&#58; H3 &#40;left&#41; and H3K4me3 &#40;right&#41;&#46; Immunoprecipitated DNA was quantified by qPCR using specific primers for core promoter&#46; The results are expressed as fold changes of &#37; Input with respect to the control&#46; The standard deviation was obtained from three PCR reactions and the graphs are representative of two independent experiments&#46; &#40;E&#41; The HBV replicative intermediates cytoplasmic viral core particles &#40;cytDNA&#44; right&#41; and cccDNA &#40;left&#41; were determined 72&#8239;h post-transfection of the shH3&#46;3 construct&#46; The value obtained in shControl and in shH3&#46;3 was divided by the shControl value&#44; thus the results are expressed relative to the Control&#46; The standard deviation was obtained from three independent experiments&#46; &#40;F&#41; The quantity of the viral antigen HBsAg in the supernatant of the transfected cells was determined by ELISA&#44; using specific antibodies&#46; The result is shown as fold changes with respect to the control&#46; The standard deviation was obtained from three independent experiments&#46; &#42;&#58; p&#8239;&#60;&#8239;0&#46;05&#44; &#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;01&#44; Student&#8217;s <span class="elsevierStyleItalic">t</span>-test&#46;</p>"
        ]
      ]
      2 => array:8 [
        "identificador" => "fig0015"
        "etiqueta" => "Fig&#46; 3"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr3.jpeg"
            "Alto" => 1663
            "Ancho" => 2925
            "Tamanyo" => 323509
          ]
        ]
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at0015"
            "detalle" => "Fig&#46; "
            "rol" => "short"
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">The histone chaperone HIRA assembles the histone H3&#46;3 into the HBV cccDNA&#46;</p> <p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">&#40;A&#41; Scheme illustrating the siHIRA and detection of the HBV viral intermediates&#46; &#40;B&#41; Levels of mRNA &#40;left&#41; and protein &#40;right&#41; on samples derived from siControl and siHIRA treated Huh7 cells&#46; The graph shows mRNA levels expressed relative to the siControl&#46; The expression level was normalized to that of GAPDH&#46; The standard deviation was obtained from three independent experiments&#46; &#40;C&#41; H3&#46;3 association to viral promoters was assayed by ChIP analysis under siControl and siHIRA conditions&#46; Flag-immunoprecipitated DNA was quantified by qPCR using specific primers for core promoter&#46; The results are expressed as fold changes of &#37; Input with respect to the control&#46; The standard deviation was obtained from three PCR reactions and the graph is representative of two independent experiments&#46; &#40;D&#41; Cell cycle profile of Huh7 cells treated with siHIRA&#46; The standard deviation was obtained from three independent experiments&#46; &#40;E&#8211;F&#41; The HBV intermediates cytoplasmic viral core particles &#40;cytDNA&#44; right&#41; and cccDNA &#40;left&#41; were determined 24 &#40;E&#41; and 72 &#40;F&#41; h post-transfection of the siHIRA&#44; as indicated&#46; The value obtained in siControl and in siHIRA was divided by the siControl value&#44; thus the results are expressed relative to the Control&#46; The standard deviation was obtained from three independent experiments&#46; &#42;&#58; p&#8239;&#60;&#8239;0&#46;05&#44; &#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;01&#44; &#42;&#42;&#42;&#58; p&#8239;&#60;&#8239;0&#46;001&#44; Student&#180;s <span class="elsevierStyleItalic">t</span>-test&#46;</p>"
        ]
      ]
    ]
    "bibliografia" => array:2 [
      "titulo" => "References"
      "seccion" => array:1 [
        0 => array:2 [
          "identificador" => "bibs0005"
          "bibliografiaReferencia" => array:38 [
            0 => array:3 [
              "identificador" => "bib0005"
              "etiqueta" => "&#91;1&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Chronic hepatitis B virus infection"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "B&#46;J&#46; McMahon"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.mcna.2013.08.004"
                      "Revista" => array:7 [
                        "tituloSerie" => "Med Clin North Am"
                        "fecha" => "2014"
                        "volumen" => "98"
                        "numero" => "1"
                        "paginaInicial" => "39"
                        "paginaFinal" => "54"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24266913"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            1 => array:3 [
              "identificador" => "bib0010"
              "etiqueta" => "&#91;2&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Medical virology of hepatitis B&#58; how it began and where we are now"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "W&#46;H&#46; Gerlich"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1186/1743-422X-10-239"
                      "Revista" => array:5 [
                        "tituloSerie" => "Virol J"
                        "fecha" => "2013"
                        "volumen" => "10"
                        "paginaInicial" => "239"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23870415"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            2 => array:3 [
              "identificador" => "bib0015"
              "etiqueta" => "&#91;3&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Sodium taurocholate cotransporting polypeptide is a functional receptor for human hepatitis B and D virus"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "H&#46; Yan"
                            1 => "G&#46; Zhong"
                            2 => "G&#46; Xu"
                            3 => "W&#46; He"
                            4 => "Z&#46; Jing"
                            5 => "Z&#46; Gao"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:3 [
                        "tituloSerie" => "Elife"
                        "fecha" => "2012"
                        "volumen" => "1"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            3 => array:3 [
              "identificador" => "bib0020"
              "etiqueta" => "&#91;4&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Molecular biology of hepatitis B virus infection"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "C&#46; Seeger"
                            1 => "W&#46;S&#46; Mason"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.virol.2018.08.001"
                      "Revista" => array:6 [
                        "tituloSerie" => "Virology"
                        "fecha" => "2015"
                        "volumen" => "479&#8211;480"
                        "paginaInicial" => "672"
                        "paginaFinal" => "686"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/30138834"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            4 => array:3 [
              "identificador" => "bib0025"
              "etiqueta" => "&#91;5&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Hepatitis B virus genome is organized into nucleosomes in the nucleus of the infected cell"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "C&#46;T&#46; Bock"
                            1 => "P&#46; Schranz"
                            2 => "C&#46;H&#46; Schroder"
                            3 => "H&#46; Zentgraf"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/BF01703079"
                      "Revista" => array:7 [
                        "tituloSerie" => "Virus Genes"
                        "fecha" => "1994"
                        "volumen" => "8"
                        "numero" => "3"
                        "paginaInicial" => "215"
                        "paginaFinal" => "229"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/7975268"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            5 => array:3 [
              "identificador" => "bib0030"
              "etiqueta" => "&#91;6&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The covalently closed duplex form of the hepadnavirus genome exists in situ as a heterogeneous population of viral minichromosomes"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "J&#46;E&#46; Newbold"
                            1 => "H&#46; Xin"
                            2 => "M&#46; Tencza"
                            3 => "G&#46; Sherman"
                            4 => "J&#46; Dean"
                            5 => "S&#46; Bowden"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1128/JVI.69.6.3350-3357.1995"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Virol"
                        "fecha" => "1995"
                        "volumen" => "69"
                        "numero" => "6"
                        "paginaInicial" => "3350"
                        "paginaFinal" => "3357"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/7745682"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            6 => array:3 [
              "identificador" => "bib0035"
              "etiqueta" => "&#91;7&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Hepatitis B virus replication is regulated by the acetylation status of hepatitis B virus cccDNA-bound H3 and H4 histones"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "T&#46; Pollicino"
                            1 => "L&#46; Belloni"
                            2 => "G&#46; Raffa"
                            3 => "N&#46; Pediconi"
                            4 => "G&#46; Squadrito"
                            5 => "G&#46; Raimondo"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1053/j.gastro.2006.01.001"
                      "Revista" => array:7 [
                        "tituloSerie" => "Gastroenterology"
                        "fecha" => "2006"
                        "volumen" => "130"
                        "numero" => "3"
                        "paginaInicial" => "823"
                        "paginaFinal" => "837"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16530522"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            7 => array:3 [
              "identificador" => "bib0040"
              "etiqueta" => "&#91;8&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Alpha-interferon suppresses hepadnavirus transcription by altering epigenetic modification of cccDNA minichromosomes"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "F&#46; Liu"
                            1 => "M&#46; Campagna"
                            2 => "Y&#46; Qi"
                            3 => "X&#46; Zhao"
                            4 => "F&#46; Guo"
                            5 => "C&#46; Xu"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "tituloSerie" => "PLoS Pathog"
                        "fecha" => "2013"
                        "volumen" => "9"
                        "numero" => "9"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            8 => array:3 [
              "identificador" => "bib0045"
              "etiqueta" => "&#91;9&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Nuclear HBx binds the HBV minichromosome and modifies the epigenetic regulation of cccDNA function"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Belloni"
                            1 => "T&#46; Pollicino"
                            2 => "F&#46; De Nicola"
                            3 => "F&#46; Guerrieri"
                            4 => "G&#46; Raffa"
                            5 => "M&#46; Fanciulli"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1073/pnas.0908365106"
                      "Revista" => array:8 [
                        "tituloSerie" => "Proc Natl Acad Sci U S A"
                        "fecha" => "2009"
                        "volumen" => "106"
                        "numero" => "47"
                        "paginaInicial" => "19975"
                        "paginaFinal" => "19979"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19906987"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S1470204512702267"
                          "estado" => "S300"
                          "issn" => "14702045"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            9 => array:3 [
              "identificador" => "bib0050"
              "etiqueta" => "&#91;10&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "IFN-alpha inhibits HBV transcription and replication in cell culture and in humanized mice by targeting the epigenetic regulation of the nuclear cccDNA minichromosome"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Belloni"
                            1 => "L&#46; Allweiss"
                            2 => "F&#46; Guerrieri"
                            3 => "N&#46; Pediconi"
                            4 => "T&#46; Volz"
                            5 => "T&#46; Pollicino"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1172/JCI58847"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Clin Invest"
                        "fecha" => "2012"
                        "volumen" => "122"
                        "numero" => "2"
                        "paginaInicial" => "529"
                        "paginaFinal" => "537"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22251702"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            10 => array:3 [
              "identificador" => "bib0055"
              "etiqueta" => "&#91;11&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Methyltransferase PRMT1 is a binding partner of HBx and a negative regulator of hepatitis B virus transcription"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "S&#46; Benhenda"
                            1 => "A&#46; Ducroux"
                            2 => "L&#46; Riviere"
                            3 => "B&#46; Sobhian"
                            4 => "M&#46;D&#46; Ward"
                            5 => "S&#46; Dion"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1128/JVI.02574-12"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Virol"
                        "fecha" => "2013"
                        "volumen" => "87"
                        "numero" => "8"
                        "paginaInicial" => "4360"
                        "paginaFinal" => "4371"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23388725"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            11 => array:3 [
              "identificador" => "bib0060"
              "etiqueta" => "&#91;12&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Replication of a chronic hepatitis B virus genotype F1b construct"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "S&#46; Hernandez"
                            1 => "G&#46; Jimenez"
                            2 => "V&#46; Alarcon"
                            3 => "C&#46; Prieto"
                            4 => "F&#46; Munoz"
                            5 => "C&#46; Riquelme"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s00705-015-2702-x"
                      "Revista" => array:7 [
                        "tituloSerie" => "Arch Virol"
                        "fecha" => "2016"
                        "volumen" => "161"
                        "numero" => "3"
                        "paginaInicial" => "583"
                        "paginaFinal" => "594"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/26620585"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            12 => array:3 [
              "identificador" => "bib0065"
              "etiqueta" => "&#91;13&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The enzymes LSD1 and Set1A cooperate with the viral protein HBx to establish an active hepatitis B viral chromatin state"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "V&#46; Alarcon"
                            1 => "S&#46; Hernandez"
                            2 => "L&#46; Rubio"
                            3 => "F&#46; Alvarez"
                            4 => "Y&#46; Flores"
                            5 => "M&#46; Varas-Godoy"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1038/srep25901"
                      "Revista" => array:5 [
                        "tituloSerie" => "Sci Rep"
                        "fecha" => "2016"
                        "volumen" => "6"
                        "paginaInicial" => "25901"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/27174370"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            13 => array:3 [
              "identificador" => "bib0070"
              "etiqueta" => "&#91;14&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "HBx relieves chromatin-mediated transcriptional repression of hepatitis B viral cccDNA involving SETDB1 histone methyltransferase"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Riviere"
                            1 => "L&#46; Gerossier"
                            2 => "A&#46; Ducroux"
                            3 => "S&#46; Dion"
                            4 => "Q&#46; Deng"
                            5 => "M&#46;L&#46; Michel"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.jhep.2015.06.023"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Hepatol"
                        "fecha" => "2015"
                        "volumen" => "63"
                        "numero" => "5"
                        "paginaInicial" => "1093"
                        "paginaFinal" => "1102"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/26143443"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            14 => array:3 [
              "identificador" => "bib0075"
              "etiqueta" => "&#91;15&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Mapping of histone modifications in episomal HBV cccDNA uncovers an unusual chromatin organization amenable to epigenetic manipulation"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "P&#46; Tropberger"
                            1 => "A&#46; Mercier"
                            2 => "M&#46; Robinson"
                            3 => "W&#46; Zhong"
                            4 => "D&#46;E&#46; Ganem"
                            5 => "M&#46; Holdorf"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1073/pnas.1518090112"
                      "Revista" => array:7 [
                        "tituloSerie" => "Proc Natl Acad Sci U S A"
                        "fecha" => "2015"
                        "volumen" => "112"
                        "numero" => "42"
                        "paginaInicial" => "E5715"
                        "paginaFinal" => "24"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/26438841"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            15 => array:3 [
              "identificador" => "bib0080"
              "etiqueta" => "&#91;16&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "SIRT3 restricts HBV transcription and replication via epigenetic regulation of cccDNA involving SUV39H1 and SETD1A histone methyltransferases"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "J&#46;H&#46; Ren"
                            1 => "J&#46;L&#46; Hu"
                            2 => "S&#46;T&#46; Cheng"
                            3 => "H&#46;B&#46; Yu"
                            4 => "V&#46;K&#46;W&#46; Wong"
                            5 => "B&#46;Y&#46;K&#46; Law"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1002/hep.510240222"
                      "Revista" => array:3 [
                        "tituloSerie" => "Hepatology"
                        "fecha" => "2018"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/8690415"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            16 => array:3 [
              "identificador" => "bib0085"
              "etiqueta" => "&#91;17&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Shaping chromatin in the nucleus&#58; the bricks and the architects"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "D&#46; Sitbon"
                            1 => "K&#46; Podsypanina"
                            2 => "T&#46; Yadav"
                            3 => "G&#46; Almouzni"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "LibroEditado" => array:2 [
                        "titulo" => "Cold Spring Harbor symposia on quantitative biology"
                        "serieFecha" => "2017"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            17 => array:3 [
              "identificador" => "bib0090"
              "etiqueta" => "&#91;18&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone variants on the move&#58; substrates for chromatin dynamics"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "P&#46;B&#46; Talbert"
                            1 => "S&#46; Henikoff"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1038/nrm.2016.148"
                      "Revista" => array:7 [
                        "tituloSerie" => "Nat Rev Mol Cell Biol"
                        "fecha" => "2017"
                        "volumen" => "18"
                        "numero" => "2"
                        "paginaInicial" => "115"
                        "paginaFinal" => "126"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/27924075"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            18 => array:3 [
              "identificador" => "bib0095"
              "etiqueta" => "&#91;19&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone variants&#58; structure&#44; function&#44; and implication in diseases"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "F&#46; Alvarez"
                            1 => "A&#46; Loyola"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "LibroEditado" => array:6 [
                        "editores" => "S&#46;S&#46;Mandal"
                        "titulo" => "Gene regulation&#44; epigenetics and hormone signaling&#46; 1"
                        "paginaInicial" => "209"
                        "paginaFinal" => "226"
                        "edicion" => "1 ed&#46;"
                        "serieFecha" => "2017"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            19 => array:3 [
              "identificador" => "bib0100"
              "etiqueta" => "&#91;20&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone H3&#46;1 and H3&#46;3 complexes mediate nucleosome assembly pathways dependent or independent of DNA synthesis"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "H&#46; Tagami"
                            1 => "D&#46; Ray-Gallet"
                            2 => "G&#46; Almouzni"
                            3 => "Y&#46; Nakatani"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/s0092-8674(03)01064-x"
                      "Revista" => array:7 [
                        "tituloSerie" => "Cell"
                        "fecha" => "2004"
                        "volumen" => "116"
                        "numero" => "1"
                        "paginaInicial" => "51"
                        "paginaFinal" => "61"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/14718166"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            20 => array:3 [
              "identificador" => "bib0105"
              "etiqueta" => "&#91;21&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Marking histone H3 variants&#58; how&#44; when and why&#63;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "A&#46; Loyola"
                            1 => "G&#46; Almouzni"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.tibs.2007.08.004"
                      "Revista" => array:7 [
                        "tituloSerie" => "Trends Biochem Sci"
                        "fecha" => "2007"
                        "volumen" => "32"
                        "numero" => "9"
                        "paginaInicial" => "425"
                        "paginaFinal" => "433"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/17764953"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            21 => array:3 [
              "identificador" => "bib0110"
              "etiqueta" => "&#91;22&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "PTMs on H3 variants before chromatin assembly potentiate their final epigenetic state"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "A&#46; Loyola"
                            1 => "T&#46; Bonaldi"
                            2 => "D&#46; Roche"
                            3 => "A&#46; Imhof"
                            4 => "G&#46; Almouzni"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.molcel.2006.08.019"
                      "Revista" => array:7 [
                        "tituloSerie" => "Mol Cell"
                        "fecha" => "2006"
                        "volumen" => "24"
                        "numero" => "2"
                        "paginaInicial" => "309"
                        "paginaFinal" => "316"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/17052464"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            22 => array:3 [
              "identificador" => "bib0115"
              "etiqueta" => "&#91;23&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone H3&#46;3 is enriched in covalent modifications associated with active chromatin"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "E&#46; McKittrick"
                            1 => "P&#46;R&#46; Gafken"
                            2 => "K&#46; Ahmad"
                            3 => "S&#46; Henikoff"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1073/pnas.0308092100"
                      "Revista" => array:8 [
                        "tituloSerie" => "Proc Natl Acad Sci U S A"
                        "fecha" => "2004"
                        "volumen" => "101"
                        "numero" => "6"
                        "paginaInicial" => "1525"
                        "paginaFinal" => "1530"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/14732680"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S0959804919302977"
                          "estado" => "S300"
                          "issn" => "09598049"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            23 => array:3 [
              "identificador" => "bib0120"
              "etiqueta" => "&#91;24&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Distinct factors control histone variant H3&#46;3 localization at specific genomic regions"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "A&#46;D&#46; Goldberg"
                            1 => "L&#46;A&#46; Banaszynski"
                            2 => "K&#46;M&#46; Noh"
                            3 => "P&#46;W&#46; Lewis"
                            4 => "S&#46;J&#46; Elsaesser"
                            5 => "S&#46; Stadler"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.cell.2010.01.003"
                      "Revista" => array:7 [
                        "tituloSerie" => "Cell"
                        "fecha" => "2010"
                        "volumen" => "140"
                        "numero" => "5"
                        "paginaInicial" => "678"
                        "paginaFinal" => "691"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20211137"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            24 => array:3 [
              "identificador" => "bib0125"
              "etiqueta" => "&#91;25&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The death-associated protein DAXX is a novel histone chaperone involved in the replication-independent deposition of H3&#46;3"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "P&#46; Drane"
                            1 => "K&#46; Ouararhni"
                            2 => "A&#46; Depaux"
                            3 => "M&#46; Shuaib"
                            4 => "A&#46; Hamiche"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1101/gad.566910"
                      "Revista" => array:7 [
                        "tituloSerie" => "Genes Dev"
                        "fecha" => "2010"
                        "volumen" => "24"
                        "numero" => "12"
                        "paginaInicial" => "1253"
                        "paginaFinal" => "1265"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20504901"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            25 => array:3 [
              "identificador" => "bib0130"
              "etiqueta" => "&#91;26&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Heterochromatin formation in the mouse embryo requires critical residues of the histone variant H3&#46;3"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "A&#46; Santenard"
                            1 => "C&#46; Ziegler-Birling"
                            2 => "M&#46; Koch"
                            3 => "L&#46; Tora"
                            4 => "A&#46;J&#46; Bannister"
                            5 => "M&#46;E&#46; Torres-Padilla"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1038/ncb2089"
                      "Revista" => array:7 [
                        "tituloSerie" => "Nat Cell Biol"
                        "fecha" => "2010"
                        "volumen" => "12"
                        "numero" => "9"
                        "paginaInicial" => "853"
                        "paginaFinal" => "862"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20676102"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            26 => array:3 [
              "identificador" => "bib0135"
              "etiqueta" => "&#91;27&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone H3&#46;3 incorporation provides a unique and functionally essential telomeric chromatin in embryonic stem cells"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46;H&#46; Wong"
                            1 => "H&#46; Ren"
                            2 => "E&#46; Williams"
                            3 => "J&#46; McGhie"
                            4 => "S&#46; Ahn"
                            5 => "M&#46; Sim"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1101/gr.084947.108"
                      "Revista" => array:7 [
                        "tituloSerie" => "Genome Res"
                        "fecha" => "2009"
                        "volumen" => "19"
                        "numero" => "3"
                        "paginaInicial" => "404"
                        "paginaFinal" => "414"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19196724"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            27 => array:3 [
              "identificador" => "bib0140"
              "etiqueta" => "&#91;28&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Hira-dependent histone H3&#46;3 deposition facilitates PRC2 recruitment at developmental loci in ES cells"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46;A&#46; Banaszynski"
                            1 => "D&#46; Wen"
                            2 => "S&#46; Dewell"
                            3 => "S&#46;J&#46; Whitcomb"
                            4 => "M&#46; Lin"
                            5 => "N&#46; Diaz"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.cell.2013.08.061"
                      "Revista" => array:7 [
                        "tituloSerie" => "Cell"
                        "fecha" => "2013"
                        "volumen" => "155"
                        "numero" => "1"
                        "paginaInicial" => "107"
                        "paginaFinal" => "120"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24074864"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            28 => array:3 [
              "identificador" => "bib0145"
              "etiqueta" => "&#91;29&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone H3&#46;3 is required for endogenous retroviral element silencing in embryonic stem cells"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "S&#46;J&#46; Elsasser"
                            1 => "K&#46;M&#46; Noh"
                            2 => "N&#46; Diaz"
                            3 => "C&#46;D&#46; Allis"
                            4 => "L&#46;A&#46; Banaszynski"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1038/nature14345"
                      "Revista" => array:8 [
                        "tituloSerie" => "Nature"
                        "fecha" => "2015"
                        "volumen" => "522"
                        "numero" => "7555"
                        "paginaInicial" => "240"
                        "paginaFinal" => "244"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25938714"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S0161642012010470"
                          "estado" => "S300"
                          "issn" => "01616420"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            29 => array:3 [
              "identificador" => "bib0150"
              "etiqueta" => "&#91;30&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Full-genome sequence of a hepatitis B virus genotype f1b clone from a chronically infected chilean patient"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "S&#46; Hernandez"
                            1 => "M&#46; Venegas"
                            2 => "J&#46; Brahm"
                            3 => "R&#46;A&#46; Villanueva"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1128/genomeA.00332-14"
                      "Revista" => array:5 [
                        "tituloSerie" => "Genome Announc"
                        "fecha" => "2014"
                        "volumen" => "2"
                        "numero" => "5"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24744341"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            30 => array:3 [
              "identificador" => "bib0155"
              "etiqueta" => "&#91;31&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Histone variant H3&#46;3 stimulates HSP70 transcription through cooperation with HP1gamma"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "H&#46; Kim"
                            1 => "K&#46; Heo"
                            2 => "J&#46; Choi"
                            3 => "K&#46; Kim"
                            4 => "W&#46; An"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1093/nar/gkr529"
                      "Revista" => array:8 [
                        "tituloSerie" => "Nucleic Acids Res"
                        "fecha" => "2011"
                        "volumen" => "39"
                        "numero" => "19"
                        "paginaInicial" => "8329"
                        "paginaFinal" => "8341"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/21742762"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S0959804913002219"
                          "estado" => "S300"
                          "issn" => "09598049"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            31 => array:3 [
              "identificador" => "bib0160"
              "etiqueta" => "&#91;32&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Understanding nucleosome dynamics and their links to gene expression and DNA replication"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "W&#46;K&#46;M&#46; Lai"
                            1 => "B&#46;F&#46; Pugh"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1038/nrm.2017.47"
                      "Revista" => array:7 [
                        "tituloSerie" => "Nat Rev Mol Cell Biol"
                        "fecha" => "2017"
                        "volumen" => "18"
                        "numero" => "9"
                        "paginaInicial" => "548"
                        "paginaFinal" => "562"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/28537572"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            32 => array:3 [
              "identificador" => "bib0165"
              "etiqueta" => "&#91;33&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Gene therapy for chronic HBV-can we eliminate cccDNA&#63;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "K&#46; Bloom"
                            1 => "M&#46;B&#46; Maepa"
                            2 => "A&#46; Ely"
                            3 => "P&#46; Arbuthnot"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "tituloSerie" => "Genes &#40;Basel&#41;"
                        "fecha" => "2018"
                        "volumen" => "9"
                        "numero" => "4"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            33 => array:3 [
              "identificador" => "bib0170"
              "etiqueta" => "&#91;34&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Transcription of hepatitis B virus covalently closed circular DNA is regulated by CpG methylation during chronic infection"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "Y&#46; Zhang"
                            1 => "R&#46; Mao"
                            2 => "R&#46; Yan"
                            3 => "D&#46; Cai"
                            4 => "Y&#46; Zhang"
                            5 => "H&#46; Zhu"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "tituloSerie" => "PLoS One"
                        "fecha" => "2014"
                        "volumen" => "9"
                        "numero" => "10"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            34 => array:3 [
              "identificador" => "bib0175"
              "etiqueta" => "&#91;35&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Canonical and variant forms of histone H3 are deposited onto the human cytomegalovirus genome during lytic and latent infections"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "E&#46;R&#46; Albright"
                            1 => "R&#46;F&#46; Kalejta"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1128/JVI.01220-16"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Virol"
                        "fecha" => "2016"
                        "volumen" => "90"
                        "numero" => "22"
                        "paginaInicial" => "10309"
                        "paginaFinal" => "10320"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/27605676"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            35 => array:3 [
              "identificador" => "bib0180"
              "etiqueta" => "&#91;36&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The histone variant H3&#46;3 regulates gene expression during lytic infection with herpes simplex virus type 1"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "B&#46;J&#46; Placek"
                            1 => "J&#46; Huang"
                            2 => "J&#46;R&#46; Kent"
                            3 => "J&#46; Dorsey"
                            4 => "L&#46; Rice"
                            5 => "N&#46;W&#46; Fraser"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1128/JVI.01276-08"
                      "Revista" => array:7 [
                        "tituloSerie" => "J Virol"
                        "fecha" => "2009"
                        "volumen" => "83"
                        "numero" => "3"
                        "paginaInicial" => "1416"
                        "paginaFinal" => "1421"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19004946"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            36 => array:3 [
              "identificador" => "bib0185"
              "etiqueta" => "&#91;37&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Chromatin dynamics during lytic infection with herpes simplex virus 1"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "K&#46;L&#46; Conn"
                            1 => "L&#46;M&#46; Schang"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.3390/v5071758"
                      "Revista" => array:7 [
                        "tituloSerie" => "Viruses"
                        "fecha" => "2013"
                        "volumen" => "5"
                        "numero" => "7"
                        "paginaInicial" => "1758"
                        "paginaFinal" => "1786"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23863878"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            37 => array:3 [
              "identificador" => "bib0190"
              "etiqueta" => "&#91;38&#93;"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Prevalence of hepatitis B virus genotypes in chronic carriers in Santiago&#44; Chile"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "M&#46; Venegas"
                            1 => "G&#46; Munoz"
                            2 => "C&#46; Hurtado"
                            3 => "L&#46; Alvarez"
                            4 => "M&#46; Velasco"
                            5 => "R&#46;A&#46; Villanueva"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s00705-008-0231-6"
                      "Revista" => array:8 [
                        "tituloSerie" => "Arch Virol"
                        "fecha" => "2008"
                        "volumen" => "153"
                        "numero" => "11"
                        "paginaInicial" => "2129"
                        "paginaFinal" => "2132"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/18953483"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S0002939416301970"
                          "estado" => "S300"
                          "issn" => "00029394"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
          ]
        ]
      ]
    ]
    "agradecimientos" => array:2 [
      0 => array:4 [
        "identificador" => "xack515645"
        "titulo" => "Acknowledgements"
        "texto" => "<p id="par0145" class="elsevierStylePara elsevierViewall">Laboratory members for critical suggestions&#46;</p>"
        "vista" => "all"
      ]
      1 => array:2 [
        "identificador" => "xack515646"
        "vista" => "all"
      ]
    ]
  ]
  "idiomaDefecto" => "en"
  "url" => "/16652681/000000210000000C/v1_202102250957/S1665268120301769/v1_202102250957/en/main.assets"
  "Apartado" => array:4 [
    "identificador" => "78265"
    "tipo" => "SECCION"
    "en" => array:2 [
      "titulo" => "Original Articles"
      "idiomaDefecto" => true
    ]
    "idiomaDefecto" => "en"
  ]
  "PDF" => "https://static.elsevier.es/multimedia/16652681/000000210000000C/v1_202102250957/S1665268120301769/v1_202102250957/en/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/"
  "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1665268120301769?idApp=UINPBA00004N"
]
Article information
ISSN: 16652681
Original language: English
The statistics are updated each day
Year/Month Html Pdf Total
2024 November 11 1 12
2024 October 35 11 46
2024 September 21 17 38
2024 August 15 24 39
2024 July 33 9 42
2024 June 18 10 28
2024 May 32 6 38
2024 April 37 13 50
2024 March 46 15 61
2024 February 39 7 46
2024 January 49 9 58
2023 December 51 9 60
2023 November 29 20 49
2023 October 74 12 86
2023 September 26 11 37
2023 August 33 8 41
2023 July 30 17 47
2023 June 44 9 53
2023 May 82 5 87
2023 April 64 9 73
2023 March 54 5 59
2023 February 37 8 45
2023 January 29 3 32
2022 December 34 12 46
2022 November 38 17 55
2022 October 42 10 52
2022 September 28 9 37
2022 August 27 10 37
2022 July 21 11 32
2022 June 26 4 30
2022 May 30 11 41
2022 April 64 13 77
2022 March 25 10 35
2022 February 40 9 49
2022 January 39 10 49
2021 December 32 15 47
2021 November 27 11 38
2021 October 48 18 66
2021 September 22 14 36
2021 August 45 6 51
2021 July 12 13 25
2021 June 15 19 34
2021 May 33 19 52
2021 April 152 35 187
2021 March 53 11 64
2021 February 30 7 37
2021 January 19 7 26
2020 December 7 8 15
2020 November 8 4 12
2020 October 6 5 11
Show all

Follow this link to access the full text of the article

es en pt

¿Es usted profesional sanitario apto para prescribir o dispensar medicamentos?

Are you a health professional able to prescribe or dispense drugs?

Você é um profissional de saúde habilitado a prescrever ou dispensar medicamentos