VP16-dependent association of chromatin-modifying coactivators and underrepresentation of histones at immediate-early gene promoters during herpes simplex virus infection
VP16-dependent association of chromatin-modifying coactivators and underrepresentation of histones at immediate-early gene promoters during herpes simplex virus infection
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DOI：
10.1128/jvi.78.18.9689-9696.2004
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发表时间：
2004-09-01
影响因子：
5.4
通讯作者：
Triezenberg, SJ
中科院分区：
文献类型：
--
作者：
Herrera, FJ;Triezenberg, SJ
在单纯疱疹病毒1型(HSV-1)感染过程中，病毒粒子蛋白VP16激活病毒即刻早期(IE)基因的转录。遗传和生化分析表明，VP16的有效转录激活结构域可以与一般转录因子和几种类型的染色质修饰辅助激活蛋白相关联。后一种相互作用特别耐人寻味，因为先前的报告表明，HSV-1DNA在裂解感染期间不会变成核小体。在本工作中，我们用化学交联和免疫沉淀的方法检测了野生型HSV-1和缺乏VP16转录激活结构域的Rp5株感染HeLa细胞过程中IE基因启动子上激活子、一般转录因子和染色质修饰共激活子的存在。VP16和OCT-1在IE启动子上的存在不依赖于激活结构域。相反，在野生型感染中观察到RNA聚合酶II、TATA结合蛋白、组蛋白乙酰转移酶(p300和CBP)以及ATP依赖的重塑蛋白(BRG1和hBRM)与IE基因启动子相关，但在Rp5感染的细胞中没有或减少。与先前非核小体HSV-1 DNA的证据不同，组蛋白H3在感染早期被发现与病毒DNA相关。有趣的是，组蛋白H3在IE启动子上的表达不足，这取决于VP16激活结构域。因此，VP16激活域负责向IE启动子招募一般转录因子和辅助激活子，也负责显著减少组蛋白与这些启动子的关联。
During infection by herpes simplex virus type 1 (HSV-1), the virion protein VP16 activates the transcription of viral immediate-early (IE) genes. Genetic and biochemical assays have shown that the potent transcriptional activation domain of VP16 can associate with general transcription factors and with chromatin-modifying coactivator proteins of several types. The latter interactions are particularly intriguing because previous reports indicate that HSV-1 DNA does not become nucleosomal during lytic infection. In the present work, chemical cross-linking and immunoprecipitation assays were used to probe the presence of activators, general transcription factors, and chromatin-modifying coactivators; at IE gene promoters during infection of HeLa cells by wild-type HSV-1 and by RP5, a viral strain lacking the VP16 transcriptional activation domain. The presence of VP16 and Oct-1 at IE promoters did not depend on the activation domain. In contrast, association of RNA polymerase II, TATA-binding protein, histone acetyltransferases (p300 and CBP), and ATP-dependent remodeling proteins (BRG1 and hBRM) with IE gene promoters was observed in wild-type infections but was absent or reduced in cells infected by RP5. In contrast to the previous evidence for nonnucleosomal HSV-1 DNA, histone H3 was found associated with viral DNA at early times of infection. Interestingly, histone H3 was underrepresented on IE promoters in a manner dependent on the VP16 activation domain. Thus, the VP16 activation domain is responsible for recruiting general transcription factors and coactivators to IE promoters and also for dramatically reducing the association of histones with those promoters.