Cohesins Repress Kaposi's Sarcoma-Associated Herpesvirus Immediate Early Gene Transcription during Latency
Cohesins Repress Kaposi's Sarcoma-Associated Herpesvirus Immediate Early Gene Transcription during Latency
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DOI：
10.1128/jvi.00787-12
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发表时间：
2012-09-01
影响因子：
5.4
通讯作者：
Lieberman, Paul M.
中科院分区：
文献类型：
--
作者：
Chen, Horng-Shen;Wikramasinghe, Priyankara;Lieberman, Paul M.
染色质组织因子，如CTCF和粘附素已被牵连在复杂的病毒调控程序的控制。我们研究了CTCF和cohesins在控制卡波西肉瘤相关疱疹病毒（KSHV）从潜伏期到裂解周期的转换中的作用。我们发现，cohesin亚单位，而不是CTCF所需的抑制KSHV立即早期基因转录。缺失的粘附素亚基Rad 21，SMC 1，SMC 3导致裂解周期基因转录和病毒DNA复制。相反，CTCF的耗竭未能诱导裂解转录或DNA复制。染色质免疫沉淀与高通量测序（ChIP-Seq）显示，cohesins和CTCF结合到ORF 50的直接早期控制区域内的几个位点，以及更远的5'位点，这些位点也调节了发散转录的ORF 45-ORF 46-ORF 47基因簇。Rad 21耗竭导致ORF 45、ORF 46、ORF 47和ORF 50转录物的稳健增加，其动力学与丁酸钠化学诱导所观察到的动力学相似。在潜伏期期间，ORF 45和ORF 50转录起始位点之间的染色质富含组蛋白H3 K4 me 3，ORF 45启动子处的H3 K9 ac升高，ORF 50启动子处的H3 K27 me 3升高。暂停形式的RNA聚合酶II（Pol II）与ORF 45启动子区在潜伏期松散相关，但在Rad 21耗竭诱导的再激活后转化为活性延长形式。丁酸处理引起的快速解离的cohesins和损失的CTCF结合在立即早期基因位点，表明cohesins可能是丁酸介导的裂解诱导的直接目标。我们的研究结果牵连的KSHV裂解基因激活的主要阻遏物，并表明，他们的功能协同CTCF调节潜伏和裂解基因活性之间的切换。
Chromatin-organizing factors such as CTCF and cohesins have been implicated in the control of complex viral regulatory programs. We investigated the role of CTCF and cohesins in the control of the switch from latency to the lytic cycle for Kaposi's sarcoma-associated herpesvirus (KSHV). We found that cohesin subunits but not CTCF are required for the repression of KSHV immediate early gene transcription. Depletion of the cohesin subunits Rad21, SMC1, and SMC3 resulted in lytic cycle gene transcription and viral DNA replication. In contrast, depletion of CTCF failed to induce lytic transcription or DNA replication. Chromatin immunoprecipitation with high-throughput sequencing (ChIP-Seq) revealed that cohesins and CTCF bound to several sites within the immediate early control region for ORF50 and to more distal 5' sites that also regulate the divergently transcribed ORF45-ORF46-ORF47 gene cluster. Rad21 depletion led to a robust increase in ORF45, ORF46, ORF47, and ORF50 transcripts, with similar kinetics to that observed with chemical induction by sodium butyrate. During latency, the chromatin between the ORF45 and ORF50 transcription start sites was enriched in histone H3K4me3, with elevated H3K9ac at the ORF45 promoter and elevated H3K27me3 at the ORF50 promoter. A paused form of RNA polymerase II (Pol II) was loosely associated with the ORF45 promoter region during latency but was converted to an active elongating form upon reactivation induced by Rad21 depletion. Butyrate treatment caused a rapid dissociation of cohesins and loss of CTCF binding at the immediate early gene locus, suggesting that cohesins may be a direct target of butyrate-mediated lytic induction. Our findings implicate cohesins as a major repressor of KSHV lytic gene activation and show that they function coordinately with CTCF to regulate the switch between latent and lytic gene activity.