Polycomb Repressive Complex 2 Silences Human Cytomegalovirus Transcription in Quiescent Infection Models
Polycomb Repressive Complex 2 Silences Human Cytomegalovirus Transcription in Quiescent Infection Models
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DOI：
10.1128/jvi.02420-13
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发表时间：
2013-12-01
影响因子：
5.4
通讯作者：
Kulesza, Caroline A.
中科院分区：
文献类型：
--
作者：
Abraham, Christopher G.;Kulesza, Caroline A.
以染色质为基础的疱疹病毒转录程序的调节作为调节感染结果的一种机制越来越受到重视。在裂解感染期间，转录允许的常染色质占主导地位，而在潜伏期，不能转录的异染色质结构域在裂解基因上丰富。可逆地沉默的兼性异染色质结构域经常富集组蛋白H3在赖氨酸27(H3K27me3)上三甲基化，这是一种由多梳抑制复合体2(PRC2)催化的修饰。对于PRC2在潜伏期抑制人巨细胞病毒(HCMV)裂解转录程序的要求还没有得到彻底的评估。因此，我们用PRC2活性的小分子抑制剂处理细胞，在高度易处理的THP1和NT2D1静止感染模型中干扰了PRC2的活性。与对照细胞相比，在感染HCMV的THP1或NT2D1细胞中，PRC2的破坏导致病毒转录水平和病毒蛋白检测的显著增加。利用染色质免疫沉淀，我们证明了由PRC2沉积的H3K27me3的富集量与裂解转录产量呈负相关，表明PRC2在病毒染色质上的催化活性直接抑制裂解转录。综上所述，我们的数据表明，PRC2介导的病毒转录抑制是建立和维持HCMV潜伏期的关键步骤。
Chromatin-based regulation of herpesviral transcriptional programs is increasingly appreciated as a mechanism for modulating infection outcomes. Transcriptionally permissive euchromatin predominates during lytic infection, whereas heterochromatin domains refractory to transcription are enriched at lytic genes during latency. Reversibly silenced facultative heterochromatin domains are often enriched for histone H3 trimethylated on lysine 27 (H3K27me3), a modification catalyzed by Polycomb repressive complex 2 (PRC2). The requirement for PRC2 in suppressing the human cytomegalovirus (HCMV) lytic transcriptional program during latency has not been thoroughly evaluated. Therefore, we disrupted PRC2 activity in the highly tractable THP1 and NT2D1 quiescent-infection models by treating cells with small-molecule inhibitors of PRC2 activity. Compared to control cells, disruption of PRC2 in HCMV-infected THP1 or NT2D1 cells resulted in significant increases in viral transcript levels and the detection of viral protein. Using chromatin immunoprecipitation, we demonstrated that enrichment of H3K27me3, deposited by PRC2, correlates inversely with lytic transcriptional output, suggesting that PRC2 catalytic activity at viral chromatin directly represses lytic transcription. Together, our data suggest that PRC2-mediated repression of viral transcription is a key step in the establishment and maintenance of HCMV latency.