A targeted RNA interference screen reveals novel epigenetic factors that regulate herpesviral gene expression.
A targeted RNA interference screen reveals novel epigenetic factors that regulate herpesviral gene expression.
复制标题
靶向 RNA 干扰筛选揭示了调节疱疹病毒基因表达的新型表观遗传因素。
DOI：
10.1128/mbio.01086-13
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发表时间：
2014-02-04
期刊：
影响因子：
6.4
通讯作者：
Knipe DM
中科院分区：
文献类型：
--
作者：
Oh HS;Bryant KF;Nieland TJ;Mazumder A;Bagul M;Bathe M;Root DE;Knipe DM
单纯疱疹病毒(HSV)利用和颠覆宿主染色质机制在哺乳动物细胞中表达其裂解基因产物。宿主细胞试图通过表观遗传机制沉默传入的病毒基因组，但病毒VP16和ICP0蛋白通过招募其他宿主表观遗传因子来促进病毒基因组上的活性染色质。然而，对VP16和ICP0的依赖在不同的细胞系中是不同的，这意味着表观遗传因子对HSV基因表达的功能贡献取决于细胞类型。在这项研究中，我们对U2OS骨肉瘤细胞中参与调节单纯疱疹病毒(HSV)基因表达的细胞染色质因子进行了靶向RNA干扰(RNAi)筛选，U2OS骨肉瘤细胞系是一种补充ICP0突变和VP16突变病毒复制的细胞系。在这个筛选中，我们发现了与在其他类型的细胞中一样调节U2OS细胞中HSV基因表达的染色质因子的一般类别，包括组蛋白去甲基酶(HDMS)、组蛋白去乙酰基酶(HDAC)、组蛋白乙酰转移酶(HATS)和染色质重塑因子，但这些类别中的特定因子与以前在其他细胞类型中发现的那些不同。例如，KDM3A和KDM1A(LSD1)都是去甲基化的H3K9，但KDM3A出现在我们的U2OS细胞屏幕上。此外，小干扰RNA(SiRNA)和抑制剂研究支持这样的观点，即如之前观察到的那样，KDM1A在HeLa细胞中更关键，而KDM3A在U2OS细胞中更关键。这些结果表明，不同的细胞染色质因子在不同的细胞系中对HSV基因组施加的正负表观遗传效应是至关重要的。在进入宿主细胞核后，单纯疱疹病毒基因组受到宿主表观遗传沉默机制的影响。病毒蛋白招募细胞表观遗传激活蛋白来逆转和对抗细胞沉默机制。一些参与HSV基因表达的宿主沉默和激活功能已经被确定，但有迹象表明，宿主细胞因子可能在不同的细胞类型中有所不同。在这项研究中，我们对骨肉瘤细胞中参与HSV基因调控的染色质因子进行了筛选，我们发现在这些细胞中对HSV基因表达至关重要的染色质因子与以前研究的细胞类型的染色质因子不同。这些结果表明，在不同的细胞系和细胞类型中起作用的特定染色质因子可能不同。这对正在开发的表观遗传药物有影响。
Herpes simplex virus (HSV) utilizes and subverts host chromatin mechanisms to express its lytic gene products in mammalian cells. The host cell attempts to silence the incoming viral genome by epigenetic mechanisms, but the viral VP16 and ICP0 proteins promote active chromatin on the viral genome by recruiting other host epigenetic factors. However, the dependence on VP16 and ICP0 differs in different cell lines, implying cell type-dependent functional contributions of epigenetic factors for HSV gene expression. In this study, we performed a targeted RNA interference (RNAi) screen for cellular chromatin factors that are involved in regulation of herpes simplex virus (HSV) gene expression in U2OS osteosarcoma cells, a cell line that complements ICP0 mutant and VP16 mutant virus replication. In this screen, we found the same general classes of chromatin factors that regulate HSV gene expression in U2OS cells as in other cell types, including histone demethylases (HDMs), histone deacetylases (HDACs), histone acetyltransferases (HATs), and chromatin-remodeling factors, but the specific factors within these classes are different from those identified previously for other cell types. For example, KDM3A and KDM1A (LSD1) both demethylate mono- and dimethylated H3K9, but KDM3A emerged in our screen of U2OS cells. Further, small interfering RNA (siRNA) and inhibitor studies support the idea that KDM1A is more critical in HeLa cells, as observed previously, while KDM3A is more critical in U2OS cells. These results argue that different cellular chromatin factors are critical in different cell lines to carry out the positive and negative epigenetic effects exerted on the HSV genome. Upon entry into the host cell nucleus, the herpes simplex virus genome is subjected to host epigenetic silencing mechanisms. Viral proteins recruit cellular epigenetic activator proteins to reverse and counter the cellular silencing mechanisms. Some of the host silencing and activator functions involved in HSV gene expression have been identified, but there have been indications that the host cell factors may vary in different cell types. In this study, we performed a screen of chromatin factors involved in HSV gene regulation in osteosarcoma cells, and we found that the chromatin factors that are critical for HSV gene expression in these cells are different from those for previously studied cell types. These results argue that the specific chromatin factors operative in different cell lines and cell types may differ. This has implications for epigenetic drugs that are under development.