Influence of ND10 components on epigenetic determinants of early KSHV latency establishment.
Influence of ND10 components on epigenetic determinants of early KSHV latency establishment.
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DOI：
10.1371/journal.ppat.1004274
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发表时间：
2014-07
期刊：
影响因子：
6.7
通讯作者：
Grundhoff A
中科院分区：
文献类型：
--
作者：
Günther T;Schreiner S;Dobner T;Tessmer U;Grundhoff A
我们之前已经证明，获得复杂的激活（H3K4me3、H3K9/K14ac）和抑制（H3K27me3）组蛋白修饰模式是 KSHV 潜伏期建立的标志。然而，塑造潜在组蛋白修饰景观的精确分子机制仍然未知。早幼粒细胞白血病核体 (PML-NB)，也称为核结构域 10 (ND10)，已成为先天免疫反应的介质，可以通过基于染色质的机制限制病毒基因表达。因此，尽管迄今为止 ND10 的功能几乎都是在生产性疱疹病毒感染模型中进行研究，但有人提出它们也可能有助于病毒潜伏期的建立。在这里，我们报告了第一个关于 ND10 在 KSHV 潜伏期建立过程中的作用的系统研究，并将 ND10 成分亚细胞分布的变化与早期感染阶段组蛋白修饰获取和宿主细胞基因表达的时间分析联系起来。我们的研究表明，KSHV 感染会导致短暂的干扰素反应，从而诱导 ND10 成分 PML 和 Sp100 的诱导，但 ND10 体的抑制不太可能有助于 KSHV 潜伏期的建立。相反，我们发现了可溶性 Sp100 蛋白的意想不到的作用，它可以有效且永久地从核质和染色质相关部分重新定位到不溶性基质中。我们表明 LANA 表达足以诱导 Sp100 重新定位，可能是通过介导 Sp100 的 SUMOylation。此外，我们证明，当抑制性 H3K27me3 标记首次在病毒基因组上积累时，可溶性 Sp100 的消耗恰好发生，并且 Sp100 的敲低（但不是 PML 或 Daxx）有利于 H3K27me3 的获得。总的来说，我们的数据支持一个模型，其中非 ND10 驻留 Sp100 充当多梳抑制复合物 2 (PRC2) 招募的负调节因子，并表明 KSHV 可能主动逃避 ND10 沉默机制，以促进潜在染色质的建立。 KSHV 是多种癌症的病原体，其中包括卡波西肉瘤，这是撒哈拉以南非洲地区最常见的肿瘤之一。由于这些癌症中的增殖细胞潜伏感染 KSHV，因此迫切需要阐明潜伏建立的分子基础。虽然众所周知，复杂的组蛋白修饰模式保留了潜在状态，但导致这种模式的初步建立和随后形成抑制性异染色质的机制仍然很大程度上未知。在过去的几年中，不同核区室的成分，即所谓的 ND10 或 PML 小体，已成为病毒染色质和基因表达的调节剂。在这里，我们首次系统分析了早期感染阶段 KSHV 和 ND10 成分之间的相互影响。我们发现，潜伏的 KSHV 感染极大地改变了可溶形式的 ND10 核心蛋白（称为 Sp100）的亚核分布。这种重新定位可能有助于促进多梳抑制复合物的募集和兼性异染色质的形成，因此我们提出可溶性 Sp100 是 KSHV 潜伏期建立的拮抗剂。我们的研究结果对于理解病毒潜伏期的建立具有重要意义，也为细胞染色质调控途径提供了宝贵的见解。
We have previously demonstrated that acquisition of intricate patterns of activating (H3K4me3, H3K9/K14ac) and repressive (H3K27me3) histone modifications is a hallmark of KSHV latency establishment. The precise molecular mechanisms that shape the latent histone modification landscape, however, remain unknown. Promyelocytic leukemia nuclear bodies (PML-NB), also called nuclear domain 10 (ND10), have emerged as mediators of innate immune responses that can limit viral gene expression via chromatin based mechanisms. Consequently, although ND10 functions thus far have been almost exclusively investigated in models of productive herpesvirus infection, it has been proposed that they also may contribute to the establishment of viral latency. Here, we report the first systematic study of the role of ND10 during KSHV latency establishment, and link alterations in the subcellular distribution of ND10 components to a temporal analysis of histone modification acquisition and host cell gene expression during the early infection phase. Our study demonstrates that KSHV infection results in a transient interferon response that leads to induction of the ND10 components PML and Sp100, but that repression by ND10 bodies is unlikely to contribute to KSHV latency establishment. Instead, we uncover an unexpected role for soluble Sp100 protein, which is efficiently and permanently relocalized from nucleoplasmic and chromatin-associated fractions into the insoluble matrix. We show that LANA expression is sufficient to induce Sp100 relocalization, likely via mediating SUMOylation of Sp100. Furthermore, we demonstrate that depletion of soluble Sp100 occurs precisely when repressive H3K27me3 marks first accumulate on viral genomes, and that knock-down of Sp100 (but not PML or Daxx) facilitates H3K27me3 acquisition. Collectively, our data support a model in which non-ND10 resident Sp100 acts as a negative regulator of polycomb repressive complex-2 (PRC2) recruitment, and suggest that KSHV may actively escape ND10 silencing mechanisms to promote establishment of latent chromatin. KSHV is the etiological agent of several cancers including Kaposi's sarcoma, one of the most frequent tumors in Sub-Saharan Africa. Since the proliferating cells in these cancers are latently infected with KSHV, there is an urgent need to elucidate the molecular basis underlying latency establishment. While it is well established that intricate histone modification patterns preserve the latent state, the mechanisms that lead to primary establishment of such patterns and subsequent formation of repressive heterochromatin remain largely unknown. During the last years, components of distinct nuclear compartments, so called ND10 or PML bodies, have emerged as modulators of viral chromatin and gene expression. Here, we present the first systematic analysis of the mutual influence between KSHV and ND10 components during the early infection phase. We find that latent KSHV infection dramatically alters the sub-nuclear distribution of the soluble form of a ND10 core protein termed Sp100. This relocalization likely serves to facilitate the recruitment of polycomb repressive complexes and formation of facultative heterochromatin, and we hence propose that soluble Sp100 is an antagonist of KSHV latency establishment. Our findings have important implications for the understanding of viral latency establishment and also provide valuable insight into cellular chromatin regulation pathways.
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Kaposi肉瘤相关的疱疹病毒调节蛋白的翻译后修饰 - SUMO和KSHV。
影响因子：
5.2
作者：
Campbell M;Izumiya Y
通讯作者：
Izumiya Y
DOI：
10.1083/jcb.112.5.785
发表时间：
1991-03
期刊：
The Journal of cell biology
影响因子：
--
作者：
Ascoli CA;Maul GG
通讯作者：
Maul GG
影响因子：
3.7
作者：
Cotter, MA;Robertson, ES
通讯作者：
Robertson, ES
影响因子：
5.4
作者：
Chelbi-Alix, MK;Quignon, F;De Thé, H
通讯作者：
De Thé, H
影响因子：
8
作者：
Carbone, R;Pearson, M;Pelicci, PG
通讯作者：
Pelicci, PG