Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Latency-Associated Nuclear Antigen Regulates the KSHV Epigenome by Association with the Histone Demethylase KDM3A
Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Latency-Associated Nuclear Antigen Regulates the KSHV Epigenome by Association with the Histone Demethylase KDM3A
复制标题
DOI：
10.1128/jvi.00011-13
复制
发表时间：
2013-06-01
影响因子：
5.4
通讯作者：
Izumiya, Yoshihiro
中科院分区：
文献类型：
--
作者：
Kim, Kevin Y.;Huerta, Steve B.;Izumiya, Yoshihiro
卡波西肉瘤相关疱疹病毒（KSHV）潜伏基因组与宿主组蛋白相连，形成一个微型染色体，也称为“附加体”。“组蛋白是染色质的核心成分，被各种组蛋白靶向酶严重修饰。组蛋白的翻译后修饰显著影响转录因子的可及性，从而对基因表达产生深远的影响。最近的研究表明，KSHV附加体上的表观遗传标记组织良好，例如在自然感染的细胞中，立即早期和潜伏基因启动子不存在组蛋白H3赖氨酸9（H3 K9）甲基化，这是一种异染色质组蛋白标记。本研究揭示了通过由拉娜和H3 K9 me 1/2组蛋白去甲基化酶JMJD 1A/KDM 3A组成的复合物对KSHV表观基因组调控的机制。该复合物从稳定表达拉娜的HeLa细胞核提取物中分离，并通过免疫共沉淀分析和纯化的蛋白质进行验证。KSHV基因组上的拉娜募集位点与自然感染细胞中的H3 K9 me 2组蛋白标记负相关，并且H3 K9的甲基化显著抑制拉娜与组蛋白H3尾的结合。染色质免疫沉淀结合KSHV平铺阵列确定了复合物的募集位点，而拉娜表达的耗竭或KDM 3A结合缺陷突变体的过表达降低了KDM 3A向KSHV基因组的募集。最后，从潜伏性KSHV感染的细胞中去除KDM 3A表达显著抑制KSHV基因表达，导致KSHV在再激活期间复制减少。综上所述，我们的研究结果表明，拉娜可能在KSHV基因组上的表观遗传标记的调节中发挥作用，这部分是通过与组蛋白去甲基化酶KDM 3A相关联。
Kaposi's sarcoma-associated herpesvirus (KSHV) latent genomes are tethered to host histones to form a minichromosome also known as an "episome." Histones, which are core components of chromatin, are heavily modified by various histone-targeting enzymes. Posttranslational modifications of histones significantly influence accessibility of transcriptional factors and thus have profound effects on gene expression. Recent studies showed that epigenetic marks on the KSHV episome are well organized, exemplified by the absence of histone H3 lysine 9 (H3K9) methylation, a heterochromatic histone mark, from immediate early and latent gene promoters in naturally infected cells. The present study revealed a mechanistic insight into KSHV epigenome regulation via a complex consisting of LANA and the H3K9me1/2 histone demethylase JMJD1A/KDM3A. This complex was isolated from HeLa cell nuclear extracts stably expressing LANA and was verified by coimmunoprecipitation analyses and with purified proteins. LANA recruitment sites on the KSHV genome inversely correlated with H3K9me2 histone marks in naturally infected cells, and methylation of H3K9 significantly inhibited LANA binding to the histone H3 tail. Chromatin immunoprecipitation coupled with KSHV tiling arrays identified the recruitment sites of the complex, while depletion of LANA expression or overexpression of a KDM3A binding-deficient mutant decreased KDM3A recruitment to the KSHV genome. Finally, ablation of KDM3A expression from latently KSHV-infected cells significantly inhibited KSHV gene expression, leading to decreased KSHV replication during reactivation. Taken together, our results suggest that LANA may play a role in regulation of epigenetic marks on the KSHV genome, which is in part through association with the histone demethylase KDM3A.