Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, 1664 N Virginia Street, Reno, NV 89557, USA.
Viruses. 2020 Apr 9;12(4):420. doi: 10.3390/v12040420.
Kaposi's sarcoma-associated herpesvirus (KSHV) causes multiple malignancies in immunocompromised individuals. KSHV primarily establishes a lifelong latency in infected humans during which only a subset of viral genes is expressed while most of the viral genome remains transcriptionally silent with condensed chromatin. However, during the lytic phase, the viral genome undergoes dramatic changes in chromatin landscape leading to a transcriptionally active state with the expression of most of the viral genes and production of progeny virions. Multiple cellular and viral factors influence the epigenetic gene regulation and transitioning of virus from latency to the lytic state. We have earlier shown that KSHV ORF59, viral processivity factor, binds to a protein arginine methyl transferase 5 (PRMT5) to alter the histone arginine methylation during reactivation. Additionally, ORF59 has been shown to interact with most abundantly expressed KSHV long noncoding polyadenylated nuclear RNA (PAN RNA), which associates with the viral epigenome during reactivation. Interestingly, PAN RNA interacts with UTX and JMJD3, cellular H3K27me3 demethylases, and removes the repressive marks on the chromatin. In this study, we report that the recruitment of histone demethylases to the viral chromatin is facilitated by the expression of ORF59 protein and PAN RNA. Using biochemical and localization assays including co-immunoprecipitation and immunofluorescence, we demonstate ORF59 localizes with UTX and JMJD3. Our results confirm that PAN RNA enhances the interaction of ORF59 with the chromatin modifying enzymes UTX and JMJD3.
卡波西肉瘤相关疱疹病毒（KSHV）可导致免疫功能低下个体的多种恶性肿瘤。KSHV 主要在受感染的人类中建立终身潜伏状态，在此期间，只有一小部分病毒基因表达，而大部分病毒基因组仍处于转录沉默状态，染色质浓缩。然而，在裂解期，病毒基因组经历染色质景观的剧烈变化，导致转录活跃状态，大多数病毒基因表达，并产生子代病毒粒子。多种细胞和病毒因素影响表观遗传基因调控和病毒从潜伏状态向裂解状态的转变。我们之前已经表明，KSHV ORF59，病毒持续性因子，与蛋白精氨酸甲基转移酶 5（PRMT5）结合，在病毒重新激活过程中改变组蛋白精氨酸甲基化。此外，ORF59 已被证明与大多数表达丰富的 KSHV 长非编码多聚腺苷酸化核 RNA（PAN RNA）相互作用，该 RNA 在重新激活期间与病毒表观基因组结合。有趣的是，PAN RNA 与 UTX 和 JMJD3，细胞 H3K27me3 去甲基化酶相互作用，并去除染色质上的抑制性标记。在这项研究中，我们报告了 ORF59 蛋白和 PAN RNA 的表达促进了组蛋白去甲基酶向病毒染色质的募集。通过生化和定位分析，包括共免疫沉淀和免疫荧光，我们证明 ORF59 与 UTX 和 JMJD3 定位。我们的结果证实，PAN RNA 增强了 ORF59 与染色质修饰酶 UTX 和 JMJD3 的相互作用。
