Epigenetic Regulation of Epstein-Barr Virus

R01的长期目标是了解表观遗传机制如何控制EB病毒(EBV)潜伏和致癌。EBV潜伏感染与多种类型的上皮性和淋巴系统恶性肿瘤有关。EBV感染对各种宿主细胞和环境的高度适应性表明，它利用了动态基因调控的基本细胞过程。已知EBV在不同的宿主细胞和肿瘤环境中适应不同的基因表达程序，称为潜伏型。这些潜伏期类型和病毒基因表达模式是由表观遗传因素决定的，包括核小体定位、组蛋白修饰、CpG DNA甲基化、转录因子占据和染色体构象。调控病毒和宿主DNA表观遗传控制的机制尚未完全了解，但对于了解病毒潜伏期和不同类型细胞中的肿瘤发生至关重要。我们一直在研究EBV建立和调节病毒和宿主基因组的表观遗传程序的过程。在之前的资助周期中，我们发现病毒被膜蛋白BNRF1是DAXX-组蛋白H3.3复合体的结合伙伴，并表明在感染的早期、潜伏期，这种相互作用是病毒染色质组装和基因表达所必需的。我们已经确定了EBNA1、EBNA2、CTCF、粘附素(RAD21)、EBF1、RBP JK和染色体构象的病毒和细胞转录因子结合位点，它们在潜伏期的建立过程中发生变化，并与不同的潜伏期类型相关。我们分析了在EB病毒诱导的B细胞永生化的多个阶段中染色质可及性和RNA表达的变化，以将基因表达与染色质结构相关联。我们还发现，病毒和宿主DNA甲基化编程依赖于病毒EBNA2和vmiRNAs，它们协调调节TET2的表达和胞嘧啶的羟甲基化和去甲基化。我们现在建议进一步推进这些研究，以更好地理解表观遗传机制在控制EBV潜伏期和致瘤性中的作用。我们将测试最重要的假设，即EBV重新编程具有表观遗传机制，以实现病毒基因组的持久性和转录可塑性，从而驱动EBV相关的肿瘤发生。

The long-term goal of this R01 is to understand how epigenetic mechanisms control Epstein-Barr Virus (EBV) latency and carcinogenesis. EBV latent infection is associated with a diverse spectrum of epithelial and lymphoid malignancies. The highly adaptive nature of EBV infection to various host cells and environments suggests that it exploits fundamental cellular processes of dynamic gene regulation. EBV is known to adapt various gene expression programs, termed latency types, in different host cell and tumor environments. These latency types and viral gene expression patterns are determined by epigenetic factors ranging from nucleosome positioning, histone modifications, CpG DNA methylation, transcription factor occupancy, and chromosome conformation. The mechanisms regulating viral and host DNA epigenetic controls are not fully understood but are critical for understanding viral latency and oncogenesis in diverse cell types. We have been investigating the process through which EBV establishes and regulates the epigenetic program of both viral and host genomes. In the previous funding cycles, we identified the viral tegument protein BNRF1 as a binding partner of DAXX-histone H3.3 complex and showed that this interaction is required for viral chromatin assembly and gene expression during the early, pre-latent phase of infection. We have identified viral and cellular transcription factor binding sites for EBNA1, EBNA2, CTCF, cohesin (RAD21), EBF1, RBP JK and chromosome conformations that change during the establishment of latency and correlate with different latency types. We have assayed chromatin accessibility and RNA expression changes during the multiple stages of EBV-induced B-cell immortalization to correlate gene expression with chromatin architecture. We have also found that viral and host DNA methylation programming depends on viral EBNA2 and vmiRNAs that coordinately regulate TET2 expression and cytosine hydroxymethylation and demethylation. We now propose to further advance these studies to better understand the role of epigenetic mechanisms in the control of EBV latency and oncogenicity. We will test the overarching hypothesis that EBV reprograms host epigenetic mechanisms to enable viral genome persistence and transcriptional plasticity that drives EBV-associated oncogenesis.