Regulation of EBV Latency by Chromosome Conformation

项目摘要 EB病毒是一种感染B淋巴细胞的人类γ疱疹病毒。EB病毒潜伏感染是 与几种人类恶性肿瘤相关，包括伯基特淋巴瘤（BL）和鼻咽淋巴瘤。 癌（NPC）。在潜伏期，EBV能够采用至少四种不同的基因表达程序， 被称为延迟类型。这些基因的表达程序是由交替启动子调控的 利用率由于潜伏期类型具有不同的免疫原性，因此控制病毒基因表达和 启动子选择是EBV建立长期感染的关键步骤。尽管进展 尽管如此，调节EBV基因表达的机制尚未阐明。分析 EB病毒潜伏启动子周围的染色质显示，不同的表观遗传模式对应于 不同的延迟类型。此外，我们发现细胞因子CTCF结合在几个关键区域， EBV基因组和调控启动子选择和病毒基因表达。我们还证明了CTCF 可以促进病毒启动子和EBV复制起点之间的交替染色质环， 提示染色质结构可有助于调节EBV潜伏类型。该提案结合 经典的生物化学方法和染色体构象分析，试图揭示三个作用， EBV基因组的三维结构在不同潜伏期病毒基因表达调控中的作用 类型本研究的目的是使用这种新的方法：1）确定CTCF/Cohesin相互作用的作用 在潜伏感染过程中调节EBV高阶染色质结构; 2）确定病毒的作用， 蛋白EBNA1在调节EBV基因组构象中的作用; 3）确定EBNA1是否促进细胞间的相互作用， 病毒-宿主和宿主-宿主染色体之间的染色体DNA相互作用;和4）测试PARP1 抑制可使EBV染色体结构和病毒基因表达失调。这个项目的目标是 以提高我们对调节EB病毒潜伏期类型的分子机制的理解。

Project Summary The Epstein-Barr virus is a human gamma herpesvirus that infects B-lymphocytes. The EBV latent infection is associated with several human malignancies, including Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC). During latency EBV is able to adopt at least four different gene expression programs that are referred to as latency types. These gene expression programs are regulated by alternative promoter utilization. Since the latency types are differentially immunogenic, the control of viral gene expression and promoter selection is a critical step for EBV to establish a long-term infection. Although progress has been made, the mechanism that regulates EBV gene expression has not yet been elucidated. The analysis of chromatin surrounding the EBV latent promoters revealed that different epigenetic patterns correspond to different latency types. Moreover, we found that the cellular factor CTCF binds at several key regions of the EBV genome and regulates promoter selection and viral gene expression. We have also proved that CTCF can promote alternative chromatin loops between the viral promoters and the origin of replication of EBV, suggesting that chromatin structure can contribute to regulate EBV latency types. This proposal, combining classical biochemical methodology and chromosome conformation analysis, seeks to reveal the role of three- dimensional architecture of the EBV genome in the regulation of viral gene expression in different latency types. The aim of this study is to use this novel approach to: 1) determine the role of CTCF/Cohesin interaction in the regulation of EBV high-order chromatin structure during latent infection; 2) determine the role of the viral protein EBNA1 in the regulation of EBV genome conformation; 3) determine if EBNA1 promotes inter- chromosomal DNA interactions between virus-host and host-host chromosomes; and 4) test if PARP1 inhibition deregulates the EBV chromosome architecture and viral gene expression. The goal of this project is to improve our understanding of the molecular mechanism that regulates EBV latency types.