Chromatin Regulation of KSHV Primary Infection

项目总结 (请参阅说明)： KSHV是一种人类伽马疱疹病毒，是Kaposi肉瘤(KS)的病原体，与胸腔积液淋巴瘤(PEL)和多中心Castleman病(MCD)密切相关。B淋巴细胞的潜伏感染和内皮细胞的持续感染被认为是KSHV相关性疾病的主要驱动力。建立潜伏感染需要形成一个稳定的环状微染色体，它表达一组有限的病毒基因。建立微染色体形成和将基因表达限制在潜伏期类的机制尚不清楚。我们之前发表的研究表明，染色质边界因子，如CTCF，组织病毒染色体结构和组蛋白修饰模式，对基因组稳定和限制基因表达至关重要。CTCF与粘附素(如SMCL、SMC3、Rad21)相互作用形成高阶DNA构象，对于细胞分裂过程中的染色体传递和协调转录调控是重要的。本课题组最近的研究表明，在潜伏感染的PEL细胞中，CTCF-粘附素介导了KSHV基因组潜伏控制区和裂解控制区之间的相互作用。新的初步数据表明，裂解即刻早期基因是通过涉及CTCF和粘附素的染色质结构来协调调节的，而粘附素是抑制裂解基因转录所必需的。此外，CTCF结合位点位于裂解控制区和潜伏控制区的RBP-JK位点附近。由于RBP-JK是KSHV立即早期蛋白RTA和潜伏期维持蛋白LANA的主要靶点，我们将探索这些蛋白(如RBP-JK、RTA、K8和LANA)如何与CTGF-内聚功能相互作用并调节其功能。我们还将研究宿主固有防御蛋白在调节病毒染色质组装中的作用。最后，我们将探讨LANA和KSHV感染对病毒和宿主染色体结构和表观遗传学的影响：修饰。这些目标将与该计划项目的项目1和2协同工作，并提供对KSHV感染早期阶段和建立KSHV潜伏期期间染色质控制机制的分子和基因组范围的分析。

PROJECT SUMMARY (See instructions): KSHV is a human gammaherpesvirus that is the causative agent of Kaposi's sarcoma (KS), and tightly associated with pleural effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). Establishment of latent infection in B-lymphocytes and persistent infection in endothelial cells is thought to be a major driving force for KSHV-associated disease. Establishment of latent infection requires the formation of a stable circular minichromosome that expresses a limited set of viral genes. The mechanisms that establish minichromosome formation and restrict gene expression to the latency class are not well understood. Our previously published studies indicate that chromatin boundary factors, like CTCF, organize viral chromosome structure and histone modification patterns important for genome stability and restricted gene expression. CTCF interacts with cohesins (e.g. SMCl, SMC3, Rad21) to form higher order DNA conformations that are important for chromosome transmission during cell division and for coordinated transcription regulation. Recent studies from our group revealed that CTCF-cohesins mediate Interactions between the latent and lytic control regions of KSHV genomes in latently infected PEL cells. New preliminary data indicate that lytic immediate early genes are coordinately regulated through a chromatin structure involving CTCF and cohesins, and that cohesins are required for suppression of lytic gene transcription. Furthermore, CTCF binding sites are located in close proximity to RBP-jK sites at the lytic and latent control regions. Since RBP-jK is a primary target of KSHV immediate early protein Rta and latency maintenance protein LANA, we will explore how these proteins (e.g. RBP-jK, Rta, K8, and LANA) may interact with arid regulate CTGF-cohesion function. We will also investigate the role of host intrinsic defense proteins in regulating viral chromatin assembly. Finally, we will explore the role of LANA and KSHV infection on viral and host chromosome structure and epigenetic: modifications. These aims will synergize with projects 1 & 2 of this program project, and provide both molecular and genome-wide analyses of chromatin control mechanisms during the early stages of KSHV infection and in the establishment of KSHV latency.