Chromatin Regulation of KSHV Primary Infection

项目摘要 (See说明）： KSHV是一种人类γ疱疹病毒，是卡波西肉瘤（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。在B淋巴细胞中建立潜伏感染和在内皮细胞中建立持续感染被认为是KSHV相关疾病的主要驱动力。潜伏感染的建立需要形成一个稳定的环状微型染色体，表达一组有限的病毒基因。建立微型染色体形成和限制基因表达的潜伏类的机制还没有很好的理解。我们以前发表的研究表明，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重要的基因组稳定性和限制基因表达。CTCF与粘着蛋白（例如SMC 1、SMC 3、Rad 21）相互作用以形成对于细胞分裂期间的染色体传递和对于协调转录调节重要的高阶DNA构象。我们小组最近的研究表明，CTCF-粘附蛋白介导潜伏感染的PEL细胞中KSHV基因组的潜伏和裂解控制区之间的相互作用。新的初步数据表明，裂解立即早期基因协调调节，通过染色质结构，涉及CTCF和cohesins，和cohesins所需的抑制裂解基因转录。此外，CTCF结合位点位于裂解和潜伏控制区的RBP-jK位点附近。由于RBP-jK是KSHV立即早期蛋白Rta和潜伏期维持蛋白拉娜的主要靶标，因此我们将探索这些蛋白（例如RBP-jK、Rta、K8和拉娜）如何与CTGF-凝聚功能相互作用并调节CTGF-凝聚功能。我们也将研究宿主内在防御蛋白在调节病毒染色质组装中的作用。最后，我们将探讨拉娜和KSHV感染对病毒和宿主染色体结构和表观遗传修饰的作用。这些目标将与该项目的项目1和2协同作用，并在KSHV感染的早期阶段和建立KSHV潜伏期期间提供染色质控制机制的分子和全基因组分析。

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.