ACTIVATION OF KAPOSI SARCOMA-ASSOCIATED HERPES VIRUS

描述(摘自申请者摘要)：伽马疱疹病毒 卡波西肉瘤相关疱疹病毒(KSHV)或人类 人类疱疹病毒8(HHV8)可能是两种恶性肿瘤的病原体， 卡波西肉瘤(KS)和原发性渗出性淋巴瘤(PEL)，发生在 艾滋病患者。在这两个与KSHV相关的大多数细胞中 肿瘤病毒仍处于潜伏状态，但存在于细胞亚群中 KSHV被激活为裂解周期基因表达。申请者发现 一些KSHV基因是细胞趋化因子的同源物， 可能在病毒中发挥关键作用的细胞因子和抗凋亡因子 生物学在病毒基因表达的裂解阶段表达，在 KS活组织切片和来源于PEL的细胞系。作为开创性的线索 裂解循环激活的机制我们已经鉴定出一种KSHV 被称为KSHV/RTA的基因产物，部分编码在ORF50中，激活 包括vIL6在内的溶解周期基因在PEL细胞中的表达。他们的全球 目的是了解ORF50基因产物在开关中的作用 B细胞潜伏期与溶血周期基因表达的关系 微血管内皮细胞。调查人员将对事件进行分析 KSHV/RTA表达下游决定ORF50/RTA是否有活性 来激活整个病毒裂解循环程序。利用核酶抑制 申请者将了解ORF50是否对病毒的重新激活至关重要。 他们将研究KSHV/RTA的作用机制，了解它是否作用 直接，通过结合下游基因启动子中的DNA，或间接 通过其他蛋白质识别DNA。他们将探索它是否会自动刺激 它自己的表情。他们将描绘出导致激活的途径 ORF50表达，最终了解这种激活是否伴随着 与ORF50启动子结合的细胞蛋白的获得或丢失 吉恩。他们将确定KSHV/ORF50产品是否起到了激活作用 在造血细胞和血管内皮细胞新生感染中的作用或仅 在裂解周期重新激活过程中起作用。拟议的实验采用了一种 结合生物学、分子、遗传学和生化方法进行研究 KSHV生命周期的一个中心特征。这些研究应该提供洞察力 探讨KSHV相关疾病的分子发病机制及治本 关于控制致癌疱疹病毒基因表达的问题。

DESCRIPTION (Adapted from the Applicant's Abstract): The gammaherpesvirus variably known as Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus eight (HHV8) is the likely etiologic agent of two malignancies, Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), that occur in patients with AIDS. In the majority of cells of these two KSHV-associated tumors the virus remains in a latent state, but in a subpopulation of cells KSHV is activated into lytic cycle gene expression. The applicants have found that a number of KSHV genes that are homologues of cellular chemokines, cytokines and anti-apoptotic factors that likely play critical roles in virus biology are expressed during the lytic phase of viral gene expression both in KS biopsies and in cell lines derived from PEL. As a seminal clue to the mechanism of lytic cycle activation we have identified a KSHV immediate-early gene product termed KSHV/Rta, partially encoded in ORF50, that activates expression of lytic cycle genes including vIL6 in PEL cells. Their global objective is to understand the role of the ORF50 gene product in the switch between latency and lytic cycle gene expression both in B cells and in microvascular endothelial cells. The investigators will analyze the events downstream of KSHV/Rta expression to determine whether ORF50/Rta is competent to activate the entire viral lytic cycle program. Using ribozyme inhibition the applicants will learn whether ORF50 is essential for reactivation of the virus. They will study the mechanism of action of KSHV/Rta, learning whether it acts directly, by binding DNA in the promoters of downstream genes, or indirectly recognizing DNA via other proteins. They will explore whether it autostimulates its own expression. They will delineate the pathway leading to activation of ORF50 expression, ultimately learning whether this activation is accompanied by acquisition or loss of cellular proteins that bind to the promoter of the ORF50 gene. They will determine whether the KSHV/ORF50 product plays an activating role in de novo infection of hematopoietic and endothelial cells or only functions during lytic cycle reactivation. The proposed experiments employ a combination of biologic, molecular, genetic and biochemical approaches to study a central feature of the KSHV life cycle. The studies should provide insights into molecular pathogenesis of KSHV-associated disease and address fundamental questions about control of oncogenic herpesvirus gene expression.