Mechanisms of KSHV post-transcriptional gene regulation

描述（由申请人提供）：病毒使用广泛的分子机制来促进其自身基因在受感染宿主细胞的复杂环境中表达。最近的进展表明，细胞RNA衰变途径的病毒调节比以前认识到的更常见。例如，卡波西肉瘤相关疱疹病毒（KSHV）中的几个因子已被证明可调节宿主或病毒RNA周转率。在这个提议中，KSHV ORF 57蛋白在病毒转录物稳定性中的作用被检查。ORF57是一种对病毒复制至关重要的裂解相蛋白，据报道它影响mRNA生物合成中的各种核事件，但其分子机制仍不清楚。该提案中的实验旨在验证ORF57与核RNA结合并保护它们免受细胞RNA衰变途径的假设。具体而言，本文所述的研究将通过检查1）ORF57对病毒mRNA的核稳定性的影响，2）RNA结合和ORF57功能之间的关系，以及3）ORF57 RNA结合和稳定性活性在病毒裂解感染背景下的作用，阐明ORF57核功能的分子机制。了解ORF57的分子机制是了解KSHV生物学的基础，KSHV是卡波西肉瘤，原发性渗出性淋巴瘤（PEL）和某些类型的多中心Castleman病（MCD）的病原体。对ORF57分子机制的认识可能会导致新的治疗方法，并加强对控制肿瘤发生重要途径的认识。因此，通过揭示ORF57功能的机制，这些研究将为这种重要的人类病原体及其人类宿主细胞的生物学提供分子见解。

DESCRIPTION (provided by applicant): Viruses use a wide spectrum of molecular mechanisms to favor their own gene expression in the complex environment of an infected host cell. Recent advances suggest that viral regulation of cellular RNA decay pathways is more common than previously appreciated. For example, several factors in the Kaposi's sarcoma-associated herpesvirus (KSHV) have been demonstrated to regulate host or viral RNA turnover rates. In this proposal, a role for the KSHV ORF57 protein in viral transcript stability is examined. ORF57 is a lytic phase protein that is essential for viral replication and has been reported to affect a wide variety of nuclear events in mRNA biogenesis, but its molecular mechanisms remain unknown. The experiments in this proposal are designed to test the hypothesis that ORF57 binds to nuclear RNAs and protects them from cellular RNA decay pathways. Specifically, the studies described here will elucidate the molecular mechanisms of ORF57 nuclear function by examining 1) the effects of ORF57 on nuclear stability of viral mRNAs, 2) the relationship between RNA binding and ORF57 function, and 3) the roles of ORF57 RNA-binding and stability activities in the context of viral lytic infection. Understanding the molecular mechanism of ORF57 is fundamental to understanding the biology of KSHV, the causative agent for Kaposi's sarcoma, primary effusion lymphoma (PEL), and some types of multicentric Castleman's disease (MCD). An appreciation of ORF57 molecular mechanisms may lead to novel therapeutic approaches and bolster knowledge of the pathways important for controlling tumorigenesis. Thus, by revealing the mechanisms of ORF57 function, these studies will provide molecular insights into this important human pathogen and into the biology of its human host cells.