Viral and cellular gene regulation during lytic KSHV replication

描述(由申请人提供)：这项申请的广泛、长期目标是了解卡波西肉瘤相关疱疹病毒(KSHV/HHV-8)的调节蛋白如何在裂解复制过程中控制病毒和细胞的基因表达。裂解基因产物可能在KSHV的发病机制中起作用，有助于KSHV感染细胞和邻近细胞的增殖、存活和避免免疫反应。因此，了解裂解基因表达的调节机制与KSHV相关的致病机制有关，KSHV仍然是发病率和死亡率的重要原因，特别是在艾滋病毒和KSHV感染率较高的地区。KSHV的ORF57蛋白在KSHV复制早期表达，是疱疹病毒蛋白家族的成员，在疱疹病毒复制中起重要作用。ORF57具有独特的调控特性，在转录后增强许多无内含子基因的表达。此外，ORF57增强了特定细胞基因的表达。ORF57可能通过与mRNA的物理结合以及调节其稳定性和核输出来发挥其许多作用。ORF57影响RNA加工的机制以及其作用的特异性是如何确定的，目前仍不清楚。因此，我们提出了三个综合目标来研究ORF57在KSHV生物学中的作用。在第一个目标中，我们将定义ORF57与mRNA结合的机制以及ORF57的特异性是如何确定的。在第二个目标中，我们将确定对ORF57功能重要的主要细胞蛋白质，特别是在核出口和mRNA加工方面。在第三个目标中，我们将利用分子遗传学来确定ORF57的哪些功能是KSHV复制所必需的。我们还将确定ORF57对血管内皮细胞和B淋巴细胞基因表达的特异性影响。KSHV是一种与癌症发展有关的病毒，特别是在免疫系统减弱的人中，例如艾滋病毒感染者。研究病毒是如何繁殖的，对于了解它是如何影响它感染的细胞并将它们转化为肿瘤细胞非常重要。这类研究还有可能确定针对该病毒的新药的靶点，这些新药可能有助于预防或治疗感染。

DESCRIPTION (provided by applicant): The broad, long term objective of this application is to understand how regulatory proteins of Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) control viral and cellular gene expression during lytic replication. Lytic gene products are likely to have a role in pathogenesis of KSHV, contributing to the ability of KSHV-infected cells and adjacent cells to proliferate, survive and avoid immune responses. Understanding the mechanisms by which lytic gene expression is regulated is therefore relevant to KSHV- related pathogenesis which continues to be a significant cause of morbidity and mortality, particularly in areas with high endemic rates of HIV and KSHV infection. The ORF57 protein of KSHV is expressed early during KSHV replication and is a member of a family of herpesvirus proteins that plays an essential role in herpesvirus replication. ORF57 has unique regulatory properties, post-transcriptionally enhancing expression of many intronless genes. In addition, ORF57 enhances expression of specific cell genes. ORF57 is likely to exert many of its effects by physically binding to mRNA and modulating its stability and nuclear export. Much remains unknown about the mechanisms by which ORF57 affects RNA processing and how its specificity of action is determined. We therefore propose three integrated aims to investigate the role of ORF57 in KSHV biology. In the first aim, we will define the mechanisms by which ORF57 binds mRNA and how ORF57 specificity is determined. In the second aim, we will identify the major cellular proteins that are important for ORF57 function, especially with regard to nuclear export and mRNA processing. In the third aim, we will determine which functions of ORF57 are essential for KSHV replication using molecular genetics. We will also determine the specific effects of ORF57 on gene expression in endothelial cells and B lymphocytes. KSHV is a virus that is linked to the development of cancer, particularly in those people who have weakened immune systems, such as those with HIV infection. Studying how the virus reproduces is important to understand how it affects the cells it infects and converts them to tumor cells. Such studies also have the potential to identify targets for new drugs against the virus that may help prevent or treat infection.