Role of HCMV Glycoprotein in Viral Biogenesis

描述（由申请人提供）：人巨细胞病毒（HCMV）是一种 普遍存在的病原体，是免疫功能低下患者的主要病因 个体，如艾滋病和骨髓移植患者。HCMV是 也是最常见的先天性病毒感染， 儿童传染性中枢神经系统发育不良。尽管临床上的重要性， 这种病毒病原体，关于分子和细胞基础知之甚少， HCMV在感染细胞中的组装。目前的HCMV模型表明， 病毒衣壳转运到细胞质后， trans-Golgi网络（TGN）和相关的内体区室， 布满包膜糖蛋白的细胞膜。正确的定位和 包膜糖蛋白的加工是生产 传染性病毒了解HCMV生物发生的关键是确定 定位成熟糖蛋白的细胞和分子机制 病毒装配的隔室。最近的研究表明， HCMV主要包膜糖蛋白gB，一种必需的疱疹病毒糖蛋白， 结果表明：1）HCMV gB定位于TGN，并在TGN的顶面分布 在极化细胞（HCMV释放的表面）中，2）TGN定位是 由gB与细胞连接器PACS- 1的相互作用介导，和3） gB的弗林蛋白酶依赖性切割的抑制引起gB的错分选， 未加工的糖蛋白，加上一个戏剧性的块在生产 传染性病毒。 本申请的目的是确定gB在HCMV组装中的作用。 为了实现这一目标，我们将致力于四个具体目标：1）确定 顺式作用分选信号引导gB与PACS-I结合，并且gB 基序和结构域的必要和足够的指导TGN定位， 2）确定PACS-1介导的gB定位的机制， TGN，以及这种相互作用对生产的要求， 感染性HCMV，3）研究弗林蛋白酶依赖性加工的作用， gB在病毒糖蛋白的TGN定位和病毒装配中，4） 确定gB TGN定位、内体分选和 通过分析HCMV重组体在病毒装配中的弗林蛋白酶依赖性蛋白水解 表达在这些过程中有缺陷的gB基因。这些研究将 增加我们对HCMV gB细胞生物学的了解， 病毒组装的分子机制，这将使发展 治疗病毒性疾病的新疗法。

DESCRIPTION (provided by applicant): Human cytomegalovirus (HCMV) is a ubiquitous pathogen that is a major cause of disease in immunocompromised individuals, such as AIDS and bone marrow transplantation patients. HCMV is also the most common congenital viral infection and is the leading cause of infectious CNS maldevelopment in children. Despite the clinical importance of this viral pathogen, little is known regarding the molecular and cellular basis of HCMV assembly in infected cells. Current models of HCMV suggest that following transport of viral capsids to the cytoplasm, they are enveloped at the trans-Golgi Network (TGN) and associated endosomal compartments by membranes studded with envelope glycoproteins. Correct localization and processing of the envelope glycoproteins is required for the production of infectious virus. Key to understanding HCMV biogenesis is a determination of the cellular and molecular mechanisms that localize the mature glycoproteins to the compartment(s) of viral assembly. Recent studies of the cell biology of the major HCMV envelope glycoprotein gB, an essential herpes virus glycoprotein, show that: 1) HCMV gB is localized to the TGN and sorts to the apical surface in polarized cells (the surface of HCMV release), 2) TGN localization is mediated by interaction of gB with the cellular connector, PACS- 1, and 3) inhibition of furin-dependent cleavage of gB causes missorting of the unprocessed glycoprotein and is coupled with a dramatic block in the production of infectious virus. The goal of this application is to determine the role of gB in HCMV assembly. To achieve this goal, we will address four specific aims: 1) identify the cis-acting sorting signals that direct binding of gB to PACS-l and the gB motifs and domains necessary and sufficient to direct the TGN localization and sorting, 2) determine the mechanism(s) of PACS-1-mediated localization of gB to the TGN, and the requirement of this interaction for the production of infectious HCMV, 3) investigate the role of the furin-dependent processing of gB in both TGN localization of the viral glycoprotein and in virus assembly, 4) determine the role of gB TGN localization, endosome sorting, and furin-dependent proteolysis in virus assembly by analysis of HCMV recombinants expressing gB genes defective in these processes. Together, these studies will increase our knowledge of the cell biology of HCMV gB and provide insight into the molecular mechanisms of viral assembly that will enable development of novel therapeutics to treat viral disease.