Analysis of the mechanism of HCMV cytoplasmic envelopment

项目摘要 尽管人巨细胞病毒（HCMV）基本上无症状，但可导致严重甚至致命的疾病 在易感个体的子集中的疾病。虽然在理解基本的 HCMV复制的各个阶段，缺乏对许多这些过程的详细描述。特别感兴趣的 在这个建议中是细胞质的表达。为了提供一个分子描述的事件相关的 对于细胞质的表达，重要的是要确定涉及的因子，包括病毒和细胞。以前的工作 已经鉴定出UL 71是一种可能介导膜断裂的抑制因子，因为病毒缺乏 UL 71被困在萌芽的各个阶段。尚不清楚UL 71本身是否足以促进 或者如果它需要其他病毒和/或细胞因子。许多病毒利用细胞机器，称为 转运所需的内体分选复合物（ESCRT）作为转运过程的一部分。而 HCMV不需要早期ESCRT-I复合物，但需要晚期ESCRT Vps 4。的作用 ESCRT-III复合物是膜变形和断裂促进剂的主要驱动力， 被调查了了解ESCRT-III在感染过程中的作用（如果有的话）对于提供一个 细胞质修饰的详细描述。我们假设UL 71招募ESCRT-III和Vps 4， 介导出芽的HCMV衣壳的断裂。为了支持这一假设，UL 71和 VPS 4已经被报道。本实验将研究是否需要ESCRT-III亚基 HCMV复制，如果是，在什么阶段。他们会调查UL 71与 ESCRT-III和定义UL 71-Vps 4相互作用的功能，以及确定UL 71上重要的区域 功能。这些研究将进一步加深我们对细胞因子在HCMV感染中作用的认识 感染和潜在地鉴定病毒复制可以靶向的新方式。综上所述各项 这些研究将为深入了解HCMV细胞质增殖的机制奠定基础。

Project Summary Although largely asymptomatic, human cytomegalovirus (HCMV) can cause severe and even fatal disease in a subset of susceptible individuals. While great progress has been made in understanding essential stages of HCMV replication, a detailed description of many of these processes is lacking. Of particular interest in this proposal is cytoplasmic envelopment. To provide a molecular description of the events associated with cytoplasmic envelopment, it is important to identify the factors involved, both viral and cellular. Previous work has identified UL71 as an envelopment factor that potentially mediates membrane scission, as viruses lacking UL71 are trapped at various stages of budding. It is not known whether UL71 is sufficient itself for promoting scission or if it requires other viral and/or cellular factors. Many viruses utilize cellular machinery known as the endosomal sorting complexes required for transport (ESCRTs) as part of the envelopment process. While HCMV does not require the early ESCRT-I complex, it does require the late ESCRT Vps4. The role of the ESCRT-III complex, which is the major driver of membrane deformation and scission promoter, has not yet been investigated. Understanding the role, if any, for ESCRT-III during infection is essential for providing a detailed description of cytoplasmic envelopment. We hypothesize that UL71 recruits ESCRT-III and Vps4 to mediate scission of budding HCMV capsids. In support of this hypothesis, an interaction between UL71 and Vps4 has been reported. The experiments in this proposal will investigate if ESCRT-III subunits are required for HCMV replication, and if so at what stage. They will investigate the relationship, if any, between UL71 and ESCRT-III and define a function for the UL71-Vps4 interaction, as well as identify regions on UL71 important for function. These studies will further our understanding of the contribution of cellular factors to HCMV infection and potentially identify novel ways in which viral replication can be targeted. Taken together, these studies will lay the foundation for a mechanistic understanding of HCMV cytoplasmic envelopment.