Analysis of the mechanism of HCMV cytoplasmic envelopment

项目摘要 尽管人类巨细胞病毒(HCMV)在很大程度上没有症状，但它可以引起严重甚至致命的 易感人群中的一种疾病。虽然在理解基本知识方面取得了很大进展 关于巨细胞病毒复制的各个阶段，缺乏对其中许多过程的详细描述。特别感兴趣的 在这个提议中是细胞质被膜。提供与以下事件相关的分子描述 对于细胞质被膜，重要的是确定所涉及的因素，包括病毒和细胞。以前的工作 已经确定UL71是一个潜在的介导膜断裂的包膜因子，因为病毒缺乏 UL71被困在萌芽的不同阶段。目前尚不清楚UL71本身是否足以推广 或者如果它需要其他病毒和/或细胞因素。许多病毒利用称为 运输所需的内体分选复合体(ESCRT)作为包膜过程的一部分。而当 HCMV不需要早期ESCRT-I复合体，它需要晚期ESCRT Vps4。美国政府的角色 ESCRT-III复合体是膜变形和裂解启动子的主要驱动力，但尚未 被调查过了。了解ESCRT-III在感染过程中的作用(如果有的话)对于提供 细胞质被膜的详细描述。我们假设UL71招募ESCRT-III和VPS4来 调节萌芽中的人巨细胞病毒衣壳的断裂。为了支持这一假设，UL71和UL71之间的相互作用 VPS4已被报道。该方案中的实验将调查是否需要ESCRT-III亚单位 用于复制人巨细胞病毒，如果是，在什么阶段。他们将调查UL71和UL71之间的关系 ESCRT-III，并定义UL71-Vps4相互作用的函数，以及识别UL71上的重要区域 对于函数。这些研究将进一步加深我们对细胞因素在人巨细胞病毒中的作用的理解。 并有可能确定针对病毒复制的新方法。这些加在一起， 这些研究将为从机制上理解人巨细胞病毒细胞质被膜奠定基础。

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.