Tegument ICP0 and HSV Entry

描述（由申请人提供）：单纯疱疹病毒（HSV）是一种常见和重要的人类病原体，可引起终身潜伏感染和多种疾病，从唇疱疹和生殖器病变到失明和致命的脑炎。当病毒包膜与细胞膜融合时，单纯疱疹病毒被膜层内的蛋白质在进入细胞时被释放到细胞中。然后，HSV衣壳和衣壳相关被膜蛋白利用宿主细胞骨架机制运输到细胞核。我们最近表明，传入的HSV在穿透后的步骤中使用26S蛋白酶体机制来启动感染。ICP0是一种由感染细胞合成的多功能病毒蛋白，具有立即早期动力学。ICP0有一个锌结合环指基序，赋予E3泛素连接酶活性。ICP0也是病毒粒子被膜的一个组成部分，并与感染病毒的病毒粒子一起被带入细胞。被皮ICP0的功能作用在很大程度上尚未确定。我们的初步研究表明，ICP0在蛋白酶体依赖性病毒进入中起作用。该项目的长期目标是了解HSV在感染的早期阶段用于进入宿主细胞核的病毒-细胞相互作用。本提案的目的是确定被膜ICP0在HSV感染早期事件前的命运和功能。我们的中心假设是被皮ICP0调节蛋白酶体依赖的病毒核衣壳从细胞外周到细胞核的传递。提出了两个目标。在Specific Aim 1中，将定义受ICP0影响的进入过程中的精确步骤。还将分析ICP0的环指结构域在蛋白酶体依赖性衣壳运输中的作用。在特异性目标2中，将确定被皮ICP0的稳定性和亚细胞定位。蛋白酶体和ICP0功能域在这些过程中的作用将被定义。分子、生物化学和细胞生物学方法的结合将被用来实现这些目标。这些研究将扩大我们对衣壳靶向细胞核启动生产性感染机制的理解。通过确定病毒进入宿主的新要求，结果将增加我们对HSV感染早期步骤的认识，并揭示新的治疗干预目标。公共卫生相关性：单纯疱疹病毒是感染的常见原因，可引起严重并发症，如新生儿感染和致命性脑炎。本研究的目的是通过研究病毒与宿主细胞的相互作用来确定单纯疱疹病毒如何在人类中引发感染。对病毒进入过程的更深入了解可能有助于开发预防疱疹感染的新方法。

DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) is a common and significant human pathogen that causes lifelong latent infection and a variety of diseases, ranging from cold sores and genital lesions to blindness and fatal encephalitis. Proteins within the tegument layer of HSV are released into the cell upon entry when the viral envelope fuses with the cell membrane. HSV capsids and capsid-associated tegument proteins then utilize the host cytoskeletal machinery for transport to the nucleus. We recently showed that incoming HSV employs the 26S proteasome machinery at a postpenetration step to initiate infection. ICP0 is a multi-functional viral protein that is synthesized by the infected cell with immediate-early kinetics. ICP0 has a zinc binding RING finger motif that confers E3 ubiquitin ligase activity. ICP0 is also a component of the virion tegument and is brought into the cell with the infecting viral particle. The functional role of tegument ICP0 has been largely undetermined. Our preliminary studies indicate a role for ICP0 in proteasome-dependent viral entry. The long-term goal of this project is to understand the virus-cell interactions that HSV uses to gain access to the host cell nucleus during the earliest stages of infection. The objective of this proposal is to determine the fate and function of tegument ICP0 in the context of pre-immediate early events in HSV infection. Our central hypothesis is that tegument ICP0 modulates the proteasome-dependent delivery of the viral nucleocapsid from the cell periphery to the nucleus. Two aims are proposed. In Specific Aim 1, the precise step in the entry process that is affected by ICP0 will be defined. The role of the RING finger domain of ICP0 in the proteasome-dependent transport of capsids will also be analyzed. In Specific Aim 2, the stability and subcellular localization of tegument ICP0 will be determined. The roles of the proteasome and of ICP0 functional domains in these processes will be defined. A combination of molecular, biochemical and cell biological approaches will be used to achieve these goals. These studies will widen our understanding of the mechanism for capsid targeting to the nucleus to initiate productive infection. By identifying new requirements for virus entry into the host, the results will increase our knowledge of the early steps of HSV infection and reveal targets for novel therapeutic intervention. PUBLIC HEALTH RELEVANCE: Herpes simplex virus is a common cause of infections and can cause serious complications such as neonatal infections and fatal encephalitis. The purpose of this research is to determine how the herpes simplex virus initiates infection in humans by studying the virus interaction with host cells. Greater understanding of the virus entry process may help to develop novel approaches to prevent herpes infections.