Dissecting the Functional Domains of Infected Cell Protein 0 of Herpes Simplex Virus 1

 描述(申请人提供)：单纯疱疹病毒1型(HSV-1)是一种嗜神经病毒，感染世界70%以上的成年人。它在三叉神经节中建立了一个终生潜伏期，并零星地重新激活，在幼稚的人群中传播。它会引起广泛的临床表现，如口疮、生殖器溃疡、角膜炎和致命的疱疹脑炎。感染细胞蛋白0(ICP0)是一种即刻早期蛋白，是裂解感染和潜伏期重新激活的关键调节因子，在对抗宿主抗病毒防御中发挥着至关重要的作用。ICP0含有一个E3泛素连接酶，该酶介导多种宿主限制性因子的蛋白酶体降解，从而增强病毒基因的表达。它还与许多细胞蛋白相互作用，以调节参与抗病毒防御的各种细胞途径。定位ICP0的多功能 在ICP0的不同领域中，必须相互协调才能协调一致地进行健壮的感染。我们实验室和其他几个实验室的结果表明，在HSV-1感染的拉锯战中，动态核结构域10(ND10)结构与ICP0密切相互作用。一方面，ND10与病毒DNA结合，进行基因抑制。另一方面，ICP0与ND10融合并降解其组织蛋白PML(早幼粒细胞白血病)，以分散ND10小体，释放抑制。我们以前报道过ICP0-ND10的相互作用是一个动态的过程，包括黏附、融合和保持的连续步骤，而特定的ICP0结构域参与了这些动态步骤的忠实执行。本申请的总体目标是剖析ICP0对ND10融合过程和E3泛素连接酶活性至关重要的功能结构域，并描述ICP0结构域在对抗宿主防御中的协调作用。我们计划构建ICP0突变病毒，以确定功能结构域，表征不同结构域之间的协调，并分离与这些特定结构域相互作用的蛋白质。我们打算在这项拨款申请中追求以下具体目标：(I)描绘分子 ND10融合过程的基础；(Ii)研究ICP0 E3泛素连接酶的调控机制。这些研究与了解HSV-1引起的传染病的使命高度相关。这些研究的结果将极大地促进我们对HSV-1感染的启动以及宿主防御的分子机制的了解。这项研究有望对开发新的抗疱疹疗法和了解细胞防御DNA病毒的机制产生重大影响。

 DESCRIPTION (provided by applicant): Herpes simplex virus 1 (HSV-1) is a neurotropic virus that infects over 70% of the world adult population. It establishes a lifelong latency in trigemina ganglia and reactivates sporadically to spread to naïve population at their young age. It causes a wide range of clinical manifestations such as cold sores, genital ulceration, keratitis, and the deadly herpes encephalitis. Infected cell protein no. 0 (ICP0), an immediate early protein that is a key regulator for both lytic infection and latency reactivation, plays a vital role in the counteractions against host anti-viral defenses. ICP0 contains an E3 ubiquitin ligase, which mediates proteasomal degradation of several host restrictive factors and therefore enhance viral gene expression. It also interacts with numerous cellular proteins in order to regulate a diverse array of cell pathways participating in anti-viral defenses. The multiple functions of ICP0 located in different domains of ICP0 must coordinate with each other to orchestrate a robust infection. Results from our lab and several other labs have shown that a dynamic nuclear domain 10 (ND10) structure undertakes a close interplay with ICP0 in the tug-of-war of HSV-1 infection. On one hand, ND10 converges at viral DNA for gene repression. On the other hand, ICP0 merges with ND10 and degrades its organizer protein PML (promyelocytic leukemia) in order to disperse ND10 bodies and release the repression. We have previously reported that ICP0-ND10 interaction is a dynamic process that includes sequential steps of adhesion, fusion and retention, and specific ICP0 domains are involved in the faithful execution of these dynamic steps. The overall objective of the present application is to dissect the functional domains of ICP0 that are important for ND10 fusion process and E3 ubiquitin ligase activity, and to delineate ICP0 domain coordination in its counteractions against the host defense. We plan to construct ICP0 mutant viruses to identify functional domains, to characterize the coordination among different domains, and to isolate proteins interacting to these specific domains. We intend to pursue the following specific aims in this grant proposal: (i) to delineate the molecular basis of ND10 fusion process and (ii) to characterize the regulatory mechanisms of ICP0 E3 ubiquitin ligase. These studies are highly relevant to the mission of understanding infectious diseases caused by HSV-1. The outcomes of these proposed studies will greatly advance our knowledge of the initiation of HSV-1 infection, as well as the molecular mechanisms of host defenses. This study is expected to have a significant impact in developing new anti-herpes therapies and in understanding cellular defense mechanisms against DNA viruses.