PP2A AND THE INDUCTION OF G2 ARREST BY HIV1 VPR

PP2A 和 HIV1 VPR 诱导 G2 阻滞

• 批准号: 2887459
• 负责人: VICENTE PLANELLES
• 金额: $ 10.96万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2887459
• 关键词: T lymphocyte; cell cycle; chemical binding; enzyme activity; host organism interaction; human immunodeficiency virus 1; phosphoprotein phosphatase; protein structure function; tissue /cell culture; virus protein

DESCRIPTION: (Adapted from Investigator's Abstract) The Vpr gene of HIV-1 encodes a 96-amino-acid protein which plays multiple roles in the viral life cycle. Recently, the investigator and others have observed that Vpr inhibits proliferation of CD4 T-lymphocytes by inducing cell cycle arrest in G2. This viral function is conserved in evolution as other primate lentiviruses such as HIV-2, SIVmac, and SIVagm encode related genes which also induce G2 arrest. Induction of G2 arrest constitutes a novel observation with profound implications for the survival and immune function of CD4 T-lymphocytes. The investigator's preliminary investigations indicate that cells arrested in G2 by Vpr contain elevated levels of protein phosphatase 2A (PP2A) activity. Furthermore, immunoprecipitation experiments indicate that Vpr physically associates with PP2A. In view of the above observations he hypothesizes that the viral protein Vpr interacts with PP2A and this interaction causes up-regulation of PP2A. PP2A is known to influence the transition from G2 to mitosis by modulating the activity of Wee 1 and cdc25. Therefore, the potential effect of Vpr on PP2A activity provides a mechanistic explanation for the induction of G2 arrest by Vpr. The studies outlined in this application examine the interaction between viral Vpr and PP2A and further the understanding of mechanisms of cell cycle regulation. The Specific Aims of this application are: 1. To study how virally encoded HIV-1 Vpr activates PP2A and induces G2 arrest. Delivery of Vpr into the cell via viral infection can be accomplished by two routes: as a virion-bound protein and by de novo expression after viral integration. In addition to Vpr, HIV-1 encodes other accessory genes whose contributions to PP2A activation and G2 arrest are unknown. The experiments proposed in this Aim are designed to dissect various mechanistic aspects of the activation of cellular PP2A and induction of G2 arrest by virally expressed Vpr. 2. To characterize the interaction between HIV-1 Vpr and PP2A structurally and functionally. The investigator will identify particular subunit(s) of PP2A which physically interact with HIV-1 Vpr, and regions of PP2A and Vpr that are essential for binding. In addition, he proposes to study the functional consequences of this binding on the enzymatic activity of PP2A.

描述：(改编自《研究人员摘要》)HIV-1的vpr基因 编码一种96个氨基酸的蛋白质，在病毒生命中扮演多种角色 周而复始。最近，调查人员和其他人观察到VPR 通过诱导细胞周期停滞抑制CD4T淋巴细胞的增殖 G2。这种病毒功能在进化中与其他灵长类动物一样保守 慢病毒如HIV-2、SIVmac和SIVagm编码相关基因， 也会导致G2停滞。诱导G2被捕构成了一种新的 对生存和免疫功能有深刻影响的观察 CD4T淋巴细胞。调查员的初步调查 表明被VPR阻断在G2中的细胞含有升高的蛋白质水平 磷酸酶2A(PP2A)活性。此外，免疫沉淀 实验表明，VPR与PP2A在物理上存在联系。鉴于…… 根据上面的观察，他假设病毒蛋白vpr相互作用 与PP2A相互作用，这种相互作用导致PP2A上调。PP2A是已知的 通过调节细胞周期蛋白的活性来影响从G2向有丝分裂的转变 Wee 1和CDC25。因此，VPR对PP2A活性的潜在影响 为VPR诱导G2期停滞提供了机制解释。 本申请中概述的研究检查了 病毒VPR和PP2A及其对细胞周期机制的进一步认识 监管。这项申请的具体目的是：1.研究如何 病毒编码的HIV-1VPR激活PP2A并诱导G2期停滞。交付 VPR通过病毒感染进入细胞的途径有两条：AS 病毒粒子结合蛋白和病毒整合后的从头表达。 除了vpr，HIV-1还编码其他辅助基因，这些辅助基因对 对PP2A的激活和G2期的停滞尚不清楚。中提出的实验 这一目标旨在剖析 病毒表达对细胞内PP2A的激活和G2期细胞周期的影响 VPR。2.研究HIV-1vpr与PP2A的相互作用 在结构和功能上。调查员将确定具体的 与HIV-1 vpr物理相互作用的PP2A亚单位(S)，以及 PP2A和VPR是结合所必需的。此外，他还提议 研究这种结合对酶活性的功能影响 PP2A。