Effect of HIV-1 Vpr on Basic Cellular Functions

HIV-1 Vpr 对基本细胞功能的影响

• 批准号: 6450921
• 负责人: RICHARD YUQI ZHAO
• 金额: $ 24.85万
• 依托单位: LURIE CHILDREN'S HOSPITAL OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6450921
• 关键词: HIV infections; Schizosaccharomyces pombe; cell component structure /function; cell cycle; gene expression; host organism interaction; human immunodeficiency virus 1; immunoprecipitation; intermolecular interaction; membrane transport proteins; molecular site; phosphoprotein phosphatase; phosphorylation; posttranslational modifications; proteasome; protein localization; protein structure function; proteolysis; radiotracer; reporter genes; transcription factor; virus genetics; virus infection mechanism; virus protein; western blottings; yeast two hybrid system

HIV-1 Vpr plays a pivotal role in viral pathogenesis, as its functions are being linked to nuclear transport of visual pre-integration complex, viral replication and suppression of human immune function. However, little is known about the molecular mechanisms underlying these effects. In this proposal, we will focus on studying two related effects of Bpr on cell cycle G2/M control and proteolysis, which will help us to further understand the molecular basis of these viral effects on the host cellular functions. We have successfully accomplished three proposed Specific Aims. 1) to define the functional domains of Vpr responsible for nuclear localization, G2 arrest and cell killing, 2) to identify the cellular pathways affected by Vpr when it interrupts the cell cycle, and 3) to investigate the specific roles of PP2A in Vpr-induced G2 arrest. We showed that Vpr activities in fission yeast cells are very similar to those in mammalian cells. We also found that Vpr does not induce G2 arrest through the two classic DNA damage or replication checkpoints but instead through a PP2A-dependent novel regulatory pathway. In addition, we have identified a number of genes which when over- expressed suppress the G2 arrest and nuclear localization of Vpr, and these suppressions suggest a new role for Vpr in the regulation of proteolysis. For the proposed studies, we hypothesize that Vpr induces G2 arrest through a novel PP2A-dependent regulatory pathway(s), and Vpr affects proteolysis by interaction with the proteasome on the nuclear periphery. Three new specific aims are proposed to test these hypotheses. 1) To define and characterize the cellular components of the new PP2A- dependent regulatory pathway by which Vpr induces G2 arrest. 2) To investigate the potential interaction of Vpr with the proteasome at the nuclear periphery. 3) To evaluate the possible role of pr-proteasome interaction in the regulation of proteolysis including a relationship between Vpr-induced G2 arrest and proteasome activity. These proposed studies will be confirmed in human cells and provide important new insights into fundamental aspects of the Vpr's effects on these two basic cellular functions.

HIV-1VPR在病毒发病机制中起着关键作用，因为其功能与核转运、病毒复制和抑制人类免疫功能有关。然而，人们对这些效应背后的分子机制知之甚少。在本方案中，我们将重点研究BPR对细胞周期G2/M调控和蛋白降解的两个相关影响，这将有助于我们进一步了解这些病毒对宿主细胞功能影响的分子基础。我们成功地实现了三个提出的具体目标。1)确定VPR在细胞核定位、G2期停滞和细胞杀伤中的功能域；2)确定VPR阻断细胞周期时影响细胞周期的途径；3)研究PP2A在VPR诱导的G2期停滞中的具体作用。我们发现裂解酵母细胞中的VPR活性与哺乳动物细胞中的VPR活性非常相似。我们还发现，VPR并不是通过两个经典的DNA损伤或复制检查点来诱导G2期停滞，而是通过一种依赖于PP2A的新的调控途径。此外，我们还发现了一些基因，它们在过度表达时抑制了VPR的G2期停滞和核定位，这些抑制表明VPR在蛋白降解调节中发挥了新的作用。在所提出的研究中，我们假设vpr通过一种新的PP2A依赖的调控途径(S)诱导G2期停滞，vpr通过与核外周蛋白酶体相互作用影响蛋白降解。为了检验这些假设，本文提出了三个新的具体目标。1)确定和表征新的依赖PP2A的调控途径的细胞成分，VPR通过该途径诱导G2期停滞。2)研究VPR与核周蛋白酶体的潜在相互作用。3)探讨PR-蛋白酶体相互作用在蛋白降解调控中的可能作用，包括VPR诱导的G2期停滞与蛋白酶体活性的关系。这些拟议的研究将在人类细胞中得到证实，并为VPR对这两种基本细胞功能的影响的基本方面提供重要的新见解。