Vpr Revisited

重温 VPR

• 批准号: 7425735
• 负责人: Nathaniel R. Landau
• 金额: $ 42.28万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-15 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7425735
• 关键词: Accounting; Address; Affect; Affinity Chromatography; Antiviral Agents; Antiviral Response; Apoptosis; Binding; Biochemical; Biological; Blood Cells; CDT1 Gene; Cell Cycle Arrest; Cell Cycle Regulation; Cells; Complex; DNA; DNA Damage; DNA Repair; DNA Replication Damage; DNA Replication Factor; DNA biosynthesis; DNA-Binding Proteins; Development; Gel; Genomics; HIV; HIV-1; Immune; Immune response; Immune system; Integration Host Factors; Interferon Type I; Knowledge; Licensing Factor; M cell; Mediating; Molecular Machines; Natural Immunity; Nuclear; Pathogenesis; Pathogenicity; Pathway interactions; Phenotype; Physiological; Play; Protein Binding; Proteins; Proteomics; Public Health; Publishing; Purpose; Replication Licensing; Reporting; Retroviridae; Retrovirology; Role; STAT protein; STAT1 gene; STAT2 gene; Signal Pathway; Silver Staining; Subfamily lentivirinae; System; Testing; Viral Proteins; Virion; Virus; Virus Diseases; Virus Replication; Work; base; fascinate; follow-up; interest; protein degradation; repaired; response; symposium; tool; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): HIV-1 Vpr is a nuclear, virion packaged accessory protein encoded by all lentiviruses. SIV/HIV-2 encodes in addition, Vpx which maintains close sequence similarity. The hallmark of Vpr is that it induces G2/M cell cycle arrest. A key to understanding the role of Vpr/Vpx in virus replication and pathogenesis is the identification of the cellular proteins with which they interact. Several groups, including ours, recently reported the identification of a cellular complex with which Vpr and perhaps Vpx interact and through which they may function. The complex is an E3 ubiquitin ligase that consists of DDB1/DCAF1/CUL4A/ROC1. This complex regulates genomic DNA replication and damaged DNA repair by mediating the destruction of cellular proteins including the DNA replication-licensing factor CDT1, STAT1 and STAT2 and other, yet to be identified substrates. The identification of the interaction with the E3 ubiquitin ligase presents a unified explanation of how Vpr may mediate its effects and provides a framework to elucidate the role that Vpr plays in HIV-1 pathogenesis. Other viruses encode proteins that target this complex, using it as a means to induce degradation of STAT proteins to inhibit type-I interferon responses. We will determine whether Vpr acts through its interaction with the complex to arrest cells in G2, induce apoptosis and activate DNA damage signaling pathways. In addition, cellular proteins that bind to Vpx and to DCAF1 will be identified and characterized. Thirdly, the project will test they hypothesis that Vpr/Vpx play a role in dampening innate immune responses to the virus. Innate immunity has over the past several years become a topic of great interest. The project will determine whether Vpr/Vpx may constitute another such mechanism. PUBLIC HEALTH RELEVANCE Cells have mechanism by which they resist infection by viruses. These mechanism are of great interest because they provide new avenues for the development of antiviral drugs. Viruses have evolved means of escaping these so called innate immune mechanisms. HIV, for example produces a protein called virion infectivity factor( VIF) that inactivates one of the antiviral proteins that are produced by blood cells. In this project we will study an HIV protein called viral protein R (VPR) that may serve as yet another means by which the virus avoids the innate immune mechanisms. When a cell is infected with HIV, Vpr is produced and as we recently discovered, binds to a cellular protein called damaged DNA binding protein 1 (DDB1) in association with another protein called DCAF1. DCAF1/DDB1 is a molecular machine of the cell that destroys unwanted proteins. Our findings have shown that Vpr causes DDB1 to degrade certain cellular proteins and we hypothesize that at least one of these is an antiviral protein that the virus needs to destroy in order to replicate. The project will identify the targets of DDB1 and understand how these proteins work against the virus. In addition, Vpr seems to affect the normal function of the DCAF1/DDB1 complex and thereby disrupt functions in the cell such as DNA repair and DNA replication. The project will determine how this happens and how it affects replication of HIV.

描述（由申请人提供）：HIV-1 VPR是由所有慢病毒编码的核，病毒包装的辅助蛋白。 SIV/HIV-2还编码另外，VPX保持了近距离的相似性。 VPR的标志是它诱导了G2/M细胞周期停滞。了解VPR/VPX在病毒复制和发病机理中的作用的关键是鉴定其相互作用的细胞蛋白。几个组，包括我们的组，最近报道了VPR和VPX相互作用以及它们可能发挥作用的细胞复合物的鉴定。该复合物是由DDB1/DCAF1/CUL4A/ROC1组成的E3泛素连接酶。该复合物通过介导（包括DNA复制因子CDT1，STAT1和STAT2）以及其他尚未鉴定的底物来调节基因组DNA复制和受损DNA修复。与E3泛素连接酶相互作用的鉴定提供了一个统一的解释，即VPR如何介导其效果，并提供了一个框架来阐明VPR在HIV-1发病机理中的作用。其他病毒编码靶向该复合物的蛋白质，使用它作为诱导STAT蛋白降解以抑制I型干扰素反应的一种手段。我们将确定VPR是否通过与复合物与G2中的逮捕细胞相互作用来起作用，诱导凋亡并激活DNA损伤信号通路。另外，将鉴定和表征与VPX和DCAF1结合的细胞蛋白。第三，该项目将检验他们假设VPR/VPX在抑制对病毒的先天免疫反应中发挥作用。在过去的几年中，先天免疫已成为一个引起人们极大兴趣的话题。该项目将确定VPR/VPX是否可以构成另一种此类机制。公共卫生相关性细胞具有抗拒病毒感染的机制。这些机制引起了人们的关注，因为它们为抗病毒药的开发提供了新的途径。病毒已经发展出逃避这些所谓的先天免疫机制的手段。例如，HIV产生一种称为病毒感染因子（VIF）的蛋白质，该蛋白质使血细胞产生的一种抗病毒药蛋白之一失活。在这个项目中，我们将研究一种称为病毒蛋白R（VPR）的HIV蛋白，该蛋白可能是病毒避免先天免疫机制的另一种手段。当细胞感染HIV时，会产生VPR，并且正如我们最近发现的，与称为受损的DNA结合蛋白1（DDB1）的细胞蛋白结合，与另一种称为DCAF1的蛋白有关。 DCAF1/DDB1是破坏不需要蛋白质的单元的分子机。我们的发现表明，VPR会导致DDB1降解某些细胞蛋白，我们假设其中至少一种是一种抗病毒蛋白，该病毒需要破坏以复制。该项目将识别DDB1的靶标，并了解这些蛋白质如何针对病毒。此外，VPR似乎会影响DCAF1/DDB1复合物的正常功能，从而破坏细胞中的功能，例如DNA修复和DNA复制。该项目将确定这种情况的发生方式以及如何影响艾滋病毒的复制。