Regulation and Action of APOBEC3G

APOBEC3G的监管和行动

• 批准号: 7414017
• 负责人: Warner C. Greene
• 金额: $ 52.12万
• 依托单位: J. DAVID GLADSTONE INSTITUTES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7414017
• 关键词: 5-bromo-4-chloro-3-indolyl beta-galactoside; Adverse effects; Affect; Amino Acids; Anti-Retroviral Agents; Antiviral Agents; Binding; Biological; Biological Assay; Biology; CD4 Positive T Lymphocytes; Catalytic Domain; Cell physiology; Cells; Clinical; Complex; Cytidine; Cytidine Deaminase; DNA; Deamination; Deoxycytidine; Detection; Development; Disruption; Dissection; Drug Delivery Systems; ES Cell Line; Enzymes; Eukaryotic Cell; Exhibits; Family member; Fire - disasters; Galactosidase; Gene Family; Genes; Genetic Transcription; Genome; Growth; HIV; HIV Budding; HIV Infections; HIV drug resistance; Human T-lymphotropic virus 1; Immune; Integration Host Factors; Interleukin-2; Introns; Laboratories; Malignant Neoplasms; Mammalian Cell; Manuscripts; Mediating; Messenger RNA; Mitogens; Molecular Weight; Monoclonal Antibody HuM291; Muromonab-CD3; Mus; Mutate; Mutation; Ovary; Pancreatic ribonuclease; Paper; Phytohemagglutinins; Preparation; Production; Proteins; RNA; RNA Editing; Range; Recruitment Activity; Regulation; Reporter Genes; Research Personnel; Rest; Retroviridae; Reverse Transcription; Ribonucleoproteins; SIV; Scientist; Seminal; Small Interfering RNA; T-Lymphocyte; Testing; Testis; Time; Tissue Stains; Tissues; Transcript; Transgenic Mice; Viral; Virion; Virus; acrosome stabilizing factor; analog; apoB mRNA editing catalytic subunit; apolipoprotein B mRNA editing enzyme; base; blocking factor; cytokine; fascinate; in vivo; insight; interest; member; monocyte; multicatalytic endopeptidase complex; mutant; novel; novel therapeutics; polypeptide; programs; receptor; reproductive; research study; vector; vif Gene Products; viral DNA; viral RNA

DESCRIPTION (provided by applicant): Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-1 like 3G (APOBEC3G, A3G) corresponds to a host-derived cytidine deaminase that displays potent anti-retroviral activity. When incorporated into budding HIV virions, the A3G enzyme massively mutates nascent HIV DNA produced during reverse transcription in the next target cell thereby halting HIV growth. HIV counters these effects of A3G through its Vif gene product, which promotes accelerated proteasome-mediated degradation and partially impaired de novo synthesis of A3G. The intracellular depletion of A3G makes the antiviral enzyme unavailable for incorporation into progeny virions. Our recent studies have unveiled a second antiviral action of A3G operating in resting CD4 T-cells. In these T-lymphocytes, cellular A3G functions as a highly active post-entry restriction factor blocking the growth of both wild type and deltaVif forms of HIV. Whether this "Vif-resistant" anti-HIV defense mediated by A3G involves cytidine deamination or a different mechanism is currently unknown. Further, the mechanism by which this post-entry restricting function of A3G is forfeited when T-cells are activated remains incompletely understood. Similarly, little is known about how host cells safeguard their own DNA from the mutagenic effects of A3G. Finally, it remains unknown whether A3G exerts other key functions beyond these antiviral effects. In Specific Aim 1, experiments will be performed to decipher how A3G and the closely related A3F and A3B antiviral enzymes are regulated in cells. In Specific Aim 2, the mechanism of A3G action as a post-entry restriction factor in resting CD4 T-cells, the range of viruses affected by this restriction, and potential similar functions of A3F will be delineated. Finally, in Specific Aim 3, studies will be conducted to assess whether A3G mediates important non-antiviral functions in mammalian cells. These experiments will involve the preparation and analysis of mice lacking the functional analogue of the A3G gene. Together, this program of proposed experimentation promises to enrich our understanding of the biology of A3G as well as the related A3F and A3B enzymes. With such understanding, new therapeutic strategies for inhibiting HIV growth could emerge.

描述（由申请人提供）：载脂蛋白B mRNA编辑酶，催化多肽-1如3G（APOBEC3G，A3G）对应于宿主来源的胞苷脱氨酶，显示出有效的抗逆转录病毒活性。当掺入出芽的 HIV 病毒体时，A3G 酶会大量突变下一个靶细胞中逆转录过程中产生的新生 HIV DNA，从而阻止 HIV 生长。 HIV 通过其 Vif 基因产物对抗 A3G 的这些影响，该产物促进加速蛋白酶体介导的降解并部分损害 A3G 的从头合成。 A3G 的细胞内耗竭使得抗病毒酶无法掺入子代病毒粒子中。我们最近的研究揭示了 A3G 在静息 CD4 T 细胞中发挥的第二种抗病毒作用。在这些 T 淋巴细胞中，细胞 A3G 作为高度活跃的进入后限制因子发挥作用，阻止野生型和 deltaVif 形式的 HIV 的生长。这种由 A3G 介导的“Vif 抗性”抗 HIV 防御是否涉及胞苷脱氨作用或不同的机制目前尚不清楚。此外，当 T 细胞被激活时，A3G 的进入后限制功能丧失的机制仍不完全清楚。同样，我们对宿主细胞如何保护自身 DNA 免受 A3G 的诱变作用知之甚少。最后，除了这些抗病毒作用之外，A3G 是否还发挥其他关键功能仍不清楚。在具体目标 1 中，将进行实验来破译 A3G 以及密切相关的 A3F 和 A3B 抗病毒酶在细胞中的调节方式。在具体目标 2 中，将描述 A3G 作为静息 CD4 T 细胞进入后限制因子的作用机制、受此限制影响的病毒范围以及 A3F 的潜在类似功能。最后，在具体目标 3 中，将进行研究以评估 A3G 是否介导哺乳动物细胞中重要的非抗病毒功能。这些实验将涉及缺乏 A3G 基因功能类似物的小鼠的制备和分析。总之，这个拟议的实验计划有望丰富我们对 A3G 以及相关 A3F 和 A3B 酶生物学的理解。有了这样的认识，抑制艾滋病毒生长的新治疗策略可能就会出现。