Retrovirus Entry and Virus Evolution

逆转录病毒进入和病毒进化

• 批准号: 6804506
• 负责人: Mark J Federspiel
• 金额: $ 25.55万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6804506
• 关键词: Retrovirus; Entry; Virus; Evolution

DESCRIPTION (provided by applicant): Retroviruses, which include many important pathogens of humans and animals, have become important research tools as benign gene delivery vectors, and have potential as therapeutic vectors for gene therapy. Whether pathogenic or therapeutic, the initial infection and subsequent dissemination of the virus depends on efficient entry of the retrovirus into host cells. While a detailed understanding of the mechanisms of viral entry has not been clearly defined for any retrovirus, all retroviruses share a common overall strategy for entry into cells. The initial step of retrovirus entry, the interaction between the viral surface glycoprotein (SU) and a cellular receptor, is complex, involving multiple, noncontiguous determinants in both proteins that specify receptor choice, binding affinity and the ability to trigger conformational changes in the viral glycoproteins. Despite the complexity of this interaction, retroviruses have the ability to evolve the structure of their envelope glycoproteins to use a different cellular protein as a receptor, often a protein that has no obvious homology to the original receptor, and retain efficient entry functions. How do retroviruses do this? Understanding this ability will provide valuable information for antiviral intervention and targeting gene delivery. We hypothesize that: (1) the envelope glycoproteins are organized into functional domains that allow changes to occur in receptor choice by mutation and/or recombination while maintaining a critical level of both receptor binding affinity and the ability to trigger glycoprotein conformational changes to initiate the fusion process; (2) multiple, noncontiguous receptor interaction determinants located in the SU hypervariable domains are required for binding affinity and to restrict or broaden receptor usage; (3) regions outside of the SU hypervariable domains will function to connect receptor binding to triggering the glycoprotein lock mechanism and will be conserved as the virus changes receptor usage. The homologous group of retroviruses, the subgroups A through E (A-E) avian leukosis viruses (ALV), provide a powerful model system to test these hypotheses by supplying highly related viruses that have evolved from a common ancestor to utilize different receptors. Specifically, we aim to:1. Genetically define functional regions/residues of the subgroup A-E ALV envelope glycoproteins important for receptor binding affinity. 2. Genetically define functional regions/residues of the subgroup A-E ALV glycoproteins important for the specificity of receptor usage. 3. Identify and characterize regions/residues in the ALV glycoproteins important for connecting receptor binding to triggering the conformational changes that initiate the fusion process. 4. Genetically define functional regions/residues of the ALV receptors necessary for binding affinity and triggering a conformational change in the ALV glycoproteins. 5. Test soluble forms of the ALV glycoproteins for the ability to produce crystals suitable for structural studies.

描述(申请人提供)：逆转录病毒，包括许多重要的人和动物的病原体，已成为良性基因传递载体的重要研究工具，并有潜力作为基因治疗的治疗载体。无论是致病性的还是治疗性的，病毒的最初感染和随后的传播都取决于逆转录病毒有效地进入宿主细胞。虽然对任何逆转录病毒的病毒进入机制的详细了解还没有明确定义，但所有的逆转录病毒都有一个共同的进入细胞的总体策略。逆转录病毒进入的第一步是病毒表面糖蛋白(SU)和细胞受体之间的相互作用，是复杂的，涉及两种蛋白质中的多个不连续的决定因素，这些决定因素指定了受体的选择、结合亲和力和触发病毒糖蛋白构象变化的能力。尽管这种相互作用很复杂，但逆转录病毒有能力进化其包膜糖蛋白的结构，以使用不同的细胞蛋白质作为受体，通常是一种与原始受体没有明显同源性的蛋白质，并保持有效的进入功能。逆转录病毒是如何做到这一点的？了解这种能力将为抗病毒干预和靶向基因传递提供有价值的信息。 我们假设：(1)包膜糖蛋白被组织成功能结构域，从而允许通过突变和/或重组改变受体选择，同时保持一个关键的受体结合亲和力和触发糖蛋白构象变化的能力以启动融合过程；(2)位于SU高变域的多个不连续的受体相互作用决定子对于结合亲和力和限制或扩大受体使用是必需的；(3)SU高变域之外的区域将起到连接受体结合和触发糖蛋白锁定机制的功能，并将随着病毒改变受体的使用而保守。逆转录病毒的同源组，A到E(A-E)亚组的禽白血病病毒(ALV)，通过提供从共同祖先进化而来的高度相关的病毒来利用不同的受体，提供了一个强大的模型系统来检验这些假说。具体地说，我们的目标是：1.从基因上确定对受体结合亲和力重要的A-E亚组ALV囊膜糖蛋白的功能区/残基。2.从基因上定义A-E亚组ALV糖蛋白的功能区/残基，这些功能区/残基对受体用途的特异性很重要。3.确定和鉴定ALV糖蛋白中重要的区域/残基，这些区域/残基对于连接受体结合和触发启动融合过程的构象变化非常重要。4.从基因上定义ALV受体的功能区/残基，以结合亲和力并触发ALV糖蛋白的构象变化。5.测试ALV糖蛋白的可溶性形式以产生适合于结构研究的晶体的能力。