Fusion triggering by Hendra virus F protein: role of G

描述(申请人提供)：我们实验室的目标是阐明人类副粘病毒副流感病毒3型(HPF3)发病的分子机制。在这项申请中，我们建议将我们在副粘病毒进入和融合研究方面的专业知识应用于Hendra病毒，Hendra病毒是一种新的副粘病毒，对人类具有潜在的致命性，被视为可能的生物恐怖主义因素。对于HPF3，我们的中心假设是受体结合蛋白血凝素神经氨酸酶(HN)与细胞受体(S)的相互作用对病毒生命周期的几个基本组成部分--结合、进入、融合和释放--至关重要，并调节致病性。Hendra病毒的提议直接源于我们的论证，即HPF3 HN受体结合是HN在融合促进中发挥作用的关键第一步，并导致触发F蛋白介导融合。对于亨德拉病毒，受体结合蛋白(G)的表达是F蛋白介导融合所必需的。我们的总体假设是，Hendra G与受体结合，就像HPF3 HN与唾液酸结合一样，触发F蛋白介导融合。对这一机制的研究和分析Hendra病毒中F蛋白的触发/激活的分析方法的发展应该会导致干扰病毒进入这一关键步骤的策略。 Triggerinq Hendra病毒F介导融合：G在激活F中的作用 (1)使用物理或化学探针改变G介导的F的激活来研究G触发F的过程。我们将通过用其他蛋白质替代G来改变G受体的结合，或者用合成肽、脂类和/或温度改变G促进的融合来影响G激活F的功能。 (2)确定G中参与激活F的残基：利用G蛋白中影响G促进F介导的融合的突变来研究F激活的机制。我们将使用来自相关副粘病毒的信息，包括HPF3，来确定Hendra G蛋白中影响G触发F融合能力的残基。 该建议利用了我们和其他人为相关副粘病毒开发的分析和策略，并将这些应用于理解Hendra F融合的激活。建议的研究结果将提供关于新出现的病原体威胁的融合和进入机制的重要新信息，并导致开发通过该病原体阻断致病的策略。

DESCRIPTION (provided by applicant): The objective of our laboratory has been to elucidate molecular mechanisms in pathogenesis of the human paramyxovirus parainfluenza virus type 3 (HPF3). In this application we propose to apply our expertise in the study of paramyxovirus entry and fusion to Hendra virus, a new paramyxovirus that is potentially fatal in humans and is viewed as a possible agent of bioterrorism. For HPF3, our central hypothesis is that the interaction of the receptor-binding protein, hemagglutinin-neuraminidase (HN), with cellular receptor(s) is critical for several essential components of the viral life cycle -- binding, entry, fusion and release -- and regulates pathogenicity. The proposal for Hendra virus evolves directly from our demonstration that HPF3 HN receptor binding is the critical first step towards HN's role in fusion promotion, and results in triggering of F protein to mediate fusion. For Hendra virus, expression of the receptor binding protein (G) is required in order for the F protein to mediate fusion. Our overall hypothesis is that Hendra G binding to receptor, like HPF3 HN binding to sialic acid, triggers F protein to mediate fusion. The study of this mechanism and the development of assays to analyze the triggering/activation of F protein in Hendra virus should lead to strategies for interfering with this key step in viral entry. Triggerinq Hendra virus F to mediate fusion: the role of G in activating F (1) Use of physical or chemical probes that alter G-mediated activation of F to study the process of G triggering F. We will either alter G-receptor binding by substituting other proteins in place of G, or alter G-promoted fusion using synthetic peptides, lipids and/or temperature to affect the function of G in activating F. In these ways we will characterize the process and requirements for G to trigger F-mediated fusion. (2) Identifying residues in G that participate in activating F: the use of mutations in G protein that affect G's promotion of F-mediated fusion to study the mechanism of F activation. We will use information derived from related paramyxoviruses, including HPF3, to identify residues in Hendra G protein that affect G's ability to trigger F to fuse. The proposal takes advantage of assays and strategies that we and others have developed for related paramyxoviruses, and applies these to understanding the activation of fusion by Hendra F. The results of the proposed studies will provide important new information about the fusion and entry mechanism of anemerging pathogen threat, and lead to development of strategies to block pathogenesis by this agent.