Molecular analysis of astrovirus capsid assembly

描述（由申请人提供）：非包膜二十面体病毒的外壳蛋白在病毒生命周期中必须执行各种功能，例如外壳蛋白亚基组装成封闭外壳，病毒核酸的特异性包裹，衣壳的成熟，与宿主受体相互作用以及将遗传信息分解到新感染的细胞中。为了确定抗病毒治疗和预防病毒性疾病的有效靶点，需要在分子水平上彻底了解多种衣壳特性。我们选择用于研究的系统是星状病毒，这是一种二十面体单链RNA病毒，是人类和动物肠胃炎的病原体。对于外壳蛋白的哪些区域对不同的衣壳功能起作用，我们知之甚少。本应用程序的目的是测试我们基于人类星状病毒外壳蛋白序列所做的新的结构预测是否在生物学实验中表现出来。我们假设，星状病毒外壳蛋白的组装和RNA包装功能构成了一个独立的模块化结构域，与受体结合和内化所需的决定因素不同。我们的具体目标是：(1)通过表征一系列突变的表型，测试是否在生物学实验中展示了病毒粒子组装、颗粒成熟和RNA封装所需的外壳蛋白区域的功能预测。(2)通过构建星状病毒科不同血清型和种间的嵌合外壳蛋白分子，检测外壳蛋白“组装域”的模块化。这些研究的基本原理是，深入了解星状病毒组装、核酸包装、成熟和趋向性的分子机制，将使我们了解星状病毒外壳蛋白独特和共有的特性。此外，设计嵌合星状病毒颗粒的潜力，在颗粒表面显示特定的表位，可能具有实际应用，例如产生基于颗粒的疫苗。嵌合星状病毒颗粒表面抗原显示相关胃肠炎病毒如诺如病毒（一类B类生物恐怖剂），可作为多价预防性疫苗开发。从长远来看，我们期望这项工作不仅会增加对星状病毒粒子生物学的理解，而且还会导致治疗药物或疫苗的发展，以对抗人类病毒性胃肠炎。

DESCRIPTION (provided by applicant): Coat proteins of non-enveloped, icosahedral viruses must perform a variety of functions during the virus life cycle, such as assembly of the coat protein subunits into a closed shell, specific encapsidation of the viral nucleic acid, maturation of the capsid, interaction with host receptors and disassembly to deliver the genetic information into the newly-infected cell. A thorough understanding of the multiple capsid properties at the molecular level is required in order to identify potent targets for antiviral therapy and the prevention of viral disease. The systems we have chosen for study are the astroviruses, a family of icosahedral, single-stranded RNA virus that is a causative agent of gastroenteritis in both humans and animals. Very little is known about what regions of the coat protein contribute to the diverse capsid functions. The objective of this application is to test whether novel structural predictions we have made based on the coat protein sequence of the human astroviruses are exhibited in biological experiments. We hypothesize that the assembly and RNA packaging functions of the astrovirus coat protein constitute an individual, modular domain that is distinct from the determinants required for receptor binding and internalization. Our specific aims are: (1) To test whether functional predictions of regions of the coat protein required for virion assembly, particle maturation, and RNA encapsidation are exhibited in biological experiments, by characterizing the phenotypes of a series of mutations. (2) To test the modularity of the coat protein "assembly domain" by constructing chimeric coat protein molecules between different serotypes and species of the Astroviridae. The rationale for these studies is that insight into the molecular mechanisms of astrovirus assembly, nucleic acid packaging, maturation and tropism will inform us of unique and shared properties of astrovirus coat proteins. In addition, the potential to engineer chimeric astrovirus particles that display specific epitopes on the surface of the particle could have practical applications such as generation of particle-based vaccines. Chimeric astrovirus particles displaying surface antigens of related gastroenteritis virus such as norovirus, a Category B bioterrorism agent, could be developed as a polyvalent, preventative vaccine. In the long term, we expect that this work will add not only to the understanding of astrovirus particle biology, but also lead to the development of therapeutic drugs or vaccines to combat viral gastroenteritis in humans.