Interaction of Sindbis Virus with Cellular Processes

描述（由申请方提供）：披膜病毒科甲病毒属包含许多重要的人类和动物病原体，广泛分布于除南极地区外的所有大陆。一些甲病毒，例如，委内瑞拉（VEEV）、东部（EEEV）和西部（WEEV）马脑炎病毒引起严重人类疾病。其他病毒，如辛德毕斯（SINV）和塞姆利基森林（SFV）病毒，对人类的致病性较低，但它们采用类似的复制策略，并用于研究病毒RNA合成的基本问题。在上一个资助期内，我们在理解SINV基因组复制方面取得了一些重要的发现，包括i）揭示了RNA启动子元件的结构和功能; ii）证明旧世界甲病毒特异性nsP 2和新世界特异性衣壳蛋白在病毒-宿主细胞相互作用中的关键作用，在脊椎动物来源的细胞中的转录关闭和细胞病变效应的发展，和iii）鉴定SINV特异性蛋白复合物的病毒和细胞组分。最重要的是，我们最近的研究表明，脊椎动物起源的细胞中的SINV复制导致两种类型的nsP 3-含有蛋白质复合物的形成。基于我们的数据，我们假设第一种类型的nsP 3特异性复合物最初形成于细胞膜上，并且在胞吞作用之后，仍然与内体样的含膜细胞器相关联。这些复合物在病毒特异性RNA合成中充当复制复合物（RC）。第二种类型的复合物与细胞骨架相关，具有相似的病毒，但不同的细胞成分，通常在细胞应激颗粒（SG）中检测到。后者复合物或者作为SG形成的竞争者起作用和/或在病毒蛋白的优先合成中起作用。拟议的研究计划集中在两个广泛的具体目标：i）研究SINV复制过程中病毒特异性蛋白质复合物的形成，以及ii）分析SINV复制中细胞和病毒蛋白质的功能。公共卫生相关性：甲病毒包括一组广泛分布的人类和动物病原体;其中一些引起高度衰弱性疾病，并在美国构成严重的公共卫生威胁。该提案的目标是了解细胞环境在病毒感染中的作用。对病毒生长所必需的细胞蛋白的鉴定将导致新的抗病毒治疗策略的发展。

DESCRIPTION (provided by applicant): The Alphavirus genus in the Togaviridae family contains a number of significant human and animal pathogens that are widely distributed on all continents, excluding the Antarctic regions. Some of the alphaviruses, e.g., the Venezuelan (VEEV), eastern (EEEV) and western (WEEV) equine encephalitis viruses, cause severe human disease. Others, such as Sindbis (SINV) and Semliki Forest (SFV) viruses, are less pathogenic for humans, however, they employ similar replication strategy and are used for studying fundamental issues of the viral RNA synthesis. In the previous grant period, we made a number of important findings toward understanding the SINV genome replication that include i) uncovering the structure and functioning of the RNA promoter elements; ii) demonstration of the critical roles of the Old World alphavirus-specific nsP2 and the New World-specific capsid protein in virus-host cell interactions, in the development of transcriptional shutoff and cytopathic effect in the cells of vertebrate origin, and iii) identification of the viral and cellular components of the SINV-specific protein complexes. Most importantly, our recent studies demonstrated that SINV replication in the cells of vertebrate origin leads to formation of two types of nsP3-containing protein complexes. Based on our data, we hypothesize that the first type of nsP3-specific complexes is initially formed on the cellular membrane and, following endocytosis, remains associated with endosome-like, membrane-containing organelles. These complexes serve as replication complexes (RCs) in virus-specific RNA synthesis. The second type of complexes is associated with the cytoskeleton and has similar viral, but different cellular components, which are normally detected in cellular stress granules (SGs). The latter complexes either function as competitors for SG formation and/or serve in the preferential synthesis of viral proteins. The proposed research plan is focused on two broad Specific Aims: i) to study virus-specific protein complexes formation during SINV replication, and ii) to analyze functioning of cellular and viral proteins in SINV replication. PUBLIC HEALTH RELEVANCE: Alphaviruses comprise a group of widely distributed human and animal pathogens; some of them induce highly debilitating diseases and represent a serious public health threat in the US. The goal of this proposal is to understand the role of the cellular environment in viral infection. Identification of the cellular proteins that are essential for virus growth will lead to development of new antiviral therapeutic strategies.