ASTROVIRUS NONSTRUCTURAL PROTEINS

星状病毒非结构蛋白

• 批准号: 2862806
• 负责人: DAVID KIANG
• 金额: $ 3.84万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2862806
• 关键词: RNA virus; endopeptidases; fluorescence microscopy; immunoprecipitation; open reading frames; posttranslational modifications; protein localization; replicase; site directed mutagenesis; virus protein

Human astroviruses (H-Ast) are the prototype members of an important new family of RNA viruses that infect the gastrointestinal tract. The 6.8 kb positive sense RNA genome of H-Ast is organized with nonstructural proteins encoded at the 5' end by ORFs 1a and 1b, and the capsid protein(s) by ORF-2 at the 3' end. Sequence analysis indicates that ORF-1a encodes a 3C-like serine protease motif and a nuclear localization signal (NLS). ORF-1b encodes an RNA-dependent RNA polymerase (RdRp) motif, and its translation is dependent on (-1) ribosomal frameshifting at a specific signal found in the overlap region between ORF-1a and -1b. By this mechanism, the RdRp is expressed as part of a 1a/1b polyprotein that must be processed further to be functional. Our project focuses on determining how the viral NSPs are processed into functional subunits and where they are localized within the infected cell. We hypothesize that the putative viral 3C-like serine protease, encoded by ORF- I a, is responsible for cleavage of the ORF-1 a encoded product and 1a/1b polyprotein into functioning subunits, and that some of these cleavage products are directed to the nucleus by a functional NLS that is part of the 1a protein. Our specific aims are: 1) characterizating the role of the virally encoded protease in processing of the nonstructural gene products and 2) characterizing the subcellular localization of the viral nonstructural proteins. These studies will provide significant new information on the processing of the H-Ast nonstructural proteins and their subcellular localization. These data should contribute to our understanding of viral replication and ultimately, viral pathogenesis.

人类星状病毒（H-Ast）是一种重要的新病毒的原型成员。 感染胃肠道的RNA病毒家族。 6.8的 H-Ast基因组由3.5kb的正义RNA组成， 在5'端由ORF 1a和1b编码的蛋白质，以及衣壳 在3'末端通过ORF-2对蛋白质进行修饰。 序列分析表明 ORF-1a编码一个3C样丝氨酸蛋白酶基序， 定位信号（NLS）。 ORF-1b编码一个依赖RNA的RNA 聚合酶（RdRp）基序，其翻译依赖于（-1） 在重叠区发现的特定信号处的核糖体移码 ORF-1a和ORF-1b之间。 通过这种机制，RdRp表示为 1a/1b多聚蛋白的一部分，必须进一步加工， 不降低 我们的项目重点是确定病毒性NSP是如何 加工成功能亚基，并定位在 被感染的细胞 我们假设假定的病毒3C样 丝氨酸蛋白酶，由ORF-Ⅰ a编码，负责切割 ORF-1a编码产物和1a/1b多聚蛋白分成功能亚基， 并且这些裂解产物中的一些通过以下方式被导向细胞核： 是1a蛋白的一部分的功能性NLS。 我们的具体目标是： 1)表征病毒编码的蛋白酶在 非结构基因产物的加工和2）表征 病毒非结构蛋白的亚细胞定位。 这些 研究将提供重要的新信息， H-Ast非结构蛋白及其亚细胞定位。 这些数据应该有助于我们对病毒复制的理解 以及最终的病毒发病机制。