Uncoating of a Helical Virus: Cotranslational and Coreplicational Disassembly Mechanisms

螺旋病毒的脱壳：共翻译和共复制拆卸机制

• 批准号: 9726966
• 负责人: Bruce Webb
• 金额: $ 14.95万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-15 至 2002-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9726966&HistoricalAwards=false
• 关键词: Uncoating; Helical; Virus; Cotranslational; Coreplicational

Shaw (University of Kentucky) EPSCOR 9726966 Uncoating of a Helical Virus: Cotranslational and Coreplicational Disassembly Mechanisms 1. Technical Of all the stages of the infection process by an animal or plant virus, uncoating of the viral genome or disassembly of the virus particle is one of the least understood. This study examines tobacco mosaic virus (TMV), as its positive-sense RNA genome is enclosed (encapsidated) in rod-shaped particles. TMV particles undergo bidirectional disassembly after being introduced into plant protoplasts. The viral RNA is initially uncoated in the 5'-to-3' direction and the process is completed by the removal of coat protein molecules (subunits) in the 3'-to-5' direction. Two hypotheses are set forth to account for the bidirectional disassembly: (1) in vivo uncoating begins by a cotranslational disassembly mechanism in which the removal of subunits in the 5'-to-3' direction is coincident with ribosome translocation during translation of the first ORF of the viral RNA; (2) in vivo uncoating is completed by a coreplicational disassembly mechanism in which the viral polymerase proteins (encoded by the first ORF and/or its readthrough sequence) are involved in the removal of subunits in the 3'-to-5' direction and the synthesis of progeny minus-strand viral RNA molecules. These hypotheses are tested by determining the behavior of various TMV mutants. The possibility that regions in the polymerase proteins that are not involved in replication may be required for 3'-to-5' disassembly will also be explored. The significance of this study lies in its atttempt to understand a stage of life in which the ultimate success or failure of a virus to initiate infection in host cells is determined. 2. Non-technical Particles of tobacco mosaic virus (TMV) disassemble in inoculated plant cells, which allows the genome to be released so that the production of progeny virus particles can proceed, inducing the pathogenic state in the host organism. In this process, about 75% of the subunits is first removed, sequentially, beginning at one end of the viral genome; the remainder is then removed proceeding from the other end. The first step may involve concomitant synthesis of viral proteins, and the other may involve the production of copies of the viral RNA. Experiments are designed to examine the validity of each of these hypothetical mechanisms.

Shaw（肯塔基大学） EPSCOR 9726966 螺旋病毒的脱壳：共翻译和共复制拆卸机制 1. 技术 在动物或植物病毒感染过程的所有阶段中，病毒基因组的脱壳或病毒颗粒的拆卸是其中之一最不被理解的。这项研究检查了烟草花叶病毒 (TMV)，因为其正义 RNA 基因组被封闭（包裹在棒状颗粒中）。 TMV颗粒被引入植物原生质体后会进行双向分解。 病毒RNA最初在5'至3'方向上被脱去，并且该过程通过在3'至5'方向上去除外壳蛋白分子（亚基）来完成。 提出了两个假设来解释双向拆卸：（1）体内脱壳是通过共翻译拆卸机制开始的，其中亚基在 5' 至 3' 方向上的去除与第一个亚基翻译过程中的核糖体易位一致。病毒RNA的ORF； (2) 体内脱壳是通过共复制拆卸机制完成的，其中病毒聚合酶蛋白（由第一个 ORF 和/或其通读序列编码）参与 3' 至 5' 方向亚基的去除，并且子代负链病毒RNA分子的合成。通过确定各种 TMV 突变体的行为来检验这些假设。 还将探讨聚合酶蛋白中不参与复制的区域可能是 3' 至 5' 拆卸所需的可能性。这项研究的意义在于它试图了解决定病毒最终成功或失败感染宿主细胞的生命阶段。 2. 非技术性 烟草花叶病毒（TMV）颗粒在接种的植物细胞中分解，使基因组释放，从而可以继续产生子代病毒颗粒，从而诱导宿主生物体的致病状态。在此过程中，大约 75% 的亚基首先从病毒基因组的一端开始依次被去除；然后从另一端开始移除剩余部分。第一步可能涉及病毒蛋白的伴随合成，第二步可能涉及病毒RNA拷贝的产生。实验旨在检验这些假设机制的有效性。