质型多角体病毒衣壳蛋白VP5参与病毒RNA复制机制的研究

Cypovirus or cytoplasmic polyhedrosis virus (CPV) is a genus of double-stranded RNA (dsRNA) viruses, which infect insects, and belongs to the family Reoviridae. Due to its simple architecture of viral capsid, i.e. a single-layer capsid, CPV has been recognized as a simple and ideal model for studying the RNA replication of reoviruses, as well as other dsRNA viruses. Previous studies by our and other groups have revealed that VP5, one of the three major capsid proteins of CPV, can stabilize CPV capsid, and directly involve in CPV RNA replication as an RNA chaperone protein. Moreover, the applicant's recent study found that CPV VP5 can directly interact with the RNA-dependent RNA polymerase (RdRp) of CPV, and also possesses an NTPase activity. In this project, the applicant will determine the role of VP5-RdRp interaction in viral RNA replication, and reveal how the NTPase activity of VP5 affects other activities of VP5, such as its RNA chaperone activity, interaction with RdRp, and interaction with VP1 or VP3, using both in vitro and in vivo approaches. The accomplishment of this project will significantly deepen our understanding to the mechanisms of RNA replication of CPV, reoviruses, and probably other dsRNA viruses.

质型多角体病毒属于呼肠孤病毒科，是一种感染昆虫的双链RNA病毒，并因其简单的衣壳结构而成为研究呼肠孤病毒科及双链RNA病毒复制的理想模型。然而对该病毒，特别是其衣壳蛋白参与病毒核酸复制机制的认识目前还存在很多空白。质型多角体病毒结构蛋白VP5具有多种功能，能帮助稳定病毒衣壳结构，并能作为RNA分子伴侣参与病毒核酸的复制。申请人的前期研究表明VP5还能与该病毒复制酶结合，并具有NTPase活性。为揭示VP5在病毒复制中的作用机制，我们将深入研究VP5与复制酶相互作用在病毒RNA复制中的作用机制，探索其NTPase活性与VP5其他功能间的相互关系，并在细胞及昆虫水平揭示该蛋白在病毒核酸复制过程中的作用机制。本研究将更全面的揭示VP5在质型多角体病毒复制中的功能机制，极大的拓展我们对该病毒复制机制的认识，同时也将对呼肠孤病毒科及其他dsRNA病毒复制机制的研究提供借鉴，具有重要的科学价值。

参照本项目的计划任务书，本项目的所有相关任务均已经完成。任务完成情况良好，且不存在其他的相关问题。我们对CPV的RdRp蛋白活性进行了机制性的研究，并找到了该活性相关的突变位点以及病毒的核酸复制机制。同时我们也研究了VP5蛋白的NTPase活性的相关机制。找到了NTPase活性的关键性活性位点。通过蛋白相互作用实验来研究了CPV的RdRp复制酶活性与CPV的分子伴侣蛋白的多种功能之间的联系。相关的研究结果发表在SCI学术论文上。