家蚕BmCPV是呼肠孤病毒科中结构最简单的dsRNA病毒之一，申请人等前期研究认为CPV转录是依赖于衣壳蛋白形变引起的结构蛋白之间的互作。本项目拟利用课题组已建立的MultiBac多基因高效表达系统，通过体外构建含CPV不同结构蛋白基因的重组菌株，直接侵染sf9等细胞，制备不同的VLPs，利用cryoEM三维重构获得3-4Å的近原子分辨率结构，解析BmCPV不同结构蛋白之间互作的活性位点和生物功能，阐明BmCPV复制的结构机制。通过测定BmCPV不同VLPs、TP和突变型mTP蛋白等NTPase活性，阐明BmCPV复制的生化机制。将生化与结构机制有机结合，诠释NTPase介导的BmCPV增殖/复制信号传导通路的分子机制，为RV、BTV和IBDV等呼肠孤病毒的药物设计提供新的靶标，有望推动CPV属、Reoviridae科或分节段dsRNA病毒“吸附→入侵→复制→释放”共性规律和防治策略研究。

Bombyx mori Cytoplasmic Polyhedrosis Virus (BmCPV) is one of the simplest dsRNA viruses in Reoviridae. Our recent study results indicated that BmCPV transcription was dependent on the interactions of structural proteins that caused by conformational change of capsid protein. We have established a high efficiency MultiBac expression system and obtained recombinant E.coli containing different foreign genes. And, Virus-like Particles can be assembled and purified via infecting sf9 cells directly. Then we can obtain 3–4Å structure of atomic resolution using cryo-electron microscope and three dimensional reconstruction. It will interpret the active sites and biological functions between different structural proteins. At the same time, the results can show the structure mechanism of BmCPV replication. We can reveal biochemical mechanism of BmCPV replication through detecting NTPase activity of different BmCPV-VLPs/mVLPs, turret protein (TP) and mutational TP proteins. The results could illustrate the signal transduction pathway of BmCPV virus proliferation that mediated by NTPase with biochemical molecular biology and structural biology. This study might make it more clear of the virus replication mechanism, such as CPV genus, Reoviridae or segmental dsRNA virus. And it will supply effective targets on drug design, disease control against Reovirus, such as rotavirus, BTV, IBDV, and etc.