马尾松毛虫质型多角体病毒作为很有发展潜力的生物杀虫剂，是马尾松毛虫的重要致病源。尽管DpCPV 基因组全部 10 个 dsRNA 片段的序列已经被解读，但是质型多角体病毒（CPV）在分子生物学和侵染机理方面的研究还很薄弱。本课题将研究DpCPV主要结构蛋白VP5前体蛋白p50的合成，切割和组装机制；探寻p50被切割的氨基端（VP5）和羧基端（p50C）部分在病毒粒子和昆虫中肠细胞的定位；研究p50蛋白与DpCPV其他基因组片段编码蛋白的互相作用关系，探寻病毒粒子感染中肠过程中与p50发生相互作用的蛋白分子，阐述p50在病毒粒子组装和入侵过程中所起的作用。本研究对理解CPV病毒粒子的入侵和包装机制以及病毒粒子结构蛋白之间相互作用关系方面具有重要的理论意义。

Dendrolimus punctatus cytoplasmic polyhedrosis viruses (DpCPV), as a commercial pesticide, is an important pathogen of D. punctatus, an insect that is considered to be one of the most destructive pests in pine forests worldwide. The complete nucleotide sequence of DpCPV has been determined, but little is known about the molecular mechanisms underlying CPV infection. In this project, the formation, cleavage and assembly mechanism of p50, which is the precursor of DpCPV structural protein VP5, will be studied. The localization of Cleaved amino terminal （VP5） and carboxyl terminal of p50 （p50C） in CPV virions and insect midgut cells will be explored. Furthermore, we will prove the interaction between p50 and other proteins of DpCPV virions by means of yeast two-hybrid systerm and co-immunoprecipitation. In addition, we will explore which proteins of insect midgut recognize the p50, VP5 or p50C. The expected results of this project may help us to understand the assembly mechanisms of virions and to identify the essential proteins involved in the initial stages of viral infection.