杆状病毒在感染过程中通过其核壳体蛋白P78/83介导产生的肌动蛋白聚合具有时序性和空间性的动态特征：病毒感染早期，胞质中产生一过性的肌动蛋白聚合将病毒核壳体推入胞核；病毒感染晚期，核内二次肌动蛋白聚合辅助新生核壳体装配。然而目前该动态特征的形成机理未知。我们前期实验发现宿主细胞可以通过作用于P78/83的N-末端引起P78/83降解，而病毒蛋白C42则通过与P78/83的相互作用抑制其降解。这提示P78/83的稳定性和功能状态受制于宿主和病毒两方面的动态调控，而这种针对P78/83的动态调控很可能就是病毒感染过程中肌动蛋白聚合的时序性与空间性的形成机理。本研究分别从宿主和病毒两个角度探讨它们调控P78/83的机制及其对肌动蛋白聚合与病毒复制的影响。这不仅有助于了解杆状病毒感染过程中肌动蛋白聚合的动态特征形成机理，更加在细胞生物学层面揭示了一种通过蛋白质降解途径来调控肌动蛋白聚合的全新方式。

The actin polymerization induced by baculovirus nucleocapsid protein P78/83 during virus infection possesses specific temporal and spatial patterns. At early phase of virus infection, transient actin polymerization occurs at host cytoplasm and pushes the nucleocapsid moving towards nuclear membrane; At late phase of virus infection, secondary actin polymerization occurs at host nucleus and assists the assembly of de-novo synthesized nucleocapsid. However, the mechanism of the dynamic actin polymerization during baculovirus infection remains unknown. According to our preliminary data, host cell rapidly degrades P78/83 through its N-terminal sequence, whereas virus nucleocapsid protein C42 stablizes P78/83 via C42-P78/83 interaction. This phenotype suggests the stability and functional status of P78/83 are dynamically regulated by host cell and virus, which may possibly be attributed to the specific temporal and spatial patterns of actin polymerization during baculovirus infection. This research will investigate the mechanism of how P78/83 is regulated by host cell and virus, as well as its impact upon actin polymerization and virus replication. The significance of this research will help understand the formation of dynamic actin polymerization during baculovirus infection, and reveals a novel regulation method of actin polymerization through protein degradation at cell biology level.