对虾白斑综合症病毒PIF复合物的组成和功能研究

口服感染因子(per os infectivity factors, PIFs)，是最先在杆状病毒中发现的一类蛋白，它们主要以蛋白复合物的形式在口服感染中发挥必需功能。目前在5个科的大DNA病毒中都发现了PIF同源物，预示PIFs介导的口服感染是一个经典病毒入侵机制，然而其起源和演化规律尚不清楚。这类病毒中对虾白斑综合症病毒(white spot syndrome virus, WSSV)最为古老，每年给全球虾产业造成巨大损失，目前仍缺乏有效的防治手段。我们的前期研究发现，WSSV的4种PIF形成一个约720 kDa的功能未被揭示的PIF复合物，推测它参与病毒的口服感染。本项目拟在此基础上，利用Blue native PAGE结合质谱技术深入阐明WSSV PIF复合物的组成, 揭示PIF复合物在WSSV口服感染和系统感染中的作用，为研究PIFs的起源和演化以及WSSV的防治奠定基础。

Per os infectivity factors (PIFs) are a group of viral proteins which are essential for oral infections.PIFs were initially identified in baculoviruses, and most of them (9 out of ten) function as a protein complex (PIF complex) in oral infection. PIF homologs have been found in 5 different families of invertebrate large DNA viruses, implying the viral entry mechanism mediated by PIFs is ancient and conserved. However the origin and the evolution of PIFs is still a mystery. Among these large DNA viruses, white spot syndrome virus (WSSV) is the most ancient. WSSV is the causative agent of white spot syndrome (WSS), a disease that has led to severe mortality rates in cultured shrimp all over the world and resulted to huge economic loss annually while no effective treatments are available. Recently, we found that four WSSV PIFs composed a 720 kDa complex whose function remained elusive. We propose that the PIF complex contain more unknown components and is involved in WSSV oral infection. In this project, we aim to disclosure the components of the newly identified WSSV PIF complex, and to reveal its function in both virus oral infection and systemic infection. The results will extend our knowledge of PIFs origin and evolution, and also provide potential targets for the control of WSSV.