Distinct roles of cellular ESCRT-I and ESCRT-III proteins in efficient entry and egress of budded virions of Autographa californica multiple nucleopolyhedrovirus

　　論文信息：Qi Yue, Qianlong Yu, Qi Yang , Ye Xu , Ya Guo, Gary W. Blissard, Zhaofei Li. Distinct roles of cellular ESCRT-I and ESCRT-III proteins in efficient entry and egress of budded virions of Autographa californica multiple nucleopolyhedrovirus. J. Virol. doi:10.1128/JVI.01636-17

　　JCR分區(qū)Q1，IF=4.663

　　論文摘要：The endosomal sorting complex required for transport (ESCRT) machinery is necessary for budding by many enveloped viruses. Recently, it was demonstrated that Vps4, the key regulator for recycling of the ESCRT-III complex, is required for efficient infection of the baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV). However, ESCRT assembly, regulation and function are complex and little is known regarding details of participation of specific ESCRT complexes in AcMNPV infection. In this study, the core components of ESCRT-I (Tsg101 and Vps28) and ESCRT-III (Vps2B, Vps20, Vps24, Snf7, Vps46, and Vps60) were cloned from Spodoptera frugiperda. Using a viral complementation system and RNAi assays, we found that ESCRT-I and ESCRT-III complexes are required for efficient entry of AcMNPV into insect cells. In cells knocking down or overexpressing dominant-negative (DN) forms of the components of ESCRT-I and ESCRT-III complexes, entering virions were partially trapped within the cytosol. To examine only egress, cells were transfected with the dsRNA targeting an individual ESCRT-I or ESCRT-III gene and viral bacmid DNA or viral bacmid DNA that expressed DN forms of ESCRT-I and ESCRT-III components. We found that ESCRT-III components (but not ESCRT-I components) are required for efficient nuclear egress of progeny nucleocapsids. In addition, we found that several baculovirus core or conserved proteins (Ac11, Ac76, Ac78, GP41, Ac93, Ac103, Ac142, and Ac146) interact with Vps4 and components of ESCRT-III. We propose that these viral proteins may form an “egress complex” that is involved in recruiting ESCRT-III components to a virus egress domain on the nuclear membrane.