Xiao Jun, Yan Chuanzhe, Zhou Wei, Li Jun, Wu Hui, Chen Tiansheng, Feng Hao
State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, China; College of Life Science, Hunan Normal University, Changsha 410081, China.
College of Fisheries, Huazhong Agricultural University, Wuhan 410081, China.
Fish Shellfish Immunol. 2017 Apr;63:261-269. doi: 10.1016/j.fsi.2017.02.023. Epub 2017 Feb 21.
Mitochondrial antiviral signaling protein (MAVS) is an adaptor protein of the innate immune system of higher vertebrate. In this paper, the transcription profile of black carp MAVS (bcMAVS) in host cells in response to spring viremia of carp virus (SVCV) and grass carp reovirus (GCRV) infection was identified. EPC cells expressing bcMAVS possessed obviously enhanced antiviral activity against both SVCV and GCRV. Immunofluorescence (IF) staining data demonstrated that bcMAVS molecules were redistributed and formed aggregates on the mitochondria of EPC cells after virus infection. Co-immunoprecipitation (co-IP) assay in HEK293T cells demonstrated that bcMAVS proteins bound to each other, which suggested that this fish protein owned self-association in vivo. IF assay identified that the transmembrane (TM) domain of bcMAVS was crucial for its mitochondrial localization. Co-IP assays among bcMAVS mutants demonstrated that both N-terminal caspase recruitment domain (CARD) and TM domain were indispensible for dimerization of bcMAVS. It was interesting that Truncated-bcMAVS possessed much enhanced interferon-inducing activity and antiviral ability than wild type bcMAVS, which only contains CARD and TM. All the data generated in this study support the idea that oligomerization of bcMAVS on mitochondrion is crucial for the antiviral ability of bcMAVS, which is depend on both CARD and TM domain of this fish MAVS orthologue.
线粒体抗病毒信号蛋白（MAVS）是高等脊椎动物固有免疫系统的一种衔接蛋白。本文鉴定了草鱼MAVS（bcMAVS）在宿主细胞中对鲤春病毒血症病毒（SVCV）和草鱼呼肠孤病毒（GCRV）感染的转录谱。表达bcMAVS的EPC细胞对SVCV和GCRV均具有明显增强的抗病毒活性。免疫荧光（IF）染色数据表明，病毒感染后，bcMAVS分子在EPC细胞的线粒体上重新分布并形成聚集体。在HEK293T细胞中进行的免疫共沉淀（co-IP）分析表明，bcMAVS蛋白相互结合，这表明这种鱼类蛋白在体内具有自我缔合能力。IF分析确定bcMAVS的跨膜（TM）结构域对其线粒体定位至关重要。bcMAVS突变体之间的co-IP分析表明，N端半胱天冬酶招募结构域（CARD）和TM结构域对于bcMAVS的二聚化都是不可或缺的。有趣的是，截短的bcMAVS比仅包含CARD和TM的野生型bcMAVS具有更强的干扰素诱导活性和抗病毒能力。本研究产生的所有数据支持这样一种观点，即bcMAVS在线粒体上的寡聚化对于bcMAVS的抗病毒能力至关重要，这取决于这种鱼类MAVS直系同源物的CARD和TM结构域。
