Identification and characterization of two cleavage fragments from the Aquareovirus nonstructural protein NS80  

作　　者：Qingxiu Chen Jie Zhang Fuxian Zhang Hong Guo Qin Fang 

机构地区：[1]State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China [2]University of the Chinese Academy of Sciences, Beijing 100039, China

出　　处：《Virologica Sinica》2016年第4期314-323,共10页中国病毒学（英文版）

基　　金：supported by funding from the National Natural Science Foundation of China (NO.31372565,31402340,31400139 and 31370190)

摘　　要：Aquareovirus species vary with respect to pathogenicity,and the nonstructural protein NS80 of aquareoviruses has been implicated in the regulation of viral replication and assembly,which can form viral inclusion bodies(VIBs) and recruit viral proteins to its VIBs in infected cells.NS80 consists of 742 amino acids with a molecular weight of approximately 80 kDa.Interestingly,a short specific fragment of NS80 has also been detected in infected cells.In this study,an approximately58-kDa product of NS80 was confirmed in various infected and transfected cells by immunoblotting analyses using α-NS80 C.Mutational analysis and time course expression assays indicated that the accumulation of the 58-kDa fragment was related to time and infection dose,suggesting that the fragment is not a transient intermediate of protein degradation.Moreover,another smaller fragment with a molecular mass of approximately 22 kDa was observed in transfected and infected cells by immunoblotting with a specific anti-FLAG monoclonal antibody or α-NS80 N,indicating that the 58-kDa polypeptide is derived from a specific cleavage site near the amino terminus of NS80.Additionally,different subcellular localization patterns were observed for the 22-kDa and 58-kDa fragments in an immunofluorescence analysis,implying that the two cleavage fragments of NS80 function differently in the viral life cycle.These results provide a basis for additional studies of the role of NS80 played in replication and particle assembly of the Aquareovirus.Aquareovirus species vary with respect to pathogenicity, and the nonstructural protein NS80 of aquareoviruses has been implicated in the regulation of viral replication and assembly, which can form viral inclusion bodies （VIBs） and recruit viral proteins to its VIBs in infected cells. NS80 consists of 742 amino acids with a molecular weight of approximately 80 kDa. Interestingly, a short specific fragment of NS80 has also been detected in infected cells. In this study, an approximately 58-kDa product of NS80 was confirmed in various infected and transfected cells by immunoblotting analyses using e-NS80C. Mutational analysis and time course expression assays indicated that the accumulation of the 58-kDa fragment was related to time and infection dose, suggesting that the fragment is not a transient intermediate of protein degradation. Moreover, another smaller fragment with a molecular mass of approximately 22 kDa was observed in transfected and infected cells by immunoblotting with a specific anti-FLAG monoclonal antibody or a-NS80N, indicating that the 58- kDa polypeptide is derived from a specific cleavage site near the amino terminus of NS80. Additionally, different subcellular localization patterns were observed for the 22-kDa and 58-kDa fragments in an immunofluorescence analysis, implying that the two cleavage fragments of NS80 function differently in the viral life cycle. These results provide a basis for additional studies of the role of NS80 played in replication and particle assembly of the Aquareovirus.

关 键 词：AQUAREOVIRUS nonstructural protein NS80 cleavage fragments subcellular localization functional analysis 

分 类 号：S941.41[农业科学—水产养殖]