Cloning, Expression And Immunological Properties Of Group A Rotavirus Nsp1 Gene

Rotaviruses (RVs) belong to the family of Reoviridae, genus Rotavirus. The particle of RV is a double-strained RNA(dsRNA) virus of icosahedral symmetry, measures 75nm in diameter, and consists of three layers without envelope. RV infection is the chief etiologic agent of viral gastroenteritis of humans, mammals and birds. There are about 600 000 childern died from RV caused acute gastroenteritis globally each year. RV genome has 11 segments of dsRNA, which encode 6 structural proteins (VP1-VP4, VP6, VP7) and 6 non-structural proteins (NSP1-NSP6). RVs can fall into seven groups (A to G) according to the antigenic specificity of the VP6 protein. Group A RVs are the major cause of acute gastroenteritis in infants and young children.The non structural protein 1 (NSP1) plays a very important role in interaction between virus and host. In this article, the full-length gene of the NSP1 of strain TB-Chen was expressed in E.coli BL21(DE3) cells using gene cloning and expression technologies, and immunogenicity, synthesis and subcellular distribution of the NSP1 protein in RV infected cells, and phylogenesis and genotypes of the NSP1 were studied. The results showed that the recombinant NSP1 protein (rNSP1) could be highly expressed in E.coli BL21(DE3) cells, which possesses 34.4% of total cell proteins. The rNSP1 could elicit specific antibodies in guinea pigs, and the antibodies could react with the rNSP1 itself and NSP1 protein expressed in SA11 infected or Wa infected MA 104 cells by Western blot and immunofluoresence assay. The results of immunofluoresence also showed that NSP1 protein was aggregated in the cytoplasm and formed radiate granular structure around nucleus of SA11 infected MA 104 cells but not in Wa infected MA 104 cells. At least 16 recognized genotypes of NSP1 were classified in group A RVs, based on diversity of sequences of the NSP1 open reading frame (ORF), and TB-Chen strain NSP1 was defined as genotype A2. RVs with different NSP1 genotype have specific host ranges, RVs possessing the same NSP1 genotype can infect different species, Same species can be infected with RVs possessing different NSP1 genotypes. The results obtained in the present study are important for further studying on structure, function and immunological properties of the NSP1.