Sequence Analysis Of S1 Gene And E Gene Of IBV And Prokaryotic Expression Of E Gene

Avian infectious bronchitis is a high contagious disease caused by avian infectious bronchitis virus (IBV) belonging to Coronavirus. The disease can result in huge economic loss and threaten poultry husbandry worldwide. IBV have a number of serotypes and its antigen can vary easily, that make it difficult to diagnose and prevent the disease. S1 protein is the main immunogenic protein of IBV, which can induce fusion of host cells and stimulate animal body to produce virus neutralizing antibody and HI antibody, besides S1 gene possess obvious specificity of virus type and easily happen to vary that make more serotypes of IBV. Another viral structural protein of IBV, envelope protein, plays an important role in the course of replication, equipment and budding of the virus. In order to know prevalence and variation of IBV, find out the method highly expressing E protein in prokaryotic systems and research its biological characters, we processed these study.Five S1 genes and seven E genes of IBVs isolated in China were respectively cloned in pGM-T-esay vector and pGEM-T-esay vector successfully and sequenced. Respectively comparing the S1 and E sequences with other S1 and E genes of IBV sequences in GenBank by biosofts, Sequence analysis indicate S1 gene and E gene exist obvious variation. Variation of S1 gene mostly take place in amino acids positions at 69 to 81 and 142 to 150, variation of S1 gene mostly take place in amino acids positions at 11 to 17 and 87 to 96. Phylogenetic analysis showed all isolates of this study have a closely relationship with reference nephropathogenic IBV, these isolates of China belong to the same lineage and differ from IBV isolates of Europe and America suggesting that the geographical distribution plays a significant role in the evolution of IBV.The E gene of isolate HBN was cloned into pET32a(+) vector with strain BL21 (DE3)plysS as the corresponding expression host. The E gene could be successfully highly expressed in this system by adding 1mM TPTG, the protein produce of expression was analyzed by SDS-PAGE and Western-blotting. Resolution analysis of protein indicate the recombinant protein was soluble.Sequence analysis of S1 genes and E genes in this study will provide some evidence for IBV epidemiological study. The prokaryotic expression of the recombinant E protein in E.coil will establish a good foundation for production of soluble envelope protein and studying its biological functions.