Clone and genetic variation analysis of N gene of nephropathogenic avian infectious bronchitis virus isolates

The complete N genes of eight avian infectious bronchitis viruses (IBV) isolated from different places of Shaanxi province were amplified by using RT-PCR method. The products were ligated with Tvector separately and the transfered plasmids were obtained respectively. The N genes were sequenced in invitorgen cooperation. Sequences were analyzed among the eight isolates in China and the reference strains in GenBank by using DNAstar software. According to the analyzed results of N genes nucleotide, BO1 strain, YL strain,WH strain and YX strain share high identities,while the identities of G strain,BJ strain, WG strain and FF strain are low. The results of deduced amino acid sequences show that the mutation of N protein mainly display sporadic point mutation as 46,48,50,75,78,189,223,236,237,298,301,350,366 et al. Mutational site did not show obvious regularity.