Sequence Analysis Of The N Nucleocapsid Protein Gene Of Infectious Bronchitis Virus Strains In Sichuan,China

The nucleocapsid protein gene of Avian Infectious Bronchitis Virus which encodes the nucleocapsid protein is the most conservative gene,so it is important to study the nucleocapsid protein gene. RT-PCR was employed to amplify 5 strains of IBV,including two standard stains(M41,H120) and 3 field strains (SAIBWJ,SAIB20 and SAIB14).. And for the first time,the sequences of three IBV field strains from Sichuan Province in China have been analyzed.A pair of primer designed according to multi-sequence comparing results of published IBV sequences in Genbank was used to amplify the nucleocapsid gene of 5 strains,the amplified RT-PCR product of all 5 strains is 1.2kb in length. Resulting RT-PCR products were ligated into the pUCIS plasmid's multiclone site,and after transformating,correct colonies were screened for inserts.The RT-PCR products of 3 field strains were sequenced. The results showed that the N gene is 1227bp in length encoding for 409 amino acids. Each of the three genes' sequence has been submitted to Genbank (Accession Number:SAIBwjis AY121091,SAIB2o is AY121092,andSAIBi4isAY121093.Comparison of the SAIBwj,SAIB2o and SAIB )4N gene sequences with the IBV M41 by the Genedoc software revealed that the nucleotide homogeneity between them is 97%,93% and 98%,and the amino acid homogeneity is 96%,94% and 97%. Phylogenetic analysis between 19 strains by Phylip software indicated that the SAIBWJ,SAIB H,H52 and H52-GD have closely related N sequences,and SAIB 2o,Gray,Ark99 and De072 have closely related N sequences. Conservative reagion analysis by Anthepro software indicated that there have three conservative reagions between 19 strains,87-102,143-159,254-268.