一株鸡传染性支气管炎病毒地方分离株膜蛋白基因的遗传变异分析

Genetic Variations of Membrane Gene of Infectious Bronchitis Virus Strains Isolated in Shanxi Province

对从山西省分离到的1株IBV(IBVSX16)的膜蛋白基因片段进行序列测定及分析,结果发现,IBVSX16株膜蛋白基因含有一个长681bp的ORF,编码226个氨基酸残基组成的多肽,与疫苗株H120和中国分离株LX4推导的氨基酸序列比对发现,存在基因突变现象,未发现缺失和插入现象,变异主要发生在2～l7位。系统进化关系显示19株IBV毒株分属于5个群。IBVSX16株位于第II群,中国IBV分离毒株主要集中在第III群和第Ⅳ群,具有较明显的地理区域性,可见IBV分离株在基因进化关系上形成了自己较为独立的进化群。

Membrane（M） protein gene of IBVSX16 strain isolated in isolated in Shanxi was sequenced and analyzed. The results showed that the M gene of isolate was composed of 681 nucleotides, encoding polypeptide of 226 amino acid residues. Variations of the deduced amino acids of M gene mainly occurred at positions 2 to 17, deletion and insertion was not found in the N gene of IBVSX16 comparing with that of the IBV strains H120 and LX4. A phylogenetic tree based on amino acid sequences of M gene of the 19 IBV strains showed that these strains were classified into five distinct clusters. IBVSX16 strain was in cluster Ⅲ. Most of the Chinese IBV strains were included in clusters Ⅲ and Ⅳ, forming distinct phylogenetic groups in China.