我国鸡源H9N2亚型禽流感病毒NS基因的分子进化分析

Analysis on the non-structural protein genes of avian influenza viruses subtype H5N1 isolated from chicken in China

目的为了明确国内鸡群中H9N2亚型AIV中非结构蛋白(NS)基因系统进化情况,对1998-2008年间分离自发病鸡群中的14株H9N2亚型禽流感病毒(AIV)进行了非结构蛋白(NS)基因的克隆和序列测定,得到了NS1和NS2蛋白的完整编码序列。将NS核甘酸序列及推定的氨基酸序列与GenBank中已有的参考序列作比对,结果14株AIV的NS基因同源性在92.9%～99.9%,在系统进化上均属于NS基因A等位基因群中的A/Chicken/Beijing/1/1994分支。综合已有的研究结果,表明尽管A/Quail/Hongkong/G1/1997分支和A/Duck/Hongkong/Y439/1997分支的NS基因曾偶尔传入鸡群,但并未在我国鸡群中建立稳定的亚系。国内的H9亚型AIV的NS基因仅稳定存在着A/Chicken/Beijing/1/1994分支。

Fourteen H9N2 avian influenza viruses （AIV） were isolated from sick chickens in China from 1998 to 2008. The sequences of the Non-structural（NS） gene of these isolates were determined by RT-PCR and sequencing, and the entire ORF sequences of NS1 and NS2 protein were obtained. The homology of these nucleotide sequences and the putative amino acid sequences were compared with several classic reference viruses of H9N2. These isolates were proved to be highly homologous in NS gene （92.9%-99.9% identity） and all belonged to A/Chicken/Beijing/1/1994-like group in the Asia bird-swine branch of allele A of HS gene phylogenetic tree. According to this study and previous reports of other researchers, NS gene of HgN2 subtype AIV in chickens of China is genetically stable and there is no enough evidence to support the establishment of other sub-lineages in chickens.