两株H9N2亚型猪流感病毒全基因进化分析

用RT-PCR方法扩增了H9N2亚型猪流感病毒河南株(Swine/Henar/Y1/09)和H9N2亚型猪流感病毒上海株(Swine/Shanghai/Y1/09)的8个基因片段,进行测序分析.结果表明,这两株猪流感病毒HA基因长度均为1701 bp,编码566个氨基酸,HA切割位点序列均为R-S-S-R-G,属非高致病性毒株；这两个毒株的HA蛋白均有8个潜在的糖基化住点.两个分离株的NA基因长度为1401 bp,编码467个氨基酸,这两个毒株均在茎区63、64、65位发生氨基酸缺失.两株猪流感病毒HA基因的同源性为96.6％,NA基因的同源性为98.6％.两株毒株的8个基因片段系统发生树分析表明它们均为重组体,与2008年上海地区健康鸡群中分离的H9N2亚型毒株(Ck/Shanghai/Y 1/2008)8个基因片段均分别属于同一个基因群.

PHYLOGENETIC ANALYSIS OF TWO H9N2 SUBTYPE SWINE INFLUENZA VIRUSES

The whole genomic sequences of H9N2 subtype Swine influenza virus Henan isolate(Swine/Henan/Y1/09) and Shanghai isolate(Swine/Shanghai/Y1/09) were amplified with RT-PCR and then sequenced and analyzed.The HA gene of both isolates was 1701 bp and encoded 566 amino acids.The amino acid sequence at HA cleavage site was R-S-S-R-G in these two isolates,which was non-highly pathogenic.Both isolates shared the same eight potential glycosylation sites in the HA protein.The NA gene of these two isolates was 1401 bp and encoded 467 amino acids.The 63th,64th and 65th amino acid residues were deleted in the NA protein of the two isolates.The nucleotide homologies of HA and NA genes between the two isolates were 96.6% and 98.6%,respectively.On the basis of phylogenetic analysis,these two H9N2 subtype Swine influenza virus isolates were reassortants,which had the same genetic origin with the isolate Ck/Shanghai/ Y1 /2008 obtained from a healthy flock in Shanghai.