我国鸡源与人源H9N2亚型流感病毒聚合酶PB1基因的关系分析

Analysis on the relationship of the PB1 polymerase genes between chicken and human H9N2 subtypes of influenza viruses

目的 通过对 1996～ 2 0 0 1年自我国部分养鸡场分离鉴定的 8株H9N2亚型鸡流感病毒聚合酶PB1基因测序 ,了解鸡源与人源H9N2亚型流感病毒聚合酶PB1基因的关系。方法 病毒在鸡胚中传代 ,自收获的尿囊液提取RNA ,通过RT-PCR ,扩增聚合酶PB1基因片段 ,并进行序列测定 ,测序结果采用PHYLIP软件在Internet网上分析处理 ,并用TreeView软件绘制系统进化树。结果 8株H9N2亚型鸡流感病毒聚合酶PB1基因的核苷酸同源性为 97 4 %～ 99 7% ,与三株人源H9N2病毒A/Guangzhou/ 333/ 99、A/HongKong/ 10 73/ 99、A/HongKong/ 10 74 / 99的同源性分别为 90 6 %～ 91 9%、90 4 %～91 5 %、90 2 %～ 91 3%。该 8株鸡源H9N2病毒PB1基因属于相同的进化分支 ,即A/duck/HongKong/Y2 80 / 97-like分支 ,而与该 3株人源株H9N2病毒属于不同的进化分支 ;尚未发现PB1基因属于A/ quail/HongKong/G1/ 97或A/duck/Hong/Y4 39/ 97分支的鸡源分离株。结论 在我国养鸡业流行的H9N2病毒分离株与目前已分离的人源株H9N2病毒其PB1基因属于不同的进化亚分支 ,人源株H9N2病毒PB1基因不是来源于鸡源H9N2病毒。

The relationship of the PB1 polymerase genes between the chicken and human H9N2 subtypes of influenza viruses was determined by means of sequencing of the gene fragments of 8 strains of the H9N2 subtypes isolated from 1996 to 2001 in China.Viruses were grown in embryonated hen eggs and the viral RNA was extracted from allantoic fluid.The partial PB1 polymerase gene fragments were amplified by RT-PCR,and the purified PCR products were sequenced using the CEQ sequence kit by direct method.Phylogenetic analysis was carried out by analyzing the data obtained with those of human H9N2 subtype of influenza viruses from GenBank database by using the PHYLIP software package,and the phylogenetic tree was drawn using TREEView software.The experimental results showed that the nucleotide homologies among 8 strains of chicken isolates were 97.4%-99.7% ,and those with 3 strains of human H9N2 subtypes,A/Guangzhou/333/99,A/Hong Kong/1073/99,A/Hong Kong/1074/99 were 90.6%-91.9%,90.4%-91.5%,and 90.2%-91.3% respectively.Phylogenetic analysis showed that the PB1 genes of 8 strains of chicken H9N2 subtypes located at the same branch of lineages,but located in different lineages from those of 3 human H9N2 viruses.No PB1 genes belonging to the A/quail/Hongkong/G1/97 or A/duck/Hong Kong/Y439/07 was found.It concludes that the PB1 genes of chicken H9N2 subtype belong to a different lineage from those of the human H9N2 viruses isolated in Hong Kong and Guangzhou,and the PB1 genes of human H9N2 strains are not derived from those of the chicken H9N2 viruses which are prevalent in chicken populations in China.