两株鸡源H9N2亚型禽流感病毒的分离鉴定和遗传进化分析

Isolation,identification and genetic evolution analysis of two H9N2 AIV isolates

为了解湖北鸡源禽流感病毒的遗传进化和氨基酸变异情况,将分离到的2株禽流感病毒进行全基因组测序及遗传进化分析。利用RT-PCR扩增流感病毒基因组片段,PCR扩增流感病毒片段、克隆至pMD18-T载体,并对序列特征进行生物信息学分析。结果表明:分离到的2株病毒高度同源,其HA和NA基因属于Y280谱系,PB1、PA、NP和NS基因属于SHF98-like谱系,PB2和M基因属于G1-like谱系;HA裂解位点均为-RSSR↓GLF-,具有低致病性流感病毒的分子特征;在HA蛋白上比当前流行株Y280多了一个潜在糖基化位点313(NCS);在234位点(对应H3编号中的226)产生了从Q到L的突变;在M2蛋白的31位点均产生了从S到N的突变。该2株H9N2亚型流感病毒为Y280谱系的病毒,这提示湖北地区可能也流行Y280-like分支禽流感病毒,虽然属于低致病性禽流感病毒(Low pathogenic AIV,LPAIV),但具有感染哺乳动物的潜在风险。

To investigate the amino acids substitution and genetic variation of influenza viruses in Hubei Province,two H9 N2 isolates were identified.The whole genome sequence of the isolated strains were amplified by RT-PCR,cloned into vector pMD18-T by PCR and analyzed by bioinformatics software.The results indicated that:These two H9 N2 isolates were highly identical.The HA and NA genes of the two H9 N2 isolates belonged to Y280-like lineage,PB1,PA,NP and NS genes belonged to SHF98-like lineage,and PB2 and M genes belonged to G1-like lineage;Molecular analysis of whole genome sequence found that the amino acid sequence of HA genes of the two isolates had-RSSR↓GLF-cleavage site,which represented low pathogenic avian influenza virus strain;Compared with the prevalent strain Y280,the two H9 N2 isolates contained 313(NCS) potential glycosylation site in HA protein.The position L234 Q(H9 numbering) of HA gene of the H9 N2 isolates was mutated;The position N31 S in M2 protein of the H9 N2 isolates were mutated.In conclusion,the two H9 N2 isolates belonged to Y280-like lineage virus,suggesting that the Y280-like branch avian influenza virus might also be prevalent in Hubei Province,which was a low pathogenic avian influenza virus(LPAIV),but had the potential risk of infecting mammals.