3株H9N2亚型禽流感病毒全基因组序列进化分析

为明确3株不同源性的H9N2亚型禽流感病毒(AIV)A/Chicken/Jilin/22/13(简称JL22)、A/Chicken/Jilin/24/13(简称JL24)、A/Duck/Jilin/37/13(简称JL37)基因组的遗传变异情况,本试验采用RT-PCR技术,分别扩增出3株AIV的8个基因片段,克隆后进行序列测定。结果显示,3株H9N2亚型AIV的主要致病基因均属于经典的欧亚种系。氨基酸比对发现JL22的HA氨基酸序列与A/Chicken/Hong Kong/G9/97和A/Duck/Hong Kong/Y280/97的HA氨基酸序列相比,在551位多了1个潜在糖基化位点。JL22、JL24、JL37的HA序列,在226位的氨基酸残基均为Leu,具有同哺乳动物唾液酸受体结合的特性,说明对人的感染性增强。M基因在31位上均发生了Asn取代Ser的现象,说明这些病毒对金刚烷胺产生了耐药性。由系统进化树可知3株毒株亲缘关系较远,各个基因所属分支也不具有统一性,且部分基因分别与鸡源、鸭源和猪源3种源性流感病毒株高度同源,推测这3株毒株是不同动物不同毒株经过长时间进化而发生自然重排的产物。

Phylogenetic Analysis of the Complete Genome Sequence of Three Strains H9N2 Subtype Avian Influenza Viruses

In order to clarify the genetic variation of three different endogenous avian influenza viruses subtype H9N2 A/Chicken/Jilin/22/13 (JL22),A/Chicken/Jilin/24/13 (JL24) and A/Duck/Jilin/37/13 (JL37),eight gene fragments of the three viruses were amplified by RT-PCR,and then cloned and sequenced.The results showed that the main pathogenic genes of the three H9N2 subtype AIV belonged to the classic Eurasian species.Compared with A/Chicken/Hong Kong/G9/97 and A/Duck/Hong Kong/Y280/97,the amino acid sequence of HA of JL22 had a more potential glycosylation site at the location of 551.The amino acid residue at position 226 of HA of JL22,JL24 and JL37 were all Leu,sialic acid receptors in mammals had the same characteristics and it showed that it enhanced human infection.Asn substituted Ser phenomenon was occurred on M gene at 31 site,indicating that these viruses were resistant to amantadine.Phylogenetic trees could be seen three viruses distantly related strains,each gene belonged to a branch not a unity,and some genes from chicken,duck and swine origin influenza virus strains derived three kinds of highly homologous,it was speculated that three different strains of different animals were naturally rearrangement products after a long period of evolution .