一株鸭源H4N6亚型禽流感病毒A/duck/Shanghai/Y20/2006的全基因组序列测定及遗传演化分析

为了解鸭源H4N6亚型禽流感病毒A/duck/Shanghai/Y20/2006(DK/SH/Y20/06)的来源、特征及其分子演化规律,进一步丰富水禽流感病毒的基因库,对该病毒8个基因片段分别进行了扩增和序列测定,利用分子生物学软件对测序结果进行序列分析,并与GenBank登录的相关病毒进行了遗传演化分析。结果表明,DK/SH/Y20/06的HA基因切割位点附近的氨基酸序列(PEKASR↓GLF)符合低致病力AIV的特征,其分子遗传演化关系属于欧亚分支;NA基因与A/mallard/Yanchen/2005(H4N6)在同一分支内,核苷酸序列同源性为98.3%;而PB2、PB1、NP、PA基因与目前在国内流行的H6亚型禽流感病毒关系密切;M基因与A/environment/Korea/CSM05/2004(H3N1)处于同一分支;而NS基因与A/wild duck/Korea/YS44/2004(H1N2)同源性最高。且DK/SH/Y20/06的8个基因与美洲H4N6亚型AIV分离株均不处在同一遗传进化分支上,相互之间遗传关系较远。可见,DK/SH/Y20/06可能是由H4N6、H6N2、H6N5、H3N1和H1N2等不同亚型来源的基因在鸭体内经过复杂重组演变的一株重组病毒。

Genome sequencing and genetic evolution analysis of entire genome of an A/duck/Shanghai/Y20/2006 (H4N6) avian influenza virus

To investigate the origin,characteristics and molecular evolution of duck-derived H4N6 subtype avian influenza virus(AIV) A/duck/Shanghai/Y20/2006(abbreviated to DK/SH/Y20/06) and enrich the epidemiologic data of waterfowl origin AIV,the entire genome of DK/SH/Y20/06 was amplified and subjected to genome sequencing.The molecular software was used for sequence analysis and phylogenetic tree construction of DK/SH/Y20/06 with some other reference sequences in GenBank.The results indicated that the amino acid motif of HA gene cleavage site was PEKASR↓GLF,which was the typical characterization of the low pathogenic avian influenza virus(LPAIV).The phylogenetic analysis indicated that the HA gene of the isolate was derived from the Eurasian lineage in the eastern hemisphere.The NA gene was at the same cluster with A/mallard/Yan chen/2005(H4N6),sharing 98.3% sequence similarity.The PB2 gene,PB1 gene,NP gene and PA gene of this isolate had genetically close relationships with H6 subtype AIV which is epidemic in China at present.The M gene fell into the same cluster with A/environment/Korea/CSM05/2004(H3N1).The NS segment had the highest similarity with A/wild duck/Korea/YS44/ 2004(H1N2).The eight genes were not at the same cluster and shared a low similarity with other H4N6 subtype avian influenza viruses isolated in North America.These data suggested that DK/SH/Y20/06(H4N6) was possibly a reassortant virus derived from H4N6 subtype,H6N2 subtype,H6N5 subtype,H3N1 subtype and H1N2 subtype AIV by complex gene recombination in duck.