高通量测序一株天鹅源H5N8亚型流感病毒遗传演化分析

High-throughput sequencing and phylogenetic analysis of an H5N8 subtype avian influenza virus

为研究一株天鹅源H5N8亚型禽流感病毒(AIV)的遗传演化规律,本研究对2016年从山西省疾控中心送检天鹅样品中分离到的一株H5N8亚型流感病毒(A/swan/Shanxi/6/2016)的全基因组序列进行高通量测序及遗传演化分析。结果显示,分离的病毒为Clade 2.3.4.4分支高致病禽流感病毒(HPAIV);BLAST分析显示该分离株的NP基因与H3N8亚型AIV的NP基因具有较高同源性,而其它基因节段则分别与来自其它国家的H5N8亚型AIV的相应基因节段同源性较高,进一步选取与各基因节段核苷酸同源性较高的病毒株作参考序列构建其系统进化树,推测该分离株为一株重组病毒株。特殊氨基酸位点分析显示,其具有典型的禽型受体结合位点和典型的人型受体结合位点。并且M1蛋白、NS1蛋白和PB2蛋白具有H5N1亚型AIV对鼠致病性增强的分子标志,提示该株野鸟源流感病毒可能具备感染哺乳动物的能力。本研究对H5N8亚型AIV的综合防控具有一定的指导意义。

To understand the genetic evolution of H5N8 subtype influenza virus （A1V）, the whole genome sequencing by high-throughput sequencing and phylogenetic analysis were conducted for an H5N8 subtype influenza virus （A/swan/Shanxi/ 6/2016） isolated from swan samples collected by Shanxi Provincial Center for Disease Control in 2016. The results showed that the isolate was a highly pathogenic AIV （HPAIV） belonged to Clade 2.3.4.4. The sequence alignment revealed that all genes shared the highest homologous to H5N8 subtype AIV from other countries, except NP gene sharing the highest homologous to H3N8 subtype A1V, and further analysis of the phylogenetic tree constructed by high nucleotide identity strains indicated that the isolate probably was a natural reassortant AIV. Analysis of special amino acid loci showed that the isolate possessed both typical avian and human receptor binding sites. Furthermore, there were molecular characterizations of enhanced pathogenicity to mice in M1, NS1 and PB2 protein of H5N1 subtype AIV, providing potential possibilities for the isolate from the wild bird to infect mammals. To a certain extent, this study has great significance to the comprehensive prevention and control of H5N8 subtype AIV.