山东省H5N6禽流感病毒血凝素与神经氨酸酶基因序列分析

Molecular analysis of hemaglutinin and neuraminidase genes of avian influenza A (H5N6) virus in Shandong province from 2015 to 2017

目的分析2015—2017年从环境中分离到的4株H5N6禽流感病毒毒株的血凝素(hemaglutinin,HA)与神经氨酸酶(neuramindase,NA)基因序列,探讨该病毒的遗传变异及分子生物学特征.方法对检测到的H5亚型禽流感病毒开展病毒分离、基因测序,利用MEGA 6.0对基因序列进行遗传进化和分子变异特征分析.结果山东省分离到的H5N6亚型HA、NA基因同源性分别为94.6%~99.4%和95.4%~98.6%;进化分析显示,其HA基因属于2.3.4.4支,分属于2个不同的分支.氨基酸序列分析显示HA和NA均存在多个位点的变异,糖基化分析显示有4~8个N-糖基化位点.结论H5N6病毒具备对禽类高致病的分子特征,但不具有感染人的受体结合特征.

Objective To analyze the sequences of hemaglutinin (HA) and neuramindase (NA) genes in four strains of avian influenza A (H5N6) virus isolated from environment during the period of 2015-2017, so as to explore genetic variations and molecular biological characteristics of the virus. Methods Virus isolation and gene sequencing were performed for avian influenza virus strains detected as H5 subtype. The genetic evolution and characteristics of molecular variation were analyzed by MEGA 6.0. Results The similarities of HA and NA genes in four avian influenza A (H5N6) virus strains isolated in Shandong province were 94.6%-99.4% and 95.4%-98.6%, respectively. The phylogenetic analyses indicated that the HA genes were grouped into 2 separated clades of the 2.3.4.4 cluster. The amino acid sequences analysis revealed multi-locus mutations both in HA and NA. Glycosylation analysis showed that there were 4-8 sites of N-glycosylation. Conclusions The avian influenza A (H5N6) virus strains showed molecular characters of high pathogenicity, but no sign of receptor-binding to facilitate the infections of human.