1株H5N6亚型禽流感病毒分子特征分析

Molecular characterization analysis of one H5N6 subtype influenza virus

目的 对从某活禽市场环境中分离出的1株H5N6亚型禽流感病毒（A/environment/Zhenjiang/C13/2013,en/c13）进行全基因组序列测定,以揭示其基因起源和分子遗传特征.方法 采用二代测序技术对该分离株进行全基因组测序,MEGA6.0软件进行序列比对和构建系统发生树.结果 分离株NA基因与近年来中国禽类中流行的H6N6亚型禽流感的NA基因处于同一进化分支,其他7个基因（PB2、PB1、PA、HA、NP、M和NS）都与近年来东亚地区流行的H5N1亚型禽流感的相应基因处于同一进化分支,分离株en/c13的HA蛋白裂解位点为PLREKRRKR ↓ GLF,是高致病性禽流感病毒的典型分子特征序列.HA蛋白上关键受体结合位点226和228位（按照H3亚型的HA蛋白序列排序）氨基酸分别是Gln和Gly,是典型的禽流感病毒受体结合特征.结论 奉研究从环境中分离到一株新的基因重配禽流感病毒,其中NA基因来源于H6N6禽流感病毒,而其他7个基因则来源于H5N1禽流感病毒.结果提示我国禽流感病毒基因重配频繁,进化活跃,需要加强对禽流感病毒的持续监测.

Objective One H5N6 subtype avian influenza virus,A/environment/ Zhenjiang/C13/ 2013,was isolated from environment in Zhenjiang in 2013 during epidemiological surveillance and was identified by HA/HI test and specific RT-PCR test.H5N6 AIV was subjected to genome sequencing to investigate the genomic composition.Methods The next-generation sequencing （NGS） Illumina MiSeq Platform was used to obtain complete genome sequence information from influenza virus isolates.MEGA6.0 software was used to align the eight fragments of the virus.The phylogenetic and molecular characteristics of the isolate were analyzed by Neighbor-Joining method.Results Blast searches demonstrated that the NA gene belonged to the same clade with H6N6 viruses currently circulating in China,whereas the other seven genes were found to be more similar to those of eastern Asian H5N1 AIV strains gene.The amino acid motif of cleavage site between HA1 and HA2 was PLREKRRKR ↓ GLF,which was the typical characteristics of the HPAIVs.The receptor binding site in the viral HA gene possesses the residues Gln 226 and Gly 228 （H3 numbering）,indicating an avian-like receptor binding specificity.Conclusion One H5N6 subtype avian influenza virus was isolated from environment,phylogenetic analysis showed that the NA gene belonged to the same clade with H6N6 viruses.The other seven genes belonged to H5N1 subtype.It suggests that strengthen the continuous surveillance of avian influenza A viruses is necessary.