H1N1猪流感病毒广西分离株HA基因序列分析

【目的】了解H1N1猪流感病毒广西分离株的分子特征,为广西猪流感疫情监控提供参考依据。【方法】采用RT-PCR对2011年分离获得的H1N1猪流感病毒广西分离株（A/swine/Guangxi/1/2011）的HA基因进行扩增,然后利用DNASTAR分析软件对测序基因片段进行整个阅读框架的核苷酸序列及其推导氨基酸序列同源性比对分析,并用MEGA4.0绘制遗传进化树。【结果】广西分离株HA基因长1701bp,编码566个氨基酸,核苷酸序列与经典SIV的同源性为88.0%~99.6%,与季节性H1N1人流感病毒的同源性为76.3%~77.3%,与欧洲类禽SIV分离株的同源性为72.9%~75.4%,与2009甲型H1N1流感病毒的同源性为99.2%~99.6%;从核苷酸遗传进化树可知,广西分离株与类禽H1N1流感病毒和人H1N1流感病毒分离株的亲缘关系较远,而与2009甲型H1N1流感病毒分离株的亲缘关系最近。广西分离毒株HA基因的裂解位点序列为IPSIQSR↓G,具有典型低致病性流感病毒的分子生物学特征;共有8个糖基化位点,其中6个位于HAl区,两个位于HA2区;广西分离株HA蛋白RBS位点的氨基酸同时具有人和猪流感病毒的特点。【结论】广西分离株（A/swine/Guangxi/1/2011）属于2009甲型H1N1流感病毒。

Analysis of HA gene sequence of a subtype H1N1 swine influenza virus isolated from Guangxi strains

Objective]This study was to determine molecular biology information of HA gene of H1N1 swine influenza virus isolated from Guangxi strains to provide references for monitoring swine flu in Guangxi. Method]To analyze HA gene of H1N1 from Genbank, the primer was designed, and then HA genes of A/swine/Guangxi/1/2011 （H1N1） influenza virus were cloned, sequenced and compared via DNASTAR software. A phylogenetic tree was made using MEGA 4.0. Result]The results indicated that the length of HA gene was 1701 bp and coded for 566 amino acids. Comparing with classical swine influenza H1N1, human-like H1N1 and Eurasian avian-like H1N1, the nucleotide homologies of HA genes were from 88.0% to 99,6%, from 76.3% to 77.3% and from 72.9% to 75.4%,respectively. Phylogenetic analysis re- vealed that the strain of A/swine/Guangxi/l/2011 （H1N1） belonged to classical swine influenza H1N1 lineage and was similar to the strain A/California/04/2009（H1N1）, while it did not resemble human-like H1N1 and bird-like HIN1 at all. Amino acid sequence at the HA cleavage site was IPSIQSR~,G, whieh had characteristics of low-pathogenic influenza viruses. Among the eight glycosylation sites, six sites were located in HA1 section and the rest in HA2. Amino acid in pro- tein RBS of Guangxi strains possessed characteristics of both human and swine influenza virus. Conclusion]This strain was pandemic（H1N1） 2009 virus and first isolated in Guangxi.