1981～2005年中国H1N1甲型流感病毒血凝素基因的HA1演变特征

Evolutionary Characterization of HA1 of Influenza H1N1 Hemagglutinin Gene Surveyed in 1981-2005 in China

为了解1981～2005年我国H1N1甲型流感病毒血凝素基因的HA1演变特征，选取H1N1甲型流感病毒370株，提取病毒RNA，经逆转录和聚合酶链反应扩增HA1并测序，测定的序列用生物信息软件分析，与GenBank中相关序列比较，并对推导的编码氨基酸序列进行基因特性分析。结果表明：HA1氨基酸的变异表现为抗原决定簇4个区均有变异，Sb区和Ca区变化较大；HA1受体结合位点（RBS）的前壁130环的第134位赖氨酸从1991年起在部分毒株HA1序列上开始缺失，以后缺失株逐步增多，自2000年起测定的所有毒株上该氨基酸全部缺失，同时这些缺失株的第137位氨基酸也全部由苏氨酸替换为丝氨酸；糖基化位点从增多到减少，最后稳定在7个；1981～2004年我国H1N1甲型流感病毒血凝素HA1编码的氨基酸在种系发育树上同年代基本呈现集中分布，与时间和地域无关，2005年毒株分成两个分支在时间上有明显差异。

To understand the evolutionary characterization of HA1 of HIN1 influenza virus HA gene circulaing from 1981 to 2005 in China, viral RNAs of 370 H1N1 strains were extracted and transcribed into cDNA by reverse transcriptase and amplified by PCR. The products of PCR were sequenced. The sequences were analyzed through biometic software. The results showed that all the four antigenic sites were mutated, bigger change occurred on the Sb and Ca sites; the 130 loop of receptor binding sites（RBS） of HA1 amino acid deleted at the 134th site in 1991 firstly, then the number of the deleted strains were increasing, since 2000, all the strains had deleted at the 134th site, and simultaneously, the amino acid at 137th site was substituted by S for T. The change of HA1 glycosylation sites was found and 7 sites kept stable from 2000 to 2005. The H1N1 strains of the same year almost clustered in the same group on the phylogenetic tree and were irrelevant to virus isolated time and area. There appeared two groups of 2005 H1N1 virus strains that differed in time of virus isolation.