摘要： 利用RT－PCR技术克隆了10株涵盖不同分离年代和不同毒力的H9N2亚型AIV 的NA基因，序列分析表明，10株AIV的NA基因的核苷酸和推导的氨基酸同源性高，进化稳定。系统进化树分析表明，其中NA基因都属欧亚大陆禽分支，H9N2流感病毒的分布与地域有相关性。其NA蛋白氨基酸序列潜在的糖基化位点以及氨基酸红细胞吸附位点出现的变化尚不能解释这些毒株生物学特性上的差别。但这些研究结果从理论上丰富了H9N2亚型禽流感的分子流行病学，也为进一步研究该类毒株的进化提供了依据。

关键词: H9N2, AIV, NA基因, 克隆, 序列分析

Abstract: NA genes of 10 H9N2 AIV strains, which cover all isolated ages and different virulence, were cloned by RT- PCR. The sequence analysis showed the homology of nucleotides of NA genes and their deduced amino acids between the 10 AIV strains was 91. 6% - 99. 0% and 91 9% - 100%, respectively, indicating the stead evolution of these chick-en-source H9N2 AIV strains. Phylogenetic analysis suggested that the NA genes of these H9N2 AIVs belonged to eurasia clade and their distribution displayed a certain regional correlation. The changes of potential glycosylation sites and erythrocyt e adsorption sites of the 10 strains could not explain the difference of their biological characteristics. The result of this research not only enriched the molecular epidemiology of H9N2 subtype AIV, but also provided the scient ific base for further studying the evolution of them.

Key words: H9N2 AIV, NA gene, Clone, Sequence analysis

中图分类号: 

• S858.31

• Q785