一株H_5N_1亚型禽流感病毒株NA基因的克隆与序列分析

Cloning and Sequence Analysis of NA Gene of a H_5N_1 Subtype Avian Influenza Virus Isolate

用RT-PCR方法从1个H5N1亚型禽流感病毒分离株A/Chicken/Guangdong/DH/1997扩增NA基因cDNA片段,将其克隆至pMD18-T载体,获得重组质粒pMD-NA,并对其核苷酸序列进行测定和分析。结果表明,该毒株的NA基因长度为1350bp,编码449个氨基酸,与其它H5N1亚型AIV分离株的核苷酸序列同源性为97.0%～99.4%,氨基酸序列同源性为97.7%～99.1%,提示禽流感病毒NA基因保守性较高。NA基因氨基酸序列的聚类分析表明该毒株与来自香港的A/Pheasant/HK/FY155/01和A/Ch/HK/FY150/01两个分离株处于同一进化枝,亲缘关系较近。

The cDNA fragment of neuraminidase（NA） gene was amplified from a H5N1 subtype avian influenza virus （AIV）isolate（A/Chicken/Guangdong/DH/1997） by RT-PCR. The cDNA fragment of NA gene was then cloned into pMD-18T vector and the recombined plasmid was sequenced. The results indicated that the NA gene consisted of 1350bp, coding for 449 amino acids. Nucleotide sequence and amino acid sequence homology of NA gene of this AIV isolate compared with other H5N1 AIV atrains were found to be 97.0% - 99.4% and 97.7% - 99.1% respectively. The results also showed that NA gene of AIV was relatively conserved. Clustering analysis of NA amino acid sequence revealed that the AIV strain A/Chicken/Guangdong/DH/1997, A/Pheasant/HK/FY155/01 and A/Ch/HK/FY150/01 were kindred, locating in the same evolution branch.