【摘要】 在完成14株野禽源AIV PB1-F2基因克隆、测序的基础上,对其进行了同源性、遗传进化关系及氨基酸编码特征的比较分析。结果发现,H5N1亚型高致病性毒株A/lesser_kestrel/Harbin/194/2007(H5N1)PB1-F2的第37,48,50位氨基酸分别为精氨酸、脯氨酸、甘氨酸,与其他13个低致病性毒株均不相同(其分别为谷氨酰胺、谷氨酰胺、天冬氨酸)。为探讨这一现象,从NCBI Influenza Virus Resource中选取1 061个AIV毒株的PB1-F2基因序列进一步展开分析,结果表明:在第37,48,50位氨基酸位点上,97香港H5N1、其他H5N1及其他亚型AIV在此3个位点上氨基酸的构成存在着较为明显的差异,而且还呈现出了一定的规律和特点;并且研究还发现在此3个位点上,H9N2亚型毒株也表现出了较强的时间和空间分布特征。针对PB1-F2基因的遗传进化关系分析表明,H5N1及香港系毒株较其他AIV存在较远的遗传距离。随机的突变和重组似乎不足以解释这种差异及遗传距离形成的原因,其生物学意义有待于进一步探讨。更多还原

【Abstract】 Based on the completion of cloning and sequencing PB1-F2 genes of avian influenza viruses(AIV) isolated from 14 wild birds,we performed the analysis of their homology,phylogenetic relationships and composition of the coded amino acids.We found the amino acids 37,48,50 of PB1-F2 were arginine,proline,glycine respectively in a H5N1 high pathogenic avian influenza virus(HPAIV) strain,A/lesser_kestrel/Harbin/194/2007(H5N1),which was different from that of other 13 low pathogenic avian influenza virus(LPAIV) strains(glutamine,glutamine and aspartate respectively).For further exploring this phenomenon,1 061 AIV strains PB1-F2 genetic sequences which download from NCBI Influenza Virus Resource were compared,the results showed that the 97 Hong Kong H5N1 subtype,the other H5N1 subtype and the other subtypes of AIV were obvious different in the amino acid composition of these sites.Moreover these distinction also presented certain rules and characteristics.And we also found that the H9N2 subtype AIVs displayed obvious characteristics in temporal and spatial distributions of amino acid composition in these three sites.PB1-F2 genetic phylogenetic analysis showed that H5N1 and Hong Kong strains had a big genetic distance with other AIVs.It would not seem to be well explaned by genetic stochastic mutation and recombination,its biological significance remains to be further explored.更多还原