摘要
为了从分子水平上掌握西藏各地区H9亚型禽流感病毒的遗传进化情况及其与国内外H9亚型禽流感病毒的变异情况和流行规律之间的关系,作者选择了2009年不同时间从西藏部分地市养殖场分离的3株禽流感H9N2亚型毒株,采用RT-PCR技术对其HA和NA基因进行扩增、克隆和测序,并对所得全序列进行同源性和遗传进化分析。结果显示,3株西藏分离病毒之间的HA和NA基因变异程度不大,同源性达到98%以上,在遗传进化中均属于欧亚分支中的类Bj/94亚分支,3株西藏分离毒的HA基因与Bj/94的同源性在核苷酸水平为88.7%～88.8%,在氨基酸水平为93.4%～93.6%;NA基因与Bj/94的同源性在核苷酸水平为92.7%～93.0%,在氨基酸水平为93.4%～94.0%;3株西藏分离毒株可能与Bj/94由同一毒株进化而来。由于基因突变使Tb/1毒株的HA基因在313位出现了1个新的糖基化位点,Tb/4毒株的NA基因缺失了146位的糖基化位点;唾液酸吸附位点上有明显的突变;HA的裂解位点附近和NA基因的受体结合位点区域内都有氨基酸突变。HA和NA基因的变异可能与适应高原缺氧、高海拔等特殊气候环境有关。
To evaluate the molecular characterization and the evolutional situation of the H9N2 avian influenza viruses（AIV） spreading in Tibet,the HA and NA genes of three AIV strains isolated from different farms in 2009 were amplified by RT-PCR and completely sequenced.The homology of three Tibet isolates was analyzed and the phylogenic characterization was analyzed with the other H9N2 viruses available in GenBank database.The results showed little degree of variation among the three isolates and the homologies of HA and NA gene are up to 98%.And the three Tibet isolates were belonged to the branch of the Bj/94-like sub-branch.The nucleotide homologies of HA gene between the Bj/94 and Tibet isolates were from 88.7% to 88.8%,and the homologies of the deduced amino acids of HA protein were 93.4%-93.6%.The nucleotide homologies of NA gene between the Bj/94 and Tibet isolates were 92.7%-93.0%,and the deduced amino acids of NA protein were 93.4%-94.0%.These results indicate that the three Tibet isolates maybe evolute from the virus Bj/94.The HA gene of virus Tb/1 contains a novel potential glycosylation site at site 313 and the NA gene of virus Tb/4 lost a potential glycosylation site at site 146 because of point mutation.The mutation happened in the connecting peptide of HA protein and the receptor binding domain of NA protein as well.The mutation in HA and NA genes maybe associated with the adaption of the virus to special climate and environment of the high altitude and high altitude anoxia.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2010年第12期1659-1666,共8页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
973项目(2010CB534002
2011CB505004)
科技重大专项(2008zx10004013
2009zx1004-109)
华中农业大学农业微生物国家重点实验室开放基金项目(AML-200904)
