H9N2亚型禽流感病毒A/Chicken/Gansu/2/99株基因组的分子特征

目的测定H9N2亚型禽流感病毒A/Chicken/Gansu/2/99(CK/GS/2/99)分离株的基因组序列并与参考毒株进行同源性分析,阐明该毒株的遗传变异及分子特征。方法采集发病鸡泄殖腔样品,经鸡胚尿囊腔接种分离病毒,采用RT-PCR方法对CK/GS/2/99株的8个分节段基因进行扩增,分别将其克隆到pGEM-T easy载体后进行序列测定与同源性分析。结果CK/GS/2/99株PB2、PB1、PA、HA、NP、NA、M、NS基因的开放阅读框分别由2280、2274、2151、1683、1497、1401、759、864个碱基组成,分别编码759、757、716、560、498、466、252/97、231/122个氨基酸残基。该毒株HA上HA1和HA2裂解位点序列为PARSSR↓GLF,具有典型的低致病性禽流感病毒的特征。同源性分析显示,CK/GS/2/99株与1998-2002年间大部分中国大陆分离株遗传关系较近,尤其与CK/NX/4/99和CK/HB/31/00株遗传关系密切。结论CK/GS/2/99与大部分流行于中国内陆的H9N2亚型毒株均来源于共同的祖先毒株CK/BJ/1/94,这为了解中国H9N2亚型禽流感病毒的分子流行病学提供了资料。

Molecular charactiristics of the genome of H9N2 subtype avian influenza virus strain A/Chicken/Gansu/2/99

To elucidate the molecular characteristic and evolution status of avian influenza virus strain CK/GS/2/99,A strain of H9N2 avian influenza virus(CK/GS/2/99) isolated from the cloacal swabs of diseased chickens in Gansu province,8 genes of avian influenza virus strain CK/GS/2/99 were amplified by RT-PCR method.The genes were sequenced,and compared with the genome of referenced influenza viruses.The open reading frame(ORF) of PB2,PB1,PA,HA,NP,NA,M and NS of CK/GS/2/99 contained 2280,2274,2151,1683,1497,1401,759,864 nucleotides encoding 759,757,716,560,498,466,252/97,231/122 amino acids respectively.The amino acid sequence of the cleavage site between HA1 and HA2 is PARSSR↓GLF,with the typical characteristics of the low pathogenic avian influenza virus.The results showed high nucleotide and amino acid sequence identity between CK/GS/2/99 and most H9N2 subtype isolates in mainland China from 1998 to 2002,especially,CK/NX/4/99 and CK/HB/31/00.isolates in mainland China.This study lay a foundation to know the molecular epidemiology of H9N2 subtype avian influenza virus in China.