| 摘要: |
| [目的]对H9N2禽流感病毒HA基因全序列进行分析,了解H9N2禽流感分离毒株HA基因的遗传变异情况.[方法]根据GenBank已发表的H9N2毒株的基因序列,设计了2对H9N2禽流感病毒HA基因特异性引物,运用RT-PCR方法对XL、LF和WN分离株进行了扩增,然后将PCR产物送出进行测序,用DNAstar 5.0软件对测序结果进行了分析.[结果]XL、LF和WN 3株H9N2分离株间HA基因的核苷酸同源性为99.7%～99.9%,推导氨基酸的同源性为99.1%～99.6%;分离株与参考毒株HA基因核苷酸的同源性为96.2%～99.0%,推导氨基酸的同源性为96.2%～98.6%.通过对3个H9N2分离株间HA基因核苷酸序列的比较,发现共有5个位点的核苷酸发生突变,其中4个位点核苷酸的改变导致相应的氨基酸发生突变.HA蛋白的7个受体结合位点比较保守,但是其在551～553位缺失了潜在的糖基化位点.[结论]3株H9N2分离株裂解位点氨基酸序列完全符合低致病性禽流感的特征 RSSR↓G,但是LF裂解位点附近333位脯氨酸(Pro)突变为组氨酸(His),即非极性氨基酸向极性带正电氨基酸(碱性氨基酸)转变,裂解位点的变化可能是H9N2禽流感病毒生物学特性改变的分子基础. |
| 关键词: 禽流感病毒 HA基因 遗传变异分析 |
| DOI： |
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| 基金项目:陕西省科技攻关项目 |
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| Genetic variation analysis of HA gene of H9N2 Avian Influenza Virus isolates from Shaanxi Province |
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| Abstract: |
| 【Objective】 The study investigated the genetic variation of H9N2 Avian Influenza Virus(AIV) isolates. 【Method】 According to the nucleotide sequences of HA gene of H9N2 AIV,two pairs of primer were synthesized and used to amplify the HA gene of XL,LF and WN isolates by RT-PCR using genome RNA as template.The three products of PCR were sequenced,then the three sequences were analysed by using software of DNAstar 5.0. 【Result】 Results showed that nucleotide homology of HA gene among the three isolates were at the range of 99.7%－99.9%,and amino acid homology was 99.1%－99.6%.The nucleotide homology and amino acid homology between isolated strains and the reference strains were 96.2%－99.0% and 96.2%－98.6% respectively.In comparison,five nucleotide sites mutated,of which four nucleotide site variations led to the mutation of corresponding amino acid sequences. Seven receptor binding sites of HA protein were comparatively conservative,while potential glycosylation sites were deleted in 551－553 amino acids. 【Conclusion】 The amino acid sequences at the three H9N2 isolates cleavage sites were completely constant with the unique rule of mildly pathogenic avian influenza-RSSR↓G.The 333 amino acid (Proline) near the LF cleavage site turned into Histidine.Therefore,the alteration from nonpolar amino acid to electropositive polar amino acid and variation of cleavage sites may be the molecular basis of biological characteristics variation of H9N2 AIV isolates. |
| Key words: Avian influenza virus(AIV) H9N2 HA gene genetic variation analysis |
