狂犬病病毒糖蛋白基因主要功能区的克隆和序列比较分析

Comparison and Sequence Analysis of G Ectodomain of Rabies Virus Strains from Different Animals in China

对我国不同来源的狂犬病野毒株８２０２、ＢＲＶ、ＭＲＶ以及无毒疫苗株ＳＲＶ９的Ｇ基因４０５～１１４４位核苷酸序列进行了ＲＴ－ＰＣＲ扩增、克隆和序列测定，并应用计算机对其进行了分析比较。结果证明，鹿源８２０２株与中国人用疫苗株为同源株（同源性达９７．０％），因此我国鹿狂犬病极可能是人用疫苗毒株污染所致；同地不同动物分离的ＭＲＶ株和ＢＲＶ株为亲缘关系较远毒株，表明ＢＲＶ引起的牛狂犬病不是由于ＭＲＶ感染所致；疫苗株ＳＲＶ９与３个野毒株同源性在８３％～８４％之间。３个野毒株８２０２、ＢＲＶ、ＭＲＶ及疫苗株ＳＲＶ９的糖基化位点和抗原决定簇内某些氨基酸亦不同。由计算机建立的系统树首次证明我国存在着狂犬病病毒基因亚型。８２０２、ＭＲＶ、ＳＲＶ９和其他对照株的同源性在８５．３％以上，为Ⅰａ亚型；ＢＲＶ与它们的同源性仅为８２．３％，被分为Ⅰｂ亚型。

The main regions ranging from 405 nt to 1 144 nt of glycoprotein (G) ectodomain gene of rabies virus strains 8202, BRV, MRV, isolated from deer, calf, mouse in various areas of China respectively, and vaccine strain SRV 9 were amplified by RT PCR. Then they were cloned and sequenced by sanger′s method. Comparison and analysis of the deduced nucleotide sequence and amino acid sequence with that of other 8 strains previously published was performed by computer with DNASIS software. The results showed that the nucleotide sequences and potential glycosylation sites of four sequenced strains were different. The homology of 8202 and RAVVSGP is the highest (97.0%). The results suggested that rabies virus of deer may be diverged from Chinese vaccine strain RAVVSGP. The fact that homology of BRV and MRV is only 81.1% showed that these two strains both isolated from Henan area were different in G ectodomain gene. The homology of the amino acid sequence of SRV 9 with 3 street strains 8202, BRV, MRV was between 83%￣84%. A phylogenetic tree was established by analysis on 740 nt in G ectodomain gene of 12 different rabies strains. All of the strains except strain Mokola that was genotype Ⅲ were classified in genotype Ⅰ and may be further divided into two sub genotype Ⅰa and Ⅰb. Genotype Ⅰa includes 8202, BRV, SRV 9 and other strains used as control in the present study. Genotype Ⅰb includes only BRV and its homology with other strains is 82.3%. This result proved that rabies viruses from China could be divided into different sub genotypes.