河南牛、鼠源狂犬病毒G基因主要功能区的比较分析

COMPARISION AND SEQUENCING OF G GENE ECTODOMAINBETWEEN RABIES VIRUSES BRV(FROM CATTLE)AND MRV(FROM MOUSE)ISOLATED IN HENAN

本研究对从我国河南牛狂犬病疫区分离的狂犬病病毒牛源毒ＢＲＶ和鼠源毒ＭＲＶ的糖蛋白（Ｇ）基因膜外主要功能区进行反转录—聚合酶链反应（ＲＴ－ＰＣＲ）扩增、克隆、测序和两者的比较分析。分别得到了每个毒株Ｇ基因膜外区７４２ｂｐ的ｃＤＮＡ片段（位于Ｇ基因４０５～１１４６号碱基）和推导的氨基酸序列，它含有可以诱导产生中和抗体的多个抗原决定簇和决定毒力及与神经细胞受体结合位点。计算机的比较分析表明两者在这一基因片段的同源性很低，核苷酸和氨基酸序列的同源性分别为８１．１％和８５．４％，主要抗原决定簇ＡｇⅡ的２０２位和ＡｇⅢ的３３２位氨基酸两者不同，并且ＭＲＶ在２０２位形成糖基化位点。研究结果证明ＢＲＶ和ＭＲＶ是亲缘关系较远的毒株，甚至有型或亚型的差别，两者的核苷酸和氨基酸序列均有较大差异，ＢＲＶ不可能是ＭＲＶ在短时间内演化而来的毒株。

オhe main regions in glycoprotein(G)gene of BRV and MRV,isolated from cattle and mouse in Henan rspectively,of Rabies virus are amplified by reverse transcriptase—polymerase chain reaction(RT—PCR),cloned and sequenced.The fragments which are responsible for the induction of neutralization antibodies,the virulence,the combination of virus with the receptor of nerve cell,are 742 bp nucleotides(range from 405 to 1146)in ectodomain segment of G gene.Comparision of the cDNA sequence and deduced amino acid sequence of BRV and MRV are performed by computer with DNA SIS software.The results show their homology of cDNA sequence or deduced amino acid sequence are very low(81.1% and 85.4%).The amino acids(202 and 332 sites)in main antigen sites and potential glycosylation sites of them are different.Therefore,it is suggestted that BRV could not be from MRV in short period and might belong to different genetic types.