我国四株狂犬病毒糖蛋白基因序列分析和位点比较

Sequencing and Position Analysis of the Glycoprotein Gene of Four Chinese Rabies Viruses

测定我国人用狂犬疫苗株 (aG)、减毒株 (CTN 181)及两株街毒糖蛋白 (GP)基因cDNA的核苷酸序列及推导氨基酸序列。结果两株街毒仅相差两个碱基和一个氨基酸残基 ;两株街毒与CTN的同源性 (85.9% )高于aG株 (81.9% ) ;聚类分析将街毒和固定毒分为两支。比较GP嗜神经位点的氨基酸序列与蛇神经毒素同AChR结合部位高度同源。被认为决定毒力的 333位Arg ,CTN发生了Q替换 ,其它毒株均为Arg333。所比较的毒株均存在 319位糖基化位点 ,此外 37位糖基化位点也相对保守 ;GP两个主要抗原表位 ,GⅡ的氨基酸构成完全一致 ,GⅢ只在一些减毒株中发生与毒力密切相关碱基的替换。

The glycoprotein gene of human rabies vaccine strain (aG), one attenuated fixed strain (CTN 181) and two street viruses were sequenced and the amino acid sequences were deduced. The result shows that two street strains have two differences in nucleotide sequences and one in amino acid sequences, the nucleotide homology was higher compared with CTN (85.9%) than with aG (81.9%). Phylogenetic tree divided the street strains and the laboratory strains into two branches. High amino acid sequence similarity was present between the segments of the viral GP which may function as a recognition site for AchR and the receptor binding region of the neurotoxins; CTN strain had Q substitution at position 333 and the other virulent strains preserved 333 Arg. In all strains 319 glycosylation was existed, glycosylation on 37 is also relatively conserved. The amino acid constitution of antigenic site Ⅱ is identical in all compared strains, but on site Ⅲ some attenuated strains have amino acid substitution on position 333 and other sites which related with pathogenicity.