广西狂犬病野毒株N和G基因的克隆与序列分析

Cloning and Sequencing of N and G gene of rabies virus strains isolated from Guangxi

从广西南宁、隆安和巴马分离到三株狂犬病病毒野毒株,分别编号为GXN119、GXLA和GXBM。对三株的N基因和GXN119、GXBM株的G基因进行了RT-PCR扩增、克隆和测序。将测序所得结果和收集到的国内外已发表毒株相应基因进行了核苷酸和推定氨基酸的序列进行比较分析。三株野毒之间N基因的核苷酸同源性分别为:89.1%(GXN119/GXBM)、89.7%(GXN119/GXLA)和89.4%(GXLA/GXBM),G基因的核苷酸同源性为86.7%(GXN119/GXBM)。比较N基因推导氨基酸序列同源性,分别为:97.8%(GXN119/GXBM)、97.8%(GXN119/GXLA)和99.1%(GXLA/GXBM),表明N基因同义变异较多。将两株野毒株GXN119、GXBM与人用疫苗3aG株和兽用疫苗ERA株的G基因进行了核苷酸序列比较,同源性介于82.7%～84.0%之间,推定氨基酸同源性在88.0%～91.6%之间。N蛋白的第40位Ser和106位Asp显示了广西狂犬病流行病学的区域特异性。

Three wild strains of rabies virus were isolated from Nanning,Longan and Bama of Guangxi and which were designated as GXN119, GXLA and GXBM respectively. The nucleoprotein(N) gene of three strains and glycoprotein(G) gene of two strains GXN119、GXBM were amplified by reverse transcription-polymerase chain reaction(RT-PCR), respectively. The RT-PCR products were cloned into pMD18-T vector and then sequenced. The sequences of N and G gene and their deduced amino acid sequences were compared and analyzed with that of some other rabies virus strains published previously. The nucleotide homology of N gene among three street strains were 89.1 %(GXN119/GXBM), 89.7 %(GXN119/GXLA) and 89.4 %(GXLA/GXBM)respectively,and the nucleotide homology of G gene between two street strains were 86.7 %(GXN119/GXBM).But the homology of deduced amino acid sequence of N gene among the three strains were 97.8 %(GXN119/GXBM),97.8 %(GXN119/GXLA) and 99.1 %(GXLA/GXBM),respectively,considering that the changes were mainly synonymous mutations in N gene. Comparison of the G gene of GXN119 and GXBM with that of 3aG and ERA, the homologies of nucleotide were ranged from 82.7 % to 84.0 %,and the homologies of amino acid were 88.0 % to 91.6 %. Amino acids of the position 40 and 106 on N protein are Ser and Asp respectively, showed the regional specific mutations of rabies virus in Guangxi.