2011—2017年四川省狂犬病病毒N、G基因序列测定与分析

Sequencing analysis of N and G gene of rabies viruses from Sichuan province of China in 2011- 2017

目的了解四川省2011—2017年间狂犬病病毒(rabies virus,RABV)株的分子特征以及流行株与疫苗株在核酸、氨基酸和蛋白修饰水平上的差异.方法对采集于2011—2017年间的23份RABV抗原阳性犬脑组织标本,通过RT-PCR以特异性引物扩增病毒核蛋白(nucleoprotein,N)基因和糖蛋白(glycoprotein,G)基因并测序,通过生物信息学软件分别对N基因和G基因进行基因特征分析.结果对23株RABV(简称四川株)N、G基因测序获得的全序列遗传进化关系分析表明,四川株均为rabies virus种,可分为3个进化分支且具有明显的地域特征,部分四川株与我国东部和北方流行毒株共循环.四川株间N基因的核苷酸和氨基酸同源性分别为97.4%~100%和99.6%~100%,与参考株N基因的核苷酸和氨基酸同源性分别为72.1%~99.8%和81.6%~100%.四川株与疫苗株相比在抗原位点、细胞表位以及信号肽序列上有一定差异,但主要抗原性、组织嗜性和毒力没有改变.结论四川株间无明显差异,均为rabies virus种.四川株与疫苗株病毒糖蛋白的氨基酸序列存在不同程度的差异,但毒力未发生改变.

Objective To analyze molecular feature of rabies virus (RABV) epidemic strains in Sichuan province during 2011 to 2017, and explore differences at nucleotide, amino acid and protein modification between these street strains and vaccine strains. Methods Nucleoprotein( N) and glycoprotein (G) genes were amplified by RT-PCR using specific primers for 23 antigen?positive canine brain specimens collected from 2011 to 2017. The evolutionary relationship and immune antigenicity of N and G genes was analyzed. Bioinformatics software was used to analyze and organize data. Results We obtained the N and G genes sequences of 23 RABV strains by sequencing. Genetic evolution relationship analysis showed that all the 23 RABV strains belonged to rabies virus species and could be divided into three branches, which had apparent geographically specific characteristics but some Sichuan strains co-circulated with the epidemic strains in the eastern and northern regions of China.The N genes of Sichuan strains had nucleotide and amino acid homology of 97. 4% to 100% and 99. 6%-100%. The nucleotide and amino acid homology between Sichuan strains and reference strains were 72. l%-99. 8% and 81.6%-100%, respectively. There were some differences in antigenic sites, cell epitopes and signal peptide sequences between vaccine strain and Sichuan strains but no significant change was found in antigenicity, organizational preference and virulence. Conclusions The 23 strains of RABV of Sichuan belonged to rabies virus species and had no obvious differences. There were few differences between Sichuan strain and vaccine strain in amino acid sequences of G, but the virulence did not change.