论文部分内容阅读
目的探究1株新分离的基因Ⅰ型乙脑病毒株的分子生物学特征及其低毒力的分子基础。方法对病毒株扩增,提取其RNA,逆转录PCR后测序,序列与来自世界不同地区不同基因型的野毒株进行同源性比较,并与强毒P3株进行氨基酸位点比对。结果SC04-17在核苷酸和氨基酸序列上,存在与其他基因型毒株不同的特点,与世界各地毒株核苷酸差异率为1.8%～16.5%,氨基酸差异率为0.8%～5.0%;与减毒活疫苗株SA14-14-2的核苷酸、氨基酸同源性分别为88.5%和97.6%,与灭活疫苗株P3核苷酸、氨基酸同源性分别为88.8%和97.9%;与P3强毒株比对,发现72个氨基酸位点差异,分布在全基因的各个区域(E、NS5、NS1和NS3区)。结论SC04-17株的基因序列存在一些独特位点,这些位点的氨基酸变化可能与其低毒力特征有关。
Objective To investigate the molecular biological characteristics of a newly isolated genotype I JE virus and its molecular basis for low virulence. Methods The viral strains were amplified and their RNAs were extracted. After reverse transcriptase PCR, the sequences were compared with wild type strains from different genotypes in different regions of the world. The homology was compared with that of virulent strain P3. Results The nucleotide and amino acid sequences of SC04-17 were different from those of other genotypes. The nucleotide variation rates of SC04-17 varied from 1.8% to 16.5% with amino acid variation rates of 0.8% -5.0% . The nucleotide and amino acid homologies of the attenuated live vaccine strain SA14-14-2 were 88.5% and 97.6%, respectively. The nucleotide and amino acid homology of P3 with inactivated vaccine strain was 88.8% and 97.9% ; Compared with the virulent strains of P3, 72 amino acid residues were found in all the regions of the whole gene (E, NS5, NS1 and NS3). Conclusion There are some unique loci in SC04-17 strain. The amino acid changes of these loci may be related to their low virulence.