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目的 对北京市GⅡ.P16-GⅡ.2型诺如病毒变异株进行全基因组序列扩增及进化分析,了解其基因遗传变异特征.方法 采用一步法反转录聚合酶链反应,对2017年北京发现的两株GⅡ.P16-GⅡ.2诺如病毒进行全基因组序列分段扩增及测序,利用DNAStar 7.0、BioEdit进行序列拼接,采用Mega 5.05软件以最大似然法构建进化树,采用SimPlot软件进行相似性分析,并分析其组织血型抗原结合位点及附近氨基酸变异情况.结果 全基因组及衣壳蛋白区进化树分析显示,北京市2017年发现的两株诺如病毒与其他2016-2017年出现的GⅡ.P16-GⅡ.2型诺如病毒单独形成一个分支.聚合酶区进化树分析显示,这两株病毒与其他2016-2017年的GⅡ.P16-GⅡ.2型、2015-2016年的GⅡ.P16-GⅡ.4 Sydney 2012型混合形成一个分支.与2016年以前的GⅡ.P16-GⅡ.2型诺如病毒相比,衣壳蛋白区及聚合酶区序列进化树分析提示,GⅡ.P16-GⅡ.2 2016-2017与201 1年该型诺如病毒分离株进化距离更近.氨基酸序列比较发现,两株病毒组织血型抗原结合位点附近的氨基酸与其他该型别诺如病毒相比,各有一处点突变.结论 北京市2017年发现的两株诺如病毒经全基因分析证实为GⅡ.P16-GⅡ.2型重组株,并且有可能是从2011年发现的GⅡ.P16-GⅡ.2型诺如病毒进化而来.“,”Objective To amplify the complete genomes of two noroviruses (NoVs) GⅡ.P16-GⅡ.2 variants in Beijing,2017 and to analyze the genetic characteristics of the strains.Methods The complete genome sequences of the two GⅡ.P16-GⅡ.2 NoVs strains were amplified by one-Step RT-PCR,and the PCR products were sequenced.The sequences were assembled by the DNAStar 7.0 and BioEdit,and the phylogenetic trees were generated using the maximum-likelihood method by Mega 5.05.The SimPlot software was used for similarity analysis.The amino acid mutations within or near histo-blood group antigen (HBGA) binding site were also analyzed.Results Both NoVs strains detected in Beijing formed a new cluster frow other GⅡ.P 16-GⅡ.2 2016-2017 strains in the phylogenetic trees of the complete genome sequences and VP1 sequences.However,the two strains,other GⅡ.P16-GⅡ.2 2016-2017 strains and GⅡ.P16-GⅡ.4_Sydney 2015-2016 strains formed a mixed branch in the phylogenetic tree of RDRP.The phylogenetic trees of the VP1 sequences and RDRP also indicated that the GⅡ.P16-GⅡ.2 2016-2017 strains were the closest to the strains in 2011,comparing to those found before 2016.Both strains had one amino acid mutation nearing HBGA binding site comparing to other GⅡ.P16-GⅡ.2 strains.Conclusions The two NoVs strains detected in Beijing in 2017 were confirmed to be GⅡ.P16-GⅡ.2 recombinant strains by complete sequence analysis,and they may originated from GⅡ.P 16-GⅡ.2 strains in 2011.