诺如病毒GII.4型济南JN010株基因组特征分析

Genomic sequences analysis of human Norovirus GII.4 variant JN010 in Jinan

目的分析诺如病毒(Novirus, NoV)GII.4型济南JN010株基因组序列及其特征。方法根据文献并结合PrimerSelect软件设计7对引物,利用RT-PCR方法获得NoV济南JN010株全基因组序列,应用Lasergene7.1、MEGA5.2等软件对基因组序列进行遗传进化、同源比对分析,建立ORF1及ORF2基因系统进化树。并根据VP1氨基酸序列进行突变分析。结果NoV JN010株基因组序列全长7 516 bp,为GII.Pe/GII.4基因型,属于GII.4 Sydney 2012变异株。突变位点主要发生在VP1的P2区,其中抗原表位A及与组织血型抗原(histo-blood group antigens,HBGAs)结合位点A处发生R297H突变,毗邻抗原表位A位点发生I293N和H373N突变。根据ORF1基因序列,JN010株与日本Osaka源病毒株(GenBank登录号LC066046)亲缘关系较近;根据ORF2基因序列,与广东中山源病毒株(GenBank登录号KY407064)亲缘关系较近。结论NoV JN010株VP1在抗原表位A及与HBGAs结合位点发生突变,可能影响其抗原性及与HBGAs结合的特异性。

Objective To analyse the genomic characteristics of Novirus(NoV) GII.4 genotype JN010 strain isolated form Jinan in 2017. Methods Seven pairs of primers were designed and used to amplify the JN010 genome. Sequence analyses, alignment and phylogenetic trees of ORF1 and ORF2 genes were performed using the software Lasergene7.1 and MEGA5.2. At the same time the major protein VP1 amino acid mutations were analyzed. Results The 7 516 bp complete genome sequence of JN010 strain was obtained, the most mutation sites were located in P2 subdomain of VP1. Two substitutions I293N and H373N of VP1 were locate neighboring epitope A, and R297H mutation happened within epitope A and the site A that binding with histo-blood group antigens(HBGAs). The JN010 strain was GII.Pe/GII.4 genotype and genetically closest to the strains found in Osaka of Japan(GenBank accession number LC066046) and the strains in Zhongshan city of Guangdong (GenBank accession number KY407064) respectively according to ORF1 and ORF2 gene homologous and phylogenetic analysis. Conclusions The NoV GII.4 variant strain JN010 has occurred mutations in the key site of the epitope A and site A that bind with HBGAs, and maybe affect its antigenicity and interaction with HBGAs.