GII.P21/GII.3型重组诺如病毒的分子特征分析

Analysis on the molecular characteristics of GII.P21/GII.3 recombinant norovirus

目的对两株GII.P21/GII.3型重组诺如病毒的主要基因片段进行扩增,并对其分子特征进行初步分析.方法利用普通RT-PCR对两个毒株的部分聚合酶区及完整衣壳蛋白区片段进行扩增和序列测定.通过BioEdit及MEGA软件进行序列比对及进化分析,Simplot软件进行重组位点分析.结果序列分析显示,2株诺如病毒在聚合酶区与衣壳蛋白区均和2009—2011年的越南株处于同一小的分支,该分支毒株间的相似性分别为97.3%~98.9%及96.8%~98.1%;可能的重组位点在第701位核苷酸,位于病毒的开放读码框架1上;各簇毒株均出现不同程度的氨基酸位点突变,3个受体结合位点及两个抗原位点无变异,但与受体结合位点II相邻的氨基酸385位点出现了变异.结论江苏省存在GII.P21/GII.3型诺如病毒的感染.

Objective To explore prelimilarily the molecular characteristics of two strains of GII.P21/GII.3 recombinant norovirus by amplifying the main gene fragments. Methods The fragment of RNA-dependent RNA polymerase (RdRp) gene and the complete capsid protein gene of both strains were amplified by RT-PCR and were sequenced. Bioedit and MEGA softwares were used for sequence alignments and phylogenetic analysis. The recombinant breakpoints were analyzed by Simplot software. Results Sequence analyses of RdRp and capsid protein genes indicated that both stains located in the same branch with Vietnamese strains from 2009 to 2011, and the similarities of the strains in this branch were 97.3-98.9% and 96.8-98.1%, respectively. The possible recombinant breakpoint was detected at nucleotide position 701, localized in the open reading frame 1 of the virus. The amino acid substitutions were observed in all clusters of viruses at varying degrees. Although no amino acid substitution was observed in three receptor binding sites and two antigenic sites, a mutation at amino acid position 385 near the receptor binding site II was found. Conclusions The study indicated that norovirus genotype GII.P21/GII.3 existed in Jiangsu Province.