中国轮状病毒非结构蛋白NSP4基因变异特征的分析

目的　研究我国轮状病毒流行株NSP4基因的变异特点。方法　对近年来从我国不同地区获得的 2 7份人轮状病毒流行株的NSP4基因用RT PCR进行扩增 ,克隆后进行全长cDNA序列分析 ,并利用Clustal× 1.8,TreeView3 2及DNAStar软件与参比株Wa、KUN、AU 1、EW及来自GenBank的OSU、SA11、Hochi、US2 44、Bristol株的NSP4序列进行分析比较。采用PCR分型方法对VP7血清型进行鉴定 ,确定轮状病毒G型与NSP4基因型的关系。结果　氨基酸同源性比较表明 ,我国轮状病毒不同流行株NSP4之间同源性为 81.7%～ 99.4% ,据此可将 2 7株RVNSP4分为 2组 ,分别以Wa株和KUN株为代表 ,其中以Wa组为主。组内同源性分别为 92 .0 %～ 99.4%和 92 .0 %～ 98.9% ,组内变异率分别为 0～ 8 5 %及 1 2 %～ 8 5 %。两组间变异率达 16 6%～ 2 1 0 %。氨基酸进化树提示在Wa组内包括 3个亚组。轮状病毒G血清型与NSP4基因型之间的联系不确定。结论　我国流行株NSP4基因主要可分为Wa组和KUN组 ,在Wa组内可形成三个亚组 ,并且在高变区有特征性的氨基酸位点。NSP4的变异与年份有关而与地域关系不密切

Genetic characterization of the non-structural protein NSP4 from epidemic strains of human rotavirus in China

BACKGROUND: To clarify the features of gene variation among epidemic strains of human rotavirus NSP4 in China. METHODS: SP4 genes from 27 epidemic strains of human rotavirus isolated in different area of China in recent years were amplified with RT-PCR, the resulted cDNAs were cloned and sequenced. The sequences of full length cDNAs were compared with 10 rotavirus NSP4 sequences available in the GenBank using the Clustal x 1.8 TreeView32 and DNA Star softwares. The G serotype of VP7 was analysed by PCR. RESULTS: The homology of the amino acid among the 27 rotavirus strains isolated in China was 81.7%-99.4%. Based on the variation of amino acid sequence, the virus strains can be divided into two groups, represented by Wa and KUN with the homology of 92.0%-99.4% and 92.0%-98.9% within each group, respectively. The diversity between the two groups were 16.6%-21.0%. The Wa group could further be separated into three subgroups, according to the diversity between those strains and the characterization in the highly variable domain. The association between VP7 serotype and NSP4 genotype was not strong. CONCLUSIONS: The NSP4 gene of human rotavirus epidemic strains in China can be divided into Wa and KUN two groups, Wa group is the main group and contains three subgroups possessing characteristic amino acid sites. Samples isolated in the same year but not in the same area shared higher homology.