广西流行的猪瘟病毒株E2基因序列测定及分析

目的对广西流行的猪瘟病毒E2基因进行序列测定及分析。方法应用PCR对15株猪瘟病毒E2基因进行扩增、克隆及测序,利用DNAstar分析软件对所测定的15株毒株与兔化弱毒(HCLV)、石门(Shimen)毒株的相应基因片段进行同源性分析。结果得到长度为1092nt猪瘟病毒E2基因,编码364个氨基酸残基的目的基因片段。广西株与HCLV、Shimen株的核苷酸同源性分别为81.5%～82.8%和82.8%～84.3%,推导的氨基酸同源性分别为87.1%～88.8%和88.5%～89.9%,广西毒株之间核苷酸与推导的氨基酸同源性分别为92.3%～99.9%和94.8%～100%。广西15株猪瘟病毒E2蛋白上的全部半胱氨酸(Cys)位点均未改变,推测其E2蛋白的抗原结构保持很高的稳定性。但广西毒株中与特定单克隆抗体结合的724、725、729、734和738位的氨基酸发生了变异,这些变异可能导致不完全免疫保护。把所测定的广西15株与国内外已发表的19株病毒相应序列进行比较,建立系统发育树,所比较的34株猪瘟病毒被分为两个群,广西毒株皆属于基因群Ⅱ。结论成功进行了广西流行猪瘟病毒E2基因序列分析,为进一步探讨猪瘟病毒E2蛋白的抗原结构提供了依据。

E2 Gene Sequence of Classical Swine Fever Virus Epidemic in Guangxi, China

Objective To analyze the E2 gene sequence of classical swine fever virus(CSFV) in Guangxi,China.Methods A total of 15 strains of classical swine fever virus isolated from various regions of Guangxi(GX) were amplified by RT-PCR,cloned and sequenced.The homologies of the 15 GX strains to hog cholera lapinised virus(HCLV) and Shimen strain were analyzed by DNAstar software.Results The E2 gene,at a length of 1 092 nt,encoding 364 amino acids was amplified.The homologies of nucleotide sequence of GX strain to HCLV and Shimen strains were 81.5%-82.8% and 82.8%-84.3%,and those of deduced amino acid sequence were 87.1%-88.8% and 88.5%-89.0%,respectively.However,the homologies of nucleotide and amino acid sequences of the 15 strains were 92.3%-99.9% and 94.8%-100% respectively.No change was observed in any Cys site of E2 protein of the 15 GX strains,so the antigen structure of E2 protein was highly stable by inference.However,the variations of amino acids were observed at sites 724,725,729,734 and 738 for binding to specified monoclonal antibodies,and might induce incomplete immune protection.The sequences of 15 GX strains were compared with those of 19 strains reported,and a phylogenetic tree was constructed.According to the phylogenetic tree,the 34 strains were classified as 2 groups.All the GX strains belonged to genotype Ⅱ.Conclusion The E2 gene of classical swine fever virus epidemic in Guangxi,China was successfully sequenced.It provided a basis for further study on the antigenic structure of E2 protein.