我国近期7株猪瘟流行野毒E2基因变异研究

Study on Mutation of E2 Gene of Seven Recent Prevalent Field Strains of CSFV in China

应用RT-PCR和nPCR扩增了7株国内近期(2001年-2003年)流行的猪瘟野毒E2基因,分别克隆至pGEM-T载体并对其进行了核苷酸序列测定及氨基酸序列推导,同时将其与C株、Alfort株、Brecsia株进行了同源性比较及遗传进化分析,构建了CSFV的遗传发生树,并对E2结构与功能进行了分析.所测7株野毒均包括完整的信号肽序列及部分跨膜区在内的1 170 bp,与C株、Alfort株、Brescia株核苷酸序列同源性分别为91.6%～94.5%、89.2%～92.7%、85.9%～89.3%,氨基酸同源性分别为91.2%～95.8%、88.9%～92.0%、84.0%～90.1%;而7株野毒之间的差异很小,其核苷酸序列同源性为95.8%～99.7%,氨基酸同源性为96.3%～99.1%.所绘制的遗传发生树分为2个组群,所测得7株流行野毒均属于第1群,而且可分为两亚群,与C株在同一亚群.同时对主要抗原区氨基酸位点变异进行了分析,对其抗原决定簇的变异情况进行了推测.

In this study, the 1.17kb fragments of E2 gene of seven recent prevalent field strains of classical swine fever virus that had been collected from different province were amplified by RT-PCR and cloned into pGEM T vector.Their nucleotide sequences were determined and the amino acid sequences were deduced. Compared with the corresponding region of C, Alfort and Brescia strain of CSFV, the nucleotide sequence homologies were 91.6%~94.5%, 89.2%~92.7% and 85.9%~89.3% respectively, the amino acid homologies were 91.2%~95.8%, 88.9%~92.0% and 85.9%~89.3% respectively. But the homologies among the seven field strains were very higher, their nucleotide sequence homologies and amino acid homologies were 95.8%~99.7%, 96.3%~99.1% respectively. The further study of these field strains heredity relationship was done by the phylogenetic tree, all the sequenced strains belong to the Group I, and the seven strains can apparently be divided into two subgroups. What this paper showed does not accord with the prevalent opinion that the genetic variation of CSFV was diversity.