猪瘟病毒强弱毒株和野毒株E2全基因序列测定及比较分析

为了比较猪瘟病毒 (HCV)野毒株、疫苗株及标准株之间E2基因抗原区域的差异 ,采用RT PCR扩增了HCV石门株、兔化弱毒疫苗株、野毒 0 3及 0 7株的囊膜糖蛋白E2 (gp55)全基因的cDNA片段 ,分别克隆于pGEM T载体中并对其进行了核苷酸序列测定及氨基酸序列的推导 ,同时进行了同源性比较及E2结构与功能的分析。所测 4株HCVE2基因的长度均为1 2 73bp,所编码的氨基酸序列均包括部分信号肽序列和完整的跨膜区序列 ,共由 381个氨基酸组成 ;4个毒株E2蛋白N末端的 683位至 690位信号肽序列 (WLLLVTGA)和C末端 1 0 30～1 0 63位跨膜区均为保守序列 ,而且具疏水性 ;N末端抗原功能区中 ,4个E2蛋白与其它所比较序列在位于第 753位至 759位氨基酸处 ,均有一段保守序列RYLASLH ,无一氨基酸发生变异 ,为亲水性 ,在整个E2蛋白抗原谱中抗原性峰值为最高 ,推测对抗原性产生起重要作用 ;4个E2蛋白的氨基酸序列中均含有 1 5个半胱氨酸 (Cys)残基 ,其数量及位置与国外五株HCV(Brescia ,C ,Alfort.ALD和GPE)完全一致。表明…

SEQUENCING OF E2 GENE AND COMPARISON ANALYSIS OF FOUR STRAINS HOG CHOLERA VIRUS (HCV)

Four cDNA fragments of envelope glycoprotoin E2 gene of SM strain, HCLV strain, F03 strain and F07 strain were amplified respectively with RT-PCR method. The amplified E2 fragments of four HCV strains were all 1273 bp in length by agarose gel electrophoresis. Four E2 fragments were cloned respectively into pGEM-T easy vector. 1273 bp cDNA fragment of Four HCV E2 gene were sequenced and 381 residues amino acid sequence of E2 glycoprotein were deduced. The signal peptide sequence (WLLLVTGA) located in the N-terminal residues 683-690 and the transmenbrane region (TMR) sequence located in the C-terminal residues 1031-1063 of Four E2 gene were highly conserved and hydrophobic region. The conserved sequence among the E2 protein of pestiviruses, RYLASLH which located in the N-terminal residues 753-759 of domains B and C, was hydrophilic, and none of them were variable among the pestiviruses, and the greatest values of antigenic in all E2 antigenic domain. This suggest that the conserved sequence RYLASLH are involved in E2 epitopes. The number and locations of 15 cysteine residues in E2 are conserved among pestiviruses, suggesting that the structure of this glycoprotein is similar in pestiviruses and the first six cysteines are critical for the correct folding of E2 and essential for all identified epitopes. It is showed epitopes. between HCLV strains and field strains are not variable obviously by analysising the varintion of some main amino acid residuse substitutions of E2 major antigenic domains.