[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.