Abstract: To express N-terminal major epitope domain of ORF2 of swine hepatitis E（SHEV) in E.coli. According to the amino acid sequence of SHEV DQ1 strain in GenBank, N-terminal major epitope domain in ORF2 was primarily mapped upon analysis of bioinformatic software. A pair of specific primer was designed to amplify the fragment encoding the major epitope domain. This fragment was cloned into the multiple cloning sites of pET30a (+) vector after subjecting to restriction endonuclease digestion. The recombinant plasmid was designated pET30a-ORF2N and was transformed into E.coli BL21 competent cells. Expression of recombinant protein was induced by addition of final concentration of 1.0 mmol/L IPTG under 37 ℃ condition. The length of RT-PCR product of interest is 424 base pairs. The size of recombinant amino acid deduced is 21.8 ku in theory. The result of Western blotting showed that the recombinant protein specifically reacted with serum against SHEV, suggesting the recombinant protein had wonderful specificity. N-terminal major epitope domain of ORF2 of SHEV was expressed successfully in E. coli and showed specificity. It can be used as antigen in diagnostic assay for measuring antibodies against SHEV in clinical practice.

Key words: swine hepatitis E; ORF2; major epitope domain; expression