Abstract: In order to construct the recombinant prokaryotic expressed vector of the heavy chain of SLA-1 derived from Topigs pig and to study its expression in pET-21a(+), a pair of primers was designed to amplify the extracellular domain of SLA-1-TPK gene(named SLA-1-TPKe)followed by sub-cloning the gene into pMD19-T Simple Vector. After identification by cleavage with Nde I and Xho I, the SLA-1-TPKe was ligated to pET-21a(+)and transformed into BL21(Rosseta)to be induced to express followed by analysis of the expressing products by SDS-PAGE. Finally, the inclusion bodies of the SLA-I-TPKe was isolated and detected by SDS-PAGE. The PCR result was shown that the length of the SLA-1-TPKe was about 851 bp which was consistent with the calculated value. Then, the SLA-1-TPKe was successfully cloned into the pMD19-T Simple Vector and identified by cleavage with Nde I and Xho I and the inserted fragment was about 831 bp. In succession, the gene was successfully inserted into pET-21a(+)followed by transforming into Escherichia coli BL21(Rosseta). After induction and expression, the SLA-1-TPKe was successfully expressed with the interest of protein about 31 kD. The protein was expressed mainly as inclusion body protein with the purity of 90%.

Key words: Topigs pig, SLA-1, the heavy chain gene, expression, inclusion protein