Abstract: A pair of primers was designed according to the porcine follistatin(FS) gene mature peptide sequence(GenBank:M36512.1), the mature peptide sequence of FS gene was achieved by PCR. The PCR product of the expected length was cloned into the pMD18-T vector and transformed into E.coli DH5α. The positive clones were identified by PCR, enzyme digestion and sequencing. Then insert the FS gene mature peptide between the BamHⅠ and HindⅢ sites of the pRSET-A vector generating the recombinant plasmid pR-FS and transformed it into E.coli BL21(DE3). The positive clones were also identified by PCR, enzyme digestion and sequencing. Bacteria transformed by pR-FS were expressed in E.coli BL21(DE3) after induction with IPTG and produced a product showing expected molecular mass of 26.1 ku in SDS-PAGE, which achieved the highest level induced by 0.2 mmol/L IPTG for 3 h. The product can be purified by 50% Ni-NTA agarose. These results demonstrated that the porcine FS gene mature peptide sequence was successfully cloned and expressed in E.coli BL21(DE3).

Key words: follistatin; mature peptide sequence; cloning; expression