Construction of the recombinant expression plasmid encoding Ag85B genee of the tuberculos is bacter ium

Objective To clone and construct a expression plasmid containing Ag85B,gene of tuberculosis bacterium.Methods Ag85B gene of tuberculosis bacterium was amplified (PCR method)from the H37Rv,the Ag85B gene contained 978bp,then cloned into pGEM-T-easy vector,finally,subcloned into pGEX-4T-2 according to its special orientation.The constructed recombinant plasmid was transferred to E.coli DH5α.The positive clone was identified by restriction analysis and DNA sequencing.Results The size of the Ag85B gene digested by endoenzymes was 978bp.The sequence was the same with t he sequence reported on the literatures.Conclusion The Ag85B gene was successfully amplified and cloned into pGEX-4T-2 expression vector.