[Cloning and expression of Mycobacterium bovis secreted protein MPB51 in Escherichia coli].

ABSTRACT

The gene encoding MPB51 was amplified from M. bovis Valleel11 chromosomal DNA using PCR technique, and the PCR product was approximately 800 bp DNA segment. Using T-A cloning technique, the PCR product was cloned into pGEM-T vector and cloning plasmid pGEM-T-51 was thus constructed successfully. pGEM-T-51 and pET28a( + ) were digested by BamH I and EcoR I double enzymes. The purified MPB51 gene was subcloned into the expression vector pET28a( + ), and the prokaryotic expression vector pET28a-51 was thus constructed. Plasmid containing pET28a-51 was transformed into competence E. coli BL21 (DE3). The bacterium was induced by IPTG and its lysates were loaded directly onto SDS-PAGE, approximately 30 kD exogenous protein was observed on the SDS-PAGE. The protein was analyzed using Western blot. The results indicate that the protein is antigenic activity of MB. The results are expected to lay foundation for further studies on the subunit vaccine and DNA vaccine of MPB51 gene in their prevention of bovine tuberculosis.