To amplify ESAT-6 gene of Mycobaterium tuberculosis and construct E.coli-Mycobacterium shuttle plasmid ps3000-ESAT-6 and recombinant M.smegmatis mc2 155. The ESAT-6 gene was amplified from the genomic DNA by polymerase chain reaction in vitro. And the cloning vector pGEMT-ESAT-6 and shuttle vector ps3000-ESAT-6 which was transformed into M.smegmatis mc2 155 by electroporation. The recombinant M.smegmatis mc2 155 was induced by heating, and then the expression and activity of the target protein were determin...