Activity of the hybrid trp-lac (tac) promoter of Escherichia coli in Pseudomonas putida. Construction of broad-host-range, controlled-expression vectors

Abstract A broad-host-range vector, pKT240, containing the structural gene ( aph ) for aminoglycoside phosphotransferase (APH), without promoter, has been constructed. Insertion of DNA fragments carrying promoters upstreamof the aph gene into the unique Eco RI site of this vector results in the expression of the aph gene and consequently the resistance of the host cells to streptomycin. The new vector has been used to show that the hybrid trp-lac ( tac ) promoter and the promoter of the lacI Q gene of Escherichia coli are active in Pseudomonas putida . Derivatives of pKT240 containing tac and lacI Q sequences may be used as wide-host-range expression vectors. Regulated overproduction of APH and catechol 2,3-oxygenase can be obtained with the aid of the new vectors in both E. coli and P. putida .