Recombinant protein expression at low temperatures under the transcriptional control of the major Escherichia coli cold shock promoter cspA.

A transcriptional gene fusion between the cspA promoter and the lacZ gene was constructed to assess the usefulness of cold shock promoters for low-temperature protein expression. Synthesis of beta-galactosidase was efficiently repressed at 37 degrees C but rapidly induced upon transfer to the 15-to-30 degrees C range, leading to a three- to fivefold increase in specific activity relative to control cultures. Although the initial rates of beta-galactosidase accumulation at 20 degrees C were twice those measured at 15 degrees C, prolonged incubation at 20 degrees C, but not 15 degrees C, led to a dilution of activity due to repression of the promoter and cell division.