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

Abstract

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 β-galactosidase was efficiently repressed at 37°C but rapidly induced upon transfer to the 15-to-30°C range, leading to a three- to fivefold increase in specific activity relative to control cultures. Although the initial rates of β-galactosidase accumulation at 20°C were twice those measured at 15°C, prolonged incubation at 20°C, but not 15°C, led to a dilution of activity due to repression of the promoter and cell division.