THE CHLOROPLAST PSBA PROMOTER IS MORE EFFICIENT IN ESCHERICHIA-COLI THAN THE T7 PROMOTER FOR HYPEREXPRESSION OF A FOREIGN PROTEIN

The T7 promoter is commonly used in E. coli expression studies but has several disadvantages due to induction with isopropylthio-beta-D-gala ctoside (IPTG) including the prohibitive cost of IPTG, reduction in ce ll growth, and the poisonous nature of IPTG prohibiting its use in pha rmaceutical products. The chloroplast psbA promoter produces an 18.5 f old increase in expression in E. coli compared to the T7 promoter. Als o, the psbA promoter does not have the disadvantages of induction with IPTG.