Chicken ovalbumin is synthesized and secreted by Escherichia coli

By recombinant DNA methods, the chicken ovalbumin structural gene has been fused to Escherichia coli lac transcriptional and translational control regions. When a plasmid containing the hybrid gene was introduced into E. coli, a protein identified as ovalbumin by immunoreactivity and sodium dodecyl sulfate/polyacrylamide gel electrophoresis was synthesized. The chicken ovalbumin made in bacteria was full length (43,000 daltons) and constituted 1.5% of the cellular protein. In addition, the microbially synthesized ovalbumin was secreted through the cell membrane into the periplasmic space of E. coli. The ability of the E. coli secretory apparatus to recognize chicken ovalbumin, which is normally synthesized and secreted in hen oviducts, suggests that common features exist in the secretion-recognition mechanisms found in these two organisms. The bacterial synthesis of significant amounts of chicken ovalbumin demonstrates that the E. coli cellular machinery may be utilized to synthesize a higher eukaryotic protein which is relatively stable in the bacterial intracellular environment.