Dynamic control of the plasmid copy number maintained without antibiotics in Escherichia coli

BACKGROUND: Manipulating the gene expression is the key strategy to optimize the metabolic flux. Not only transcription, translation, and post-translation level control, but also the dynamic plasmid copy number (PCN) control has been studied. The dynamic PCN control systems that have been developed to date are based on the understanding of origin replication mechanisms, which limits their application to specific origins of replication and requires the use of antibiotics for plasmid maintenance. In this study, we developed a dynamic PCN control system for Escherichia coli that is maintained without antibiotics. This is achieved by regulating the transcription level of the translation initiation factor IF-1 (infA), an essential gene encoded on the plasmid, while deleting it from the plasmid-bearing host cell. RESULTS: When validated using GFP as a reporter protein, our system demonstrated …