FIG. 1.
ABC model system. This model consists of the Pm promoter, which drives transcription of the meta-cleavage pathway of the TOL plasmid, and the xylS gene, which encodes the sensor protein (○) that interacts with alkylbenzoates and stimulates transcription from Pm (•). In the containment system the lacI gene coding for the LacI repressor protein (□) was cloned downstream from Pm. The lethal element consists of the Plac promoter fused to the gef gene of E. coli, a member of the hok gene family (15), which encodes a pore-forming protein. The system performs as described in the text. 3MB, 3-methylbenzoate.