Schematic diagram of the plasmids engineered for this work.

(A) Plasmid pCHRGFP1: pPROBE-NT containing the chr promoter and chrB gene upstream of gfp. (B) Plasmid pCHRGFP2: pCHRGFP1 with an additional gentamicin resistance gene cloned into mob gene. Arrows indicate the direction of transcription. The restriction enzymes indicated were those used in this work.