FIG. 2.

Genetic maps the carB regions of plasmids and strains used in this work. The physical map and the positions of selected restriction endonuclease sites are shown. The carB DNAs contained in the different plasmids are shown with lines. The dotted line in pKS2 indicates that the cloned lactococcal DNA extends to a Sau3A site at 6.1 kb. A P indicates the position of the carB promoter. The maps of the chromosomal DNA in the carB regions of the wild type (WT), MB35, MB36, MB37, and MB38 are shown. The broken lines represent the E. coli plasmid DNA, which is not drawn to scale. The erythromycin resistance genes of MB36, MB37, and MB38 are not shown. The carB terminator and the carB attenuator are shown by omega- and double-omega-like structures, respectively.