FIG. 2.

Strains containing GATC mutations in the dnaA promoter. The first nucleotide of each GATC site and in the DnaA box (represented at the extreme left) are indicated with respect to the relative position to each other and to the 100-bp fragment representing the dnaAp₂ promoter (drawn to scale). The GATC sites present in the dnaA promoter sequence are numbered. The dnaAp₂ transcriptional start site is present between GATC sites 2 (−10) and 3. The plasmids and the strains ultimately constructed are to the left and extreme right, respectively. Black diamonds indicate the first G in a GATC site that was eliminated by site-specific mutagenesis.