FIG. 2.

(A) Comparison of the Ω4499 promoter region to promoters of M. xanthus genes believed to be transcribed by σ⁵⁴ RNA polymerase (see text for references). Also shown is the consensus sequence to which E. coli σ⁵⁴ binds (49). The numbers to the left indicate the location within the promoter relative to the start site of transcription. The bold nucleotides indicate those that match the consensus sequence, and the underlined nucleotides match those most highly conserved in the consensus sequence. (B) Mutational analysis of the −25 to −10 bp region of the Ω4499 promoter. Developmental lacZ expression was determined for M. xanthus strains bearing integrated plasmids with a mutation at −12 to −10 bp from CGA to TAT (⧫) or a mutation at −25 bp from T to G (▴). The Ω4499 wild-type promoter region from −218 to +50 bp (▪) (four determinations in two experiments) and the vector with no promoter insert (•) were included as controls. The meaning of points and error bars is the same as described in the Fig. 1 legend.