FIG. 5.

Single-base-pair changes in the C-box-like sequence centered at bp −52 have dramatic effects on Ω4406 expression, and the pattern of effects is different than for C boxes mutated previously. (A) Developmental expression from the wild-type DNA segment spanning from bp −100 to 320 (▴) or the same segment with a T-to-G change at bp −53 (•) or an A-to-C change at bp −54 (⧫), fused to lacZ and integrated at the Mx8 phage attachment site in the chromosome of M. xanthus wild-type DK1622, was measured for three independently isolated transformants (see Materials and Methods). The vector with no insert was included as a control (▵). The meaning of points and error bars is the same as described in the Fig. 1 legend. The error bars are too small to be seen except in the case of the base pair segment from −100 to 320 with the A-to-C change at −54 bp. (B) Comparison of the effects of single-base-pair transversion mutations in the C-box-like sequence centered at bp −52 in the Ω4406 promoter region and in four different C boxes. The x-axis represents the position in the C box (or C-box-like sequence) corresponding to the consensus sequence CAYYCCY with the A being position 2, etc. The bars represent the average maximum developmental lacZ activity expressed as a percentage of the wild-type promoter activity for the C boxes centered at bp −49 in the Ω4400 (47) and Ω4403 (46) promoter regions, at bp −33 in the Ω4499 promoter region (48), at bp −51 in the fruA promoter region (43), or for the C-box-like sequence centered at bp −52 in the Ω4406 promoter region (Table 2). Error bars show one standard deviation of the data.