Fig. 2.

Binding of MrpC2 and FruA to the fmgE promoter region. (A) Effects of mutations in the fmgE promoter region on fmgE-lacZ expression in vivo and on MrpC2 and FruA binding in vitro. (Top) Summary of the effects of four mutations on developmental fmgE-lacZ expression (55). The mutations are shown, and the numbers indicate the maximum β-galactosidase activity during development, expressed as a percentage of the maximum activity observed for the wild-type promoter. (Bottom) EMSAs with ³²P-labeled fmgE DNA (2 nM) spanning from positions −100 to −25 and His₁₀-MrpC2 (1 μM), FruA-His₆ (3 μM), or both His₁₀-MrpC2 (1 μM) and FruA-His₆ (3 μM), as indicated. The probe DNA had the wild-type (WT) sequence or the indicated mutation. The filled arrowhead points to the shifted complex produced by His₁₀-MrpC2 alone, and the open arrowhead points to the complex produced by FruA-His₆ alone. (B) Summary of binding sites for MrpC2 and FruA in the fmgE promoter region. The approximate location and relative positions of MrpC2 and FruA at sites 1, 2, and 3 are deduced from the effects of 5′-end deletions, the mutations shown in panel A, and 3′-end deletions, respectively, on binding in vitro, as explained in the text. The position of MrpC2 binding alone, depicted upstream of position +50, is less precisely known but lies between positions −25 and +50.