FIG 6.

CsgD and CpxR regulate different components in the network controlling FliA expression. (A) Seven major regulators of E. coli are known to modulate flagellar biosynthesis, mostly by controlling FlhDC (see introduction). (B) Measurements of GFP transcriptional fusions in the wild-type strain and its rpoS, csgD, and cpxR mutants in M9 medium at 37°C. Gene expression values were calculated, in stationary phase (absorbance at 600 nm of 0.6), as the ratio of the relative fluorescence of the mutant versus the WT strains in at least 3 independent experiments. Very similar gene expression ratios were found in exponential phase (absorbance of 0.2). (C) Proposed model controlling cell adhesion and motility. Black arrows indicate known regulation, while green and red arrows show new stimulatory or repressive interactions, respectively, between key regulators.