Curation Information

fleQ, the gene encoding the major flagellar regulator of Pseudomonas aeruginosa, is sigma70 dependent and is downregulated by Vfr, a homolog of Escherichia coli cyclic AMP receptor protein.;Dasgupta N, Ferrell EP, Kanack KJ, West SE, Ramphal R;Journal of bacteriology 2002 Oct; 184(19):5240-50 [12218009]
Vfr [P55222, view regulon]
Reported TF sp.
Pseudomonas aeruginosa PAO1
Reported site sp.
Pseudomonas aeruginosa PAO1
Created by
Dinara Sagitova
Curation notes

Experimental Process

The authenticity of the putative Vfr binding site was verified by EMSAs and DNase I footprinting. The protected sequence contained the predicted Vfr binding site. A semiquantitative Western analysis showed a lower FleQ production. To further confirm the repression of fleQ by Vfr, fleQ-lacZ fusions were constructed. The results of these fusions showed a two-fold change in fleQ expression in P. aeruginosa PAO1. Site-directed mutagenesis introducing an ACA-to-CGC mutation in the fleQ promoter showed that the activity of the mutated promoter was not repressed by overproduction of Vfr in PAO1, indicating that Vfr was not able to bind to the fleQ promoter in vivo in strain PAO1.

Transcription Factor Binding Sites


Gene Regulation

Regulated genes for each binding site are displayed below. Gene regulation diagrams show binding sites, positively-regulated genes, negatively-regulated genes, both positively and negatively regulated genes, genes with unspecified type of regulation. For each indvidual site, experimental techniques used to determine the site are also given.

Site sequence Regulated genes Gene diagram Experimental techniques TF function TF type
... ... fleQ fleS fleR
Experimental technique details Beta-gal reporter assay - Experimental technique details DNAse footprinting (ECO:0005631) - Experimental technique details EMSA (ECO:0001807) - Experimental technique details PSSM site search (ECO:0005659) - Experimental technique details Site directed mutagenesis (ECO:0005667) - repressor not specified