The comparison of 3OC12-HSL production in P. aeruginosa PAO1 and its rsaL derivative mutant by thin-layer chromatography revealed that 3OC12-HSL production is dramatically enhanced in the rsaL mutant. Wild-type expression levels were restored by complementation of the rsaL mutant with the plasmid pPSRsaLPAO. Repression of lasI gene by RsaL was confirmed by lacZ reporter assays. EMSA showed that RsaL is able to specifically bind the lasI promoter. DNase I footprinting assays showed that RsaL binding spans at least from nucleotides −22 to −9 with respect to the lasI transcription starting point and is located approximately at the center of a palindromic region consisting of two 5′-AAnTTATGnAA-3′ inverted sequences interrupted by a single nucleotide and partially overlaps the −10 consensus for σ70 recognition.
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|