After the identification of the transcriptional start site of vqsR, a putative las box was identified by visual inspection. vqsRp-lacZ fusion experiments showed that vqsR promoter is more sensitive to activation by the las system than the rhl system. EMSAs confirmed direct interaction between the vqsR promoter and the las system. To examine whether the apparent las box motif in the vqsR promoter is critical for QS regulation, a series of vqsRp-lacZ fusions containing point mutations in the apparent las box were constructed. EMSAs in conjuction with the site-directed mutagenesis showed that the las box of vqsR is important for binding of LasR to the vqsR promoter and that conserved positions 3 and 18 in the las box are the most crucial for binding of LasR to the vqsR promoter.
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|