A ptxS-lacZ fusion identified PtxS as an auto-repressor, with ptxS expression levels four- to fivefold higher in the ptxS isogenic mutant. EMSA confirmed that PtxS binds specifically to a 52 bp fragment in the ptxS upstream region. DNase I footprinting further determined the location of a PtxS binding fragment. Site-directed mutagenesis combined with EMSA verified this fragment as a putative binding site.
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|