EMSA with promoter fragments of different length identified the AbrB2 binding region. abrB2-cat reporter assays demonstrated that AbrB2 is an autorepressor. 5'RACE analysis was used to map the transcription start site of abrB2. RT-PCR showed that hoxEFUYH operon was at least 2.5-fold more abundant in the abrB2-deleted mutant than in the WT strain. EMSA with a series of 5' deletions of the hox operon promoter identified the AbrB2 binding region. A possible consensus sequence (TT(N5)AAC) was determined by searching for a motif that occurs in the abrB2 and the hox promoter subfragments. Site-directed mutagenesis verified that the promoter activity increased when TT -> GG substitutions were made.
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|