Mutational analysis of the phoD promoter in Bacillus subtilis: implications for PhoP binding and promoter activation of Pho regulon promoters

Oligo-directed mutagenesis, DNase I footprinting and in vivo transcription assays have been used in studying the regulatory region of the phoD promoter in Bacillus subtilis. Results indicate that a dimer of Pho-P can stably bind two consensus repeats while PhoP binding is highly cooperative within the core promoter region. It has also been found out that specific bases made up of TT(A/T/C)ACA consensus are necessary for transcriptional activation. The spacing between two consensus repeats within a putative dimer binding site in the core region is important for PhoP binding and promoter activation.