Cloning and characterization of DNA damage-inducible promoter regions from Bacillus subtilis

DNA damage-inducible (din) genes in Bacillus subtilis are coordinately regulated and together compose a global regulatory network that has been termed the SOS-like or SOB regulon. To elucidate the mechanisms of SOB regulation, operator/promoter regions from three din loci (dinA, dinB, and dinC) of B. subtilis were cloned. Operon fusions constructed with these cloned din promoter regions rendered reporter genes damage inducible in B. subtilis. Induction of all three din promoters was dependent upon a functional RecA protein. Analysis of these fusions has localized sequences required for damage-inducible expression of the dinA, dinB, and dinC promoters to within 120-, 462-, and 139-bp regions, respectively. Comparison of the nucleotide sequences of these three din promoters with the recA promoter, as well as with the promoters of other loci associated with DNA repair in B. subtilis, has identified the consensus sequence GAAC-N4-GTTC as a putative SOB operator site.