ANALYSIS OF THE DUAL REGULATORY MECHANISMS CONTROLLING EXPRESSION OF THE VEGETATIVE CATALASE GENE OF BACILLUS-SUBTILIS

The expression of a vegetative catalase gene, katA (formerly the kat-1 9 gene), is necessary to protect Bacillus subtilis from H2O2, presumab ly by removing the oxidant from the environment. Genetic analysis of k atA revealed that this gene is under two distinct forms of regulation, temporal and H2O2 inducible. The results reported here demonstrate th at (i) the H2O2-inducible regulation of katA gene is not a component o f the SOS regulon, (ii) the regulatory genes spo0A and abrB are involv ed in the temporal regulation but not the H2O2-specific induction of k atA gene expression, and (iii) transcription initiation for the katA g ene occurs at the same site under both forms of regulation.