BIOCHEMICAL AND GENETIC-CHARACTERIZATION OF A COMPETENCE PHEROMONE FROM BACILLUS-SUBTILIS

We have purified and characterized a modified peptide pheromone that a ccumulates in culture medium as B. subtilis grows to high density. Thi s pheromone is required for the development of genetic competence. Whe n added to cells at low density, the pheromone induces the premature d evelopment of competence. The peptide moiety of the pheromone matches nine of the last ten amino acids predicted from a 55 codon open readin g frame, comX. comX and comQ, the gene immediately upstream of comX, a re required for production of the pheromone. Response to the pheromone requires the comP-comA two-component regulatory system and the oligop eptide permease encoded by spoOK. SpoOK could transport the pheromone into the cell, or function as a receptor, binding the pheromone and se nding a transmembrane signal, leading to activation of the ComA transc ription factor and induction of competence development.