EXPRESSION OF A STRESS-INDUCED AND STARVATION-INDUCED DPS PEXB-HOMOLOGOUS GENE IS CONTROLLED BY THE ALTERNATIVE SIGMA-FACTOR SIGMA(B) IN BACILLUS-SUBTILIS/

sigma(6)-dependent general stress proteins (G:sps) of Bacillus subtili s are essential for the development of glucose-stravation-induced cros s-resistance to oxidative challenge. However, the proteins directly in volved in this nonspecific resistance to oxidative stress have to be i dentified. We found that one prominent Gsp displayed strong sequence s imilarity to the previously characterised oxidative-stress-inducible M rgA protein of B. subtilis and to the starvation-induced Dps/PexB prot ein of Escherichia coli. We therefore designated this prominent Gsp Dp s. While MrgA belongs to the peroxide-stress-inducible proteins needed for the H2O2-inducible adaptive response to oxidative stress, Dps bel ongs to the proteins induced by heat, salt, or ethanol stress and afte r starvation for glucose but not by a sublethal oxidative challenge. P rimer extension experiments identified two overlapping promoters upstr eam of the coding region of dps, one being sigma(B) dependent (P-B) an d the other being sigma(B) independent (P-1). Both promoters contribut e to the basal level of dps during growth. After stress or during entr y into the stationary phase, transcription from P-B strongly increased whereas transcription from P-1 decreased. Mutant strains lacking Dps completely failed to develop glucose-starvation-induced resistance to oxidative stress. These results confirm our suggestion that sigma(B)-d ependent general stress proteins of B. subtilis are absolutely require d for the development of nonspecific resistance to oxidative stress.