SIGMA(B)-DEPENDENT REGULATION OF GSIB IN RESPONSE TO MULTIPLE STIMULIIN BACILLUS-SUBTILIS

The expression of the gsiB gene of Bacillus subtilis in response to a wide variety of stress conditions was analysed, and the results provid e evidence that gsiB is subject to a sigma(B)-dependent regulation. Pr imer extension experiments established identical start points for gsiB transcription during growth and after the induction by heat shock, sa lt or ethanol stress, and glucose limitation. The sequence upstream of the transcription start point shows great similarity to the sequences of sigma(B)-dependent promoters of B. subtilis. sigma(B) was absolute ly required for the increase in gsiB mRNA level and in the synthesis r ate of GsiB in response to various stimuli. Measurements of the ATP po ol indicated that changes in the level of ATP might be one of the sign als that regulate the activity of sigma(B) in B. subtilis.