Effects of Bacillus subtilis sporulation regulatory protein SpoIIID on transcription by sigma K RNA polymerase in vivo and in vitro.

SpoIIID is a sequence-specific, DNA-binding protein that activates or represses transcription of different genes by sigma K RNA polymerase in vitro. A Bacillus subtilis strain engineered to produce both sigma K and SpoIIID during growth showed effects of SpoIIID on expression of sigma K-dependent genes that were consistent with the effects of a small amount of SpoIIID on transcription of these genes in vitro, indicating that the strain provides a simple, in vivo method to screen for effects of SpoIIID on transcription of sigma K-dependent genes.