The outB gene of Bacillus subtilis regulates its own transcription

The outB gene of Bacillus subtilis is under the control of two promoters (P1 and P2). To study the regulation of expression from the P1 promoter we have constructed a set of multicopy plasmids carrying different portions of the outB region and analyzed the transcripts present in vivo by RNase protection experiments. The data indicate that the product of gene outB regulates its own transcription from the P1 promoter. We also constructed an outB-lacZ fusion in an insertional plasmid. The plasmid was inserted into the chromosome adjacent to or distal from the outB gene. Assays of beta-galactosidase activity and RNase protection experiments are in accordance with a model implying that the product of gene outB regulates the initiation of transcription from the P1 promoter acting in the cis configuration.