Characterization of DegU-dependent expression of bpr in Bacillus subtilis

The response regulator DegU and its cognate histidine kinase DegS constitute a two-component system in the Gram-positive soil bacterium Bacillus subtilis. The phosphorylated form of DegU is known to activate transcription of more than 120 genes in B. subtilis, including the bpr gene encoding bacillopeptidase F. To characterize DegU-dependent regulation of bpr, the interaction of the bpr regulatory region with His-tagged DegU was analyzed using gel retardation and footprint analyses. This revealed that DegU bound three direct repeats of a motif that is known to be arranged as an inverted repeat in the comK promoter, to which DegU binds. Mutational analysis using a bpr-lacZ fusion revealed that the three direct repeats in bpr are needed for DegU-dependent transcription activation.