Mutations in the Precursor Region of a Bacillus subtilis Sporulation Sigma Factor

Transcription frm some sporulation-specific promoters ofBacilus subdiis is dependent on synthesis of procoE and its conversion to cE by proteolysis. Certain mutations in the precursor region of sigE, the gene encoding pro-r9, apparently allow the mutant sigE products to be active as v factors without being proteobsed in the normal way. Temporal regulation of gene expression during sporulation in Bacillus spp. is controlled at least in part by sequential replacement of the or factor component of RNA polymerase (17, 28). At least 10 forms of Bacillus subtilis RNA polymer-ase that differ only in their cr factors are present in vegetative or sporulating cells or both (3, 18). Each enzyme recognizes a set of promoter sites with a characteristic consensus sequence. These various sets of promoters direct transcrip-tion of groups of genes at characteristic times and in char-acteristic subcellular compartments during growth or during sporulation or both (16, 18)