The Bacillus subtilis spo0J gene: Evidence for involvement in catabolite repression of sporulation

Previous observations concerning the ability of the Bacillus subtilis bacteriophages SP10 and PMB12 to suppress mutations in spo0J and to make wild-type sporulation catabolite resistant suggested that spo0J had a role in catabolite repression of sporulation. This suggestion was supported in the present report by the ability of the catabolite-resistant sporulation mutation crsF4 to suppress a Tn917 insertion mutation of the B. subtilis spo0J locus (spo0J::Tn917ΩHU261) in medium without glucose. Although crsF4 and SP10 made wild-type B. subtilis sporulation catabolite resistant, neither crsP4 nor SP10 caused a mutant with spo0J::Tn917ΩHU261 to sporulate in medium with glucose. Sequencing the spo0J locus revealed an open reading frame that was 179 codons in length. Disruption of the open reading frame resulted in a sporulation-negative (Spo^-) phenotype that was similar to those of other spo0J mutations. Analysis of the deduced amino acid sequence of the spo0J locus indicated that the spo0J gene product contains an α-helix-turn-α-helix unit similar to the motif found in λ Cro-like DNA-binding proteins.