Expression of the σF-Directed csfB Locus Prevents Premature Appearance of σG Activity during Sporulation of Bacillus subtilis

During sporulation, σG becomes active in the prespore upon the completion of engulfment. We show that the inactivation of the σF-directed csfB locus resulted in premature activation of σG. CsfB exerted control distinct from but overlapping with that exerted by LonA to prevent inappropriate σG activation. The artificial induction of csfB severely compromised spore formation.