DETERMINATION OF CELL FATE IN BACILLUS-SUBTILIS

On starvation, the soil bacterium Bacillus subtilis stops dividing and initiates sporulation, a simple developmental process involving the d ifferentiation of two cell types. Sporulation begins with a reorganiza tion of the cell cycle, to produce cells with the size and chromosome content appropriate for the developmental process. The central divisio n that would normally occur, to produce a pair of identical daughter c ells, is blocked and the cell divides asymmetrically to produce a smal l, polar prespore cell and a much larger mother cell. The developmenta l fates of the two cells are dictated by the locaEized activation of c ell-specific transcription factors, which are controlled by mechanisms that respond to the cellular asymmetry.