DNA-related conditions controlling the initiation of sporulation in Bacillus subtilis.

In the Gram-positive bacterium Bacillus subtilis, the developmental process of spore formation occurs in response to nutrient deprivation and requires the generation of two different cell types with distinct programs of gene expression. Entry into sporulation is regulated primarily by activation (phosphorylation) of the transcription factor encoded by spo0A. The phosphorylation state of Spo0A is controlled by a multi-component phospho-transfer pathway and by at least one phosphatase. Recent experiments indicate that several intracellular conditions that decrease the fidelity of chromosome transmission inhibit production of Spo0A approximately P. These conditions include inhibition of DNA replication, DNA damage, and some alterations in the chromosome partitioning and cell division machinery. Coupling accumulation of a critical level of Spo0A approximately P to these conditions seems to serve as a developmental checkpoint to ensure that cells do not attempt to sporulate unless they are able to provide an intact, undamaged chromosome for each of the two cell types needed for sporulation.