To Sporulate or Not to Sporulate: Developmental Checkpoints Monitoring Bacillus subtilis Sporulation

Developmental processes are carefully regulated programs that are present in multiple kingdoms of life and that generally result in cell differentiation and specialization. This regulation can be mediated in part by checkpoints that monitor the progression of development to ensure that earlier steps occur successfully before later steps are initiated. Bacterial endospore formation (i.e., sporulation) is a well-studied developmental program that transforms a progenitor cell into a dormant cell type in response to environmental stress and that serves as a model for the discussion of checkpoint mechanisms used to monitor development. This review focuses on the checkpoints monitoring bacterial sporulation, with an emphasis on the model gram-positive bacterium Bacillus subtilis, to highlight general strategies that may be broadly conserved among disparate developmental programs.