ABSTRACT
The presence of excess glucose in growth media prevents normal sporulation of Bacillus subtilis. The crsA47 mutation, located in the gene for the vegetative phase sigma factor (sigma(A)) results in a glucose-resistant sporulation phenotype. As part of a study of the mechanisms whereby the mutation in sigma(A) overcomes glucose repression of sporulation, we examined the expression of genes involved in sporulation initiation in the crsA47 background. The crsA47 mutation had a significant impact on a variety of genes. Changes to stage II gene expression could be linked to alterations in the expression of the sinI and sinR genes. In addition, there was a dramatic increase in the expression of genes dependent on the minor sigma factor sigma(H). This latter change was paralleled by the pattern of spo0H gene transcription in cells with the crsA47 mutation. In vitro analysis of RNA polymerase containing sigma(A47) indicated that it did not have unusually high affinity for the spo0H gene promoter. The in vivo pattern of spo0H expression is not predicted by the known regulatory constraints on spo0H and suggests novel regulation mechanisms that are revealed in the crsA47 background.
Subject(s)
Bacillus subtilis/genetics , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Glucose/metabolism , Mutation , Sigma Factor/genetics , Transcription Factors/genetics , Bacillus subtilis/growth & development , Bacillus subtilis/physiology , DNA-Binding Proteins/genetics , DNA-Directed RNA Polymerases/genetics , Gene Expression Regulation, Developmental , Genotype , Kinetics , Spores, Bacterial/physiology , Time Factors , Transcription, GeneticABSTRACT
The carboxy-terminal domain of Spo0A in Bacillus subtilis is one of the few response regulator activation domains for which the structure is known. Here, we discuss some of the mutational data and biological roles of Spo0A in light of its structure.