Binding of Spo0A stimulates spoIIG promoter activity in Bacillus subtilis

Abstract

The spoIIG promoter is used by RNA polymerase containing cA (E&r), the primary form of RNA polymerase found in vegetative cells in BaciUus subtilis. However, the spolIG promoter is active only after the onset of sporulation. Activation of the spoIIG promoter requires the product of the spoOA gene (SpoOA). SpoOA is a sequence-specific DNA-binding protein which binds to two sites in the spoIIG promoter that are essential for promoter activity. We found that single-base-pair substitutions in these two regions that reduced promoter activity in vivo caused reduced binding of SpoOA in vitro, and one substitution that increased promoter activity in vivo increased the affinity of SpoOA for this DNA in vitro. Furthermore, SpoOA stimulated transcription from the spolIG promoter by Ecr in vitro. These results support the model that binding of SpoOA activates EMA-dependent transcription from the spoIIG promoter after the onset of sporulation.Under conditions of nutrient deprivation the bacterium Bacillus subtilis undergoes complex morphological and physiological changes that result in the formation of an endospore (reviewed in reference 16). Endospore formation requires the expression of over 50 genetic loci, and these loci are transcribed in a precise temporal sequence. At least six of these genetic loci encode secondary sigma factors which confer on RNA polymerase the ability to transcribe different subsets of genes (reviewed in reference 10). The production of these sporulation-specific sigma factors plays a fundamental role in regulating the gene expression required for sporulation. However, RNA polymerase containing 0A (EoA), the primary sigma factor in vegetative cells, also plays a role in the expression of genes during sporulation by directing the transcription of at least two key operons during the early stages of sporulation (5, 9, 23). One of the promoters used by EoA after the onset of sporulation directs the expression of the spoIIG operon which encodes the structural gene for cE (8), a secondary sigma factor necessary for the transcription of later sporulation genes.

The master regulator for entry into sporulation inBacillus subtilisbecomes a cell-specific transcription factor after asymmetric division

“…It is derived by proteolytic processing from an inactive proprotein precursor, pro-E (Stragier and Losick 1996;Piggot and Losick 2002). Both pro-E and its processing enzyme, SpoIIGA, are encoded by the spoIIG operon (Jonas et al 1988), which is under the direct control of Spo0A (Satola et al 1992). As shown previously (Fujita and Losick 2002) and confirmed here, transcription of spoIIG largely takes place after the formation of the polar septum when it is confined to the mother cell.…”

KapB is a lipoprotein required for KinB signal transduction and activation of the phosphorelay to sporulation in Bacillus subtilis

“…The promoter region of spoIIG was recovered from a Hin dIIIEcoRI digestion of plasmid pUCIItrpA (Satola et al, 1992) and subcloned in pJM115 (Perego, 1993) to give pJT103. Plasmid pJV198 contains the kapB ORF from the upstream ClaI site until the stop codon subcloned at the SphI site of the B. subtilis expression vector pMA5 (Dartois et al, 1994) after Klenow polymerase fill-in of both insert and vector.…”

Integration of multiple developmental signals in Bacillus subtilis through the Spo0A transcription factor.

“…One of the key regulatory factors required for the initiation of sporulation is the spoOA gene product, spoOA encodes a transcription factor that can activate or repress transcription depending on the DNA target (Strauch et al 1990;Satola et al 1991Satola et al , 1992York et al 1992). Spo0A belongs to a large family of bacterial regulatory proteins called response regulators that have conserved amino termini (Ferrari et al 1985;Kudoh et al 1985).…”