Interactions among mutations that cause altered timing of gene expression during sporulation in Bacillus subtilis

Abstract

The ski4::Tn917lac insertion mutation in Bacillus subtilis was isolated in a screen for mutations that cause a defect in sporulation but that are suppressed by the presence or overexpression of the histidine protein kinase encoded by kinA (spoIIJ). ski4::Tn917lac caused a small defect in sporulation, but in combination with a null mutation in kinA, it caused a much more severe defect. The insertion mutation was in an 87-amino-acid open reading frame (orf87 bofA) that controls the activation of a sigma factor, sigma K, at intermediate times during sporulation. The ski4 mutation caused the premature expression of cotA, a gene controlled by sigma K. An independent mutation that causes the premature activation of sigma K also caused a synthetic (synergistic) sporulation phenotype in combination with a null mutation in kinA, indicating that the defect was due to altered timing of gene expression directed by sigma K. Expression of ski4 was shown to be controlled by the sporulation-specific sigma factor sigma E.

Characterization of csh203::Tn917lac, a mutation in Bacillus subtilis that makes the sporulation sigma factor sigma-H essential for normal vegetative growth

“…DNA adjacent to the csh203::Tn917lac transposon was sequenced from pKH37 by using the Sequenase kit (U.S. Biochemical Corp.) and primers KI-1 (5Ј-GTGGGAATTTGTACCCC-3Ј) and KI-3 (5Ј-AGAGAGAT GTCACCGTC-3Ј), which are specific to the ends of the transposon (15). Media and growth conditions.…”

Characterization of bofA, a gene involved in intercompartmental regulation of pro-sigma K processing during sporulation in Bacillus subtilis

“…The sporulation gene spoIIJ (kinA) encodes a histidine protein kinase that activates the early-acting sporulation regulatory protein SpoOA via a phosphate relay (2,3). Mutations in spoIIJ impair sporulation only weakly but cause a more severe block in sporulation when combined with ski mutations, which by themselves have little effect on sporulation (14). Thus, spoIIJ and ski mutations act synergistically to cause a strong block in sporulation.…”

“…4B. Because transcription of bofA is under the control of &- (14) and because at least some cr'-directed gene expression is confined to the mother cell (9), we assume in our model that…”

“…This 75-bp region (Fig. 2) contains at a spacing of 14 bp the sequences CATAag-T and GtcTAaa, which conform well (matching in five out of seven positions) and moderately well (matching in three out of seven positions), respectively, to the consensus -10 (CATACA-T) and -35 (kmATATT, where k is a T or a Gand m is a C or an A) sequences for oF-recognized promoters (24). Experiments by Ireton and Grossman (14) (1).…”

“…Remarkably, bofA (orf87) is the site of a recently isolated mutation called ski4, which was isolated by a strategy unrelated (or seemingly unrelated) to the bypass of forespore phenotype (14). The sporulation gene spoIIJ (kinA) encodes a histidine protein kinase that activates the early-acting sporulation regulatory protein SpoOA via a phosphate relay (2,3).…”