The Bacillus subtilis SinR protein is a repressor of the key sporulation gene spo0A.
SinR is a pleiotropic DNA binding protein that is essential for the late-growth processes of competence and motility in Bacillus subtilis and is also a repressor of others, e.g., sporulation and subtilisin synthesis. In this report, we show that SinR, in addition to being an inhibitor of sporulation stage II gene expression, is a repressor of the key early sporulation gene spo0A. The sporulation-specific rise in spo0A expression at time zero is absent in a SinR-overproducing strain and is much higher than normal in strains with a disrupted sinR gene. This effect is direct, since SinR binds specifically to spo0A in vitro, in a region overlapping the -10 region of the sporulation-specific Ps promoter that is recognized by E-sigma H polymerase. Methyl interference and site-directed mutagenesis studies have identified guanine residues that are important for SinR recognition of this DNA sequence. Finally, we present evidence that SinR controls sporulation through several independent genes, i.e., sp0A, spoIIA, and possibly spoIIG and spoIIE.
Mandic-Mulec
I
I
Public Health Research Institute, New York, New York 10016, USA.
Doukhan
L
L
Smith
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I
D001412:Bacillus subtilis / Q000235:genetics* / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013171:Spores, Bacterial; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C076733:FlaD protein, Bacteria