The Bacillus subtilis regulator SinR inhibits spoIIG promoter transcription in vitro without displacing RNA polymerase

Nucleic Acids Res. 1998 Aug 15;26(16):3806-12. doi: 10.1093/nar/26.16.3806.


Initiation of sporulation in Bacillus subtilis is controlled by several regulators which affect activation by phosphorylation of the key response regulator Spo0A or transcription of Spo0A-P-dependent genes. In vivo overexpression of one of these regulators, sinR , results in suppression of transcription from the Spo0A-P-dependent promoters of spo0A , spoIIA , spoIIE and spoIIG and in vitro SinR binds to the promoters of the spoIIA operon and the spo0A gene. In this study we have demonstrated that in vitro SinR directly repressed Spo0A- P-dependent transcription by B.subtilis RNA polymerase from the spoIIG operon promoter. SinR inhibited transcription prior to formation of heparin-resistant complexes but did not displace RNA polymerase from the spoIIG promoter. DNase I protection studies demonstrated that SinR protected a large region of the spoIIG promoter and induced DNase I hypersensitive sites, particularly around the 0A boxes, at the same positions as those induced by zinc. Since binding of zinc induces bends in the DNA, we concluded that SinR binding also altered the conformation of the spoIIG promoter. We propose that SinR-induced conformational changes in Spo0A-dependent promoters prevent activation of trans-cription by Spo0A-P.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / genetics*
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism
  • DNA-Directed RNA Polymerases / metabolism
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Promoter Regions, Genetic*
  • Sigma Factor / genetics*
  • Transcription Factors / genetics*
  • Transcription, Genetic


  • Bacterial Proteins
  • DNA, Bacterial
  • Sigma Factor
  • Transcription Factors
  • sporulation-specific sigma factors
  • FlaD protein, Bacteria
  • DNA-Directed RNA Polymerases