Identification and characterization of the immunity repressor (ImmR) that controls the mobile genetic element ICEBs1 of Bacillus subtilis

Mol Microbiol. 2007 Jun;64(6):1515-28. doi: 10.1111/j.1365-2958.2007.05748.x. Epub 2007 May 18.


ICEBs1 is a mobile genetic element found in the chromosome of Bacillus subtilis. Excision and transfer of ICEBs1 is regulated by the global DNA damage response and intercellular peptide signalling. We identified and characterized a repressor, ImmR (formerly YdcN), encoded by ICEBs1. ImmR represses transcription of genes required for excision and transfer, and both activates and represses its own transcription. ImmR regulates transcription within ICEBs1 by binding to several sites in the region of DNA that contains promoters for both immR and xis (encoding excisionase). In addition, we found that ImmR confers immunity from acquisition of additional copies of ICEBs1. ImmR-mediated regulation serves to keep a single copy of ICEBs1 stably maintained in the absence of induction, allows a rapid response to inducing signals, and helps limit acquisition of additional copies of ICEBs1.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacillus subtilis / genetics*
  • Bacillus subtilis / growth & development
  • Bacillus subtilis / metabolism
  • Bacterial Proteins* / chemistry
  • Bacterial Proteins* / genetics
  • Bacterial Proteins* / metabolism
  • Base Sequence
  • Conjugation, Genetic
  • DNA Nucleotidyltransferases / chemistry
  • DNA Nucleotidyltransferases / genetics
  • DNA Nucleotidyltransferases / metabolism
  • DNA, Intergenic / chemistry
  • Gene Expression Regulation, Bacterial*
  • Interspersed Repetitive Sequences / genetics*
  • Molecular Sequence Data
  • Repressor Proteins* / chemistry
  • Repressor Proteins* / genetics
  • Repressor Proteins* / metabolism
  • Viral Proteins / chemistry
  • Viral Proteins / genetics
  • Viral Proteins / metabolism


  • Bacterial Proteins
  • DNA, Intergenic
  • Repressor Proteins
  • Viral Proteins
  • DNA Nucleotidyltransferases
  • excisionase