comK Encodes the Competence Transcription Factor, the Key Regulatory Protein for Competence Development in Bacillus Subtilis

Mol Microbiol. 1995 Feb;15(3):455-62. doi: 10.1111/j.1365-2958.1995.tb02259.x.


comK is a positive autoregulatory gene occupying a central position in the competence-signal-transduction network. All regulatory routes identified in this network converge at the level of comK expression. The ComK protein is required for the transcriptional induction of comK and the late competence genes, which specify morphogenetic and structural proteins necessary for construction of the DNA-binding and uptake apparatus. In this report we demonstrate that ComK specifically binds to DNA fragments containing promoter and upstream sequences of the genes it affects (comC, comE, comF, comG and comK). Using portions of the region upstream of comC we show that the ComK-binding sequences are essential for the expression of competence. Moreover, we demonstrate that the presence of ComK stimulates the expression of comF-lacZ and comG-lacZ translational fusions in vivo in Escherichia coli. These results indicate that the gene product of comK is identical to the previously inferred competence transcription factor (CTF).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacillus subtilis / genetics*
  • Bacillus subtilis / growth & development
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / physiology
  • Base Sequence
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Morphogenesis
  • Operon
  • Promoter Regions, Genetic
  • Regulatory Sequences, Nucleic Acid
  • Sequence Alignment
  • Transcription Factors / genetics*
  • Transcription Factors / physiology
  • Transcription, Genetic
  • Transformation, Genetic* / genetics


  • Bacterial Proteins
  • DNA, Bacterial
  • Transcription Factors
  • comK protein, Bacillus subtilis