Regulation of toxin and bacteriocin synthesis in Clostridium species by a new subgroup of RNA polymerase sigma-factors

Res Microbiol. 2006 Apr;157(3):201-5. doi: 10.1016/j.resmic.2005.11.004. Epub 2005 Dec 29.


Many Clostridium species are pathogenic for humans and animals, and most of the resulting diseases, such as tetanus, botulism, gas gangrene and pseudomembranous colitis, are due to the production of potent extracellular toxins. The biochemical mechanisms of action of Clostridium toxins have been extensively studied in the past ten years. However, detailed information about the regulation of toxin gene expression has only recently emerged. TcdR, BotR, TetR and UviA are now known to be related alternative RNA polymerase sigma factors that drive transcription of toxin A and toxin B genes in C. difficile, the neurotoxin genes in C. botulinum and C. tetani, and a bacteriocin gene in C. perfringens. Although the Clostridium sigma factors have some similarity to members of the ECF sigma factor group, they differ sufficiently in structure and function so that they have been assigned to a new group within the sigma(70)-family.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Bacterial Toxins / biosynthesis*
  • Bacterial Toxins / genetics
  • Bacteriocins / biosynthesis*
  • Base Sequence
  • Clostridium / metabolism*
  • Clostridium botulinum / metabolism
  • Clostridium difficile / metabolism
  • Clostridium tetani / metabolism
  • DNA-Directed RNA Polymerases / metabolism*
  • Gene Expression Regulation, Bacterial
  • Molecular Sequence Data
  • Sigma Factor / metabolism*


  • Bacterial Toxins
  • Bacteriocins
  • Sigma Factor
  • DNA-Directed RNA Polymerases