Extra Cytoplasmic Function sigma factors, recent structural insights into promoter recognition and regulation

Curr Opin Struct Biol. 2015 Feb:30:71-78. doi: 10.1016/j.sbi.2015.01.006. Epub 2015 Feb 9.


Bacterial transcription initiation is controlled by sigma factors, the RNA polymerase (RNAP) subunits responsive for promoter specificity. While the primary sigma factor ensures the bulk of transcription during growth, a major strategy used by bacteria to regulate gene expression consists of modifying the RNAP promoter specificity by means of alternative sigma factors. Among these factors, Extra Cytoplasmic Function sigma factors (σ(ECF)) constitute the most abundant group and are generally kept inactive by specific anti-sigma factors that are directly or indirectly sensitive to environmental stimuli. When activated by anti-sigma factor release, σ(ECF) turn on the transcription of dedicated regulons, which trigger adaptive responses for the survival of the cell. Recent structural studies have deciphered the molecular basis for σ(ECF) promoter recognition and original regulatory mechanisms.

Publication types

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

MeSH terms

  • Bacteria / growth & development*
  • Bacteria / metabolism
  • Gene Expression Regulation, Bacterial / drug effects
  • Gene Expression Regulation, Bacterial / genetics*
  • Models, Molecular*
  • Promoter Regions, Genetic / genetics*
  • Repressor Proteins / pharmacology*
  • Sigma Factor / antagonists & inhibitors
  • Sigma Factor / chemistry*
  • Sigma Factor / metabolism*


  • Repressor Proteins
  • Sigma Factor