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Sigma Factors in Gene Expression

  1. John D Helmann

Published Online: 23 SEP 2005

DOI: 10.1038/npg.els.0003829



How to Cite

Helmann, J. D. 2005. Sigma Factors in Gene Expression. eLS. .

Author Information

  1. Cornell University, Ithaca, New York, USA

Publication History

  1. Published Online: 23 SEP 2005

This is not the most recent version of the article. View current version (17 MAR 2014)


Sigma factors control the promoter selectivity of bacterial RNA polymerase. The synthesis of new sigma factors allows the coordinated activation of discrete sets of genes and thereby contributes to stress responses, motility, endospore formation, and numerous other adaptive responses.


  • RNA polymerase;
  • transcription;
  • promoter;
  • regulation