Sigma S-dependent growth-phase induction of the csgBA promoter in Escherichia coli can be achieved in vivo by sigma 70 in the absence of the nucleoid-associated protein H-NS

Mol Microbiol. 1994 Sep;13(6):1021-32. doi: 10.1111/j.1365-2958.1994.tb00493.x.


The stationary-phase-specific sigma factor sigma S (RpoS/KatF) is required for Escherichia coli to induce expression of fibronectin-binding curli organelles upon reaching stationary phase. We show that the csgA gene which encodes the curlin subunit protein belongs to a dicistronic operon, csgBA. The transcriptional start site of csgBA was determined and an AT-rich up-stream activating sequence (UAS) required for transcriptional activation was identified. The pcsgBA promoter is not specific for sigma S since the same promoter sequence can be used by E sigma 70 in vivo in a strain lacking nucleoid-associated protein H-NS and sigma S. Transcription remained growth-phase induced and dependent upon the UAS in such a double mutant. Furthermore, we demonstrate that an additional operon, hdeAB, which is also dependent upon sigma S for transcription, can be transcribed by E sigma 70 in vivo in the absence of H-NS by utilizing the phdeAB promoter. Two other genes known to be under the control of sigma S for expression, bolA and katE, remained transcriptionally silent in the absence of H-NS. It is suggested that a subset of E. coli promoters can be recognized by both E sigma S and E sigma 70 in vivo but H-NS interacting with these sequences prevents formation of successful transcription-initiation complexes with E sigma 70.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / physiology*
  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / physiology*
  • Base Sequence
  • Catalase / biosynthesis
  • Catalase / genetics
  • DNA-Binding Proteins / physiology*
  • DNA-Directed RNA Polymerases / physiology*
  • Escherichia coli / genetics*
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial
  • Molecular Sequence Data
  • Operon
  • Promoter Regions, Genetic*
  • Sigma Factor / physiology*


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • H-NS protein, bacteria
  • Sigma Factor
  • csgA protein, E coli
  • hdeA protein, E coli
  • hdeB protein, E coli
  • sigma factor KatF protein, Bacteria
  • Crl protein, Bacteria
  • Catalase
  • RNA polymerase sigma 70
  • DNA-Directed RNA Polymerases