The Transcriptional Regulator RfaH Stimulates RNA Chain Synthesis After Recruitment to Elongation Complexes by the Exposed Nontemplate DNA Strand

Cell. 2002 Apr 19;109(2):193-203. doi: 10.1016/s0092-8674(02)00724-9.


The transcriptional regulatory protein RfaH controls expression of several operons that encode extracytoplasmic components in bacteria. Regulation by RfaH occurs during transcript elongation and depends on a 5'-proximal, transcribed nucleic acid sequence called ops that induces transcriptional pausing in vitro and in vivo. We report that RfaH recognizes RNA polymerase transcribing RfaH-regulated operons by interacting with the ops sequence in the exposed nontemplate DNA strand of ops-paused transcription complexes. Although RfaH delays escape from the ops pause, once escape occurs, RfaH enhances elongation by suppressing pausing and rho-dependent termination without apparent involvement of other accessory proteins. This activity predicts a cumulative antitermination model for RfaH's regulation of ops-containing operons in vivo.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacteria / genetics*
  • Bacteria / metabolism
  • Binding Sites / genetics
  • DNA, Bacterial / genetics*
  • DNA, Bacterial / metabolism
  • Escherichia coli Proteins*
  • Evolution, Molecular
  • Gene Expression Regulation, Bacterial / genetics*
  • Genes, Regulator / genetics*
  • Peptide Chain Elongation, Translational / genetics*
  • Peptide Elongation Factors / genetics*
  • Peptide Elongation Factors / metabolism
  • Phylogeny
  • RNA, Bacterial / biosynthesis*
  • RNA, Bacterial / genetics
  • Templates, Genetic*
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism
  • Transcription, Genetic / genetics


  • DNA, Bacterial
  • Escherichia coli Proteins
  • Peptide Elongation Factors
  • RNA, Bacterial
  • RfaH protein, E coli
  • Trans-Activators