The transcriptional regulator RfaH stimulates RNA chain synthesis after recruitment to elongation complexes by the exposed nontemplate DNA strand.
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.
Artsimovitch
Irina
I
Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA.
Landick
Robert
R
D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics*; D010441:Peptide Chain Elongation, Translational / Q000235:genetics*; D010445:Peptide Elongation Factors / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012329:RNA, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D013698:Templates, Genetic; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; D012329:RNA, Bacterial; C106401:RfaH protein, E coli; D015534:Trans-Activators