Activation and repression at the Escherichia coli ynfEFGHI operon promoter

Meng Xu, Stephen J W Busby, Douglas F Browning

Research output: Contribution to journalArticlepeer-review


Induction of the Escherichia coli K-12 ynfEFGHI operon in response to anaerobiosis is repressed by nitrate ions. In this study, we show that the global transcription factor FNR is a class II activator at the ynfEFGHI promoter and that NarL represses activation by binding to a single target that overlaps the promoter -10 element. Electromobility shift assays show that NarL does not prevent RNA polymerase binding and suggest that repression may involve a quaternary NarL-FNR-RNA polymerase-promoter complex.

Original languageEnglish
Pages (from-to)3172-3176
Number of pages5
JournalJournal of Bacteriology
Issue number9
Publication statusPublished - May 2009


  • Anaerobiosis
  • Base Sequence
  • DNA-Binding Proteins/physiology
  • DNA-Directed RNA Polymerases/metabolism
  • Electrophoretic Mobility Shift Assay
  • Escherichia coli K12/genetics
  • Escherichia coli Proteins/physiology
  • Gene Expression Regulation, Bacterial
  • Iron-Sulfur Proteins/physiology
  • Molecular Sequence Data
  • Operon
  • Promoter Regions, Genetic
  • Protein Binding
  • Transcriptional Activation


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