Activation and repression at the Escherichia coli ynfEFGHI operon promoter

J Bacteriol. 2009 May;191(9):3172-6. doi: 10.1128/JB.00040-09. Epub 2009 Feb 27.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

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

Substances

  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • FNR protein, E coli
  • Iron-Sulfur Proteins
  • NarL protein, E coli
  • DNA-Directed RNA Polymerases