Transcriptional inhibition of the inducible nitric oxide synthase gene by competitive binding of NF-kappa B/Rel proteins

Biochem Biophys Res Commun. 1995 Apr 6;209(1):73-9. doi: 10.1006/bbrc.1995.1472.


The activity of the inducible nitric oxide synthase enzyme (iNOS) is tightly controlled, partly at the transcriptional level. We find NF-kappa B/Rel activation (p50-p50 and p50-p65) in RAW 264.7 macrophages after lipopolysaccharide treatment and binding to both NF-kappa B sites in the mouse iNOS promoter. To delineate the importance of NF-kappa B/Rel in iNOS gene transcription, we used an unusually direct approach to try to improve on the antioxidant-treatment or reporter techniques, namely the depletion of NF-kappa B/Rel activity through the use of a phosphorothioate-modified oligonucleotide containing three copies of the NF-kappa B consensus sequence. The reduction in NF-kappa B/Rel activity (particularly that binding to the downstream of the two sites) was associated with a 50% reduction in NO output and a reduction in the quantity of the iNOS protein expressed. These results point to the probability that physiologically relevant NF-kappa B/Rel activators or repressors other than lipopolysaccharide might crucially affect the macrophage NO response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Oxidoreductases / genetics*
  • Amino Acid Oxidoreductases / metabolism
  • Animals
  • Base Sequence
  • Binding, Competitive
  • Gene Expression Regulation, Enzymologic
  • Mice
  • Molecular Sequence Data
  • NF-kappa B / metabolism*
  • NF-kappa B p50 Subunit
  • Nitric Oxide Synthase
  • Oligodeoxyribonucleotides
  • Transcription Factor RelA
  • Transcription Factors / metabolism
  • Transcription, Genetic*


  • NF-kappa B
  • NF-kappa B p50 Subunit
  • Oligodeoxyribonucleotides
  • Transcription Factor RelA
  • Transcription Factors
  • Nitric Oxide Synthase
  • Amino Acid Oxidoreductases