Redox activation of Fos-Jun DNA binding activity is mediated by a DNA repair enzyme

EMBO J. 1992 Sep;11(9):3323-35.


The DNA binding activity of Fos and Jun is regulated in vitro by a post-translational mechanism involving reduction-oxidation. Redox regulation occurs through a conserved cysteine residue located in the DNA binding domain of Fos and Jun. Reduction of this residue by chemical reducing agents or by a ubiquitous nuclear redox factor (Ref-1) recently purified from Hela cells, stimulates AP-1 DNA binding activity in vitro, whereas oxidation or chemical modification of the cysteine has an inhibitory effect on DNA binding activity. Here we demonstrate that the protein product of the ref-1 gene stimulates the DNA binding activity of Fos-Jun heterodimers, Jun-Jun homodimers and Hela cell AP-1 proteins as well as that of several other transcription factors including NF-kappa B, Myb and members of the ATF/CREB family. Furthermore, immunodepletion analysis indicates that Ref-1 is the major AP-1 redox activity in Hela nuclear extracts. Interestingly, Ref-1 is a bifunctional protein; it also possesses an apurinic/apyrimidinic (AP) endonuclease DNA repair activity. However, the redox and DNA repair activities of Ref-1 can, in part, be distinguished biochemically. This study suggests a novel link between transcription factor regulation, oxidative signalling and DNA repair processes in higher eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA / metabolism*
  • DNA Repair / physiology*
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • DNA-Binding Proteins / metabolism*
  • Deoxyribonuclease IV (Phage T4-Induced)
  • Endodeoxyribonucleases / genetics
  • Endodeoxyribonucleases / metabolism
  • Escherichia coli
  • Escherichia coli Proteins*
  • Fluorescent Antibody Technique
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism*
  • Oxidation-Reduction
  • Proto-Oncogene Proteins c-fos / metabolism*
  • Proto-Oncogene Proteins c-jun / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Nucleic Acid
  • Trans-Activators*
  • Transcription Factors / metabolism


  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • HAP1 protein, S cerevisiae
  • Nuclear Proteins
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • Transcription Factors
  • DNA
  • Endodeoxyribonucleases
  • Deoxyribonuclease IV (Phage T4-Induced)
  • endonuclease IV, E coli
  • APEX1 protein, human
  • DNA-(Apurinic or Apyrimidinic Site) Lyase

Associated data

  • GENBANK/S43127
  • GENBANK/X66121
  • GENBANK/X66358
  • GENBANK/X66359
  • GENBANK/X66360
  • GENBANK/X66361
  • GENBANK/X66362
  • GENBANK/X66363
  • GENBANK/X66364
  • GENBANK/X66365