Document Detail

Transcriptional regulation of the antioxidant response element. Activation by Nrf2 and repression by MafK.
MedLine Citation:
PMID:  10747902     Owner:  NLM     Status:  MEDLINE    
The antioxidant response element (ARE) mediates the transcriptional activation of many genes encoding phase II drug-metabolizing enzymes in response to oxidative stress. Recent studies using knockout mice suggest that NF-E2-related factor 2 (Nrf2), along with small Maf proteins, binds and activates the ARE. In this study, using in vitro binding assays, Nrf2/MafK heterodimers were found to interact with high affinity to the ARE. However, distinct differences were observed when this interaction was compared with that formed with nuclear proteins from H4II EC3 or HepG2 cells. Overexpression of Nrf2 activated ARE-mediated transcription in HepG2 cells, and this activation was further increased by tert-butylhydroquinone. In HeLa cells, overexpression of Nrf2 resulted in activation of the ARE, but this activation was no longer induced by tert-butylhydroquinone. Using ARE constructs with point mutations in the core sequence, we found that only mutations at the T or G nucleotides within the core (TGAC) render the ARE unresponsive to Nrf2. Overexpression of MafK led to dose-dependent repression of ARE activity. Activation of the ARE by Nrf2 was similarly antagonized by MafK. These data suggest that Nrf2 plays an important role mediating basal activity of the ARE but that small Maf proteins are repressors and not activators of ARE-mediated transcription.
T Nguyen; H C Huang; C B Pickett
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  275     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2000 May 
Date Detail:
Created Date:  2000-06-21     Completed Date:  2000-06-21     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  15466-73     Citation Subset:  IM    
Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
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MeSH Terms
Antioxidants / pharmacology*
Base Sequence
Cell Line
Cloning, Molecular
DNA Footprinting
DNA-Binding Proteins / genetics,  metabolism*
Dimethyl Sulfoxide / pharmacology
Gene Expression Regulation* / drug effects
Gene Library
Hela Cells
Hydroquinones / pharmacology
Leucine Zippers
Liver / metabolism
MafK Transcription Factor
Molecular Sequence Data
NF-E2-Related Factor 2
Nuclear Proteins / genetics,  metabolism*
Recombinant Proteins / metabolism
Trans-Activators / genetics,  metabolism*
Transcription, Genetic* / drug effects
Tumor Cells, Cultured
Reg. No./Substance:
0/Antioxidants; 0/DNA-Binding Proteins; 0/Hydroquinones; 0/MafK Transcription Factor; 0/NF-E2-Related Factor 2; 0/NFE2L2 protein, human; 0/Nfe2l2 protein, mouse; 0/Nfe2l2 protein, rat; 0/Nuclear Proteins; 0/Recombinant Proteins; 0/Trans-Activators; 1948-33-0/2-tert-butylhydroquinone; 67-68-5/Dimethyl Sulfoxide

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