Redox modulation of AP-2 DNA binding activity in vitro.
Transcription factor AP-2 plays a critical role in regulating gene expression during vertebrate development and cellular differentiation. We report here that AP-2 DNA binding in vitro can be reversibly modulated by redox conditions and that thioredoxin is a potent stimulator of AP-2 DNA binding. Our studies indicate that oxidation of recombinant human AP-2 with diamide or hydrogen peroxide inhibits its DNA binding activity to synthetic AP-2 oligodeoxynucleotides. The inhibitory effect of diamide on AP-2 DNA binding was dose-dependent and was reversible by addition of reducing agents beta-mercaptoethanol, dithiothreitol, and thioredoxin. Immunoblot assays indicated that treatment with oxidants caused a change in migration of the AP-2 protein in nonreducing gels and that this effect was also reversible by treatment of the oxidized AP-2 with reducing agents. These data suggest a mechanism by which the oxidation state of conserved cysteine residues in the AP-2 DNA binding domain may contribute to its DNA binding activity. AP-2 joins a group of other transcription factors whose functions are regulated in part by their redox states.
Huang
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Radiation and Free Radical Biology Graduate Program, University of Iowa, Iowa City, Iowa, 52242, USA.
Domann
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D000818:Animals; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D003958:Diamide / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008623:Mercaptoethanol / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019163:Reducing Agents / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013879:Thioredoxins / Q000494:pharmacology; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D019163:Reducing Agents; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D003958:Diamide; D013879:Thioredoxins; D008623:Mercaptoethanol; D004247:DNA; D006861:Hydrogen Peroxide; D004229:Dithiothreitol