Genetic evidence that small maf proteins are essential for the activation of antioxidant response element-dependent genes.
While small Maf proteins have been suggested to be essential for the Nrf2-mediated activation of antioxidant response element (ARE)-dependent genes, the extent of their requirement remains to be fully documented. To address this issue, we generated mafG::mafF double-mutant mice possessing MafK as the single available small Maf. Induction of the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene was significantly impaired in double-mutant mice treated with butylated hydroxyanisole, while other ARE-dependent genes were less affected. Similarly, in a keap1-null background, where many of the ARE-dependent genes are constitutively activated in an Nrf2-dependent manner, only a subset of ARE-dependent genes, including NQO1, were sensitive to a simultaneous deficiency in MafG and MafF. Examination of single and double small maf mutant cells revealed that MafK also contributes to the induction of ARE-dependent genes. To obtain decisive evidence, we established mafG::mafK::mafF triple-mutant fibroblasts that completely lack small Mafs and turned out to be highly susceptible to oxidative stress. We found that induction in response to diethyl maleate was abolished in a wider range of ARE-dependent genes in the triple-mutant cells. These data explicitly demonstrate that small Mafs play critical roles in the inducible expression of a significant portion of ARE-dependent genes.
Katsuoka
Fumiki
F
Center for TARA, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan.
Motohashi
Hozumi
H
Ishii
Tetsuro
T
Aburatani
Hiroyuki
H
Engel
James Douglas
JD
Yamamoto
Masayuki
M
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004622:Embryo, Mammalian / Q000166:cytology; D050981:Erythroid-Specific DNA-Binding Factors; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D000072019:Kelch-Like ECH-Associated Protein 1; D051260:MafF Transcription Factor; D051259:MafG Transcription Factor; D050985:MafK Transcription Factor; D008298:Maleates / Q000494:pharmacology; D051379:Mice; D008817:Mice, Mutant Strains; D016660:NAD(P)H Dehydrogenase (Quinone); D009252:NADPH Dehydrogenase / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D020218:Response Elements / Q000187:drug effects / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; D000975:Antioxidants; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; C117301:Keap1 protein, mouse; D000072019:Kelch-Like ECH-Associated Protein 1; D051260:MafF Transcription Factor; D051259:MafG Transcription Factor; D050985:MafK Transcription Factor; C484146:Maff protein, mouse; C491247:Mafg protein, mouse; C494696:Mafk protein, mouse; D008298:Maleates; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D016660:NAD(P)H Dehydrogenase (Quinone); C491732:Nqo1 protein, mouse; D009252:NADPH Dehydrogenase