Molecular basis distinguishing the DNA binding profile of Nrf2-Maf heterodimer from that of Maf homodimer.
Nrf2-small Maf heterodimer activates the transcription of many cytoprotective genes through the antioxidant response element and serves as a key factor in xenobiotic and oxidative stress responses. Our surface plasmon resonance-microarray binding analysis revealed that both Nrf2-MafG heterodimer and MafG homodimer bind to the consensus Maf recognition element with high affinity but bind differentially to the suboptimal binding sequences degenerated from the consensus. We examined the molecular basis distinguishing the binding profile of Nrf2-MafG heterodimer from that of MafG homodimer and found that the Ala-502 residue in the basic region of Nrf2 is a critical determinant of its binding specificity. In Maf proteins, a tyrosine resides in the position corresponding to Ala-502 in Nrf2. We prepared a mutant Nrf2 molecule in which Ala-502 was replaced with tyrosine. In surface plasmon resonance-microarray analysis, heterodimer of Nrf2(A502Y) and MafG displayed a binding specificity similar to that of MafG homodimer. The target genes activated by mutant Nrf2(A502Y)-small Maf heterodimer were largely different, albeit with some overlap, from those activated by wild-type Nrf2-small Maf, indicating that the array of target genes regulated by Nrf2-small Maf heterodimer differs substantially from that regulated by Maf homodimer in vivo. These results suggest that the distinct DNA binding profile of Nrf2-Maf heterodimer is biologically significant for Nrf2 to function as a key regulator of cytoprotective genes. Our contention is supported that the differential DNA binding specificity between Maf homodimers and Nrf2-Maf heterodimers establishes the differential gene regulation by these dimer-forming transcription factors.
Kimura
Momoko
M
Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572; Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575.
Yamamoto
Tae
T
Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572.
Zhang
Jianyong
J
Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572.
Itoh
Ken
K
Department of Stress Response Science, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562.
Kyo
Motoki
M
Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572; TOYOBO Co. Ltd. Biotechnology Frontier Project, 10-24 Toyo-Cho, Tsuruga, 914-0047.
Kamiya
Terue
T
TOYOBO Co. Ltd. Biotechnology Frontier Project, 10-24 Toyo-Cho, Tsuruga, 914-0047.
Aburatani
Hiroyuki
H
Research Center for Advance Science and Technology, University of Tokyo, Tokyo 153-8904.
Katsuoka
Fumiki
F
Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572.
Kurokawa
Hirofumi
H
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577.
Tanaka
Toshiyuki
T
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8572.
Motohashi
Hozumi
H
Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575; Environmental Response Project, Exploratory Research for Advanced Technology-Japan Science and Technology Corp. (ERATO-JST), Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575, Japan.
Yamamoto
Masayuki
M
Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575; Environmental Response Project, Exploratory Research for Advanced Technology-Japan Science and Technology Corp. (ERATO-JST), Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575, Japan. Electronic address: hozumim@mail.tains.tohoku.ac.jp.
D000595:Amino Acid Sequence; D004247:DNA / Q000737:chemistry*; D019281:Dimerization; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics; D051259:MafG Transcription Factor / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D051267:NF-E2-Related Factor 2 / Q000737:chemistry* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011485:Protein Binding; D051257:Proto-Oncogene Proteins c-maf / Q000737:chemistry* / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance; D014443:Tyrosine / Q000737:chemistry
C495607:MAF protein, human; C103944:MAFG protein, human; D051259:MafG Transcription Factor; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D051257:Proto-Oncogene Proteins c-maf; D012097:Repressor Proteins; D014443:Tyrosine; D004247:DNA