A pleiotropic element in the medium-chain acyl coenzyme A dehydrogenase gene promoter mediates transcriptional regulation by multiple nuclear receptor transcription factors and defines novel receptor-DNA binding motifs.
We previously identified a complex regulatory element in the medium-chain acyl coenzyme A dehydrogenase gene promoter that confers transcriptional regulation by the retinoid receptors RAR and RXR and the orphan nuclear receptor HNF-4. In this study we demonstrate a trans-repressing regulatory function for the orphan receptor COUP-TF at this same nuclear receptor response element (NRRE-1). The transcriptional regulatory properties and receptor binding sequences of each nuclear receptor response element within NRRE-1 are also characterized. NRRE-1 consists of four potential nuclear hormone receptor hexamer binding sites, arranged as [<--1-(n)s-2-->-3-->(n)4<--4], three of which are used in alternative pairwise binding by COUP-TF and HNF-4 homodimers and by RAR-RXR heterodimers, as demonstrated by mobility shift assays and methylation interference analysis. Binding and transactivation studies with mutant NRRE-1 elements confirmed the existence of distinct retinoid, COUP-TF, and HNF-4 response elements that define novel receptor binding motifs: COUP-TF homodimers bound sites 1 and 3 (two hexamer repeat sequences arranged as an everted imperfect repeat separated by 14 bp or ER14), RAR-RXR heterodimers bound sites 1 and 2 (ER8), and HNF-4 homodimers bound sites 2 and 3 (imperfect DR0). Mixing cotransfection experiments demonstrated that the nuclear receptor dimers compete at NRRE-1 to modulate constitutive and ligand-mediated transcriptional activity. These data suggest a mechanism for the transcriptional modulation of genes encoding enzymes involved in cellular metabolism.
Carter
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ME
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Gulick
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T
Moore
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Kelly
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D042964:Acyl-CoA Dehydrogenase; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051838:COUP Transcription Factor I; D002467:Cell Nucleus / Q000378:metabolism*; D002645:Chickens; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000096:biosynthesis* / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D051557:Hepatocyte Nuclear Factor 4; D006801:Humans; D008745:Methylation; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D010047:Ovalbumin / Q000235:genetics*; D010750:Phosphoproteins; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000096:biosynthesis / Q000378:metabolism; D047488:Retinoid X Receptors; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051838:COUP Transcription Factor I; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; C403128:MLX protein, human; C497589:NR2F1 protein, human; D015345:Oligonucleotide Probes; D010750:Phosphoproteins; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D010047:Ovalbumin; D044943:Fatty Acid Desaturases; D042964:Acyl-CoA Dehydrogenase; D015500:Chloramphenicol O-Acetyltransferase