The murine Dax-1 promoter is stimulated by SF-1 (steroidogenic factor-1) and inhibited by COUP-TF (chicken ovalbumin upstream promoter-transcription factor) via a composite nuclear receptor-regulatory element.
The Dax-1 gene encodes a protein that is structurally related to members of the orphan nuclear receptor superfamily. Dax-1 is coexpressed with another orphan nuclear receptor, steroidogenic factor-1 (SF-1), in the adrenal, gonads, hypothalamus, and pituitary gland. Mutations in Dax-1 cause adrenal hypoplasia congenita, a disorder that is characterized by adrenal insufficiency and hypogonadotropic hypogonadism. These developmental and endocrine abnormalities are similar to those caused by disruption of the murine Ftz-F1 gene (which encodes SF-1), suggesting that these nuclear receptors act along the same developmental cascade. Cloning of the murine Dax-1 gene revealed a candidate SF-1-binding site in the Dax-1 promoter. In transient expression assays in SF-1-deficient JEG-3 cells, SF-1 stimulated expression of the Dax-1 promoter. However, deletion or mutation of the consensus SF-1-binding site did not eliminate SF-1 stimulation. Further analyses revealed the presence of a cryptic SF-1 site that creates an imperfect direct repeat of the SF-1 element. When linked to the minimal thymidine kinase promoter, each of the isolated SF-1 sites was sufficient to mediate transcriptional regulation by SF-1. Mutation of both SF-1 sites eliminated SF-1 binding and stimulation of the Dax-1 promoter. Unexpectedly, mutation of either half of the composite SF-1 sites increased basal activity in JEG-3 cells, suggesting interaction of a repressor protein. Gel shift analyses of the composite response element revealed an additional complex that was not supershifted by SF-1 antibodies. This complex was eliminated by mutation of either half-site, and it was supershifted by antibodies against chicken ovalbumin upstream promoter-transcription factor (COUP-TF). We propose that Dax-1 is stimulated by SF-1, and that SF-1 and COUP-TF provide antagonistic pathways that converge upon a common regulatory site.
Yu
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RN
Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Ito
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Jameson
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JL
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D051838:COUP Transcription Factor I; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002822:Choriocarcinoma / Q000378:metabolism; D057137:DAX-1 Orphan Nuclear Receptor; D004247:DNA / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology*; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010920:Placenta / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; D013937:Thymidine Kinase / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology*; D014407:Tumor Cells, Cultured
D051838:COUP Transcription Factor I; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C539965:NR0B1 protein, human; C497589:NR2F1 protein, human; C515057:NR5A1 protein, human; C539966:Nr0b1 protein, mouse; C497590:Nr2f1 protein, mouse; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse; D004247:DNA; D013937:Thymidine Kinase