SF-1 (steroidogenic factor-1), C/EBPbeta (CCAAT/enhancer binding protein), and ubiquitous transcription factors NF1 (nuclear factor 1) and Sp1 (selective promoter factor 1) are required for regulation of the mouse aldose reductase-like gene (AKR1B7) expression in adrenocortical cells.
The MVDP (mouse vas deferens protein) gene encodes an aldose reductase-like protein (AKR1B7) that is responsible for detoxifying isocaproaldehyde generated by steroidogenesis. In adrenocortical cell cultures, hormonal regulation of MVDP gene occurs through the cAMP pathway. We show that in adrenals, the pituitary hormone ACTH regulates MVDP gene expression in a coordinate fashion with steroidogenic genes. Cell transfection and DNA-binding studies were used to investigate the molecular mechanisms underlying MVDP gene regulation in Y1 adrenocortical cells. Progressive deletions of upstream regulatory regions identified a -121/+41 fragment that was sufficient for basal and cAMP-mediated transcriptional activities. Gel shift assays showed that CTF1/nuclear factor 1 (NF1), CCAAT enhancer binding protein-ss (C/EBPss), and selective promoter factor 1 (Sp1) factors bound to cis-acting elements at positions -76, -61, and -52, respectively. We report that the cell-specific steroidogenic factor-1 (SF-1) interacts specifically with a novel regulatory element located in the downstream half-site of the proximal androgen response element (AREp) at position -102. Functional analysis of SF-1 and NF1 sites in the -121/+41 promoter showed that mutation of one of them decreases both constitutive and forskolin-stimulated promoter activity without affecting the fold induction (forskolin stimulated/basal). Individual mutations of C/EBP and Sp1 sites resulted in a loss of more than 50% of the cAMP-dependent induction. When both sites were mutated simultaneously, cAMP responsiveness was nearly abolished. Thus, in adrenocortical cells, both SF-1 and NF1 are required for high expression of the MVDP promoter while Sp1 and C/EBPss functionally interact in an additive manner to mediate cAMP-dependent regulation. Furthermore, we report that MVDP gene regulation is impaired in stably transfected Y1 clones expressing DAX-1. Taken together, our findings suggest that detoxifying enzymes of the aldose reductase family may constitute new potential targets for regulators of adrenal and gonadal differentiation and function, e.g. SF-1 and DAX-1.
Aigueperse
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UMR Centre National de la Recherche Scientifique 6547 Physiologie Comparée et Endocrinologie Moléculaire, Université Blaise Pascal Clermont II, Complexe Universitaire des Cézeaux 63177 Aubière cedex, France.
Val
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Pacot
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Darne
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Lalli
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Sassone-Corsi
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Veyssiere
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Jean
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Martinez
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D000302:Adrenal Cortex / Q000201:enzymology*; D000449:Aldehyde Reductase / Q000235:genetics*; D000074408:Aldo-Keto Reductases; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D057137:DAX-1 Orphan Nuclear Receptor; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D051717:Fushi Tarazu Transcription Factors; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018398:Homeodomain Proteins; D008297:Male; D051379:Mice; D016297:Mutagenesis, Site-Directed; D051839:NFI Transcription Factors; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D054339:Steroidogenic Factor 1; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*
D022762:CCAAT-Enhancer-Binding Proteins; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D051839:NFI Transcription Factors; C539965:NR0B1 protein, human; C515057:NR5A1 protein, human; C539966:Nr0b1 protein, mouse; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse; C080333:transcription factor nuclear factor 1; D005576:Colforsin; D004247:DNA; D000242:Cyclic AMP; C120471:AKR1B10 protein, human; D000074408:Aldo-Keto Reductases; D000449:Aldehyde Reductase