Dual requirement for the EcR/USP nuclear receptor and the dGATAb factor in an ecdysone response in Drosophila melanogaster.
The EcR/USP nuclear receptor controls Drosophila metamorphosis by activating complex cascades of gene transcription in response to pulses of the steroid hormone ecdysone at the end of larval development. Ecdysone release provides a ubiquitous signal for the activation of the receptor, but a number of its target genes are induced in a tissue- and stage-specific manner. Little is known about the molecular mechanisms involved in this developmental modulation of the EcR/USP-mediated pathway. Fbp1 is a good model of primary ecdysone response gene expressed in the fat body for addressing this question. We show here that the dGATAb factor binds to three target sites flanking an EcR/USP binding site in a 70-bp enhancer that controls the tissue and stage specificity of Fbp1 transcription. We demonstrate that one of these sites and proper expression of dGATAb are required for specific activation of the enhancer in the fat body. In addition, we provide further evidence that EcR/USP plays an essential role as a hormonal timer. Our study provides a striking example of the integration of molecular pathways at the level of a tissue-specific hormone response unit.
Institut Jacques Monod, Laboratoire de Biologie du Développement, CNRS UMR 7592, Université Paris 7 Denis-Diderot, Université Paris 6 P. et M. Curie, 75251 Paris Cedex 05, France.
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Brodu
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Mugat
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Roignant
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Lepesant
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Antoniewski
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000502:physiology*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D004440:Ecdysone / Q000494:pharmacology*; D004742:Enhancer Elements, Genetic; D005216:Fat Body / Q000378:metabolism; D005656:Fungal Proteins / Q000502:physiology; D050980:GATA Transcription Factors; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014157:Transcription Factors / Q000502:physiology*
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C087777:Fbp1protein, Drosophila; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D050980:GATA Transcription Factors; D019476:Insect Proteins; D046911:Macromolecular Substances; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C066030:USP protein, Drosophila; C103965:srp protein, Drosophila; D004440:Ecdysone