1. Chicken ovalbumin upstream promoter-transcription factor (COUP-TF) modulates expression of the Purkinje cell protein-2 gene. A potential role for COUP-TF in repressing premature thyroid hormone action in the developing brain.
- Author
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Anderson GW, Larson RJ, Oas DR, Sandhofer CR, Schwartz HL, Mariash CN, and Oppenheimer JH
- Subjects
- Animals, COUP Transcription Factor I, Cerebellum cytology, Chickens, Female, Guanine Nucleotide Exchange Factors, Mice, Neuropeptides biosynthesis, Nucleoproteins physiology, Ovalbumin, Pregnancy, Promoter Regions, Genetic, Rats, Rats, Sprague-Dawley, Trans-Activators physiology, Cerebellum embryology, DNA-Binding Proteins physiology, Embryonic and Fetal Development genetics, Gene Expression Regulation, Developmental, Neuropeptides genetics, Purkinje Cells metabolism, Transcription Factors physiology, Triiodothyronine physiology
- Abstract
The cerebellar Purkinje cell-specific PCP-2 gene is transcriptionally activated by thyroid hormone during the 2nd and 3rd weeks of postnatal life in the rat. In contrast, thyroid hormone has no detectable effects on PCP-2 expression in the fetal rat. We now present data that suggest that the orphan nuclear receptor chicken ovalbumin upstream promoter-transcription factor (COUP-TF) represses triiodothyronine (T3)-dependent transcriptional activation of PCP-2 in the immature Purkinje cell. Gel shift assays show that the PCP-2 A1TRE and adjoining sequences (-295/-199 region) bind to rat and mouse brain nucleoproteins in a developmentally regulated fashion and that one of these nucleoproteins could be the orphan nucleoprotein COUP-TF. In support of this hypothesis, in vitro translated COUP-TF binds to the -295/-199 region and COUP-TF represses T3-dependent activation of the PCP-2 promoter in transient transfection analyses. Finally, immunohistochemical studies reveal that COUP-TF is specifically expressed in the immature fetal and early neonatal Purkinje cell and that this expression diminishes coincident with thyroid hormone induction of PCP-2 expression. Our findings are consistent with the hypothesis that the presence or absence of inhibitory proteins bound to the thyroid hormone response element of T3-responsive genes governs the responsivity of these genes to thyroid hormone during brain development.
- Published
- 1998
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