Thyroid hormone up-regulates NGFI-A gene expression in rat brain during development.
NGFI-A is an immediate-early response gene induced by signals that initiate growth and differentiation. Its mRNA encodes a sequence-specific transcriptional activator possibly implicated in the control of brain developmental processes. Due to the essential role of thyroid hormone for a correct brain development, we have now investigated the possible regulation by 3,5,3'-triiodo-L-thyronine (T3) of NGFI-A gene expression during maturation of the central nervous system. Our results indicate that expression of mRNA encoding NGFI-A transcription factor is about 8-fold decreased in the brain of neonatal hypothyroid rats. No changes were seen when hypothyroidism was induced in adult life. T3 treatment increased NGFI-A mRNA within 1 h, suggesting that thyroid hormone effect is likely to be a direct one. These data indicate a strong regulation by thyroid hormone of the expression of the growth factor inducible gene NGFI-A during brain development, making this gene a suitable model to study T3 action in the early developing nervous system.
Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
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Pipaon
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Santos
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Perez-Castillo
D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D051766:Early Growth Response Protein 1; D005260:Female; D005786:Gene Expression Regulation; D007037:Hypothyroidism / Q000378:metabolism; D017874:Immediate-Early Proteins; D008297:Male; D011247:Pregnancy; D012313:RNA / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014284:Triiodothyronine / Q000502:physiology*; D015854:Up-Regulation
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D014157:Transcription Factors; D014284:Triiodothyronine; D012313:RNA