TTF-1/NKX2.1 up-regulates the in vivo transcription of nestin.
TTF-1/NKX2.1, also known as T/EBP, is a homeodomain-containing gene involved in the organogenesis of the thyroid gland, lung and ventral forebrain. We have already reported that in 3T3 cells, TTF-1/NKX2.1 up-regulates the transcription of nestin, an intermediate filament protein expressed in multipotent neuroepithelial cells, by direct DNA-binding to a HRE/CRE-like site (NestBS) within a CNS-specific enhancer. Here, we demonstrate that TTF-1/NKX2.1 is co-expressed with nestin in the embryonal forebrain. We also performed a transgenic mouse embryo analysis in which NestBS was replaced by the canonical TTF-1/NKX2.1 consensus DNA-binding site (as identified in many thyroid- and lung-specific genes and very divergent from NestBS) or a random mutation. We observed beta-galactosidase expression in forebrain regions where TTF-1/NKX2.1 is expressed in wild-type embryos, and -to a minor extent- in rostralmost telencephalic regions and thalamus, whereas no beta-galactosidase expression was detected in forebrains of embryos bearing the random mutation. These data show that TTF-1/NKX2.1 regulates the transcription of the nestin gene in vivo through the NestBS site, suggesting that nestin might be at least one of the effectors of TTF-1/NKX2.1 during forebrain development. Finally, we have shown that the transactivating effect of TTF-1/NKX2.1 on the CNS-specific enhancer is unaffected by Retinoic Acid Receptor-alpha.
Pelizzoli
Roberta
R
University of Genova, Department of Experimental Medicine, MicroSCoBiO Research Center, Genova, Italy.
Tacchetti
Carlo
C
Luzzi
Paola
P
Strangio
Antonella
A
Bellese
Grazia
G
Zappia
Emanuela
E
Guazzi
Stefania
S
D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005822:Genetic Vectors; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064231:Nestin; D016548:Prosencephalon / Q000196:embryology / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection
D004268:DNA-Binding Proteins; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; C000607072:Rara protein, mouse; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D015534:Trans-Activators; D014157:Transcription Factors; C504004:Ttf1 protein, mouse; D008156:Luciferases