Nestin is a neuroepithelial target gene of thyroid transcription factor-1, a homeoprotein required for forebrain organogenesis.
Thyroid transcription factor-1 (TTF-1, also known as NKX2.1 and T/EBP), a transcription factor belonging to the NKX-2 family of homeodomain-containing genes, plays an essential role in the organogenesis of the thyroid gland, lung, and ventral forebrain. Nestin is an intermediate filament protein strongly expressed in multipotential neuroepithelial stem cells and rapidly down-regulated during postnatal life. Here we show that stable fibroblastic clones expressing TTF-1 acquire a phenotype reminiscent of neuroepithelial cells in culture and up-regulate the endogenous nestin gene. TTF-1 transactivates in HeLa and NIH3T3 cells a reporter gene driven by a central nervous system-specific enhancer element from the second intron of the rat nestin gene, where it recognizes a DNA-binding site (NestBS) whose sequence resembles a nuclear hormone/cAMP-responsive element very different from canonical TTF-1 binding sites. Nuclear extracts from the head of mouse embryos form a retarded complex with NestBS of the same mobility of the extracts obtained from TTF1-expressing clones, which is either abolished or supershifted in the presence of two different antibodies recognizing the TTF-1 protein. Thus, the neuroepithelial marker nestin is a direct central nervous system-specific target gene of TTF-1, leading to the hypothesis that it might be the effector through which TTF-1 plays its role in the organogenesis of the forebrain.
Lonigro
R
R
Department of Biology and Biotechnology, S. Raffaele Scientific Institute, Via Olgettina, 58, Milano 20132, Italy.
Donnini
D
D
Zappia
E
E
Damante
G
G
Bianchi
M E
ME
Guazzi
S
S
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D017931:DNA Primers; D004742:Enhancer Elements, Genetic; D004848:Epithelium / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism*; D007381:Intermediate Filament Proteins / Q000235:genetics*; D051379:Mice; D009024:Morphogenesis; D009419:Nerve Tissue Proteins; D064231:Nestin; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D016548:Prosencephalon / Q000196:embryology*; D011485:Protein Binding; D051381:Rats; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D017931:DNA Primers; D018398:Homeodomain Proteins; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; C577486:Nes protein, rat; D064231:Nestin; C000614414:Nkx2-1 protein, mouse; C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors