Abstract
Self-renewal of human embryonic stem cells (ESCs) is promoted by FGF and TGFbeta/Activin signaling, and differentiation is promoted by BMP signaling, but how these signals regulate genes critical to the maintenance of pluripotency has been unclear. Using a defined medium, we show here that both TGFbeta and FGF signals synergize to inhibit BMP signaling; sustain expression of pluripotency-associated genes such as NANOG, OCT4, and SOX2; and promote long-term undifferentiated proliferation of human ESCs. We also show that both TGFbeta- and BMP-responsive SMADs can bind with the NANOG proximal promoter. NANOG promoter activity is enhanced by TGFbeta/Activin and FGF signaling and is decreased by BMP signaling. Mutation of putative SMAD binding elements reduces NANOG promoter activity to basal levels and makes NANOG unresponsive to BMP and TGFbeta signaling. These results suggest that direct binding of TGFbeta/Activin-responsive SMADs to the NANOG promoter plays an essential role in sustaining human ESC self-renewal.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Benzamides / pharmacology
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Bone Morphogenetic Proteins / antagonists & inhibitors
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Bone Morphogenetic Proteins / genetics
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Cell Differentiation / drug effects
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Cell Differentiation / genetics
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Cell Line
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Cell Proliferation / drug effects
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Dioxoles / pharmacology
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Embryonic Stem Cells / cytology
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Embryonic Stem Cells / metabolism*
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Fibroblast Growth Factors / genetics
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Fibroblast Growth Factors / pharmacology
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Homeodomain Proteins / genetics*
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Humans
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Lymphotoxin-alpha / genetics*
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Lymphotoxin-alpha / pharmacology
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Nanog Homeobox Protein
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Promoter Regions, Genetic
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Protein Binding / drug effects
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Recombinant Proteins / genetics
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Recombinant Proteins / pharmacology
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Signal Transduction / drug effects
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Signal Transduction / genetics
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Smad2 Protein / antagonists & inhibitors
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Smad2 Protein / genetics*
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Smad3 Protein / antagonists & inhibitors
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Smad3 Protein / genetics*
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Transcriptional Activation / drug effects
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Transcriptional Activation / genetics
Substances
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4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide
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Benzamides
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Bone Morphogenetic Proteins
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Dioxoles
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Homeodomain Proteins
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Lymphotoxin-alpha
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NANOG protein, human
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Nanog Homeobox Protein
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Recombinant Proteins
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Smad2 Protein
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Smad3 Protein
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Fibroblast Growth Factors