title: Nanog induces suppression of senescence through downregulation of p27KIP1 expression.
abstract: A comprehensive analysis of the molecular network of cellular factors establishing and maintaining pluripotency as well as self renewal of pluripotent stem cells is key for further progress in understanding basic stem cell biology. Nanog is necessary for the natural induction of pluripotency in early mammalian development but dispensable for both its maintenance and its artificial induction. To gain further insight into the molecular activity of Nanog, we analyzed the outcomes of Nanog gain-of-function in various cell models employing a recently developed biologically active recombinant cell-permeant protein, Nanog-TAT. We found that Nanog enhances the proliferation of both NIH 3T3 and primary fibroblast cells. Nanog transduction into primary fibroblasts results in suppression of senescence-associated β-galactosidase activity. Investigation of cell cycle factors revealed that transient activation of Nanog correlates with consistent downregulation of the cell cycle inhibitor p27(KIP1) (also known as CDKN1B). By performing chromatin immunoprecipitation analysis, we confirmed bona fide Nanog-binding sites upstream of the p27(KIP1) gene, establishing a direct link between physical occupancy and functional regulation. Our data demonstrates that Nanog enhances proliferation of fibroblasts through transcriptional regulation of cell cycle inhibitor p27 gene.
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Münst
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany.
authors.forename: Marc Christian
authors.initials: MC
authors.lastname: Thier
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Winnemöller
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Helfen
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India frank.edenhofer@wuerzburg.de rthu@iitg.ernet.in.
authors.forename: Rajkumar P
authors.initials: RP
authors.lastname: Thummer
authors.affiliation: Stem Cell Engineering Group, Institute of Reconstructive Neurobiology, University of Bonn - Life & Brain Center and Hertie Foundation, Sigmund-Freud Str. 25, Bonn 53127, Germany Stem Cell and Regenerative Medicine Group, Institute of Anatomy and Cell Biology, Julius-Maximilians-University Würzburg, Koellikerstrasse 6, Würzburg 97070, Germany Department of Genomics, Stem Cell Biology & Regenerative Medicine, Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria frank.edenhofer@wuerzburg.de rthu@iitg.ernet.in.
authors.forename: Frank
authors.initials: F
authors.lastname: Edenhofer
mesh_terms: D000818:Animals; D001665:Binding Sites; D002448:Cell Adhesion; D049109:Cell Proliferation; D016922:Cellular Senescence; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D005347:Fibroblasts / Q000502:physiology; D015870:Gene Expression; D020868:Gene Silencing; D056426:Genetic Loci; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D000071317:Nanog Homeobox Protein / Q000502:physiology*
chemical_list: C493961:Cdkn1b protein, mouse; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050760:Cyclin-Dependent Kinase Inhibitor p27
keywords: Cell reprogramming; Embryonic stem cell; Pluripotency; Protein transduction; Senescence; p27KIP1