title: The cell cycle inhibitor p27Kip¹ controls self-renewal and pluripotency of human embryonic stem cells by regulating the cell cycle, Brachyury and Twist.
abstract: The continued turn over of human embryonic stem cells (hESC) while maintaining an undifferentiated state is dependent on the regulation of the cell cycle. Here we asked the question if a single cell cycle gene could regulate the self-renewal or pluripotency properties of hESC. We identified that the protein expression of the p27(Kip)¹ cell cycle inhibitor is low in hESC cells and increased with differentiation. By adopting a gain and loss of function strategy we forced or reduced its expression in undifferentiating conditions to define its functional role in self-renewal and pluripotency. Using undifferentiation conditions, overexpression of p27(Kip)¹ in hESC lead to a G₁phase arrest with an enlarged and flattened hESC morphology and consequent loss of self-renewal ability. Loss of p27(Kip)¹ caused an elongated/scatter cell-like phenotype involving up-regulation of Brachyury and Twist gene expression. We demonstrate the novel finding that p27(Kip)¹ protein occupies the Twist1 gene promoter and manipulation of p27(Kip)¹ by gain and loss of function is associated with Twist gene expression changes. These results define p27(Kip)¹ expression levels as critical for self-renewal and pluripotency in hESC and suggest a role for p27(Kip)¹ in controlling an epithelial to mesenchymal transition (EMT) in hESC.
authors.affiliation: Center of Regenerative Medicine in Barcelona; Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Menchón
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Edel
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Izpisua Belmonte
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis / Q000172:deficiency / Q000502:physiology*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism* / Q000502:physiology; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology; D005326:Fetal Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D055785:Gene Knockdown Techniques / Q000379:methods; D006131:Growth Inhibitors / Q000502:physiology*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000502:physiology; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020825:T-Box Domain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000235:genetics; D000098908:Brachyury Protein
chemical_list: D050760:Cyclin-Dependent Kinase Inhibitor p27; D005326:Fetal Proteins; D006131:Growth Inhibitors; D009687:Nuclear Proteins; D020825:T-Box Domain Proteins; D051879:Twist-Related Protein 1; D000098908:Brachyury Protein; C436291:CDKN1B protein, human; C103173:TWIST1 protein, human