title: Maintenance of undifferentiated state and self-renewal of embryonic neural stem cells by Polycomb protein Ring1B.
abstract: Cell lineages generated during development and tissue maintenance are derived from self-renewing stem cells by differentiation of their committed progeny. Recent studies suggest that epigenetic mechanisms, and in particular the Polycomb group (PcG) of genes, play important roles in controlling stem cell self-renewal. Here, we address PcG regulation of stem cell self-renewal and differentiation through inactivation of Ring1B, a histone H2A E3 monoubiquitin ligase, in embryonic neural stem cells (NSCs) from the olfactory bulb of a conditional mouse mutant line. We show that neural stem/progenitor cell proliferation in vivo and in neurosphere assays is impaired, lacking Ring1B, and their self-renewal and multipotential abilities, assessed as sphere formation and differentiation from single cells, are severely affected. We also observed unscheduled neuronal, but not glial, differentiation of mutant stem/progenitor cells under proliferating conditions, an alteration enhanced in cells also lacking Ring1A, the Ring1B paralog, some of which turned into morphologically identifiable neurons. mRNA analysis of mutant cells showed upregulation of some neuronal differentiation-related transcription factors and the cell proliferation inhibitor Cdkn1a/p21, as well as downregulation of effectors of the Notch signaling pathway, a known inhibitor of neuronal differentiation of stem/progenitor cells. In addition, differentiation studies of Ring1B-deficient progenitors showed decreased oligodendrocyte formation in vitro and enhanced neurogenesis and reduced gliogenesis in vivo. These data suggest a role for Ring1B in maintenance of the undifferentiated state of embryonic neural stem/progenitor cells. They also suggest that Ring1B may modulate the differentiation potential of NSCs to neurons and glia.
authors: Cell and Developmental Biology, Centro de Investigaciones Biológicas, Instituto Cajal, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors: Mónica
authors: M
authors: Román-Trufero
authors: Héctor R
authors: HR
authors: Méndez-Gómez
authors: Claudia
authors: C
authors: Pérez
authors: Atsushi
authors: A
authors: Hijikata
authors: Yu-ichi
authors: Y
authors: Fujimura
authors: Takaho
authors: T
authors: Endo
authors: Haruhiko
authors: H
authors: Koseki
authors: Carlos
authors: C
authors: Vicario-Abejón
authors: Miguel
authors: M
authors: Vidal
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D009830:Olfactory Bulb / Q000166:cytology; D020411:Oligonucleotide Array Sequence Analysis; D063150:Polycomb Repressive Complex 1; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044767:Ubiquitin-Protein Ligases
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1; C489842:Rnf2 protein, mouse; D044767:Ubiquitin-Protein Ligases