title: Ring1b bookmarks genes in pancreatic embryonic progenitors for repression in adult β cells.
abstract: Polycomb-mediated gene repression is essential for embryonic development, yet its precise role in lineage-specific programming is poorly understood. Here we inactivated Ring1b, encoding a polycomb-repressive complex 1 subunit, in pancreatic multipotent progenitors (Ring1b(progKO)). This caused transcriptional derepression of a subset of direct Ring1b target genes in differentiated pancreatic islet cells. Unexpectedly, Ring1b inactivation in differentiated islet β cells (Ring1b(βKO)) did not cause derepression, even after multiple rounds of cell division, suggesting a role for Ring1b in the establishment but not the maintenance of repression. Consistent with this notion, derepression in Ring1b(progKO) islets occurred preferentially in genes that were targeted de novo by Ring1b during pancreas development. The results support a model in which Ring1b bookmarks its target genes during embryonic development, and these genes are maintained in a repressed state through Ring1b-independent mechanisms in terminally differentiated cells. This work provides novel insights into how epigenetic mechanisms contribute to shaping the transcriptional identity of differentiated lineages.
authors.affiliation: Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain.
authors.forename: Joris
authors.initials: J
authors.lastname: van Arensbergen
authors.forename: Javier
authors.initials: J
authors.lastname: García-Hurtado
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Maestro
authors.forename: Miguel
authors.initials: M
authors.lastname: Correa-Tapia
authors.forename: Guy A
authors.initials: GA
authors.lastname: Rutter
authors.forename: Miguel
authors.initials: M
authors.lastname: Vidal
authors.forename: Jorge
authors.initials: J
authors.lastname: Ferrer
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D019175:DNA Methylation; D004622:Embryo, Mammalian; D044127:Epigenesis, Genetic; D018507:Gene Expression Regulation, Developmental; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D009474:Neurons / Q000378:metabolism; D063150:Polycomb Repressive Complex 1 / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D063150:Polycomb Repressive Complex 1; C489842:Rnf2 protein, mouse; D044767:Ubiquitin-Protein Ligases