The Polycomb group (PcG) gene products mediate heritable silencing of developmental regulators in metazoans, participating in one of two distinct multimeric protein complexes, the Polycomb repressive complexes-1 (PRC1) and -2 (PRC2)1-5. PRC2 catalyses trimethylation of histone H3 at lysine 27 (H3K27) which in turn is thought to provide a recruitment site for PRC13-7. Recent studies demonstrate that mono-ubiquitylation of histone H2A at lysine 119 is important in PcG mediated silencing with the core PRC1 component Ring1A/B functioning as the E3 ligase8. PRC2 has been shown to share target genes with the core transcription network to maintain embryonic stem (ES) cells including Oct4 and Nanog9. Here we identify an essential role for PRC1 in repressing developmental regulators in ES cells, and thereby in maintaining ES cell pluripotency. A significant proportion of the PRC1 target genes are also repressed by Oct4. We demonstrate that engagement of PRC1 and PRC2 at target genes is Oct4-dependent and moreover that Ring1B interacts with Oct4. Collectively these results show that PcG complexes are instrumental in Oct4-dependent repression required to maintain pluripotency of ES cells. This study provides a first functional link between a core ES cell regulator and global epigenetic regulation of the genome.
Polycomb group proteins Ring1A/B are functionally linked to the core transcriptional regulatory circuitry to maintain ES cell identity.
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View SamplesTwo distinct Polycomb complexes, PRC1 and PRC2, collaborate to maintain epigenetic repression of key developmental loci in embryonic stem cells (ESCs). PRC1 and PRC2 have histone modifying activities, catalyzing mono-ubiquitination of histone H2A (H2AK119u1) and trimethylation of H3 lysine 27 (H3K27me3) respectively. Compared to H3K27me3, localization and role of H2AK119ub1 is not fully understood in ESCs. Here we present genome-wide H2AK119u1 maps in ESCs and identify a group of genes at which H2AK119u1 is deposited in a Ring1-dependent manner. These genes are a distinctive subset of genes with H3K27me3 enrichment and are the central targets of Polycomb silencing that are required to maintain ESC identity. We further show that the H2A ubiquitination activity of PRC1 is dispensable for its target binding and its activity to compact chromatin at Hox loci, but is indispensable for efficient repression of target genes and thereby ESC maintenance. These data demonstrate that multiple effector mechanisms including H2A ubiquitination and chromatin compaction combine to mediate PRC1-dependent repression of genes that are crucial for the maintenance of ESC identity. Utilization of these diverse effector mechanisms might provide a means to maintain a repressive state that is robust yet highly responsive to developmental cues during ES cell self-renewal and differentiation.
Histone H2A mono-ubiquitination is a crucial step to mediate PRC1-dependent repression of developmental genes to maintain ES cell identity.
Specimen part, Cell line, Treatment
View SamplesWe used microarrays to investigate the restoration of repression of PRC1 target gene expression in Ring1A/B-dKO ES cells stably expressing either of mock, WT or mutant Ring1B construct.
Histone H2A mono-ubiquitination is a crucial step to mediate PRC1-dependent repression of developmental genes to maintain ES cell identity.
Specimen part, Treatment
View SamplesIn order to explore molecules whose expression is controlled by Slc39a13, we investigated gene expression profiling of primary osteoblast isolated from wild-type and Slc39a13 knockout mice.
The zinc transporter SLC39A13/ZIP13 is required for connective tissue development; its involvement in BMP/TGF-beta signaling pathways.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Conserved principles of mammalian transcriptional regulation revealed by RNA half-life.
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View SamplesData from tc-, nt- and p-RNA as well as 1 and 2h of actinomycin-D treatment (5g/ml) of NIH-3T3 cells used to determine half-lives. RNA was labeled for 15, 30 or 60 minutes with 4-thiouridine. After preparation of tc-RNA, thiol-labeled RNA was biotinylated using biot-HPDP and subsequently tc-RNA was separated into nt- and p-RNA using streptavidin coated magnetic beads. All three fractions were used for microarray analysis. For actinomycin-D experiments only tc-RNA was used prepared from cell before and 1 an 2h after addition of act-D.
Conserved principles of mammalian transcriptional regulation revealed by RNA half-life.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Satb1 Regulates Contactin 5 to Pattern Dendrites of a Mammalian Retinal Ganglion Cell.
Specimen part
View SamplesThe development of the epidermis, a stratified squamous epithelium, is dependent on the regulated differentiation of keratinocytes. Differentiation begins with the initiation of stratification, a process tightly controlled through proper gene expression. AP-2 is expressed in skin and previous research suggested a pathway where p63 gene induction results in increased expression of AP-2 which in turn is responsible for induction of K14. This study uses a conditional gene ablation model to further explore the role of AP-2 in skin development. Mice deficient for AP-2 exhibited delayed expression of p63, K14, and K1, key genes required for development and differentiation of the epidermis. In addition, microarray analysis of E16.5 skin revealed delayed expression of additional late epidermal differentiation genes: filaggrin, repetin and secreted Ly6/Plaur domain containing 1, in mutant mice. The genetic delay in skin development was further confirmed by a functional delay in the formation of an epidermal barrier. These results document an important role for AP-2 in skin development, and reveal the existence of regulatory factors that can compensate for AP-2 in its absence.
Disruption of epidermal specific gene expression and delayed skin development in AP-2 gamma mutant mice.
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View SamplesThe goal of this experiment was to define gene expression patterns of two mouse retinal ganglion cell subsets, labeled by expression of fluorescent proteins in Hb9-GFP and Drd4-GFP mice, all retinal ganglion cells labeled by anti-Thy1 antibody staining.
Satb1 Regulates Contactin 5 to Pattern Dendrites of a Mammalian Retinal Ganglion Cell.
Specimen part
View SamplesGene expression was analyzed in intestinal epithelial cells of germ-free and wildtype mice.
A novel role for constitutively expressed epithelial-derived chemokines as antibacterial peptides in the intestinal mucosa.
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