Wdr5 mediates self-renewal and reprogramming via the embryonic stem cell core transcriptional network (2)
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ABSTRACT: The embryonic stem (ES) cell transcriptional and epigenetic networks are critical for the maintenance of ES cell self-renewal. It remains unclear whether interactions. Here we show that a core member of the Set/MLL complex, WDrepeat protein-5 (Wdr5), is a novel regulator of self-renewal and partners with Oct4 to maintain an intact transcriptional network and for efficient formation of induced pluripotent stem (iPS) cells. Moreover, we provide evidence that Oct4 interacts with chromatin components and is indispensible for epigenetic regulation. These findings suggest an integrated transcriptional and epigenetic model, mediated through Wdr5, for the maintenance of ES cell self-renewal and somatic cell reprogramming. Differential gene expressions upon down-regulation of Wdr5 was analysed by comparing Wdr5R4 –dox (triplicate) and LucR +dox (duplicate) RNA samples Gene expression changes upon down-regulation of Oct4 was analysed by comparing Oct4 shRNA (duplicate) and GFP shRNA (duplicate) after 4day transfection Wdr5: 5 samples are analyzed: Luciferase (Luc, 2 replicates) and Wdr5 with no dox (minusDox, 3 replicates) Oct4-GFP: 4 samples are analyzed: Oct4 shRNA (Oct4, 2 replicates) and GFP shRNA (GFP, 2 replicates)
Project description:The embryonic stem (ES) cell transcriptional and epigenetic networks are critical for the maintenance of ES cell self-renewal. It remains unclear whether interactions. Here we show that a core member of the Set/MLL complex, WDrepeat protein-5 (Wdr5), is a novel regulator of self-renewal and partners with Oct4 to maintain an intact transcriptional network and for efficient formation of induced pluripotent stem (iPS) cells. Moreover, we provide evidence that Oct4 interacts with chromatin components and is indispensible for epigenetic regulation. These findings suggest an integrated transcriptional and epigenetic model, mediated through Wdr5, for the maintenance of ES cell self-renewal and somatic cell reprogramming. Differential gene expressions upon down-regulation of Wdr5 was analysed by comparing Wdr5R4 –dox (triplicate) and LucR +dox (duplicate) RNA samples Gene expression changes upon down-regulation of Oct4 was analysed by comparing Oct4 shRNA (duplicate) and GFP shRNA (duplicate) after 4day transfection
Project description:The embryonic stem (ES) cell transcriptional and epigenetic networks are critical for the maintenance of ES cell self-renewal. However, it remains unclear whether components of these networks functionally interact and if so, what factors mediate such interactions. Here we show that WD-repeat protein-5 (Wdr5), a core member of the mammalian Trithorax (trxG) complex, positively correlates with the undifferentiated state and is a novel regulator of ES cell self-renewal. We demonstrate that Wdr5, an ‘effector’ of H3K4 methylation, interacts with the pluripotency transcription factor Oct4. In concordance, genome-wide ChIP-Seq and transcriptome analyses demonstrate overlapping gene regulatory functions between Oct4 and Wdr5. We show that the Oct4-Sox2-Nanog circuitry cooperates with trxG for transcriptional activation of key self-renewal regulators. Furthermore, Wdr5 expression is required for the efficient formation of induced pluripotent stem (iPS) cells. Collectively, these findings implicate an integrated model of transcriptional and epigenetic control, mediated by select trxG members, for the maintenance of ES cell self-renewal and somatic cell reprogramming. 7 Samples
Project description:The embryonic stem (ES) cell transcriptional and epigenetic networks are critical for the maintenance of ES cell self-renewal. However, it remains unclear whether components of these networks functionally interact and if so, what factors mediate such interactions. Here we show that WD-repeat protein-5 (Wdr5), a core member of the mammalian Trithorax (trxG) complex, positively correlates with the undifferentiated state and is a novel regulator of ES cell self-renewal. We demonstrate that Wdr5, an ‘effector’ of H3K4 methylation, interacts with the pluripotency transcription factor Oct4. In concordance, genome-wide ChIP-Seq and transcriptome analyses demonstrate overlapping gene regulatory functions between Oct4 and Wdr5. We show that the Oct4-Sox2-Nanog circuitry cooperates with trxG for transcriptional activation of key self-renewal regulators. Furthermore, Wdr5 expression is required for the efficient formation of induced pluripotent stem (iPS) cells. Collectively, these findings implicate an integrated model of transcriptional and epigenetic control, mediated by select trxG members, for the maintenance of ES cell self-renewal and somatic cell reprogramming.
Project description:We present an integrated approach to identify genetic mechanisms that control self-renewal in mouse embryonic stem (ES) cells. Short hairpin RNA (shRNA) techniques are employed to down regulate a set of gene-products whose expression patterns suggest self-renewal regulatory functions. We focus on transcriptional regulators and identify seven molecules whose shRNA-mediated depletion induces differentiation, including four whose roles in self-renewal had not been demonstrated. We analyze the expression profiles of embryonic stems (ES) cells transduced with individual shRNA vectors, maintained in the presence of LIF. Experiment Overall Design: We analyze transcriptome dynamics after down-regulating each of the 8 self-renewal regulators identified in the current studies. These are Nanog, Oct4, Sox2, Esrrb, Tbx3, Tcl1, Mm.343880 and Dppa4. Gene specific shRNA transduced GFP+ cells were FACS purified daily during a seven day interval and used to interrogate Affymetrix microarrays. Empty H1P vector served as a reference.
Project description:Long intervening noncoding RNAs (lincRNAs) are prevalent genes with poorly understood functions. Here we discover a pathway of lincRNA-regulated proteolysis. The enhancer-like lincRNA HOTTIP extends the half-life of its binding protein WDR5, a subunit of the MLL H3K4 methylase complex, resulting in increased chromatin occupancy and gene activation. LincRNA-mediated stabilization requires direct RNA-protein interaction in a long RNA context, and blocks turnover at a step after target protein poly-ubiquitination. We elucidate the lincRNA binding interface on WDR5. A WDR5 mutant that selectively abrogates lincRNA binding becomes unstable, and is defective in gene activation, maintenance of histone H3 lysine 4 trimethylation, and embryonic stem cell self renewal. The ability to modulate protein turnover may allow lincRNAs to control the lifespan of molecular interactions at chromatin and elsewhere, broadening their scope in epigenetics and cell fate control. Gene expression analysis: To establish a differentiation signature for mouse V6.5 ES cells infected with anti mouse WDR5 shRNA, rescued with doxycycline inducible WDR5 WT or WDR5 F266A, total RNA was isolated in biologic duplicate from cells in different conditions and hybridized to Affymetrix Mouse 430 2.0 arrays.
Project description:We have used mouse embryonic stem cells (ESCs) as a model to study the signaling mechanisms that regulate self-renewal and commitment to differentiation. We hypothesized that genes critical to stem cell fate would be dynamically regulated at the initiation of commitment. Time course microarray analysis following initiation of commitment led us to propose a model of ESC maintenance in which highly regulated transcription factors and chromatin remodeling genes (down-regulated in our time course) maintain repression of genes responsible for cell differentiation, morphogenesis and development (up-regulated in our time course). Microarrays of Oct4, Nanog and Sox2 shRNA knockdown cell lines confirmed predicted regulation of target genes. shRNA knockdowns of candidate genes were tested in a novel high throughput screen of self-renewal, confirming their role in ESC pluripotency. We have identified genes that are critical for self-renewal and those that initiate commitment and developed draft transcriptional networks that control self-renewal and early development. Keywords: genetic modification Gene expression in Oct4 knockdown, Sox2 knockdown and their empty vector contol ES cells was analyzed.
Project description:Orphan nuclear receptor Esrrb is vital in maintaining ES cells and like Oct4, Sox2 and Nanog is essential for self-renewal and pluripotency. Esrrb functions in somatic cells via LBD/AF-2-dependent coactivator recruitment to target genes. Here we show that in ES cells coactivator recruitment is similarly required and identify Ncoa3 as the Esrrb coactivator needed for activation of its target genes. Ncoa3 is essential for self-renewal and the induction of pluripotency in reprogramming, and genome-wide analysis of Ncoa3 binding reveals extensive overlap with Esrrb and pluripotency factors along with marks of active genes. Mechanistically, we show Ncoa3 is specifically required to bridge RNApol2 to Esrrb. We thus identify a new member of the ES pluripotency network and describe Esrrb and Ncoa3 as key factors linking core pluripotency factors to the general transcription machinery. Three biological replicates each for control scrambled shRNA and Ncoa3 shRNA transfected E14 mouse ESCs. The global gene expression profiles of Ncoa3 knockdown cells were compared to control scrambled shRNA knockdown cells 4 days post-transfection.
Project description:Understanding the transcriptional regulatory circuitry responsible for pluripotency and self-renewal in embryonic stem (ES) cells is fundamental to understanding human development and realizing the therapeutic potential of these cells. The transcription factor Oct4 and the chromatin-modifying Polycomb complex, key regulators of ES cell pluripotency and self-renewal, contribute to positive and negative control of a known set of protein-coding genes. MicroRNAs (miRNAs), non-coding transcripts that participate in post-transcriptional gene regulation are also important for normal pluripotency and self-renewal in ES cells, but there has been no systematic investigation of how miRNA expression is controlled by transcriptional regulators of ES cell identity. Here we identify promoters for miRNAs in the human and mouse genomes and describe the subset of these genes that are under the control of Oct4 and Polycomb in ES cells. We find that the majority of miRNAs that are uniquely or preferentially expressed in ES cells are bound by and dependent on Oct4. Oct4 also occupies a set of miRNA genes that are co-occupied by the Polycomb Group protein, Suz12. These miRNAs, repressed in ES cells, are later expressed in differentiated cells in a highly tissue-specific fashion, suggesting that they may contribute to cell-fate determinations. These data reveal how the core transcriptional regulatory circuitry of ES cells controls the miRNA expression program that contributes to pluripotency and self-renewal.
Project description:In order to investigate the cooperative roles of Pontin and Oct4 for self-renewal and pluripotency in mouse ES cells, we performed mRNA-sequencing analysis from mRNAs isolated from Pontin- and Oct4-depleted ES cells. This analysis provides insight into molecular mechanisms for maintaining ES cell identity. mRNA expression profiles of Pontinf/f; CreER ES cells at 0, 3, or 4 days post-treatment with OHT (wild type and Pontin-depleted ES cells) and ZHBTc4 ES cells at 2 days post-treatment with tetracycline (Oct4-depleted ESE cells) were examined by Illumina Hiseq2000.
Project description:We present an integrated approach to identify genetic mechanisms that control self-renewal in mouse embryonic stem (ES) cells. Short hairpin RNA (shRNA) techniques are employed to down regulate a set of gene-products whose expression patterns suggest self-renewal regulatory functions. We focus on transcriptional regulators and identify seven molecules whose shRNA-mediated depletion induces differentiation, including four whose roles in self-renewal had not been demonstrated. We analyze the expression profiles of embryonic stems (ES) cells transduced with individual shRNA vectors, maintained in the presence of LIF. Keywords: time course