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: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
Project description:Polycomb group (PcG) proteins are highly conserved epigenetic transcriptional repressors important for the control of numerous developmental gene expression programs and have recently been implicated in the modulation of embryonic stem cell (ESC) identity. We identified the PcG protein PCL2 (polycomb-like 2) in a genome-wide screen for novel regulators of self-renewal and pluripotency and predicted that it would play an important role in mouse ESC fate determination. Using multiple biochemical strategies, we provide evidence that PCL2 is a novel Polycomb Repressive Complex 2 (PRC2)-associated protein in mouse ESCs. Knockdown of Pcl2 in ESCs resulted in heightened self-renewal characteristics, defects in differentiation and altered patterns of histone methylation. Through integration of global gene expression and promoter occupancy analyses of both PCL2 and PRC2 components EZH2 and SUZ12, we have predicted PCL2 target genes and formulated regulatory networks describing the role of PCL2 both in modulating transcription of ESC self-renewal genes in undifferentiated ESCs as well as developmental regulators during early commitment and differentiation. Cells were stably expressing Pcl2 shRNA or shRNA mismatch control sequences. Hybridizations of three biological replicates for both the control and Pcl2 shRNA clone were performed.
Project description:Stem cell fate is governed by the integration of intrinsic and extrinsic positive and negative signals upon inherent transcriptional networks. To identify novel embryonic stem cell (ESC) regulators and assemble transcriptional networks controlling ESC fate, we performed temporal expression microarray analyses of ESCs following the initiation of commitment and integrated these data with known genome-wide transcription factor binding. Effects of forced under- or over-expression of predicted novel regulators, defined as differentially expressed genes with potential binding sites for known regulators of pluripotency, demonstrated greater than 90% correspondence with predicted function, as assessed by functional and high content assays of self-renewal. We next assembled 43 theoretical transcriptional networks in ESCs, 82% (23 out of 28 tested) of which were supported by analysis of genome-wide expression in Oct4 knockdown cells. By using this integrative approach we have, for the first time, formulated novel networks describing gene repression of key developmental regulators in undifferentiated ESCs and successfully predicted the outcomes of genetic manipulation of these networks. Experiment Overall Design: 1, 3, and 5 days LIF differentiated ESCs, and 1 and 2 days RA differentiated ESCs
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:Polycomb group (PcG) proteins are highly conserved epigenetic transcriptional repressors important for the control of numerous developmental gene expression programs and have recently been implicated in the modulation of embryonic stem cell (ESC) identity. We identified the PcG protein PCL2 (polycomb-like 2) in a genome-wide screen for novel regulators of self-renewal and pluripotency and predicted that it would play an important role in mouse ESC fate determination. Using multiple biochemical strategies, we provide evidence that PCL2 is a novel Polycomb Repressive Complex 2 (PRC2)-associated protein in mouse ESCs. Knockdown of Pcl2 in ESCs resulted in heightened self-renewal characteristics, defects in differentiation and altered patterns of histone methylation. Through integration of global gene expression and promoter occupancy analyses of both PCL2 and PRC2 components EZH2 and SUZ12, we have predicted PCL2 target genes and formulated regulatory networks describing the role of PCL2 both in modulating transcription of ESC self-renewal genes in undifferentiated ESCs as well as developmental regulators during early commitment and differentiation.
Project description:Stem cell fate is governed by the integration of intrinsic and extrinsic positive and negative signals upon inherent transcriptional networks. To identify novel embryonic stem cell (ESC) regulators and assemble transcriptional networks controlling ESC fate, we performed temporal expression microarray analyses of ESCs following the initiation of commitment and integrated these data with known genome-wide transcription factor binding. Effects of forced under- or over-expression of predicted novel regulators, defined as differentially expressed genes with potential binding sites for known regulators of pluripotency, demonstrated greater than 90% correspondence with predicted function, as assessed by functional and high content assays of self-renewal. We next assembled 43 theoretical transcriptional networks in ESCs, 82% (23 out of 28 tested) of which were supported by analysis of genome-wide expression in Oct4 knockdown cells. By using this integrative approach we have, for the first time, formulated novel networks describing gene repression of key developmental regulators in undifferentiated ESCs and successfully predicted the outcomes of genetic manipulation of these networks. Keywords: time course
Project description:Trophoblast stem cells (TS cells), derived from the trophectoderm (TE) of blastocysts, require transcription factors (TFs) and external signals (Fgf4, Activin/Nodal/Tgfb) for self-renewal. While many reports have focused on TF networks that regulate embryonic stem cell (ES cell) self-renewal and pluripotency, little is know about TF networks that regulate self-renewal in TS cells. To further understand transcriptional networks in TS cells we used chromatin immunopreciptiation and DNA microarray analysis (ChIP-chip) to investigate targets of TFs Ap-2g (Tcfap2c), Eomes, Ets2, and Gata3, and a chromatin remodeling factor, Brg1 (Smarca4). We then evaluated the transcriptional states of target genes using transcriptome analysis and genome-wide analysis of histone H3 acetylation (AcH3). Our results describe previously unknown transcriptional networks in TS cells, including TF occupancy of genes involved in ES cell self-renewal and pluripotency, co-occupancy of multiple TFs at target genes, and transcriptional regulatory circuitry within the 5 factors. Through genome-wide mapping and global expression analysis of 5 TF target genes, our data provide a comprehensive analysis of transcriptional networks that regulate TS cell self-renewal.
Project description:Many transcriptional and epigenetic networks must be integrated to maintain self-renewal and pluripotency in embryonic stem cells (ESCs) and to enable induced pluripotent stem cell (iPSC) reprogramming. Here, we explore the role of Zfp217 as a key transcriptional factor in maintaining ES cell self-renewal by permorming genome-wide ChIP-Seq analyses.