Project description:<p>Non-coding elements in our genomes that play critical roles in complex disease are frequently marked by highly unstable RNA species. Sequencing nascent RNAs attached to an actively transcribing RNA polymerase complex can identify unstable RNAs, including those templated from gene-distal enhancers (eRNAs). However, nascent RNA sequencing techniques remain challenging to apply in some cell lines and especially to intact tissues, limiting broad applications in fields such as cancer genomics and personalized medicine. Here we report the development of chromatin run-on and sequencing (ChRO-seq), a novel run-on technology that maps the location of RNA polymerase using virtually any frozen tissue sample, including samples with degraded RNA that are intractable to conventional RNA-seq. We used ChRO-seq to develop the first maps of nascent transcription in 23 human glioblastoma (GBM) brain tumors and patient derived xenografts. Remarkably, >90,000 distal enhancers discovered using the signature of eRNA biogenesis within primary GBMs closely resemble those found in the normal human brain, and diverge substantially from GBM cell models. Despite extensive overall similarity, 12% of enhancers in each GBM distinguish normal and malignant brain tissue. These enhancers drive regulatory programs similar to the developing nervous system and are enriched for transcription factor binding sites that specify a stem-like cell fate. These results demonstrate that GBMs largely retain the enhancer landscape associated with their tissue of origin, but selectively adopt regulatory programs that are responsible for driving stem-like cell properties. We also identified enhancers and their associated transcription factors that regulate genes characteristic of each known GBM subtype, and discovered a core group of transcription factors that control the expression of genes associated with clinical outcomes. This study uncovers new insights into the molecular etiology of GBM and introduces ChRO-seq which can now be used to map regulatory programs contributing to a variety of complex diseases.</p>

Project description:Chickarmane2006 - Stem cell switch reversible Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch. This model is described in the article: Transcriptional dynamics of the embryonic stem cell switch. Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C PLoS Computational Biology. 2006; 2(9):e123 Abstract: Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG. This model is hosted on BioModels Database and identified by: MODEL7957907314 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:Chickarmane2006 - Stem cell switch irreversible Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch. This model is described in the article: Transcriptional dynamics of the embryonic stem cell switch. Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C PLoS Computational Biology. 2006; 2(9):e123 Abstract: Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG. This model is hosted on BioModels Database and identified by: MODEL7957942740 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:Cell fate transitions involve integration of genomic information encoded by regulatory elements, such as enhancers, with the cellular environment. However, identification of the genomic sequences that control the earliest steps of human embryonic development represents a formidable challenge. Here we show that in human embryonic stem cells (hESCs) unique chromatin signatures identify two distinct classes of genomic elements, both of which are marked by the presence of chromatin regulators p300 and BRG1, and monomethylation of histone H3 at lysine 4 (H3K4me1). In addition, the elements of the first class are distinguished by the acetylation of histone H3 at lysine 27 (H3K27ac), overlap with previously characterized enhancers active in hESCs, and are generally located proximally to genes expressed in hESCs and in the epiblast. In contrast, the elements within the second class, which we termed M-bM-^@M-^\poised enhancersM-bM-^@M-^], are distinguished by the absence of H3K27ac, enrichment of histone H3 lysine 27 trimethylation (H3K27me3) and are linked to genes inactive in hESCs and involved in orchestrating early steps in mammalian development, such as gastrulation, mesoderm formation and neurulation. Consistent with the poised identity, during differentiation of hESCs to neuroepithelium, a neuroectoderm-specific subset of these elements acquires a chromatin signature associated with active enhancers. Remarkably, when assayed in zebrafish embryos, human poised enhancer elements are able to direct cell type and stage specific expression patterns characteristic of their proximal developmental gene, even in the absence of sequence conservation in the fish genome. Our data demonstrate that enhancers are epigenetically pre-marked and suggest a heretofore unappreciated role of H3K27me3 at distal regulatory elements. Moreover, the unique chromatin signature associated with poised enhancers allowed us to uncover over 2,000 putative developmental regulatory sequences, thereby creating an invaluable resource for future studies and isolation of transient, rare cell populations representing early steps of human development. For GSM602289-90: RNA-seq experiments in human ESC and neuroectodermal (NEC) speheres For GSM602291-303: Genome-wide analysis of p300, H3K4me3, H3K4me1, H3K27me3 and H3K27ac in human embryonic stem cells (ESC) and neuroectoderm cells (NEC). Additionally, in H9 ESC ChIP-seq were alsoe obtained for BRG1 and FAIRE-seq was also performed.

			Action	DRS
	SRR1030510.fastq.gz	Fastqsanger.gz
	SRR1030503.fastq.gz	Fastqsanger.gz
	SRR1030504.fastq.gz	Fastqsanger.gz
	SRR1030505.fastq.gz	Fastqsanger.gz
	SRR1030506.fastq.gz	Fastqsanger.gz

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Homo sapiens

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