Gain of chromatin loops marks the exit from naive pluripotency - ChIP seq for CTCF and Rad21
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ABSTRACT: ChIP-seq to map the binding sites for CTCF and cohesin subunit Rad21 in the naive mES cells (46C cell line grown in the 2i/LIF condition) and in the neural stem cells (derived from the 46C ES cells using the mono-layer differentiation protocol, grown in the N2B27 medium these cells are Nestin+). The naive mES cells were grown in two different media (fetal bovine serum, FBS and 2i/LIF culture - naive pluripotency conditions) as detailed in the growth protocols.
Project description:RNA-binding proteins (RBPs) have essential roles in RNA-mediated gene regulation, and yet annotation of RBPs is limited mainly to those with known RNA-binding domains. To systematically identify the RBPs of embryonic stem cells (ESCs), we here employ interactome capture, which combines UV cross-linking of RBP to RNA in living cells, oligo(dT) capture and MS. From mouse ESCs (mESCs), we have defined 555 proteins constituting the mESC mRNA interactome, including 283 proteins not previously annotated as RBPs. Of these, 68 new RBP candidates are highly expressed in ESCs compared to differentiated cells, implicating a role in stem-cell physiology. Two well-known E3 ubiquitin ligases, Trim25 (also called Efp) and Trim71 (also called Lin41), are validated as RBPs, revealing a potential link between RNA biology and protein-modification pathways. Our study confirms and expands the atlas of RBPs, providing a useful resource for the study of the RNA-RBP network in stem cells.
Project description:Embryonic stem cell (ESC) fate decisions are regulated by a complex molecular circuitry that requires tight and coordinated gene expression regulations at multiple levels from chromatin organization to mRNA processing. Recently, ribosome biogenesis and translation have emerged as key pathways that efficiently control stem cell homeostasis. However, the molecular mechanisms underlying the regulation of these pathways remain largely unknown to date. Here, we analyzed the expression, in mouse ESCs, of over 300 genes involved in ribosome biogenesis and we identified RSL24D1 as the most differentially expressed between self-renewing and differentiated ESCs. RSL24D1 is highly expressed in multiple mouse pluripotent stem cell models and its expression profile is conserved in human ESCs. RSL24D1 is associated with nuclear pre-ribosomes and is required for the maturation and the synthesis of 60S subunits in mouse ESCs. Interestingly, RSL24D1 depletion significantly impairs global translation, particularly of key pluripotency factors, including POU5F1 and NANOG, as well as components of the polycomb repressive complex 2 (PRC2). Consistently, RSL24D1 is required for mouse ESC self-renewal and proliferation. Taken together, we show that RSL24D1-dependant ribosome biogenesis is required to both sustain the expression of pluripotent transcriptional programs and silence developmental programs, which concertedly dictate ESC homeostasis.
Project description:Regulation of gene expression underlies the establishment and maintenance of cell identity. Chromatin structure and gene activity are linked at long-range via positioning of loci to transcriptionally permissive (euchromatin) or repressive (heterochromatin) environments and at short-range by connecting cis regulatory elements such as promoters and enhancers. However, the dynamics of these processes during cell differentiation still remains unclear. We used Tethered Chromatin Conformation Capture (TCC) to compare the three dimensional chromatin structure of mouse embryonic stem cells (ESC) and neural stem cells (NSC) which we directly derived from the ESC.
Project description:Recently, RNA sequencing has achieved single cell resolution, but what is limiting is an effective way to routinely isolate and process large numbers of individual cells for in-depth sequencing, and to do so quantitatively. We have developed a droplet-microfluidic approach for parallel barcoding thousands of individual cells for subsequent RNA profiling by next-generation sequencing. This high-throughput method shows a surprisingly low noise profile and is readily adaptable to other sequencing-based assays. Using this technique, we analyzed mouse embryonic stem cells, revealing in detail the population structure and the heterogeneous onset of differentiation after LIF withdrawal. The reproducibility and low noise of this high-throughput single cell data allowed us to deconstruct cell populations and infer gene expression relationships. A total of 8 single cell data sets are submitted: 3 for mouse embryonic stem (ES) cells (1 biological replicate, 2 technical replicates); 3 samples following LIF withdrawal (days 2,4, 7); one pure RNA data set (from human lymphoblast K562 cells); and one sample of single K562 cells.
Project description:Altered metabolism is a hallmark of cancer, but little is still known about its regulation. Here we measure transcriptomic, proteomic, phospho-proteomic and fluxomics data in a breast cancer cell-line across three different conditions. Integrating these multiomics data within a genome scale human metabolic model in combination with machine learning we systematically chart the different layers of metabolic regulation in breast cancer, predicting which enzymes and pathways are regulated at which level. We distinguish between two types of reactions, directly or indirectly regulated. Directly-regulated reactions include those whose flux is regulated by transcriptomic alterations (~890) or via proteomic or phospho-proteomics alterations (~140) in the enzymes catalyzing them. Indirectly regulated reactions are those that currently lack evidence for direct regulation in our measurements or predictions (~930). Remarkably, we find that the flux of indirectly regulated reactions is strongly coupled to the flux of the directly regulated ones, uncovering a hierarchical organization of breast cancer metabolism. Furthermore, the predicted indirectly regulated reactions are predominantly bi-directional. Taken together, this architecture may facilitate the formation of stochiometrically consistent flux distributions in response to the varying environmental conditions incurred by the tumor cells. The approach presented lays a conceptual and computational basis for a more complete mapping of metabolic regulation in different cancers with incoming additional data.
Project description:Regulation of gene expression underlies the establishment and maintenance of cell identity. Chromatin structure and gene activity are linked at long-range via positioning of loci to transcriptionally permissive (euchromatin) or repressive (heterochromatin) environments and at short-range by connecting cis regulatory elements such as promoters and enhancers. However, the dynamics of these processes during cell differentiation still remains unclear. We used Tethered Chromatin Conformation Capture (TCC) to compare the three dimensional chromatin structure of mouse embryonic stem cells (ESC) and neural stem cells (NSC) which we directly derived from the ESC.
Project description:Over the past years, microRNAs (miRNAs) have emerged as crucial factors that regulate self-renewal and differentiation of embryonic stem cells (ESCs). Although much is known about their role in maintaining ESC pluripotency, the mechanisms by which they affect cell fate decisions remain poorly understood. By performing deep sequencing to profile miRNAs expression in mouse ESCs (mESCs) and differentiated embryoid bodies (EBs), we identified four differentially expressed miRNAs. Among them, miR-191 and miR-16-1 are highly expressed in ESCs and repress Smad2, the most essential mediator of Activin-Nodal signaling, resulting in the inhibition of mesendoderm formation. miR-23a, which is also downregulated in the differentiated state, suppresses differentiation towards the endoderm and ectoderm lineages. We further identified miR-421 as a differentiation-associated regulator through the direct repression of core pluripotency transcription factor Oct4 and BMP-signaling components, Smad5 and Id2. Collectively, our findings uncover a regulatory network between the studied miRNAs and both branches of TGF-β/BMP signaling pathways revealing their importance for ESC lineage decisions. miRNA profiles of ESCs and differentiated EBs D8 were generated by deep sequencing, in duplicate, using ION TORRENT PGM platform
Project description:This SuperSeries is composed of the following subset Series: GSE14559: Timed induction of 50 transcription factors in ES cells reveals a common mechanism to initiate differentiations GSE14586: Cdx2 Binding Sites On Cdx2 Expressing ES Cells GSE16148: Timed induction of 10 transcription factors - ES time series data Refer to individual Series
Project description:Mast cells (MCs) are important cellular components of the tumor microenvironment and are significantly associated with poor patient outcomes in prostate cancer and other solid cancers. The promotion of tumor progression partly involves heterotypic interactions between MCs and cancer-associated fibroblasts (CAFs) which combine to potentiate a pro-tumor extracellular matrix and promote epithelial cell invasion and migration. Thus far, the interactions between MCs and CAFs remains poorly understood. To identify molecular changes that may alter resident MC function in the prostate tumor microenvironment, we profiled the transcriptome of human prostate MCs, isolated from patient-matched non-tumor and tumor-associated regions of fresh radical prostatectomy tissue. Transcriptomic profiling revealed a distinct gene expression profile of MCs isolated from prostate tumor regions, including the downregulation of SAMD14, a putative tumor suppressor gene. Proteomic profiling revealed overexpression of SAMD14 in HMC-1 MCs altered the secretion of proteins associated with immune regulation and extracellular matrix processes. To assess MC biological function within a model of the prostate tumor microenvironment, HMC-1-SAMD14+ conditioned media was added to co-cultures of primary prostatic CAFs and prostate epithelium. HMC-1-SAMD14+ secretions were shown to reduce the deposition and alignment of matrix produced by CAFs and suppress pro-tumorigenic prostate epithelial morphology. Overall, our data presents the first profile of human MCs derived from patient prostate cancer specimens and identifies MC-derived SAMD14 as an important mediator of MC phenotype and function within the prostate tumor microenvironment.