Mesenchymal-Epithelial Transition Regulates Initiation of Pluripotency Exit before Gastrulation
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PROVIDER: PRJNA471513 | ENA |
REPOSITORIES: ENA
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Project description:The pluripotent epiblast gives rise to all tissues and organs in an adult body. Its differentiation starts at gastrulation when the epiblast generates mesoderm and endoderm germ layers through a process called epithelial-mesenchymal transition (EMT). Although gastrulation EMT coincides with loss of epiblast pluripotency, pluripotent cells in development and in culture can adopt either mesenchymal or epithelial morphology. The relationship between epiblast pluripotency and epiblast morphology is not well understood. In this work, using chicken epiblast and human induced pluripotent stem cell (hiPSC) models, we show that pluripotent cells undergo an obligatory mesenchymal-epithelial transition (MET) prior to EMT-associated pluripotency loss. Epiblast MET and the subsequent EMT are two distinct processes. The former, a partial MET, is associated with reversible pluripotency exit; whereas the latter, a full EMT, is associated with complete and irreversible pluripotency loss. We provide evidence that integrin-mediated cell-matrix interaction, but not E-cadherin-mediated cell-cell interaction, is a key player in pluripotency exit regulation. We propose that epiblast partial MET is an evolutionarily conserved process among all amniotic vertebrates and its developmental function is to mediate planar symmetry-breaking within an epithelialized epiblast, taking place after epiblast MET but before gastrulation EMT.
2018-12-31 | GSE114476 | GEO
Project description:Nanog regulates Pou3f1 expression at the exit from pluripotency during gastrulation
| PRJNA577428 | ENA
Project description:Pluripotency is regulated by a network of transcription factors that maintains early embryonic cells in an undifferentiated state while allowing them to proliferate. NANOG is a critical factor for maintaining pluripotency and its role in primordial germ cell differentiation has been well described. However, Nanog is expressed during gastrulation across all the posterior epiblast, and only later in development its expression is restricted to primordial germ cells. In this work, we unveiled a previously unknown mechanism by which Nanog specifically represses genes involved in anterior epiblast lineage. Analysis of transcriptional data from both embryonic stem cells and gastrulating mouse embryos revealed Pou3f1 expression to be negatively correlated with that of Nanog during the early stages of differentiation. We have functionally demonstrated Pou3f1 to be a direct target of NANOG by using a dual transgene system for the controlled expression of Nanog. Use of Nanog null ES cells further demonstrated a role for Nanog in repressing a subset of anterior neural genes. Deletion of a NANOG binding site (BS) located nine kilobases downstream of the transcription start site of Pou3f1 revealed this BS to have a specific role in the regionalization of the expression of this gene in the embryo. Our results indicate an active role of Nanog inhibiting neural regulatory networks by repressing Pou3f1 at the onset of gastrulation.
2019-10-31 | GSE138818 | GEO
Project description:Pluripotency is regulated by a network of transcription factors that maintain early embryonic cells in an undifferentiated state while allowing them to proliferate. NANOG is a critical factor for maintaining pluripotency and its role in primordial germ cell differentiation has been well described. However, Nanog is expressed during gastrulation across all the posterior epiblast, and only later in development is its expression restricted to primordial germ cells. In this work, we unveiled a previously unknown mechanism by which Nanog specifically represses genes involved in anterior epiblast lineage. Analysis of transcriptional data from both embryonic stem cells and gastrulating mouse embryos revealed Pou3f1 expression to be negatively correlated with that of Nanog during the early stages of differentiation. We have functionally demonstrated Pou3f1 to be a direct target of NANOG by using a dual transgene system for the controlled expression of Nanog Use of Nanog null ES cells further demonstrated a role for Nanog in repressing a subset of anterior neural genes. Deletion of a NANOG binding site (BS) located nine kilobases downstream of the transcription start site of Pou3f1 revealed this BS to have a specific role in the regionalization of the expression of this gene in the embryo. Our results indicate an active role of Nanog inhibiting neural regulatory networks by repressing Pou3f1 at the onset of gastrulation.This article has an associated First Person interview with the joint first authors of the paper.
| S-EPMC6899006 | biostudies-literature
Project description:Gastrulation is a milestone event of embryonic development, during which germ layers are specified and reassigned into the body plan. Due to the inaccessibility in vivo at this stage and the ethical limitations, gastrulation currently remains a mystery in primates. Here, we report the establishment of an in vitro system to culture cynomolgus monkey embryos after up to 20 days to develop beyond the initiation of gastrulation. The histology, immunostaining and single cell sequencing results showed that the in vitro cultured embryos largely recapitulated the key events of early post-implantation development, and initiated gastrulation in primates. Considering the high similarities between monkeys and humans, this system will provide a unique platform for the investigations of human early post-implantation development at physiological, pathological and environmental conditions.
2019-11-01 | GSE130114 | GEO
Project description:Some features underlying replication origin activation in metazoan cells have been identified, but little is known about their regulation during metazoan development. Using the nascent strand purification method, we identified replication origins throughout Caenorhabditis elegans embryonic development and found that the origin repertoire is thoroughly reorganized after gastrulation onset. During the pluripotent embryonic stages (pre-gastrula), potential cruciform structures and open chromatin are determinant factors to establish replication origins. The enrichment of replication origins in transcription factor binding sites and their presence inside promoters of highly transcribed genes, particularly operons, argue that transcriptional activity contributes to replication initiation before gastrulation. After the gastrula transition, when differentiation programs are set in the embryos, origins are particularly selected at enhancers, in the vicinity of CGI-like sequences, and non-coding genes. Our findings suggest that origin selection coordinates replication initiation with transcriptional programs during metazoan development.
2017-01-22 | GSE86651 | GEO
Project description:Tracing early mammalian lineage decisions by single cell genomics. Lewis Wolpert famously called gastrulation the most important time in your life. During this fascinating process, a pluripotent stem cell population in the early embryo gives rise to the three germ layers from which all organ systems develop. Cell signalling and transcriptional networks are known to regulate aspects of gastrulation, but the precise mechanisms have not been investigated at the single cell level. Thus, new principles remain to be discovered that govern the exit from naïve pluripotency, epigenetic priming, stochasticity in transcriptional programmes, symmetry breaking, and acquisition of heritable transcriptome patterns. We have brought together a consortium of experts in single cell genomics, mammalian postimplantation development, and computational biology to comprehensively tackle this challenge. We will apply recently established single cell genomics techniques for DNA, RNA, and DNA methylation to profile the majority of the cells in mouse postimplantation embryos. This will result in epigenetic and gene expression maps of most cells together with experimentally determined lineage relationships, hence populating a Waddingtonian landscape. Based on such maps, combinations of transcription factors and epigenetic modifiers will be used to experimentally direct differentiation in human iPS cells.
2016-07-08 | E-MTAB-4026 | biostudies-arrayexpress
Project description:Naïve T cells respond to antigen stimulation by exiting from quiescence into clonal expansion and functional differentiation, but the control mechanism is elusive. Here we describe that Raptor/mTORC1-dependent metabolic reprogramming is a central determinant of this transitional process. Loss of Raptor abrogates T cell priming and Th2 cell differentiation, although Raptor function is less important for continuous proliferation of actively cycling cells. mTORC1 coordinates multiple metabolic programs in T cells including glycolysis, lipid synthesis and oxidative phosphorylation to mediate antigen-triggered exit from quiescence. mTORC1 further links glucose metabolism to the initiation of Th2 differentiation by orchestrating cytokine receptor expression and cytokine responsiveness. Activation of Raptor/mTORC1 integrates T cell receptor (TCR) and CD28 co-stimulatory signals in antigen-stimulated T cells. Our studies identify a Raptor/mTORC1-dependent pathway linking signal-dependent metabolic reprogramming to quiescence exit, and this in turn coordinates lymphocyte activation and fate decisions in adaptive immunity. We used microarrays to explore the gene expression profiles differentially expressed in CD4+ T-cells from wild-type (WT) and CD4(cre) x Raptor(fl/fl) mice before and after stimulation with anti CD3/CD28 antibodies.
2014-01-27 | E-GEOD-51668 | biostudies-arrayexpress
Project description:The journey of a newly synthesized polypeptide starts in the peptidyltransferase center of the ribosome, from where it traverses the exit tunnel. The interior of the ribosome exit tunnel is neither straight nor smooth. How the ribosome dynamics in vivo is influenced by the exit tunnel is poorly understood. Genome-wide ribosome profiling in mammalian cells reveals elevated ribosome density at the start codon and surprisingly the downstream 5th codon position as well. We found that the highly focused ribosomal pausing shortly after initiation is attributed to the geometry of the exit tunnel, as deletion of the loop region from ribosome protein L4 diminishes translational pausing at the 5th codon position. Unexpectedly, the ribosome variant undergoes translational abandonment shortly after initiation, suggesting that there exists an obligatory step between initiation and elongation commitment. We propose that the post-initiation pausing of ribosomes represents an inherent signature of the translation machinery to ensure productive translation.
2021-02-17 | GSE166874 | GEO
Project description:Embryonic stem cells (ESC) are able to give rise to any somatic cell type. A lot is known about how ESC pluripotency is maintained, but comparatively less is known about how differentiation is promoted. Cell fate decisions are regulated by interactions between signalling and transcriptional networks. Recent studies have shown that the overexpression or downregulation of the transcription factor Jun can affect the ESC fate. Here we have focussed on the role of the Jun in the exit of mouse ESCs from ground state pluripotency and the onset of early differentiation. Transcriptomic analysis of differentiating ESCs reveals that Jun is required to upregulate a programme of genes associated with cell adhesion as ESCs exit the pluripotent ground state.
2015-12-07 | E-MTAB-4068 | biostudies-arrayexpress