Histone modifications mediate transcription factor regulation and contribute to neuronal subtype identity
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE218312 | GEO | 2023/11/18
REPOSITORIES: GEO
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Project description:Histone modifications mediate transcription factor regulation and contribute to neuronal subtype identity
| PRJNA903145 | ENA
Project description:During development, specialized cell lineages are generated through the establishment of cell type-specific transcriptional patterns and epigenetic programs. However, the precise mechanisms and regulators that maintain these specialized cell states remain largely elusive. To identify molecules that safeguard somatic cell identity, we performed two comprehensive RNAi screens targeting known and predicted chromatin regulators during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation, DNA methylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiencies by several orders of magnitude and generated iPSCs two to three times faster compared to controls without affecting cell proliferation. We demonstrate that suppression of CAF-1 leads to a more accessible chromatin structure specifically at enhancer elements early during reprogramming. These changes were accompanied by increased binding of the reprogramming factor Sox2 to ESC-specific regulatory elements and earlier activation of pluripotency-associated genes. Notably, suppression of CAF-1 also enhanced iPSC formation from blood progenitors as well as the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as an unanticipated regulator of somatic cell identity and provide a potential strategy to modulate cellular plasticity in a regenerative setting. Keywords: Genome binding/occupancy profiling by high throughput sequencing Chromatin accessibility and Sox2 bindings in CAF-1 knockdown and Renilla control during early OKSM reprogramming by high throughput sequencing
2015-12-10 | E-GEOD-72744 | biostudies-arrayexpress
Project description:Human bone marrow stromal cells (BMSCs) are key elements of the hematopoietic environment and they play a central role in bone and bone marrow physiology. However, how key BMSC functions are regulated is largely unknown. We analyzed the role of the immediate early response transcription factor EGR1 as key BMSC regulator and found that EGR1 was highly expressed in prospectively-isolated primary BMSCs, downregulated upon culture, and lower in non-CFU-F-containing CD45neg BM cells. Furthermore, EGR1 expression was lower in proliferative regenerating adult and fetal primary cells compared to adult steady-state BMSCs. Accordingly, EGR1 overexpression markedly decreased BMSC proliferation but considerably improved hematopoietic stroma support function as indicated by an increased production of transplantable CD34+CD90+ hematopoietic stem cells in expansion co-cultures. The improvement of BMSC stroma support function was mediated by increased expression of hematopoietic supporting genes, such as VCAM1 and CCL28. On the other hand, EGR1 knockdown increased ROS-mediated BMSC proliferation, and clearly reduced BMSC hematopoietic stroma support potential. These findings thus show that EGR1 is a key BMSC transcription factor with a dual role in regulating proliferation and hematopoietic stroma support function that is controlling a genetic program to coordinate the specific functions of BMSC in their different biological contexts.
2019-06-27 | PXD011767 | Pride
Project description:To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify first order phosphorylation targets of DNA-PKcs. Results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at S301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response by modulating expression of cytokines and key costimulatory molecules. Mutation of serine 301 to alanine via CRISPR-Cas9 resulted in increased proteasomal degradation of Egr1 and a decrease in Egr1-dependent transcription of IL2 (interleukin-2) in activated T cells. Our findings identify DNA-PKcs as a critical intermediary link between T cell activation and T cell fate and a novel phosphosite involved in regulating Egr1 activity.
2021-12-21 | PXD026352 | Pride
Project description:We performed ChIP-seq to analyze chromatin bindings of IRF4 transcription factor in cDC2.
2021-05-07 | GSE174011 | GEO
Project description:Cortical interneurons originating in the embryonic medial ganglionic eminence (MGE) diverge into a range of different subtypes found in the adult mouse cerebral cortex. The mechanisms underlying this divergence and the timing when subtype identity is set up remain unclear. We identify the highly conserved transcriptional co-factor MTG8 as being pivotal in the development of a large subset of MGE cortical interneurons that co-expresses Somatostatin (SST) and Neuropeptide Y (NPY). MTG8 interacts with the pan-MGE transcription factor LHX6 and together the two factors are sufficient to promote expression of critical cortical interneuron subtype identity genes. The SST-NPY cortical interneuron fate is initiated early, well before interneurons migrate into the cortex, demonstrating an early onset specification program. Our findings suggest that transcriptional co-factors and modifiers of generic lineage specification programs may hold the key to the emergence of cortical interneuron heterogeneity from the embryonic telencephalic germinal zones.
| S-EPMC9445035 | biostudies-literature
Project description:BackgroundThe thalamus is often defined as the 'gateway to consciousness', a feature that is supported by the specific connectivity and electrophysiological properties of its neurons. Inhibitory GABAergic neurons are required for the dynamic gating of information passing through the thalamus. The high degree of heterogeneity among thalamic GABA neurons suggests that, during embryonic development, alternative differentiation programmes exist to guide the acquisition of inhibitory neuron subtype identity.ResultsTaking advantage of the accessibility of the developing chick embryo, we have used in ovo manipulations of gene expression to test the role of candidate transcription factors in controlling GABAergic neuronal subtype identity in the developing thalamus.ConclusionsIn this study, we describe two alternative differentiation programmes for GABAergic neurogenesis in the thalamus and identify Helt and Dlx2 as key transcription factors that are sufficient to direct neuronal progenitors along a specific differentiation pathway at the expense of alternative lineage choices. Furthermore, we identify Calb2, a gene encoding for the GABA subtype marker calretinin as a target of the transcription factor Sox14. This work is a step forward in our understanding of how GABA neuron diversity in the thalamus is achieved during development and will help future investigation of the molecular mechanisms that lead up to the acquisition of different synaptic targets and electrophysiological features of mature thalamic inhibitory neurons.
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Project description:Tau aggregation into insoluble filaments is the defining pathological hallmark of tauopathies. However, it is not known what controls the formation and templated seeding of strain-specific structures associated with individual tauopathies. Here, we use cryo-electron microscopy (cryo-EM) to determine the structures of tau filaments from corticobasal degeneration (CBD) human brain tissue. Cryo-EM and mass spectrometry of tau filaments from CBD reveal that this conformer is heavily decorated with posttranslational modifications (PTMs), enabling us to map PTMs directly onto the structures. By comparing the structures and PTMs of tau filaments from CBD and Alzheimer's disease, it is found that ubiquitination of tau can mediate inter-protofilament interfaces. We propose a structure-based model in which cross-talk between PTMs influences tau filament structure, contributing to the structural diversity of tauopathy strains. Our approach establishes a framework for further elucidating the relationship between the structures of polymorphic fibrils, including their PTMs, and neurodegenerative disease.
| S-EPMC7491959 | biostudies-literature
Project description:The functions of EGR1, a multifunctional transcription factor, in prostate cancer are well documented. However, little is known about the functions of EGR1 in lung cancer. we observed the function of EGR1 in non-small cell lung carcinoma (NSCLC) and identified the genes that influence cell fate and tumor development. We used microarrays to detail the global programme of gene expression and identified genes differentially expressed when EGR1-overexpressed. We have demonstrated that EGR1 is able to increase cell apoptosis, and inhibit metastasis. And we sought to find genes distributed to decrease the malignancy of human non-small cell lung cancer regulated by EGR1. To that end, H1299 cells were transfected either EGR1 or pcDNA3.1. After 48h, cells were collected for RNA extraction and hybridization on Affymetrix microarrays (PEGR1 VS PCDNA3.1).
2013-09-17 | E-GEOD-50913 | biostudies-arrayexpress
Project description:During cardiogenesis, most myocytes arise from cardiac progenitors expressing the transcription factors Isl1 and Nkx2-5. Here, we show that a direct repression of Isl1 by Nkx2-5 is necessary for proper development of the ventricular myocardial lineage. Overexpression of Nkx2-5 in mouse embryonic stem cells (ESCs) delayed specification of cardiac progenitors and inhibited expression of Isl1 and its downstream targets in Isl1(+) precursors. Embryos deficient for Nkx2-5 in the Isl1(+) lineage failed to downregulate Isl1 protein in cardiomyocytes of the heart tube. We demonstrated that Nkx2-5 directly binds to an Isl1 enhancer and represses Isl1 transcriptional activity. Furthermore, we showed that overexpression of Isl1 does not prevent cardiac differentiation of ESCs and in Xenopus laevis embryos. Instead, it leads to enhanced specification of cardiac progenitors, earlier cardiac differentiation, and increased cardiomyocyte number. Functional and molecular characterization of Isl1-overexpressing cardiomyocytes revealed higher beating frequencies in both ESC-derived contracting areas and Xenopus Isl1-gain-of-function hearts, which associated with upregulation of nodal-specific genes and downregulation of transcripts of working myocardium. Immunocytochemistry of cardiomyocyte lineage-specific markers demonstrated a reduction of ventricular cells and an increase of cells expressing the pacemaker channel Hcn4. Finally, optical action potential imaging of single cardiomyocytes combined with pharmacological approaches proved that Isl1 overexpression in ESCs resulted in normally electrophysiologically functional cells, highly enriched in the nodal subtype at the expense of the ventricular lineage. Our findings provide an Isl1/Nkx2-5-mediated mechanism that coordinately regulates the specification of cardiac progenitors toward the different myocardial lineages and ensures proper acquisition of myocyte subtype identity.
| S-EPMC6750130 | biostudies-literature