Reintroduction of CEBPA in MN1-overexpressing hematopoietic cells prevents their hyper-proliferation and restores myeloid differentiation. Forced expression of MN1 in primitive mouse hematopoietic cells causes acute myeloid leukemia and impairs all-trans retinoic acid (ATRA) induced granulocytic differentiation. Here, we studied the effects of MN1 on myeloid differentiation and proliferation using primary human CD34+ hematopoietic cells, lineage depleted mouse bone marrow cells, and bipotential (granulocytic/monocytic) human AML-cell lines. We show that exogenous MN1 stimulated the growth of CD34+ cells, which was accompanied by enhanced survival and increased cell cycle traverse in cultures supporting progenitor cell growth. Forced MN1 expression impaired both granulocytic and monocytic differentiation in vitro in primary hematopoietic cells and AML cell lines. Endogenous MN1 expression was higher in human CD34+ cells compared to both primary and in vitro differentiated monocytes and granulocytes. Microarray and real time RT-PCR analysis of MN1-overexpressing CD34+ cells showed down regulation of CEBPA and its downstream target genes. Re-introduction of conditional and constitutive CEBPA overcame the effects of MN1 on myeloid differentiation and inhibited MN1-induced proliferation in vitro. These results indicate that down regulation of CEBPA activity contributes to MN1-modulated proliferation and impaired myeloid differentiation of hematopoietic cells
Reintroduction of CEBPA in MN1-overexpressing hematopoietic cells prevents their hyperproliferation and restores myeloid differentiation.
Specimen part
View SamplesMice lacking the zinc finger transcription factor Specificity protein 3 (Sp3) die prenatally in the C57Bl/6 background. To elucidate the cause of mortality we analyzed the potential role of Sp3 in embryonic heart development. Sp3 null hearts display defective looping at E10.5, and at E14.5 the Sp3 null mutants have developed a range of severe cardiac malformations. In an attempt to position Sp3 in the cardiac developmental hierarchy, we analysed the expression patterns of >15 marker genes in Sp3 null hearts. Expression of Cardiac ankyrin repeat protein (Carp) was downregulated prematurely after E12.5, while expression of the other marker genes was not affected. ChIP analysis revealed that Sp3 is bound to the Carp promoter region in vivo. Microarray analysis indicates that small molecule metabolism and cell-cell interactions are the most significantly affected biological processes in E12.5 Sp3 null myocardium. Since the epicardium showed distension from the myocardium, we studied expression of Wt1, a marker for epicardial cells. Wt1 expression was diminished in epicardium-derived cells in the myocardium of Sp3 null hearts. We conclude that Sp3 is required for normal cardiac development, and suggest that it has a crucial role in myocardial differentiation. (
Transcription factor Sp3 knockout mice display serious cardiac malformations.
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Snail regulates MyoD binding-site occupancy to direct enhancer switching and differentiation-specific transcription in myogenesis.
Specimen part, Disease, Time
View SamplesIn skeletal myogenesis, the transcription factor MyoD activates distinct transcriptional programs in progenitors compared to terminally differentiated cells. Using ChIP-seq and gene expression analyses, we show that in primary myoblasts, Snail-HDAC1/2 repressive complex bind and exclude MyoD from its targets. Notably, Snail binds E-box motifs that are G/C-rich in their central dinucleotides, and such sites are almost exclusively associated with genes expressed during differentiation. By contrast, Snail does not bind the A/T-rich E-boxes associated with MyoD targets in myoblasts. Thus, Snai1-HDAC1/2 prevents MyoD occupancy on differentiation-specific regulatory elements and the change from Snail- to MyoD-binding often results in enhancer switching during differentiation. Furthermore, we show that a regulatory network involving Myogenic Regulatory Factors (MRFs), Snail/2, miR-30a and miR-206 acts as a molecular switch that controls entry into myogenic differentiation. Together, these results reveal a regulatory paradigm that directs distinct gene expression programs in progenitors versus terminally differentiated cells.
Snail regulates MyoD binding-site occupancy to direct enhancer switching and differentiation-specific transcription in myogenesis.
Specimen part, Time
View SamplesAlterations in the expression of key transcription factors can be harmful for pancreatic beta cell homeostasis and could lead to diabetes. This study uncovered that Prox1 overexpression obstructs beta cell maturation and results in severe hyperglycemia.
Lack of Prox1 Downregulation Disrupts the Expansion and Maturation of Postnatal Murine β-Cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide analysis shows that Ldb1 controls essential hematopoietic genes/pathways in mouse early development and reveals novel players in hematopoiesis.
Specimen part
View SamplesThe first site exhibiting hematopoietic activity in mammalian development is the yolk sac blood island, which originates from the hemangioblast. Here we performed differentiation assays, as well as genome-wide molecular and functional studies in BL-CFCs to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. We show that the previously reported lack of yolk sac hematopoiesis and vascular development in Ldb1-/- mouse result from a decreased number of hemangioblasts and a block in their ability to differentiate into erythroid and endothelial progenitor cells. Transcriptome analysis and correlation with the genome wide binding pattern of Ldb1 in hemangioblasts revealed a number of direct target genes and pathways misregulated in the absence of Ldb1. The regulation of essential developmental factors by Ldb1 defines it as an upstream transcriptional regulator of hematopoietic/endothelial development. We show the complex interplay that exists between transcription factors and signaling pathways during the very early stages of hematopoietic/endothelial development and the specific signalling occurring in hemangioblasts in contrast to more advanced hematopoietic developmental stages. Finally, by revealing novel genes and pathways, not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells.
Genome-wide analysis shows that Ldb1 controls essential hematopoietic genes/pathways in mouse early development and reveals novel players in hematopoiesis.
Specimen part
View SamplesPoised enhancers marked by H3K27me3 in pluripotent cells were previously proposed to facilitate the establishment of somatic expression programs upon embryonic stem cell (ESC) differentiation. However, the functional relevance and mechanism of action of poised enhancers remain unknown. Here, we use genetic deletions to demonstrate that poised enhancers are necessary for the induction of major anterior neural regulators. Mechanistically, poised enhancers enable RNA Polymerase II recruitment to their cognate promoters upon differentiation. Interestingly, poised enhancers already establish physical interactions with their target genes in ESC in a Polycomb repressive complex 2 (PRC2) dependent manner. Loss of PRC2 led to neither the activation of poised enhancers nor the induction of their putative target genes in undifferentiated ESC. In contrast, loss of PRC2 severely and specifically compromised the induction of major anterior neural genes representing poised enhancer targets. Overall, our work illuminates a novel function for polycomb proteins, which we propose facilitate neural induction by providing major anterior neural loci with a permissive regulatory topology. Overall design: mRNA profiles were generated by RNA-seq from mESC and AntNPC for the following lines: WT mESC, WT AntNPC, EED-/- mESC and EED-/- AntNPC
PRC2 Facilitates the Regulatory Topology Required for Poised Enhancer Function during Pluripotent Stem Cell Differentiation.
Specimen part, Treatment, Subject
View SamplesPoised enhancers marked by H3K27me3 in pluripotent cells were previously proposed to facilitate the establishment of somatic expression programs upon embryonic stem cell (ESC) differentiation. However, the functional relevance and mechanism of action of poised enhancers remain unknown. Here, we use genetic deletions to demonstrate that poised enhancers are necessary for the induction of major anterior neural regulators. Mechanistically, poised enhancers enable RNA Polymerase II recruitment to their cognate promoters upon differentiation. Interestingly, poised enhancers already establish physical interactions with their target genes in ESC in a Polycomb repressive complex 2 (PRC2) dependent manner. Loss of PRC2 led to neither the activation of poised enhancers nor the induction of their putative target genes in undifferentiated ESC. In contrast, loss of PRC2 severely and specifically compromised the induction of major anterior neural genes representing poised enhancer targets. Overall, our work illuminates a novel function for polycomb proteins, which we propose facilitate neural induction by providing major anterior neural loci with a permissive regulatory topology. Overall design: mRNA profiles were generated by RNA-seq from AntNPC derived from mESC: WT AntNPC (four biological replicates), PE Lhx5(-109)-/- Clon1 AntNPC (two biological replicates) and PE Lhx5(-109)-/- Clon2 AntNPC (two biological replicates).
PRC2 Facilitates the Regulatory Topology Required for Poised Enhancer Function during Pluripotent Stem Cell Differentiation.
Specimen part, Cell line, Treatment, Subject
View SamplesDuring B cell development the precursor B cell receptor (pre-BCR) checkpoint is thought to increase immunoglobulin k light chain (Igk) locus accessibility to the V(D)J recombinase. Accordingly, pre-B cells lacking the pre-BCR signaling molecules Btk or Slp65 showed reduced germline Vk transcription. To investigate whether pre-BCR signaling modulates Vk accessibility through enhancer-mediated Igk locus topology, we performed chromosome conformation capture and sequencing analyses. These revealed that already in pro-B cells the k enhancers robustly interact with the ~3.2 Mb Vk region and its flanking sequences. Analyses in wild-type, Btk and Slp65 single and double-deficient pre-B cells demonstrated that pre-BCR signaling reduces interactions of both enhancers with Igk locus flanking sequences and increases interactions of the 3k enhancer with Vk genes. Remarkably, pre-BCR signaling does not significantly affect interactions between the intronic enhancer and Vk genes, which are already robust in pro-B cells. Both enhancers interact most frequently with highly used Vk genes, which are often marked by transcription factor E2a. We conclude that the k enhancers interact with the Vk region already in pro-B cells and that pre-BCR signaling induces accessibility through a functional redistribution of long-range chromatin interactions within the Vk region, whereby the two enhancers play distinct roles.
Pre-B cell receptor signaling induces immunoglobulin κ locus accessibility by functional redistribution of enhancer-mediated chromatin interactions.
Specimen part
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