Sox17 and β-catenin co-occupy Wnt-responsive enhancers to govern the endodermal gene regulatory network
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ABSTRACT:
ORGANISM(S): Xenopus tropicalis
PROVIDER: GSE148726 | GEO | 2020/09/16
REPOSITORIES: GEO
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Project description:Lineage specification is governed by gene regulatory networks (GRNs) that integrate the activity of signaling effectors and transcription factors (TFs) on enhancers. Sox17 is a key transcriptional regulator of definitive endoderm development, and yet, its genomic targets remain largely uncharacterized. Here, using genomic approaches and epistasis experiments, we define the Sox17-governed endoderm GRN in Xenopus gastrulae. We show that Sox17 functionally interacts with the canonical Wnt pathway to specify and pattern the endoderm while repressing alternative mesectoderm fates. Sox17 and β-catenin co-occupy hundreds of key enhancers. In some cases, Sox17 and β-catenin synergistically activate transcription apparently independent of Tcfs, whereas on other enhancers, Sox17 represses β-catenin/Tcf-mediated transcription to spatially restrict gene expression domains. Our findings establish Sox17 as a tissue-specific modifier of Wnt responses and point to a novel paradigm where genomic specificity of Wnt/β-catenin transcription is determined through functional interactions between lineage-specific Sox TFs and β-catenin/Tcf transcriptional complexes. Given the ubiquitous nature of Sox TFs and Wnt signaling, this mechanism has important implications across a diverse range of developmental and disease contexts.
| S-EPMC7498262 | biostudies-literature
Project description:Sox17 and β-catenin co-occupy Wnt-responsive enhancers to govern the endodermal gene regulatory network
| PRJNA625510 | ENA
Project description:Aberrant MYC gene expression by the Wnt/beta-catenin pathway is implicated in colorectal carcinogenesis. Wnt/beta-catenin signaling stimulates association of the beta-catenin coactivator complex with two Wnt responsive enhancers (WREs) located in close proximity to MYC gene boundaries. Each enhancer directly binds members of the TCF/Lef family of transcription factors that, in turn, recruit beta-catenin. In a previous report, we showed that the downstream MYC enhancer (MYC 3' WRE) cooperated with the upstream enhancer (MYC 5' WRE) to activate expression of a heterologous reporter gene in response to Wnt/beta-catenin and mitogen signaling. Here we use chromatin conformation capture (3C) to show that the MYC 5' and 3' WREs are juxtaposed at the genomic MYC locus during active transcription. This MYC 5'3' chromatin loop is present in HCT116 human colorectal cancer cells that contain high levels of nuclear beta-catenin and is absent in HEK293 cells that contain trace amounts of nuclear beta-catenin. Depletion of functional beta-catenin/TCF complexes blocks formation of the MYC 5'3 chromatin loop. Furthermore, we find that the chromatin loop is absent in quiescent cells, but is rapidly and transiently induced by serum mitogens in a beta-catenin-dependent manner. Thus, we propose that a distinct chromatin architecture coordinated by beta-catenin/TCF-bound WREs accompanies transcriptional activation of MYC gene expression.
| S-EPMC2806753 | biostudies-literature
Project description:Inappropriate activation of c-Myc (MYC) gene expression by the Wnt/ß-catenin signaling pathway is required for colorectal carcinogenesis. The elevated MYC levels in colon cancer cells are attributed in part to ß-catenin/TCF4 transcription complexes that are assembled at proximal Wnt/ß-catenin responsive enhancers (WREs). Recent studies suggest that additional WREs that control MYC expression reside far upstream of the MYC transcription start site. Here, I report the characterization of five novel WREs that localize to a region over 400 kb upstream from MYC. These WREs harbor nucleosomes with post-translational histone modifications that demarcate enhancer and gene promoter regions. Using quantitative chromatin conformation capture, I show that the distal WREs are aligned with the MYC promoter through large chromatin loops. The chromatin loops are not restricted to colon cancer cells, but are also found in kidney epithelial and lung fibroblast cell lines that lack de-regulated Wnt signaling and nuclear ß-catenin/TCF4 complexes. While each chromatin loop is detected in quiescent cells, the positioning of three of the five distal enhancers with the MYC promoter is induced by serum mitogens. These findings suggest that the architecture of the MYC promoter is comprised of distal elements that are juxtaposed through large chromatin loops and that ß-catenin/TCF4 complexes utilize this conformation to activate MYC expression in colon cancer cells.
| S-EPMC3080403 | biostudies-literature
Project description:Rationale. The microvasculature of the central nervous system includes the blood-brain barrier (BBB), which regulates the permeability to nutrients and restricts the passage of toxic agents and inflammatory cells. Canonical Wnt/b-catenin signaling is responsible for the early phases of brain vascularization and blood-brain barrier differentiation. However, this signal declines after birth and other signaling pathways able to maintain barrier integrity at postnatal stage are still unknown. Objective. Sox17 constitutes a major downstream target of Wnt/b-catenin in endothelial cells and regulates arterial differentiation. In the present paper, we asked whether Sox17 may act downstream of Wnt/b-catenin in inducing BBB differentiation and maintenance. Methods and Results. Using reporter mice and nuclear staining of Sox17 and b-catenin, we report that while b-catenin signaling declines after birth, Sox17 activation increases and remains high in the adult. Endothelial-specific inactivation of Sox17 leads to increase of permeability of the brain microcirculation. The severity of this effect depends on the degree of BBB maturation: it is strong in the embryo, and progressively declines after birth. In search of Sox17 mechanism of action, RNA-Seq analysis of gene expression of brain endothelial cells has identified members of the Wnt/b-catenin signaling pathway as downstream targets of Sox17. Consistently, we found that Sox17 is a positive inducer of Wnt/b-catenin signaling and it acts in concert with this pathway to induce and maintain BBB properties. In vivo, inhibition of the b-catenin destruction complex or expression of a degradation-resistant b-catenin mutant, prevent the increase in permeability and retina vascular malformations observed in the absence of Sox17. Conclusions. Our data highlight a novel role for Sox17 in the induction and maintenance of the BBB and they underline the strict reciprocal tuning of this transcription factor and Wnt/b-catenin pathway. Modulation of Sox17 activity may be relevant to control BBB permeability in pathological conditions.
2019-02-12 | GSE122564 | GEO
Project description:From mice, strand-specific RNA-Seq of granulocyte-myeloid progenitors (GMP) and hematopoietic stem cells (HSC). Cancer stem cells (CSC) were created with MLL-ENL transfections using puromycin for both GMP and HSCs. Further knock-outs were created of -catenin (Ctnnb1) and Hoxa9.
2017-10-10 | E-MTAB-3647 | biostudies-arrayexpress
Project description:To determine the role of specific cis-regulatory elements within the Sox17 endoderm-preferential TSS2 promoter, we generated Sox17∆50 mutant animals and surveyed how this mutation altered Sox17 expression. Livers were isolated from E12.5 Sox17∆50/∆50 and Sox17+/+ embryos (n = 4 of each genotype), RNA isolated, and bulk RNA-Seq performed.
2024-10-31 | E-MTAB-13982 | biostudies-arrayexpress
Project description:To determine the role of specific cis-regulatory elements within the Sox17 endoderm-preferential TSS2 promoter, we generated Sox17∆50 mutant animals, crossed them to a Sox17GFPCre (a Sox17 null allele), and surveyed how this mutation affected Sox17 expression. Livers were isolated from E12.5 Sox17∆50/GFPCRe compound heterozygous and Sox17+/+ embryos (n = 4 of each genotype), RNA isolated, and bulk RNA-Seq performed.
2024-10-31 | E-MTAB-13983 | biostudies-arrayexpress
Project description:WNT/β-catenin signaling controls gene expression across biological contexts from development and stem cell homeostasis to diseases including cancer. How β-catenin is recruited to distinct enhancers to activate context-specific transcription is unclear, given that most WNT/ß-catenin-responsive transcription is thought to be mediated by TCF/LEF transcription factors (TFs). With time-resolved multi-omic analyses, we show that SOX TFs can direct lineage-specific WNT-responsive transcription during the differentiation of human pluripotent stem cells (hPSCs) into definitive endoderm and neuromesodermal progenitors. We demonstrate that SOX17 and SOX2 are required to recruit β-catenin to lineage-specific WNT-responsive enhancers, many of which are not occupied by TCFs. At TCF-independent enhancers, SOX TFs establish a permissive chromatin landscape and recruit a WNT-enhanceosome complex to activate SOX/ß-catenin-dependent transcription. Given that SOX TFs and the WNT pathway are critical for specification of most cell types, these results have broad mechanistic implications for the specificity of WNT responses across developmental and disease contexts.
| S-EPMC10123531 | biostudies-literature
Project description:To determine the role of specific cis-regulatory elements within the Sox17 endoderm-preferential TSS2 promoter, we generated Sox17∆50 mutant animals and surveyed how this mutation altered Sox17 expression. EPCAM+/CXCR4+ endodermal cells were isolated from E10.5 Sox17∆50/∆50 and Sox17+/+ embryos (n = 1 of each genotype). Posterior foregut and midgut regions of embryos were dissected by removal of embryonic head, heart, tail, limb buds, posterior and dorsal body trunk. Sox17+/+ and Sox17Δ50/Δ50 cell samples were labelled with barcodes from 3'CellPlex Kit (10X Genomics) and subsequently pooled together for single isolation, library preparation and sequencing.
2024-10-31 | E-MTAB-14000 | biostudies-arrayexpress