Distinct processes and transcriptional targets underlie CDX2 requirements in intestinal stem cells and differentiated villus cells
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ABSTRACT: To define target genes of the intestine-restricted transcription factor (TF) CDX2 in intestinal stem cells, we performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq). We used RNA-sequencing to profile gene expression changes during cell differentiation from mouse intestinal stem cells to mature villus cells, as well as genes perturbed in intestinal stem cells upon loss of Cdx2. We find thousands of genes that change in expression during cell differentiation, including known stem cell and mature markers. Upon loss of Cdx2, hundreds of genes are up and down-regulated in intestinal stem cells, some of which are also bound by CDX2 nearby and constitute candidate direct target genes.
Project description:To define target genes of the intestine-restricted transcription factor (TF) CDX2 in intestinal stem cells, we performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq). We used RNA-sequencing to profile gene expression changes during cell differentiation from mouse intestinal stem cells to mature villus cells, as well as genes perturbed in intestinal stem cells upon loss of Cdx2. We find thousands of genes that change in expression during cell differentiation, including known stem cell and mature markers. Upon loss of Cdx2, hundreds of genes are up and down-regulated in intestinal stem cells, some of which are also bound by CDX2 nearby and constitute candidate direct target genes. CDX2 ChIP-Seq analysis of isolated mouse intestinal stem cells. RNA seq analysis of control mouse villus cells, control intestinal stem cells and Cdx2-deleted intestinal stem cells.
Project description:We conditionally inactivated mouse Cdx2, a dominant regulator of intestinal development, and mapped its genome occupancy in adult intestinal villi. Although homeotic transformation, observed in Cdx2-null embryos, was absent in mutant adults, gene expression and cell morphology were vitally compromised. Lethality was accelerated in mice lacking both Cdx2 and its homolog Cdx1, with exaggeration of defects in crypt cell replication and enterocyte differentiation. Cdx2 occupancy correlated with hundreds of transcripts that fell but not with equal numbers that rose with Cdx loss, indicating a predominantly activating role at intestinal cis-regulatory regions. Integrated consideration of a mutant phenotype and cistrome hence reveals the continued and distinct requirement in adults of a master developmental regulator that activates tissue-specific genes. Cdx2 ChIP-seq in mouse villus, and gene expression data from Cdx1, Cdx2 and compound knockout mouse intestine
Project description:Genes encoding transcription factors function as hubs in gene regulatory networks because they encode DNA-binding proteins, which bind to promoters that carry their binding sites. In the present work we have studied gene regulatory networks defined by genes with transcripts belonging to different mRNA abundance classes in the small intestinal epithelial cell. The focus is the rewiring that occurs in transcription factor hubs in these networks during the differentiation of the small intestinal epithelial cell while it migrates along the crypt-villus axis and during its development from a fetal endodermal cell to a mature adult villus epithelial cell. We have generated transcriptome data for mouse small intestinal villus, crypt and fetal intestinal epithelial cells. In addition we have generated metabolome data from crypt and villus cells. Our results show that the intestinal crypt transcription factor hubs that are rewired during differentiation are involved in the cell cycle process (E2F, NF-Y) and stem cell maintenance (c-Myc). In contrast the villi are dominated by a HNF-4 villus hub, which is rewired during differentiation by the addition of network genes with relevance for lipoprotein synthesis and lipid absorption. Moreover, we have identified a villus NF-kB hub, which was revealed by comparison of the villus and endoderm transcriptomes. The rewiring of the NF-kB villus hub during intestinal development reflects transcriptional activity established by host and microflora interactions. To aid in the mining of our results we have developed a web portal (http://gastro.imbg.ku.dk/mousecv/) allowing easy linkage between the transcriptomic data, biological processes and functions. Keywords: Cell type comparison
Project description:We conditionally inactivated mouse Cdx2, a dominant regulator of intestinal development, and mapped its genome occupancy in adult intestinal villi. Although homeotic transformation, observed in Cdx2-null embryos, was absent in mutant adults, gene expression and cell morphology were vitally compromised. Lethality was accelerated in mice lacking both Cdx2 and its homolog Cdx1, with exaggeration of defects in crypt cell replication and enterocyte differentiation. Cdx2 occupancy correlated with hundreds of transcripts that fell but not with equal numbers that rose with Cdx loss, indicating a predominantly activating role at intestinal cis-regulatory regions. Integrated consideration of a mutant phenotype and cistrome hence reveals the continued and distinct requirement in adults of a master developmental regulator that activates tissue-specific genes.
Project description:Genes encoding transcription factors function as hubs in gene regulatory networks because they encode DNA-binding proteins, which bind to promoters that carry their binding sites. In the present work we have studied gene regulatory networks defined by genes with transcripts belonging to different mRNA abundance classes in the small intestinal epithelial cell. The focus is the rewiring that occurs in transcription factor hubs in these networks during the differentiation of the small intestinal epithelial cell while it migrates along the crypt-villus axis and during its development from a fetal endodermal cell to a mature adult villus epithelial cell. We have generated transcriptome data for mouse small intestinal villus, crypt and fetal intestinal epithelial cells. In addition we have generated metabolome data from crypt and villus cells. Our results show that the intestinal crypt transcription factor hubs that are rewired during differentiation are involved in the cell cycle process (E2F, NF-Y) and stem cell maintenance (c-Myc). In contrast the villi are dominated by a HNF-4 villus hub, which is rewired during differentiation by the addition of network genes with relevance for lipoprotein synthesis and lipid absorption. Moreover, we have identified a villus NF-kB hub, which was revealed by comparison of the villus and endoderm transcriptomes. The rewiring of the NF-kB villus hub during intestinal development reflects transcriptional activity established by host and microflora interactions. To aid in the mining of our results we have developed a web portal (http://gastro.imbg.ku.dk/mousecv/) allowing easy linkage between the transcriptomic data, biological processes and functions. Experiment Overall Design: Four different sample categories were analyzed. Experiment Overall Design: 1) Small intestinal crypts isolated form 12-weeks old C57BL/6 mice. These samples are in triplicates. Experiment Overall Design: 2) Small intestinal villi isolated form 12-weeks old C57BL/6 mice. These samples are in triplicates. Experiment Overall Design: 3) Embryonic day 12 mesenchyme. These samples are in quadruplicate. each sample is derived from a pool of mesenchymes (10-40) Experiment Overall Design: 4) Embryonic day 12 endoderm. These samples are in quadruplicate. each sample is derived from a pool of endoderms (10-40)
Project description:Methylation of H3K79 is associated with chromatin at expressed genes, though it is unclear if this histone modification is required for transcription of all genes. Recent studies suggest that Wnt-responsive genes depend particularly on H3K79 methylation, which is catalyzed by the methyltransferase DOT1L. Human leukemias carrying MLL gene rearrangements show DOT1L-mediated H3K79 methylation and aberrant expression of leukemogenic genes. DOT1L inhibitors reverse these effects but their clinical use is potentially limited by toxicity in Wnt-dependent tissues such as intestinal epithelium. Genome-wide positioning of the H3K79me2 mark in Lgr5+ mouse intestinal stem cells and mature intestinal villus epithelium correlated with mRNA expression levels but not with Wnt-responsive genes per se. Selective Dot1l disruption in Lgr5+ stem cells or in all intestinal epithelial cells eliminated H3K79me2 from the respective compartments, allowing genetic evaluation of DOT1L requirements. Absence of methylated H3K79 did not impair health, intestinal homeostasis or expression of Wnt target genes in crypt epithelium for up to 4 months, despite increased crypt cell apoptosis. Global transcript profiles in Dot1l-null cells were barely altered. Thus, H3K79 methylation is not essential for transcription of Wnt-responsive or other intestinal genes and intestinal toxicity is not imperative when DOT1L is rendered inactive in vivo. Examination of differential gene expression between Dot1l control (Dot1 f/f) and Dot1l mutant (Villin-Cre, Dot1l f/f) villus cells.
Project description:H3K79me2 ChIP-seq in mouse proximal intestinal Lgr5(hi) stem cells and villus cells Examination of H3K79me2 modifications between Lgr5(hi) stem cells and differentiated villus cells
Project description:The endodermal lining of the adult gastro-intestinal tract harbors stem cells that are responsible for the day-to-day regeneration of the epithelium. Stem cells residing in the pyloric glands of the stomach and in the small intestinal crypts differ in their differentiation program and in the gene repertoire that they express. Both types of stem cells have been shown to grow from single cells into 3D structures (organoids) in vitro. We show that single adult Lgr5-positive stem cells, isolated from small intestinal organoids, require Cdx2 to maintain their intestinal identity and are converted cell-autonomously into pyloric stem cells in the absence of this transcription factor. Clonal descendants of Cdx2null small intestinal stem cells enter the gastric differentiation program instead of producing intestinal derivatives. Conversely, forced expression of Cdx2 in gastric organoids results in their intestinalization. The intestinal genetic program is thus critically dependent on the single transcription factor encoding gene Cdx2. Small intestinal crypts and stomach glands were isolated from Cdx2-/fl / Lgr5-EGFP-CreERT2 mice and cultured for a week in order to generate small intestinal (SI) and stomach (Sto) in vitro organoids. The Lgr5-CreERT2 enzyme activity has been induced by overnight 4-hydroxytamoxifen induction. Tamoxifen treated and untreated Lgr5-EGFPhi SI and Sto stem cells were FACS sorted and seeded back into ENRWfg (Sto med) culture conditions in order to generate Cdx2-/fl small intestinal (Control SI), Cdx2null small intestinal (Cdx2null SI) and Cdx2-/fl stomach (Control Sto) clonal organoids. Cdx2-/fl SI organoids and Cdx2-/fl Sto organoids have been also cultured in ENR (SI med) to induce differentiation. After some passages of clonal organoid expansion, RNA was isolated from Control SI, Cdx2null SI and Control Sto Lgr5-EGFPhi FACS sorted stem cell populations and from smal intestinal and stomach organoids cultured in different conditions and hybridized on Affymetrix Mouse Gene ST 1.1 arrays.