Megakaryocyte (MK) differentiation is well described in morphologic terms but its molecular counterparts and the basis for platelet release are incompletely understood. We profiled mRNA expression in populations of primary mouse MKs representing successive differentiation stages. Genes associated with DNA replication are highly expressed in young MKs, in parallel with endomitosis. Intermediate stages are characterized by disproportionate expression of genes associated with the cytoskeleton, cell migration and G-protein signaling, whereas terminally mature MKs accumulate hemostatic factors, including many membrane proteins. We used these expression profiles to extract a reliable panel of molecular markers for MKs of early, intermediate or advanced differentiation, and establish its value using mouse models of defective thrombopoiesis resulting from absence of GATA-1, NF-E2 or tubulin1. Computational analysis of the promoters of late-expressed MK genes identified new candidate targets for NF-E2, a critical transcriptional regulator of platelet release. One such gene encodes the kinase adaptor protein LIMS1/PINCH1, which is highly expressed in MKs and platelets and significantly reduced in NF-E2-deficient cells. Transactivation studies and chromatin immunoprecipitation implicate Lims1 as a direct target of NF-E2 regulation. Attribution of stagespecific genes, in combination with various applications, thus constitutes a powerful way to study MK differentiation and platelet biogenesis
Expression analysis of primary mouse megakaryocyte differentiation and its application in identifying stage-specific molecular markers and a novel transcriptional target of NF-E2.
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View SamplesDiverse functions of the homeodomain transcription factor BARX1 include Wnt-dependent, non-cell autonomous specification of the stomach epithelium, tracheo-bronchial septation, and Wnt-independent expansion of the spleen primordium. Tight spatio-temporal regulation of Barx1 levels in the mesentery and stomach mesenchyme suggests additional roles. To determine these functions, we forced constitutive BARX1 expression in the Bapx1 expression domain, which includes the mesentery and intestinal mesenchyme, and also examined Barx1-/- embryos in further detail. Transgenic embryos invariably showed intestinal truncation and malrotation, in part reflecting abnormal left-right patterning. Ectopic BARX1 expression did not affect intestinal epithelium, but intestinal smooth muscle developed with features typical of the stomach wall. BARX1, which is normally restricted to the developing stomach, drives robust smooth muscle expansion in this organ by promoting proliferation of myogenic progenitors at the expense of other sub-epithelial cells. Undifferentiated embryonic stomach and intestinal mesenchyme showed modest differences in mRNA expression and BARX1 was sufficient to induce much of the stomach profile in intestinal cells. However, limited binding at cis-regulatory sites implies that BARX1 may act principally through other transcription factors. Genes expressed ectopically in BARX1+ intestinal mesenchyme and reduced in Barx1-/- stomach mesenchyme include Isl1, Pitx1, Six2 and Pitx2, transcription factors known to control left-right patterning and influence smooth muscle development. The sum of evidence suggests that potent BARX1 functions in intestinal rotation and stomach myogenesis occur through this small group of intermediary transcription factors.
Control of stomach smooth muscle development and intestinal rotation by transcription factor BARX1.
Specimen part
View SamplesWe 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.
Essential and redundant functions of caudal family proteins in activating adult intestinal genes.
Specimen part
View SamplesTranscription factor Foxq1 controls mucin gene expression and granule content in mouse stomach surface mucous cells
Transcription factor foxq1 controls mucin gene expression and granule content in mouse stomach surface mucous cells.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Intestinal master transcription factor CDX2 controls chromatin access for partner transcription factor binding.
Specimen part
View SamplesWe established whether partner transcription factor binding, chromatin structure, or gene expression is compromised upon loss of partner factors cdx2 or hnf4a in mouse intestinal villi
Intestinal master transcription factor CDX2 controls chromatin access for partner transcription factor binding.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
DOT1L-mediated H3K79 methylation in chromatin is dispensable for Wnt pathway-specific and other intestinal epithelial functions.
Specimen part
View SamplesTo 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. Overall design: 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.
Distinct Processes and Transcriptional Targets Underlie CDX2 Requirements in Intestinal Stem Cells and Differentiated Villus Cells.
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View SamplesWe used microarrays to detail the differentail gene expression between intestinal Lgr5(hi) stem cells and differentiated cells
DOT1L-mediated H3K79 methylation in chromatin is dispensable for Wnt pathway-specific and other intestinal epithelial functions.
Specimen part
View SamplesColon cancers typically contain tumor cell populations with differential WNT signaling activity. Colon cancer cells with high WNT-activity have been attributed increase tumorigenic potential and stem cell characteristics.
Differential WNT activity in colorectal cancer confers limited tumorigenic potential and is regulated by MAPK signaling.
Specimen part, Cell line
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