Proper functioning of tissues requires cells to behave in uniform, well-organized ways. Conversely, many diseases involve increased cellular heterogeneity due to genetic and epigenetic alterations. Defining the mechanisms that counteract phenotypic variability is therefore critical to understand how tissues sustain homeostasis. Here, we carried out a single-cell resolution screen of zebrafish embryonic blood vessels upon mutagenesis of single microRNA (miRNA) genes and multi-gene miRNA families. We found that miRNA mutants exhibit a profound increase in cellular phenotypic variability of specific vascular traits. Genome-wide analysis of endothelial miRNA target genes identified antagonistic regulatory nodes of vascular growth and morphogenesis signaling that allow variable cell behaviors when derepressed. Remarkably, lack of such miRNA activity greatly sensitized the vascular system to microenvironmental changes induced by pharmacological stress. We uncover a previously unrecognized role of miRNAs as a widespread protective mechanism that limits variability in cellular phenotypes. This discovery marks an important advance in our comprehension of how miRNAs function in the physiology of higher organisms. Overall design: Analysis of differential genes expression in Zebrafish endothelial cells for 4 different developmental stages
MicroRNAs Establish Uniform Traits during the Architecture of Vertebrate Embryos.
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View SamplesIn this dataset, we include the expression data obtained from KRas expressing tumors, matched Kras expressing tumor spheres, surviving cells and surviving cells after KRas re-expression for 24hs
Oncogene ablation-resistant pancreatic cancer cells depend on mitochondrial function.
Specimen part
View SamplesOocyte maturation is accompanied by a transition from mRNA stability to instability. We investigated the role of DCP1A and DCP2, proteins responsible for mRNA decapping, in mRNA destabilization during mouse oocyte maturation.
Maternally recruited DCP1A and DCP2 contribute to messenger RNA degradation during oocyte maturation and genome activation in mouse.
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View SamplesSmall RNAs, such as miRNAs and siRNAs, are involved in gene regulation in a variety of systems, including mouse oocytes. Dicer is a ribonuclease III enzyme essential for miRNA and siRNA biosynthesis. In an effort to uncover the function of small RNAs during oocyte growth, we specifically deleted Dicer in growing oocytes and analyzed the global pattern of gene expression in these Dicer-deficient oocytes.
MicroRNA activity is suppressed in mouse oocytes.
Sex, Specimen part
View SamplesCell differentiation requires epigenetic modulation of tissue-specific genes and activities of master transcriptional regulators, which are recognized for their dominant control over cellular programs. Using novel epigenomic methods, we characterized enhancer elements specifically modified in differentiating intestinal epithelial cells and found enrichment of transcription factor-binding motifs corresponding to CDX2, a master regulator of the intestine. Directed investigation revealed surprising lability in CDX2 occupancy of the genome, with redistribution from hundreds of sites occupied only in progenitors to thousands of new sites in mature cells. Knockout mice confirmed distinct Cdx2 requirements in dividing and differentiated adult intestinal cells, including responsibility for the active enhancer configuration associated with maturity. Dynamic CDX2 occupancy corresponds with condition-specific gene expression and, importantly, to differential co-occupancy with other tissue-restricted transcription factors: HNF4A in mature cells and GATA6 in progenitors. These results reveal dynamic, context-specific functions and mechanisms of a master transcription factor within a cell lineage.
Differentiation-specific histone modifications reveal dynamic chromatin interactions and partners for the intestinal transcription factor CDX2.
Specimen part, Cell line
View SamplesA major goal in prostate stem cell biology is to identify genes, pathways, or networks that control self-renewal and multilineage differentiation. We hypothesize that 1,25 dihydroxyvitamin D3 can induce differentiation of prostatic progenitor/stem cells, thus serving as an in vitro model with which to study the molecular mechanisms of stem cell differentiation by 1,25 dihydroxyvitamin D3. 1,25 dihydroxyvitamin D3 elicits its effects primarily through transcriptional regulation of genes, so microarray studies were used to gain insight into the cellular response to 1,25 dihydroxyvitamin D3.
Interleukin-1α mediates the antiproliferative effects of 1,25-dihydroxyvitamin D3 in prostate progenitor/stem cells.
Specimen part
View SamplesGlucocorticoids control expression of a large number of genes after binding to the glucocorticoid receptor (GR). Transcription may be regulated either by binding of the GR dimer to DNA regulatory elements or by protein-protein interactions of GR monomers with other transcription factors. Although the type of regulation for a number of individual target genes is known, the relative contribution of both mechanisms to the regulation of the entire transcriptional program remains elusive.
Prednisolone-induced differential gene expression in mouse liver carrying wild type or a dimerization-defective glucocorticoid receptor.
Sex, Specimen part
View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses, gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
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View SamplesThe four transcription factors Oct4, Sox2, Klf4, and c-Myc can induce pluripotency in mouse and human fibroblasts. We previously described direct reprogramming of adult mouse neural stem cells (NSCs) by Oct4 and either Klf4 or c-Myc. NSCs endogenously express Sox2, c-Myc, and Klf4 as well as several intermediate reprogramming markers. Here we report that exogenous expression of the germline-specific transcription factor Oct4 is sufficient to generate pluripotent stem cells from adult mouse NSCs. These one-factor induced pluripotent stem (1F iPS) cells are similar to embryonic stem cells in vitro and in vivo. Not only can these cells be efficiently differentiated into NSCs, cardiomyocytes and germ cells in vitro, but they are also capable of teratoma formation and germline transmission in vivo. Our results demonstrate that Oct4 is required and sufficient to directly reprogram NSCs to pluripotency.
Oct4-induced pluripotency in adult neural stem cells.
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View SamplesAlmost all human pancreatic ductal adenocarcinomas (PDACs) are driven by oncogenic Kras and the progression of the disease is characterized by the serial appearance of certain genetic lesions. Mouse models have convincingly shown that Kras mutation induces classical PanIN lesions that can progress to PDAC in the appropriate tumor suppressor background. However, the cooperative mechanism between mutant Kras-dependent signaling surrogates and other oncogenic pathways remains to be fully elucidated in order to devise better therapeutic strategy. Mounting evidence PTEN/PI3K perturbation on PDAC tumorigenesis, we observed frequent PTEN inactivation at both genomic and histopathological levels in primary human PDAC samples. The importance of PTEN/PI3K pathway during the development of PDAC was further supported by genetic studies demonstrating that Pten deficiency in cooperation with Kras activation accelerated the formation of invasive PDAC. Mechanistically, combined Kras mutation and Pten inactivation leads to NFkB activation and subsequent induction of cytokine pathways, accompanied with strong stromal activation and immune cell infiltration. Therefore, PTEN/PI3K pathway dictates the activity of NFkB network and serves as a major surrogate during Kras-mediated pancreatic tumorigenesis.
PTEN is a major tumor suppressor in pancreatic ductal adenocarcinoma and regulates an NF-κB-cytokine network.
Specimen part
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