Recent studies in our lab have identified a mutant mouse model of obstructive nephropathy designated mgb for megabladder. Homozygotic mgb mice (mgb-/-) develop lower urinary tract obstruction in utero due to a lack of bladder smooth muscle differentiation. This defect is the result of a random transgene insertion into chromosome 16 followed by a translocation of this fragment into chromosome 11. In an effort to identify potential gene targets affected in mgb mice, we performed transcriptional profiling on embryonic day 15 (E15) mgb-/- bladders using both a Chromosome 11/16 Custom GeneChip Array and the Affymetrix Mouse Genome 430 2.0 GeneChip. This analysis identified no definitive mis-expressed gene targets on chromosome 11. In contrast, mgb-/- mice significantly over-expressed a cluster of gene products located on the translocated fragment of chromosome 16 including urotensin II-related peptide (Urp), which was shown to be preferentially over-expressed in developing mgb-/- bladders. Immunohistochemical studies indicated that the spatial distribution of Urp was altered in mgb-/- bladders, while biochemical studies suggested a potential role for Urp in modifying smooth muscle cell phenotype in vitro. Pathway analysis of mgb microarray data showed dysregulation of at least 60 gene products associated with the differentiation of smooth muscle. In conclusion, the results of this study indicate that the molecular pathways controlling normal smooth muscle development are severely altered in mgb-/- bladders, and provide the first evidence that Urp may play a critical role in bladder smooth muscle development.
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View SamplesInterferon is effective at inducing complete remissions in patients with Chronic Myelogenous Leukemia (CML), and evidence supports an immune mechanism. Here we show that the Type I Interferons (alpha and beta) regulate expression of the Interferon consensus sequence binding protein (ICSBP) in bcr-abl transformed cells and as shown previously for ICSBP, induce a vaccine-like immunoprotective effect in a murine model of bcr-abl induced leukemia. We identify the chemokines CCL6 and CCL9 as genes prominently induced by the Type I Interferons and ICSBP, and demonstrate that these immunomodulators are required for the immunoprotective effect of ICSBP expression. Insights into the role of these chemokines in the anti-leukemic response of interferons suggest new strategies for immunotherapy of CML.
ICSBP-mediated immune protection against BCR-ABL-induced leukemia requires the CCL6 and CCL9 chemokines.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part, Disease, Cell line, Treatment
View SamplesOrigins of the brain tumor, medulloblastoma, from stem cells or restricted pro-genitor cells are unclear. To investigate this, we activated oncogenic Hedgehog signaling in multipotent and lineage-restricted CNS progenitors. We observed that normal unipo-tent cerebellar granule neuron precursors (CGNP) derive from hGFAP+ and Olig2+ rhombic lip progenitors. Hedgehog activation in a spectrum of early and late stage CNS progenitors generated similar medulloblastomas, but not other brain cancers, indicating that acquisition of CGNP identity is essential for tumorigenesis. We show in human and mouse medulloblastoma that cells expressing the glia-associated markers Gfap and Olig2 are neoplastic and that they retain features of embryonic-type granule lineage progenitors. Thus, oncogenic Hedgehog signaling promotes medulloblastoma from lineage-restricted granule cell progenitors.
Acquisition of granule neuron precursor identity is a critical determinant of progenitor cell competence to form Shh-induced medulloblastoma.
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View SamplesCalcium signaling is a central regulator of cardiomyocyte growth and function. Calmodulin is a critical mediator of calcium signals. Because the amount of calmodulin within cardiomyocytes is limiting, precise regulation of calmodulin expression may be an important for regulation of calcium signaling. In this study, we show for the first time that calmodulin levels are regulated post-transcriptionally in heart failure. The cardiomyocyte-restricted microRNA miR-1 inhibited translation of calmodulin-encoding mRNAs via highly conserved target sites within their 3-untranslated regions. In keeping with its effect on calmodulin expression, miR-1 downregulated calcium-calmodulin signaling through the calcineurin to NFAT. miR-1 also negatively regulated expression of Mef2a and Gata4, key transcription factors that mediate calcium-dependent changes in gene expression. Consistent with downregulation of these hypertrophy-associated genes, miR-1 attenuated cardiomyocyte hypertrophy in cultured neonatal rat cardiomyocytes and in the intact adult heart. Our data indicate that miR-1 regulates cardiomyocyte growth responses by negatively regulating the calcium-signaling components calmodulin, Mef2a, and Gata4.
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Cell line, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Human fetal hemoglobin expression is regulated by the developmental stage-specific repressor BCL11A.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Microcephaly gene links trithorax and REST/NRSF to control neural stem cell proliferation and differentiation.
Time
View SamplesThe progression from stem cell to differentiated neuron is associated with extensive chromatin remodeling that controls gene expression, but the mechanisms that connect chromatin to gene expression are not well defined. Here we show that mutation of ZNF335 causes severe human microcephaly ("small brain"), small somatic size, and neonatal death. Germline Znf335 null mutations are embryonically lethal in mice, whereas RNA-interference studies and postmortem human studies show that Znf335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. Znf335 is a component of a vertebrate-specific, trithorax H3K4 methylation complex, while global ChIP-seq and mRNA expression studies show that Znf335 is a previously unsuspected, direct regulator of REST/NRSF, a master regulator of neural gene expression and neural cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF, and provide the first direct evidence that this pathway regulates human neurogenesis and neuronal differentiation.
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Time
View SamplesIn this project, we studied a mouse model of human Down Syndrome (DS) megakaryocytic leukemia involving mutations in the GATA1 transcription factor (called GATA1s mutation). The model was generated through retroviral insertional mutagenesis in Gata1s mutant fetal liver progenitors. In this study, we analyzed the dependency of these leukemic cells on the Gata1s mutant protein.
Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.
Specimen part, Cell line, Treatment
View SamplesBergmann glial cells of the vertebrate cerebellum play essential roles in the development and maintenance of cerebellar structure and function. During development, Bergmann glia provide structural support to the expanding cerebellar anlage and also serve as guides for migrating neurons (granule cells). As the cerebellum matures, Bergmann glia become important in dendritic arborization, synapse maintenance and synaptic function. The molecular mechanisms underlying these diverse and important functions of Bergmann glia remain largely unknown.
Identification of novel glial genes by single-cell transcriptional profiling of Bergmann glial cells from mouse cerebellum.
Specimen part
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