Recent studies have documented genome-wide binding patterns of transcriptional regulators and their associated epigenetic marks in hematopoietic cell lineages. In order to determine how epigenetic marks are established and maintained during developmental progression, we have generated long-term cultures of hematopoietic progenitors by enforcing the expression of the E-protein antagonist Id2. Hematopoietic progenitors that express Id2 are multipotent and readily differentiate upon withdrawal of Id2 expression into committed B lineage cells, thus indicating a causative role for E2A (Tcf3) in promoting the B cell fate. Genome-wide analyses revealed that a substantial fraction of lymphoid and myeloid enhancers are premarked by the poised or active enhancer mark H3K4me1 in multipotent progenitors. Thus, in hematopoietic progenitors, multilineage priming of enhancer elements precedes commitment to the lymphoid or myeloid cell lineages.
Multilineage priming of enhancer repertoires precedes commitment to the B and myeloid cell lineages in hematopoietic progenitors.
Specimen part
View SamplesRecent studies have documented genome-wide binding patterns of transcriptional regulators and their associated epigenetic marks in hematopoietic cell lineages. In order to determine how epigenetic marks are established and maintained during developmental progression, we have generated long-term cultures of hematopoietic progenitors by enforcing the expression of the E-protein antagonist Id2. Hematopoietic progenitors that express Id2 are multipotent and readily differentiate upon withdrawal of Id2 expression into committed B lineage cells, thus indicating a causative role for E2A in promoting the B cell fate. Genome-wide analyses revealed that a substantial fraction of lymphoid and myeloid enhancers are pre-marked by H3K4me1 in multipotent progenitors. However, H3K4me1 levels at a subset of enhancers are elevated during developmental progression, resulting in evolving enhancer repertoires that we propose orchestrate the myeloid and B cell fates.
Multilineage priming of enhancer repertoires precedes commitment to the B and myeloid cell lineages in hematopoietic progenitors.
Specimen part
View SamplesImmortalized, amelanotic melanocytes isolted from skin of Balb/c express enzymatically-inactive tyrosinase due to a homozygous point mutation (TGT->TCT) in tyrosinase gene, resulting in a lack of melanin . To serve as a control cell line, pigmentation was restored in these cells by correcting the point mutation using an RNA-DNA oligonucleotide (kingly gift from Dr. Alexeev Y. Vitali).
Melanocyte-secreted fibromodulin promotes an angiogenic microenvironment.
Specimen part
View SamplesmiR-92 enhances c-Myc induced apoptosis. In the R26MER/MER mouse embryonic fibroblasts (MEFs), a switchable variant of Myc, MycERT2, was knocked into the genomic region downstream of the constitutive Rosa26 promoter, allowing acute activation of c-Myc by 4-OHT-induced nuclear translocation. This in vitro system nicely recapitulates c-Myc-induced apoptosis, as activated MycERT2 induces strong p53-dependent apoptosis in response to serum starvation. Enforced miR-92 expression in three independent R26MER/MER MEF lines significantly enhanced Myc-induced apoptosis.
A component of the mir-17-92 polycistronic oncomir promotes oncogene-dependent apoptosis.
Specimen part
View SamplesHearts Lacking Caveolin-1 Develop Hypertrophy with Normal Cardiac Substrate Metabolism
Hearts lacking caveolin-1 develop hypertrophy with normal cardiac substrate metabolism.
No sample metadata fields
View SamplesThe aim of this study was to determine the effect of transgenic Aire expression on the transcriptional profile of a tissue that normally does not express Aire: pancreatic islets. The transcriptional profile of transgenic RIP-Aire27 islets was compared to non-transgenic littermate islets as well as to archival NOD thymic medullary epithelial cells (MEC) data. All data were from non-obese diabetic (NOD) mice
Transcriptional impact of Aire varies with cell type.
No sample metadata fields
View SamplesRAS oncogenic mutations are common in human cancers, but RAS proteins have been difficult to target. We sought to identify pharmacological agents to block the RAS oncogenic signaling by a distinct mechanism. Since the biological activity of RAS proteins rely upon lipid modifications and RAS regulates lipid metabolisms in cancer cells, we screened a bioactive lipid library using a RAS specific cell viability assay. We report the discovery of a new class of inhibitors for RAS transformation. Compounds in the class represented by endocannabinoid N-arachidonoyl dopamine (NADA) can induce cell oncosis, independent of its ability to engage cannabinoid receptors. Further analyses show that NADA is more active in inhibiting the NRAS transformation and signaling than that of KRAS4B. Mechanistically, NADA blocks the plasma membrane translocation of NRAS, but not that of KRAS4B. In addition, NADA inhibits the plasma membrane translocation and neoplastic transformation of oncogenic KRAS4A. Interestingly, NADA also redistributes the cytoplasmic NRAS to the Golgi apparatus in a palmitoylation-dependent manner. The results indicate that NADA inhibits NRAS and KRAS4A plasma membrane translocation by targeting a novel molecular process. The new findings would help to develop novel targeted therapies for a broad range of human cancers.
N-Arachidonoyl Dopamine Inhibits NRAS Neoplastic Transformation by Suppressing Its Plasma Membrane Translocation.
No sample metadata fields
View SamplesFollowing the identification of a critical time window of Blood Brain Barrier formation in the mouse embryo, we aimed to identify genes important for barriergenesis. To this end, we isolated cortical and lung E13.5 endothelial cells and compared expression between the two populations.
Mfsd2a is critical for the formation and function of the blood-brain barrier.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reprogramming of the microRNA transcriptome mediates resistance to rapamycin.
Specimen part, Cell line
View SamplesThe mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation. Inhibitors of mTOR are being evaluated as anti-tumor agents. Given the emerging role of microRNAs (miRNAs) in tumorgenesis we hypothesized that miRNAs could play important roles in the response of tumors to mTOR inhibitors. Rapamycin resistant myogenic cells developed by long-term rapamycin treatment showed extensive reprogramming of miRNAs expression, characterized by up-regulation of the mir-17~92 and related clusters and down-regulation of tumor-suppressor miRNAs. Antagonists of oncogenic miRNA families and mimics of tumor suppressor miRNAs (let-7) restored rapamycin sensitivity in resistant tumor cells. This study identified miRNAs as new downstream components of the mTOR-signaling pathway, which may determine the response of tumors to mTOR inhibitors.
Reprogramming of the microRNA transcriptome mediates resistance to rapamycin.
Specimen part, Cell line
View Samples