The subunits of voltage-gated calcium channels regulate surface expression and gating of CaV1 and CaV2 1 subunits, and thus contribute to neuronal excitability, neurotransmitter release and calcium-induced gene regulation. In addition certain subunits are targeted into the nucleus, where they directly interact with the epigenetic machinery. Whereas their involvement in this multitude of functions is reflected by a great molecular heterogeneity of isoforms derived from four genes and abundant alternative splicing, little is known about the roles of individual variants in specific neuronal functions. In the present study, an alternatively spliced 4 subunit lacking the variable N-terminus (4e) is identified. It is highly expressed in mouse cerebellum and cultured cerebellar granule cells (CGC) and modulates P/Q-type calcium currents in tsA cells and CaV2.1 surface expression in neurons. Compared to the other two known full-length 4 variants (4a, 4b) 4e is most abundantly expressed in the distal axon, but lacks nuclear targeting properties. To examine the importance of nuclear targeting of 4 subunits for transcriptional regulation, we performed whole genome expression profiling of CGCs from lethargic mice individually reconstituted with 4a, 4b, and 4e. Notably, the number of genes regulated by each 4 splice variant correlated with the rank order of their nuclear targeting properties (4b> 4a> 4e). Together these findings support isoform-specific functions of 4 splice variant in neurons, with 4b playing a dual role in channel modulation and gene regulation, while the newly detected 4e variant serves exclusively in calcium channel-dependent functions.
Differential neuronal targeting of a new and two known calcium channel β4 subunit splice variants correlates with their regulation of gene expression.
Specimen part
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.
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View SamplesPrecise 5' splice site recognition is essential for both constitutive and regulated pre-mRNA splicing. The U1 snRNP specific protein U1C is involved in this first step of spliceosome assembly and important for stabilizing early splicing complexes. We used an embryonically lethal U1C knockout mutant zebrafish, hi1371, to investigate the potential genomewide role of U1C for splicing regulation. Surprisingly, genomewide RNA-Seq analysis of mutant versus wildtype embryos revealed a large set of specific target genes that changed their alternative splicing patterns in the absence of U1C. In sum, our findings provide evidence for a new role of a general snRNP protein, U1C, as a mediator of alternative splicing regulation.
RNA-Seq analysis in mutant zebrafish reveals role of U1C protein in alternative splicing regulation.
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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 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 SamplesIn order to understand how biochemical and genetic differences correlate with treatment response, we measured depressive-like behavior, gene expression and the levels of thirty-six neurobiochemical analytes across a panel of genetically-diverse mouse inbred lines after chronic treatment with vehicle or fluoxetine. Neurobiochemical markers were chosen based on their putative molecular function within pathways proposed to underlie depression, which include neuronal transmission, HPA-axis regulation, and neuroimmune processes. The goal of this study is to establish genetic and biochemical biomarkers that can predict treatment response and to propose a molecular pathway that is critical in mediating anti-depressant response.
Evaluating genetic markers and neurobiochemical analytes for fluoxetine response using a panel of mouse inbred strains.
Sex, 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 (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 Samples