Glioblastoma, the most aggressive and least treatable form of malignant glioma, is the most common human brain tumor. Although many regions of allelic loss occur in glioblastomas, relatively few tumor suppressor genes have been found mutated at such loci. To address the possibility that epigenetic alterations are an alternative means of glioblastoma gene inactivation, we coupled pharmacological manipulation of methylation with gene profiling to identify potential methylation-regulated, tumor-related genes. Triplicates of three short-term cultured glioblastomas were exposed to 5M 5-aza-dC for 96 hours followed by cRNA hybridization to an oligonucleotide microarray (Affymetrix U133A). We based candidate gene selection on bioinformatics, RT-PCR, bisulfite sequencing, methylation-specific PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Two genes identified in this manner, RUNX3 and Testin (TES), were subsequently shown to harbor frequent tumor-specific epigenetic alterations in primary glioblastomas. This overall approach therefore provides a powerful means to identify candidate tumor suppressor genes for subsequent evaluation and may lead to the identification of genes whose epigenetic dysregulation is integral to glioblastoma tumorigenesis.
Downregulation of RUNX3 and TES by hypermethylation in glioblastoma.
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View SamplesComparison of gene expression in post-mortem hippocampus from 20 alcoholics and 19 controls.
Stress-response pathways are altered in the hippocampus of chronic alcoholics.
Sex, Age, Specimen part
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 SamplesThe transition of skotomorphogenesis to photomorphogenesis is induced by the perception of light and is characterized by the inhibition of hypocotyl elongation and opening of cotyledons. Although it is known that the plant hormone cytokinin, when applied in high concentrations, inhibits hypocotyl elongation in the dark-grown Arabidopsis plants, it is unclear to what extent this response is the result of cytokinin alone or cytokinin-induced ethylene production. We show that treatment of etiolated seedlings in presence of ethylene inhibitors (eg. AgNO3) or treatment of the ethylene-resistant mutant ein2, resulted in a significant inhibition of hypocotyl elongation. This indicates that cytokinin induced de-etiolation is largely independent of ethylene and suggests a close connection between the cytokinin two component system and the light singalling networks. We show that this cytokinin signal is mainly mediated through the cytokinin receptor ARIBIDOPSIS HISTIDIN KINASE 3 (AHK3) and the ARABIDOPSIS RESPONSE REGULATORS 1 (ARR1) in combination with ARR12. Interestingly, mutation of COP1, DET1 and CIN4/COP10 renders plants insensitive to cytokinin and these factors are indispensable for the transcriptional response during cytokinin induced de-etiolation which indicates that a functional light signaling pathway is essential for this cytokinin response. In addition, the cytokinin effect on hypocotyl elongation is highly dependent on the ambient light conditions where higher light intensities causes a switch in the response to CK from an inhibitor to a promoter of hypocotyl elongation. Overall design: Investigation of the effect of 3 µM BA in presence of 10 µM AgNO3 on hypocotyl elongation in 4-days-old etiolated Arabidopsis seedlings, in triplicate, using RNA-seq analysis
Ethylene-independent promotion of photomorphogenesis in the dark by cytokinin requires COP1 and the CDD complex.
Age, Specimen part, Treatment, Subject
View SamplesThe thymic microenvironment is essential for proper differentiation and selection of thymocytes.Thymic involution in aged mice results in decreased T cell output and immune function. Here we use gene expression profiling of FACS sorted thymic stromal subsets to identify molecular mediators of thymocyte: stromal cell interactions, as well as gene expression changes thymic stromal subsets during early stages of thymic involution .
Global transcriptional profiling reveals distinct functions of thymic stromal subsets and age-related changes during thymic involution.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesPlasticity between adhesive and less-adhesive states is important for mammalian cell behaviour. To investigate adhesion plasticity, we have selected a stable isogenic subpopulation of MDA-MB-468 breast carcinoma cells which grows in suspension. These suspension cells are unable to re-adhere to various matrices or to contract three-dimensional collagen lattices.
A dual phenotype of MDA-MB-468 cancer cells reveals mutual regulation of tensin3 and adhesion plasticity.
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View SamplesAbstract: Transcriptome analysis was applied to characterize the physiological activities of Pseudomonas aeruginosa grown for three days in drip-flow biofilm reactors. Conventional applications of transcriptional profiling often compare two paired data sets that differ in a single experimentally controlled variable. In contrast this study obtained the transcriptome of a single biofilm state, ranked transcript signals to make the priorities of the population manifest, and compared rankings for a priori identified physiological marker genes between the biofilm and published data sets.
Physiology of Pseudomonas aeruginosa in biofilms as revealed by transcriptome analysis.
Treatment
View SamplesRNA sequencing was used to identify genome wide transcriptional changes occurring in the Drosophila mushroom body in juvenile and mature adult flies expressing a mushroom body-specific RNAi knockdown of Bap60. The results of this analysis suggested a role for Bap60 in the regulation of neurodevelopmental genes during a critical time window of juvenile adult brain development. Overall design: RNA from mushroom body nuclei was sequenced from Drosophila melanogaster expressing a mushroom body-specific RNAi knockdown of Bap60 or mCherry (control) in both juvenile (2 and 3 replicates, respectively) and mature (5 replicates each) adult flies.
A Syndromic Neurodevelopmental Disorder Caused by Mutations in SMARCD1, a Core SWI/SNF Subunit Needed for Context-Dependent Neuronal Gene Regulation in Flies.
Sex, Disease, Subject
View SamplesUsing a mouse model overexpressing human SNCA and profiling the hippocampal transcriptome, we assessed gene-environment interactions to reveal perturbations in gene expression and their modulation through long-term enriched environment (EE) exposure. We observed that EE prevented perturbations of genes attributed to neuronal and glial cell types and linked to glutamate signaling, calcium homeostasis, inflammation, and related processes of SNCA biology. Cluster and promoter analyses suggested driver genes that specifically responded to the EE, and pointed to a pivotal role of Egr1 to have hierarchically activated other drivers. We suggest a model in which EE-induced driver genes prevent and counter-balance perturbations of SNCA overexpression, restoring a largely normalized gene expression profile and system state. Overall design: Using a 2x2 factorial design, we cross-compared a line of transgenic mice overexpressing human SNCA with wildtype animals, and the effects of a long-term EE with standard housing conditions. Employing RNA-seq, we profiled gene expression in the hippocampus of 12-month-old female animals.
Environmental Enrichment Prevents Transcriptional Disturbances Induced by Alpha-Synuclein Overexpression.
Age, Specimen part, Cell line, Subject
View SamplesThe gene expression pathways leading to muscle pathology in facioscapulohumeral dystrophy (FSHD) remain to be elucidated. This muscular dystrophy is caused by a contraction of an array of tandem 3.3-kb repeats (D4Z4) at 4q35.2. We compared expression of control and FSHD myoblasts and myotubes (three preparations each) on exon microarrays (Affymetrix Human Exon 1.0 ST) and validated FSHD-specific differences for representative genes by qRT-PCR on additional myoblast cell strains. The FSHD and control myoblasts used for these experiments were shown to grow and differentiate into myotubes equally efficiently as control myoblasts. There were no significant FSHD-control differences in RNA levels for MYOD1 and MYOG at the myoblast and myotube stages and for MYF5 and MYF6 at the myoblast stage. In contrast, 295 other genes were dysregulated at least 2-fold in FSHD vs. control myoblasts (p <0.01, adjusted for multiple comparisons).
Gene expression during normal and FSHD myogenesis.
Specimen part
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