Gene expression array analysis component. Ligand-dependent transcription by the nuclear receptor glucocorticoid receptor (GR) is mediated by interactions with co-regulators. The role of these interactions in determining selective binding of GR to regulatory elements remains unclear. Recent findings indicate a large fraction of genomic GR binding coincides with chromatin that is accessible prior to hormone treatment, suggesting that receptor binding is dictated by proteins that maintain chromatin in an open state. Combining nucleolytic cleavage and chromatin immunoprecipitation with high-throughput sequencing, we identify the activator protein 1 (AP1) as a major partner for productive GR-chromatin interactions. AP1 is critical for GR-regulated transcription and recruitment to co-occupied regulatory elements, illustrating an extensive AP1-GR interaction network. Importantly, the maintenance of baseline chromatin accessibility facilitates GR recruitment and is dependent on AP1 binding. We propose a model where the basal occupancy of transcription factors act to prime chromatin and direct inducible transcription factors to select regions in the genome.
Transcription factor AP1 potentiates chromatin accessibility and glucocorticoid receptor binding.
Sex, Cell line, Treatment, Time
View SamplesThere is a good deal of indirect evidence that improved insulin sensitivity may contribute to improved lifespan of mice in which aging has been slowed by mutations, drugs, or dietary means, even in stocks of mice that do not show signs of late-life diabetes. Peripheral responses to insulin can be augmented by over-expression of Syntaxin 4 (Syn4), a membrane SNARE protein. We show here that Syn4 transgenic (Tg) mice live approximately 33% longer than controls, and show increased peripheral insulin sensitivity, even at ages where controls show age-related insulin resistance. Hence, presumably Syn4 Tg mice spend more hours of each day under normoglycemic conditions, which may slow multiple aspects of aging and thereby extend lifespan, even in non-diabetic mice.
Syntaxin 4 Overexpression Ameliorates Effects of Aging and High-Fat Diet on Glucose Control and Extends Lifespan.
Sex, Specimen part
View SamplesNa+/H+ exchanger 3 (NHE3) provides a major route for intestinal Na+ absorption. It has been considered as a target of proinflammatory cytokines and enteropathogenic bacteria and impaired NHE3 expression and/or activity may be responsible for inflammation-associated diarrhea.
Colonic gene expression profile in NHE3-deficient mice: evidence for spontaneous distal colitis.
No sample metadata fields
View SamplesOsteoarthritis is characterized by degeneration of cartilage and bone in the synovial joints. Recent findings suggest that inflammation may play a role in osteoarthritis, with synovitis being associated with the clinical symptoms of osteoarthritis. Furthermore, we have found that levels of inflammatory complement components are abnormally high in the synovial fluid of individuals with osteoarthritis.
Identification of a central role for complement in osteoarthritis.
Sex, Age, Specimen part
View SamplesMSL (Male-specific lethal) complex increases transcription on the single X chromosome of Drosophila males in order to equalize expression of X-linked genes between males (XY) and females (XX). The increase in transcript levels correlates with MSL- dependent acetylation of histone H4 at K16 within the bodies of active genes, but identification of the transcriptional step affected has not been possible. In this study, we use global run-on sequencing (GRO-seq) to examine the specific effect of MSL complex on RNA Polymerase II (RNAP II) on a genome-wide level. Results indicate that MSL complex enhances transcription by facilitating the progression of RNAP II across the bodies of active X-linked genes. Improving transcriptional output downstream of typical gene-specific control may explain how dosage compensation can be imposed on the diverse set of genes along an entire chromosome. Overall design: Global Run-On Sequencing (GRO-Seq) reads, i.e., RNA-Seq of nascent RNA transcripts, from D. Melanogaster SL2 cells. Two biological replicates were analyzed.
Comprehensive analysis of the chromatin landscape in Drosophila melanogaster.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Depletion of DNMT1 in differentiated human cells highlights key classes of sensitive genes and an interplay with polycomb repression.
Sex, Specimen part, Time
View SamplesDNA methylation plays a vital role in the cell, but loss-of-function mutations of the maintenance methyltransferase DNMT1 in normal human cells are lethal, precluding target identification, and existing hypomorphic lines are tumour cells. We generated instead a hypomorphic series in normal hTERT-immortalised fibroblasts using stably integrated short hairpin RNA. Approx 2/3 of sites showed demethylation as expected, with 1/3 showing hypermethylation, and targets were shared between the three independently-derived lines. Enrichment analysis indicated significant losses at promoters and gene bodies with four gene classes most affected: 1)protocadherins, which are key to neural cell identity; 2)genes involved in fat homeostasis/body mass determination; 3)olfactory receptors and 4) cancer/testis antigen (CTA) genes. Overall effects on transcription were relatively small in these fibroblasts, but CTA genes showed robust derepression. Comparison with siRNA-treated cells indicated that shRNA lines show substantial remethylation over time. Regions showing persistent hypomethylation in the shRNA lines were associated with polycomb repression, and were derepressed on addition of an EZH2 inhibitor. Persistent hypermethylation in shRNA lines was in contrast associated with poised promoters. Our results suggest polycomb marking blocks remethylation and indicate the sensitivity of key neural, adipose, and cancer-associated genes to chronic depletion of maintenance methylation activity.
Depletion of DNMT1 in differentiated human cells highlights key classes of sensitive genes and an interplay with polycomb repression.
Sex, Specimen part, Time
View SamplesSynovial biopsies were obtained from osteoarthritis (OA) synovium to find genes upregulated during OA.
Functional Tissue Analysis Reveals Successful Cryopreservation of Human Osteoarthritic Synovium.
Specimen part, Disease, Disease stage
View SamplesAutism spectrum disorder (ASD) is an early onset neurodevelopmental disorder, which is characterized by disturbances of brain function and behavioral deficits in core areas of impaired reciprocal socialization, impairment in communication skills, and repetitive or restrictive interests and behaviors. ASD is known to have a significant genetic risk, but the underlying genetic variation can be attributed to hundreds of genes. The molecular and pathophysiologic basis of ASD remains elusive because of its genetic heterogeneity and complexity, its high comorbidity with other diseases, and the paucity of brain tissue for study. The invasive nature of collecting primary neuronal tissue from patients might be circumvented through reprogramming peripheral cells to induced pluripotent stem cells (iPSCs), which are able to generate live neurons carrying the genetic variants of disease. This breakthrough allows us to access the cellular and molecular phenotypes of patients with intrinsic autism, that is patients without known genetic disorders or identifiable syndromes or malformations. To do this, we studied a relatively homogeneous patient population of boys with intrinsic autism by excluding patients with known genetic disease or recognizable phenotypes or syndromes, as well as those with profound mental retardation or primary seizure disorders. We generated iPSCs from patients with intrinsic autism, their unaffected male siblings and age-, and sex-matched unaffected controls. And these stem cells were subsequently differentiated into electrophysiologically active neurons. The expression profile for autistic and their unaffected siblings' iPSC-derived neurons were compared. A distinct expression profile was found between autism and sib control. The significantly differentially expressed genes (> 2-fold, FDR < 0.05) in autistic iPSC-derived neurons were significantly enriched for processes related to synaptic transmission, such as neuroactive ligand-receptor signaling and extracellular matrix interactions (FDR < 0.05), and were significantly enriched for genes previously associated with ASD (p < 0.05). Our findings suggest approaches such as iPSC-derived neurons will be an important method to obtain tissue for study that appropriately recapitulates the complex dynamics of an autistic neural cell.
Idiopathic Autism: Cellular and Molecular Phenotypes in Pluripotent Stem Cell-Derived Neurons.
Specimen part, Cell line, Subject
View SamplesStem cells, with their potential to generate different lineages, could offer a solution by replacing damaged or lost cells within the inner ear. We have shown that human embryonic stem cells can be induced to differentiate into otic progenitors, and then into hair cell-like cells and neurons that display expected electrophysiological properties. More importantly, once these otic progenitors are transplanted into animals with induced hearing loss, they differentiate and elicit a significant recovery of auditory function. The generation of otic progenitors is triggered by FGF signalling. In this dataset we have analysed the global gene expression profile of undifferentiated hESCs and compared with cultures that have been treated with FGF3 and 10, the two ligands involved in otic induction, or cultures that have been allowed to differentiate under basal conditions without FGF (DFNB).
Restoration of auditory evoked responses by human ES-cell-derived otic progenitors.
Cell line, Treatment, Time
View Samples