Calyx of Held giant presynaptic terminals in the medial nucleus of the trapezoid body of the auditory brainstem form axosomatic synapses that have advanced to one of the best-studied synaptic system of the mammalian brain. As the auditory system matures and adjusts to high fidelity synaptic transmission, the calyx undergoes extensive structural and functional changes: it is formed around postnatal day 3 (P3), achieves immature function until hearing onset around P10 and can be considered mature from P21 onwards. This setting provides the unique opportunity to examine the repertoire of genes driving synaptic structure and function.
Gene expression profile during functional maturation of a central mammalian synapse.
Specimen part
View SamplesExposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows, but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone.
Chronic exposure to arsenic in the drinking water alters the expression of immune response genes in mouse lung.
No sample metadata fields
View SamplesIndividual genetic variation affects gene expression and cell phenotype by acting within complex molecular circuits, but this relationship is still largely unknown. Here, we combine genomic and meso-scale profiling with novel computational methods to detect genetic variants that affect the responsiveness of gene expression to stimulus (responsiveness QTLs) and position them in circuit diagrams. We apply this approach to study individual variation in transcriptional responsiveness to three different pathogen components in the model response of primary bone marrow dendritic cells (DCs) from recombinant inbred mice strains. We show that reQTLs are common both in cis (affecting a single target gene) and in trans (pleiotropically affecting co-regulated gene modules) and are specific to some stimuli but not others. Leveraging the stimulus-specific activity of reQTLs and the differential responsiveness of their associated targets, we show how to position reQTLs within the context of known pathways in this regulatory circuit. For example, we find that a pleiotropic trans-acting genetic factor in chr1:129-165Mb affects the responsiveness of 35 anti-viral genes only during an anti-viral like stimulus. Using RNAi we uncover RGS16 the likely causal gene in this interval, and an activator of the antiviral response. Our approach charts an experimental and analytic path to decipher the mechanisms underlying genetic variation in other complex circuits in primary mammalian cells.
Deciphering molecular circuits from genetic variation underlying transcriptional responsiveness to stimuli.
Age, Specimen part
View SamplesWe sequenced mRNA from transverse slices of embryos from a variety of D. melanogaster mutants (bicoid over-expression, bicoid knockdown, hunchback knocdown, and zelda mutant) at the blastoderm stage to determine genome-wide patterns of gene expression. Overall design: mRNA from transverse sections of single D. melanogaster embryos mutant for patterning TFs was sequenced.
Genome-wide measurement of spatial expression in patterning mutants of <i>Drosophila melanogaster</i>.
Specimen part, Subject
View SamplesWe sequenced mRNA from transverse slices of embryos at the blastoderm stage to determine genome-wide patterns of gene expression. Overall design: mRNA from transverse sections of single D. melanogaster embryos was sequenced
Sequencing mRNA from cryo-sliced Drosophila embryos to determine genome-wide spatial patterns of gene expression.
Specimen part, Disease, Cell line, Subject
View SamplesWe sequenced mRNA according to several library prep protocols with known mixtures of two species of Drosophila in order to establish linear response in each protocol. Overall design: For each library prep protocol, mixtures with 0%, 5%, 10%, and 20% D. virilis total RNA was prepared, then libraries prepared according to instructions.
Low-cost, low-input RNA-seq protocols perform nearly as well as high-input protocols.
Subject
View SamplesWe report that TAF3, a TBP-associated core promoter factor, is highly enriched in ES cells. In addition to its role in the core promoter recognition complex TFIID, genome-wide binding studies reveal that TAF3 localizes to chromosomal regions bound by CTCF and cohesin. Enrichment for TAF3/CTCF/cohesin bound regions distinguishes TAF3-activated from TAF3-repressed genes. Our findings support a new role of TAF3 in mediating long-range chromatin regulatory interactions to safeguard the finely-balanced transcriptional programs that give rise to pluripotency. Overall design: Comparison of genome-wide expression patterns between TAF3-knockdown and WT embryonic stem cells using mRNA-Seq. Significantly differentially expressed protein-coding genes were identified by comparing control and knock-down samples at each timepoint (ES, embryoid body day 3 (EB3), EB6). Single and paired-end samples were combined at each timepoint, resulting in 3 tests for each gene (based on 8, 4, 4 independent measurements at ES ,EB3, EB6, respectively).
Control of embryonic stem cell lineage commitment by core promoter factor, TAF3.
Specimen part, Cell line, Subject, Time
View SamplesWe examined the effects of TNFa and Spt5, the major DSIF subunit, on nascent and mature transcripts using RNA-Seq of chromatin-associated and cytoplasmic transcripts. Overall design: RNA was extracted from the cytosolic and chromatin fractions of control and Spt5 KD cells that were treated with TNFa for 1 hour
Analysis of Subcellular RNA Fractions Revealed a Transcription-Independent Effect of Tumor Necrosis Factor Alpha on Splicing, Mediated by Spt5.
No sample metadata fields
View SamplesThe Wnt signaling pathway plays a fundamental role during the development of metazoans, where it functions in the regulation of diverse processes including cell fate specification, cell migration, and stem cell renewal. Activation of the beta-catenin dependent or canonical Wnt signaling pathway upregulates expression of Wnt target genes to mediate an appropriate cellular response. In the nematode C. elegans, a Wnt signaling pathway similar to the canonical pathway regulates several processes during larval development, however few target genes of this pathway have been identified. To address this deficit, we conditionally activated Wnt signaling in living animals during a defined stage of larval life by expressing a dominant, activated beta-catenin protein, then used microarray analysis to identify genes showing altered expression compared to control animals. In this way we identified 166 differentially expressed genes, of which 104 were upregulated. A subset of the upregulated genes were validated by qPCR and showed altered expression in Wnt pathway mutants with decreased or increased Wnt signaling; we consider these genes to be candidate Wnt pathway targets in the C. elegans hermaphrodite larva. Amongst these was a group of 6 genes, including the cuticular collagen genes, bli-1 col-38, col-49 and col-71, that show a peak of expression in the mid L4 stage during normal development. The L4 expression of these genes suggests they may be expressed for use in the adult cuticle, and consistent with this, reduction of function for several of the genes leads to phenotypes suggestive of defects in cuticle function or integrity. Therefore this work has identified a large number of putative Wnt pathway target genes during larval life, including a small subset of Wnt-regulated collagen genes that may function in synthesis of the adult cuticle.
Use of an activated beta-catenin to identify Wnt pathway target genes in caenorhabditis elegans, including a subset of collagen genes expressed in late larval development.
No sample metadata fields
View SamplesWe introduced genome-wide pooled CRISPR-Cas9 libraries into primary mouse dendritic cells (DCs) to identify genes that control the induction of tumor necrosis factor (TNF) by bacterial lipopolysaccharide (LPS), a key process in the host response to pathogens, mediated by the TLR4 pathway. We found many of the known regulators of TLR4 signaling, as well as dozens of previously unknown candidates that we validated. Overall design: We used stain base phenotype (staining for TNF) in order to search for negative and positive regulators of LPS response in differentiated BMDCs
A Genome-wide CRISPR Screen in Primary Immune Cells to Dissect Regulatory Networks.
No sample metadata fields
View Samples