A conserved molecular pathway has emerged controlling endoderm formation in Xenopus zebrafish and mice. Key genes in this pathway include Nodal ligands and transcription factors of the Mix-like paired homeodomain class, Gata4-6 zinc finger factors and Sox17 HMG domain proteins. While a linear epistatic pathway has been proposed, the precise hierarchical relationships between these factors and their downstream targets are largely unresolved. Here we used a combination of microarray analysis and loss-of-function experiments to examine the global regulatory network controlling Xenopus endoderm formation. We identified over 300 transcripts enriched in the gastrula endoderm, including most of the known endoderm regulators as well as over a hundred uncharacterized genes. Surprisingly only 10% of the endoderm transcriptome is regulated as predicted by the current linear model. We find that Nodals, Mixer and Sox17 have both shared and distinct sets of downstream targets and that a number of unexpected autoregulatory loops exist between Sox17 and Gata4-6, Sox17 and Bix1, 2, 4 and between Sox17 and Xnr4. We find that Mixer does not function primarily via Sox17 as previously proposed. This data provides a new insight into the complexity of endoderm formation and will serve as valuable resource for establishing a complete endoderm gene regulatory network.
Global analysis of the transcriptional network controlling Xenopus endoderm formation.
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View SamplesA persistent and non-resolving inflammatory response to accumulating A peptide species is a cardinal feature in the development of Alzheimer's disease (AD). In response to accumulating A peptide species, microglia, the innate immune cells of the brain, generate a toxic inflammatory response that accelerates synaptic and neuronal injury. Many pro-inflammatory signaling pathways are linked to progression of neurodegeneration. However, endogenous anti-inflammatory pathways capable of suppressing A-induced inflammation represent a relatively unexplored area.
Suppression of Alzheimer-associated inflammation by microglial prostaglandin-E2 EP4 receptor signaling.
Specimen part
View SamplesTissue-specific comparison of gene expression levels in T65H translocation mice, either with or without uniparental duplications of Chrs 7 & 11. Identification of highly differentially expressed transcripts.
Chromosome-wide identification of novel imprinted genes using microarrays and uniparental disomies.
Specimen part
View SamplesIn an acute skin wound, newly released serum growth factors in the wound bed drive lateral migration of human keratinocytes (HKs) to re-epithelialize the wound. However, profiling the migration signal-specific genes has long been challenged by pleiotropic effects of a given growth factor, including proliferation, migration and factor-specific responses. To overcome these technical problems, we 1) took advantage of a unique response of HKs to transforming growth factor-beta (TGFbeta) to selectively suppress growth signal-responding genes and identify motility-specific genes and 2) employed dual stimulation of HKs with TGFalpha and insulin to identify the common genes and eliminate factor-specific genes. Under these conditions, DNA microarray analyses were utilized to study the profiles of both TGFalpha-regualted and insulin-regulated immediate early (IE, 30 min), early (E, 60 min) and delayed early (DE, 120 min) genes.
Profiling motility signal-specific genes in primary human keratinocytes.
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View SamplesAbstract
Evidence of a functional role for mast cells in the development of type 1 diabetes mellitus in the BioBreeding rat.
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View SamplesComparison of gene expression levels between MatDp(dist2) and PatDp(dist2) mice (newborn whole head). Identification of highly differentially expressed transcripts.
Transcript- and tissue-specific imprinting of a tumour suppressor gene.
Specimen part
View SamplesThe complex milieu of inflammatory mediators associated with many diseases is often too dilute to directly measure in the periphery, necessitating development of more sensitive measurements suitable for mechanistic studies, earlier diagnosis, guiding selection of therapy, and monitoring interventions. Previously, we determined that plasma of recent-onset (RO) Type 1 diabetes (T1D) patients induce a proinflammatory transcriptional signature in fresh peripheral blood mononuclear cells (PBMC) relative to that of unrelated healthy controls (HC). Here, using an optimized cryopreserved PBMC-based protocol, we analyzed larger RO T1D, HC, and healthy T1D sibling cohorts. In addition, we examined T1D progression by looking at longitudinal samples.
Molecular signatures differentiate immune states in type 1 diabetic families.
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View SamplesNSAIDs (non-steroidal anti-inflammatory drugs) inhibit cyclooxygenase (COX) enzymes and prevent Alzheimers disease (AD) at preclinical stages in cognitively normal aging populations. We modeled NSAID prevention of memory impairment in AD model mice to identify novel targets of NSAID action.
Cyclooxygenase inhibition targets neurons to prevent early behavioural decline in Alzheimer's disease model mice.
Age, Specimen part, Treatment
View SamplesConsider the problem of designing a panel of complex biomarkers to predict a patient's health or disease state when one can pair his or her current test sample, called a target sample, with the patient's previously acquired healthy sample, called a reference sample. As contrasted to a population averaged reference, this reference sample is individualized. Automated predictor algorithms that compare and contrast the paired samples to each other could result in a new generation of test panels that compare to a person's healthy reference to enhance predictive accuracy. This study develops such an individualized predictor and illustrates the added value of including the healthy reference for design of predictive gene expression panels. The objective is to predict each subject's state of infection, e.g., neither exposed nor infected, exposed but not infected, pre-acute phase of infection, acute phase of infection, post-acute phase of infection. Using gene microarray data collected in a large-scale serially sampled respiratory virus challenge study, we quantify the diagnostic advantage of pairing a person's baseline reference with his or her target sample.
An individualized predictor of health and disease using paired reference and target samples.
Specimen part, Subject, Time
View SamplesArabidopsis fc2-1 mutants fail to properly de-etiolate after a prolonged period in the dark. Our goal was to monitor whole genome expression during the first 2 hours of de-etiolation to determine the cuase of this growth arrest.
Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts.
Specimen part
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