The root epidermis of Arabidopsis provides a simple and experimentally useful model for studying the molecular basis of cell fate and differentiation. The goal of this study was to define the larger gene regulatory network that governs the differentiation of the root hair and non-hair cell types of the Arabidopsis root epidermis. Transcript levels in the root epidermis of wild-type and mutant lines were assessed by purifying populations of root epidermal cells using fluorescence-based cell-sorting. Further, the role of the plant hormones auxin and ethylene on root epidermis development was assessed by defining transcript levels in the root epidermis of plants grown on media containing IAA or ACC. These microarray results were used to construct a comprehensive gene regulatory network that depicts the transcriptional control of root epidermal cell fate and differentiation in Arabidopsis.
A gene regulatory network for root epidermis cell differentiation in Arabidopsis.
Specimen part
View SamplesIn most embryos, the mid-blastula transition is a complex process featuring maternal RNA degradation, cell cycle pause, zygotic transcriptional activation and morphological changes. The nucleocytoplasmic (N/C) ratio has been proposed to control the multiple events at MBT. To understand the global transcriptional response to the changes of the N/C ratio, we profiled wild type and haploid embryos using cDNA microarrays at three developmental stages.
Coupling of zygotic transcription to mitotic control at the Drosophila mid-blastula transition.
No sample metadata fields
View SamplesKaposis sarcoma-associated hepesvirus (KSHV) encodes four genes with homology to human interferon regulatory factors (IRFs). One of these IRFs, the viral interferon regulatory factor 3 (vIRF-3) is expressed in latently infected PEL cells and required for their continuous proliferation. Moreover, vIRF-3 is known to be involved in modulation of the type I interferon response.
Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor 3 inhibits gamma interferon and major histocompatibility complex class II expression.
Specimen part, Cell line
View SamplesThe Early Growth Response (Egr) family of transcription factors consists of 4 members (Egr1-4) that are expressed in a wide variety of cell types. A large body of evidence point to a role for Egr transcription factors in growth, survival, and differentiation. A major unanswered question is whether Egr transcription factors serve similar functions in diverse cell types by activating a common set of target genes. Signal transduction cascades in neurons and lymphocytes show striking parallels. Activation of either cell type activates the Ras-MAPK pathway and, in parallel, leads to increases in intracellular calcium stimulating the calcineurin-NFAT pathway. In both cell types, the strength of the activation signal affects the cellular outcomes and very strong stimuli lead to cell death. Notably both these pathways converge on the induction of Egr genes. We believe that downstream targets of Egr transcription factors in lymphocytes may also be activated by Egr factors in activated neurons. There is precedence for common target gene activation in these two cell types: apoptosis in both activated T cells and methamphetamine stimulated neurons occurs via FasL induction by NFAT transcription factors. We propose to use developing T lymphocytes (thymocytes) as a model system for discovery of Egr-dependent target genes for several reasons. First, we have observed a prominent survival defect in thymocytes from mice deficient in both Egr1 and Egr3 (1/3 DKO) and a partial differention block in the immature double negative (DN) stage. In addition, thymocytes are an easily manipulatable cell type, and the DN subpopulation affected in 1/3 DKO mice can be isolated to very high purity. We anticipate that 1/3 DKO thymocytes will provide an excellent experimental system that will provide insight into Egr-dependent transcription in neuronal development, activation, and death.
Redundant role for early growth response transcriptional regulators in thymocyte differentiation and survival.
No sample metadata fields
View SamplesMice with the two calcium-stmulated adenylyl cyclase isoforms (AC1 and AC8; DKO mice) knocked-out show conditioned fear memory deficits. We assessed gene expression changes at baseline and several time points after conditioned fear learning to assess transcriptional changes at different stages of learning. Transcriptional changes were assessed in the amydgdala and hippocampus of DKO and wild-type mice.
Temporal and regional regulation of gene expression by calcium-stimulated adenylyl cyclase activity during fear memory.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Plasmacytoid dendritic cells and C1q differentially regulate inflammatory gene induction by lupus immune complexes.
Specimen part, Treatment, Subject
View SamplesThe goal of this study was to determine what genes are up- and down-regulated in response to lupus immune complexes in purified CD14+ monocyte stimulations. Our results have shown that novel genes are induced by immune complexes but the response is less robust when using purified monocytes versus total PBMCs
Plasmacytoid dendritic cells and C1q differentially regulate inflammatory gene induction by lupus immune complexes.
Specimen part, Treatment, Subject
View SamplesWe demonstrate for the first time that the extracellular matrix glycoprotein Tenascin-C regulates the expression of key patterning genes during late embryonic spinal cord development, leading to a timely maturation of gliogenic neural precursor cells. We first show that Tenascin-C is expressed by gliogenic neural precursor cells during late embryonic development. The loss of Tenascin-C leads to a sustained generation and delayed migration of Fibroblast growth factor receptor 3 expressing immature astrocytes in vivo. Furthermore, we could demonstrate an upregulation of Nk2 transcription factor related locus 2 (Nkx2.2) and its downstream target Sulfatase 1 in vivo. A dorsal expansion of Nkx2.2-positive cells within the ventral spinal cord indicates a potential progenitor cell domain shift. Moreover, Sulfatase 1 is known to regulate growth factor signalling by cleaving sulphate residues from heparan sulphate proteoglycans. Consistent with this possibility we observed changes in both Fibroblast growth factor 2 and Epidermal growth factor responsiveness of spinal cord neural precursor cells. Taken together our data clearly show that Tenascin-C promotes the astroglial lineage progression during spinal cord development.
The extracellular matrix molecule tenascin C modulates expression levels and territories of key patterning genes during spinal cord astrocyte specification.
Specimen part
View SamplesNine accessions of Arabidopsis were sampled before and after 14d of cold acclimation at 4°C. Transcript data were combined with metabolite data and related to quantitative measurement of plant freezing tolerance as determined by leaf electrolyte leakage assays.
Natural genetic variation of freezing tolerance in Arabidopsis.
Specimen part
View SamplesFamilial hypertrophic cardiomyopathy (FHC) is a disease characterized by ventricular hypertrophy, fibrosis, and aberrant systolic and/or diastolic function. Our laboratories have previously developed 2 mouse models that affect cardiac performance. One transgenic mouse model encodes an FHC-associated mutation in -tropomyosin (Tm180) that displays severe cardiac hypertrophy with fibrosis and impaired physiological performance. The other model was a gene knockout of phospholamban (PLB), a regulator of calcium uptake in the sarcoplasmic reticulum of cardiomyocytes; the hearts of these mice exhibit hypercontractility with no pathological abnormalities. Previous work in our laboratories show that the hearts of mice that were genetically crossed between the Tm180 and PLB KO mice rescues the hypertrophic phenotype and improves their cardiac morphology and function.
Microarray analysis of active cardiac remodeling genes in a familial hypertrophic cardiomyopathy mouse model rescued by a phospholamban knockout.
Age, Specimen part
View Samples