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GSE12205
Homo sapiens
10 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Although the consequences of genotoxic injury include cell cycle arrest and apoptosis, cell survival responses after genotoxic injury can produce intrinsic death-resistance and contribute to the development of a transformed phenotype. Protein tyrosine phosphatases (PTPs) are integral components of key survival pathways, and are responsible for their inactivation, while PTP inhibition is are often associated with enhanced cell proliferation. Our aim was to elucidate signaling events that modulate cell survival after genotoxin exposure. Diploid human lung fibroblasts (HLF) were treated with Cr(VI) (as Na2CrO4), a well known human respiratory carcinogen that induces a wide spectrum of DNA damage, in the presence and absence of a broad-range PTP inhibitor, sodium orthovanadate. Notably, PTP inhibition abrogated Cr(VI)-induced clonogenic lethality. The enhanced survival of Cr(VI)-exposed cells after PTP inhibition was predominantly due to a bypass of cell cycle arrest and was not due to decreased Cr uptake as evidenced by unchanged Cr-DNA adduct burden. Additionally, the bypass of Cr-induced growth arrest by PTP inhibition, was accompanied by a decrease in Cr(VI)-induced expression of cell cycle inhibiting genes, and an increase in the Cr(VI)-induced expression of cell cycle promoting genes. Importantly, PTP inhibition resulted in an increase in forward mutations at the HPRT locus, supporting the hypothesis that PTP inhibition in the presence of DNA damage may lead to genomic instability, via bypass of cell cycle checkpoints.
Publication Title
Bypass of hexavalent chromium-induced growth arrest by a protein tyrosine phosphatase inhibitor: enhanced survival and mutagenesis.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 72 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
A preliminary understanding of the phenotypic effect of copy number variation (CNV) of DNA segments is emerging. These rearrangements were demonstrated to influence, in a somewhat dose-dependent manner, the expression of genes mapping within. They were shown to also affect the expression of genes located on their flanks, sometimes at great distance. Here, we show by monitoring these effects at multiple life stages, that these controls over expression are effective throughout mouse development. Similarly, we observe that the more specific spatial expression patterns of CNV genes are maintained throughout life. However, we find that some brain-expressed genes appear to be under compensatory loops only at specific time-points, indicating that the influence of CNVs on these genes is modulated through development. We also observe that CNV genes are significantly enriched upon transcripts that show variable time-course of expression in different strains. Thus modifying the number of copy of a gene not only potentially alters its expression level, but possibly also its time of expression.
Publication Title
Copy number variation modifies expression time courses.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Mus musculus
- 61 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
To study the effect of structural changes on expression, we assessed gene expression in genomic disorder mouse models. Both a microdeletion and its reciprocal microduplication mapping to mouse chromosome 11 (MMU11), which model the rearrangements present in Smith-Magenis (SMS) and Potocki-Lupski (PTLS) syndromes patients, respectively, have been engineered. We profiled the transcriptome of five different tissues affected in human patients in mice with 1n (Deletion/+), 2n (+/+), 3n (Duplication/+) and uniallelic 2n (Deletion/Duplication) copies of the same region in an identical genetic background. The most differentially expressed transcripts between the four studied genotypes were ranked. A highly significant propensity, are mapping to the engineered SMS/PTLS interval in the different tissues. A statistically significant overrepresentation of the genes mapping to the flanks of the engineered interval was also found in the top-ranked differentially expressed genes. A phenomenon efficient across multiple cell lineages and that extends along the entire length of the chromosome, tens of megabases from the breakpoints. These long-range effects are unidirectional and uncoupled from the number of copies of the copy number variation (CNV) genes. Thus, our results suggest that the assortment of genes mapping to a chromosome is not random. They also indicate that a structural change at a given position of the human genome may cause the same perturbation in particular pathways regardless of gene dosage. An issue that should be considered in appreciating the contribution of this class of variation to phenotypic features.
Publication Title
Phenotypic consequences of copy number variation: insights from Smith-Magenis and Potocki-Lupski syndrome mouse models.
Sample Metadata Fields
Sex
View Samples- Mus musculus
- 35 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Through post-transcriptional regulation of gene expression, miRNAs affect numerous regulatory pathways including those crucial for maintaining metabolic balance. Here we demonstrate that a neuronal-specific inhibition of miRNA maturation in adult mice leads to a rapid development of severe obesity, which is equally rapidly reversed. Development of obesity was associated with increased food intake and efficiency, and decreased locomotor activity. The ensuing decrease in body weight resembled a catabolic state with lowered O2-consumption and respiratory-exchange ratio. Brain transcriptome analyses in obese mice identified several obesity-related pathways including leptin, somatostatin, and nemo-like kinase signaling, as well as genes involved in feeding and appetite (e.g. Pmch, Neurotensin). A cluster of genes involved in synaptic plasticity was specifically enriched in post-obese mice that did not appear in obese mice. While other studies have identified a role for miRNAs in obesity our model is unique in that it allows for the study of processes involved in reversing obesity.
Publication Title
A neuron-specific deletion of the microRNA-processing enzyme DICER induces severe but transient obesity in mice.
Sample Metadata Fields
Specimen part, Time
View Samples- Rattus norvegicus
- 32 Downloadable Samples
- Affymetrix Rat Gene 1.0 ST Array (ragene10st)
Description
Thymic epithelial cells (TECs) are essential for thymopoiesis and form a complex three-dimensional network, the organization of which is strikingly different from other epithelia. Interestingly, TECs express simple epithelia keratins in the cortex, stratified epithelia keratins in the medulla and epidermal differentiation markers in Hassall's bodies. Here we investigate the relationship between thymic epithelium and epidermal differentiation and show that the thymus of the rat contains a population of clonogenic TECs that can be extensively cultured and cloned using conditions developed for epidermal cell therapy in human. Clonogenic TECs conserve a thymic identity and the capacity to integrate in a thymic epithelial network, but they acquire new functionalities when exposed to an inductive skin microenvironment, permanently adopting the fate of hair follicle multipotent stem cells. This change in fate, maintained over time in serial transplantation, correlates with a down-regulation of transcription factors important for thymic identity, and an up-regulation of epidermal markers. Consequently, the TECs capacity to integrate in a thymic epithelial network is altered or even lost. Our results demonstrate that the thymus contains a population of holoclone-like epithelial cells that can function as bona fide multipotent keratinocyte stem cells, and that microenvironmental cues are sufficient to re-direct epithelial-cell fate, allowing crossing of primitive germ layer boundaries from endoderm to ectoderm.
Publication Title
Microenvironmental reprogramming of thymic epithelial cells to skin multipotent stem cells.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 24 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
The recently released Affymetrix Human Gene 1.0 ST array has two major differences compared with standard 3' based arrays: (1) it interrogates the entire mRNA transcript, and (2) it uses cDNA targets. To assess the impact of these differences on array performance, we performed series of comparative hybridizations between the Human Gene 1.0 ST and the Affymetrix HG-U133 Plus 2.0 and the Illumina HumanRef-8 BeadChip arrays. Additionally, both cRNA and cDNA targets were probed on the HG-U133 Plus 2.0 array. The results show that the overall reproducibility is best using the Gene 1.0 ST array. When looking only at the high intensity probes, the reproducibility of the Gene 1.0 ST array and the Illumina BeadChip array is equally good. Concordance of array results was assessed using different inter-platform mappings. The Gene 1.0 ST is most concordant with the HG-U133 array hybridized with cDNA targets, thus showing the impact of the target type. Agreements are better between platforms with designs which choose probes from the 3' end of the gene. Overall, the high degree of correspondence provides strong evidence for the reliability of the Gene 1.0 ST array.
Publication Title
Affymetrix Whole-Transcript Human Gene 1.0 ST array is highly concordant with standard 3' expression arrays.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 24 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Renal excretion of water and major electrolytes exhibits a significant circadian rhythm. This functional periodicity is believed to result, at least in part, from circadian changes in secretion/reabsorption capacities of the distal nephron and collecting ducts. Here, we studied the molecular mechanisms underlying circadian rhythms in the distal nephron segments, i.e. distal convoluted tubule (DCT) and connecting tubule (CNT) and, the cortical collecting duct (CCD). Temporal expression analysis performed on microdissected mouse DCT/CNT or CCD revealed a marked circadian rhythmicity in the expression of a large number of genes crucially involved in various homeostatic functions of the kidney. This analysis also revealed that both DCT/CNT and CCD possess an intrinsic circadian timing system characterized by robust oscillations in the expression of circadian core clock genes (clock, bma11, npas2, per, cry, nr1d1) and clock-controlled Par bZip transcriptional factors dbp, hlf and tef. The clock knockout mice or mice devoid of dbp/hlf/tef (triple knockout) exhibit significant changes in renal expression of several key regulators of water or sodium balance (vasopressin V2 receptor, aquaporin-2, aquaporin-4, alphaENaC). Functionally, the loss of clock leads to a complex phenotype characterized by partial diabetes insipidus, dysregulation of sodium excretion rhythms and a significant decrease in blood pressure. Collectively, this study uncovers a major role of molecular clock in renal function.
Publication Title
Molecular clock is involved in predictive circadian adjustment of renal function.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 24 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Most metabolic studies are conducted in male animals; thus, the molecular mechanism controlling gender-specific pathways has been neglected, including sex-dependent responses to peroxisome proliferator-activated receptors (PPARs). Here we show that PPARalpha has broad female-dependent repressive actions on hepatic genes involved in steroid metabolism and inflammation. In males, this effect is reproduced by the administration of synthetic PPARalpha ligand. Using the steroid hydroxylase gene Cyp7b1 as a model, we elucidated the molecular mechanism of this PPARalpha-dependent repression. Initial sumoylation of the ligand-binding domain of PPARalpha triggers the interaction of PPARalpha with the GA-binding protein alpha bound to the target promoter. Histone deacetylase is then recruited, and histones and adjacent Sp1-binding site are methylated. These events result in the loss of Sp1-stimulated expression, and thus the down-regulation of Cyp7b1. Physiologically, this repression confers protection against estrogen-induced intrahepatic cholestasis, paving the way for a novel therapy against the most common hepatic disease during pregnancy.
Publication Title
Sumoylated PPARalpha mediates sex-specific gene repression and protects the liver from estrogen-induced toxicity in mice.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 22 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Recent evidence suggest that the circadian timing system plays an important role in the control of renal function and maintaining blood pressure. Here, we analyzed circadian rhythms of urinary excretion of sodium and potassium in wild-type mice and mice lacking circadian transcriptional activator clock. Analysis of urines collected at hourly intervals over a 24-hour period revealed dramatic changes in rhythms of sodium and potassium excretion in clock(-/-) mice. In parallel, significant differences in circadian pattern of plasma aldosterone levels, but not in the 24-hour mean aldosterone levels, were observed. Microarray-based profiling of renal transcriptomes demonstrated that clock(-/-) mice exhibit dysregulation in multiple mechanisms involved in maintaining sodium and potassium balance by the kidney. The most significant changes were detected in the expression levels of several key enzymes (Cyp4a14, Cyp4a12a and Cyp4a12b) required for the conversion of arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), a powerful regulator of renal sodium and potassium excretion, renal vascular tone and blood pressure. The 20-HETE levels measured in kidney microsomes of wild-type mice followed a circadian-like temporal pattern. In clock(-/-) mice, the acrophase of this rhythm was shifted by 8 hours and the 24-hour mean levels of 20-HETE were significantly decreased. These results demonstrate that circadian rhythms of urine electrolyte excretion are largely dependent on the circadian clock activity and indicate that circadian oscillations in renal 20-HETE content could be an important mechanism of blood pressure regulation.
Publication Title
No associated publication
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 18 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and attacks of muscle atonia triggered by strong emotions (cataplexy). The best biological marker of narcolepsy is orexin deficiency with dramatic loss in hypothalamic orexin-producing neurons. Together with a tight HLA and T-cell receptor alpha(5) association, narcolepsy is believed to be autoimmune although all attempts to prove it have failed.To characterize orexin specific peptides we produced a transgenic mouse model to access to the orexin neurons transcription profile. We generated BAC-based transgenic mice by replacing the orexin coding sequence by a flag-tagged poly(A) binding protein (Pabp1) cDNA sequence. The basis of this construct is to take advantage of the ability of Pabp1 to bind to the poly(A) tails of mRNAs in vivo. Thus mRNAs from orexin cells are expected to be enriched by cross-linking them to the flag-tagged PABP and then co-immunoprecipitating this complex with a specific anti-flag monoclonal antibody.
Publication Title
Elevated Tribbles homolog 2-specific antibody levels in narcolepsy patients.
Sample Metadata Fields
Age
View Samples