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.
Sumoylated PPARalpha mediates sex-specific gene repression and protects the liver from estrogen-induced toxicity in mice.
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View SamplesPhytochromes are red/far red photosensors regulating numerous developmental programs in plants. Among them phytochrome A (phyA) is essential to enable seedling de-etiolation in continuous far-red (FR) light a condition mimicking the environment under a dense canopy. The ecological relevance of this response is demonstrated by the high mortality rate of phyA mutants germinating in deep vegetational shade. phyA signaling involves a direct interaction of the photoreceptor with members of the bHLH transcription factor family, PIF1 and PIF3 (Phytochrome Interacting Factor). Here we investigated the involvement of PIF4 and PIF5 in phyA signaling and found that they redundantly control de-etiolation in FR light. The pif4pif5 double mutant is hypersensitive to low fluence rates of FR light. This phenotype is dependent on FR light perception by phyA but does not rely on alterations of the phyA level. Our microarrays analysis shows that PIF4 and PIF5 are part of an inhibitory mechanism repressing the expression of some light-responsive genes in the dark and are also needed for full expression of several growth-related genes in the light. Unlike PIF1 and PIF3, PIF4 and PIF5 are not degraded in response to FR light indicating that they are light-regulated by a different mechanism. Our genetic analysis suggests that this is achieved through the sequestration of these PIFs by the closely related bHLH transcription factor HFR1 (long Hypocotyl in FR light).
Phytochrome interacting factors 4 and 5 redundantly limit seedling de-etiolation in continuous far-red light.
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View SamplesA 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.
Copy number variation modifies expression time courses.
Sex, Age, Specimen part
View SamplesThrough 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.
A neuron-specific deletion of the microRNA-processing enzyme DICER induces severe but transient obesity in mice.
Specimen part, Time
View SamplesThe 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.
Affymetrix Whole-Transcript Human Gene 1.0 ST array is highly concordant with standard 3' expression arrays.
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View SamplesThe goal of this study was to determine if blood circulating monocytes of metastatic breast cancer patient would express a different activation profile compared to healthy donors, in order to use this specific changesas biomarkers to monitor then response to therapy Overall design: CD11b+ cells were extracted from all blood of 4 healthy donors and 4 metastatic breast cancer patients using magnetic beads separation (Miltenyi). CD11b+ cells were then lysed and mRNA was extracted to perform RNASeq.
Bevacizumab specifically decreases elevated levels of circulating KIT+CD11b+ cells and IL-10 in metastatic breast cancer patients.
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View SamplesRenal 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.
Molecular clock is involved in predictive circadian adjustment of renal function.
Sex, Specimen part
View SamplesCopy number variation (CNV) of DNA segments has recently been identified as a major source of genetic diversity, but a more comprehensive understanding of the extent and phenotypic effect of this type of variation is only beginning to emerge. In this study we generated genome-wide expression data from 6 mouse tissues to investigate how CNVs influence gene expression.
Segmental copy number variation shapes tissue transcriptomes.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Homer1a is a core brain molecular correlate of sleep loss.
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View SamplesThese studies adress differential changes in gene expression between sleep deprived and control mice. We profiled gene expression at four time points across the 24H Light/Dark cycle to take into account circadian influences and used three different inbred strains to understand the influence of genetic background.
Homer1a is a core brain molecular correlate of sleep loss.
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