We examined the kinetics of production of mRNAs and small RNAs derived from transposable elements during mouse spermatogenesis, in whole gonads of wildtype and DNA methylation-deficient males (Dnmt3L and Miwi2 mutants). We found that in absence of DNA methylation, transposon reactivation is not constitutive but rather occurs in a class- and development-specific manner : both the intensity of reactivation and the number of reactivated transposon classes increased as germ cells progress in meiosis. Moreover, we observed that transposon silencing before meiosis is not due to increased cleavage by the piRNA machinery. In contrast, the burst of transposon transcripts occurring at meiosis in the absence of DNA methylation serve as substrates for increased piRNA production Overall design: Six whole testis samples were analyzed, corresponding to three time points (16.5dpc, 10dpp and 20dpp) each for Dnamt3L-/- animals and control littermates. For 16.5dpc, testes from 7/8 mice were pooled per genotype. For the other stages, three mice were pooled per genotype.
DNA methylation restrains transposons from adopting a chromatin signature permissive for meiotic recombination.
No sample metadata fields
View SamplesAlterations of chromatin modifiers are frequent in cancer but their functional consequences remain often unclear. Focusing on the Polycomb protein EZH2 that deposits H3K27me3 mark, we showed that its high expression in solid tumors is a consequence, and not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process is malfunctioning in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes are actually of poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes consequent to EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesPolycomb Repressive Complex 2 (PRC2) plays a key role in controlling transcriptional repression. It is thought to act at the level of the chromatin, where its enzymatic subunits Ezh1 and Ezh2 catalyse the di/tri-methylation of histone H3 on its lysine 27 (H3K27me3).
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesCellular stress responses can be activated following functional defects in organelles such as mitochondria and the endoplasmic reticulum. Mitochondrial dysfunction caused by loss of the serine protease HtrA2 leads to a progressive movement disorder in mice and has been linked to parkinsonian neurodegeneration in humans. Here we demonstrate that loss of HtrA2 results in transcriptional up-regulation of nuclear genes characteristic of the integrated stress response, including the transcription factor CHOP, selectively in the brain. We also show that loss of HtrA2 results in the accumulation of unfolded proteins in the mitochondria, defective mitochondrial respiration and enhanced production of reactive oxygen species that contribute to the induction of CHOP expression and to neuronal cell death. CHOP expression is also significantly increased in Parkinsons disease patients brain tissue. We therefore propose that this brain-specific transcriptional response to stress may be important in the advance of neurodegenerative diseases.
Mitochondrial dysfunction triggered by loss of HtrA2 results in the activation of a brain-specific transcriptional stress response.
No sample metadata fields
View SamplesCellular stress responses can be activated following functional defects in organelles such as mitochondria and the endoplasmic reticulum. Mitochondrial dysfunction caused by loss of the serine protease HtrA2 leads to a progressive movement disorder in mice and has been linked to parkinsonian neurodegeneration in humans. Here we demonstrate that loss of HtrA2 results in transcriptional up-regulation of nuclear genes characteristic of the integrated stress response, including the transcription factor CHOP, selectively in the brain. We also show that loss of HtrA2 results in the accumulation of unfolded proteins in the mitochondria, defective mitochondrial respiration and enhanced production of reactive oxygen species that contribute to the induction of CHOP expression and to neuronal cell death. CHOP expression is also significantly increased in Parkinsons disease patients brain tissue. We therefore propose that this brain-specific transcriptional response to stress may be important in the advance of neurodegenerative diseases.
Mitochondrial dysfunction triggered by loss of HtrA2 results in the activation of a brain-specific transcriptional stress response.
No sample metadata fields
View SamplesCellular stress responses can be activated following functional defects in organelles such as mitochondria and the endoplasmic reticulum. Mitochondrial dysfunction caused by loss of the serine protease HtrA2 leads to a progressive movement disorder in mice and has been linked to parkinsonian neurodegeneration in humans. Here we demonstrate that loss of HtrA2 results in transcriptional up-regulation of nuclear genes characteristic of the integrated stress response, including the transcription factor CHOP, selectively in the brain. We also show that loss of HtrA2 results in the accumulation of unfolded proteins in the mitochondria, defective mitochondrial respiration and enhanced production of reactive oxygen species that contribute to the induction of CHOP expression and to neuronal cell death. CHOP expression is also significantly increased in Parkinsons disease patients brain tissue. We therefore propose that this brain-specific transcriptional response to stress may be important in the advance of neurodegenerative diseases.
Mitochondrial dysfunction triggered by loss of HtrA2 results in the activation of a brain-specific transcriptional stress response.
No sample metadata fields
View SamplesLysosome-related organelles have versatile functions including protein and lipid degradation, signal transduction, and protein secretion. The molecular elucidation of rare congenital diseases affecting endosomal/lysosomal biogenesis has given insights into physiological functions of the innate and adaptive immune system.. Here, we describe a novel human primary immunodeficiency disorder and provide evidence that the endosomal adaptor protein p14, previously characterized as confining mitogen-activated-protein-kinase (MAPK) signaling to late endosomes, is critical for the function of neutrophils, B-cells, cytotoxic T-cells and melanocytes. Combining genetic linkage studies and transcriptional profiling analysis, we identified a homozygous point mutation in the 3 UTR of p14 (also known as MAPBPIP), resulting in decreased protein expression. In p14-deficient cells, the distribution of late endosomes was severely perturbed, suggesting a novel role for p14 in endosomal biogenesis. These findings have implications for understanding endosomal membrane dynamics, compartmentalization of cell signal cascades, and their role in immunity.
A novel human primary immunodeficiency syndrome caused by deficiency of the endosomal adaptor protein p14.
Specimen part
View SamplesBriefly, the well characterized female hES cell line H9 was allowed to differentiate into a clonally purified mortal splanchnopleuric mesodermal somatic cell line EN13. The EN13 line was subsequently virally reprogrammed back to an induced pluripotent state (we term re-H9) using OCT4, SOX2, KLF4 retroviral vectors creating isogenic lines of hESC, hiPSC and mortal cells. Our results reveal several important differences between embryo-derived H9 and the induced re-H9 stem cells. We find a dysregulation of genes involved in imprinting and altered expression of X-chromosome localized genes in re-H9 cells.
Suppression of the imprinted gene NNAT and X-chromosome gene activation in isogenic human iPS cells.
Cell line
View SamplesWe performed RNAseq on l(3)mbt mutant somatic ovaries to gain a genome-wide view of tissue-specific gene expression changes in L(3)mbt-depleted somatic ovaries. Overall design: Examination of gene expression changes in mutant and control somatic ovaries.
L(3)mbt and the LINT complex safeguard cellular identity in the <i>Drosophila</i> ovary.
Specimen part, Subject
View SamplesThese samples have been analyzed for global alternative splicing variation on exon-level expression data using the FIRMA algorithm. We have identified and described transcriptome instability as a genome-wide, pre-mRNA splicing related characteristic of solid cancers.
Transcriptome instability as a molecular pan-cancer characteristic of carcinomas.
Specimen part
View Samples