Post-translational modifications (PTMs) of histones exert fundamental roles in regulating gene expression. During development, groups of PTMs are constrained by unknown mechanisms into combinatorial patterns, which facilitate transitions from uncommitted embryonic cells into differentiated somatic cell lineages. Repressive histone modifications such as H3K9me3 or H3K27me3 have been investigated in detail, but the role of H4K20me3 in development is currently unknown. Here we show that Xenopus laevis Suv4-20h1 and h2 histone methyltransferases (HMTases) are essential for induction and differentiation of the neuroectoderm. Morpholino-mediated knockdown of the two HMTases leads to a selective and specific downregulation of genes controlling neural induction, thereby effectively blocking differentiation of the neuroectoderm. Global transcriptome analysis supports the notion that these effects arise from the transcriptional deregulation of specific genes rather than widespread, pleiotropic effects. Interestingly, morphant embryos fail to repress the Oct4-related Xenopus gene Oct-25. We validate Oct-25 as direct target of xSu4-20h enzyme-mediated gene repression, showing by chromatin immunoprecipitaton that it is decorated with the H4K20me3 mark downstream of the promoter in normal, but not in double-morphant, embryos. Since knockdown of Oct-25 protein significantly rescues the neural differentiation defect in xSuv4-20h double-morphant embryos, we conclude that the epistatic relationship between Suv4- 20h enzymes and Oct-25 controls the transit from pluripotent to differentiation-competent neural cells. Consistent with these results in Xenopus, murine Suv4-20h1/h2 double-knockout embryonic stem (DKO ES) cells exhibit increased Oct4 protein levels before and during EB formation, and reveal a compromised and biased capacity for in vitro differentiation, when compared to normal ES cells. Together, these results suggest a regulatory mechanism, conserved between amphibian and mammals, in which H4K20me3-dependent restriction of specific POU-V genes directs cell fate decisions, when embryonic cells exit the pluripotent state.
Suv4-20h histone methyltransferases promote neuroectodermal differentiation by silencing the pluripotency-associated Oct-25 gene.
Specimen part, Treatment
View SamplesIn order to understand if early epigenetic mechanisms instruct the long-term behaviour of neural stem cells (NSCs) and their progeny, we examined the protein Uhrf1 as it is highly expressed in NSCs of the developing brain and rapidly downregulated upon differentiation. Conditional deletion of Uhrf1 in the developing cerebral cortex resulted in rather normal proliferation and neurogenesis but severe postnatal neurodegeneration. During development, deletion of Uhrf1 resulted in global DNA hypomethylation with a strong activation of the IAP family of endogenous retroviral elements, accompanied by an increase in hydroxy methyl cytosine. Downregulation of Tet enzymes rescued the IAP activation in Uhrf1 cKO cells, suggesting an antagonistic interplay between Uhrf1 and Tet on IAP regulation. As IAP upregulation persists into postnatal stages in the conditional Uhrf1 KO mice, our data show the lack of means to repress IAPs in differentiating neurons that normally never express Uhrf1. The high load of viral proteins and other transcriptional dysregulation ultimately lead to extensive postnatal neurodegeneration. Taken together, these data show that early developmental NSC factors can have long-term effects in neuronal differentiation and survival. Moreover, it highlights how specific the consequences of widespread changes in DNA methylation are for certain classes of retroviral elements. Overall design: Transcriptome analysis in control vs. Uhrf1-deficient brain
Loss of Uhrf1 in neural stem cells leads to activation of retroviral elements and delayed neurodegeneration.
Specimen part, Cell line, Subject
View SamplesIn order to understand if early epigenetic mechanisms instruct the long-term behaviour of neural stem cells (NSCs) and their progeny, we examined the protein Uhrf1 as it is highly expressed in NSCs of the developing brain and rapidly downregulated upon differentiation. Conditional deletion of Uhrf1 in the developing cerebral cortex resulted in rather normal proliferation and neurogenesis but severe postnatal neurodegeneration. During development, deletion of Uhrf1 resulted in global DNA hypomethylation with a strong activation of the IAP family of endogenous retroviral elements, accompanied by an increase in hydroxy methyl cytosine. Downregulation of Tet enzymes rescued the IAP activation in Uhrf1 cKO cells, suggesting an antagonistic interplay between Uhrf1 and Tet on IAP regulation. As IAP upregulation persists into postnatal stages in the conditional Uhrf1 KO mice, our data show the lack of means to repress IAPs in differentiating neurons that normally never express Uhrf1. The high load of viral proteins and other transcriptional dysregulation ultimately lead to extensive postnatal neurodegeneration. Taken together, these data show that early developmental NSC factors can have long-term effects in neuronal differentiation and survival. Moreover, it highlights how specific the consequences of widespread changes in DNA methylation are for certain classes of retroviral elements. Overall design: Transcriptome analysis in control vs. Uhrf1-deficient brain
Loss of Uhrf1 in neural stem cells leads to activation of retroviral elements and delayed neurodegeneration.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Translational regulation of specific mRNAs controls feedback inhibition and survival during macrophage activation.
Specimen part, Time
View SamplesWhen macrophages encounter pathogens, they transiently induce an orchestrated cascade of pro- and anti-inflammatory genes. We systematically analyzed the contribution of translational regulation to the early phase of macrophage activation. While the expression of most cytokines is regulated by changes in mRNA levels, de-repression of translation was found to permit expression of many feedback inhibitors of the inflammatory response. This includes NF-kB inhibitors (IkBd, IkBz, Nr4a1, Ier3), a p38 MAPK antagonist (Dusp1) and post-transcriptional suppressors of cytokine expression (TTP and Zc3h12a). Ier3 is tightly co-regulated with TNF at the level of mRNA abundance and translation. Macrophages lacking Ier3 show reduced survival upon activation, indicating that induction of Ier3 is required to protect macrophages from lipopolysaccharide-induced cell death. Our analysis reveals an important role of translational regulation in the resolution of inflammation and macrophage survival.
Translational regulation of specific mRNAs controls feedback inhibition and survival during macrophage activation.
Specimen part
View SamplesWhen macrophages encounter pathogens, they transiently induce an orchestrated cascade of pro- and anti-inflammatory genes. To obtain a precise picture of transcriptome-wide mRNA expression patterns, we performed RNA-Seq of total RNA at a high temporal resolution during the first two hours of macrophage activation. We systematically analyzed the contribution of translational regulation to the early phase of macrophage activation. While the expression of most cytokines is pre-dominanatly regulated by changes in mRNA levels, de-repression of translation was found to permit expression of many feedback inhibitors of the inflammatory response. Overall design: Expression profiles of LPS-treated Raw264.7 cells (0, 15, 30, 45, 60, 75, 90 and 120 min after stimulation) were generated by deep sequencing using Illumina HiSeq 2000.
Translational regulation of specific mRNAs controls feedback inhibition and survival during macrophage activation.
No sample metadata fields
View SamplesAnalysis of the expression profile of adult mice heterozygous for Pitx2 isoform C.
PITX2c is expressed in the adult left atrium, and reducing Pitx2c expression promotes atrial fibrillation inducibility and complex changes in gene expression.
Age, Specimen part
View SamplesWe analyzed gene expression profiles of IL-18 generated murine NK cells in comparison to unstimulated, freshly isolated splenic NK cells.
Immunoregulatory natural killer cells suppress autoimmunity by down-regulating antigen-specific CD8+ T cells in mice.
Specimen part, Treatment
View SamplesResistance to platinum-based chemotherapy is a clinical challenge in the treatment of ovarian cancer (OC) and limits survival. Therefore, innovative drugs against platinum-resistance are urgently needed. Our therapeutic concept is based on the conjugation of two chemotherapeutic compounds to a monotherapeutic pro-drug, which is taken up by cancer cells and cleaved into active cytostatic metabolites. Here, we explore the activity of the duplex-prodrug 5-FdU-ECyd, covalently linking 2''-deoxy-5-fluorouridine (5-FdU) and 3''-C-ethynylcytidine (ECyd), on platinum-resistant OC cells. RNA-Sequencing was used for characterization of 5-FdU-ECyd treated platinum-sensitive A2780 and isogenic platinum-resistant A2780cis. Overall design: Platinum-sensitive A2780 and platinum resistant-cells A2780cis were treated with 5-FdU-Ecyd for 6h and 12h, there are also 6h and 12h untreated controls, all groups are in triplicates
The conjugated antimetabolite 5-FdU-ECyd and its cellular and molecular effects on platinum-sensitive vs. -resistant ovarian cancer cells <i>in vitro</i>.
Cell line, Subject, Time
View SamplesAcetyltransferases and histone deacetylases regulate gene expression at the level of chromatin, mainly by affecting transcription. In this study, we report that hyperacetylation induced by inhibition of histone deacetylases (HDACs) causes massive degradation of mRNA. The effect is promoter-independent and affects poly-A mRNA globally. HDAC inhibition leads to the removal of poly-A tails from mRNAs through activation of the deadenylase CAF1a, which we find to be acetylated together with its activator BTG2 by the histone acetyl transferases (HATs) p300 and CBP. By mutation of critical lysine residues, we provide evidence that acetylation of CAF1a and BTG2 induces enhanced poly-A mRNA degradation. Our study reveals a fundamental mechanism by which cells coordinate epigenetic and transcriptional control of gene expression with posttranscriptional control of poly-A mRNA stability. In this experiment, HeLa cells were exposed to the HDAC inhibitor trichostatin A (TSA) for 16 hours, followed by treatment with actinomycin D. Total RNA was isolated after 0, 2, 4 and 6 hours, and analysed by RNA sequencing. The half-lives of 7431 RNAs were calculated after normalization to rRNA (18S + 28S) levels. The experiment shows that TSA treatment causes a general reduction of poly-A RNA stability, while replication-dependent histone mRNA stability is not affected. Overall design: RNA half-lives were measured in TSA-treated or untreated HeLa cells by RNA-Seq using Illumina HiSeq 2000.
Acetylation-Dependent Control of Global Poly(A) RNA Degradation by CBP/p300 and HDAC1/2.
No sample metadata fields
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