Similar Datasets
Project description:The non-proteolytic role of the proteasome in heterochromatin regulation
2018-02-16 | GSE97865 | GEO
Project description:It is important to accurately regulate the expression of genes involved in development and environmental response. In the fission yeast Schizosaccharomyces pombe, meiotic genes are tightly repressed during vegetative growth. Despite being embedded in heterochromatin these genes are transcribed and believed to be repressed primarily at the level of RNA. However, the mechanism of facultative heterochromatin formation and the interplay with transcription regulation is not understood. We show genome-wide that HDAC-dependent histone deacetylation is a major determinant in transcriptional silencing of facultative heterochromatin domains. Indeed, mutation of class I/II HDACs leads to increased transcription of meiotic genes and accumulation of their mRNAs. Mechanistic dissection of the pho1 gene where, in response to phosphate, transient facultative heterochromatin is established by overlapping lncRNA transcription shows that the Clr3 HDAC contributes to silencing independently of SHREC, but in an lncRNA-dependent manner. We propose that HDACs promote facultative heterochromatin by establishing alternative transcriptional silencing.
2018-03-19 | GSE108668 | GEO
Project description: Not available
| S-EPMC6009587 | biostudies-literature
Project description:Epe1 histone demethylase restricts H3K9-methylation-dependent heterochromatin, preventing it from spreading over, and silencing, gene-containing regions in fission yeast. External stress induces an adaptive response allowing heterochromatin island formation that confers resistance on surviving wild-type lineages. Here we investigate the mechanism by which Epe1 is regulated in response to stress. Exposure to caffeine or antifungals results in Epe1 ubiquitylation and proteasome-dependent removal of the N-terminal 150 residues from Epe1, generating truncated tEpe1 which accumulates in the cytoplasm. Constitutive tEpe1 expression increases H3K9 methylation over several chromosomal regions, reducing expression of underlying genes and enhancing resistance. Reciprocally, constitutive non-cleavable Epe1 expression decreases resistance. tEpe1-mediated resistance requires a functional JmjC demethylase domain. Moreover, caffeine-induced Epe1-to-tEpe1 cleavage is dependent on an intact cell-integrity MAP kinase stress signalling pathway, mutations in which alter resistance. Thus, environmental changes provoke a mechanism that curtails the function of this key epigenetic modifier, allowing heterochromatin to reprogram gene expression, thereby bestowing resistance to some cells within a population. H3K9me-heterochromatin components are conserved in human and crop plant fungal pathogens for which a limited number of antifungals exist. Our findings reveal how transient heterochromatin-dependent antifungal resistant epimutations develop and thus inform on how they might be countered.
2022-10-13 | PXD030205 | Pride
Project description:Epe1 histone demethylase restricts H3K9-methylation-dependent heterochromatin, preventing it from spreading over, and silencing, gene-containing regions in fission yeast. External stress induces an adaptive response allowing heterochromatin island formation that confers resistance on surviving wild-type lineages. Here we investigate the mechanism by which Epe1 is regulated in response to stress. Exposure to caffeine or antifungals results in Epe1 ubiquitylation and proteasome-dependent removal of the N-terminal 150 residues from Epe1, generating truncated tEpe1 which accumulates in the cytoplasm. Constitutive tEpe1 expression increases H3K9 methylation over several chromosomal regions, reducing expression of underlying genes and enhancing resistance. Reciprocally, constitutive non-cleavable Epe1 expression decreases resistance. tEpe1-mediated resistance requires a functional JmjC demethylase domain. Moreover, caffeine-induced Epe1-to-tEpe1 cleavage is dependent on an intact cell-integrity MAP kinase stress signalling pathway, mutations in which alter resistance. Thus, environmental changes provoke a mechanism that curtails the function of this key epigenetic modifier, allowing heterochromatin to reprogram gene expression, thereby bestowing resistance to some cells within a population. H3K9me-heterochromatin components are conserved in human and crop plant fungal pathogens for which a limited number of antifungals exist. Our findings reveal how transient heterochromatin-dependent antifungal resistant epimutations develop and thus inform on how they might be countered.
2022-05-04 | GSE190267 | GEO
Project description:Histone deacetylation promotes transcriptional silencing at facultative heterochromatin
| PRJNA428233 | ENA
Project description:The objective of this study is to identify the genes that are up-regulated amid proteasome dysfunction to facilitate the discovery of proteolytic pathways that are activated as a compensatory response to proteasome inhibition. Proteasome is a large multi-component proteolytic complex in the cell. It is responsible for the constitutive turn-over of many cellular proteins as well as the degradation of oxidized and/or unfolded proteins. With such a fundamental role in the cell, disruption of proteasome understandably can lead to disastrous outcome. Oxidative stress has been postulated as the driving mechanism for aging. Oxidatively modified proteins, which usually have lost their activity, require immediate removal by proteasome to maintain normal cellular function. Dysfunction of proteasome has also been linked to neuro-degenerative diseases such as Alzheimer?¢¬Ä¬ôs and Parkinson?¢¬Ä¬ôs diseases, those that are most commonly seen in aged population. There is more than one proteolytic pathway in the cell, and it has been reported that obstruction of any one of these pathways may enhance the activity of the others. Proteasomal function has been found to have decreased during aging, prompting researchers to hypothesize that failure to remove oxidized proteins may play an important role in aging. It would be interesting to determine the other proteolytic pathways that are activated after proteasome inhibition by a relatively specific inhibitor epoxomicin to help understand their roles in aging processes. Experiment Overall Design: Human embryonic kidney cells (HEK293) were untreated or treated with 1 uM epoxomicin for 1 and 6 hours. Total RNA was extracted for gene expression profiling using Affymetrix human genome U133 2.0 plus chip. A quadrupliate was prepared for each treatment. Experiment Overall Design: contributor: NHLBI Gene Expression Core Facility
2009-01-27 | E-GEOD-14429 | biostudies-arrayexpress
Project description:The objective of this study is to identify the genes that are up-regulated amid proteasome dysfunction to facilitate the discovery of proteolytic pathways that are activated as a compensatory response to proteasome inhibition. Proteasome is a large multi-component proteolytic complex in the cell. It is responsible for the constitutive turn-over of many cellular proteins as well as the degradation of oxidized and/or unfolded proteins. With such a fundamental role in the cell, disruption of proteasome understandably can lead to disastrous outcome. Oxidative stress has been postulated as the driving mechanism for aging. Oxidatively modified proteins, which usually have lost their activity, require immediate removal by proteasome to maintain normal cellular function. Dysfunction of proteasome has also been linked to neuro-degenerative diseases such as Alzheimer’s and Parkinson’s diseases, those that are most commonly seen in aged population. There is more than one proteolytic pathway in the cell, and it has been reported that obstruction of any one of these pathways may enhance the activity of the others. Proteasomal function has been found to have decreased during aging, prompting researchers to hypothesize that failure to remove oxidized proteins may play an important role in aging. It would be interesting to determine the other proteolytic pathways that are activated after proteasome inhibition by a relatively specific inhibitor epoxomicin to help understand their roles in aging processes. Keywords: time course, proteasome, inhibitor, oxidative stress, epoxomicin
2009-01-15 | GSE14429 | GEO
Project description:The proteasome can regulate transcription through proteolytic processing of transcription factors and via gene locus binding, but few targets of proteasomal regulation have been identified. Using genome-wide location analysis and transcriptional profiling in Saccharomyces cerevisiae, we have established which genes are bound and regulated by the proteasome, and by Spt23 and Mga2, transcription factors activated by the proteasome. We observed proteasome association with gene sets that are highly transcribed, controlled by the mating-type loci, and involved in lipid metabolism. At ribosomal protein genes, proteasome and RNA polymerase II binding was enriched in a proteasome mutant, indicating a role for the proteasome in dissociating elongation complexes. The genomic occupancies of Spt23 and Mga2 overlapped significantly with the genes bound by the proteasome. Finally, the proteasome acts in two distinct ways, one dependent and one independent of Spt23/Mga2 cleavage, providing evidence for cooperative gene regulation by the proteasome and its substrates. Keywords: ChIP-chip; genetic modification transcriptional profiling Six genomic localization analysis (GLA, ChIP2) experiments are represented by 18 samples. Six transcriptional profiling experiments (prof) are also represented. Experiments were generally done in triplicate, with fluors swapped on the third replicate.
2006-02-28 | E-GEOD-4272 | biostudies-arrayexpress
Project description:The proteasome can regulate transcription through proteolytic processing of transcription factors and via gene locus binding, but few targets of proteasomal regulation have been identified. Using genome-wide location analysis and transcriptional profiling in Saccharomyces cerevisiae, we have established which genes are bound and regulated by the proteasome, and by Spt23 and Mga2, transcription factors activated by the proteasome. We observed proteasome association with gene sets that are highly transcribed, controlled by the mating-type loci, and involved in lipid metabolism. At ribosomal protein genes, proteasome and RNA polymerase II binding was enriched in a proteasome mutant, indicating a role for the proteasome in dissociating elongation complexes. The genomic occupancies of Spt23 and Mga2 overlapped significantly with the genes bound by the proteasome. Finally, the proteasome acts in two distinct ways, one dependent and one independent of Spt23/Mga2 cleavage, providing evidence for cooperative gene regulation by the proteasome and its substrates. Keywords: ChIP-chip; genetic modification transcriptional profiling
2006-02-28 | GSE4272 | GEO