An epigenetic mark of polycomb response elements implemented by Trx/MLL/COMPASS
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ABSTRACT:
PROVIDER: PRJNA322547 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR3575250.fastq.gz | Fastqsanger.gz | |||
| SRR3575270.fastq.gz | Fastqsanger.gz | |||
| SRR3575280.fastq.gz | Fastqsanger.gz | |||
| SRR3575290.fastq.gz | Fastqsanger.gz | |||
| SRR3575300.fastq.gz | Fastqsanger.gz |
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Project description:In Drosophila, Polycomb Response Elements (PREs) are identified as genomic sequences allowing the maintenance of transcriptional repression in the absence of the initiating signal. Although PREs in Drosophila are well characterized, the existence of mammalian PRE-like elements remains debated. Accumulating evidence supports a model in which CpG islands function to recruit Polycomb-Group complexes (PcG), however, it is not evident which subclasses of CpG islands serve as PREs. Trithorax (Trx), which is required for positive regulation of gene expression in Drosophila, is known to co-bind Drosophila PREs where it is thought to antagonize polycomb-dependent silencing of nearby genes. Here, we demonstrate the existence of Trx-dependent H3K4 dimethylation loci that specifically mark Drosophila PREs and are required for the maintenance of expression of the nearby genes. Similarly, in human cells, we find ~ 3000 MLL1 (human Trx homologue)-dependent H3K4 dimethylation loci, which correlate strongly with CpG island density. In the absence of MLL1 and H3K4 dimethylation at these loci, there is an increase in H3K27 trimethylation levels, suggesting these sites can recruit Polycomb Repressive Complex 2 (PRC2). By inhibiting PRC2-dependent silencing in the absence of MLL1, we establish that a balance exists between MLL1 and PRC2, and their respective capacity to maintain or repress transcription. Thus, by investigating a conserved function between Trx and MLL1, we provide rules for the identification of CpG island subclasses serving as PRE-like sequences within the human genome. To examine changes in histone-modification profiles and gene expression after depletion of Trx in Drosophila S2 cells, and MLL1 in human HCT116 cells. We also treated MLL1-NULL HCT116 cells with GSK126 (5uM) for 4 days and measured changes in gene expression.
2016-07-26 | E-GEOD-81795 | biostudies-arrayexpress
Project description:In Drosophila, Polycomb Response Elements (PREs) are identified as genomic sequences allowing the maintenance of transcriptional repression in the absence of the initiating signal. Although PREs in Drosophila are well characterized, the existence of mammalian PRE-like elements remains debated. Accumulating evidence supports a model in which CpG islands function to recruit Polycomb-Group complexes (PcG), however, it is not evident which subclasses of CpG islands serve as PREs. Trithorax (Trx), which is required for positive regulation of gene expression in Drosophila, is known to co-bind Drosophila PREs where it is thought to antagonize polycomb-dependent silencing of nearby genes. Here, we demonstrate the existence of Trx-dependent H3K4 dimethylation loci that specifically mark Drosophila PREs and are required for the maintenance of expression of the nearby genes. Similarly, in human cells, we find ~ 3000 MLL1 (human Trx homologue)-dependent H3K4 dimethylation loci, which correlate strongly with CpG island density. In the absence of MLL1 and H3K4 dimethylation at these loci, there is an increase in H3K27 trimethylation levels, suggesting these sites can recruit Polycomb Repressive Complex 2 (PRC2). By inhibiting PRC2-dependent silencing in the absence of MLL1, we establish that a balance exists between MLL1 and PRC2, and their respective capacity to maintain or repress transcription. Thus, by investigating a conserved function between Trx and MLL1, we provide rules for the identification of CpG island subclasses serving as PRE-like sequences within the human genome.
2016-07-26 | GSE81795 | GEO
Project description:Polycomb response elements (PREs) are specific DNA sequences that stably maintain the developmental pattern of gene expression. Drosophila PREs are well characterized, whereas the existence of PREs in mammals remains debated. Accumulating evidence supports a model in which CpG islands recruit Polycomb group (PcG) complexes; however, which subset of CGIs is selected to serve as PREs is unclear. Trithorax (Trx) positively regulates gene expression in Drosophila and co-occupies PREs to antagonize Polycomb-dependent silencing. Here we demonstrate that Trx-dependent H3K4 dimethylation (H3K4me2) marks Drosophila PREs and maintains the developmental expression pattern of nearby genes. Similarly, the mammalian Trx homolog, MLL1, deposits H3K4me2 at CpG-dense regions that could serve as PREs. In the absence of MLL1 and H3K4me2, H3K27me3 levels, a mark of Polycomb repressive complex 2 (PRC2), increase at these loci. By inhibiting PRC2-dependent H3K27me3 in the absence of MLL1, we can rescue expression of these loci, demonstrating a functional balance between MLL1 and PRC2 activities at these sites. Thus, our study provides rules for identifying cell-type-specific functional mammalian PREs within the human genome.
| S-EPMC4996622 | biostudies-literature
Project description:This study investigated the role Complex of Proteins Associated with Set1 (COMPASS) in heart development. These are evolutionarily highly conserved multiprotein complexes required for H3K4 methylation. In Drosophila, their core subunits are Set1, Trx, and Trr. We studied flies deficient for either of these three subunits their hearts. These flies showed high lethality at eclosion (emergence of adult flies from their pupal case) and significantly shortened lifespans for the adults that did emerge. Furthermore, their hearts showed reduced H3K4 monomethylation (H3K4me1) and dimethylation (H3K4me2), and significantly altered gene expression patterns. The data revealed that each of the COMPASS core subunits (Set1, Trx, and Trr) control methylation of different sets of genes with distinct temporal activity: Set1 throughout, whereas Trr was active early and Trx at later stages of heart development. We found that many metabolic pathways were active early in development and throughout, while muscle and heart differentiation processes were methylated during later stages of development. Taken together, the findings demonstrate the importance of COMPASS complexes during heart development, therewith supporting their implication in congenital heart diseases.
2024-01-03 | GSE240313 | GEO
Project description:The correlation between DNA methylation and a subset of histone post-translational modifications (positive and negative) has hinted at an underlying regulatory crosstalk between histone marks and DNA methylation in patterning the human DNA methylome, an idea further supported by corresponding alterations to both histone marks and DNA methylation during malignant transformation. This study investigated the framework by which histone marks influence DNA methylation at a genome-wide level. Using RNAi in a pluripotent human embryonic carcinoma cell line we depleted essential components of the MLL/COMPASS, polycomb repressive complex 2 (PRC2), and PRC1 histone modifying complexes that establish, respectively, the post-translational modifications H3K4me3, H3K27me3, and H2AK119ub, and assayed the impact of the subsequent depletion of these marks on the DNA methylome. Absence of H2AK119ub resulted predominantly in hypomethylation across the genome. Depletion of H3K4me3 and, surprisingly, H3K27me3 caused CpG island hypermethylation at a subset of loci. Intriguingly, many promoters were co-regulated by all three histone marks, becoming hypermethylated with loss of H3K4me3 or H3K27me3 and hypomethylated with depletion of H2AK119ub, and many of these co-regulated loci were among those commonly targeted for aberrant hypermethylation in cancer. Taken together, our results elucidate novel roles for polycomb and MLL/COMPASS in regulating DNA methylation and define targets of this regulation.
| S-EPMC4171634 | biostudies-literature
Project description:Histone H3 lysine 4 trimethylation (H3K4me3) facilitates recruitment of transcription factors and epigenetic effectors to promote transcriptional activation and ensure cellular identity. This conserved histone mark is implemented by the COMPASS (COMplex of Proteins ASsociated with Set1) family of H3K4 methyltransferases. COMPASS members Set1A and Set1B have been accredited as primary depositors of global H3K4me3 in mammalian cells. Our previous studies in mouse embryonic stem cells (ESCs) demonstrated that deleting the enzymatic SET domain of Set1A does not perturb bulk H3K4me3, indicating possible compensatory roles played by other COMPASS methyltransferases. Here, we generated a series of ESC lines harboring compounding mutations of the COMPASS enzymes. We find that Set1B is functionally redundant to Set1A in implementing H3K4me3 at highly expressed genes, while Mll2 deposits H3K4me3 at less transcriptionally active promoters. Furthermore, Set1A and Set1B are responsible for broad H3K4me3 peaks, whereas Mll2 establishes H3K4me3 with narrow breadth. Most importantly, Mll2 helps preserve global H3K4me3 levels and peak breadth. Our results illustrate the biological flexibility of such enzymes in regulating transcription in a context-dependent manner to maintain stem cell identity, which could assist our understanding of their disease liability.
2020-06-27 | GSE152595 | GEO
Project description:Distinct roles for COMPASS core subunits Set1, Trx, and Trr in the epigenetic regulation of Drosophila heart development
| PRJNA1003127 | ENA
Project description:The Caenorhabditis elegans oxidative stress response transcription factor, SKN-1, is essential for the maintenance of redox homeostasis and is a functional ortholog of the Nrf family of transcription factors. The numerous levels of regulation that govern these transcription factors underscore their importance. Here, we add a thioredoxin, encoded by trx-1, to the expansive list of SKN-1 regulators. We report that loss of trx-1 promotes nuclear localization of intestinal SKN-1 in a redox-independent, cell non-autonomous fashion from the ASJ neurons. Furthermore, this regulation is not general to the thioredoxin family, as two other C. elegans thioredoxins TRX-2 and TRX-3 do not play a role in this process. Moreover, TRX-1-dependent regulation requires signaling from the p38 MAPK signaling pathway. However, while TRX-1 regulates SKN-1 nuclear localization, SKN-1 transcriptional activity remains largely unaffected. Interestingly, RNA-Seq revealed that loss of trx-1 elicits a general, organism-wide down-regulation of several classes of genes; those encoding for collagens and lipid transport and localization being most prevalent. However, one prominent lipase-related gene, lips-6, is highly up regulated upon loss of trx-1 in a skn-1-dependent manner. Together, these results uncover a novel role for a thioredoxin in regulating intestinal SKN-1 nuclear localization in a cell non-autonomous manner, thereby contributing to the understanding of the processes involved in maintaining redox homeostasis throughout an organism. Four samples were analyzed: Two nematode strains were analyzed, each under non-stressed and stressed (10mM NaAs) conditions
2016-04-01 | E-GEOD-77976 | biostudies-arrayexpress
Project description:The Caenorhabditis elegans oxidative stress response transcription factor, SKN-1, is essential for the maintenance of redox homeostasis and is a functional ortholog of the Nrf family of transcription factors. The numerous levels of regulation that govern these transcription factors underscore their importance. Here, we add a thioredoxin, encoded by trx-1, to the expansive list of SKN-1 regulators. We report that loss of trx-1 promotes nuclear localization of intestinal SKN-1 in a redox-independent, cell non-autonomous fashion from the ASJ neurons. Furthermore, this regulation is not general to the thioredoxin family, as two other C. elegans thioredoxins TRX-2 and TRX-3 do not play a role in this process. Moreover, TRX-1-dependent regulation requires signaling from the p38 MAPK signaling pathway. However, while TRX-1 regulates SKN-1 nuclear localization, SKN-1 transcriptional activity remains largely unaffected. Interestingly, RNA-Seq revealed that loss of trx-1 elicits a general, organism-wide down-regulation of several classes of genes; those encoding for collagens and lipid transport and localization being most prevalent. However, one prominent lipase-related gene, lips-6, is highly up regulated upon loss of trx-1 in a skn-1-dependent manner. Together, these results uncover a novel role for a thioredoxin in regulating intestinal SKN-1 nuclear localization in a cell non-autonomous manner, thereby contributing to the understanding of the processes involved in maintaining redox homeostasis throughout an organism.
2016-04-01 | GSE77976 | GEO
Project description:MLL3/KMT2C is a COMPASS family member and tumor suppressor that functions as a histone H3K4 mono-methyltransferase at enhancers. Human cancer genome sequencing studies have identified frequent MLL3 point mutations, however, the question of how these mutations alter MLL3 function and contribute to oncogenesis remains unanswered. Here, we have characterized a cancer mutational hot spot in the MLL3 Plant Homeo Domain (PHD) repeats that correlates with poor patient survival. Cancer-associated mutations in the MLL3-PHD disrupt interaction with the BAP1 deubiquitinase complex. BAP1 loss-of-function in cancer cells significantly reduces MLL3 recruitment to enhancers regions, resulting in reduced H3K4me1 and increased H3K27me3 levels at these loci. Notably, we find that increased H3K27me3 levels in BAP1 null cells are due to decreased MLL3/UTX/COMPASS occupancy. Reducing H3K27me3 through PRC2 catalytic inhibition resets the pattern of gene expression in cells with defective MLL3- BAP1-UTX activity and impairs tumor proliferation in cancer cells with MLL3 mutations. This study provides a molecular mechanism to explain the role of MLL3 PHD mutations in cancer pathogenesis. Therefore, based on these observations, we propose a potential therapeutic strategy for cancers harboring MLL3/COMPASS mutations by resetting the Polycomb/COMPASS epigenetic balanced state of gene expression.
2018-05-27 | GSE97326 | GEO