Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Microrchidia ATPases and 6mA DNA demethylase ALKBH1 act antagonistically on PRC2 to control gene expression for stress tolerance

ABSTRACT: The Microrchidia (MORC) ATPases are required for heterochromatin condensation and transposable element silencing in plants and animals. In plants, MORC proteins have been shown to be required for the efficient RNA-directed DNA methylation (RdDM) at specific chromatin regions and have a function in plant response to biotic stress. Here we provide first evidence linking MORC proteins with Polycomb-Repressive Complex 2 (PRC2). We show that rice MORC proteins interact with PRC2 proteins and are required for efficient PRC2-binding to genomic targets for H3K27me3 and gene repression. This function of MORC proteins is counteracted by ALKBH1, a DNA 6mA demethylase previously shown to impair PRC2 binding to a subset of the target. We find that OsMORC6b binding is enriched at gene transcriptional start sites, which overlaps largely with that of the PRC2 protein EMF2b and co-localizes with fine scale chromatin boundaries delimitating genic H3K27me3 domains from open chromatin. We further show that rice MORC proteins are required to maintain RdDM at CHH sequences at the upstream promoter region and H3K27me3 at the downstream body region for gene repression. These findings uncover novel function for MORC in chromatin regulation and have implications for MORC protein function in other eukaryotic organisms.

ORGANISM(S): Oryza sativa Japonica Group

PROVIDER: GSE267968 | GEO | 2025/05/12

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Arabidopsis MORC proteins function in the efficient establishment of RNA directed DNA methylation

Project description:The Microrchidia (MORC) family of ATPases are required for transposable element (TE) silencing and heterochromatin condensation in plants and animals, and C. elegans MORC-1 has been shown to topologically entrap and condense DNA. In Arabidopsis thaliana, mutation of MORCs has been shown to reactivate silent methylated genes and transposons and to decondense heterochromatic chromocenters, despite only minor changes in the maintenance of DNA methylation. Here we provide the first evidence localizing Arabidopsis MORC proteins to specific regions of chromatin and find that MORC4 and MORC7 are closely co-localized with sites of RNA directed DNA methylation (RdDM). We further show that MORC7, when tethered to DNA by an artificial zinc finger, can facilitate the establishment of RdDM. Finally, we show that MORCs are required for the efficient RdDM mediated establishment of DNA methylation and silencing of a newly integrated FWA transgene, even though morc mutations have no effect on the maintenance of preexisting methylation at the endogenous FWA gene. We propose that MORCs function as a molecular tether in RdDM complexes to reinforce RdDM activity for methylation establishment. These findings have implications for MORC protein function in a variety of other eukaryotic organisms.

2021-07-02 | PXD026674 | Pride

Arabidopsis MORC proteins function in the efficient establishment of RNA directed DNA methylation

2021-07-02 | GSE160285 | GEO

MORC proteins regulate transcription factor binding through mediating chromatin compaction at active chromatin regions

Project description:The Microrchidia (MORC) family proteins are evolutionarily conserved GHKL type ATPases involved in chromatin compaction and gene silencing. Arabidopsis MORC proteins act in the RNA-directed DNA methylation (RdDM) pathway where they act as molecular tethers to ensure the efficient establishment of RdDM and de novo gene silencing. However, they also have RdDM independent functions in which the underlying mechanism is unknown. In this study, we examined MORC binding regions that are devoid of RdDM to shed light on MORCs RdDM independent functions. We found that MORC proteins can compact chromatin, exclude the accessibility of DNA to transcription factors (TFs) and thereby repress gene expression. We also found that MORC-mediated repression is particularly important under stress conditions. In addition, we showed that MORC proteins may regulate TFs through direct or indirect interactions. These TFs in turn regulate their own transcription, indicating a feedforward loop. Our findings provide insights into the molecular mechanisms of MORC-mediated chromatin compaction and transcription regulation.

2023-03-27 | GSE212801 | GEO

The Polycomb Group Gene EMF2B is required for meristem determinacy and organ specification in rice flowers.

Project description:The Polycomb Repressive Complex 2 (PRC2) represses the transcriptional activity of target genes through trimethylation of Lysine 27 of Histone H3. The functions of the plant PRC2 have been chiefly described in Arabidopsis but specific PRC2 functions in other plant species, especially the cereals, are still largely unknown. Here we characterize mutants in the rice EMF2B gene, an ortholog of the Arabidopsis PRC2 gene EMBRYONIC FLOWER2 (EMF2). Loss of EMF2B in rice results in complete sterility, and mutant flowers have severe floral organ defects and indeterminacy that resemble loss of function mutants in rice E-function floral organ specification genes. Transcriptome analysis identified the E-function genes OsMADS1, OsMADS6 and OsMADS34 that are involved in floral development as differentially expressed in the emf2b mutant compared to wild type. OsMADS1 and OsMADS6 are known to be required for meristem determinacy in rice, and are down-regulated in the emf2b mutant, whereas OsMADS34 which interacts genetically with OsMADS1 was up-regulated. Chromatin immunoprecipitation for H3K27me3 followed by deep sequencing showed that all three genes are amongst the presumptive targets of PRC2 in the meristem. We propose that the PRC2 operates through a mechanism that involves regulation of E-function genes to play a major role in floral organ specification and floral meristem determinacy in rice, and possibly in other cereals. RNA-seq: The transcriptome of WT and emf2b rice panicles were compared via RNA-seq.

2014-10-31 | E-GEOD-49633 | biostudies-arrayexpress

Specific cPRC1 complexes are co-opted to mediate oncogenic gene repression in diffuse midline glioma

Project description:Diffuse midline glioma (DMG) is a fatal childhood brain tumour characterised primarily by mutant histone H3 (H3K27M). H3K27M causes a global reduction in Polycomb Repressive Complex 2 (PRC2)-mediated H3K27me3 by inhibiting PRC2 enzymatic activity. Paradoxically, PRC2 is essential in DMG tumour cells where residual complex activity is required for oncogenic gene repression, although the molecular mechanisms acting downstream of PRC2 in this context are poorly understood. Here, we’ve discovered this oncogenic gene repression is mediated by specific canonical PRC1 (cPRC1) formations. By combining CRISPR screening, biochemical and chromatin mapping approaches with functional perturbations we show that cPRC1 complexes containing CBX4 and PCGF4 drive oncogenic gene repression downstream of H3K27me3 in DMG cells. Remarkably, the altered H3K27me3 modification landscape characteristic of these tumours rewires the distribution of cPRC1 complexes on chromatin. CBX4 and PCGF4 containing cPRC1 accumulate at sites of H3K27me3 while other cPRC1 formations are displaced. Despite accounting for <5% of cPRC1 complexes in DMG, CBX4/PCGF4-containing complexes predominate as gene repressors. Our findings link the altered distribution of H3K27me3 with imbalanced cPRC1 function, promoting oncogenic gene repression in DMG cells, revealing new disease mechanisms and highlighting potential therapeutic opportunities in this incurable childhood brain tumour.

2025-06-24 | PXD058532 | Pride

Specific cPRC1 complexes are co-opted to mediate oncogenic gene repression in diffuse midline glioma

Project description:Summary Diffuse midline glioma (DMG) is a fatal childhood brain tumour characterised primarily by mutant histone H3 (H3K27M). H3K27M causes a global reduction in Polycomb Repressive Complex 2 (PRC2)-mediated H3K27me3 by inhibiting PRC2 enzymatic activity. Paradoxically, PRC2 is essential in DMG tumour cells where residual complex activity is required for oncogenic gene repression, although the molecular mechanisms acting downstream of PRC2 in this context are poorly understood. Here, we’ve discovered this oncogenic gene repression is mediated by specific canonical PRC1 (cPRC1) formations. By combining CRISPR screening, biochemical and chromatin mapping approaches with functional perturbations we show that cPRC1 complexes containing CBX4 and PCGF4 drive oncogenic gene repression downstream of H3K27me3 in DMG cells. Remarkably, the altered H3K27me3 modification landscape characteristic of these tumours rewires the distribution of cPRC1 complexes on chromatin. CBX4 and PCGF4 containing cPRC1 accumulate at sites of H3K27me3 while other cPRC1 formations are displaced. Despite accounting for <5% of cPRC1 complexes in DMG, CBX4/PCGF4-containing complexes predominate as gene repressors. Our findings link the altered distribution of H3K27me3 with imbalanced cPRC1 function, promoting oncogenic gene repression in DMG cells, revealing new disease mechanisms and highlighting potential therapeutic opportunities in this incurable childhood brain tumour.

2025-06-24 | PXD047451 | Pride

The Polycomb Group Gene EMF2B is required for meristem determinacy and organ specification in rice flowers.

2014-10-31 | GSE49633 | GEO

Cooperation between H3K27me3 and non-CG methylation in epigenetic regulation of genes in rice.

Project description:H3K27me3 is a repressive chromatin mark of genes and is catalyzed by homologs of Enhancer of zeste [E(z)], a component of Polycomb-repressive complex 2 (PRC2), while DNA methylation that occurs in CG and non-CG (CHG and CHH, where H is A, C or T) contexts is a hallmark of transposon silencing in plants. However, relationship between H3K27me3 and DNA methylation in gene repression remains unclear. In addition, the mechanism of PRC2 recruitment to specific genes is not known in plants. Here, we show that SDG711, a rice E(z) homolog, is required to maintain H3K27me3 of many developmental genes after shoot meristem to leaf transition and that many H3K27me3-marked developmental genes are also methylated at non-CG sites in the body regions. SDG711-binding and SDG711-mediated ectopic H3K27me3 also target genes methylated at non-CG sites. Conversely, mutation of OsDRM2, a major rice CHH methyltransferase, resulted in loss of SDG711-binding and H3K27me3 from many genes and their de-repression. Furthermore, we show that SDG711 physically interacts with OsDRM2 and a putative CHG methylation-binding protein. These results together suggest that the repression of many developmental genes may involve both DRM2-mediated non-CG methylation and PRC2-mediated H3K27me3 and that the two marks are not generally mutually exclusive but may cooperate in repression of developmentally regulated genes in rice.

2016-12-18 | GSE71640 | GEO

Phf19 links methylated lysine 36 of histone H3 to regulation of Polycomb activity [ChIP-Seq]

Project description:Polycomb group proteins are transcriptional repressors that play essential roles in regulating genes required for differentiation and embryonic development. The Polycomb repressive complex 2 (PRC2) contains the methyltransferase activity for lysine 27 on histone 3 (H3K27me3), which is a docking site for the PRC1 complex and leads to gene repression. However, the role of other histone modifications in regulating PRC2 activity is just beginning to be understood. Here we show that direct recognition of histone H3 methylated at lysine 36 (H3K36me), an mark associated with activation, by the PRC2 subunit Phf19 is required for the full enzymatic activity of the PRC2 complex. We provide structural evidence for this interaction by nuclear magnetic resonance spectroscopy (NMR). Using genome-wide chromatin binding analyses and expression analyses, we show that Phf19 binds to a subset of PRC2 targets in embryonic stem (ES) cells, and that this is required for their repression and for H3K27me3 deposition. These findings reveal that the H3K36me2/3-Phf19 interaction is essential for PRC2 complex activity and for proper regulation of gene repression in ES cells. We determined the genome binding/occupancy profile of Phf19, H3K36me3, H3K36me2, H3K27me3 and Suz12 by high throughput sequencing in mouse embryonic stem cells. For Phf19 two independent biological replicas were performed and Phf19 binding sites were defined as those sites (ChIP-seq peaks) present in both replicas. H3K27me3 was evaluated in control ES cells and cells depleted of Phf19 (shRd and shPhf19 respectively).

2012-10-16 | E-GEOD-41589 | biostudies-arrayexpress

Deletion of RING1A/B and loss of H2AK119ub1 affects PRC2 occupancy and H3K27me3 genome-wide

Project description:The chromatin modifying activities inherent to polycomb repressive complexes PRC1 and PRC2 play an essential role in gene regulation, cellular differentiation, and development. However, the mechanisms by which these complexes recognize their target sites and function together to form repressive chromatin domains remain poorly understood. Recruitment of PRC1 to target sites has been proposed to occur through a hierarchical process, dependent on the prior nucleation of PRC2 and placement of H3K27me3. Here, using a de novo targeting assay in mouse embryonic stem cells we unexpectedly discover that PRC1-dependent H2AK119ub1 leads to the recruitment of PRC2 and H3K27me3 to effectively initiate a polycomb domain. Genetic ablation of catalytic subunit of the PRC1 complex (RINGA/B) and ChIP-seq analysis of PRC1 and PRC2 components confirmed genome-wide decreases in PRC2 occupancy and H3K27me3 levels at PRC target sites. This activity is restricted to variant PRC1 complexes and genetic ablation experiments reveal that targeting of the variant PCGF1/PRC1 complex by KDM2B to CpG islands is required for polycomb domain formation and normal development. Together these observations provide a surprising new PRC1-dependent logic for PRC2 occupancy and polycomb domain formation. RING1A-/-;RING1Bfl/fl ES cells were treated with 800M-BM-5M tamoxifen for 48hours and compared to untreated control cells by ChIP-seq for RING1B, SUZ12, EZH2 and H3K27me3.

2014-05-27 | E-GEOD-55697 | biostudies-arrayexpress

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data