Novel genetically engineered H3.3G34R model reveals cooperation with ATRX loss in upregulation of PRC2 targets, NOTCH activation, promotion of neuronal lineage
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ABSTRACT:
PROVIDER: PRJNA813299 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR18247976.fastq.gz | Fastqsanger.gz | |||
| SRR18247977.fastq.gz | Fastqsanger.gz | |||
| SRR18247978.fastq.gz | Fastqsanger.gz | |||
| SRR18247979.fastq.gz | Fastqsanger.gz | |||
| SRR18247980.fastq.gz | Fastqsanger.gz |
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Project description:Pediatric high-grade gliomas (pHGGs) are an aggressive pediatric CNS tumor, often characterized by mutations in H3F3A, the gene that encodes Histone H3.3 (H3.3). Substitution of the Glycine at position 34 of H3.3 with either Arginine or Valine (H3.3G34R/V), was recently described and characterized in a large cohort of pHGG samples as occurring in 5-20% of pHGGs. We developed a genetically engineered mouse model (GEMM) that incorporates PDGF-A activation, TP53 loss and the H3.3G34R mutation both in the presence and loss of Alpha thalassemia/mental retardation syndrome X-linked (ATRX), which is commonly mutated in H3.3G34 mutant pHGGs. Nestin Tv-a; p53 fl/fl and Nestin Tv-a; p53 fl/fl; ATRX fl/fl mice were injected with DF-1 cells transfected with RCAS-Cre, RCAS-PDGFA, and either RCAS-H3.3WT-GFP or RCAS-H3.3G34R-GFP. By 210 days old, a majority of mice develop symptoms of tumor growth (erratic behavior, domed head, ataxia) or have 20% weight loss and are euthanized. Our goal is to develop a biologically relevant animal model of pHGG in order to probe the downstream effects of the H3.3G34R mutation in the context of vital co-occurring mutations.
2023-03-04 | GSE197988 | GEO
Project description:BackgroundPediatric high-grade gliomas (pHGGs) are aggressive pediatric CNS tumors and an important subset are characterized by mutations in H3F3A, the gene that encodes Histone H3.3 (H3.3). Substitution of Glycine at position 34 of H3.3 with either Arginine or Valine (H3.3G34R/V), was recently described and characterized in a large cohort of pHGG samples as occurring in 5-20% of pHGGs. Attempts to study the mechanism of H3.3G34R have proven difficult due to the lack of knowledge regarding the cell-of-origin and the requirement for co-occurring mutations for model development. We sought to develop a biologically relevant animal model of pHGG to probe the downstream effects of the H3.3G34R mutation in the context of vital co-occurring mutations.MethodsWe developed a genetically engineered mouse model (GEMM) that incorporates PDGF-A activation, TP53 loss and the H3.3G34R mutation both in the presence and loss of Alpha thalassemia/mental retardation syndrome X-linked (ATRX), which is commonly mutated in H3.3G34 mutant pHGGs.ResultsWe demonstrated that ATRX loss significantly increases tumor latency in the absence of H3.3G34R and inhibits ependymal differentiation in the presence of H3.3G34R. Transcriptomic analysis revealed that ATRX loss in the context of H3.3G34R upregulates Hoxa cluster genes. We also found that the H3.3G34R overexpression leads to enrichment of neuronal markers but only in the context of ATRX loss.ConclusionsThis study proposes a mechanism in which ATRX loss is the major contributor to many key transcriptomic changes in H3.3G34R pHGGs.Accession numberGSE197988.
| S-EPMC9950856 | biostudies-literature
Project description:We disrupted the RNA binding region in endogenous ATRX and tested localization of ATRX, EZH2 and H3K27me3 by CUT&RUN. We show that ATRX-RNA binding is important to regulate ATRX and PRC2 localization to specific genes.
2020-02-24 | GSE130452 | GEO
Project description:Heterochromatin Protein 1 (HP1) is a major regulator of chromatin structure and function. In animals, the network of proteins interacting with HP1 is mainly associated with constitutive heterochromatin marked by H3K9me3. HP1 physically interacts with the putative orthologue of the SNF2 chromatin remodeler ATRX, which controls deposition of the histone variant H3.3 in mammals. In Arabidopsis thaliana, we show that the orthologue of ATRX participates in H3.3 deposition and characterize the function of conserved domains of plant ATRX. We show that the plant Like HP1 (LHP1) interacts with ATRX through domains that evolved specifically in land plants ancestors. Interaction between ATRX and LHP1 affects the expression of a limited subset of genes controlled by the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), including the flowering time regulator FLC. In the context of flowering time, ATRX function requires the novel LHP1-interacting domain and the ATPase of the ATRX SNF2 helicase. We conclude that distinct evolutionary pathways led to interaction between ATRX and HP1 in mammals or its counterpart LHP1 in plants, resulting in distinct modes of transcriptional regulation.
2018-06-26 | GSE101777 | GEO
Project description:Heterochromatin in the eukaryotic genome is rigorously controlled by the concerted action of protein factors and RNAs. Here, we investigate the RNA binding function of ATRX, a chromatin remodeler with roles in silencing of repetitive regions of the genome and in recruitment of the polycomb repressive complex 2 (PRC2). We identify ATRX RNA binding regions (RBRs) and discover that the major ATRX RBR lies within the N-terminal region of the protein, distinct from its PHD and helicase domains. Deletion of this ATRX RBR (ATRXRBR) compromises ATRX interactions with RNAs in vitro and in vivo and alters its chromatin binding properties. Genome-wide studies reveal that loss of RNA interactions results in a redistribution of ATRX on chromatin. Finally, our studies identify a role for ATRX-RNA interactions in regulating PRC2 localization to a subset of polycomb target genes.
2020-03-09 | PXD017806 | Pride
Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
2017-12-31 | GSE100462 | GEO
Project description:Examining the role of ATRX-RNA interactions in ATRX and PRC2 localization and gene expression.
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Project description:ATRX is a chromatin remodelling protein of the SWI/SNF family, mutations in which cause alpha thalassemia X-linked (ATRX) intellectual disability syndrome and are highly associated with a number of cancers characterized by alternative lengthening of telomeres. ATRX functions with the histone chaperone DAXX to facilitate deposition of the histone variant H3.3 at heterochromatic regions such as telomere and pericentric repeats, resulting in a unique form of heterochromatin characterized by both trimethylation of histone H3 at lysine 9 (H3K9me3) and H3.3. How ATRX is recruited to these regions remain unclear.To better understand it, we therefore used immunoprecipitation-coupled to mass spectrometry (IP-MS) to identify potential factors that interact with ATRX and may promote its localization and function. Based on our proteomics results, we identified known ATRX-interacting proteins, DAXX and MRE11. We also identified a number of proteins that have been genetically linked to G-quadruplex structures. Interestingly, we identified members of DNA replcation machinery MCM complex (e.g. MCM2, MCM4, MCM6, and MCM7) and the faciliates chromatin transcription (FACT) comeplex as novel ATRX-interacting proteins. We then verified the interaction of ATRX to MCM proteins and FACT subunits by co-immunoprecipition/immunoblot and proximity ligation assay.
2020-06-03 | MSV000085543 | MassIVE
Project description:Heterochromatin in the eukaryotic genome is rigorously controlled by the concerted action of protein factors and RNAs. Here, we investigate the RNA binding function of ATRX, a chromatin remodeler with roles in silencing of repetitive regions of the genome and in recruitment of the polycomb repressive complex 2 (PRC2). We identify ATRX RNA binding regions (RBRs) and discover that the major ATRX RBR lies within the N-terminal region of the protein, distinct from its PHD and helicase domains. Deletion of this ATRX RBR (ATRXΔRBR) compromises ATRX interactions with RNAs in vitro and in vivo and alters its chromatin binding properties. Genome-wide studies reveal that loss of RNA interactions results in a redistribution of ATRX on chromatin. Finally, our studies identify a role for ATRX-RNA interactions in regulating PRC2 localization to a subset of polycomb target genes.
| S-EPMC7203109 | biostudies-literature
Project description:Herpes simplex virus 1 (HSV-1) transcribes its genome in a highly coordinated temporal cascade, utilizing the host RNA polymerase II (Pol II). Repression of transcription precedes the cascade's progression in a process requiring viral immediate early (IE) genes, in a phenomenon termed Transient Immediate Early gene Mediated Repression (TIEMR). Given that components of promyelocytic leukaemia nuclear bodies (PML-NBs) are known to rapidly engage incoming HSV-1 genomes, we investigated their potential role in TIEMR regulation. Using siRNA knockdown of PML-NB constituents (PML, DAXX, and ATRX), we unexpectedly observed that ATRX depletion resulted in a significant reduction in nascent viral transcription on viral IE promoters at 1.5 hours post-infection (hpi). ChIP-Seq analysis indicated ATRX is associated with both highly transcriptionally active and transcriptionally restricted regions, indicating that ATRX has diverse functions in the viral genome. We show here that ATRX association with active transcription on IE genes is correlated to the presence of G-quadruplexes (G4s). Drug stabilization of G4s mimicked the effects of ATRX knockdown, significantly reducing transcription initiation on IE genes. These findings suggest that ATRX promotes transcriptional initiation of HSV-1 IE genes by preventing G4 formation. In sum, our results reveal a previously unrecognized pro-transcriptional role for ATRX early in HSV-1 infection.
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