Loss of a heterochromatin anchor rescues altered genome organization and EDMD muscle defects triggered by a laminopathy mutation
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ABSTRACT:
ORGANISM(S): Caenorhabditis elegans
PROVIDER: GSE136577 | GEO | 2020/12/31
REPOSITORIES: GEO
Similar Datasets
Project description:Point mutations in nuclear structural protein laminA produce rare and generally tissue-specific diseases called laminopathies. The introduction of a human Emery Dreifuss Muscular Dystrophy (EDMD)-inducing mutation (laminA-Y45C) into C. elegans lamin (LMN-Y59C), recapitulates many EDMD phenotypes, and results in hyper-sequestration of heterochromatic arrays at the nuclear periphery. Using muscle-specific Emerin Dam-ID we show that the LMN-Y59C mutation also leads to misorganization of endogenous chromatin. We find increased perinuclear anchoring primarily along chromosome arms, and enhanced release of chromosomal cores. Coincidentally, Y59C worms have reduced locomotion and compromised sarcomere integrity. By coupling this mutation with deletion of the perinuclear chromodomain protein CEC-4, which tethers H3K9-methylated chromatin, we rescue the EDMD-like physiology and ultrastructural defects in sarcomeres. It further counteracts the altered spatial organization of chromosomal sequences, particularly along chromosomal arms. The data in this submission refer to the identification of chromatin enriched at the nuclear periphery (as measured by interaction with Dam::EMR-1) in muscle cells of L3/L4 control animals or cec-4 mutants expressing either GFP::LMN-1 (wild type lamin) or GFP::LMN-1(Y59C).
2020-12-31 | GSE135850 | GEO
Project description:Point mutations in nuclear structural protein lamin A produce rare, tissue-specific diseases called laminopathies. The introduction of a human Emery Dreifuss Muscular Dystrophy (EDMD)-inducing mutation (lamin A-Y45C) into C. elegans lamin (LMN-Y59C), recapitulates many EDMD phenotypes, and correlates with hyper-sequestration of heterochromatic arrays at the nuclear periphery. Using muscle-specific emerin Dam-ID, we also document the misorganization of endogenous chromatin in the LMN-Y59C mutant. We score increased perinuclear positioning along chromosome arms, and enhanced release within chromosomal cores. Coincidentally, Y59C worms have reduced locomotion and compromised sarcomere integrity. By coupling the Y59C mutation with deletion of the perinuclear chromodomain protein CEC-4, which tethers H3K9-methylated chromatin, we rescue the EDMD-like physiology and ultrastructural defects in sarcomeres. Deletion of cec-4 also rescued the Y59C-induced changes in chromatin organization. The promoters of genes that change position in the LMN-Y59C mutant, are enriched for E2F (EFL-1/-2) binding sites, consistent with previous studies implicating the Rb-E2F interaction with lamin A in muscle dysfunction. Gene expression changes provoked by LMN-Y59C are also largely reversed by cec-4 deletion. In summary, the ablation of a perinuclear H3K9me-anchor can counteract the dominant muscle-specific defects provoked by a laminopathic mutation, implicating peripheral chromatin organization in the control of muscle integrity.
2020-12-31 | GSE136576 | GEO
Project description:Loss of a heterochromatin anchor rescues altered genome organization and EDMD muscle defects triggered by a laminopathy mutation
| PRJNA562716 | ENA
Project description:DamID: Loss of a heterochromatin anchor rescues altered genome organization and EDMD muscle defects triggered by a laminopathy mutation
| PRJNA560279 | ENA
Project description:RNA-seq: Loss of a heterochromatin anchor rescues altered genome organization and EDMD muscle defects triggered by a laminopathy mutation
| PRJNA562715 | ENA
Project description:LMNA encodes the A-type lamins that are part of the nuclear scaffold. Mutations in LMNA can cause a variety of disorders called laminopathies, including Hutchinson-Gilford progeria syndrome (HGPS), atypical Werner syndrome, and Emery-Dreifuss muscular dystrophy. Previous work has shown that treatment of HGPS cells with the mTOR inhibitor rapamycin or with the rapamycin analog everolimus corrects several of the phenotypes seen at the cellular level-at least in part by increasing autophagy and reducing the amount of progerin, the toxic form of lamin A that is overproduced in HGPS patients. Since other laminopathies also result in production of abnormal and potentially toxic lamin proteins, we hypothesized that everolimus would also be beneficial in those disorders. To test this, we applied everolimus to fibroblast cell lines from six laminopathy patients, each with a different mutation in LMNA Everolimus treatment increased proliferative ability and delayed senescence in all cell lines. In several cell lines, we observed that with treatment, there is a significant improvement in nuclear blebbing, which is a cellular hallmark of HGPS and other lamin disorders. These preclinical results suggest that everolimus might have clinical benefit for multiple laminopathy syndromes.
| S-EPMC5910873 | biostudies-literature
Project description:Mutations in the nuclear structural protein lamin A produce rare, tissue-specific diseases called laminopathies. The introduction of a human Emery-Dreifuss muscular dystrophy (EDMD)-inducing mutation into the C. elegans lamin (LMN-Y59C), recapitulates many muscular dystrophy phenotypes, and correlates with hyper-sequestration of a heterochromatic array at the nuclear periphery in muscle cells. Using muscle-specific emerin Dam-ID in worms, we monitored the effects of the mutation on endogenous chromatin. An increased contact with the nuclear periphery along chromosome arms, and an enhanced release of chromosomal centers, coincided with the disease phenotypes of reduced locomotion and compromised sarcomere integrity. The coupling of the LMN-Y59C mutation with the ablation of CEC-4, a chromodomain protein that anchors H3K9-methylated chromatin at the nuclear envelope (NE), suppressed the muscle-associated disease phenotypes. Deletion of cec-4 also rescued LMN-Y59C-linked alterations in chromatin organization and some changes in transcription. Sequences that changed position in the LMN-Y59C mutant, are enriched for E2F (EFL-2)-binding sites, consistent with previous studies suggesting that altered Rb-E2F interaction with lamin A may contribute to muscle dysfunction. In summary, we were able to counteract the dominant muscle-specific defects provoked by LMNA mutation by the ablation of a lamin-associated H3K9me anchor, suggesting a novel therapeutic pathway for EDMD.
| S-EPMC7111258 | biostudies-literature
Project description:Mutations in LMNA, which encodes the nuclear proteins Lamin A/C, can cause cardiomyopathy and conduction disorders. Here, we employ induced pluripotent stem cells (iPSCs) generated from human cells carrying heterozygous K219T mutation on LMNA to develop a disease model. Cardiomyocytes differentiated from these iPSCs, and which thus carry K219T-LMNA, have altered action potential, reduced peak sodium current and diminished conduction velocity. Moreover, they have significantly downregulated Nav1.5 channel expression and increased binding of Lamin A/C to the promoter of SCN5A, the channel's gene. Coherently, binding of the Polycomb Repressive Complex 2 (PRC2) protein SUZ12 and deposition of the repressive histone mark H3K27me3 are increased at SCN5A. CRISPR/Cas9-mediated correction of the mutation re-establishes sodium current density and SCN5A expression. Thus, K219T-LMNA cooperates with PRC2 in downregulating SCN5A, leading to decreased sodium current density and slower conduction velocity. This mechanism may underlie the conduction abnormalities associated with LMNA-cardiomyopathy.
| S-EPMC6531493 | biostudies-literature
Project description:Heterochromatic regions represent a significant portion of the mammalian genome and have been implied in several important cellular processes, including cell division and genomic stability. However, its composition and dynamics remain largely unknown. To better understand how heterochromatin functions and how it is organized within the context of the cell nucleus, we have developed molecular tools allowing the targeting of virtually any nuclear factor specifically to heterochromatic regions and, thereby, the manipulation, also in a temporally controlled manner, of its composition. To validate our approach, we have ectopically targeted MeCP2 chromatin binding deficient Rett mutants to constitutive heterochromatic regions and analyze its functional consequences. We could show that, once bound to their endogenous target regions, their ability to re-organize higher order chromatin structure is restored. Furthermore, a temporally controlled targeting strategy allowed us to monitor MeCP2-mediated chromatin rearrangements in vivo and to visualize large-scale chromatin movements over several micrometers, as well as heterochromatic foci fusion events. This novel strategy enables specific tethering of any protein to heterochromatin and lays the ground for controlled manipulation of its composition and organization.
| S-EPMC3526307 | biostudies-literature
Project description:Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomal dominant disease of the hematopoietic system, which is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. Currently no suitable animal models exist for FPD/AML as Runx1+/- mice and zebrafish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells (iPSCs) from two patients in a family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in one FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients. Here, we derived iPSCs from two FPD/AML patients and demonstrated that these iPSCs have a megakaryopoietic defect in culture. Importantly we were able to rescue the megakaryopoietic defect by correcting the RUNX1 mutation with a gene targeting strategy enhanced by zinc finger nucleases (ZFNs). Three independent samples were obtained for each time point.
2014-07-01 | E-GEOD-54295 | biostudies-arrayexpress