Gain and loss of function variants in EZH1 disrupt neurogenesis and cause dominant and recessive neurodevelopmental disorders [RNA-seq]
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PROVIDER: PRJNA942914 | ENA |
REPOSITORIES: ENA
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Project description:Genetic disruption of chromatin regulators is frequently found in neurodevelopmental disorders (NDDs). While chromatin regulators are attractive therapeutic targets, studies to determine their implication in the etiology of NDDs are limited, preventing advances in diagnosis and treatment strategies. Here, we uncover pathogenic variants in the chromatin modifier Enhancer of Zeste Homologue 1 (EZH1) as the cause of overlapping dominant and recessive NDDs in 19 individuals. EZH1 encodes one of the two alternative histone H3 lysine 27 (H3K27) methyltransferases of the Polycomb Repressive Complex 2 (PRC2). Unlike the other PRC2 subunits, which are associated with the pathogenesis of human cancers and developmental disorders with overgrowth, the implication of EZH1 in human development and disease is largely unknown. Using cellular models and biochemical studies, we demonstrate that EZH1 variants identified in our study alter EZH1 molecularly. While recessive variants are EZH1 loss of function (LOF) variants that impair EZH1 expression, dominant variants are all missense mutations that affect evolutionarily conserved aminoacids likely impacting EZH1 structure or function. Accordingly, we found increased H3K27 methyltransferase activity for two EZH1 missense variants we tested, thus generating EZH1 gain of function (GOF) variants. Furthermore, we show that EZH1 is necessary and sufficient to differentiate neural stem cells in the developing chick embryo neural tube. Finally, using human pluripotent stem cell (hPSC)-derived neural cultures and forebrain organoids, we demonstrate that EZH1 LOF and GOF variation perturbs cortical projection neuron differentiation. Our work identifies EZH1 LOF and GOF variants as the genetic basis of previously undefined recessives and dominant NDDs and uncovers an essential role of EZH1 in regulating neurogenesis.
2023-05-04 | GSE210465 | GEO
Project description:Genetic disruption of chromatin regulators is frequently found in neurodevelopmental disorders (NDDs). While chromatin regulators are attractive therapeutic targets, studies to determine their implication in the etiology of NDDs are limited, preventing advances in diagnosis and treatment strategies. Here, we uncover pathogenic variants in the chromatin modifier Enhancer of Zeste Homologue 1 (EZH1) as the cause of overlapping dominant and recessive NDDs in 19 individuals. EZH1 encodes one of the two alternative histone H3 lysine 27 (H3K27) methyltransferases of the Polycomb Repressive Complex 2 (PRC2). Unlike the other PRC2 subunits, which are associated with the pathogenesis of human cancers and developmental disorders with overgrowth, the implication of EZH1 in human development and disease is largely unknown. Using cellular models and biochemical studies, we demonstrate that EZH1 variants identified in our study alter EZH1 molecularly. While recessive variants are EZH1 loss of function (LOF) variants that impair EZH1 expression, dominant variants are all missense mutations that affect evolutionarily conserved aminoacids likely impacting EZH1 structure or function. Accordingly, we found increased H3K27 methyltransferase activity for two EZH1 missense variants we tested, thus generating EZH1 gain of function (GOF) variants. Furthermore, we show that EZH1 is necessary and sufficient to differentiate neural stem cells in the developing chick embryo neural tube. Finally, using human pluripotent stem cell (hPSC)-derived neural cultures and forebrain organoids, we demonstrate that EZH1 LOF and GOF variation perturbs cortical projection neuron differentiation. Our work identifies EZH1 LOF and GOF variants as the genetic basis of previously undefined recessives and dominant NDDs and uncovers an essential role of EZH1 in regulating neurogenesis.
2023-05-04 | GSE227014 | GEO
Project description:Gain and loss of function variants in EZH1 disrupt neurogenesis and cause dominant and recessive neurodevelopmental disorders [ChIP-seq]
| PRJNA865756 | ENA
Project description:Gain and loss of function variants in EZH1 disrupt neurogenesis and cause overlapping neurodevelopmental disorders.
| PRJNA942909 | ENA
Project description:Vesicle biogenesis, trafficking and signaling via Endoplasmic reticulum-Golgi network support essential developmental processes and their disruption lead to neurodevelopmental disorders and neurodegeneration. We report that de novo missense variants in ARF3, encoding a small GTPase regulating Golgi dynamics, cause a developmental disease in humans impairing nervous system and skeletal formation. Microcephaly-associated ARF3 variants affect residues within the guanine nucleotide binding pocket and variably perturb protein stability and GTP/GDP binding. Functional analysis demonstrates variably disruptive consequences of ARF3 variants on Golgi morphology, vesicles assembly and trafficking. Disease modeling in zebrafish validates further the dominant behavior of the mutants and their differential impact on brain and body plan formation, recapitulating the variable disease expression. In-depth in vivo analyses traces back impaired neural precursors' proliferation and planar cell polarity-dependent cell movements as the earliest detectable effects. Our findings document a key role of ARF3 in Golgi function and demonstrate its pleiotropic impact on development.
| S-EPMC9652361 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-05-04 | GSE227016 | GEO
Project description:The Roundabout (Robo) receptors, located on growth cones of neurons, induce axon repulsion in response to the extracellular ligand Slit. The Robo family of proteins controls midline crossing of commissural neurons during development in flies. Mono- and bi-allelic variants in human ROBO1 (HGNC: 10249) have been associated with incomplete penetrance and variable expressivity for a breath of phenotypes, including neurodevelopmental defects such as strabismus, pituitary defects, intellectual impairment, as well as defects in heart and kidney. Here, we report two novel ROBO1 variants associated with very distinct phenotypes. A homozygous missense p.S1522L variant in three affected siblings with nystagmus; and a monoallelic de novo p.D422G variant in a proband who presented with early-onset epileptic encephalopathy. We modeled these variants in Drosophila and first generated a null allele by inserting a CRIMIC T2A-GAL4 in an intron. Flies that lack robo1 exhibit reduced viability but have very severe midline crossing defects in the central nervous system. The fly wild-type cDNA driven by T2A-Gal4 partially rescues both defects. Overexpression of the human reference ROBO1 with T2A-GAL4 is toxic and reduces viability, whereas the recessive p.S1522L variant is less toxic, suggesting that it is a partial loss-of-function allele. In contrast, the dominant variant in fly robo1 (p.D413G) affects protein localization, impairs axonal guidance activity and induces mild phototransduction defects, suggesting that it is a neomorphic allele. In summary, our studies expand the phenotypic spectrum associated with ROBO1 variant alleles.
| S-EPMC9402236 | biostudies-literature
Project description:We aimed to define a novel autosomal recessive neurodevelopmental disorder, characterize its clinical features, and identify the underlying genetic cause for this condition. Clinical and genetic data from affected individuals with neurological disorders were matched across families from five global sites. Here, we report five recessive CSPG4 (NM_001897) missense variants [three homozygous: c.A1370G (p.Asp457Gly), c.2627G>A (p.Arg876His) and c.3247C>A (p.Gln1083Lys), and two compound heterozygote: c.A1370G and c.5156A>G (p.Asp457Gly and p.Gln1719Arg) and c.658A>G and c.1220_1221delinsTG (p.(Thr220Ala and p.Pro407Leu)] by next-generation sequencing of five unrelated families with seven affected subjects. All subjects share a novel neurodevelopmental syndrome characterized by severe intellectual disability, global developmental delay, delayed ability to walk, speech and language delay, distinctive facial features, along with varying degrees of neurological impairment, including hypotonia, cerebellar hypoplasia, and/or seizures. All CSPG4 variants were predicted to be damaging using in silico tools, and three-dimensional molecular modeling suggested significant alterations in protein stability, compromising inter- and intra-molecular interactions. The impact on neurological and craniofacial development was analyzed in CRISPR/Cas9-mediated zebrafish models. CSPG4 variants affected notochord development, neuronal function, and cerebellar structure along with a disorganized head scaffold with anomalous skeletal and cartilage components. Two individuals metabolomics and crispant transcriptomics revealed significant perturbation of metabolites, extracellular matrix (ECM) regulating pathways, and genes previously described to cause mental retardation, dwarfism, and facial anomalies in humans. Our study links novel, rare, damaging variants of the ECM gene CSPG4 to a novel recessive Mendelian neurodevelopmental disorder in humans and supports the role of CSPG4 in early development.
2023-07-01 | GSE229401 | GEO
Project description:Integrator (INT) is an RNA polymerase II (RNAPII)-associated complex that was recently identified to have a broad role in both RNA processing and transcription regulation. INT has at least 14 subunits, but INT germline mutations causing human disease have not been reported. We identified mutations in the Integrator Complex Subunit 8 gene (INTS8) causing a rare neurodevelopmental syndrome. In patient cells we identified significant disturbance of gene expression and RNA processing. Also, we show that injection of ints8 oligonucleotide morpholinos into zebrafish embryos leads to prominent underdevelopment of the head demonstrating the evolutionary conserved requirement of INTS8 in brain development. RNA sequencing was carried out using RNA samples from fibroblasts from two individuals with germline bi-allelic INTS8 mutations and from two healthy individuals
2017-05-17 | E-GEOD-76878 | biostudies-arrayexpress
Project description:Polycomb group (PcG) proteins initiate the formation of repressed chromatin domains and regulate developmental gene expression. A mammalian PcG protein, Enhancer of Zeste homolog 2 (Ezh2), triggers transcriptional repression by catalyzing the addition of methyl groups onto lysine-27 of histone H3 (H3K27me2/3)1. This action facilitates the binding of other PcG proteins to histone H3 and compaction of chromatin. Interestingly, there exists a paralog of Ezh2, termed Ezh1, whose primary function remains unclear. Here, we provide evidence for genome-wide association of Ezh1 with active epigenetic marks, RNA polymerase II (PolII) and mRNA production. Ezh1 depletion reduced global PolII occupancy within gene bodies and resulted in delayed transcriptional activation during differentiation of skeletal muscle cells. Conversely, ectopic expression of wild-type Ezh1 led to premature gene activation and rescued PolII-elongation defects in Ezh1-depleted cells. Collectively, these findings reveal an unanticipated role of a PcG protein in promoting mRNA transcription. Examination of 3 different histone modifications, 3 modified forms of RNA polymerase II, Ezh1, Ezh2 and mRNA levels in a skeletal muscle cells at various developmental stages.
2011-11-23 | E-GEOD-25549 | biostudies-arrayexpress