Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA219417 | ENA |
REPOSITORIES: ENA
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Project description:The symptoms of ataxia-telangiectasia (A-T) include a progressive neurodegeneration caused by ATM protein deficiency. We previously found that nuclear accumulation of histone deacetylase-4, HDAC4, contributes to this degeneration; we now report that increased histone H3K27 trimethylation (H3K27me3) mediated by polycomb repressive complex 2 (PRC2) also plays an important role in the A-T phenotype. Enhancer of zeste homolog 2 (EZH2), a core catalytic component of PRC2, is identified as a new ATM kinase target, and its S734 phosphorylation reduces protein stability. Thus, PRC2 formation is elevated along with H3K27me3in ATM deficiency. ChIP-sequencing shows a significant increase in H3K27me3 ‘marks’ and a dramatic shift in their location. The change of H3K27me3 chromatin-binding pattern is directly related to cell cycle re-entry and cell death of ATM-deficient neurons. Lentiviral knockdown of EZH2 rescues Purkinje cell degeneration and behavioral abnormalities in Atm / mice, demonstrating that EZH2-mediated H3K27me3 is another key factor in A-T neurodegeneration. Two samples each were run of brain total RNA from Atm+/+ and Atm-/- mice.
2013-10-25 | E-GEOD-50951 | biostudies-arrayexpress
Project description:The symptoms of ataxia-telangiectasia (A-T) include a progressive neurodegeneration caused by ATM protein deficiency. We previously found that nuclear accumulation of histone deacetylase-4, HDAC4, contributes to this degeneration; we now report that increased histone H3K27 trimethylation (H3K27me3) mediated by polycomb repressive complex 2 (PRC2) also plays an important role in the A-T phenotype. Enhancer of zeste homolog 2 (EZH2), a core catalytic component of PRC2, is identified as a new ATM kinase target, and its S734 phosphorylation reduces protein stability. Thus, PRC2 formation is elevated along with H3K27me3in ATM deficiency. ChIP-sequencing shows a significant increase in H3K27me3 ‘marks’ and a dramatic shift in their location. The change of H3K27me3 chromatin-binding pattern is directly related to cell cycle re-entry and cell death of ATM-deficient neurons. Lentiviral knockdown of EZH2 rescues Purkinje cell degeneration and behavioral abnormalities in Atm / mice, demonstrating that EZH2-mediated H3K27me3 is another key factor in A-T neurodegeneration.
2013-10-25 | GSE50951 | GEO
Project description:Trimethylation on H3K27 (H3K27me3) mediated by Polycomb repressive complex 2 (PRC2) has been linked to embryonic stem cell (ESC) identity and pluripotency. EZH2, the catalytic subunit of PRC2, has been reported as the sole histone methyltransferase that methylates H3K27 and mediates transcriptional silencing. Analysis of Ezh2(-/-) ESCs suggests existence of an additional enzyme(s) catalyzing H3K27 methylation. We have identified EZH1, a homolog of EZH2 that is physically present in a noncanonical PRC2 complex, as an H3K27 methyltransferase in vivo and in vitro. EZH1 colocalizes with the H3K27me3 mark on chromatin and preferentially preserves this mark on development-related genes in Ezh2(-/-) ESCs. Depletion of Ezh1 in cells lacking Ezh2 abolishes residual methylation on H3K27 and derepresses H3K27me3 target genes, demonstrating a role of EZH1 in safeguarding ESC identity. Ezh1 partially complements Ezh2 in executing pluripotency during ESC differentiation, suggesting that cell-fate transitions require epigenetic specificity.
2009-03-25 | GSE15388 | GEO
Project description:Histone methyltransferases (HMTases), as chromatin modifiers, regulate the transcriptomic landscape in normal development as well in diseases such as cancer. Here, we molecularly order two HMTases, EZH2 and MMSET that have established genetic links to oncogenesis. EZH2, which mediates histone H3K27 trimethylation and is associated with gene silencing, was shown to be coordinately expressed and function upstream of MMSET, which mediates H3K36 dimethylation and is associated with active transcription. We found that the EZH2-MMSET HMTase axis is coordinated by a microRNA network and that the oncogenic functions of EZH2 require MMSET activity. Together, these results suggest that the EZH2-MMSET HMTase axis coordinately functions as a master regulator of transcriptional repression, activation, and oncogenesis and may represent an attractive therapeutic target in cancer. Examination of H3K36me2 mark in control and stable EZH2 knockdown cells
2012-11-15 | E-GEOD-41652 | biostudies-arrayexpress
Project description:Histone methyltransferases (HMTases), as chromatin modifiers, regulate the transcriptomic landscape in normal development as well in diseases such as cancer. Here, we molecularly order two HMTases, EZH2 and MMSET that have established genetic links to oncogenesis. EZH2, which mediates histone H3K27 trimethylation and is associated with gene silencing, was shown to be coordinately expressed and function upstream of MMSET, which mediates H3K36 dimethylation and is associated with active transcription. We found that the EZH2-MMSET HMTase axis is coordinated by a microRNA network and that the oncogenic functions of EZH2 require MMSET activity. Together, these results suggest that the EZH2-MMSET HMTase axis coordinately functions as a master regulator of transcriptional repression, activation, and oncogenesis and may represent an attractive therapeutic target in cancer. LacZ control vs MMSET overexpression or MMSET DeltaSET overexpression in replicates
2012-11-15 | E-GEOD-41651 | biostudies-arrayexpress
Project description:Chemotherapy resistance is the main impediment in the treatment of acute myeloid leukaemia (AML). Despite rapid advances, the various mechanisms that lead to resistance development remain to be defined in detail. Here we report that loss-of-function mutations (LOF) in the histone methyltransferase EZH2 have the potential to confer resistance against the chemotherapeutic agent cytarabine. We identify seven distinct EZH2 mutations leading to loss of H3K27 trimethylation via multiple mechanisms. Analysis of matched diagnosis and relapse samples reveal a heterogenous regulation of EZH2 and a loss of EZH2 in 50% of patients. We confirm that loss of EZH2 induces resistance against cytarabine in the cell lines HEK293T and K562 as well as in a patient-derived xenograft (PDX) model. Proteomics and transcriptomics analysis reveal that resistance is conferred by upregulation of multiple direct and indirect EZH2 target genes that are involved in apoptosis evasion, augmentation of proliferation and alteration of transmembrane transporter function. Our data indicates, that loss of EZH2 results in upregulation of its target genes, providing the cell with a selective growth advantage, which mediates chemotherapy resistance.
2021-03-12 | PXD023139 | Pride
Project description:Enhancer of zeste homolog 2 (Ezh2) is the methyltransferase component of the Polycomb Repressive Complex 2 (PRC2), which is critical for trimethylation of histone 3 at lysine 27 (H3K27me3) and results in gene repression. Mutations in EZH2 and dysregulation of H3K27me3 can lead to neurodevelopmental abnormalities such as Weaver Syndrome and ataxia-telangiectasia. During cortical neurogenesis, H3K27me3 is a critical epigenetic modification that regulates cellular maturation rate, and in turn, determines when precursor cells exit the cell cycle. Loss of function studies reveal that Ezh2 plays a critical role in epigenetic regulation of neuronal fate and maturation in some brain regions, but a role for Ezh2 in forebrain GABAergic interneurons has not been explored. Here, we removed Ezh2 from the medial ganglionic eminence (MGE) to study its role in interneuron development.
2023-11-15 | GSE233190 | GEO
Project description:Enhancer of zeste homolog 2 (Ezh2) is the methyltransferase component of the Polycomb Repressive Complex 2 (PRC2), which is critical for trimethylation of histone 3 at lysine 27 (H3K27me3) and results in gene repression. Mutations in EZH2 and dysregulation of H3K27me3 can lead to neurodevelopmental abnormalities such as Weaver Syndrome and ataxia-telangiectasia. During cortical neurogenesis, H3K27me3 is a critical epigenetic modification that regulates cellular maturation rate, and in turn, determines when precursor cells exit the cell cycle. Loss of function studies reveal that Ezh2 plays a critical role in epigenetic regulation of neuronal fate and maturation in some brain regions, but a role for Ezh2 in forebrain GABAergic interneurons has not been explored. Here, we removed Ezh2 from the medial ganglionic eminence (MGE) to study its role in interneuron development.
2023-11-15 | GSE233152 | GEO
Project description:Enhancer of zeste homolog 2 (Ezh2) is the methyltransferase component of the Polycomb Repressive Complex 2 (PRC2), which is critical for trimethylation of histone 3 at lysine 27 (H3K27me3) and results in gene repression. Mutations in EZH2 and dysregulation of H3K27me3 can lead to neurodevelopmental abnormalities such as Weaver Syndrome and ataxia-telangiectasia. During cortical neurogenesis, H3K27me3 is a critical epigenetic modification that regulates cellular maturation rate, and in turn, determines when precursor cells exit the cell cycle. Loss of function studies reveal that Ezh2 plays a critical role in epigenetic regulation of neuronal fate and maturation in some brain regions, but a role for Ezh2 in forebrain GABAergic interneurons has not been explored. Here, we removed Ezh2 from the medial ganglionic eminence (MGE) to study its role in interneuron development.
2023-11-15 | GSE233151 | GEO
Project description:Background & Aims: Loss of ataxia-telangiectasia mutated, occurring in patients with multiple primary malignancies, including pancreatic cancer, is associated with poor prognosis. This study investigated the detailed molecular mechanism through which ataxia-telangiectasia mutated expression affects the prognosis of pancreatic-cancer patients Methods: Ataxia-telangiectasia mutated and phosphorylated ataxia-telangiectasia mutated levels in pancreatic-cancer patients who underwent surgical resection were analyzed using immunohistochemistry staining. RNA sequencing was performed on ataxia-telangiectasia mutated-knockdown pancreatic-cancer cells to elucidate the mechanism underlying the involvement of ataxia-telangiectasia mutated in pancreatic cancer. Results: Immunohistochemical analysis showed that 15.3% and 27.8% of clinical samples had low levels of ataxia-telangiectasia mutated and phosphorylated ataxia-telangiectasia mutated, respectively. Low phosphorylated ataxia-telangiectasia mutated expression substantially reduced overall and disease-free survival in pancreatic-cancer patients. Loss of ataxia-telangiectasia mutated promoted MET and NTN1 over-expression via hypoxia-inducible factor-1α, thereby enhancing pancreatic-cancer cell proliferation and migration. Conclusions: These results demonstrate that the loss of ataxia-telangiectasia mutated activates downstream proto-oncogenes, inhibits apoptosis, and promotes tumor growth; moreover, loss of phosphorylated ataxia-telangiectasia mutated leads to poor prognosis in pancreatic-cancer patients. Thus, ataxia-telangiectasia mutated may serve as a potential molecular marker to monitor patient prognosis and as a potential target for pancreatic cancer therapy
2023-02-13 | GSE224882 | GEO