scholarly journals H3 K27M and EZHIP impede H3K27-methylation spreading by inhibiting allosterically stimulated PRC2

2020 ◽  
Author(s):  
Siddhant U. Jain ◽  
Andrew Q. Rashoff ◽  
Samuel D. Krabbenhoft ◽  
Dominik Hoelper ◽  
Truman J. Do ◽  
...  
Keyword(s):  
Cpg Islands ◽  
Methyltransferase Activity ◽  
Polycomb Repressive Complex 2 ◽  
H3k27 Methylation ◽  
K27m Mutation ◽  
Mechanistic Insight ◽  
Competitive Inhibitors ◽  
Lysine Methyltransferase

AbstractDiffuse midline gliomas and posterior fossa type-A ependymomas contain the highly recurrent histone H3 K27M mutation and the H3 K27M-mimic EZHIP, respectively. In vitro, H3 K27M and EZHIP are competitive inhibitors of Polycomb Repressive Complex 2 (PRC2) lysine methyltransferase activity. In vivo, these proteins reduce overall H3K27me3 levels, however residual peaks of H3K27me3 remain at CpG islands through an unknown mechanism. Here, we report that EZHIP and H3 K27M preferentially interact with an allosterically activated form of PRC2 in vivo. The formation of H3 K27M- and EZHIP-PRC2 complexes occurs at CpG islands containing H3K27me3 and impedes PRC2 and H3K27me3 spreading. While EZHIP is not found outside of placental mammals, we find that expression of human EZHIP reduces H3K27me3 in Drosophila melanogaster through a conserved molecular mechanism. Our results highlight the mechanistic similarities between EZHIP and H3 K27M in vivo and provide mechanistic insight for the retention of residual H3K27me3 in tumors driven by these oncogenes.

scholarly journals PFA ependymoma-associated protein EZHIP inhibits PRC2 activity through a H3 K27M-like mechanism

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Siddhant U. Jain ◽  
Truman J. Do ◽  
Peder J. Lund ◽  
Andrew Q. Rashoff ◽  
Katharine L. Diehl ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
Cpg Islands ◽  
Inhibitory Protein ◽  
Allosteric Activation ◽  
Conserved Sequence ◽  
H3k27 Methylation ◽  
Necessary And Sufficient

Abstract Posterior fossa type A (PFA) ependymomas exhibit very low H3K27 methylation and express high levels of EZHIP (Enhancer of Zeste Homologs Inhibitory Protein, also termed CXORF67). Here we find that a conserved sequence in EZHIP is necessary and sufficient to inhibit PRC2 catalytic activity in vitro and in vivo. EZHIP directly contacts the active site of the EZH2 subunit in a mechanism similar to the H3 K27M oncohistone. Furthermore, expression of H3 K27M or EZHIP in cells promotes similar chromatin profiles: loss of broad H3K27me3 domains, but retention of H3K27me3 at CpG islands. We find that H3K27me3-mediated allosteric activation of PRC2 substantially increases the inhibition potential of EZHIP and H3 K27M, providing a mechanism to explain the observed loss of H3K27me3 spreading in tumors. Our data indicate that PFA ependymoma and DIPG are driven in part by the action of peptidyl PRC2 inhibitors, the K27M oncohistone and the EZHIP ‘oncohistone-mimic’, that dysregulate gene silencing to promote tumorigenesis.

scholarly journals PFA ependymoma-associated protein EZHIP inhibits PRC2 activity through a H3 K27M-like mechanism

2019 ◽  
Author(s):  
Siddhant U. Jain ◽  
Truman J. Do ◽  
Peder J. Lund ◽  
Andrew Q. Rashoff ◽  
Marcin Cieslik ◽  
...  
Keyword(s):  
Cpg Islands ◽  
Polycomb Group ◽  
Inhibitory Protein ◽  
Conserved Sequence ◽  
H3k27 Methylation ◽  
C Terminus ◽  
Diffuse Intrinsic Pontine Gliomas ◽  
Necessary And Sufficient

ABSTRACTPolycomb group (PcG) proteins are essential for development and are frequently misregulated in human cancers. Polycomb Repressive Complexes (PRC1, PRC2) function in a collaborative epigenetic cross-talk with H3K27me3 to initiate and maintain transcriptional silencing. Diffuse intrinsic pontine gliomas (DIPGs) have extremely low H3K27me3 levels mediated by H3 K27M oncohistone. Posterior fossa type A (PFA) ependymomas also exhibit very low H3K27 methylation but lack the K27M oncohistone. Instead, PFA tumors express high levels of EZHIP (Enhancer of Zeste Homologs Inhibitory Protein, also termed CXORF67). We find that a highly conserved sequence within the C-terminus of EZHIP is necessary and sufficient to inhibit the catalytic activity of PRC2 in vitro and in vivo. Our biochemical experiments indicate that EZHIP directly interacts with the active site of the EZH2 subunit in a mechanism that is remarkably similar to the K27M oncohistone. Furthermore, expression of H3 K27M or EZHIP in cells promote similar chromatin profiles: loss of broad H3K27me3 domains, but retention of H3K27me3 at the sites of PRC2 recruitment. Importantly, we find that H3K27me3-mediated allosteric activation of PRC2 substantially increases the inhibition potential of EZHIP and H3 K27M, providing a potential mechanism for loss of H3K27me3 spreading from CpG islands in vivo. Our data indicate that PFA ependymoma and DIPG are driven in part by the action of peptidyl PRC2 inhibitors– the K27M oncohistone and the EZHIP ‘oncohistone-mimic’– that dysregulate gene silencing to promote tumorigenesis.

scholarly journals PGC7 suppresses TET3 for protecting DNA methylation

2013 ◽  
Vol 42 (5) ◽  
pp. 2893-2905 ◽  
Author(s):  
Chunjing Bian ◽  
Xiaochun Yu
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanism ◽  
Biological Process ◽  
Cpg Islands ◽  
Binding Motifs ◽  
Genome Wide Analysis ◽  
Dna Motif ◽  
Genome Wide

Abstract Ten-eleven translocation (TET) family enzymes convert 5-methylcytosine to 5-hydroxylmethylcytosine. However, the molecular mechanism that regulates this biological process is not clear. Here, we show the evidence that PGC7 (also known as Dppa3 or Stella) interacts with TET2 and TET3 both in vitro and in vivo to suppress the enzymatic activity of TET2 and TET3. Moreover, lacking PGC7 induces the loss of DNA methylation at imprinting loci. Genome-wide analysis of PGC7 reveals a consensus DNA motif that is recognized by PGC7. The CpG islands surrounding the PGC7-binding motifs are hypermethylated. Taken together, our study demonstrates a molecular mechanism by which PGC7 protects DNA methylation from TET family enzyme-dependent oxidation.

scholarly journals Characterization of human gastric carcinoma-related methylation of 9 miR CpG islands and repression of their expressions in vitro and in vivo

BMC Cancer ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Yantao Du ◽  
Zhaojun Liu ◽  
Liankun Gu ◽  
Jing Zhou ◽  
Bu-dong Zhu ◽  
...  
Keyword(s):  
Gastric Carcinoma ◽  
Cpg Islands ◽  
Human Gastric Carcinoma

scholarly journals SARS-CoV-2 Spike triggers barrier dysfunction and vascular leak via integrins and TGF-β signaling

2021 ◽  
Author(s):  
Scott B Biering ◽  
Francielle Tramontini Gomes de Sousa ◽  
Laurentia V. Tjang ◽  
Felix Pahmeier ◽  
Richard Ruan ◽  
...  
Keyword(s):  
Transcriptional Response ◽  
Barrier Dysfunction ◽  
Vascular Leak ◽  
Endothelial Barrier Dysfunction ◽  
Mechanistic Insight ◽  
Starting Point ◽  
Signaling Axis ◽  
Insight Into

Severe COVID-19 is associated with epithelial and endothelial barrier dysfunction within the lung as well as in distal organs. While it is appreciated that an exaggerated inflammatory response is associated with barrier dysfunction, the triggers of this pathology are unclear. Here, we report that cell-intrinsic interactions between the Spike (S) glycoprotein of SARS-CoV-2 and epithelial/endothelial cells are sufficient to trigger barrier dysfunction in vitro and vascular leak in vivo, independently of viral replication and the ACE2 receptor. We identify an S-triggered transcriptional response associated with extracellular matrix reorganization and TGF-β signaling. Using genetic knockouts and specific inhibitors, we demonstrate that glycosaminoglycans, integrins, and the TGF-β signaling axis are required for S-mediated barrier dysfunction. Our findings suggest that S interactions with barrier cells are a contributing factor to COVID-19 disease severity and offer mechanistic insight into SARS-CoV-2 triggered vascular leak, providing a starting point for development of therapies targeting COVID-19 pathogenesis.

scholarly journals Protein lysine 43 methylation by EZH1 promotes AML1-ETO transcriptional repression in leukemia

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Liping Dou ◽  
Fei Yan ◽  
Jiuxia Pang ◽  
Dehua Zheng ◽  
Dandan Li ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Transcriptional Repression ◽  
Lysine Methylation ◽  
Post Translational Modification ◽  
Histone Lysine Methylation ◽  
Histone Lysine ◽  
Histone Lysine Methyltransferase ◽  
Lysine Methyltransferase

Abstract The oncogenic fusion protein AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequences, but blocks AML1-dependent transcription. Previous studies have shown that post-translational modification of AML1-ETO may play a role in its regulation. Here we report that AML1-ETO-positive patients, with high histone lysine methyltransferase Enhancer of zeste homolog 1 (EZH1) expression, show a worse overall survival than those with lower EZH1 expression. EZH1 knockdown impairs survival and proliferation of AML1-ETO-expressing cells in vitro and in vivo. We find that EZH1 WD domain binds to the AML1-ETO NHR1 domain and methylates AML1-ETO at lysine 43 (Lys43). This requires the EZH1 SET domain, which augments AML1-ETO-dependent repression of tumor suppressor genes. Loss of Lys43 methylation by point mutation or domain deletion impairs AML1-ETO-repressive activity. These findings highlight the role of EZH1 in non-histone lysine methylation, indicating that cooperation between AML1-ETO and EZH1 and AML1-ETO site-specific lysine methylation promote AML1-ETO transcriptional repression in leukemia.

scholarly journals Histone H3K23-specific acetylation by MORF is coupled to H3K14 acylation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Brianna J. Klein ◽  
Suk Min Jang ◽  
Catherine Lachance ◽  
Wenyi Mi ◽  
Jie Lyu ◽  
...  
Keyword(s):  
Posttranslational Modification ◽  
Memory Impairment ◽  
Target Genes ◽  
Epigenetic Mark ◽  
Mechanistic Insight ◽  
Genomic Analyses ◽  
Insight Into

Abstract Acetylation of histone H3K23 has emerged as an essential posttranslational modification associated with cancer and learning and memory impairment, yet our understanding of this epigenetic mark remains insufficient. Here, we identify the native MORF complex as a histone H3K23-specific acetyltransferase and elucidate its mechanism of action. The acetyltransferase function of the catalytic MORF subunit is positively regulated by the DPF domain of MORF (MORFDPF). The crystal structure of MORFDPF in complex with crotonylated H3K14 peptide provides mechanistic insight into selectivity of this epigenetic reader and its ability to recognize both histone and DNA. ChIP data reveal the role of MORFDPF in MORF-dependent H3K23 acetylation of target genes. Mass spectrometry, biochemical and genomic analyses show co-existence of the H3K23ac and H3K14ac modifications in vitro and co-occupancy of the MORF complex, H3K23ac, and H3K14ac at specific loci in vivo. Our findings suggest a model in which interaction of MORFDPF with acylated H3K14 promotes acetylation of H3K23 by the native MORF complex to activate transcription.

scholarly journals Deficiency of G9a Inhibits Cell Proliferation and Activates Autophagy via Transcriptionally Regulating c-Myc Expression in Glioblastoma

2020 ◽  
Vol 8 ◽  
Author(s):  
Xiao Xue Ke ◽  
Rui Zhang ◽  
Xi Zhong ◽  
Lei Zhang ◽  
Hongjuan Cui
Keyword(s):  
Cell Proliferation ◽  
Cyclin B1 ◽  
Luciferase Reporter ◽  
Cycle Arrest ◽  
Histone Lysine Methyltransferase ◽  
Lysine Methyltransferase ◽  
A Cell ◽  
Cell Proliferation Control

Glioblastoma is an aggressive and difficult to treat cancer. Recent data have emerged implicating that histone modification level may play a crucial role in glioma genesis. The histone lysine methyltransferase G9a is mainly responsible for the mono- and di-methylation of histone H3 lysine 9 (H3K9), whose overexpression is associated with a more aggressive phenotype in cancer. However, the detailed correlations between G9a and glioblastoma genesis remain to be further elucidated. Here, we show that G9a is essential for glioblastoma carcinogenesis and reveal a probable mechanism of it in cell proliferation control. We found that G9a was highly expressed in glioblastoma cells, and knockdown or inhibition of G9a significantly repressed cell proliferation and tumorigenesis ability both in vitro and in vivo. Besides, knockdown or inhibition of G9a led to a cell cycle arrest in G2 phase, as well as decreased the expression of CDK1, CDK2, Cyclin A2, and Cyclin B1, while it induced the activation of autophagy. Further investigation showed that G9a deficiency induced cell proliferation suppression, and activation of autophagy was rescued by overexpression of the full-length c-Myc. Chromatin immunoprecipitation (ChIP) assay showed that G9a was enriched on the −2267 to −1949 region of the c-Myc promoter in LN-229 cells and the −1949 to −1630 region of the c-Myc promoter in U-87 MG cells. Dual-luciferase reporter assay showed that c-Myc promoter activity was significantly reduced after knockdown or inhibition of G9a. Our study shows that G9a controls glioblastoma cell proliferation by transcriptionally modulating oncogene c-Myc and provides insight into the capabilities of G9a working as a potential therapeutic target in glioblastoma.

scholarly journals Signaling function of PRC2 is essential for TCR-driven T cell responses

2018 ◽  
Vol 215 (4) ◽  
pp. 1101-1113 ◽  
Author(s):  
Marc-Werner Dobenecker ◽  
Joon Seok Park ◽  
Jonas Marcello ◽  
Michael T. McCabe ◽  
Richard Gregory ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Therapeutic Potential ◽  
Cell Types ◽  
Polycomb Repressive Complex 2 ◽  
Histone Lysine Methyltransferases

Differentiation and activation of T cells require the activity of numerous histone lysine methyltransferases (HMT) that control the transcriptional T cell output. One of the most potent regulators of T cell differentiation is the HMT Ezh2. Ezh2 is a key enzymatic component of polycomb repressive complex 2 (PRC2), which silences gene expression by histone H3 di/tri-methylation at lysine 27. Surprisingly, in many cell types, including T cells, Ezh2 is localized in both the nucleus and the cytosol. Here we show the presence of a nuclear-like PRC2 complex in T cell cytosol and demonstrate a role of cytosolic PRC2 in T cell antigen receptor (TCR)–mediated signaling. We show that short-term suppression of PRC2 precludes TCR-driven T cell activation in vitro. We also demonstrate that pharmacological inhibition of PRC2 in vivo greatly attenuates the severe T cell–driven autoimmunity caused by regulatory T cell depletion. Our data reveal cytoplasmic PRC2 is one of the most potent regulators of T cell activation and point toward the therapeutic potential of PRC2 inhibitors for the treatment of T cell–driven autoimmune diseases.

scholarly journals A non-canonical monovalent zinc finger stabilizes the integration of Cfp1 into the H3K4 methyltransferase complex COMPASS

2019 ◽  
Author(s):  
Yidai Yang ◽  
Monika Joshi ◽  
Yoh-hei Takahashi ◽  
Zhibin Ning ◽  
Qianhui Qu ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Zinc Finger Protein ◽  
H3k4 Methylation ◽  
Methyltransferase Activity ◽  
Vitro Binding ◽  
New Type ◽  
High Level ◽  
In Cells

Abstract COMPlex ASsociating with SET1 (COMPASS) is a histone H3 Lys-4 methyltransferase that typically marks the promoter region of actively transcribed genes. COMPASS is a multi-subunit complex in which the catalytic unit, SET1, is required for H3K4 methylation. An important subunit known to regulate SET1 methyltransferase activity is the CxxC zinc finger protein 1 (Cfp1). Cfp1 binds to COMPASS and is critical to maintain high level of H3K4me3 in cells but the mechanisms underlying its stimulatory activity is poorly understood. In this study, we show that Cfp1 only modestly activates COMPASS methyltransferase activity in vitro. Binding of Cfp1 to COMPASS is in part mediated by a new type of monovalent zinc finger (ZnF). This ZnF interacts with the COMPASS’s subunits RbBP5 and disruption of this interaction blunts its methyltransferase activity in cells and in vivo. Collectively, our studies reveal that a novel form of ZnF on Cfp1 enables its integration into COMPASS and contributes to epigenetic signaling.

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