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https://www.readbyqxmd.com/read/28331962/sex-combs-reduced-scr-regulatory-region-of-drosophila-revisited
#1
Juan M Calvo-Martín, Montserrat Papaceit, Carmen Segarra
The Hox gene Sex combs reduced (Scr) is responsible for the differentiation of the labial and prothoracic segments in Drosophila. Scr is expressed in several specific tissues throughout embryonic development, following a complex path that must be coordinated by an equally complex regulatory region. Although some cis-regulatory modules (CRMs) have been identified in the Scr regulatory region (~75 kb), there has been no detailed and systematic study of the distinct regulatory elements present within this region...
March 22, 2017: Molecular Genetics and Genomics: MGG
https://www.readbyqxmd.com/read/28329686/demethylated-hsatii-dna-and-hsatii-rna-foci-sequester-prc1-and-mecp2-into-cancer-specific-nuclear-bodies
#2
Lisa L Hall, Meg Byron, Dawn M Carone, Troy W Whitfield, Gayle P Pouliot, Andrew Fischer, Peter Jones, Jeanne B Lawrence
This study reveals that high-copy satellite II (HSATII) sequences in the human genome can bind and impact distribution of chromatin regulatory proteins and that this goes awry in cancer. In many cancers, master regulatory proteins form two types of cancer-specific nuclear bodies, caused by locus-specific deregulation of HSATII. DNA demethylation at the 1q12 mega-satellite, common in cancer, causes PRC1 aggregation into prominent Cancer-Associated Polycomb (CAP) bodies. These loci remain silent, whereas HSATII loci with reduced PRC1 become derepressed, reflecting imbalanced distribution of UbH2A on these and other PcG-regulated loci...
March 21, 2017: Cell Reports
https://www.readbyqxmd.com/read/28329683/inactivation-of-ezh2-upregulates-gfi1-and-drives-aggressive-myc-driven-group-3-medulloblastoma
#3
BaoHan T Vo, Chunliang Li, Marc A Morgan, Ilan Theurillat, David Finkelstein, Shaela Wright, Judith Hyle, Stephanie M C Smith, Yiping Fan, Yong-Dong Wang, Gang Wu, Brent A Orr, Paul A Northcott, Ali Shilatifard, Charles J Sherr, Martine F Roussel
The most aggressive of four medulloblastoma (MB) subgroups are cMyc-driven group 3 (G3) tumors, some of which overexpress EZH2, the histone H3K27 mono-, di-, and trimethylase of polycomb-repressive complex 2. Ezh2 has a context-dependent role in different cancers as an oncogene or tumor suppressor and retards tumor progression in a mouse model of G3 MB. Engineered deletions of Ezh2 in G3 MBs by gene editing nucleases accelerated tumorigenesis, whereas Ezh2 re-expression reversed attendant histone modifications and slowed tumor progression...
March 21, 2017: Cell Reports
https://www.readbyqxmd.com/read/28323035/naturally-occurring-anti-cancer-agents-targeting-ezh2
#4
Fahimeh Shahabipour, Michele Caraglia, Muhammed Majeed, Giuseppe Derosa, Pamela Maffioli, Amirhossein Sahebkar
Natural products are considered as promising tools for the prevention and treatment of cancer. The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase unit of polycomb repressor complexes such as PRC2 complex that has oncogenic roles through interference with growth and metastatic potential. Several agents targeting EZH2 has been discovered but they often induce side effects in clinical trials. Recently, EZH2 has emerged as a potential target of natural products with documented anti-cancer effects and this discloses a new scenario for the development of EZH2 inhibitory strategies with agents with low cytotoxic detrimental effects...
March 17, 2017: Cancer Letters
https://www.readbyqxmd.com/read/28320739/a-covalently-bound-inhibitor-triggers-ezh2-degradation-through-chip-mediated-ubiquitination
#5
Xu Wang, Wei Cao, Jianjun Zhang, Ming Yan, Qin Xu, Xiangbing Wu, Lixin Wan, Zhiyuan Zhang, Chenping Zhang, Xing Qin, Meng Xiao, Dongxia Ye, Yuyang Liu, Zeguang Han, Shaomeng Wang, Li Mao, Wenyi Wei, Wantao Chen
Enhancer of zeste homolog 2 (EZH2) has been characterized as a critical oncogene and a promising drug target in human malignant tumors. The current EZH2 inhibitors strongly suppress the enhanced enzymatic function of mutant EZH2 in some lymphomas. However, the recent identification of a PRC2- and methyltransferase-independent role of EZH2 indicates that a complete suppression of all oncogenic functions of EZH2 is needed. Here, we report a unique EZH2-targeting strategy by identifying a gambogenic acid (GNA) derivative as a novel agent that specifically and covalently bound to Cys668 within the EZH2-SET domain, triggering EZH2 degradation through COOH terminus of Hsp70-interacting protein (CHIP)-mediated ubiquitination...
March 20, 2017: EMBO Journal
https://www.readbyqxmd.com/read/28306504/targeting-of-polycomb-repressive-complex-2-to-rna-by-short-repeats-of-consecutive-guanines
#6
Xueyin Wang, Karen J Goodrich, Anne R Gooding, Haroon Naeem, Stuart Archer, Richard D Paucek, Daniel T Youmans, Thomas R Cech, Chen Davidovich
Polycomb repressive complex 2 (PRC2) is a histone methyltransferase that trimethylates H3K27, a mark of repressed chromatin. Mammalian PRC2 binds RNA promiscuously, with thousands of target transcripts in vivo. But what does PRC2 recognize in these RNAs? Here we show that purified human PRC2 recognizes G > C,U ≫ A in single-stranded RNA and has a high affinity for folded guanine quadruplex (G4) structures but little binding to duplex RNAs. Importantly, G-tract motifs are significantly enriched among PRC2-binding transcripts in vivo...
March 16, 2017: Molecular Cell
https://www.readbyqxmd.com/read/28304275/pcgf6-prc1-suppresses-premature-differentiation-of-mouse-embryonic-stem-cells-by-regulating-germ-cell-related-genes
#7
Mitsuhiro Endoh, Takaho A Endo, Jun Shinga, Katsuhiko Hayashi, Anca Farcas, Kit-Wan Ma, Shinsuke Ito, Jafar Sharif, Tamie Endoh, Naoko Onaga, Manabu Nakayama, Tomoyuki Ishikura, Osamu Masui, Benedikt M Kessler, Toshio Suda, Osamu Ohara, Akihiko Okuda, Robert J Klose, Haruhiko Koseki
The ring finger protein PCGF6 (polycomb group ring finger 6) interacts with RING1A/B and E2F6 associated factors to form a non-canonical PRC1 (polycomb repressive complex 1) known as PCGF6-PRC1. Here, we demonstrate that PCGF6-PRC1 plays a role in repressing a subset of PRC1 target genes by recruiting RING1B and mediating downstream mono-ubiquitination of histone H2A. PCGF6-PRC1 bound loci are highly enriched for promoters of germ cell-related genes in mouse embryonic stem cells (ESCs). Conditional ablation of Pcgf6 in ESCs leads to robust de-repression of such germ cell-related genes, in turn affecting cell growth and viability...
March 17, 2017: ELife
https://www.readbyqxmd.com/read/28302792/propagation-of-polycomb-repressed-chromatin-requires-sequence-specific-recruitment-to-dna
#8
Friederike Laprell, Katja Finkl, Jürg Müller
Epigenetic inheritance models posit that during Polycomb repression, Polycomb Repressive Complex 2 (PRC2) propagates histone H3K27 tri-methylation (H3K27me3) independently of DNA sequence. We show that insertion of Polycomb Response Element (PRE) DNA into the Drosophila genome creates extended domains of H3K27me3-modified nucleosomes in the flanking chromatin and causes repression of a linked reporter gene. After excision of PRE DNA, H3K27me3 nucleosomes become diluted with each round of DNA replication and reporter gene repression is lost, whereas in replication-stalled cells, H3K27me3 levels stay high and repression persists...
March 16, 2017: Science
https://www.readbyqxmd.com/read/28298433/re-evaluating-the-foundations-of-lncrna-polycomb-function
#9
Mario R Blanco, Mitchell Guttman
No abstract text is available yet for this article.
March 15, 2017: EMBO Journal
https://www.readbyqxmd.com/read/28288000/age-associated-chromatin-relaxation-is-enhanced-in-huntington-s-disease-mice
#10
Myungsun Park, Byungkuk Min, Kyuheum Jeon, Sunwha Cho, Jung Sun Park, Jisun Kim, Jeha Jeon, Jinhoi Song, Seokho Kim, Sangkyun Jeong, Hyemyung Seo, Yong-Kook Kang
Expansion of polyglutamine stretch in the huntingtin (HTT) protein is a major cause of Huntington's disease (HD). The polyglutamine part in HTT interacts with various proteins implicated in epigenetic regulation of genes, suggesting that mutant HTT may disturb the integrity of the epigenetic system. Here, we used a PCRseq-based method to examine expression profile of 395 exonic segments from 260 "epi-driver" genes in splenic T lymphocytes from aged HD mice. We identified 67 exonic segments differentially expressed between young and aged HD mice, most of them upregulated in the aged...
March 12, 2017: Aging
https://www.readbyqxmd.com/read/28285903/prc2-facilitates-the-regulatory-topology-required-for-poised-enhancer-function-during-pluripotent-stem-cell-differentiation
#11
Sara Cruz-Molina, Patricia Respuela, Christina Tebartz, Petros Kolovos, Milos Nikolic, Raquel Fueyo, Wilfred F J van Ijcken, Frank Grosveld, Peter Frommolt, Hisham Bazzi, Alvaro Rada-Iglesias
Poised enhancers marked by H3K27me3 in pluripotent stem cells have been implicated in the establishment of somatic expression programs during embryonic stem cell (ESC) differentiation. However, the functional relevance and mechanism of action of poised enhancers remain unknown. Using CRISPR/Cas9 technology to engineer precise genetic deletions, we demonstrate that poised enhancers are necessary for the induction of major anterior neural regulators. Interestingly, circularized chromosome conformation capture sequencing (4C-seq) shows that poised enhancers already establish physical interactions with their target genes in ESCs in a polycomb repressive complex 2 (PRC2)-dependent manner...
February 28, 2017: Cell Stem Cell
https://www.readbyqxmd.com/read/28281550/reduced-h3k27me3-expression-in-merkel-cell-polyoma-virus-positive-tumors
#12
Klaus J Busam, Melissa P Pulitzer, Daniel C Coit, Maria Arcila, Danielle Leng, Achim A Jungbluth, Thomas Wiesner
Merkel cell carcinoma is a primary cutaneous neuroendocrine carcinoma, which once metastatic is difficult to treat. Recent mutation analyses of Merkel cell carcinoma revealed a low number of mutations in Merkel cell polyomavirus-associated tumors, and a high number of mutations in virus-negative combined squamous cell and neuroendocrine carcinomas of chronically sun-damaged skin. We speculated that the paucity of mutations in virus-positive Merkel cell carcinoma may reflect a pathomechanism that depends on derangements of chromatin without alterations in the DNA sequence (epigenetic dysregulation)...
March 10, 2017: Modern Pathology: An Official Journal of the United States and Canadian Academy of Pathology, Inc
https://www.readbyqxmd.com/read/28273461/integrin-beta-3-regulates-cellular-senescence-by-activating-the-tgf-%C3%AE-pathway
#13
Valentina Rapisarda, Michela Borghesan, Veronica Miguela, Vesela Encheva, Ambrosius P Snijders, Amaia Lujambio, Ana O'Loghlen
Cellular senescence is an important in vivo mechanism that prevents the propagation of damaged cells. However, the precise mechanisms regulating senescence are not well characterized. Here, we find that ITGB3 (integrin beta 3 or β3) is regulated by the Polycomb protein CBX7. β3 expression accelerates the onset of senescence in human primary fibroblasts by activating the transforming growth factor β (TGF-β) pathway in a cell-autonomous and non-cell-autonomous manner. β3 levels are dynamically increased during oncogene-induced senescence (OIS) through CBX7 Polycomb regulation, and downregulation of β3 levels overrides OIS and therapy-induced senescence (TIS), independently of its ligand-binding activity...
March 7, 2017: Cell Reports
https://www.readbyqxmd.com/read/28270146/bmi1-a-new-target-of-ck2%C3%AE
#14
Soumyajit Banerjee Mustafi, Prabir Kumar Chakraborty, Shailendra Kumar Dhar Dwivedi, Kai Ding, Katherine M Moxley, Priyabrata Mukherjee, Resham Bhattacharya
BACKGROUND: The polycomb group protein, BMI1 plays important roles in chromatin modification, stem cell function, DNA damage repair and mitochondrial bioenergetics. Such diverse cellular functions of BMI1 could be, in part, due to post-translational modifications, especially phosphorylation. To date, AKT has been reported as a kinase that by site specific phosphorylation of BMI1 modulates its oncogenic functions. METHODS: Immunoprecipitation in conjunction with kinase assay and mass spectrometry was used to determine association with and site specific phosphorylation of BMI1 by CK2α...
March 7, 2017: Molecular Cancer
https://www.readbyqxmd.com/read/28263309/ezh2-is-a-potential-therapeutic-target-for-h3k27m-mutant-pediatric-gliomas
#15
Faizaan Mohammad, Simon Weissmann, Benjamin Leblanc, Deo P Pandey, Jonas W Højfeldt, Itys Comet, Chunqin Zheng, Jens Vilstrup Johansen, Nicolas Rapin, Bo T Porse, Andrey Tvardovskiy, Ole N Jensen, Nagore G Olaciregui, Cinzia Lavarino, Mariona Suñol, Carmen de Torres, Jaume Mora, Angel M Carcaboso, Kristian Helin
Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumor that is located in the pons and primarily affects children. Nearly 80% of DIPGs harbor mutations in histone H3 genes, wherein lysine 27 is substituted with methionine (H3K27M). H3K27M has been shown to inhibit polycomb repressive complex 2 (PRC2), a multiprotein complex responsible for the methylation of H3 at lysine 27 (H3K27me), by binding to its catalytic subunit EZH2. Although DIPGs with the H3K27M mutation show global loss of H3K27me3, several genes retain H3K27me3...
February 27, 2017: Nature Medicine
https://www.readbyqxmd.com/read/28263307/therapeutic-targeting-of-polycomb-and-bet-bromodomain-proteins-in-diffuse-intrinsic-pontine-gliomas
#16
Andrea Piunti, Rintaro Hashizume, Marc A Morgan, Elizabeth T Bartom, Craig M Horbinski, Stacy A Marshall, Emily J Rendleman, Quanhong Ma, Yoh-Hei Takahashi, Ashley R Woodfin, Alexander V Misharin, Nebiyu A Abshiru, Rishi R Lulla, Amanda M Saratsis, Neil L Kelleher, C David James, Ali Shilatifard
Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive pediatric brainstem tumor characterized by rapid and uniform patient demise. A heterozygous point mutation of histone H3 occurs in more than 80% of these tumors and results in a lysine-to-methionine substitution (H3K27M). Expression of this histone mutant is accompanied by a reduction in the levels of polycomb repressive complex 2 (PRC2)-mediated H3K27 trimethylation (H3K27me3), and this is hypothesized to be a driving event of DIPG oncogenesis...
February 27, 2017: Nature Medicine
https://www.readbyqxmd.com/read/28260023/silencing-bmi1-radiosensitizes-human-breast-cancer-cells-by-inducing-dna-damage-and-autophagy
#17
James Griffith, Daniel Andrade, Meghna Mehta, William Berry, Doris M Benbrook, Natarajan Aravindan, Terence S Herman, Rajagopal Ramesh, Anupama Munshi
Overexpression of BMI1 in human cancer cells, a member of the polycomb group of repressive complexes, correlates with advanced stage of disease, aggressive clinico-pathological behavior, poor prognosis, and resistance to radiation and chemotherapy. Studies have shown that experimental reduction of BMI1 protein level in tumor cells results in inhibition of cell proliferation, induction of apoptosis and/or senescence, and increased susceptibility to cytotoxic agents and radiation therapy. Although a role for BMI1 in cancer progression and its importance as a molecular target for cancer therapy has been established, information on the impact of silencing BMI1 in triple-negative breast cancer (TNBC) and its consequence on radiotherapy have not been well studied...
February 28, 2017: Oncology Reports
https://www.readbyqxmd.com/read/28257897/ezh2-regulates-spinal-neuroinflammation-in-rats-with-neuropathic-pain
#18
Ruchi Yadav, Han-Rong Weng
Alteration in gene expression along the pain signaling pathway is a key mechanism contributing to the genesis of neuropathic pain. Accumulating studies have shown that epigenetic regulation plays a crucial role in nociceptive process in the spinal dorsal horn. In this present study, we investigated the role of enhancer of zeste homolog-2 (EZH2), a subunit of the polycomb repressive complex 2, in the spinal dorsal horn in the genesis of neuropathic pain in rats induced by partial sciatic nerve ligation. EZH2 is a histone methyltransferase, which catalyzes the methylation of histone H3 on K27 (H3K27), resulting in gene silencing...
February 28, 2017: Neuroscience
https://www.readbyqxmd.com/read/28256832/allosteric-inactivation-of-polycomb-repressive-complex-2-prc2-by-inhibiting-its-adapter-protein-embryonic-ectodomain-development-eed
#19
Chao-Yie Yang, Shaomeng Wang
Aberrant PRC2 activity produces gene repressive epigenetic marks in multiple diseases and led to identification of Ezh2 as a drug target. Recent studies have shown that the epigenetic reader protein EED, associated with Ezh2 in PRC2, has an additional function to stimulate the PRC2 activity after binding to H3K27me3. Optimizing a compound known to block the H3K27me3 site in EED discovered by in-house screening, Novartis scientists have now produced a compound that shows durable tumor regression in a lymphoma xenograft model...
March 3, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28254491/ezh1-in-germ-cells-safeguards-the-function-of-prc2-during-spermatogenesis
#20
Weipeng Mu, Joshua Starmer, Yoichiro Shibata, Della Yee, Terry Magnuson
We previously reported the requirement of Polycomb Repressive Complex 2 (PRC2) for spermatogenesis through transcriptional repression of somatic genes and meiosis-specific genes. To characterize how PRC2's two methyltransferase subunits, EZH1 and EZH2, regulate histone H3 lysine 27 (H3K27) methylation during germ cell development, we generated mouse models with a germline ablation of EZH1 and/or EHZ2. Only the combined loss of EZH1 and EZH2 caused a depletion of global H3K27me3 marks and meiotic arrest in spermatocytes...
February 27, 2017: Developmental Biology
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