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Andersen KØ, Detlefsen S, Brusgaard K, Christesen HT. Well-differentiated G1 and G2 pancreatic neuroendocrine tumors: a meta-analysis of published expanded DNA sequencing data. Front Endocrinol (Lausanne) 2024; 15:1351624. [PMID: 38868744 PMCID: PMC11167081 DOI: 10.3389/fendo.2024.1351624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 05/02/2024] [Indexed: 06/14/2024] Open
Abstract
Introduction Well-differentiated pancreatic neuroendocrine tumors (PNETs) can be non-functional or functional, e.g. insulinoma and glucagonoma. The majority of PNETs are sporadic, but PNETs also occur in hereditary syndromes, primarily multiple endocrine neoplasia type 1 (MEN1). The Knudson hypothesis stated a second, somatic hit in MEN1 as the cause of PNETs of MEN1 syndrome. In the recent years, reports on genetic somatic events in both sporadic and hereditary PNETs have emerged, providing a basis for a more detailed molecular understanding of the pathophysiology. In this systematic review and meta-analysis, we made a collation and statistical analysis of aggregated frequent genetic alterations and potential driver events in human grade G1/G2 PNETs. Methods A systematic search was performed in concordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) reporting guidelines of 2020. A search in Pubmed for published studies using whole exome, whole genome, or targeted gene panel (+400 genes) sequencing of human G1/G2 PNETs was conducted at the 25th of September 2023. Fourteen datasets from published studies were included with data on 221 patients and 225 G1/G2 PNETs, which were divided into sporadic tumors, and hereditary tumors with pre-disposing germline variants, and tumors with unknown germline status. Further, non-functioning and functioning PNETs were distinguished into two groups for pathway evaluation. The collated genetical analyses were conducted using the 'maftools' R-package. Results Sporadic PNETs accounted 72.0% (162/225), hereditary PNETs 13.3% (30/225), unknown germline status 14.7% (33/225). The most frequently altered gene was MEN1, with somatic variants and copy number variations in overall 42% (95/225); hereditary PNETs (germline variations in MEN1, VHL, CHEK2, BRCA2, PTEN, CDKN1B, and/or MUTYH) 57% (16/30); sporadic PNETs 36% (58/162); unknown germline status 64% (21/33). The MEN1 point mutations/indels were distributed throughout MEN1. Overall, DAXX (16%, 37/225) and ATRX-variants (12%, 27/225) were also abundant with missense mutations clustered in mutational hotspots associated with histone binding, and translocase activity, respectively. DAXX mutations occurred more frequently in PNETs with MEN1 mutations, p<0.05. While functioning PNETs shared few variated genes, non-functioning PNETs had more recurrent variations in genes associated with the Phosphoinositide 3-kinase, Wnt, NOTCH, and Receptor Tyrosine Kinase-Ras signaling onco-pathways. Discussion The somatic genetic alterations in G1/G2 PNETs are diverse, but with distinct differences between sporadic vs. hereditary, and functional vs. non-functional PNETs. Increased understanding of the genetic alterations may lead to identification of more drivers and driver hotspots in the tumorigenesis in well-differentiated PNETs, potentially giving a basis for the identification of new drug targets. (Funded by Novo Nordisk Foundation, grant number NNF19OC0057915).
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Affiliation(s)
- Kirstine Øster Andersen
- Hans Christian Andersen Children’s Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Sönke Detlefsen
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Klaus Brusgaard
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Henrik Thybo Christesen
- Hans Christian Andersen Children’s Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense, Denmark
- Steno Diabetes Center Odense, Odense, Denmark
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2
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López-Garrido MP, Carrascosa-Romero MC, Montero-Hernández M, Ruiz-Almansa J, Sánchez-Sánchez F. Brief Report: Evidence of Autism Spectrum Disorder Caused by a Mutation in ATRX Gene: A Case Report. J Autism Dev Disord 2024; 54:379-388. [PMID: 35593993 DOI: 10.1007/s10803-022-05588-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2022] [Indexed: 11/29/2022]
Abstract
ATRX mutations are commonly associated with alpha-thalassaemia mental retardation syndrome (ATR-X syndrome) with a notable variable expressivity. This X-linked disorder is characterized by intellectual disability (ID) in a higher or lesser degree, in which the alpha-thalassaemia feature is not always present. Other phenotypic manifestations like facial dimorphism, hypotonia, microcephaly, skeletal abnormalities or urogenital malformations have been frequently observed in ATR-X syndrome. Herein, we report a missense ATRX mutation (Thr1621Met) in a patient with an autism spectrum disorder (ASD) diagnosis. Except for ID, no typical signs of ATR-X syndrome were found in the patient. These results confirm the extensive phenotypic variability associated to ATRX mutations and show the involvement of this gene in the ASD.
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Affiliation(s)
- María-Pilar López-Garrido
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | | | - Minerva Montero-Hernández
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | - Jesús Ruiz-Almansa
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | - Francisco Sánchez-Sánchez
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain.
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Tillotson R, Yan K, Ruston J, DeYoung T, Córdova A, Turcotte-Cardin V, Yee Y, Taylor C, Visuvanathan S, Babbs C, Ivakine EA, Sled JG, Nieman BJ, Picketts DJ, Justice MJ. A new mouse model of ATR-X syndrome carrying a common patient mutation exhibits neurological and morphological defects. Hum Mol Genet 2023; 32:2485-2501. [PMID: 37171606 PMCID: PMC10360390 DOI: 10.1093/hmg/ddad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/18/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
ATRX is a chromatin remodelling ATPase that is involved in transcriptional regulation, DNA damage repair and heterochromatin maintenance. It has been widely studied for its role in ALT-positive cancers, but its role in neurological function remains elusive. Hypomorphic mutations in the X-linked ATRX gene cause a rare form of intellectual disability combined with alpha-thalassemia called ATR-X syndrome in hemizygous males. Clinical features also include facial dysmorphism, microcephaly, short stature, musculoskeletal defects and genital abnormalities. As complete deletion of ATRX in mice results in early embryonic lethality, the field has largely relied on conditional knockout models to assess the role of ATRX in multiple tissues. Given that null alleles are not found in patients, a more patient-relevant model was needed. Here, we have produced and characterized the first patient mutation knock-in model of ATR-X syndrome, carrying the most common causative mutation, R246C. This is one of a cluster of missense mutations located in the chromatin-binding domain and disrupts its function. The knock-in mice recapitulate several aspects of the patient disorder, including craniofacial defects, microcephaly, reduced body size and impaired neurological function. They provide a powerful model for understanding the molecular mechanisms underlying ATR-X syndrome and testing potential therapeutic strategies.
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Affiliation(s)
- Rebekah Tillotson
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital/Headley Way, Oxford OX3 9DS, UK
| | - Keqin Yan
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Julie Ruston
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Taylor DeYoung
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
| | - Alex Córdova
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Valérie Turcotte-Cardin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Yohan Yee
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Christine Taylor
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Shagana Visuvanathan
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Christian Babbs
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital/Headley Way, Oxford OX3 9DS, UK
| | - Evgueni A Ivakine
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - John G Sled
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Translational Medicine Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Brian J Nieman
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Translational Medicine Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - David J Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Monica J Justice
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A1, Canada
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Aguilera P, López-Contreras AJ. ATRX, a guardian of chromatin. Trends Genet 2023; 39:505-519. [PMID: 36894374 DOI: 10.1016/j.tig.2023.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 03/09/2023]
Abstract
ATRX (alpha-thalassemia mental retardation X-linked) is one of the most frequently mutated tumor suppressor genes in human cancers, especially in glioma, and recent findings indicate roles for ATRX in key molecular pathways, such as the regulation of chromatin state, gene expression, and DNA damage repair, placing ATRX as a central player in the maintenance of genome stability and function. This has led to new perspectives about the functional role of ATRX and its relationship with cancer. Here, we provide an overview of ATRX interactions and molecular functions and discuss the consequences of its impairment, including alternative lengthening of telomeres and therapeutic vulnerabilities that may be exploited in cancer cells.
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Affiliation(s)
- Paula Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Sevilla - Universidad Pablo de Olavide, Seville, Spain.
| | - Andrés J López-Contreras
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Sevilla - Universidad Pablo de Olavide, Seville, Spain.
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5
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Bieluszewska A, Wulfridge P, Doherty J, Ren W, Sarma K. ATRX histone binding and helicase activities have distinct roles in neuronal differentiation. Nucleic Acids Res 2022; 50:9162-9174. [PMID: 35998910 PMCID: PMC9458459 DOI: 10.1093/nar/gkac683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 12/24/2022] Open
Abstract
ATRX is a chromatin remodeler, which is mutated in ATRX syndrome, a neurodevelopmental disorder. ATRX mutations that alter histone binding or chromatin remodeling activities cluster in the PHD finger or the helicase domain respectively. Using engineered mouse embryonic stem cells that exclusively express ATRX protein with mutations in the PHD finger (PHDmut) or helicase domains (K1584R), we examine how specific ATRX mutations affect neurodifferentiation. ATRX PHDmut and K1584R proteins interact with the DAXX histone chaperone but show reduced localization to pericentromeres. Neurodifferentiation is both delayed and compromised in PHDmut and K1584R, and manifest differently from complete ATRX loss. We observe reduced enrichment of PHDmut protein to ATRX targets, while K1584R accumulates at these sites. Interestingly, ATRX mutations have distinct effects on the genome-wide localization of the polycomb repressive complex 2 (PRC2), with PHDmut and ATRX knockout showing reduced PRC2 binding at polycomb targets and K1584R showing loss at some sites and gains at others. Notably, each mutation associated with unique gene signatures, suggesting distinct pathways leading to impaired neurodifferentiation. Our results indicate that the histone binding and chromatin remodeling functions of ATRX play non-redundant roles in neurodevelopment, and when mutated lead to ATRX syndrome through separate regulatory pathways.
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Affiliation(s)
- Anna Bieluszewska
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA,Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Phillip Wulfridge
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA,Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John Doherty
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA,Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenqing Ren
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA,Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kavitha Sarma
- To whom correspondence should be addressed. Tel: +1 215 898 3970;
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6
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van Gerven MR, Bozsaky E, Matser YAH, Vosseberg J, Taschner-Mandl S, Koster J, Tytgat GAM, Molenaar JJ, van den Boogaard M. The mutational spectrum of ATRX aberrations in neuroblastoma and the associated patient and tumor characteristics. Cancer Sci 2022; 113:2167-2178. [PMID: 35384159 PMCID: PMC9207354 DOI: 10.1111/cas.15363] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/18/2022] [Accepted: 04/02/2022] [Indexed: 11/30/2022] Open
Abstract
Neuroblastoma is the most common extracranial solid tumor in children. The chromatin remodeler ATRX is frequently mutated in high‐risk patients with a poor prognosis. Although many studies have reported ATRX aberrations and the associated clinical characteristics in neuroblastoma, a comprehensive overview is currently lacking. In this study, we extensively characterize the mutational spectrum of ATRX aberrations in neuroblastoma tumors reported in previous studies and present an overview of patient and tumor characteristics. We collected the data of a total of 127 neuroblastoma patients and three cell lines with ATRX aberrations originating from 20 papers. We subdivide the ATRX aberrations into nonsense, missense, and multiexon deletions (MEDs) and show that 68% of them are MEDs. Of these MEDs, 75% are predicted to be in‐frame. Furthermore, we identify a missense mutational hotspot region in the helicase domain. We also confirm that all three ATRX mutation types are more often identified in patients diagnosed at an older age, but still approximately 40% of the patients are aged 5 years or younger at diagnosis. Surprisingly, we found that 11q deletions are enriched in neuroblastomas with ATRX deletions compared to a reference cohort, but not in neuroblastomas with ATRX point mutations. Taken together, our data emphasizes a distinct ATRX mutation spectrum in neuroblastoma, which should be considered when studying molecular phenotypes and therapeutic strategies.
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Affiliation(s)
| | - Eva Bozsaky
- Tumor biology group, St Anna Children's Cancer Research Institute, Vienna, Austria
| | - Yvette A H Matser
- Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands
| | - Julian Vosseberg
- Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | | | - Jan Koster
- Department of Oncogenomics, Amsterdam UMC, location AMC, Amsterdam, the Netherlands
| | | | - Jan J Molenaar
- Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.,Department of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, the Netherlands
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7
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Wen T, Chen QY. Dynamic Activity of Histone H3-Specific Chaperone Complexes in Oncogenesis. Front Oncol 2022; 11:806974. [PMID: 35087762 PMCID: PMC8786718 DOI: 10.3389/fonc.2021.806974] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022] Open
Abstract
Canonical histone H3.1 and variant H3.3 deposit at different sites of the chromatin via distinct histone chaperones. Histone H3.1 relies on chaperone CAF-1 to mediate replication-dependent nucleosome assembly during S-phase, while H3.3 variant is regulated and incorporated into the chromatin in a replication-independent manner through HIRA and DAXX/ATRX. Current literature suggests that dysregulated expression of histone chaperones may be implicated in tumor progression. Notably, ectopic expression of CAF-1 can promote a switch between canonical H3.1 and H3 variants in the chromatin, impair the chromatic state, lead to chromosome instability, and impact gene transcription, potentially contributing to carcinogenesis. This review focuses on the chaperone proteins of H3.1 and H3.3, including structure, regulation, as well as their oncogenic and tumor suppressive functions in tumorigenesis.
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Affiliation(s)
- Ting Wen
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Qiao Yi Chen
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
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8
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Proximity labeling identifies a repertoire of site-specific R-loop modulators. Nat Commun 2022; 13:53. [PMID: 35013239 PMCID: PMC8748879 DOI: 10.1038/s41467-021-27722-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 12/06/2021] [Indexed: 11/11/2022] Open
Abstract
R-loops are three-stranded nucleic acid structures that accumulate on chromatin in neurological diseases and cancers and contribute to genome instability. Using a proximity-dependent labeling system, we identified distinct classes of proteins that regulate R-loops in vivo through different mechanisms. We show that ATRX suppresses R-loops by interacting with RNAs and preventing R-loop formation. Our proteomics screen also discovered an unexpected enrichment for proteins containing zinc fingers and homeodomains. One of the most consistently enriched proteins was activity-dependent neuroprotective protein (ADNP), which is frequently mutated in ASD and causal in ADNP syndrome. We find that ADNP resolves R-loops in vitro and that it is necessary to suppress R-loops in vivo at its genomic targets. Furthermore, deletion of the ADNP homeodomain severely diminishes R-loop resolution activity in vitro, results in R-loop accumulation at ADNP targets, and compromises neuronal differentiation. Notably, patient-derived human induced pluripotent stem cells that contain an ADNP syndrome-causing mutation exhibit R-loop and CTCF accumulation at ADNP targets. Our findings point to a specific role for ADNP-mediated R-loop resolution in physiological and pathological neuronal function and, more broadly, to a role for zinc finger and homeodomain proteins in R-loop regulation, with important implications for developmental disorders and cancers. R-loops are three-stranded nucleic acid structures that contribute to genome instability and accumulate in neurological diseases. Here the authors identify R-loop proximal factors, which are enriched for zinc finger and homeodomain proteins, including activity-dependent neuroprotective protein (ADNP). ADNP plays a role in R-loop resolution and loss-of-function leads to R-loop accumulation.
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9
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Bjarnason S, Ruidiaz SF, McIvor J, Mercadante D, Heidarsson PO. Protein intrinsic disorder on a dynamic nucleosomal landscape. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:295-354. [PMID: 34656332 DOI: 10.1016/bs.pmbts.2021.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The complex nucleoprotein landscape of the eukaryotic cell nucleus is rich in dynamic proteins that lack a stable three-dimensional structure. Many of these intrinsically disordered proteins operate directly on the first fundamental level of genome compaction: the nucleosome. Here we give an overview of how disordered interactions with and within nucleosomes shape the dynamics, architecture, and epigenetic regulation of the genetic material, controlling cellular transcription patterns. We highlight experimental and computational challenges in the study of protein disorder and illustrate how integrative approaches are increasingly unveiling the fine details of nuclear interaction networks. We finally dissect sequence properties encoded in disordered regions and assess common features of disordered nucleosome-binding proteins. As drivers of many critical biological processes, disordered proteins are integral to a comprehensive molecular view of the dynamic nuclear milieu.
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Affiliation(s)
- Sveinn Bjarnason
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland
| | - Sarah F Ruidiaz
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland
| | - Jordan McIvor
- School of Chemical Science, University of Auckland, Auckland, New Zealand
| | - Davide Mercadante
- School of Chemical Science, University of Auckland, Auckland, New Zealand.
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland.
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Teng YC, Sundaresan A, O'Hara R, Gant VU, Li M, Martire S, Warshaw JN, Basu A, Banaszynski LA. ATRX promotes heterochromatin formation to protect cells from G-quadruplex DNA-mediated stress. Nat Commun 2021; 12:3887. [PMID: 34162889 PMCID: PMC8222256 DOI: 10.1038/s41467-021-24206-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 06/07/2021] [Indexed: 12/15/2022] Open
Abstract
ATRX is a tumor suppressor that has been associated with protection from DNA replication stress, purportedly through resolution of difficult-to-replicate G-quadruplex (G4) DNA structures. While several studies demonstrate that loss of ATRX sensitizes cells to chemical stabilizers of G4 structures, the molecular function of ATRX at G4 regions during replication remains unknown. Here, we demonstrate that ATRX associates with a number of the MCM replication complex subunits and that loss of ATRX leads to G4 structure accumulation at newly synthesized DNA. We show that both the helicase domain of ATRX and its H3.3 chaperone function are required to protect cells from G4-induced replicative stress. Furthermore, these activities are upstream of heterochromatin formation mediated by the histone methyltransferase, ESET, which is the critical molecular event that protects cells from G4-mediated stress. In support, tumors carrying mutations in either ATRX or ESET show increased mutation burden at G4-enriched DNA sequences. Overall, our study provides new insights into mechanisms by which ATRX promotes genome stability with important implications for understanding impacts of its loss on human disease.
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Affiliation(s)
- Yu-Ching Teng
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Aishwarya Sundaresan
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ryan O'Hara
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Vincent U Gant
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Minhua Li
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sara Martire
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jane N Warshaw
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Amrita Basu
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Laura A Banaszynski
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Medical Center Research Institute, Harold. C. Simmons Comprehensive Cancer Center, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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11
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Darmusey L, Pérot G, Thébault N, Le Guellec S, Desplat N, Gaston L, Delespaul L, Lesluyes T, Darbo E, Gomez-Brouchet A, Richard E, Baud J, Leroy L, Coindre JM, Blay JY, Chibon F. ATRX Alteration Contributes to Tumor Growth and Immune Escape in Pleomorphic Sarcomas. Cancers (Basel) 2021; 13:2151. [PMID: 33946962 PMCID: PMC8124877 DOI: 10.3390/cancers13092151] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 12/17/2022] Open
Abstract
Whole genome and transcriptome sequencing of a cohort of 67 leiomyosarcomas has been revealed ATRX to be one of the most frequently mutated genes in leiomyosarcomas after TP53 and RB1. While its function is well described in the alternative lengthening of telomeres mechanism, we wondered whether its alteration could have complementary effects on sarcoma oncogenesis. ATRX alteration is associated with the down-expression of genes linked to differentiation in leiomyosarcomas, and to immunity in an additional cohort of 60 poorly differentiated pleomorphic sarcomas. In vitro and in vivo models showed that ATRX down-expression increases tumor growth rate and immune escape by decreasing the immunity load of active mast cells in sarcoma tumors. These data indicate that an alternative to unsuccessful targeting of the adaptive immune system in sarcoma could target the innate system. This might lead to a better outcome for sarcoma patients in terms of ATRX status.
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Affiliation(s)
- Lucie Darmusey
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
- University of Toulouse 3, Paul Sabatier, 31000 Toulouse, France
| | - Gaëlle Pérot
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- Centre Hospitalier Universitaire (CHU) de Toulouse, IUCT-Oncopole, 31000 Toulouse, France
| | - Noémie Thébault
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
| | - Sophie Le Guellec
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
| | - Nelly Desplat
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
| | - Laëtitia Gaston
- CHU de Bordeaux, Department of Medical Genetics, 33000 Bordeaux, France;
| | - Lucile Delespaul
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- University of Bordeaux, 33000 Bordeaux, France
| | - Tom Lesluyes
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- University of Bordeaux, 33000 Bordeaux, France
| | - Elodie Darbo
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
- University of Bordeaux, 33000 Bordeaux, France
- CNRS UMR5800, LaBRI, 33400 Talence, France
| | - Anne Gomez-Brouchet
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
- Centre Hospitalier Universitaire (CHU) de Toulouse, IUCT-Oncopole, 31000 Toulouse, France
| | - Elodie Richard
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
| | - Jessica Baud
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
| | - Laura Leroy
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
| | - Jean-Michel Coindre
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
- Institut Bergonie, Department of Pathology, 33000 Bordeaux, France
| | - Jean-Yves Blay
- Centre Léon Bérard, Department of Medical Oncology, 69000 Lyon, France;
- Inserm U1052, CNRS 5286, Cancer Research Center of Lyon, University Claude Bernard Lyon 1, 69000 Lyon, France
| | - Frédéric Chibon
- INSERM U1037, Cancer Research Center in Toulouse (CRCT), OncoSarc, 31000 Toulouse, France; (L.D.); (G.P.); (N.T.); (S.L.G.); (L.D.); (T.L.); (A.G.-B.); (L.L.)
- IUCT-Oncopole, Institut Claudius Régaud, Department of Pathology, 31000 Toulouse, France
- Inserm UMR1218, Action, Institut Bergonié, 33000 Bordeaux, France; (N.D.); (E.D.); (E.R.); (J.B.); (J.-M.C.)
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12
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Wheeler DA, Takebe N, Hinoue T, Hoadley KA, Cardenas MF, Hamilton AM, Laird PW, Wang L, Johnson A, Dewal N, Miller V, Piñeyro D, Castro de Moura M, Esteller M, Shen H, Zenklusen JC, Tarnuzzer R, McShane LM, Tricoli JV, Williams PM, Lubensky I, O'Sullivan-Coyne G, Kohn EC, Little RF, White J, Malik S, Harris L, Weil C, Chen AP, Karlovich C, Rodgers B, Shankar L, Jacobs P, Nolan T, Hu J, Muzny DM, Doddapaneni H, Korchina V, Gastier-Foster J, Bowen J, Leraas K, Edmondson EF, Doroshow JH, Conley BA, Ivy SP, Staudt LM. Molecular Features of Cancers Exhibiting Exceptional Responses to Treatment. Cancer Cell 2021; 39:38-53.e7. [PMID: 33217343 PMCID: PMC8478080 DOI: 10.1016/j.ccell.2020.10.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/23/2020] [Accepted: 10/13/2020] [Indexed: 12/21/2022]
Abstract
A small fraction of cancer patients with advanced disease survive significantly longer than patients with clinically comparable tumors. Molecular mechanisms for exceptional responses to therapy have been identified by genomic analysis of tumor biopsies from individual patients. Here, we analyzed tumor biopsies from an unbiased cohort of 111 exceptional responder patients using multiple platforms to profile genetic and epigenetic aberrations as well as the tumor microenvironment. Integrative analysis uncovered plausible mechanisms for the therapeutic response in nearly a quarter of the patients. The mechanisms were assigned to four broad categories-DNA damage response, intracellular signaling, immune engagement, and genetic alterations characteristic of favorable prognosis-with many tumors falling into multiple categories. These analyses revealed synthetic lethal relationships that may be exploited therapeutically and rare genetic lesions that favor therapeutic success, while also providing a wealth of testable hypotheses regarding oncogenic mechanisms that may influence the response to cancer therapy.
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Affiliation(s)
- David A Wheeler
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Naoko Takebe
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Katherine A Hoadley
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Maria F Cardenas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alina M Hamilton
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Linghua Wang
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | | | - Ninad Dewal
- Foundation Medicine Inc, Cambridge, MA 02141, USA
| | | | - David Piñeyro
- Josep Carreras Leukaemia Research Institute, Badalona, 08916 Barcelona, Catalonia, Spain; Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain
| | - Manuel Castro de Moura
- Josep Carreras Leukaemia Research Institute, Badalona, 08916 Barcelona, Catalonia, Spain
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute, Badalona, 08916 Barcelona, Catalonia, Spain; Centro de Investigacion Biomedica en Red Cancer (CIBERONC), 28029 Madrid, Spain; Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain; Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona (UB), 08007 Barcelona, Catalonia, Spain
| | - Hui Shen
- Van Andel Institute, Grand Rapids, MI 49503, USA
| | | | - Roy Tarnuzzer
- Center for Cancer Genomics, National Cancer Institute, Bethesda, MD 20892, USA
| | - Lisa M McShane
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - James V Tricoli
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Paul M Williams
- Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Irina Lubensky
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Elise C Kohn
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Richard F Little
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Jeffrey White
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Shakun Malik
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Lyndsay Harris
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Carol Weil
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Alice P Chen
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Chris Karlovich
- Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Brian Rodgers
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Lalitha Shankar
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Paula Jacobs
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Tracy Nolan
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Jianhong Hu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Viktoriya Korchina
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Jay Bowen
- Nationwide Children's Hospital, Columbus, OH 43205, USA
| | | | - Elijah F Edmondson
- Pathology and Histology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, NIH, Frederick, MD 21701, USA
| | - James H Doroshow
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Barbara A Conley
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - S Percy Ivy
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Louis M Staudt
- Center for Cancer Genomics, National Cancer Institute, Bethesda, MD 20892, USA.
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13
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Abstract
Neuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system and one of the most common solid tumors in infancy. Amplification of MYCN, copy number alterations, numerical and segmental chromosomal aberrations, mutations, and rearrangements on a handful of genes, such as ALK, ATRX, TP53, RAS/MAPK pathway genes, and TERT, are attributed as underlying causes that give rise to NB. However, the heterogeneous nature of the disease-along with the relative paucity of recurrent somatic mutations-reinforces the need to understand the interplay of genetic factors and epigenetic alterations in the context of NB. Epigenetic mechanisms tightly control gene expression, embryogenesis, imprinting, chromosomal stability, and tumorigenesis, thereby playing a pivotal role in physio- and pathological settings. The main epigenetic alterations include aberrant DNA methylation, disrupted patterns of posttranslational histone modifications, alterations in chromatin composition and/or architecture, and aberrant expression of non-coding RNAs. DNA methylation and demethylation are mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins, respectively, while histone modifications are coordinated by histone acetyltransferases and deacetylases (HATs, HDACs), and histone methyltransferases and demethylases (HMTs, HDMs). This article focuses predominately on the crosstalk between the epigenome and NB, and the implications it has on disease diagnosis and treatment.
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14
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Stabile M, Colavito D, Del Giudice E, Rispoli AF, Ingenito MC, Naumova AK. A novel exomal ATRX mutation with preferential transmission to offspring: A case report and review of the literature for transmission ratio distortion in ATRX families. Mol Med Rep 2020; 22:4561-4566. [PMID: 33173999 PMCID: PMC7646821 DOI: 10.3892/mmr.2020.11574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/21/2020] [Indexed: 12/19/2022] Open
Abstract
The present case report describes an Italian family with three affected probands, who exhibited serious mental disability, which has not been associated with other anomalies, except with slight facial dysmorphism. Molecular multigenic analysis for intellectual disability identified a previously unreported variant, p.Ile1765Met (c.5295C>G) in the SNF domain of the ATRX protein (in exon 24). The identified mutation was found in a hemizygous state in all three affected probands and in a heterozygous state in the asymptomatic mother and the female sibling. With respect to the phenotypic similarities found in the patients with those described in previous studies, the consistency in the mode of inheritance and segregation of the mutation, the variant reported in the present case report may be considered as ‘likely pathogenic’. To investigate the hypothesis that the preferential transmission of the ATRX mutation observed in this family reflected a general trend, a meta-analysis into the segregation of ATRX mutations from published pedigrees, following allelic transmission from mothers who are heterozygous carriers to their offspring, was performed. A preferential transmission of the mutant allele to male offspring (58% of males inherited the mutant allele) was found; however, the bias was not statistically significant (P=0.29; χ2 test).
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Affiliation(s)
- Mariano Stabile
- Zygote Center, Center for Genetics, Prenatal Diagnosis, Fertility, I-84131 Salerno, Italy
| | - Davide Colavito
- Research & Innovation s.r.l. (R&I Genetics), I-35127 Padova, Italy
| | - Elda Del Giudice
- Research & Innovation s.r.l. (R&I Genetics), I-35127 Padova, Italy
| | - Anna F Rispoli
- Zygote Center, Center for Genetics, Prenatal Diagnosis, Fertility, I-84131 Salerno, Italy
| | - Marina C Ingenito
- Zygote Center, Center for Genetics, Prenatal Diagnosis, Fertility, I-84131 Salerno, Italy
| | - Anna K Naumova
- Departments of Obstetrics and Gynecology and Human Genetics, Research Institute of the McGill University Health Centre (RI-MUHC), McGill University, Montreal, Quebec H4A 3J1, Canada
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15
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Asamitsu S, Yabuki Y, Ikenoshita S, Wada T, Shioda N. Pharmacological prospects of G-quadruplexes for neurological diseases using porphyrins. Biochem Biophys Res Commun 2020; 531:51-55. [DOI: 10.1016/j.bbrc.2020.01.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/26/2019] [Accepted: 01/09/2020] [Indexed: 12/14/2022]
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16
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Timpano S, Picketts DJ. Neurodevelopmental Disorders Caused by Defective Chromatin Remodeling: Phenotypic Complexity Is Highlighted by a Review of ATRX Function. Front Genet 2020; 11:885. [PMID: 32849845 PMCID: PMC7432156 DOI: 10.3389/fgene.2020.00885] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 07/20/2020] [Indexed: 12/15/2022] Open
Abstract
The ability to determine the genetic etiology of intellectual disability (ID) and neurodevelopmental disorders (NDD) has improved immensely over the last decade. One prevailing metric from these studies is the large percentage of genes encoding epigenetic regulators, including many members of the ATP-dependent chromatin remodeling enzyme family. Chromatin remodeling proteins can be subdivided into five classes that include SWI/SNF, ISWI, CHD, INO80, and ATRX. These proteins utilize the energy from ATP hydrolysis to alter nucleosome positioning and are implicated in many cellular processes. As such, defining their precise roles and contributions to brain development and disease pathogenesis has proven to be complex. In this review, we illustrate that complexity by reviewing the roles of ATRX on genome stability, replication, and transcriptional regulation and how these mechanisms provide key insight into the phenotype of ATR-X patients.
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Affiliation(s)
- Sara Timpano
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - David J. Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
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17
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Amato R, Valenzuela M, Berardinelli F, Salvati E, Maresca C, Leone S, Antoccia A, Sgura A. G-quadruplex Stabilization Fuels the ALT Pathway in ALT-positive Osteosarcoma Cells. Genes (Basel) 2020; 11:genes11030304. [PMID: 32183119 PMCID: PMC7140816 DOI: 10.3390/genes11030304] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/20/2020] [Accepted: 03/09/2020] [Indexed: 12/20/2022] Open
Abstract
Most human tumors maintain telomere lengths by telomerase, whereas a portion of them (10–15%) uses a mechanism named alternative lengthening of telomeres (ALT). The telomeric G-quadruplex (G4) ligand RHPS4 is known for its potent antiproliferative effect, as shown in telomerase-positive cancer models. Moreover, RHPS4 is also able to reduce cell proliferation in ALT cells, although the influence of G4 stabilization on the ALT mechanism has so far been poorly investigated. Here we show that sensitivity to RHPS4 is comparable in ALT-positive (U2OS; SAOS-2) and telomerase-positive (HOS) osteosarcoma cell lines, unlinking the telomere maintenance mechanism and RHPS4 responsiveness. To investigate the impact of G4 stabilization on ALT, the cardinal ALT hallmarks were analyzed. A significant induction of telomeric doublets, telomeric clusterized DNA damage, ALT-associated Promyelocytic Leukaemia-bodies (APBs), telomere sister chromatid exchanges (T-SCE) and c-circles was found exclusively in RHPS4-treated ALT cells. We surmise that RHPS4 affects ALT mechanisms through the induction of replicative stress that in turn is converted in DNA damage at telomeres, fueling recombination. In conclusion, our work indicates that RHPS4-induced telomeric DNA damage promotes overactivation of telomeric recombination in ALT cells, opening new questions on the therapeutic employment of G4 ligands in the treatment of ALT positive tumors.
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Affiliation(s)
- Roberta Amato
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
| | - Martina Valenzuela
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
| | - Francesco Berardinelli
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
- Correspondence: ; Tel.: +39-0657-33-6330
| | - Erica Salvati
- BPM-CNR Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy;
- Oncogenomic and Epigenetic Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy;
| | - Carmen Maresca
- Oncogenomic and Epigenetic Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy;
| | - Stefano Leone
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
| | - Antonio Antoccia
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
| | - Antonella Sgura
- Department of Science, Roma Tre University, I-00146 Rome, Italy; (R.A.); (M.V.); (S.L.); (A.A.); (A.S.)
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18
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Shioda N, Yabuki Y, Asamitsu S. [The potential of G-quadruplexes as a therapeutic target for neurological diseases]. Nihon Yakurigaku Zasshi 2019; 154:294-300. [PMID: 31787679 DOI: 10.1254/fpj.154.294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The most common form of DNA is a right-handed helix, the B-form DNA. DNA can also adopt a variety of alternative conformations, termed non-B-form DNA secondary structures, including the G-quadruplex (G4). Furthermore, non-canonical RNA G4 secondary structures are also observed. Recent bioinformatics analysis revealed genomic positions of G4. In addition, G4 formation may be associated with various biological functions, including DNA replication, transcription, epigenetic modification, and RNA metabolism. In this review, we focus on G4 structures in neuronal functions, which may have important roles reveal mechanisms underlying neurological disorders. In addition, we discuss the potential of G4s as a therapeutic target for neurological diseases.
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Affiliation(s)
- Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University
| | - Yasushi Yabuki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University
| | - Sefan Asamitsu
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University
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19
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Perspectives for Applying G-Quadruplex Structures in Neurobiology and Neuropharmacology. Int J Mol Sci 2019; 20:ijms20122884. [PMID: 31200506 PMCID: PMC6627371 DOI: 10.3390/ijms20122884] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/22/2022] Open
Abstract
The most common form of DNA is a right-handed helix or the B-form DNA. DNA can also adopt a variety of alternative conformations, non-B-form DNA secondary structures, including the DNA G-quadruplex (DNA-G4). Furthermore, besides stem-loops that yield A-form double-stranded RNA, non-canonical RNA G-quadruplex (RNA-G4) secondary structures are also observed. Recent bioinformatics analysis of the whole-genome and transcriptome obtained using G-quadruplex–specific antibodies and ligands, revealed genomic positions of G-quadruplexes. In addition, accumulating evidence pointed to the existence of these structures under physiologically- and pathologically-relevant conditions, with functional roles in vivo. In this review, we focused on DNA-G4 and RNA-G4, which may have important roles in neuronal function, and reveal mechanisms underlying neurological disorders related to synaptic dysfunction. In addition, we mention the potential of G-quadruplexes as therapeutic targets for neurological diseases.
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20
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Parivesh A, Barseghyan H, Délot E, Vilain E. Translating genomics to the clinical diagnosis of disorders/differences of sex development. Curr Top Dev Biol 2019; 134:317-375. [PMID: 30999980 PMCID: PMC7382024 DOI: 10.1016/bs.ctdb.2019.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The medical and psychosocial challenges faced by patients living with Disorders/Differences of Sex Development (DSD) and their families can be alleviated by a rapid and accurate diagnostic process. Clinical diagnosis of DSD is limited by a lack of standardization of anatomical and endocrine phenotyping and genetic testing, as well as poor genotype/phenotype correlation. Historically, DSD genes have been identified through positional cloning of disease-associated variants segregating in families and validation of candidates in animal and in vitro modeling of variant pathogenicity. Owing to the complexity of conditions grouped under DSD, genome-wide scanning methods are better suited for identifying disease causing gene variant(s) and providing a clinical diagnosis. Here, we review a number of established genomic tools (karyotyping, chromosomal microarrays and exome sequencing) used in clinic for DSD diagnosis, as well as emerging genomic technologies such as whole-genome (short-read) sequencing, long-read sequencing, and optical mapping used for novel DSD gene discovery. These, together with gene expression and epigenetic studies can potentiate the clinical diagnosis of DSD diagnostic rates and enhance the outcomes for patients and families.
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Affiliation(s)
- Abhinav Parivesh
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States
| | - Hayk Barseghyan
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States
| | - Emmanuèle Délot
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States.
| | - Eric Vilain
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States.
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21
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Yamaguchi K, Shioda N, Yabuki Y, Zhang C, Han F, Fukunaga K. SA4503, A Potent Sigma-1 Receptor Ligand, Ameliorates Synaptic Abnormalities and Cognitive Dysfunction in a Mouse Model of ATR-X Syndrome. Int J Mol Sci 2018; 19:E2811. [PMID: 30231518 PMCID: PMC6163584 DOI: 10.3390/ijms19092811] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 11/16/2022] Open
Abstract
α-thalassemia X-linked intellectual disability (ATR-X) syndrome is caused by mutations in ATRX. An ATR-X model mouse lacking Atrx exon 2 displays phenotypes that resemble symptoms in the human intellectual disability: cognitive defects and abnormal dendritic spine formation. We herein target activation of sigma-1 receptor (Sig-1R) that can induce potent neuroprotective and neuroregenerative effects by promoting the activity of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF). We demonstrated that treatment with SA4503, a potent activator of Sig-1R, reverses axonal development and dendritic spine abnormalities in cultured cortical neurons from ATR-X model mice. Moreover, the SA4503 treatment rescued cognitive deficits exhibited by the ATR-X model mice. We further found that significant decreases in the BDNF-protein level in the medial prefrontal cortex of ATR-X model mice were recovered with treatment of SA4503. These results indicate that the rescue of dendritic spine abnormalities through the activation of Sig-1R has a potential for post-diagnostic therapy in ATR-X syndrome.
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Affiliation(s)
- Kouya Yamaguchi
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
| | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.
| | - Yasushi Yabuki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
| | - Chen Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 31005, Zhejiang, China.
| | - Feng Han
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, Jiangsu, China.
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
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22
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Targeting G-quadruplex DNA as cognitive function therapy for ATR-X syndrome. Nat Med 2018; 24:802-813. [DOI: 10.1038/s41591-018-0018-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 02/12/2018] [Indexed: 01/08/2023]
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23
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Long Y, Wang X, Youmans DT, Cech TR. How do lncRNAs regulate transcription? SCIENCE ADVANCES 2017; 3:eaao2110. [PMID: 28959731 PMCID: PMC5617379 DOI: 10.1126/sciadv.aao2110] [Citation(s) in RCA: 466] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/12/2017] [Indexed: 05/11/2023]
Abstract
It has recently become apparent that RNA, itself the product of transcription, is a major regulator of the transcriptional process. In particular, long noncoding RNAs (lncRNAs), which are so numerous in eukaryotes, function in many cases as transcriptional regulators. These RNAs function through binding to histone-modifying complexes, to DNA binding proteins (including transcription factors), and even to RNA polymerase II. In other cases, it is the act of lncRNA transcription rather than the lncRNA product that appears to be regulatory. We review recent progress in elucidating the molecular mechanisms by which lncRNAs modulate gene expression and future opportunities in this research field.
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Affiliation(s)
- Yicheng Long
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Xueyin Wang
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Daniel T. Youmans
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
- Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, USA
| | - Thomas R. Cech
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
- Corresponding author.
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24
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Kovatcheva M, Liao W, Klein ME, Robine N, Geiger H, Crago AM, Dickson MA, Tap WD, Singer S, Koff A. ATRX is a regulator of therapy induced senescence in human cells. Nat Commun 2017; 8:386. [PMID: 28855512 PMCID: PMC5577318 DOI: 10.1038/s41467-017-00540-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/07/2017] [Indexed: 01/24/2023] Open
Abstract
Senescence is a state of stable cell cycle exit with important implications for development and disease. Here, we demonstrate that the chromatin remodeling enzyme ATRX is required for therapy-induced senescence. ATRX accumulates in nuclear foci and is required for therapy-induced senescence in multiple types of transformed cells exposed to either DNA damaging agents or CDK4 inhibitors. Mobilization into foci depends on the ability of ATRX to interact with H3K9me3 histone and HP1. Foci form soon after cells exit the cell cycle, before other hallmarks of senescence appear. Eliminating ATRX in senescent cells destabilizes the senescence-associated heterochromatic foci. Additionally, ATRX binds to and suppresses expression from the HRAS locus; repression of HRAS is sufficient to promote the transition of quiescent cells into senescence and preventing repression blocks progression into senescence. Thus ATRX is a critical regulator of therapy-induced senescence and acts in multiple ways to drive cells into this state. Therapy induced senescence (TIS) is a growth suppressive program activated by cytostatic agents in some cancer cells. Here the authors show that the chromatin remodeling enzyme ATRX is a regulator of TIS and drives cells into this state via multiple mechanisms.
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Affiliation(s)
- Marta Kovatcheva
- The Louis V. Gerstner Graduate School of Biomedical Sciences, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, 10065, USA.,Program in Molecular Biology, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | - Will Liao
- The New York Genome Center, New York, 10013, USA
| | - Mary E Klein
- The Louis V. Gerstner Graduate School of Biomedical Sciences, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, 10065, USA.,Program in Molecular Biology, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | | | | | - Aimee M Crago
- Program in Molecular Biology, Memorial Sloan Kettering Cancer Center, New York, 10065, USA.,Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | - Mark A Dickson
- Department of Medicine, Weill College of Medicine, Cornell University, New York, 10065, USA.,Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | - William D Tap
- Department of Medicine, Weill College of Medicine, Cornell University, New York, 10065, USA.,Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | - Samuel Singer
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, 10065, USA
| | - Andrew Koff
- The Louis V. Gerstner Graduate School of Biomedical Sciences, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, 10065, USA. .,Program in Molecular Biology, Memorial Sloan Kettering Cancer Center, New York, 10065, USA.
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25
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Dyer MA, Qadeer ZA, Valle-Garcia D, Bernstein E. ATRX and DAXX: Mechanisms and Mutations. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a026567. [PMID: 28062559 DOI: 10.1101/cshperspect.a026567] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent genome sequencing efforts in a variety of cancers have revealed mutations and/or structural alterations in ATRX and DAXX, which together encode a complex that deposits histone variant H3.3 into repetitive heterochromatin. These regions include retrotransposons, pericentric heterochromatin, and telomeres, the latter of which show deregulation in ATRX/DAXX-mutant tumors. Interestingly, ATRX and DAXX mutations are often found in pediatric tumors, suggesting a particular developmental context in which these mutations drive disease. Here we review the functions of ATRX and DAXX in chromatin regulation as well as their potential contributions to tumorigenesis. We place emphasis on the chromatin remodeler ATRX, which is mutated in the developmental disorder for which it is named, α-thalassemia, mental retardation, X-linked syndrome, and at high frequency in a number of adult and pediatric tumors.
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Affiliation(s)
- Michael A Dyer
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Zulekha A Qadeer
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - David Valle-Garcia
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Emily Bernstein
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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26
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Deeg KI, Chung I, Bauer C, Rippe K. Cancer Cells with Alternative Lengthening of Telomeres Do Not Display a General Hypersensitivity to ATR Inhibition. Front Oncol 2016; 6:186. [PMID: 27602331 PMCID: PMC4993795 DOI: 10.3389/fonc.2016.00186] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/05/2016] [Indexed: 01/20/2023] Open
Abstract
Telomere maintenance is a hallmark of cancer as it provides cancer cells with cellular immortality. A significant fraction of tumors uses the alternative lengthening of telomeres (ALT) pathway to elongate their telomeres and to gain an unlimited proliferation potential. Since the ALT pathway is unique to cancer cells, it represents a potentially valuable, currently unexploited target for anti-cancer therapies. Recently, it was proposed that ALT renders cells hypersensitive to ataxia telangiectasia- and RAD3-related (ATR) protein inhibitors (Flynn et al., Science 347, 273). Here, we measured the response of various ALT- or telomerase-positive cell lines to the ATR inhibitor VE-821. In addition, we compared the effect of the inhibitor on cell viability in isogenic cell lines, in which ALT was active or suppressed. In these experiments, a general ATR inhibitor sensitivity of cells with ALT could not be confirmed. We rather propose that the observed variations in sensitivity reflect differences between cell lines that are unrelated to ALT.
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Affiliation(s)
- Katharina I Deeg
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Inn Chung
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Caroline Bauer
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
| | - Karsten Rippe
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant Center , Heidelberg , Germany
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27
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Hamzeh AR, Nair P, Mohamed M, Saif F, Tawfiq N, Al-Ali MT, Bastaki F. A novel missense mutation in ATRX uncovered in a Yemeni family leads to alpha-thalassemia/mental retardation syndrome without alpha-thalassemia. Ir J Med Sci 2016; 186:333-337. [PMID: 26860117 DOI: 10.1007/s11845-016-1418-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/31/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Intellectual disability (ID) features in numerous heritable medical conditions that result from ATRX mutations. Alpha-thalassemia mental retardation syndrome (ATR-X syndrome) is the most notable manifestation of ATRX dysfunction. In addition to ID, genitourinary and craniofacial abnormalities are regularly observed with or without alpha-thalassemia. AIMS The study sought to characterize two cases of ATR-X in a Yemeni family clinically and molecularly. METHODS PCR amplification and Sanger sequencing were used to study the ATRX gene in a Yemeni family. Also, methylation-sensitive PCR was used to perform X-inactivation studies. CADD, SNAP2 and PolyPhen-2 helped to predict the functional consequences of the variant. RESULTS Molecular testing revealed a novel hemizygous missense mutation (c.5666T>G) in the ATRX gene in the two Yemeni brothers. This mutation was found in a heterozygous state in the mother, with the chromosome harboring the mutated allele being under strongly skewed X-inactivation. CONCLUSIONS The mutated gene is predicted to have a disrupted SNF-2 domain at a conserved residue; p.Leu1889Trp, which is deemed functionally damaging. This report offers, for the first time, full clinical and molecular characterization of a novel ATRX variant in an Arab family.
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Affiliation(s)
- A R Hamzeh
- Centre for Arab Genomic Studies, P.O. Box 22252, Dubai, United Arab Emirates.
| | - P Nair
- Centre for Arab Genomic Studies, P.O. Box 22252, Dubai, United Arab Emirates
| | - M Mohamed
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, United Arab Emirates
| | - F Saif
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, United Arab Emirates
| | - N Tawfiq
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, United Arab Emirates
| | - M T Al-Ali
- Centre for Arab Genomic Studies, P.O. Box 22252, Dubai, United Arab Emirates
| | - F Bastaki
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, United Arab Emirates
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28
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Abstract
ATRX was identified over 20 years ago as the gene responsible for a rare developmental disorder characterized by α-thalassemia and intellectual disability. Similarities to the sucrose nonfermentable SNF2 type chromatin remodelers initially suggested a role in transcriptional regulation. However, over the last years, our knowledge of the epigenetic activities of ATRX has expanded steadily. Recent exciting discoveries have propelled ATRX into the limelight of chromatin and telomere biology, development and cancer research. This review summarizes recent breakthroughs in understanding ATRX function in heterochromatin structure, genome stability and its frequent dysregulation in a variety of cancers.
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Affiliation(s)
- L Ashley Watson
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
| | - Hannah Goldberg
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
| | - Nathalie G Bérubé
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
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29
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Sarma K, Cifuentes-Rojas C, Ergun A, Del Rosario A, Jeon Y, White F, Sadreyev R, Lee JT. ATRX directs binding of PRC2 to Xist RNA and Polycomb targets. Cell 2015; 159:869-83. [PMID: 25417162 DOI: 10.1016/j.cell.2014.10.019] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/22/2014] [Accepted: 10/08/2014] [Indexed: 12/20/2022]
Abstract
X chromosome inactivation (XCI) depends on the long noncoding RNA Xist and its recruitment of Polycomb Repressive Complex 2 (PRC2). PRC2 is also targeted to other sites throughout the genome to effect transcriptional repression. Using XCI as a model, we apply an unbiased proteomics approach to isolate Xist and PRC2 regulators and identified ATRX. ATRX unexpectedly functions as a high-affinity RNA-binding protein that directly interacts with RepA/Xist RNA to promote loading of PRC2 in vivo. Without ATRX, PRC2 cannot load onto Xist RNA nor spread in cis along the X chromosome. Moreover, epigenomic profiling reveals that genome-wide targeting of PRC2 depends on ATRX, as loss of ATRX leads to spatial redistribution of PRC2 and derepression of Polycomb responsive genes. Thus, ATRX is a required specificity determinant for PRC2 targeting and function.
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Affiliation(s)
- Kavitha Sarma
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Catherine Cifuentes-Rojas
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Ayla Ergun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Amanda Del Rosario
- Department of Bioengineering, Massachusetts Institute of Technology, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Yesu Jeon
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Forest White
- Department of Bioengineering, Massachusetts Institute of Technology, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA USA
| | - Jeannie T Lee
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA; Department of Genetics, Harvard Medical School, Boston, MA USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA USA.
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30
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López-Falcón B, Meyer-Nava S, Hernández-Rodríguez B, Campos A, Montero D, Rudiño E, Vázquez M, Zurita M, Valadez-Graham V. Characterization of the Drosophila group ortholog to the amino-terminus of the alpha-thalassemia and mental retardation X-Linked (ATRX) vertebrate protein. PLoS One 2014; 9:e113182. [PMID: 25437195 PMCID: PMC4249797 DOI: 10.1371/journal.pone.0113182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/21/2014] [Indexed: 12/11/2022] Open
Abstract
The human ATRX gene encodes hATRX, a chromatin-remodeling protein harboring an helicase/ATPase and ADD domains. The ADD domain has two zinc fingers that bind to histone tails and mediate hATRX binding to chromatin. dAtrx, the putative ATRX homolog in Drosophila melanogaster, has a conserved helicase/ATPase domain but lacks the ADD domain. A bioinformatic search of the Drosophila genome using the human ADD sequence allowed us to identify the CG8290 annotated gene, which encodes three ADD harboring- isoforms generated by alternative splicing. This Drosophila ADD domain is highly similar in structure and in the amino acids which mediate the histone tail contacts to the ADD domain of hATRX as shown by 3D modeling. Very recently the CG8290 annotated gene has been named dadd1. We show through pull-down and CoIP assays that the products of the dadd1 gene interact physically with dAtrxL and HP1a and all of them mainly co-localize in the chromocenter, although euchromatic localization can also be observed through the chromosome arms. We confirm through ChIP analyses that these proteins are present in vivo in the same heterochromatic regions. The three isoforms are expressed throughout development. Flies carrying transheterozygous combinations of the dadd1 and atrx alleles are semi-viable and have different phenotypes including the appearance of melanotic masses. Interestingly, the dAdd1-b and c isoforms have extra domains, such as MADF, which suggest newly acquired functions of these proteins. These results strongly support that, in Drosophila, the atrx gene diverged and that the dadd1-encoded proteins participate with dAtrx in some cellular functions such as heterochromatin maintenance.
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Affiliation(s)
- Brenda López-Falcón
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Silvia Meyer-Nava
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Benjamín Hernández-Rodríguez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Adam Campos
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Daniel Montero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Enrique Rudiño
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Martha Vázquez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Mario Zurita
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail: (VVG); (MZ)
| | - Viviana Valadez-Graham
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail: (VVG); (MZ)
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31
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Ritchie K, Watson LA, Davidson B, Jiang Y, Bérubé NG. ATRX is required for maintenance of the neuroprogenitor cell pool in the embryonic mouse brain. Biol Open 2014; 3:1158-63. [PMID: 25395668 PMCID: PMC4265753 DOI: 10.1242/bio.20148730] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mutations in the alpha-thalassemia mental retardation X-linked (ATRX) gene cause a spectrum of abnormalities including intellectual disability, developmental delay, seizures, and microcephaly. The ATRX protein is highly enriched at heterochromatic repetitive sequences adjacent to the centromere, and ATRX depletion results in chromosome congression, segregation, and cohesion defects. Here, we show that Cre-mediated inactivation of Atrx in the embryonic mouse (Mus musculus) brain results in expansion of cerebral cortical layer VI, and a concurrent thinning of layers II–IV. We observed increased cell cycle exit during early-mid neurogenesis, and a depletion of apical progenitors by late neurogenesis in the Atrx-null neocortex, explaining the disproportionate layering. Premature differentiation was associated with an increased generation of outer radial glia (oRG) and TBR2-expressing basal progenitors, as well as increased generation of early-born post-mitotic projection neurons. Atrx deletion also reduced the fidelity of mitotic spindle orientation in apical progenitors, where mutant cells were often oriented at non-parallel angles of division relative to the ventricular surface. We conclude that ATRX is required for correct lamination of the mouse neocortex by regulating the timing of neuroprogenitor cell differentiation.
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Affiliation(s)
- Kieran Ritchie
- Departments of Paediatrics and Biochemistry, Children's Health Research Institute, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, ON N6C 2V5, Canada
| | - L Ashley Watson
- Departments of Paediatrics and Biochemistry, Children's Health Research Institute, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, ON N6C 2V5, Canada
| | - Benjamin Davidson
- Departments of Paediatrics and Biochemistry, Children's Health Research Institute, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, ON N6C 2V5, Canada
| | - Yan Jiang
- Departments of Paediatrics and Biochemistry, Children's Health Research Institute, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, ON N6C 2V5, Canada
| | - Nathalie G Bérubé
- Departments of Paediatrics and Biochemistry, Children's Health Research Institute, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, ON N6C 2V5, Canada
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32
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Kernohan KD, Vernimmen D, Gloor GB, Bérubé NG. Analysis of neonatal brain lacking ATRX or MeCP2 reveals changes in nucleosome density, CTCF binding and chromatin looping. Nucleic Acids Res 2014; 42:8356-68. [PMID: 24990380 PMCID: PMC4117782 DOI: 10.1093/nar/gku564] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
ATRX and MeCP2 belong to an expanding group of chromatin-associated proteins implicated in human neurodevelopmental disorders, although their gene-regulatory activities are not fully resolved. Loss of ATRX prevents full repression of an imprinted gene network in the postnatal brain and in this study we address the mechanistic aspects of this regulation. We show that ATRX binds many imprinted domains individually but that transient co-localization between imprinted domains in the nuclei of neurons does not require ATRX. We demonstrate that MeCP2 is required for ATRX recruitment and that deficiency of either ATRX or MeCP2 causes decreased frequency of long-range chromatin interactions associated with altered nucleosome density at CTCF-binding sites and reduced CTCF occupancy. These findings indicate that MeCP2 and ATRX regulate gene expression at a subset of imprinted domains by maintaining a nucleosome configuration conducive to CTCF binding and to the maintenance of higher order chromatin structure.
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Affiliation(s)
- Kristin D Kernohan
- Department of Biochemistry, University of Western Ontario, London N6C 2V5, Canada Children's Health Research Institute, London, Canada
| | - Douglas Vernimmen
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Gregory B Gloor
- Department of Biochemistry, University of Western Ontario, London N6C 2V5, Canada
| | - Nathalie G Bérubé
- Department of Biochemistry, University of Western Ontario, London N6C 2V5, Canada Children's Health Research Institute, London, Canada Department of Paediatrics, University of Western Ontario, London N6C 2V5, Canada
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33
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Clynes D, Jelinska C, Xella B, Ayyub H, Taylor S, Mitson M, Bachrati CZ, Higgs DR, Gibbons RJ. ATRX dysfunction induces replication defects in primary mouse cells. PLoS One 2014; 9:e92915. [PMID: 24651726 PMCID: PMC3961441 DOI: 10.1371/journal.pone.0092915] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/27/2014] [Indexed: 01/09/2023] Open
Abstract
The chromatin remodeling protein ATRX, which targets tandem repetitive DNA, has been shown to be required for expression of the alpha globin genes, for proliferation of a variety of cellular progenitors, for chromosome congression and for the maintenance of telomeres. Mutations in ATRX have recently been identified in tumours which maintain their telomeres by a telomerase independent pathway involving homologous recombination thought to be triggered by DNA damage. It is as yet unknown whether there is a central underlying mechanism associated with ATRX dysfunction which can explain the numerous cellular phenomena observed. There is, however, growing evidence for its role in the replication of various repetitive DNA templates which are thought to have a propensity to form secondary structures. Using a mouse knockout model we demonstrate that ATRX plays a direct role in facilitating DNA replication. Ablation of ATRX alone, although leading to a DNA damage response at telomeres, is not sufficient to trigger the alternative lengthening of telomere pathway in mouse embryonic stem cells.
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Affiliation(s)
- David Clynes
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Clare Jelinska
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Barbara Xella
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Helena Ayyub
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stephen Taylor
- Computational Biology Research Group, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Matthew Mitson
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Csanád Z Bachrati
- School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, United Kingdom
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Richard J Gibbons
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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Chandrasekaran P, Doss CGP, Nisha J, Sethumadhavan R, Shanthi V, Ramanathan K, Rajasekaran R. In silico analysis of detrimental mutations in ADD domain of chromatin remodeling protein ATRX that cause ATR-X syndrome: X-linked disorder. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13721-013-0031-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gibbons RJ. α-Thalassemia, mental retardation, and myelodysplastic syndrome. Cold Spring Harb Perspect Med 2012; 2:2/10/a011759. [PMID: 23028133 DOI: 10.1101/cshperspect.a011759] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This article describes three rare syndromes in which the presence of α-thalassemia provided an important clue to the molecular basis of the underlying condition. It exemplifies how rare diseases allied with careful clinical observation can lead to important biological principles. Two of the syndromes, ATR-16 and ATR-X, are characterized by α-thalassemia in association with multiple developmental abnormalities including mental retardation. The third condition, ATMDS, is an acquired disorder in which α-thalassemia arises in the context of myelodysplasia. Intriguingly, mutations in the chromatin remodeling factor, ATRX, are common to both ATR-X syndrome and ATMDS.
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Affiliation(s)
- Richard J Gibbons
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
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Newhart A, Rafalska-Metcalf IU, Yang T, Negorev DG, Janicki SM. Single-cell analysis of Daxx and ATRX-dependent transcriptional repression. J Cell Sci 2012; 125:5489-501. [PMID: 22976303 DOI: 10.1242/jcs.110148] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Histone H3.3 is a constitutively expressed H3 variant implicated in the epigenetic inheritance of chromatin structures. Recently, the PML-nuclear body (PML-NB)/Nuclear Domain 10 (ND10) proteins, Daxx and ATRX, were found to regulate replication-independent histone H3.3 chromatin assembly at telomeres and pericentric heterochromatin. As it is not completely understood how PML-NBs/ND10s regulate transcription and resistance to viral infection, we have used a CMV-promoter-regulated inducible transgene array, at which Daxx and ATRX are enriched, to delineate the mechanisms through which they regulate transcription. When integrated into HeLa cells, which express both Daxx and ATRX, the array is refractory to activation. However, transcription can be induced when ICP0, the HSV-1 E3 ubiquitin ligase required to reverse latency, is expressed. As ATRX and Daxx are depleted from the activated array in ICP0-expressing HeLa cells, this suggests that they are required to maintain a repressed chromatin environment. As histone H3.3 is strongly recruited to the ICP0-activated array but does not co-localize with the DNA, this also suggests that chromatin assembly is blocked during activation. The conclusion that the Daxx and ATRX pathway is required for transcriptional repression and chromatin assembly at this site is further supported by the finding that an array integrated into the ATRX-negative U2OS cell line can be robustly activated and that histone H3.3 is similarly recruited and unincorporated into the chromatin. Therefore, this study has important implications for understanding gene silencing, viral latency and PML-NB/ND10 function.
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Affiliation(s)
- Alyshia Newhart
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA
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37
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Ratnakumar K, Duarte LF, LeRoy G, Hasson D, Smeets D, Vardabasso C, Bönisch C, Zeng T, Xiang B, Zhang DY, Li H, Wang X, Hake SB, Schermelleh L, Garcia BA, Bernstein E. ATRX-mediated chromatin association of histone variant macroH2A1 regulates α-globin expression. Genes Dev 2012; 26:433-8. [PMID: 22391447 DOI: 10.1101/gad.179416.111] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The histone variant macroH2A generally associates with transcriptionally inert chromatin; however, the factors that regulate its chromatin incorporation remain elusive. Here, we identify the SWI/SNF helicase ATRX (α-thalassemia/MR, X-linked) as a novel macroH2A-interacting protein. Unlike its role in assisting H3.3 chromatin deposition, ATRX acts as a negative regulator of macroH2A's chromatin association. In human erythroleukemic cells deficient for ATRX, macroH2A accumulates at the HBA gene cluster on the subtelomere of chromosome 16, coinciding with the loss of α-globin expression. Collectively, our results implicate deregulation of macroH2A's distribution as a contributing factor to the α-thalassemia phenotype of ATRX syndrome.
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Affiliation(s)
- Kajan Ratnakumar
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA
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Abstract
Organisms require an appropriate balance of stability and reversibility in gene expression programmes to maintain cell identity or to enable responses to stimuli; epigenetic regulation is integral to this dynamic control. Post-translational modification of histones by methylation is an important and widespread type of chromatin modification that is known to influence biological processes in the context of development and cellular responses. To evaluate how histone methylation contributes to stable or reversible control, we provide a broad overview of how histone methylation is regulated and leads to biological outcomes. The importance of appropriately maintaining or reprogramming histone methylation is illustrated by its links to disease and ageing and possibly to transmission of traits across generations.
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Affiliation(s)
- Eric L Greer
- Cell Biology Department, Harvard Medical School and Division of Newborn Medicine, Children's Hospital Boston, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
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Sarkies P, Sale JE. Cellular epigenetic stability and cancer. Trends Genet 2012; 28:118-27. [PMID: 22226176 DOI: 10.1016/j.tig.2011.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 11/30/2011] [Accepted: 11/30/2011] [Indexed: 10/14/2022]
Abstract
When a cell divides, it must not only accurately duplicate its genome, but also restore its previous levels of gene expression. The information determining gene expression is often not directly encoded in the DNA and is hence termed 'epigenetic'. The molecular basis of epigenetic memory remains a subject of intense debate, but is likely to arise from the collaboration of several mechanisms, including histone post-translational modifications, transcription factors, DNA methylation and noncoding RNAs. In this article, we look at how these mechanisms interact to generate robust epigenetic states. We then consider recent observations that mitotic inheritance of stable gene expression can be compromised by interruption of DNA replication. We discuss how these data may provide direct evidence for a central role for histone modifications in transcriptional memory and how they could potentially provide an explanation for the some of the widespread alterations in transcription seen in cancer cells.
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Affiliation(s)
- Peter Sarkies
- Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Hills Road, Cambridge, CB2 0QH, UK
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De La Fuente R, Baumann C, Viveiros MM. Chromatin structure and ATRX function in mouse oocytes. Results Probl Cell Differ 2012; 55:45-68. [PMID: 22918800 DOI: 10.1007/978-3-642-30406-4_3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Differentiation of chromatin structure and function during oogenesis is essential to confer the mammalian oocyte with meiotic and developmental potential. Errors in chromosome segregation during female meiosis and subsequent transmission of an abnormal chromosome complement (aneuploidy) to the early conceptus are one of the leading causes of pregnancy loss in women. The chromatin remodeling protein ATRX (α-thalassemia mental retardation X-linked) has recently emerged as a critical factor involved in heterochromatin formation at mammalian centromeres during meiosis. In mammalian oocytes, ATRX binds to centromeric heterochromatin domains where it is required for accurate chromosome segregation. Loss of ATRX function induces abnormal meiotic chromosome morphology, reduces histone H3 phosphorylation, and promotes a high incidence of aneuploidy associated with severely reduced fertility. The presence of centromeric breaks during the transition to the first mitosis in the early embryo indicates that the role of ATRX in chromosome segregation is mediated through an epigenetic mechanism involving the maintenance of chromatin modifications associated with pericentric heterochromatin (PCH) formation and chromosome condensation. This is consistent with the existence of a potential molecular link between centromeric and PCH in the epigenetic control of centromere function and maintenance of chromosome stability in mammalian oocytes. Dissecting the molecular mechanisms of ATRX function during meiosis will have important clinical implications towards uncovering the epigenetic factors contributing to the onset of aneuploidy in the human oocyte.
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