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Banazadeh M, Abiri A, Poortaheri MM, Asnaashari L, Langarizadeh MA, Forootanfar H. Unexplored power of CRISPR-Cas9 in neuroscience, a multi-OMICs review. Int J Biol Macromol 2024; 263:130413. [PMID: 38408576 DOI: 10.1016/j.ijbiomac.2024.130413] [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] [Received: 02/03/2023] [Revised: 05/27/2023] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
The neuroscience and neurobiology of gene editing to enhance learning and memory is of paramount interest to the scientific community. The advancements of CRISPR system have created avenues to treat neurological disorders by means of versatile modalities varying from expression to suppression of genes and proteins. Neurodegenerative disorders have also been attributed to non-canonical DNA secondary structures by affecting neuron activity through controlling gene expression, nucleosome shape, transcription, translation, replication, and recombination. Changing DNA regulatory elements which could contribute to the fate and function of neurons are thoroughly discussed in this review. This study presents the ability of CRISPR system to boost learning power and memory, treat or cure genetically-based neurological disorders, and alleviate psychiatric diseases by altering the activity and the irritability of the neurons at the synaptic cleft through DNA manipulation, and also, epigenetic modifications using Cas9. We explore and examine how each different OMIC techniques can come useful when altering DNA sequences. Such insight into the underlying relationship between OMICs and cellular behaviors leads us to better neurological and psychiatric therapeutics by intelligently designing and utilizing the CRISPR/Cas9 technology.
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Affiliation(s)
- Mohammad Banazadeh
- Pharmaceutical Sciences and Cosmetic Products Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Ardavan Abiri
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA; Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520, USA
| | | | - Lida Asnaashari
- Student Research Committee, Kerman Universiy of Medical Sciences, Kerman, Iran
| | - Mohammad Amin Langarizadeh
- Department of Medicinal Chemistry, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran
| | - Hamid Forootanfar
- Pharmaceutical Sciences and Cosmetic Products Research Center, Kerman University of Medical Sciences, Kerman, Iran.
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2
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Schmidt A, Zhang H, Schmitt S, Rausch C, Popp O, Chen J, Cmarko D, Butter F, Dittmar G, Lermyte F, Cardoso MC. The Proteomic Composition and Organization of Constitutive Heterochromatin in Mouse Tissues. Cells 2024; 13:139. [PMID: 38247831 PMCID: PMC10814525 DOI: 10.3390/cells13020139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/13/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
Pericentric heterochromatin (PCH) forms spatio-temporarily distinct compartments and affects chromosome organization and stability. Albeit some of its components are known, an elucidation of its proteome and how it differs between tissues in vivo is lacking. Here, we find that PCH compartments are dynamically organized in a tissue-specific manner, possibly reflecting compositional differences. As the mouse brain and liver exhibit very different PCH architecture, we isolated native PCH fractions from these tissues, analyzed their protein compositions using quantitative mass spectrometry, and compared them to identify common and tissue-specific PCH proteins. In addition to heterochromatin-enriched proteins, the PCH proteome includes RNA/transcription and membrane-related proteins, which showed lower abundance than PCH-enriched proteins. Thus, we applied a cut-off of PCH-unspecific candidates based on their abundance and validated PCH-enriched proteins. Amongst the hits, MeCP2 was classified into brain PCH-enriched proteins, while linker histone H1 was not. We found that H1 and MeCP2 compete to bind to PCH and regulate PCH organization in opposite ways. Altogether, our workflow of unbiased PCH isolation, quantitative mass spectrometry, and validation-based analysis allowed the identification of proteins that are common and tissue-specifically enriched at PCH. Further investigation of selected hits revealed their opposing role in heterochromatin higher-order architecture in vivo.
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Affiliation(s)
- Annika Schmidt
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany (S.S.)
| | - Hui Zhang
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany (S.S.)
| | - Stephanie Schmitt
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany (S.S.)
| | - Cathia Rausch
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany (S.S.)
| | - Oliver Popp
- Proteomics Platform, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Jiaxuan Chen
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Dusan Cmarko
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00 Prague, Czech Republic
| | - Falk Butter
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Gunnar Dittmar
- Proteomics Platform, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Frederik Lermyte
- Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - M. Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany (S.S.)
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3
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Abstract
The eukaryotic nucleus displays a variety of membraneless compartments with distinct biomolecular composition and specific cellular activities. Emerging evidence indicates that protein-based liquid-liquid phase separation (LLPS) plays an essential role in the formation and dynamic regulation of heterochromatin compartmentalization. This feature is especially conspicuous at the pericentric heterochromatin domains. In this review, we will describe our understanding of heterochromatin organization and LLPS. In addition, we will highlight the increasing importance of multivalent weak homo- and heteromolecular interactions in LLPS-mediated heterochromatin compartmentalization in the complex environment inside living cells.
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Affiliation(s)
- Hui Zhang
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Weihua Qin
- Human Biology and Bioimaging, Faculty of Biology, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Hector Romero
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Human Biology and Bioimaging, Faculty of Biology, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - M. Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany,CONTACT M. Cristina Cardoso Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287Darmstadt, Germany
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4
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Melnikova L, Golovnin A. Multiple Roles of dXNP and dADD1- Drosophila Orthologs of ATRX Chromatin Remodeler. Int J Mol Sci 2023; 24:16486. [PMID: 38003676 PMCID: PMC10671109 DOI: 10.3390/ijms242216486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/11/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
The Drosophila melanogaster dADD1 and dXNP proteins are orthologues of the ADD and SNF2 domains of the vertebrate ATRX (Alpha-Thalassemia with mental Retardation X-related) protein. ATRX plays a role in general molecular processes, such as regulating chromatin status and gene expression, while dADD1 and dXNP have similar functions in the Drosophila genome. Both ATRX and dADD1/dXNP interact with various protein partners and participate in various regulatory complexes. Disruption of ATRX expression in humans leads to the development of α-thalassemia and cancer, especially glioma. However, the mechanisms that allow ATRX to regulate various cellular processes are poorly understood. Studying the functioning of dADD1/dXNP in the Drosophila model may contribute to understanding the mechanisms underlying the multifunctional action of ATRX and its connection with various cellular processes. This review provides a brief overview of the currently available information in mammals and Drosophila regarding the roles of ATRX, dXNP, and dADD1. It discusses possible mechanisms of action of complexes involving these proteins.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
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5
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Rowland ME, Jiang Y, Shafiq S, Ghahramani A, Pena-Ortiz MA, Dumeaux V, Bérubé NG. Systemic and intrinsic functions of ATRX in glial cell fate and CNS myelination in male mice. Nat Commun 2023; 14:7090. [PMID: 37925436 PMCID: PMC10625541 DOI: 10.1038/s41467-023-42752-y] [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] [Received: 01/17/2020] [Accepted: 10/20/2023] [Indexed: 11/06/2023] Open
Abstract
Myelin, an extension of the oligodendrocyte plasma membrane, wraps around axons to facilitate nerve conduction. Myelination is compromised in ATR-X intellectual disability syndrome patients, but the causes are unknown. We show that loss of ATRX leads to myelination deficits in male mice that are partially rectified upon systemic thyroxine administration. Targeted ATRX inactivation in either neurons or oligodendrocyte progenitor cells (OPCs) reveals OPC-intrinsic effects on myelination. OPCs lacking ATRX fail to differentiate along the oligodendrocyte lineage and acquire a more plastic state that favors astrocytic differentiation in vitro and in vivo. ATRX chromatin occupancy in OPCs greatly overlaps with that of the chromatin remodelers CHD7 and CHD8 as well as H3K27Ac, a mark of active enhancers. Overall, our data indicate that ATRX regulates the onset of myelination systemically via thyroxine, and by promoting OPC differentiation and suppressing astrogliogenesis. These functions of ATRX identified in mice could explain white matter pathogenesis observed in ATR-X syndrome patients.
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Affiliation(s)
- Megan E Rowland
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada
| | - Yan Jiang
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Sarfraz Shafiq
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Alireza Ghahramani
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Miguel A Pena-Ortiz
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada
- Graduate Program in Neuroscience, Western University, London, ON, Canada
| | - Vanessa Dumeaux
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Nathalie G Bérubé
- Children's Health Research Institute, Division of Genetics & Development, London, ON, Canada.
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
- Graduate Program in Neuroscience, Western University, London, ON, Canada.
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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6
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Kunert S, Linhard V, Weirich S, Choudalakis M, Osswald F, Krämer L, Köhler AR, Bröhm A, Wollenhaupt J, Schwalbe H, Jeltsch A. The MECP2-TRD domain interacts with the DNMT3A-ADD domain at the H3-tail binding site. Protein Sci 2023; 32:e4542. [PMID: 36519786 PMCID: PMC9798253 DOI: 10.1002/pro.4542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/01/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
The DNMT3A DNA methyltransferase and MECP2 methylation reader are highly expressed in neurons. Both proteins interact via their DNMT3A-ADD and MECP2-TRD domains, and the MECP2 interaction regulates the activity and subnuclear localization of DNMT3A. Here, we mapped the interface of both domains using peptide SPOT array binding, protein pull-down, equilibrium peptide binding assays, and structural analyses. The region D529-D531 on the surface of the ADD domain was identified as interaction point with the TRD domain. This includes important residues of the histone H3 N-terminal tail binding site to the ADD domain, explaining why TRD and H3 binding to the ADD domain is competitive. On the TRD domain, residues 214-228 containing K219 and K223 were found to be essential for the ADD interaction. This part represents a folded patch within the otherwise largely disordered TRD domain. A crystal structure analysis of ADD revealed that the identified H3/TDR lysine binding pocket is occupied by an arginine residue from a crystallographic neighbor in the ADD apoprotein structure. Finally, we show that mutations in the interface of ADD and TRD domains disrupt the cellular interaction of both proteins in NIH3T3 cells. In summary, our data show that the H3 peptide binding cleft of the ADD domain also mediates the interaction with the MECP2-TRD domain suggesting that this binding site may have a broader role also in the interaction of DNMT3A with other proteins leading to complex regulation options by competitive and PTM specific binding.
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Affiliation(s)
- Stefan Kunert
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Verena Linhard
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute for Organic Chemistry and Chemical BiologyGoethe UniversityFrankfurtGermany
| | - Sara Weirich
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Michel Choudalakis
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Florian Osswald
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Lisa Krämer
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Anja R. Köhler
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Alexander Bröhm
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
| | - Jan Wollenhaupt
- Macromolecular Crystallography GroupHelmholtz‐Zentrum BerlinBerlinGermany
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute for Organic Chemistry and Chemical BiologyGoethe UniversityFrankfurtGermany
| | - Albert Jeltsch
- Institute of Biochemistry and Technical BiochemistryUniversity of StuttgartStuttgartGermany
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7
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Shen J, Han Q, Li W, Chen X, Lu J, Zheng J, Xue S. miR-383-5p Regulated by the Transcription Factor CTCF Affects Neuronal Impairment in Cerebral Ischemia by Mediating Deacetylase HDAC9 Activity. Mol Neurobiol 2022; 59:6307-6320. [PMID: 35927544 DOI: 10.1007/s12035-022-02840-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/01/2022] [Indexed: 11/26/2022]
Abstract
Stroke, the leading cause of long-term disability worldwide, is caused by the blockage or hemorage of cerebral arteries. The resultant cerebral ischemia causes local neuronal death and brain injury. Histone deacetylase 9 (HDAC9) has been reported to be elevated in ischemic brain injury, but its mechanism in stroke is still enigmatic. The present study aimed to unveil the manner of regulation of HDAC9 expression and the effect of HDAC9 activation on neuronal function in cerebral ischemia. MicroRNAs (miRNAs) targeting HDAC9 were predicted utilizing bioinformatics analysis. We then constructed the oxygen glucose deprivation (OGD) cell model and the middle cerebral artery occlusion (MCAO) rat model, and elucidated the expression of CCCTC binding factor (CTCF)/miR-383-5p/HDAC9. Targeting between miR-383-5p and HDAC9 was verified by dual-luciferase reporter assay and RNAi. After conducting an overexpression/knockdown assay, we assessed neuronal impairment and brain injury. We found that CTCF inhibited miR-383-5p expression via its enrichment in the promoter region of miR-383-5p, whereas the miR-383-5p targeted and inhibited HDAC9 expression. In the OGD model and the MCAO model, we confirmed that elevation of HDAC9 regulated by the CTCF/miR-383-5p/HDAC9 pathway mediated apoptosis induced by endoplasmic reticulum stress, while reduction of HDAC9 alleviated apoptosis and the symptoms of cerebral infarction in MCAO rats. Thus, the CTCF/miR-383-5p/HDAC9 pathway may present a target for drug development against ischemic brain injury.
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Affiliation(s)
- Jun Shen
- Department of Neurology, The First Affiliated Hospital of Soochow University, No.188, Shizi Road, Suzhou, 215006, People's Republic of China
- Department of Neurology, The Affiliated Huai'an Hospital of Xuzhou Medical University & The Second People's Hospital of Huai'an, Huai'an, 223302, People's Republic of China
| | - Qiu Han
- Department of Neurology, Huai'an First People's Hospital & The Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, 223300, People's Republic of China
| | - Wangjun Li
- Department of Neurology, Changshu No. 2 People's Hospital (The 5th Clinical Medical College of Yangzhou University), Changshu, 215501, People's Republic of China
| | - Xiaochang Chen
- Department of Neurology, Hongze Huai'an District People's Hospital, No. 102, Huai'an, 223100, People's Republic of China.
| | - Jingmin Lu
- Department of Neurology, The Affiliated Huai'an Hospital of Xuzhou Medical University & The Second People's Hospital of Huai'an, Huai'an, 223302, People's Republic of China
| | - Jinyu Zheng
- Department of Neurosurgery, The Affiliated Huai'an Hospital of Xuzhou Medical University & The Second People's Hospital of Huai'an, Huai'an, 223302, People's Republic of China
| | - Shouru Xue
- Department of Neurology, The First Affiliated Hospital of Soochow University, No.188, Shizi Road, Suzhou, 215006, People's Republic of China.
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8
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The chromatin remodeller ATRX facilitates diverse nuclear processes, in a stochastic manner, in both heterochromatin and euchromatin. Nat Commun 2022; 13:3485. [PMID: 35710802 PMCID: PMC9203812 DOI: 10.1038/s41467-022-31194-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 06/07/2022] [Indexed: 12/20/2022] Open
Abstract
The chromatin remodeller ATRX interacts with the histone chaperone DAXX to deposit the histone variant H3.3 at sites of nucleosome turnover. ATRX is known to bind repetitive, heterochromatic regions of the genome including telomeres, ribosomal DNA and pericentric repeats, many of which are putative G-quadruplex forming sequences (PQS). At these sites ATRX plays an ancillary role in a wide range of nuclear processes facilitating replication, chromatin modification and transcription. Here, using an improved protocol for chromatin immunoprecipitation, we show that ATRX also binds active regulatory elements in euchromatin. Mutations in ATRX lead to perturbation of gene expression associated with a reduction in chromatin accessibility, histone modification, transcription factor binding and deposition of H3.3 at the sequences to which it normally binds. In erythroid cells where downregulation of α-globin expression is a hallmark of ATR-X syndrome, perturbation of chromatin accessibility and gene expression occurs in only a subset of cells. The stochastic nature of this process suggests that ATRX acts as a general facilitator of cell specific transcriptional and epigenetic programmes, both in heterochromatin and euchromatin.
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9
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Collins BE, Neul JL. Rett Syndrome and MECP2 Duplication Syndrome: Disorders of MeCP2 Dosage. Neuropsychiatr Dis Treat 2022; 18:2813-2835. [PMID: 36471747 PMCID: PMC9719276 DOI: 10.2147/ndt.s371483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused predominantly by loss-of-function mutations in the gene Methyl-CpG-binding protein 2 (MECP2), which encodes the MeCP2 protein. RTT is a MECP2-related disorder, along with MECP2 duplication syndrome (MDS), caused by gain-of-function duplications of MECP2. Nearly two decades of research have advanced our knowledge of MeCP2 function in health and disease. The following review will discuss MeCP2 protein function and its dysregulation in the MECP2-related disorders RTT and MDS. This will include a discussion of the genetic underpinnings of these disorders, specifically how sporadic X-chromosome mutations arise and manifest in specific populations. We will then review current diagnostic guidelines and clinical manifestations of RTT and MDS. Next, we will delve into MeCP2 biology, describing the dual landscapes of methylated DNA and its reader MeCP2 across the neuronal genome as well as the function of MeCP2 as a transcriptional modulator. Following this, we will outline common MECP2 mutations and genotype-phenotype correlations in both diseases, with particular focus on mutations associated with relatively mild disease in RTT. We will also summarize decades of disease modeling and resulting molecular, synaptic, and behavioral phenotypes associated with RTT and MDS. Finally, we list several therapeutics in the development pipeline for RTT and MDS and available evidence of their safety and efficacy.
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Affiliation(s)
- Bridget E Collins
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, Nashville, TN, USA
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10
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Babikir H, Wang L, Shamardani K, Catalan F, Sudhir S, Aghi MK, Raleigh DR, Phillips JJ, Diaz AA. ATRX regulates glial identity and the tumor microenvironment in IDH-mutant glioma. Genome Biol 2021; 22:311. [PMID: 34763709 PMCID: PMC8588616 DOI: 10.1186/s13059-021-02535-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/28/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Recent single-cell transcriptomic studies report that IDH-mutant gliomas share a common hierarchy of cellular phenotypes, independent of genetic subtype. However, the genetic differences between IDH-mutant glioma subtypes are prognostic, predictive of response to chemotherapy, and correlate with distinct tumor microenvironments. RESULTS To reconcile these findings, we profile 22 human IDH-mutant gliomas using scATAC-seq and scRNA-seq. We determine the cell-type-specific differences in transcription factor expression and associated regulatory grammars between IDH-mutant glioma subtypes. We find that while IDH-mutant gliomas do share a common distribution of cell types, there are significant differences in the expression and targeting of transcription factors that regulate glial identity and cytokine elaboration. We knock out the chromatin remodeler ATRX, which suffers loss-of-function alterations in most IDH-mutant astrocytomas, in an IDH-mutant immunocompetent intracranial murine model. We find that both human ATRX-mutant gliomas and murine ATRX-knockout gliomas are more heavily infiltrated by immunosuppressive monocytic-lineage cells derived from circulation than ATRX-intact gliomas, in an IDH-mutant background. ATRX knockout in murine glioma recapitulates gene expression and open chromatin signatures that are specific to human ATRX-mutant astrocytomas, including drivers of astrocytic lineage and immune-cell chemotaxis. Through single-cell cleavage under targets and tagmentation assays and meta-analysis of public data, we show that ATRX loss leads to a global depletion in CCCTC-binding factor association with DNA, gene dysregulation along associated chromatin loops, and protection from therapy-induced senescence. CONCLUSIONS These studies explain how IDH-mutant gliomas from different subtypes maintain distinct phenotypes and tumor microenvironments despite a common lineage hierarchy.
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Affiliation(s)
- Husam Babikir
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Lin Wang
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Karin Shamardani
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Francisca Catalan
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Sweta Sudhir
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Manish K Aghi
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - David R Raleigh
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Joanna J Phillips
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA
| | - Aaron A Diaz
- Department of Neurological Surgery, University of California, Aaron Diaz, 1450 3rd Street, San Francisco, CA, 94158, USA.
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11
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Exploring chromatin structural roles of non-coding RNAs at imprinted domains. Biochem Soc Trans 2021; 49:1867-1879. [PMID: 34338292 PMCID: PMC8421051 DOI: 10.1042/bst20210758] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 12/11/2022]
Abstract
Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.
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12
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Wong X, Cutler JA, Hoskins VE, Gordon M, Madugundu AK, Pandey A, Reddy KL. Mapping the micro-proteome of the nuclear lamina and lamina-associated domains. Life Sci Alliance 2021; 4:e202000774. [PMID: 33758005 PMCID: PMC8008952 DOI: 10.26508/lsa.202000774] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/13/2023] Open
Abstract
The nuclear lamina is a proteinaceous network of filaments that provide both structural and gene regulatory functions by tethering proteins and large domains of DNA, the so-called lamina-associated domains (LADs), to the periphery of the nucleus. LADs are a large fraction of the mammalian genome that are repressed, in part, by their association to the nuclear periphery. The genesis and maintenance of LADs is poorly understood as are the proteins that participate in these functions. In an effort to identify proteins that reside at the nuclear periphery and potentially interact with LADs, we have taken a two-pronged approach. First, we have undertaken an interactome analysis of the inner nuclear membrane bound LAP2β to further characterize the nuclear lamina proteome. To accomplish this, we have leveraged the BioID system, which previously has been successfully used to characterize the nuclear lamina proteome. Second, we have established a system to identify proteins that bind to LADs by developing a chromatin-directed BioID system. We combined the BioID system with the m6A-tracer system which binds to LADs in live cells to identify both LAD proximal and nuclear lamina proteins. In combining these datasets, we have further characterized the protein network at the nuclear lamina, identified putative LAD proximal proteins and found several proteins that appear to interface with both micro-proteomes. Importantly, several proteins essential for LAD function, including heterochromatin regulating proteins related to H3K9 methylation, were identified in this study.
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Affiliation(s)
- Xianrong Wong
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Laboratory of Developmental and Regenerative Biology, Institute of Medical Biology, Agency for Science, Technology and Research (A∗STAR), Immunos, Singapore
| | - Jevon A Cutler
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Victoria E Hoskins
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Molly Gordon
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anil K Madugundu
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
| | - Akhilesh Pandey
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
- Manipal Academy of Higher Education (MAHE), Manipal, India
- Departments of Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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13
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Sharifi O, Yasui DH. The Molecular Functions of MeCP2 in Rett Syndrome Pathology. Front Genet 2021; 12:624290. [PMID: 33968128 PMCID: PMC8102816 DOI: 10.3389/fgene.2021.624290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/08/2021] [Indexed: 12/13/2022] Open
Abstract
MeCP2 protein, encoded by the MECP2 gene, binds to DNA and affects transcription. Outside of this activity the true range of MeCP2 function is still not entirely clear. As MECP2 gene mutations cause the neurodevelopmental disorder Rett syndrome in 1 in 10,000 female births, much of what is known about the biologic function of MeCP2 comes from studying human cell culture models and rodent models with Mecp2 gene mutations. In this review, the full scope of MeCP2 research available in the NIH Pubmed (https://pubmed.ncbi.nlm.nih.gov/) data base to date is considered. While not all original research can be mentioned due to space limitations, the main aspects of MeCP2 and Rett syndrome research are discussed while highlighting the work of individual researchers and research groups. First, the primary functions of MeCP2 relevant to Rett syndrome are summarized and explored. Second, the conflicting evidence and controversies surrounding emerging aspects of MeCP2 biology are examined. Next, the most obvious gaps in MeCP2 research studies are noted. Finally, the most recent discoveries in MeCP2 and Rett syndrome research are explored with a focus on the potential and pitfalls of novel treatments and therapies.
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Affiliation(s)
- Osman Sharifi
- LaSalle Laboratory, Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, CA, United States
| | - Dag H Yasui
- LaSalle Laboratory, Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, CA, United States
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14
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D'Mello SR. MECP2 and the Biology of MECP2 Duplication Syndrome. J Neurochem 2021; 159:29-60. [PMID: 33638179 DOI: 10.1111/jnc.15331] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/21/2021] [Accepted: 02/18/2021] [Indexed: 11/27/2022]
Abstract
MECP2 duplication syndrome (MDS), a rare X-linked genomic disorder affecting predominantly males, is caused by duplication of the chromosomal region containing the methyl CpG binding protein-2 (MECP2) gene, which encodes methyl-CpG-binding protein 2 (MECP2), a multi-functional protein required for proper brain development and maintenance of brain function during adulthood. Disease symptoms include severe motor and cognitive impairment, delayed or absent speech development, autistic features, seizures, ataxia, recurrent respiratory infections and shortened lifespan. The cellular and molecular mechanisms by which a relatively modest increase in MECP2 protein causes such severe disease symptoms are poorly understood and consequently there are no treatments available for this fatal disorder. This review summarizes what is known to date about the structure and complex regulation of MECP2 and its many functions in the developing and adult brain. Additionally, recent experimental findings on the cellular and molecular underpinnings of MDS based on cell culture and mouse models of the disorder are reviewed. The emerging picture from these studies is that MDS is a neurodegenerative disorder in which neurons die in specific parts of the central nervous system, including the cortex, hippocampus, cerebellum and spinal cord. Neuronal death likely results from astrocytic dysfunction, including a breakdown of glutamate homeostatic mechanisms. The role of elevations in the expression of glial acidic fibrillary protein (GFAP) in astrocytes and the microtubule-associated protein, Tau, in neurons to the pathogenesis of MDS is discussed. Lastly, potential therapeutic strategies to potentially treat MDS are discussed.
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15
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Magaña-Acosta M, Valadez-Graham V. Chromatin Remodelers in the 3D Nuclear Compartment. Front Genet 2020; 11:600615. [PMID: 33329746 PMCID: PMC7673392 DOI: 10.3389/fgene.2020.600615] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022] Open
Abstract
Chromatin remodeling complexes (CRCs) use ATP hydrolysis to maintain correct expression profiles, chromatin stability, and inherited epigenetic states. More than 20 CRCs have been described to date, which encompass four large families defined by their ATPase subunits. These complexes and their subunits are conserved from yeast to humans through evolution. Their activities depend on their catalytic subunits which through ATP hydrolysis provide the energy necessary to fulfill cellular functions such as gene transcription, DNA repair, and transposon silencing. These activities take place at the first levels of chromatin compaction, and CRCs have been recognized as essential elements of chromatin dynamics. Recent studies have demonstrated an important role for these complexes in the maintenance of higher order chromatin structure. In this review, we present an overview of the organization of the genome within the cell nucleus, the different levels of chromatin compaction, and importance of the architectural proteins, and discuss the role of CRCs and how their functions contribute to the dynamics of the 3D genome organization.
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Affiliation(s)
- Mauro Magaña-Acosta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Viviana Valadez-Graham
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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16
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MeCP2 Levels Regulate the 3D Structure of Heterochromatic Foci in Mouse Neurons. J Neurosci 2020; 40:8746-8766. [PMID: 33046553 DOI: 10.1523/jneurosci.1281-19.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/25/2020] [Accepted: 09/17/2020] [Indexed: 02/02/2023] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a nuclear protein critical for normal brain function, and both depletion and overexpression of MeCP2 lead to severe neurodevelopmental disease, Rett syndrome (RTT) and MECP2 multiplication disorder, respectively. However, the molecular mechanism by which abnormal MeCP2 dosage causes neuronal dysfunction remains unclear. As MeCP2 expression is nearly equivalent to that of core histones and because it binds DNA throughout the genome, one possible function of MeCP2 is to regulate the 3D structure of chromatin. Here, to examine whether and how MeCP2 levels impact chromatin structure, we used high-resolution confocal and electron microscopy and examined heterochromatic foci of neurons in mice. Using models of RTT and MECP2 triplication syndrome, we found that the heterochromatin structure was significantly affected by the alteration in MeCP2 levels. Analysis of mice expressing either MeCP2-R270X or MeCP2-G273X, which have nonsense mutations in the upstream and downstream regions of the AT-hook 2 domain, respectively, showed that the magnitude of heterochromatin changes was tightly correlated with the phenotypic severity. Postnatal alteration in MeCP2 levels also induced significant changes in the heterochromatin structure, which underscored importance of correct MeCP2 dosage in mature neurons. Finally, functional analysis of MeCP2-overexpressing mice showed that the behavioral and transcriptomic alterations in these mice correlated significantly with the MeCP2 levels and occurred in parallel with the heterochromatin changes. Taken together, our findings demonstrate the essential role of MeCP2 in regulating the 3D structure of neuronal chromatin, which may serve as a potential mechanism that drives pathogenesis of MeCP2-related disorders.SIGNIFICANCE STATEMENT Neuronal function is critically dependent on methyl-CpG binding protein 2 (MeCP2), a nuclear protein abundantly expressed in neurons. The importance of MeCP2 is underscored by the severe childhood neurologic disorders, Rett syndrome (RTT) and MECP2 multiplication disorders, which are caused by depletion and overabundance of MeCP2, respectively. To clarify the molecular function of MeCP2 and to understand the pathogenesis of MECP2-related disorders, we performed detailed structural analyses of neuronal nuclei by using mouse models and high-resolution microscopy. We show that the level of MeCP2 critically regulates 3D structure of heterochromatic foci, and this is mediated in part by the AT-hook 2 domain of MeCP2. Our results demonstrate that one primary function of MeCP2 is to regulate chromatin structure.
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17
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MeCP2 and Chromatin Compartmentalization. Cells 2020; 9:cells9040878. [PMID: 32260176 PMCID: PMC7226738 DOI: 10.3390/cells9040878] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 12/24/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a multifunctional epigenetic reader playing a role in transcriptional regulation and chromatin structure, which was linked to Rett syndrome in humans. Here, we focus on its isoforms and functional domains, interactions, modifications and mutations found in Rett patients. Finally, we address how these properties regulate and mediate the ability of MeCP2 to orchestrate chromatin compartmentalization and higher order genome architecture.
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18
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Farhadova S, Gomez-Velazquez M, Feil R. Stability and Lability of Parental Methylation Imprints in Development and Disease. Genes (Basel) 2019; 10:genes10120999. [PMID: 31810366 PMCID: PMC6947649 DOI: 10.3390/genes10120999] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 02/06/2023] Open
Abstract
DNA methylation plays essential roles in mammals. Of particular interest are parental methylation marks that originate from the oocyte or the sperm, and bring about mono-allelic gene expression at defined chromosomal regions. The remarkable somatic stability of these parental imprints in the pre-implantation embryo—where they resist global waves of DNA demethylation—is not fully understood despite the importance of this phenomenon. After implantation, some methylation imprints persist in the placenta only, a tissue in which many genes are imprinted. Again here, the underlying epigenetic mechanisms are not clear. Mouse studies have pinpointed the involvement of transcription factors, covalent histone modifications, and histone variants. These and other features linked to the stability of methylation imprints are instructive as concerns their conservation in humans, in which different congenital disorders are caused by perturbed parental imprints. Here, we discuss DNA and histone methylation imprints, and why unravelling maintenance mechanisms is important for understanding imprinting disorders in humans.
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19
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Marano D, Fioriniello S, Fiorillo F, Gibbons RJ, D'Esposito M, Della Ragione F. ATRX Contributes to MeCP2-Mediated Pericentric Heterochromatin Organization during Neural Differentiation. Int J Mol Sci 2019; 20:E5371. [PMID: 31671722 PMCID: PMC6862095 DOI: 10.3390/ijms20215371] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a multi-function factor involved in locus-specific transcriptional modulation and the regulation of genome architecture, e.g., pericentric heterochromatin (PCH) organization. MECP2 mutations are responsible for Rett syndrome (RTT), a devastating postnatal neurodevelopmental disorder, the pathogenetic mechanisms of which are still unknown. MeCP2, together with Alpha-thalassemia/mental retardation syndrome X-linked protein (ATRX), accumulates at chromocenters, which are repressive PCH domains. As with MECP2, mutations in ATRX cause ATR-X syndrome which is associated with severe intellectual disability. We exploited two murine embryonic stem cell lines, in which the expression of MeCP2 or ATRX is abolished. Through immunostaining, chromatin immunoprecipitation and western blot, we show that MeCP2 and ATRX are reciprocally dependent both for their expression and targeting to chromocenters. Moreover, ATRX plays a role in the accumulation of members of the heterochromatin protein 1 (HP1) family at PCH and, as MeCP2, modulates their expression. Furthermore, ATRX and HP1 targeting to chromocenters depends on an RNA component. 3D-DNA fluorescence in situ hybridization (FISH) highlighted, for the first time, a contribution of ATRX in MeCP2-mediated chromocenter clustering during neural differentiation. Overall, we provide a detailed dissection of the functional interplay between MeCP2 and ATRX in higher-order PCH organization in neurons. Our findings suggest molecular defects common to RTT and ATR-X syndrome, including an alteration in PCH.
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Affiliation(s)
- Domenico Marano
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Salvatore Fioriniello
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Francesca Fiorillo
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Richard J Gibbons
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
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20
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Gulmez Karaca K, Brito DV, Oliveira AM. MeCP2: A Critical Regulator of Chromatin in Neurodevelopment and Adult Brain Function. Int J Mol Sci 2019; 20:ijms20184577. [PMID: 31527487 PMCID: PMC6769791 DOI: 10.3390/ijms20184577] [Citation(s) in RCA: 35] [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: 08/06/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 01/08/2023] Open
Abstract
Methyl CpG binding protein 2 (MeCP2) was first identified as a nuclear protein with a transcriptional repressor role that recognizes DNA methylation marks. MeCP2 has a well-established function in neurodevelopment, as evidenced by the severe neurological impairments characteristic of the Rett syndrome (RTT) pathology and the MeCP2 duplication syndrome (MDS), caused by loss or gain of MeCP2 function, respectively. Research aimed at the underlying pathophysiological mechanisms of RTT and MDS has significantly advanced our understanding of MeCP2 functions in the nervous system. It has revealed, however, that MeCP2 has more varied and complex roles than previously thought. Here we review recent insights into the functions of MeCP2 in neurodevelopment and the less explored requirement for MeCP2 in adult brain function. We focus on the emerging view that MeCP2 is a global chromatin organizer. Finally, we discuss how the individual functions of MeCP2 in neurodevelopment and adulthood are linked to its role as a chromatin regulator.
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Affiliation(s)
- Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 EN Nijmegen, The Netherlands
| | - David V.C. Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
| | - Ana M.M. Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Correspondence: ; Tel.: +49-(0)6221-5416510
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21
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Genomic insights into MeCP2 function: A role for the maintenance of chromatin architecture. Curr Opin Neurobiol 2019; 59:174-179. [PMID: 31430649 DOI: 10.1016/j.conb.2019.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/07/2019] [Indexed: 01/05/2023]
Abstract
Methyl-CpG binding protein 2 (MeCP2) plays fundamental roles in the nervous system, as both gain-of-function and loss-of-function of MECP2 are associated with severe neurological conditions. Understanding the molecular function of MeCP2 will not only provide insights into the pathogenesis of MeCP2-related disorders, but will also shed light on the epigenetic regulation of neuronal function. In the past few years, a number of studies have provided mechanistic evidence that MeCP2 recruits co-repressor complexes to particular sequences of methylated DNA. Additionally, innovative design and high-throughput sequencing technologies have provided opportunities to study the effects of MeCP2 on the neuronal transcriptome at an unprecedented level of detail, demonstrating that MeCP2 modulates gene expression in a context-specific manner. These findings have raised new questions and challenged current models of MeCP2 function. In this review, we describe several recent developments, highlight future challenges, and articulate a model by which MeCP2 functions as an organizer of chromatin architecture to modulate global gene expression in the nervous system.
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22
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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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23
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Ito K, Takizawa T. Nuclear Architecture in the Nervous System: Development, Function, and Neurodevelopmental Diseases. Front Genet 2018; 9:308. [PMID: 30127803 PMCID: PMC6087739 DOI: 10.3389/fgene.2018.00308] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 07/19/2018] [Indexed: 12/22/2022] Open
Abstract
Decades of study have shown that epigenetic regulation plays an important role in neural development and function. Several layers of epigenetic mechanisms control functions of the eukaryotic cell nucleus, a well-organized subcellular organelle with distinct compartments: chromatin, its related architectural proteins, and nuclear bodies. As these components function together in the epigenetic regulation of cellular development and functions, they are collectively termed nuclear architecture. In the nervous system, dynamic rearrangement of nuclear architecture correlates with alteration of transcription programs. During maturation and upon depolarization, neurons undergo a reorganization of nuclear architecture that alters gene expression programs. As such changes allow for specialized functions, including learning and memory, nuclear architecture is distinct among cell types. Studying nuclear architecture of neurons may uncover cell-division-independent mechanisms of global and local changes to nuclear architecture. We herein review recent research concerning nuclear architecture in the nervous system and will discuss its importance to the development, maturation, function, and diseases of the nervous system.
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Affiliation(s)
- Kenji Ito
- Department of Pediatrics, Graduate School of Medicine, Gunma University, Maebashi, Japan.,Division of Stem Cell Pathology, Center for Experimental Medicine and Systems Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Takumi Takizawa
- Department of Pediatrics, Graduate School of Medicine, Gunma University, Maebashi, Japan
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24
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Garcia-Moreno SA, Plebanek MP, Capel B. Epigenetic regulation of male fate commitment from an initially bipotential system. Mol Cell Endocrinol 2018; 468:19-30. [PMID: 29410272 PMCID: PMC6084468 DOI: 10.1016/j.mce.2018.01.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 12/21/2022]
Abstract
A fundamental goal in biology is to understand how distinct cell types containing the same genetic information arise from a single stem cell throughout development. Sex determination is a key developmental process that requires a unidirectional commitment of an initially bipotential gonad towards either the male or female fate. This makes sex determination a unique model to study cell fate commitment and differentiation in vivo. We have focused this review on the accumulating evidence that epigenetic mechanisms contribute to the bipotential state of the fetal gonad and to the regulation of chromatin accessibility during and immediately downstream of the primary sex-determining switch that establishes the male fate.
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Affiliation(s)
| | | | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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25
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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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26
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Davis L, Onn I, Elliott E. The emerging roles for the chromatin structure regulators CTCF and cohesin in neurodevelopment and behavior. Cell Mol Life Sci 2018; 75:1205-1214. [PMID: 29110030 PMCID: PMC11105208 DOI: 10.1007/s00018-017-2706-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/09/2017] [Accepted: 10/31/2017] [Indexed: 12/19/2022]
Abstract
Recent genetic and technological advances have determined a role for chromatin structure in neurodevelopment. In particular, compounding evidence has established roles for CTCF and cohesin, two elements that are central in the establishment of chromatin structure, in proper neurodevelopment and in regulation of behavior. Genetic aberrations in CTCF, and in subunits of the cohesin complex, have been associated with neurodevelopmental disorders in human genetic studies, and subsequent animal studies have established definitive, although sometime opposing roles, for these factors in neurodevelopment and behavior. Considering the centrality of these factors in cellular processes in general, the mechanisms through which dysregulation of CTCF and cohesin leads specifically to neurological phenotypes is intriguing, although poorly understood. The connection between CTCF, cohesin, chromatin structure, and behavior is likely to be one of the next frontiers in our understanding of the development of behavior in general, and neurodevelopmental disorders in particular.
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Affiliation(s)
- Liron Davis
- Molecular and Behavioral Neurosciences Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, Hanrietta Sold 8, 1311502, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, 1311502, Safed, Israel
| | - Evan Elliott
- Molecular and Behavioral Neurosciences Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, Hanrietta Sold 8, 1311502, Safed, Israel.
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27
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Arzate-Mejía RG, Recillas-Targa F, Corces VG. Developing in 3D: the role of CTCF in cell differentiation. Development 2018; 145:145/6/dev137729. [PMID: 29567640 DOI: 10.1242/dev.137729] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
CTCF is a highly conserved zinc-finger DNA-binding protein that mediates interactions between distant sequences in the genome. As a consequence, CTCF regulates enhancer-promoter interactions and contributes to the three-dimensional organization of the genome. Recent studies indicate that CTCF is developmentally regulated, suggesting that it plays a role in cell type-specific genome organization. Here, we review these studies and discuss how CTCF functions during the development of various cell and tissue types, ranging from embryonic stem cells and gametes, to neural, muscle and cardiac cells. We propose that the lineage-specific control of CTCF levels, and its partnership with lineage-specific transcription factors, allows for the control of cell type-specific gene expression via chromatin looping.
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Affiliation(s)
- Rodrigo G Arzate-Mejía
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad de México, México
| | - Félix Recillas-Targa
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad de México, México
| | - Victor G Corces
- Department of Biology, Emory University, Atlanta, GA 30322, USA
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Xu C, Corces VG. Nascent DNA methylome mapping reveals inheritance of hemimethylation at CTCF/cohesin sites. Science 2018; 359:1166-1170. [PMID: 29590048 PMCID: PMC6359960 DOI: 10.1126/science.aan5480] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 12/15/2017] [Accepted: 01/16/2018] [Indexed: 12/29/2022]
Abstract
The faithful inheritance of the epigenome is critical for cells to maintain gene expression programs and cellular identity across cell divisions. We mapped strand-specific DNA methylation after replication forks and show maintenance of the vast majority of the DNA methylome within 20 minutes of replication and inheritance of some hemimethylated CpG dinucleotides (hemiCpGs). Mapping the nascent DNA methylome targeted by each of the three DNA methyltransferases (DNMTs) reveals interactions between DNMTs and substrate daughter cytosines en route to maintenance methylation or hemimethylation. Finally, we show the inheritance of hemiCpGs at short regions flanking CCCTC-binding factor (CTCF)/cohesin binding sites in pluripotent cells. Elimination of hemimethylation causes reduced frequency of chromatin interactions emanating from these sites, suggesting a role for hemimethylation as a stable epigenetic mark regulating CTCF-mediated chromatin interactions.
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Affiliation(s)
- Chenhuan Xu
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Victor G Corces
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
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29
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Alrezk R, Suarez A, Tena I, Pacak K. Update of Pheochromocytoma Syndromes: Genetics, Biochemical Evaluation, and Imaging. Front Endocrinol (Lausanne) 2018; 9:515. [PMID: 30538672 PMCID: PMC6277481 DOI: 10.3389/fendo.2018.00515] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/16/2018] [Indexed: 12/12/2022] Open
Abstract
Pheochromocytomas and paragangliomas (PCCs/PGLs) are rare commonly benign neuroendocrine tumors that share pathology features and clinical behavior in many cases. While PCCs are chromaffin-derived tumors that arise within the adrenal medulla, PGLs are neural-crest-derived tumors that originate at the extraadrenal paraganglia. Pheochromocytoma-paraganglioma (PPGL) syndromes are rapidly evolving entities in endocrinology and oncology. Discoveries over the last decade have significantly improved our understanding of the disease. These include the finding of new hereditary forms of PPGL and their associated susceptibility genes. Additionally, the availability of new functional imaging tools and advances in targeted radionuclide therapy have improved diagnostic accuracy and provided us with new therapeutic options. In this review article, we present the most recent advances in this field and provide an update of the biochemical classification that further reflects our understanding of the disease.
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Affiliation(s)
- Rami Alrezk
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- Cleveland Clinic, Adrenal Center, Endocrinology and Metabolism Institute, Cleveland, OH, United States
| | - Andres Suarez
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Isabel Tena
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- Provincial Hospital, Castellon, Spain
| | - Karel Pacak
- Section on Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Karel Pacak
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30
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Epigenetic Etiology of Intellectual Disability. J Neurosci 2017; 37:10773-10782. [PMID: 29118205 DOI: 10.1523/jneurosci.1840-17.2017] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 12/31/2022] Open
Abstract
Intellectual disability (ID) is a prevailing neurodevelopmental condition associated with impaired cognitive and adaptive behaviors. Many chromatin-modifying enzymes and other epigenetic regulators have been genetically associated with ID disorders (IDDs). Here we review how alterations in the function of histone modifiers, chromatin remodelers, and methyl-DNA binding proteins contribute to neurodevelopmental defects and altered brain plasticity. We also discuss how progress in human genetics has led to the generation of mouse models that unveil the molecular etiology of ID, and outline the direction in which this field is moving to identify therapeutic strategies for IDDs. Importantly, because the chromatin regulators linked to IDDs often target common downstream genes and cellular processes, the impact of research in individual syndromes goes well beyond each syndrome and can also contribute to the understanding and therapy of other IDDs. Furthermore, the investigation of these disorders helps us to understand the role of chromatin regulators in brain development, plasticity, and gene expression, thereby answering fundamental questions in neurobiology.
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31
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Abstract
This paper provides a brief introductory review of the most recent advances in our knowledge about the structural and functional aspects of two transcriptional regulators: MeCP2, a protein whose mutated forms are involved in Rett syndrome; and CTCF, a constitutive transcriptional insulator. This is followed by a description of the PTMs affecting these two proteins and an analysis of their known interacting partners. A special emphasis is placed on the recent studies connecting these two proteins, focusing on the still poorly understood potential structural and functional interactions between the two of them on the chromatin substrate. An overview is provided for some of the currently known genes that are dually regulated by these two proteins. Finally, a model is put forward to account for their possible involvement in their regulation of gene expression.
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Affiliation(s)
- Juan Ausió
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada.,b Center for Biomedical Research, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Philippe T Georgel
- c Department of Biological Sciences, Marshall University, Huntington, WV 25755, USA.,d Cell Differentiation and Development Center, Marshall University, Huntington, WV 25755, USA
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32
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Fujita Y, Yamashita T. Spatial organization of genome architecture in neuronal development and disease. Neurochem Int 2017; 119:49-56. [PMID: 28757389 DOI: 10.1016/j.neuint.2017.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 06/19/2017] [Accepted: 06/26/2017] [Indexed: 01/19/2023]
Abstract
Although mammalian genomes encode genetic information in their linear sequences, their fundamental function with regard to gene expression depends on the higher-order structure of chromosomes. Current techniques for the evaluation of chromosomal structure have revealed that genomes are arranged at several hierarchical levels in three-dimensional space. The spatial organization of genomes involves the formation of chromatin loops that bypass a wide range of genomic distances, providing a connection between enhancers and chromosomal domains. Furthermore, they form chromatin domains that are arranged into chromosome territories in the three-dimensional space of the cell nucleus. Recent studies have shown that the spatial organization of the genome is essential for normal brain development and function. Activity-dependent alterations in the spatial organization of the genome can regulate transcriptional activity related to neuronal plasticity. Disruptions in the higher-order chromatin architecture have been implicated in neuropsychiatric disorders, such as cognitive dysfunction and anxiety. Here, we discuss the growing interest in the role of genome organization in brain development and neurological disorders.
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Affiliation(s)
- Yuki Fujita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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33
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Pandey S, Pruitt K. Functional assessment of MeCP2 in Rett syndrome and cancers of breast, colon, and prostate. Biochem Cell Biol 2017; 95:368-378. [DOI: 10.1139/bcb-2016-0154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Ever since the first report that mutations in methyl-CpG-binding protein 2 (MeCP2) causes Rett syndrome (RTT), a severe neurological disorder in females world-wide, there has been a keen interest to gain a comprehensive understanding of this protein. While the classical model associated with MeCP2 function suggests its role in gene suppression via recruitment of co-repressor complexes and histone deacetylases to methylated CpG-sites, recent discoveries have brought to light its role in transcription activation, modulation of RNA splicing, and chromatin compaction. Various post-translational modifications (PTMs) of MeCP2 further increase its functional versatility. Involvement of MeCP2 in pathologies other than RTT, such as tumorigenesis however, remains poorly explored and understood. This review provides a survey of the literature implicating MeCP2 in breast, colon and prostate cancer.
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Affiliation(s)
- Somnath Pandey
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Kevin Pruitt
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
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34
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Schenkel LC, Kernohan KD, McBride A, Reina D, Hodge A, Ainsworth PJ, Rodenhiser DI, Pare G, Bérubé NG, Skinner C, Boycott KM, Schwartz C, Sadikovic B. Identification of epigenetic signature associated with alpha thalassemia/mental retardation X-linked syndrome. Epigenetics Chromatin 2017; 10:10. [PMID: 28293299 PMCID: PMC5345252 DOI: 10.1186/s13072-017-0118-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/01/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Alpha thalassemia/mental retardation X-linked syndrome (ATR-X) is caused by a mutation at the chromatin regulator gene ATRX. The mechanisms involved in the ATR-X pathology are not completely understood, but may involve epigenetic modifications. ATRX has been linked to the regulation of histone H3 and DNA methylation, while mutations in the ATRX gene may lead to the downstream epigenetic and transcriptional effects. Elucidating the underlying epigenetic mechanisms altered in ATR-X will provide a better understanding about the pathobiology of this disease, as well as provide novel diagnostic biomarkers. RESULTS We performed genome-wide DNA methylation assessment of the peripheral blood samples from 18 patients with ATR-X and compared it to 210 controls. We demonstrated the evidence of a unique and highly specific DNA methylation "epi-signature" in the peripheral blood of ATRX patients, which was corroborated by targeted bisulfite sequencing experiments. Although genomically represented, differentially methylated regions showed evidence of preferential clustering in pericentromeric and telometric chromosomal regions, areas where ATRX has multiple functions related to maintenance of heterochromatin and genomic integrity. CONCLUSION Most significant methylation changes in the 14 genomic loci provide a unique epigenetic signature for this syndrome that may be used as a highly sensitive and specific diagnostic biomarker to support the diagnosis of ATR-X, particularly in patients with phenotypic complexity and in patients with ATRX gene sequence variants of unknown significance.
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Affiliation(s)
- Laila C Schenkel
- Department of Pathology and Lab Medicine, Western University, London, ON Canada
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Arran McBride
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Ditta Reina
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Amanda Hodge
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Peter J Ainsworth
- Department of Pathology and Lab Medicine, Western University, London, ON Canada.,Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Center, 800 Commissioner's Road E, B10-104, London, ON N6A 5W9 Canada.,Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - David I Rodenhiser
- Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - Guillaume Pare
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Nathalie G Bérubé
- Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - Cindy Skinner
- Center for Molecular Studies, J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, SC USA
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Charles Schwartz
- Center for Molecular Studies, J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, SC USA
| | - Bekim Sadikovic
- Department of Pathology and Lab Medicine, Western University, London, ON Canada.,Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Center, 800 Commissioner's Road E, B10-104, London, ON N6A 5W9 Canada.,Children's Health Research Institute, London, ON Canada
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35
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MeCP2, A Modulator of Neuronal Chromatin Organization Involved in Rett Syndrome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 978:3-21. [PMID: 28523538 DOI: 10.1007/978-3-319-53889-1_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
From an epigenetic perspective, the genomic chromatin organization of neurons exhibits unique features when compared to somatic cells. Methyl CpG binding protein 2 (MeCP2), through its ability to bind to methylated DNA, seems to be a major player in regulating such unusual organization. An important contribution to this uniqueness stems from the intrinsically disordered nature of this highly abundant chromosomal protein in neurons. Upon its binding to methylated/hydroxymethylated DNA, MeCP2 is able to recruit a plethora of interacting protein and RNA partners. The final outcome is a highly specialized chromatin organization wherein linker histones (histones of the H1 family) and MeCP2 share an organizational role that dynamically changes during neuronal development and that it is still poorly understood. MeCP2 mutations alter its chromatin-binding dynamics and/or impair the ability of the protein to interact with some of its partners, resulting in Rett syndrome (RTT). Therefore, deciphering the molecular details involved in the MeCP2 neuronal chromatin arrangement is critical for our understanding of the proper and altered functionality of these cells.
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36
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Claveria-Gimeno R, Abian O, Velazquez-Campoy A, Ausió J. MeCP2… Nature’s Wonder Protein or Medicine’s Most Feared One? CURRENT GENETIC MEDICINE REPORTS 2016. [DOI: 10.1007/s40142-016-0107-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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37
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Rajarajan P, Gil SE, Brennand KJ, Akbarian S. Spatial genome organization and cognition. Nat Rev Neurosci 2016; 17:681-691. [PMID: 27708356 DOI: 10.1038/nrn.2016.124] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonrandom chromosomal conformations, including promoter-enhancer loopings that bypass kilobases or megabases of linear genome, provide a crucial layer of transcriptional regulation and move vast amounts of non-coding sequence into the physical proximity of genes that are important for neurodevelopment, cognition and behaviour. Activity-regulated changes in the neuronal '3D genome' could govern transcriptional mechanisms associated with learning and plasticity, and loop-bound intergenic and intronic non-coding sequences have been implicated in psychiatric and adult-onset neurodegenerative disease. Recent studies have begun to clarify the roles of spatial genome organization in normal and abnormal cognition.
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Affiliation(s)
- Prashanth Rajarajan
- Department of Psychiatry, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029 New York, USA
| | - Sergio Espeso Gil
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), Plaça de la Mercè 10, Barcelona 08002, Spain
| | - Kristen J Brennand
- Department of Psychiatry, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029 New York, USA
| | - Schahram Akbarian
- Department of Psychiatry, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029 New York, USA
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38
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Liu L, Ling X, Wu M, Chen J, Chen S, Tan Q, Chen J, Liu J, Zou F. Rb silencing mediated by the down-regulation of MeCP2 is involved in cell transformation induced by long-term exposure to hydroquinone. Mol Carcinog 2016; 56:651-663. [DOI: 10.1002/mc.22523] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 06/04/2016] [Accepted: 07/01/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Linhua Liu
- Department of Occupational Health and Occupational Medicine; Guangdong Provincial Key Laboratory of Tropical Disease Research; School of Public Health and Tropical Medicine; Southern Medical University; Guangzhou PR China
- Department of Environmental and Occupational Health; Dongguan Key Laboratory of Environmental Medicine; School of Public Health; Guangdong Medical University; Dongguan PR China
| | - Xiaoxuan Ling
- Department of Environmental and Occupational Health; Dongguan Key Laboratory of Environmental Medicine; School of Public Health; Guangdong Medical University; Dongguan PR China
- School of Public Health; Guangzhou Medical University; Guangzhou PR China
| | - Minhua Wu
- Department of Histology and Embryology; Guangdong Medical University; Zhanjiang PR China
| | - Jialong Chen
- Department of Occupational Health and Occupational Medicine; Guangdong Provincial Key Laboratory of Tropical Disease Research; School of Public Health and Tropical Medicine; Southern Medical University; Guangzhou PR China
- Department of Environmental and Occupational Health; Dongguan Key Laboratory of Environmental Medicine; School of Public Health; Guangdong Medical University; Dongguan PR China
| | - Shaoqiao Chen
- Department of Clinical Laboratory; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou PR China
| | - Qiang Tan
- Foshan Institute of Occupational Disease Prevention and Control; Foshan PR China
| | - Jiansong Chen
- School of Public Health; Guangzhou Medical University; Guangzhou PR China
| | - Jiaxian Liu
- Department of Environmental and Occupational Health; Dongguan Key Laboratory of Environmental Medicine; School of Public Health; Guangdong Medical University; Dongguan PR China
| | - Fei Zou
- Department of Occupational Health and Occupational Medicine; Guangdong Provincial Key Laboratory of Tropical Disease Research; School of Public Health and Tropical Medicine; Southern Medical University; Guangzhou PR China
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39
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Della Ragione F, Vacca M, Fioriniello S, Pepe G, D'Esposito M. MECP2, a multi-talented modulator of chromatin architecture. Brief Funct Genomics 2016; 15:420-431. [PMID: 27296483 DOI: 10.1093/bfgp/elw023] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It has been a long trip from 1992, the year of the discovery of MECP2, to the present day. What is surprising is that some of the pivotal roles of MeCP2 were already postulated at that time, such as repression of inappropriate expression from repetitive elements and the regulation of pericentric heterochromatin condensation. However, MeCP2 performs many more functions. MeCP2 is a reader of epigenetic information contained in methylated (and hydroxymethylated) DNA, moving from the 'classical' CpG doublet to the more complex view addressed by the non-CpG methylation, which is a feature of the postnatal brain. MECP2 is a transcriptional repressor, although when it forms complexes with the appropriate molecules, it can become a transcriptional activator. For all of these aspects, Rett syndrome, which is caused by MECP2 mutations, is considered a paradigmatic example of a 'chromatin disorder'. Even if the hunt for bona-fide MECP2 target genes is far from concluded today, the role of MeCP2 in the maintenance of chromatin architecture appears to be clearly established. Taking a cue from the non-scientific literature, we can firmly attest that MeCP2 is a player with 'a great future behind it'*.*V. Gassmann 'Un grande avvenire dietro le spalle'. TEA Eds.
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40
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Comino-Méndez I, Tejera ÁM, Currás-Freixes M, Remacha L, Gonzalvo P, Tonda R, Letón R, Blasco MA, Robledo M, Cascón A. ATRX driver mutation in a composite malignant pheochromocytoma. Cancer Genet 2016; 209:272-7. [PMID: 27209355 DOI: 10.1016/j.cancergen.2016.04.058] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/01/2016] [Accepted: 04/23/2016] [Indexed: 12/19/2022]
Abstract
Pheochromocytomas (PCCs) and paragangliomas (PGLs) are tumors arising from the adrenal medulla and sympathetic/parasympathetic paraganglia, respectively. Approximately 40% of PCCs/PGLs are due to germline mutations in one of 16 susceptibility genes, and a further 30% are due to somatic alterations in 5 main genes. Recently, somatic ATRX mutations have been found in succinate dehydrogenase (SDH)-associated hereditary PCCs/PGLs. In the present study we applied whole-exome sequencing to the germline and tumor DNA of a patient with metastatic composite PCC and no alterations in known PCC/PGL susceptibility genes. A somatic loss-of-function mutation affecting ATRX was identified in tumor DNA. Transcriptional profiling analysis classified the tumor within cluster 2 of PCCs/PGLs (without SDH gene mutations) and identified downregulation of genes involved in neuronal development and homeostasis (NLGN4, CD99 and CSF2RA) as well as upregulation of Drosha, an important gene involved in miRNA and rRNA processing. CpG island methylator phenotype typical of SDH gene-mutated tumors was ruled out, and SNP array data revealed a unique profile of gains and losses. Finally, we demonstrated the presence of alternative lengthening of telomeres in the tumor, probably associated with the failure of ATRX functions. In conclusion, somatic variants affecting ATRX may play a driver role in sporadic PCC/PGL.
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Affiliation(s)
- Iñaki Comino-Méndez
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Águeda M Tejera
- Telomeres and Telomerase Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - María Currás-Freixes
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Laura Remacha
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Pablo Gonzalvo
- Department of Anatomical Pathology, Cabueñes Hospital, Gijón, Spain
| | - Raúl Tonda
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Rocío Letón
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - María A Blasco
- Telomeres and Telomerase Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Mercedes Robledo
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Alberto Cascón
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
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41
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Li Y, Syed J, Suzuki Y, Asamitsu S, Shioda N, Wada T, Sugiyama H. Effect of ATRX and G-Quadruplex Formation by the VNTR Sequence on α-Globin Gene Expression. Chembiochem 2016; 17:928-35. [DOI: 10.1002/cbic.201500655] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Yue Li
- Department of Chemistry; Graduate School of Science; Kyoto University; Kyoto 606-8502 Japan
| | - Junetha Syed
- Department of Chemistry; Graduate School of Science; Kyoto University; Kyoto 606-8502 Japan
| | - Yuki Suzuki
- Department of Chemistry; Graduate School of Science; Kyoto University; Kyoto 606-8502 Japan
| | - Sefan Asamitsu
- Department of Chemistry; Graduate School of Science; Kyoto University; Kyoto 606-8502 Japan
| | - Norifumi Shioda
- Department of Pharmacology; Graduate School of Pharmaceutical Sciences; Tohoku University; Sendai 980-8578 Japan
| | - Takahito Wada
- Department of Medical Ethics and Medical Genetics; Graduate School of Medicine; Kyoto University; Kyoto 606-8501 Japan
| | - Hiroshi Sugiyama
- Department of Chemistry; Graduate School of Science; Kyoto University; Kyoto 606-8502 Japan
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS); Kyoto University; Kyoto 606-8501 Japan
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42
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Winick-Ng W, Caetano FA, Winick-Ng J, Morey TM, Heit B, Rylett RJ. 82-kDa choline acetyltransferase and SATB1 localize to β-amyloid induced matrix attachment regions. Sci Rep 2016; 6:23914. [PMID: 27052102 PMCID: PMC4823725 DOI: 10.1038/srep23914] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/16/2016] [Indexed: 01/29/2023] Open
Abstract
The M-transcript of human choline acetyltransferase (ChAT) produces an 82-kDa protein (82-kDa ChAT) that concentrates in nuclei of cholinergic neurons. We assessed the effects of acute exposure to oligomeric amyloid-β1–42 (Aβ1–42) on 82-kDa ChAT disposition in SH-SY5Y neural cells, finding that acute exposure to Aβ1–42 results in increased association of 82-kDa ChAT with chromatin and formation of 82-kDa ChAT aggregates in nuclei. When measured by chromatin immunoprecipitation with next-generation sequencing (ChIP-seq), we identified that Aβ1–42 -exposure increases 82-kDa ChAT association with gene promoters and introns. The Aβ1–42 -induced 82-kDa ChAT aggregates co-localize with special AT-rich binding protein 1 (SATB1), which anchors DNA to scaffolding/matrix attachment regions (S/MARs). SATB1 had a similar genomic association as 82-kDa ChAT, with both proteins associating with synapse and cell stress genes. After Aβ1–42 -exposure, both SATB1 and 82-kDa ChAT are enriched at the same S/MAR on the APP gene, with 82-kDa ChAT expression attenuating an increase in an isoform-specific APP mRNA transcript. Finally, 82-kDa ChAT and SATB1 have patterned genomic association at regions enriched with S/MAR binding motifs. These results demonstrate that 82-kDa ChAT and SATB1 play critical roles in the response of neural cells to acute Aβ -exposure.
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Affiliation(s)
- Warren Winick-Ng
- Department of Physiology and Pharmacology, Schulich School of Medicine &Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 Canada.,Molecular Medicine Group, Robarts Research Institute, University of Western Ontario, London, Ontario, N6A 5C1 Canada
| | - Fabiana A Caetano
- Department of Physiology and Pharmacology, Schulich School of Medicine &Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 Canada.,Molecular Medicine Group, Robarts Research Institute, University of Western Ontario, London, Ontario, N6A 5C1 Canada
| | | | - Trevor M Morey
- Department of Physiology and Pharmacology, Schulich School of Medicine &Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 Canada.,Molecular Medicine Group, Robarts Research Institute, University of Western Ontario, London, Ontario, N6A 5C1 Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, Schulich School of Medicine &Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 Canada
| | - R Jane Rylett
- Department of Physiology and Pharmacology, Schulich School of Medicine &Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 Canada.,Molecular Medicine Group, Robarts Research Institute, University of Western Ontario, London, Ontario, N6A 5C1 Canada
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43
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Wenderski W, Maze I. Histone turnover and chromatin accessibility: Critical mediators of neurological development, plasticity, and disease. Bioessays 2016; 38:410-9. [PMID: 26990528 DOI: 10.1002/bies.201500171] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In postmitotic neurons, nucleosomal turnover was long considered to be a static process that is inconsequential to transcription. However, our recent studies in human and rodent brain indicate that replication-independent (RI) nucleosomal turnover, which requires the histone variant H3.3, is dynamic throughout life and is necessary for activity-dependent gene expression, synaptic connectivity, and cognition. H3.3 turnover also facilitates cellular lineage specification and plays a role in suppressing the expression of heterochromatic repetitive elements, including mutagenic transposable sequences, in mouse embryonic stem cells. In this essay, we review mechanisms and functions for RI nucleosomal turnover in brain and present the hypothesis that defects in histone dynamics may represent a common mechanism underlying neurological aging and disease.
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Affiliation(s)
- Wendy Wenderski
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Ian Maze
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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44
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Matelot M, Noordermeer D. Determination of High-Resolution 3D Chromatin Organization Using Circular Chromosome Conformation Capture (4C-seq). Methods Mol Biol 2016; 1480:223-41. [PMID: 27659989 DOI: 10.1007/978-1-4939-6380-5_20] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
3D chromatin organization is essential for many aspects of transcriptional regulation. Circular Chromosome Conformation Capture followed by Illumina sequencing (4C-seq) is among the most powerful techniques to determine 3D chromatin organization. 4C-seq, like other modifications of the original 3C technique, uses the principle of "proximity ligation" to identify and quantify ten thousands of genomic interactions at a kilobase scale in a single experiment for predefined loci in the genome.In this chapter we focus on the experimental steps in the 4C-seq protocol, providing detailed descriptions on the preparation of cells, the construction of the circularized 3C library and the generation of the Illumina high throughput sequencing library. This protocol is particularly suited for the use of mammalian tissue samples, but can be used with minimal changes on circulating cells and cell lines from other sources as well. In the final section of this chapter, we provide a brief overview of data analysis approaches, accompanied by links to publicly available analysis tools.
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Affiliation(s)
- Mélody Matelot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, University Paris-Saclay, 1 Avenue de la terrasse, 91198, Gif sur Yvette, France
| | - Daan Noordermeer
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, University Paris-Saclay, 1 Avenue de la terrasse, 91198, Gif sur Yvette, France.
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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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46
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Pandey S, Simmons GE, Malyarchuk S, Calhoun TN, Pruitt K. A novel MeCP2 acetylation site regulates interaction with ATRX and HDAC1. Genes Cancer 2015; 6:408-21. [PMID: 26622943 PMCID: PMC4633168 DOI: 10.18632/genesandcancer.84] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Methyl-CpG-binding protein-2 (MeCP2) regulates gene expression by recruiting SWI/SNF DNA helicase/ATPase (ATRX) and Histone Deacetylase-1 (HDAC1) to methylated gene regions and modulates heterochromatin association by interacting with Heterochromatin protein-1. As MeCP2 contributes to tumor suppressor gene silencing and its mutation causes Rett Syndrome, we investigated how novel post-translational-modification contributes to its function. Herein we report that upon pharmacological inhibition of SIRT1 in RKO colon and MCF-7 breast cancer cells, endogenous MeCP2 is acetylated at sites critical for binding to DNA and transcriptional regulators. We created an acetylation mimetic mutation in MeCP2 and found it to possess decreased binding to ATRX and HDAC1. Conditions inducing MeCP2 acetylation do not alter its promoter occupancy at a subset of target genes analyzed, but do cause decreased binding to ATRX and HDAC1. We also report here that a specific inhibitor of SIRT1, IV, can be used to selectively decrease H3K27me3 repressive marks on a subset of repressed target gene promoters analyzed. Lastly, we show that RKO cells over-expressing MeCP2 mutant show reduced proliferation compared to those over-expressing MeCP2-wildtype. Our study demonstrates the importance of acetylated lysine residues and suggests their key role in regulating MeCP2 function and its ability to bind transcriptional regulators.
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Affiliation(s)
- Somnath Pandey
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Glenn E Simmons
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Svitlana Malyarchuk
- Molecular and Cellular Physiology, Shreveport, LA, USA ; LSU Health Sciences Center School of Medicine, Shreveport, LA, USA
| | - Tara N Calhoun
- Molecular and Cellular Physiology, Shreveport, LA, USA ; LSU Health Sciences Center School of Medicine, Shreveport, LA, USA
| | - Kevin Pruitt
- Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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47
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Du Q, Luu PL, Stirzaker C, Clark SJ. Methyl-CpG-binding domain proteins: readers of the epigenome. Epigenomics 2015; 7:1051-73. [DOI: 10.2217/epi.15.39] [Citation(s) in RCA: 265] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How DNA methylation is interpreted and influences genome regulation remains largely unknown. Proteins of the methyl-CpG-binding domain (MBD) family are primary candidates for the readout of DNA methylation as they recruit chromatin remodelers, histone deacetylases and methylases to methylated DNA associated with gene repression. MBD protein binding requires both functional MBD domains and methyl-CpGs; however, some MBD proteins also bind unmethylated DNA and active regulatory regions via alternative regulatory domains or interaction with the nucleosome remodeling deacetylase (NuRD/Mi-2) complex members. Mutations within MBD domains occur in many diseases, including neurological disorders and cancers, leading to loss of MBD binding specificity to methylated sites and gene deregulation. Here, we summarize the current state of knowledge about MBD proteins and their role as readers of the epigenome.
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Affiliation(s)
- Qian Du
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Phuc-Loi Luu
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Clare Stirzaker
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
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Abstract
Two severe, progressive neurological disorders characterized by intellectual disability, autism, and developmental regression, Rett syndrome and MECP2 duplication syndrome, result from loss and gain of function, respectively, of the same critical gene, methyl-CpG-binding protein 2 (MECP2). Neurons acutely require the appropriate dose of MECP2 to function properly but do not die in its absence or overexpression. Instead, neuronal dysfunction can be reversed in a Rett syndrome mouse model if MeCP2 function is restored. Thus, MECP2 disorders provide a unique window into the delicate balance of neuronal health, the power of mouse models, and the importance of chromatin regulation in mature neurons. In this Review, we will discuss the clinical profiles of MECP2 disorders, the knowledge acquired from mouse models of the syndromes, and how that knowledge is informing current and future clinical studies.
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Voon HPJ, Hughes JR, Rode C, De La Rosa-Velázquez IA, Jenuwein T, Feil R, Higgs DR, Gibbons RJ. ATRX Plays a Key Role in Maintaining Silencing at Interstitial Heterochromatic Loci and Imprinted Genes. Cell Rep 2015; 11:405-18. [PMID: 25865896 PMCID: PMC4410944 DOI: 10.1016/j.celrep.2015.03.036] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/30/2015] [Accepted: 03/14/2015] [Indexed: 11/27/2022] Open
Abstract
Histone H3.3 is a replication-independent histone variant, which replaces histones that are turned over throughout the entire cell cycle. H3.3 deposition at euchromatin is dependent on HIRA, whereas ATRX/Daxx deposits H3.3 at pericentric heterochromatin and telomeres. The role of H3.3 at heterochromatic regions is unknown, but mutations in the ATRX/Daxx/H3.3 pathway are linked to aberrant telomere lengthening in certain cancers. In this study, we show that ATRX-dependent deposition of H3.3 is not limited to pericentric heterochromatin and telomeres but also occurs at heterochromatic sites throughout the genome. Notably, ATRX/H3.3 specifically localizes to silenced imprinted alleles in mouse ESCs. ATRX KO cells failed to deposit H3.3 at these sites, leading to loss of the H3K9me3 heterochromatin modification, loss of repression, and aberrant allelic expression. We propose a model whereby ATRX-dependent deposition of H3.3 into heterochromatin is normally required to maintain the memory of silencing at imprinted loci. ATRX deposits H3.3 at heterochromatin throughout the genome ATRX and H3.3 preferentially bind the methylated allele of imprinted DMRs H3.3 deposition at imprinted DMRs is dependent on ATRX Loss of ATRX/H3.3 leads to loss of H3K9me3 modification at imprinted DMRs
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Affiliation(s)
- Hsiao P J Voon
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Christina Rode
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | | | - Thomas Jenuwein
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de la Recherche Scientifique (CNRS), 34293 Montpellier, France
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Richard J Gibbons
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
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50
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Levy MA, Kernohan KD, Jiang Y, Bérubé NG. ATRX promotes gene expression by facilitating transcriptional elongation through guanine-rich coding regions. Hum Mol Genet 2014; 24:1824-35. [PMID: 25452430 DOI: 10.1093/hmg/ddu596] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
ATRX is a chromatin remodeling protein involved in deposition of the histone variant H3.3 at telomeres and pericentromeric heterochromatin. It also influences the expression level of specific genes; however, deposition of H3.3 at transcribed genes is currently thought to occur independently of ATRX. We focused on a set of genes, including the autism susceptibility gene Neuroligin 4 (Nlgn4), that exhibit decreased expression in ATRX-null cells to investigate the mechanisms used by ATRX to promote gene transcription. Overall TERRA levels, as well as DNA methylation and histone modifications at ATRX target genes are not altered and thus cannot explain transcriptional dysregulation. We found that ATRX does not associate with the promoter of these genes, but rather binds within regions of the gene body corresponding to high H3.3 occupancy. These intragenic regions consist of guanine-rich DNA sequences predicted to form non-B DNA structures called G-quadruplexes during transcriptional elongation. We demonstrate that ATRX deficiency corresponds to reduced H3.3 incorporation and stalling of RNA polymerase II at these G-rich intragenic sites. These findings suggest that ATRX promotes the incorporation of histone H3.3 at particular transcribed genes and facilitates transcriptional elongation through G-rich sequences. The inability to transcribe genes such as Nlgn4 could cause deficits in neuronal connectivity and cognition associated with ATRX mutations in humans.
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Affiliation(s)
- Michael A Levy
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1, Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1 Children's Health Research Institute, London, Ontario, Canada N6C 2V5
| | - Kristin D Kernohan
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1, Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1 Children's Health Research Institute, London, Ontario, Canada N6C 2V5
| | - Yan Jiang
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1, Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1 Children's Health Research Institute, London, Ontario, Canada N6C 2V5
| | - Nathalie G Bérubé
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1, Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5C1 Children's Health Research Institute, London, Ontario, Canada N6C 2V5
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