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Budzko L, Hoffa-Sobiech K, Jackowiak P, Figlerowicz M. Engineered deaminases as a key component of DNA and RNA editing tools. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 34:102062. [PMID: 38028200 PMCID: PMC10661471 DOI: 10.1016/j.omtn.2023.102062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Over recent years, zinc-dependent deaminases have attracted increasing interest as key components of nucleic acid editing tools that can generate point mutations at specific sites in either DNA or RNA by combining a targeting module (such as a catalytically impaired CRISPR-Cas component) and an effector module (most often a deaminase). Deaminase-based molecular tools are already being utilized in a wide spectrum of therapeutic and research applications; however, their medical and biotechnological potential seems to be much greater. Recent reports indicate that the further development of nucleic acid editing systems depends largely on our ability to engineer the substrate specificity and catalytic activity of the editors themselves. In this review, we summarize the current trends and achievements in deaminase engineering. The presented data indicate that the potential of these enzymes has not yet been fully revealed or understood. Several examples show that even relatively minor changes in the structure of deaminases can give them completely new and unique properties.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Karolina Hoffa-Sobiech
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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2
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Jiao J, Lv Z, Wang Y, Fan L, Yang A. The off-target effects of AID in carcinogenesis. Front Immunol 2023; 14:1221528. [PMID: 37600817 PMCID: PMC10436223 DOI: 10.3389/fimmu.2023.1221528] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) plays a crucial role in promoting B cell diversification through somatic hypermutation (SHM) and class switch recombination (CSR). While AID is primarily associated with the physiological function of humoral immune response, it has also been linked to the initiation and progression of lymphomas. Abnormalities in AID have been shown to disrupt gene networks and signaling pathways in both B-cell and T-cell lineage lymphoblastic leukemia, although the full extent of its role in carcinogenesis remains unclear. This review proposes an alternative role for AID and explores its off-target effects in regulating tumorigenesis. In this review, we first provide an overview of the physiological function of AID and its regulation. AID plays a crucial role in promoting B cell diversification through SHM and CSR. We then discuss the off-target effects of AID, which includes inducing mutations of non-Igs, epigenetic modification, and the alternative role as a cofactor. We also explore the networks that keep AID in line. Furthermore, we summarize the off-target effects of AID in autoimmune diseases and hematological neoplasms. Finally, we assess the off-target effects of AID in solid tumors. The primary focus of this review is to understand how and when AID targets specific gene loci and how this affects carcinogenesis. Overall, this review aims to provide a comprehensive understanding of the physiological and off-target effects of AID, which will contribute to the development of novel therapeutic strategies for autoimmune diseases, hematological neoplasms, and solid tumors.
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Affiliation(s)
- Junna Jiao
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, China
| | - Zhuangwei Lv
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yurong Wang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, China
| | - Liye Fan
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, China
| | - Angang Yang
- Henan Key Laboratory of Immunology and Targeted Therapy, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, Henan, China
- The State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, Shaanxi, China
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, Henan, China
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3
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Lirussi L, Nilsen HL. DNA Glycosylases Define the Outcome of Endogenous Base Modifications. Int J Mol Sci 2023; 24:10307. [PMID: 37373453 DOI: 10.3390/ijms241210307] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Chemically modified nucleic acid bases are sources of genomic instability and mutations but may also regulate gene expression as epigenetic or epitranscriptomic modifications. Depending on the cellular context, they can have vastly diverse impacts on cells, from mutagenesis or cytotoxicity to changing cell fate by regulating chromatin organisation and gene expression. Identical chemical modifications exerting different functions pose a challenge for the cell's DNA repair machinery, as it needs to accurately distinguish between epigenetic marks and DNA damage to ensure proper repair and maintenance of (epi)genomic integrity. The specificity and selectivity of the recognition of these modified bases relies on DNA glycosylases, which acts as DNA damage, or more correctly, as modified bases sensors for the base excision repair (BER) pathway. Here, we will illustrate this duality by summarizing the role of uracil-DNA glycosylases, with particular attention to SMUG1, in the regulation of the epigenetic landscape as active regulators of gene expression and chromatin remodelling. We will also describe how epigenetic marks, with a special focus on 5-hydroxymethyluracil, can affect the damage susceptibility of nucleic acids and conversely how DNA damage can induce changes in the epigenetic landscape by altering the pattern of DNA methylation and chromatin structure.
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Affiliation(s)
- Lisa Lirussi
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Section of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway
| | - Hilde Loge Nilsen
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway
- Unit for Precision Medicine, Akershus University Hospital, 1478 Lørenskog, Norway
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4
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Baljinnyam T, Sowers ML, Hsu CW, Conrad JW, Herring JL, Hackfeld LC, Sowers LC. Chemical and enzymatic modifications of 5-methylcytosine at the intersection of DNA damage, repair, and epigenetic reprogramming. PLoS One 2022; 17:e0273509. [PMID: 36037209 PMCID: PMC9423628 DOI: 10.1371/journal.pone.0273509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 08/09/2022] [Indexed: 11/19/2022] Open
Abstract
The DNA of all living organisms is persistently damaged by endogenous reactions including deamination and oxidation. Such damage, if not repaired correctly, can result in mutations that drive tumor development. In addition to chemical damage, recent studies have established that DNA bases can be enzymatically modified, generating many of the same modified bases. Irrespective of the mechanism of formation, modified bases can alter DNA-protein interactions and therefore modulate epigenetic control of gene transcription. The simultaneous presence of both chemically and enzymatically modified bases in DNA suggests a potential intersection, or collision, between DNA repair and epigenetic reprogramming. In this paper, we have prepared defined sequence oligonucleotides containing the complete set of oxidized and deaminated bases that could arise from 5-methylcytosine. We have probed these substrates with human glycosylases implicated in DNA repair and epigenetic reprogramming. New observations reported here include: SMUG1 excises 5-carboxyuracil (5caU) when paired with A or G. Both TDG and MBD4 cleave 5-formyluracil and 5caU when mispaired with G. Further, TDG not only removes 5-formylcytosine and 5-carboxycytosine when paired with G, but also when mispaired with A. Surprisingly, 5caU is one of the best substrates for human TDG, SMUG1 and MBD4, and a much better substrate than T. The data presented here introduces some unexpected findings that pose new questions on the interactions between endogenous DNA damage, repair, and epigenetic reprogramming pathways.
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Affiliation(s)
- Tuvshintugs Baljinnyam
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Mark L. Sowers
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Chia Wei Hsu
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - James W. Conrad
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jason L. Herring
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Linda C. Hackfeld
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lawrence C. Sowers
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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5
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Structure and Function of TET Enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:239-267. [DOI: 10.1007/978-3-031-11454-0_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Wang T, Loo CE, Kohli RM. Enzymatic approaches for profiling cytosine methylation and hydroxymethylation. Mol Metab 2021; 57:101314. [PMID: 34375743 PMCID: PMC8829811 DOI: 10.1016/j.molmet.2021.101314] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/26/2021] [Accepted: 08/03/2021] [Indexed: 12/20/2022] Open
Abstract
Background In mammals, modifications to cytosine bases, particularly in cytosine-guanine (CpG) dinucleotide contexts, play a major role in shaping the epigenome. The canonical epigenetic mark is 5-methylcytosine (5mC), but oxidized versions of 5mC, including 5-hydroxymethylcytosine (5hmC), are now known to be important players in epigenomic dynamics. Understanding the functional role of these modifications in gene regulation, normal development, and pathological conditions requires the ability to localize these modifications in genomic DNA. The classical approach for sequencing cytosine modifications has involved differential deamination via the chemical sodium bisulfite; however, bisulfite is destructive, limiting its utility in important biological or clinical settings where detection of low frequency populations is critical. Additionally, bisulfite fails to resolve 5mC from 5hmC. Scope of review To summarize how enzymatic rather than chemical approaches can be leveraged to localize and resolve different cytosine modifications in a non-destructive manner. Major conclusions Nature offers a suite of enzymes with biological roles in cytosine modification in organisms spanning from bacteriophages to mammals. These enzymatic activities include methylation by DNA methyltransferases, oxidation of 5mC by TET family enzymes, hypermodification of 5hmC by glucosyltransferases, and the generation of transition mutations from cytosine to uracil by DNA deaminases. Here, we describe how insights into the natural reactivities of these DNA-modifying enzymes can be leveraged to convert them into powerful biotechnological tools. Application of these enzymes in sequencing can be accomplished by relying on their natural activity, exploiting their ability to discriminate between cytosine modification states, reacting them with functionalized substrate analogs to introduce chemical handles, or engineering the DNA-modifying enzymes to take on new reactivities. We describe how these enzymatic reactions have been combined and permuted to localize DNA modifications with high specificity and without the destructive limitations posed by chemical methods for epigenetic sequencing. Chemical sequencing methods damage DNA and can confound cytosine modifications. DNA modifying enzymes offer non-destructive and selective biotechnological tools. DNA deaminases, methyltransferases, oxygenases and glucosyltransferases can be used. Permuting enzymes with various activities can reveal distinct cytosine states. Engineered enzymes utilizing unnatural co-substrates expand sequencing scope.
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Affiliation(s)
- Tong Wang
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christian E Loo
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahul M Kohli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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7
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Bray JK, Dawlaty MM, Verma A, Maitra A. Roles and Regulations of TET Enzymes in Solid Tumors. Trends Cancer 2021; 7:635-646. [PMID: 33468438 DOI: 10.1016/j.trecan.2020.12.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 01/09/2023]
Abstract
The mechanisms governing the methylome profile of tumor suppressors and oncogenes have expanded with the discovery of oxidized states of 5-methylcytosine (5mC). Ten-eleven translocation (TET) enzymes are a family of dioxygenases that iteratively catalyze 5mC oxidation and promote cytosine demethylation, thereby creating a dynamic global and local methylation landscape. While the catalytic function of TET enzymes during stem cell differentiation and development have been well studied, less is known about the multifaceted roles of TET enzymes during carcinogenesis. This review outlines several tiers of TET regulation and overviews how TET deregulation promotes a cancer phenotype. Defining the tissue-specific and context-dependent roles of TET enzymes will deepen our understanding of the epigenetic perturbations that promote or inhibit carcinogenesis.
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Affiliation(s)
- Julie K Bray
- Sheikh Ahmed Center for Pancreatic Cancer Research, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Amit Verma
- Albert Einstein College of Medicine, New York City, NY, USA
| | - Anirban Maitra
- Sheikh Ahmed Center for Pancreatic Cancer Research, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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8
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Brabson JP, Leesang T, Mohammad S, Cimmino L. Epigenetic Regulation of Genomic Stability by Vitamin C. Front Genet 2021; 12:675780. [PMID: 34017357 PMCID: PMC8129186 DOI: 10.3389/fgene.2021.675780] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/06/2021] [Indexed: 12/24/2022] Open
Abstract
DNA methylation plays an important role in the maintenance of genomic stability. Ten-eleven translocation proteins (TETs) are a family of iron (Fe2+) and α-KG -dependent dioxygenases that regulate DNA methylation levels by oxidizing 5-methylcystosine (5mC) to generate 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). These oxidized methylcytosines promote passive demethylation upon DNA replication, or active DNA demethylation, by triggering base excision repair and replacement of 5fC and 5caC with an unmethylated cytosine. Several studies over the last decade have shown that loss of TET function leads to DNA hypermethylation and increased genomic instability. Vitamin C, a cofactor of TET enzymes, increases 5hmC formation and promotes DNA demethylation, suggesting that this essential vitamin, in addition to its antioxidant properties, can also directly influence genomic stability. This review will highlight the functional role of DNA methylation, TET activity and vitamin C, in the crosstalk between DNA methylation and DNA repair.
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Affiliation(s)
- John P Brabson
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Tiffany Leesang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Sofia Mohammad
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Luisa Cimmino
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States.,Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
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9
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Bordin DL, Lirussi L, Nilsen H. Cellular response to endogenous DNA damage: DNA base modifications in gene expression regulation. DNA Repair (Amst) 2021; 99:103051. [PMID: 33540225 DOI: 10.1016/j.dnarep.2021.103051] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/19/2022]
Abstract
The integrity of the genetic information is continuously challenged by numerous genotoxic insults, most frequently in the form of oxidation, alkylation or deamination of the bases that result in DNA damage. These damages compromise the fidelity of the replication, and interfere with the progression and function of the transcription machineries. The DNA damage response (DDR) comprises a series of strategies to deal with DNA damage, including transient transcriptional inhibition, activation of DNA repair pathways and chromatin remodeling. Coordinated control of transcription and DNA repair is required to safeguardi cellular functions and identities. Here, we address the cellular responses to endogenous DNA damage, with a particular focus on the role of DNA glycosylases and the Base Excision Repair (BER) pathway, in conjunction with the DDR factors, in responding to DNA damage during the transcription process. We will also discuss functions of newly identified epigenetic and regulatory marks, such as 5-hydroxymethylcytosine and its oxidative products and 8-oxoguanine, that were previously considered only as DNA damages. In light of these resultsthe classical perception of DNA damage as detrimental for cellular processes are changing. and a picture emerges whereDNA glycosylases act as dynamic regulators of transcription, placing them at the intersection of DNA repair and gene expression modulation.
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Affiliation(s)
- Diana L Bordin
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway
| | - Lisa Lirussi
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway.
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10
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Rosikiewicz W, Chen X, Dominguez PM, Ghamlouch H, Aoufouchi S, Bernard OA, Melnick A, Li S. TET2 deficiency reprograms the germinal center B cell epigenome and silences genes linked to lymphomagenesis. SCIENCE ADVANCES 2020; 6:eaay5872. [PMID: 32596441 PMCID: PMC7299612 DOI: 10.1126/sciadv.aay5872] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 03/25/2020] [Indexed: 05/22/2023]
Abstract
The TET2 DNA hydroxymethyltransferase is frequently disrupted by somatic mutations in diffuse large B cell lymphomas (DLBCLs), a tumor that originates from germinal center (GC) B cells. Here, we show that TET2 deficiency leads to DNA hypermethylation of regulatory elements in GC B cells, associated with silencing of the respective genes. This hypermethylation affects the binding of transcription factors including those involved in exit from the GC reaction and involves pathways such as B cell receptor, antigen presentation, CD40, and others. Normal GC B cells manifest a typical hypomethylation signature, which is caused by AID, the enzyme that mediates somatic hypermutation. However, AID-induced demethylation is markedly impaired in TET2-deficient GC B cells, suggesting that AID epigenetic effects are partially dependent on TET2. Last, we find that TET2 mutant DLBCLs also manifest the aberrant TET2-deficient GC DNA methylation signature, suggesting that this epigenetic pattern is maintained during and contributes to lymphomagenesis.
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Affiliation(s)
- Wojciech Rosikiewicz
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
- Center for Applied Bioinformatics, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Xiaowen Chen
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Pilar M. Dominguez
- Department of Medicine, Division of Hematology and Medical Oncology, Weill Cornell Medicine, New York, NY, USA
| | - Hussein Ghamlouch
- INSERM U1170, équipe labelisée Ligue Nationale Contre le Cancer, Gustave Roussy, Université Paris-Saclay, Villejuif, France
| | - Said Aoufouchi
- CNRS UMR8200, équipe labelisée Ligue Nationale Contre le Cancer, Gustave Roussy, Université Paris-Saclay, Villejuif, France
| | - Olivier A. Bernard
- INSERM U1170, équipe labelisée Ligue Nationale Contre le Cancer, Gustave Roussy, Université Paris-Saclay, Villejuif, France
| | - Ari Melnick
- Department of Medicine, Division of Hematology and Medical Oncology, Weill Cornell Medicine, New York, NY, USA
| | - Sheng Li
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
- The Jackson Laboratory Cancer Center, Bar Harbor, ME, USA
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT, USA
- Department of Computer Science and Engineering, University of Connecticut, Storrs, CT, USA
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11
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Kvach MV, Barzak FM, Harjes S, Schares HAM, Kurup HM, Jones KF, Sutton L, Donahue J, D'Aquila RT, Jameson GB, Harki DA, Krause KL, Harjes E, Filichev VV. Differential Inhibition of APOBEC3 DNA-Mutator Isozymes by Fluoro- and Non-Fluoro-Substituted 2'-Deoxyzebularine Embedded in Single-Stranded DNA. Chembiochem 2019; 21:1028-1035. [PMID: 31633265 PMCID: PMC7142307 DOI: 10.1002/cbic.201900505] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/20/2019] [Indexed: 12/17/2022]
Abstract
The APOBEC3 (APOBEC3A‐H) enzyme family is part of the human innate immune system that restricts pathogens by scrambling pathogenic single‐stranded (ss) DNA by deamination of cytosines to produce uracil residues. However, APOBEC3‐mediated mutagenesis of viral and cancer DNA promotes its evolution, thus enabling disease progression and the development of drug resistance. Therefore, APOBEC3 inhibition offers a new strategy to complement existing antiviral and anticancer therapies by making such therapies effective for longer periods of time, thereby preventing the emergence of drug resistance. Here, we have synthesised 2′‐deoxynucleoside forms of several known inhibitors of cytidine deaminase (CDA), incorporated them into oligodeoxynucleotides (oligos) in place of 2′‐deoxycytidine in the preferred substrates of APOBEC3A, APOBEC3B, and APOBEC3G, and evaluated their inhibitory potential against these enzymes. An oligo containing a 5‐fluoro‐2′‐deoxyzebularine (5FdZ) motif exhibited an inhibition constant against APOBEC3B 3.5 times better than that of the comparable 2′‐deoxyzebularine‐containing (dZ‐containing) oligo. A similar inhibition trend was observed for wild‐type APOBEC3A. In contrast, use of the 5FdZ motif in an oligo designed for APOBEC3G inhibition resulted in an inhibitor that was less potent than the dZ‐containing oligo both in the case of APOBEC3GCTD and in that of full‐length wild‐type APOBEC3G.
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Affiliation(s)
- Maksim V Kvach
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand
| | - Fareeda M Barzak
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand
| | - Stefan Harjes
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand
| | - Henry A M Schares
- Department of Medicinal Chemistry, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Harikrishnan M Kurup
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland, 1142, New Zealand
| | - Katherine F Jones
- Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, MN, 55455, USA
| | - Lorraine Sutton
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University School of Medicine, 21st Ave S, Nashville, TN, 37232, USA
| | - John Donahue
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University School of Medicine, 21st Ave S, Nashville, TN, 37232, USA
| | - Richard T D'Aquila
- Division of Infectious Diseases and, Northwestern HIV Translational Research Center, Department of Medicine, Northwestern University Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2330, Chicago, IL, 60611, USA
| | - Geoffrey B Jameson
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland, 1142, New Zealand
| | - Daniel A Harki
- Department of Medicinal Chemistry, University of Minnesota, 2231 6th Street SE, Minneapolis, MN, 55455, USA.,Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, MN, 55455, USA
| | - Kurt L Krause
- Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland, 1142, New Zealand.,Department of Biochemistry, University of Otago, P. O. Box 56, Dunedin, 9054, New Zealand
| | - Elena Harjes
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland, 1142, New Zealand
| | - Vyacheslav V Filichev
- School of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland, 1142, New Zealand
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12
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Tepper S, Mortusewicz O, Członka E, Bello A, Schmidt A, Jeschke J, Fischbach A, Pfeil I, Petersen-Mahrt SK, Mangerich A, Helleday T, Leonhardt H, Jungnickel B. Restriction of AID activity and somatic hypermutation by PARP-1. Nucleic Acids Res 2019; 47:7418-7429. [PMID: 31127309 PMCID: PMC6698665 DOI: 10.1093/nar/gkz466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 12/20/2022] Open
Abstract
Affinity maturation of the humoral immune response depends on somatic hypermutation (SHM) of immunoglobulin (Ig) genes, which is initiated by targeted lesion introduction by activation-induced deaminase (AID), followed by error-prone DNA repair. Stringent regulation of this process is essential to prevent genetic instability, but no negative feedback control has been identified to date. Here we show that poly(ADP-ribose) polymerase-1 (PARP-1) is a key factor restricting AID activity during somatic hypermutation. Poly(ADP-ribose) (PAR) chains formed at DNA breaks trigger AID-PAR association, thus preventing excessive DNA damage induction at sites of AID action. Accordingly, AID activity and somatic hypermutation at the Ig variable region is decreased by PARP-1 activity. In addition, PARP-1 regulates DNA lesion processing by affecting strand biased A:T mutagenesis. Our study establishes a novel function of the ancestral genome maintenance factor PARP-1 as a critical local feedback regulator of both AID activity and DNA repair during Ig gene diversification.
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Affiliation(s)
- Sandra Tepper
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany
| | - Oliver Mortusewicz
- Department of Biology II and Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany.,Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, S-171 76 Stockholm, Sweden
| | - Ewelina Członka
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany
| | - Amanda Bello
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany
| | - Angelika Schmidt
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany
| | - Julia Jeschke
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany
| | - Arthur Fischbach
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Ines Pfeil
- Institute of Clinical Molecular Biology, Helmholtz Center Munich, German Research Center for Environmental Health, 81377 Munich, Germany
| | - Svend K Petersen-Mahrt
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Milano, Italy
| | - Aswin Mangerich
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Thomas Helleday
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, S-171 76 Stockholm, Sweden
| | - Heinrich Leonhardt
- Department of Biology II and Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Berit Jungnickel
- Department of Cell Biology, Institute of Biochemistry and Biophysics, School of Biology and Pharmacy, Friedrich Schiller University, 07745 Jena, Germany.,Department of Biology, University of Konstanz, 78457 Konstanz, Germany
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13
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Kavoosi S, Sudhamalla B, Dey D, Shriver K, Arora S, Sappa S, Islam K. Site- and degree-specific C-H oxidation on 5-methylcytosine homologues for probing active DNA demethylation. Chem Sci 2019; 10:10550-10555. [PMID: 32055378 PMCID: PMC6988753 DOI: 10.1039/c9sc02629k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/28/2019] [Indexed: 12/14/2022] Open
Abstract
Activity of TET, AID and TDG enzymes in the DNA demethylation pathway was controlled using stereoelectronically constrained 5-methylcytosine homologues to generate conditionally stable DNA modification.
Ten-eleven translocation (TET) enzymes oxidize C–H bonds in 5-methylcytosine (5mC) to hydroxyl (5hmC), formyl (5fC) and carboxyl (5caC) intermediates en route to DNA demethylation. It has remained a challenge to study the function of a single oxidized product. We investigate whether alkyl groups other than methyl could be oxidized by TET proteins to generate a specific intermediate. We report here that TET2 oxidizes 5-ethylcytosine (5eC) only to 5-hydroxyethylcytosine (5heC). In biochemical assays, 5heC acts as a docking site for proteins implicated in transcription, imbuing this modification with potential gene regulatory activity. We observe that 5heC is resistant to downstream wild type hydrolases, but not to the engineered enzymes, thus establishing a unique tool to conditionally alter the stability of 5heC on DNA. Furthermore, we devised a chemical approach for orthogonal labeling of 5heC. Our work offers a platform for synthesis of novel 5-alkylcytosines, provides an approach to ‘tame’ TET activity, and identifies 5heC as an unnatural modification with a potential to control chromatin-dependent processes.
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Affiliation(s)
- Sam Kavoosi
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Babu Sudhamalla
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Debasis Dey
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Kirsten Shriver
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Simran Arora
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Sushma Sappa
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
| | - Kabirul Islam
- Department of Chemistry , University of Pittsburgh , Pennsylvania 15260 , USA .
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14
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Schoeler K, Aufschnaiter A, Messner S, Derudder E, Herzog S, Villunger A, Rajewsky K, Labi V. TET enzymes control antibody production and shape the mutational landscape in germinal centre B cells. FEBS J 2019; 286:3566-3581. [PMID: 31120187 PMCID: PMC6851767 DOI: 10.1111/febs.14934] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/09/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
Abstract
Upon activation by antigen, B cells form germinal centres where they clonally expand and introduce affinity-enhancing mutations into their B-cell receptor genes. Somatic mutagenesis and class switch recombination (CSR) in germinal centre B cells are initiated by the activation-induced cytidine deaminase (AID). Upon germinal centre exit, B cells differentiate into antibody-secreting plasma cells. Germinal centre maintenance and terminal fate choice require transcriptional reprogramming that associates with a substantial reconfiguration of DNA methylation patterns. Here we examine the role of ten-eleven-translocation (TET) proteins, enzymes that facilitate DNA demethylation and promote a permissive chromatin state by oxidizing 5-methylcytosine, in antibody-mediated immunity. Using a conditional gene ablation strategy, we show that TET2 and TET3 guide the transition of germinal centre B cells to antibody-secreting plasma cells. Optimal AID expression requires TET function, and TET2 and TET3 double-deficient germinal centre B cells show defects in CSR. However, TET2/TET3 double-deficiency does not prevent the generation and selection of high-affinity germinal centre B cells. Rather, combined TET2 and TET3 loss-of-function in germinal centre B cells favours C-to-T and G-to-A transition mutagenesis, a finding that may be of significance for understanding the aetiology of B-cell lymphomas evolving in conditions of reduced TET function.
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Affiliation(s)
- Katia Schoeler
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria
| | - Andreas Aufschnaiter
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria
| | - Simon Messner
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria
| | - Emmanuel Derudder
- Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Sebastian Herzog
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria
| | - Andreas Villunger
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Klaus Rajewsky
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin-Buch, Germany
| | - Verena Labi
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Austria
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15
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018. [DOI: https://doi.org/10.1155/2018/8764384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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16
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Bayraktar G, Kreutz MR. The Role of Activity-Dependent DNA Demethylation in the Adult Brain and in Neurological Disorders. Front Mol Neurosci 2018; 11:169. [PMID: 29875631 PMCID: PMC5975432 DOI: 10.3389/fnmol.2018.00169] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/04/2018] [Indexed: 01/11/2023] Open
Abstract
Over the last decade, an increasing number of reports underscored the importance of epigenetic regulations in brain plasticity. Epigenetic elements such as readers, writers and erasers recognize, establish, and remove the epigenetic tags in nucleosomes, respectively. One such regulation concerns DNA-methylation and demethylation, which are highly dynamic and activity-dependent processes even in the adult neurons. It is nowadays widely believed that external stimuli control the methylation marks on the DNA and that such processes serve transcriptional regulation in neurons. In this mini-review, we cover the current knowledge on the regulatory mechanisms controlling in particular DNA demethylation as well as the possible functional consequences in health and disease.
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Affiliation(s)
- Gonca Bayraktar
- RG Neuroplasticity, Leibniz Institute for Neurobiology Magdeburg, Germany
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz Institute for Neurobiology Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf Hamburg, Germany
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17
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Zhu Q, Stöger R, Alberio R. A Lexicon of DNA Modifications: Their Roles in Embryo Development and the Germline. Front Cell Dev Biol 2018; 6:24. [PMID: 29637072 PMCID: PMC5880922 DOI: 10.3389/fcell.2018.00024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/27/2018] [Indexed: 12/12/2022] Open
Abstract
5-methylcytosine (5mC) on CpG dinucleotides has been viewed as the major epigenetic modification in eukaryotes for a long time. Apart from 5mC, additional DNA modifications have been discovered in eukaryotic genomes. Many of these modifications are thought to be solely associated with DNA damage. However, growing evidence indicates that some base modifications, namely 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), 5-carboxylcytosine (5caC), and N6-methadenine (6mA), may be of biological relevance, particularly during early stages of embryo development. Although abundance of these DNA modifications in eukaryotic genomes can be low, there are suggestions that they cooperate with other epigenetic markers to affect DNA-protein interactions, gene expression, defense of genome stability and epigenetic inheritance. Little is still known about their distribution in different tissues and their functions during key stages of the animal lifecycle. This review discusses current knowledge and future perspectives of these novel DNA modifications in the mammalian genome with a focus on their dynamic distribution during early embryonic development and their potential function in epigenetic inheritance through the germ line.
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Affiliation(s)
- Qifan Zhu
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Reinhard Stöger
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Ramiro Alberio
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
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18
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19
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Carell T, Kurz MQ, Müller M, Rossa M, Spada F. Non-canonical Bases in the Genome: The Regulatory Information Layer in DNA. Angew Chem Int Ed Engl 2018; 57:4296-4312. [DOI: 10.1002/anie.201708228] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Thomas Carell
- Center for Integrated Protein Science; Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 Munich Germany
| | - Matthias Q. Kurz
- Center for Integrated Protein Science; Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 Munich Germany
| | - Markus Müller
- Center for Integrated Protein Science; Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 Munich Germany
| | - Martin Rossa
- Center for Integrated Protein Science; Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 Munich Germany
| | - Fabio Spada
- Center for Integrated Protein Science; Department of Chemistry; Ludwig-Maximilians-Universität München; Butenandtstrasse 5-13 81377 Munich Germany
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20
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Sheppard EC, Morrish RB, Dillon MJ, Leyland R, Chahwan R. Epigenomic Modifications Mediating Antibody Maturation. Front Immunol 2018. [PMID: 29535729 PMCID: PMC5834911 DOI: 10.3389/fimmu.2018.00355] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epigenetic modifications, such as histone modifications, DNA methylation status, and non-coding RNAs (ncRNA), all contribute to antibody maturation during somatic hypermutation (SHM) and class-switch recombination (CSR). Histone modifications alter the chromatin landscape and, together with DNA primary and tertiary structures, they help recruit Activation-Induced Cytidine Deaminase (AID) to the immunoglobulin (Ig) locus. AID is a potent DNA mutator, which catalyzes cytosine-to-uracil deamination on single-stranded DNA to create U:G mismatches. It has been shown that alternate chromatin modifications, in concert with ncRNAs and potentially DNA methylation, regulate AID recruitment and stabilize DNA repair factors. We, hereby, assess the combination of these distinct modifications and discuss how they contribute to initiating differential DNA repair pathways at the Ig locus, which ultimately leads to enhanced antibody–antigen binding affinity (SHM) or antibody isotype switching (CSR). We will also highlight how misregulation of epigenomic regulation during DNA repair can compromise antibody development and lead to a number of immunological syndromes and cancer.
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Affiliation(s)
- Emily C Sheppard
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Michael J Dillon
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Richard Chahwan
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
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21
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018; 2018:8764384. [PMID: 30073137 PMCID: PMC6057397 DOI: 10.1155/2018/8764384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/05/2018] [Accepted: 06/14/2018] [Indexed: 02/05/2023] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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22
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Schutsky EK, Nabel CS, Davis A, DeNizio JE, Kohli RM. APOBEC3A efficiently deaminates methylated, but not TET-oxidized, cytosine bases in DNA. Nucleic Acids Res 2017; 45:7655-7665. [PMID: 28472485 PMCID: PMC5570014 DOI: 10.1093/nar/gkx345] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/18/2017] [Indexed: 12/21/2022] Open
Abstract
AID/APOBEC family enzymes are best known for deaminating cytosine bases to uracil in single-stranded DNA, with characteristic sequence preferences that can produce mutational signatures in targets such as retroviral and cancer cell genomes. These deaminases have also been proposed to function in DNA demethylation via deamination of either 5-methylcytosine (mC) or TET-oxidized mC bases (ox-mCs), which include 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine. One specific family member, APOBEC3A (A3A), has been shown to readily deaminate mC, raising the prospect of broader activity on ox-mCs. To investigate this claim, we developed a novel assay that allows for parallel profiling of activity on all modified cytosines. Our steady-state kinetic analysis reveals that A3A discriminates against all ox-mCs by >3700-fold, arguing that ox-mC deamination does not contribute substantially to demethylation. A3A is, by contrast, highly proficient at C/mC deamination. Under conditions of excess enzyme, C/mC bases can be deaminated to completion in long DNA segments, regardless of sequence context. Interestingly, under limiting A3A, the sequence preferences observed with targeting unmodified cytosine are further exaggerated when deaminating mC. Our study informs how methylation, oxidation, and deamination can interplay in the genome and suggests A3A's potential utility as a biotechnological tool to discriminate between cytosine modification states.
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Affiliation(s)
- Emily K. Schutsky
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher S. Nabel
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amy K. F. Davis
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jamie E. DeNizio
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rahul M. Kohli
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
- To whom correspondence should be addressed. Tel: +1 215 573 7523; Fax: +1 215 348 5111;
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23
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Yin X, Xu Y. Structure and Function of TET Enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 945:275-302. [PMID: 27826843 DOI: 10.1007/978-3-319-43624-1_12] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mammalian DNA methylation mainly occurs at the carbon-C5 position of cytosine (5mC). TET enzymes were discovered to successively oxidize 5mC to 5-hydromethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). TET enzymes and oxidized 5mC derivatives play important roles in various biological and pathological processes, including regulation of DNA demethylation, gene transcription, embryonic development, and oncogenesis. In this chapter, we will discuss the discovery of TET-mediated 5mC oxidation and the structure, function, and regulation of TET enzymes.
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Affiliation(s)
- Xiaotong Yin
- Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.
- Key Laboratory of Molecular Medicine, Ministry of Education, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, 200433, China.
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24
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Budzko L, Jackowiak P, Kamel K, Sarzynska J, Bujnicki JM, Figlerowicz M. Mutations in human AID differentially affect its ability to deaminate cytidine and 5-methylcytidine in ssDNA substrates in vitro. Sci Rep 2017. [PMID: 28634398 PMCID: PMC5478644 DOI: 10.1038/s41598-017-03936-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) is known for its established role in antibody production. AID induces the diversification of antibodies by deaminating deoxycytidine (C) within immunoglobulin genes. The capacity of AID to deaminate 5-methyldeoxycytidine (5 mC) and/or 5-hydroxymethyldeoxycytidine (5 hmC), and consequently AID involvement in active DNA demethylation, is not fully resolved. For instance, structural determinants of AID activity on different substrates remain to be identified. To better understand the latter issue, we tested how mutations in human AID (hAID) influence its ability to deaminate C, 5 mC, and 5 hmC in vitro. We showed that each of the selected mutations differentially affects hAID’s ability to deaminate C and 5 mC. At the same time, we did not observe hAID activity on 5 hmC. Surprisingly, we found that the N51A hAID mutant, with no detectable activity on C, efficiently deaminated 5 mC, which may suggest different requirements for C and 5 mC deamination. Homology modeling and molecular dynamics simulations revealed that the pattern of enzyme-substrate recognition is one of the important factors determining enzyme activity on C and 5 mC. Consequently, we have proposed mechanisms that explain why wild type hAID more efficiently deaminates C than 5 mC in vitro and why 5 hmC is not deaminated.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Karol Kamel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Joanna Sarzynska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, 02-109, Warsaw, Poland.,Laboratory of Bioinformatics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614, Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland. .,Institute of Computing Science, Poznan University of Technology, Piotrowo 3A, 60-965, Poznan, Poland.
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25
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Abstract
DNA methylation plays important roles in development and disease. Yet, only recently has the dynamic nature of this epigenetic mark via oxidation and DNA repair-mediated demethylation been recognized. A major conceptual challenge to the model that DNA methylation is reversible is the risk of genomic instability, which may come with widespread DNA repair activity. Here, we focus on recent advances in mechanisms of TET-TDG mediated demethylation and cellular strategies that avoid genomic instability. We highlight the recently discovered involvement of NEIL DNA glycosylases, which cooperate with TDG in oxidative demethylation to accelerate substrate turnover and promote the organized handover of harmful repair intermediates to maintain genome stability.
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Affiliation(s)
| | - Christof Niehrs
- Institute of Molecular Biology (IMB), Mainz, Germany.,Division of Molecular Embryology, German Cancer Research Center-Zentrum für Molekulare Biologie der Universität Heidelberg (DKFZ-ZMBH) Alliance, Heidelberg, Germany
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26
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Cimmino L, Aifantis I. Alternative roles for oxidized mCs and TETs. Curr Opin Genet Dev 2016; 42:1-7. [PMID: 27939598 DOI: 10.1016/j.gde.2016.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 11/15/2016] [Indexed: 01/09/2023]
Abstract
Ten-eleven-translocation (TET) proteins oxidize 5-methylcytosine (5mC) to form stable or transient modifications (oxi-mCs) in the mammalian genome. Genome-wide mapping and protein interaction studies have shown that 5mC and oxi-mCs have unique distribution patterns and alternative roles in gene expression. In addition, oxi-mCs may interact with specific chromatin regulators, transcription factors and DNA repair proteins to maintain genomic integrity or alter DNA replication and transcriptional elongation rates. In this review we will discuss recent advances in our understanding of how TETs and 5hmC exert their epigenetic function as tumor suppressors by playing alternative roles in transcriptional regulation and genomic stability.
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Affiliation(s)
- Luisa Cimmino
- Department of Pathology, NYU School of Medicine, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
| | - Iannis Aifantis
- Department of Pathology, NYU School of Medicine, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY 10016, USA
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27
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Bochtler M, Kolano A, Xu GL. DNA demethylation pathways: Additional players and regulators. Bioessays 2016; 39:1-13. [PMID: 27859411 DOI: 10.1002/bies.201600178] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
DNA demethylation can occur passively by "dilution" of methylation marks by DNA replication, or actively and independently of DNA replication. Direct conversion of 5-methylcytosine (5mC) to cytosine (C), as originally proposed, does not occur. Instead, active DNA methylation involves oxidation of the methylated base by ten-eleven translocations (TETs), or deamination of the methylated or a nearby base by activation induced deaminase (AID). The modified nucleotide, possibly together with surrounding nucleotides, is then replaced by the BER pathway. Recent data clarify the roles and the regulation of well-known enzymes in this process. They identify base excision repair (BER) glycosylases that may cooperate with or replace thymine DNA glycosylase (TDG) in the base excision step, and suggest possible involvement of DNA damage repair pathways other than BER in active DNA demethylation. Here, we review these new developments.
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Affiliation(s)
- Matthias Bochtler
- International Institute of Molecular and Cell Biology, Warsaw, Poland.,Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Kolano
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Guo-Liang Xu
- Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
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Abstract
The AID/APOBEC family enzymes convert cytosines in single-stranded DNA to uracils, causing base substitutions and strand breaks. They are induced by cytokines produced during the body's inflammatory response to infections, and they help combat infections through diverse mechanisms. AID is essential for the maturation of antibodies and causes mutations and deletions in antibody genes through somatic hypermutation (SHM) and class-switch recombination (CSR) processes. One member of the APOBEC family, APOBEC1, edits mRNA for a protein involved in lipid transport. Members of the APOBEC3 subfamily in humans (APOBEC3A, APOBEC3B, APOBEC3C, APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H) inhibit infections of viruses such as HIV-1, HBV, and HCV, and retrotransposition of endogenous retroelements through mutagenic and nonmutagenic mechanisms. There is emerging consensus that these enzymes can cause mutations in the cellular genome at replication forks or within transcription bubbles depending on the physiological state of the cell and the phase of the cell cycle during which they are expressed. We describe here the state of knowledge about the structures of these enzymes, regulation of their expression, and both the advantageous and deleterious consequences of their expression, including carcinogenesis. We highlight similarities among them and present a holistic view of their regulation and function.
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Affiliation(s)
- Sachini U Siriwardena
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Kang Chen
- Department of Obstetrics and Gynecology, Wayne State University , Detroit, Michigan 48201, United States
- Mucosal Immunology Studies Team, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
- Department of Immunology and Microbiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| | - Ashok S Bhagwat
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
- Department of Immunology and Microbiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
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29
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Drohat AC, Coey CT. Role of Base Excision "Repair" Enzymes in Erasing Epigenetic Marks from DNA. Chem Rev 2016; 116:12711-12729. [PMID: 27501078 DOI: 10.1021/acs.chemrev.6b00191] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Base excision repair (BER) is one of several DNA repair pathways found in all three domains of life. BER counters the mutagenic and cytotoxic effects of damage that occurs continuously to the nitrogenous bases in DNA, and its critical role in maintaining genomic integrity is well established. However, BER also performs essential functions in processes other than DNA repair, where it acts on naturally modified bases in DNA. A prominent example is the central role of BER in mediating active DNA demethylation, a multistep process that erases the epigenetic mark 5-methylcytosine (5mC), and derivatives thereof, converting them back to cytosine. Herein, we review recent advances in the understanding of how BER mediates this critical component of epigenetic regulation in plants and animals.
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Affiliation(s)
- Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Christopher T Coey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
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30
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Mahfoudhi E, Talhaoui I, Cabagnols X, Della Valle V, Secardin L, Rameau P, Bernard OA, Ishchenko AA, Abbes S, Vainchenker W, Saparbaev M, Plo I. TET2-mediated 5-hydroxymethylcytosine induces genetic instability and mutagenesis. DNA Repair (Amst) 2016; 43:78-88. [DOI: 10.1016/j.dnarep.2016.05.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/28/2016] [Accepted: 05/23/2016] [Indexed: 02/04/2023]
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31
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Tomkova M, McClellan M, Kriaucionis S, Schuster-Boeckler B. 5-hydroxymethylcytosine marks regions with reduced mutation frequency in human DNA. eLife 2016; 5. [PMID: 27183007 PMCID: PMC4931910 DOI: 10.7554/elife.17082] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022] Open
Abstract
CpG dinucleotides are the main mutational hot-spot in most cancers. The characteristic elevated C>T mutation rate in CpG sites has been related to 5-methylcytosine (5mC), an epigenetically modified base which resides in CpGs and plays a role in transcription silencing. In brain nearly a third of 5mCs have recently been found to exist in the form of 5-hydroxymethylcytosine (5hmC), yet the effect of 5hmC on mutational processes is still poorly understood. Here we show that 5hmC is associated with an up to 53% decrease in the frequency of C>T mutations in a CpG context compared to 5mC. Tissue specific 5hmC patterns in brain, kidney and blood correlate with lower regional CpG>T mutation frequency in cancers originating in the respective tissues. Together our data reveal global and opposing effects of the two most common cytosine modifications on the frequency of cancer causing somatic mutations in different cell types.
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Affiliation(s)
- Marketa Tomkova
- Ludwig Cancer Research Oxford, University of Oxford, Oxford, United Kingdom
| | - Michael McClellan
- Ludwig Cancer Research Oxford, University of Oxford, Oxford, United Kingdom
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32
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Schuermann D, Weber AR, Schär P. Active DNA demethylation by DNA repair: Facts and uncertainties. DNA Repair (Amst) 2016; 44:92-102. [PMID: 27247237 DOI: 10.1016/j.dnarep.2016.05.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Pathways that control and modulate DNA methylation patterning in mammalian cells were poorly understood for a long time, although their importance in establishing and maintaining cell type-specific gene expression was well recognized. The discovery of proteins capable of converting 5-methylcytosine (5mC) to putative substrates for DNA repair introduced a novel and exciting conceptual framework for the investigation and ultimate discovery of molecular mechanisms of DNA demethylation. Against the prevailing notion that DNA methylation is a static epigenetic mark, it turned out to be dynamic and distinct mechanisms appear to have evolved to effect global and locus-specific DNA demethylation. There is compelling evidence that DNA repair, in particular base excision repair, contributes significantly to the turnover of 5mC in cells. By actively demethylating DNA, DNA repair supports the developmental establishment as well as the maintenance of DNA methylation landscapes and gene expression patterns. Yet, while the biochemical pathways are relatively well-established and reviewed, the biological context, function and regulation of DNA repair-mediated active DNA demethylation remains uncertain. In this review, we will thus summarize and critically discuss the evidence that associates active DNA demethylation by DNA repair with specific functional contexts including the DNA methylation erasure in the early embryo, the control of pluripotency and cellular differentiation, the maintenance of cell identity, and the nuclear reprogramming.
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Affiliation(s)
- David Schuermann
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland
| | - Alain R Weber
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland
| | - Primo Schär
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland.
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33
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Knisbacher BA, Gerber D, Levanon EY. DNA Editing by APOBECs: A Genomic Preserver and Transformer. Trends Genet 2016; 32:16-28. [PMID: 26608778 DOI: 10.1016/j.tig.2015.10.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 10/18/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
Information warfare is not limited to the cyber world because it is waged within our cells as well. The unique AID (activation-induced cytidine deaminase)/APOBEC (apolipoprotein B mRNA editing enzyme, catalytic polypeptide) family comprises proteins that alter DNA sequences by converting deoxycytidines to deoxyuridines through deamination. This C-to-U DNA editing enables them to inhibit parasitic viruses and retrotransposons by disrupting their genomic content. In addition to attacking genomic invaders, APOBECs can target their host genome, which can be beneficial by initiating processes that create antibody diversity needed for the immune system or by accelerating the rate of evolution. AID can also alter gene regulation by removing epigenetic modifications from genomic DNA. However, when uncontrolled, these powerful agents of change can threaten genome stability and eventually lead to cancer.
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Affiliation(s)
- Binyamin A Knisbacher
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900 Israel
| | - Doron Gerber
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900 Israel
| | - Erez Y Levanon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 52900 Israel.
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34
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Bellacosa A, Drohat AC. Role of base excision repair in maintaining the genetic and epigenetic integrity of CpG sites. DNA Repair (Amst) 2015; 32:33-42. [PMID: 26021671 DOI: 10.1016/j.dnarep.2015.04.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytosine methylation at CpG dinucleotides is a central component of epigenetic regulation in vertebrates, and the base excision repair (BER) pathway is important for maintaining both the genetic stability and the methylation status of CpG sites. This perspective focuses on two enzymes that are of particular importance for the genetic and epigenetic integrity of CpG sites, methyl binding domain 4 (MBD4) and thymine DNA glycosylase (TDG). We discuss their capacity for countering C to T mutations at CpG sites, by initiating base excision repair of G · T mismatches generated by deamination of 5-methylcytosine (5mC). We also consider their role in active DNA demethylation, including pathways that are initiated by oxidation and/or deamination of 5mC.
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Affiliation(s)
- Alfonso Bellacosa
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, United States.
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD 21201, United States.
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35
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Lu X, Zhao BS, He C. TET family proteins: oxidation activity, interacting molecules, and functions in diseases. Chem Rev 2015; 115:2225-39. [PMID: 25675246 DOI: 10.1021/cr500470n] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Xingyu Lu
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Boxuan Simen Zhao
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Chuan He
- †Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.,‡Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
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36
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Ramiro AR, Barreto VM. Activation-induced cytidine deaminase and active DNA demethylation. Trends Biochem Sci 2015; 40:172-81. [PMID: 25661247 DOI: 10.1016/j.tibs.2015.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/11/2015] [Accepted: 01/12/2015] [Indexed: 12/22/2022]
Abstract
The regulation of demethylation in vertebrates has begun to be elucidated in the past decade. However, a possible involvement of activation-induced cytidine deaminase (AID) in this process remains uncertain. We survey the data supporting or casting doubt on such a role, and propose that there is no strong evidence for an involvement of AID in genome-wide active demethylation processes. Conversely, we present evidence that favors AID involvement in gene-specific demethylation events underlying cell differentiation.
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Affiliation(s)
- Almudena R Ramiro
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Calle de Melchor Fernandez Almagro 3, 28029 Madrid, Spain
| | - Vasco M Barreto
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras, Portugal.
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37
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Scourzic L, Mouly E, Bernard OA. TET proteins and the control of cytosine demethylation in cancer. Genome Med 2015; 7:9. [PMID: 25632305 PMCID: PMC4308928 DOI: 10.1186/s13073-015-0134-6] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The discovery that ten-eleven translocation (TET) proteins are α-ketoglutarate-dependent dioxygenases involved in the conversion of 5-methylcytosines (5-mC) to 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine and 5-carboxycytosine has revealed new pathways in the cytosine methylation and demethylation process. The description of inactivating mutations in TET2 suggests that cellular transformation is in part caused by the deregulation of this 5-mC conversion. The direct and indirect deregulation of methylation control through mutations in DNA methyltransferase and isocitrate dehydrogenase (IDH) genes, respectively, along with the importance of cytosine methylation in the control of normal and malignant cellular differentiation have provided a conceptual framework for understanding the early steps in cancer development. Here, we review recent advances in our understanding of the cytosine methylation cycle and its implication in cellular transformation, with an emphasis on TET enzymes and 5-hmC. Ongoing clinical trials targeting the activity of mutated IDH enzymes provide a proof of principle that DNA methylation is targetable, and will trigger further therapeutic applications aimed at controlling both early and late stages of cancer development.
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Affiliation(s)
- Laurianne Scourzic
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1170, équipe labellisée Ligue Contre le Cancer, 94805 Villejuif, France ; Institut Gustave Roussy, 94805 Villejuif, France ; University Paris 11 Sud, 91405 Orsay, France
| | - Enguerran Mouly
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1170, équipe labellisée Ligue Contre le Cancer, 94805 Villejuif, France ; Institut Gustave Roussy, 94805 Villejuif, France ; University Paris 11 Sud, 91405 Orsay, France
| | - Olivier A Bernard
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1170, équipe labellisée Ligue Contre le Cancer, 94805 Villejuif, France ; Institut Gustave Roussy, 94805 Villejuif, France ; University Paris 11 Sud, 91405 Orsay, France
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38
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Shimoda N, Hirose K, Kaneto R, Izawa T, Yokoi H, Hashimoto N, Kikuchi Y. No evidence for AID/MBD4-coupled DNA demethylation in zebrafish embryos. PLoS One 2014; 9:e114816. [PMID: 25536520 PMCID: PMC4275248 DOI: 10.1371/journal.pone.0114816] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 10/28/2014] [Indexed: 12/20/2022] Open
Abstract
The mechanisms responsible for active DNA demethylation remain elusive in Metazoa. A previous study that utilized zebrafish embryos provided a potent mechanism for active demethylation in which three proteins, AID, MBD4, and GADD45 are involved. We recently found age-dependent DNA hypomethylation in zebrafish, and it prompted us to examine if AID and MBD4 could be involved in the phenomenon. Unexpectedly, however, we found that most of the findings in the previous study were not reproducible. First, the injection of a methylated DNA fragment into zebrafish eggs did not affect either the methylation of genomic DNA, injected methylated DNA itself, or several loci tested or the expression level of aid, which has been shown to play a role in demethylation. Second, aberrant methylation was not observed at certain CpG islands following the injection of antisense morpholino oligonucleotides against aid and mbd4. Furthermore, we demonstrated that zebrafish MBD4 cDNA lacked a coding region for the methyl-CpG binding domain, which was assumed to be necessary for guidance to target regions. Taken together, we concluded that there is currently no evidence to support the proposed roles of AID and MBD4 in active demethylation in zebrafish embryos.
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Affiliation(s)
- Nobuyoshi Shimoda
- Department of Regenerative Medicine, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Obu, Aichi 474-8522, Japan
- * E-mail:
| | - Kentaro Hirose
- Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Reiya Kaneto
- Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Toshiaki Izawa
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Hayato Yokoi
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumi-Dori Amamiya-Machi, Aoba-Ku, Sendai 981-8555, Japan
| | - Naohiro Hashimoto
- Department of Regenerative Medicine, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Obu, Aichi 474-8522, Japan
| | - Yutaka Kikuchi
- Department of Biological Science, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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39
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Dominguez PM, Shaknovich R. Epigenetic function of activation-induced cytidine deaminase and its link to lymphomagenesis. Front Immunol 2014; 5:642. [PMID: 25566255 PMCID: PMC4270259 DOI: 10.3389/fimmu.2014.00642] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/02/2014] [Indexed: 01/16/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) is essential for somatic hypermutation and class switch recombination of immunoglobulin (Ig) genes during B cell maturation and immune response. Expression of AID is tightly regulated due to its mutagenic and recombinogenic potential, which is known to target not only Ig genes, but also non-Ig genes, contributing to lymphomagenesis. In recent years, a new epigenetic function of AID and its link to DNA demethylation came to light in several developmental systems. In this review, we summarize existing evidence linking deamination of unmodified and modified cytidine by AID to base-excision repair and mismatch repair machinery resulting in passive or active removal of DNA methylation mark, with the focus on B cell biology. We also discuss potential contribution of AID-dependent DNA hypomethylation to lymphomagenesis.
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Affiliation(s)
- Pilar M Dominguez
- Division of Hematology and Oncology, Weill Cornell Medical College , New York, NY , USA
| | - Rita Shaknovich
- Division of Hematology and Oncology, Weill Cornell Medical College , New York, NY , USA ; Department of Pathology and Laboratory Medicine, Weill Cornell Medical College , New York, NY , USA
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40
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Nakajima H, Kunimoto H. TET2 as an epigenetic master regulator for normal and malignant hematopoiesis. Cancer Sci 2014; 105:1093-9. [PMID: 25040794 PMCID: PMC4462392 DOI: 10.1111/cas.12484] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/03/2014] [Accepted: 07/05/2014] [Indexed: 12/16/2022] Open
Abstract
DNA methylation is one of the critical epigenetic modifications regulating various cellular processes such as differentiation or proliferation, and its dysregulation leads to disordered stem cell function or cellular transformation. The ten-eleven translocation (TET) gene family, initially found as a chromosomal translocation partner in leukemia, turned out to be a key enzyme for DNA demethylation. TET genes hydroxylate 5-methylcytosine to 5-hydroxymethylcytosine, which is then converted to unmodified cytosine through multiple mechanisms. Somatic mutations of the TET2 gene were reported in a variety of human hematological malignancies such as leukemia, myelodysplastic syndrome, and malignant lymphoma, suggesting a critical role for TET2 in hematopoiesis. The importance of the TET-mediated cytosine demethylation pathway is also underscored by a recurrent mutation of isocitrate dehydrogenase 1 (IDH1) and IDH2 in hematological malignancies, whose mutation inhibits TET function through a novel oncometabolite, 2-hydroxyglutarate. Studies using mouse models revealed that TET2 is critical for the function of hematopoietic stem cells, and disruption of TET2 results in the expansion of multipotent as well as myeloid progenitors, leading to the accumulation of premalignant clones. In addition to cytosine demethylation, TET proteins are involved in chromatin modifications and other cellular processes through the interaction with O-linked β-N-acetylglucosamine transferase. In summary, TET2 is a critical regulator for hematopoietic stem cell homeostasis whose functional impairment leads to hematological malignancies. Future studies will uncover the whole picture of epigenetic and signaling networks wired with TET2, which will help to develop ways to intervene in cellular pathways dysregulated by TET2 mutations.
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Affiliation(s)
- Hideaki Nakajima
- Division of Hematology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
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41
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Franchini DM, Petersen-Mahrt SK. AID and APOBEC deaminases: balancing DNA damage in epigenetics and immunity. Epigenomics 2014; 6:427-43. [DOI: 10.2217/epi.14.35] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
DNA mutations and genomic recombinations are the origin of oncogenesis, yet parts of developmental programs as well as immunity are intimately linked to, or even depend on, such DNA damages. Therefore, the balance between deleterious DNA damages and organismal survival utilizing DNA editing (modification and repair) is in continuous flux. The cytosine deaminases AID/APOBEC are a DNA editing family and actively participate in various biological processes. In conjunction with altered DNA repair, the mutagenic potential of the family allows for APOBEC3 proteins to restrict viral infection and transposons propagation, while AID can induce somatic hypermutation and class switch recombination in antibody genes. On the other hand, the synergy between effective DNA repair and the nonmutagenic potential of the DNA deaminases can induce local DNA demethylation to support epigenetic cellular identity. Here, we review the current state of knowledge on the mechanisms of action of the AID/APOBEC family in immunity and epigenetics.
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Affiliation(s)
- Don-Marc Franchini
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Svend K Petersen-Mahrt
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
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42
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Dell'Isola A, McLachlan MMW, Neuman BW, Al-Mullah HMN, Binks AWD, Elvidge W, Shankland K, Cobb AJA. Synthesis and antiviral properties of spirocyclic [1,2,3]-triazolooxazine nucleosides. Chemistry 2014; 20:11685-9. [PMID: 25082061 PMCID: PMC7162048 DOI: 10.1002/chem.201403560] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Indexed: 12/11/2022]
Abstract
An efficient synthesis of spirocyclic triazolooxazine nucleosides is described. This was achieved by the conversion of β‐d‐psicofuranose to the corresponding azido‐derivative, followed by alkylation of the primary alcohol with a range of propargyl bromides, obtained by Sonogashira chemistry. The products of these reactions underwent 1,3‐dipolar addition smoothly to generate the protected spirocyclic adducts. These were easily deprotected to give the corresponding ribose nucleosides. The library of compounds obtained was investigated for its antiviral activity using MHV (mouse hepatitis virus) as a model wherein derivative 3 f showed the most promising activity and tolerability.
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Affiliation(s)
- Antonio Dell'Isola
- School of Chemistry, Food and Pharmacy (SCFP), University of Reading, Whiteknights, Reading, Berks RG6 6AD (UK)
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43
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Processive DNA demethylation via DNA deaminase-induced lesion resolution. PLoS One 2014; 9:e97754. [PMID: 25025377 PMCID: PMC4098905 DOI: 10.1371/journal.pone.0097754] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/23/2014] [Indexed: 12/13/2022] Open
Abstract
Base modifications of cytosine are an important aspect of chromatin biology, as they can directly regulate gene expression, while DNA repair ensures that those modifications retain genome integrity. Here we characterize how cytosine DNA deaminase AID can initiate DNA demethylation. In vitro, AID initiated targeted DNA demethylation of methyl CpGs when in combination with DNA repair competent extracts. Mechanistically, this is achieved by inducing base alterations at or near methyl-cytosine, with the lesion being resolved either via single base substitution or a more efficient processive polymerase dependent repair. The biochemical findings are recapitulated in an in vivo transgenic targeting assay, and provide the genetic support of the molecular insight into DNA demethylation. This targeting approach supports the hypothesis that mCpG DNA demethylation can proceed via various pathways and mCpGs do not have to be targeted to be demethylated.
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44
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Pfaffeneder T, Spada F, Wagner M, Brandmayr C, Laube SK, Eisen D, Truss M, Steinbacher J, Hackner B, Kotljarova O, Schuermann D, Michalakis S, Kosmatchev O, Schiesser S, Steigenberger B, Raddaoui N, Kashiwazaki G, Müller U, Spruijt CG, Vermeulen M, Leonhardt H, Schär P, Müller M, Carell T. Tet oxidizes thymine to 5-hydroxymethyluracil in mouse embryonic stem cell DNA. Nat Chem Biol 2014; 10:574-81. [PMID: 24838012 DOI: 10.1038/nchembio.1532] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 04/17/2014] [Indexed: 12/25/2022]
Abstract
Ten eleven translocation (Tet) enzymes oxidize the epigenetically important DNA base 5-methylcytosine (mC) stepwise to 5-hydroxymethylcytosine (hmC), 5-formylcytosine and 5-carboxycytosine. It is currently unknown whether Tet-induced oxidation is limited to cytosine-derived nucleobases or whether other nucleobases are oxidized as well. We synthesized isotopologs of all major oxidized pyrimidine and purine bases and performed quantitative MS to show that Tet-induced oxidation is not limited to mC but that thymine is also a substrate that gives 5-hydroxymethyluracil (hmU) in mouse embryonic stem cells (mESCs). Using MS-based isotope tracing, we show that deamination of hmC does not contribute to the steady-state levels of hmU in mESCs. Protein pull-down experiments in combination with peptide tracing identifies hmU as a base that influences binding of chromatin remodeling proteins and transcription factors, suggesting that hmU has a specific function in stem cells besides triggering DNA repair.
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Affiliation(s)
- Toni Pfaffeneder
- 1] Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany. [2]
| | - Fabio Spada
- 1] Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany. [2]
| | - Mirko Wagner
- 1] Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany. [2]
| | - Caterina Brandmayr
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Silvia K Laube
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - David Eisen
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Matthias Truss
- Charité Universitätsklinikum, Otto-Heubner-Centrum für Kinder und Jugendmedizin, Klinik für Allgemeine Pädiatrie, Labor für Pädiatrische Molekularbiologie, Berlin, Germany
| | - Jessica Steinbacher
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Benjamin Hackner
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Olga Kotljarova
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - David Schuermann
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Stylianos Michalakis
- Center for Integrated Protein Science at the Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Olesea Kosmatchev
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Stefan Schiesser
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Barbara Steigenberger
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Nada Raddaoui
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Gengo Kashiwazaki
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Udo Müller
- Center for Integrated Protein Science at the Department of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Cornelia G Spruijt
- Department of Molecular Cancer Research, Cancer Genomics Netherlands, Utrecht, The Netherlands
| | - Michiel Vermeulen
- 1] Department of Molecular Cancer Research, Cancer Genomics Netherlands, Utrecht, The Netherlands. [2]
| | - Heinrich Leonhardt
- Center for Integrated Protein Science at the Department of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Primo Schär
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Markus Müller
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Thomas Carell
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany
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Jang H, Shin H, Eichman BF, Huh JH. Excision of 5-hydroxymethylcytosine by DEMETER family DNA glycosylases. Biochem Biophys Res Commun 2014; 446:1067-72. [PMID: 24661881 DOI: 10.1016/j.bbrc.2014.03.060] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 03/15/2014] [Indexed: 12/25/2022]
Abstract
In plants and animals, 5-methylcytosine (5mC) serves as an epigenetic mark to repress gene expression, playing critical roles for cellular differentiation and transposon silencing. Mammals also have 5-hydroxymethylcytosine (5hmC), resulting from hydroxylation of 5mC by TET family-enzymes. 5hmC is abundant in mouse Purkinje neurons and embryonic stem cells, and regarded as an important intermediate for active DNA demethylation in mammals. However, the presence of 5hmC in plants has not been clearly demonstrated. In Arabidopsis, the DEMETER (DME) family DNA glycosylases efficiently remove 5mC, which results in DNA demethylation and transcriptional activation of target genes. Here we show that DME and ROS1 have a significant 5hmC excision activity in vitro, although we detected no 5hmC in Arabidopsis, suggesting that it is very unlikely for plants to utilize 5hmC as a DNA demethylation intermediate. Our results indicate that both plants and animals have 5mC in common but DNA demethylation systems have independently evolved with distinct mechanisms.
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Affiliation(s)
- Hosung Jang
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea
| | - Hosub Shin
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Jin Hoe Huh
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea.
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46
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Franchini DM, Incorvaia E, Rangam G, Coker HA, Petersen-Mahrt SK. Simultaneous in vitro characterisation of DNA deaminase function and associated DNA repair pathways. PLoS One 2013; 8:e82097. [PMID: 24349193 PMCID: PMC3857227 DOI: 10.1371/journal.pone.0082097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/25/2013] [Indexed: 02/02/2023] Open
Abstract
During immunoglobulin (Ig) diversification, activation-induced deaminase (AID) initiates somatic hypermutation and class switch recombination by catalysing the conversion of cytosine to uracil. The synergy between AID and DNA repair pathways is fundamental for the introduction of mutations, however the molecular and biochemical mechanisms underlying this process are not fully elucidated. We describe a novel method to efficiently decipher the composition and activity of DNA repair pathways that are activated by AID-induced lesions. The in vitro resolution (IVR) assay combines AID based deamination and DNA repair activities from a cellular milieu in a single assay, thus avoiding synthetically created DNA-lesions or genetic-based readouts. Recombinant GAL4-AID fusion protein is targeted to a plasmid containing GAL4 binding sites, allowing for controlled cytosine deamination within a substrate plasmid. Subsequently, the Xenopus laevis egg extract provides a source of DNA repair proteins and functional repair pathways. Our results demonstrated that DNA repair pathways which are in vitro activated by AID-induced lesions are reminiscent of those found during AID-induced in vivo Ig diversification. The comparative ease of manipulation of this in vitro systems provides a new approach to dissect the complex DNA repair pathways acting on defined physiologically lesions, can be adapted to use with other DNA damaging proteins (e.g. APOBECs), and provide a means to develop and characterise pharmacological agents to inhibit these potentially oncogenic processes.
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Affiliation(s)
- Don-Marc Franchini
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Milano, Italy
- DNA Editing Lab, Clare Hall Laboratories, London Research Institute, South Mimms, United Kingdom
| | - Elisabetta Incorvaia
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Milano, Italy
| | - Gopinath Rangam
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Milano, Italy
- DNA Editing Lab, Clare Hall Laboratories, London Research Institute, South Mimms, United Kingdom
| | - Heather A. Coker
- DNA Editing Lab, Clare Hall Laboratories, London Research Institute, South Mimms, United Kingdom
| | - Svend K. Petersen-Mahrt
- DNA Editing in Immunity and Epigenetics, IFOM-Fondazione Instituto FIRC di Oncologia Molecolare, Milano, Italy
- DNA Editing Lab, Clare Hall Laboratories, London Research Institute, South Mimms, United Kingdom
- * E-mail:
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47
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Lambert LJ, Walker S, Feltham J, Lee HJ, Reik W, Houseley J. Etoposide induces nuclear re-localisation of AID. PLoS One 2013; 8:e82110. [PMID: 24324754 PMCID: PMC3852760 DOI: 10.1371/journal.pone.0082110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/19/2013] [Indexed: 12/02/2022] Open
Abstract
During B cell activation, the DNA lesions that initiate somatic hypermutation and class switch recombination are introduced by activation-induced cytidine deaminase (AID). AID is a highly mutagenic protein that is maintained in the cytoplasm at steady state, however AID is shuttled across the nuclear membrane and the protein transiently present in the nucleus appears sufficient for targeted alteration of immunoglobulin loci. AID has been implicated in epigenetic reprogramming in primordial germ cells and cell fusions and in induced pluripotent stem cells (iPS cells), however AID expression in non-B cells is very low. We hypothesised that epigenetic reprogramming would require a pathway that instigates prolonged nuclear residence of AID. Here we show that AID is completely re-localised to the nucleus during drug withdrawal following etoposide treatment, in the period in which double strand breaks (DSBs) are repaired. Re-localisation occurs 2-6 hours after etoposide treatment, and AID remains in the nucleus for 10 or more hours, during which time cells remain live and motile. Re-localisation is cell-cycle dependent and is only observed in G2. Analysis of DSB dynamics shows that AID is re-localised in response to etoposide treatment, however re-localisation occurs substantially after DSB formation and the levels of re-localisation do not correlate with γH2AX levels. We conclude that DSB formation initiates a slow-acting pathway which allows stable long-term nuclear localisation of AID, and that such a pathway may enable AID-induced DNA demethylation during epigenetic reprogramming.
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Affiliation(s)
- Laurens J. Lambert
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Simon Walker
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Jack Feltham
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Heather J. Lee
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Wolf Reik
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Jonathan Houseley
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
- * E-mail:
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48
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TET enzymes, TDG and the dynamics of DNA demethylation. Nature 2013; 502:472-9. [PMID: 24153300 DOI: 10.1038/nature12750] [Citation(s) in RCA: 1096] [Impact Index Per Article: 99.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/06/2013] [Indexed: 01/17/2023]
Abstract
DNA methylation has a profound impact on genome stability, transcription and development. Although enzymes that catalyse DNA methylation have been well characterized, those that are involved in methyl group removal have remained elusive, until recently. The transformative discovery that ten-eleven translocation (TET) family enzymes can oxidize 5-methylcytosine has greatly advanced our understanding of DNA demethylation. 5-Hydroxymethylcytosine is a key nexus in demethylation that can either be passively depleted through DNA replication or actively reverted to cytosine through iterative oxidation and thymine DNA glycosylase (TDG)-mediated base excision repair. Methylation, oxidation and repair now offer a model for a complete cycle of dynamic cytosine modification, with mounting evidence for its significance in the biological processes known to involve active demethylation.
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49
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Getting rid of DNA methylation. Trends Cell Biol 2013; 24:136-43. [PMID: 24119665 DOI: 10.1016/j.tcb.2013.09.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 11/22/2022]
Abstract
Methylation of cytosine within DNA is associated with transcriptional repression and genome surveillance. In plants and animals, conserved pathways exist to establish and maintain this epigenetic mark. Mechanisms underlining its removal are, however, diverse and controversial and can depend on DNA synthesis (passive) or be independent of it (active). Ten-eleven translocation (Tet)-mediated conversion of 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has recently been evoked as a possible mechanism in the initiation of active and passive DNA demethylation. This review discuses the recent progress in this exciting area.
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50
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TETonic shift: biological roles of TET proteins in DNA demethylation and transcription. Nat Rev Mol Cell Biol 2013; 14:341-56. [PMID: 23698584 DOI: 10.1038/nrm3589] [Citation(s) in RCA: 654] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In many organisms, the methylation of cytosine in DNA has a key role in silencing 'parasitic' DNA elements, regulating transcription and establishing cellular identity. The recent discovery that ten-eleven translocation (TET) proteins are 5-methylcytosine oxidases has provided several chemically plausible pathways for the reversal of DNA methylation, thus triggering a paradigm shift in our understanding of how changes in DNA methylation are coupled to cell differentiation, embryonic development and cancer.
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