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Pandya P, Vendetti FP, El-Ghoubaira J, Pathak S, Deppas JJ, Jones R, Columbus AV, Zhang Y, Ivanov D, Huang Z, MacDonald KM, Harding SM, Buj R, Aird KM, Beumer JH, Sobol RW, Bakkenist CJ. Deoxyuridine-rich cytoplasmic DNA antagonizes STING-dependent innate immune responses and sensitizes resistant tumors to anti-PD-L1 therapy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588079. [PMID: 38883769 PMCID: PMC11178004 DOI: 10.1101/2024.04.04.588079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
DNA damage and cytoplasmic DNA induce type-1 interferon (IFN-1) and potentiate responses to immune checkpoint inhibitors. Our prior work found that inhibitors of the DNA damage response kinase ATR (ATRi) induce IFN-1 and deoxyuridine (dU) incorporation by DNA polymerases, akin to antimetabolites. Whether and how dU incorporation is required for ATRi-induced IFN-1 signaling is not known. Here, we show that ATRi-dependent IFN-1 responses require uracil DNA glycosylase (UNG)-initiated base excision repair and STING. Quantitative analyses of nine distinct nucleosides reveals that ATRi induce dU incorporation more rapidly in UNG wild-type than knockout cells, and that induction of IFN-1 is associated with futile cycles of repair. While ATRi induce similar numbers of micronuclei in UNG wild-type and knockout cells, dU containing micronuclei and cytoplasmic DNA are increased in knockout cells. Surprisingly, DNA fragments containing dU block STING-dependent induction of IFN-1, MHC-1, and PD-L1. Furthermore, UNG knockout sensitizes cells to IFN-γ in vitro , and potentiates responses to anti-PD-L1 in resistant tumors in vivo . These data demonstrate an unexpected and specific role for dU-rich DNA in suppressing STING-dependent IFN-1 responses, and show that UNG-deficient tumors have a heightened response to immune checkpoint inhibitors. STATEMENT OF SIGNIFICANCE Antimetabolites disrupt nucleotide pools and increase dU incorporation by DNA polymerases. We show that unrepaired dU potentiates responses to checkpoint inhibitors in mouse models of cancer. Patients with low tumor UNG may respond to antimetabolites combined with checkpoint inhibitors, and patients with high tumor UNG may respond to UNG inhibitors combined with checkpoint inhibitors.
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Hayran AB, Liabakk NB, Aas PA, Kusnierczyk A, Vågbø CB, Sarno A, Iveland TS, Chawla K, Zahn A, Di Noia JM, Slupphaug G, Kavli B. RPA guides UNG to uracil in ssDNA to facilitate antibody class switching and repair of mutagenic uracil at the replication fork. Nucleic Acids Res 2024; 52:784-800. [PMID: 38000394 PMCID: PMC10810282 DOI: 10.1093/nar/gkad1115] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 10/27/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) interacts with replication protein A (RPA), the major ssDNA-binding protein, to promote deamination of cytosine to uracil in transcribed immunoglobulin (Ig) genes. Uracil-DNA glycosylase (UNG) acts in concert with AID during Ig diversification. In addition, UNG preserves genome integrity by base-excision repair (BER) in the overall genome. How UNG is regulated to support both mutagenic processing and error-free repair remains unknown. UNG is expressed as two isoforms, UNG1 and UNG2, which both contain an RPA-binding helix that facilitates uracil excision from RPA-coated ssDNA. However, the impact of this interaction in antibody diversification and genome maintenance has not been investigated. Here, we generated B-cell clones with targeted mutations in the UNG RPA-binding motif, and analysed class switch recombination (CSR), mutation frequency (5' Ig Sμ), and genomic uracil in clones representing seven Ung genotypes. We show that the UNG:RPA interaction plays a crucial role in both CSR and repair of AID-induced uracil at the Ig loci. By contrast, the interaction had no significant impact on total genomic uracil levels. Thus, RPA coordinates UNG during CSR and pre-replicative repair of mutagenic uracil in ssDNA but is not essential in post-replicative and canonical BER of uracil in dsDNA.
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Affiliation(s)
- Abdul B Hayran
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Nina B Liabakk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Per A Aas
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Anna Kusnierczyk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Cathrine B Vågbø
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Antonio Sarno
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Tobias S Iveland
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Cancer Clinic, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Konika Chawla
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- BioCore - Bioinformatics Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
- Département of Médicine, Université de Montréal H3C 3J7 Montréal, Québec, Canada
| | - Geir Slupphaug
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- PROMEC - Proteomics and Modomics Experimental Core Facility at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
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3
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Dolbec D, Lehoux M, de Beauville AA, Zahn A, Di Noia JM, Segura M. Unmutated but T cell dependent IgM antibodies targeting Streptococcus suis play an essential role in bacterial clearance. PLoS Pathog 2024; 20:e1011957. [PMID: 38241393 PMCID: PMC10829992 DOI: 10.1371/journal.ppat.1011957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/31/2024] [Accepted: 01/08/2024] [Indexed: 01/21/2024] Open
Abstract
Streptococcus suis serotype 2 is an important encapsulated bacterial swine pathogen and zoonotic agent for which no effective vaccine exists. The interaction with B cells and the humoral response against S. suis are poorly understood despite their likely relevance for a potential vaccine. We evaluated germinal center (GC) B cell kinetics, as well as the production and role of S. suis-specific antibodies following infections in a mouse model. We found that mice infected with S. suis developed GC that peaked 13-21 days post-infection. GC further increased and persisted upon periodic reinfection that mimics real life conditions in swine farms. Anti-S. suis IgM and several IgG subclasses were produced, but antibodies against the S. suis capsular polysaccharide (CPS) were largely IgM. Interestingly, depletion of total IgG from the wild-type mice sera had no effect on bacterial killing by opsonophagocytosis in vitro. Somatic hypermutation and isotype switching were dispensable for controlling the infection or anti-CPS IgM production. However, T cell-deficient (Tcrb-/-) mice were unable to control bacteremia, produce optimal anti-CPS IgM titers, or elicit antibodies with opsonophagocytic activity. SAP deficiency, which prevents GC formation but not extrafollicular B cell responses, ablated anti S. suis-IgG production but maintained IgM production and eliminated the infection. In contrast, B cell deficient mice were unable to control bacteremia. Collectively, our results indicate that the antibody response plays a large role in immunity against S. suis, with GC-independent but T cell-dependent germline IgM being the major effective antibody specificities. Our results further highlight the importance IgM, and potentially anti-CPS antibodies, in clearing S. suis infections and provide insight for future development of S. suis vaccines.
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Affiliation(s)
- Dominic Dolbec
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Mélanie Lehoux
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Alexis Asselin de Beauville
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montréal, Center for Immunity, Inflammation and Infectious Diseases, Quebec, Canada
| | - Javier Marcelo Di Noia
- Institut de Recherches Cliniques de Montréal, Center for Immunity, Inflammation and Infectious Diseases, Quebec, Canada
- Department of Medicine, Faculty of Sciences, University of Montreal, Montreal, Quebec, Canada
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
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4
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Kalyanasundaram S, Lefol Y, Gundersen S, Rognes T, Alsøe L, Nilsen HL, Hovig E, Sandve GK, Domanska D. hGSuite HyperBrowser: A web-based toolkit for hierarchical metadata-informed analysis of genomic tracks. PLoS One 2023; 18:e0286330. [PMID: 37467208 DOI: 10.1371/journal.pone.0286330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/15/2023] [Indexed: 07/21/2023] Open
Abstract
Many high-throughput sequencing datasets can be represented as objects with coordinates along a reference genome. Currently, biological investigations often involve a large number of such datasets, for example representing different cell types or epigenetic factors. Drawing overall conclusions from a large collection of results for individual datasets may be challenging and time-consuming. Meaningful interpretation often requires the results to be aggregated according to metadata that represents biological characteristics of interest. In this light, we here propose the hierarchical Genomic Suite HyperBrowser (hGSuite), an open-source extension to the GSuite HyperBrowser platform, which aims to provide a means for extracting key results from an aggregated collection of high-throughput DNA sequencing data. The hGSuite utilizes a metadata-informed data cube to calculate various statistics across the multiple dimensions of the datasets. With this work, we show that the hGSuite and its associated data cube methodology offers a quick and accessible way for exploratory analysis of large genomic datasets. The web-based toolkit named hGsuite Hyperbrowser is available at https://hyperbrowser.uio.no/hgsuite under a GPLv3 license.
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Affiliation(s)
- Sumana Kalyanasundaram
- Center for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Biomedical Informatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Yohan Lefol
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Microbiology, University Hospital, Oslo, Norway
| | - Sveinung Gundersen
- Center for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
- Biomedical Informatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Torbjørn Rognes
- Center for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
- Department of Microbiology, University Hospital, Oslo, Norway
- Biomedical Informatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Lene Alsøe
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Microbiology, University Hospital, Oslo, Norway
| | - Hilde Loge Nilsen
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Microbiology, University Hospital, Oslo, Norway
| | - Eivind Hovig
- Center for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Biomedical Informatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Geir Kjetil Sandve
- Center for Bioinformatics, Department of Informatics, University of Oslo, Oslo, Norway
- Biomedical Informatics, Department of Informatics, University of Oslo, Oslo, Norway
| | - Diana Domanska
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Pathology, University Hospital, Oslo, Norway
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5
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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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6
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Britan-Rosich Y, Ma J, Kotler E, Hassan F, Botvinnik A, Smith Y, Moshel O, Nasereddin A, Sharma G, Pikarsky E, Ross S, Kotler M. APOBEC3G protects the genome of human cultured cells and mice from radiation-induced damage. FEBS J 2023; 290:1822-1839. [PMID: 36325681 PMCID: PMC10079569 DOI: 10.1111/febs.16673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 09/14/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022]
Abstract
Cytosine deaminases AID/APOBEC proteins act as potent nucleic acid editors, playing important roles in innate and adaptive immunity. However, the mutagenic effects of some of these proteins compromise genomic integrity and may promote tumorigenesis. Here, we demonstrate that human APOBEC3G (A3G), in addition to its role in innate immunity, promotes repair of double-strand breaks (DSBs) in vitro and in vivo. Transgenic mice expressing A3G successfully survived lethal irradiation, whereas wild-type controls quickly succumbed to radiation syndrome. Mass spectrometric analyses identified the differential upregulation of a plethora of proteins involved in DSB repair pathways in A3G-expressing cells early following irradiation to facilitate repair. Importantly, we find that A3G not only accelerates DSB repair but also promotes deamination-dependent error-free rejoining. These findings have two implications: (a) strategies aimed at inhibiting A3G may improve the efficacy of genotoxic therapies used to cure malignant tumours; and (b) enhancing A3G activity may reduce acute radiation syndrome in individuals exposed to ionizing radiation.
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Affiliation(s)
- Yelena Britan-Rosich
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Jing Ma
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, USA
| | - Eran Kotler
- Department of Genetics, Stanford University School of Medicine, Ca, USA
| | - Faizan Hassan
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Alexander Botvinnik
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Yoav Smith
- Genomic Data Analysis, Hadassah Medical School, Hebrew University, Jerusalem, Israel
| | - Ofra Moshel
- Core Research Facility, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Abed Nasereddin
- Core Research Facility of the Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Gunjan Sharma
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Eli Pikarsky
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Susan Ross
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, USA
| | - Moshe Kotler
- Department of Pathology and Immunology, The Lautenberg Center for Immunology and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
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7
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Carracedo S, Lirussi L, Alsøe L, Segers F, Wang C, Bartosova Z, Bohov P, Tekin NB, Kong XY, Esbensen QY, Chen L, Wennerström A, Kroustallaki P, Ceolotto D, Tönjes A, Berge RK, Bruheim P, Wong G, Böttcher Y, Halvorsen B, Nilsen H. SMUG1 regulates fat homeostasis leading to a fatty liver phenotype in mice. DNA Repair (Amst) 2022; 120:103410. [DOI: 10.1016/j.dnarep.2022.103410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 08/08/2022] [Accepted: 10/01/2022] [Indexed: 11/25/2022]
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8
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Marsden CG, Das L, Nottoli TP, Kathe SD, Doublié S, Wallace SS, Sweasy JB. Mouse Embryonic Fibroblasts Isolated From Nthl1 D227Y Knockin Mice Exhibit Defective DNA Repair and Increased Genome Instability. DNA Repair (Amst) 2022; 109:103247. [PMID: 34826736 PMCID: PMC8787541 DOI: 10.1016/j.dnarep.2021.103247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 01/03/2023]
Abstract
Oxidative DNA damage as a result of normal cellular metabolism, inflammation, or exposure to exogenous DNA damaging agents if left unrepaired, can result in genomic instability, a precursor to cancer and other diseases. Nth-like DNA glycosylase 1 (NTHL1) is an evolutionarily conserved bifunctional DNA glycosylase that primarily removes oxidized pyrimidine lesions. NTHL1 D239Y is a germline variant identified in both heterozygous and homozygous state in the human population. Here, we have generated a knockin mouse model carrying Nthl1 D227Y (mouse homologue of D239Y) using CRISPR-cas9 genome editing technology and investigated the cellular effects of the variant in the heterozygous (Y/+) and homozygous (Y/Y) state using murine embryonic fibroblasts. We identified a significant increase in double stranded breaks, genomic instability, replication stress and impaired proliferation in both the Nthl1 D227Y heterozygous Y/+ and homozygous mutant Y/Y MEFs. Importantly, we identified that the presence of the D227Y variant interferes with repair by the WT protein, possibly by binding and shielding the lesions. The cellular phenotypes observed in D227Y mutant MEFs suggest that both the heterozygous and homozygous carriers of this NTHL1 germline mutation may be at increased risk for the development of DNA damage-associated diseases, including cancer.
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Affiliation(s)
- Carolyn G. Marsden
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405-0068
| | - Lipsa Das
- Present address: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, Tucson, AZ 85724-5024, USA
| | - Timothy P. Nottoli
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Scott D. Kathe
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405-0068
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405-0068
| | - Susan S. Wallace
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405-0068
| | - Joann B. Sweasy
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405-0068,Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510,Present address: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, Tucson, AZ 85724-5024, USA,Corresponding author contact information: Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, 1515 N Campbell Avenue, Tucson, AZ 85724-5024, USA,
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9
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A New Class of Uracil-DNA Glycosylase Inhibitors Active against Human and Vaccinia Virus Enzyme. Molecules 2021; 26:molecules26216668. [PMID: 34771075 PMCID: PMC8587785 DOI: 10.3390/molecules26216668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/24/2021] [Accepted: 10/30/2021] [Indexed: 11/17/2022] Open
Abstract
Uracil-DNA glycosylases are enzymes that excise uracil bases appearing in DNA as a result of cytosine deamination or accidental dUMP incorporation from the dUTP pool. The activity of Family 1 uracil-DNA glycosylase (UNG) activity limits the efficiency of antimetabolite drugs and is essential for virulence in some bacterial and viral infections. Thus, UNG is regarded as a promising target for antitumor, antiviral, antibacterial, and antiprotozoal drugs. Most UNG inhibitors presently developed are based on the uracil base linked to various substituents, yet new pharmacophores are wanted to target a wide range of UNGs. We have conducted virtual screening of a 1,027,767-ligand library and biochemically screened the best hits for the inhibitory activity against human and vaccinia virus UNG enzymes. Although even the best inhibitors had IC50 ≥ 100 μM, they were highly enriched in a common fragment, tetrahydro-2,4,6-trioxopyrimidinylidene (PyO3). In silico, PyO3 preferably docked into the enzyme's active site, and in kinetic experiments, the inhibition was better consistent with the competitive mechanism. The toxicity of two best inhibitors for human cells was independent of the presence of methotrexate, which is consistent with the hypothesis that dUMP in genomic DNA is less toxic for the cell than strand breaks arising from the massive removal of uracil. We conclude that PyO3 may be a novel pharmacophore with the potential for development into UNG-targeting agents.
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10
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Zhang M, Yang D, Gold B. Origins of nonsense mutations in human tumor suppressor genes. Mutat Res 2021; 823:111761. [PMID: 34461460 DOI: 10.1016/j.mrfmmm.2021.111761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/27/2020] [Accepted: 08/12/2021] [Indexed: 11/26/2022]
Abstract
Understanding the origins of mutations in tumor suppressor genes and oncogenes associated with cancers in different tissues is critical to the development of potential prevention strategies. Analysis of >10,000 nonsense mutations in 63 tumor suppressor genes based on the ratio of the number of nonsense mutations per codon type is reported for each gene. The ratio for C•G→T•A nonsense mutations at Arg CGA codons to the number of CGA codons in all cancers is 23 (3088 total nonsense mutations for 134 CGA codons in the 63 suppressor genes). The ratio for this codon, which is attributed to hydrolytic deamination of 5-methylcytosine at CpG sites based on the sequence context, is 6-fold higher than the next highest ratio that involves a C•G→T•A transition at Trp TGG codons. C•G→A•T transversions at Glu, Ser, Tyr, Gly and Cys codons account for 25 % of the total nonsense mutations but the mutation per codon ratio for these codons is 1.0. Analysis of the bases 5' of the mutated CGA codons in the 63 tumor suppressor genes in all cancers shows a preference of 5'-G > C ∼ T ∼ A, which is not indicative of a role for enzymatic deamination by deaminases. Overall C•G→T•A mutations account for 61 % of all of the nonsense mutations in the collection of tumor suppressor genes. It is demonstrated that the ratio of C•G→T•A deamination-associated nonsense mutations at CGA codons (hydrolytic deamination) to the number of frame shift insertion/deletion mutations (i.e., replication based) for 5 major tumor suppressors genes are very similar in 3 different tissues that undergo a wide range of stem cell divisions. Therefore, the frequency of deamination mutations parallels the number of stem cell replications. This may reflect the generation of more solvent accessible single-stranded DNA regions during polymerization that are kinetically more prone to deamination.
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Affiliation(s)
- Min Zhang
- Department of Pharmaceutical Sciences, University of Pittsburgh, Salk Hall, Pittsburgh, PA, 15261, United States
| | - Da Yang
- Department of Pharmaceutical Sciences, University of Pittsburgh, Salk Hall, Pittsburgh, PA, 15261, United States
| | - Barry Gold
- Department of Pharmaceutical Sciences, University of Pittsburgh, Salk Hall, Pittsburgh, PA, 15261, United States.
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11
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Genomic Uracil and Aberrant Profile of Demethylation Intermediates in Epigenetics and Hematologic Malignancies. Int J Mol Sci 2021; 22:ijms22084212. [PMID: 33921666 PMCID: PMC8073381 DOI: 10.3390/ijms22084212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/30/2021] [Accepted: 04/14/2021] [Indexed: 12/19/2022] Open
Abstract
DNA of all living cells undergoes continuous structural and chemical alterations resulting from fundamental cellular metabolic processes and reactivity of normal cellular metabolites and constituents. Examples include enzymatically oxidized bases, aberrantly methylated bases, and deaminated bases, the latter largely uracil from deaminated cytosine. In addition, the non-canonical DNA base uracil may result from misincorporated dUMP. Furthermore, uracil generated by deamination of cytosine in DNA is not always damage as it is also an intermediate in normal somatic hypermutation (SHM) and class shift recombination (CSR) at the Ig locus of B-cells in adaptive immunity. Many of the modifications alter base-pairing properties and may thus cause replicative and transcriptional mutagenesis. The best known and most studied epigenetic mark in DNA is 5-methylcytosine (5mC), generated by a methyltransferase that uses SAM as methyl donor, usually in CpG contexts. Oxidation products of 5mC are now thought to be intermediates in active demethylation as well as epigenetic marks in their own rights. The aim of this review is to describe the endogenous processes that surround the generation and removal of the most common types of DNA nucleobase modifications, namely, uracil and certain epigenetic modifications, together with their role in the development of hematological malignances. We also discuss what dictates whether the presence of an altered nucleobase is defined as damage or a natural modification.
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Perkins JL, Zhao L. The N-terminal domain of uracil-DNA glycosylase: Roles for disordered regions. DNA Repair (Amst) 2021; 101:103077. [PMID: 33640758 DOI: 10.1016/j.dnarep.2021.103077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 02/14/2021] [Indexed: 01/10/2023]
Abstract
The presence of uracil in DNA calls for rapid removal facilitated by the uracil-DNA glycosylase superfamily of enzymes, which initiates the base excision repair (BER) pathway. In humans, uracil excision is accomplished primarily by the human uracil-DNA glycosylase (hUNG) enzymes. In addition to BER, hUNG enzymes play a key role in somatic hypermutation to generate antibody diversity. hUNG has several isoforms, with hUNG1 and hUNG2 being the two major isoforms. Both isoforms contain disordered N-terminal domains, which are responsible for a wide range of functions, with minimal direct impact on catalytic efficiency. Subcellular localization of hUNG enzymes is directed by differing N-terminal sequences, with hUNG1 dedicated to mitochondria and hUNG2 dedicated to the nucleus. An alternative isoform of hUNG1 has also been identified to localize to the nucleus in mouse and human cell models. Furthermore, hUNG2 has been observed at replication forks performing both pre- and post-replicative uracil excision to maintain genomic integrity. Replication protein A (RPA) and proliferating cell nuclear antigen (PCNA) are responsible for recruitment to replication forks via protein-protein interactions with the N-terminus of hUNG2. These interactions, along with protein degradation, are regulated by various post-translational modifications within the N-terminal tail, which are primarily cell-cycle dependent. Finally, translocation on DNA is also mediated by interactions between the N-terminus and DNA, which is enhanced under molecular crowding conditions by preventing diffusion events and compacting tail residues. This review summarizes recent research supporting the emerging roles of the N-terminal domain of hUNG.
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Affiliation(s)
- Jacob L Perkins
- Department of Chemistry and Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, United States
| | - Linlin Zhao
- Department of Chemistry and Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, United States.
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Safavi S, Larouche A, Zahn A, Patenaude AM, Domanska D, Dionne K, Rognes T, Dingler F, Kang SK, Liu Y, Johnson N, Hébert J, Verdun RE, Rada CA, Vega F, Nilsen H, Di Noia JM. The uracil-DNA glycosylase UNG protects the fitness of normal and cancer B cells expressing AID. NAR Cancer 2021; 2:zcaa019. [PMID: 33554121 PMCID: PMC7848951 DOI: 10.1093/narcan/zcaa019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022] Open
Abstract
In B lymphocytes, the uracil N-glycosylase (UNG) excises genomic uracils made by activation-induced deaminase (AID), thus underpinning antibody gene diversification and oncogenic chromosomal translocations, but also initiating faithful DNA repair. Ung−/− mice develop B-cell lymphoma (BCL). However, since UNG has anti- and pro-oncogenic activities, its tumor suppressor relevance is unclear. Moreover, how the constant DNA damage and repair caused by the AID and UNG interplay affects B-cell fitness and thereby the dynamics of cell populations in vivo is unknown. Here, we show that UNG specifically protects the fitness of germinal center B cells, which express AID, and not of any other B-cell subset, coincident with AID-induced telomere damage activating p53-dependent checkpoints. Consistent with AID expression being detrimental in UNG-deficient B cells, Ung−/− mice develop BCL originating from activated B cells but lose AID expression in the established tumor. Accordingly, we find that UNG is rarely lost in human BCL. The fitness preservation activity of UNG contingent to AID expression was confirmed in a B-cell leukemia model. Hence, UNG, typically considered a tumor suppressor, acquires tumor-enabling activity in cancer cell populations that express AID by protecting cell fitness.
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Affiliation(s)
- Shiva Safavi
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Ariane Larouche
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Anne-Marie Patenaude
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Diana Domanska
- Department of Informatics, University of Oslo, PO Box 1080, Blindern, 0316 Oslo, Norway
| | - Kiersten Dionne
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Torbjørn Rognes
- Department of Informatics, University of Oslo, PO Box 1080, Blindern, 0316 Oslo, Norway
| | - Felix Dingler
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Seong-Kwi Kang
- ITR Laboratories Canada, Inc., 19601 Clark Graham Ave, Baie-D'Urfe, QC H9X 3T1, Canada
| | - Yan Liu
- Section for Clinical Molecular Biology, Akershus University Hospital, PO 1000, 1478 Lørenskog, Norway
| | - Nathalie Johnson
- Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada
| | - Josée Hébert
- Department of Medicine, Université de Montréal, C.P. 6128, Montreal, QC H3C 3J7, Canada
| | - Ramiro E Verdun
- Division of Hematology, Department of Medicine, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33136, USA
| | | | - Francisco Vega
- Division of Hematology, Department of Medicine, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33136, USA
| | - Hilde Nilsen
- Section for Clinical Molecular Biology, Akershus University Hospital, PO 1000, 1478 Lørenskog, Norway
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montréal, 110 Av des Pins Ouest, Montréal, QC H2W 1R7, Canada
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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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Kladova OA, Iakovlev DA, Groisman R, Ishchenko AA, Saparbaev MK, Fedorova OS, Kuznetsov NA. An Assay for the Activity of Base Excision Repair Enzymes in Cellular Extracts Using Fluorescent DNA Probes. BIOCHEMISTRY (MOSCOW) 2021; 85:480-489. [PMID: 32569555 DOI: 10.1134/s0006297920040082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Damaged DNA bases are removed by the base excision repair (BER) mechanism. This enzymatic process begins with the action of one of DNA glycosylases, which recognize damaged DNA bases and remove them by hydrolyzing N-glycosidic bonds with the formation of apurinic/apyrimidinic (AP) sites. Apurinic/apyrimidinic endonuclease 1 (APE1) hydrolyzes the phosphodiester bond on the 5'-side of the AP site with generation of the single-strand DNA break. A decrease in the functional activity of BER enzymes is associated with the increased risk of cardiovascular, neurodegenerative, and oncological diseases. In this work, we developed a fluorescence method for measuring the activity of key human DNA glycosylases and AP endonuclease in cell extracts. The efficacy of fluorescent DNA probes was tested using purified enzymes; the most efficient probes were tested in the enzymatic activity assays in the extracts of A549, MCF7, HeLa, WT-7, HEK293T, and HKC8 cells. The activity of enzymes responsible for the repair of AP sites and removal of uracil and 5,6-dihydrouracil residues was higher in cancer cell lines as compared to the normal HKC8 human kidney cell line.
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Affiliation(s)
- O A Kladova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - D A Iakovlev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - R Groisman
- Groupe "Réparation de l'AND", Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Université Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France.,Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France
| | - A A Ishchenko
- Groupe "Réparation de l'AND", Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Université Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France.,Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France
| | - M K Saparbaev
- Groupe "Réparation de l'AND", Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Université Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France.,Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France
| | - O S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia. .,Novosibirsk State University, Novosibirsk, 630090, Russia
| | - N A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia. .,Novosibirsk State University, Novosibirsk, 630090, Russia
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Delgado P, Álvarez-Prado ÁF, Marina-Zárate E, Sernandez IV, Mur SM, de la Barrera J, Sanchez-Cabo F, Cañamero M, de Molina A, Belver L, de Yébenes VG, Ramiro AR. Interplay between UNG and AID governs intratumoral heterogeneity in mature B cell lymphoma. PLoS Genet 2020; 16:e1008960. [PMID: 33362210 PMCID: PMC7790409 DOI: 10.1371/journal.pgen.1008960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/07/2021] [Accepted: 11/08/2020] [Indexed: 12/11/2022] Open
Abstract
Most B cell lymphomas originate from B cells that have germinal center (GC) experience and bear chromosome translocations and numerous point mutations. GC B cells remodel their immunoglobulin (Ig) genes by somatic hypermutation (SHM) and class switch recombination (CSR) in their Ig genes. Activation Induced Deaminase (AID) initiates CSR and SHM by generating U:G mismatches on Ig DNA that can then be processed by Uracyl-N-glycosylase (UNG). AID promotes collateral damage in the form of chromosome translocations and off-target SHM, however, the exact contribution of AID activity to lymphoma generation and progression is not completely understood. Here we show using a conditional knock-in strategy that AID supra-activity alone is not sufficient to generate B cell transformation. In contrast, in the absence of UNG, AID supra-expression increases SHM and promotes lymphoma. Whole exome sequencing revealed that AID heavily contributes to lymphoma SHM, promoting subclonal variability and a wider range of oncogenic variants. Thus, our data provide direct evidence that UNG is a brake to AID-induced intratumoral heterogeneity and evolution of B cell lymphoma.
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Affiliation(s)
- Pilar Delgado
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Ángel F. Álvarez-Prado
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Ester Marina-Zárate
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Isora V. Sernandez
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Sonia M. Mur
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Jorge de la Barrera
- Bioinformatics Unit. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Fátima Sanchez-Cabo
- Bioinformatics Unit. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | | | - Antonio de Molina
- Comparative Medicine Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Laura Belver
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Virginia G. de Yébenes
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Almudena R. Ramiro
- B Lymphocyte Biology Lab. Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
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17
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Bao Y, Tong L, Song B, Liu G, Zhu Q, Lu X, Zhang J, Lu YF, Wen H, Tian Y, Sun Y, Zhu WG. UNG2 deacetylation confers cancer cell resistance to hydrogen peroxide-induced cytotoxicity. Free Radic Biol Med 2020; 160:403-417. [PMID: 32649985 DOI: 10.1016/j.freeradbiomed.2020.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 05/29/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023]
Abstract
Cancer therapeutics produce reactive oxygen species (ROS) that damage the cancer genome and lead to cell death. However, cancer cells can resist ROS-induced cytotoxicity and survive. We show that nuclear-localized uracil-DNA N-glycosylase isoform 2 (UNG2) has a critical role in preventing ROS-induced DNA damage and enabling cancer-cell resistance. Under physiological conditions, UNG2 is targeted for rapid degradation via an interaction with the E3 ligase UHRF1. In response to ROS, however, UNG2 protein in cancer cells exhibits a remarkably extended half-life. Upon ROS exposure, UNG2 is deacetylated at lysine 78 by histone deacetylases, which prevents the UNG2-UHRF1 interaction. Accumulated UNG2 protein can thus excise the base damaged by ROS and enable the cell to survive these otherwise toxic conditions. Consequently, combining HDAC inhibitors (to permit UNG2 degradation) with genotoxic agents (to produce cytotoxic cellular levels of ROS) leads to a robust synergistic killing effect in cancer cells in vitro. Altogether, these data support the application of a novel approach to cancer treatment based on promoting UNG2 degradation by altering its acetylation status using an HDAC inhibitor.
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Affiliation(s)
- Yantao Bao
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China; International Cancer Center, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Lili Tong
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Boyan Song
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Ge Liu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Qian Zhu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Xiaopeng Lu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Jun Zhang
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Ya-Fei Lu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - He Wen
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Yuan Tian
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China
| | - Yujie Sun
- Department of Cell Biology, Nanjing Medical University, Nanjing, 211166, China
| | - Wei-Guo Zhu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, 518055, China; International Cancer Center, Shenzhen University School of Medicine, Shenzhen, 518055, China; Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China; Shenzhen Bay Laboratory, Shenzhen University School of Medicine, Shenzhen, 518055, China.
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18
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Eldin P, Péron S, Galashevskaya A, Denis-Lagache N, Cogné M, Slupphaug G, Briant L. Impact of HIV-1 Vpr manipulation of the DNA repair enzyme UNG2 on B lymphocyte class switch recombination. J Transl Med 2020; 18:310. [PMID: 32778120 PMCID: PMC7418440 DOI: 10.1186/s12967-020-02478-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 08/02/2020] [Indexed: 02/06/2023] Open
Abstract
Background HIV-1 Vpr encodes a 14 kDa protein that has been implicated in viral pathogenesis through modulation of several host cell functions. In addition to pro-apoptotic and cytostatic properties, Vpr can redirect cellular E3 ubiquitin ligases (such as DCAF1-Cul4A E3 ligase complex) to target many host proteins and interfere with their functions. Among them, Vpr binds the uracil DNA glycosylase UNG2, which controls genome uracilation, and induces its specific degradation leading to loss of uracil removal activity in infected cells. Considering the essential role of UNG2 in antibody diversification in B-cells, we evaluated the impact of Vpr on UNG2 fate in B lymphocytes and examined the functional consequences of UNG2 modulations on class switch recombination (CSR). Methods The impact of Vpr-induced UNG2 deregulation on CSR proficiency was evaluated by using virus-like particles able to deliver Vpr protein to target cells including the murine model CSR B cell line CH12F3 and mouse primary B-cells. Co-culture experiments were used to re-examine the ability of Vpr to be released by HIV-1 infected cells and to effectively accumulate in bystander B-cells. Vpr-mediated UNG2 modulations were monitored by following UNG2 protein abundance and uracil removal enzymatic activity. Results In this study we report the ability of Vpr to reduce immunoglobulin class switch recombination (CSR) in immortalized and primary mouse B-cells through the degradation of UNG2. We also emphasize that Vpr is released by producing cells and penetrates bystander B lymphocytes. Conclusions This work therefore opens up new perspectives to study alterations of the B-cell response by using Vpr as a specific CSR blocking tool. Moreover, our results raise the question of whether extracellular HIV-1 Vpr detected in some patients may manipulate the antibody diversification process that engineers an adapted response against pathogenic intruders and thereby contribute to the intrinsic B-cell humoral defect reported in infected patients.
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Affiliation(s)
- Patrick Eldin
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, UMR 9004, Université de Montpellier, 1919 Route de Mende, 34293, Montpellier Cedex 5, France.
| | - Sophie Péron
- Contrôle de la Réponse Immune B et des Lymphoproliférations (CBRIL), UMR CNRS 7276 INSERM 1262, Centre de Biologie et de Recherche en Santé (CBRS), Faculté de Limoges, 2 rue du Dr. Marcland, 87000, Limoges, France
| | - Anastasia Galashevskaya
- Proteomics and Modomics Experimental Core (PROMEC), Department of Cancer Research and Molecular Medicine, Laboratory Centre, Norwegian University of Science and Technology (NTNU), 5th Floor. Erling Skjalgssons gt. 1, 7491, Trondheim, Norway
| | - Nicolas Denis-Lagache
- Contrôle de la Réponse Immune B et des Lymphoproliférations (CBRIL), UMR CNRS 7276 INSERM 1262, Centre de Biologie et de Recherche en Santé (CBRS), Faculté de Limoges, 2 rue du Dr. Marcland, 87000, Limoges, France
| | - Michel Cogné
- Contrôle de la Réponse Immune B et des Lymphoproliférations (CBRIL), UMR CNRS 7276 INSERM 1262, Centre de Biologie et de Recherche en Santé (CBRS), Faculté de Limoges, 2 rue du Dr. Marcland, 87000, Limoges, France
| | - Geir Slupphaug
- Proteomics and Modomics Experimental Core (PROMEC), Department of Cancer Research and Molecular Medicine, Laboratory Centre, Norwegian University of Science and Technology (NTNU), 5th Floor. Erling Skjalgssons gt. 1, 7491, Trondheim, Norway
| | - Laurence Briant
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, UMR 9004, Université de Montpellier, 1919 Route de Mende, 34293, Montpellier Cedex 5, France
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19
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Kara H, Chazal N, Bouaziz S. Is Uracil-DNA Glycosylase UNG2 a New Cellular Weapon Against HIV-1? Curr HIV Res 2020; 17:148-160. [PMID: 31433761 DOI: 10.2174/1570162x17666190821154331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 01/12/2023]
Abstract
Uracil-DNA glycosylase-2 (UNG2) is a DNA repair protein that removes uracil from single and double-stranded DNA through a basic excision repair process. UNG2 is packaged into new virions by interaction with integrase (IN) and is needed during the early stages of the replication cycle. UNG2 appears to play both a positive and negative role during HIV-1 replication; UNG2 improves the fidelity of reverse transcription but the nuclear isoform of UNG2 participates in the degradation of cDNA and the persistence of the cellular genome by repairing its uracil mismatches. In addition, UNG2 is neutralized by Vpr, which redirects it to the proteasome for degradation, suggesting that UNG2 may be a new cellular restriction factor. So far, we have not understood why HIV-1 imports UNG2 via its IN and why it causes degradation of endogenous UNG2 by redirecting it to the proteasome via Vpr. In this review, we propose to discuss the ambiguous role of UNG2 during the HIV-1 replication cycle.
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Affiliation(s)
- Hesna Kara
- Cibles Therapeutiques et Conception de Medicaments (CiTCoM), CNRS UMR8038, Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, Paris, France
| | - Nathalie Chazal
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR9004, Universite de Montpellier, Montpellier, France
| | - Serge Bouaziz
- Cibles Therapeutiques et Conception de Medicaments (CiTCoM), CNRS UMR8038, Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, Paris, France
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20
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Richer AL, Riemondy KA, Hardie L, Hesselberth JR. Simultaneous measurement of biochemical phenotypes and gene expression in single cells. Nucleic Acids Res 2020; 48:e59. [PMID: 32286626 PMCID: PMC7261187 DOI: 10.1093/nar/gkaa240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/16/2020] [Accepted: 04/01/2020] [Indexed: 12/13/2022] Open
Abstract
Methods to measure heterogeneity among cells are rapidly transforming our understanding of biology but are currently limited to molecular abundance measurements. We developed an approach to simultaneously measure biochemical activities and mRNA abundance in single cells to understand the heterogeneity of DNA repair activities across thousands of human lymphocytes, identifying known and novel cell-type-specific DNA repair phenotypes.
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Affiliation(s)
- Amanda L Richer
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
- Molecular Biology Program
| | - Kent A Riemondy
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Lakotah Hardie
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
| | - Jay R Hesselberth
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
- Molecular Biology Program
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
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21
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Stratigopoulou M, van Dam TP, Guikema JEJ. Base Excision Repair in the Immune System: Small DNA Lesions With Big Consequences. Front Immunol 2020; 11:1084. [PMID: 32547565 PMCID: PMC7272602 DOI: 10.3389/fimmu.2020.01084] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022] Open
Abstract
The integrity of the genome is under constant threat of environmental and endogenous agents that cause DNA damage. Endogenous damage is particularly pervasive, occurring at an estimated rate of 10,000–30,000 per cell/per day, and mostly involves chemical DNA base lesions caused by oxidation, depurination, alkylation, and deamination. The base excision repair (BER) pathway is primary responsible for removing and repairing these small base lesions that would otherwise lead to mutations or DNA breaks during replication. Next to preventing DNA mutations and damage, the BER pathway is also involved in mutagenic processes in B cells during immunoglobulin (Ig) class switch recombination (CSR) and somatic hypermutation (SHM), which are instigated by uracil (U) lesions derived from activation-induced cytidine deaminase (AID) activity. BER is required for the processing of AID-induced lesions into DNA double strand breaks (DSB) that are required for CSR, and is of pivotal importance for determining the mutagenic outcome of uracil lesions during SHM. Although uracils are generally efficiently repaired by error-free BER, this process is surprisingly error-prone at the Ig loci in proliferating B cells. Breakdown of this high-fidelity process outside of the Ig loci has been linked to mutations observed in B-cell tumors and DNA breaks and chromosomal translocations in activated B cells. Next to its role in preventing cancer, BER has also been implicated in immune tolerance. Several defects in BER components have been associated with autoimmune diseases, and animal models have shown that BER defects can cause autoimmunity in a B-cell intrinsic and extrinsic fashion. In this review we discuss the contribution of BER to genomic integrity in the context of immune receptor diversification, cancer and autoimmune diseases.
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Affiliation(s)
- Maria Stratigopoulou
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Tijmen P van Dam
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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22
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Kim DV, Makarova AV, Miftakhova RR, Zharkov DO. Base Excision DNA Repair Deficient Cells: From Disease Models to Genotoxicity Sensors. Curr Pharm Des 2020; 25:298-312. [PMID: 31198112 DOI: 10.2174/1381612825666190319112930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/13/2019] [Indexed: 12/29/2022]
Abstract
Base excision DNA repair (BER) is a vitally important pathway that protects the cell genome from many kinds of DNA damage, including oxidation, deamination, and hydrolysis. It involves several tightly coordinated steps, starting from damaged base excision and followed by nicking one DNA strand, incorporating an undamaged nucleotide, and DNA ligation. Deficiencies in BER are often embryonic lethal or cause morbid diseases such as cancer, neurodegeneration, or severe immune pathologies. Starting from the early 1980s, when the first mammalian cell lines lacking BER were produced by spontaneous mutagenesis, such lines have become a treasure trove of valuable information about the mechanisms of BER, often revealing unexpected connections with other cellular processes, such as antibody maturation or epigenetic demethylation. In addition, these cell lines have found an increasing use in genotoxicity testing, where they provide increased sensitivity and representativity to cell-based assay panels. In this review, we outline current knowledge about BER-deficient cell lines and their use.
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Affiliation(s)
- Daria V Kim
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russian Federation
| | - Alena V Makarova
- RAS Institute of Molecular Genetics, 2 Kurchatova Sq., Moscow 123182, Russian Federation
| | - Regina R Miftakhova
- Kazan Federal University, 18 Kremlevsakaya St., Kazan 420008, Russian Federation
| | - Dmitry O Zharkov
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russian Federation.,SB RAS Institute of Chemical Biology and Fu ndamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russian Federation
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23
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Generation of a Mouse Model Lacking the Non-Homologous End-Joining Factor Mri/Cyren. Biomolecules 2019; 9:biom9120798. [PMID: 31795137 PMCID: PMC6995585 DOI: 10.3390/biom9120798] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/23/2019] [Accepted: 11/26/2019] [Indexed: 11/17/2022] Open
Abstract
Classical non-homologous end joining (NHEJ) is a molecular pathway that detects, processes, and ligates DNA double-strand breaks (DSBs) throughout the cell cycle. Mutations in several NHEJ genes result in neurological abnormalities and immunodeficiency both in humans and mice. The NHEJ pathway is required for V(D)J recombination in developing B and T lymphocytes, and for class switch recombination in mature B cells. The Ku heterodimer formed by Ku70 and Ku80 recognizes DSBs and facilitates the recruitment of accessory factors (e.g., DNA-PKcs, Artemis, Paxx and Mri/Cyren) and downstream core factor subunits X-ray repair cross-complementing group 4 (XRCC4), XRCC4-like factor (XLF), and DNA ligase 4 (Lig4). Accessory factors might be dispensable for the process, depending on the genetic background and DNA lesion type. To determine the physiological role of Mri in DNA repair and development, we introduced a frame-shift mutation in the Mri gene in mice. We then analyzed the development of Mri-deficient mice as well as wild type and immunodeficient controls. Mice lacking Mri possessed reduced levels of class switch recombination in B lymphocytes and slow proliferation of neuronal progenitors when compared to wild type littermates. Human cell lines lacking Mri were as sensitive to DSBs as the wild type controls. Overall, we concluded that Mri/Cyren is largely dispensable for DNA repair and mouse development.
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24
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Sarno A, Lundbæk M, Liabakk NB, Aas PA, Mjelle R, Hagen L, Sousa MML, Krokan HE, Kavli B. Uracil-DNA glycosylase UNG1 isoform variant supports class switch recombination and repairs nuclear genomic uracil. Nucleic Acids Res 2019; 47:4569-4585. [PMID: 30838409 PMCID: PMC6511853 DOI: 10.1093/nar/gkz145] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 01/18/2019] [Accepted: 02/25/2019] [Indexed: 11/23/2022] Open
Abstract
UNG is the major uracil-DNA glycosylase in mammalian cells and is involved in both error-free base excision repair of genomic uracil and mutagenic uracil-processing at the antibody genes. However, the regulation of UNG in these different processes is currently not well understood. The UNG gene encodes two isoforms, UNG1 and UNG2, each possessing unique N-termini that mediate translocation to the mitochondria and the nucleus, respectively. A strict subcellular localization of each isoform has been widely accepted despite a lack of models to study them individually. To determine the roles of each isoform, we generated and characterized several UNG isoform-specific mouse and human cell lines. We identified a distinct UNG1 isoform variant that is targeted to the cell nucleus where it supports antibody class switching and repairs genomic uracil. We propose that the nuclear UNG1 variant, which in contrast to UNG2 lacks a PCNA-binding motif, may be specialized to act on ssDNA through its ability to bind RPA. RPA-coated ssDNA regions include both transcribed antibody genes that are targets for deamination by AID and regions in front of the moving replication forks. Our findings provide new insights into the function of UNG isoforms in adaptive immunity and DNA repair.
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Affiliation(s)
- Antonio Sarno
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Marie Lundbæk
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Nina Beate Liabakk
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Per Arne Aas
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Robin Mjelle
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Lars Hagen
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Mirta M L Sousa
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Core Facility for Proteomics and Modomics at NTNU and the Central Norway Regional Health Authority
| | - Hans E Krokan
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
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25
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Serebrenik AA, Starrett GJ, Leenen S, Jarvis MC, Shaban NM, Salamango DJ, Nilsen H, Brown WL, Harris RS. The deaminase APOBEC3B triggers the death of cells lacking uracil DNA glycosylase. Proc Natl Acad Sci U S A 2019; 116:22158-22163. [PMID: 31611371 PMCID: PMC6825264 DOI: 10.1073/pnas.1904024116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human cells express up to 9 active DNA cytosine deaminases with functions in adaptive and innate immunity. Many cancers manifest an APOBEC mutation signature and APOBEC3B (A3B) is likely the main enzyme responsible. Although significant numbers of APOBEC signature mutations accumulate in tumor genomes, the majority of APOBEC-catalyzed uracil lesions are probably counteracted in an error-free manner by the uracil base excision repair pathway. Here, we show that A3B-expressing cells can be selectively killed by inhibiting uracil DNA glycosylase 2 (UNG) and that this synthetic lethal phenotype requires functional mismatch repair (MMR) proteins and p53. UNG knockout human 293 and MCF10A cells elicit an A3B-dependent death. This synthetic lethal phenotype is dependent on A3B catalytic activity and reversible by UNG complementation. A3B expression in UNG-null cells causes a buildup of genomic uracil, and the ensuing lethality requires processing of uracil lesions (likely U/G mispairs) by MSH2 and MLH1 (likely noncanonical MMR). Cancer cells expressing high levels of endogenous A3B and functional p53 can also be killed by expressing an UNG inhibitor. Taken together, UNG-initiated base excision repair is a major mechanism counteracting genomic mutagenesis by A3B, and blocking UNG is a potential strategy for inducing the selective death of tumors.
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Affiliation(s)
- Artur A Serebrenik
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Gabriel J Starrett
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
- Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD 20892
| | - Sterre Leenen
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
- Department of Radiation Oncology, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Matthew C Jarvis
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Nadine M Shaban
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Daniel J Salamango
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, University of Oslo, 1478 Lørenskog, Norway
- Akershus University Hospital, 1478 Lørenskog, Norway
| | - William L Brown
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455;
- Howard Hughes Medical Institute, Minneapolis, MN 55455
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26
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Boldinova EO, Khairullin RF, Makarova AV, Zharkov DO. Isoforms of Base Excision Repair Enzymes Produced by Alternative Splicing. Int J Mol Sci 2019; 20:ijms20133279. [PMID: 31277343 PMCID: PMC6651865 DOI: 10.3390/ijms20133279] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 06/29/2019] [Accepted: 07/02/2019] [Indexed: 02/07/2023] Open
Abstract
Transcripts of many enzymes involved in base excision repair (BER) undergo extensive alternative splicing, but functions of the corresponding alternative splice variants remain largely unexplored. In this review, we cover the studies describing the common alternatively spliced isoforms and disease-associated variants of DNA glycosylases, AP-endonuclease 1, and DNA polymerase beta. We also discuss the roles of alternative splicing in the regulation of their expression, catalytic activities, and intracellular transport.
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Affiliation(s)
| | - Rafil F Khairullin
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 9 Parizhskoy Kommuny Str., 420012 Kazan, Russia
| | - Alena V Makarova
- RAS Institute of Molecular Genetics, 2 Kurchatova Sq., 123182 Moscow, Russia.
| | - Dmitry O Zharkov
- Novosibirsk State University, 1 Pirogova St., 630090 Novosibirsk, Russia.
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia.
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27
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Alekseeva IV, Davletgildeeva AT, Arkova OV, Kuznetsov NA, Fedorova OS. The impact of single-nucleotide polymorphisms of human apurinic/apyrimidinic endonuclease 1 on specific DNA binding and catalysis. Biochimie 2019; 163:73-83. [PMID: 31150756 DOI: 10.1016/j.biochi.2019.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/23/2019] [Indexed: 10/26/2022]
Abstract
Human apurinic/apyrimidinic (AP) endonuclease APE1 is a crucial enzyme of the base excision repair (BER) pathway, which is in charge of recognition and initiation of removal of AP-sites in DNA. It is known that some single-nucleotide polymorphism (SNP) variants of APE1 have a reduced activity as compared to wild-type APE1. It has been hypothesized that genetic variation in APE1 might be responsible for an increased risk of some types of cancer. In the present work, analysis of SNPs of the APE1 gene was performed to select the set of variants having substitutions of amino acid residues on the surface of the enzyme globule and in the DNA-binding site, thereby affecting protein-protein interactions or the catalytic reaction, respectively. For seven APE1 variants (R221C, N222H, R237A, G241R, M270T, R274Q, and P311S), conformational dynamics and catalytic activities were examined. The conformational changes in the molecules of APE1 variants and in a DNA substrate were recorded as fluorescence changes of Trp and 2-aminopurine residues, respectively, using the stopped-flow technique. The results made it possible to determine the kinetic mechanism underlying the interactions of the APE1 variants with DNA substrates, to calculate the rate constants of the elementary stages, and to identify the stages of the process affected by mutation.
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Affiliation(s)
- Irina V Alekseeva
- Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk, 630090, Russia
| | - Anastasiia T Davletgildeeva
- Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk, 630090, Russia; Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia
| | - Olga V Arkova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave., Novosibirsk, 630090, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk, 630090, Russia; Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia.
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk, 630090, Russia; Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia.
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28
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Zanotti KJ, Maul RW, Yang W, Gearhart PJ. DNA Breaks in Ig V Regions Are Predominantly Single Stranded and Are Generated by UNG and MSH6 DNA Repair Pathways. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2019; 202:1573-1581. [PMID: 30665938 PMCID: PMC6382588 DOI: 10.4049/jimmunol.1801183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/16/2018] [Indexed: 11/19/2022]
Abstract
Antibody diversity is initiated by activation-induced deaminase (AID), which deaminates cytosine to uracil in DNA. Uracils in the Ig gene loci can be recognized by uracil DNA glycosylase (UNG) or mutS homologs 2 and 6 (MSH2-MSH6) proteins, and then processed into DNA breaks. Breaks in switch regions of the H chain locus cause isotype switching and have been extensively characterized as staggered and blunt double-strand breaks. However, breaks in V regions that arise during somatic hypermutation are poorly understood. In this study, we characterize AID-dependent break formation in JH introns from mouse germinal center B cells. We used a ligation-mediated PCR assay to detect single-strand breaks and double-strand breaks that were either staggered or blunt. In contrast to switch regions, V regions contained predominantly single-strand breaks, which peaked 10 d after immunization. We then examined the pathways used to generate these breaks in UNG- and MSH6-deficient mice. Surprisingly, both DNA repair pathways contributed substantially to break formation, and in the absence of both UNG and MSH6, the frequency of breaks was severely reduced. When the breaks were sequenced and mapped, they were widely distributed over a 1000-bp intron region downstream of JH3 and JH4 exons and were unexpectedly located at all 4 nt. These data suggest that during DNA repair, nicks are generated at distal sites from the original deaminated cytosine, and these repair intermediates could generate both faithful and mutagenic repair. During mutagenesis, single-strand breaks would allow entry for low-fidelity DNA polymerases to generate somatic hypermutation.
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Affiliation(s)
- Kimberly J Zanotti
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Robert W Maul
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - William Yang
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Patricia J Gearhart
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
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29
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Ye F, Wang H, Liu J, Cheng Q, Chen X, Chen H. Genetic polymorphism (rs246079) of the DNA repair gene uracil N-glycosylase is associated with increased risk of cervical carcinoma in a Chinese population. Medicine (Baltimore) 2018; 97:e13694. [PMID: 30572497 PMCID: PMC6319868 DOI: 10.1097/md.0000000000013694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of this case-control study was to clarify the relationship between uracil N-glycosylase (UNG) rs3219218 and rs246079 genotypes and risk of cervical squamous cell cancer (CSCC). Modified polymerase chain reaction-mismatch amplification (MA-PCR) was applied for genotyping UNG rs3219218 (A/G) and UNG rs246079 (A/G) polymorphisms in 400 CSCC, 400 cervical intraepithelial neoplasia (CIN) III, and 1200 normal controls. We observed no association between the UNG rs3219218 (A/G) polymorphism and risk of CIN III or CSCC. However, risk of CIN III (odds ratio [OR] = 1.58) and CSCC (OR = 2.08) was significantly increased in cases with the homozygous GG genotype of UNG rs246079. At the UNG rs246079 (A/G) locus, individuals with the G allele or G carrier (GG + AG) genotype were at higher risk for CIN III (OR = 1.34) and CSCC (OR = 1.55). In the high-risk HPV (HR-HPV) positive group, homozygous GG of the UNG rs246079 genotype was associated with significantly increased risk of CSCC (OR = 2.37) and CIN III (OR = 1.81). Meanwhile, the proportion of G allele was significantly increased in CIN III (49.2%, OR = 1.33) and CSCC (52.5%, OR = 1.50) groups. G allele or G carrier (GG + AG) genotype was identified as a high-risk factor in CSCC (OR = 1.67) while in the CIN III group, no major differences were evident relative to the control group (OR = 1.45). A particularly high level of enrichment grouping was evident according to the number of sexual partners in the CIN III (P = .036) and CSCC (P = .001) groups. Our data clearly suggest an association between UNG rs246079 (A/G) and CSCC carcinogenesis, supporting the potential application of this polymorphism as a genetic biomarker for early prediction of cervical carcinoma.
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Affiliation(s)
- Feng Ye
- Women's Reproductive Health Key Laboratory of Zhejiang Province
| | - Hanzhi Wang
- Women's Reproductive Health Key Laboratory of Zhejiang Province
| | - Jia Liu
- Department of Obstetrics and Gynecology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, P.R. China
| | - Qi Cheng
- Women's Reproductive Health Key Laboratory of Zhejiang Province
| | - Xiaojing Chen
- Women's Reproductive Health Key Laboratory of Zhejiang Province
| | - Huaizeng Chen
- Women's Reproductive Health Key Laboratory of Zhejiang Province
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30
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The mesophilic archaeon Methanosarcina acetivorans counteracts uracil in DNA with multiple enzymes: EndoQ, ExoIII, and UDG. Sci Rep 2018; 8:15791. [PMID: 30361558 PMCID: PMC6202378 DOI: 10.1038/s41598-018-34000-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/25/2018] [Indexed: 02/04/2023] Open
Abstract
Cytosine deamination into uracil is one of the most prevalent and pro-mutagenic forms of damage to DNA. Base excision repair is a well-known process of uracil removal in DNA, which is achieved by uracil DNA glycosylase (UDG) that is found in all three domains of life. However, other strategies for uracil removal seem to have been evolved in Archaea. Exonuclease III (ExoIII) from the euryarchaeon Methanothermobacter thermautotrophicus has been described to exhibit endonuclease activity toward uracil-containing DNA. Another uracil-acting protein, endonuclease Q (EndoQ), was recently identified from the euryarchaeon Pyrococcus furiosus. Here, we describe the uracil-counteracting system in the mesophilic euryarchaeon Methanosarcina acetivorans through genomic sequence analyses and biochemical characterizations. Three enzymes, UDG, ExoIII, and EndoQ, from M. acetivorans exhibited uracil cleavage activities in DNA with a distinct range of substrate specificities in vitro, and the transcripts for these three enzymes were detected in the M. acetivorans cells. Thus, this organism appears to conduct uracil repair using at least three distinct pathways. Distribution of the homologs of these uracil-targeting proteins in Archaea showed that this tendency is not restricted to M. acetivorans, but is prevalent and diverse in most Archaea. This work further underscores the importance of uracil-removal systems to maintain genome integrity in Archaea, including 'UDG lacking' organisms.
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31
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Moore CL, Papa LJ, Shoulders MD. A Processive Protein Chimera Introduces Mutations across Defined DNA Regions In Vivo. J Am Chem Soc 2018; 140:11560-11564. [PMID: 29991261 PMCID: PMC6166643 DOI: 10.1021/jacs.8b04001] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Laboratory time scale evolution in vivo relies on the generation of large, mutationally diverse gene libraries to rapidly explore biomolecule sequence landscapes. Traditional global mutagenesis methods are problematic because they introduce many off-target mutations that are often lethal and can engender false positives. We report the development and application of the MutaT7 chimera, a potent and highly targeted in vivo mutagenesis agent. MutaT7 utilizes a DNA-damaging cytidine deaminase fused to a processive RNA polymerase to continuously direct mutations to specific, well-defined DNA regions of any relevant length. MutaT7 thus provides a mechanism for in vivo targeted mutagenesis across multi-kb DNA sequences. MutaT7 should prove useful in diverse organisms, opening the door to new types of in vivo evolution experiments.
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Affiliation(s)
- Christopher L Moore
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Louis J Papa
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Matthew D Shoulders
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
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32
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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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33
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Galicia G, Lee DSW, Ramaglia V, Ward LA, Yam JY, Leung LYT, Li R, Handy M, Zhang J, Drohomyrecky PC, Lancaster E, Bar-Or A, Martin A, Gommerman JL. Isotype-Switched Autoantibodies Are Necessary To Facilitate Central Nervous System Autoimmune Disease in Aicda−/− and Ung−/− Mice. THE JOURNAL OF IMMUNOLOGY 2018; 201:1119-1130. [DOI: 10.4049/jimmunol.1700729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/02/2018] [Indexed: 12/30/2022]
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Czarny P, Wigner P, Strycharz J, Watala C, Swiderska E, Synowiec E, Galecki P, Talarowska M, Szemraj J, Su KP, Sliwinski T. Single-nucleotide polymorphisms of uracil-processing genes affect the occurrence and the onset of recurrent depressive disorder. PeerJ 2018; 6:e5116. [PMID: 29967751 PMCID: PMC6025148 DOI: 10.7717/peerj.5116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/07/2018] [Indexed: 12/27/2022] Open
Abstract
Depressive disorders (DD) are known to be associated with increased DNA damage, the impairment of DNA damage repair, and the presence of single-nucleotide polymorphisms (SNPs) in DNA damage repair genes. Some indirect evidence also suggests that uracil metabolism may be disrupted in depressed patients. Therefore, the current study genotypes three SNPs localized in genes encoding uracil-processing proteins: two glycosylases, i.e., UNG g.7245G>C (rs34259), SMUG1 c.-31A>G (rs3087404), and dUTPase, i.e., DUT g.48638795G>T (rs4775748). The polymorphisms were analyzed in 585 DNA samples (282 cases and 303 controls) using TaqMan probes. The G/G genotype and G allele of UNG polymorphism decreased the risk of depression, while the G/C genotype and C allele of the same SNP increased it. It was also found that G/G carriers had their first episode significantly later than the heterozygotes. Although there was no association between the occurrence of depression and the SMUG1 SNP, a significant difference was found between the homozygotes regarding the onset of DD. In conclusion, the SNPs localized in the uracil-processing genes may modulate the occurrence and the onset of depression, which further supports the hypothesis that impairment of DNA damage repair, especially base-excision repair, may play an important role in the pathogenesis of the disease.
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Affiliation(s)
- Piotr Czarny
- Department of Medical Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Paulina Wigner
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Justyna Strycharz
- Department of Medical Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Cezary Watala
- Department of Haemostatic Disorders, Medical University of Lodz, Lodz, Poland
| | - Ewa Swiderska
- Department of Medical Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Ewelina Synowiec
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Piotr Galecki
- Department of Adult Psychiatry, Medical University of Lodz, Lodz, Poland
| | - Monika Talarowska
- Department of Adult Psychiatry, Medical University of Lodz, Lodz, Poland
| | - Janusz Szemraj
- Department of Medical Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Kuan-Pin Su
- Department of Psychiatry and Mind-Body Interface Laboratory (MBI-Lab), China Medical University Hospital, Taichung, Taiwan
| | - Tomasz Sliwinski
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
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35
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Genome-wide mapping reveals that deoxyuridine is enriched in the human centromeric DNA. Nat Chem Biol 2018; 14:680-687. [PMID: 29785056 DOI: 10.1038/s41589-018-0065-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 03/19/2018] [Indexed: 02/06/2023]
Abstract
Uracil in DNA can be generated by cytosine deamination or dUMP misincorporation; however, its distribution in the human genome is poorly understood. Here we present a selective labeling and pull-down technology for genome-wide uracil profiling and identify thousands of uracil peaks in three different human cell lines. Surprisingly, uracil is highly enriched at the centromere of the human genome. Using mass spectrometry, we demonstrate that human centromeric DNA contains a higher level of uracil. We also directly verify the presence of uracil within two centromeric uracil peaks on chromosomes 6 and 11. Moreover, centromeric uracil is preferentially localized within the binding regions of the centromere-specific histone CENP-A and can be excised by human uracil-DNA glycosylase UNG. Collectively, our approaches allow comprehensive analysis of uracil in the human genome and provide robust tools for mapping and future functional studies of uracil in DNA.
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36
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A licensing step links AID to transcription elongation for mutagenesis in B cells. Nat Commun 2018; 9:1248. [PMID: 29593215 PMCID: PMC5871760 DOI: 10.1038/s41467-018-03387-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 02/08/2018] [Indexed: 01/01/2023] Open
Abstract
Activation-induced deaminase (AID) mutates the immunoglobulin (Ig) genes to initiate somatic hypermutation (SHM) and class switch recombination (CSR) in B cells, thus underpinning antibody responses. AID mutates a few hundred other loci, but most AID-occupied genes are spared. The mechanisms underlying productive deamination versus non-productive AID targeting are unclear. Here we show that three clustered arginine residues define a functional AID domain required for SHM, CSR, and off-target activity in B cells without affecting AID deaminase activity or Escherichia coli mutagenesis. Both wt AID and mutants with single amino acid replacements in this domain broadly associate with Spt5 and chromatin and occupy the promoter of AID target genes. However, mutant AID fails to occupy the corresponding gene bodies and loses association with transcription elongation factors. Thus AID mutagenic activity is determined not by locus occupancy but by a licensing mechanism, which couples AID to transcription elongation. Activation-induced deaminase (AID) is important for inducing desirable mutations at the B cell receptor genes for effective antibody responses. Here the authors show that three key arginine residues of AID link AID-chromatin association with transcription elongation to license AID for specific mutagenesis in B cells.
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37
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Deficiency in the DNA glycosylases UNG1 and OGG1 does not potentiate c-Myc-induced B-cell lymphomagenesis. Exp Hematol 2018; 61:52-58. [PMID: 29496532 DOI: 10.1016/j.exphem.2018.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 11/22/2022]
Abstract
C-Myc overexpression mediates lymphomagenesis; however, secondary genetic lesions are required for its full oncogenic potential. The origin and the mechanism of formation of these mutations are unclear. Using the lacI mutation detection system, we show that secondary mutations occur early in B-cell development and are repaired by Msh2. The mutations at the lacI gene were predominantly at C:G base pairs and CpG motifs, suggesting that they were formed due to cytosine deamination or oxidative damage of G. Therefore, we investigated the role of Ogg1 and UNG glycosylases in c-Myc-driven lymphomagenesis but found that their deficiencies did not influence disease outcome in the Eµ c-Myc mouse model. We also show that Rag proteins do not contribute to secondary lesions in this model. Our work suggests that mutations at C:G base pairs that are repaired primarily by the mismatch repair system arise early in B-cell ontogeny to promote c-Myc-driven lymphomagenesis.
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38
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Gago‐Fuentes R, Xing M, Sæterstad S, Sarno A, Dewan A, Beck C, Bradamante S, Bjørås M, Oksenych V. Normal development of mice lacking PAXX, the paralogue of XRCC4 and XLF. FEBS Open Bio 2018; 8:426-434. [PMID: 29511619 PMCID: PMC5832975 DOI: 10.1002/2211-5463.12381] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/18/2017] [Accepted: 01/04/2018] [Indexed: 02/05/2023] Open
Abstract
DNA repair consists of several cellular pathways which recognize and repair damaged DNA. The classical nonhomologous DNA end-joining (NHEJ) pathway repairs double-strand breaks in DNA. It is required for maturation of both B and T lymphocytes by supporting V(D)J recombination as well as B-cell differentiation during class switch recombination (CSR). Inactivation of NHEJ factors Ku70, Ku80, XRCC4, DNA ligase 4, DNA-PKcs, and Artemis impairs V(D)J recombination and blocks lymphocyte development. Paralogue of XRCC4 and XLF (PAXX) is an accessory NHEJ factor that has a significant impact on the repair of DNA lesions induced by ionizing radiation in human, murine, and chicken cells. However, the role of PAXX during development is poorly understood. To determine the physiological role of PAXX, we deleted part of the Paxx promoter and the first two exons in mice. Further, we compared Paxx-knockout mice with wild-type (WT) and NHEJ-deficient controls including Ku80- and Dna-pkcs-null and severe combined immunodeficiency mice. Surprisingly, Paxx-deficient mice were not distinguishable from the WT littermates; they were the same weight and size, fertility status, had normal spleen, thymus, and bone marrow. Paxx-deficient mice had the same number of chromosomal and chromatid breaks as WT mice. Moreover, Paxx-deficient primary B lymphocytes had the same level of CSR as lymphocytes isolated from WT mice. We concluded that PAXX is dispensable for normal mouse development.
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Affiliation(s)
- Raquel Gago‐Fuentes
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Mengtan Xing
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Siri Sæterstad
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Antonio Sarno
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- St. Olavs HospitalClinic of MedicineTrondheim University HospitalTrondheimNorway
| | - Alisa Dewan
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- Present address:
Centre for Immune Regulation and Department of ImmunologyOslo University Hospital‐RikshospitaletUniversity of OsloOsloNorway
- Present address:
KG Jebsen Coeliac Disease Research CentreUniversity of OsloOsloNorway
| | - Carole Beck
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Stefano Bradamante
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Magnar Bjørås
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- Department of MicrobiologyOslo University HospitalUniversity of OsloOsloNorway
| | - Valentyn Oksenych
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- St. Olavs HospitalClinic of MedicineTrondheim University HospitalTrondheimNorway
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39
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Álvarez-Prado ÁF, Pérez-Durán P, Pérez-García A, Benguria A, Torroja C, de Yébenes VG, Ramiro AR. A broad atlas of somatic hypermutation allows prediction of activation-induced deaminase targets. J Exp Med 2018; 215:761-771. [PMID: 29374026 PMCID: PMC5839764 DOI: 10.1084/jem.20171738] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/22/2017] [Accepted: 12/21/2017] [Indexed: 12/18/2022] Open
Abstract
Activation-induced deaminase (AID) initiates antibody diversification in germinal center (GC) B cells through the deamination of cytosines on immunoglobulin genes. AID can also target other regions in the genome, triggering mutations or chromosome translocations, with major implications for oncogenic transformation. However, understanding the specificity of AID has proved extremely challenging. We have sequenced at very high depth >1,500 genomic regions from GC B cells and identified 275 genes targeted by AID, including 30 of the previously known 35 AID targets. We have also identified the most highly mutated hotspot for AID activity described to date. Furthermore, integrative analysis of the molecular features of mutated genes coupled to machine learning has produced a powerful predictive tool for AID targets. We also have found that base excision repair and mismatch repair back up each other to faithfully repair AID-induced lesions. Finally, our data establish a novel link between AID mutagenic activity and lymphomagenesis.
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Affiliation(s)
- Ángel F Álvarez-Prado
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Pablo Pérez-Durán
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Arantxa Pérez-García
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Alberto Benguria
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Carlos Torroja
- Bioinformatics Unit, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Virginia G de Yébenes
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Almudena R Ramiro
- B Cell Biology Lab, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
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40
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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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41
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Du W, Li J, Xiao F, Yu R, Jiang J. A label-free and highly sensitive strategy for uracil-DNA glycosylase activity detection based on stem-loop primer-mediated exponential amplification (SPEA). Anal Chim Acta 2017; 991:127-132. [PMID: 29031294 DOI: 10.1016/j.aca.2017.08.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/23/2017] [Accepted: 08/28/2017] [Indexed: 11/19/2022]
Abstract
Uracil-DNA glycosylase (UDG) plays essential roles in base excision repair (BER) pathway by eliminating uracil from DNA to sustain the genome integrity. Sensitive detection of UDG activity is of great significance in the study of many fundamental biochemical processes and clinical applications. We develop a label-free method for UDG activity detection using stem-loop primer-mediated exponential amplification (SPEA). In the presence of active UDG, the uracil base in helper hairpin probe (HP) can be excised to generate an abasic site (AP site), which can be cleaved by endonuclease IV (Endo IV) with a blocked primer released. This primer then triggers the strand displacement reaction to produce a dumb-bell structure DNA, which can initiate a loop-mediated isothermal amplification (LAMP) reaction. This reaction generates a large number of long double-strand DNA replicates, which can be stained by SYBR Green (SG) I to deliver enhanced fluorescence for quantitative detection of UDG activity. A linear range from 0.001 U/mL to 1 U/mL and a detection limit down to 0.00068 U/mL are achieved. This strategy has also been demonstrated for UDG assay in complex cell lysates, implying its great potential for UDG based clinical diagnostics and therapeutics.
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Affiliation(s)
- Wenfang Du
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China
| | - Junjie Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China
| | - Fubing Xiao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China
| | - Ruqin Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
| | - Jianhui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
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42
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Alsøe L, Sarno A, Carracedo S, Domanska D, Dingler F, Lirussi L, SenGupta T, Tekin NB, Jobert L, Alexandrov LB, Galashevskaya A, Rada C, Sandve GK, Rognes T, Krokan HE, Nilsen H. Uracil Accumulation and Mutagenesis Dominated by Cytosine Deamination in CpG Dinucleotides in Mice Lacking UNG and SMUG1. Sci Rep 2017; 7:7199. [PMID: 28775312 PMCID: PMC5543110 DOI: 10.1038/s41598-017-07314-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/23/2017] [Indexed: 12/30/2022] Open
Abstract
Both a DNA lesion and an intermediate for antibody maturation, uracil is primarily processed by base excision repair (BER), either initiated by uracil-DNA glycosylase (UNG) or by single-strand selective monofunctional uracil DNA glycosylase (SMUG1). The relative in vivo contributions of each glycosylase remain elusive. To assess the impact of SMUG1 deficiency, we measured uracil and 5-hydroxymethyluracil, another SMUG1 substrate, in Smug1−/− mice. We found that 5-hydroxymethyluracil accumulated in Smug1−/− tissues and correlated with 5-hydroxymethylcytosine levels. The highest increase was found in brain, which contained about 26-fold higher genomic 5-hydroxymethyluracil levels than the wild type. Smug1−/− mice did not accumulate uracil in their genome and Ung−/− mice showed slightly elevated uracil levels. Contrastingly, Ung−/−Smug1−/− mice showed a synergistic increase in uracil levels with up to 25-fold higher uracil levels than wild type. Whole genome sequencing of UNG/SMUG1-deficient tumours revealed that combined UNG and SMUG1 deficiency leads to the accumulation of mutations, primarily C to T transitions within CpG sequences. This unexpected sequence bias suggests that CpG dinucleotides are intrinsically more mutation prone. In conclusion, we showed that SMUG1 efficiently prevent genomic uracil accumulation, even in the presence of UNG, and identified mutational signatures associated with combined UNG and SMUG1 deficiency.
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Affiliation(s)
- Lene Alsøe
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway
| | - Antonio Sarno
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,The Liaison Committee for Education, Research and Innovation in Central Norway, Trondheim, Norway
| | - Sergio Carracedo
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway
| | - Diana Domanska
- Department of Informatics, University of Oslo, PO Box 1080 Blindern, NO-0316, Oslo, Norway
| | | | - Lisa Lirussi
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway
| | - Tanima SenGupta
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway
| | - Nuriye Basdag Tekin
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway
| | - Laure Jobert
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway.,Akershus University Hospital, Lørenskog, Norway.,LifeTechnologies AS, Ullernschauseen 52, 0379, Oslo, Norway
| | - Ludmil B Alexandrov
- Theoretical Biology and Biophysics (T-6), Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.,Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.,University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, 87102, USA
| | - Anastasia Galashevskaya
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Geir Kjetil Sandve
- Department of Informatics, University of Oslo, PO Box 1080 Blindern, NO-0316, Oslo, Norway
| | - Torbjørn Rognes
- Department of Informatics, University of Oslo, PO Box 1080 Blindern, NO-0316, Oslo, Norway.,Department of Microbiology, Oslo University Hospital, Rikshospitalet, PO Box 4950 Nydalen, NO-0424, Oslo, Norway
| | - Hans E Krokan
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, Ahus Campus, University of Oslo, Oslo, Norway. .,Akershus University Hospital, Lørenskog, Norway.
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43
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Origins of mtDNA mutations in ageing. Essays Biochem 2017; 61:325-337. [PMID: 28698307 DOI: 10.1042/ebc20160090] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/24/2017] [Accepted: 05/26/2017] [Indexed: 12/21/2022]
Abstract
MtDNA mutations are one of the hallmarks of ageing and age-related diseases. It is well established that somatic point mutations accumulate in mtDNA of multiple organs and tissues with increasing age and heteroplasmy is universal in mammals. However, the origin of these mutations remains controversial. The long-lasting hypothesis stating that mtDNA mutations emanate from oxidative damage via a self-perpetuating mechanism has been extensively challenged in recent years. Contrary to this initial ascertainment, mtDNA appears to be well protected from action of reactive oxygen species (ROS) through robust protein coating and endomitochondrial microcompartmentalization. Extensive development of scrupulous high-throughput DNA sequencing methods suggests that an imperfect replication process, rather than oxidative lesions are the main sources of mtDNA point mutations, indicating that mtDNA polymerase γ (POLG) might be responsible for the majority of mtDNA mutagenic events. Here, we summarize the recent knowledge in prevention and defence of mtDNA oxidative lesions and discuss the plausible mechanisms of mtDNA point mutation generation and fixation.
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44
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D'Errico M, Parlanti E, Pascucci B, Fortini P, Baccarini S, Simonelli V, Dogliotti E. Single nucleotide polymorphisms in DNA glycosylases: From function to disease. Free Radic Biol Med 2017; 107:278-291. [PMID: 27932076 DOI: 10.1016/j.freeradbiomed.2016.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/25/2016] [Accepted: 12/02/2016] [Indexed: 02/08/2023]
Abstract
Oxidative stress is associated with a growing number of diseases that span from cancer to neurodegeneration. Most oxidatively induced DNA base lesions are repaired by the base excision repair (BER) pathway which involves the action of various DNA glycosylases. There are numerous genome wide studies attempting to associate single-nucleotide polymorphisms (SNPs) with predispositions to various types of disease; often, these common variants do not have significant alterations in their biochemical function and do not exhibit a convincing phenotype. Nevertheless several lines of evidence indicate that SNPs in DNA repair genes may modulate DNA repair capacity and contribute to risk of disease. This overview provides a convincing picture that SNPs of DNA glycosylases that remove oxidatively generated DNA lesions are susceptibility factors for a wide disease spectrum that includes besides cancer (particularly lung, breast and gastrointestinal tract), cochlear/ocular disorders, myocardial infarction and neurodegenerative disorders which can be all grouped under the umbrella of oxidative stress-related pathologies.
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Affiliation(s)
- Mariarosaria D'Errico
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Eleonora Parlanti
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Barbara Pascucci
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Via Salaria, Km 29,300, 00016 Monterotondo Stazione, Rome, Italy
| | - Paola Fortini
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Sara Baccarini
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Valeria Simonelli
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Eugenia Dogliotti
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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45
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Gold B. Somatic mutations in cancer: Stochastic versus predictable. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2017; 814:37-46. [PMID: 28137366 DOI: 10.1016/j.mrgentox.2016.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/01/2023]
Abstract
The origins of human cancers remain unclear except for a limited number of potent environmental mutagens, such as tobacco and UV light, and in rare cases, familial germ line mutations that affect tumor suppressor genes or oncogenes. A significant component of cancer etiology has been deemed stochastic and correlated with the number of stem cells in a tissue, the number of times the stem cells divide and a low incidence of random DNA polymerase errors that occur during each cell division. While somatic mutations occur during each round of DNA replication, mutations in cancer driver genes are not stochastic. Out of a total of 2843 codons, 1031 can be changed to stop codons by a single base substitution in the tumor suppressor APC gene, which is mutated in 76% of colorectal cancers (CRC). However, the nonsense mutations, which comprise 65% of all the APC driver mutations in CRC, are not random: 43% occur at Arg CGA codons, although they represent <3% of the codons. In TP53, CGA codons comprise <3% of the total 393 codons but they account for 72% and 39% of the mutations in CRC and ovarian cancer OVC, respectively. This mutation pattern is consistent with the kinetically slow, but not stochastic, hydrolytic deamination of 5-methylcytosine residues at specific methylated CpG sites to afford T·G mismatches that lead to C→T transitions and stop codons at CGA. Analysis of nonsense mutations in CRC, OVC and a number of other cancers indicates the need to expand the predictable risk factors for cancer to include, in addition to random polymerase errors, the methylation status of gene body CGA codons in tumor suppressor genes.
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Affiliation(s)
- Barry Gold
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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46
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Shelton J, Lu X, Hollenbaugh JA, Cho JH, Amblard F, Schinazi RF. Metabolism, Biochemical Actions, and Chemical Synthesis of Anticancer Nucleosides, Nucleotides, and Base Analogs. Chem Rev 2016; 116:14379-14455. [PMID: 27960273 DOI: 10.1021/acs.chemrev.6b00209] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nucleoside, nucleotide, and base analogs have been in the clinic for decades to treat both viral pathogens and neoplasms. More than 20% of patients on anticancer chemotherapy have been treated with one or more of these analogs. This review focuses on the chemical synthesis and biology of anticancer nucleoside, nucleotide, and base analogs that are FDA-approved and in clinical development since 2000. We highlight the cellular biology and clinical biology of analogs, drug resistance mechanisms, and compound specificity towards different cancer types. Furthermore, we explore analog syntheses as well as improved and scale-up syntheses. We conclude with a discussion on what might lie ahead for medicinal chemists, biologists, and physicians as they try to improve analog efficacy through prodrug strategies and drug combinations.
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Affiliation(s)
- Jadd Shelton
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
| | - Xiao Lu
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
| | - Joseph A Hollenbaugh
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
| | - Jong Hyun Cho
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
| | - Franck Amblard
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
| | - Raymond F Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine , 1760 Haygood Drive, NE, Atlanta, Georgia 30322, United States
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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: 106] [Impact Index Per Article: 13.3] [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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Baehr CA, Huntoon CJ, Hoang SM, Jerde CR, Karnitz LM. Glycogen Synthase Kinase 3 (GSK-3)-mediated Phosphorylation of Uracil N-Glycosylase 2 (UNG2) Facilitates the Repair of Floxuridine-induced DNA Lesions and Promotes Cell Survival. J Biol Chem 2016; 291:26875-26885. [PMID: 27875297 DOI: 10.1074/jbc.m116.746081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 11/10/2016] [Indexed: 12/23/2022] Open
Abstract
Uracil N-glycosylase 2 (UNG2), the nuclear isoform of UNG, catalyzes the removal of uracil or 5-fluorouracil lesions that accumulate in DNA following treatment with the anticancer agents 5-fluorouracil and 5-fluorodeoxyuridine (floxuridine), a 5-fluorouracil metabolite. By repairing these DNA lesions before they can cause cell death, UNG2 promotes cancer cell survival and is therefore critically involved in tumor resistance to these agents. However, the mechanisms by which UNG2 is regulated remain unclear. Several phosphorylation sites within the N-terminal regulatory domain of UNG2 have been identified, although the effects of these modifications on UNG2 function have not been fully explored, nor have the identities of the kinases involved been determined. Here we show that glycogen synthase kinase 3 (GSK-3) interacts with and phosphorylates UNG2 at Thr60 and that Thr60 phosphorylation requires a Ser64 priming phosphorylation event. We also show that mutating Thr60 or Ser64 to Ala increases the half-life of UNG2, reduces the rate of in vitro uracil excision, and slows UNG2 dissociation from chromatin after DNA replication. Using an UNG2-deficient ovarian cancer cell line that is hypersensitive to floxuridine, we show that GSK-3 phosphorylation facilitates UNG2-dependent repair of floxuridine-induced DNA lesions and promotes tumor cell survival following exposure to this agent. These data suggest that GSK-3 regulates UNG2 and promotes DNA damage repair.
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Affiliation(s)
- Carly A Baehr
- From the Departments of Molecular Pharmacology and Experimental Therapeutics and
| | - Catherine J Huntoon
- From the Departments of Molecular Pharmacology and Experimental Therapeutics and.,the Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905-0002
| | - Song-My Hoang
- From the Departments of Molecular Pharmacology and Experimental Therapeutics and
| | - Calvin R Jerde
- From the Departments of Molecular Pharmacology and Experimental Therapeutics and
| | - Larry M Karnitz
- From the Departments of Molecular Pharmacology and Experimental Therapeutics and .,the Division of Oncology Research, Mayo Clinic, Rochester, Minnesota 55905-0002.,Radiation Oncology and
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Kuznetsov NA, Kupryushkin MS, Abramova TV, Kuznetsova AA, Miroshnikova AD, Stetsenko DA, Pyshnyi DV, Fedorova OS. New oligonucleotide derivatives as unreactive substrate analogues and potential inhibitors of human apurinic/apyrimidinic endonuclease APE1. MOLECULAR BIOSYSTEMS 2016; 12:67-75. [PMID: 26548492 DOI: 10.1039/c5mb00692a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human apurinic/apyrimidinic endonuclease APE1 is one of the key enzymes of the base excision DNA repair system. The main biological function of APE1 is the hydrolysis of the phosphodiester bond on the 5'-side of an apurinic/apyrimidinic site (AP-site) to give the 5'-phosphate and 3'-hydroxyl group. It has long been known that AP-sites have mutagenic and cytotoxic effects and their accumulation in DNA is a potential hazard to the cell lifecycle. The structural and biochemical studies of APE1 are complicated by its high catalytic activity towards the AP-site and its cyclic or acyclic analogues. This work has focussed on the design, synthesis and analysis of oligonucleotide derivatives as potentially unreactive APE1 substrates. We have shown that the replacement of oxygen atoms in the phosphate group on the 5'-side from the AP-site analogue tetrahydrofuran (F) considerably decreases the rate of enzymatic hydrolysis of modified oligonucleotides. We have calculated that a N3'-P5' phosphoramidate linkage is hydrolysed about 30 times slower than the native phosphodiester bond while phosphorothioate or primary phosphoramidate linkages are cleaved more than three orders of magnitude slower. The value of IC50 of the oligonucleotide duplex containing a primary phosphoramidate linkage is 2.5 × 10(-7) M, which is in accordance with the APE1 association constant of DNA duplexes containing AP-sites. Thus, it is demonstrated that oligonucleotide duplexes with chemical modifications could be used as unreactive substrates and potential competitive inhibitors of APE1.
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Affiliation(s)
- Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Maxim S Kupryushkin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Tatyana V Abramova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Alexandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Anastasia D Miroshnikova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Dmitry A Stetsenko
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Dmitrii V Pyshnyi
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
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50
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Klungland A, Yang YG. Endogenous DNA Damage and Repair Enzymes: -A short summary of the scientific achievements of Tomas Lindahl, Nobel Laureate in Chemistry 2015. GENOMICS PROTEOMICS & BIOINFORMATICS 2015; 14:122-125. [PMID: 26689322 PMCID: PMC4936663 DOI: 10.1016/j.gpb.2015.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 11/12/2015] [Indexed: 11/25/2022]
Abstract
Tomas Lindahl completed his medical studies at Karolinska Institute in 1970. Yet, his work has always been dedicated to unraveling fundamental mechanisms of DNA decay and DNA repair. His research is characterized with groundbreaking discoveries on the instability of our genome, the identification of novel DNA repair activities, the characterization of DNA repair pathways, and the association to diseases, throughout his 40 years of scientific career.
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Affiliation(s)
- Arne Klungland
- Department of Microbiology, Division of Diagnostics and Intervention, Institute of Clinical Medicine, Oslo University Hospital, Rikshospitalet, Oslo NO-0027, Norway; Department of Molecular Medicine, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo NO-0027, Norway.
| | - Yun-Gui Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
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