1
|
Shilkin ES, Petrova DV, Novikova AA, Boldinova EO, Zharkov DO, Makarova AV. Methylation and hydroxymethylation of cytosine alter activity and fidelity of translesion DNA polymerases. DNA Repair (Amst) 2024; 141:103712. [PMID: 38959714 DOI: 10.1016/j.dnarep.2024.103712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/24/2024] [Accepted: 06/11/2024] [Indexed: 07/05/2024]
Abstract
Epigenetic cytosine methylation covers most of genomic CpG dinucleotides in human cells. In addition to common deamination-mediated mutagenesis at CpG sites, an alternative deamination-independent pathway associated with DNA polymerase activity was previously described. This mutagenesis is characterized by the TCG→TTG mutational signature and is believed to arise from dAMP misincorporation opposite 5-methylcytosine (mC) or its oxidized derivative 5-hydroxymethylcytosine (hmC) by B-family replicative DNA polymerases with disrupted proofreading 3→5'-exonuclease activity. In addition to being less stable and pro-mutagenic themselves, cytosine modifications also increase the risk of adjacent nucleotides damage, including the formation of 8-oxo-2'-deoxyguanosine (8-oxoG), a well-known mutagenic lesion. The effect of cytosine methylation on error-prone DNA polymerases lacking proofreading activity and involved in repair and DNA translesion synthesis remains unexplored. Here we analyze the efficiency and fidelity of translesion Y-family polymerases (Pol κ, Pol η, Pol ι and REV1) and primase-polymerase PrimPol opposite mC and hmC as well as opposite 8-oxoG adjacent to mC in the TCG context. We demonstrate that epigenetic cytosine modifications suppress Pol ι and REV1 activities and lead to increasing dAMP misincorporation by PrimPol, Pol κ and Pol ι in vitro. Cytosine methylation also increases misincorporation of dAMP opposite the adjacent 8-oxoG by PrimPol, decreases the TLS activity of Pol η opposite the lesion but increases dCMP incorporation opposite 8-oxoG by REV1. Altogether, these data suggest that methylation and hydroxymethylation of cytosine alter activity and fidelity of translesion DNA polymerases.
Collapse
Affiliation(s)
- Evgeniy S Shilkin
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow 123182, Russia; Institute of Gene Biology of Russian Academy of Sciences, Moscow 119334, Russia
| | - Daria V Petrova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 63009, Russia
| | - Anna A Novikova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow 123182, Russia; Institute of Gene Biology of Russian Academy of Sciences, Moscow 119334, Russia
| | - Elizaveta O Boldinova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow 123182, Russia; Institute of Gene Biology of Russian Academy of Sciences, Moscow 119334, Russia
| | - Dmitry O Zharkov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 63009, Russia.
| | - Alena V Makarova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Moscow 123182, Russia; Institute of Gene Biology of Russian Academy of Sciences, Moscow 119334, Russia.
| |
Collapse
|
2
|
Araki R, Suga T, Hoki Y, Imadome K, Sunayama M, Kamimura S, Fujita M, Abe M. iPS cell generation-associated point mutations include many C > T substitutions via different cytosine modification mechanisms. Nat Commun 2024; 15:4946. [PMID: 38862540 PMCID: PMC11166658 DOI: 10.1038/s41467-024-49335-5] [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: 04/17/2023] [Accepted: 05/31/2024] [Indexed: 06/13/2024] Open
Abstract
Genomic aberrations are a critical impediment for the safe medical use of iPSCs and their origin and developmental mechanisms remain unknown. Here we find through WGS analysis of human and mouse iPSC lines that genomic mutations are de novo events and that, in addition to unmodified cytosine base prone to deamination, the DNA methylation sequence CpG represents a significant mutation-prone site. CGI and TSS regions show increased mutations in iPSCs and elevated mutations are observed in retrotransposons, especially in the AluY subfamily. Furthermore, increased cytosine to thymine mutations are observed in differentially methylated regions. These results indicate that in addition to deamination of cytosine, demethylation of methylated cytosine, which plays a central role in genome reprogramming, may act mutagenically during iPSC generation.
Collapse
Affiliation(s)
- Ryoko Araki
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan.
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan.
| | - Tomo Suga
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Yuko Hoki
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Kaori Imadome
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Misato Sunayama
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Satoshi Kamimura
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Mayumi Fujita
- Stem Cell Biology Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Masumi Abe
- Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan.
| |
Collapse
|
3
|
Brabson JP, Leesang T, Yap YS, Wang J, Lam MQ, Fang B, Dolgalev I, Barbieri DA, Strippoli V, Bañuelos CP, Mohammad S, Lyon P, Chaudhry S, Donich D, Swirski A, Roberts E, Diaz I, Karl D, Dos Santos HG, Shiekhattar R, Neel BG, Nimer SD, Verdun RE, Bilbao D, Figueroa ME, Cimmino L. Oxidized mC modulates synthetic lethality to PARP inhibitors for the treatment of leukemia. Cell Rep 2023; 42:112027. [PMID: 36848231 PMCID: PMC9989506 DOI: 10.1016/j.celrep.2023.112027] [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: 02/21/2022] [Revised: 10/24/2022] [Accepted: 01/10/2023] [Indexed: 01/25/2023] Open
Abstract
TET2 haploinsufficiency is a driving event in myeloid cancers and is associated with a worse prognosis in patients with acute myeloid leukemia (AML). Enhancing residual TET2 activity using vitamin C increases oxidized 5-methylcytosine (mC) formation and promotes active DNA demethylation via base excision repair (BER), which slows leukemia progression. We utilize genetic and compound library screening approaches to identify rational combination treatment strategies to improve use of vitamin C as an adjuvant therapy for AML. In addition to increasing the efficacy of several US Food and Drug Administration (FDA)-approved drugs, vitamin C treatment with poly-ADP-ribosyl polymerase inhibitors (PARPis) elicits a strong synergistic effect to block AML self-renewal in murine and human AML models. Vitamin-C-mediated TET activation combined with PARPis causes enrichment of chromatin-bound PARP1 at oxidized mCs and γH2AX accumulation during mid-S phase, leading to cell cycle stalling and differentiation. Given that most AML subtypes maintain residual TET2 expression, vitamin C could elicit broad efficacy as a PARPi therapeutic adjuvant.
Collapse
Affiliation(s)
- John P Brabson
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Tiffany Leesang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Yoon Sing Yap
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Jingjing Wang
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Minh Q Lam
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Byron Fang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Igor Dolgalev
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Daniela A Barbieri
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Victoria Strippoli
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Carolina P Bañuelos
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Sofia Mohammad
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Peter Lyon
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Sana Chaudhry
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Dane Donich
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Anna Swirski
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Evan Roberts
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Ivelisse Diaz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Daniel Karl
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Helena Gomes Dos Santos
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Ramin Shiekhattar
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Benjamin G Neel
- Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Stephen D Nimer
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Ramiro E Verdun
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Daniel Bilbao
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Maria E Figueroa
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Luisa Cimmino
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
| |
Collapse
|
4
|
Dubini RA, Korytiaková E, Schinkel T, Heinrichs P, Carell T, Rovó P. 1H NMR Chemical Exchange Techniques Reveal Local and Global Effects of Oxidized Cytosine Derivatives. ACS PHYSICAL CHEMISTRY AU 2022; 2:237-246. [PMID: 35637781 PMCID: PMC9137243 DOI: 10.1021/acsphyschemau.1c00050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 11/29/2022]
Abstract
5-Carboxycytosine (5caC) is a rare epigenetic modification found in nucleic acids of all domains of life. Despite its sparse genomic abundance, 5caC is presumed to play essential regulatory roles in transcription, maintenance and base-excision processes in DNA. In this work, we utilize nuclear magnetic resonance (NMR) spectroscopy to address the effects of 5caC incorporation into canonical DNA strands at multiple pH and temperature conditions. Our results demonstrate that 5caC has a pH-dependent global destabilizing and a base-pair mobility enhancing local impact on dsDNA, albeit without any detectable influence on the ground-state B-DNA structure. Measurement of hybridization thermodynamics and kinetics of 5caC-bearing DNA duplexes highlighted how acidic environment (pH 5.8 and 4.7) destabilizes the double-stranded structure by ∼10-20 kJ mol-1 at 37 °C when compared to the same sample at neutral pH. Protonation of 5caC results in a lower activation energy for the dissociation process and a higher barrier for annealing. Studies on conformational exchange on the microsecond time scale regime revealed a sharply localized base-pair motion involving exclusively the modified site and its immediate surroundings. By direct comparison with canonical and 5-formylcytosine (5fC)-edited strands, we were able to address the impact of the two most oxidized naturally occurring cytosine derivatives in the genome. These insights on 5caC's subtle sensitivity to acidic pH contribute to the long-standing questions of its capacity as a substrate in base excision repair processes and its purpose as an independent, stable epigenetic mark.
Collapse
Affiliation(s)
- Romeo
C. A. Dubini
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
- Center
for Nanoscience (CeNS), Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 5th floor, 80799 Munich, Germany
| | - Eva Korytiaková
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Thea Schinkel
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Pia Heinrichs
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Thomas Carell
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
| | - Petra Rovó
- Faculty
of Chemistry and Pharmacy, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 Munich, Germany
- Center
for Nanoscience (CeNS), Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 5th floor, 80799 Munich, Germany
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| |
Collapse
|
5
|
Rausch C, Zhang P, Casas-Delucchi CS, Daiß JL, Engel C, Coster G, Hastert FD, Weber P, Cardoso M. Cytosine base modifications regulate DNA duplex stability and metabolism. Nucleic Acids Res 2021; 49:12870-12894. [PMID: 34133727 PMCID: PMC8682791 DOI: 10.1093/nar/gkab509] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 12/14/2022] Open
Abstract
DNA base modifications diversify the genome and are essential players in development. Yet, their influence on DNA physical properties and the ensuing effects on genome metabolism are poorly understood. Here, we focus on the interplay of cytosine modifications and DNA processes. We show by a combination of in vitro reactions with well-defined protein compositions and conditions, and in vivo experiments within the complex networks of the cell that cytosine methylation stabilizes the DNA helix, increasing its melting temperature and reducing DNA helicase and RNA/DNA polymerase speed. Oxidation of methylated cytosine, however, reverts the duplex stabilizing and genome metabolic effects to the level of unmodified cytosine. We detect this effect with DNA replication and transcription proteins originating from different species, ranging from prokaryotic and viral to the eukaryotic yeast and mammalian proteins. Accordingly, lack of cytosine methylation increases replication fork speed by enhancing DNA helicase unwinding speed in cells. We further validate that this cannot simply be explained by altered global DNA decondensation, changes in histone marks or chromatin structure and accessibility. We propose that the variegated deposition of cytosine modifications along the genome regulates DNA helix stability, thereby providing an elementary mechanism for local fine-tuning of DNA metabolism.
Collapse
Affiliation(s)
- Cathia Rausch
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
- Center for Tissue Engineering and Stem Cell Research, Guizhou Medical University, Guiyang, Guizhou 550004, China
| | | | - Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Gideon Coster
- Chester Beatty Laboratories, The Institute of Cancer Research, London SW3 6JB, UK
| | - Florian D Hastert
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Patrick Weber
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| |
Collapse
|
6
|
Prasad R, Yen TJ, Bellacosa A. Active DNA demethylation-The epigenetic gatekeeper of development, immunity, and cancer. ADVANCED GENETICS (HOBOKEN, N.J.) 2021; 2:e10033. [PMID: 36618446 PMCID: PMC9744510 DOI: 10.1002/ggn2.10033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 01/11/2023]
Abstract
DNA methylation is a critical process in the regulation of gene expression with dramatic effects in development and continually expanding roles in oncogenesis. 5-Methylcytosine was once considered to be an inherited and stably repressive epigenetic mark, which can be only removed by passive dilution during multiple rounds of DNA replication. However, in the past two decades, physiologically controlled DNA demethylation and deamination processes have been identified, thereby revealing the function of cytosine methylation as a highly regulated and complex state-not simply a static, inherited signature or binary on-off switch. Alongside these fundamental discoveries, clinical studies over the past decade have revealed the dramatic consequences of aberrant DNA demethylation. In this review we discuss DNA demethylation and deamination in the context of 5-methylcytosine as critical processes for physiological and physiopathological transitions within three states-development, immune maturation, and oncogenic transformation; and we describe the expanding role of DNA demethylating drugs as therapeutic agents in cancer.
Collapse
Affiliation(s)
- Rahul Prasad
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Timothy J. Yen
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| |
Collapse
|
7
|
Pol β gap filling, DNA ligation and substrate-product channeling during base excision repair opposite oxidized 5-methylcytosine modifications. DNA Repair (Amst) 2020; 95:102945. [PMID: 32853828 DOI: 10.1016/j.dnarep.2020.102945] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/07/2020] [Accepted: 07/24/2020] [Indexed: 12/13/2022]
Abstract
DNA methylation on cytosine in CpG islands generates 5-methylcytosine (5mC), and further modification of 5mC can result in the oxidized variants 5-hydroxymethyl (5hmC), 5-formyl (5fC), and 5-carboxy (5caC). Base excision repair (BER) is crucial for both genome maintenance and active DNA demethylation of modified cytosine products and involves substrate-product channeling from nucleotide insertion by DNA polymerase (pol) β to the subsequent ligation step. Here, we report that, in contrast to the pol β mismatch insertion products (dCTP, dATP, and dTTP), the nicked products after pol β dGTP insertion can be ligated by DNA ligase I or DNA ligase III/XRCC1 complex when a 5mC oxidation modification is present opposite in the template position in vitro. A Pol β K280A mutation, which perturbates the stabilization of these base modifications within the active site, hinders the BER ligases. Moreover, the nicked repair intermediates that mimic pol β mismatch insertion products, i.e., with 3'-preinserted dGMP or dTMP opposite templating 5hmC, 5fC or 5caC, can be efficiently ligated, whereas preinserted 3'-dAMP or dCMP mismatches result in failed ligation reactions. These findings herein contribute to our understanding of the insertion tendencies of pol β opposite different cytosine base forms, the ligation properties of DNA ligase I and DNA ligase III/XRCC1 complex in the context of gapped and nicked damage-containing repair intermediates, and the efficiency and fidelity of substrate channeling during the final steps of BER in situations involving oxidative 5mC base modifications in the template strand.
Collapse
|
8
|
Schneider M, Trummer C, Stengl A, Zhang P, Szwagierczak A, Cardoso MC, Leonhardt H, Bauer C, Antes I. Systematic analysis of the binding behaviour of UHRF1 towards different methyl- and carboxylcytosine modification patterns at CpG dyads. PLoS One 2020; 15:e0229144. [PMID: 32084194 PMCID: PMC7034832 DOI: 10.1371/journal.pone.0229144] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/30/2020] [Indexed: 01/24/2023] Open
Abstract
The multi-domain protein UHRF1 is essential for DNA methylation maintenance and binds DNA via a base-flipping mechanism with a preference for hemi-methylated CpG sites. We investigated its binding to hemi- and symmetrically modified DNA containing either 5-methylcytosine (mC), 5-hydroxymethylcytosine (hmC), 5-formylcytosine (fC), or 5-carboxylcytosine (caC). Our experimental results indicate that UHRF1 binds symmetrically carboxylated and hybrid methylated/carboxylated CpG dyads in addition to its previously reported substrates. Complementary molecular dynamics simulations provide a possible mechanistic explanation of how the protein could differentiate between modification patterns. First, we observe different local binding modes in the nucleotide binding pocket as well as the protein's NKR finger. Second, both DNA modification sites are coupled through key residues within the NKR finger, suggesting a communication pathway affecting protein-DNA binding for carboxylcytosine modifications. Our results suggest a possible additional function of the hemi-methylation reader UHRF1 through binding of carboxylated CpG sites. This opens the possibility of new biological roles of UHRF1 beyond DNA methylation maintenance and of oxidised methylcytosine derivates in epigenetic regulation.
Collapse
Affiliation(s)
- Markus Schneider
- Center for Integrated Protein Science Munich at the TUM School of Life Sciences, Technische Universität München, Freising, Germany
| | - Carina Trummer
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Andreas Stengl
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Peng Zhang
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
- Cell Biology and Epigenetics at the Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Aleksandra Szwagierczak
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - M. Cristina Cardoso
- Cell Biology and Epigenetics at the Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Christina Bauer
- Center for Integrated Protein Science Munich at the Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Iris Antes
- Center for Integrated Protein Science Munich at the TUM School of Life Sciences, Technische Universität München, Freising, Germany
- * E-mail:
| |
Collapse
|
9
|
Martinez-Redondo P, Izpisua Belmonte JC. Tailored chromatin modulation to promote tissue regeneration. Semin Cell Dev Biol 2019; 97:3-15. [PMID: 31028854 DOI: 10.1016/j.semcdb.2019.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/22/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022]
Abstract
Epigenetic regulation of gene expression is fundamental in the maintenance of cellular identity and the regulation of cellular plasticity during tissue repair. In fact, epigenetic modulation is associated with the processes of cellular de-differentiation, proliferation, and re-differentiation that takes place during tissue regeneration. In here we explore the epigenetic events that coordinate tissue repair in lower vertebrates with high regenerative capacity, and in mammalian adult stem cells, which are responsible for the homeostasis maintenance of most of our tissues. Finally we summarize promising CRISPR-based editing technologies developed during the last years, which look as promising tools to not only study but also promote specific events during tissue regeneration.
Collapse
Affiliation(s)
- Paloma Martinez-Redondo
- Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, United States
| | - Juan Carlos Izpisua Belmonte
- Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, United States.
| |
Collapse
|
10
|
Howard MJ, Foley KG, Shock DD, Batra VK, Wilson SH. Molecular basis for the faithful replication of 5-methylcytosine and its oxidized forms by DNA polymerase β. J Biol Chem 2019; 294:7194-7201. [PMID: 30885943 DOI: 10.1074/jbc.ra118.006809] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/13/2019] [Indexed: 01/10/2023] Open
Abstract
DNA methylation is an epigenetic mark that regulates gene expression in mammals. One method of methylation removal is through ten-eleven translocation-catalyzed oxidation and the base excision repair pathway. The iterative oxidation of 5-methylcytosine catalyzed by ten-eleven translocation enzymes produces three oxidized forms of cytosine: 5-hydroxmethylcytosine, 5-formylcytosine, and 5-carboxycytosine. The effect these modifications have on the efficiency and fidelity of the base excision repair pathway during the repair of opposing base damage, and in particular DNA polymerization, remains to be elucidated. Using kinetic assays, we show that the catalytic efficiency for the incorporation of dGTP catalyzed by human DNA polymerase β is not affected when 5-methylcytosine, 5-hydroxmethylcytosine, and 5-formylcytosine are in the DNA template. In contrast, the catalytic efficiency of dGTP insertion decreases ∼20-fold when 5-carboxycytosine is in the templating position, as compared with unmodified cytosine. However, DNA polymerase fidelity is unaltered when these modifications are in the templating position. Structural analysis reveals that the methyl, hydroxymethyl, and formyl modifications are easily accommodated within the polymerase active site. However, to accommodate the carboxyl modification, the phosphate backbone on the templating nucleotide shifts ∼2.5 Å to avoid a potential steric/repulsive clash. This altered conformation is stabilized by lysine 280, which makes a direct interaction with the carboxyl modification and the phosphate backbone of the templating strand. This work provides the molecular basis for the accommodation of epigenetic base modifications in a polymerase active site and suggests that these modifications are not mutagenically copied during base excision repair.
Collapse
Affiliation(s)
- Michael J Howard
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - K Grace Foley
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - David D Shock
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Vinod K Batra
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Samuel H Wilson
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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: 13] [Impact Index Per Article: 1.9] [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.
Collapse
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
| |
Collapse
|
13
|
Costello KR, Schones DE. Chromatin modifications in metabolic disease: Potential mediators of long-term disease risk. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2018; 10:e1416. [PMID: 29369528 PMCID: PMC6002879 DOI: 10.1002/wsbm.1416] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/30/2017] [Accepted: 12/08/2017] [Indexed: 12/29/2022]
Abstract
Metabolic diseases such as obesity and diabetes are complex diseases resulting from multiple genetic and environmental factors, such as diet and activity levels. These factors are well known contributors to the development of metabolic diseases. One manner by which environmental factors can influence metabolic disease progression is through modifications to chromatin. These modifications can lead to altered gene regulatory programs, which alters disease risk. Furthermore, there is evidence that parents exposed to environmental factors can influence the metabolic health of offspring, especially if exposures are during intrauterine growth periods. In this review, we outline the evidence that chromatin modifications are associated with metabolic diseases, including diabetes and obesity. We also consider evidence that these chromatin modifications can lead to long-term disease risk and contribute to disease risk for future generations. This article is categorized under: Biological Mechanisms > Metabolism Developmental Biology > Developmental Processes in Health and Disease Physiology > Organismal Responses to Environment.
Collapse
Affiliation(s)
- Kevin R. Costello
- Department of Diabetes Complications and MetabolismIrell & Manella Graduate School, City of HopeDuarteCalifornia
| | - Dustin E. Schones
- Department of Diabetes Complications and MetabolismIrell & Manella Graduate School, City of HopeDuarteCalifornia
| |
Collapse
|
14
|
Tomkova M, Schuster-Böckler B. DNA Modifications: Naturally More Error Prone? Trends Genet 2018; 34:627-638. [PMID: 29853204 DOI: 10.1016/j.tig.2018.04.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/22/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
Abstract
Epigenetic DNA modifications are essential for normal cell function in vertebrates, but they can also be hotspots of mutagenesis. Methylcytosine in particular has long been known to be less stable than other nucleotides and spontaneously deaminates to thymine. Beyond this well-established phenomenon, however, the influence of epigenetic marks on mutagenesis has recently become an active field of investigation. In this review, we summarize current knowledge of the interactions between different DNA modifications and other mutagenic processes. External mutagens, such as UV light or smoking carcinogens, affect modified cytosines differently from unmodified ones, and modified cytosine can in some cases be protective rather than mutagenic. Notably, cell-intrinsic processes, such as DNA replication, also appear to influence the mutagenesis of modified cytosines. Altogether, evidence is accumulating to show that epigenetic changes have a profound influence on tissue-specific mutation accumulation.
Collapse
Affiliation(s)
- Marketa Tomkova
- Ludwig Cancer Research Oxford, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Benjamin Schuster-Böckler
- Ludwig Cancer Research Oxford, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
| |
Collapse
|
15
|
Hardwick JS, Lane AN, Brown T. Epigenetic Modifications of Cytosine: Biophysical Properties, Regulation, and Function in Mammalian DNA. Bioessays 2018; 40. [DOI: 10.1002/bies.201700199] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/13/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Jack S. Hardwick
- Chemistry Research Laboratory; Department of Chemistry; University of Oxford; 12 Mansfield Road Oxford OX1 3TA UK
| | - Andrew N. Lane
- Department of Toxicology and Cancer Biology; University of Kentucky; 789 S. Limestone St. Lexington KY 40536 USA
| | - Tom Brown
- Chemistry Research Laboratory; Department of Chemistry; University of Oxford; 12 Mansfield Road Oxford OX1 3TA UK
| |
Collapse
|
16
|
Olinski R, Gackowski D, Cooke MS. Endogenously generated DNA nucleobase modifications source, and significance as possible biomarkers of malignant transformation risk, and role in anticancer therapy. Biochim Biophys Acta Rev Cancer 2017; 1869:29-41. [PMID: 29128527 DOI: 10.1016/j.bbcan.2017.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 01/26/2023]
Abstract
The DNA of all living cells undergoes continuous structural and chemical alteration, which may be derived from exogenous sources, or endogenous, metabolic pathways, such as cellular respiration, replication and DNA demethylation. It has been estimated that approximately 70,000 DNA lesions may be generated per day in a single cell, and this has been linked to a wide variety of diseases, including cancer. However, it is puzzling why potentially mutagenic DNA modifications, occurring at a similar level in different organs/tissue, may lead to organ/tissue specific cancers, or indeed non-malignant disease - what is the basis for this differential response? We suggest that it is perhaps the precise location of damage, within the genome, that is a key factor. Finally, we draw attention to the requirement for reliable methods for identification and quantification of DNA adducts/modifications, and stress the need for these assays to be fully validated. Once these prerequisites are satisfied, measurement of DNA modifications may be helpful as a clinical parameter for treatment monitoring, risk group identification and development of prevention strategies.
Collapse
Affiliation(s)
- Ryszard Olinski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-095 Bydgoszcz, Poland.
| | - Daniel Gackowski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-095 Bydgoszcz, Poland
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Environmental Health Sciences, Florida International University, Modesto A. Maidique Campus, AHC5 355 11200 SW 8th Street, Miami, FL 33199, United States; Biomolecular Sciences Institute, Florida International University, United States
| |
Collapse
|
17
|
DNA mismatch repair and its many roles in eukaryotic cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:174-187. [PMID: 28927527 DOI: 10.1016/j.mrrev.2017.07.001] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/01/2017] [Accepted: 07/06/2017] [Indexed: 02/06/2023]
Abstract
DNA mismatch repair (MMR) is an important DNA repair pathway that plays critical roles in DNA replication fidelity, mutation avoidance and genome stability, all of which contribute significantly to the viability of cells and organisms. MMR is widely-used as a diagnostic biomarker for human cancers in the clinic, and as a biomarker of cancer susceptibility in animal model systems. Prokaryotic MMR is well-characterized at the molecular and mechanistic level; however, MMR is considerably more complex in eukaryotic cells than in prokaryotic cells, and in recent years, it has become evident that MMR plays novel roles in eukaryotic cells, several of which are not yet well-defined or understood. Many MMR-deficient human cancer cells lack mutations in known human MMR genes, which strongly suggests that essential eukaryotic MMR components/cofactors remain unidentified and uncharacterized. Furthermore, the mechanism by which the eukaryotic MMR machinery discriminates between the parental (template) and the daughter (nascent) DNA strand is incompletely understood and how cells choose between the EXO1-dependent and the EXO1-independent subpathways of MMR is not known. This review summarizes recent literature on eukaryotic MMR, with emphasis on the diverse cellular roles of eukaryotic MMR proteins, the mechanism of strand discrimination and cross-talk/interactions between and co-regulation of MMR and other DNA repair pathways in eukaryotic cells. The main conclusion of the review is that MMR proteins contribute to genome stability through their ability to recognize and promote an appropriate cellular response to aberrant DNA structures, especially when they arise during DNA replication. Although the molecular mechanism of MMR in the eukaryotic cell is still not completely understood, increased used of single-molecule analyses in the future may yield new insight into these unsolved questions.
Collapse
|
18
|
Pan F, Wingo TS, Zhao Z, Gao R, Makishima H, Qu G, Lin L, Yu M, Ortega JR, Wang J, Nazha A, Chen L, Yao B, Liu C, Chen S, Weeks O, Ni H, Phillips BL, Huang S, Wang J, He C, Li GM, Radivoyevitch T, Aifantis I, Maciejewski JP, Yang FC, Jin P, Xu M. Tet2 loss leads to hypermutagenicity in haematopoietic stem/progenitor cells. Nat Commun 2017; 8:15102. [PMID: 28440315 PMCID: PMC5414116 DOI: 10.1038/ncomms15102] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 02/27/2017] [Indexed: 12/12/2022] Open
Abstract
TET2 is a dioxygenase that catalyses multiple steps of 5-methylcytosine oxidation. Although TET2 mutations frequently occur in various types of haematological malignancies, the mechanism by which they increase risk for these cancers remains poorly understood. Here we show that Tet2-/- mice develop spontaneous myeloid, T- and B-cell malignancies after long latencies. Exome sequencing of Tet2-/- tumours reveals accumulation of numerous mutations, including Apc, Nf1, Flt3, Cbl, Notch1 and Mll2, which are recurrently deleted/mutated in human haematological malignancies. Single-cell-targeted sequencing of wild-type and premalignant Tet2-/- Lin-c-Kit+ cells shows higher mutation frequencies in Tet2-/- cells. We further show that the increased mutational burden is particularly high at genomic sites that gained 5-hydroxymethylcytosine, where TET2 normally binds. Furthermore, TET2-mutated myeloid malignancy patients have significantly more mutational events than patients with wild-type TET2. Thus, Tet2 loss leads to hypermutagenicity in haematopoietic stem/progenitor cells, suggesting a novel TET2 loss-mediated mechanism of haematological malignancy pathogenesis.
Collapse
Affiliation(s)
- Feng Pan
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA.,Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.,Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA
| | - Thomas S Wingo
- Departments of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307, USA.,Neurology, Emory University School of Medicine, Atlanta, Georgia 30307, USA.,Division of Neurology, Department of Veterans Affairs Medical Center, Atlanta, Georgia 30033, USA
| | - Zhigang Zhao
- Department of Hematology and Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Rui Gao
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA
| | - Hideki Makishima
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | - Guangbo Qu
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA.,Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Li Lin
- Departments of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307, USA
| | - Miao Yu
- Department of Chemistry and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois 60637, USA
| | - Janice R Ortega
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA
| | - Jiapeng Wang
- Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Aziz Nazha
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | - Li Chen
- Departments of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307, USA
| | - Bing Yao
- Departments of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307, USA
| | - Can Liu
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA
| | - Shi Chen
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA
| | - Ophelia Weeks
- Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA
| | - Hongyu Ni
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Brittany Lynn Phillips
- Department of Biochemistry and Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30307, USA
| | - Suming Huang
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32611, USA
| | - Jianlong Wang
- Department of Developmental and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Chuan He
- Department of Chemistry and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois 60637, USA
| | - Guo-Min Li
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA
| | - Tomas Radivoyevitch
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | - Iannis Aifantis
- Howard Hughes Medical Institute and Department of Pathology, NYU School of Medicine, New York, New York 10016, USA.,NYU Cancer Institute and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, New York 10016, USA
| | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
| | - Feng-Chun Yang
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA.,Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Peng Jin
- Departments of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307, USA
| | - Mingjiang Xu
- Department of Biochemistry and Molecular Biology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1011 NW 15th Street, Room 411, Gautier Building, MC R629, Miami, Florida 33136, USA.,Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| |
Collapse
|
19
|
Cimmino L, Aifantis I. Alternative roles for oxidized mCs and TETs. Curr Opin Genet Dev 2016; 42:1-7. [PMID: 27939598 DOI: 10.1016/j.gde.2016.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 11/15/2016] [Indexed: 01/09/2023]
Abstract
Ten-eleven-translocation (TET) proteins oxidize 5-methylcytosine (5mC) to form stable or transient modifications (oxi-mCs) in the mammalian genome. Genome-wide mapping and protein interaction studies have shown that 5mC and oxi-mCs have unique distribution patterns and alternative roles in gene expression. In addition, oxi-mCs may interact with specific chromatin regulators, transcription factors and DNA repair proteins to maintain genomic integrity or alter DNA replication and transcriptional elongation rates. In this review we will discuss recent advances in our understanding of how TETs and 5hmC exert their epigenetic function as tumor suppressors by playing alternative roles in transcriptional regulation and genomic stability.
Collapse
Affiliation(s)
- Luisa Cimmino
- Department of Pathology, NYU School of Medicine, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
| | - Iannis Aifantis
- Department of Pathology, NYU School of Medicine, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| |
Collapse
|
20
|
Modrzejewska M, Gawronski M, Skonieczna M, Zarakowska E, Starczak M, Foksinski M, Rzeszowska-Wolny J, Gackowski D, Olinski R. Vitamin C enhances substantially formation of 5-hydroxymethyluracil in cellular DNA. Free Radic Biol Med 2016; 101:378-383. [PMID: 27833031 DOI: 10.1016/j.freeradbiomed.2016.10.535] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/14/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022]
Abstract
The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5-Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5-hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5-hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions.
Collapse
Affiliation(s)
- Martyna Modrzejewska
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Maciej Gawronski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Magdalena Skonieczna
- Biosystems Group, Institute of Automatic Control, Faculty of Automatics, Electronics, and Informatics, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland.
| | - Ewelina Zarakowska
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Marta Starczak
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Marek Foksinski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Joanna Rzeszowska-Wolny
- Biosystems Group, Institute of Automatic Control, Faculty of Automatics, Electronics, and Informatics, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland.
| | - Daniel Gackowski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| | - Ryszard Olinski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85-092 Bydgoszcz, Poland.
| |
Collapse
|
21
|
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: 110] [Impact Index Per Article: 12.2] [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.
Collapse
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
| |
Collapse
|
22
|
Grin I, Ishchenko AA. An interplay of the base excision repair and mismatch repair pathways in active DNA demethylation. Nucleic Acids Res 2016; 44:3713-27. [PMID: 26843430 PMCID: PMC4856981 DOI: 10.1093/nar/gkw059] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 01/22/2016] [Indexed: 01/02/2023] Open
Abstract
Active DNA demethylation (ADDM) in mammals occurs via hydroxylation of 5-methylcytosine (5mC) by TET and/or deamination by AID/APOBEC family enzymes. The resulting 5mC derivatives are removed through the base excision repair (BER) pathway. At present, it is unclear how the cell manages to eliminate closely spaced 5mC residues whilst avoiding generation of toxic BER intermediates and whether alternative DNA repair pathways participate in ADDM. It has been shown that non-canonical DNA mismatch repair (ncMMR) can remove both alkylated and oxidized nucleotides from DNA. Here, a phagemid DNA containing oxidative base lesions and methylated sites are used to examine the involvement of various DNA repair pathways in ADDM in murine and human cell-free extracts. We demonstrate that, in addition to short-patch BER, 5-hydroxymethyluracil and uracil mispaired with guanine can be processed by ncMMR and long-patch BER with concomitant removal of distant 5mC residues. Furthermore, the presence of multiple mispairs in the same MMR nick/mismatch recognition region together with BER-mediated nick formation promotes proficient ncMMR resulting in the reactivation of an epigenetically silenced reporter gene in murine cells. These findings suggest cooperation between BER and ncMMR in the removal of multiple mismatches that might occur in mammalian cells during ADDM.
Collapse
Affiliation(s)
- Inga Grin
- Laboratoire «Stabilité Génétique et Oncogenèse» CNRS, UMR 8200, Univ. Paris-Sud, Université Paris-Saclay, Equipe Labellisée Ligue Contre le Cancer, F-94805 Villejuif, France Gustave Roussy Cancer Campus, F-94805 Villejuif, France SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, Novosibirsk 630090, Russia Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Laboratoire «Stabilité Génétique et Oncogenèse» CNRS, UMR 8200, Univ. Paris-Sud, Université Paris-Saclay, Equipe Labellisée Ligue Contre le Cancer, F-94805 Villejuif, France Gustave Roussy Cancer Campus, F-94805 Villejuif, France
| |
Collapse
|
23
|
Gackowski D, Zarakowska E, Starczak M, Modrzejewska M, Olinski R. Tissue-Specific Differences in DNA Modifications (5-Hydroxymethylcytosine, 5-Formylcytosine, 5-Carboxylcytosine and 5-Hydroxymethyluracil) and Their Interrelationships. PLoS One 2015; 10:e0144859. [PMID: 26660343 PMCID: PMC4682766 DOI: 10.1371/journal.pone.0144859] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/23/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Replication-independent active/enzymatic demethylation may be an important process in the functioning of somatic cells. The most plausible mechanisms of active 5-methylcytosine demethylation, leading to activation of previously silenced genes, involve ten-eleven translocation (TET) proteins that participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine which can be further oxidized to 5-formylcytosine and 5-carboxylcytosine. Recently, 5-hydroxymethylcytosine was demonstrated to be a relatively stable modification, and the previously observed substantial differences in the level of this modification in various murine tissues were shown to depend mostly on cell proliferation rate. Some experimental evidence supports the hypothesis that 5-hydroxymethyluracil may be also generated by TET enzymes and has epigenetic functions. RESULTS Using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with tandem mass spectrometry, we have analyzed, for the first time, all the products of active DNA demethylation pathway: 5-methyl-2'-deoxycytidine, 5-hydroxymethyl-2'-deoxycytidine, 5-formyl-2'-deoxycytidine and 5-carboxyl-2'-deoxycytidine, as well as 5-hydroxymethyl-2'-deoxyuridine, in DNA isolated from various rat and porcine tissues. A strong significant inverse linear correlation was found between the proliferation rate of cells and the global level of 5-hydroxymethyl-2'-deoxycytidine in both porcine (R2 = 0.88) and rat tissues (R2 = 0.83); no such relationship was observed for 5-formyl-2'-deoxycytidine and 5-carboxyl-2'-deoxycytidine. Moreover, a substrate-product correlation was demonstrated for the two consecutive steps of iterative oxidation pathway: between 5-hydroxymethyl-2'-deoxycytidine and its product 5-formyl-2'-deoxycytidine, as well as between 5-formyl-2'-deoxycytidine and 5-carboxyl-2'-deoxycytidine (R2 = 0.60 and R2 = 0.71, respectively). CONCLUSIONS Good correlations within the substrate-product sets of iterative oxidation pathway may suggest that a part of 5-formyl-2'-deoxycytidine and/or 5-carboxyl-2'-deoxycytidine can be directly linked to a small portion of 5-hydroxymethyl-2'-deoxycytidine which defines the active demethylation process.
Collapse
Affiliation(s)
- Daniel Gackowski
- Department of Clinical Biochemistry, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
| | - Ewelina Zarakowska
- Department of Clinical Biochemistry, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
| | - Marta Starczak
- Department of Clinical Biochemistry, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
| | - Martyna Modrzejewska
- Department of Clinical Biochemistry, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
| | - Ryszard Olinski
- Department of Clinical Biochemistry, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
- * E-mail:
| |
Collapse
|
24
|
Effects of Tet-mediated oxidation products of 5-methylcytosine on DNA transcription in vitro and in mammalian cells. Sci Rep 2014; 4:7052. [PMID: 25394478 PMCID: PMC4231326 DOI: 10.1038/srep07052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/24/2014] [Indexed: 12/21/2022] Open
Abstract
5-methylcytosine (5-mC) is a well-characterized epigenetic regulator in mammals. Recent studies showed that Ten-eleven translocation (Tet) proteins can catalyze the stepwise oxidation of 5-mC to produce 5-hydroxymethylcytosine (5-HmC), 5-formylcytosine (5-FoC) and 5-carboxylcytosine (5-CaC). The exciting discovery of these novel cytosine modifications has stimulated substantial research interests about their roles in epigenetic regulation. Here we systematically examined the effects of the oxidized 5-mC derivatives on the efficiency and fidelity of DNA transcription using a recently developed competitive transcription and adduct bypass assay. Our results showed that, when located on the transcribed strand, 5-FoC and 5-CaC exhibited marginal mutagenic and modest inhibitory effects on DNA transcription mediated by single-subunit T7 RNA polymerase or multi-subunit human RNA polymerase II in vitro and in human cells. 5-HmC displayed relatively milder blocking effects on transcription, and no mutant transcript could be detectable for 5-HmC in vitro or in cells. The lack of considerable mutagenic effects of the oxidized 5-mC derivatives on transcription was in agreement with their functions in epigenetic regulation. The modest blocking effects on transcription suggested that 5-FoC and 5-CaC may function in transcriptional regulation. These findings provided new evidence for the potential functional interplay between cytosine methylation status and transcription.
Collapse
|
25
|
Supek F, Lehner B, Hajkova P, Warnecke T. Hydroxymethylated cytosines are associated with elevated C to G transversion rates. PLoS Genet 2014; 10:e1004585. [PMID: 25211471 PMCID: PMC4161303 DOI: 10.1371/journal.pgen.1004585] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/07/2014] [Indexed: 11/23/2022] Open
Abstract
It has long been known that methylated cytosines deaminate at higher rates than unmodified cytosines and constitute mutational hotspots in mammalian genomes. The repertoire of naturally occurring cytosine modifications, however, extends beyond 5-methylcytosine to include its oxidation derivatives, notably 5-hydroxymethylcytosine. The effects of these modifications on sequence evolution are unknown. Here, we combine base-resolution maps of methyl- and hydroxymethylcytosine in human and mouse with population genomic, divergence and somatic mutation data to show that hydroxymethylated and methylated cytosines show distinct patterns of variation and evolution. Surprisingly, hydroxymethylated sites are consistently associated with elevated C to G transversion rates at the level of segregating polymorphisms, fixed substitutions, and somatic mutations in tumors. Controlling for multiple potential confounders, we find derived C to G SNPs to be 1.43-fold (1.22-fold) more common at hydroxymethylated sites compared to methylated sites in human (mouse). Increased C to G rates are evident across diverse functional and sequence contexts and, in cancer genomes, correlate with the expression of Tet enzymes and specific components of the mismatch repair pathway (MSH2, MSH6, and MBD4). Based on these and other observations we suggest that hydroxymethylation is associated with a distinct mutational burden and that the mismatch repair pathway is implicated in causing elevated transversion rates at hydroxymethylated cytosines. Most cytosines that occur in a CpG context in mammalian genomes are methylated. Methylation has important functional consequences in the cell but also affects genome evolution. Notably, methylated cytosines are prone to deaminate and constitute mutational hotspots in mammalian genomes. Recently, a series of other modifications, derived from the oxidation of methylated cytosines, was shown to exist in various mammalian cell types including embryonic stem cells. The most abundant of these modifications is 5-hydroxymethylcytosine. In this work, we ask whether methylated and hydroxymethylated cytosines are subject to the same mutational biases or lead to distinct patterns of genome evolution. To do so, we examine differences between individuals, between species, and between normal and cancer tissues alongside high-resolution maps of DNA methylation and hydroxymethylation in the human and mouse genomes. Unexpectedly, we find that hydroxymethylated cytosines are associated with more cytosine to guanine changes in both human and mouse populations, in closely related species, and in the context of somatic evolution in tumors. Based on multiple lines of evidence, we suggest that the different patterns of sequence evolution at methylated and hydroxymethylated sites are owing to differences in how these sites are handled by the DNA repair machinery.
Collapse
Affiliation(s)
- Fran Supek
- EMBL-CRG Systems Biology Unit, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Division of Electronics, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Ben Lehner
- EMBL-CRG Systems Biology Unit, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Centre for Genomic Regulation (CRG) and UPF, Barcelona, Spain
| | - Petra Hajkova
- Reprogramming and Chromatin Group, MRC Clinical Sciences Centre, Imperial College, Hammersmith Campus, London, United Kingdom
| | - Tobias Warnecke
- Molecular Systems Group, MRC Clinical Sciences Centre, Imperial College, Hammersmith Campus, London, United Kingdom
- * E-mail:
| |
Collapse
|