1
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Morledge-Hampton B, Kalyanaraman A, Wyrick JJ. Analysis of cytosine deamination events in excision repair sequencing reads reveals mechanisms of incision site selection in NER. Nucleic Acids Res 2024; 52:1720-1735. [PMID: 38109317 PMCID: PMC10899786 DOI: 10.1093/nar/gkad1195] [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: 05/17/2023] [Revised: 11/28/2023] [Accepted: 12/01/2023] [Indexed: 12/20/2023] Open
Abstract
Nucleotide excision repair (NER) removes helix-distorting DNA lesions and is therefore critical for genome stability. During NER, DNA is unwound on either side of the lesion and excised, but the rules governing incision site selection, particularly in eukaryotic cells, are unclear. Excision repair-sequencing (XR-seq) sequences excised NER fragments, but analysis has been limited because the lesion location is unknown. Here, we exploit accelerated cytosine deamination rates in UV-induced CPD (cyclobutane pyrimidine dimer) lesions to precisely map their locations at C to T mismatches in XR-seq reads, revealing general and species-specific patterns of incision site selection during NER. Our data indicate that the 5' incision site occurs preferentially in HYV (i.e. not G; C/T; not T) sequence motifs, a pattern that can be explained by sequence preferences of the XPF-ERCC1 endonuclease. In contrast, the 3' incision site does not show strong sequence preferences, once truncated reads arising from mispriming events are excluded. Instead, the 3' incision is partially determined by the 5' incision site distance, indicating that the two incision events are coupled. Finally, our data reveal unique and coupled NER incision patterns at nucleosome boundaries. These findings reveal key principles governing NER incision site selection in eukaryotic cells.
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Affiliation(s)
| | - Ananth Kalyanaraman
- School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164, USA
| | - John J Wyrick
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
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2
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Duan M, Song S, Wasserman H, Lee PH, Liu KJ, Gordân R, He Y, Mao P. High UV damage and low repair, but not cytosine deamination, stimulate mutation hotspots at ETS binding sites in melanoma. Proc Natl Acad Sci U S A 2024; 121:e2310854121. [PMID: 38241433 PMCID: PMC10823218 DOI: 10.1073/pnas.2310854121] [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: 06/27/2023] [Accepted: 11/20/2023] [Indexed: 01/21/2024] Open
Abstract
Noncoding mutation hotspots have been identified in melanoma and many of them occur at the binding sites of E26 transformation-specific (ETS) proteins; however, their formation mechanism and functional impacts are not fully understood. Here, we used UV (Ultraviolet) damage sequencing data and analyzed cyclobutane pyrimidine dimer (CPD) formation, DNA repair, and CPD deamination in human cells at single-nucleotide resolution. Our data show prominent CPD hotspots immediately after UV irradiation at ETS binding sites, particularly at sites with a conserved TTCCGG motif, which correlate with mutation hotspots identified in cutaneous melanoma. Additionally, CPDs are repaired slower at ETS binding sites than in flanking DNA. Cytosine deamination in CPDs to uracil is suggested as an important step for UV mutagenesis. However, we found that CPD deamination is significantly suppressed at ETS binding sites, particularly for the CPD hotspot on the 5' side of the ETS motif, arguing against a role for CPD deamination in promoting ETS-associated UV mutations. Finally, we analyzed a subset of frequently mutated promoters, including the ribosomal protein genes RPL13A and RPS20, and found that mutations in the ETS motif can significantly reduce the promoter activity. Thus, our data identify high UV damage and low repair, but not CPD deamination, as the main mechanism for ETS-associated mutations in melanoma and uncover important roles of often-overlooked mutation hotspots in perturbing gene transcription.
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Affiliation(s)
- Mingrui Duan
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM87131
| | - Shenghan Song
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM87131
- Translational Informatics Division, Department of Internal Medicine, University of New Mexico, Albuquerque, NM87131
| | - Hana Wasserman
- Program in Computational Biology and Bioinformatics, Department of Biostatistics and Bioinformatics, Duke University, Durham, NC27708
| | - Po-Hsuen Lee
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM87131
| | - Ke Jian Liu
- Department of Pathology, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY11794-7263
| | - Raluca Gordân
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC27708
- Department of Computer Science, Duke University, Durham, NC27708
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC27708
| | - Yi He
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM87131
- Translational Informatics Division, Department of Internal Medicine, University of New Mexico, Albuquerque, NM87131
| | - Peng Mao
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM87131
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3
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Menck CFM, Galhardo RS, Quinet A. The accurate bypass of pyrimidine dimers by DNA polymerase eta contributes to ultraviolet-induced mutagenesis. Mutat Res 2024; 828:111840. [PMID: 37984186 DOI: 10.1016/j.mrfmmm.2023.111840] [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: 06/10/2023] [Revised: 10/23/2023] [Accepted: 11/02/2023] [Indexed: 11/22/2023]
Abstract
Human xeroderma pigmentosum variant (XP-V) patients are mutated in the POLH gene, responsible for encoding the translesion synthesis (TLS) DNA polymerase eta (Pol eta). These patients suffer from a high frequency of skin tumors. Despite several decades of research, studies on Pol eta still offer an intriguing paradox: How does this error-prone polymerase suppress mutations? This review examines recent evidence suggesting that cyclobutane pyrimidine dimers (CPDs) are instructional for Pol eta. Consequently, it can accurately replicate these lesions, and the mutagenic effects induced by UV radiation stem from the deamination of C-containing CPDs. In this model, the deamination of C (forming a U) within CPDs leads to the correct insertion of an A opposite to the deaminated C (or U)-containing dimers. This intricate process results in C>T transitions, which represent the most prevalent mutations detected in skin cancers. Finally, the delayed replication in XP-V cells amplifies the process of C-deamination in CPDs and increases the burden of C>T mutations prevalent in XP-V tumors through the activity of backup TLS polymerases.
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Affiliation(s)
- C F M Menck
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil.
| | - R S Galhardo
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - A Quinet
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, F-92265 Fontenay-aux-Roses, France; Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, F-92265 Fontenay-aux-Roses, France
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4
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Sethi S, Takashima Y, Nakamura S, Wan L, Honda N, Fujimoto K. Acceleration of the Deamination of Cytosine through Photo-Crosslinking. Curr Issues Mol Biol 2023; 45:4687-4700. [PMID: 37367047 DOI: 10.3390/cimb45060298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/18/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Herein, we report the major factor for deamination reaction rate acceleration, i.e., hydrophilicity, by using various 5-substituted target cytosines and by carrying out deamination at high temperatures. Through substitution of the groups at the 5'-position of the cytosine, the effect of hydrophilicity was understood. It was then used to compare the various modifications of the photo-cross-linkable moiety as well as the effect of the counter base of the cytosine to edit both DNA and RNA. Furthermore, we were able to achieve cytosine deamination at 37 °C with a half-life in the order of a few hours.
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Affiliation(s)
- Siddhant Sethi
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
| | - Yasuharu Takashima
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
| | - Shigetaka Nakamura
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
| | - Licheng Wan
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
| | - Nozomi Honda
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
| | - Kenzo Fujimoto
- Bioscience, Biotechnology, and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Asahi-dai 1-1, Ishikawa, Nomi 923-1292, Japan
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5
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Vandenberg BN, Laughery MF, Cordero C, Plummer D, Mitchell D, Kreyenhagen J, Albaqshi F, Brown AJ, Mieczkowski PA, Wyrick JJ, Roberts SA. Contributions of replicative and translesion DNA polymerases to mutagenic bypass of canonical and atypical UV photoproducts. Nat Commun 2023; 14:2576. [PMID: 37142570 PMCID: PMC10160025 DOI: 10.1038/s41467-023-38255-5] [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: 09/13/2022] [Accepted: 04/21/2023] [Indexed: 05/06/2023] Open
Abstract
UV exposure induces a mutation signature of C > T substitutions at dipyrimidines in skin cancers. We recently identified additional UV-induced AC > TT and A > T substitutions that could respectively cause BRAF V600K and V600E oncogenic mutations. The mutagenic bypass mechanism past these atypical lesions, however, is unknown. Here, we whole genome sequenced UV-irradiated yeast and used reversion reporters to delineate the roles of replicative and translesion DNA polymerases in mutagenic bypass of UV-lesions. Our data indicates that yeast DNA polymerase eta (pol η) has varied impact on UV-induced mutations: protecting against C > T substitutions, promoting T > C and AC > TT substitutions, and not impacting A > T substitutions. Surprisingly, deletion rad30Δ increased novel UV-induced C > A substitutions at CA dinucleotides. In contrast, DNA polymerases zeta (pol ζ) and epsilon (pol ε) participated in AC > TT and A > T mutations. These results uncover lesion-specific accurate and mutagenic bypass of UV lesions, which likely contribute to key driver mutations in melanoma.
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Affiliation(s)
- Brittany N Vandenberg
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Marian F Laughery
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Cameron Cordero
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Dalton Plummer
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Debra Mitchell
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Jordan Kreyenhagen
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Fatimah Albaqshi
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Alexander J Brown
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA
| | - Piotr A Mieczkowski
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - John J Wyrick
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA.
| | - Steven A Roberts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA.
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6
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Jin SG, Padron F, Pfeifer GP. UVA Radiation, DNA Damage, and Melanoma. ACS OMEGA 2022; 7:32936-32948. [PMID: 36157735 PMCID: PMC9494637 DOI: 10.1021/acsomega.2c04424] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/30/2022] [Indexed: 05/05/2023]
Abstract
Melanoma is a lethal type of skin tumor that has been linked with sunlight exposure chiefly in fair-skinned human populations. Wavelengths from the sun that can reach the earth's surface include UVA radiation (320-400 nm) and UVB radiation (280-320 nm). UVB effectively induces the formation of dimeric DNA photoproducts, preferentially the cyclobutane pyrimidine dimers (CPDs). The characteristic UVB signature mutations in the form of C to T mutations at dipyrimidine sequences are prevalent in melanoma tumor genomes and have been ascribed to deamination of cytosines within CPDs before DNA polymerase bypass. However, evidence from epidemiological, animal, and other experimental studies also suggest that UVA radiation may participate in melanoma formation. The DNA damage relevant for UVA includes specific types of CPDs at TT sequences and perhaps oxidative DNA damage to guanine, both induced by direct or indirect, photosensitization-mediated chemical and biophysical processes. We summarize the evidence for a potential role of UVA in melanoma and discuss some of the mechanistic pathways of how UVA may induce mutagenesis in melanocytes.
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7
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Sugiyama T, Keinard B, Best G, Sanyal MR. Biochemical and photochemical mechanisms that produce different UV-induced mutation spectra. Mutat Res 2021; 823:111762. [PMID: 34563793 DOI: 10.1016/j.mrfmmm.2021.111762] [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: 06/29/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 11/15/2022]
Abstract
Although UV-induced mutagenesis has been studied extensively, the precise mechanisms that convert UV-induced DNA damage into mutations remain elusive. One well-studied mechanism involves DNA polymerase (Pol) η and ζ, which produces C > T transitions during translesion synthesis (TLS) across pyrimidine dimers. We previously proposed another biochemical mechanism that involves multiple UV-irradiations with incubation in the dark in between. The incubation facilitates spontaneous deamination of cytosine in a pyrimidine dimer, and the subsequent UV irradiation induces photolyase-independent (direct) photoreversal that converts cytosine into monomeric uracil residue. In this paper, we first demonstrate that natural sunlight can induce both mutational processes in vitro. The direct photoreversal was also reproduced by monochromatic UVB at 300 nm. We also demonstrate that post-irradiation incubation in the dark is required for both mutational processes, suggesting that cytosine deamination is required for both the Pol η/ζ-dependent and the photoreversal-dependent mechanisms. Another Y-family polymerase Pol ι also mediated a mutagenic TLS on UV-damaged templates when combined with Pol ζ. The Pol ι-dependent mutations were largely independent of post-irradiation incubation, indicating that cytosine deamination was not essential for this mutational process. Sunlight-exposure also induced C > A transversions which were likely caused by oxidation of guanine residues. Finally, we constructed in vitro mutation spectra in a comparable format to cancer mutation signatures. While both Pol η-dependent and photoreversal-dependent spectra showed high similarities to a cancer signature (SBS7a), Pol ι-dependent mutation spectrum has distinct T > A/C substitutions, which are found in another cancer signature (SBS7d). The Pol ι-dependent T > A/C substitutions were resistant to T4 pyrimidine dimer glycosylase-treatment, suggesting that this mutational process is independent of cis-syn pyrimidine dimers. An updated model about multiple mechanisms of UV-induced mutagenesis is discussed.
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Affiliation(s)
- Tomohiko Sugiyama
- Department of Biological Sciences; Molecular and Cellular Biology Graduate Program, Ohio University, Athens, OH, 45701, USA.
| | | | | | - Mahima R Sanyal
- Department of Biological Sciences; Molecular and Cellular Biology Graduate Program, Ohio University, Athens, OH, 45701, USA
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8
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Jin SG, Pettinga D, Johnson J, Li P, Pfeifer GP. The major mechanism of melanoma mutations is based on deamination of cytosine in pyrimidine dimers as determined by circle damage sequencing. SCIENCE ADVANCES 2021; 7:eabi6508. [PMID: 34330711 PMCID: PMC8324051 DOI: 10.1126/sciadv.abi6508] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/14/2021] [Indexed: 05/22/2023]
Abstract
Sunlight-associated melanomas carry a unique C-to-T mutation signature. UVB radiation induces cyclobutane pyrimidine dimers (CPDs) as the major form of DNA damage, but the mechanism of how CPDs cause mutations is unclear. To map CPDs at single-base resolution genome wide, we developed the circle damage sequencing (circle-damage-seq) method. In human cells, CPDs form preferentially in a tetranucleotide sequence context (5'-Py-T<>Py-T/A), but this alone does not explain the tumor mutation patterns. To test whether mutations arise at CPDs by cytosine deamination, we specifically mapped UVB-induced cytosine-deaminated CPDs. Transcription start sites (TSSs) were protected from CPDs and deaminated CPDs, but both lesions were enriched immediately upstream of the TSS, suggesting a mutation-promoting role of bound transcription factors. Most importantly, the genomic dinucleotide and trinucleotide sequence specificity of deaminated CPDs matched the prominent mutation signature of melanomas. Our data identify the cytosine-deaminated CPD as the leading premutagenic lesion responsible for mutations in melanomas.
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Affiliation(s)
- Seung-Gi Jin
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Dean Pettinga
- Bioinformatics and Biostatistics Core, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Jennifer Johnson
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Peipei Li
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Gerd P Pfeifer
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA.
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9
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Lee JW, Ratnakumar K, Hung KF, Rokunohe D, Kawasumi M. Deciphering UV-induced DNA Damage Responses to Prevent and Treat Skin Cancer. Photochem Photobiol 2020; 96:478-499. [PMID: 32119110 DOI: 10.1111/php.13245] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/11/2020] [Indexed: 12/11/2022]
Abstract
Ultraviolet (UV) radiation is among the most prevalent environmental factors that influence human health and disease. Even 1 h of UV irradiation extensively damages the genome. To cope with resulting deleterious DNA lesions, cells activate a multitude of DNA damage response pathways, including DNA repair. Strikingly, UV-induced DNA damage formation and repair are affected by chromatin state. When cells enter S phase with these lesions, a distinct mutation signature is created via error-prone translesion synthesis. Chronic UV exposure leads to high mutation burden in skin and consequently the development of skin cancer, the most common cancer in the United States. Intriguingly, UV-induced oxidative stress has opposing effects on carcinogenesis. Elucidating the molecular mechanisms of UV-induced DNA damage responses will be useful for preventing and treating skin cancer with greater precision. Excitingly, recent studies have uncovered substantial depth of novel findings regarding the molecular and cellular consequences of UV irradiation. In this review, we will discuss updated mechanisms of UV-induced DNA damage responses including the ATR pathway, which maintains genome integrity following UV irradiation. We will also present current strategies for preventing and treating nonmelanoma skin cancer, including ATR pathway inhibition for prevention and photodynamic therapy for treatment.
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Affiliation(s)
- Jihoon W Lee
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, WA
| | - Kajan Ratnakumar
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, WA
| | - Kai-Feng Hung
- Division of Translational Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Daiki Rokunohe
- Department of Dermatology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Masaoki Kawasumi
- Division of Dermatology, Department of Medicine, University of Washington, Seattle, WA
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10
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Abstract
Ultraviolet (UV) irradiation causes various types of DNA damage, which leads to specific mutations and the emergence of skin cancer in humans, often decades after initial exposure. Different UV wavelengths cause the formation of prominent UV-induced DNA lesions. Most of these lesions are removed by the nucleotide excision repair pathway, which is defective in rare genetic skin disorders referred to as xeroderma pigmentosum. A major role in inducing sunlight-dependent skin cancer mutations is assigned to the cyclobutane pyrimidine dimers (CPDs). In this review, we discuss the mechanisms of UV damage induction, the genomic distribution of this damage, relevant DNA repair mechanisms, the proposed mechanisms of how UV-induced CPDs bring about DNA replication-dependent mutagenicity in mammalian cells, and the strong signature of UV damage and mutagenesis found in skin cancer genomes.
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11
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Sugiyama T, Chen Y. Biochemical reconstitution of UV-induced mutational processes. Nucleic Acids Res 2020; 47:6769-6782. [PMID: 31053851 PMCID: PMC6648339 DOI: 10.1093/nar/gkz335] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/16/2019] [Accepted: 04/24/2019] [Indexed: 02/07/2023] Open
Abstract
We reconstituted two biochemical processes that may contribute to UV-induced mutagenesis in vitro and analysed the mutational profiles in the products. One process is translesion synthesis (TLS) by DNA polymerases (Pol) δ, η and ζ, which creates C>T transitions at pyrimidine dimers by incorporating two dAMPs opposite of the dimers. The other process involves spontaneous deamination of cytosine, producing uracil in pyrimidine dimers, followed by monomerization of the dimers by secondary UV irradiation, and DNA synthesis by Pol δ. The mutational spectrum resulting from deamination without translesion synthesis is similar to a mutational signature found in melanomas, suggesting that cytosine deamination encountered by the replicative polymerase has a prominent role in melanoma development. However, CC>TT dinucleotide substitution, which is also commonly observed in melanomas, was produced almost exclusively by TLS. We propose that both TLS-dependent and deamination-dependent mutational processes are likely involved in UV-induced melanoma development.
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Affiliation(s)
- Tomohiko Sugiyama
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Yizhang Chen
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
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12
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Gontcharov J, Liu L, Pilles BM, Carell T, Schreier WJ, Zinth W. Triplet-Induced Lesion Formation at CpT and TpC Sites in DNA. Chemistry 2019; 25:15164-15172. [PMID: 31538684 PMCID: PMC6899856 DOI: 10.1002/chem.201903573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Indexed: 12/22/2022]
Abstract
UV irradiation induces DNA lesions particularly at dipyrimidine sites. Using time-resolved UV pump (250 nm) and mid-IR probe spectroscopy the triplet pathway of cyclobutane pyrimidine dimer (CPD) formation within TpC and CpT sequences was studied. The triplet state is initially localized at the thymine base but decays with 30 ns under formation of a biradical state extending over both bases of the dipyrimidine. Subsequently this state either decays back to the electronic ground state on the 100 ns time scale or forms a cyclobutane pyrimidine dimer lesion (CPD). Stationary IR spectroscopy and triplet sensitization via 2'-methoxyacetophenone (2-M) in the UVA range shows that the lesions are formed with an efficiency of approximately 1.5 %. Deamination converts the cytosine moiety of the CPD lesions on the time scale of 10 hours into uracil which gives CPD(UpT) and CPD(TpU) lesions in which the coding potential of the initial cytosine base is vanished.
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Affiliation(s)
- Julia Gontcharov
- Lehrstuhl für BioMolekulare OptikFakultät für Physik and Center for Integrated Protein Science Munich CIPSMLudwig-Maximilians-Universität MünchenOettingenstr. 6780538MünchenGermany
| | - Lizhe Liu
- Lehrstuhl für BioMolekulare OptikFakultät für Physik and Center for Integrated Protein Science Munich CIPSMLudwig-Maximilians-Universität MünchenOettingenstr. 6780538MünchenGermany
| | - Bert M. Pilles
- Lehrstuhl für BioMolekulare OptikFakultät für Physik and Center for Integrated Protein Science Munich CIPSMLudwig-Maximilians-Universität MünchenOettingenstr. 6780538MünchenGermany
| | - Thomas Carell
- Center for Integrated Protein Science am Department ChemistryLudwig-Maximilians-Universität MünchenButenandtstraße 5–1381377MünchenGermany
| | - Wolfgang J. Schreier
- Lehrstuhl für BioMolekulare OptikFakultät für Physik and Center for Integrated Protein Science Munich CIPSMLudwig-Maximilians-Universität MünchenOettingenstr. 6780538MünchenGermany
| | - Wolfgang Zinth
- Lehrstuhl für BioMolekulare OptikFakultät für Physik and Center for Integrated Protein Science Munich CIPSMLudwig-Maximilians-Universität MünchenOettingenstr. 6780538MünchenGermany
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13
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Mo X, Preston S, Zaidi MR. Macroenvironment-gene-microenvironment interactions in ultraviolet radiation-induced melanomagenesis. Adv Cancer Res 2019; 144:1-54. [PMID: 31349897 DOI: 10.1016/bs.acr.2019.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cutaneous malignant melanoma is one of the few major cancers that continue to exhibit a positive rate of increase in the developed world. A wealth of epidemiological data has undisputedly implicated ultraviolet radiation (UVR) from sunlight and artificial sources as the major risk factor for melanomagenesis. However, the molecular mechanisms of this cause-and-effect relationship remain murky and understudied. Recent efforts on multiple fronts have brought unprecedented expansion of our knowledge base on this subject and it is now clear that melanoma is caused by a complex interaction between genetic predisposition and environmental exposure, primarily to UVR. Here we provide an overview of the effects of the macroenvironment (UVR) on the skin microenvironment and melanocyte-specific intrinsic (mostly genetic) landscape, which conspire to produce one of the deadliest malignancies.
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Affiliation(s)
- Xuan Mo
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Sarah Preston
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - M Raza Zaidi
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States.
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14
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Ikehata H. Mechanistic considerations on the wavelength-dependent variations of UVR genotoxicity and mutagenesis in skin: the discrimination of UVA-signature from UV-signature mutation. Photochem Photobiol Sci 2018; 17:1861-1871. [PMID: 29850669 DOI: 10.1039/c7pp00360a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ultraviolet radiation (UVR) predominantly induces UV-signature mutations, C → T and CC → TT base substitutions at dipyrimidine sites, in the cellular and skin genome. I observed in our in vivo mutation studies of mouse skin that these UVR-specific mutations show a wavelength-dependent variation in their sequence-context preference. The C → T mutation occurs most frequently in the 5'-TCG-3' sequence regardless of the UVR wavelength, but is recovered more preferentially there as the wavelength increases, resulting in prominent occurrences exclusively in the TCG sequence in the UVA wavelength range, which I will designate as a "UVA signature" in this review. The preference of the UVB-induced C → T mutation for the sequence contexts shows a mixed pattern of UVC- and UVA-induced mutations, and a similar pattern is also observed for natural sunlight, in which UVB is the most genotoxic component. In addition, the CC → TT mutation hardly occurs at UVA1 wavelengths, although it is detected rarely but constantly in the UVC and UVB ranges. This wavelength-dependent variation in the sequence-context preference of the UVR-specific mutations could be explained by two different photochemical mechanisms of cyclobutane pyrimidine dimer (CPD) formation. The UV-signature mutations observed in the UVC and UVB ranges are known to be caused mainly by CPDs produced through the conventional singlet/triplet excitation of pyrimidine bases after the direct absorption of the UVC/UVB photon energy in those bases. On the other hand, a novel photochemical mechanism through the direct absorption of the UVR energy to double-stranded DNA, which is called "collective excitation", has been proposed for the UVA-induced CPD formation. The UVA photons directly absorbed by DNA produce CPDs with a sequence context preference different from that observed for CPDs caused by the UVC/UVB-mediated singlet/triplet excitation, causing CPD formation preferentially at thymine-containing dipyrimidine sites and probably also preferably at methyl CpG-associated dipyrimidine sites, which include the TCG sequence. In this review, I present a mechanistic consideration on the wavelength-dependent variation of the sequence context preference of the UVR-specific mutations and rationalize the proposition of the UVA-signature mutation, in addition to the UV-signature mutation.
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Affiliation(s)
- Hironobu Ikehata
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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15
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cAMP-mediated regulation of melanocyte genomic instability: A melanoma-preventive strategy. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 115:247-295. [PMID: 30798934 DOI: 10.1016/bs.apcsb.2018.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Malignant melanoma of the skin is the leading cause of death from skin cancer and ranks fifth in cancer incidence among all cancers in the United States. While melanoma mortality has remained steady for the past several decades, melanoma incidence has been increasing, particularly among fair-skinned individuals. According to the American Cancer Society, nearly 10,000 people in the United States will die from melanoma this year. Individuals with dark skin complexion are protected damage generated by UV-light due to the high content of UV-blocking melanin pigment in their epidermis as well as better capacity for melanocytes to cope with UV damage. There is now ample evidence that suggests that the melanocortin 1 receptor (MC1R) is a major melanoma risk factor. Inherited loss-of-function mutations in MC1R are common in melanoma-prone persons, correlating with a less melanized skin complexion and poorer recovery from mutagenic photodamage. We and others are interested in the MC1R signaling pathway in melanocytes, its mechanisms of enhancing genomic stability and pharmacologic opportunities to reduce melanoma risk based on those insights. In this chapter, we review melanoma risk factors, the MC1R signaling pathway, and the relationship between MC1R signaling and DNA repair.
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16
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Khan AQ, Travers JB, Kemp MG. Roles of UVA radiation and DNA damage responses in melanoma pathogenesis. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:438-460. [PMID: 29466611 PMCID: PMC6031472 DOI: 10.1002/em.22176] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/18/2018] [Accepted: 01/22/2018] [Indexed: 05/10/2023]
Abstract
The growing incidence of melanoma is a serious public health issue that merits a thorough understanding of potential causative risk factors, which includes exposure to ultraviolet radiation (UVR). Though UVR has been classified as a complete carcinogen and has long been recognized for its ability to damage genomic DNA through both direct and indirect means, the precise mechanisms by which the UVA and UVB components of UVR contribute to the pathogenesis of melanoma have not been clearly defined. In this review, we therefore highlight recent studies that have addressed roles for UVA radiation in the generation of DNA damage and in modulating the subsequent cellular responses to DNA damage in melanocytes, which are the cell type that gives rise to melanoma. Recent research suggests that UVA not only contributes to the direct formation of DNA lesions but also impairs the removal of UV photoproducts from genomic DNA through oxidation and damage to DNA repair proteins. Moreover, the melanocyte microenvironment within the epidermis of the skin is also expected to impact melanomagenesis, and we therefore discuss several paracrine signaling pathways that have been shown to impact the DNA damage response in UV-irradiated melanocytes. Lastly, we examine how alterations to the immune microenvironment by UVA-associated DNA damage responses may contribute to melanoma development. Thus, there appear to be multiple avenues by which UVA may elevate the risk of melanoma. Protective strategies against excess exposure to UVA wavelengths of light therefore have the potential to decrease the incidence of melanoma. Environ. Mol. Mutagen. 59:438-460, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Aiman Q Khan
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Jeffrey B Travers
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
- Dayton Veterans Affairs Medical Center, Dayton, Ohio
| | - Michael G Kemp
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
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Su X, Liang R, Stolee JA. A facile one-step fluorescence method for the quantitation of low-content single base deamination impurity in synthetic oligonucleotides. J Pharm Biomed Anal 2018; 155:50-55. [PMID: 29614399 DOI: 10.1016/j.jpba.2018.03.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/20/2018] [Accepted: 03/25/2018] [Indexed: 11/27/2022]
Abstract
Oligonucleotides are being researched and developed as potential drug candidates for the treatment of a broad spectrum of diseases. The characterization of antisense oligonucleotide (ASO) impurities caused by base mutations (e.g. deamination) which are closely related to the target ASO is a significant analytical challenge. Herein, we describe a novel one-step method, utilizing a strategy that combines fluorescence-ON detection with competitive hybridization, to achieve single base mutation quantitation in extensively modified synthetic ASOs. Given that this method is highly specific and sensitive (LoQ = 4 nM), we envision that it will find utility for screening other impurities as well as sequencing modified oligonucleotides.
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Affiliation(s)
- Xiaoye Su
- Analytical Development, Biogen Inc., Cambridge, MA 02142, United States.
| | - Ruiting Liang
- Analytical Development, Biogen Inc., Cambridge, MA 02142, United States.
| | - Jessica A Stolee
- Analytical Development, Biogen Inc., Cambridge, MA 02142, United States.
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18
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Impact of Age and Insulin-Like Growth Factor-1 on DNA Damage Responses in UV-Irradiated Human Skin. Molecules 2017; 22:molecules22030356. [PMID: 28245638 PMCID: PMC5432641 DOI: 10.3390/molecules22030356] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 01/19/2023] Open
Abstract
The growing incidence of non-melanoma skin cancer (NMSC) necessitates a thorough understanding of its primary risk factors, which include exposure to ultraviolet (UV) wavelengths of sunlight and age. Whereas UV radiation (UVR) has long been known to generate photoproducts in genomic DNA that promote genetic mutations that drive skin carcinogenesis, the mechanism by which age contributes to disease pathogenesis is less understood and has not been sufficiently studied. In this review, we highlight studies that have considered age as a variable in examining DNA damage responses in UV-irradiated skin and then discuss emerging evidence that the reduced production of insulin-like growth factor-1 (IGF-1) by senescent fibroblasts in the dermis of geriatric skin creates an environment that negatively impacts how epidermal keratinocytes respond to UVR-induced DNA damage. In particular, recent data suggest that two principle components of the cellular response to DNA damage, including nucleotide excision repair and DNA damage checkpoint signaling, are both partially defective in keratinocytes with inactive IGF-1 receptors. Overcoming these tumor-promoting conditions in aged skin may therefore provide a way to lower aging-associated skin cancer risk, and thus we will consider how dermal wounding and related clinical interventions may work to rejuvenate the skin, re-activate IGF-1 signaling, and prevent the initiation of NMSC.
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Ikehata H, Mori T, Yamamoto M. In Vivo Spectrum of UVC-induced Mutation in Mouse Skin Epidermis May Reflect the Cytosine Deamination Propensity of Cyclobutane Pyrimidine Dimers. Photochem Photobiol 2015; 91:1488-96. [PMID: 26335024 DOI: 10.1111/php.12525] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/23/2015] [Indexed: 01/15/2023]
Abstract
Although ultraviolet radiation (UVR) has a genotoxicity for inducing skin cancers, the skin may tolerate UVC component because the epidermal layer prevents this short wavelength range from passing through. Here, UVC genotoxicity for mouse skin was evaluated in terms of DNA damage formation and mutagenicity. UVC induced UVR photolesions and mutations remarkably in the epidermis but poorly in the dermis, confirming the barrier ability of the epidermis against shorter UVR wavelengths. Moreover, the epidermis itself responded to UVC mutagenicity with mutation induction suppression, which suppressed the mutant frequencies to a remarkably low, constant level regardless of UVC dose. The mutation spectrum observed in UVC-exposed epidermis showed a predominance of UV-signature mutation, which occurred frequently in 5'-TCG-3', 5'-TCA-3' and 5'-CCA-3' contexts. Especially, for the former two contexts, the mutations recurred at several sites with more remarkable recurrences at the 5'-TCG-3' sites. Comparison of the UVC mutation spectrum with those observed in longer UVR wavelength ranges led us to a mechanism that explains why the sequence context preference of UV-signature mutation changes according to the wavelength, which is based on the difference in the mCpG preference of cyclobutane pyrimidine dimer (CPD) formation among UVR ranges and the sequence context-dependent cytosine deamination propensity of CPD.
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Affiliation(s)
- Hironobu Ikehata
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toshio Mori
- Radioisotope Research Center, Nara Medical University School of Medicine, Kashihara, Nara, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
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20
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Abstract
DNA damage is a constant threat to cells, causing cytotoxicity as well as inducing genetic alterations. The steady-state abundance of DNA lesions in a cell is minimized by a variety of DNA repair mechanisms, including DNA strand break repair, mismatch repair, nucleotide excision repair, base excision repair, and ribonucleotide excision repair. The efficiencies and mechanisms by which these pathways remove damage from chromosomes have been primarily characterized by investigating the processing of lesions at defined genomic loci, among bulk genomic DNA, on episomal DNA constructs, or using in vitro substrates. However, the structure of a chromosome is heterogeneous, consisting of heavily protein-bound heterochromatic regions, open regulatory regions, actively transcribed genes, and even areas of transient single stranded DNA. Consequently, DNA repair pathways function in a much more diverse set of chromosomal contexts than can be readily assessed using previous methods. Recent efforts to develop whole genome maps of DNA damage, repair processes, and even mutations promise to greatly expand our understanding of DNA repair and mutagenesis. Here we review the current efforts to utilize whole genome maps of DNA damage and mutation to understand how different chromosomal contexts affect DNA excision repair pathways.
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Affiliation(s)
- John J Wyrick
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA; Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA.
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA.
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21
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Cannistraro VJ, Pondugula S, Song Q, Taylor JS. Rapid deamination of cyclobutane pyrimidine dimer photoproducts at TCG sites in a translationally and rotationally positioned nucleosome in vivo. J Biol Chem 2015; 290:26597-609. [PMID: 26354431 DOI: 10.1074/jbc.m115.673301] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Indexed: 11/06/2022] Open
Abstract
Sunlight-induced C to T mutation hot spots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. The C and 5-methyl-C in CPDs are not stable and deaminate to U and T, respectively, which leads to the insertion of A by the DNA damage bypass polymerase η, thereby defining a probable mechanism for the origin of UV-induced C to T mutations. Deamination rates for T(m)CG CPDs have been found to vary 12-fold with rotational position in a nucleosome in vitro. To determine the influence of nucleosome structure on deamination rates in vivo, we determined the deamination rates of CPDs at TCG sites in a stably positioned nucleosome within the FOS promoter in HeLa cells. A procedure for in vivo hydroxyl radical footprinting with Fe-EDTA was developed, and, together with results from a cytosine methylation protection assay, we determined the translational and rotational positions of the TCG sites. Consistent with the in vitro observations, deamination was slower for one CPD located at an intermediate rotational position compared with two other sites located at outside positions, and all were much faster than for CPDs at non-TCG sites. Photoproduct formation was also highly suppressed at one site, possibly due to its interaction with a histone tail. Thus, it was shown that CPDs of TCG sites deaminate the fastest in vivo and that nucleosomes can modulate both their formation and deamination, which could contribute to the UV mutation hot spots and cold spots.
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Affiliation(s)
| | - Santhi Pondugula
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Qian Song
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - John-Stephen Taylor
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
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22
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Brash DE. UV signature mutations. Photochem Photobiol 2014; 91:15-26. [PMID: 25354245 DOI: 10.1111/php.12377] [Citation(s) in RCA: 255] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/22/2014] [Indexed: 12/17/2022]
Abstract
Sequencing complete tumor genomes and exomes has sparked the cancer field's interest in mutation signatures for identifying the tumor's carcinogen. This review and meta-analysis discusses signatures and their proper use. We first distinguish between a mutagen's canonical mutations—deviations from a random distribution of base changes to create a pattern typical of that mutagen—and the subset of signature mutations, which are unique to that mutagen and permit inference backward from mutations to mutagen. To verify UV signature mutations, we assembled literature datasets on cells exposed to UVC, UVB, UVA, or solar simulator light (SSL) and tested canonical UV mutation features as criteria for clustering datasets. A confirmed UV signature was: ≥60% of mutations are C→T at a dipyrimidine site, with ≥5% CC→TT. Other canonical features such as a bias for mutations on the nontranscribed strand or at the 3' pyrimidine had limited application. The most robust classifier combined these features with criteria for the rarity of non-UV canonical mutations. In addition, several signatures proposed for specific UV wavelengths were limited to specific genes or species; UV's nonsignature mutations may cause melanoma BRAF mutations; and the mutagen for sunlight-related skin neoplasms may vary between continents.
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Affiliation(s)
- Douglas E Brash
- Departments of Therapeutic Radiology and Dermatology, Yale School of Medicine, New Haven, CT
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23
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Ikehata H, Chang Y, Yokoi M, Yamamoto M, Hanaoka F. Remarkable induction of UV-signature mutations at the 3'-cytosine of dipyrimidine sites except at 5'-TCG-3' in the UVB-exposed skin epidermis of xeroderma pigmentosum variant model mice. DNA Repair (Amst) 2014; 22:112-22. [PMID: 25128761 DOI: 10.1016/j.dnarep.2014.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/12/2014] [Accepted: 07/21/2014] [Indexed: 10/24/2022]
Abstract
The human POLH gene is responsible for the variant form of xeroderma pigmentosum (XP-V), a genetic disease highly susceptible to cancer on sun-exposed skin areas, and encodes DNA polymerase η (polη), which is specialized for translesion DNA synthesis (TLS) of UV-induced DNA photolesions. We constructed polη-deficient mice transgenic with lacZ mutational reporter genes to study the effect of Polh null mutation (Polh(-/-)) on mutagenesis in the skin after UVB irradiation. UVB induced lacZ mutations with remarkably higher frequency in the Polh(-/-) epidermis and dermis than in the wild-type (Polh(+/+)) and heterozygote. DNA sequences of a hundred lacZ mutants isolated from the epidermis of four UVB-exposed Polh(-/-) mice were determined and compared with mutant sequences from irradiated Polh(+)(/)(+) mice. The spectra of the mutations in the two genotypes were both highly UV-specific and dominated by C→T transitions at dipyrimidines, namely UV-signature mutations. However, sequence preferences of the occurrence of UV-signature mutations were quite different between the two genotypes: the mutations occurred at a higher frequency preferentially at the 5'-TCG-3' sequence context than at the other dipyrimidine contexts in the Polh(+/+) epidermis, whereas the mutations were induced remarkably and exclusively at the 3'-cytosine of almost all dipyrimidine contexts with no preference for 5'-TCG-3' in the Polh(-/-) epidermis. In addition, in Polh(-/-) mice, a small but remarkable fraction of G→T transversions was also observed exclusively at the 3'-cytosine of dipyrimidine sites, strongly suggesting that these transversions resulted not from oxidative damage but from UV photolesions. These results would reflect the characteristics of the error-prone TLS functioning in the bypass of UV photolesions in the absence of polη, which would be mediated by mechanisms based on the two-step model of TLS. On the other hand, the deamination model would explain well the mutation spectrum in the Polh(+/+) genotype.
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Affiliation(s)
- Hironobu Ikehata
- Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Department of Physiological Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
| | - Yumin Chang
- Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Masayuki Yokoi
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo 171-8588, Japan
| | - Masayuki Yamamoto
- Department of Physiological Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Fumio Hanaoka
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo 171-8588, Japan
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24
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Kim SI, Jin SG, Pfeifer GP. Formation of cyclobutane pyrimidine dimers at dipyrimidines containing 5-hydroxymethylcytosine. Photochem Photobiol Sci 2014; 12:1409-15. [PMID: 23677065 DOI: 10.1039/c3pp50037c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Much of the cancer-causing effects of ultraviolet radiation from the sun have been linked to the formation of dimerized DNA bases. These dimeric DNA photoproducts include the cyclobutane pyrimidine dimers (CPDs) and the pyrimidine(6-4)pyrimidone photoproducts [(6-4)PPs]. CPDs are highly mutagenic and are produced in substantial quantities by UVB radiation. These dimers can form between any two adjacent pyrimidines and can involve thymine, cytosine, or 5-methylcytosine. Very recently, a sixth DNA base, 5-hydroxymethylcytosine (5hmC) has been identified and characterized as a normal component of mammalian DNA. Here, we investigated the formation of CPDs at different DNA sequences containing 5hmC following irradiation with UVA, UVB, or UVC light sources. We show that the formation of CPDs at dipyrimidines containing 5hmC occurs at different DNA sequences but is not enhanced relative to cytosine or 5-methylcytosines at the same sequence positions. In fact, in some sequence contexts, CPDs containing 5hmC are formed at very low levels. Nonetheless, CPD formation at 5hmC pyrimidines is expected to be biologically relevant since three types of human skin-derived cells, fibroblasts, keratinocytes and melanocytes, all contain detectable levels of this modified base.
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Affiliation(s)
- Sang-in Kim
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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25
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Mallet JD, Gendron SP, Drigeard Desgarnier MC, Rochette PJ. Implication of ultraviolet light in the etiology of uveal melanoma: A review. Photochem Photobiol 2014; 90:15-21. [PMID: 23981010 DOI: 10.1111/php.12161] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/03/2013] [Indexed: 12/31/2022]
Abstract
Uveal melanoma is the most frequent intraocular cancer and the second most common form of melanoma. It metastasizes in half of the patients and the prognostic is poor. Although ultraviolet (UV) radiation is a proven risk factor for skin melanoma, the role of UV light in the etiology of uveal melanoma is still contradictory. We have compared epidemiological and genetic evidences of the potential role of UV radiation in uveal melanoma with data on cutaneous melanoma. Even though frequently mutated genes in skin melanoma (e.g. BRAF) differ from those found in uveal melanoma (i.e. GNAQ, GNA11), their mutation pattern bears strong similarities. Furthermore, we provide new results showing that RAC1, a gene recently found harboring UV-hallmark mutation in skin melanoma, is also mutated in uveal melanoma. This article aims to review the work done in the last decades to understand the etiology of uveal melanoma and discuss new avenues, which shed some light on the potential role of UV exposure in uveal melanoma.
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Affiliation(s)
- Justin D Mallet
- Axe Médecine Régénératrice, Centre de Recherche FRQS du CHU de Québec, Hôpital du Saint-Sacrement, QC, Canada
- Centre LOEX de l'Université Laval, QC, Canada
| | - Sébastien P Gendron
- Axe Médecine Régénératrice, Centre de Recherche FRQS du CHU de Québec, Hôpital du Saint-Sacrement, QC, Canada
- Centre LOEX de l'Université Laval, QC, Canada
| | - Marie-Catherine Drigeard Desgarnier
- Axe Médecine Régénératrice, Centre de Recherche FRQS du CHU de Québec, Hôpital du Saint-Sacrement, QC, Canada
- Centre LOEX de l'Université Laval, QC, Canada
| | - Patrick J Rochette
- Axe Médecine Régénératrice, Centre de Recherche FRQS du CHU de Québec, Hôpital du Saint-Sacrement, QC, Canada
- Centre LOEX de l'Université Laval, QC, Canada
- Département d'Ophtalmologie et ORL - Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, QC, Canada
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Fischer C, Ahlrichs WH, Buma AGJ, van de Poll WH, Bininda-Emonds ORP. How does the 'ancient' asexual Philodina roseola (Rotifera: Bdelloidea) handle potential UVB-induced mutations? ACTA ACUST UNITED AC 2013; 216:3090-5. [PMID: 23619410 DOI: 10.1242/jeb.087064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Like other obligate asexuals, bdelloid rotifers are expected to suffer from degradation of their genomes through processes including the accumulation of deleterious mutations. However, sequence-based analyses in this regard remain inconclusive. Instead of looking for historical footprints of mutations in these ancient asexuals, we directly examined the susceptibility and ability to repair point mutations by the bdelloid Philodina roseola by inducing cyclobutane-pyrimidine dimers (CPDs) via exposure to UVB radiation (280-320 nm). For comparison, we performed analogous experiments with the facultative asexual monogonont rotifer Brachionus rubens. Different strategies were found for the two species. Philodina roseola appeared to shield itself from CPD induction through uncharacterized UV-absorbing compounds and, except for the genome reconstruction that occurs after desiccation, was largely unable to repair UVB-induced damage. By contrast, B. rubens was more susceptible to UVB irradiation, but could repair all induced damage in ~2 h. In addition, whereas UV irradiation had a significant negative impact on the reproductive output of P. roseola, and especially so after desiccation, that of B. rubens was unaffected. Although the strategy of P. roseola might suffice under natural conditions where UVB irradiation is less intense, the lack of any immediate CPD repair mechanisms in this species remains perplexing. It remains to be investigated how typical these results are for bdelloids as a group and therefore how reliant these animals are on desiccation-dependent genome repair to correct potential DNA damage given their obligate asexual lifestyle.
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Affiliation(s)
- Claus Fischer
- AG Systematics and Evolutionary Biology, IBU-Faculty V, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.
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27
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Budden T, Bowden NA. The role of altered nucleotide excision repair and UVB-induced DNA damage in melanomagenesis. Int J Mol Sci 2013; 14:1132-51. [PMID: 23303275 PMCID: PMC3565312 DOI: 10.3390/ijms14011132] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/29/2012] [Accepted: 12/26/2012] [Indexed: 01/12/2023] Open
Abstract
UVB radiation is the most mutagenic component of the UV spectrum that reaches the earth's surface and causes the development of DNA damage in the form of cyclobutane pyrimidine dimers and 6-4 photoproducts. UV radiation usually results in cellular death, but if left unchecked, it can affect DNA integrity, cell and tissue homeostasis and cause mutations in oncogenes and tumour-suppressor genes. These mutations, if unrepaired, can lead to abnormal cell growth, increasing the risk of cancer development. Epidemiological data strongly associates UV exposure as a major factor in melanoma development, but the exact biological mechanisms involved in this process are yet to be fully elucidated. The nucleotide excision repair (NER) pathway is responsible for the repair of UV-induced lesions. Patients with the genetic disorder Xeroderma Pigmentosum have a mutation in one of eight NER genes associated with the XP complementation groups XP-A to XP-G and XP variant (XP-V). XP is characterized by diminished repair capacity, as well as a 1000-fold increase in the incidence of skin cancers, including melanoma. This has suggested a significant role for NER in melanoma development as a result of UVB exposure. This review discusses the current research surrounding UVB radiation and NER capacity and how further investigation of NER could elucidate the role of NER in avoiding UV-induced cellular death resulting in melanomagenesis.
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Affiliation(s)
- Timothy Budden
- Centre for Information Based Medicine, Hunter Medical Research Institute, and School of Biomedical Sciences & Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2289, Australia.
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28
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Mallet JD, Rochette PJ. Wavelength-dependent ultraviolet induction of cyclobutane pyrimidine dimers in the human cornea. Photochem Photobiol Sci 2013; 12:1310-8. [DOI: 10.1039/c3pp25408a] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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29
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Song Q, Sherrer SM, Suo Z, Taylor JS. Preparation of site-specific T=mCG cis-syn cyclobutane dimer-containing template and its error-free bypass by yeast and human polymerase η. J Biol Chem 2012; 287:8021-8. [PMID: 22262850 DOI: 10.1074/jbc.m111.333591] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
C-to-T mutations are a hallmark of UV light and, in humans, occur preferentially at methylated Py(m)CG sites, which are also sites of preferential cyclobutane pyrimidine dimer (CPD) formation. In response, cells have evolved DNA damage bypass polymerases, of which polymerase η (pol η) appears to be specifically adapted to synthesize past cis-syn CPDs. Although T=T CPDs are stable, CPDs containing C or 5-methylcytosine ((m)C) are not and spontaneously deaminate to U or T at pH 7 and 37 °C over a period of hours or days, making their preparation and study difficult. Furthermore, there is evidence to suggest that, depending on solvent polarity, a C or an (m)C in a CPD can adopt three tautomeric forms, one of which could code as T. Although many in vitro studies have established that synthesis past T or U in a CPD by pol η occurs in a highly error-free manner, the only in vitro evidence that synthesis past C or (m)C in a CPD also occurs in an error-free manner is for an (m)C in the 5'-position of an (m)C=T CPD. Herein, we describe the preparation and characterization of an oligodeoxynucleotide containing a CPD of a T(m)CG site, one of the major sites of C methylation and C-to-T mutations found in the p53 gene of basal and squamous cell cancers. We also demonstrate that both yeast and human pol η synthesize past the 3'-(m)C CPD in a >99% error-free manner, consistent with the highly water-exposed nature of the active site.
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Affiliation(s)
- Qian Song
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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Pfeifer GP, Besaratinia A. UV wavelength-dependent DNA damage and human non-melanoma and melanoma skin cancer. Photochem Photobiol Sci 2011; 11:90-7. [PMID: 21804977 DOI: 10.1039/c1pp05144j] [Citation(s) in RCA: 266] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ultraviolet (UV) irradiation from the sun has been epidemiologically and mechanistically linked to skin cancer, a spectrum of diseases of rising incidence in many human populations. Both non-melanoma and melanoma skin cancers are associated with sunlight exposure. In this review, we discuss the UV wavelength-dependent formation of the major UV-induced DNA damage products, their repair and mutagenicity and their potential involvement in sunlight-associated skin cancers. We emphasize the major role played by the cyclobutane pyrimidine dimers (CPDs) in skin cancer mutations relative to that of (6-4) photoproducts and oxidative DNA damage. Collectively, the data implicate the CPD as the DNA lesion most strongly involved in human cancers induced by sunlight.
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Affiliation(s)
- Gerd P Pfeifer
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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Besaratinia A, Yoon JI, Schroeder C, Bradforth SE, Cockburn M, Pfeifer GP. Wavelength dependence of ultraviolet radiation-induced DNA damage as determined by laser irradiation suggests that cyclobutane pyrimidine dimers are the principal DNA lesions produced by terrestrial sunlight. FASEB J 2011; 25:3079-91. [PMID: 21613571 DOI: 10.1096/fj.11-187336] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
To elucidate the involvement of specific ultraviolet (UV) wavelengths in solar mutagenesis, we used a laser system to investigate the induction of DNA damage, both in the overall genome and at the nucleotide resolution level, in the genomic DNA of transgenic Big Blue mouse fibroblasts irradiated with a series of UV wavelengths, inclusive of UVC (λ<280 nm), UVB (λ=280-320 nm), and UVA (λ>320 nm). Subsequently, we sought correlation between the locations of UV-induced DNA lesions in the cII transgene of irradiated DNA samples and the frequency distribution and codon position of the induced cII mutations in counterpart mouse cells irradiated with simulated sunlight. Using a combination of enzymatic digestion assays coupled with gel electrophoresis, immunodot blot assays, and DNA footprinting assays, we demonstrated a unique wavelength-dependent formation of photodimeric lesions, i.e., cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts [(6-4)PPs], based on direct UV absorption of DNA, in irradiated mouse genomic DNA, which could partially explain the induction of mutations in mouse cells irradiated with simulated sunlight. Most notably, there was a divergence of CPD and (6-4)PP formation at an irradiation wavelength of 296 nm in mouse genomic DNA. Whereas substantial formation of (6-4)PPs was detectable in samples irradiated at this wavelength, which intensified as the irradiation wavelength decreased, only small quantities of these lesions were found in samples irradiated at wavelengths of 300-305 nm, with no detectable level of (6-4)PPs in samples irradiated with longer wavelengths. Although CPD formation followed the same pattern of increase with decreasing wavelengths of irradiation, there were substantial levels of CPDs in samples irradiated with UVB wavelengths borderlined with UVA, and small but detectable levels of these lesions in samples irradiated with longer wavelengths. Because the terrestrial sunlight spectrum rolls off sharply at wavelengths ~300 nm, our findings suggest that CPDs are the principal lesion responsible for most DNA damage-dependent biological effects of sunlight.
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Affiliation(s)
- Ahmad Besaratinia
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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Abstract
Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: "error-free" bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases--the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation.
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Affiliation(s)
- Hironobu Ikehata
- Division of Genome and Radiation Biology, Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
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Song Q, Cannistraro VJ, Taylor JS. Rotational position of a 5-methylcytosine-containing cyclobutane pyrimidine dimer in a nucleosome greatly affects its deamination rate. J Biol Chem 2010; 286:6329-35. [PMID: 21160086 DOI: 10.1074/jbc.m110.183178] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
C to T mutation hotspots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. These mutations are proposed to arise from the insertion of A by DNA polymerase η opposite the T that results from deamination of the methylC ((m)C) within the CPD. Although the frequency of CPD formation and repair is modestly modulated by its rotational position within a nucleosome, the effect of position on the rate of (m)C deamination in a CPD has not been previously studied. We now report that deamination of a T(m)C CPD whose sugar phosphate backbone is positioned against the histone core surface decreases by a factor of 4.7, whereas that of a T(m)C CPD positioned away from the surface increases by a factor of 8.9 when compared with unbound DNA. Because the (m)Cs undergoing deamination are in similar steric environments, the difference in rate appears to be a consequence of a difference in the flexibility and compression of the two sites due to DNA bending. Considering that formation of the CPD positioned away from the surface is also enhanced by a factor of two, a T(m)CG site in this position might be expected to have up to an 84-fold higher probability of resulting in a UV-induced (m)C to T mutation than one positioned against the surface. These results indicate that rotational position may play an important role in the formation of UV-induced C to T mutation hotspots, as well as in the mutagenic mechanism of other DNA lesions.
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Affiliation(s)
- Qian Song
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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Heil K, Pearson D, Carell T. Chemical investigation of light induced DNA bipyrimidine damage and repair. Chem Soc Rev 2010; 40:4271-8. [PMID: 21076781 DOI: 10.1039/c000407n] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In all organisms, genetic information is stored in DNA and RNA. Both of these macromolecules are damaged by many exogenous and endogenous events, with UV irradiation being one of the major sources of damage. The major photolesions formed are the cyclobutane pyrimidine dimers (CPD), pyrimidine-pyrimidone-(6-4)-photoproducts, Dewar valence isomers and, for dehydrated spore DNA, 5-(α-thyminyl)-5,6-dihydrothymine (SP). In order to be able to investigate how nature's repair and tolerance mechanisms protect the integrity of genetic information, oligonucleotides containing sequence and site-specific UV lesions are essential. This tutorial review provides an overview of synthetic procedures by which these oligonucleotides can be generated, either through phosphoramidite chemistry or direct irradiation of DNA. Moreover, a brief summary on their usage in analysing repair and tolerance processes as well as their biological effects is provided.
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Affiliation(s)
- Korbinian Heil
- Center for Integrative Protein Science CiPSM at the Department of Chemistry and Biochemistry, Ludwig-Maximilians University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
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Yamamoto J, Nishiguchi K, Manabe K, Masutani C, Hanaoka F, Iwai S. Photosensitized [2 + 2] cycloaddition of N-acetylated cytosine affords stereoselective formation of cyclobutane pyrimidine dimer. Nucleic Acids Res 2010; 39:1165-75. [PMID: 20880992 PMCID: PMC3035463 DOI: 10.1093/nar/gkq855] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Photocycloaddition between two adjacent bases in DNA produces a cyclobutane pyrimidine dimer (CPD), which is one of the major UV-induced DNA lesions, with either the cis-syn or trans-syn structure. In this study, we investigated the photosensitized intramolecular cycloaddition of partially-protected thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxy-5-methylcytidine, to clarify the effect of the base modification on the cycloaddition reaction. The reaction resulted in the stereoselective formation of the trans-syn CPD, followed by hydrolysis of the acetylamino group. The same result was obtained for the photocycloaddition of thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxycytidine, whereas both the cis-syn and trans-syn CPDs were formed from thymidylyl-(3'→5')-thymidine. Kinetic analyses revealed that the activation energy of the acid-catalyzed hydrolysis is comparable to that reported for the thymine-cytosine CPD. These findings provided a new strategy for the synthesis of oligonucleotides containing the trans-syn CPD. Using the synthesized oligonucleotide, translesion synthesis by human DNA polymerase η was analyzed.
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Affiliation(s)
- Junpei Yamamoto
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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Cannistraro VJ, Taylor JSA. Methyl CpG binding protein 2 (MeCP2) enhances photodimer formation at methyl-CpG sites but suppresses dimer deamination. Nucleic Acids Res 2010; 38:6943-55. [PMID: 20601406 PMCID: PMC2978359 DOI: 10.1093/nar/gkq582] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Spontaneous deamination of cytosine to uracil in DNA is a ubiquitous source of C→T mutations, but occurs with a half life of ∼50 000 years. In contrast, cytosine within sunlight induced cyclobutane dipyrimidine dimers (CPD's), deaminate within hours to days. Methylation of C increases the frequency of CPD formation at PyCG sites which correlate with C→T mutation hotspots in skin cancers. MeCP2 binds to mCG sites and acts as a transcriptional regulator and chromatin modifier affecting thousands of genes, but its effect on CPD formation and deamination is unknown. We report that the methyl CpG binding domain of MeCP2 (MBD) greatly enhances C=mC CPD formation at a TCmCG site in duplex DNA and binds with equal or better affinity to the CPD-containing duplex compared with the undamaged duplex. In comparison, MBD does not enhance T=mC CPD formation at a TTmCG site, but instead increases CPD formation at the adjacent TT site. MBD was also found to completely suppress deamination of the T=mCG CPD, suggesting that MeCP2 may have the capability to both suppress UV mutagenesis at PymCpG sites as well as enhance it.
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Lacoste S, Rochette PJ, Drouin R. [Mapping DNA damage to understand somatic mutagenesis]. Med Sci (Paris) 2010; 26:193-200. [PMID: 20188052 DOI: 10.1051/medsci/2010262193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Somatic mutation theory explains how DNA damage can lead to the malignant transformation of cells. It therefore elucidates the connection between genotoxic agents and cancers. Mutational spectra, which tend to be characteristic of a cancer type, are available for certain genes like p53 which is frequently mutated in tumors. A mutational spectrum could therefore be the signature of the genotoxic agent(s) at the origin of the malignant transformation. Ligation-mediated PCR (LMPCR) is a genomic sequencing method that can be used for the mapping of DNA damage at nucleotide resolution. Such a mapping can then be compared to a mutational spectrum to test the hypothesis that implies one agent can cause mutations into one cancer type. LMPCR has been used this way to map DNA damage generated by different UV wavelengths. The frequently damaged sites following UVB irradiation correlate with the mutational spectrum of p53 in skin cancer. Similarly, BPDE, the activated form of the benzo[a]pyrene present in tobacco smoke, generates frequent adducts at sites corresponding to mutation hotspots of p53 in lung cancers. Still, the correlation between BPDE damage sites and p53 mutations is not perfect and this suggests a role of other genotoxic substances that are also present in tobacco smoke, such as the nitrosamine NNK. Finally, and beyond this objective of better understanding somatic mutagenesis, LMPCR is commonly used whenever DNA damage frequency and/or repair is to be investigated.
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Affiliation(s)
- Sandrine Lacoste
- Département de pédiatrie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1H 5N4 Canada
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Hendriks G, Calléja F, Besaratinia A, Vrieling H, Pfeifer GP, Mullenders LHF, Jansen JG, de Wind N. Transcription-dependent cytosine deamination is a novel mechanism in ultraviolet light-induced mutagenesis. Curr Biol 2009; 20:170-5. [PMID: 20045328 DOI: 10.1016/j.cub.2009.11.061] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 11/11/2009] [Accepted: 11/17/2009] [Indexed: 11/29/2022]
Abstract
Skin cancer is the most ubiquitous cancer type in the Caucasian population, and its incidence is increasing rapidly [1]. Transcribed proliferation-related genes in dermal stem cells are targets for the induction of ultraviolet light (UV)-induced mutations that drive carcinogenesis. We have recently found that transcription of a gene increases its mutability by UV in mammalian stem cells, suggesting a role of transcription in skin carcinogenesis [2]. Here we show that transcription-associated UV-induced nucleotide substitutions are caused by increased deamination of cytosines to uracil within photolesions at the transcribed strand, presumably at sites of stalled transcription complexes. Additionally, via an independent mechanism, transcription of UV-damaged DNA induces the generation of intragenic deletions. We demonstrate that transcription-coupled nucleotide excision repair (TC-NER) provides protection against both classes of transcription-associated mutagenesis. Combined, these results unveil the existence of two mutagenic pathways operating specifically at the transcribed DNA strand of active genes. Moreover, these results uncover a novel role for TC-NER in the suppression of UV-induced genome aberrations and provide a rationale for the efficient induction of apoptosis by stalled transcription complexes.
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Affiliation(s)
- Giel Hendriks
- Department of Toxicogenetics, Leiden University Medical Center (LUMC), PO Box 9600, 2300 RC, Leiden, The Netherlands
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Cannistraro VJ, Taylor JS. Acceleration of 5-methylcytosine deamination in cyclobutane dimers by G and its implications for UV-induced C-to-T mutation hotspots. J Mol Biol 2009; 392:1145-57. [PMID: 19631218 DOI: 10.1016/j.jmb.2009.07.048] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 07/15/2009] [Accepted: 07/16/2009] [Indexed: 10/20/2022]
Abstract
Sunlight-induced C-->T mutation hotspots occur most frequently at methylated CpG sites in tumor suppressor genes and are thought to arise from translesion synthesis past deaminated cyclobutane pyrimidine dimers (CPDs). While it is known that methylation enhances CPD formation in sunlight, little is known about the effect of methylation and sequence context on the deamination of 5-methylcytosine ((m)C) and its contribution to mutagenesis at these hotspots. Using an enzymatic method, we have determined the yields and deamination rates of C and (m)C in CPDs and find that the frequency of UVB-induced CPDs correlates with the oxidation potential of the flanking bases. We also found that the deamination of T(m)C and (m)CT CPDs is about 25-fold faster when flanked by G's than by A's, C's or T's in duplex DNA and appears to involve catalysis by the O6 group of guanine. In contrast, the first deamination of either C or (m)C in AC(m)CG with a flanking G was much slower (t(1/2) >250 h) and rate limiting, while the second deamination was much faster. The observation that C(m)CG dimers deaminate very slowly but at the same time correlate with C-->T mutation hotspots suggests that their repair must be slow enough to allow sufficient time for deamination. There are, however, a greater number of single C-->T mutations than CC-->TT mutations at C(m)CG sites even though the second deamination is very fast, which could reflect faster repair of doubly deaminated dimers.
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Rochette PJ, Lacoste S, Therrien JP, Bastien N, Brash DE, Drouin R. Influence of cytosine methylation on ultraviolet-induced cyclobutane pyrimidine dimer formation in genomic DNA. Mutat Res 2009; 665:7-13. [PMID: 19427505 DOI: 10.1016/j.mrfmmm.2009.02.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 01/25/2009] [Accepted: 02/17/2009] [Indexed: 10/21/2022]
Abstract
The ultraviolet (UV) component of sunlight is the main cause of skin cancer. More than 50% of all non-melanoma skin cancers and >90% of squamous cell carcinomas in the US carry a sunlight-induced mutation in the p53 tumor suppressor gene. These mutations have a strong tendency to occur at methylated cytosines. Ligation-mediated PCR (LMPCR) was used to compare at nucleotide resolution DNA photoproduct formation at dipyrimidine sites either containing or lacking a methylated cytosine. For this purpose, we exploited the fact that the X chromosome is methylated in females only on the inactive X chromosome, and that the FMR1 (fragile-X mental retardation 1) gene is methylated only in fragile-X syndrome male patients. Purified genomic DNA was irradiated with UVC (254nm), UVB (290-320nm) or monochromatic UVB (302 and 313nm) to determine the effect of different wavelengths on cyclobutane pyrimidine dimer (CPD) formation along the X-linked PGK1 (phosphoglycerate kinase 1) and FMR1 genes. We show that constitutive methylation of cytosine increases the frequency of UVB-induced CPD formation by 1.7-fold, confirming that methylation per se is influencing the probability of damage formation. This was true for both UVB sources used, either broadband or monochromatic, but not for UVC. Our data prove unequivocally that following UVB exposure methylated cytosines are significantly more susceptible to CPD formation compared with unmethylated cytosines.
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Affiliation(s)
- Patrick J Rochette
- Division of Pathology, Department of Medical Biology, Université Laval, Québec, QC, Canada
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Yonekura SI, Nakamura N, Yonei S, Zhang-Akiyama QM. Generation, biological consequences and repair mechanisms of cytosine deamination in DNA. JOURNAL OF RADIATION RESEARCH 2009; 50:19-26. [PMID: 18987436 DOI: 10.1269/jrr.08080] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Base moieties in DNA are spontaneously threatened by naturally occurring chemical reactions such as deamination, hydrolysis and oxidation. These DNA modifications have been considered to be major causes of cell death, mutations and cancer induction in organisms. Organisms have developed the DNA base excision repair pathway as a defense mechanism to protect them from these threats. DNA glycosylases, the key enzyme in the base excision repair pathway, are highly conserved in evolution. Uracil constantly occurs in DNA. Uracil in DNA arises by spontaneous deamination of cytosine to generate pro-mutagenic U:G mispairs. Uracil in DNA is also produced by the incorporation of dUMP during DNA replication. Uracil-DNA glycosylase (UNG) acts as a major repair enzyme that protects DNA from the deleterious consequences of uracil. The first UNG activity was discovered in E. coli in 1974. This was also the first discovery of base excision repair. The sequence encoded by the ung gene demonstrates that the E. coli UNG is highly conserved in viruses, bacteria, archaea, yeast, mice and humans. In this review, we will focus on central and recent findings on the generation, biological consequences and repair mechanisms of uracil in DNA and on the biological significance of uracil-DNA glycosylase.
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Affiliation(s)
- Shin-Ichiro Yonekura
- Department of Biological Sciences, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
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Vreeswijk MPG, Meijers CM, Giphart-Gassler M, Vrieling H, van Zeeland AA, Mullenders LHF, Loenen WAM. Site-specific analysis of UV-induced cyclobutane pyrimidine dimers in nucleotide excision repair-proficient and -deficient hamster cells: Lack of correlation with mutational spectra. Mutat Res 2008; 663:7-14. [PMID: 19150617 DOI: 10.1016/j.mrfmmm.2008.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 12/16/2008] [Accepted: 12/19/2008] [Indexed: 12/14/2022]
Abstract
Irradiation of cells with UVC light induces two types of mutagenic DNA photoproducts, i.e. cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4 PP). To investigate the relationship between the frequency of UV-induced photolesions at specific sites and their ability to induce mutations, we quantified CPD formation at the nucleotide level along exons 3 and 8 of the hprt gene using ligation-mediated PCR, and determined the mutational spectrum of 132 UV-induced hprt mutants in the AA8 hamster cell line and of 165 mutants in its nucleotide excision repair-defective derivative UV5. In AA8 cells, transversions predominated with a strong strand bias towards thymine-containing photolesions in the non-transcribed strand. As hamster AA8 cells are proficient in global genome repair of 6-4 PP but selectively repair CPD from the transcribed strand of active genes, most mutations probably resulted from erroneous bypass of CPD in the non-transcribed strand. However, the relative incidence of CPD and the positions where mutations most frequently arose do not correlate. In fact some major damage sites hardly gave rise to the formation of mutations. In the repair-defective UV5 cells, mutations were almost exclusively C>T transitions caused by photoproducts at PyC sites in the transcribed strand. Even though CPD were formed at high frequencies at some TT sites in UV5, these photoproducts did not contribute to mutation induction at all. We conclude that, even in the absence of repair, large variations in the level of induction of CPD at different sites throughout the two exons do not correspond to frequencies of mutation induction.
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Affiliation(s)
- Maaike P G Vreeswijk
- Department of Toxicogenetics, Leiden University Medical Center, Leiden, The Netherlands.
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Mouret S, Charveron M, Favier A, Cadet J, Douki T. Differential repair of UVB-induced cyclobutane pyrimidine dimers in cultured human skin cells and whole human skin. DNA Repair (Amst) 2008; 7:704-12. [PMID: 18313369 DOI: 10.1016/j.dnarep.2008.01.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 12/13/2022]
Abstract
Cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are the two main classes of mutagenic DNA damages induced by UVB radiation. Numerous studies have been devoted so far to their formation and repair in human cells and skin. However, the biochemical methods used often lack the specificity that would allow the individual study of each of the four CPDs and 6-4PPs produced at TT, TC, CT and CC dinucleotides. In the present work, we applied an HPLC-mass spectrometry assay to study the formation and repair of CPDs and 6-4PPs photoproducts in primary cultures of human keratinocytes and fibroblasts as well as in whole human skin. We first observed that the yield of dimeric lesions was slightly higher in fibroblasts than in keratinocytes. In contrast, the rate of global repair was higher in the last cell type. Moreover, removal of DNA photoproducts in skin biopsies was found to be slower than in both cultured skin cells. In agreement with previous works, the repair of 6-4PPs was found to be more efficient than that of CPDs in the three types of samples, with no observed difference between the removal of the TT and TC derivatives. In contrast, a significant influence of the nature of the two modified pyrimidines was observed on the repair rate of CPDs. The decreasing order of removal efficiency was the following: C<>T>C<>C>T<>C>T<>T. These data, together with the known intrinsic mutational properties of the lesions, would support the reported UV mutation spectra. A noticeable exception concerns CC dinucleotides that are mutational hotspots with an UV-specific CC to TT tandem mutation, although related bipyrimidine photoproducts are produced in low yields and efficiently repaired.
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Affiliation(s)
- Stéphane Mouret
- Laboratoire Lésions des Acides Nucléiques, Service de Chimie Inorganique et Biologique UMR-E 3 CEA-UJF, CEA/DSM/Département de Recherche Fondamentale sur la Matière Condensée, CEA-Grenoble, 38054 Grenoble Cedex 9, France
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Matsumura T, Ogino M, Nagayoshi K, Fujimoto K. Photochemical Site-specific Mutation of 5-Methylcytosine to Thymine. CHEM LETT 2008. [DOI: 10.1246/cl.2008.94] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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45
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Yoshihara R, Nakane C, Sato R, Yasuda A, Takimoto K. Silencing of CPD Photolyase Makes Arabidopsis Hypersensitive and Hypermutable in Response to UV-B Radiation. Genes Environ 2008. [DOI: 10.3123/jemsge.30.53] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Ikehata H, Ono T. Significance of CpG methylation for solar UV-induced mutagenesis and carcinogenesis in skin. Photochem Photobiol 2007; 83:196-204. [PMID: 16620158 DOI: 10.1562/2006-02-28-ir-822] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations detected in the p53 gene in human nonmelanoma skin cancers show a highly UV-specific mutation pattern, a dominance of C --> T base substitutions at dipyrimidine sites plus frequent CC --> TT tandem substitutions, indicating a major involvement of solar UV in the skin carcinogenesis. These mutations also have another important characteristic of frequent occurrences at CpG dinucleotide sites, some of which actually show prominent hotspots in the p53 gene. Although mammalian solar UV-induced mutation spectra were studied intensively in the aprt gene using rodent cultured cells and the UV-specific mutation pattern was confirmed, the second characteristic of the p53 mutations in human skin cancers had not been reproduced. However, studies with transgenic mouse systems developed thereafter for mutation research, which harbor methyl CpG-abundant transgenes as mutation markers, yielded complete reproductions of the situation of the human skin cancer mutations in terms of both the UV-specific pattern and the frequent occurrence at CpG sites. In this review, we evaluate the significance of the CpG methylation for solar UV mutagenesis in the mammalian genome, which would lead to skin carcinogenesis. We propose that the UV-specific mutations at methylated CpG sites, C --> T transitions at methyl CpG-associated dipyrimidine sites, are a solar UV-specific mutation signature, and have estimated the wavelength range effective for the solar-UV-specific mutation as 310-340 nm. We also recommend the use of methyl CpG-enriched sequences as mutational targets for studies on solar-UV genotoxicity for human, rather than conventional mammalian mutational marker genes such as the aprt and hprt genes.
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Affiliation(s)
- Hironobu Ikehata
- Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
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Sousa MML, Krokan HE, Slupphaug G. DNA-uracil and human pathology. Mol Aspects Med 2007; 28:276-306. [PMID: 17590428 DOI: 10.1016/j.mam.2007.04.006] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 04/26/2007] [Indexed: 01/08/2023]
Abstract
Uracil is usually an inappropriate base in DNA, but it is also a normal intermediate during somatic hypermutation (SHM) and class switch recombination (CSR) in adaptive immunity. In addition, uracil is introduced into retroviral DNA by the host as part of a defence mechanism. The sources of uracil in DNA are spontaneous or enzymatic deamination of cytosine (U:G mispairs) and incorporation of dUTP (U:A pairs). Uracil in DNA is removed by a uracil-DNA glycosylase. The major ones are nuclear UNG2 and mitochondrial UNG1 encoded by the UNG-gene, and SMUG1 that also removes oxidized pyrimidines, e.g. 5-hydroxymethyluracil. The other ones are TDG that removes U and T from mismatches, and MBD4 that removes U from CpG contexts. UNG2 is found in replication foci during the S-phase and has a distinct role in repair of U:A pairs, but it is also important in U:G repair, a function shared with SMUG1. SHM is initiated by activation-induced cytosine deaminase (AID), followed by removal of U by UNG2. Humans lacking UNG2 suffer from recurrent infections and lymphoid hyperplasia, and have skewed SHM and defective CSR, resulting in elevated IgM and strongly reduced IgG, IgA and IgE. UNG-defective mice also develop B-cell lymphoma late in life. In the defence against retrovirus, e.g. HIV-1, high concentrations of dUTP in the target cells promotes misincorporation of dUMP-, and host cell APOBEC proteins may promote deamination of cytosine in the viral DNA. This facilitates degradation of viral DNA by UNG2 and AP-endonuclease. However, viral proteins Vif and Vpr counteract this defense by mechanisms that are now being revealed. In conclusion, uracil in DNA is both a mutagenic burden and a tool to modify DNA for diversity or degradation.
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Affiliation(s)
- Mirta M L Sousa
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7006 Trondheim, Norway
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Courdavault S, Baudouin C, Sauvaigo S, Mouret S, Candéias S, Charveron M, Favier A, Cadet J, Douki T. Unrepaired Cyclobutane Pyrimidine Dimers Do Not Prevent Proliferation of UV-B-irradiated Cultured Human Fibroblasts¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00004.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ohkumo T, Kondo Y, Yokoi M, Tsukamoto T, Yamada A, Sugimoto T, Kanao R, Higashi Y, Kondoh H, Tatematsu M, Masutani C, Hanaoka F. UV-B radiation induces epithelial tumors in mice lacking DNA polymerase eta and mesenchymal tumors in mice deficient for DNA polymerase iota. Mol Cell Biol 2006; 26:7696-706. [PMID: 17015482 PMCID: PMC1636855 DOI: 10.1128/mcb.01076-06] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
DNA polymerase eta (Pol eta) is the product of the Polh gene, which is responsible for the group variant of xeroderma pigmentosum, a rare inherited recessive disease which is characterized by susceptibility to sunlight-induced skin cancer. We recently reported in a study of Polh mutant mice that Pol eta is involved in the somatic hypermutation of immunoglobulin genes, but the cancer predisposition of Polh-/- mice has not been examined until very recently. Another translesion synthesis polymerase, Pol iota, a Pol eta paralog encoded by the Poli gene, is naturally deficient in the 129 mouse strain, and the function of Pol iota is enigmatic. Here, we generated Polh Poli double-deficient mice and compared the tumor susceptibility of them with Polh- or Poli-deficient animals under the same genetic background. While Pol iota deficiency does not influence the UV sensitivity of mouse fibroblasts irrespective of Polh genotype, Polh Poli double-deficient mice show slightly earlier onset of skin tumor formation. Intriguingly, histological diagnosis after chronic treatment with UV light reveals that Pol iota deficiency leads to the formation of mesenchymal tumors, such as sarcomas, that are not observed in Polh(-/-) mice. These results suggest the involvement of the Pol eta and Pol iota proteins in UV-induced skin carcinogenesis.
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Affiliation(s)
- Tsuyoshi Ohkumo
- Cellular Biology Laboratory, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan
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Borgdorff V, Pauw B, van Hees-Stuivenberg S, de Wind N. DNA mismatch repair mediates protection from mutagenesis induced by short-wave ultraviolet light. DNA Repair (Amst) 2006; 5:1364-72. [PMID: 16880010 DOI: 10.1016/j.dnarep.2006.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 06/08/2006] [Accepted: 06/13/2006] [Indexed: 01/24/2023]
Abstract
To investigate involvement of DNA mismatch repair in the response to short-wave ultraviolet (UVC) light, we compared UVC-induced mutant frequencies and mutational spectra at the Hprt gene between wild type and mismatch-repair-deficient mouse embryonic stem (ES) cells. Whereas mismatch repair gene status did not significantly affect survival of these cells after UVC irradiation, UVC induced substantially more mutations in ES cells that lack the MutSalpha mismatch-recognizing heterodimer than in wild type ES cells. The global UVC-induced mutational spectra at Hprt and the distribution of most spectral mutational hotspots were found to be similar in mismatch-repair-deficient and wild type cells. However, at one predominant spectral hot spot for mutagenesis in wild type cells, the UVC-induced mutation frequency was not affected by the mismatch repair status. Together these data reveal a major role of mismatch repair in controlling mutagenesis induced by UVC light and may suggest the sequence context-dependent direct mismatch repair of misincorporations opposite UVC-induced pyrimidine dimers.
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Affiliation(s)
- Viola Borgdorff
- Department of Toxicogenetics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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