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Chung WH. Signification and Application of Mutator and Antimutator Phenotype-Induced Genetic Variations in Evolutionary Adaptation and Cancer Therapeutics. J Microbiol 2023; 61:1013-1024. [PMID: 38100001 DOI: 10.1007/s12275-023-00091-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 01/11/2024]
Abstract
Mutations present a dichotomy in their implications for cellular processes. They primarily arise from DNA replication errors or damage repair processes induced by environmental challenges. Cumulative mutations underlie genetic variations and drive evolution, yet also contribute to degenerative diseases such as cancer and aging. The mutator phenotype elucidates the heightened mutation rates observed in malignant tumors. Evolutionary adaptation, analogous to bacterial and eukaryotic systems, manifests through mutator phenotypes during changing environmental conditions, highlighting the delicate balance between advantageous mutations and their potentially detrimental consequences. Leveraging the genetic tractability of Saccharomyces cerevisiae offers unique insights into mutator phenotypes and genome instability akin to human cancers. Innovative reporter assays in yeast model organisms enable the detection of diverse genome alterations, aiding a comprehensive analysis of mutator phenotypes. Despite significant advancements, our understanding of the intricate mechanisms governing spontaneous mutation rates and preserving genetic integrity remains incomplete. This review outlines various cellular pathways affecting mutation rates and explores the role of mutator genes and mutation-derived phenotypes, particularly prevalent in malignant tumor cells. An in-depth comprehension of mutator and antimutator activities in yeast and higher eukaryotes holds promise for effective cancer control strategies.
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Affiliation(s)
- Woo-Hyun Chung
- College of Pharmacy, Duksung Women's University, Seoul, 01369, Republic of Korea.
- Innovative Drug Center, Duksung Women's University, Seoul, 01369, Republic of Korea.
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2
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Gartner A, Engebrecht J. DNA repair, recombination, and damage signaling. Genetics 2021; 220:6522877. [PMID: 35137093 PMCID: PMC9097270 DOI: 10.1093/genetics/iyab178] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/10/2021] [Indexed: 01/09/2023] Open
Abstract
DNA must be accurately copied and propagated from one cell division to the next, and from one generation to the next. To ensure the faithful transmission of the genome, a plethora of distinct as well as overlapping DNA repair and recombination pathways have evolved. These pathways repair a large variety of lesions, including alterations to single nucleotides and DNA single and double-strand breaks, that are generated as a consequence of normal cellular function or by external DNA damaging agents. In addition to the proteins that mediate DNA repair, checkpoint pathways have also evolved to monitor the genome and coordinate the action of various repair pathways. Checkpoints facilitate repair by mediating a transient cell cycle arrest, or through initiation of cell suicide if DNA damage has overwhelmed repair capacity. In this chapter, we describe the attributes of Caenorhabditis elegans that facilitate analyses of DNA repair, recombination, and checkpoint signaling in the context of a whole animal. We review the current knowledge of C. elegans DNA repair, recombination, and DNA damage response pathways, and their role during development, growth, and in the germ line. We also discuss how the analysis of mutational signatures in C. elegans is helping to inform cancer mutational signatures in humans.
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Affiliation(s)
- Anton Gartner
- Department for Biological Sciences, IBS Center for Genomic Integrity, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea,Corresponding author: (A.G.); (J.E.)
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA,Corresponding author: (A.G.); (J.E.)
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3
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Halas A, Fijak-Moskal J, Kuberska R, Murcia Pienkowski V, Kaniak-Golik A, Pollak A, Poznanski J, Rydzanicz M, Bik-Multanowski M, Sledziewska-Gojska E, Płoski R. Developmental delay with hypotrophy associated with homozygous functionally relevant REV3L variant. J Mol Med (Berl) 2021; 99:415-423. [PMID: 33474647 DOI: 10.1007/s00109-020-02033-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/07/2020] [Accepted: 12/23/2020] [Indexed: 11/29/2022]
Abstract
REV3L encodes a catalytic subunit of DNA polymerase zeta (Pol zeta) which is essential for the tolerance of DNA damage by inducing translesion synthesis (TLS). So far, the only Mendelian disease associated with REV3L was Moebius syndrome (3 patients with dominant REV3L mutations causing monoallelic loss-of-function were reported). We describe a homozygous ultra-rare REV3L variant (T2753R) identified with whole exome sequencing in a child without Moebius syndrome but with developmental delay, hypotrophy, and dysmorphic features who was born to healthy parents (heterozygous carriers of the variant). The variant affects the amino acid adjacent to functionally important KKRY motif. By introducing an equivalent mutation (S1192R) into the REV3 gene in yeasts, we showed that, whereas it retained residual function, it caused clear dysfunction of TLS in the nucleus and instability of mitochondrial genetic information. In particular, the mutation increased UV sensitivity measured by cell survival, decreased both the spontaneous (P < 0.005) and UV-induced (P < 0.0001) mutagenesis rates of nuclear DNA and increased the UV-induced mutagenesis rates of mitochondrial DNA (P < 0.0005). We propose that our proband is the first reported case of a REV3L associated disease different from Moebius syndrome both in terms of clinical manifestations and inheritance (autosomal recessive rather than dominant). KEY MESSAGES: First description of a human recessive disorder associated with a REV3L variant. A study in yeast showed that the variant affected the enzymatic function of the protein. In particular, it caused increased UV sensitivity and abnormal mutagenesis rates.
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Affiliation(s)
- Agnieszka Halas
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Jolanta Fijak-Moskal
- Department of Medical Genetics, Jagiellonian University Medical College, 30-663, Krakow, Poland
| | - Renata Kuberska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Victor Murcia Pienkowski
- Department of Medical Genetics, Medical University of Warsaw, 02-106, Warsaw, Poland.,Ardigen, Podole 76, 30-394, Krakow, Poland
| | - Aneta Kaniak-Golik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Medical Genetics, Medical University of Warsaw, 02-106, Warsaw, Poland
| | - Jarosław Poznanski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Malgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, 02-106, Warsaw, Poland
| | | | - Ewa Sledziewska-Gojska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland.
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, 02-106, Warsaw, Poland.
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4
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Takezawa J, Shimazaki A, Takimoto H, Kajiwara K, Yamada K. A large intermediate domain of vertebrate REV3 protein is dispensable for ultraviolet-induced translesion replication. DNA Repair (Amst) 2020; 98:103031. [PMID: 33387704 DOI: 10.1016/j.dnarep.2020.103031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 11/24/2022]
Abstract
DNA polymerase ζ (pol ζ) is involved in translesion replication (translesion synthesis, TLS) and plays an essential role in embryogenesis. In adults, pol ζ triggers mutation as a result of error-prone TLS and causes carcinogenesis. The catalytic subunit of pol ζ, REV3, is evolutionarily conserved from yeast and plants to higher eukaryotes. However, the structures are notably different: unlike that in yeast REV3, a large intermediate domain is inserted in REV3 of humans and mice. The domain is mostly occupied with noncommittal structures (random coil…etc.); therefore, its role and function are yet to be resolved. Previously, we reported deficient levels of ultraviolet (UV)-induced TLS in fibroblasts derived from the Rev3-knockout mouse embryo (Rev3KO-MEF). Here, we constructed a mouse Rev3-expressing plasmid with a deleted intermediate domain (532-1793 a.a,) and transfected it into Rev3KO-MEF. The isolated stable transformants showed comparable levels of UV-sensitivity and UV-TLS activity to those in wild-type MEF, detected using an alkaline sucrose density gradient sedimentation. These results indicate that the intermediate domain is nonessential for UV-induced translesion replication in cultured mouse cells.
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Affiliation(s)
- Jun Takezawa
- Department of Genetic Biochemistry, The National Institutes of Biomedical Innovation, Health and Nutrition, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8636, Japan
| | - Anna Shimazaki
- Department of Genetic Biochemistry, The National Institutes of Biomedical Innovation, Health and Nutrition, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8636, Japan
| | - Hidemi Takimoto
- Department of Nutritional Epidemiology and Shoku-iku, The National Institutes of Biomedical Innovation, Health and Nutrition, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8636, Japan
| | | | - Kouichi Yamada
- Department of Genetic Biochemistry, The National Institutes of Biomedical Innovation, Health and Nutrition, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8636, Japan.
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5
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Abstract
Cellular DNA is constantly chemically altered by exogenous and endogenous agents. As all processes of life depend on the transmission of the genetic information, multiple biological processes exist to ensure genome integrity. Chemically damaged DNA has been linked to cancer and aging, therefore it is of great interest to map DNA damage formation and repair to elucidate the distribution of damage on a genome-wide scale. While the low abundance and inability to enzymatically amplify DNA damage are obstacles to genome-wide sequencing, new developments in the last few years have enabled high-resolution mapping of damaged bases. Recently, a number of DNA damage sequencing library construction strategies coupled to new data analysis pipelines allowed the mapping of specific DNA damage formation and repair at high and single nucleotide resolution. Strikingly, these advancements revealed that the distribution of DNA damage is heavily influenced by chromatin states and the binding of transcription factors. In the last seven years, these novel approaches have revealed new genomic maps of DNA damage distribution in a variety of organisms as generated by diverse chemical and physical DNA insults; oxidative stress, chemotherapeutic drugs, environmental pollutants, and sun exposure. Preferred sequences for damage formation and repair have been elucidated, thus making it possible to identify persistent weak spots in the genome as locations predicted to be vulnerable for mutation. As such, sequencing DNA damage will have an immense impact on our ability to elucidate mechanisms of disease initiation, and to evaluate and predict the efficacy of chemotherapeutic drugs.
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Affiliation(s)
- Cécile Mingard
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
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Meier B, Volkova NV, Gerstung M, Gartner A. Analysis of mutational signatures in C. elegans: Implications for cancer genome analysis. DNA Repair (Amst) 2020; 95:102957. [PMID: 32980770 DOI: 10.1016/j.dnarep.2020.102957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/19/2020] [Accepted: 08/22/2020] [Indexed: 01/02/2023]
Abstract
Genome integrity is constantly challenged by exogenous and endogenous insults, and mutations are associated with inherited disease and cancer. Here we summarize recent studies that utilized C. elegans whole genome next generation sequencing to experimentally determine mutational signatures associated with mutagen exposure, DNA repair deficiency or a combination of both and discuss the implications of these results for the understanding of cancer genome evolution. The experimental analysis of wild-type and DNA repair deficient nematodes propagated under unchallenged conditions over many generations revealed increased mutagenesis in approximately half of all DNA repair deficient strains, its rate, except for DNA mismatch repair, only being moderately increased. The exposure of wild-type and DNA repair defective strains to selected genotoxins, including UV-B and ionizing radiation, alkylating compounds, aristolochic acid, aflatoxin-B1, and cisplatin enabled the systematic analysis of the relative contributions of redundant repair modalities that mend DNA damage. Combining genotoxin exposure with DNA repair deficiency can manifest as altered mutation rates and/or as a change in mutational profiles, and reveals how different DNA alterations induced by one genotoxin are repaired by separate DNA repair pathways, often in a highly redundant way. Cancer genomes provide a snapshot of all mutational events that happened prior to cancer detection and sequencing, necessitating computational models to deduce mutational signatures using mathematical best fit approaches. While computationally deducing signatures from cancer genomes has been tremendously successful in associating some signatures to known mutagenic causes, many inferred signatures lack a clear link to a known mutagenic process. Moreover, analytical signatures might not reflect any distinct mutagenic processes. Nonetheless, combined effects of mutagen exposure and DNA damage-repair deficiency are also present in cancer genomes, but cannot be as easily detected owing to the unknown histories of genotoxic exposures and because biallelic in contrast to monoallelic DNA repair deficiency is rare. The impact of damage-repair interactions also manifests through selective pressure for DNA repair gene inactivation during cancer evolution. Using these considerations, we discuss a theoretical framework that explains why minute mutagenic changes, possibly too small to manifest as change in a signature, can have major effects in oncogenesis. Overall, the experimental analysis of mutational processes underscores that the interpretation of mutational signatures requires considering both the primary DNA lesion and repair status and imply that mutational signatures derived from cancer genomes may be more variable than currently anticipated.
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Affiliation(s)
- Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Scotland, UK
| | - Nadezda V Volkova
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Moritz Gerstung
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK; European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Anton Gartner
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea; Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea.
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7
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Wang F, Li P, Shao Y, Li Y, Zhang K, Li M, Wang R, Zheng S, Wang Y, Song S, Feng S, Liu F, Xiao W, Li X. Site-specific proteolytic cleavage prevents ubiquitination and degradation of human REV3L, the catalytic subunit of DNA polymerase ζ. Nucleic Acids Res 2020; 48:3619-3637. [PMID: 32064513 PMCID: PMC7144948 DOI: 10.1093/nar/gkaa096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/02/2020] [Accepted: 02/04/2020] [Indexed: 01/18/2023] Open
Abstract
REV3L, the catalytic subunit of DNA polymerase ζ (Pol ζ), is indispensable for translesion DNA synthesis, which protects cells from deleterious DNA lesions resulting from various intrinsic and environmental sources. However, REV3L lacks a proofreading exonuclease activity and consequently bypasses DNA lesions at the expense of increased mutations, which poses a severe threat to genome stability. Here we report a site-specific proteolytic event of human REV3L. We show that REV3L is cleaved by a threonine aspartase, Taspase1 (TASP1), to generate an N-terminal 70-kDa fragment (N70) and a polypeptide carrying the C-terminal polymerase catalytic domain in human cells. Strikingly, such a post-translational cleavage event plays a vital role in controlling REV3L stability by preventing ubiquitination and proteasome-mediated degradation of REV3L. Indicative of the biological importance of the above REV3L post-translational processing, cellular responses to UV and cisplatin-induced DNA lesions are markedly impaired in human HCT116 cell derivatives bearing defined point mutations in the endogenous REV3L gene that compromise REV3L cleavage. These findings establish a new paradigm in modulating the abundance of REV3L through site-specific proteolysis in human cells.
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Affiliation(s)
- Fengting Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Pan Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Yuan Shao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Yanyan Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Kai Zhang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Miaomiao Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Rong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Shuo Zheng
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Yingying Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Sen Song
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Shiguo Feng
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Fei Liu
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Wei Xiao
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
| | - Xialu Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, China
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8
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Volkova NV, Meier B, González-Huici V, Bertolini S, Gonzalez S, Vöhringer H, Abascal F, Martincorena I, Campbell PJ, Gartner A, Gerstung M. Mutational signatures are jointly shaped by DNA damage and repair. Nat Commun 2020; 11:2169. [PMID: 32358516 PMCID: PMC7195458 DOI: 10.1038/s41467-020-15912-7] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/26/2020] [Indexed: 02/08/2023] Open
Abstract
Cells possess an armamentarium of DNA repair pathways to counter DNA damage and prevent mutation. Here we use C. elegans whole genome sequencing to systematically quantify the contributions of these factors to mutational signatures. We analyse 2,717 genomes from wild-type and 53 DNA repair defective backgrounds, exposed to 11 genotoxins, including UV-B and ionizing radiation, alkylating compounds, aristolochic acid, aflatoxin B1, and cisplatin. Combined genotoxic exposure and DNA repair deficiency alters mutation rates or signatures in 41% of experiments, revealing how different DNA alterations induced by the same genotoxin are mended by separate repair pathways. Error-prone translesion synthesis causes the majority of genotoxin-induced base substitutions, but averts larger deletions. Nucleotide excision repair prevents up to 99% of point mutations, almost uniformly across the mutation spectrum. Our data show that mutational signatures are joint products of DNA damage and repair and suggest that multiple factors underlie signatures observed in cancer genomes.
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Affiliation(s)
- Nadezda V Volkova
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton, CB10, 1SD, UK
| | - Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, DD1 5EH, Scotland
| | - Víctor González-Huici
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, DD1 5EH, Scotland
- Institute for Research in Biomedicine (IRB Barcelona), Parc Científic de Barcelona, 08028, Barcelona, Spain
| | - Simone Bertolini
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, DD1 5EH, Scotland
| | - Santiago Gonzalez
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton, CB10, 1SD, UK
- Institute for Research in Biomedicine (IRB Barcelona), Parc Científic de Barcelona, 08028, Barcelona, Spain
| | - Harald Vöhringer
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton, CB10, 1SD, UK
| | - Federico Abascal
- Cancer, Ageing and Somatic Mutation, Wellcome Sanger Institute, Hinxton, CB10 1SA, UK
| | - Iñigo Martincorena
- Cancer, Ageing and Somatic Mutation, Wellcome Sanger Institute, Hinxton, CB10 1SA, UK
| | - Peter J Campbell
- Cancer, Ageing and Somatic Mutation, Wellcome Sanger Institute, Hinxton, CB10 1SA, UK
- Department of Haematology, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Haematology, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, DD1 5EH, Scotland.
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 689-798, Republic of Korea.
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, 689-798, Republic of Korea.
| | - Moritz Gerstung
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Hinxton, CB10, 1SD, UK.
- European Molecular Biology Laboratory, Genome Biology Unit, 69177, Heidelberg, Germany.
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Du H, Wang P, Wu J, He X, Wang Y. The roles of polymerases ν and θ in replicative bypass of O6- and N2-alkyl-2'-deoxyguanosine lesions in human cells. J Biol Chem 2020; 295:4556-4562. [PMID: 32098870 PMCID: PMC7135994 DOI: 10.1074/jbc.ra120.012830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/20/2020] [Indexed: 12/28/2022] Open
Abstract
Exogenous and endogenous chemicals can react with DNA to produce DNA lesions that may block DNA replication. Not much is known about the roles of polymerase (Pol) ν and Pol θ in translesion synthesis (TLS) in cells. Here we examined the functions of these two polymerases in bypassing major-groove O6-alkyl-2'-deoxyguanosine (O6-alkyl-dG) and minor-groove N2-alkyl-dG lesions in human cells, where the alkyl groups are ethyl, n-butyl (nBu), and, for O6-alkyl-dG, pyridyloxobutyl. We found that Pol ν and Pol θ promote TLS across major-groove O6-alkyl-dG lesions. O6-alkyl-dG lesions mainly induced G→A mutations that were modulated by the two TLS polymerases and the structures of the alkyl groups. Simultaneous ablation of Pol ν and Pol θ resulted in diminished mutation frequencies for all three O6-alkyl-dG lesions. Depletion of Pol ν alone reduced mutations only for O6-nBu-dG, and sole loss of Pol θ attenuated the mutation rates for O6-nBu-dG and O6-pyridyloxobutyl-dG. Replication across the two N2-alkyl-dG lesions was error-free, and Pol ν and Pol θ were dispensable for their replicative bypass. Together, our results provide critical knowledge about the involvement of Pol ν and Pol θ in bypassing alkylated guanine lesions in human cells.
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Affiliation(s)
- Hua Du
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Pengcheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Jun Wu
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Xiaomei He
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
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10
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Martin SK, Wood RD. DNA polymerase ζ in DNA replication and repair. Nucleic Acids Res 2019; 47:8348-8361. [PMID: 31410467 PMCID: PMC6895278 DOI: 10.1093/nar/gkz705] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/24/2019] [Accepted: 08/08/2019] [Indexed: 12/22/2022] Open
Abstract
Here, we survey the diverse functions of DNA polymerase ζ (pol ζ) in eukaryotes. In mammalian cells, REV3L (3130 residues) is the largest catalytic subunit of the DNA polymerases. The orthologous subunit in yeast is Rev3p. Pol ζ also includes REV7 subunits (encoded by Rev7 in yeast and MAD2L2 in mammalian cells) and two subunits shared with the replicative DNA polymerase, pol δ. Pol ζ is used in response to circumstances that stall DNA replication forks in both yeast and mammalian cells. The best-examined situation is translesion synthesis at sites of covalent DNA lesions such as UV radiation-induced photoproducts. We also highlight recent evidence that uncovers various roles of pol ζ that extend beyond translesion synthesis. For instance, pol ζ is also employed when the replisome operates sub-optimally or at difficult-to-replicate DNA sequences. Pol ζ also participates in repair by microhomology mediated break-induced replication. A rev3 deletion is tolerated in yeast but Rev3l disruption results in embryonic lethality in mice. Inactivation of mammalian Rev3l results in genomic instability and invokes cell death and senescence programs. Targeting of pol ζ function may be a useful strategy in cancer therapy, although chromosomal instability associated with pol ζ deficiency must be considered.
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Affiliation(s)
- Sara K Martin
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences
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11
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Masumura K, Toyoda-Hokaiwado N, Niimi N, Grúz P, Wada NA, Takeiri A, Jishage KI, Mishima M, Nohmi T. Limited ability of DNA polymerase kappa to suppress benzo[a]pyrene-induced genotoxicity in vivo. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:644-653. [PMID: 29076178 DOI: 10.1002/em.22146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/20/2017] [Accepted: 09/20/2017] [Indexed: 05/07/2023]
Abstract
DNA polymerase kappa (Polk) is a specialized DNA polymerase involved in translesion DNA synthesis. To understand the protective roles against genotoxins in vivo, we established inactivated Polk knock-in gpt delta (inactivated Polk KI) mice that possessed reporter genes for mutations and expressed inactive Polk. In this study, we examined genotoxicity of benzo[a]pyrene (BP) to determine whether Polk actually suppressed BP-induced genotoxicity as predicted by biochemistry and in vitro cell culture studies. Seven-week-old inactivated Polk KI and wild-type (WT) mice were treated with BP at doses of 5, 15, or 50 mg/(kg·day) for three consecutive days by intragastric gavage, and mutations in the colon and micronucleus formation in the peripheral blood were examined. Surprisingly, no differences were observed in the frequencies of mutations and micronucleus formation at 5 or 50 mg/kg doses. Inactivated Polk KI mice exhibited approximately two times higher gpt mutant frequency than did WT mice only at the 15 mg/kg dose. The frequency of micronucleus formation was slightly higher in inactivated Polk KI than in WT mice at the same dose, but it was statistically insignificant. The results suggest that Polk has a limited ability to suppress BP-induced genotoxicity in the colon and bone marrow and also that the roles of specialized DNA polymerases in mutagenesis and carcinogenesis should be examined not only by in vitro assays but also by in vivo mouse studies. We also report the spontaneous mutagenesis in inactivated Polk KI mice at young and old ages. Environ. Mol. Mutagen. 58:644-653, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Naomi Toyoda-Hokaiwado
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Naoko Niimi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Petr Grúz
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Naoko A Wada
- Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka, 412-8513, Japan
| | - Akira Takeiri
- Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka, 412-8513, Japan
| | - Kou-Ichi Jishage
- Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka, 412-8513, Japan
| | - Masayuki Mishima
- Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka, 412-8513, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
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12
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PARP1 protects from benzo[a]pyrene diol epoxide-induced replication stress and mutagenicity. Arch Toxicol 2017; 92:1323-1340. [PMID: 29196784 PMCID: PMC5866831 DOI: 10.1007/s00204-017-2115-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023]
Abstract
Poly(ADP-ribosyl)ation (PARylation) is a complex and reversible posttranslational modification catalyzed by poly(ADP-ribose)polymerases (PARPs), which orchestrates protein function and subcellular localization. The function of PARP1 in genotoxic stress response upon induction of oxidative DNA lesions and strand breaks is firmly established, but its role in the response to chemical-induced, bulky DNA adducts is understood incompletely. To address the role of PARP1 in the response to bulky DNA adducts, we treated human cancer cells with benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide (BPDE), which represents the active metabolite of the environmental carcinogen benzo[a]pyrene [B(a)P], in nanomolar to low micromolar concentrations. Using a highly sensitive LC-MS/MS method, we revealed that BPDE induces cellular PAR formation in a time- and dose-dependent manner. Consistently, PARP1 activity significantly contributed to BPDE-induced genotoxic stress response. On one hand, PARP1 ablation rescued BPDE-induced NAD+ depletion and protected cells from BPDE-induced short-term toxicity. On the other hand, strong sensitization effects of PARP inhibition and PARP1 ablation were observed in long-term clonogenic survival assays. Furthermore, PARP1 ablation significantly affected BPDE-induced S- and G2-phase transitions. Together, these results point towards unresolved BPDE-DNA lesions triggering replicative stress. In line with this, BPDE exposure resulted in enhanced formation and persistence of DNA double-strand breaks in PARP1-deficient cells as evaluated by microscopic co-localization studies of 53BP1 and γH2A.X foci. Consistently, an HPRT mutation assay revealed that PARP inhibition potentiated the mutagenicity of BPDE. In conclusion, this study demonstrates a profound role of PARylation in BPDE-induced genotoxic stress response with significant functional consequences and potential relevance with regard to B[a]P-induced cancer risks.
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13
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Gahlon HL, Romano LJ, Rueda D. Influence of DNA Lesions on Polymerase-Mediated DNA Replication at Single-Molecule Resolution. Chem Res Toxicol 2017; 30:1972-1983. [PMID: 29020440 DOI: 10.1021/acs.chemrestox.7b00224] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Faithful replication of DNA is a critical aspect in maintaining genome integrity. DNA polymerases are responsible for replicating DNA, and high-fidelity polymerases do this rapidly and at low error rates. Upon exposure to exogenous or endogenous substances, DNA can become damaged and this can alter the speed and fidelity of a DNA polymerase. In this instance, DNA polymerases are confronted with an obstacle that can result in genomic instability during replication, for example, by nucleotide misinsertion or replication fork collapse. It is important to know how DNA polymerases respond to damaged DNA substrates to understand the mechanism of mutagenesis and chemical carcinogenesis. Single-molecule techniques have helped to improve our current understanding of DNA polymerase-mediated DNA replication, as they enable the dissection of mechanistic details that can otherwise be lost in ensemble-averaged experiments. These techniques have also been used to gain a deeper understanding of how single DNA polymerases behave at the site of the damage in a DNA substrate. In this review, we evaluate single-molecule studies that have examined the interaction between DNA polymerases and damaged sites on a DNA template.
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Affiliation(s)
- Hailey L Gahlon
- Molecular Virology, Department of Medicine, Imperial College London , Du Cane Road, London W12 0NN, U.K.,Single Molecule Imaging Group, MRC London Institute of Medical Sciences , Du Cane Road, London W12 0NN, U.K
| | - Louis J Romano
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - David Rueda
- Molecular Virology, Department of Medicine, Imperial College London , Du Cane Road, London W12 0NN, U.K.,Single Molecule Imaging Group, MRC London Institute of Medical Sciences , Du Cane Road, London W12 0NN, U.K
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14
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Kochenova OV, Bezalel-Buch R, Tran P, Makarova AV, Chabes A, Burgers PMJ, Shcherbakova PV. Yeast DNA polymerase ζ maintains consistent activity and mutagenicity across a wide range of physiological dNTP concentrations. Nucleic Acids Res 2017; 45:1200-1218. [PMID: 28180291 PMCID: PMC5388397 DOI: 10.1093/nar/gkw1149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/31/2016] [Accepted: 11/02/2016] [Indexed: 11/12/2022] Open
Abstract
In yeast, dNTP pools expand drastically during DNA damage response. We show that similar dNTP elevation occurs in strains, in which intrinsic replisome defects promote the participation of error-prone DNA polymerase ζ (Polζ) in replication of undamaged DNA. To understand the significance of dNTP pools increase for Polζ function, we studied the activity and fidelity of four-subunit Polζ (Polζ4) and Polζ4-Rev1 (Polζ5) complexes in vitro at ‘normal S-phase’ and ‘damage-response’ dNTP concentrations. The presence of Rev1 inhibited the activity of Polζ and greatly increased the rate of all three ‘X-dCTP’ mispairs, which Polζ4 alone made extremely inefficiently. Both Polζ4 and Polζ5 were most promiscuous at G nucleotides and frequently generated multiple closely spaced sequence changes. Surprisingly, the shift from ‘S-phase’ to ‘damage-response’ dNTP levels only minimally affected the activity, fidelity and error specificity of Polζ complexes. Moreover, Polζ-dependent mutagenesis triggered by replisome defects or UV irradiation in vivo was not decreased when dNTP synthesis was suppressed by hydroxyurea, indicating that Polζ function does not require high dNTP levels. The results support a model wherein dNTP elevation is needed to facilitate non-mutagenic tolerance pathways, while Polζ synthesis represents a unique mechanism of rescuing stalled replication when dNTP supply is low.
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Affiliation(s)
- Olga V Kochenova
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rachel Bezalel-Buch
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Phong Tran
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Alena V Makarova
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Peter M J Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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15
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Suzuki T, Grúz P, Honma M, Adachi N, Nohmi T. The role of DNA polymerase ζ in translesion synthesis across bulky DNA adducts and cross-links in human cells. Mutat Res 2016; 791-792:35-41. [PMID: 27591392 DOI: 10.1016/j.mrfmmm.2016.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 08/17/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Translesion DNA synthesis (TLS) is a cellular defense mechanism against genotoxins. Defects or mutations in specialized DNA polymerases (Pols) involved in TLS are believed to result in hypersensitivity to various genotoxic stresses. Here, DNA polymerase ζ (Pol ζ)-deficient (KO: knockout) and Pol ζ catalytically dead (CD) human cells were established and their sensitivity towards cytotoxic activities of various genotoxins was examined. The CD cells were engineered by altering the DNA sequence encoding two amino acids essential for the catalytic activity of Pol ζ, i.e., D2781 and D2783, to alanines. Both Pol ζ KO and CD cells displayed a prolonged cell cycle and higher incidence of micronuclei formation than the wild-type (WT) cells in the absence of exogenous genotoxic treatments, and the order of abnormality was CD>KO>WT cells. Both KO and CD cells exhibited higher sensitivity towards the killing effects of benzo[a]pyrene diol epoxide, mitomycin C, potassium bromate, N-methyl-N'-nitro-N-nitrosoguanidine, and ultraviolet C irradiation than WT cells, and there were no differences between the sensitivities of KO and CD cells. Interestingly, neither KO nor CD cells were sensitive to the cytotoxic effects of hydrogen peroxide. Since KO and CD cells displayed similar sensitivities to the genotoxins, we employed only KO cells to further examine their sensitivity to other genotoxic agents. KO cells were more sensitive to the cytotoxicity of 4-nitroquinoline N-oxide, styrene oxide, cisplatin, methyl methanesulfonate, and ethyl methanesulfonate than WT cells. However, the KO cells displayed sensitivity camptothecin, etoposide, bleomycin, hydroxyurea, crotonealdehyde, and methylglyoxal in a manner similar to the WT cells. Our results suggest that Pol ζ plays an important role in the protection of human cells by carrying out TLS across bulky DNA adducts and cross-links, but has no or limited role in the protection against strand-breaks in DNA.
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Affiliation(s)
- Tetsuya Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
| | - Petr Grúz
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Noritaka Adachi
- Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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16
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Sensitivity of human cells expressing low-fidelity or weak-catalytic-activity variants of DNA polymerase ζ to genotoxic stresses. DNA Repair (Amst) 2016; 45:34-43. [DOI: 10.1016/j.dnarep.2016.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/13/2016] [Accepted: 06/04/2016] [Indexed: 01/22/2023]
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17
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Korzhnev DM, Hadden MK. Targeting the Translesion Synthesis Pathway for the Development of Anti-Cancer Chemotherapeutics. J Med Chem 2016; 59:9321-9336. [PMID: 27362876 DOI: 10.1021/acs.jmedchem.6b00596] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Human cells possess tightly controlled mechanisms to rescue DNA replication following DNA damage caused by environmental and endogenous carcinogens using a set of low-fidelity translesion synthesis (TLS) DNA polymerases. These polymerases can copy over replication blocking DNA lesions while temporarily leaving them unrepaired, preventing cell death at the expense of increasing mutation rates and contributing to the onset and progression of cancer. In addition, TLS has been implicated as a major cellular mechanism promoting acquired resistance to genotoxic chemotherapy. Owing to its central role in mutagenesis and cell survival after DNA damage, inhibition of the TLS pathway has emerged as a potential target for the development of anticancer agents. This review will recap our current understanding of the structure and regulation of DNA polymerase complexes that mediate TLS and describe how this knowledge is beginning to translate into the development of small molecule TLS inhibitors.
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Affiliation(s)
- Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center , Farmington, Connecticut 06030, United States
| | - M Kyle Hadden
- Department of Pharmaceutical Sciences, University of Connecticut , 69 North Eagleville Road, Unit 3092, Storrs, Connecticut 06269, United States
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18
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Singh B, Li X, Owens KM, Vanniarajan A, Liang P, Singh KK. Human REV3 DNA Polymerase Zeta Localizes to Mitochondria and Protects the Mitochondrial Genome. PLoS One 2015; 10:e0140409. [PMID: 26462070 PMCID: PMC4604079 DOI: 10.1371/journal.pone.0140409] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/24/2015] [Indexed: 12/29/2022] Open
Abstract
To date, mitochondrial DNA polymerase γ (POLG) is the only polymerase known to be present in mammalian mitochondria. A dogma in the mitochondria field is that there is no other polymerase present in the mitochondria of mammalian cells. Here we demonstrate localization of REV3 DNA polymerase in the mammalian mitochondria. We demonstrate localization of REV3 in the mitochondria of mammalian tissue as well as cell lines. REV3 associates with POLG and mitochondrial DNA and protects the mitochondrial genome from DNA damage. Inactivation of Rev3 leads to reduced mitochondrial membrane potential, reduced OXPHOS activity, and increased glucose consumption. Conversely, inhibition of the OXPHOS increases expression of Rev3. Rev3 expression is increased in human primary breast tumors and breast cancer cell lines. Inactivation of Rev3 decreases cell migration and invasion, and localization of Rev3 in mitochondria increases survival and the invasive potential of cancer cells. Taken together, we demonstrate that REV3 functions in mammalian mitochondria and that mitochondrial REV3 is associated with the tumorigenic potential of cells.
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Affiliation(s)
- Bhupendra Singh
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Xiurong Li
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Kjerstin M. Owens
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Ayyasamy Vanniarajan
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharine’s, Ontario, Canada
| | - Keshav K. Singh
- Departments of Genetics, Pathology, Environmental Health, Center for Free Radical Biology, Center for Aging and UAB Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Birmingham Veterans Affairs Medical Center, Birmingham, Alabama, United States of America
- * E-mail:
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19
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REV3L, a promising target in regulating the chemosensitivity of cervical cancer cells. PLoS One 2015; 10:e0120334. [PMID: 25781640 PMCID: PMC4364373 DOI: 10.1371/journal.pone.0120334] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/29/2015] [Indexed: 12/14/2022] Open
Abstract
REV3L, the catalytic subunit of DNA Polymerase ζ (Polζ), plays a significant role in the DNA damage tolerance mechanism of translesion synthesis (TLS). The role of REV3L in chemosensitivity of cervical cancer needs exploration. In the present study, we evaluated the expression of the Polζ protein in paraffin-embedded tissues using immunohistochemistry and found that the expression of Polζ in cervical cancer tissues was higher than that in normal tissues. We then established some cervical cancer cell lines with REV3L suppression or overexpression. Depletion of REV3L suppresses cell proliferation and colony formation of cervical cancer cells through G1 arrest, and REV3L promotes cell proliferation and colony formation of cervical cancer cells by promoting G1 phase to S phase transition. The suppression of REV3L expression enhanced the sensitivity of cervical cancer cells to cisplatin, and the overexpression of REV3L conferred resistance to cisplatin as evidenced by the alteration of apoptosis rates, and significantly expression level changes of anti-apoptotic proteins B-cell lymphoma 2 (Bcl-2), myeloid cell leukemia sequence 1 (Mcl-1) and B-cell lymphoma-extra large (Bcl-xl) and proapoptotic Bcl-2-associated x protein (Bax). Our data suggest that REV3L plays an important role in regulating cervical cancer cellular response to cisplatin, and thus targeting REV3L may be a promising way to alter chemosensitivity in cervical cancer patients.
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20
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Makarova AV, Burgers PM. Eukaryotic DNA polymerase ζ. DNA Repair (Amst) 2015; 29:47-55. [PMID: 25737057 DOI: 10.1016/j.dnarep.2015.02.012] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 12/16/2022]
Abstract
This review focuses on eukaryotic DNA polymerase ζ (Pol ζ), the enzyme responsible for the bulk of mutagenesis in eukaryotic cells in response to DNA damage. Pol ζ is also responsible for a large portion of mutagenesis during normal cell growth, in response to spontaneous damage or to certain DNA structures and other blocks that stall DNA replication forks. Novel insights in mutagenesis have been derived from recent advances in the elucidation of the subunit structure of Pol ζ. The lagging strand DNA polymerase δ shares the small Pol31 and Pol32 subunits with the Rev3-Rev7 core assembly giving a four subunit Pol ζ complex that is the active form in mutagenesis. Furthermore, Pol ζ forms essential interactions with the mutasome assembly factor Rev1 and with proliferating cell nuclear antigen (PCNA). These interactions are modulated by posttranslational modifications such as ubiquitination and phosphorylation that enhance translesion synthesis (TLS) and mutagenesis.
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Affiliation(s)
- Alena V Makarova
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Institute of Molecular Genetics, Russian Academy of Sciences (IMG RAS), Kurchatov Sq. 2, Moscow 123182, Russia
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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21
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Jansen JG, Tsaalbi-Shtylik A, de Wind N. Roles of mutagenic translesion synthesis in mammalian genome stability, health and disease. DNA Repair (Amst) 2015; 29:56-64. [PMID: 25655219 DOI: 10.1016/j.dnarep.2015.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/22/2014] [Accepted: 01/07/2015] [Indexed: 01/08/2023]
Abstract
Most spontaneous and DNA damage-induced nucleotide substitutions in eukaryotes depend on translesion synthesis polymerases Rev1 and Pol ζ, the latter consisting of the catalytic subunit Rev3 and the accessory protein Rev7. Here we review the regulation, and the biochemical and cellular functions, of Rev1/Pol ζ-dependent translesion synthesis. These are correlated with phenotypes of mouse models with defects in Rev1, Rev3 or Rev7. The data indicate that Rev1/Pol ζ-mediated translesion synthesis is important for adaptive immunity while playing paradoxical roles in oncogenesis. On the other hand, by enabling the replication of endogenously damaged templates, Rev1/Pol ζ -dependent translesion synthesis protects stem cells, thereby preventing features of ageing. In conclusion, Rev1/Pol ζ-dependent translesion synthesis at DNA helix-distorting nucleotide lesions orchestrates pleiotropic responses that determine organismal fitness and disease.
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Affiliation(s)
- Jacob G Jansen
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands
| | - Anastasia Tsaalbi-Shtylik
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands
| | - Niels de Wind
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands.
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22
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Genomic assay reveals tolerance of DNA damage by both translesion DNA synthesis and homology-dependent repair in mammalian cells. Proc Natl Acad Sci U S A 2013; 110:E1462-9. [PMID: 23530190 DOI: 10.1073/pnas.1216894110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA lesions can block replication forks and lead to the formation of single-stranded gaps. These replication complications are mitigated by DNA damage tolerance mechanisms, which prevent deleterious outcomes such as cell death, genomic instability, and carcinogenesis. The two main tolerance strategies are translesion DNA synthesis (TLS), in which low-fidelity DNA polymerases bypass the blocking lesion, and homology-dependent repair (HDR; postreplication repair), which is based on the homologous sister chromatid. Here we describe a unique high-resolution method for the simultaneous analysis of TLS and HDR across defined DNA lesions in mammalian genomes. The method is based on insertion of plasmids carrying defined site-specific DNA lesions into mammalian chromosomes, using phage integrase-mediated integration. Using this method we show that mammalian cells use HDR to tolerate DNA damage in their genome. Moreover, analysis of the tolerance of the UV light-induced 6-4 photoproduct, the tobacco smoke-induced benzo[a]pyrene-guanine adduct, and an artificial trimethylene insert shows that each of these three lesions is tolerated by both TLS and HDR. We also determined the specificity of nucleotide insertion opposite these lesions during TLS in human genomes. This unique method will be useful in elucidating the mechanism of DNA damage tolerance in mammalian chromosomes and their connection to pathological processes such as carcinogenesis.
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23
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Dual role for mammalian DNA polymerase ζ in maintaining genome stability and proliferative responses. Proc Natl Acad Sci U S A 2013; 110:E687-96. [PMID: 23386725 DOI: 10.1073/pnas.1217425110] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA polymerase ζ (polζ) is critical for bypass of DNA damage and the associated mutagenesis, but also has unique functions in mammals. It is required for embryonic development and for viability of hematopoietic cells, but, paradoxically, skin epithelia appear to survive polζ deletion. We wished to determine whether polζ functions in a tissue-specific manner and how polζ status influences skin tumorigenesis. Mice were produced in which Rev3L (the catalytic subunit of polζ) was deleted in tissues expressing keratin 5. Efficient epidermal deletion of Rev3L was tolerated but led to skin and hair abnormalities, accompanied by evidence of DNA breaks. Unchallenged mice developed tumors in keratin 5-expressing tissues with age, consistent with the chromosomal instability accompanying a polζ defect. Unexpectedly, mice with the Rev3L deletion were much more sensitive to UVB radiation than mice defective in other DNA repair genes. Following irradiation, polζ-defective mice failed to mount skin-regenerative responses and responded to stress by mobilizing melanocytes to the epidermis. However, they did not develop skin tumors after chronic UVB irradiation. To determine the proliferative potential of polζ-deficient skin epithelia, keratinocytes were isolated and examined. These keratinocytes harbored chromosomal gaps and breaks and exhibited a striking proliferation defect. These results can be unified by a model in which slowly dividing cells accumulate replication-associated DNA breaks but otherwise survive Rev3L deletion, but functional polζ is essential for responses requiring rapid proliferation, both in cell culture and in vivo. The results reveal a biological role for mammalian polζ in tolerating DNA damage and enabling proliferative responses in vivo.
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24
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Waisertreiger ISR, Liston VG, Menezes MR, Kim HM, Lobachev KS, Stepchenkova EI, Tahirov TH, Rogozin IB, Pavlov YI. Modulation of mutagenesis in eukaryotes by DNA replication fork dynamics and quality of nucleotide pools. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:699-724. [PMID: 23055184 PMCID: PMC3893020 DOI: 10.1002/em.21735] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 06/01/2023]
Abstract
The rate of mutations in eukaryotes depends on a plethora of factors and is not immediately derived from the fidelity of DNA polymerases (Pols). Replication of chromosomes containing the anti-parallel strands of duplex DNA occurs through the copying of leading and lagging strand templates by a trio of Pols α, δ and ϵ, with the assistance of Pol ζ and Y-family Pols at difficult DNA template structures or sites of DNA damage. The parameters of the synthesis at a given location are dictated by the quality and quantity of nucleotides in the pools, replication fork architecture, transcription status, regulation of Pol switches, and structure of chromatin. The result of these transactions is a subject of survey and editing by DNA repair.
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Affiliation(s)
- Irina S.-R. Waisertreiger
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Victoria G. Liston
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Miriam R. Menezes
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Hyun-Min Kim
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Kirill S. Lobachev
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Elena I. Stepchenkova
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
- Saint Petersburg Branch of Vavilov Institute of General Genetics, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
- Department of Genetics, Saint Petersburg University, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
| | - Tahir H. Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
| | - Igor B. Rogozin
- National Center for Biotechnology Information NLM, National Institutes of Health, Bethesda, MD 20894, U.S.A
- Institute of Cytology and Genetics, 630090 Novosibirsk, Russia
| | - Youri. I. Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, ESH 7009, 986805 Nebraska Medical Center, Omaha, NE 68198-6805, U.S.A
- Department of Genetics, Saint Petersburg University, Universitetskaya emb. 7/9, St Petersburg, 199034, Russia
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25
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Sharma S, Helchowski CM, Canman CE. The roles of DNA polymerase ζ and the Y family DNA polymerases in promoting or preventing genome instability. Mutat Res 2012. [PMID: 23195997 DOI: 10.1016/j.mrfmmm.2012.11.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cancer cells display numerous abnormal characteristics which are initiated and maintained by elevated mutation rates and genome instability. Chromosomal DNA is continuously surveyed for the presence of damage or blocked replication forks by the DNA Damage Response (DDR) network. The DDR is complex and includes activation of cell cycle checkpoints, DNA repair, gene transcription, and induction of apoptosis. Duplicating a damaged genome is associated with elevated risks to fork collapse and genome instability. Therefore, the DNA damage tolerance (DDT) pathway is also employed to enhance survival and involves the recruitment of translesion DNA synthesis (TLS) polymerases to sites of replication fork blockade or single stranded DNA gaps left after the completion of replication in order to restore DNA to its double stranded form before mitosis. TLS polymerases are specialized for inserting nucleotides opposite DNA adducts, abasic sites, or DNA crosslinks. By definition, the DDT pathway is not involved in the actual repair of damaged DNA, but provides a mechanism to tolerate DNA lesions during replication thereby increasing survival and lessening the chance for genome instability. However this may be associated with increased mutagenesis. In this review, we will describe the specialized functions of Y family polymerases (Rev1, Polη, Polι and Polκ) and DNA polymerase ζ in lesion bypass, mutagenesis, and prevention of genome instability, the latter due to newly appreciated roles in DNA repair. The recently described role of the Fanconi anemia pathway in regulating Rev1 and Polζ-dependent TLS is also discussed in terms of their involvement in TLS, interstrand crosslink repair, and homologous recombination.
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Affiliation(s)
- Shilpy Sharma
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Corey M Helchowski
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Christine E Canman
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, United States.
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Inhibition of REV3 expression induces persistent DNA damage and growth arrest in cancer cells. Neoplasia 2012; 13:961-70. [PMID: 22028621 DOI: 10.1593/neo.11828] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/23/2011] [Accepted: 08/26/2011] [Indexed: 02/02/2023] Open
Abstract
REV3 is the catalytic subunit of DNA translesion synthesis polymerase ζ. Inhibition of REV3 expression increases the sensitivity of human cells to a variety of DNA-damaging agents and reduces the formation of resistant cells. Surprisingly, we found that short hairpin RNA-mediated depletion of REV3 per se suppresses colony formation of lung (A549, Calu-3), breast (MCF-7, MDA-MB-231), mesothelioma (IL45 and ZL55), and colon (HCT116 +/-p53) tumor cell lines, whereas control cell lines (AD293, LP9-hTERT) and the normal mesothelial primary culture (SDM104) are less affected. Inhibition of REV3 expression in cancer cells leads to an accumulation of persistent DNA damage as indicated by an increase in phospho-ATM, 53BP1, and phospho-H2AX foci formation, subsequently leading to the activation of the ATM-dependent DNA damage response cascade. REV3 depletion in p53-proficient cancer cell lines results in a G(1) arrest and induction of senescence as indicated by the accumulation of p21 and an increase in senescence-associated β-galactosidase activity. In contrast, inhibition of REV3 expression in p53-deficient cells results in growth inhibition and a G(2)/M arrest. A small fraction of the p53-deficient cancer cells can overcome the G(2)/M arrest, which results in mitotic slippage and aneuploidy. Our findings reveal that REV3 depletion per se suppresses growth of cancer cell lines from different origin, whereas control cell lines and a mesothelial primary culture were less affected. Thus, our findings indicate that depletion of REV3 not only can amend cisplatin-based cancer therapy but also can be applied for susceptible cancers as a potential monotherapy.
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Lange SS, Wittschieben JP, Wood RD. DNA polymerase zeta is required for proliferation of normal mammalian cells. Nucleic Acids Res 2012; 40:4473-82. [PMID: 22319213 PMCID: PMC3378892 DOI: 10.1093/nar/gks054] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Unique among translesion synthesis (TLS) DNA polymerases, pol ζ is essential during embryogenesis. To determine whether pol ζ is necessary for proliferation of normal cells, primary mouse fibroblasts were established in which Rev3L could be conditionally inactivated by Cre recombinase. Cells were grown in 2% O2 to prevent oxidative stress-induced senescence. Cells rapidly became senescent or apoptotic and ceased growth within 3–4 population doublings. Within one population doubling following Rev3L deletion, DNA double-strand breaks and chromatid aberrations were found in 30–50% of cells. These breaks were replication dependent, and found in G1 and G2 phase cells. Double-strand breaks were reduced when cells were treated with the reactive oxygen species scavenger N-acetyl-cysteine, but this did not rescue the cell proliferation defect, indicating that several classes of endogenously formed DNA lesions require Rev3L for tolerance or repair. T-antigen immortalization of cells allowed cell growth. In summary, even in the absence of external challenges to DNA, pol ζ is essential for preventing replication-dependent DNA breaks in every division of normal mammalian cells. Loss of pol ζ in slowly proliferating mouse cells in vivo may allow accumulation of chromosomal aberrations that could lead to tumorigenesis. Pol ζ is unique amongst TLS polymerases for its essential role in cell proliferation.
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Affiliation(s)
- Sabine S Lange
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center Science Park, and the Graduate School of Biomedical Sciences at Houston, Smithville Texas, P.O. Box 389, Smithville, TX 78957, USA
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Takezawa J, Aiba N, Kajiwara K, Yamada K. Caffeine abolishes the ultraviolet-induced REV3 translesion replication pathway in mouse cells. Int J Mol Sci 2011; 12:8513-29. [PMID: 22272088 PMCID: PMC3257085 DOI: 10.3390/ijms12128513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/08/2011] [Accepted: 11/17/2011] [Indexed: 11/26/2022] Open
Abstract
When a replicative DNA polymerase stalls upon encountering a photoproduct on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion. Using an alkaline sucrose density gradient sedimentation technique, we previously classified this process termed UV-induced translesion replication (UV-TLS) into two types. In human cancer cells or xeroderma pigmentosum variant (XP-V) cells, UV-TLS was inhibited by caffeine or proteasome inhibitors. However, in normal human cells, the process was insensitive to these reagents. Reportedly, in yeast or mammalian cells, REV3 protein (a catalytic subunit of DNA polymerase ζ) is predominantly involved in the former type of TLS. Here, we studied UV-TLS in fibroblasts derived from the Rev3-knockout mouse embryo (Rev3KO-MEF). In the wild-type MEF, UV-TLS was slow (similar to that of human cancer cells or XP-V cells), and was abolished by caffeine or MG-262. In 2 cell lines of Rev3KO-MEF (Rev3−/−p53−/−), UV-TLS was not observed. In p53KO-MEF, which is a strict control for Rev3KO-MEF, the UV-TLS response was similar to that of the wild-type. Introduction of the Rev3 expression plasmid into Rev3KO-MEF restored the UV-TLS response in selected stable transformants. In some transformants, viability to UV was the same as that in the wild-type, and the death rate was increased by caffeine. Our findings indicate that REV3 is predominantly involved in UV-TLS in mouse cells, and that the REV3 translesion pathway is suppressed by caffeine or proteasome inhibitors.
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Affiliation(s)
- Jun Takezawa
- Division of Genetic Biochemistry, The National Institute of Health and Nutrition, Shinjuku-ku, Tokyo 162-8636, Japan; E-Mail: (J.T.)
| | - Naomi Aiba
- Division of Genetic Biochemistry, The National Institute of Health and Nutrition, Shinjuku-ku, Tokyo 162-8636, Japan; E-Mail: (J.T.)
| | - Kagemasa Kajiwara
- School of Medicine, Tokai University, Isehara-shi, Kanagawa-ken 259-1193, Japan
| | - Kouichi Yamada
- Division of Genetic Biochemistry, The National Institute of Health and Nutrition, Shinjuku-ku, Tokyo 162-8636, Japan; E-Mail: (J.T.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-3-3203-5723; Fax: +81-3-3203-0335
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Knobel PA, Marti TM. Translesion DNA synthesis in the context of cancer research. Cancer Cell Int 2011; 11:39. [PMID: 22047021 PMCID: PMC3224763 DOI: 10.1186/1475-2867-11-39] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 11/02/2011] [Indexed: 11/17/2022] Open
Abstract
During cell division, replication of the genomic DNA is performed by high-fidelity DNA polymerases but these error-free enzymes can not synthesize across damaged DNA. Specialized DNA polymerases, so called DNA translesion synthesis polymerases (TLS polymerases), can replicate damaged DNA thereby avoiding replication fork breakdown and subsequent chromosomal instability. We focus on the involvement of mammalian TLS polymerases in DNA damage tolerance mechanisms. In detail, we review the discovery of TLS polymerases and describe the molecular features of all the mammalian TLS polymerases identified so far. We give a short overview of the mechanisms that regulate the selectivity and activity of TLS polymerases. In addition, we summarize the current knowledge how different types of DNA damage, relevant either for the induction or treatment of cancer, are bypassed by TLS polymerases. Finally, we elucidate the relevance of TLS polymerases in the context of cancer therapy.
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Affiliation(s)
- Philip A Knobel
- Laboratory of Molecular Oncology, Clinic and Polyclinic of Oncology, University Hospital Zürich, Häldeliweg 4, CH-8044 Zürich, Switzerland.
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30
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Andersen PL, Xu F, Ziola B, McGregor WG, Xiao W. Sequential assembly of translesion DNA polymerases at UV-induced DNA damage sites. Mol Biol Cell 2011; 22:2373-83. [PMID: 21551069 PMCID: PMC3128538 DOI: 10.1091/mbc.e10-12-0938] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Three endogenous translesion DNA polymerases are sequentially assembled to the stalled
replication site in the form of UV-induced nuclear foci. Detailed supporting evidence is given for the polymerase switch model. In response to DNA damage such as from UV irradiation, mammalian Y-family translesion synthesis (TLS) polymerases Polη and Rev1 colocalize with proliferating cell nuclear antigen at nuclear foci, presumably representing stalled replication sites. However, it is unclear whether the localization of one polymerase is dependent on another. Furthermore, there is no report on the in vivo characterization of the Rev3 catalytic subunit of the B-family TLS polymerase Polζ. Here we describe the detection of endogenous human Polη, Rev1, and Rev3 by immunocytochemistry using existing or newly created antibodies, as well as various means of inhibiting their expression, which allows us to examine the dynamics of endogenous TLS polymerases in response to UV irradiation. It is found that Rev1 and Polη are independently recruited to the nuclear foci, whereas the Rev3 nuclear focus formation requires Rev1 but not Polη. In contrast, neither Rev1 nor Polη recruitment requires Rev3. To further support these conclusions, we find that simultaneous suppression of Polη and Rev3 results in an additive cellular sensitivity to UV irradiation. These observations suggest a cooperative and sequential assembly of TLS polymerases in response to DNA damage. They also support and extend the current polymerase switch model.
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Affiliation(s)
- Parker L Andersen
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, S7N 5E5, Canada
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Abstract
There are 15 different DNA polymerases encoded in mammalian genomes, which are specialized for replication, repair or the tolerance of DNA damage. New evidence is emerging for lesion-specific and tissue-specific functions of DNA polymerases. Many point mutations that occur in cancer cells arise from the error-generating activities of DNA polymerases. However, the ability of some of these enzymes to bypass DNA damage may actually defend against chromosome instability in cells, and at least one DNA polymerase, Pol ζ, is a suppressor of spontaneous tumorigenesis. Because DNA polymerases can help cancer cells tolerate DNA damage, some of these enzymes might be viable targets for therapeutic strategies.
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Affiliation(s)
| | | | - Richard D. Wood
- Correspondence to: 1808 Park Road 1C, P.O. Box 389, Smithville, TX, USA, 78957 Tel: (512) 237-9431 Fax: (512) 237-6532
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Neal JA, Fletcher KL, McCormick JJ, Maher VM. The role of hRev7, the accessory subunit of hPolζ, in translesion synthesis past DNA damage induced by benzo[a]pyrene diol epoxide (BPDE). BMC Cell Biol 2010; 11:97. [PMID: 21143968 PMCID: PMC3017036 DOI: 10.1186/1471-2121-11-97] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 12/10/2010] [Indexed: 11/10/2022] Open
Abstract
Background DNA polymerase zeta (Polζ) is a specialized DNA polymerase that, unlike classical replicative polymerases, is capable of replicating past DNA lesions, i.e. of performing translesion synthesis (TLS). The catalytic subunit of hPolζ, hRev3, has been shown to play a critical role in DNA damage-induced mutagenesis in human cells, but less is known about the role of hRev7, the accessory subunit of hPolζ, in such mutagenesis. To address this question, we recently generated human fibroblasts with very significantly reduced levels of hRev7 protein and demonstrated that hRev7 is required to protect cells from ultraviolet(254 nm) (UV) radiation-induced cytotoxicity and mutagenesis (McNally et al., DNA Repair 7 (2008) 597-604). The goal of the present study was to determine whether hRev7 is similarly involved in the tolerance of DNA damage induced by benzo[a]pyrene diol epoxide (BPDE), the reactive form of the widespread environmental carcinogen benzo[a]pyrene. Methods To determine whether hRev7 also plays a role in protecting human cells from the cytotoxicity and mutagenesis induced by benzo[a]pyrene diol epoxide (BPDE), cell strains with reduced hRev7 were compared to their parental strain and a vector control strain for the effect of BPDE on cell survival, induction of mutations, and the ability to progress through the cell cycle. Results The results show that cell strains with reduced hRev7 are more sensitive to the cytotoxic effect of BPDE than the control strains, and progress through S-phase at a slower rate than the control cells following BPDE treatment, indicating that hRev7, and likely hPolζ, is required for efficient bypass of BPDE-induced DNA lesions. However, neither the frequency nor kinds of mutations induced by BPDE in cells with reduced hRev7 differ significantly from those induced in the control strains, suggesting that hPolζ is not essential for inserting nucleotides opposite BPDE-induced DNA damage. Conclusions Taken together, our results which show that hRev7 is required for TLS past BPDE-induced DNA lesions but that it is not essential for inserting nucleotides opposite such lesions suggest a role for hPolζ in the extension step of translesion synthesis.
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Affiliation(s)
- Jessica A Neal
- Carcinogenesis Laboratory, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302, USA
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Takezawa J, Ishimi Y, Aiba N, Yamada K. Rev1, Rev3, or Rev7 siRNA Abolishes Ultraviolet Light-Induced Translesion Replication in HeLa Cells: A Comprehensive Study Using Alkaline Sucrose Density Gradient Sedimentation. J Nucleic Acids 2010; 2010:750296. [PMID: 21151666 PMCID: PMC2997509 DOI: 10.4061/2010/750296] [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] [Received: 05/14/2010] [Revised: 07/13/2010] [Accepted: 09/17/2010] [Indexed: 01/04/2023] Open
Abstract
When a replicative DNA polymerase stalls upon encountering a lesion on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion, extend by a few nucleotides, and dissociate from the 3'-OH. The replicative polymerase then resumes DNA synthesis. This process, termed translesion replication (TLS) or replicative bypass, may involve at least five different polymerases in mammals, although the participating polymerases and their roles have not been entirely characterized. Using siRNAs originally designed and an alkaline sucrose density gradient sedimentation technique, we verified the involvement of several polymerases in ultraviolet (UV) light-induced TLS in HeLa cells. First, siRNAs to Rev3 or Rev7 largely abolished UV-TLS, suggesting that these 2 gene products, which comprise Polζ, play a main role in mutagenic TLS. Second, Rev1-targeted siRNA also abrogated UV-TLS, indicating that Rev1 is also indispensable to mutagenic TLS. Third, Polη-targeted siRNA also prevented TLS to a greater extent than our expectations. Forth, although siRNA to Polι had no detectable effect, that to Polκ delayed UV-TLS. To our knowledge, this is the first study reporting apparent evidence for the participation of Polκ in UV-TLS.
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Affiliation(s)
- Jun Takezawa
- Division of Genetic Biochemistry, The National Institute of Health and Nutrition, Shinjuku-ku, Tokyo 162-8636, Japan
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Suppression of Rev3, the catalytic subunit of Pol{zeta}, sensitizes drug-resistant lung tumors to chemotherapy. Proc Natl Acad Sci U S A 2010; 107:20786-91. [PMID: 21068376 DOI: 10.1073/pnas.1011409107] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Platinum-based chemotherapeutic drugs are front-line therapies for the treatment of non-small cell lung cancer. However, intrinsic drug resistance limits the clinical efficacy of these agents. Recent evidence suggests that loss of the translesion polymerase, Polζ, can sensitize tumor cell lines to cisplatin, although the relevance of these findings to the treatment of chemoresistant tumors in vivo has remained unclear. Here, we describe a tumor transplantation approach that enables the rapid introduction of defined genetic lesions into a preclinical model of lung adenocarcinoma. Using this approach, we examined the effect of impaired translesion DNA synthesis on cisplatin response in aggressive late-stage lung cancers. In the presence of reduced levels of Rev3, an essential component of Polζ, tumors exhibited pronounced sensitivity to cisplatin, leading to a significant extension in overall survival of treated recipient mice. Additionally, treated Rev3-deficient cells exhibited reduced cisplatin-induced mutation, a process that has been implicated in the induction of secondary malignancies following chemotherapy. Taken together, our data illustrate the potential of Rev3 inhibition as an adjuvant therapy for the treatment of chemoresistant malignancies, and highlight the utility of rapid transplantation methodologies for evaluating mechanisms of chemotherapeutic resistance in preclinical settings.
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Abstract
The development of cancer drug resistance is a persistent clinical problem limiting the successful treatment of disseminated malignancies. However, the molecular mechanisms by which initially chemoresponsive tumors develop therapeutic resistance remain poorly understood. Error-prone translesional DNA synthesis (TLS) is known to underlie the mutagenic effects of numerous anticancer agents, but little is known as to whether mutation induced by this process is ultimately relevant to tumor drug resistance. Here, we use a tractable mouse model of B-cell lymphoma to interrogate the role of error-prone translesional DNA synthesis in chemotherapy-induced mutation and resistance to front-line chemotherapy. We find that suppression of Rev1, an essential TLS scaffold protein and dCMP transferase, inhibits both cisplatin- and cyclophosphamide-induced mutagenesis. Additionally, by performing repeated cycles of tumor engraftment and treatment, we show that Rev1 plays a critical role in the development of acquired cyclophosphamide resistance. Thus, chemotherapy not only selects for drug-resistant tumor population but also directly promotes the TLS-mediated acquisition of resistance-causing mutations. These data provide an example of an alteration that prevents the acquisition of drug resistance in tumors in vivo. Because TLS also represents a critical mechanism of DNA synthesis in tumor cells following chemotherapy, these data suggest that TLS inhibition may have dual anticancer effects, sensitizing tumors to therapy as well as preventing the emergence of tumor chemoresistance.
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36
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Ho TV, Schärer OD. Translesion DNA synthesis polymerases in DNA interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:552-566. [PMID: 20658647 DOI: 10.1002/em.20573] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
DNA interstrand crosslinks (ICLs) are induced by a number of bifunctional antitumor drugs such as cisplatin, mitomycin C, or the nitrogen mustards as well as endogenous agents formed by lipid peroxidation. The repair of ICLs requires the coordinated interplay of a number of genome maintenance pathways, leading to the removal of ICLs through at least two distinct mechanisms. The major pathway of ICL repair is dependent on replication, homologous recombination, and the Fanconi anemia (FA) pathway, whereas a minor, G0/G1-specific and recombination-independent pathway depends on nucleotide excision repair. A central step in both pathways in vertebrates is translesion synthesis (TLS) and mutants in the TLS polymerases Rev1 and Pol zeta are exquisitely sensitive to crosslinking agents. Here, we review the involvement of Rev1 and Pol zeta as well as additional TLS polymerases, in particular, Pol eta, Pol kappa, Pol iota, and Pol nu, in ICL repair. Biochemical studies suggest that multiple TLS polymerases have the ability to bypass ICLs and that the extent ofbypass depends upon the structure as well as the extent of endo- or exonucleolytic processing of the ICL. As has been observed for lesions that affect only one strand of DNA, TLS polymerases are recruited by ubiquitinated proliferating nuclear antigen (PCNA) to repair ICLs in the G0/G1 pathway. By contrast, this data suggest that a different mechanism involving the FA pathway is operative in coordinating TLS in the context of replication-dependent ICL repair.
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Affiliation(s)
- The Vinh Ho
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-3400, USA
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37
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Wittschieben JP, Patil V, Glushets V, Robinson LJ, Kusewitt DF, Wood RD. Loss of DNA polymerase zeta enhances spontaneous tumorigenesis. Cancer Res 2010; 70:2770-8. [PMID: 20215524 DOI: 10.1158/0008-5472.can-09-4267] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mammalian genomes encode at least 15 distinct DNA polymerases, functioning as specialists in DNA replication, DNA repair, recombination, or bypass of DNA damage. Although the DNA polymerase zeta (polzeta) catalytic subunit REV3L is important in defense against genotoxins, little is known of its biological function. This is because REV3L is essential during embryogenesis, unlike other translesion DNA polymerases. Outstanding questions include whether any adult cells are viable in the absence of polzeta and whether polzeta status influences tumorigenesis. REV3L-deficient cells have properties that could influence the development of neoplasia in opposing ways: markedly reduced damage-induced point mutagenesis and extensive chromosome instability. To answer these questions, Rev3L was conditionally deleted from tissues of adult mice using MMTV-Cre. Loss of REV3L was tolerated in epithelial tissues but not in the hematopoietic lineage. Thymic lymphomas in Tp53(-/-) Rev3L conditional mice occurred with decreased latency and higher incidence. The lymphomas were populated predominantly by Rev3L-null T cells, showing that loss of Rev3L can promote tumorigenesis. Remarkably, the tumors were frequently oligoclonal, consistent with accelerated genetic changes in the absence of Rev3L. Mammary tumors could also arise from Rev3L-deleted cells in both Tp53(+/+) and Tp53(+/-) backgrounds. Mammary tumors in Tp53(+/-) mice deleting Rev3L formed months earlier than mammary tumors in Tp53(+/-) control mice. Prominent preneoplastic changes in glandular tissue adjacent to these tumors occurred only in mice deleting Rev3L and were associated with increased tumor multiplicity. Polzeta is the only specialized DNA polymerase yet identified that inhibits spontaneous tumor development.
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Affiliation(s)
- John P Wittschieben
- Department of Pharmacology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, USA
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Ogawara D, Muroya T, Yamauchi K, Iwamoto TA, Yagi Y, Yamashita Y, Waga S, Akiyama M, Maki H. Near-full-length REV3L appears to be a scarce maternal factor in Xenopus laevis eggs that changes qualitatively in early embryonic development. DNA Repair (Amst) 2009; 9:90-5. [PMID: 19896909 DOI: 10.1016/j.dnarep.2009.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 10/07/2009] [Accepted: 10/08/2009] [Indexed: 11/17/2022]
Abstract
REV3 is the catalytic subunit of DNA polymerase zeta (pol zeta), which is responsible for the damage-induced mutagenesis that arises during error-prone translesion synthesis in eukaryotes. The related REV3L genes in human and mouse encode proteins of approximately 350kDa, twice as large as yeast REV3, but full-length REV3L has not been identified in any vertebrate cell. We report that Xenopus laevisREV3L encodes a 352-kDa protein that has high overall amino acid sequence similarity to its mammalian counterparts, and, for the first time in a vertebrate species, we have detected putative REV3L polypeptides of 300 and 340kDa in X. laevis oocytes. Only the 300-kDa form is stored in eggs, where its concentration of about 65pM is much lower than those of other replication and repair proteins including the accessory pol zeta subunit REV7. In fertilized eggs, the levels of this polypeptide did not change until neurula; the larger 340-kDa form first appeared at stages after gastrula, suggesting a pattern of regulation during development. These observations indicate the existence of REV3L as a scarce protein, of approximately the full predicted size, whose level may impose severe constraints on the assembly of pol zeta in X. laevis.
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Affiliation(s)
- Daichi Ogawara
- Division of Molecular Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, Japan
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Kaufmann WK. The human intra-S checkpoint response to UVC-induced DNA damage. Carcinogenesis 2009; 31:751-65. [PMID: 19793801 DOI: 10.1093/carcin/bgp230] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The intra-S checkpoint response to 254 nm light (UVC)-induced DNA damage appears to have dual functions to slow the rate of DNA synthesis and stabilize replication forks that become stalled at sites of UVC-induced photoproducts in DNA. These functions should provide more time for repair of damaged DNA before its replication and thereby reduce the frequencies of mutations and chromosomal aberrations in surviving cells. This review tries to summarize the history of discovery of the checkpoint, the current state of understanding of the biological features of intra-S checkpoint signaling and its mechanisms of action with a focus primarily on intra-S checkpoint responses in human cells. The differences in the intra-S checkpoint responses to UVC and ionizing radiation-induced DNA damage are emphasized. Evidence that [6-4]pyrimidine-pyrimidone photoproducts in DNA trigger the response is discussed and the relationships between cellular responses to UVC and the molecular dose of UVC-induced DNA damage are briefly summarized. The role of the intra-S checkpoint response in protecting against solar radiation carcinogenesis remains to be determined.
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Affiliation(s)
- William K Kaufmann
- Department of Pathology and Laboratory Medicine, Center for Environmental Health and Susceptibility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA.
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40
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Pavlov YI, Shcherbakova PV. DNA polymerases at the eukaryotic fork-20 years later. Mutat Res 2009; 685:45-53. [PMID: 19682465 DOI: 10.1016/j.mrfmmm.2009.08.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 08/05/2009] [Indexed: 10/20/2022]
Abstract
Function of the eukaryotic genome depends on efficient and accurate replication of anti-parallel DNA strands. Eukaryotic DNA polymerases have different properties adapted to perform a wide spectrum of DNA transactions. Here we focus on major players in the bulk replication, DNA polymerases of the B-family. We review the organization of the replication fork in eukaryotes in a historical perspective, analyze contemporary models and propose a new integrative model of the fork.
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Affiliation(s)
- Youri I Pavlov
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE 68198-6805, USA.
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41
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Guo C, Kosarek-Stancel JN, Tang TS, Friedberg EC. Y-family DNA polymerases in mammalian cells. Cell Mol Life Sci 2009; 66:2363-81. [PMID: 19367366 PMCID: PMC11115694 DOI: 10.1007/s00018-009-0024-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 03/05/2009] [Accepted: 03/23/2009] [Indexed: 11/26/2022]
Abstract
Eukaryotic genomes are replicated with high fidelity to assure the faithful transmission of genetic information from one generation to the next. The accuracy of replication relies heavily on the ability of replicative DNA polymerases to efficiently select correct nucleotides for the polymerization reaction and, using their intrinsic exonuclease activities, to excise mistakenly incorporated nucleotides. Cells also possess a variety of specialized DNA polymerases that, by a process called translesion DNA synthesis (TLS), help overcome replication blocks when unrepaired DNA lesions stall the replication machinery. This review considers the properties of the Y-family (a subset of specialized DNA polymerases) and their roles in modulating spontaneous and genotoxic-induced mutations in mammals. We also review recent insights into the molecular mechanisms that regulate PCNA monoubiquitination and DNA polymerase switching during TLS and discuss the potential of using Y-family DNA polymerases as novel targets for cancer prevention and therapy.
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Affiliation(s)
- Caixia Guo
- Laboratory of Molecular Pathology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9072, USA.
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42
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DNA polymerase zeta cooperates with polymerases kappa and iota in translesion DNA synthesis across pyrimidine photodimers in cells from XPV patients. Proc Natl Acad Sci U S A 2009; 106:11552-7. [PMID: 19564618 DOI: 10.1073/pnas.0812548106] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human cells tolerate UV-induced cyclobutane pyrimidine dimers (CPD) by translesion DNA synthesis (TLS), carried out by DNA polymerase eta, the POLH gene product. A deficiency in DNA polymerase eta due to germ-line mutations in POLH causes the hereditary disease xeroderma pigmentosum variant (XPV), which is characterized by sunlight sensitivity and extreme predisposition to sunlight-induced skin cancer. XPV cells are UV hypermutable due to the activity of mutagenic TLS across CPD, which explains the cancer predisposition of the patients. However, the identity of the backup polymerase that carries out this mutagenic TLS was unclear. Here, we show that DNA polymerase zeta cooperates with DNA polymerases kappa and iota to carry out error-prone TLS across a TT CPD. Moreover, DNA polymerases zeta and kappa, but not iota, protect XPV cells against UV cytotoxicity, independently of nucleotide excision repair. This presents an extreme example of benefit-risk balance in the activity of TLS polymerases, which provide protection against UV cytotoxicity at the cost of increased mutagenic load.
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Chen B, Simpson DA, Zhou Y, Mitra A, Mitchell DL, Cordeiro-Stone M, Kaufmann WK. Human papilloma virus type16 E6 deregulates CHK1 and sensitizes human fibroblasts to environmental carcinogens independently of its effect on p53. Cell Cycle 2009; 8:1775-87. [PMID: 19411857 DOI: 10.4161/cc.8.11.8724] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
After treatment with ultraviolet radiation (UV), human fibroblasts that express the HPV type 16 E6 oncoprotein display defects in repair of cyclobutane pyrimidine dimers, hypersensitivity to inactivation of clonogenic survival and an inability to sustain DNA replication. To determine whether these effects are specific to depletion of p53 or inactivation of its function, fibroblast lines were constructed with ectopic expression of a dominant-negative p53 allele (p53-H179Q) to inactivate function or a short-hairpin RNA (p53-RNAi) to deplete expression of p53. Only the expression of HPV16E6 sensitized fibroblasts to UV or the chemical carcinogen, benzo[a]pyrene diolepoxide I (BPDE). Carcinogen-treated cells expressing p53-H179Q or p53-RNAi were resistant to inactivation of colony formation and did not suffer replication arrest. CHK1 is a key checkpoint kinase in the response to carcinogen-induced DNA damage. Control and p53-RNAi-expressing fibroblasts displayed phosphorylation of Ser345 on CHK1 45-120 min after carcinogen treatment with a return to near baseline phosphorylation by 6 h after treatment. HPV16E6-expressing fibroblasts displayed enhanced and sustained phosphorylation of CHK1. This was associated with enhanced phosphorylation of Thr68 on CHK2 and Ser139 on H2AX, both markers of severe replication stress and DNA double strand breaks. Incubation with the phosphatase inhibitor okadaic acid produced more phosphorylation of CHK1 in UV-treated HPV16E6-expressing cells than in p53-H179Q-expressing cells suggesting that HPV16E6 may interfere with the recovery of coupled DNA replication at replication forks that are stalled at [6-4]pyrimidine-pyrimidone photoproducts and BPDE-DNA adducts. The results indicate that HPV16E6 targets a protein or proteins other than p53 to deregulate the activity of CHK1 in carcinogen-damaged cells.
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Affiliation(s)
- Bo Chen
- Department of Nutrition Health and Food Safety, School of Public Health, Fudan University, Shanghai, China
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Abstract
New experiments show that different combinations of translesion DNA polymerases act to bypass lesions in mammalian cells, depending on the type of DNA damage. Bypass of most lesions tested was dependent on REV3L (pol zeta) and at least one additional DNA polymerase. The data fit a model whereby DNA polymerases work sequentially to bypass adducts in DNA.
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Affiliation(s)
- Kei-ichi Takata
- Department of Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Richard D Wood
- Department of Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
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Two-polymerase mechanisms dictate error-free and error-prone translesion DNA synthesis in mammals. EMBO J 2009; 28:383-93. [PMID: 19153606 DOI: 10.1038/emboj.2008.281] [Citation(s) in RCA: 227] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Accepted: 12/02/2008] [Indexed: 01/02/2023] Open
Abstract
DNA replication across blocking lesions occurs by translesion DNA synthesis (TLS), involving a multitude of mutagenic DNA polymerases that operate to protect the mammalian genome. Using a quantitative TLS assay, we identified three main classes of TLS in human cells: two rapid and error-free, and the third slow and error-prone. A single gene, REV3L, encoding the catalytic subunit of DNA polymerase zeta (pol zeta), was found to have a pivotal role in TLS, being involved in TLS across all lesions examined, except for a TT cyclobutane dimer. Genetic epistasis siRNA analysis indicated that discrete two-polymerase combinations with pol zeta dictate error-prone or error-free TLS across the same lesion. These results highlight the central role of pol zeta in both error-prone and error-free TLS in mammalian cells, and show that bypass of a single lesion may involve at least three different DNA polymerases, operating in different two-polymerase combinations.
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McNally K, Neal JA, McManus TP, McCormick JJ, Maher VM. hRev7, putative subunit of hPolzeta, plays a critical role in survival, induction of mutations, and progression through S-phase, of UV((254nm))-irradiated human fibroblasts. DNA Repair (Amst) 2008; 7:597-604. [PMID: 18295554 PMCID: PMC4275125 DOI: 10.1016/j.dnarep.2007.12.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
Translesion synthesis (TLS) refers to mechanisms by which specialized DNA polymerases incorporate nucleotides opposite fork-blocking lesions and extend replication until standard replicative polymerases take over. The first eukaryotic TLS polymerase discovered, S. cerevisiae Polzeta, consists of catalytic subunit Rev3 and non-catalytic subunit Rev7. Human homologs of these two proteins have been identified. Studies by Lawrence, Maher, and colleagues comparing UV((254nm))-irradiated human fibroblast cell strains expressing high levels of hRev3 antisense to their normal parental strains demonstrated that there was no difference in cell survival, but that the frequency of UV-induced mutations in the derivative strains was 10-fold lower than that of the parental strains, indicating that hRev3 plays a critical role in such mutagenesis. To examine the role of hRev7 in TLS, we generated human fibroblasts expressing hRev7 siRNA, identified two derivative cell strains with significantly reduced levels of hRev7, and compared them to their parental strain and a vector control for cell survival, induction of mutations, and ability to traverse the cell cycle following exposure to UV radiation. Cells with reduced hRev7 were approximately 2-times more sensitive to UV-induced cytotoxicity than the controls, indicating that unlike hRev3, hRev7 plays a protective role for cells exposed to UV radiation. When these cell strains were assayed for the frequency of mutations induced by UV in their HPRT gene, cell stains with reduced hRev7 were 5-times less sensitive to UV-induced mutagenesis than control strains. In addition, when these four strains were synchronized at the G1/S border, released from the block, UV-irradiated, and allowed to traverse the cell cycle, the rate of progression through S-phase of the cell strains with reduced hRev7 was significantly slower than that of the control strains. These data strongly support the hypothesis that hRev7 is required for TLS past UV-photoproducts, and together with hRev3, comprise hPolzeta.
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Affiliation(s)
- Kristin McNally
- Carcinogenesis Laboratory, Cell and Molecular Biology Program, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302
| | - Jessica A. Neal
- Carcinogenesis Laboratory, Cell and Molecular Biology Program, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302
| | - Terrence P. McManus
- Carcinogenesis Laboratory, Cell and Molecular Biology Program, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302
| | - J. Justin McCormick
- Carcinogenesis Laboratory, Cell and Molecular Biology Program, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302
| | - Veronica M. Maher
- Carcinogenesis Laboratory, Cell and Molecular Biology Program, Department of Microbiology & Molecular Genetics, and Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1302
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Nikolaishvili-Feinberg N, Jenkins GS, Nevis KR, Staus DP, Scarlett CO, Unsal-Kaçmaz K, Kaufmann WK, Cordeiro-Stone M. Ubiquitylation of proliferating cell nuclear antigen and recruitment of human DNA polymerase eta. Biochemistry 2008; 47:4141-50. [PMID: 18321066 DOI: 10.1021/bi702329h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study investigated the requirement for ubiquitylation of PCNA at lysine 164 during polymerase eta-dependent translesion synthesis (TLS) of site-specific cis-syn cyclobutane thymine dimers (T (wedge)T). The in vitro assay recapitulated origin-dependent initiation, fork assembly, and semiconservative, bidirectional replication of double-stranded circular DNA substrates. A phosphocellulose column was used to fractionate HeLa cell extracts into two fractions; flow-through column fraction I (CFI) contained endogenous PCNA, RPA, ubiquitin-activating enzyme E1, and ubiquitin conjugase Rad6, and eluted column fraction II (CFII) included pol delta, pol eta, and RFC. CFII supplemented with purified recombinant RPA and PCNA (wild type or K164R, in which lysine was replaced with arginine) was competent for DNA replication and TLS. K164R-PCNA complemented CFII for these activities to the same extent and efficiency as wild-type PCNA. CFII mixed with CFI (endogenous PCNA, E1, Rad6) exhibited enhanced DNA replication activity, but the same TLS efficiency determined with the purified proteins. These results demonstrate that PCNA ubiquitylation at K164 of PCNA is not required in vitro for pol eta to gain access to replication complexes at forks stalled by T (wedge)T and to catalyze TLS across this dimer.
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Affiliation(s)
- Nana Nikolaishvili-Feinberg
- Department of Pathology and Laboratory Medicine, Lineberger Comprehensive Cancer Center and Center for Environmental Health and Susceptibility, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Gan GN, Wittschieben JP, Wittschieben BØ, Wood RD. DNA polymerase zeta (pol zeta) in higher eukaryotes. Cell Res 2008; 18:174-83. [PMID: 18157155 DOI: 10.1038/cr.2007.117] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Most current knowledge about DNA polymerase zeta (pol zeta) comes from studies of the enzyme in the budding yeast Saccharomyces cerevisiae, where pol zeta consists of a complex of the catalytic subunit Rev3 with Rev7, which associates with Rev1. Most spontaneous and induced mutagenesis in yeast is dependent on these gene products, and yeast pol zeta can mediate translesion DNA synthesis past some adducts in DNA templates. Study of the homologous gene products in higher eukaryotes is in a relatively early stage, but additional functions for the eukaryotic proteins are already apparent. Suppression of vertebrate REV3L function not only reduces induced point mutagenesis but also causes larger-scale genome instability by raising the frequency of spontaneous chromosome translocations. Disruption of Rev3L function is tolerated in Drosophila, Arabidopsis, and in vertebrate cell lines under some conditions, but is incompatible with mouse embryonic development. Functions for REV3L and REV7(MAD2B) in higher eukaryotes have been suggested not only in translesion DNA synthesis but also in some forms of homologous recombination, repair of interstrand DNA crosslinks, somatic hypermutation of immunoglobulin genes and cell-cycle control. This review discusses recent developments in these areas.
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Affiliation(s)
- Gregory N Gan
- Department of Pharmacology, University of Pittsburgh Medical School, Pittsburgh, PA 15213, USA
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Fachin AL, Mello SS, Sandrin-Garcia P, Junta CM, Donadi EA, Passos GAS, Sakamoto-Hojo ET. Gene expression profiles in human lymphocytes irradiated in vitro with low doses of gamma rays. Radiat Res 2008; 168:650-65. [PMID: 18088177 DOI: 10.1667/rr0487.1] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 07/26/2007] [Indexed: 11/03/2022]
Abstract
The molecular mechanisms underlying responses to low radiation doses are still unknown, especially in normal lymphocytes, despite the evidence suggesting specific changes that may characterize cellular responses. Our purpose was to analyze gene expression profiles by DNA microarrays in human lymphocytes after in vitro irradiation (10, 25 and 50 cGy) with gamma rays. A cytogenetic analysis was also carried out for different radiation doses. G 0 lymphocytes were irradiated and induced to proliferate for 48 h; then RNA samples were collected for gene expression analysis. ANOVA was applied to data obtained in four experiments with four healthy donors, followed by SAM analysis and hierarchical clustering. For 10, 25 and 50 cGy, the numbers of significantly (FDR <or= 0.05) modulated genes were 86, 130 and 142, respectively, and 25, 35 and 33 genes were exclusively modulated for each dose, respectively. We found CYP4X1, MAPK10 and ATF6 (10 cGy), DUSP16 and RAD51L1 (25 cGy), and RAD50, REV3L and DCLRE1A (50 cGy). A set of 34 significant genes was common for all doses; while SERPINB2 and C14orf104 were up-regulated, CREB3L2, DDX49, STK25 and XAB2 were down-regulated. Chromosome damage was significantly induced for doses >or=10 cGy (total aberrations) and >or=50 cGy (dicentrics/ rings). Therefore, low to moderate radiation doses induced qualitative and/or quantitative differences and similarities in transcript profiles, reflecting the type and extent of DNA lesions. The main biological processes associated with modulated genes were metabolism, stress response/DNA repair, cell growth/differentiation, and transcription regulation. The results indicate a potential risk to humans regarding the development of genetic instability and acquired diseases.
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Affiliation(s)
- Ana L Fachin
- Departamento de Genética e, Universidade de São Paulo, Ribeirao Preto, SP, Brazil
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Cirz RT, Romesberg FE. Controlling mutation: intervening in evolution as a therapeutic strategy. Crit Rev Biochem Mol Biol 2008; 42:341-54. [PMID: 17917871 DOI: 10.1080/10409230701597741] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mutation is the driving force behind many processes linked to human disease, including cancer, aging, and the evolution of drug resistance. Mutations have traditionally been considered the inevitable consequence of replicating large genomes with polymerases of finite fidelity. Observations over the past several decades, however, have led to a new perspective on the process of mutagenesis. It has become clear that, under some circumstances, mutagenesis is a regulated process that requires the induction of pro-mutagenic enzymes and that, at least in bacteria, this induction may facilitate evolution. Herein, we review what is known about induced mutagenesis in bacteria as well as evidence that it contributes to the evolution of antibiotic resistance. Finally, we discuss the possibility that components of induced mutation pathways might be targeted for inhibition as a novel therapeutic strategy to prevent the evolution of antibiotic resistance.
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Affiliation(s)
- Ryan T Cirz
- The Scripps Research Institute, La Jolla, California 92037, USA
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