1
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Zhang H. Mechanisms of mutagenesis induced by DNA lesions: multiple factors affect mutations in translesion DNA synthesis. Crit Rev Biochem Mol Biol 2020; 55:219-251. [PMID: 32448001 DOI: 10.1080/10409238.2020.1768205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Environmental mutagens lead to mutagenesis. However, the mechanisms are very complicated and not fully understood. Environmental mutagens produce various DNA lesions, including base-damaged or sugar-modified DNA lesions, as well as epigenetically modified DNA. DNA polymerases produce mutation spectra in translesion DNA synthesis (TLS) through misincorporation of incorrect nucleotides, frameshift deletions, blockage of DNA replication, imbalance of leading- and lagging-strand DNA synthesis, and genome instability. Motif or subunit in DNA polymerases further affects the mutations in TLS. Moreover, protein interactions and accessory proteins in DNA replisome also alter mutations in TLS, demonstrated by several representative DNA replisomes. Finally, in cells, multiple DNA polymerases or cellular proteins collaborate in TLS and reduce in vivo mutagenesis. Summaries and perspectives were listed. This review shows mechanisms of mutagenesis induced by DNA lesions and the effects of multiple factors on mutations in TLS in vitro and in vivo.
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Affiliation(s)
- Huidong Zhang
- Key Laboratory of Environment and Female Reproductive Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
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2
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Mammalian DNA Polymerase Kappa Activity and Specificity. Molecules 2019; 24:molecules24152805. [PMID: 31374881 PMCID: PMC6695781 DOI: 10.3390/molecules24152805] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/27/2019] [Accepted: 07/30/2019] [Indexed: 12/31/2022] Open
Abstract
DNA polymerase (pol) kappa is a Y-family translesion DNA polymerase conserved throughout all domains of life. Pol kappa is special6 ized for the ability to copy DNA containing minor groove DNA adducts, especially N2-dG adducts, as well as to extend primer termini containing DNA damage or mismatched base pairs. Pol kappa generally cannot copy DNA containing major groove modifications or UV-induced photoproducts. Pol kappa can also copy structured or non-B-form DNA, such as microsatellite DNA, common fragile sites, and DNA containing G quadruplexes. Thus, pol kappa has roles both in maintaining and compromising genomic integrity. The expression of pol kappa is altered in several different cancer types, which can lead to genome instability. In addition, many cancer-associated single-nucleotide polymorphisms have been reported in the POLK gene, some of which are associated with poor survival and altered chemotherapy response. Because of this, identifying inhibitors of pol kappa is an active area of research. This review will address these activities of pol kappa, with a focus on lesion bypass and cellular mutagenesis.
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3
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Du H, Wang P, Li L, Wang Y. Repair and translesion synthesis of O6-alkylguanine DNA lesions in human cells. J Biol Chem 2019; 294:11144-11153. [PMID: 31167778 PMCID: PMC6643039 DOI: 10.1074/jbc.ra119.009054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
O6-alkyl-2'-deoxyguanosine (O6-alkyl-dG) lesions are among the most mutagenic and prevalent alkylated DNA lesions that are associated with cancer initiation and progression. In this study, using a shuttle vector-based strand-specific PCR-competitive replication and adduct bypass assay in conjunction with tandem MS for product identification, we systematically assessed the repair and replicative bypass of a series of O6-alkyl-dG lesions, with the alkyl group being a Me, Et, nPr, iPr, nBu, iBu, or sBu, in several human cell lines. We found that the extent of replication-blocking effects of these lesions is influenced by the size of the alkyl groups situated on the O6 position of the guanine base. We also noted involvement of distinct DNA repair pathways and translesion synthesis polymerases (Pols) in ameliorating the replication blockage effects elicited by the straight- and branched-chain O6-alkyl-dG lesions. We observed that O6-methylguanine DNA methyltransferase is effective in removing the smaller alkyl groups from the O6 position of guanine, whereas repair of the branched-chain lesions relied on nucleotide excision repair. Moreover, these lesions were highly mutagenic during cellular replication and exclusively directed G→A mutations; Pol η and Pol ζ participated in error-prone bypass of the straight-chain lesions, whereas Pol κ preferentially incorporated the correct dCMP opposite the branched-chain lesions. Together, these results uncover key cellular proteins involved in repair and translesion synthesis of O6-alkyl-dG lesions and provide a better understanding of the roles of these types of lesions in the etiology of human cancer.
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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
| | - Lin Li
- 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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4
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Du H, Wang P, Li L, Amato NJ, Wang Y. Cytotoxic and Mutagenic Properties of C1' and C3'-Epimeric Lesions of 2'-Deoxyribonucleosides in Human Cells. ACS Chem Biol 2019; 14:478-485. [PMID: 30768892 DOI: 10.1021/acschembio.8b01126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Genomic integrity is constantly challenged by exposure to environmental and endogenous genotoxic agents. Reactive oxygen species (ROS) represent one of the most common types of DNA damaging agents. While ROS mainly induce single-nucleobase lesions, epimeric 2-deoxyribose lesions can also be induced upon hydrogen atom abstraction from the C1', C3', or C4' carbon and the subsequent incorrect chemical repair of the resulting carbon-centered radicals. Herein, we investigated the replicative bypass of the C1'- and C3'-epimeric lesions of the four 2'-deoxynucleosides in HEK293T human embryonic kidney epithelial cells. Our results revealed distinct bypass efficiencies and mutagenic properties of these two types of epimeric lesions. Replicative bypasses of all C1'-epimeric lesions except α-dA are mutagenic in HEK293T cells, and their mutagenic properties are further modulated by translesion synthesis (TLS) DNA polymerases. By contrast, none of the four C3'-epimeric lesions are mutagenic, and the replicative bypass of these lesions is not compromised upon depletion of polymerase η, ι, κ, or ζ. Together, our results provide important new knowledge about the cytotoxic and mutagenic properties of C1' and C3' epimeric lesions, and reveal the roles of TLS DNA polymerases in bypassing these lesions in human cells.
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Affiliation(s)
- Hua Du
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Pengcheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Lin Li
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Nicholas J. Amato
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
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5
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Jatsenko T, Sidorenko J, Saumaa S, Kivisaar M. DNA Polymerases ImuC and DinB Are Involved in DNA Alkylation Damage Tolerance in Pseudomonas aeruginosa and Pseudomonas putida. PLoS One 2017; 12:e0170719. [PMID: 28118378 PMCID: PMC5261740 DOI: 10.1371/journal.pone.0170719] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/09/2017] [Indexed: 12/12/2022] Open
Abstract
Translesion DNA synthesis (TLS), facilitated by low-fidelity polymerases, is an important DNA damage tolerance mechanism. Here, we investigated the role and biological function of TLS polymerase ImuC (former DnaE2), generally present in bacteria lacking DNA polymerase V, and TLS polymerase DinB in response to DNA alkylation damage in Pseudomonas aeruginosa and P. putida. We found that TLS DNA polymerases ImuC and DinB ensured a protective role against N- and O-methylation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in both P. aeruginosa and P. putida. DinB also appeared to be important for the survival of P. aeruginosa and rapidly growing P. putida cells in the presence of methyl methanesulfonate (MMS). The role of ImuC in protection against MMS-induced damage was uncovered under DinB-deficient conditions. Apart from this, both ImuC and DinB were critical for the survival of bacteria with impaired base excision repair (BER) functions upon alkylation damage, lacking DNA glycosylases AlkA and/or Tag. Here, the increased sensitivity of imuCdinB double deficient strains in comparison to single mutants suggested that the specificity of alkylated DNA lesion bypass of DinB and ImuC might also be different. Moreover, our results demonstrated that mutagenesis induced by MMS in pseudomonads was largely ImuC-dependent. Unexpectedly, we discovered that the growth temperature of bacteria affected the efficiency of DinB and ImuC in ensuring cell survival upon alkylation damage. Taken together, the results of our study disclosed the involvement of ImuC in DNA alkylation damage tolerance, especially at low temperatures, and its possible contribution to the adaptation of pseudomonads upon DNA alkylation damage via increased mutagenesis.
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Affiliation(s)
- Tatjana Jatsenko
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail: (MK); (TJ)
| | - Julia Sidorenko
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Signe Saumaa
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Maia Kivisaar
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail: (MK); (TJ)
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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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7
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Bostian ACL, Eoff RL. Aberrant Kynurenine Signaling Modulates DNA Replication Stress Factors and Promotes Genomic Instability in Gliomas. Chem Res Toxicol 2016; 29:1369-80. [PMID: 27482758 DOI: 10.1021/acs.chemrestox.6b00255] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Metabolism of the essential amino acid L-tryptophan (TRP) is implicated in a number of neurological conditions including depression, neurodegenerative diseases, and cancer. The TRP catabolite kynurenine (KYN) has recently emerged as an important neuroactive factor in brain tumor pathogenesis, with additional studies implicating KYN in other types of cancer. Often highlighted as a modulator of the immune response and a contributor to immune escape for malignant tumors, it is well-known that KYN has effects on the production of the coenzyme nicotinamide adenine dinucleotide (NAD(+)), which can have a direct impact on DNA repair, replication, cell division, redox signaling, and mitochondrial function. Additional effects of KYN signaling are imparted through its role as an endogenous agonist for the aryl hydrocarbon receptor (AhR), and it is largely through activation of the AhR that KYN appears to mediate malignant progression in gliomas. We have recently reported on the ability of KYN signaling to modulate expression of human DNA polymerase kappa (hpol κ), a translesion enzyme involved in bypass of bulky DNA lesions and activation of the replication stress response. Given the impact of KYN on NAD(+) production, AhR signaling, and translesion DNA synthesis, it follows that dysregulation of KYN signaling in cancer may promote malignancy through alterations in the level of endogenous DNA damage and replication stress. In this perspective, we discuss the connections between KYN signaling, DNA damage tolerance, and genomic instability, as they relate to cancer.
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Affiliation(s)
- April C L Bostian
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , 4301 W. Markham Street, Little Rock, Arkansas 72205-7199, United States
| | - Robert L Eoff
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , 4301 W. Markham Street, Little Rock, Arkansas 72205-7199, United States
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8
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Kanemaru Y, Suzuki T, Niimi N, Grúz P, Matsumoto K, Adachi N, Honma M, Nohmi T. Catalytic and non-catalytic roles of DNA polymerase κ in the protection of human cells against genotoxic stresses. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:650-62. [PMID: 26031400 DOI: 10.1002/em.21961] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 05/13/2015] [Accepted: 05/26/2015] [Indexed: 05/07/2023]
Abstract
DNA polymerase κ (Pol κ) is a specialized DNA polymerase involved in translesion DNA synthesis. Although its bypass activities across lesions are well characterized in biochemistry, its cellular protective roles against genotoxic insults are still elusive. To better understand the in vivo protective roles, we have established a human cell line deficient in the expression of Pol κ (KO) and another expressing catalytically dead Pol κ (CD), to examine the cytotoxic sensitivity to 11 genotoxins including ultraviolet C light (UV). These cell lines were established in a genetic background of Nalm-6-MSH+, a human lymphoblastic cell line that has high efficiency for gene targeting, and functional p53 and mismatch repair activities. We classified the genotoxins into four groups. Group 1 includes benzo[a]pyrene diolepoxide, mitomycin C, and bleomycin, where the sensitivity was equally higher in KO and CD than in the cell line expressing wild-type Pol κ (WT). Group 2 includes hydrogen peroxide and menadione, where hypersensitivity was observed only in KO. Group 3 includes methyl methanesulfonate and ethyl methanesulfonate, where hypersensitivity was observed only in CD. Group 4 includes UV and three chemicals, where the chemicals exhibited similar cytotoxicity to all three cell lines. The results suggest that Pol κ not only protects cells from genotoxic DNA lesions via DNA polymerase activities, but also contributes to genome integrity by acting as a non-catalytic protein against oxidative damage caused by hydrogen peroxide and menadione. The non-catalytic roles of Pol κ in protection against oxidative damage by hydrogen peroxide are discussed.
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Affiliation(s)
- Yuki Kanemaru
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
- Division of Toxicology, Department of Pharmacology Toxicology and Therapeutics, Showa University School of Pharmacy, Shinagawa-Ku, Tokyo, 142-0064, Japan
| | - Tetsuya Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Naoko Niimi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Petr Grúz
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Kyomu Matsumoto
- Toxicology Division, The Institute of Environmental Toxicology, Joso-Shi, Ibaraki, 303-0043, Japan
| | - Noritaka Adachi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa, 236-0027, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-Ku, Tokyo, 158-8501, Japan
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9
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Wit N, Buoninfante OA, van den Berk PCM, Jansen JG, Hogenbirk MA, de Wind N, Jacobs H. Roles of PCNA ubiquitination and TLS polymerases κ and η in the bypass of methyl methanesulfonate-induced DNA damage. Nucleic Acids Res 2014; 43:282-94. [PMID: 25505145 PMCID: PMC4288191 DOI: 10.1093/nar/gku1301] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Translesion synthesis (TLS) provides a highly conserved mechanism that enables DNA synthesis on a damaged template. TLS is performed by specialized DNA polymerases of which polymerase (Pol) κ is important for the cellular response to DNA damage induced by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), ultraviolet (UV) light and the alkylating agent methyl methanesulfonate (MMS). As TLS polymerases are intrinsically error-prone, tight regulation of their activity is required. One level of control is provided by ubiquitination of the homotrimeric DNA clamp PCNA at lysine residue 164 (PCNA-Ub). We here show that Polκ can function independently of PCNA modification and that Polη can function as a backup during TLS of MMS-induced lesions. Compared to cell lines deficient for PCNA modification (Pcna(K164R)) or Polκ, double mutant cell lines display hypersensitivity to MMS but not to BPDE or UV-C. Double mutant cells also displayed delayed post-replicative TLS, accumulate higher levels of replication stress and delayed S-phase progression. Furthermore, we show that Polη and Polκ are redundant in the DNA damage bypass of MMS-induced DNA damage. Taken together, we provide evidence for PCNA-Ub-independent activation of Polκ and establish Polη as an important backup polymerase in the absence of Polκ in response to MMS-induced DNA damage.
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Affiliation(s)
- Niek Wit
- Division of Biological Stress Responses, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Paul C M van den Berk
- Division of Biological Stress Responses, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jacob G Jansen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Marc A Hogenbirk
- Division of Biological Stress Responses, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Niels de Wind
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Heinz Jacobs
- Division of Biological Stress Responses, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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10
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Pillaire MJ, Bétous R, Hoffmann JS. Role of DNA polymerase κ in the maintenance of genomic stability. Mol Cell Oncol 2014; 1:e29902. [PMID: 27308312 PMCID: PMC4905163 DOI: 10.4161/mco.29902] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 12/28/2022]
Abstract
To ensure high cell viability and genomic stability, cells have evolved two major mechanisms to deal with the constant challenge of DNA replication fork arrest during S phase of the cell cycle: (1) induction of the ataxia telangiectasia and Rad3-related (ATR) replication checkpoint mechanism, and (2) activation of a pathway that bypasses DNA damage and DNA with abnormal structure and is mediated by translesion synthesis (TLS) Y-family DNA polymerases. This review focuses on how DNA polymerase kappa (Pol κ), one of the most highly conserved TLS DNA polymerases, is involved in each of these pathways and thereby coordinates them to choreograph the response to a stalled replication fork. We also describe how loss of Pol κ regulation, which occurs frequently in human cancers, affects genomic stability and contributes to cancer development.
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Affiliation(s)
- Marie-Jeanne Pillaire
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
| | - Rémy Bétous
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
| | - Jean-Sébastien Hoffmann
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
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11
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Mouse DNA polymerase kappa has a functional role in the repair of DNA strand breaks. DNA Repair (Amst) 2013; 12:377-88. [PMID: 23522793 DOI: 10.1016/j.dnarep.2013.02.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/20/2013] [Accepted: 02/26/2013] [Indexed: 01/22/2023]
Abstract
The Y-family of DNA polymerases support of translesion DNA synthesis (TLS) associated with stalled DNA replication by DNA damage. Recently, a number of studies suggest that some specialized TLS polymerases also support other aspects of DNA metabolism beyond TLS in vivo. Here we show that mouse polymerase kappa (Polκ) could accumulate at laser-induced sites of damage in vivo resembling polymerases eta and iota. The recruitment was mediated through Polκ C-terminus which contains the PCNA-interacting peptide, ubiquitin zinc finger motif 2 and nuclear localization signal. Interestingly, this recruitment was significantly reduced in MSH2-deficient LoVo cells and Rad18-depleted cells. We further observed that Polκ-deficient mouse embryo fibroblasts were abnormally sensitive to H2O2 treatment and displayed defects in both single-strand break repair and double-strand break repair. We speculate that Polκ may have an important role in strand break repair following oxidative stress in vivo.
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12
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Parsons JL, Nicolay NH, Sharma RA. Biological and therapeutic relevance of nonreplicative DNA polymerases to cancer. Antioxid Redox Signal 2013; 18:851-73. [PMID: 22794079 PMCID: PMC3557440 DOI: 10.1089/ars.2011.4203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Apart from surgical approaches, the treatment of cancer remains largely underpinned by radiotherapy and pharmacological agents that cause damage to cellular DNA, which ultimately causes cancer cell death. DNA polymerases, which are involved in the repair of cellular DNA damage, are therefore potential targets for inhibitors for improving the efficacy of cancer therapy. They can be divided, according to their main function, into two groups, namely replicative and nonreplicative enzymes. At least 15 different DNA polymerases, including their homologs, have been discovered to date, which vary considerably in processivity and fidelity. Many of the nonreplicative (specialized) DNA polymerases replicate DNA in an error-prone fashion, and they have been shown to participate in multiple DNA damage repair and tolerance pathways, which are often aberrant in cancer cells. Alterations in DNA repair pathways involving DNA polymerases have been linked with cancer survival and with treatment response to radiotherapy or to classes of cytotoxic drugs routinely used for cancer treatment, particularly cisplatin, oxaliplatin, etoposide, and bleomycin. Indeed, there are extensive preclinical data to suggest that DNA polymerase inhibition may prove to be a useful approach for increasing the effectiveness of therapies in patients with cancer. Furthermore, specialized DNA polymerases warrant examination of their potential use as clinical biomarkers to select for particular cancer therapies, to individualize treatment for patients.
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Affiliation(s)
- Jason L Parsons
- Cancer Research UK-Medical Research Council, Oncology Department, Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom
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13
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Williams HL, Gottesman ME, Gautier J. Replication-independent repair of DNA interstrand crosslinks. Mol Cell 2012; 47:140-7. [PMID: 22658724 DOI: 10.1016/j.molcel.2012.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 03/19/2012] [Accepted: 04/17/2012] [Indexed: 12/24/2022]
Abstract
DNA interstrand crosslinks (ICLs) are cytotoxic lesions that covalently link opposite strands of the DNA helix and block DNA unwinding. ICLs are repaired during and outside S phase, and replication-independent ICL repair (RIR) is critical to maintain genomic integrity and to allow transcription in nondividing or slowly dividing cells. Here, we show that the Y family DNA polymerase kappa (Pol κ) is essential for RIR of a site-specific ICL lesion in Xenopus egg extracts, and that both its catalytic activity and UBZ domains are required for this function. We also demonstrate a requirement for PCNA and its modification on lysine 164. Finally, we show that Pol κ participates in ICL repair in mammalian cells, particularly in G0. Our results identify key components of the RIR pathway and begin to unravel its mechanism.
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Affiliation(s)
- Hannah L Williams
- Institute for Cancer Genetics, Department of Genetics and Development, Columbia University, New York, NY 10032, USA
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14
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Abstract
Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.
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Affiliation(s)
- Dragony Fu
- Departments of Biological Engineering and Biology, Center for Environmental Health Sciences, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Jennifer A. Calvo
- Departments of Biological Engineering and Biology, Center for Environmental Health Sciences, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Leona D Samson
- Departments of Biological Engineering and Biology, Center for Environmental Health Sciences, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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15
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Lin JR, Zeman MK, Chen JY, Yee MC, Cimprich KA. SHPRH and HLTF act in a damage-specific manner to coordinate different forms of postreplication repair and prevent mutagenesis. Mol Cell 2011; 42:237-49. [PMID: 21396873 DOI: 10.1016/j.molcel.2011.02.026] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 10/29/2010] [Accepted: 02/23/2011] [Indexed: 12/27/2022]
Abstract
Postreplication repair (PRR) pathways play important roles in restarting stalled replication forks and regulating mutagenesis. In yeast, Rad5-mediated damage avoidance and Rad18-mediated translesion synthesis (TLS) are two forms of PRR. Two Rad5-related proteins, SHPRH and HLTF, have been identified in mammalian cells, but their specific roles in PRR are unclear. Here, we show that HLTF and SHPRH suppress mutagenesis in a damage-specific manner, preventing mutations induced by UV and MMS, respectively. Following UV, HLTF enhances PCNA monoubiquitination and recruitment of TLS polymerase η, while also inhibiting SHPRH function. In contrast, MMS promotes the degradation of HLTF and the interactions of SHPRH with Rad18 and polymerase κ. Our data suggest not only that cells differentially utilize HLTF and SHPRH for different forms of DNA damage, but also, surprisingly, that HLTF and SHPRH may coordinate the two main branches of PRR to choose the proper bypass mechanism for minimizing mutagenesis.
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Affiliation(s)
- Jia-Ren Lin
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
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16
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Hirota K, Sonoda E, Kawamoto T, Motegi A, Masutani C, Hanaoka F, Szüts D, Iwai S, Sale JE, Lehmann A, Takeda S. Simultaneous disruption of two DNA polymerases, Polη and Polζ, in Avian DT40 cells unmasks the role of Polη in cellular response to various DNA lesions. PLoS Genet 2010; 6. [PMID: 20949111 PMCID: PMC2951353 DOI: 10.1371/journal.pgen.1001151] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 09/08/2010] [Indexed: 12/18/2022] Open
Abstract
Replicative DNA polymerases are frequently stalled by DNA lesions. The resulting replication blockage is released by homologous recombination (HR) and translesion DNA synthesis (TLS). TLS employs specialized TLS polymerases to bypass DNA lesions. We provide striking in vivo evidence of the cooperation between DNA polymerase η, which is mutated in the variant form of the cancer predisposition disorder xeroderma pigmentosum (XP-V), and DNA polymerase ζ by generating POLη−/−/POLζ−/− cells from the chicken DT40 cell line. POLζ−/− cells are hypersensitive to a very wide range of DNA damaging agents, whereas XP-V cells exhibit moderate sensitivity to ultraviolet light (UV) only in the presence of caffeine treatment and exhibit no significant sensitivity to any other damaging agents. It is therefore widely believed that Polη plays a very specific role in cellular tolerance to UV-induced DNA damage. The evidence we present challenges this assumption. The phenotypic analysis of POLη−/−/POLζ−/− cells shows that, unexpectedly, the loss of Polη significantly rescued all mutant phenotypes of POLζ−/− cells and results in the restoration of the DNA damage tolerance by a backup pathway including HR. Taken together, Polη contributes to a much wide range of TLS events than had been predicted by the phenotype of XP-V cells. DNA replication is a fragile biochemical reaction, as the replicative DNA polymerases are readily stalled by DNA lesions. The resulting replication blockage is released by translesion DNA synthesis (TLS), which employs specialized TLS polymerases to bypass DNA lesions. There are at least seven TLS polymerases known in vertebrates. However, how they cooperate in vivo remains one of central questions in the field. We analyzed this functional interaction by genetically disrupting two of major TLS polymerases, Polη and Polζ, in the unique genetic model organism, chicken DT40 cells. Currently, it is widely believed that Polη plays a very specific role in cellular tolerance to ultraviolet light–induced DNA damage. Polζ, on the other hand, plays a key role in cellular tolerance to a very wide range of DNA–damaging agents, as POLζ−/− cells are hypersensitivity to a number of DNA damaging agents. Our phenotypic analysis of POLη−/−/POLζ−/− cells shows that, unexpectedly, the loss of Polη significantly rescued all mutant phenotypes of POLζ−/− cells. The genetic interaction shown here reveals a previously unappreciated role of human Polη in cellular response to a wide variety of DNA lesions and two-step collaborative action of Polymerase η and ζ.
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Affiliation(s)
- Kouji Hirota
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Eiichiro Sonoda
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takuo Kawamoto
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akira Motegi
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Chikahide Masutani
- Solution-Oriented Research for Science and Technology (SORST), Japan Science and Technology Agency, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Fumio Hanaoka
- Solution-Oriented Research for Science and Technology (SORST), Japan Science and Technology Agency, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Dávid Szüts
- St. George's, University of London, London, United Kingdom
| | - Shigenori Iwai
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Julian E. Sale
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alan Lehmann
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Shunichi Takeda
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail:
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17
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Roos WP, Tsaalbi-Shtylik A, Tsaryk R, Güvercin F, de Wind N, Kaina B. The translesion polymerase Rev3L in the tolerance of alkylating anticancer drugs. Mol Pharmacol 2009; 76:927-34. [PMID: 19641035 DOI: 10.1124/mol.109.058131] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Temozolomide and fotemustine, representing methylating and chloroethylating agents, respectively, are used in the treatment of glioma and malignant melanoma. Because chemoresistance of these tumors is a common phenomenon, identification of the underlying mechanisms is needed. Here we show that Rev3L, the catalytic subunit of the translesion DNA polymerase zeta, mediates resistance to both temozolomide and fotemustine. Rev3L knockout cells are hypersensitive to both agents. It is remarkable that cells heterozygous for Rev3L showed an intermediate sensitivity. Rev3L is not involved in the tolerance of the toxic O6-methylguanine lesion. However, a possible role of Rev3L in the tolerance of O6-chloroethylguanine or the subsequently formed N1-guanine-N3-cytosine interstrand cross-link is shown. Rev3L had no influence on base excision repair (BER) of the N-alkylation lesions but is very likely to be involved in the tolerance of N-alkylations or apurinic/apyrimidinic sites originating from them. We also show that Rev3L exerts its protective effect in replicating cells and that loss of Rev3L leads to a significant increase in DNA double-strand breaks after temozolomide and fotemustine treatment. These data show that Rev3L contributes to temozolomide and fotemustine resistance, thus acting in concert with O6-methylguanine-DNA methyltransferase, BER, mismatch repair, and double-strand break repair in defense against simple alkylating anticancer drugs.
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Affiliation(s)
- Wynand Paul Roos
- Institute of Toxicology, University Medicine Mainz, Mainz D-55131, Germany
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18
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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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19
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Waters LS, Minesinger BK, Wiltrout ME, D'Souza S, Woodruff RV, Walker GC. Eukaryotic translesion polymerases and their roles and regulation in DNA damage tolerance. Microbiol Mol Biol Rev 2009; 73:134-54. [PMID: 19258535 PMCID: PMC2650891 DOI: 10.1128/mmbr.00034-08] [Citation(s) in RCA: 440] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
DNA repair and DNA damage tolerance machineries are crucial to overcome the vast array of DNA damage that a cell encounters during its lifetime. In this review, we summarize the current state of knowledge about the eukaryotic DNA damage tolerance pathway translesion synthesis (TLS), a process in which specialized DNA polymerases replicate across from DNA lesions. TLS aids in resistance to DNA damage, presumably by restarting stalled replication forks or filling in gaps that remain in the genome due to the presence of DNA lesions. One consequence of this process is the potential risk of introducing mutations. Given the role of these translesion polymerases in mutagenesis, we discuss the significant regulatory mechanisms that control the five known eukaryotic translesion polymerases: Rev1, Pol zeta, Pol kappa, Pol eta, and Pol iota.
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Affiliation(s)
- Lauren S Waters
- Department of Biology, Massachusetts Institute of Technology, Building 68, Room 653, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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20
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Takenaka K, Miki Y. Introduction and characterization of a polymerase-dead point mutation into the POLK gene in vertebrates. FEBS Lett 2009; 583:661-4. [PMID: 19166845 DOI: 10.1016/j.febslet.2008.12.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 12/21/2008] [Accepted: 12/24/2008] [Indexed: 11/28/2022]
Abstract
The chicken DT40 cell line is widely used for gene knock-outs. We attempted to introduce a polymerase-dead point mutation into Polkappa, a polymerase for translesion DNA synthesis, taking advantage of the highly efficient targeted integration in DT40 cells. The resulting cells (REV3(-/-)POLK(/)(pol-dead)) proliferated with the same kinetics as the parental REV3(-/-) cells. Though the mock-treated REV3(-/-)POLK(/)(mock) cells showed the same sensitivity as the parental REV3(-/-) cells to methyl methanesulfonate, the REV3(-/-)POLK(/)(pol-dead) cells demonstrated the same sensitivity as the REV3(-/-)POLK(/-) double knock-out cells. This implies that the presence of the polymerase-dead Polkappa does not interfere with other polymerases repairing monoalkylation damage.
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Affiliation(s)
- Katsuya Takenaka
- Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, 113-8510 Tokyo, Japan
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21
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Plosky BS, Frank EG, Berry DA, Vennall GP, McDonald JP, Woodgate R. Eukaryotic Y-family polymerases bypass a 3-methyl-2'-deoxyadenosine analog in vitro and methyl methanesulfonate-induced DNA damage in vivo. Nucleic Acids Res 2008; 36:2152-62. [PMID: 18281311 PMCID: PMC2367705 DOI: 10.1093/nar/gkn058] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
N3-methyl-adenine (3MeA) is the major cytotoxic lesion formed in DNA by SN2 methylating agents. The lesion presumably blocks progression of cellular replicases because the N3-methyl group hinders interactions between the polymerase and the minor groove of DNA. However, this hypothesis has yet to be rigorously proven, as 3MeA is intrinsically unstable and is converted to an abasic site, which itself is a blocking lesion. To circumvent these problems, we have chemically synthesized a 3-deaza analog of 3MeA (3dMeA) as a stable phosphoramidite and have incorporated the analog into synthetic oligonucleotides that have been used in vitro as templates for DNA replication. As expected, the 3dMeA lesion blocked both human DNA polymerases α and δ. In contrast, human polymerases η, ι and κ, as well as Saccharomyces cerevisiae polη were able to bypass the lesion, albeit with varying efficiencies and accuracy. To confirm the physiological relevance of our findings, we show that in S. cerevisiae lacking Mag1-dependent 3MeA repair, polη (Rad30) contributes to the survival of cells exposed to methyl methanesulfonate (MMS) and in the absence of Mag1, Rad30 and Rev3, human polymerases η, ι and κ are capable of restoring MMS-resistance to the normally MMS-sensitive strain.
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Affiliation(s)
- Brian S Plosky
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
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22
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Akbari M, Krokan HE. Cytotoxicity and mutagenicity of endogenous DNA base lesions as potential cause of human aging. Mech Ageing Dev 2008; 129:353-65. [PMID: 18355895 DOI: 10.1016/j.mad.2008.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 01/25/2008] [Accepted: 01/28/2008] [Indexed: 11/26/2022]
Abstract
Endogenous factors constitute a substantial source of damage to the genomic DNA. The type of damage includes a number of different base lesions and single- and double-strand breaks. Unrepaired DNA damage can give rise to mutations and may cause cell death. A number of studies have demonstrated an association between aging and the accumulation of DNA damage. This may be attributed to reduced DNA repair with age, although this is apparently not a general feature for all types of damage and repair mechanisms. Therefore, detailed studies that improve our knowledge of DNA repair systems as well as mutagenic and toxic effects of DNA lesions will help us to gain a better insight into the mechanisms of aging. The aim of this review is to provide a brief description of cytotoxic and mutagenic endogenous DNA lesions that are mainly repaired by base excision repair and single-strand break repair pathways and to discuss the potential role of DNA lesions and DNA repair dysfunction in the onset of human aging.
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Affiliation(s)
- Mansour Akbari
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
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23
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Guo C, Tang TS, Bienko M, Dikic I, Friedberg EC. Requirements for the interaction of mouse Polkappa with ubiquitin and its biological significance. J Biol Chem 2007; 283:4658-64. [PMID: 18162470 DOI: 10.1074/jbc.m709275200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polkappa protein is a eukaryotic member of the DinB/Polkappa branch of the Y-family DNA polymerases, which are involved in the tolerance of DNA damage by replicative bypass. Despite universal conservation through evolution, the precise role(s) of Polkappa in this process has remained unknown. Here we report that mouse Polkappa can physically interact with ubiquitin by yeast two-hybrid screening, glutathione S-transferase pulldown, and immunoprecipitation methods. The association of Polkappa with ubiquitin requires the ubiquitin-binding motifs located at the C terminus of Polkappa. In addition, Polkappa binds with monoubiquitinated proliferating cell nuclear antigen (PCNA) more robustly than with non-ubiquitinated PCNA. The ubiquitin-binding motifs mediate the enhanced association between monoubiquitinated PCNA and Polkappa. The ubiquitin-binding motifs are also required for Polkappa to form nuclear foci after UV radiation. However, the ubiquitin-binding motifs do not affect Polkappa half-life. Finally, we have examined levels of Polkappa expression following the exposure of mouse cells to benzo[a]pyrene-dihydrodiol epoxide or UVB radiation.
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Affiliation(s)
- Caixia Guo
- Laboratory of Molecular Pathology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9072, USA
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24
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Bjedov I, Dasgupta CN, Slade D, Le Blastier S, Selva M, Matic I. Involvement of Escherichia coli DNA polymerase IV in tolerance of cytotoxic alkylating DNA lesions in vivo. Genetics 2007; 176:1431-40. [PMID: 17483416 PMCID: PMC1931539 DOI: 10.1534/genetics.107.072405] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 05/03/2007] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli PolIV, a DNA polymerase capable of catalyzing synthesis past replication-blocking DNA lesions, belongs to the most ubiquitous branch of Y-family DNA polymerases. The goal of this study is to identify spontaneous DNA damage that is bypassed specifically and accurately by PolIV in vivo. We increased the amount of spontaneous DNA lesions using mutants deficient for different DNA repair pathways and measured mutation frequency in PolIV-proficient and -deficient backgrounds. We found that PolIV performs an error-free bypass of DNA damage that accumulates in the alkA tag genetic background. This result indicates that PolIV is involved in the error-free bypass of cytotoxic alkylating DNA lesions. When the amount of cytotoxic alkylating DNA lesions is increased by the treatment with chemical alkylating agents, PolIV is required for survival in an alkA tag-proficient genetic background as well. Our study, together with the reported involvement of the mammalian PolIV homolog, Polkappa, in similar activity, indicates that Y-family DNA polymerases from the DinB branch can be added to the list of evolutionarily conserved molecular mechanisms that counteract cytotoxic effects of DNA alkylation. This activity is of major biological relevance because alkylating agents are continuously produced endogenously in all living cells and are also present in the environment.
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Affiliation(s)
- Ivana Bjedov
- INSERM U571, Faculté de Médecine, Université Paris 5, 75730 Paris Cedex 15, France
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25
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Wyatt MD, Pittman DL. Methylating agents and DNA repair responses: Methylated bases and sources of strand breaks. Chem Res Toxicol 2007; 19:1580-94. [PMID: 17173371 PMCID: PMC2542901 DOI: 10.1021/tx060164e] [Citation(s) in RCA: 314] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The chemical methylating agents methylmethane sulfonate (MMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) have been used for decades as classical DNA damaging agents. These agents have been utilized to uncover and explore pathways of DNA repair, DNA damage response, and mutagenesis. MMS and MNNG modify DNA by adding methyl groups to a number of nucleophilic sites on the DNA bases, although MNNG produces a greater percentage of O-methyl adducts. There has been substantial progress elucidating direct reversal proteins that remove methyl groups and base excision repair (BER), which removes and replaces methylated bases. Direct reversal proteins and BER, thus, counteract the toxic, mutagenic, and clastogenic effects of methylating agents. Despite recent progress, the complexity of DNA damage responses to methylating agents is still being discovered. In particular, there is growing understanding of pathways such as homologous recombination, lesion bypass, and mismatch repair that react when the response of direct reversal proteins and BER is insufficient. Furthermore, the importance of proper balance within the steps in BER has been uncovered with the knowledge that DNA structural intermediates during BER are deleterious. A number of issues complicate the elucidation of the downstream responses when direct reversal is insufficient or BER is imbalanced. These include inter-species differences, cell-type-specific differences within mammals and between cancer cell lines, and the type of methyl damage or BER intermediate encountered. MMS also carries a misleading reputation of being a radiomimetic, that is, capable of directly producing strand breaks. This review focuses on the DNA methyl damage caused by MMS and MNNG for each site of potential methylation to summarize what is known about the repair of such damage and the downstream responses and consequences if the damage is not repaired.
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Affiliation(s)
- Michael D Wyatt
- Department of Basic Pharmaceutical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208, USA.
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