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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: implications for the fidelity of transcription and CRISPR/Cas9 gene editing. Nucleic Acids Res 2024; 52:2672-2685. [PMID: 38281263 PMCID: PMC10954477 DOI: 10.1093/nar/gkae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/02/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024] Open
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G·T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R1ρ experiments, we show that dG·rU and dT·rG mismatches in two RNA:DNA hybrids transiently form tautomeric (Genol·T/U $ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}}$ G·Tenol/Uenol) and anionic (G·T-/U-) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG·rU- formed with a ten-fold higher propensity relative to dT-·rG and dG·dT- and this could be attributed to the lower pKa (ΔpKa ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G·T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G·U versus G·T, and indicate that anionic Watson-Crick-like G·U- could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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Affiliation(s)
- Or Szekely
- Department of Biology, Duke University, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University, Durham, NC 27710, USA
| | | | - Stephanie Gu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Akanksha Manghrani
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Serafima Guseva
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
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2
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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: Implications for the fidelity of transcription and CRISPR/Cas9 gene editing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554670. [PMID: 37662220 PMCID: PMC10473728 DOI: 10.1101/2023.08.24.554670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G•T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R 1ρ experiments, we show that dG•rU and dT•rG mismatches in two RNA:DNA hybrids transiently form tautomeric (G enol •T/U ⇄G•T enol /U enol ) and anionic (G•T - /U - ) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG•rU - formed with a ten-fold higher propensity relative to dT - •rG and dG•dT - and this could be attributed to the lower pK a (Δ pK a ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G•T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G•U versus G•T, and indicate that anionic Watson-Crick-like G•U - could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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3
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Abstract
DNA damage by chemicals, radiation, or oxidative stress leads to a mutational spectrum, which is complex because it is determined in part by lesion structure, the DNA sequence context of the lesion, lesion repair kinetics, and the type of cells in which the lesion is replicated. Accumulation of mutations may give rise to genetic diseases such as cancer and therefore understanding the process underlying mutagenesis is of immense importance to preserve human health. Chemical or physical agents that cause cancer often leave their mutational fingerprints, which can be used to back-calculate the molecular events that led to disease. To make a clear link between DNA lesion structure and the mutations a given lesion induces, the field of single-lesion mutagenesis was developed. In the last three decades this area of research has seen much growth in several directions, which we attempt to describe in this Perspective.
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Affiliation(s)
- Ashis K Basu
- Department of Chemistry, The University of Connecticut Storrs, Storrs, Connecticut 06269, United States
| | - John M Essigmann
- Departments of Chemistry, Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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4
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Vaisman A, McDonald JP, Smith MR, Aspelund SL, Evans TC, Woodgate R. Identification and Characterization of Thermostable Y-Family DNA Polymerases η, ι, κ and Rev1 From a Lower Eukaryote, Thermomyces lanuginosus. Front Mol Biosci 2021; 8:778400. [PMID: 34805283 PMCID: PMC8595933 DOI: 10.3389/fmolb.2021.778400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
Y-family DNA polymerases (pols) consist of six phylogenetically separate subfamilies; two UmuC (polV) branches, DinB (pol IV, Dpo4, polκ), Rad30A/POLH (polη), and Rad30B/POLI (polι) and Rev1. Of these subfamilies, DinB orthologs are found in all three domains of life; eubacteria, archaea, and eukarya. UmuC orthologs are identified only in bacteria, whilst Rev1 and Rad30A/B orthologs are only detected in eukaryotes. Within eukaryotes, a wide array of evolutionary diversity exists. Humans possess all four Y-family pols (pols η, ι, κ, and Rev1), Schizosaccharomyces pombe has three Y-family pols (pols η, κ, and Rev1), and Saccharomyces cerevisiae only has polη and Rev1. Here, we report the cloning, expression, and biochemical characterization of the four Y-family pols from the lower eukaryotic thermophilic fungi, Thermomyces lanuginosus. Apart from the expected increased thermostability of the T. lanuginosus Y-family pols, their major biochemical properties are very similar to properties of their human counterparts. In particular, both Rad30B homologs (T. lanuginosus and human polɩ) exhibit remarkably low fidelity during DNA synthesis that is template sequence dependent. It was previously hypothesized that higher organisms had acquired this property during eukaryotic evolution, but these observations imply that polι originated earlier than previously known, suggesting a critical cellular function in both lower and higher eukaryotes.
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Affiliation(s)
- Alexandra Vaisman
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - John P McDonald
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Mallory R Smith
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Sender L Aspelund
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Thomas C Evans
- New England Biolabs Incorporated, Ipswich, MA, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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5
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Powell BV, Bacurio JHT, Basu AK. Translesion synthesis of 6-nitrochrysene-derived 2'-deoxyadenosine adduct in human cells. DNA Repair (Amst) 2020; 95:102935. [PMID: 32721818 DOI: 10.1016/j.dnarep.2020.102935] [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: 06/09/2020] [Revised: 07/10/2020] [Accepted: 07/12/2020] [Indexed: 10/23/2022]
Abstract
6-Nitrochrysene (6-NC) is a potent mutagen in bacteria and carcinogenic in animals. It is the most potent carcinogen ever tested in newborn mouse assay. DNA lesions resulting from 6-NC modification are likely to induce mutations if they are not removed by cellular defense pathways prior to DNA replication. Earlier studies showed that 6-NC-derived C8-2'-deoxyadenosine adduct, N-(dA-8-yl)-6-AC, is very slowly repaired in human cells. In this study, we have investigated replication of N-(dA-8-yl)-6-AC in human embryonic kidney (HEK 293T) cells and the roles of translesion synthesis (TLS) DNA polymerases in bypassing it. Replication of a plasmid containing a single site-specific N-(dA-8-yl)-6-AC adduct in HEK 293 T cells showed that human DNA polymerase (hPol) η and hPol κ played important roles in bypassing the adduct, since TLS efficiency was reduced to 26 % in the absence of these two polymerases compared to 83 % in polymerase-competent HEK 293T cells. The progeny from HEK 293T cells provided 12.7 % mutants predominantly containing A→T transversions. Mutation frequency (MF) was increased to 17.8 % in hPol η-deficient cells, whereas it was decreased to 3.3 % and 3.9 % when the adduct containing plasmid was replicated in hPol κ- and hPol ζ-deficient cells, respectively. The greatest reduction in MF by more than 90 % (to MF 1.2 %) was observed in hPol ζ-knockout cells in which hPol κ was knocked down. Taken together, these results suggest that hPol κ and hPol ζ are involved in the error-prone TLS of N-(dA-8-yl)-6-AC, while hPol η performs error-free bypass.
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Affiliation(s)
- Brent V Powell
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States
| | - Jan Henric T Bacurio
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States
| | - Ashis K Basu
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, United States.
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Pande P, Rebello KR, Chatterjee A, Naldiga S, Basu AK. Site-Specific Incorporation of N-(2'-Deoxyguanosine-8-yl)-6-aminochrysene Adduct in DNA and Its Replication in Human Cells. Chem Res Toxicol 2020; 33:1997-2005. [PMID: 32551527 DOI: 10.1021/acs.chemrestox.0c00197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The environmental pollutant 6-nitrochrysene (6-NC) is a potent mutagen and a mammary carcinogen in rats. 6-NC is the most potent carcinogen ever tested in the newborn mouse assay. In mammalian cells, it is metabolically activated by nitroreduction and a combination of ring oxidation and nitroreduction pathways. The nitroreduction pathway yields two major adducts with 2'-deoxyguanosine (dG), one at the C8-position, N-(dG-8-yl)-6-AC, and the other at the exocyclic N2-position, 5-(dG-N2-yl)-6-AC. Here, we report the total synthesis of a site-specific oligonucleotide containing the 6-NC-derived C8 dG adduct, N-(dG-8-yl)-6-AC. Pd-catalyzed Buchwald-Hartwig cross coupling of 6-aminochrysene with protected C8-bromo-dG derivative served as the key reaction to furnish protected N-(dG-8-yl)-6-AC in 56% yield. The monomer for solid-phase DNA synthesis was prepared by its deprotection followed by conversion to the corresponding 5'-O-dimethoxytrityl 3'-phosphoramidite, which was used to synthesize a site-specifically adducted oligonucleotide. After purification and characterization, the adduct-containing oligonucleotide was incorporated into a plasmid and replicated in human embryonic kidney (HEK) 293T cells, which showed that N-(dG-8-yl)-6-AC stalls DNA replication as evidenced by 77% translesion synthesis (TLS) efficiency relative to the control and that the adduct is mutagenic (mutation frequency (MF) 17.8%) inducing largely G→T transversions. We also investigated the roles of several translesion synthesis DNA polymerases in the bypass of N-(dG-8-yl)-6-AC using siRNA knockdown approach. TLS efficiency was reduced in hPol η-, hPol κ-, hPol ζ-, and hREV1-deficient HEK 293T cells to 66%, 45%, 37%, and 32%, respectively. Notably, TLS efficiency was reduced to 18% in cells with concurrent knockdown of hPol κ, hPol ζ, and REV1, suggesting that these three polymerases play critical roles in bypassing N-(dG-8-yl)-6-AC. MF increased to 23.1% and 32.2% in hPol κ- and hREV1-deficient cells, whereas it decreased to 11.8% in hPol ζ-deficient cells. This suggests that hPol κ and hREV1 are involved in error-free TLS of this lesion, whereas hPol ζ performs error-prone bypass.
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Affiliation(s)
- Paritosh Pande
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Kimberly R Rebello
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Arindom Chatterjee
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Spandana Naldiga
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Ashis K Basu
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
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Rodriguez-Alvarez M, Kim D, Khobta A. EGFP Reporters for Direct and Sensitive Detection of Mutagenic Bypass of DNA Lesions. Biomolecules 2020; 10:biom10060902. [PMID: 32545792 PMCID: PMC7357151 DOI: 10.3390/biom10060902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
The sustainment of replication and transcription of damaged DNA is essential for cell survival under genotoxic stress; however, the damage tolerance of these key cellular functions comes at the expense of fidelity. Thus, translesion DNA synthesis (TLS) over damaged nucleotides is a major source of point mutations found in cancers; whereas erroneous bypass of damage by RNA polymerases may contribute to cancer and other diseases by driving accumulation of proteins with aberrant structure and function in a process termed “transcriptional mutagenesis” (TM). Here, we aimed at the generation of reporters suited for direct detection of miscoding capacities of defined types of DNA modifications during translesion DNA or RNA synthesis in human cells. We performed a systematic phenotypic screen of 25 non-synonymous base substitutions in a DNA sequence encoding a functionally important region of the enhanced green fluorescent protein (EGFP). This led to the identification of four loss-of-fluorescence mutants, in which any ulterior base substitution at the nucleotide affected by the primary mutation leads to the reversal to a functional EGFP. Finally, we incorporated highly mutagenic abasic DNA lesions at the positions of primary mutations and demonstrated a high sensitivity of detection of the mutagenic DNA TLS and TM in this system.
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Affiliation(s)
- Marta Rodriguez-Alvarez
- Unit “Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany;
| | - Daria Kim
- Novosibirsk State University, 1 Pirogova St., 630090 Novosibirsk, Russia;
- Laboratory of Genome and Protein Engineering, SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Andriy Khobta
- Unit “Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, 55131 Mainz, Germany;
- Correspondence:
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8
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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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9
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Zhang C, Wang B, Zhao X, Li X, Lou Z, Chen X, Zhang F. Iron deficiency accelerates intervertebral disc degeneration through affecting the stability of DNA polymerase epsilon complex. Am J Transl Res 2018; 10:3430-3442. [PMID: 30662597 PMCID: PMC6291718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/05/2018] [Indexed: 06/09/2023]
Abstract
Iron serves as an important cofactor of iron-containing proteins that play critical roles in the maintenance of DNA stability and cell cycle progression. The disturbed iron homeostasis results in the pathogenesis of many diseases such as cancer and anemia. In this study, we found a clear correlation between iron deficiency and intervertebral disc degeneration (IDD). Through microarray experiments, we found that a large number of genes were differentially expressed in tissues with different degrees of degeneration. Among them, an iron-containing gene, PolE, the catalytic subunit of DNA polymerase epsilon (Polε), and the other two Polε subunits, including PolE2 and PolE3, were markedly downregulated, while some proteins involved in apoptosis such as Caspase-3 and -8 were significantly upregulated. By supplementation with an iron chelator deferoxamine (DFO) or knocking down either iron divalentmetal transporter 1 (DMT1) or transferrin receptor 1 (TfR1) in the nucleus pulposus (NP) cells, we found that the protein levels of PolE complex members were dramatically reduced, whereas the intrinsic apoptotic pathway was activated. Interestingly, overexpression of PolE in NP cells knocked down with either DMT1 or TfR could not reverse the stability of PolE complex and apoptosis status. In summary, our study suggests that iron deficiency is an important factor in the aggravation of IDD. Proper iron supplementation may be an effective strategy to alleviate the symptoms of patients with IDD.
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Affiliation(s)
- Chunqiang Zhang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
| | - Bing Wang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
| | - Xueling Zhao
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
| | - Xingguo Li
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
| | - Zhenkai Lou
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
| | - Xun Chen
- Department of Orthopedics, Hong-Hui Hospital, Xi’an Jiaotong UniversityXi’an 710054, Shaanxi, China
| | - Fan Zhang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical UniversityKunming 650032, Yunnan, China
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Antczak NM, Packer MR, Lu X, Zhang K, Beuning PJ. Human Y-Family DNA Polymerase κ Is More Tolerant to Changes in Its Active Site Loop than Its Ortholog Escherichia coli DinB. Chem Res Toxicol 2017; 30:2002-2012. [PMID: 28823149 DOI: 10.1021/acs.chemrestox.7b00175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA damage is a constant threat and can be bypassed in a process called translesion synthesis, which is typically carried out by Y-family DNA polymerases. Y-family DNA polymerases are conserved in all domains of life and tend to have specificity for certain types of DNA damage. Escherichia coli DinB and its human ortholog pol κ can bypass specific minor groove deoxyguanine adducts efficiently and are inhibited by major groove adducts, as Y-family DNA polymerases make contacts with the minor groove side of the DNA substrate and lack contacts with the major groove at the nascent base pair. DinB is inhibited by major groove adducts more than pol κ, and they each have active site loops of different lengths, with four additional amino acids in the DinB loop. We previously showed that the R35A active site loop mutation in DinB allows for bypass of the major groove adduct N6-furfuryl-dA. These observations led us to investigate the different active site loops by creating loop swap chimeras of DinB with a pol κ loop and vice versa by changing the loop residues in a stepwise fashion. We then determined their activity with undamaged DNA or DNA containing N2-furfuryl-dG or N6-furfuryl-dA. The DinB proteins with the pol kappa loop have low activity on all templates but have decreased misincorporation compared to either wild-type protein. The kappa proteins with the DinB loop retain activity on all templates and have decreased misincorporation compared to either wild-type protein. We assessed the thermal stability of the proteins and observed an increase in stability in the presence of all DNA templates and additional increases generally only in the presence of the undamaged and N2-furfuryl-dG adduct and dCTP, which correlates with activity. Overall we find that pol κ is more tolerant to changes in the active site loop than DinB.
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Affiliation(s)
- Nicole M Antczak
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Morgan R Packer
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Xueguang Lu
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Ke Zhang
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Penny J Beuning
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
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Yagi T, Fujikawa Y, Sawai T, Takamura-Enya T, Ito-Harashima S, Kawanishi M. Error-Prone and Error-Free Translesion DNA Synthesis over Site-Specifically Created DNA Adducts of Aryl Hydrocarbons (3-Nitrobenzanthrone and 4-Aminobiphenyl). Toxicol Res 2015; 33:265-272. [PMID: 29071010 PMCID: PMC5654197 DOI: 10.5487/tr.2017.33.4.265] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 01/05/2023] Open
Abstract
Aryl hydrocarbons such as 3-nitrobenzanthrone (NBA), 4-aminobiphenyl (ABP), acetylaminofluorene (AAF), benzo(a)pyrene (BaP), and 1-nitropyrene (NP) form bulky DNA adducts when absorbed by mammalian cells. These chemicals are metabolically activated to reactive forms in mammalian cells and preferentially get attached covalently to the N2 or C8 positions of guanine or the N6 position of adenine. The proportion of N2 and C8 guanine adducts in DNA differs among chemicals. Although these adducts block DNA replication, cells have a mechanism allowing to continue replication by bypassing these adducts: translesion DNA synthesis (TLS). TLS is performed by translesion DNA polymerases—Pol η, κ, ι, and ζ and Rev1—in an error-free or error-prone manner. Regarding the NBA adducts, namely, 2-(2′-deoxyguanosin-N2-yl)-3-aminobenzanthrone (dG-N2-ABA) and N-(2′-deoxyguanosin-8-yl)-3-aminobenzanthrone (dG-C8-ABA), dG-N2-ABA is produced more often than dG-C8-ABA, whereas dG-C8-ABA blocks DNA replication more strongly than dG-N2-ABA. dG-N2-ABA allows for a less error-prone bypass than dG-C8-ABA does. Pol η and κ are stronger contributors to TLS over dG-C8-ABA, and Pol κ bypasses dG-C8-ABA in an error-prone manner. TLS efficiency and error-proneness are affected by the sequences surrounding the adduct, as demonstrated in our previous study on an ABP adduct, N-(2′-deoxyguanosine-8-yl)-4-aminobiphenyl (dG-C8-ABP). Elucidation of the general mechanisms determining efficiency, error-proneness, and the polymerases involved in TLS over various adducts is the next step in the research on TLS. These TLS studies will clarify the mechanisms underlying aryl hydrocarbon mutagenesis and carcinogenesis in more detail.
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Affiliation(s)
- Takashi Yagi
- Department of Biology, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Yoshihiro Fujikawa
- Department of Biology, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Tomoko Sawai
- Department of Biology, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Takeji Takamura-Enya
- Department of Applied Chemistry, Kanagawa Institute of Technology, Atsugi, Kanagawa, Japan
| | - Sayoko Ito-Harashima
- Department of Biology, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Masanobu Kawanishi
- Department of Biology, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan
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