51
|
Quantitative measurement of transcriptional inhibition and mutagenesis induced by site-specifically incorporated DNA lesions in vitro and in vivo. Nat Protoc 2015; 10:1389-406. [PMID: 26292071 DOI: 10.1038/nprot.2015.094] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Aberrant transcription induced by DNA damage may confer risk for the development of cancer and other human diseases. Traditional methods for measuring lesion-induced transcriptional alterations often involve extensive colony screening and DNA sequencing procedures. Here we describe a protocol for the quantitative assessment of the effects of DNA lesions on the efficiency and fidelity of transcription in vitro and in mammalian cells. The method is also amenable to investigating the influence of specific DNA repair proteins on the biological response toward DNA damage during transcription by manipulating their gene expression. Specifically, we present detailed, step-by-step procedures, including DNA template preparation, in vitro and in vivo transcription, RNA purification, reverse-transcription PCR (RT-PCR) and restriction digestion of RT-PCR products. Analyses of restriction fragments of interest are performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and polyacrylamide gel electrophoresis (PAGE). The entire procedure described in this protocol can be completed in 15-20 d.
Collapse
|
52
|
Amato NJ, Zhai Q, Navarro DC, Niedernhofer LJ, Wang Y. In vivo detection and replication studies of α-anomeric lesions of 2'-deoxyribonucleosides. Nucleic Acids Res 2015. [PMID: 26202973 PMCID: PMC4787794 DOI: 10.1093/nar/gkv725] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
DNA damage, arising from endogenous metabolism or exposure to environmental agents, may perturb the transmission of genetic information by blocking DNA replication and/or inducing mutations, which contribute to the development of cancer and likely other human diseases. Hydroxyl radical attack on the C1′, C3′ and C4′ of 2-deoxyribose can give rise to epimeric 2-deoxyribose lesions, for which the in vivo occurrence and biological consequences remain largely unexplored. Through independent chemical syntheses of all three epimeric lesions of 2′-deoxyguanosine (dG) and liquid chromatography-tandem mass spectrometry analysis, we demonstrated unambiguously the presence of substantial levels of the α-anomer of dG (α-dG) in calf thymus DNA and in DNA isolated from mouse pancreatic tissues. We further assessed quantitatively the impact of all four α-dN lesions on DNA replication in Escherichia coli by employing a shuttle-vector method. We found that, without SOS induction, all α-dN lesions except α-dA strongly blocked DNA replication and, while replication across α-dA was error-free, replicative bypass of α-dC and α-dG yielded mainly C→A and G→A mutations. In addition, SOS induction could lead to markedly elevated bypass efficiencies for the four α-dN lesions, abolished the G→A mutation for α-dG, pronouncedly reduced the C→A mutation for α-dC and triggered T→A mutation for α-dT. The preferential misincorporation of dTMP opposite the α-dNs could be attributed to the unique base-pairing properties of the nucleobases elicited by the inversion of the configuration of the N-glycosidic linkage. Our results also revealed that Pol V played a major role in bypassing α-dC, α-dG and α-dT in vivo. The abundance of α-dG in mammalian tissue and the impact of the α-dNs on DNA replication demonstrate for the first time the biological significance of this family of DNA lesions.
Collapse
Affiliation(s)
- Nicholas J Amato
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Qianqian Zhai
- Department of Chemistry, University of California, Riverside, CA 92521, USA Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Diana C Navarro
- Department of Metabolism and Aging, The Scripps Research Institute Florida, FL 33458, USA
| | - Laura J Niedernhofer
- Department of Metabolism and Aging, The Scripps Research Institute Florida, FL 33458, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| |
Collapse
|
53
|
Nair DT, Kottur J, Sharma R. A rescue act: Translesion DNA synthesis past N(2) -deoxyguanosine adducts. IUBMB Life 2015; 67:564-74. [PMID: 26173005 DOI: 10.1002/iub.1403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 01/14/2023]
Abstract
Genomic DNA is continually subjected to a number of chemical insults that result in the formation of modified nucleotides--termed as DNA lesions. The N(2) -atom of deoxyguanosine is particularly reactive and a number of chemicals react at this site to form different kinds of DNA adducts. The N(2) -deoxyguanosine adducts perturb different genomic processes and are particularly deleterious for DNA replication as they have a strong tendency to inhibit replicative DNA polymerases. Many organisms possess specialized dPols--generally classified in the Y-family--that serves to rescue replication stalled at N(2) -dG and other adducts. A review of minor groove N(2) -adducts and the known strategies utilized by Y-family dPols to replicate past these lesions will be presented here.
Collapse
Affiliation(s)
- Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India
| | - Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India.,Manipal University, Manipal.Edu, Manipal, 576104, Karnataka, India
| | - Rahul Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India.,Manipal University, Manipal.Edu, Manipal, 576104, Karnataka, India
| |
Collapse
|
54
|
Chang SC, Fedeles BI, Wu J, Delaney JC, Li D, Zhao L, Christov PP, Yau E, Singh V, Jost M, Drennan CL, Marnett LJ, Rizzo CJ, Levine SS, Guengerich FP, Essigmann JM. Next-generation sequencing reveals the biological significance of the N(2),3-ethenoguanine lesion in vivo. Nucleic Acids Res 2015; 43:5489-500. [PMID: 25837992 PMCID: PMC4477646 DOI: 10.1093/nar/gkv243] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 12/20/2022] Open
Abstract
Etheno DNA adducts are a prevalent type of DNA damage caused by vinyl chloride (VC) exposure and oxidative stress. Etheno adducts are mutagenic and may contribute to the initiation of several pathologies; thus, elucidating the pathways by which they induce cellular transformation is critical. Although N(2),3-ethenoguanine (N(2),3-εG) is the most abundant etheno adduct, its biological consequences have not been well characterized in cells due to its labile glycosidic bond. Here, a stabilized 2'-fluoro-2'-deoxyribose analog of N(2),3-εG was used to quantify directly its genotoxicity and mutagenicity. A multiplex method involving next-generation sequencing enabled a large-scale in vivo analysis, in which both N(2),3-εG and its isomer 1,N(2)-ethenoguanine (1,N(2)-εG) were evaluated in various repair and replication backgrounds. We found that N(2),3-εG potently induces G to A transitions, the same mutation previously observed in VC-associated tumors. By contrast, 1,N(2)-εG induces various substitutions and frameshifts. We also found that N(2),3-εG is the only etheno lesion that cannot be repaired by AlkB, which partially explains its persistence. Both εG lesions are strong replication blocks and DinB, a translesion polymerase, facilitates the mutagenic bypass of both lesions. Collectively, our results indicate that N(2),3-εG is a biologically important lesion and may have a functional role in VC-induced or inflammation-driven carcinogenesis.
Collapse
Affiliation(s)
- Shiou-chi Chang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Bogdan I Fedeles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Jie Wu
- BioMicro Center, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - James C Delaney
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Deyu Li
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Linlin Zhao
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232, United States
| | - Plamen P Christov
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232, United States Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Emily Yau
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Vipender Singh
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Marco Jost
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Catherine L Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Lawrence J Marnett
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232, United States Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, United States
| | - Carmelo J Rizzo
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232, United States Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, United States
| | - Stuart S Levine
- BioMicro Center, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232, United States Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, United States
| | - John M Essigmann
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| |
Collapse
|
55
|
Interactions and Localization of Escherichia coli Error-Prone DNA Polymerase IV after DNA Damage. J Bacteriol 2015; 197:2792-809. [PMID: 26100038 DOI: 10.1128/jb.00101-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/11/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Escherichia coli's DNA polymerase IV (Pol IV/DinB), a member of the Y family of error-prone polymerases, is induced during the SOS response to DNA damage and is responsible for translesion bypass and adaptive (stress-induced) mutation. In this study, the localization of Pol IV after DNA damage was followed using fluorescent fusions. After exposure of E. coli to DNA-damaging agents, fluorescently tagged Pol IV localized to the nucleoid as foci. Stepwise photobleaching indicated ∼60% of the foci consisted of three Pol IV molecules, while ∼40% consisted of six Pol IV molecules. Fluorescently tagged Rep, a replication accessory DNA helicase, was recruited to the Pol IV foci after DNA damage, suggesting that the in vitro interaction between Rep and Pol IV reported previously also occurs in vivo. Fluorescently tagged RecA also formed foci after DNA damage, and Pol IV localized to them. To investigate if Pol IV localizes to double-strand breaks (DSBs), an I-SceI endonuclease-mediated DSB was introduced close to a fluorescently labeled LacO array on the chromosome. After DSB induction, Pol IV localized to the DSB site in ∼70% of SOS-induced cells. RecA also formed foci at the DSB sites, and Pol IV localized to the RecA foci. These results suggest that Pol IV interacts with RecA in vivo and is recruited to sites of DSBs to aid in the restoration of DNA replication. IMPORTANCE DNA polymerase IV (Pol IV/DinB) is an error-prone DNA polymerase capable of bypassing DNA lesions and aiding in the restart of stalled replication forks. In this work, we demonstrate in vivo localization of fluorescently tagged Pol IV to the nucleoid after DNA damage and to DNA double-strand breaks. We show colocalization of Pol IV with two proteins: Rep DNA helicase, which participates in replication, and RecA, which catalyzes recombinational repair of stalled replication forks. Time course experiments suggest that Pol IV recruits Rep and that RecA recruits Pol IV. These findings provide in vivo evidence that Pol IV aids in maintaining genomic stability not only by bypassing DNA lesions but also by participating in the restoration of stalled replication forks.
Collapse
|
56
|
Nevin P, Lu X, Zhang K, Engen JR, Beuning PJ. Noncognate DNA damage prevents the formation of the active conformation of the Y-family DNA polymerases DinB and DNA polymerase κ. FEBS J 2015; 282:2646-60. [PMID: 25899385 DOI: 10.1111/febs.13304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 01/24/2023]
Abstract
Y-family DNA polymerases are specialized to copy damaged DNA, and are associated with increased mutagenesis, owing to their low fidelity. It is believed that the mechanism of nucleotide selection by Y-family DNA polymerases involves conformational changes preceding nucleotidyl transfer, but there is limited experimental evidence for such structural changes. In particular, nucleotide-induced conformational changes in bacterial or eukaryotic Y-family DNA polymerases have, to date, not been extensively characterized. Using hydrogen-deuterium exchange mass spectrometry, we demonstrate here that the Escherichia coli Y-family DNA polymerase DinB and its human ortholog DNA polymerase κ undergo a conserved nucleotide-induced conformational change in the presence of undamaged DNA and the correct incoming nucleotide. Notably, this holds true for damaged DNA containing N(2) -furfuryl-deoxyguanosine, which is efficiently copied by these two polymerases, but not for damaged DNA containing the major groove modification O(6) -methyl-deoxyguanosine, which is a poor substrate. Our observations suggest that DinB and DNA polymerase κ utilize a common mechanism for nucleotide selection involving a conserved prechemical conformational transition promoted by the correct nucleotide and only preferred DNA substrates.
Collapse
Affiliation(s)
- Philip Nevin
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Xueguang Lu
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Ke Zhang
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Penny J Beuning
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| |
Collapse
|
57
|
Catalano MJ, Liu S, Andersen N, Yang Z, Johnson KM, Price NE, Wang Y, Gates KS. Chemical structure and properties of interstrand cross-links formed by reaction of guanine residues with abasic sites in duplex DNA. J Am Chem Soc 2015; 137:3933-45. [PMID: 25710271 DOI: 10.1021/jacs.5b00669] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A new type of interstrand cross-link resulting from the reaction of a DNA abasic site with a guanine residue on the opposing strand of the double helix was recently identified, but the chemical connectivity of the cross-link was not rigorously established. The work described here was designed to characterize the chemical structure and properties of dG-AP cross-links generated in duplex DNA. The approach involved characterization of the nucleoside cross-link "remnant" released by enzymatic digestion of DNA duplexes containing the dG-AP cross-link. We first carried out a chemical synthesis and complete spectroscopic structure determination of the putative cross-link remnant 9b composed of a 2-deoxyribose adduct attached to the exocyclic N(2)-amino group of dG. A reduced analogue of the cross-link remnant was also prepared (11b). Liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis revealed that the retention times and mass spectral properties of synthetic standards 9b and 11b matched those of the authentic cross-link remnants released by enzymatic digestion of duplexes containing the native and reduced dG-AP cross-link, respectively. These results establish the chemical connectivity of the dG-AP cross-link released from duplex DNA and provide a foundation for detection of this lesion in biological samples. The dG-AP cross-link in duplex DNA was remarkably stable, decomposing with a half-life of 22 days at pH 7 and 23 °C. The intrinsic chemical stability of the dG-AP cross-link suggests that this lesion in duplex DNA may have the power to block DNA-processing enzymes involved in transcription and replication.
Collapse
Affiliation(s)
| | - Shuo Liu
- ‡Environmental Toxicology Graduate Program and Department of Chemistry, University of California-Riverside, Riverside, California 92521-0403, United States
| | - Nisana Andersen
- ‡Environmental Toxicology Graduate Program and Department of Chemistry, University of California-Riverside, Riverside, California 92521-0403, United States
| | | | | | | | - Yinsheng Wang
- ‡Environmental Toxicology Graduate Program and Department of Chemistry, University of California-Riverside, Riverside, California 92521-0403, United States
| | | |
Collapse
|
58
|
Kottur J, Sharma A, Gore KR, Narayanan N, Samanta B, Pradeepkumar PI, Nair DT. Unique structural features in DNA polymerase IV enable efficient bypass of the N2 adduct induced by the nitrofurazone antibiotic. Structure 2014; 23:56-67. [PMID: 25497730 DOI: 10.1016/j.str.2014.10.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
The reduction in the efficacy of therapeutic antibiotics represents a global problem of increasing intensity and concern. Nitrofuran antibiotics act primarily through the formation of covalent adducts at the N(2) atom of the deoxyguanosine nucleotide in genomic DNA. These adducts inhibit replicative DNA polymerases (dPols), leading to the death of the prokaryote. N(2)-furfuryl-deoxyguanosine (fdG) represents a stable structural analog of the nitrofuran-induced adducts. Unlike other known dPols, DNA polymerase IV (PolIV) from E. coli can bypass the fdG adduct accurately with high catalytic efficiency. This property of PolIV is central to its role in reducing the sensitivity of E. coli toward nitrofuran antibiotics such as nitrofurazone (NFZ). We present the mechanism used by PolIV to bypass NFZ-induced adducts and thus improve viability of E. coli in the presence of NFZ. Our results can be used to develop specific inhibitors of PolIV that may potentiate the activity of nitrofuran antibiotics.
Collapse
Affiliation(s)
- Jithesh Kottur
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India; Manipal University, Manipal.edu, Madhav Nagar, Manipal 576104, India
| | - Amit Sharma
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Kiran R Gore
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Naveen Narayanan
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India; Manipal University, Manipal.edu, Madhav Nagar, Manipal 576104, India
| | - Biswajit Samanta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - Deepak T Nair
- Regional Centre for Biotechnology, 180, Udyog Vihar, Phase 1, Gurgaon 122016, India; National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India.
| |
Collapse
|
59
|
Sholder G, Loechler EL. A method to accurately quantitate intensities of (32)P-DNA bands when multiple bands appear in a single lane of a gel is used to study dNTP insertion opposite a benzo[a]pyrene-dG adduct by Sulfolobus DNA polymerases Dpo4 and Dbh. DNA Repair (Amst) 2014; 25:97-103. [PMID: 25497330 DOI: 10.1016/j.dnarep.2014.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/29/2014] [Accepted: 10/01/2014] [Indexed: 11/27/2022]
Abstract
Quantitating relative (32)P-band intensity in gels is desired, e.g., to study primer-extension kinetics of DNA polymerases (DNAPs). Following imaging, multiple (32)P-bands are often present in lanes. Though individual bands appear by eye to be simple and well-resolved, scanning reveals they are actually skewed-Gaussian in shape and neighboring bands are overlapping, which complicates quantitation, because slower migrating bands often have considerable contributions from the trailing edges of faster migrating bands. A method is described to accurately quantitate adjacent (32)P-bands, which relies on having a standard: a simple skewed-Gaussian curve from an analogous pure, single-component band (e.g., primer alone). This single-component scan/curve is superimposed on its corresponding band in an experimentally determined scan/curve containing multiple bands (e.g., generated in a primer-extension reaction); intensity exceeding the single-component scan/curve is attributed to other components (e.g., insertion products). Relative areas/intensities are determined via pixel analysis, from which relative molarity of components is computed. Common software is used. Commonly used alternative methods (e.g., drawing boxes around bands) are shown to be less accurate. Our method was used to study kinetics of dNTP primer-extension opposite a benzo[a]pyrene-N(2)-dG-adduct with four DNAPs, including Sulfolobus solfataricus Dpo4 and Sulfolobus acidocaldarius Dbh. Vmax/Km is similar for correct dCTP insertion with Dpo4 and Dbh. Compared to Dpo4, Dbh misinsertion is slower for dATP (∼20-fold), dGTP (∼110-fold) and dTTP (∼6-fold), due to decreases in Vmax. These findings provide support that Dbh is in the same Y-Family DNAP class as eukaryotic DNAP κ and bacterial DNAP IV, which accurately bypass N(2)-dG adducts, as well as establish the scan-method described herein as an accurate method to quantitate relative intensity of overlapping bands in a single lane, whether generated from (32)P-signals or by other means (e.g., staining).
Collapse
Affiliation(s)
- Gabriel Sholder
- Biology Department, Boston University, Boston, MA 02215, United States
| | - Edward L Loechler
- Biology Department, Boston University, Boston, MA 02215, United States.
| |
Collapse
|
60
|
Lior-Hoffmann L, Ding S, Geacintov NE, Zhang Y, Broyde S. Structural and dynamic characterization of polymerase κ's minor groove lesion processing reveals how adduct topology impacts fidelity. Biochemistry 2014; 53:5683-91. [PMID: 25148552 PMCID: PMC4159208 DOI: 10.1021/bi5007964] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
DNA
lesion bypass polymerases process different lesions with varying
fidelities, but the structural, dynamic, and mechanistic origins of
this phenomenon remain poorly understood. Human DNA polymerase κ
(Polκ), a member of the Y family of lesion bypass polymerases,
is specialized to bypass bulky DNA minor groove lesions in a predominantly
error-free manner, by housing them in its unique gap. We have investigated
the role of the unique Polκ gap and N-clasp structural features
in the fidelity of minor groove lesion processing with extensive molecular
modeling and molecular dynamics simulations to pinpoint their functioning
in lesion bypass. Here we consider the N2-dG covalent adduct derived from the carcinogenic aromatic amine,
2-acetylaminofluorene (dG-N2-AAF), that
is produced via the combustion of kerosene and diesel fuel. Our simulations
reveal how the spacious gap directionally accommodates the lesion
aromatic ring system as it transits through the stages of incorporation
of the predominant correct partner dCTP opposite the damaged guanine,
with preservation of local active site organization for nucleotidyl
transfer. Furthermore, flexibility in Polκ’s N-clasp
facilitates the significant misincorporation of dTTP opposite dG-N2-AAF via wobble pairing. Notably, we show that
N-clasp flexibility depends on lesion topology, being markedly reduced
in the case of the benzo[a]pyrene-derived major adduct
to N2-dG, whose bypass by Polκ is
nearly error-free. Thus, our studies reveal how Polκ’s
unique structural and dynamic properties can regulate its bypass fidelity
of polycyclic aromatic lesions and how the fidelity is impacted by
lesion structures.
Collapse
Affiliation(s)
- Lee Lior-Hoffmann
- Department of Biology and ‡Department of Chemistry, New York University , 100 Washington Square East, New York, New York 10003, United States
| | | | | | | | | |
Collapse
|
61
|
Zhai Q, Wang P, Cai Q, Wang Y. Syntheses and characterizations of the in vivo replicative bypass and mutagenic properties of the minor-groove O2-alkylthymidine lesions. Nucleic Acids Res 2014; 42:10529-37. [PMID: 25120272 PMCID: PMC4176383 DOI: 10.1093/nar/gku748] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Endogenous metabolism, environmental exposure, and treatment with some chemotherapeutic agents can all give rise to DNA alkylation, which can occur on the phosphate backbone as well as the ring nitrogen or exocyclic nitrogen and oxygen atoms of nucleobases. Previous studies showed that the minor-groove O2-alkylated thymidine (O2-alkyldT) lesions are poorly repaired and persist in mammalian tissues. In the present study, we synthesized oligodeoxyribonucleotides harboring seven O2-alkyldT lesions, with the alkyl group being a Me, Et, nPr, iPr, nBu, iBu or sBu, at a defined site and examined the impact of these lesions on DNA replication in Escherichia coli cells. Our results demonstrated that the replication bypass efficiencies of the O2-alkyldT lesions decreased with the chain length of the alkyl group, and these lesions directed promiscuous nucleotide misincorporation in E. coli cells. We also found that deficiency in Pol V, but not Pol II or Pol IV, led to a marked drop in bypass efficiencies for most O2-alkyldT lesions. We further showed that both Pol IV and Pol V were essential for the misincorporation of dCMP opposite these minor-groove DNA lesions, whereas only Pol V was indispensable for the T→A transversion introduced by these lesions. Depletion of Pol II, however, did not lead to any detectable alterations in mutation frequencies for any of the O2-alkyldT lesions. Thus, our study provided important new knowledge about the cytotoxic and mutagenic properties of the O2-alkyldT lesions and revealed the roles of the SOS-induced DNA polymerases in bypassing these lesions in E. coli cells.
Collapse
Affiliation(s)
- Qianqian Zhai
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Qian Cai
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA 92521, USA Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| |
Collapse
|
62
|
Ikeda M, Furukohri A, Philippin G, Loechler E, Akiyama MT, Katayama T, Fuchs RP, Maki H. DNA polymerase IV mediates efficient and quick recovery of replication forks stalled at N2-dG adducts. Nucleic Acids Res 2014; 42:8461-72. [PMID: 24957605 PMCID: PMC4117773 DOI: 10.1093/nar/gku547] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Escherichia coli DNA polymerase IV (Pol IV, also known as DinB) is a Y-family DNA polymerase capable of catalyzing translesion DNA synthesis (TLS) on certain DNA lesions, and accumulating data suggest that Pol IV may play an important role in copying various kinds of spontaneous DNA damage including N2-dG adducts and alkylated bases. Pol IV has a unique ability to coexist with Pol III on the same β clamp and to positively dissociate Pol III from β clamp in a concentration-dependent manner. Reconstituting the entire process of TLS in vitro using E. coli replication machinery and Pol IV, we observed that a replication fork stalled at (−)-trans-anti-benzo[a]pyrene-N2-dG lesion on the leading strand was efficiently and quickly recovered via two sequential switches from Pol III to Pol IV and back to Pol III. Our results suggest that TLS by Pol IV smoothes the way for the replication fork with minimal interruption.
Collapse
Affiliation(s)
- Mio Ikeda
- Division of Integrated Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Asako Furukohri
- Division of Integrated Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Gaelle Philippin
- CRCM, CNRS, UMR7258; Inserm, U1068; Institut Paoli-Calmettes; Aix-Marseille Universite, UM105, F13009 Marseille, France
| | - Edward Loechler
- Biology Department, Boston University, Boston, MA 02215, USA
| | - Masahiro Tatsumi Akiyama
- Division of Integrated Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Robert P Fuchs
- CRCM, CNRS, UMR7258; Inserm, U1068; Institut Paoli-Calmettes; Aix-Marseille Universite, UM105, F13009 Marseille, France
| | - Hisaji Maki
- Division of Integrated Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| |
Collapse
|
63
|
Petrova KV, Millsap AD, Stec DF, Rizzo CJ. Characterization of the deoxyguanosine-lysine cross-link of methylglyoxal. Chem Res Toxicol 2014; 27:1019-29. [PMID: 24801980 PMCID: PMC4060920 DOI: 10.1021/tx500068v] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Methylglyoxal is a mutagenic bis-electrophile that is produced endogenously from carbohydrate precursors. Methylglyoxal has been reported to induce DNA-protein cross-links (DPCs) in vitro and in cultured cells. Previous work suggests that these cross-links are formed between guanine and either lysine or cysteine side chains. However, the chemical nature of the methylglyoxal induced DPC have not been determined. We have examined the reaction of methylglyoxal, deoxyguanosine (dGuo), and Nα-acetyllysine (AcLys) and determined the structure of the cross-link to be the N2-ethyl-1-carboxamide with the lysine side chain amino group (1). The cross-link was identified by mass spectrometry and the structure confirmed by comparison to a synthetic sample. Further, the cross-link between methylglyoxal, dGuo, and a peptide (AcAVAGKAGAR) was also characterized. The mechanism of cross-link formation is likely to involve an Amadori rearrangement.
Collapse
Affiliation(s)
- Katya V Petrova
- Departments of Chemistry and Biochemistry, Center in Molecular Toxicology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University , Nashville, Tennessee 37235, United States
| | | | | | | |
Collapse
|
64
|
Song I, Kim EJ, Kim IH, Park EM, Lee KE, Shin JH, Guengerich FP, Choi JY. Biochemical characterization of eight genetic variants of human DNA polymerase κ involved in error-free bypass across bulky N(2)-guanyl DNA adducts. Chem Res Toxicol 2014; 27:919-30. [PMID: 24725253 DOI: 10.1021/tx500072m] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
DNA polymerase (pol) κ, one of the Y-family polymerases, has been shown to function in error-free translesion DNA synthesis (TLS) opposite the bulky N(2)-guanyl DNA lesions induced by many carcinogens such as polycyclic aromatic hydrocarbons. We analyzed the biochemical properties of eight reported human pol κ variants positioned in the polymerase core domain, using the recombinant pol κ (residues 1-526) protein and the DNA template containing an N(2)-CH2(9-anthracenyl)G (N(2)-AnthG). The truncation R219X was devoid of polymerase activity, and the E419G and Y432S variants showed much lower polymerase activity than wild-type pol κ. In steady-state kinetic analyses, E419G and Y432S displayed 20- to 34-fold decreases in kcat/Km for dCTP insertion opposite G and N(2)-AnthG compared to that of wild-type pol κ. The L21F, I39T, and D189G variants, as well as E419G and Y432S, displayed 6- to 22-fold decreases in kcat/Km for next-base extension from C paired with N(2)-AnthG, compared to that of wild-type pol κ. The defective Y432S variant had 4- to 5-fold lower DNA-binding affinity than wild-type, while a slightly more efficient S423R variant possessed 2- to 3-fold higher DNA-binding affinity. These results suggest that R219X abolishes and the E419G, Y432S, L21F, I39T, and D189G variations substantially impair the TLS ability of pol κ opposite bulky N(2)-G lesions in the insertion step opposite the lesion and/or the subsequent extension step, raising the possibility that certain nonsynonymous pol κ genetic variations translate into individual differences in susceptibility to genotoxic carcinogens.
Collapse
Affiliation(s)
- Insil Song
- Division of Pharmacology, Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine , Suwon, Gyeonggi-do 440-746, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
65
|
Shrivastav N, Fedeles BI, Li D, Delaney JC, Frick LE, Foti JJ, Walker GC, Essigmann JM. A chemical genetics analysis of the roles of bypass polymerase DinB and DNA repair protein AlkB in processing N2-alkylguanine lesions in vivo. PLoS One 2014; 9:e94716. [PMID: 24733044 PMCID: PMC3986394 DOI: 10.1371/journal.pone.0094716] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 03/18/2014] [Indexed: 01/06/2023] Open
Abstract
DinB, the E. coli translesion synthesis polymerase, has been shown to bypass several N2-alkylguanine adducts in vitro, including N2-furfurylguanine, the structural analog of the DNA adduct formed by the antibacterial agent nitrofurazone. Recently, it was demonstrated that the Fe(II)- and α-ketoglutarate-dependent dioxygenase AlkB, a DNA repair enzyme, can dealkylate in vitro a series of N2-alkyguanines, including N2-furfurylguanine. The present study explored, head to head, the in vivo relative contributions of these two DNA maintenance pathways (replicative bypass vs. repair) as they processed a series of structurally varied, biologically relevant N2-alkylguanine lesions: N2-furfurylguanine (FF), 2-tetrahydrofuran-2-yl-methylguanine (HF), 2-methylguanine, and 2-ethylguanine. Each lesion was chemically synthesized and incorporated site-specifically into an M13 bacteriophage genome, which was then replicated in E. coli cells deficient or proficient for DinB and AlkB (4 strains in total). Biochemical tools were employed to analyze the relative replication efficiencies of the phage (a measure of the bypass efficiency of each lesion) and the base composition at the lesion site after replication (a measure of the mutagenesis profile of each lesion). The main findings were: 1) Among the lesions studied, the bulky FF and HF lesions proved to be strong replication blocks when introduced site-specifically on a single-stranded vector in DinB deficient cells. This toxic effect disappeared in the strains expressing physiological levels of DinB. 2) AlkB is known to repair N2-alkylguanine lesions in vitro; however, the presence of AlkB showed no relief from the replication blocks induced by FF and HF in vivo. 3) The mutagenic properties of the entire series of N2-alkyguanines adducts were investigated in vivo for the first time. None of the adducts were mutagenic under the conditions evaluated, regardless of the DinB or AlkB cellular status. Taken together, the data indicated that the cellular pathway to combat bulky N2-alkylguanine DNA adducts was DinB-dependent lesion bypass.
Collapse
Affiliation(s)
- Nidhi Shrivastav
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Bogdan I. Fedeles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Deyu Li
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - James C. Delaney
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Lauren E. Frick
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - James J. Foti
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - John M. Essigmann
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
66
|
Zhai Q, Wang P, Wang Y. Cytotoxic and mutagenic properties of regioisomeric O²-, N3- and O⁴-ethylthymidines in bacterial cells. Carcinogenesis 2014; 35:2002-6. [PMID: 24710626 DOI: 10.1093/carcin/bgu085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exposure to environmental agents and endogenous metabolism can both give rise to DNA alkylation. Thymine is known to be alkylated at O(2), N3 and O(4) positions; however, it remains poorly explored how the regioisomeric alkylated thymidine lesions compromise the flow of genetic information by perturbing DNA replication in cells. Herein, we assessed the differential recognition of the regioisomeric O(2)-, N3- and O(4)-ethylthymidine (O(2)-, N3- and O(4)-EtdT) by the DNA replication machinery of Escherichia coli cells. We found that O(4)-EtdT did not inhibit appreciably DNA replication, whereas O(2)- and N3-EtdT were strongly blocking to DNA replication. In addition, O(4)-EtdT induced a very high frequency of T→C mutation, whereas nucleotide incorporation opposite O(2)- and N3-EtdT was promiscuous. Replication experiments with the use of polymerase-deficient cells revealed that Pol V constituted the major polymerase for the mutagenic bypass of all three EtdT lesions, though Pol IV also contributed to the T→G mutation induced by O(2)- and N3-EtdT. The distinct cytotoxic and mutagenic properties of the three regioisomeric lesions could be attributed to their unique chemical properties.
Collapse
Affiliation(s)
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Yinsheng Wang
- Department of Chemistry and Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, USA
| |
Collapse
|
67
|
Variants of mouse DNA polymerase κ reveal a mechanism of efficient and accurate translesion synthesis past a benzo[a]pyrene dG adduct. Proc Natl Acad Sci U S A 2014; 111:1789-94. [PMID: 24449898 DOI: 10.1073/pnas.1324168111] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA polymerase κ (Polκ) is the only known Y-family DNA polymerase that bypasses the 10S (+)-trans-anti-benzo[a]pyrene diol epoxide (BPDE)-N(2)-deoxyguanine adducts efficiently and accurately. The unique features of Polκ, a large structure gap between the catalytic core and little finger domain and a 90-residue addition at the N terminus known as the N-clasp, may give rise to its special translesion capability. We designed and constructed two mouse Polκ variants, which have reduced gap size on both sides [Polκ Gap Mutant (PGM) 1] or one side flanking the template base (PGM2). These Polκ variants are nearly as efficient as WT in normal DNA synthesis, albeit with reduced accuracy. However, PGM1 is strongly blocked by the 10S (+)-trans-anti-BPDE-N(2)-dG lesion. Steady-state kinetic measurements reveal a significant reduction in efficiency of dCTP incorporation opposite the lesion by PGM1 and a moderate reduction by PGM2. Consistently, Polκ-deficient cells stably complemented with PGM1 GFP-Polκ remained hypersensitive to BPDE treatment, and complementation with WT or PGM2 GFP-Polκ restored BPDE resistance. Furthermore, deletion of the first 51 residues of the N-clasp in mouse Polκ (mPolκ(52-516)) leads to reduced polymerization activity, and the mutant PGM2(52-516) but not PGM1(52-516) can partially compensate the N-terminal deletion and restore the catalytic activity on normal DNA. However, neither WT nor PGM2 mPolκ(52-516) retains BPDE bypass activity. We conclude that the structural gap physically accommodates the bulky aromatic adduct and the N-clasp is essential for the structural integrity and flexibility of Polκ during translesion synthesis.
Collapse
|
68
|
Andersen N, Wang P, Wang Y. Replication across regioisomeric ethylated thymidine lesions by purified DNA polymerases. Chem Res Toxicol 2013; 26:1730-8. [PMID: 24134187 DOI: 10.1021/tx4002995] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Causal links exist between smoking cigarettes and cancer development. Some genotoxic agents in cigarette smoke are capable of alkylating nucleobases in DNA, and higher levels of ethylated DNA lesions were observed in smokers than in nonsmokers. In this study, we examined comprehensively how the regioisomeric O(2)-, N3-, and O(4)-ethylthymidine (O(2)-, N3-, and O(4)-EtdT, respectively) perturb DNA replication mediated by purified human DNA polymerases (hPols) η, κ, and ι, yeast DNA polymerase ζ (yPol ζ), and the exonuclease-free Klenow fragment (Kf(-)) of Escherichia coli DNA polymerase I. Our results showed that hPol η and Kf(-) could bypass all three lesions and generate full-length replication products, whereas hPol ι stalled after inserting a single nucleotide opposite the lesions. Bypass conducted by hPol κ and yPol ζ differed markedly among the three lesions. Consistent with its known ability to efficiently bypass the minor groove N(2)-substituted 2'-deoxyguanosine lesions, hPol κ was able to bypass O(2)-EtdT, though it experienced great difficulty in bypassing N3-EtdT and O(4)-EtdT. yPol ζ was only modestly blocked by O(4)-EtdT, but the polymerase was strongly hindered by O(2)-EtdT and N3-EtdT. LC-MS/MS analysis of the replication products revealed that DNA synthesis opposite O(4)-EtdT was highly error-prone, with dGMP being preferentially inserted, while the presence of O(2)-EtdT and N3-EtdT in template DNA directed substantial frequencies of misincorporation of dGMP and, for hPol ι and Kf(-), dTMP. Thus, our results suggested that O(2)-EtdT and N3-EtdT may also contribute to the AT → TA and AT → GC mutations observed in cells and tissues of animals exposed to ethylating agents.
Collapse
Affiliation(s)
- Nisana Andersen
- Department of Chemistry and ‡Environmental Toxicology Graduate Program, University of California , Riverside, California 92521-0403, United States
| | | | | |
Collapse
|
69
|
Xing XW, Liu YL, Vargas M, Wang Y, Feng YQ, Zhou X, Yuan BF. Mutagenic and cytotoxic properties of oxidation products of 5-methylcytosine revealed by next-generation sequencing. PLoS One 2013; 8:e72993. [PMID: 24066027 PMCID: PMC3774748 DOI: 10.1371/journal.pone.0072993] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/23/2013] [Indexed: 11/19/2022] Open
Abstract
5-methylcytosine (5-mC) can be sequentially oxidized to 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine (5-foC), and finally to 5-carboxylcytosine (5-caC), which is thought to function in active DNA cytosine demethylation in mammals. Although the roles of 5-mC in epigenetic regulation of gene expression are well established, the effects of 5-hmC, 5-foC and 5-caC on DNA replication remain unclear. Here we report a systematic study on how these cytosine derivatives (5-hmC, 5-foC and 5-caC) perturb the efficiency and accuracy of DNA replication using shuttle vector technology in conjugation with next-g
sequencing. Our results demonstrated that, in Escherichia coli cells, all the cytosine derivatives could induce CT transition mutation at frequencies of 0.17%–1.12%, though no effect on replication efficiency was observed. These findings provide an important new insight on the potential mutagenic properties of cytosine derivatives occurring as the intermediates of DNA demethylation.
Collapse
Affiliation(s)
- Xi-Wen Xing
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, P.R. China
| | - Yu-Li Liu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, P.R. China
| | - Mario Vargas
- Department of Chemistry, University of California Riverside, Riverside, California, United States of America
| | - Yinsheng Wang
- Department of Chemistry, University of California Riverside, Riverside, California, United States of America
| | - Yu-Qi Feng
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, P.R. China
| | - Xiang Zhou
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, P.R. China
- * E-mail: (BFY); (XZ)
| | - Bi-Feng Yuan
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, P.R. China
- * E-mail: (BFY); (XZ)
| |
Collapse
|
70
|
Walsh JM, Ippoliti PJ, Ronayne EA, Rozners E, Beuning PJ. Discrimination against major groove adducts by Y-family polymerases of the DinB subfamily. DNA Repair (Amst) 2013; 12:713-22. [PMID: 23791649 DOI: 10.1016/j.dnarep.2013.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 10/26/2022]
Abstract
Y-family DNA polymerases bypass DNA adducts in a process known as translesion synthesis (TLS). Y-family polymerases make contacts with the minor groove side of the DNA substrate at the nascent base pair. The Y-family polymerases also contact the DNA major groove via the unique little finger domain, but they generally lack contacts with the major groove at the nascent base pair. Escherichia coli DinB efficiently and accurately copies certain minor groove guanosine adducts. In contrast, we previously showed that the presence in the DNA template of the major groove-modified base 1,3-diaza-2-oxophenothiazine (tC) inhibits the activity of E. coli DinB. Even when the DNA primer is extended up to three nucleotides beyond the site of the tC analog, DinB activity is strongly inhibited. These findings prompted us to investigate discrimination against other major groove modifications by DinB and its orthologs. We chose a set of pyrimidines and purines with modifications in the major groove and determined the activity of DinB and several orthologs with these substrates. DinB, human pol kappa, and Sulfolobus solfataricus Dpo4 show differing specificities for the major groove adducts pyrrolo-dC, dP, N(6)-furfuryl-dA, and etheno-dA. In general, DinB was least efficient for bypass of all of these major groove adducts, whereas Dpo4 was most efficient. DinB activity was essentially completely inhibited by the presence of etheno-dA, while pol kappa activity was strongly inhibited. All three of these DNA polymerases were able to bypass N(6)-furfuryl-dA with modest efficiency, with DinB being the least efficient. We also determined that the R35A variant of DinB enhances bypass of N(6)-furfuryl-dA but not etheno-dA. In sum, we find that whereas DinB is specific for bypass of minor groove adducts, it is specifically inhibited by major groove DNA modifications.
Collapse
Affiliation(s)
- Jason M Walsh
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
71
|
Ozyamak E, de Almeida C, de Moura APS, Miller S, Booth IR. Integrated stress response of Escherichia coli to methylglyoxal: transcriptional readthrough from the nemRA operon enhances protection through increased expression of glyoxalase I. Mol Microbiol 2013; 88:936-50. [PMID: 23646895 PMCID: PMC3739934 DOI: 10.1111/mmi.12234] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 12/02/2022]
Abstract
Methylglyoxal (MG) elicits activation of K+ efflux systems to protect cells against the toxicity of the electrophile. ChIP-chip targeting RNA polymerase, supported by a range of other biochemical measurements and mutant creation, was used to identify genes transcribed in response to MG and which complement this rapid response. The SOS DNA repair regulon is induced at cytotoxic levels of MG, even when exposure to MG is transient. Glyoxalase I alone among the core MG protective systems is induced in response to MG exposure. Increased expression is an indirect consequence of induction of the upstream nemRA operon, encoding an enzyme system that itself does not contribute to MG detoxification. Moreover, this induction, via nemRA only occurs when cells are exposed to growth inhibitory concentrations of MG. We show that the kdpFABCDE genes are induced and that this expression occurs as a result of depletion of cytoplasmic K+ consequent upon activation of the KefGB K+ efflux system. Finally, our analysis suggests that the transcriptional changes in response to MG are a culmination of the damage to DNA and proteins, but that some integrate specific functions, such as DNA repair, to augment the allosteric activation of the main protective system, KefGB.
Collapse
Affiliation(s)
- Ertan Ozyamak
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK.
| | | | | | | | | |
Collapse
|
72
|
Abstract
The structural features that enable replicative DNA polymerases to synthesize DNA rapidly and accurately also limit their ability to copy damaged DNA. Direct replication of DNA damage is termed translesion synthesis (TLS), a mechanism conserved from bacteria to mammals and executed by an array of specialized DNA polymerases. This chapter examines how these translesion polymerases replicate damaged DNA and how they are regulated to balance their ability to replicate DNA lesions with the risk of undesirable mutagenesis. It also discusses how TLS is co-opted to increase the diversity of the immunoglobulin gene hypermutation and the contribution it makes to the mutations that sculpt the genome of cancer cells.
Collapse
Affiliation(s)
- Julian E Sale
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
| |
Collapse
|
73
|
A quantitative assay for assessing the effects of DNA lesions on transcription. Nat Chem Biol 2013; 8:817-22. [PMID: 22902614 PMCID: PMC3509257 DOI: 10.1038/nchembio.1046] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 06/22/2012] [Indexed: 12/12/2022]
Abstract
Most mammalian cells in nature are quiescent but actively transcribing mRNA for normal physiological processes; thus, it is important to investigate how endogenous and exogenous DNA damage compromises transcription in cells. Here we describe a new competitive transcription and adduct bypass (CTAB) assay to determine the effects of DNA lesions on the fidelity and efficiency of transcription. Using this strategy, we demonstrate that the oxidatively induced lesions 8,5'-cyclo-2'-deoxyadenosine (cdA) and 8,5'-cyclo-2'-deoxyguanosine (cdG) and the methylglyoxal-induced lesion N(2)-(1-carboxyethyl)-2'-deoxyguanosine (N(2)-CEdG) strongly inhibited transcription in vitro and in mammalian cells. In addition, cdA and cdG, but not N(2)-CEdG, induced transcriptional mutagenesis in vitro and in vivo. Furthermore, when located on the template DNA strand, all examined lesions were primarily repaired by transcription-coupled nucleotide excision repair in mammalian cells. This newly developed CTAB assay should be generally applicable for quantitatively assessing how other DNA lesions affect DNA transcription in vitro and in cells.
Collapse
|
74
|
Tegginamath G, Kamble RR, Taj T, Kattimani PP, Meti GY. Synthesis of novel imidazo[2,1-b][1,3,4]thiadiazoles appended to sydnone as anticancer agents. Med Chem Res 2013. [DOI: 10.1007/s00044-012-0441-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
75
|
A single residue unique to DinB-like proteins limits formation of the polymerase IV multiprotein complex in Escherichia coli. J Bacteriol 2013; 195:1179-93. [PMID: 23292773 DOI: 10.1128/jb.01349-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The activity of DinB is governed by the formation of a multiprotein complex (MPC) with RecA and UmuD. We identified two highly conserved surface residues in DinB, cysteine 66 (C66) and proline 67 (P67). Mapping on the DinB tertiary structure suggests these are noncatalytic, and multiple-sequence alignments indicate that they are unique among DinB-like proteins. To investigate the role of the C66-containing surface in MPC formation, we constructed the dinB(C66A) derivative. We found that DinB(C66A) copurifies with its interacting partners, RecA and UmuD, to a greater extent than DinB. Notably, copurification of RecA with DinB is somewhat enhanced in the absence of UmuD and is further increased for DinB(C66A). In vitro pulldown assays also indicate that DinB(C66A) binds RecA and UmuD better than DinB. We note that the increased affinity of DinB(C66A) for UmuD is RecA dependent. Thus, the C66-containing binding surface appears to be critical to modulate interaction with UmuD, and particularly with RecA. Expression of dinB(C66A) from the chromosome resulted in detectable differences in dinB-dependent lesion bypass fidelity and homologous recombination. Study of this DinB derivative has revealed a key surface on DinB, which appears to modulate the strength of MPC binding, and has suggested a binding order of RecA and UmuD to DinB. These findings will ultimately permit the manipulation of these enzymes to deter bacterial antibiotic resistance acquisition and to gain insights into cancer development in humans.
Collapse
|
76
|
Mori T, Nakamura T, Okazaki N, Furukohri A, Maki H, Akiyama MT. Escherichia coli DinB inhibits replication fork progression without significantly inducing the SOS response. Genes Genet Syst 2012; 87:75-87. [PMID: 22820381 DOI: 10.1266/ggs.87.75] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The SOS response is readily triggered by replication fork stalling caused by DNA damage or a dysfunctional replicative apparatus in Escherichia coli cells. E. coli dinB encodes DinB DNA polymerase and its expression is upregulated during the SOS response. DinB catalyzes translesion DNA synthesis in place of a replicative DNA polymerase III that is stalled at a DNA lesion. We showed previously that DNA replication was suppressed without exogenous DNA damage in cells overproducing DinB. In this report, we confirm that this was due to a dose-dependent inhibition of ongoing replication forks by DinB. Interestingly, the DinB-overproducing cells did not significantly induce the SOS response even though DNA replication was perturbed. RecA protein is activated by forming a nucleoprotein filament with single-stranded DNA, which leads to the onset of the SOS response. In the DinB-overproducing cells, RecA was not activated to induce the SOS response. However, the SOS response was observed after heat-inducible activation in strain recA441 (encoding a temperature-sensitive RecA) and after replication blockage in strain dnaE486 (encoding a temperature-sensitive catalytic subunit of the replicative DNA polymerase III) at a non-permissive temperature when DinB was overproduced in these cells. Furthermore, since catalytically inactive DinB could avoid the SOS response to a DinB-promoted fork block, it is unlikely that overproduced DinB takes control of primer extension and thus limits single-stranded DNA. These observations suggest that DinB possesses a feature that suppresses DNA replication but does not abolish the cell's capacity to induce the SOS response. We conclude that DinB impedes replication fork progression in a way that does not activate RecA, in contrast to obstructive DNA lesions and dysfunctional replication machinery.
Collapse
Affiliation(s)
- Tetsuya Mori
- Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | | | | | | | | | | |
Collapse
|
77
|
Walsh JM, Parasuram R, Rajput PR, Rozners E, Ondrechen MJ, Beuning PJ. Effects of non-catalytic, distal amino acid residues on activity of E. coli DinB (DNA polymerase IV). ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:766-776. [PMID: 23034734 DOI: 10.1002/em.21730] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 08/08/2012] [Accepted: 08/06/2012] [Indexed: 06/01/2023]
Abstract
DinB is one of two Y family polymerases in E. coli and is involved in copying damaged DNA. DinB is specialized to bypass deoxyguanosine adducts that occur at the N(2) position, with its cognate lesion being the furfuryl adduct. Active site residues have been identified that make contact with the substrate and carry out deoxynucleotide triphosphate (dNTP) addition to the growing DNA strand. In DNA polymerases, these include negatively charged aspartate and glutamate residues (D8, D103, and E104 in E. coli DNA polymerase IV DinB). These residues position the essential magnesium ions correctly to facilitate nucleophilic attack by the primer hydroxyl group on the α-phosphate group of the incoming dNTP. To study the contribution of DinB residues to lesion bypass, the computational methods THEMATICS and POOL were employed. These methods correctly predict the known active site residues, as well as other residues known to be important for activity. In addition, these methods predict other residues involved in substrate binding as well as more remote residues. DinB variants with mutations at the predicted positions were constructed and assayed for bypass of the N(2) -furfuryl-dG lesion. We find a wide range of effects of predicted residues, including some mutations that abolish damage bypass. Moreover, most of the DinB variants constructed are unable to carry out the extension step of lesion bypass. The use of computational prediction methods represents another tool that will lead to a more complete understanding of translesion DNA synthesis.
Collapse
Affiliation(s)
- Jason M Walsh
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | | | | | | | | | | |
Collapse
|
78
|
Chandani S, Loechler EL. Structural model of the Y-Family DNA polymerase V/RecA mutasome. J Mol Graph Model 2012; 39:133-44. [PMID: 23266508 DOI: 10.1016/j.jmgm.2012.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/19/2012] [Accepted: 09/29/2012] [Indexed: 11/18/2022]
Abstract
To synthesize past DNA damaged by chemicals or radiation, cells have lesion bypass DNA polymerases (DNAPs), most of which are in the Y-Family. One class of Y-Family DNAPs includes DNAP η in eukaryotes and DNAP V in bacteria, which have low fidelity when replicating undamaged DNA. In Escherchia coli, DNAP V is carefully regulated to insure it is active for lesion bypass only, and one mode of regulation involves interaction of the polymerase subunit (UmuC) and two regulatory subunits (UmuD') with a RecA-filament bound to ss-DNA. Taking a docking approach, ∼150,000 unique orientations involving UmuC, UmuD' and RecA were evaluated to generate models, one of which was judged best able to rationalize the following published findings. (1) In the UmuD'(2)C/RecA-filament model, R64-UmuC interacts with S117-RecA, which is known to be at the UmuC/RecA interface. (2) At the model's UmuC/RecA interface, UmuC has three basic amino acids (K59/R63/R64) that anchor it to RecA. No other Y-Family DNAP has three basic amino acids clustered in this region, making it a plausible site for UmuC to form its unique interaction with RecA. (3) In the model, residues N32/N33/D34 of UmuC form a second interface with RecA, which is consistent with published findings. (4) Active UmuD' is generated when 24 amino acids in the N-terminal tail of UmuD are proteolyzed, which occurs when UmuD(2)C binds the RecA-filament. When UmuD is included in an UmuD(2)C/RecA-filament model, plausible UmuD/RecA contacts guide the UmuD cleavage site (C24/G25) into the UmuD proteolysis active site (S60/K97). One contact involves E11-UmuD interacting with R243-RecA, where the latter is known to be important for UmuD cleavage. (5) The UmuD(2)C/RecA-filament model rationalizes published findings that at least some UmuD-to-UmuD' cleavage occurs intermolecularly. (6) Active DNAP V is known to be the heterotetramer UmuD'(2)C/RecA, a model of which can be generated by a simple rearrangement of the RecA monomer at the 3'-end of the RecA-filament. The rearranged UmuD'(2)C/RecA model rationalizes published findings about UmuD' residues in proximity to RecA. In summary, docking and molecular simulations are used to develop an UmuD'(2)C/RecA model, whose structure rationalizes much of the known properties of the active form of DNA polymerase V.
Collapse
Affiliation(s)
- Sushil Chandani
- Biology Department, Boston University, Boston, MA 02215, United States
| | | |
Collapse
|
79
|
Andersen N, Wang J, Wang P, Jiang Y, Wang Y. In-vitro replication studies on O(2)-methylthymidine and O(4)-methylthymidine. Chem Res Toxicol 2012; 25:2523-31. [PMID: 23113558 PMCID: PMC3502631 DOI: 10.1021/tx300325q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
O(2)- and O(4)-methylthymidine (O(2)-MdT and O(4)-MdT) can be induced in tissues of laboratory animals exposed with N-methyl-N-nitrosourea, a known carcinogen. These two O-methylated DNA adducts have been shown to be poorly repaired and may contribute to the mutations arising from exposure to DNA methylating agents. Here, in vitro replication studies with duplex DNA substrates containing site-specifically incorporated O(2)-MdT and O(4)-MdT showed that both lesions blocked DNA synthesis mediated by three different DNA polymerases, including the exonuclease-free Klenow fragment of Escherichia coli DNA polymerase I (Kf(-)), human DNA polymerase κ (pol κ), and Saccharomyces cerevisiae DNA polymerase η (pol η). Results from steady-state kinetic measurements and LC-MS/MS analysis of primer extension products revealed that Kf(-) and pol η preferentially incorporated the correct nucleotide (dAMP) opposite O(2)-MdT, while O(4)-MdT primarily directed dGMP misincorporation. While steady-state kinetic experiments showed that pol κ-mediated nucleotide insertion opposite O(2)-MdT and O(4)-MdT is highly promiscuous, LC-MS/MS analysis of primer extension products demonstrated that pol κ favorably incorporated the incorrect dGMP opposite both lesions. Our results underscored the limitation of the steady-state kinetic assay in determining how DNA lesions compromise DNA replication in vitro. In addition, the results from our study revealed that, if left unrepaired, O-methylated thymidine lesions may constitute important sources of nucleobase substitutions emanating from exposure to alkylating agents.
Collapse
Affiliation(s)
- Nisana Andersen
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Jianshuang Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403
| | - Yong Jiang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403
| |
Collapse
|
80
|
Multiple strategies for translesion synthesis in bacteria. Cells 2012; 1:799-831. [PMID: 24710531 PMCID: PMC3901139 DOI: 10.3390/cells1040799] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 09/29/2012] [Accepted: 09/30/2012] [Indexed: 12/16/2022] Open
Abstract
Damage to DNA is common and can arise from numerous environmental and endogenous sources. In response to ubiquitous DNA damage, Y-family DNA polymerases are induced by the SOS response and are capable of bypassing DNA lesions. In Escherichia coli, these Y-family polymerases are DinB and UmuC, whose activities are modulated by their interaction with the polymerase manager protein UmuD. Many, but not all, bacteria utilize DinB and UmuC homologs. Recently, a C-family polymerase named ImuC, which is similar in primary structure to the replicative DNA polymerase DnaE, was found to be able to copy damaged DNA and either carry out or suppress mutagenesis. ImuC is often found with proteins ImuA and ImuB, the latter of which is similar to Y‑family polymerases, but seems to lack the catalytic residues necessary for polymerase activity. This imuAimuBimuC mutagenesis cassette represents a widespread alternative strategy for translesion synthesis and mutagenesis in bacteria. Bacterial Y‑family and ImuC DNA polymerases contribute to replication past DNA damage and the acquisition of antibiotic resistance.
Collapse
|
81
|
Swanson AL, Wang J, Wang Y. Accurate and efficient bypass of 8,5'-cyclopurine-2'-deoxynucleosides by human and yeast DNA polymerase η. Chem Res Toxicol 2012; 25:1682-91. [PMID: 22768970 DOI: 10.1021/tx3001576] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reactive oxygen species (ROS), which can be produced during normal aerobic metabolism, can induce the formation of tandem DNA lesions, including 8,5'-cyclo-2'-deoxyadenosine (cyclo-dA) and 8,5'-cyclo-2'-deoxyguanosine (cyclo-dG). Previous studies have shown that cyclo-dA and cyclo-dG accumulate in cells and can block mammalian RNA polymerase II and replicative DNA polymerases. Here, we used primer extension and steady-state kinetic assays to examine the efficiency and fidelity for polymerase η to insert nucleotides opposite, and extend primer past, these cyclopurine lesions. We found that Saccharomyces cerevisiae and human polymerase η inserted 2'-deoxynucleotides opposite cyclo-dA, cyclo-dG and their adjacent 5' nucleosides at fidelities and efficiencies that were similar to those of their respective undamaged nucleosides. Moreover, the yeast enzyme exhibited similar processivity in DNA synthesis on templates housing a cyclo-dA or cyclo-dG to those carrying an unmodified dA or dG; the human polymerase, however, dissociated from the primer-template complex after inserting one or two additional nucleotides after the lesion. Pol η's accurate and efficient bypass of cyclo-dA and cyclo-dG indicates that this polymerase is likely responsible for error-free bypass of these lesions, whereas mutagenic bypass of these lesions may involve other translesion synthesis DNA polymerases. Together, our results suggested that pol η may have an additional function in cells, i.e., to alleviate the cellular burden of endogenously induced DNA lesions, including cyclo-dA and cyclo-dG.
Collapse
Affiliation(s)
- Ashley L Swanson
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403, USA
| | | | | |
Collapse
|
82
|
Baxter JC, Sutton MD. Evidence for roles of the Escherichia coli Hda protein beyond regulatory inactivation of DnaA. Mol Microbiol 2012; 85:648-68. [PMID: 22716942 DOI: 10.1111/j.1365-2958.2012.08129.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ATP-bound form of the Escherichia coli DnaA protein binds 'DnaA boxes' present in the origin of replication (oriC) and operator sites of several genes, including dnaA, to co-ordinate their transcription with initiation of replication. The Hda protein, together with the β sliding clamp, stimulates the ATPase activity of DnaA via a process termed regulatory inactivation of DnaA (RIDA), to regulate the activity of DnaA in DNA replication. Here, we used the mutant dnaN159 strain, which expresses the β159 clamp protein, to gain insight into how the actions of Hda are co-ordinated with replication. Elevated expression of Hda impeded growth of the dnaN159 strain in a Pol II- and Pol IV-dependent manner, suggesting a role for Hda managing the actions of these Pols. In a wild-type strain, elevated levels of Hda conferred sensitivity to nitrofurazone, and suppressed the frequency of -1 frameshift mutations characteristic of Pol IV, while loss of hda conferred cold sensitivity. Using the dnaN159 strain, we identified 24 novel hda alleles, four of which supported E. coli viability despite their RIDA defect. Taken together, these findings suggest that although one or more Hda functions are essential for cell viability, RIDA may be dispensable.
Collapse
Affiliation(s)
- Jamie C Baxter
- Department of Biochemistry, The School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | | |
Collapse
|
83
|
Kuban W, Vaisman A, McDonald JP, Karata K, Yang W, Goodman MF, Woodgate R. Escherichia coli UmuC active site mutants: effects on translesion DNA synthesis, mutagenesis and cell survival. DNA Repair (Amst) 2012; 11:726-32. [PMID: 22784977 DOI: 10.1016/j.dnarep.2012.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 11/17/2022]
Abstract
Escherichia coli polymerase V (pol V/UmuD(2)'C) is a low-fidelity DNA polymerase that has recently been shown to avidly incorporate ribonucleotides (rNTPs) into undamaged DNA. The fidelity and sugar selectivity of pol V can be modified by missense mutations around the "steric gate" of UmuC. Here, we analyze the ability of three steric gate mutants of UmuC to facilitate translesion DNA synthesis (TLS) of a cyclobutane pyrimidine dimer (CPD) in vitro, and to promote UV-induced mutagenesis and cell survival in vivo. The pol V (UmuC_F10L) mutant discriminates against rNTP and incorrect dNTP incorporation much better than wild-type pol V and although exhibiting a reduced ability to bypass a CPD in vitro, does so with high-fidelity and consequently produces minimal UV-induced mutagenesis in vivo. In contrast, pol V (UmuC_Y11A) readily misincorporates both rNTPs and dNTPs during efficient TLS of the CPD in vitro. However, cells expressing umuD'C(Y11A) were considerably more UV-sensitive and exhibited lower levels of UV-induced mutagenesis than cells expressing wild-type umuD'C or umuD'C(Y11F). We propose that the increased UV-sensitivity and reduced UV-mutability of umuD'C(Y11A) is due to excessive incorporation of rNTPs during TLS that are subsequently targeted for repair, rather than an inability to traverse UV-induced lesions.
Collapse
Affiliation(s)
- Wojciech Kuban
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | | | | | | | | | | | | |
Collapse
|
84
|
Cohen SE, Walker GC. New discoveries linking transcription to DNA repair and damage tolerance pathways. Transcription 2012; 2:37-40. [PMID: 21326909 DOI: 10.4161/trns.2.1.14228] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 11/17/2010] [Accepted: 11/17/2010] [Indexed: 01/27/2023] Open
Abstract
In Escherichia coli, the transcription elongation factor NusA is associated with all elongating RNA polymerases where it functions in transcription termination and antitermination. Here, we review our recent results implicating NusA in the recruitment of DNA repair and damage tolerance mechanisms to sites of stalled transcription complexes.
Collapse
Affiliation(s)
- Susan E Cohen
- Department of Biology, Massachusetts Institute of Technology, Cambridge, USA
| | | |
Collapse
|
85
|
Swanson AL, Wang J, Wang Y. In vitro replication studies of carboxymethylated DNA lesions with Saccharomyces cerevisiae polymerase η. Biochemistry 2011; 50:7666-73. [PMID: 21809836 DOI: 10.1021/bi2007417] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Humans are exposed to N-nitroso compounds (NOCs) both endogenously and exogenously from a number of environmental sources, and NOCs are both mutagenic and carcinogenic. After metabolic activation, some NOCs can induce carboxymethylation of nucleobases through a diazoacetate intermediate, which could give rise to p53 mutations similar to those seen in human gastrointestinal cancers. It was previously found that the growth of polymerase η-deficient human cells was inhibited by treatment with azaserine, a DNA carboxymethylation agent, suggesting the importance of this polymerase in bypassing the azaserine-induced carboxymethylated DNA lesions. In this study, we examined how carboxymethylated DNA lesions, which included N(6)-carboxymethyl-2'-deoxyadenosine (N(6)-CMdA), N(4)-carboxymethyl-2'-deoxycytidine (N(4)-CMdC), N3-carboxymethylthymidine (N3-CMdT), and O(4)-carboxymethylthymidine (O(4)-CMdT), perturbed the efficiency and fidelity of DNA replication mediated by Saccharomyces cerevisiae polymerase η (pol η). Our results from steady-state kinetic assay showed that pol η could readily bypass and extend past N(6)-CMdA and incorporated the correct nucleotides opposite the lesion and its neighboring 5'-nucleoside with high efficiency. By contrast, the polymerase could bypass N(4)-CMdC inefficiently, with substantial misincorporation of dCMP followed by dAMP, though pol η could extend past the lesion with high fidelity and efficiency when dGMP was incorporated opposite the lesion. On the other hand, yeast pol η experienced great difficulty in bypassing O(4)-CMdT and N3-CMdT, and the polymerase inserted preferentially the incorrect dGMP opposite these two DNA lesions; the extension step, nevertheless, occurred with high fidelity and efficiency when the correct dAMP was opposite the lesion, as opposed to the preferentially incorporated incorrect dGMP. These results suggest that these lesions may contribute significantly to diazoacetate-induced mutations and those in the p53 gene observed in human gastrointestinal tumors.
Collapse
Affiliation(s)
- Ashley L Swanson
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | | | | |
Collapse
|
86
|
Discrimination against the Cytosine Analog tC by Escherichia coli DNA Polymerase IV DinB. J Mol Biol 2011; 409:89-100. [DOI: 10.1016/j.jmb.2011.03.069] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/27/2011] [Accepted: 03/30/2011] [Indexed: 01/30/2023]
|
87
|
Breyer V, Becker CM, Pischetsrieder M. Intracellular glycation of nuclear DNA, mitochondrial DNA, and cytosolic proteins during senescence-like growth arrest. DNA Cell Biol 2011; 30:681-9. [PMID: 21612395 DOI: 10.1089/dna.2011.1236] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To investigate the accumulation of intracellular advanced glycation end products (AGEs), a method was established for the simultaneous analysis of glycation products of cytosolic proteins, nuclear DNA, and mitochondrial DNA (mtDNA). Nuclear DNA, mtDNA, and cytosolic proteins were simultaneously isolated from one cell lysate by differential centrifugation and combined mechanical and chemical cell disruption methods. The major DNA-AGE N(2)-carboxyethyl-2'-deoxyguanosine (CEdG) was quantified in nuclear DNA and mtDNA by ELISA, whereas the protein-AGEs N(ɛ)-(carboxymethyl)lysine (CML) and N(ɛ)-(carboxyethyl)lysine (CEL) were determined by western blot. The method was used to analyze NIH3T3 fibroblasts. In untreated cells, CEdG levels of mtDNA (14.84 ± 3.07 pg CEdG/μg mtDNA) were significantly higher compared with nuclear DNA (4.40 ± 0.64 pg CEdG/μg DNA; p < 0.001). Then, fibroblasts were analyzed after 7 days of senescence-like growth arrest. In senescent fibroblasts, the CEdG content of nuclear DNA significantly increased by 25%. However, the CEdG level of mtDNA significantly decreased to 52%; in parallel, an increase in mitochondrial mass and mtDNA was observed. Senescence did not lead to general accumulation of protein-AGEs, but two protein bands at 32 and 34 kDa showed a significant increase in the CML/CEL modification rate (208%, p < 0.001; 196%, p = 0.0016) in senescent fibroblasts compared with control cells.
Collapse
Affiliation(s)
- Viola Breyer
- Department of Chemistry and Pharmacy, Food Chemistry, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | | |
Collapse
|
88
|
Benson RW, Norton MD, Lin I, Du Comb WS, Godoy VG. An active site aromatic triad in Escherichia coli DNA Pol IV coordinates cell survival and mutagenesis in different DNA damaging agents. PLoS One 2011; 6:e19944. [PMID: 21614131 PMCID: PMC3096655 DOI: 10.1371/journal.pone.0019944] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 04/07/2011] [Indexed: 12/16/2022] Open
Abstract
DinB (DNA Pol IV) is a translesion (TLS) DNA polymerase, which inserts a nucleotide opposite an otherwise replication-stalling N(2)-dG lesion in vitro, and confers resistance to nitrofurazone (NFZ), a compound that forms these lesions in vivo. DinB is also known to be part of the cellular response to alkylation DNA damage. Yet it is not known if DinB active site residues, in addition to aminoacids involved in DNA synthesis, are critical in alkylation lesion bypass. It is also unclear which active site aminoacids, if any, might modulate DinB's bypass fidelity of distinct lesions. Here we report that along with the classical catalytic residues, an active site "aromatic triad", namely residues F12, F13, and Y79, is critical for cell survival in the presence of the alkylating agent methyl methanesulfonate (MMS). Strains expressing dinB alleles with single point mutations in the aromatic triad survive poorly in MMS. Remarkably, these strains show fewer MMS- than NFZ-induced mutants, suggesting that the aromatic triad, in addition to its role in TLS, modulates DinB's accuracy in bypassing distinct lesions. The high bypass fidelity of prevalent alkylation lesions is evident even when the DinB active site performs error-prone NFZ-induced lesion bypass. The analyses carried out with the active site aromatic triad suggest that the DinB active site residues are poised to proficiently bypass distinctive DNA lesions, yet they are also malleable so that the accuracy of the bypass is lesion-dependent.
Collapse
Affiliation(s)
- Ryan W. Benson
- Department of Biology, Northeastern University, Boston, Massachusetts,
United States of America
| | - Matthew D. Norton
- Department of Biology, Northeastern University, Boston, Massachusetts,
United States of America
| | - Ida Lin
- Department of Biology, Northeastern University, Boston, Massachusetts,
United States of America
| | - William S. Du Comb
- Department of Biology, Northeastern University, Boston, Massachusetts,
United States of America
| | - Veronica G. Godoy
- Department of Biology, Northeastern University, Boston, Massachusetts,
United States of America
| |
Collapse
|
89
|
Yuan B, Wang J, Cao H, Sun R, Wang Y. High-throughput analysis of the mutagenic and cytotoxic properties of DNA lesions by next-generation sequencing. Nucleic Acids Res 2011; 39:5945-54. [PMID: 21470959 PMCID: PMC3152323 DOI: 10.1093/nar/gkr159] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Human cells are constantly exposed to environmental and endogenous agents which can induce damage to DNA. Understanding the implications of these DNA modifications in the etiology of human diseases requires the examination about how these DNA lesions block DNA replication and induce mutations in cells. All previously reported shuttle vector-based methods for investigating the cytotoxic and mutagenic properties of DNA lesions in cells have low-throughput, where plasmids containing individual lesions are transfected into cells one lesion at a time and the products from the replication of individual lesions are analyzed separately. The advent of next-generation sequencing (NGS) technology has facilitated investigators to design scientific approaches that were previously not technically feasible or affordable. In this study, we developed a new method employing NGS, together with shuttle vector technology, to have a multiplexed and quantitative assessment of how DNA lesions perturb the efficiency and accuracy of DNA replication in cells. By using this method, we examined the replication of four carboxymethylated DNA lesions and two oxidatively induced bulky DNA lesions including (5′S) diastereomers of 8,5′-cyclo-2′-deoxyguanosine (cyclo-dG) and 8,5′-cyclo-2′-deoxyadenosine (cyclo-dA) in five different strains of Escherichia coli cells. We further validated the results obtained from NGS using previously established methods. Taken together, the newly developed method provided a high-throughput and readily affordable method for assessing quantitatively how DNA lesions compromise the efficiency and fidelity of DNA replication in cells.
Collapse
Affiliation(s)
- Bifeng Yuan
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | | | | | | | | |
Collapse
|
90
|
Yuan B, You C, Andersen N, Jiang Y, Moriya M, O'Connor TR, Wang Y. The roles of DNA polymerases κ and ι in the error-free bypass of N2-carboxyalkyl-2'-deoxyguanosine lesions in mammalian cells. J Biol Chem 2011; 286:17503-11. [PMID: 21454642 DOI: 10.1074/jbc.m111.232835] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
To counteract the deleterious effects of DNA damage, cells are equipped with specialized polymerases to bypass DNA lesions. Previous biochemical studies revealed that DinB family DNA polymerases, including Escherichia coli DNA polymerase IV and human DNA polymerase κ, efficiently incorporate the correct nucleotide opposite some N(2)-modified 2'-deoxyguanosine derivatives. Herein, we used shuttle vector technology and demonstrated that deficiency in Polk or Poli in mouse embryonic fibroblast (MEF) cells resulted in elevated frequencies of G→T and G→A mutations at N(2)-(1-carboxyethyl)-2'-deoxyguanosine (N(2)-CEdG) and N(2)-carboxymethyl-2'-deoxyguanosine (N(2)-CMdG) sites. Steady-state kinetic measurements revealed that human DNA polymerase ι preferentially inserts the correct nucleotide, dCMP, opposite N(2)-CEdG lesions. In contrast, no mutation was found after the N(2)-CEdG- and N(2)-CMdG-bearing plasmids were replicated in POLH-deficient human cells or Rev3-deficient MEF cells. Together, our results revealed that, in mammalian cells, both polymerases κ and ι are necessary for the error-free bypass of N(2)-CEdG and N(2)-CMdG. However, in the absence of polymerase κ or ι, other translesion synthesis polymerase(s) could incorporate nucleotide(s) opposite these lesions but would do so inaccurately.
Collapse
Affiliation(s)
- Bifeng Yuan
- From the Department of Chemistry, University of California, Riverside, California 92521, USA
| | | | | | | | | | | | | |
Collapse
|
91
|
DNA damage induced by endogenous aldehydes: current state of knowledge. Mutat Res 2011; 711:13-27. [PMID: 21419140 DOI: 10.1016/j.mrfmmm.2011.03.006] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/01/2011] [Accepted: 03/03/2011] [Indexed: 12/16/2022]
Abstract
DNA damage plays a major role in various pathophysiological conditions including carcinogenesis, aging, inflammation, diabetes and neurodegenerative diseases. Oxidative stress and cell processes such as lipid peroxidation and glycation induce the formation of highly reactive endogenous aldehydes that react directly with DNA, form aldehyde-derived DNA adducts and lead to DNA damage. In occasion of persistent conditions that influence the formation and accumulation of aldehyde-derived DNA adducts the resulting unrepaired DNA damage causes deregulation of cell homeostasis and thus significantly contributes to disease phenotype. Some of the most highly reactive aldehydes produced endogenously are 4-hydroxy-2-nonenal, malondialdehyde, acrolein, crotonaldehyde and methylglyoxal. The mutagenic and carcinogenic effects associated with the elevated levels of these reactive aldehydes, especially, under conditions of stress, are attributed to their capability of causing directly modification of DNA bases or yielding promutagenic exocyclic adducts. In this review, we discuss the current knowledge on DNA damage induced by endogenously produced reactive aldehydes in relation to the pathophysiology of human diseases.
Collapse
|
92
|
Ishii Y, Suzuki Y, Hibi D, Jin M, Fukuhara K, Umemura T, Nishikawa A. Detection and Quantification of Specific DNA Adducts by Liquid Chromatography−Tandem Mass Spectrometry in the Livers of Rats Given Estragole at the Carcinogenic Dose. Chem Res Toxicol 2011; 24:532-41. [DOI: 10.1021/tx100410y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Yuji Ishii
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Yuta Suzuki
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Daisuke Hibi
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Meilan Jin
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Kiyoshi Fukuhara
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Takashi Umemura
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Akiyoshi Nishikawa
- Division of Pathology and ‡Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| |
Collapse
|
93
|
Gutierrez A, Elez M, Clermont O, Denamur E, Matic I. Escherichia coli YafP protein modulates DNA damaging property of the nitroaromatic compounds. Nucleic Acids Res 2011; 39:4192-201. [PMID: 21300638 PMCID: PMC3105422 DOI: 10.1093/nar/gkr050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Escherichia coli SOS functions constitute a multifaceted response to DNA damage. We undertook to study the role of yafP, a SOS gene with unknown function. yafP is part of an operon also containing the dinB gene coding for DNA Polymerase IV (PolIV). Our phylogenetic analysis showed that the gene content of this operon is variable but that the dinB and the yafP genes are conserved in the majority of E. coli natural isolates. Therefore, we studied if these proteins are functionally linked. Using a murine septicaemia model, we showed that YafP activity reduced the bacterial fitness in the absence of PolIV. Similarly, YafP increased cytotoxicity of two DNA damaging nitroaromatic compounds, 4-nitroquinoline-1-oxide (NQO) and nitrofurazone, in the absence of PolIV. The fact that PolIV counterbalances YafP-induced cytotoxicity could explain why these two genes are transcriptionally linked. We also studied the involvement of YafP in genotoxic-stress induced mutagenesis and found that PolIV and YafP reduced NQO-induced mutagenicity. The YafP antimutator activity was independent of the PolIV activity. Given that YafP was annotated as a putative acetyltransferase, it could be that YafP participates in the metabolic transformation of genotoxic compounds, hence modulating the balance between their mutagenicity and cytotoxicity.
Collapse
Affiliation(s)
- Arnaud Gutierrez
- Faculté de Médecine Paris Descartes, Inserm U1001, Université Paris Descartes, Paris, France
| | | | | | | | | |
Collapse
|
94
|
Yuan B, O’Connor TR, Wang Y. 6-Thioguanine and S⁶-methylthioguanine are mutagenic in human cells. ACS Chem Biol 2010; 5:1021-7. [PMID: 20806951 DOI: 10.1021/cb100214b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thiopurines are effective immunosuppressants and anticancer agents. However, the long-term use of thiopurines was found to be associated with a significantly increased risk of various types of cancer. To date, the specific mechanism(s) underlying the carcinogenicity associated with thiopurine treatment remain(s) unclear. Herein, we constructed duplex pTGFP-Hha10 shuttle vectors carrying a 6-thioguanine ((S)G) or S⁶-methylthioguanine (S⁶mG) at a unique site and allowed the vectors to propagate in three different human cell lines. Analysis of the replication products revealed that although neither thionucleoside blocked considerably DNA replication in any of the human cell lines, both (S)G and S⁶mG were mutagenic, resulting in G→A mutation at frequencies of ~8% and ~39%, respectively. Consistent with what was found from our previous study in E. coli cells, our data demonstrated that the mutagenic properties of (S)G and S⁶mG provided significant evidence for mutation induction as a potential carcinogenic mechanism associated with chronic thiopurine intervention.
Collapse
Affiliation(s)
- Bifeng Yuan
- Department of Chemistry, University of California, Riverside, California 92521
| | - Timothy R. O’Connor
- Biology Division, Beckman Research Institute, City of Hope National Medical Center, Duarte, California 91010
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521
| |
Collapse
|
95
|
Sassa A, Niimi N, Fujimoto H, Katafuchi A, Grúz P, Yasui M, Gupta RC, Johnson F, Ohta T, Nohmi T. Phenylalanine 171 is a molecular brake for translesion synthesis across benzo[a]pyrene-guanine adducts by human DNA polymerase kappa. Mutat Res 2010; 718:10-7. [PMID: 21078407 DOI: 10.1016/j.mrgentox.2010.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/05/2010] [Accepted: 11/05/2010] [Indexed: 10/18/2022]
Abstract
Human cells possess multiple specialized DNA polymerases (Pols) that bypass a variety of DNA lesions which otherwise would block chromosome replication. Human polymerase kappa (Pol κ) bypasses benzo[a]pyrene diolepoxide-N(2)-deoxyguanine (BPDE-N(2)-dG) DNA adducts in an almost error-free manner. To better understand the relationship between the structural features in the active site and lesion bypass by Pol κ, we mutated codons corresponding to amino acids appearing close to the adducts in the active site, and compared bypass efficiencies. Remarkably, the substitution of alanine for phenylalanine 171 (F171), an amino acid conserved between Pol κ and its bacterial counterpart Escherichia coli DinB, enhanced the efficiencies of dCMP incorporation opposite (-)- and (+)-trans-anti-BPDE-N(2)-dG 18-fold. This substitution affected neither the fidelity of TLS nor the efficiency of dCMP incorporation opposite normal guanine. This amino acid change also enhanced the binding affinity of Pol κ to template/primer DNA containing (-)-trans-anti-BPDE-N(2)-dG. These results suggest that F171 functions as a molecular brake for TLS across BPDE-N(2)-dG by Pol κ and that the F171A derivative of Pol κ bypasses these DNA lesions more actively than does the wild-type enzyme.
Collapse
MESH Headings
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/analogs & derivatives
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/chemistry
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/metabolism
- Amino Acid Substitution
- Base Sequence
- Benzo(a)pyrene/chemistry
- Benzo(a)pyrene/metabolism
- Catalytic Domain/genetics
- DNA Adducts/chemistry
- DNA Adducts/metabolism
- DNA Damage
- DNA Primers/genetics
- DNA Repair
- DNA-Directed DNA Polymerase/chemistry
- DNA-Directed DNA Polymerase/genetics
- DNA-Directed DNA Polymerase/metabolism
- Deoxyguanosine/analogs & derivatives
- Deoxyguanosine/chemistry
- Deoxyguanosine/metabolism
- Escherichia coli Proteins/chemistry
- Escherichia coli Proteins/genetics
- Escherichia coli Proteins/metabolism
- Humans
- In Vitro Techniques
- Kinetics
- Models, Molecular
- Mutagenesis, Site-Directed
- Phenylalanine/chemistry
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Substrate Specificity
Collapse
Affiliation(s)
- Akira Sassa
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
96
|
The DNA polymerase activity of Saccharomyces cerevisiae Rev1 is biologically significant. Genetics 2010; 187:21-35. [PMID: 20980236 DOI: 10.1534/genetics.110.124172] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A cell's ability to tolerate DNA damage is directly connected to the human development of diseases and cancer. To better understand the processes underlying mutagenesis, we studied the cell's reliance on the potentially error-prone translesion synthesis (TLS), and an error-free, template-switching pathway in Saccharomyces cerevisiae. The primary proteins mediating S. cerevisiae TLS are three DNA polymerases (Pols): Rev1, Pol ζ (Rev3/7), and Pol η (Rad30), all with human homologs. Rev1's noncatalytic role in recruiting other DNA polymerases is known to be important for TLS. However, the biological significance of Rev1's unusual conserved DNA polymerase activity, which inserts dC, is much less well understood. Here, we demonstrate that inactivating Rev1's DNA polymerase function sensitizes cells to both chronic and acute exposure to 4-nitroquinoline-1-oxide (4-NQO) but not to UV or cisplatin. Full Rev1-dependent resistance to 4-NQO, however, also requires the additional Rev1 functions. When error-free tolerance is disrupted through deletion of MMS2, Rev1's catalytic activity is more vital for 4-NQO resistance, possibly explaining why the biological significance of Rev1's catalytic activity has been elusive. In the presence or absence of Mms2-dependent error-free tolerance, the catalytic dead strain of Rev1 exhibits a lower 4-NQO-induced mutation frequency than wild type. Furthermore, Pol ζ, but not Pol η, also contributes to 4-NQO resistance. These results show that Rev1's catalytic activity is important in vivo when the cell has to cope with specific DNA lesions, such as N(2)-dG.
Collapse
|
97
|
Hori M, Yonekura SI, Nohmi T, Gruz P, Sugiyama H, Yonei S, Zhang-Akiyama QM. Error-Prone Translesion DNA Synthesis by Escherichia coli DNA Polymerase IV (DinB) on Templates Containing 1,2-dihydro-2-oxoadenine. J Nucleic Acids 2010; 2010:807579. [PMID: 20976264 PMCID: PMC2952919 DOI: 10.4061/2010/807579] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 07/14/2010] [Accepted: 08/05/2010] [Indexed: 12/13/2022] Open
Abstract
Escherichia coli DNA polymerase IV (Pol IV) is involved in bypass replication of damaged bases in DNA. Reactive oxygen species (ROS) are generated continuously during normal metabolism and as a result of exogenous stress such as ionizing radiation. ROS induce various kinds of base damage in DNA. It is important to examine whether Pol IV is able to bypass oxidatively damaged bases. In this study, recombinant Pol IV was incubated with oligonucleotides containing thymine glycol (dTg), 5-formyluracil (5-fodU), 5-hydroxymethyluracil (5-hmdU), 7,8-dihydro-8-oxoguanine (8-oxodG) and 1,2-dihydro-2-oxoadenine (2-oxodA). Primer extension assays revealed that Pol IV preferred to insert dATP opposite 5-fodU and 5-hmdU, while it inefficiently inserted nucleotides opposite dTg. Pol IV inserted dCTP and dATP opposite 8-oxodG, while the ability was low. It inserted dCTP more effectively than dTTP opposite 2-oxodA. Pol IV's ability to bypass these lesions decreased in the order: 2-oxodA > 5-fodU~5-hmdU > 8-oxodG > dTg. The fact that Pol IV preferred to insert dCTP opposite 2-oxodA suggests the mutagenic potential of 2-oxodA leading to A:T→G:C transitions. Hydrogen peroxide caused an ~2-fold increase in A:T→G:C mutations in E. coli, while the increase was significantly greater in E. coli overexpressing Pol IV. These results indicate that Pol IV may be involved in ROS-enhanced A:T→G:C mutations.
Collapse
Affiliation(s)
- Masaki Hori
- Laboratory of Stress Response Biology, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | | | | | | | | | | | | |
Collapse
|
98
|
Chandani S, Jacobs C, Loechler EL. Architecture of y-family DNA polymerases relevant to translesion DNA synthesis as revealed in structural and molecular modeling studies. J Nucleic Acids 2010; 2010. [PMID: 20936174 PMCID: PMC2945684 DOI: 10.4061/2010/784081] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 07/26/2010] [Indexed: 12/22/2022] Open
Abstract
DNA adducts, which block replicative DNA polymerases (DNAPs), are often bypassed by lesion-bypass DNAPs, which are mostly in the Y-Family. Y-Family DNAPs can do non-mutagenic or mutagenic dNTP insertion, and understanding this difference is important, because mutations transform normal into tumorigenic cells. Y-Family DNAP architecture that dictates mechanism, as revealed in structural and modeling studies, is considered. Steps from adduct blockage of replicative DNAPs, to bypass by a lesion-bypass DNAP, to resumption of synthesis by a replicative DNAP are described. Catalytic steps and protein conformational changes are considered. One adduct is analyzed in greater detail: the major benzo[a]pyrene adduct (B[a]P-N2-dG), which is bypassed non-mutagenically (dCTP insertion) by Y-family DNAPs in the IV/κ-class and mutagenically (dATP insertion) by V/η-class Y-Family DNAPs. Important architectural differences between IV/κ-class versus V/η-class DNAPs are discussed, including insights gained by analyzing ~400 sequences each for bacterial DNAPs IV and V, along with sequences from eukaryotic DNAPs kappa, eta and iota. The little finger domains of Y-Family DNAPs do not show sequence conservation; however, their structures are remarkably similar due to the presence of a core of hydrophobic amino acids, whose exact identity is less important than the hydrophobic amino acid spacing.
Collapse
Affiliation(s)
- Sushil Chandani
- Biology Department, Boston University, Boston, MA 02215, USA
| | | | | |
Collapse
|
99
|
Roles for the transcription elongation factor NusA in both DNA repair and damage tolerance pathways in Escherichia coli. Proc Natl Acad Sci U S A 2010; 107:15517-22. [PMID: 20696893 DOI: 10.1073/pnas.1005203107] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report observations suggesting that the transcription elongation factor NusA promotes a previously unrecognized class of transcription-coupled repair (TCR) in addition to its previously proposed role in recruiting translesion synthesis (TLS) DNA polymerases to gaps encountered during transcription. Earlier, we reported that NusA physically and genetically interacts with the TLS DNA polymerase DinB (DNA pol IV). We find that Escherichia coli nusA11(ts) mutant strains, at the permissive temperature, are highly sensitive to nitrofurazone (NFZ) and 4-nitroquinolone-1-oxide but not to UV radiation. Gene expression profiling suggests that this sensitivity is unlikely to be due to an indirect effect on gene expression affecting a known DNA repair or damage tolerance pathway. We demonstrate that an N(2)-furfuryl-dG (N(2)-f-dG) lesion, a structural analog of the principal lesion generated by NFZ, blocks transcription by E. coli RNA polymerase (RNAP) when present in the transcribed strand, but not when present in the nontranscribed strand. Our genetic analysis suggests that NusA participates in a nucleotide excision repair (NER)-dependent process to promote NFZ resistance. We provide evidence that transcription plays a role in the repair of NFZ-induced lesions through the isolation of RNAP mutants that display altered ability to survive NFZ exposure. We propose that NusA participates in an alternative class of TCR involved in the identification and removal of a class of lesion, such as the N(2)-f-dG lesion, which are accurately and efficiently bypassed by DinB in addition to recruiting DinB for TLS at gaps encountered by RNAP.
Collapse
|
100
|
Thornalley PJ, Waris S, Fleming T, Santarius T, Larkin SJ, Winklhofer-Roob BM, Stratton MR, Rabbani N. Imidazopurinones are markers of physiological genomic damage linked to DNA instability and glyoxalase 1-associated tumour multidrug resistance. Nucleic Acids Res 2010; 38:5432-42. [PMID: 20435681 PMCID: PMC2938218 DOI: 10.1093/nar/gkq306] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Glyoxal and methylglyoxal are reactive dicarbonyl metabolites formed and metabolized in physiological systems. Increased exposure to these dicarbonyls is linked to mutagenesis and cytotoxicity and enhanced dicarbonyl metabolism by overexpression of glyoxalase 1 is linked to tumour multidrug resistance in cancer chemotherapy. We report herein that glycation of DNA by glyoxal and methylglyoxal produces a quantitatively important class of nucleotide adduct in physiological systems—imidazopurinones. The adduct derived from methylglyoxal-3-(2′-deoxyribosyl)-6,7-dihydro-6,7-dihydroxy-6/7-methylimidazo-[2,3-b]purine-9(8)one isomers—was the major quantitative adduct detected in mononuclear leukocytes in vivo and tumour cell lines in vitro. It was linked to frequency of DNA strand breaks and increased markedly during apoptosis induced by a cell permeable glyoxalase 1 inhibitor. Unexpectedly, the DNA content of methylglyoxal-derived imidazopurinone and oxidative marker 7,8-dihydro-8-oxo-2′-deoxyguanosine were increased moderately in glyoxalase 1-linked multidrug resistant tumour cell lines. Together these findings suggest that imidazopurinones are a major type of endogenous DNA damage and glyoxalase 1 overexpression in tumour cells strives to counter increased imidazopurinone formation in tumour cells likely linked to their high glycolytic activity.
Collapse
Affiliation(s)
- Paul J Thornalley
- Warwick Medical School, Clinical Sciences Research Institute, University of Warwick, University Hospital, Coventry CV2 2DX, UK.
| | | | | | | | | | | | | | | |
Collapse
|