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Thompson MK, Sobol RW, Prakash A. Exploiting DNA Endonucleases to Advance Mechanisms of DNA Repair. BIOLOGY 2021; 10:530. [PMID: 34198612 PMCID: PMC8232306 DOI: 10.3390/biology10060530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/17/2022]
Abstract
The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.
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Affiliation(s)
- Marlo K. Thompson
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - Aishwarya Prakash
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
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Leitner-Dagan Y, Sevilya Z, Pinchev M, Kremer R, Elinger D, Rennert HS, Schechtman E, Freedman L, Rennert G, Livneh Z, Paz-Elizur T. Enzymatic MPG DNA repair assays for two different oxidative DNA lesions reveal associations with increased lung cancer risk. Carcinogenesis 2014; 35:2763-70. [PMID: 25355292 DOI: 10.1093/carcin/bgu214] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
DNA repair is a major mechanism for minimizing mutations and reducing cancer risk. Here, we present the development of reproducible and specific enzymatic assays for methylpurine DNA glycosylase (MPG) repairing the oxidative lesions 1,N6-ethenoadenine (εA) and hypoxanthine (Hx) in peripheral blood mononuclear cells protein extracts. Association of these DNA repair activities with lung cancer was determined using conditional logistic regression with specimens from a population-based case-control study with 96 lung cancer cases and 96 matched control subjects. The mean MPG-εA in case patients was 15.8 units/μg protein (95% CI 15.3-16.3), significantly higher than in control subjects-15.1 (14.6-15.5), *P = 0.011. The adjusted odds ratio for lung cancer associated with a one SD increase in MPG-εA activity (2.48 units) was significantly bigger than 1 (OR = 1.6, 95% CI = 1.1-2.4; *P = 0.013). When activity of OGG1, a different DNA repair enzyme for oxidative damage, was included in the model, the estimated odds ratio/SD for a combined MPG-εA-OGG1 score was 2.6 (95% CI 1.6-4.2) *P = 0.0001, higher than the odds ratio for each single assay. The MPG enzyme activity assays described provide robust functional risk biomarkers, with increased MPG-εA activity being associated with increased lung cancer risk, similar to the behavior of MPG-Hx. This underscores the notion that imbalances in DNA repair, including high DNA repair, usually perceived as beneficial, can cause cancer risk. Such DNA repair risk biomarkers may be useful for risk assessment of lung cancer and perhaps other cancer types, and for early detection techniques such as low-dose CT.
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Affiliation(s)
- Yael Leitner-Dagan
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Ziv Sevilya
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Mila Pinchev
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Ran Kremer
- Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel
| | - Dalia Elinger
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Hedy S Rennert
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Edna Schechtman
- Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and
| | - Laurence Freedman
- Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Gad Rennert
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Zvi Livneh
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Tamar Paz-Elizur
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
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Meira LB, Calvo JA, Shah D, Klapacz J, Moroski-Erkul CA, Bronson RT, Samson LD. Repair of endogenous DNA base lesions modulate lifespan in mice. DNA Repair (Amst) 2014; 21:78-86. [PMID: 24994062 PMCID: PMC4125484 DOI: 10.1016/j.dnarep.2014.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/30/2014] [Accepted: 05/20/2014] [Indexed: 12/21/2022]
Abstract
The accumulation of DNA damage is thought to contribute to the physiological decay associated with the aging process. Here, we report the results of a large-scale study examining longevity in various mouse models defective in the repair of DNA alkylation damage, or defective in the DNA damage response. We find that the repair of spontaneous DNA damage by alkyladenine DNA glycosylase (Aag/Mpg)-initiated base excision repair and O(6)-methylguanine DNA methyltransferase (Mgmt)-mediated direct reversal contributes to maximum life span in the laboratory mouse. We also uncovered important genetic interactions between Aag, which excises a wide variety of damaged DNA bases, and the DNA damage sensor and signaling protein, Atm. We show that Atm plays a role in mediating survival in the face of both spontaneous and induced DNA damage, and that Aag deficiency not only promotes overall survival, but also alters the tumor spectrum in Atm(-/-) mice. Further, the reversal of spontaneous alkylation damage by Mgmt interacts with the DNA mismatch repair pathway to modulate survival and tumor spectrum. Since these aging studies were performed without treatment with DNA damaging agents, our results indicate that the DNA damage that is generated endogenously accumulates with age, and that DNA alkylation repair proteins play a role in influencing longevity.
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Affiliation(s)
- Lisiane B Meira
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Jennifer A Calvo
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Dharini Shah
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Joanna Klapacz
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Catherine A Moroski-Erkul
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Roderick T Bronson
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Rodent Histopathology Core, Harvard Medical School, 126 Goldenson Building, Boston, MA 02115, United States
| | - Leona D Samson
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Biology Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Rodent Histopathology Core, Harvard Medical School, 126 Goldenson Building, Boston, MA 02115, United States.
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Yan S, Sorrell M, Berman Z. Functional interplay between ATM/ATR-mediated DNA damage response and DNA repair pathways in oxidative stress. Cell Mol Life Sci 2014; 71:3951-67. [PMID: 24947324 DOI: 10.1007/s00018-014-1666-4] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 02/07/2023]
Abstract
To maintain genome stability, cells have evolved various DNA repair pathways to deal with oxidative DNA damage. DNA damage response (DDR) pathways, including ATM-Chk2 and ATR-Chk1 checkpoints, are also activated in oxidative stress to coordinate DNA repair, cell cycle progression, transcription, apoptosis, and senescence. Several studies demonstrate that DDR pathways can regulate DNA repair pathways. On the other hand, accumulating evidence suggests that DNA repair pathways may modulate DDR pathway activation as well. In this review, we summarize our current understanding of how various DNA repair and DDR pathways are activated in response to oxidative DNA damage primarily from studies in eukaryotes. In particular, we analyze the functional interplay between DNA repair and DDR pathways in oxidative stress. A better understanding of cellular response to oxidative stress may provide novel avenues of treating human diseases, such as cancer and neurodegenerative disorders.
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Affiliation(s)
- Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA,
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Cannan WJ, Tsang BP, Wallace SS, Pederson DS. Nucleosomes suppress the formation of double-strand DNA breaks during attempted base excision repair of clustered oxidative damages. J Biol Chem 2014; 289:19881-93. [PMID: 24891506 DOI: 10.1074/jbc.m114.571588] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure to ionizing radiation can produce multiple, clustered oxidative lesions in DNA. The near simultaneous excision of nearby lesions in opposing DNA strands by the base excision repair (BER) enzymes can produce double-strand DNA breaks (DSBs). This attempted BER accounts for many of the potentially lethal or mutagenic DSBs that occur in vivo. To assess the impact of nucleosomes on the frequency and pattern of BER-dependent DSB formation, we incubated nucleosomes containing oxidative damages in opposing DNA strands with selected DNA glycosylases and human apurinic/apyrimidinic endonuclease 1. Overall, nucleosomes substantially suppressed DSB formation. However, the degree of suppression varied as a function of (i) the lesion type and DNA glycosylase tested, (ii) local sequence context and the stagger between opposing strand lesions, (iii) the helical orientation of oxidative lesions relative to the underlying histone octamer, and (iv) the distance between the lesion cluster and the nucleosome edge. In some instances the binding of a BER factor to one nucleosomal lesion appeared to facilitate binding to the opposing strand lesion. DSB formation did not invariably lead to nucleosome dissolution, and in some cases, free DNA ends resulting from DSB formation remained associated with the histone octamer. These observations explain how specific structural and dynamic properties of nucleosomes contribute to the suppression of BER-generated DSBs. These studies also suggest that most BER-generated DSBs will occur in linker DNA and in genomic regions associated with elevated rates of nucleosome turnover or remodeling.
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Affiliation(s)
- Wendy J Cannan
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Betty P Tsang
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Susan S Wallace
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - David S Pederson
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
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Structures of the Leishmania infantum polymerase beta. DNA Repair (Amst) 2014; 18:1-9. [PMID: 24666693 DOI: 10.1016/j.dnarep.2014.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/28/2014] [Accepted: 03/01/2014] [Indexed: 11/21/2022]
Abstract
Protozoans of the genus Leishmania, the pathogenic agent causing leishmaniasis, encode the family X DNA polymerase Li Pol β. Here, we report the first crystal structures of Li Pol β. Our pre- and post-catalytic structures show that the polymerase adopts the common family X DNA polymerase fold. However, in contrast to other family X DNA polymerases, the dNTP-induced conformational changes in Li Pol β are much more subtle. Moreover, pre- and post-catalytic structures reveal that Li Pol β interacts with the template strand through a nonconserved, variable region known as loop3. Li Pol β Δloop3 mutants display a higher catalytic rate, catalytic efficiency and overall error rates with respect to WT Li Pol β. These results further demonstrate the subtle structural variability that exists within this family of enzymes and provides insight into how this variability underlies the substantial functional differences among their members.
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Sevilya Z, Leitner-Dagan Y, Pinchev M, Kremer R, Elinger D, Rennert HS, Schechtman E, Freedman LS, Rennert G, Paz-Elizur T, Livneh Z. Low integrated DNA repair score and lung cancer risk. Cancer Prev Res (Phila) 2013; 7:398-406. [PMID: 24356339 DOI: 10.1158/1940-6207.capr-13-0318] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DNA repair is a prime mechanism for preventing DNA damage, mutation, and cancers. Adopting a functional approach, we examined the association with lung cancer risk of an integrated DNA repair score, measured by a panel of three enzymatic DNA repair activities in peripheral blood mononuclear cells. The panel included assays for AP endonuclease 1 (APE1), 8-oxoguanine DNA glycosylase (OGG1), and methylpurine DNA glycosylase (MPG), all of which repair oxidative DNA damage as part of the base excision repair pathways. A blinded population-based case-control study was conducted with 96 patients with lung cancer and 96 control subjects matched by gender, age (±1 year), place of residence, and ethnic group (Jews/non-Jews). The three DNA repair activities were measured, and an integrated DNA repair OMA (OGG1, MPG, and APE1) score was calculated for each individual. Conditional logistic regression analysis revealed that individuals in the lowest tertile of the integrated DNA repair OMA score had an increased risk of lung cancer compared with the highest tertile, with OR = 9.7; 95% confidence interval (CI), 3.1-29.8; P < 0.001, or OR = 5.6; 95% CI, 2.1-15.1; P < 0.001 after cross-validation. These results suggest that pending validation, this DNA repair panel of risk factors may be useful for lung cancer risk assessment, assisting prevention and referral to early detection by technologies such as low-dose computed tomography scanning.
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Affiliation(s)
- Ziv Sevilya
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel. and
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APE2 is required for ATR-Chk1 checkpoint activation in response to oxidative stress. Proc Natl Acad Sci U S A 2013; 110:10592-7. [PMID: 23754435 DOI: 10.1073/pnas.1301445110] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The base excision repair pathway is largely responsible for the repair of oxidative stress-induced DNA damage. However, it remains unclear how the DNA damage checkpoint is activated by oxidative stress at the molecular level. Here, we provide evidence showing that hydrogen peroxide (H2O2) triggers checkpoint kinase 1 (Chk1) phosphorylation in an ATR [ataxia-telangiectasia mutated (ATM) and Rad3-related]-dependent but ATM-independent manner in Xenopus egg extracts. A base excision repair protein, Apurinic/apyrimidinic (AP) endonuclease 2 (APE2, APN2, or APEX2), is required for the generation of replication protein A (RPA)-bound single-stranded DNA, the recruitment of a checkpoint protein complex [ATR, ATR-interacting protein (ATRIP), and Rad9] to damage sites, and H2O2-induced Chk1 phosphorylation. A conserved proliferating cell nuclear antigen interaction protein box of APE2 is important for the recruitment of APE2 to H2O2-damaged chromatin. APE2 3'-phosphodiesterase and 3'-5' exonuclease activity is essential for single-stranded DNA generation in the 3'-5' direction from single-stranded breaks, referred to as single-stranded break end resection. In addition, APE2 associates with Chk1, and a serine residue (S86) in the Chk1-binding motif of APE2 is essential for Chk1 phosphorylation, indicating a Claspin-like but distinct role for APE2 in ATR-Chk1 signaling. Our data indicate that APE2 plays a vital and previously unexpected role in ATR-Chk1 checkpoint signaling in response to oxidative stress. Thus, our findings shed light on a distinct mechanism of how an ATR-Chk1-dependent DNA damage checkpoint is mediated by APE2 in the oxidative stress response.
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Odell ID, Wallace SS, Pederson DS. Rules of engagement for base excision repair in chromatin. J Cell Physiol 2013; 228:258-66. [PMID: 22718094 DOI: 10.1002/jcp.24134] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Most of the DNA in eukaryotes is packaged in tandemly arrayed nucleosomes that, together with numerous DNA- and nucleosome-associated enzymes and regulatory factors, make up chromatin. Chromatin modifying and remodeling agents help regulate access to selected DNA segments in chromatin, thereby facilitating transcription and DNA replication and repair. Studies of nucleotide excision repair (NER), single strand break repair (SSBR), and the homology-directed repair (HDR), and non-homologous end-joining (NHEJ) double strand break repair pathways have led to an "access-repair-restore" paradigm, in which chromatin in the vicinity of damaged DNA is disrupted, thereby enabling efficient repair and the subsequent repackaging of DNA into nucleosomes. When damage is extensive, these repair processes are accompanied by cell cycle checkpoint activation, which provides cells with sufficient time to either complete the repair or initiate apoptosis. It is not clear, however, if base excision repair (BER) of the ~20,000 or more oxidative DNA damages that occur daily in each nucleated human cell can be viewed through this same lens. Until recently, we did not know if BER requires or is accompanied by nucleosome disruption, and it is not yet clear that anything short of overwhelming oxidative damage (resulting in the shunting of DNA substrates into other repair pathways) results in checkpoint activation. This review highlights studies of how oxidatively damaged DNA in nucleosomes is discovered and repaired, and offers a working model of events associated with BER in chromatin that we hope will have heuristic value.
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Affiliation(s)
- Ian D Odell
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA
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10
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Leitner-Dagan Y, Sevilya Z, Pinchev M, Kramer R, Elinger D, Roisman LC, Rennert HS, Schechtman E, Freedman L, Rennert G, Livneh Z, Paz-Elizur T. N-methylpurine DNA glycosylase and OGG1 DNA repair activities: opposite associations with lung cancer risk. J Natl Cancer Inst 2012; 104:1765-9. [PMID: 23104324 PMCID: PMC3502197 DOI: 10.1093/jnci/djs445] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Only a minority of smokers develop lung cancer, possibly due to genetic predisposition, including DNA repair deficiencies. To examine whether inter-individual variations in DNA repair activity of N-methylpurine DNA glycosylase (MPG) are associated with lung cancer, we conducted a blinded, population-based, case–control study with 100 lung cancer case patients and 100 matched control subjects and analyzed the data with conditional logistic regression. All statistical tests were two-sided. MPG enzyme activity in peripheral blood mononuclear cells from case patients was higher than in control subjects, results opposite that of 8-oxoguanine DNA glycosylase (OGG1) DNA repair enzyme activity. For lung cancer associated with one standard deviation increase in MPG activity, the adjusted odds ratio was 1.8 (95% confidence interval [CI] = 1.2 to 2.6; P = .006). A combined MPG and OGG1 activities score was more strongly associated with lung cancer risk than either activity alone, with an odds ratio of 2.3 (95% CI = 1.4 to 3.6; P < .001). These results form a basis for a future panel of risk biomarkers for lung cancer risk assessment and prevention.
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Affiliation(s)
- Yael Leitner-Dagan
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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11
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Lee SH, Wang S, Kool ET. Templated chemistry for monitoring damage and repair directly in duplex DNA. Chem Commun (Camb) 2012; 48:8069-71. [PMID: 22782065 DOI: 10.1039/c2cc34060g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report the fluorogenic detection of the product of base excision repair (an abasic site) in a specific sequence of duplex DNA. This is achieved by DNA-templated chemistry, employing triple helix-forming probes that contain unnatural nucleobases designed to selectively recognize the site of a missing base. Light-up signals of up to 36-fold were documented, and probes could be used to monitor enzymatic removal of a damaged base.
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Affiliation(s)
- Seoung Ho Lee
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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12
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Ruchko MV, Gorodnya OM, Zuleta A, Pastukh VM, Gillespie MN. The DNA glycosylase Ogg1 defends against oxidant-induced mtDNA damage and apoptosis in pulmonary artery endothelial cells. Free Radic Biol Med 2011; 50:1107-13. [PMID: 20969951 PMCID: PMC3033972 DOI: 10.1016/j.freeradbiomed.2010.10.692] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 09/17/2010] [Accepted: 10/09/2010] [Indexed: 10/18/2022]
Abstract
Emerging evidence suggests that mitochondrial (mt) DNA damage may be a trigger for apoptosis in oxidant-challenged pulmonary artery endothelial cells (PAECs). Understanding the rate-limiting determinants of mtDNA repair may point to new targets for intervention in acute lung injury. The base excision repair (BER) pathway is the only pathway for oxidative damage repair in mtDNA. One of the key BER enzymes is Ogg1, which excises the base oxidation product 8-oxoguanine. Previously we demonstrated that overexpression of mitochondrially targeted Ogg1 in PAECs attenuated apoptosis induced by xanthine oxidase (XO) treatment. To test the idea that Ogg1 is a potentially rate-limiting BER determinant protecting cells from oxidant-mediated death, PAECs transfected with siRNA to Ogg1 were challenged with XO and the extent of mitochondrial and nuclear DNA damage was determined along with indices of apoptosis. Transfected cells demonstrated significantly reduced Ogg1 activity, which was accompanied by delayed repair of XO-induced mtDNA damage and linked to increased XO-mediated apoptosis. The nuclear genome was undamaged by XO in either control PAECs or cells depleted of Ogg1. These observations suggest that Ogg1 plays a critical and possibly rate-limiting role in defending PAECs from oxidant-induced apoptosis by limiting the persistence of oxidative damage in the mitochondrial genome.
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Affiliation(s)
| | | | | | | | - Mark N. Gillespie
- Correspondence: Mark N. Gillespie, Ph.D., Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, Telephone: (251) 460-6497, Fax: (251) 460-6798,
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Preston BD, Albertson TM, Herr AJ. DNA replication fidelity and cancer. Semin Cancer Biol 2010; 20:281-93. [PMID: 20951805 PMCID: PMC2993855 DOI: 10.1016/j.semcancer.2010.10.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Accepted: 10/07/2010] [Indexed: 12/14/2022]
Abstract
Cancer is fueled by mutations and driven by adaptive selection. Normal cells avoid deleterious mutations by replicating their genomes with extraordinary accuracy. Here we review the pathways governing DNA replication fidelity and discuss evidence implicating replication errors (point mutation instability or PIN) in carcinogenesis.
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Affiliation(s)
- Bradley D Preston
- Department of Pathology, University of Washington, Seattle, WA 98195, USA.
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14
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Wirtz S, Nagel G, Eshkind L, Neurath MF, Samson LD, Kaina B. Both base excision repair and O6-methylguanine-DNA methyltransferase protect against methylation-induced colon carcinogenesis. Carcinogenesis 2010; 31:2111-7. [PMID: 20732909 PMCID: PMC2994278 DOI: 10.1093/carcin/bgq174] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Methylating agents are widely distributed environmental carcinogens. Moreover, they are being used in cancer chemotherapy. The primary target of methylating agents is DNA, and therefore, DNA repair is the first-line barrier in defense against their toxic and carcinogenic effects. Methylating agents induce in the DNA O(6)-methylguanine (O(6)MeG) and methylations of the ring nitrogens of purines. The lesions are repaired by O(6)-methylguanine-DNA methyltransferase (Mgmt) and by enzymes of the base excision repair (BER) pathway, respectively. Whereas O(6)MeG is well established as a pre-carcinogenic lesion, little is known about the carcinogenic potency of base N-alkylation products such as N3-methyladenine and N3-methylguanine. To determine their role in cancer formation and the role of BER in cancer protection, we checked the response of mice with a targeted gene disruption of Mgmt or N-alkylpurine-DNA glycosylase (Aag) or both Mgmt and Aag, to azoxymethane (AOM)-induced colon carcinogenesis, using non-invasive mini-colonoscopy. We demonstrate that both Mgmt- and Aag-null mice show a higher colon cancer frequency than the wild-type. With a single low dose of AOM (3 mg/kg) Aag-null mice showed an even stronger tumor response than Mgmt-null mice. The data provide evidence that both BER initiated by Aag and O(6)MeG reversal by Mgmt are required for protection against alkylation-induced colon carcinogenesis. Further, the data indicate that non-repaired N-methylpurines are not only pre-toxic but also pre-carcinogenic DNA lesions.
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Affiliation(s)
- Stefan Wirtz
- Department of Molecular Medicine, University of Erlangen-Nuremberg, D-91052 Erlangen, German
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Nikolova T, Ensminger M, Löbrich M, Kaina B. Homologous recombination protects mammalian cells from replication-associated DNA double-strand breaks arising in response to methyl methanesulfonate. DNA Repair (Amst) 2010; 9:1050-63. [PMID: 20708982 DOI: 10.1016/j.dnarep.2010.07.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Revised: 07/02/2010] [Accepted: 07/08/2010] [Indexed: 11/19/2022]
Abstract
DNA-methylating agents of the S(N)2 type target DNA mostly at ring nitrogens, producing predominantly N-methylated purines. These adducts are repaired by base excision repair (BER). Since defects in BER cause accumulation of DNA single-strand breaks (SSBs) and sensitize cells to the agents, it has been suggested that some of the lesions on their own or BER intermediates (e.g. apurinic sites) are cytotoxic, blocking DNA replication and inducing replication-mediated DNA double-strand breaks (DSBs). Here, we addressed the question of whether homologous recombination (HR) or non-homologous end-joining (NHEJ) or both are involved in the repair of DSBs formed following treatment of cells with methyl methanesulfonate (MMS). We show that HR defective cells (BRCA2, Rad51D and XRCC3 mutants) are dramatically more sensitive to MMS-induced DNA damage as measured by colony formation, apoptosis and chromosomal aberrations, while NHEJ defective cells (Ku80 and DNA-PK(CS) mutants) are only mildly sensitive to the killing, apoptosis-inducing and clastogenic effects of MMS. On the other hand, the HR mutants were almost completely refractory to the formation of sister chromatid exchanges (SCEs) following MMS treatment. Since DSBs are expected to be formed specifically in the S-phase, we assessed the formation and kinetics of repair of DSBs by γH2AX quantification in a cell cycle specific manner. In the cytotoxic dose range of MMS a significant amount of γH2AX foci was induced in S, but not G1- and G2-phase cells. A major fraction of γH2AX foci colocalized with 53BP1 and phosphorylated ATM, indicating they are representative of DSBs. DSB formation following MMS treatment was also demonstrated by the neutral comet assay. Repair kinetics revealed that HR mutants exhibit a significant delay in DSB repair, while NHEJ mutants completed S-phase specific DSB repair with a kinetic similar to the wildtype. Moreover, DNA-PKcs inhibition in HR mutants did not affect the repair kinetics after MMS treatment. Overall, the data indicate that agents producing N-alkylpurines in the DNA induce replication-dependent DSBs. Further, they show that HR is the major pathway of protection of cells against DSB formation, killing and genotoxicity following S(N)2-alkylating agents.
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Affiliation(s)
- Teodora Nikolova
- Institute of Toxicology, Medical Center of the University Mainz, Obere Zahlbacher Str 67, D-55131 Mainz, Germany
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Asagoshi K, Tano K, Chastain PD, Adachi N, Sonoda E, Kikuchi K, Koyama H, Nagata K, Kaufman DG, Takeda S, Wilson SH, Watanabe M, Swenberg JA, Nakamura J. FEN1 functions in long patch base excision repair under conditions of oxidative stress in vertebrate cells. Mol Cancer Res 2010; 8:204-15. [PMID: 20145043 DOI: 10.1158/1541-7786.mcr-09-0253] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
From in vitro studies, flap endonuclease 1 (FEN1) has been proposed to play a role in the long patch (LP) base excision repair (BER) subpathway. Yet the role of FEN1 in BER in the context of the living vertebrate cell has not been thoroughly explored. In the present study, we cloned a DT40 chicken cell line with a deletion in the FEN1 gene and found that these FEN1-deficient cells exhibited hypersensitivity to H(2)O(2). This oxidant produces genotoxic lesions that are repaired by BER, suggesting that the cells have a deficiency in BER affecting survival. In experiments with extracts from the isogenic FEN1 null and wild-type cell lines, the LP-BER activity of FEN1 null cells was deficient, whereas repair by the single-nucleotide BER subpathway was normal. Other consequences of the FEN1 deficiency were also evaluated. These results illustrate that FEN1 plays a role in LP-BER in higher eukaryotes, presumably by processing the flap-containing intermediates of BER.
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Affiliation(s)
- Kenjiro Asagoshi
- Laboratory of Structural Biology, NIEHS, NIH, Research Triangle Park, North Carolina, USA
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