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Kneuttinger AC, Kashiwazaki G, Prill S, Heil K, Müller M, Carell T. Formation and Direct Repair of UV-induced Dimeric DNA Pyrimidine Lesions. Photochem Photobiol 2013; 90:1-14. [PMID: 24354557 DOI: 10.1111/php.12197] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/17/2013] [Indexed: 12/11/2022]
Abstract
Direct repair of UV-induced DNA lesions represents an elegant method for many organisms to deal with these highly mutagenic and cytotoxic compounds. Although the participating proteins are structurally well investigated, the exact repair mechanism of the photolyase enzymes remains a vivid subject of current research. In this review, we summarize and highlight the recent contributions to this exciting field.
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Affiliation(s)
- Andrea Christa Kneuttinger
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Gengo Kashiwazaki
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Stefan Prill
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Korbinian Heil
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Markus Müller
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Thomas Carell
- Center for Integrated Protein Sciences at the Department of Chemistry, Ludwig-Maximilians Universität München, Munich, Germany
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102
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Mesa R, Bassnett S. UV-B-induced DNA damage and repair in the mouse lens. Invest Ophthalmol Vis Sci 2013; 54:6789-97. [PMID: 24022010 DOI: 10.1167/iovs.13-12644] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE Epidemiologic studies have linked UV-B exposure to development of cortical cataracts, but the underlying molecular mechanism(s) is unresolved. Here, we used a mouse model to examine the nature and distribution of DNA photolesions produced by ocular UV-B irradiation. METHODS Anesthetized mice, eye globes, or isolated lenses were exposed to UV-B. Antibodies specific for 6-4 photoproducts (6-4 PPs) or cyclobutane pyrimidine dimers (CPDs) were used to visualize DNA adducts. RESULTS Illumination of intact globes with UV-B-induced 6-4 PP and CPD formation in cells of the cornea, anterior iris, and central lens epithelium. Photolesions were not detected in retina or lens cells situated in the shadow of the iris. Photolesions in lens epithelial cells were produced with radiant exposures significantly below the minimal erythemal dose. Lens epithelial cells rapidly repaired 6-4 PPs, but CPD levels did not markedly diminish, even over extended postirradiation recovery periods in vitro or in vivo. The repair of 6-4 PPs did not depend on the proliferative activity of the epithelial cells, since the repair rate in the mitotically-active germinative zone (GZ) was indistinguishable from that of quiescent cells in the central epithelium. CONCLUSIONS Even relatively modest exposures to UV-B produced 6-4 PP and CPD photolesions in lens epithelial cells. Cyclobutane pyrimidine dimer lesions were particularly prevalent and were repaired slowly if at all. Studies on sun-exposed skin have established a causal connection between photolesions and so-called UV-signature mutations. If similar mechanisms apply in the lens, it suggests that somatic mutations in lens epithelial cells may contribute to the development of cortical cataracts.
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Affiliation(s)
- Rosana Mesa
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri
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103
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Boros G, Miko E, Muramatsu H, Weissman D, Emri E, Rózsa D, Nagy G, Juhász A, Juhász I, van der Horst G, Horkay I, Remenyik É, Karikó K, Emri G. Transfection of pseudouridine-modified mRNA encoding CPD-photolyase leads to repair of DNA damage in human keratinocytes: a new approach with future therapeutic potential. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 129:93-9. [PMID: 24211294 DOI: 10.1016/j.jphotobiol.2013.09.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/26/2013] [Accepted: 09/29/2013] [Indexed: 12/19/2022]
Abstract
UVB irradiation induces harmful photochemical reactions, including formation of Cyclobutane Pyrimidine Dimers (CPDs) in DNA. Accumulation of unrepaired CPD lesions causes inflammation, premature ageing and skin cancer. Photolyases are DNA repair enzymes that can rapidly restore DNA integrity in a light-dependent process called photoreactivation, but these enzymes are absent in humans. Here, we present a novel mRNA-based gene therapy method that directs synthesis of a marsupial, Potorous tridactylus, CPD-photolyase in cultured human keratinocytes. Pseudouridine was incorporated during in vitro transcription to make the mRNA non-immunogenic and highly translatable. Keratinocytes transfected with lipofectamine-complexed mRNA expressed photolyase in the nuclei for at least 2days. Exposing photolyase mRNA-transfected cells to UVB irradiation resulted in significantly less CPD in those cells that were also treated with photoreactivating light, which is required for photolyase activity. The functional photolyase also diminished other UVB-mediated effects, including induction of IL-6 and inhibition of cell proliferation. These results demonstrate that pseudouridine-containing photolyase mRNA is a powerful tool to repair UVB-induced DNA lesions. The pseudouridine-modified mRNA approach has a strong potential to discern cellular effects of CPD in UV-related cell biological studies. The mRNA-based transient expression of proteins offers a number of opportunities for future application in medicine.
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Affiliation(s)
- Gábor Boros
- Department of Dermatology, Medical and Health Science Center, University of Debrecen, Nagyerdei korut 98, 4032 Debrecen, Hungary.
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104
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Ogara MF, Sirkin PF, Carcagno AL, Marazita MC, Sonzogni SV, Ceruti JM, Cánepa ET. Chromatin relaxation-mediated induction of p19INK4d increases the ability of cells to repair damaged DNA. PLoS One 2013; 8:e61143. [PMID: 23593412 PMCID: PMC3625165 DOI: 10.1371/journal.pone.0061143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 03/06/2013] [Indexed: 12/29/2022] Open
Abstract
The maintenance of genomic integrity is of main importance to the survival and health of organisms which are continuously exposed to genotoxic stress. Cells respond to DNA damage by activating survival pathways consisting of cell cycle checkpoints and repair mechanisms. However, the signal that triggers the DNA damage response is not necessarily a direct detection of the primary DNA lesion. In fact, chromatin defects may serve as initiating signals to activate those mechanisms. If the modulation of chromatin structure could initiate a checkpoint response in a direct manner, this supposes the existence of specific chromatin sensors. p19INK4d, a member of the INK4 cell cycle inhibitors, plays a crucial role in regulating genomic stability and cell viability by enhancing DNA repair. Its expression is induced in cells injured by one of several genotoxic treatments like cis-platin, UV light or neocarzinostatin. Nevertheless, when exogenous DNA damaged molecules are introduced into the cell, this induction is not observed. Here, we show that p19INK4d is enhanced after chromatin relaxation even in the absence of DNA damage. This induction was shown to depend upon ATM/ATR, Chk1/Chk2 and E2F activity, as is the case of p19INK4d induction by endogenous DNA damage. Interestingly, p19INK4d improves DNA repair when the genotoxic damage is caused in a relaxed-chromatin context. These results suggest that changes in chromatin structure, and not DNA damage itself, is the actual trigger of p19INK4d induction. We propose that, in addition to its role as a cell cycle inhibitor, p19INK4d could participate in a signaling network directed to detecting and eventually responding to chromatin anomalies.
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Affiliation(s)
- María F. Ogara
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Pablo F. Sirkin
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Abel L. Carcagno
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Mariela C. Marazita
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Silvina V. Sonzogni
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Julieta M. Ceruti
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
| | - Eduardo T. Cánepa
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, Buenos Aires, Argentina
- * E-mail:
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105
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Bowman A, Martinez-Levasseur LM, Acevedo-Whitehouse K, Gendron D, Birch-Machin MA. The simultaneous detection of mitochondrial DNA damage from sun-exposed skin of three whale species and its association with UV-induced microscopic lesions and apoptosis. Mitochondrion 2013; 13:342-9. [PMID: 23583579 DOI: 10.1016/j.mito.2013.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/21/2013] [Accepted: 04/04/2013] [Indexed: 12/22/2022]
Abstract
Due to life history and physiological constraints, cetaceans (whales) are unable to avoid prolonged exposure to external environmental insults, such as solar ultraviolet radiation (UV). The majority of studies on the effects of UV on skin are restricted to humans and laboratory animals, but it is important to develop tools to understand the effects of UV damage on large mammals such as whales, as these animals are long-lived and widely distributed, and can reflect the effects of UV across a large geographical range. We and others have used mitochondrial DNA (mtDNA) as a reliable marker of UV-induced damage particularly in human skin. UV-induced mtDNA strand breaks or lesions accumulate throughout the lifespan of an individual, thus constituting an excellent biomarker for cumulative exposure. Based on our previous studies in human skin, we have developed for the first time in the literature a quantitative real-time PCR methodology to detect and quantify mtDNA lesions in skin from sun-blistered whales. Furthermore the methodology allows for simultaneous detection of mtDNA damage in different species. Therefore using 44 epidermal mtDNA samples collected from 15 blue whales, 10 fin whales, and 19 sperm whales from the Gulf of California, Mexico, we quantified damage across 4.3 kilobases, a large region of the ~16,400 base pair whale mitochondrial genome. The results show a range of mtDNA damage in the skin of the three different whale species. This previously unreported observation was correlated with apoptotic damage and microscopic lesions, both of which are markers of UV-induced damage. As is the case in human studies, this suggests the potential use of mtDNA as a biomarker for measuring the effect of cumulative UV exposure in whales and may provide a platform to help understand the effects of changing global environmental conditions.
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Affiliation(s)
- Amy Bowman
- Dermatological Sciences, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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106
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Taggart DJ, Camerlengo TL, Harrison JK, Sherrer SM, Kshetry AK, Taylor JS, Huang K, Suo Z. A high-throughput and quantitative method to assess the mutagenic potential of translesion DNA synthesis. Nucleic Acids Res 2013; 41:e96. [PMID: 23470999 PMCID: PMC3632128 DOI: 10.1093/nar/gkt141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cellular genomes are constantly damaged by endogenous and exogenous agents that covalently and structurally modify DNA to produce DNA lesions. Although most lesions are mended by various DNA repair pathways in vivo, a significant number of damage sites persist during genomic replication. Our understanding of the mutagenic outcomes derived from these unrepaired DNA lesions has been hindered by the low throughput of existing sequencing methods. Therefore, we have developed a cost-effective high-throughput short oligonucleotide sequencing assay that uses next-generation DNA sequencing technology for the assessment of the mutagenic profiles of translesion DNA synthesis catalyzed by any error-prone DNA polymerase. The vast amount of sequencing data produced were aligned and quantified by using our novel software. As an example, the high-throughput short oligonucleotide sequencing assay was used to analyze the types and frequencies of mutations upstream, downstream and at a site-specifically placed cis-syn thymidine-thymidine dimer generated individually by three lesion-bypass human Y-family DNA polymerases.
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Affiliation(s)
- David J Taggart
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio, USA
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107
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Action spectrum analysis of UVR genotoxicity for skin: the border wavelengths between UVA and UVB can bring serious mutation loads to skin. J Invest Dermatol 2013; 133:1850-6. [PMID: 23407394 DOI: 10.1038/jid.2012.504] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
UVR causes erythema, which has been used as a standardized index to evaluate the risk of UVR for human skin. However, the genotoxic significance of erythema has not been elucidated clearly. Here, we characterized the wavelength dependence of the genotoxic and erythematic effects of UVR for the skin by analyzing the induction kinetics of mutation and inflammation in mouse skin using lacZ-transgenic mice and monochromatic UVR sources. We determined their action spectra and found a close correlation between erythema and an epidermis-specific antigenotoxic response, mutation induction suppression (MIS), which suppressed the mutant frequencies (MFs) to a constant plateau level only 2-3-fold higher than the background MF at the cost of apoptotic cell death, suggesting that erythema may represent the threshold beyond which the antigenotoxic but tissue-destructive MIS response commences. However, we unexpectedly found that MIS attenuates remarkably at the border wavelengths between UVA and UVB around 315 nm, elevating the MF plateaus up to levels ∼40-fold higher than the background level. Thus, these border wavelengths can bring heavier mutation loads to the skin than the otherwise more mutagenic and erythematic shorter wavelengths, suggesting that erythema-based UVR risk evaluation should be reconsidered.
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108
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Lahtz C, Kim SI, Bates SE, Li AX, Wu X, Pfeifer GP. UVB irradiation does not directly induce detectable changes of DNA methylation in human keratinocytes. F1000Res 2013; 2:45. [PMID: 24555035 PMCID: PMC3901454 DOI: 10.12688/f1000research.2-45.v1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/04/2013] [Indexed: 12/18/2022] Open
Abstract
Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation.
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Affiliation(s)
- Christoph Lahtz
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Sang-In Kim
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Steven E Bates
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Arthur X Li
- Department of Information Sciences, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Xiwei Wu
- Department of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Gerd P Pfeifer
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
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109
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Budden T, Bowden NA. The role of altered nucleotide excision repair and UVB-induced DNA damage in melanomagenesis. Int J Mol Sci 2013; 14:1132-51. [PMID: 23303275 PMCID: PMC3565312 DOI: 10.3390/ijms14011132] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/29/2012] [Accepted: 12/26/2012] [Indexed: 01/12/2023] Open
Abstract
UVB radiation is the most mutagenic component of the UV spectrum that reaches the earth's surface and causes the development of DNA damage in the form of cyclobutane pyrimidine dimers and 6-4 photoproducts. UV radiation usually results in cellular death, but if left unchecked, it can affect DNA integrity, cell and tissue homeostasis and cause mutations in oncogenes and tumour-suppressor genes. These mutations, if unrepaired, can lead to abnormal cell growth, increasing the risk of cancer development. Epidemiological data strongly associates UV exposure as a major factor in melanoma development, but the exact biological mechanisms involved in this process are yet to be fully elucidated. The nucleotide excision repair (NER) pathway is responsible for the repair of UV-induced lesions. Patients with the genetic disorder Xeroderma Pigmentosum have a mutation in one of eight NER genes associated with the XP complementation groups XP-A to XP-G and XP variant (XP-V). XP is characterized by diminished repair capacity, as well as a 1000-fold increase in the incidence of skin cancers, including melanoma. This has suggested a significant role for NER in melanoma development as a result of UVB exposure. This review discusses the current research surrounding UVB radiation and NER capacity and how further investigation of NER could elucidate the role of NER in avoiding UV-induced cellular death resulting in melanomagenesis.
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Affiliation(s)
- Timothy Budden
- Centre for Information Based Medicine, Hunter Medical Research Institute, and School of Biomedical Sciences & Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2289, Australia.
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110
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Varga Á, Marcus AP, Himoto M, Iwai S, Szüts D. Analysis of CPD ultraviolet lesion bypass in chicken DT40 cells: polymerase η and PCNA ubiquitylation play identical roles. PLoS One 2012; 7:e52472. [PMID: 23272247 PMCID: PMC3525536 DOI: 10.1371/journal.pone.0052472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/13/2012] [Indexed: 01/21/2023] Open
Abstract
Translesion synthesis (TLS) provides a mechanism of copying damaged templates during DNA replication. This potentially mutagenic process may operate either at the replication fork or at post-replicative gaps. We used the example of T-T cyclobutane pyrimidine dimer (CPD) bypass to determine the influence of polymerase recruitment via PCNA ubiquitylation versus the REV1 protein on the efficiency and mutagenic outcome of TLS. Using mutant chicken DT40 cell lines we show that, on this numerically most important UV lesion, defects in polymerase η or in PCNA ubiquitylation similarly result in the long-term failure of lesion bypass with persistent strand gaps opposite the lesion, and the elevation of mutations amongst successful TLS events. Our data suggest that PCNA ubiquitylation promotes CPD bypass mainly by recruiting polymerase η, resulting in the majority of CPD lesions bypassed in an error-free manner. In contrast, we find that polymerase ζ is responsible for the majority of CPD-dependent mutations, but has no essential function in the completion of bypass. These findings point to a hierarchy of access of the different TLS polymerases to the lesion, suggesting a temporal order of their recruitment. The similarity of REV1 and REV3 mutant phenotypes confirms that the involvement of polymerase ζ in TLS is largely determined by its recruitment to DNA by REV1. Our data demonstrate the influence of the TLS polymerase recruitment mechanism on the success and accuracy of bypass.
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Affiliation(s)
- Ágnes Varga
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Adam P. Marcus
- Division of Biomedical Sciences, St George's, University of London, London, United Kingdom
| | - Masayuki Himoto
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Shigenori Iwai
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Dávid Szüts
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
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111
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Yeo SK, Liong MT. Effects and applications of sub-lethal ultrasound, electroporation and UV radiations in bioprocessing. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-012-0559-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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112
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Cadet J, Mouret S, Ravanat JL, Douki T. Photoinduced damage to cellular DNA: direct and photosensitized reactions. Photochem Photobiol 2012; 88:1048-65. [PMID: 22780837 DOI: 10.1111/j.1751-1097.2012.01200.x] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The survey focuses on recent aspects of photochemical reactions to cellular DNA that are implicated through the predominant formation of mostly bipyrimidine photoproducts in deleterious effects of human exposure to sunlight. Recent developments in analytical methods have allowed accurate and quantitative measurements of the main DNA photoproducts in cells and human skin. Highly mutagenic CC and CT bipyrimidine photoproducts, including cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are generated in low yields with respect to TT and TC photoproducts. Another striking finding deals with the formation of Dewar valence isomers, the third class of bipyrimidine photoproducts that is accounted for by UVA-mediated isomerization of initially UVB generated 6-4PPs. Cyclobutadithymine (T<>T) has been unambiguously shown to be involved in the genotoxicity of UVA radiation. Thus, T<>T is formed in UVA-irradiated cellular DNA according to a direct excitation mechanism with a higher efficiency than oxidatively generated DNA damage that arises mostly through the Type II photosensitization mechanism. C<>C and C<>T are repaired at rates intermediate between those of T<>T and 6-4TT. Evidence has been also provided for the occurrence of photosensitized reactions mediated by exogenous agents that act either in an independent way or through photodynamic effects.
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Affiliation(s)
- Jean Cadet
- Laboratoire Lésions des Acides Nucléiques, SCIB-UMR-E n°3, CEA/UJF, Institut Nanosciences et Cryogénie, CEA/Grenoble, Grenoble Cedex, France
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113
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Kizilel R, Demir E, Azizoglu S, Asımgi H, Kavakli IH, Kizilel S. Investigation of real-time photorepair activity on DNA via surface plasmon resonance. PLoS One 2012; 7:e44392. [PMID: 22952969 PMCID: PMC3430658 DOI: 10.1371/journal.pone.0044392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 08/06/2012] [Indexed: 11/18/2022] Open
Abstract
The cyclobutane pyrimidine dimer (CPD) and 6–4 lesion formations along with the specific breaks on strands are the most common type of DNA damage caused by Ultraviolet light (UV) irradiation. CPD photolyase I and II construct two subfamilies of flavoproteins, which have recognition and repair capabilities of CPD sites on both single stranded (ssDNA) and double stranded DNA (dsDNA) with the aid of blue light energy. The other types of flavoprotein family consist of cryptochromes (CRY) that act as photoreceptors in plants, or circadian rhythm regulators in animals. Recent findings showed that a specific type of Cryptochrome-Drosophila, Arabidopsis, Synechocystis, Human (CRY-DASH) has photorepair activity on ssDNA. In this work, real-time interactions between CRY-DASH and ss/dsDNA as well as the interactions between Vibrio cholerae photolyase (VcPHR) and ss/dsDNA were investigated using Surface Plasmon Resonance (SPR). The interactions were then characterized and compared in order to investigate the effect of different types of flavoprotein on UV damaged ss/dsDNA. SPR results confirm the specific binding of VcPHR and CRY-DASH with UV treated DNA. This study is the first instance to quantify the interactions of UV treated and untreated DNA with flavoproteins.
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Affiliation(s)
- Rıza Kizilel
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
- * E-mail: (SK); (IHK); (RK)
| | - Enis Demir
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
| | - Selimcan Azizoglu
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
| | - Hande Asımgi
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
- Material Science and Engineering, Koc University, Sariyer, Istanbul, Turkey
| | - Ibrahim Halil Kavakli
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
- Material Science and Engineering, Koc University, Sariyer, Istanbul, Turkey
- Molecular Biology and Genetics, Koc University, Sariyer, Istanbul, Turkey
- * E-mail: (SK); (IHK); (RK)
| | - Seda Kizilel
- Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, Turkey
- Material Science and Engineering, Koc University, Sariyer, Istanbul, Turkey
- * E-mail: (SK); (IHK); (RK)
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114
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Yanagida J, Hammiller B, Al-Matouq J, Behrens M, Trempus CS, Repertinger SK, Hansen LA. Accelerated elimination of ultraviolet-induced DNA damage through apoptosis in CDC25A-deficient skin. Carcinogenesis 2012; 33:1754-61. [PMID: 22764135 DOI: 10.1093/carcin/bgs168] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cell division cycle 25A (CDC25A) is a dual-specificity phosphatase that removes inhibitory phosphates from cyclin-dependent kinases, allowing cell-cycle progression. Activation of cell-cycle checkpoints following DNA damage results in the degradation of CDC25A, leading to cell-cycle arrest. Ultraviolet (UV) irradiation, which causes most skin cancer, results in both DNA damage and CDC25A degradation. We hypothesized that ablation of CDC25A in the skin would increase cell-cycle arrest following UV irradiation, allowing for improved repair of DNA damage and decreased tumorigenesis. Cdc25a(fl/fl) /Krt14-Cre recombinase mice, with decreased CDC25A in the epithelium of the skin, were generated and exposed to UV. UV-induced DNA damage, in the form of cyclopyrimidine dimers and 8-oxo-deoxyguanosine adducts, was eliminated earlier from CDC25A-deficient epidermis. Surprisingly, loss of CDC25A did not alter epidermal proliferation or cell cycle after UV exposure. However, the UV-induced apoptotic response was prolonged in CDC25A-deficient skin. Double labeling of cleaved caspase-3 and the DNA damage marker γH2A.X revealed many of the apoptotic cells in UV-exposed Cdc25a mutant skin had high levels of DNA damage. Induction of skin tumors by UV irradiation of Cdc25a mutant and control mice on a skin tumor susceptible to v-ras(Ha) Tg.AC mouse background revealed UV-induced papillomas in Cdc25a mutants were significantly smaller than in controls in the first 6 weeks following UV exposure, although there was no difference in tumor multiplicity or incidence. Thus, deletion of Cdc25a increased apoptosis and accelerated the elimination of DNA damage following UV but did not substantially alter cell-cycle regulation or tumorigenesis.
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Affiliation(s)
- Jodi Yanagida
- Department of Biomedical Sciences, Creighton University School of Medicine, 2500 California Plaza Omaha, NE 68178, USA
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115
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Abstract
Skin cancer is the most common cancer in the U.S., while DNA-damaging UVB radiation from the sun remains the major environmental risk factor. Reducing skin cancer incidence is becoming an urgent issue. The energy-sensing enzyme 5’-AMP-activated protein kinase (AMPK) plays a key role in the regulation of cellular lipid and protein metabolism in response to stimuli such as exercise and changes in fuel availability. However, the role AMPK in the response of skin cells to UVB damage and in skin cancer prevention remains unknown. Here we show that AMPK activation is reduced in human and mouse squamous cell carcinoma as compared with normal skin, and by UVB irradiation, suggesting that AMPK is a tumor suppressor. At the molecular level, AMPK deletion reduced the expression of the DNA repair protein xeroderma pigmentosum C (XPC) and UVB-induced DNA repair. AMPK activation by its activators AICAR (5-aminoimidazole-4-carboxamide ribonucleoside) and metformin (N’,N’-dimethylbiguanide), the most widely used anti-diabetic drug, increased the expression of XPC expression and UVB-induced DNA repair in mouse skin, normal human epidermal keratinocytes, and AMPK wild-type cells but not in AMPK deficient cells, indicating an AMPK-dependent mechanism. Topical treatment with AICAR and metformin not only delayed onset of UVB-induced skin tumorigenesis but also reduced tumor multiplicity. Furthermore, AMPK deletion increased ERK activation and cell proliferation, while AICAR and metformin inhibited ERK activation and cell proliferation in keratinocytes, mouse skin, AMPK wild-type and AMPK deficient cells, suggesting an AMPK-independent mechanism. Finally, in UVB-damaged tumor-bearing mice, both topical and systemic metformin prevented the formation of new tumors and suppressed growth of established tumors. Our findings not only suggest that AMPK is a tumor suppressor in the skin by promoting DNA repair and controlling cell proliferation, but also demonstrate previously unknown mechanisms by which the AMPK activators prevent UVB-induced skin tumorigenesis.
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116
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Requirement of Rad18 protein for replication through DNA lesions in mouse and human cells. Proc Natl Acad Sci U S A 2012; 109:7799-804. [PMID: 22547805 DOI: 10.1073/pnas.1204105109] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In yeast, the Rad6-Rad18 ubiquitin conjugating enzyme plays a critical role in promoting replication although DNA lesions by translesion synthesis (TLS). In striking contrast, a number of studies have indicated that TLS can occur in the absence of Rad18 in human and other mammalian cells, and also in chicken cells. In this study, we determine the role of Rad18 in TLS that occurs during replication in human and mouse cells, and show that in the absence of Rad18, replication of duplex plasmids containing a cis-syn TT dimer or a (6-4) TT photoproduct is severely inhibited in human cells and that mutagenesis resulting from TLS opposite cyclobutane pyrimidine dimers and (6-4) photoproducts formed at the TT, TC, and CC dipyrimidine sites in the chromosomal cII gene in UV-irradiated mouse cells is abolished. From these and other observations with Rad18, we conclude that the Rad6-Rad18 enzyme plays an essential role in promoting replication through DNA lesions by TLS in mammalian cells. In contrast, the dispensability of Rad18 for TLS in chicken DT40 cells would suggest that the role of the Rad6-Rad18 enzyme complex has diverged considerably between chicken and mammals, raising the possibility that TLS mechanisms differ among them.
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117
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Lan L, Nakajima S, Kapetanaki MG, Hsieh CL, Fagerburg M, Thickman K, Rodriguez-Collazo P, Leuba SH, Levine AS, Rapić-Otrin V. Monoubiquitinated histone H2A destabilizes photolesion-containing nucleosomes with concomitant release of UV-damaged DNA-binding protein E3 ligase. J Biol Chem 2012; 287:12036-49. [PMID: 22334663 PMCID: PMC3320950 DOI: 10.1074/jbc.m111.307058] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
How the nucleotide excision repair (NER) machinery gains access to damaged chromatinized DNA templates and how the chromatin structure is modified to promote efficient repair of the non-transcribed genome remain poorly understood. The UV-damaged DNA-binding protein complex (UV-DDB, consisting of DDB1 and DDB2, the latter of which is mutated in xeroderma pigmentosum group E patients, is a substrate-recruiting module of the cullin 4B-based E3 ligase complex, DDB1-CUL4BDDB2. We previously reported that the deficiency of UV-DDB E3 ligases in ubiquitinating histone H2A at UV-damaged DNA sites in the xeroderma pigmentosum group E cells contributes to the faulty NER in these skin cancer-prone patients. Here, we reveal the mechanism by which monoubiquitination of specific H2A lysine residues alters nucleosomal dynamics and subsequently initiates NER. We show that DDB1-CUL4BDDB2 E3 ligase specifically binds to mononucleosomes assembled with human recombinant histone octamers and nucleosome-positioning DNA containing cyclobutane pyrimidine dimers or 6-4 photoproducts photolesions. We demonstrate functionally that ubiquitination of H2A Lys-119/Lys-120 is necessary for destabilization of nucleosomes and concomitant release of DDB1-CUL4BDDB2 from photolesion-containing DNA. Nucleosomes in which these lysines are replaced with arginines are resistant to such structural changes, and arginine mutants prevent the eviction of H2A and dissociation of polyubiquitinated DDB2 from UV-damaged nucleosomes. The partial eviction of H3 from the nucleosomes is dependent on ubiquitinated H2A Lys-119/Lys-120. Our results provide mechanistic insight into how post-translational modification of H2A at the site of a photolesion initiates the repair process and directly affects the stability of the human genome.
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Affiliation(s)
- Li Lan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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118
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Measuring the formation and repair of UV damage at the DNA sequence level by ligation-mediated PCR. Methods Mol Biol 2012; 920:189-202. [PMID: 22941605 DOI: 10.1007/978-1-61779-998-3_14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The formation and repair of DNA damage at specific locations in the genome is modulated by DNA sequence context, by DNA cytosine-5 methylation patterns, by the transcriptional status of the locus and by proteins associated with the DNA. The only method currently available to allow precise sequence mapping of DNA lesions in mammalian cells is the ligation-mediated polymerase chain reaction (LM-PCR) technique. We provide an update on technical details of LM-PCR. LM-PCR can be used, for example, for mapping of ultraviolet (UV) light-induced DNA photoproducts such as cyclobutane pyrimidine dimers.
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119
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Nakamura S, Ogasawara S, Matuda S, Saito I, Fujimoto K. Template directed reversible photochemical ligation of oligodeoxynucleotides. Molecules 2011; 17:163-78. [PMID: 22202805 PMCID: PMC6268978 DOI: 10.3390/molecules17010163] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 12/12/2022] Open
Abstract
We demonstrated that 5-vinyldeoxyuridine ((V)U) and 5-carboxyvinyldeoxyuridine ((CV)U) can be used to photoligate a longer oligonucleotide (ODN) from smaller ODNs on a template. By performing irradiation at 366 nm, these artificial nucleotides make photoligated ODNs with high efficiency without any side reactions. Moreover, by performing irradiation at 312 nm, these photoligated ODNs were reversed to the original ODN. (V)U needs to be irradiated 366 nm for 6 h, but (CV)U needs to be irradiated at 366 nm for 15 min. Finally, we made a self-assembled structure with an ODN containing (CV)U and observed the photoligated ODN by photoirradiation.
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Affiliation(s)
- Shigetaka Nakamura
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan
| | - Shinzi Ogasawara
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan
| | - Shigeo Matuda
- Department of Synthetic Chemistry and Biological Chemistry, Factly of Enginnering, Kyoto University, Kyoto 606-8501, Japan
| | - Isao Saito
- Department of Synthetic Chemistry and Biological Chemistry, Factly of Enginnering, Kyoto University, Kyoto 606-8501, Japan
| | - Kenzo Fujimoto
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan
- Research Center for Bio-Architecture, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan
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120
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Mouret S, Forestier A, Douki T. The specificity of UVA-induced DNA damage in human melanocytes. Photochem Photobiol Sci 2011; 11:155-62. [PMID: 21986862 DOI: 10.1039/c1pp05185g] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exposure to solar UV radiation is the origin of most skin cancers, including deadly melanomas. Melanomas are quite different from keratinocyte-derived tumours and exhibit a different mutation spectrum in the activated oncogenes, possibly arising from a different class of DNA damage. In addition, some data suggest a role for UVA radiation in melanomagenesis. To get further insight into the molecular mechanisms underlying induction of melanoma, we quantified a series of UV-induced DNA damage in primary cultures of normal human melanocytes. The results were compared with those obtained in keratinocytes from the same donors. In the UVB range, the frequency and the distribution of pyrimidine dimers was the same in melanocytes and keratinocytes. UVA was also found to produce thymine cyclobutane dimer as the major DNA lesion with an equal efficiency in both cell types. In contrast, following UVA-irradiation a large difference was found for the yield of 8-oxo-7,8-dihydroguanine; the level of this product was 2.2-fold higher in melanocytes than in keratinocytes. The comet assay showed that the induction of strand breaks was equally efficient in both cell types but that the yield of Fpg-sensitive sites was larger in melanocytes. Our data show that, upon UVA irradiation, oxidative lesions contribute to a larger extent to DNA damage in melanocytes than in keratinocytes. We also observed that the basal level of oxidative lesions was higher in the melanocytes, in agreement with a higher oxidative stress that may be due to the production of melanin. The bulk of these results, combined with qPCR and cell survival data, may explain some of the differences in mutation spectrum and target genes between melanomas and carcinomas arising from keratinocytes.
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Affiliation(s)
- Stéphane Mouret
- Laboratoire Lésions des Acides Nucléiques, SCIB, UMR-E3 CEA/UJF-Grenoble 1, INAC, Grenoble, F-38054, France
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121
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Pfeifer GP, Besaratinia A. UV wavelength-dependent DNA damage and human non-melanoma and melanoma skin cancer. Photochem Photobiol Sci 2011; 11:90-7. [PMID: 21804977 DOI: 10.1039/c1pp05144j] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ultraviolet (UV) irradiation from the sun has been epidemiologically and mechanistically linked to skin cancer, a spectrum of diseases of rising incidence in many human populations. Both non-melanoma and melanoma skin cancers are associated with sunlight exposure. In this review, we discuss the UV wavelength-dependent formation of the major UV-induced DNA damage products, their repair and mutagenicity and their potential involvement in sunlight-associated skin cancers. We emphasize the major role played by the cyclobutane pyrimidine dimers (CPDs) in skin cancer mutations relative to that of (6-4) photoproducts and oxidative DNA damage. Collectively, the data implicate the CPD as the DNA lesion most strongly involved in human cancers induced by sunlight.
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Affiliation(s)
- Gerd P Pfeifer
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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122
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Nagira T, Narisawa J, Teruya K, Katakura Y, Shim SY, Kusumoto KI, Tokumaru S, Tokumaru K, Barnes DW, Shirahata S. Suppression of UVC-induced cell damage and enhancement of DNA repair by the fermented milk, Kefir. Cytotechnology 2011; 40:125-37. [PMID: 19003113 DOI: 10.1023/a:1023984304610] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An aqueous extract of Kefir, fermented milk originally produced in the Caucasus mountains, suppressed morphological changes of human melanoma HMV-1 and SK-MEL cells and human normal fibroblastTIG-1 cells caused by UVC-irradiation, suggesting that UV damage can be suppressed by the Kefir extract. The addition of the Kefir extract after UVC-irradiation of HVM-1 cells resulted in a remarkable decrease in intracellular reactive oxygen species (ROS) which had been increased by UVC irradiation. The Kefir extract also stimulated unscheduled DNA synthesis and suppressed UVC-induced apoptosis of HMV-1 cells. A colony formation assay revealed that the Kefir extract rescued HMV-1 cells from cell death caused by UVC irradiation. The Kefir extract, as well as methyl methanethiosulfonate which is known to enhance the nucleotide excision repair (NER) activity, exhibited strong thymine dimer repair-enhancing activity. Epigalocatechin exhibited a weak NER activity but vitamins A, C, and E and catechin showed no NER activity. The thymine dimer repair-enhancing factors in the Kefir extract were heat-stable and assumed to be molecules with a molecular weight of less than 5000. The treatment of HMV-1 cells with the Kefir extract during or before UVC- irradiation also prevented the generation of ROS and thymine dimmer, and suppressed the apoptosis of HMV-1 cells, suggesting that application of Kefir can prevent UV damage.
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Affiliation(s)
- Tsutomu Nagira
- Department of Genetic Resources Technology, Faculty of Agriculture, Graduate School of Kyushu University, Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
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123
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Besaratinia A, Yoon JI, Schroeder C, Bradforth SE, Cockburn M, Pfeifer GP. Wavelength dependence of ultraviolet radiation-induced DNA damage as determined by laser irradiation suggests that cyclobutane pyrimidine dimers are the principal DNA lesions produced by terrestrial sunlight. FASEB J 2011; 25:3079-91. [PMID: 21613571 DOI: 10.1096/fj.11-187336] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
To elucidate the involvement of specific ultraviolet (UV) wavelengths in solar mutagenesis, we used a laser system to investigate the induction of DNA damage, both in the overall genome and at the nucleotide resolution level, in the genomic DNA of transgenic Big Blue mouse fibroblasts irradiated with a series of UV wavelengths, inclusive of UVC (λ<280 nm), UVB (λ=280-320 nm), and UVA (λ>320 nm). Subsequently, we sought correlation between the locations of UV-induced DNA lesions in the cII transgene of irradiated DNA samples and the frequency distribution and codon position of the induced cII mutations in counterpart mouse cells irradiated with simulated sunlight. Using a combination of enzymatic digestion assays coupled with gel electrophoresis, immunodot blot assays, and DNA footprinting assays, we demonstrated a unique wavelength-dependent formation of photodimeric lesions, i.e., cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts [(6-4)PPs], based on direct UV absorption of DNA, in irradiated mouse genomic DNA, which could partially explain the induction of mutations in mouse cells irradiated with simulated sunlight. Most notably, there was a divergence of CPD and (6-4)PP formation at an irradiation wavelength of 296 nm in mouse genomic DNA. Whereas substantial formation of (6-4)PPs was detectable in samples irradiated at this wavelength, which intensified as the irradiation wavelength decreased, only small quantities of these lesions were found in samples irradiated at wavelengths of 300-305 nm, with no detectable level of (6-4)PPs in samples irradiated with longer wavelengths. Although CPD formation followed the same pattern of increase with decreasing wavelengths of irradiation, there were substantial levels of CPDs in samples irradiated with UVB wavelengths borderlined with UVA, and small but detectable levels of these lesions in samples irradiated with longer wavelengths. Because the terrestrial sunlight spectrum rolls off sharply at wavelengths ~300 nm, our findings suggest that CPDs are the principal lesion responsible for most DNA damage-dependent biological effects of sunlight.
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Affiliation(s)
- Ahmad Besaratinia
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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124
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Mouret S, Leccia MT, Bourrain JL, Douki T, Beani JC. Individual photosensitivity of human skin and UVA-induced pyrimidine dimers in DNA. J Invest Dermatol 2011; 131:1539-46. [PMID: 21430702 DOI: 10.1038/jid.2011.47] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Delineation of the DNA-damaging properties of UVA radiation is a major issue in understanding solar carcinogenesis. Emphasis was placed in this study on the formation of cyclobutane pyrimidine dimers (CPDs), which are now well established as the most frequent UVA-induced DNA lesions in human skin. The yield of CPDs was determined by a chromatographic assay following ex vivo UVA and UVB irradiation of biopsies taken from either phototype II or IV volunteers. A clear correlation was found between the frequency of UVB-induced CPDs and both the phototype and the minimum erythemal dose (MED). Similar results were obtained for the induction of CPDs upon exposure to UVA. Moreover, an excellent correlation was observed for each donor between the yield of DNA damage induced by either UVB or UVA. These observations show that the key parameters driving UVA-induced formation of CPDs are attenuation of radiation in the skin and the number of photons reaching skin cells rather than the cellular content in photosensitizers. In addition, the results show that both MED and phototype are good predictors of the vulnerability of DNA toward UVB and UVA in the skin. This result is of importance for the identification of individuals to be extensively protected.
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Affiliation(s)
- Stéphane Mouret
- CEA, INAC, SCIB, UJF & CNRS, LCIB (UMR_E 3 CEA-UJF & FRE 3200), Laboratoire Lésions des Acides Nucléiques, Grenoble, France
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125
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Hassanali AA, Zhong D, Singer SJ. An AIMD study of the CPD repair mechanism in water: reaction free energy surface and mechanistic implications. J Phys Chem B 2011; 115:3848-59. [PMID: 21417374 DOI: 10.1021/jp107722z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In a series of two papers, we report the detailed mechanism of cyclobutane pyrimidine dimer repair in aqueous solvent using ab initio molecular dynamics simulations (AIMD). Umbrella sampling is used to determine the free energy surface for dimer splitting. The two-dimensional free energy surface for splitting of the C5-C5' and C6-C6' bonds on the anion surface is reported. The splitting of the C5-C5' and C6-C6' bonds occurs on a picosecond time scale. The transition state along the splitting coordinate in the anion state coincides with a maximum in the free energy along the same coordinate on the neutral surface. The implication is that back electron transfer occurring before the anion reaches the transition state leads to reformation of the cyclobutane dimer, while back electron transfer after transit through the transition state, leads to successful repair. On the basis of our calculations for CPD splitting in water, we propose a framework for understanding how various factors, such as solvent polarity, can control repair efficiency. This framework explains why back electron transfer leads predominantly to unsuccessful repair in some situations, and successful repair in others. A key observation is that the same free energy surfaces that control dimer splitting also govern how the back electron transfer rate changes during the splitting process. Configurational changes of the dimer along the splitting coordinate are also documented.
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Affiliation(s)
- Ali A Hassanali
- Biophysics Program, Ohio State University, Columbus, Ohio 43210, USA.
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126
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Role of human DNA polymerase κ in extension opposite from a cis-syn thymine dimer. J Mol Biol 2011; 408:252-61. [PMID: 21354175 DOI: 10.1016/j.jmb.2011.02.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/15/2011] [Accepted: 02/17/2011] [Indexed: 11/23/2022]
Abstract
Exposure of DNA to UV radiation causes covalent linkages between adjacent pyrimidines. The most common lesion found in DNA from these UV-induced linkages is the cis-syn cyclobutane pyrimidine dimer. Human DNA polymerase κ (Polκ), a member of the Y-family of DNA polymerases, is unable to insert nucleotides opposite the 3'T of a cis-syn T-T dimer, but it can efficiently extend from a nucleotide inserted opposite the 3'T of the dimer by another DNA polymerase. We present here the structure of human Polκ in the act of inserting a nucleotide opposite the 5'T of the cis-syn T-T dimer. The structure reveals a constrained active-site cleft that is unable to accommodate the 3'T of a cis-syn T-T dimer but is remarkably well adapted to accommodate the 5'T via Watson-Crick base pairing, in accord with a proposed role for Polκ in the extension reaction opposite from cyclobutane pyrimidine dimers in vivo.
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127
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Gening LV. DNA polymerase ι of mammals as a participant in translesion synthesis of DNA. BIOCHEMISTRY (MOSCOW) 2011; 76:61-8. [DOI: 10.1134/s0006297911010081] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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128
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Abstract
Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: "error-free" bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases--the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation.
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Affiliation(s)
- Hironobu Ikehata
- Division of Genome and Radiation Biology, Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
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129
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Song Q, Cannistraro VJ, Taylor JS. Rotational position of a 5-methylcytosine-containing cyclobutane pyrimidine dimer in a nucleosome greatly affects its deamination rate. J Biol Chem 2010; 286:6329-35. [PMID: 21160086 DOI: 10.1074/jbc.m110.183178] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
C to T mutation hotspots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. These mutations are proposed to arise from the insertion of A by DNA polymerase η opposite the T that results from deamination of the methylC ((m)C) within the CPD. Although the frequency of CPD formation and repair is modestly modulated by its rotational position within a nucleosome, the effect of position on the rate of (m)C deamination in a CPD has not been previously studied. We now report that deamination of a T(m)C CPD whose sugar phosphate backbone is positioned against the histone core surface decreases by a factor of 4.7, whereas that of a T(m)C CPD positioned away from the surface increases by a factor of 8.9 when compared with unbound DNA. Because the (m)Cs undergoing deamination are in similar steric environments, the difference in rate appears to be a consequence of a difference in the flexibility and compression of the two sites due to DNA bending. Considering that formation of the CPD positioned away from the surface is also enhanced by a factor of two, a T(m)CG site in this position might be expected to have up to an 84-fold higher probability of resulting in a UV-induced (m)C to T mutation than one positioned against the surface. These results indicate that rotational position may play an important role in the formation of UV-induced C to T mutation hotspots, as well as in the mutagenic mechanism of other DNA lesions.
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Affiliation(s)
- Qian Song
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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130
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Mouret S, Bogdanowicz P, Haure MJ, Castex-Rizzi N, Cadet J, Favier A, Douki T. Assessment of the Photoprotection Properties of Sunscreens by Chromatographic Measurement of DNA Damage in Skin Explants. Photochem Photobiol 2010; 87:109-16. [DOI: 10.1111/j.1751-1097.2010.00834.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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131
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Mitchell DL, Fernandez AA. Different types of DNA damage play different roles in the etiology of sunlight-induced melanoma. Pigment Cell Melanoma Res 2010; 24:119-24. [PMID: 20955242 DOI: 10.1111/j.1755-148x.2010.00789.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David L Mitchell
- Department of Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA.
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132
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Büchner N, Altschmied J, Jakob S, Saretzki G, Haendeler J. Well-known signaling proteins exert new functions in the nucleus and mitochondria. Antioxid Redox Signal 2010; 13:551-8. [PMID: 19958149 DOI: 10.1089/ars.2009.2994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
One distinguishing feature of eukaryotic cells is their compartmentalization into organelles, which all have a unique structural and functional identity. Some proteins are exclusively localized in a single organelle, whereas others are found in more than one. A few proteins, whose function was thought to be completely understood, were only recently found to be present in the mitochondria. Although these proteins come from diverse functional classes, their common new denominator is the regulation of respiratory chain activity. Therefore, this review focuses on new functions of the Signal Transducer and Activator of Transcription 3, originally described as a transcription factor, the most prominent Src kinase family members, Src, Fyn, and Yes, which were so far known as plasma membrane-associated molecular effectors of a variety of extracellular stimuli, the tyrosine phosphatase Shp-2 previously characterized as a modulator of cytosolic signal transduction involved in cell growth, development, inflammation, and chemotaxis, and Telomerase Reverse Transcriptase, the key enzyme preventing telomere erosion in the nucleus. Their unexpected localization in other organelles and regulation of mitochondrial and/or nuclear functions by them adds a new layer of regulatory complexity. This extends the flexibility to cope with changing environmental demands using a limited number of genes and proteins.
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Affiliation(s)
- Nicole Büchner
- Leibniz-Institute for Molecular Preventive Medicine, University of Duesseldorf , Duesseldorf, Germany
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133
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Castells E, Molinier J, Drevensek S, Genschik P, Barneche F, Bowler C. det1-1-induced UV-C hyposensitivity through UVR3 and PHR1 photolyase gene over-expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:392-404. [PMID: 20487384 DOI: 10.1111/j.1365-313x.2010.04249.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Obligate photoautotrophs such as plants must capture energy from sunlight and are therefore exposed to the damaging collateral effects of ultraviolet (UV) irradiation, especially on DNA. Here we investigated the interconnection between light signaling and DNA repair, two concomitant pathways during photomorphogenesis, the developmental transition associated with the first light exposure. It is shown that combination of an enhanced sunscreen effect and photoreactivation confers a greater level of tolerance to damaging UV-C doses in the constitutive photomorphogenic de-etiolated1-1 (det1--1) Arabidopsis mutant. In darkness, expression of the PHR1 and UVR3 photolyase genes, responsible for photoreactivation, is maintained at a basal level through the positive action of HY5 and HYH photomorphogenesis-promoting transcription factors and the repressive effects of DET1 and COP1. Upon light exposure, HY5 and HYH activate PHR1 gene expression while the constitutively expressed nuclear-localized DET1 protein exerts a strong inhibitory effect. Altogether, the data presented indicate a dual role for DET1 in controlling expression of light-responsive and DNA repair genes, and describe more precisely the contribution of photomorphogenic regulators in the control of light-dependent DNA repair.
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Affiliation(s)
- Enric Castells
- Environmental and Evolutionary Genomics, CNRS UMR8197, Institut de Biologie de l'Ecole Normale Supérieure, 46 rue d'Ulm, F-75230 Paris Cedex 05, FranceInstitut de Biologie Moléculaire des Plantes du CNRS (UPR2357), conventionné avec l'Université Louis Pasteur, Strasbourg, France
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134
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Yoon JH, Prakash L, Prakash S. Error-free replicative bypass of (6-4) photoproducts by DNA polymerase zeta in mouse and human cells. Genes Dev 2010; 24:123-8. [PMID: 20080950 DOI: 10.1101/gad.1872810] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ultraviolet (UV)-induced (6-4) pyrimidine-pyrimidone photoproduct [(6-4) PP] confers a large structural distortion in DNA. Here we examine in human cells the roles of translesion synthesis (TLS) DNA polymerases (Pols) in promoting replication through a (6-4) TT photoproduct carried on a duplex plasmid where bidirectional replication initiates from an origin of replication. We show that TLS contributes to a large fraction of lesion bypass and that it is mostly error-free. We find that, whereas Pol eta and Pol iota provide alternate pathways for mutagenic TLS, surprisingly, Pol zeta functions independently of these Pols and in a predominantly error-free manner. We verify and extend these observations in mouse cells and conclude that, in human cells, TLS during replication can be markedly error-free even opposite a highly distorting DNA lesion.
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Affiliation(s)
- Jung-Hoon Yoon
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555, USA
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135
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Mouret S, Philippe C, Gracia-Chantegrel J, Banyasz A, Karpati S, Markovitsi D, Douki T. UVA-induced cyclobutane pyrimidine dimers in DNA: a direct photochemical mechanism? Org Biomol Chem 2010; 8:1706-11. [PMID: 20237685 DOI: 10.1039/b924712b] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The carcinogenic action of UVA radiation is commonly attributed to DNA oxidation mediated by endogenous photosensitisers. Yet, it was recently shown that cyclobutane pyrimidine dimers (CPD), well known for their involvement in UVB genotoxicity, are produced in larger yield than oxidative lesions in UVA-irradiated cells and skin. In the present work, we gathered mechanistic information on this photoreaction by comparing formation of all possible bipyrimidine photoproducts upon UVA irradiation of cells, purified genomic DNA and dA(20):dT(20) oligonucleotide duplex. We observed that the distribution of photoproducts, characterized by the sole formation of CPD and the absence of (6-4) photoproducts was similar in the three types of samples. The CPD involving two thymines represented 90% of the amount of photoproducts. Moreover, the yields of formation of the DNA lesions were similar in cells and isolated DNA. In addition, the effect of the wavelength of the incident photons was found to be the same in isolated DNA and cells. This set of data shows that UVA-induced cyclobutane pyrimidine dimers are formed via a direct photochemical mechanism, without mediation of a cellular photosensitiser. This is possible because the double-stranded structure increases the capacity of DNA bases to absorb UVA photons, as evidenced in the case of the oligomer dA(20):dT(20). These results emphasize the need to consider UVA in the carcinogenic effects of sunlight. An efficient photoprotection is needed that can only be complete by completely blocking incident photons, rather than by systemic approaches such as antioxidant supplementation.
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Affiliation(s)
- Stéphane Mouret
- DSM/INAC/SCIB UMR-E 3 CEA/UJF FRE CNRS 3200/Laboratoire Lésions des Acides Nucléiques, CEA-Grenoble, France
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136
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Rasmussen AM, Lind MC, Kim S, Schaefer HF. Hydration of the Lowest Triplet States of the DNA/RNA Pyrimidines. J Chem Theory Comput 2010; 6:930-9. [DOI: 10.1021/ct900478c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrew M. Rasmussen
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Maria C. Lind
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Sunghwan Kim
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
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137
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Schumacher B. Transcription-blocking DNA damage in aging: a mechanism for hormesis. Bioessays 2009; 31:1347-56. [DOI: 10.1002/bies.200900107] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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138
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Highly error-free role of DNA polymerase eta in the replicative bypass of UV-induced pyrimidine dimers in mouse and human cells. Proc Natl Acad Sci U S A 2009; 106:18219-24. [PMID: 19822754 DOI: 10.1073/pnas.0910121106] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cyclobutane pyrimidine dimers (CPDs) constitute the most frequent UV-induced DNA photoproduct. However, it has remained unclear how human and other mammalian cells mitigate the mutagenic and carcinogenic potential of CPDs emanating from their replicative bypass. Here, we examine in human cells the roles of translesion synthesis (TLS) DNA polymerases (Pols) in the replicative bypass of a cis-syn TT dimer carried on the leading or the lagging strand DNA template in a plasmid system we have designed, and we determine in mouse cells the frequencies and mutational spectra generated from TLS occurring specifically opposite CPDs formed at TT, TC, and CC dipyrimidine sites. From these studies we draw the following conclusions: (i) TLS makes a very prominent contribution to CPD bypass on both the DNA strands during replication; (ii) Pols eta, kappa, and zeta provide alternate pathways for TLS opposite CPDs wherein Pols kappa and zeta promote mutagenic TLS opposite CPDs; and (iii) the absence of mutagenic TLS events opposite a cis-syn TT dimer in human cells and opposite CPDs formed at TT, TC, and CC sites in mouse cells that we observe upon the simultaneous knockdown of Pols kappa and zeta implicates a highly error-free role of Poleta in TLS opposite CPDs in mammalian cells. Such a remarkably high in vivo fidelity of Poleta could not have been anticipated in view of its low intrinsic fidelity. These observations have important bearing on how mammalian cells have adapted to avoid the mutagenic and carcinogenic consequences of exposure to sunlight.
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139
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Pagès V, Santa Maria SR, Prakash L, Prakash S. Role of DNA damage-induced replication checkpoint in promoting lesion bypass by translesion synthesis in yeast. Genes Dev 2009; 23:1438-49. [PMID: 19528320 DOI: 10.1101/gad.1793409] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Unrepaired DNA lesions in the template strand block the replication fork. In yeast, Mec1 protein kinase-mediated replication checkpoint prevents the breakdown of replication forks and maintains viability in DNA-damaged cells going through the S phase. By ensuring that the replisome does not dissociate from the fork stalled at the lesion site, the replication checkpoint presumably coordinates the action of lesion bypass processes with the replisome. However, it has remained unclear as to which of the lesion bypass processes-translesion synthesis (TLS) and/or template switching-depend on the activation of the replication checkpoint. Here we determine if the Mec1 kinase and the subunits of the checkpoint clamp and the clamp loader are required for TLS. We show that proficient TLS can occur in the absence of these checkpoint proteins in nucleotide excision repair (NER)-proficient cells; however, in the absence of NER, checkpoint protein-mediated Rev1 phosphorylation contributes to increasing the proficiency of DNA polymerase zeta-dependent TLS.
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Affiliation(s)
- Vincent Pagès
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555, USA
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140
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Prior SL, Griffiths AP, Lewis PD. A study of mitochondrial DNA D-loop mutations and p53 status in nonmelanoma skin cancer. Br J Dermatol 2009; 161:1067-71. [PMID: 19624548 DOI: 10.1111/j.1365-2133.2009.09304.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) displacement-loop (D-loop) mutations have previously demonstrated potential as smoking-induced biomarkers in oral squamous cell carcinoma (SCC). Additionally, they have been observed in SCC and basal cell carcinoma of nonmelanoma skin cancer (NMSC). However, they have not been examined in the SCC precursor lesions, Bowen disease or actinic keratosis. OBJECTIVES Here, we present a novel study of mtDNA D-loop mutations in these two precursors, a rare keratoacanthoma and NMSC (all tumours not related to smoking). METHODS We used a polymerase chain reaction and direct sequencing approach. Furthermore, as the tumour suppressor protein p53 has been reported as having a novel role in maintaining mitochondrial genetic stability, we assessed p53 status using immunohistochemistry, evaluating potential association with the presence of mtDNA mutations. RESULTS Of 36 tumours, nine (25%) exhibited mutations in the D-loop. In total, 13 base substitutions were observed across all patients: seven (53.8%) were A : T to G : C; two (15.4%) were G : C to T : A; two (15.4%) were G : C to A : T and two (15.4%) were G : C to C : G. Four of the 13 (30.8%) base substitutions were observed at nucleotide 146. We observed abnormal p53 accumulation in over half of the samples analysed (55.5%), suggesting it to be a major part of the carcinogenic process of NMSC; however; there was no association between p53 positivity and the presence of mtDNA mutations (P = 0.47). CONCLUSIONS It is unlikely that alteration in p53 status is a contributing factor to mtDNA mutagenesis.
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Affiliation(s)
- S L Prior
- School of Medicine, Institute of Life Science, Swansea University, Singleton Park, Swansea, UK.
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141
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Persistent transcription-blocking DNA lesions trigger somatic growth attenuation associated with longevity. Nat Cell Biol 2009; 11:604-15. [PMID: 19363488 PMCID: PMC2782455 DOI: 10.1038/ncb1866] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 02/05/2009] [Indexed: 12/22/2022]
Abstract
The accumulation of stochastic DNA damage throughout an organism's lifespan is thought to contribute to ageing. Conversely, ageing seems to be phenotypically reproducible and regulated through genetic pathways such as the insulin-like growth factor-1 (IGF-1) and growth hormone (GH) receptors, which are central mediators of the somatic growth axis. Here we report that persistent DNA damage in primary cells from mice elicits changes in global gene expression similar to those occurring in various organs of naturally aged animals. We show that, as in ageing animals, the expression of IGF-1 receptor and GH receptor is attenuated, resulting in cellular resistance to IGF-1. This cell-autonomous attenuation is specifically induced by persistent lesions leading to stalling of RNA polymerase II in proliferating, quiescent and terminally differentiated cells; it is exacerbated and prolonged in cells from progeroid mice and confers resistance to oxidative stress. Our findings suggest that the accumulation of DNA damage in transcribed genes in most if not all tissues contributes to the ageing-associated shift from growth to somatic maintenance that triggers stress resistance and is thought to promote longevity.
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142
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Murphy AK, Tammaro M, Cortazar F, Gindt YM, Schelvis JPM. Effect of the cyclobutane cytidine dimer on the properties of Escherichia coli DNA photolyase. J Phys Chem B 2009; 112:15217-26. [PMID: 18973361 DOI: 10.1021/jp806526y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclobutane pyrimidine dimer (CPD) photolyases are structure specific DNA-repair enzymes that specialize in the repair of CPDs, the major photoproducts that are formed upon irradiation of DNA with ultraviolet light. The purified enzyme binds a flavin adenine dinucleotide (FAD), which is in the neutral radical semiquinone (FADH(*)) form. The CPDs are repaired by a light-driven, electron transfer from the anionic hydroquinone (FADH(-)) singlet excited state to the CPD, which is followed by reductive cleavage of the cyclobutane ring and subsequent monomerization of the pyrimidine bases. CPDs formed between two adjacent thymidine bases (T< >T) are repaired with greater efficiency than those formed between two adjacent cytidine bases (C< >C). In this paper, we investigate the changes in Escherichia coli photolyase that are induced upon binding to DNA containing C< >C lesions using resonance Raman, UV-vis absorption, and transient absorption spectroscopies, spectroelectrochemistry, and computational chemistry. The binding of photolyase to a C< >C lesion modifies the energy levels of FADH(*), the rate of charge recombination between FADH(-) and Trp(306)(*), and protein-FADH(*) interactions differently than binding to a T< >T lesion. However, the reduction potential of the FADH(-)/FADH(*) couple is modified in the same way with both substrates. Our calculations show that the permanent electric dipole moment of C< >C is stronger (12.1 D) and oriented differently than that of T< >T (8.7 D). The possible role of the electric dipole moment of the CPD in modifying the physicochemical properties of photolyase as well as in affecting CPD repair will be discussed.
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Affiliation(s)
- Anar K Murphy
- Department of Chemistry, New York University, New York, New York 10003, USA
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143
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Zhu SY, Yi JP, Shen WD, Wang LQ, He HG, Wang Y, Li B, Wang WB. Genomic sequence, organization and characteristics of a new nucleopolyhedrovirus isolated from Clanis bilineata larva. BMC Genomics 2009; 10:91. [PMID: 19243590 PMCID: PMC2650706 DOI: 10.1186/1471-2164-10-91] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 02/25/2009] [Indexed: 12/03/2022] Open
Abstract
Background Baculoviruses are well known for their potential as biological agents for controlling agricultural and forest pests. They are also widely used as expression vectors in molecular cloning studies. The genome sequences of 48 baculoviruses are currently available in NCBI databases. As the number of sequenced viral genomes increases, it is important for the authors to present sufficiently detailed analyses and annotations to advance understanding of them. In this study, the complete genome of Clanis bilineata nucleopolyhedrovirus (ClbiNPV) has been sequenced and analyzed in order to understand this virus better. Results The genome of ClbiNPV contains 135,454 base pairs (bp) with a G+C content of 37%, and 139 putative open reading frames (ORFs) of at least 150 nucleotides. One hundred and twenty-six of these ORFs have homologues with other baculovirus genes while the other 13 are unique to ClbiNPV. The 30 baculovirus core genes are all present in ClbiNPV. Phylogenetic analysis based on the combined pif-2 and lef-8 sequences places ClbiNPV in the Group II Alphabaculoviruses. This result is consistent with the absence of gp64 from the ClbiNPV genome and the presence instead of a fusion protein gene, characteristic of Group II. Blast searches revealed that ClbiNPV encodes a photolyase-like gene sequence, which has a 1-bp deletion when compared with photolyases of other baculoviruses. This deletion disrupts the sequence into two small photolyase ORFs, designated Clbiphr-1 and Clbiphr-2, which correspond to the CPD-DNA photolyase and FAD-binding domains of photolyases, respectively. Conclusion ClbiNPV belongs to the Group II Alphabaculoviruses and is most closely related to OrleNPV, LdMNPV, TnSNPV, EcobNPV and ChchNPV. It contains a variant DNA photolyase gene, which only exists in ChchNPV, TnSNPV and SpltGV among the baculoviruses.
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Affiliation(s)
- Shan-Ying Zhu
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, PR China.
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144
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Lucas-Lledó JI, Lynch M. Evolution of mutation rates: phylogenomic analysis of the photolyase/cryptochrome family. Mol Biol Evol 2009; 26:1143-53. [PMID: 19228922 DOI: 10.1093/molbev/msp029] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photoreactivation, one of the first DNA repair pathways to evolve, is the direct reversal of premutagenic lesions caused by ultraviolet (UV) irradiation, catalyzed by photolyases in a light-dependent, single-enzyme reaction. It has been experimentally shown that photoreactivation prevents UV mutagenesis in a broad range of species. In the absence of photoreactivation, UV-induced photolesions are repaired by the more complex and much less efficient nucleotide excision repair pathway. Despite their obvious beneficial effects, several lineages, including placental mammals, lost photolyase genes during evolution. In this study, we ask why photolyase genes have been lost in those lineages and discuss the significance of these losses in the context of the evolution of the genomic mutation rates. We first perform an extensive phylogenomic analysis of the photolyase/cryptochrome family, to assess what species lack each kind of photolyase gene. Then, we estimate the ratio of nonsynonymous to synonymous substitution rates in several groups of photolyase genes, as a proxy of the strength of purifying natural selection, and we ask whether less evolutionarily constrained photolyase genes are more likely lost. We also review functional data and compare the efficiency of different kinds of photolyases. We find that eukaryotic photolyases are, on average, less evolutionarily constrained than eubacterial ones and that the strength of natural selection is correlated with the affinity of photolyases for their substrates. We propose that the loss of photolyase genes in eukaryotic species may be due to weak natural selection and may result in a deleterious increase of their genomic mutation rates. In contrast, the loss of photolyase genes in prokaryotes may not cause an increase in the mutation rate and be neutral in most cases.
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145
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p53 Protein and Pathogenesis of Melanoma and Nonmelanoma Skin Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 624:265-82. [DOI: 10.1007/978-0-387-77574-6_21] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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146
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Vreeswijk MPG, Meijers CM, Giphart-Gassler M, Vrieling H, van Zeeland AA, Mullenders LHF, Loenen WAM. Site-specific analysis of UV-induced cyclobutane pyrimidine dimers in nucleotide excision repair-proficient and -deficient hamster cells: Lack of correlation with mutational spectra. Mutat Res 2008; 663:7-14. [PMID: 19150617 DOI: 10.1016/j.mrfmmm.2008.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 12/16/2008] [Accepted: 12/19/2008] [Indexed: 12/14/2022]
Abstract
Irradiation of cells with UVC light induces two types of mutagenic DNA photoproducts, i.e. cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4 PP). To investigate the relationship between the frequency of UV-induced photolesions at specific sites and their ability to induce mutations, we quantified CPD formation at the nucleotide level along exons 3 and 8 of the hprt gene using ligation-mediated PCR, and determined the mutational spectrum of 132 UV-induced hprt mutants in the AA8 hamster cell line and of 165 mutants in its nucleotide excision repair-defective derivative UV5. In AA8 cells, transversions predominated with a strong strand bias towards thymine-containing photolesions in the non-transcribed strand. As hamster AA8 cells are proficient in global genome repair of 6-4 PP but selectively repair CPD from the transcribed strand of active genes, most mutations probably resulted from erroneous bypass of CPD in the non-transcribed strand. However, the relative incidence of CPD and the positions where mutations most frequently arose do not correlate. In fact some major damage sites hardly gave rise to the formation of mutations. In the repair-defective UV5 cells, mutations were almost exclusively C>T transitions caused by photoproducts at PyC sites in the transcribed strand. Even though CPD were formed at high frequencies at some TT sites in UV5, these photoproducts did not contribute to mutation induction at all. We conclude that, even in the absence of repair, large variations in the level of induction of CPD at different sites throughout the two exons do not correspond to frequencies of mutation induction.
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Affiliation(s)
- Maaike P G Vreeswijk
- Department of Toxicogenetics, Leiden University Medical Center, Leiden, The Netherlands.
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147
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Aguilar-Fuentes J, Fregoso M, Herrera M, Reynaud E, Braun C, Egly JM, Zurita M. p8/TTDA overexpression enhances UV-irradiation resistance and suppresses TFIIH mutations in a Drosophila trichothiodystrophy model. PLoS Genet 2008; 4:e1000253. [PMID: 19008953 PMCID: PMC2576456 DOI: 10.1371/journal.pgen.1000253] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 10/03/2008] [Indexed: 11/25/2022] Open
Abstract
Mutations in certain subunits of the DNA repair/transcription factor complex TFIIH are linked to the human syndromes xeroderma pigmentosum (XP), Cockayne's syndrome (CS), and trichothiodystrophy (TTD). One of these subunits, p8/TTDA, interacts with p52 and XPD and is important in maintaining TFIIH stability. Drosophila mutants in the p52 (Dmp52) subunit exhibit phenotypic defects similar to those observed in TTD patients with defects in p8/TTDA and XPD, including reduced levels of TFIIH. Here, we demonstrate that several Dmp52 phenotypes, including lethality, developmental defects, and sterility, can be suppressed by p8/TTDA overexpression. TFIIH levels were also recovered in rescued flies. In addition, p8/TTDA overexpression suppressed a lethal allele of the Drosophila XPB homolog. Furthermore, transgenic flies overexpressing p8/TTDA were more resistant to UV irradiation than were wild-type flies, apparently because of enhanced efficiency of cyclobutane-pyrimidine-dimers and 6–4 pyrimidine-pyrimidone photoproducts repair. This study is the first using an intact higher-animal model to show that one subunit mutant can trans-complement another subunit in a multi-subunit complex linked to human diseases. TFIIH participates in RNA polymerase II transcription, nucleotide excision repair, and control of the cell cycle. In humans, certain mutations in the XPB and XPD subunits of TFIIH generate the syndromes trichothiodystrophy (TTD), xeroderma pigmentosum (XP), and Cockayne's syndrome (CS). In contrast, mutations in the p8/TTDA subunit have been linked only to TTD. Cells derived from TTD patients with defects in p8/TTDA have reduced levels of TFIIH. Therefore, it has been proposed that the main function of p8/TTDA is to stabilize and maintain steady-state levels of TFIIH. In Drosophila, mutations in Dmp52 and haywire genes generate phenotypes that share similarities with those associated with mutations in their human counterparts, including reduced TFIIH levels. We report that p8/TTDA overexpression suppressed accumulated developmental defects associated with mutations in the Dmp52 and haywire genes. We also provide evidence suggesting that the rescue of these defects is, in part, because of the recovery of normal TFIIH levels in mutant flies. These results indicate that overexpression of p8/TTDA trans-complemented mutations in other TFIIH subunits and suppressed defects accumulated during fly development. The overexpression of p8/TTDA in wild-type flies increased their UV irradiation resistance, apparently because of more efficient nucleotide excision repair.
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Affiliation(s)
- Javier Aguilar-Fuentes
- Department of Developmental Genetics, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Mariana Fregoso
- Department of Developmental Genetics, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Mariana Herrera
- Department of Developmental Genetics, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Enrique Reynaud
- Department of Developmental Genetics, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Cathy Braun
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, C.U. de Strasbourg, France
| | - Jean Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, C.U. de Strasbourg, France
| | - Mario Zurita
- Department of Developmental Genetics, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
- * E-mail:
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148
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Liapis E, McLuckie KIE, Lewis PD, Farmer PB, Brown K. Mutagenicity of tamoxifen DNA adducts in human endometrial cells and in silico prediction of p53 mutation hotspots. Nucleic Acids Res 2008; 36:5933-45. [PMID: 18805907 PMCID: PMC2566887 DOI: 10.1093/nar/gkn586] [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] [Indexed: 02/07/2023] Open
Abstract
Tamoxifen elevates the risk of endometrial tumours in women and alpha-(N(2)-deoxyguanosinyl)-tamoxifen adducts are reportedly present in endometrial tissue of patients undergoing therapy. Given the widespread use of tamoxifen there is considerable interest in elucidating the mechanisms underlying treatment-associated cancer. Using a combined experimental and multivariate statistical approach we have examined the mutagenicity and potential consequences of adduct formation by reactive intermediates in target uterine cells. pSP189 plasmid containing the supF gene was incubated with alpha-acetoxytamoxifen or 4-hydroxytamoxifen quinone methide (4-OHtamQM) to generate dG-N(2)-tamoxifen and dG-N(2)-4-hydroxytamoxifen, respectively. Plasmids were replicated in Ishikawa cells then screened in Escherichia coli. Treatment with both alpha-acetoxytamoxifen and 4-OHtamQM caused a dose-related increase in adduct levels, resulting in a damage-dependent increase in mutation frequency for alpha-acetoxytamoxifen; 4-OHtamQM had no apparent effect. Only alpha-acetoxytamoxifen generated statistically different supF mutation spectra relative to the spontaneous pattern, with most mutations being GC-->TA transversions. Application of the LwPy53 algorithm to the alpha-acetoxytamoxifen spectrum predicted strong GC-->TA hotspots at codons 244 and 273. These signature alterations do not correlate with current reports of the mutations observed in endometrial carcinomas from treated women, suggesting that dG-N(2)-tam adduct formation in the p53 gene is not a prerequisite for endometrial cancer initiation in women.
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Affiliation(s)
- Evagelos Liapis
- Department of Cancer Studies and Molecular Medicine, Department of Biochemistry, University of Leicester, Leicester, LE2 7LX, UK
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Hendel A, Ziv O, Gueranger Q, Geacintov N, Livneh Z. Reduced efficiency and increased mutagenicity of translesion DNA synthesis across a TT cyclobutane pyrimidine dimer, but not a TT 6-4 photoproduct, in human cells lacking DNA polymerase eta. DNA Repair (Amst) 2008; 7:1636-46. [PMID: 18634905 DOI: 10.1016/j.dnarep.2008.06.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Revised: 06/05/2008] [Accepted: 06/12/2008] [Indexed: 01/06/2023]
Abstract
Xeroderma pigmentosum variant (XPV) patients carry germ-line mutations in DNA polymerase eta (poleta), a major translesion DNA synthesis (TLS) polymerase, and exhibit severe sunlight sensitivity and high predisposition to skin cancer. Using a quantitative TLS assay system based on gapped plasmids we analyzed TLS across a site-specific TT CPD (thymine-thymine cyclobutane pyrimidine dimer) or TT 6-4 PP (thymine-thymine 6-4 photoproduct) in three pairs of poleta-proficient and deficient human cells. TLS across the TT CPD lesion was reduced by 2.6-4.4-fold in cells lacking poleta, and exhibited a strong 6-17-fold increase in mutation frequency at the TT CPD. All targeted mutations (74%) in poleta-deficient cells were opposite the 3'T of the CPD, however, a significant fraction (23%) were semi-targeted to the nearest nucleotides flanking the CPD. Deletions and insertions were observed at a low frequency, which increased in the absence of poleta, consistent with the formation of double strand breaks due to defective TLS. TLS across TT 6-4 PP was about twofold lower than across CPD, and was marginally reduced in poleta-deficient cells. TLS across TT 6-4 PP was highly mutagenic (27-63%), with multiple mutations types, and no significant difference between cells with or without poleta. Approximately 50% of the mutations formed were semi-targeted, of which 84-93% were due to the insertion of an A opposite the template G 5' to the 6-4 PP. These results, which are consistent with the UV hyper-mutability of XPV cells, highlight the critical role of poleta in error-free TLS across CPD in human cells, and suggest a potential involvement, although minor, of poleta in TLS across 6-4 PP under some conditions.
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Affiliation(s)
- Ayal Hendel
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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150
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Faurschou A, Gniadecki R, Wulf HC. Infliximab inhibits DNA repair in ultraviolet B-irradiated premalignant keratinocytes. Exp Dermatol 2008; 17:933-8. [PMID: 18557931 DOI: 10.1111/j.1600-0625.2008.00727.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Anti-tumor necrosis factor-alpha (TNFalpha) approaches are increasingly used in the therapy of autoimmune diseases. One of the safety concerns is the potential enhancement of skin carcinogenesis. The aim of this study was to investigate if the TNFalpha neutralizing antibody, infliximab, directly affects the cell cycle and DNA repair in premalignant human keratinocytes after ultraviolet-B (UVB) irradiation. We found that infliximab-treated cells exhibited an enhanced G2/M cell cycle arrest and increased apoptosis after 10-20 mJ/cm(2) UVB. In spite of this, the level of cyclobutane pyrimidine dimers (CPD) in infliximab-treated cells was significantly increased at both 24 and 48 h after irradiation with 10 mJ/cm(2) UVB. As we have recently shown that protein kinase B/Akt is involved in the TNFalpha signalling pathway and promotes cell survival and skin carcinogenesis, we measured activatory phosphorylations of Akt (Ser-473 and Thr-308) and the signalling via related pathways Erk 1/2, p38 and p70-S6K. Infliximab inhibited Akt and its downstream targets p70-S6K and Erk 1/2, and stimulated p38 both in sham-irradiated and UVB-irradiated cells. In conclusion, despite the fact that infliximab blocks Akt and stimulates the G2/M checkpoint and apoptosis in UVB-irradiated keratinocytes, the repair of CPD is impaired. It is conceivable that anti-TNFalpha treatments may contribute to the accumulation of mutagenic lesions in the epidermis and enhance the early stages of skin carcinogenesis.
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Affiliation(s)
- Annesofie Faurschou
- Department of Dermatology, University of Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark.
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