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Chai J, Su M, Zhang R, Li N, Jia Y, Zheng W, Tan J, Jia Q, Sun H, Meng Z. Selective anti-tumor activity of glutathione-responsive abasic site trapping agent in anaplastic thyroid carcinoma. BMC Cancer 2024; 24:816. [PMID: 38977966 PMCID: PMC11229194 DOI: 10.1186/s12885-024-12511-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 06/12/2024] [Indexed: 07/10/2024] Open
Abstract
Anaplastic thyroid carcinoma (ATC) is a rare but highly aggressive thyroid cancer with poor prognosis. Killing cancer cells by inducing DNA damage or blockage of DNA repair is a promising strategy for chemotherapy. It is reported that aldehyde-reactive alkoxyamines can capture the AP sites, one of the most common DNA lesions, and inhibit apurinic/apyrimidinic endonuclease 1(APE1)-mediated base excision repair (BER), leading to cell death. Whether this strategy can be employed for ATC treatment is rarely investigated. The aim of this study is to exploit GSH-responsive AP site capture reagent (AP probe-net), which responses to the elevated glutathione (GSH) levels in the tumor micro-environment (TME), releasing reactive alkoxyamine to trap AP sites and block the APE1-mediated BER for targeted anti-tumor activity against ATC. In vitro experiments, including MTT andγ-H2AX assays, demonstrate their selective cytotoxicity towards ATC cells over normal thyroid cells. Flow cytometry analysis suggests that AP probe-net arrests the cell cycle in the G2/M phase and induces apoptosis. Western blotting (WB) results show that the expression of apoptotic protein increased with the increased concentration of AP probe-net. Further in vivo experiments reveal that the AP probe-net has a good therapeutic effect on subcutaneous tumors of the ATC cells. In conclusion, taking advantage of the elevated GSH in TME, our study affords a new strategy for targeted chemotherapy of ATC with high selectivity and reduced adverse effects.
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Affiliation(s)
- Jinyan Chai
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Mengxue Su
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Ruiguo Zhang
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Ning Li
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Yuanyuan Jia
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Wei Zheng
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Jian Tan
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Qiang Jia
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China
| | - Huabing Sun
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Medical University, Tianjin, 300070, P. R. China.
| | - Zhaowei Meng
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Anshan Road No. 154, He ping District, Tianjin, 300052, P.R. China.
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2
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Kim DV, Diatlova EA, Zharkov TD, Melentyev VS, Yudkina AV, Endutkin AV, Zharkov DO. Back-Up Base Excision DNA Repair in Human Cells Deficient in the Major AP Endonuclease, APE1. Int J Mol Sci 2023; 25:64. [PMID: 38203235 PMCID: PMC10778768 DOI: 10.3390/ijms25010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Apurinic/apyrimidinic (AP) sites are abundant DNA lesions generated both by spontaneous base loss and as intermediates of base excision DNA repair. In human cells, they are normally repaired by an essential AP endonuclease, APE1, encoded by the APEX1 gene. Other enzymes can cleave AP sites by either hydrolysis or β-elimination in vitro, but it is not clear whether they provide the second line of defense in living cells. Here, we studied AP site repairs in APEX1 knockout derivatives of HEK293FT cells using a reporter system based on transcriptional mutagenesis in the enhanced green fluorescent protein gene. Despite an apparent lack of AP site-processing activity in vitro, the cells efficiently repaired the tetrahydrofuran AP site analog resistant to β-elimination. This ability persisted even when the second AP endonuclease homolog, APE2, was also knocked out. Moreover, APEX1 null cells were able to repair uracil, a DNA lesion that is removed via the formation of an AP site. If AP site hydrolysis was chemically blocked, the uracil repair required the presence of NTHL1, an enzyme that catalyzes β-elimination. Our results suggest that human cells possess at least two back-up AP site repair pathways, one of which is NTHL1-dependent.
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Affiliation(s)
- Daria V. Kim
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Evgeniia A. Diatlova
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Timofey D. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Vasily S. Melentyev
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Anna V. Yudkina
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Anton V. Endutkin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Dmitry O. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
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3
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Laughery MF, Plummer DA, Wilson HE, Vandenberg BN, Mitchell D, Mieczkowski PA, Roberts SA, Wyrick JJ. Genome-wide maps of UVA and UVB mutagenesis in yeast reveal distinct causative lesions and mutational strand asymmetries. Genetics 2023; 224:iyad086. [PMID: 37170598 PMCID: PMC10324949 DOI: 10.1093/genetics/iyad086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/01/2023] [Accepted: 05/03/2023] [Indexed: 05/13/2023] Open
Abstract
Ultraviolet (UV) light primarily causes C > T substitutions in lesion-forming dipyrimidine sequences. However, many of the key driver mutations in melanoma do not fit this canonical UV signature, but are instead caused by T > A, T > C, or C > A substitutions. To what extent exposure to the UVB or UVA spectrum of sunlight can induce these noncanonical mutation classes, and the molecular mechanism involved is unclear. Here, we repeatedly exposed wild-type or repair-deficient yeast (Saccharomyces cerevisiae) to UVB or UVA light and characterized the resulting mutations by whole genome sequencing. Our data indicate that UVB induces C > T and T > C substitutions in dipyrimidines, and T > A substitutions that are often associated with thymine-adenine (TA) sequences. All of these mutation classes are induced in nucleotide excision repair-deficient cells and show transcriptional strand asymmetry, suggesting they are caused by helix-distorting UV photoproducts. In contrast, UVA exposure induces orders of magnitude fewer mutations with a distinct mutation spectrum. UVA-induced mutations are elevated in Ogg1-deficient cells, and the resulting spectrum consists almost entirely of C > A/G > T mutations, indicating they are likely derived from oxidative guanine lesions. These mutations show replication asymmetry, with elevated G > T mutations on the leading strand, suggesting there is a strand bias in the removal or bypass of guanine lesions during replication. Finally, we develop a mutation reporter to show that UVA induces a G > T reversion mutation in yeast that mimics the oncogenic NRAS Q61K mutation in melanoma. Taken together, these findings indicate that UVA and UVB exposure can induce many of the noncanonical mutation classes that cause driver mutations in melanoma.
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Affiliation(s)
- Marian F Laughery
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Dalton A Plummer
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Hannah E Wilson
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Brittany N Vandenberg
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Debra Mitchell
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Piotr A Mieczkowski
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
- Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - John J Wyrick
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
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4
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Endutkin AV, Yudkina AV, Zharkov TD, Kim DV, Zharkov DO. Recognition of a Clickable Abasic Site Analog by DNA Polymerases and DNA Repair Enzymes. Int J Mol Sci 2022; 23:ijms232113353. [PMID: 36362137 PMCID: PMC9655677 DOI: 10.3390/ijms232113353] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Azide–alkyne cycloaddition (“click chemistry”) has found wide use in the analysis of molecular interactions in living cells. 5-ethynyl-2-(hydroxymethyl)tetrahydrofuran-3-ol (EAP) is a recently developed apurinic/apyrimidinic (AP) site analog functionalized with an ethynyl moiety, which can be introduced into cells in DNA constructs to perform labeling or cross-linking in situ. However, as a non-natural nucleoside, EAP could be subject to removal by DNA repair and misreading by DNA polymerases. Here, we investigate the interaction of this clickable AP site analog with DNA polymerases and base excision repair enzymes. Similarly to the natural AP site, EAP was non-instructive and followed the “A-rule”, directing residual but easily detectable incorporation of dAMP by E. coli DNA polymerase I Klenow fragment, bacteriophage RB69 DNA polymerase and human DNA polymerase β. On the contrary, EAP was blocking for DNA polymerases κ and λ. EAP was an excellent substrate for the major human AP endonuclease APEX1 and E. coli AP exonucleases Xth and Nfo but was resistant to the AP lyase activity of DNA glycosylases. Overall, our data indicate that EAP, once within a cell, would represent a replication block and would be removed through an AP endonuclease-initiated long-patch base excision repair pathway.
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Affiliation(s)
- Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Timofey D. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Daria V. Kim
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
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5
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Cai Y, Cao H, Wang F, Zhang Y, Kapranov P. Complex genomic patterns of abasic sites in mammalian DNA revealed by a high-resolution SSiNGLe-AP method. Nat Commun 2022; 13:5868. [PMID: 36198706 PMCID: PMC9534904 DOI: 10.1038/s41467-022-33594-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 09/23/2022] [Indexed: 11/30/2022] Open
Abstract
DNA damage plays a critical role in biology and diseases; however, how different types of DNA lesions affect cellular functions is far from clear mostly due to the paucity of high-resolution methods that can map their locations in complex genomes, such as those of mammals. Here, we present the development and validation of SSiNGLe-AP method, which can map a common type of DNA damage, abasic (AP) sites, in a genome-wide and high-resolution manner. We apply this method to six different tissues of mice with different ages and human cancer cell lines. We find a nonrandom distribution of AP sites in the mammalian genome that exhibits dynamic enrichment at specific genomic locations, including single-nucleotide hotspots, and is significantly influenced by gene expression, age and tissue type in particular. Overall, these results suggest that we are only starting to understand the true complexities in the genomic patterns of DNA damage.
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Affiliation(s)
- Ye Cai
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, 361021, Xiamen, China
| | - Huifen Cao
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, 361021, Xiamen, China.
| | - Fang Wang
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, 361021, Xiamen, China
| | - Yufei Zhang
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, 361021, Xiamen, China
| | - Philipp Kapranov
- Institute of Genomics, School of Medicine, Huaqiao University, 668 Jimei Road, 361021, Xiamen, China.
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6
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Tan Y, You C, Park J, Kim HS, Guo S, Schärer OD, Wang Y. Transcriptional Perturbations of 2,6-Diaminopurine and 2-Aminopurine. ACS Chem Biol 2022; 17:1672-1676. [PMID: 35700389 DOI: 10.1021/acschembio.2c00369] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
2,6-Diaminopurine (Z) is a naturally occurring adenine (A) analog that bacteriophages employ in place of A in their genetic alphabet. Recent discoveries of biogenesis pathways of Z in bacteriophages have stimulated substantial research interest in this DNA modification. Here, we systematically examined the effects of Z on the efficiency and fidelity of DNA transcription. Our results showed that Z exhibited no mutagenic yet substantial inhibitory effects on transcription mediated by purified T7 RNA polymerase and by human RNA polymerase II in HeLa nuclear extracts and in human cells. A structurally related adenine analog, 2-aminopurine (2AP), strongly blocked T7 RNA polymerase but did not impede human RNA polymerase II in vitro or in human cells, where no mutant transcript could be detected. The lack of mutagenic consequence and the presence of a strong blockage effect of Z on transcription suggest a role of Z in transcriptional regulation. Z is also subjected to removal by transcription-coupled nucleotide-excision repair (TC-NER), but not global-genome NER in human cells. Our findings provide new insight into the effects of Z on transcription and its potential biological functions.
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Affiliation(s)
| | | | - Jiyeong Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Hyun Suk Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | | | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
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7
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Kapoor I, Shaw A, Naha A, Emam EAF, Varshney U. Role of the nucleotide excision repair pathway proteins (UvrB and UvrD2) in recycling UdgB, a base excision repair enzyme in Mycobacterium smegmatis. DNA Repair (Amst) 2022; 113:103316. [PMID: 35306347 DOI: 10.1016/j.dnarep.2022.103316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/30/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022]
Abstract
Cross-talks between DNA repair pathways are emerging as a crucial strategy in the maintenance of the genomic integrity. A double-stranded (ds) DNA specific DNA glycosylase, UdgB is known to excise uracil, hypoxanthine and ethenocytosine. We earlier showed that Mycobacterium smegmatis (Msm) UdgB stays back on the AP-sites it generates in the DNA upon excision of the damaged bases. Here, we show that in an Msm strain deleted for a nucleotide excision repair (NER) protein, UvrB (uvrB-), UdgB expression is toxic, and its deletion from the genome (udgB-) rescues the strain from the genotoxic stress. However, UdgB bound AP-site is not a direct substrate for NER in vitro. We show that UvrD2 and UvrB, known helicases with single-stranded (ss) DNA translocase activity, facilitate recycling of UdgB from AP-DNA. Our studies reveal that the helicases play an important role in exposing the AP-sites in DNA and make them available for further repair.
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Affiliation(s)
- Indu Kapoor
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Abhirup Shaw
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Arindam Naha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Elhassan Ali Fathi Emam
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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8
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Duan M, Speer RM, Ulibarri J, Liu KJ, Mao P. Transcription-coupled nucleotide excision repair: New insights revealed by genomic approaches. DNA Repair (Amst) 2021; 103:103126. [PMID: 33894524 DOI: 10.1016/j.dnarep.2021.103126] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/29/2021] [Accepted: 04/12/2021] [Indexed: 01/13/2023]
Abstract
Elongation of RNA polymerase II (Pol II) is affected by many factors including DNA damage. Bulky damage, such as lesions caused by ultraviolet (UV) radiation, arrests Pol II and inhibits gene transcription, and may lead to genome instability and cell death. Cells activate transcription-coupled nucleotide excision repair (TC-NER) to remove Pol II-impeding damage and allow transcription resumption. TC-NER initiation in humans is mediated by Cockayne syndrome group B (CSB) protein, which binds to the stalled Pol II and promotes assembly of the repair machinery. Given the complex nature of the TC-NER pathway and its unique function at the interface between transcription and repair, new approaches are required to gain in-depth understanding of the mechanism. Advances in genomic approaches provide an important opportunity to investigate how TC-NER is initiated upon damage-induced Pol II stalling and what factors are involved in this process. In this Review, we discuss new mechanisms of TC-NER revealed by genome-wide DNA damage mapping and new TC-NER factors identified by high-throughput screening. As TC-NER conducts strand-specific repair of mutagenic damage, we also discuss how this repair pathway causes mutational strand asymmetry in the cancer genome.
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Affiliation(s)
- Mingrui Duan
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Rachel M Speer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Jenna Ulibarri
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Peng Mao
- Department of Internal Medicine, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, 87131, USA.
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9
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Pitucha M, Korga-Plewko A, Czylkowska A, Rogalewicz B, Drozd M, Iwan M, Kubik J, Humeniuk E, Adamczuk G, Karczmarzyk Z, Fornal E, Wysocki W, Bartnik P. Influence of Complexation of Thiosemicarbazone Derivatives with Cu (II) Ions on Their Antitumor Activity against Melanoma Cells. Int J Mol Sci 2021; 22:ijms22063104. [PMID: 33803618 PMCID: PMC8002893 DOI: 10.3390/ijms22063104] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 11/16/2022] Open
Abstract
A series of thiosemicarbazone derivatives was prepared and their anti-tumor activity in vitro was tested. The X-ray investigation performed for compounds T2, T3 and T5 confirmed the synthesis pathway and assumed molecular structures of analyzed thiosemicarbazones. The conformational preferences of the thiosemicarbazone system were characterized using theoretical calculations by AM1 method. Selected compounds were converted into complexes of Cu (II) ions. The effect of complexing on anti-tumor activity has been investigated. The copper(II) complexes, with Schiff bases T1, T10, T12, T13, and T16 have been synthesized and characterized by chemical and elemental analysis, FTIR spectroscopy and TGA method. Thermal properties of coordination compounds were studied using TG-DTG techniques under dry air atmosphere. G361, A375, and SK-MEL-28 human melanoma cells and BJ human normal fibroblast cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The compounds with the most promising anti-tumour activity were then selected and their cytotoxicity was verified with cell cycle analysis and apoptosis/necrosis detection. Additionally, DNA damages in the form of a basic sites presence and the expression of oxidative stress and DNA damage response genes were evaluated. The obtained results indicate that complexation of thiosemicarbazone derivatives with Cu (II) ions improves their antitumor activity against melanoma cells. The observed cytotoxic effect is associated with DNA damage and G2/M phase of cell cycle arrest as well as disorders of the antioxidant enzymes expression.
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Affiliation(s)
- Monika Pitucha
- Independent Radiopharmacy Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland;
- Correspondence: ; Tel.: +48-81-448-7240
| | - Agnieszka Korga-Plewko
- Independent Medical Biology Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland; (A.K.-P.); (J.K.); (E.H.); (G.A.)
| | - Agnieszka Czylkowska
- Institute of General and Ecological Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland; (A.C.); (B.R.)
| | - Bartłomiej Rogalewicz
- Institute of General and Ecological Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland; (A.C.); (B.R.)
| | - Monika Drozd
- Independent Radiopharmacy Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland;
| | - Magdalena Iwan
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland;
| | - Joanna Kubik
- Independent Medical Biology Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland; (A.K.-P.); (J.K.); (E.H.); (G.A.)
| | - Ewelina Humeniuk
- Independent Medical Biology Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland; (A.K.-P.); (J.K.); (E.H.); (G.A.)
| | - Grzegorz Adamczuk
- Independent Medical Biology Unit, Faculty of Pharmacy, Medical University of Lublin, PL-20093 Lublin, Poland; (A.K.-P.); (J.K.); (E.H.); (G.A.)
| | - Zbigniew Karczmarzyk
- Faculty of Science, Siedlce University of Natural Sciences and Humanities, 3 Maja 54, 08-110 Siedlce, Poland; (Z.K.); (W.W.); (P.B.)
| | - Emilia Fornal
- Chair and Department of Pathophysiology, Faculty of Medicine, Medical University of Lublin, PL-20090 Lublin, Poland;
| | - Waldemar Wysocki
- Faculty of Science, Siedlce University of Natural Sciences and Humanities, 3 Maja 54, 08-110 Siedlce, Poland; (Z.K.); (W.W.); (P.B.)
| | - Paulina Bartnik
- Faculty of Science, Siedlce University of Natural Sciences and Humanities, 3 Maja 54, 08-110 Siedlce, Poland; (Z.K.); (W.W.); (P.B.)
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10
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The activity of yeast Apn2 AP endonuclease at uracil-derived AP sites is dependent on the major carbon source. Curr Genet 2021; 67:283-294. [PMID: 33386486 DOI: 10.1007/s00294-020-01141-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/16/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
Yeast Apn2 is an AP endonuclease and DNA 3'-diesterase that belongs to the Exo III family with homology to the E. coli exonuclease III, Schizosaccharomyces pombe eth1, and human AP endonucleases APEX1 and APEX2. In the absence of Apn1, the major AP endonuclease in yeast, Apn2 can cleave the DNA backbone at an AP lesion initiating the base excision repair pathway. To study the role and relative contribution of Apn2, we took advantage of a reporter system that was previously used to delineate how uracil-derived AP sites are repaired. At this reporter, disruption of the Apn1-initiated base excision repair pathway led to a significant elevation of A:T to C:G transversions. Here we show that such highly elevated A:T to C:G transversion mutations associated with uracil residues in DNA are abolished when apn1∆ yeast cells are grown in glucose as the primary carbon source. We also show that the disruption of Apn2, either by the complete gene deletion or by the mutation of a catalytic residue, results in a similarly reduced rate of the uracil-associated mutations. Overall, our results indicate that Apn2 activity is regulated by the glucose repression pathway in yeast.
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11
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Thompson PS, Cortez D. New insights into abasic site repair and tolerance. DNA Repair (Amst) 2020; 90:102866. [PMID: 32417669 PMCID: PMC7299775 DOI: 10.1016/j.dnarep.2020.102866] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022]
Abstract
Thousands of apurinic/apyrimidinic (AP or abasic) sites form in each cell, each day. This simple DNA lesion can have profound consequences to cellular function, genome stability, and disease. As potent blocks to polymerases, they interfere with the reading and copying of the genome. Since they provide no coding information, they are potent sources of mutation. Due to their reactive chemistry, they are intermediates in the formation of lesions that are more challenging to repair including double-strand breaks, interstrand crosslinks, and DNA protein crosslinks. Given their prevalence and deleterious consequences, cells have multiple mechanisms of repairing and tolerating these lesions. While base excision repair of abasic sites in double-strand DNA has been studied for decades, new interest in abasic site processing has come from more recent insights into how they are processed in single-strand DNA. In this review, we discuss the source of abasic sites, their biological consequences, tolerance mechanisms, and how they are repaired in double and single-stranded DNA.
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Affiliation(s)
- Petria S Thompson
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN, 37232, USA
| | - David Cortez
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN, 37232, USA.
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12
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RNA polymerase II stalls on oxidative DNA damage via a torsion-latch mechanism involving lone pair-π and CH-π interactions. Proc Natl Acad Sci U S A 2020; 117:9338-9348. [PMID: 32284409 DOI: 10.1073/pnas.1919904117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Oxidation of guanine generates several types of DNA lesions, such as 8-oxoguanine (8OG), 5-guanidinohydantoin (Gh), and spiroiminodihydantoin (Sp). These guanine-derived oxidative DNA lesions interfere with both replication and transcription. However, the molecular mechanism of transcription processing of Gh and Sp remains unknown. In this study, by combining biochemical and structural analysis, we revealed distinct transcriptional processing of these chemically related oxidized lesions: 8OG allows both error-free and error-prone bypass, whereas Gh or Sp causes strong stalling and only allows slow error-prone incorporation of purines. Our structural studies provide snapshots of how polymerase II (Pol II) is stalled by a nonbulky Gh lesion in a stepwise manner, including the initial lesion encounter, ATP binding, ATP incorporation, jammed translocation, and arrested states. We show that while Gh can form hydrogen bonds with adenosine monophosphate (AMP) during incorporation, this base pair hydrogen bonding is not sufficient to hold an ATP substrate in the addition site and is not stable during Pol II translocation after the chemistry step. Intriguingly, we reveal a unique structural reconfiguration of the Gh lesion in which the hydantoin ring rotates ∼90° and is perpendicular to the upstream base pair planes. The perpendicular hydantoin ring of Gh is stabilized by noncanonical lone pair-π and CH-π interactions, as well as hydrogen bonds. As a result, the Gh lesion, as a functional mimic of a 1,2-intrastrand crosslink, occupies canonical -1 and +1 template positions and compromises the loading of the downstream template base. Furthermore, we suggest Gh and Sp lesions are potential targets of transcription-coupled repair.
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13
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Martínez-Arribas B, Requena CE, Pérez-Moreno G, Ruíz-Pérez LM, Vidal AE, González-Pacanowska D. DCTPP1 prevents a mutator phenotype through the modulation of dCTP, dTTP and dUTP pools. Cell Mol Life Sci 2020; 77:1645-1660. [PMID: 31377845 PMCID: PMC7162842 DOI: 10.1007/s00018-019-03250-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/05/2019] [Accepted: 07/23/2019] [Indexed: 12/02/2022]
Abstract
To maintain dNTP pool homeostasis and preserve genetic integrity of nuclear and mitochondrial genomes, the synthesis and degradation of DNA precursors must be precisely regulated. Human all-alpha dCTP pyrophosphatase 1 (DCTPP1) is a dNTP pyrophosphatase with high affinity for dCTP and 5'-modified dCTP derivatives, but its contribution to overall nucleotide metabolism is controversial. Here, we identify a central role for DCTPP1 in the homeostasis of dCTP, dTTP and dUTP. Nucleotide pools and the dUTP/dTTP ratio are severely altered in DCTPP1-deficient cells, which exhibit an accumulation of uracil in genomic DNA, the activation of the DNA damage response and both a mitochondrial and nuclear hypermutator phenotype. Notably, DNA damage can be reverted by incubation with thymidine, dUTPase overexpression or uracil-DNA glycosylase suppression. Moreover, DCTPP1-deficient cells are highly sensitive to down-regulation of nucleoside salvage. Our data indicate that DCTPP1 is crucially involved in the provision of dCMP for thymidylate biosynthesis, introducing a new player in the regulation of pyrimidine dNTP levels and the maintenance of genomic integrity.
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Affiliation(s)
- Blanca Martínez-Arribas
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Cristina E Requena
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Guiomar Pérez-Moreno
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Luis M Ruíz-Pérez
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Antonio E Vidal
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain.
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14
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Androgen receptor-binding sites are highly mutated in prostate cancer. Nat Commun 2020; 11:832. [PMID: 32047165 PMCID: PMC7012874 DOI: 10.1038/s41467-020-14644-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/20/2020] [Indexed: 12/20/2022] Open
Abstract
Androgen receptor (AR) signalling is essential in nearly all prostate cancers. Any alterations to AR-mediated transcription can have a profound effect on carcinogenesis and tumor growth. While mutations of the AR protein have been extensively studied, little is known about those somatic mutations that occur at the non-coding regions where AR binds DNA. Using clinical whole genome sequencing, we show that AR binding sites have a dramatically increased rate of mutations that is greater than any other transcription factor and specific to only prostate cancer. Demonstrating this may be common to lineage-specific transcription factors, estrogen receptor binding sites were also found to have elevated rate of mutations in breast cancer. We provide evidence that these mutations at AR binding sites, and likely other related transcription factors, are caused by faulty repair of abasic sites. Overall, this work demonstrates that non-coding AR binding sites are frequently mutated in prostate cancer and can impact enhancer activity.
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15
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Chong SY, Cutler S, Lin JJ, Tsai CH, Tsai HK, Biggins S, Tsukiyama T, Lo YC, Kao CF. H3K4 methylation at active genes mitigates transcription-replication conflicts during replication stress. Nat Commun 2020; 11:809. [PMID: 32041946 PMCID: PMC7010754 DOI: 10.1038/s41467-020-14595-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Transcription-replication conflicts (TRCs) occur when intensive transcriptional activity compromises replication fork stability, potentially leading to gene mutations. Transcription-deposited H3K4 methylation (H3K4me) is associated with regions that are susceptible to TRCs; however, the interplay between H3K4me and TRCs is unknown. Here we show that H3K4me aggravates TRC-induced replication failure in checkpoint-defective cells, and the presence of methylated H3K4 slows down ongoing replication. Both S-phase checkpoint activity and H3K4me are crucial for faithful DNA synthesis under replication stress, especially in highly transcribed regions where the presence of H3K4me is highest and TRCs most often occur. H3K4me mitigates TRCs by decelerating ongoing replication, analogous to how speed bumps slow down cars. These findings establish the concept that H3K4me defines the transcriptional status of a genomic region and defends the genome from TRC-mediated replication stress and instability. Transcription-replication conflicts (TRC) can contribute to genome instability. Here the authors reveal that under replication stress H3K4 methylation can play a role in TRC prevention.
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Affiliation(s)
- Shin Yen Chong
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan.,Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Sam Cutler
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Jing-Jer Lin
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, 10051, Taiwan
| | - Cheng-Hung Tsai
- Institute of Information Science, Academia Sinica, Nankang, Taipei, 11529, Taiwan
| | - Huai-Kuang Tsai
- Institute of Information Science, Academia Sinica, Nankang, Taipei, 11529, Taiwan
| | - Sue Biggins
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA.,Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Toshio Tsukiyama
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Yi-Chen Lo
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
| | - Cheng-Fu Kao
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan.
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16
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Kitsera N, Rodriguez-Alvarez M, Emmert S, Carell T, Khobta A. Nucleotide excision repair of abasic DNA lesions. Nucleic Acids Res 2019; 47:8537-8547. [PMID: 31226203 PMCID: PMC6895268 DOI: 10.1093/nar/gkz558] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/28/2019] [Accepted: 06/18/2019] [Indexed: 01/05/2023] Open
Abstract
Apurinic/apyrimidinic (AP) sites are a class of highly mutagenic and toxic DNA lesions arising in the genome from a number of exogenous and endogenous sources. Repair of AP lesions takes place predominantly by the base excision pathway (BER). However, among chemically heterogeneous AP lesions formed in DNA, some are resistant to the endonuclease APE1 and thus refractory to BER. Here, we employed two types of reporter constructs accommodating synthetic APE1-resistant AP lesions to investigate the auxiliary repair mechanisms in human cells. By combined analyses of recovery of the transcription rate and suppression of transcriptional mutagenesis at specifically positioned AP lesions, we demonstrate that nucleotide excision repair pathway (NER) efficiently removes BER-resistant AP lesions and significantly enhances the repair of APE1-sensitive ones. Our results further indicate that core NER components XPA and XPF are equally required and that both global genome (GG-NER) and transcription coupled (TC-NER) subpathways contribute to the repair.
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Affiliation(s)
- Nataliya Kitsera
- Unit "Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz 55131, Germany
| | - Marta Rodriguez-Alvarez
- Unit "Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz 55131, Germany
| | - Steffen Emmert
- Clinic and Policlinic for Dermatology and Venereology, University Medical Center Rostock, Rostock 18057, Germany
| | - Thomas Carell
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - Andriy Khobta
- Unit "Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz 55131, Germany
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17
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Oh J, Xu J, Chong J, Wang D. Structural and biochemical analysis of DNA lesion-induced RNA polymerase II arrest. Methods 2019; 159-160:29-34. [PMID: 30797902 DOI: 10.1016/j.ymeth.2019.02.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/30/2019] [Accepted: 02/19/2019] [Indexed: 11/16/2022] Open
Abstract
Transcription, catalyzed by RNA polymerase II (Pol II) in eukaryotes, is the first step in gene expression. RNA Pol II is a 12-subunit enzyme complex regulated by many different transcription factors during transcription initiation, elongation, and termination. During elongation, Pol II encounters various types of obstacles that can cause transcriptional pausing and arrest. Through decades of research on transcriptional pausing, it is widely known that Pol II can distinguish between different types of obstacles by its active site. A major class of obstacles is DNA lesions. While some DNA lesions can cause transient transcriptional pausing, which can be bypassed by Pol II itself or with the help from other elongation factors, bulky DNA damage can cause prolonged transcriptional pausing and arrest, which signals for transcription coupled repair. Using biochemical and structural biology approaches, the outcomes of many different types of DNA lesions, DNA modifications, and DNA binding molecules to transcription were studied. In this mini review, we will describe the in vitro transcription assays with Pol II to investigate the impacts of various DNA lesions on transcriptional outcomes and the crystallization method of lesion-arrested Pol II complex. These methods can provide a general platform for the structural and biochemical analysis of Pol II transcriptional pausing and bypass mechanisms.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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18
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Owiti N, Wei S, Bhagwat AS, Kim N. Unscheduled DNA synthesis leads to elevated uracil residues at highly transcribed genomic loci in Saccharomyces cerevisiae. PLoS Genet 2018; 14:e1007516. [PMID: 30016327 PMCID: PMC6063437 DOI: 10.1371/journal.pgen.1007516] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 07/27/2018] [Accepted: 06/26/2018] [Indexed: 12/31/2022] Open
Abstract
Recombination and mutagenesis are elevated by active transcription. The correlation between transcription and genome instability is largely explained by the topological and structural changes in DNA and the associated physical obstacles generated by the transcription machinery. However, such explanation does not directly account for the unique types of mutations originating from the non-canonical residues, uracil or ribonucleotide, which are also elevated at highly transcribed regions. Based on the previous findings that abasic (AP) lesions derived from the uracil residues incorporated into DNA in place of thymine constitute a major component of the transcription-associated mutations in yeast, we formed the hypothesis that DNA synthesis ensuing from the repair of the transcription-induced DNA damage provide the opportunity for uracil-incorporation. In support of this hypothesis, we show here the positive correlation between the level of transcription and the density of uracil residues in the yeast genome indirectly through the mutations generated by the glycosylase that excise undamaged cytosine as well as uracil. The higher uracil-density at actively transcribed regions is confirmed by the long-amplicon PCR analysis. We also show that the uracil-associated mutations at a highly transcribed region are elevated by the induced DNA damage and reduced by the overexpression of a dUTP-catalyzing enzyme Dut1 in G1- or G2-phases of the cell cycle. Overall, our results show that the DNA composition can be modified to include higher uracil-content through the non-replicative, repair-associated DNA synthesis. Uracil in DNA, a major source of spontaneous mutations, can occur through the deamination of cytosine residues or through the direct incorporation of dUTP by DNA polymerases. Recent studies in yeast have shown that the uracil-associated mutations occur more frequently at highly transcribed regions. Because the reduction in dUTP pool decreased these mutations, it was postulated that the extent of uracil-incorporation into DNA is significantly affected by the local transcription activity. We show here that the higher transcription rate does correlate with the higher uracil-density in the yeast genome. We further provide multiple lines of evidence supporting a model of uracil-incorporation into DNA that is dependent on the repair synthesis of transcription-associated DNA damage.
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Affiliation(s)
- Norah Owiti
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX United States of America
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX United States of America
| | - Shanqiao Wei
- Department of Chemistry, Wayne State University, Detroit, MI United States of America
| | - Ashok S. Bhagwat
- Department of Chemistry, Wayne State University, Detroit, MI United States of America
- Department of Biochemistry, Immunology and Microbiology, Wayne State University, Detroit, MI United States of America
| | - Nayun Kim
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX United States of America
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX United States of America
- * E-mail:
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19
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Wang W, Walmacq C, Chong J, Kashlev M, Wang D. Structural basis of transcriptional stalling and bypass of abasic DNA lesion by RNA polymerase II. Proc Natl Acad Sci U S A 2018; 115:E2538-E2545. [PMID: 29487211 PMCID: PMC5856558 DOI: 10.1073/pnas.1722050115] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Abasic sites are among the most abundant DNA lesions and interfere with DNA replication and transcription, but the mechanism of their action on transcription remains unknown. Here we applied a combined structural and biochemical approach for a comprehensive investigation of how RNA polymerase II (Pol II) processes an abasic site, leading to slow bypass of lesion. Encounter of Pol II with an abasic site involves two consecutive slow steps: insertion of adenine opposite a noninstructive abasic site (the A-rule), followed by extension of the 3'-rAMP with the next cognate nucleotide. Further studies provided structural insights into the A-rule: ATP is slowly incorporated into RNA in the absence of template guidance. Our structure revealed that ATP is bound to the Pol II active site, whereas the abasic site is located at an intermediate state above the Bridge Helix, a conserved structural motif that is cirtical for Pol II activity. The next extension step occurs in a template-dependent manner where a cognate substrate is incorporated, despite at a much slower rate compared with nondamaged template. During the extension step, neither the cognate substrate nor the template base is located at the canonical position, providing a structural explanation as to why this step is as slow as the insertion step. Taken together, our studies provide a comprehensive understanding of Pol II stalling and bypass of the abasic site in the DNA template.
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Affiliation(s)
- Wei Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Celine Walmacq
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Mikhail Kashlev
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
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The Chromatin Remodeler Isw1 Prevents CAG Repeat Expansions During Transcription in Saccharomyces cerevisiae. Genetics 2018; 208:963-976. [PMID: 29305386 PMCID: PMC5844344 DOI: 10.1534/genetics.117.300529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/02/2018] [Indexed: 12/23/2022] Open
Abstract
CAG/CTG trinucleotide repeat expansions cause several degenerative neurological and muscular diseases. Koch et al. show that the chromatin remodeling... CAG/CTG trinucleotide repeats are unstable sequences that are difficult to replicate, repair, and transcribe due to their structure-forming nature. CAG repeats strongly position nucleosomes; however, little is known about the chromatin remodeling needed to prevent repeat instability. In a Saccharomyces cerevisiae model system with CAG repeats carried on a YAC, we discovered that the chromatin remodeler Isw1 is required to prevent CAG repeat expansions during transcription. CAG repeat expansions in the absence of Isw1 were dependent on both transcription-coupled repair (TCR) and base-excision repair (BER). Furthermore, isw1∆ mutants are sensitive to methyl methanesulfonate (MMS) and exhibit synergistic MMS sensitivity when combined with BER or TCR pathway mutants. We conclude that CAG expansions in the isw1∆ mutant occur during a transcription-coupled excision repair process that involves both TCR and BER pathways. We observed increased RNA polymerase II (RNAPII) occupancy at the CAG repeat when transcription of the repeat was induced, but RNAPII binding did not change in isw1∆ mutants, ruling out a role for Isw1 remodeling in RNAPII progression. However, nucleosome occupancy over a transcribed CAG tract was altered in isw1∆ mutants. Based on the known role of Isw1 in the reestablishment of nucleosomal spacing after transcription, we suggest that a defect in this function allows DNA structures to form within repetitive DNA tracts, resulting in inappropriate excision repair and repeat-length changes. These results establish a new function for Isw1 in directly maintaining the chromatin structure at the CAG repeat, thereby limiting expansions that can occur during transcription-coupled excision repair.
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21
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Fleming AM, Zhu J, Ding Y, Burrows CJ. 8-Oxo-7,8-dihydroguanine in the Context of a Gene Promoter G-Quadruplex Is an On-Off Switch for Transcription. ACS Chem Biol 2017; 12:2417-2426. [PMID: 28829124 PMCID: PMC5604463 DOI: 10.1021/acschembio.7b00636] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Interplay
between DNA repair of the oxidatively modified base 8-oxo-7,8-dihydroguanine
(OG) and transcriptional activation has been documented in mammalian
genes. Previously, we synthesized OG into the VEGF potential G-quadruplex sequence (PQS) in the coding strand of a
luciferase promoter to identify that base excision repair (BER) unmasked
the G-quadruplex (G4) fold for gene activation. In the present work,
OG was site-specifically synthesized into a luciferase reporter plasmid
to follow the time-dependent expression in mammalian cells when OG
in the VEGF PQS context was located in the coding
vs template strands of the luciferase promoter. Removal of OG from
the coding strand by OG glycosylase-1 (OGG1)-mediated BER upregulated
transcription. When OG was in the template strand in the VEGF PQS context, transcription was downregulated by a BER-independent
process. The time course changes in transcription show that repair
in the template strand was more efficient than repair in the coding
strand. Promoters were synthesized with an OG:A base pair that requires
repair on both strands to yield a canonical G:C base pair. By monitoring
the up/down luciferase expression, we followed the timing of repair
of an OG:A base pair occurring on both strands in mammalian cells
in which one lesion resides in a G-quadruplex loop and one in a potential
i-motif. Depending on the strand in which OG resides, coding vs template,
this modification is an up/downregulator of transcription that couples
DNA repair with transcriptional regulation.
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Affiliation(s)
- Aaron M. Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Judy Zhu
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Yun Ding
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Cynthia J. Burrows
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
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22
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Chaim IA, Gardner A, Wu J, Iyama T, Wilson DM, Samson LD. A novel role for transcription-coupled nucleotide excision repair for the in vivo repair of 3,N4-ethenocytosine. Nucleic Acids Res 2017; 45:3242-3252. [PMID: 28115629 PMCID: PMC5389632 DOI: 10.1093/nar/gkx015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/20/2017] [Indexed: 12/13/2022] Open
Abstract
Etheno (ε) DNA base adducts are highly mutagenic lesions produced endogenously via reactions with lipid peroxidation (LPO) products. Cancer-promoting conditions, such as inflammation, can induce persistent oxidative stress and increased LPO, resulting in the accumulation of ε-adducts in different tissues. Using a recently described fluorescence multiplexed host cell reactivation assay, we show that a plasmid reporter bearing a site-specific 3,N4-ethenocytosine (εC) causes transcriptional blockage. Notably, this blockage is exacerbated in Cockayne Syndrome and xeroderma pigmentosum patient-derived lymphoblastoid and fibroblast cells. Parallel RNA-Seq expression analysis of the plasmid reporter identifies novel transcriptional mutagenesis properties of εC. Our studies reveal that beyond the known pathways, such as base excision repair, the process of transcription-coupled nucleotide excision repair plays a role in the removal of εC from the genome, and thus in the protection of cells and tissues from collateral damage induced by inflammatory responses.
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Affiliation(s)
- Isaac A Chaim
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alycia Gardner
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jie Wu
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility in the Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Teruaki Iyama
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - Leona D Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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23
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Thientosapol ES, Sharbeen G, Lau KKE, Bosnjak D, Durack T, Stevanovski I, Weninger W, Jolly CJ. Proximity to AGCT sequences dictates MMR-independent versus MMR-dependent mechanisms for AID-induced mutation via UNG2. Nucleic Acids Res 2017; 45:3146-3157. [PMID: 28039326 PMCID: PMC5389528 DOI: 10.1093/nar/gkw1300] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/16/2016] [Indexed: 11/30/2022] Open
Abstract
AID deaminates C to U in either strand of Ig genes, exclusively producing C:G/G:C to T:A/A:T transition mutations if U is left unrepaired. Error-prone processing by UNG2 or mismatch repair diversifies mutation, predominantly at C:G or A:T base pairs, respectively. Here, we show that transversions at C:G base pairs occur by two distinct processing pathways that are dictated by sequence context. Within and near AGCT mutation hotspots, transversion mutation at C:G was driven by UNG2 without requirement for mismatch repair. Deaminations in AGCT were refractive both to processing by UNG2 and to high-fidelity base excision repair (BER) downstream of UNG2, regardless of mismatch repair activity. We propose that AGCT sequences resist faithful BER because they bind BER-inhibitory protein(s) and/or because hemi-deaminated AGCT motifs innately form a BER-resistant DNA structure. Distal to AGCT sequences, transversions at G were largely co-dependent on UNG2 and mismatch repair. We propose that AGCT-distal transversions are produced when apyrimidinic sites are exposed in mismatch excision patches, because completion of mismatch repair would require bypass of these sites.
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Affiliation(s)
- Eddy Sanchai Thientosapol
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - George Sharbeen
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - K K Edwin Lau
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - Daniel Bosnjak
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - Timothy Durack
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - Igor Stevanovski
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - Wolfgang Weninger
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
| | - Christopher J Jolly
- Centenary Institute, Royal Prince Alfred Hospital, Camperdown NSW 2050, and Sydney Medical School, The University of Sydney, Sydney NSW 2006, Australia
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24
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Owiti N, Lopez C, Singh S, Stephenson A, Kim N. Def1 and Dst1 play distinct roles in repair of AP lesions in highly transcribed genomic regions. DNA Repair (Amst) 2017; 55:31-39. [PMID: 28521214 DOI: 10.1016/j.dnarep.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/05/2017] [Accepted: 05/06/2017] [Indexed: 12/30/2022]
Abstract
Abasic or AP sites generated by spontaneous DNA damage accumulate at a higher rate in actively transcribed regions of the genome in S. cerevisiae and are primarily repaired by base excision repair (BER) pathway. We have demonstrated that transcription-coupled nucleotide excision repair (NER) pathway can functionally replace BER to repair those AP sites located on the transcribed strand much like the strand specific repair of UV-induced pyrimidine dimers. Previous reports indicate that Rad26, a yeast homolog of transcription-repair coupling factor CSB, partly mediates strand-specific repair of UV-dimers as well as AP lesions. Here, we report that Def1, known to promote ubiquitination and degradation of stalled RNA polymerase complex, also directs NER to AP lesions on the transcribed strand of an actively transcribed gene but that its function is dependent on metabolic state of the yeast cells. We additionally show that Dst1, a homolog of mammalian transcription elongation factor TFIIS, interferes with NER-dependent repair of AP lesions while suppressing homologous recombination pathway. Overall, Def1 and Dst1 mediate very different outcomes in response to AP-induced transcription arrest.
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Affiliation(s)
- Norah Owiti
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA; The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Christopher Lopez
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Shivani Singh
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Andrei Stephenson
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Nayun Kim
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA; The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.
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25
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Saini N, Roberts SA, Sterling JF, Malc EP, Mieczkowski PA, Gordenin DA. APOBEC3B cytidine deaminase targets the non-transcribed strand of tRNA genes in yeast. DNA Repair (Amst) 2017; 53:4-14. [PMID: 28351647 DOI: 10.1016/j.dnarep.2017.03.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/23/2017] [Accepted: 03/10/2017] [Indexed: 01/08/2023]
Abstract
Variations in mutation rates across the genome have been demonstrated both in model organisms and in cancers. This phenomenon is largely driven by the damage specificity of diverse mutagens and the differences in DNA repair efficiency in given genomic contexts. Here, we demonstrate that the single-strand DNA-specific cytidine deaminase APOBEC3B (A3B) damages tRNA genes at a 1000-fold higher efficiency than other non-tRNA genomic regions in budding yeast. We found that A3B-induced lesions in tRNA genes were predominantly located on the non-transcribed strand, while no transcriptional strand bias was observed in protein coding genes. Furthermore, tRNA gene mutations were exacerbated in cells where RNaseH expression was completely abolished (Δrnh1Δrnh35). These data suggest a transcription-dependent mechanism for A3B-induced tRNA gene hypermutation. Interestingly, in strains proficient in DNA repair, only 1% of the abasic sites formed upon excision of A3B-deaminated cytosines were not repaired leading to mutations in tRNA genes, while 18% of these lesions failed to be repaired in the remainder of the genome. A3B-induced mutagenesis in tRNA genes was found to be efficiently suppressed by the redundant activities of both base excision repair (BER) and the error-free DNA damage bypass pathway. On the other hand, deficiencies in BER did not have a profound effect on A3B-induced mutations in CAN1, the reporter for protein coding genes. We hypothesize that differences in the mechanisms underlying ssDNA formation at tRNA genes and other genomic loci are the key determinants of the choice of the repair pathways and consequently the efficiency of DNA damage repair in these regions. Overall, our results indicate that tRNA genes are highly susceptible to ssDNA-specific DNA damaging agents. However, increased DNA repair efficacy in tRNA genes can prevent their hypermutation and maintain both genome and proteome homeostasis.
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Affiliation(s)
- Natalie Saini
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, NC, USA
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Joan F Sterling
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, NC, USA
| | - Ewa P Malc
- Department of Genetics,Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - Piotr A Mieczkowski
- Department of Genetics,Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - Dmitry A Gordenin
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, NC, USA.
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26
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Tripartite DNA Lesion Recognition and Verification by XPC, TFIIH, and XPA in Nucleotide Excision Repair. Mol Cell 2015; 59:1025-34. [PMID: 26384665 DOI: 10.1016/j.molcel.2015.08.012] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/09/2015] [Accepted: 08/17/2015] [Indexed: 11/23/2022]
Abstract
Transcription factor IIH (TFIIH) is essential for both transcription and nucleotide excision repair (NER). DNA lesions are initially detected by NER factors XPC and XPE or stalled RNA polymerases, but only bulky lesions are preferentially repaired by NER. To elucidate substrate specificity in NER, we have prepared homogeneous human ten-subunit TFIIH and its seven-subunit core (Core7) without the CAK module and show that bulky lesions in DNA inhibit the ATPase and helicase activities of both XPB and XPD in Core7 to promote NER, whereas non-genuine NER substrates have no such effect. Moreover, the NER factor XPA activates unwinding of normal DNA by Core7, but inhibits the Core7 helicase activity in the presence of bulky lesions. Finally, the CAK module inhibits DNA binding by TFIIH and thereby enhances XPC-dependent specific recruitment of TFIIH. Our results support a tripartite lesion verification mechanism involving XPC, TFIIH, and XPA for efficient NER.
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27
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Skoneczna A, Kaniak A, Skoneczny M. Genetic instability in budding and fission yeast-sources and mechanisms. FEMS Microbiol Rev 2015; 39:917-67. [PMID: 26109598 PMCID: PMC4608483 DOI: 10.1093/femsre/fuv028] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 12/17/2022] Open
Abstract
Cells are constantly confronted with endogenous and exogenous factors that affect their genomes. Eons of evolution have allowed the cellular mechanisms responsible for preserving the genome to adjust for achieving contradictory objectives: to maintain the genome unchanged and to acquire mutations that allow adaptation to environmental changes. One evolutionary mechanism that has been refined for survival is genetic variation. In this review, we describe the mechanisms responsible for two biological processes: genome maintenance and mutation tolerance involved in generations of genetic variations in mitotic cells of both Saccharomyces cerevisiae and Schizosaccharomyces pombe. These processes encompass mechanisms that ensure the fidelity of replication, DNA lesion sensing and DNA damage response pathways, as well as mechanisms that ensure precision in chromosome segregation during cell division. We discuss various factors that may influence genome stability, such as cellular ploidy, the phase of the cell cycle, transcriptional activity of a particular region of DNA, the proficiency of DNA quality control systems, the metabolic stage of the cell and its respiratory potential, and finally potential exposure to endogenous or environmental stress. The stability of budding and fission yeast genomes is influenced by two contradictory factors: (1) the need to be fully functional, which is ensured through the replication fidelity pathways of nuclear and mitochondrial genomes through sensing and repairing DNA damage, through precise chromosome segregation during cell division; and (2) the need to acquire changes for adaptation to environmental challenges.
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Affiliation(s)
- Adrianna Skoneczna
- Laboratory of Mutagenesis and DNA Repair, Institute of Biochemistry and Biophysics, Polish Academy of Science, 02-106 Warsaw, Poland
| | - Aneta Kaniak
- Laboratory of Mutagenesis and DNA Repair, Institute of Biochemistry and Biophysics, Polish Academy of Science, 02-106 Warsaw, Poland
| | - Marek Skoneczny
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Science, 02-106 Warsaw, Poland
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28
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Million-Weaver S, Samadpour AN, Moreno-Habel DA, Nugent P, Brittnacher MJ, Weiss E, Hayden HS, Miller SI, Liachko I, Merrikh H. An underlying mechanism for the increased mutagenesis of lagging-strand genes in Bacillus subtilis. Proc Natl Acad Sci U S A 2015; 112:E1096-105. [PMID: 25713353 PMCID: PMC4364195 DOI: 10.1073/pnas.1416651112] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We previously reported that lagging-strand genes accumulate mutations faster than those encoded on the leading strand in Bacillus subtilis. Although we proposed that orientation-specific encounters between replication and transcription underlie this phenomenon, the mechanism leading to the increased mutagenesis of lagging-strand genes remained unknown. Here, we report that the transcription-dependent and orientation-specific differences in mutation rates of genes require the B. subtilis Y-family polymerase, PolY1 (yqjH). We find that without PolY1, association of the replicative helicase, DnaC, and the recombination protein, RecA, with lagging-strand genes increases in a transcription-dependent manner. These data suggest that PolY1 promotes efficient replisome progression through lagging-strand genes, thereby reducing potentially detrimental breaks and single-stranded DNA at these loci. Y-family polymerases can alleviate potential obstacles to replisome progression by facilitating DNA lesion bypass, extension of D-loops, or excision repair. We find that the nucleotide excision repair (NER) proteins UvrA, UvrB, and UvrC, but not RecA, are required for transcription-dependent asymmetry in mutation rates of genes in the two orientations. Furthermore, we find that the transcription-coupling repair factor Mfd functions in the same pathway as PolY1 and is also required for increased mutagenesis of lagging-strand genes. Experimental and SNP analyses of B. subtilis genomes show mutational footprints consistent with these findings. We propose that the interplay between replication and transcription increases lesion susceptibility of, specifically, lagging-strand genes, activating an Mfd-dependent error-prone NER mechanism. We propose that this process, at least partially, underlies the accelerated evolution of lagging-strand genes.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Ivan Liachko
- Genome Sciences, University of Washington, Seattle, WA 98195
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29
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You C, Wang J, Dai X, Wang Y. Transcriptional inhibition and mutagenesis induced by N-nitroso compound-derived carboxymethylated thymidine adducts in DNA. Nucleic Acids Res 2015; 43:1012-8. [PMID: 25572317 PMCID: PMC4333421 DOI: 10.1093/nar/gku1391] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
N-nitroso compounds represent a common type of environmental and endogenous DNA-damaging agents. After metabolic activation, many N-nitroso compounds are converted into a diazoacetate intermediate that can react with nucleobases to give carboxymethylated DNA adducts such as N3-carboxymethylthymidine (N3-CMdT) and O4-carboxymethylthymidine (O4-CMdT). In this study, we constructed non-replicative plasmids carrying a single N3-CMdT or O4-CMdT, site-specifically positioned in the transcribed strand, to investigate how these lesions compromise the flow of genetic information during transcription. Our results revealed that both N3-CMdT and O4-CMdT substantially inhibited DNA transcription mediated by T7 RNA polymerase or human RNA polymerase II in vitro and in human cells. In addition, we found that N3-CMdT and O4-CMdT were miscoding lesions and predominantly directed the misinsertion of uridine and guanosine, respectively. Our results also suggested that these carboxymethylated thymidine lesions may constitute efficient substrates for transcription-coupled nucleotide excision repair in human cells. These findings provided important new insights into the biological consequences of the carboxymethylated DNA lesions in living cells.
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Affiliation(s)
- Changjun You
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | - Jianshuang Wang
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | - Xiaoxia Dai
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
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30
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Sakurai E, Susuki M, Kanamitsu K, Kawano S, Ikeda S. Global Genome Nucleotide Excision Repair Proteins Rhp7p and Rhp41p Are Involved in Abasic Site Repair of <i>Schizosaccharomyces pombe</i>. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/abb.2015.64026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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31
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You C, Wang P, Dai X, Wang Y. Transcriptional bypass of regioisomeric ethylated thymidine lesions by T7 RNA polymerase and human RNA polymerase II. Nucleic Acids Res 2014; 42:13706-13. [PMID: 25404131 PMCID: PMC4267633 DOI: 10.1093/nar/gku1183] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Alkylative damage to DNA can be induced by environmental chemicals, endogenous metabolites and some commonly prescribed chemotherapeutic agents. The regioisomeric N3-, O(2)- and O(4)-ethylthymidine (N3-, O(2)- and O(4)-EtdT, respectively) represent an important class of ethylated DNA lesions. Using nonreplicative double-stranded vectors containing an N3-EtdT, O(2)-EtdT or O(4)-EtdT at a defined site in the template strand, herein we examined the effects of these lesions on DNA transcription mediated by single-subunit T7 RNA polymerase or multisubunit human RNA polymerase II in vitro and in human cells. We found that O(4)-EtdT is highly mutagenic and exclusively induces the misincorporation of guanine opposite the lesion, whereas N3-EtdT and O(2)-EtdT display promiscuous miscoding properties during transcription. In addition, N3-EtdT and O(2)-EtdT were found to inhibit strongly DNA transcription in vitro and in certain human cells. Moreover, N3-EtdT, but not O(2)-EtdT or O(4)-EtdT, is an efficient substrate for transcription-coupled nucleotide excision repair. These findings provide new important insights into how these alkylated DNA lesions compromise the flow of genetic information, which may help to understand the risk of these lesions in living cells.
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Affiliation(s)
- Changjun You
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | - Pengcheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403, USA
| | - Xiaoxia Dai
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA 92521-0403, USA Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403, USA
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32
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Abstract
Transcription requires unwinding complementary DNA strands, generating torsional stress, and sensitizing the exposed single strands to chemical reactions and endogenous damaging agents. In addition, transcription can occur concomitantly with the other major DNA metabolic processes (replication, repair, and recombination), creating opportunities for either cooperation or conflict. Genetic modifications associated with transcription are a global issue in the small genomes of microorganisms in which noncoding sequences are rare. Transcription likewise becomes significant when one considers that most of the human genome is transcriptionally active. In this review, we focus specifically on the mutagenic consequences of transcription. Mechanisms of transcription-associated mutagenesis in microorganisms are discussed, as is the role of transcription in somatic instability of the vertebrate immune system.
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Affiliation(s)
- Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710;
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33
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Abstract
DNA repair mechanisms are critical for maintaining the integrity of genomic DNA, and their loss is associated with cancer predisposition syndromes. Studies in Saccharomyces cerevisiae have played a central role in elucidating the highly conserved mechanisms that promote eukaryotic genome stability. This review will focus on repair mechanisms that involve excision of a single strand from duplex DNA with the intact, complementary strand serving as a template to fill the resulting gap. These mechanisms are of two general types: those that remove damage from DNA and those that repair errors made during DNA synthesis. The major DNA-damage repair pathways are base excision repair and nucleotide excision repair, which, in the most simple terms, are distinguished by the extent of single-strand DNA removed together with the lesion. Mistakes made by DNA polymerases are corrected by the mismatch repair pathway, which also corrects mismatches generated when single strands of non-identical duplexes are exchanged during homologous recombination. In addition to the true repair pathways, the postreplication repair pathway allows lesions or structural aberrations that block replicative DNA polymerases to be tolerated. There are two bypass mechanisms: an error-free mechanism that involves a switch to an undamaged template for synthesis past the lesion and an error-prone mechanism that utilizes specialized translesion synthesis DNA polymerases to directly synthesize DNA across the lesion. A high level of functional redundancy exists among the pathways that deal with lesions, which minimizes the detrimental effects of endogenous and exogenous DNA damage.
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34
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Kim N, Cho JE, Li YC, Jinks-Robertson S. RNA∶DNA hybrids initiate quasi-palindrome-associated mutations in highly transcribed yeast DNA. PLoS Genet 2013; 9:e1003924. [PMID: 24244191 PMCID: PMC3820800 DOI: 10.1371/journal.pgen.1003924] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 09/05/2013] [Indexed: 11/18/2022] Open
Abstract
RNase H enzymes promote genetic stability by degrading aberrant RNA∶DNA hybrids and by removing ribonucleotide monophosphates (rNMPs) that are present in duplex DNA. Here, we report that loss of RNase H2 in yeast is associated with mutations that extend identity between the arms of imperfect inverted repeats (quasi-palindromes or QPs), a mutation type generally attributed to a template switch during DNA synthesis. QP events were detected using frameshift-reversion assays and were only observed under conditions of high transcription. In striking contrast to transcription-associated short deletions that also are detected by these assays, QP events do not require Top1 activity. QP mutation rates are strongly affected by the direction of DNA replication and, in contrast to their elevation in the absence of RNase H2, are reduced when RNase H1 is additionally eliminated. Finally, transcription-associated QP events are limited by components of the nucleotide excision repair pathway and are promoted by translesion synthesis DNA polymerases. We suggest that QP mutations reflect either a transcription-associated perturbation of Okazaki-fragment processing, or the use of a nascent transcript to resume replication following a transcription-replication conflict. Mutation rates are correlated with the level of gene expression in budding yeast, demonstrating a link between transcription and stability of the underlying DNA template. In the current work, we describe a novel type of transcription-associated mutation that converts imperfect inverted repeats (quasi-palindromes or QPs) to perfect inverted repeats. Using appropriate mutation reporters, we demonstrate that QP mutations are strongly affected by the direction of DNA replication and have distinctive genetic requirements. Most notably, rates of transcription-associated QP events are regulated by the RNase H class of enzymes, which are specialized to process the RNA component of RNA∶DNA hybrids. The source of the RNA∶DNA hybrids that initiate QP mutations is unclear, but could reflect transcripts that remain stably base-paired with the DNA template, or aberrant processing of the RNA primers normally used to initiate DNA synthesis. These studies further expand the diverse ways that transcription affects the mutation landscape, and establish a novel way that RNA∶DNA hybrids can contribute to genetic instability. The high conservation of basic DNA-related metabolic processes suggests that results in yeast will be broadly applicable in higher eukaryotes.
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Affiliation(s)
- Nayun Kim
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jang-Eun Cho
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Yue C. Li
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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35
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Brooks PJ. Blinded by the UV light: how the focus on transcription-coupled NER has distracted from understanding the mechanisms of Cockayne syndrome neurologic disease. DNA Repair (Amst) 2013; 12:656-71. [PMID: 23683874 PMCID: PMC4240003 DOI: 10.1016/j.dnarep.2013.04.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cockayne syndrome (CS) is a devastating neurodevelopmental disorder, with growth abnormalities, progeriod features, and sun sensitivity. CS is typically considered to be a DNA repair disorder, since cells from CS patients have a defect in transcription-coupled nucleotide excision repair (TC-NER). However, cells from UV-sensitive syndrome patients also lack TC-NER, but these patients do not suffer from the neurologic and other abnormalities that CS patients do. Also, the neurologic abnormalities that affect CS patients (CS neurologic disease) are qualitatively different from those seen in NER-deficient XP patients. Therefore, the TC-NER defect explains the sun sensitive phenotype common to both CS and UVsS, but cannot explain CS neurologic disease. However, as CS neurologic disease is of much greater clinical significance than the sun sensitivity, there is a pressing need to understand its molecular basis. While there is evidence for defective repair of oxidative DNA damage and mitochondrial abnormalities in CS cells, here I propose that the defects in transcription by both RNA polymerases I and II that have been documented in CS cells provide a better explanation for many of the severe growth and neurodevelopmental defects in CS patients than defective DNA repair. The implications of these ideas for interpreting results from mouse models of CS, and for the development of treatments and therapies for CS patients are discussed.
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Affiliation(s)
- P J Brooks
- Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, NIH, 5625 Fishers Lane, 3S-32, Bethesda, MD 20892, USA.
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36
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Budworth H, McMurray CT. Bidirectional transcription of trinucleotide repeats: roles for excision repair. DNA Repair (Amst) 2013; 12:672-84. [PMID: 23669397 DOI: 10.1016/j.dnarep.2013.04.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genomic instability at repetitive DNA regions in cells of the nervous system leads to a number of neurodegenerative and neuromuscular diseases, including those with an expanded trinucleotide repeat (TNR) tract at or nearby an expressed gene. Expansion causes disease when a particular base sequence is repeated beyond the normal range, interfering with the expression or properties of a gene product. Disease severity and onset depend on the number of repeats. As the length of the repeat tract grows, so does the size of the successive expansions and the likelihood of another unstable event. In fragile X syndrome, for example, CGG repeat instability and pathogenesis are not typically observed below tracts of roughly 50 repeats, but occur frequently at or above 55 repeats, and are virtually certain above 100-300 repeats. Recent evidence points to bidirectional transcription as a new aspect of TNR instability and pathophysiology. Bidirectional transcription of TNR genes produces novel proteins and/or regulatory RNAs that influence both toxicity and epigenetic changes in TNR promoters. Bidirectional transcription of the TNR tract appears to influence aspects of its stability, gene processing, splicing, gene silencing, and chemical modification of DNAs. Paradoxically, however, some of the same effects are observed on both the expanded TNR gene and on its normal gene counterpart. In this review, we discuss the possible normal and abnormal effects of bidirectional transcription on trinucleotide repeat instability, the role of DNA repair in causing, preventing, or maintaining methylation, and chromatin environment of TNR genes.
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Affiliation(s)
- Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Gaillard H, Herrera-Moyano E, Aguilera A. Transcription-associated genome instability. Chem Rev 2013; 113:8638-61. [PMID: 23597121 DOI: 10.1021/cr400017y] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla , Av. Américo Vespucio s/n, 41092 Seville, Spain
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Singh V, Das P. Condensation of DNA--a putative obstruction for repair process in abasic clustered DNA damage. DNA Repair (Amst) 2013; 12:450-7. [PMID: 23582211 DOI: 10.1016/j.dnarep.2013.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/27/2013] [Accepted: 03/07/2013] [Indexed: 12/31/2022]
Abstract
Clustered DNA damages are defined as two or more closely located DNA damage lesions that may be present within a few helical turns of the DNA double strand. These damages are potential signatures of ionizing radiation and are often found to be repair resistant. Types of damaged lesions frequently found inside clustered DNA damage sites include oxidized bases, abasic sites, nucleotide dimers, strand breaks or their complex combinations. In this study, we used a bistranded two-lesion abasic cluster DNA damage model to access the repair process of DNA in condensate form. Oligomer DNA duplexes (47 bp) were designed to have two deoxyuridine in the middle of the sequences, three bases apart in opposite strands. The deoxyuridine residues were converted into abasic sites by treatment with UDG enzyme creating an abasic clustered damage site in a precise position in each of the single strand of the DNA duplex. This oligomer duplex having compatible cohesive ends was ligated to pUC19 plasmid, linearized with HindIII restriction endonuclease. The plasmid-oligomer conjugate was transformed into condensates by treating them with spermidine. The efficiency of strand cleavage action of ApeI enzyme on the abasic sites was determined by denaturing PAGE after timed incubation of the oligomer duplex and the oligomer-plasmid conjugate in presence and absence of spermidine. The efficiency of double strand breaks was determined similarly by native PAGE. Quantitative gel analysis revealed that rate of abasic site cleavage is reduced in the DNA condensates as compared to the oligomer DNA duplex or the linear ligated oligomer-plasmid conjugates. Generation of double strand break is significantly reduced also, suggesting that their creation is not proportionate to the number of abasic sites cleaved in the condensate model. All these suggest that the ApeI enzyme have difficulty to access the abasic sites located deep into the condensates leading to repair refractivity of the damages. In addition, we found that presence of a polyamine such as spermidine has no notable effect in the incision activity of ApeI enzyme in linear oligomer DNA duplexes in our experimental concentration.
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Affiliation(s)
- Vandana Singh
- Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India.
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Khobta A, Epe B. Repair of oxidatively generated DNA damage in Cockayne syndrome. Mech Ageing Dev 2013; 134:253-60. [PMID: 23518175 DOI: 10.1016/j.mad.2013.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/12/2013] [Accepted: 03/01/2013] [Indexed: 11/16/2022]
Abstract
Defects in the repair of endogenously (especially oxidatively) generated DNA modifications and the resulting genetic instability can potentially explain the clinical symptoms of Cockayne syndrome (CS), a hereditary disease characterized by developmental defects and neurological degeneration. In this review, we describe the evidence for the involvement of CSA and CSB proteins, which are mutated in most of the CS patients, in the repair and processing of DNA damage induced by reactive oxygen species and the implications for the induction of cell death and mutations. Taken together, the data demonstrate that CSA and CSB, in addition to their established role in transcription-coupled nucleotide excision repair, can modulate the base excision repair (BER) of oxidized DNA bases both directly (by interaction with BER proteins) and indirectly (by modulating the expression of the DNA repair genes). Both nuclear and mitochondrial DNA repair is affected by mutations in CSA and CSB genes. However, the observed retardations of repair and the resulting accumulation of unrepaired endogenously generated DNA lesions are often mild, thus pointing to the relevance of additional roles of the CS proteins, e.g. in the mitochondrial response to oxidatively generated DNA damage and in the maintenance of gene transcription.
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Affiliation(s)
- Andriy Khobta
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55099 Mainz, Germany.
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Abedin Z, Louis-Juste M, Stangl M, Field J. The role of base excision repair genes OGG1, APN1 and APN2 in benzo[a]pyrene-7,8-dione induced p53 mutagenesis. Mutat Res 2013; 750:121-8. [PMID: 23117049 PMCID: PMC3931135 DOI: 10.1016/j.mrgentox.2012.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 10/17/2012] [Accepted: 10/18/2012] [Indexed: 12/17/2022]
Abstract
Lung cancer is primarily caused by exposure to tobacco smoke. Tobacco smoke contains numerous carcinogens, including polycyclic aromatic hydrocarbons (PAH). The most common PAH studied is benzo[a]pyrene (B[a]P). B[a]P is metabolically activated through multiple routes, one of which is catalyzed by aldo-keto reductase (AKR) to B[a]P-7,8-dione (BPQ). BPQ undergoes a futile redox cycle in the presence of NADPH to generate reactive oxygen species (ROS). ROS, in turn, damages DNA. Studies with a yeast p53 mutagenesis system found that the generation of ROS by PAH o-quinones may contribute to lung carcinogenesis because of similarities between the patterns (types of mutations) and spectra (location of mutations) and those seen in lung cancer. The patterns were dominated by G to T transversions, and the spectra in the experimental system have mutations at lung cancer hotspots. To address repair mechanisms that are responsible for BPQ induced damage we observed the effect of mutating two DNA repair genes OGG1 and APE1 (APN1 in yeast) and tested them in a yeast reporter system for p53 mutagenesis. There was an increase in both the mutant frequency and the number of G:C/T:A transversions in p53 treated with BPQ in ogg1 yeast but not in apn1 yeast. Knocking out APN2 increased mutagenesis in the apn1 cells. In addition, we did not find a strand bias on p53 treated with BPQ in ogg1 yeast. These studies suggest that Ogg1 is involved in repairing the oxidative damage caused by BPQ, Apn1 and Apn2 have redundant functions and that the stand bias seen in lung cancer may not be due to impaired repair of oxidative lesions.
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Affiliation(s)
- Zahidur Abedin
- Department of Pharmacology, Centers for Excellence in Environmental Toxicology and Cancer Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084, USA
| | - Melissa Louis-Juste
- Department of Pharmacology, Centers for Excellence in Environmental Toxicology and Cancer Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084, USA
| | - Melissa Stangl
- Department of Pharmacology, Centers for Excellence in Environmental Toxicology and Cancer Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084, USA
| | - Jeffrey Field
- Department of Pharmacology, Centers for Excellence in Environmental Toxicology and Cancer Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084, USA
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Alexander MP, Begins KJ, Crall WC, Holmes MP, Lippert MJ. High levels of transcription stimulate transversions at GC base pairs in yeast. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2013; 54:44-53. [PMID: 23055242 PMCID: PMC5013542 DOI: 10.1002/em.21740] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 08/18/2012] [Accepted: 08/22/2012] [Indexed: 06/01/2023]
Abstract
High-levels of transcription through a gene stimulate spontaneous mutation rate, a phenomenon termed transcription-associated mutation (TAM). While transcriptional effects on specific mutation classes have been identified using forward mutation and frameshift-reversion assays, little is yet known about transcription-associated base substitutions in yeast. To address this issue, we developed a new base substitution reversion assay (the lys2-TAG allele). We report a 22-fold increase in overall reversion rate in the high- relative to the low-transcription strain (from 2.1- to 47- × 10(-9) ). While all detectable base substitution types increased in the high-transcription strain, G→T and G→C transversions increased disproportionately by 58- and 52-fold, respectively. To assess a potential role of DNA damage in the TAM events, we measured mutation rates and spectra in individual strains defective in the repair of specific DNA lesions or null for the error-prone translesion DNA polymerase zeta (Pol zeta). Results exclude a role of 8-oxoGuanine, general oxidative damage, or apurinic/apyrimidinic sites in the generation of TAM G→T and G→C transversions. In contrast, the TAM transversions at GC base pairs depend on Pol zeta for occurrence implicating DNA damage, other than oxidative lesions or AP sites, in the TAM mechanism. Results further indicate that transcription-dependent G→T transversions in yeast differ mechanistically from equivalent events in E. coli reported by others. Given their occurrences in repair-proficient cells, transcription-associated G→T and G→C events represent a novel type of transcription-associated mutagenesis in normal cells with potentially important implications for evolution and genetic disease.
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Affiliation(s)
| | | | | | | | - Malcolm J. Lippert
- Correspondence to: Malcolm J. Lippert, Saint Michael's College, Biology Department, Box 283, 1 Winooski Park, Colchester, VT 05439, USA.
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Abstract
Alterations in genome sequence and structure contribute to somatic disease, affect the fitness of subsequent generations and drive evolutionary processes. The crucial roles of highly accurate replication and efficient repair in maintaining overall genome integrity are well-known, but the more localized stability costs that are associated with transcribing DNA into RNA molecules are less appreciated. Here we review the diverse ways in which the essential process of transcription alters the underlying DNA template and thereby modifies the genetic landscape.
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Collura A, Kemp PAVD, Boiteux S. Abasic sites linked to dUTP incorporation in DNA are a major cause of spontaneous mutations in absence of base excision repair and Rad17-Mec3-Ddc1 (9-1-1) DNA damage checkpoint clamp in Saccharomyces cerevisiae. DNA Repair (Amst) 2012; 11:294-303. [PMID: 22226374 DOI: 10.1016/j.dnarep.2011.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/21/2011] [Accepted: 12/09/2011] [Indexed: 12/28/2022]
Abstract
In Saccharomyces cerevisiae, inactivation of base excision repair (BER) AP endonucleases (Apn1p and Apn2p) results in constitutive phosphorylation of Rad53p and delay in cell cycle progression at the G2/M transition. These data led us to investigate genetic interactions between Apn1p, Apn2p and DNA damage checkpoint proteins. The results show that mec1 sml1, rad53 sml1 and rad9 is synthetic lethal with apn1 apn2. In contrast, apn1 apn2 rad17, apn1 apn2 ddc1 and apn1 apn2 rad24 triple mutants are viable, although they exhibit a strong Can(R) spontaneous mutator phenotype. In these strains, high Can(R) mutation rate is dependent upon functional uracil DNA N-glycosylase (Ung1p) and mutation spectra are dominated by AT to CG events. The results point to a role for Rad17-Mec3-Ddc1 (9-1-1) checkpoint clamp in the prevention of mutations caused by abasic (AP) sites linked to incorporation of dUTP into DNA followed by the excision of uracil by Ung1p. The antimutator role of the (9-1-1) clamp can either rely on its essential function in the induction of the DNA damage checkpoint or to another function that specifically impacts DNA repair and/or mutagenesis at AP sites. Here, we show that the abrogation of the DNA damage checkpoint is not sufficient to enhance spontaneous mutagenesis in the apn1 apn2 rad9 sml1 quadruple mutant. Spontaneous mutagenesis was also explored in strains deficient in the two major DNA N-glycosylases/AP-lyases (Ntg1p and Ntg2p). Indeed, apn1 apn2 ntg1 ntg2 exhibits a strong Ung1p-dependent Can(R) mutator phenotype with a spectrum enriched in AT to CG, like apn1 apn2 rad17. However, genetic analysis reveals that ntg1 ntg2 and rad17 are not epistatic for spontaneous mutagenesis in apn1 apn2. We conclude that under normal growth conditions, dUTP incorporation into DNA is a major source of AP sites that cause high genetic instability in the absence of BER factors (Apn1p, Apn2p, Ntg1p and Ntg2p) and Rad17-Mec3-Ddc1 (9-1-1) checkpoint clamp in yeast.
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Affiliation(s)
- Ada Collura
- CEA, iRCM, 18 route du Panorama, 92265 Fontenay aux Roses, France.
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Kanamitsu K, Ikeda S. Fission yeast homologs of human XPC and CSB, rhp41 and rhp26, are involved in transcription-coupled repair of methyl methanesulfonate-induced DNA damage. Genes Genet Syst 2011; 86:83-91. [PMID: 21670547 DOI: 10.1266/ggs.86.83] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Methyl methanesulfonate (MMS) methylates nitrogen atoms in purines, and predominantly produces 7-methylguanine and 3-methyladenine (3-meA). Previously, we showed that base excision repair (BER) and nucleotide excision repair (NER) synergistically function to repair MMS-induced DNA damage in the fission yeast Schizosaccharomyces pombe. Here, we studied the roles of NER components in repair of 3-meA and BER intermediates such as the AP site and single strand breaks. Mutants of rhp41 (XPC homolog) and rhp26 (CSB homolog) exhibited moderate sensitivity to MMS. Transcription of the fbp1 gene, which is induced by glucose starvation, was strongly inhibited by MMS damage in rhp41Δ and rhp26Δ strains but not in wild type and 3-meA DNA glycosylase-deficient cells. The results indicate that Rhp41p and Rhp26p are involved in transcription-coupled repair (TCR) of MMS-induced DNA damage. In the BER pathway of S. pombe, AP lyase activity of Nth1p mainly incises the AP site to generate a 3'-blocked end, which is in turn converted to 3'-OH by Apn2p. Deletion of rad16 or rhp26 in the nth1Δ strain greatly enhanced MMS sensitivity, suggesting that the AP site could also be corrected by TCR. Double mutant apn2Δ/rad16Δ exhibited hypersensitivity to MMS, implying that Rad16p provides a backup pathway for removal of the 3'-blocked end. Moreover, an rhp51Δ strain was extremely sensitive to MMS and double mutants of nth1Δ/rhp51Δ and apn2Δ/rhp51Δ increased the sensitivity, suggesting that homologous recombination is necessary for repair of three different types of lesions, 3-meA, AP sites and 3'-blocked ends.
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Affiliation(s)
- Kyoichiro Kanamitsu
- Department of Biochemistry, Faculty of Science, Okayama University of Science, Okayama 700-0005, Japan
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Kim N, Mudrak SV, Jinks-Robertson S. The dCMP transferase activity of yeast Rev1 is biologically relevant during the bypass of endogenously generated AP sites. DNA Repair (Amst) 2011; 10:1262-71. [PMID: 22024240 DOI: 10.1016/j.dnarep.2011.09.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/27/2011] [Accepted: 09/28/2011] [Indexed: 11/18/2022]
Abstract
The bypass of AP sites in yeast requires the Rev1 protein in addition to the Pol ζ translesion synthesis DNA polymerase. Although Rev1 was originally characterized biochemically as a dCMP transferase during AP-site bypass, the relevance of this activity in vivo is unclear. The current study uses highly sensitive frameshift- and nonsense-reversion assays to monitor the bypass of AP sites created when uracil is excised from chromosomal DNA. In the frameshift-reversion assay, an unselected base substitution frequently accompanies the selected mutation, allowing the relative incorporation of each of the four dNMPs opposite endogenously created AP sites to be inferred. Results with this assay suggest that dCMP is the most frequent dNMP inserted opposite uracil-derived AP sites and demonstrate that dCMP insertion absolutely requires the catalytic activity of Rev1. In the complementary nonsense-reversion assay, dCMP insertion likewise depended on the dCMP transferase activity of Rev1. Because dAMP insertion opposite uracil-derived AP sites does not revert the nonsense allele and hence could not be detected, it also was possible to detect low levels of dGMP or dTMP insertion upon loss of Rev1 catalytic activity. These results demonstrate that the catalytic activity of Rev1 is biologically relevant and is required specifically for dCMP insertion during the bypass of endogenous AP sites.
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Affiliation(s)
- Nayun Kim
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, United States
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Reis AMC, Mills WK, Ramachandran I, Friedberg EC, Thompson D, Queimado L. Targeted detection of in vivo endogenous DNA base damage reveals preferential base excision repair in the transcribed strand. Nucleic Acids Res 2011; 40:206-19. [PMID: 21911361 PMCID: PMC3245927 DOI: 10.1093/nar/gkr704] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Endogenous DNA damage is removed mainly via base excision repair (BER), however, whether there is preferential strand repair of endogenous DNA damage is still under intense debate. We developed a highly sensitive primer-anchored DNA damage detection assay (PADDA) to map and quantify in vivo endogenous DNA damage. Using PADDA, we documented significantly higher levels of endogenous damage in Saccharomyces cerevisiae cells in stationary phase than in exponential phase. We also documented that yeast BER-defective cells have significantly higher levels of endogenous DNA damage than isogenic wild-type cells at any phase of growth. PADDA provided detailed fingerprint analysis at the single-nucleotide level, documenting for the first time that persistent endogenous nucleotide damage in CAN1 co-localizes with previously reported spontaneous CAN1 mutations. To quickly and reliably quantify endogenous strand-specific DNA damage in the constitutively expressed CAN1 gene, we used PADDA on a real-time PCR setting. We demonstrate that wild-type cells repair endogenous damage preferentially on the CAN1 transcribed strand. In contrast, yeast BER-defective cells accumulate endogenous damage preferentially on the CAN1 transcribed strand. These data provide the first direct evidence for preferential strand repair of endogenous DNA damage and documents the major role of BER in this process.
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Affiliation(s)
- António M C Reis
- Department of Dermatology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Khobta A, Epe B. Interactions between DNA damage, repair, and transcription. Mutat Res 2011; 736:5-14. [PMID: 21907218 DOI: 10.1016/j.mrfmmm.2011.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 06/22/2011] [Accepted: 07/25/2011] [Indexed: 01/16/2023]
Abstract
This review addresses a variety of mechanisms by which DNA repair interacts with transcription and vice versa. Blocking of transcriptional elongation is the best studied of these mechanisms. Transcription recovery after damage therefore has often been used as a surrogate marker of DNA repair in cells. However, it has become evident that relationships between DNA damage, repair, and transcription are more complex due to various indirect effects of DNA damage on gene transcription. These include inhibition of transcription by DNA repair intermediates as well as regulation of transcription and of the epigenetic status of the genes by DNA repair-related mechanisms. In addition, since transcription is emerging as an important endogenous source of DNA damage in cells, we briefly summarise recent advances in understanding the nature of co-transcriptionally induced DNA damage and the DNA repair pathways involved.
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Affiliation(s)
- Andriy Khobta
- Institute of Pharmacy and Biochemistry, University of Mainz, Mainz, Germany
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Fuss JO, Tainer JA. XPB and XPD helicases in TFIIH orchestrate DNA duplex opening and damage verification to coordinate repair with transcription and cell cycle via CAK kinase. DNA Repair (Amst) 2011; 10:697-713. [PMID: 21571596 DOI: 10.1016/j.dnarep.2011.04.028] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Helicases must unwind DNA at the right place and time to maintain genomic integrity or gene expression. Biologically critical XPB and XPD helicases are key members of the human TFIIH complex; they anchor CAK kinase (cyclinH, MAT1, CDK7) to TFIIH and open DNA for transcription and for repair of duplex distorting damage by nucleotide excision repair (NER). NER is initiated by arrested RNA polymerase or damage recognition by XPC-RAD23B with or without DDB1/DDB2. XP helicases, named for their role in the extreme sun-mediated skin cancer predisposition xeroderma pigmentosum (XP), are then recruited to asymmetrically unwind dsDNA flanking the damage. XPB and XPD genetic defects can also cause premature aging with profound neurological defects without increased cancers: Cockayne syndrome (CS) and trichothiodystrophy (TTD). XP helicase patient phenotypes cannot be predicted from the mutation position along the linear gene sequence and adjacent mutations can cause different diseases. Here we consider the structural biology of DNA damage recognition by XPC-RAD23B, DDB1/DDB2, RNAPII, and ATL, and of helix unwinding by the XPB and XPD helicases plus the bacterial repair helicases UvrB and UvrD in complex with DNA. We then propose unified models for TFIIH assembly and roles in NER. Collective crystal structures with NMR and electron microscopy results reveal functional motifs, domains, and architectural elements that contribute to biological activities: damaged DNA binding, translocation, unwinding, and ATP driven changes plus TFIIH assembly and signaling. Coupled with mapping of patient mutations, these combined structural analyses provide a framework for integrating and unifying the rich biochemical and cellular information that has accumulated over forty years of study. This integration resolves puzzles regarding XP helicase functions and suggests that XP helicase positions and activities within TFIIH detect and verify damage, select the damaged strand for incision, and coordinate repair with transcription and cell cycle through CAK signaling.
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Affiliation(s)
- Jill O Fuss
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Kitsera N, Stathis D, Lühnsdorf B, Müller H, Carell T, Epe B, Khobta A. 8-Oxo-7,8-dihydroguanine in DNA does not constitute a barrier to transcription, but is converted into transcription-blocking damage by OGG1. Nucleic Acids Res 2011; 39:5926-34. [PMID: 21441539 PMCID: PMC3152326 DOI: 10.1093/nar/gkr163] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The common DNA base modification 8-oxo-7,8-dihydroguanine (8-oxo-G) affects the efficiency and fidelity of transcription. We constructed plasmid substrates carrying single 8-oxo-G residues, specifically positioned in the transcribed or the non-transcribed DNA strands, to investigate their effects on the expression of an EGFP reporter gene and to explore the role of base excision repair in the mechanism of transcription inhibition. We report that 8-oxo-G does not directly block transcription in cells, since a single 8-oxo-G in the transcribed DNA strand did not reduce the EGFP expression levels in repair-deficient (OGG1-null) mouse embryonic fibroblast cell lines. Rather, inhibition of transcription by 8-oxo-G fully depends on 8-oxoguanine DNA glycosylase (OGG1) and, at the same time, does not require the localization of the lesion in the transcribed DNA strand. We propose that the interruption of transcription is induced by base excision repair intermediates and, therefore, could be a common consequence of various DNA base modifications. Concordantly, the non-blocking DNA modification uracil was also found to inhibit transcription, but in an OGG1-independent manner.
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Affiliation(s)
- Nataliya Kitsera
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Staudingerweg 5, 55128 Mainz, Germany
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Khodyreva SN, Lavrik OI. Affinity modification in a proteomic study of DNA repair ensembles. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2011; 37:91-107. [DOI: 10.1134/s1068162011010109] [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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