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Yan Z, Wang D, Cai J, Shen L, Jiang M, Liu X, Huang J, Zhang Y, Luo E, Jing D. High-specificity protection against radiation-induced bone loss by a pulsed electromagnetic field. SCIENCE ADVANCES 2022; 8:eabq0222. [PMID: 36001662 PMCID: PMC9401628 DOI: 10.1126/sciadv.abq0222] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/11/2022] [Indexed: 05/28/2023]
Abstract
Radiotherapy increases tumor cure and survival rates; however, radiotherapy-induced bone damage remains a common issue for which effective countermeasures are lacking, especially considering tumor recurrence risks. We report a high-specificity protection technique based on noninvasive electromagnetic field (EMF). A unique pulsed-burst EMF (PEMF) at 15 Hz and 2 mT induces notable Ca2+ oscillations with robust Ca2+ spikes in osteoblasts in contrast to other waveforms. This waveform parameter substantially inhibits radiotherapy-induced bone loss by specifically modulating osteoblasts without affecting other bone cell types or tumor cells. Mechanistically, primary cilia are identified as major PEMF sensors in osteoblasts, and the differentiated ciliary expression dominates distinct PEMF sensitivity between osteoblasts and tumor cells. PEMF-induced unique Ca2+ oscillations depend on interactions between ciliary polycystins-1/2 and endoplasmic reticulum, which activates the Ras/MAPK/AP-1 axis and subsequent DNA repair Ku70 transcription. Our study introduces a previously unidentified method against radiation-induced bone damage in a noninvasive, cost-effective, and highly specific manner.
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Affiliation(s)
- Zedong Yan
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Dan Wang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Jing Cai
- College of Basic Medicine, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Liangliang Shen
- The State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi’an, China
| | - Maogang Jiang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Xiyu Liu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Jinghui Huang
- Institute of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Yong Zhang
- Department of Pulmonary and Critical Care of Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Erping Luo
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Da Jing
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
- The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, Fourth Military Medical University, Xi’an, China
- Shaanxi Provincial Key Laboratory of Bioelectromagnetic Detection and Intelligent Perception, Fourth Military Medical University, Xi’an, China
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Abstract
In mammalian cells, DNA double-strand breaks (DSBs) are mainly repaired by nonhomologous end joining (NHEJ) pathway. Ku (a heterodimer formed by Ku70 and Ku80 proteins) and DNA ligase IV are the core NHEJ factors. Ku could also be involved in other cellular processes, including telomere length regulation, DNA replication, transcription, and translation control. Leishmania, an early branching eukaryote and the causative agent of leishmaniasis, has no functional NHEJ pathway due to its lack of DNA ligase IV and other NHEJ factors but retains Ku70 and Ku80 proteins. In this study, we generated Leishmania donovani Ku70 disruption mutants and Ku70 and Ku80 double gene (Ku70/80) disruption mutants. We found that Leishmania Ku is still involved in DSB repair, possibly through its binding to DNA ends to block and slowdown 5′ end resections and Ku-Ku or other protein interactions. Depending on location of a DSB between the direct repeat genomic sequences, Leishmania Ku could have an inhibiting effect, no effect or a promoting effect on the DSB repair mediated by single strand annealing (SSA), the most frequently used DSB repair pathway in Leishmania. Ku70/80 proteins are also required for the healthy proliferation of Leishmania cells. Interestingly, unlike in Trypanosoma brucei and L. mexicana, Ku70/80 proteins are dispensable for maintaining the normal lengths of telomeres in L. donovani. We also show it is possible to reconstitute the two components (Ku and Ligase D) NHEJ pathway derived from Mycobacterium marinum in Leishmania. This improved DSB repair fidelity and efficiency in Leishmania and sets up an example that the bacterial NHEJ pathway can be successfully reconstructed in an NHEJ-deficient eukaryotic parasite. IMPORTANCE Nonhomologous end joining (NHEJ) is the most efficient double-stranded DNA break (DSB) repair pathway in mammalian cells. In contrast, the protozoan parasite Leishmania has no functional NHEJ pathway but retains the core NHEJ factors of Ku70 and Ku80 proteins. In this study, we found that Leishmania Ku heterodimers are still participating in DSB repair possibly through blocking 5′ end resections and Ku-Ku protein interactions. Depending on the DSB location, Ku could have an inhibiting or promoting effect on DSB repair mediated by the single-strand annealing repair pathway. Ku is also required for the normal growth of the parasite but surprisingly dispensable for maintaining the telomere lengths. Further, we show it is possible to introduce Mycobacterium marinum NHEJ pathway into Leishmania. Understanding DSB repair mechanisms of Leishmania may improve the CRISPR gene targeting specificity and efficiency and help identify new drug targets for this important human parasite.
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Saha J, Bae J, Wang SY, Lu H, Chappell LJ, Gopal P, Davis AJ. Ablating putative Ku70 phosphorylation sites results in defective DNA damage repair and spontaneous induction of hepatocellular carcinoma. Nucleic Acids Res 2021; 49:9836-9850. [PMID: 34428289 PMCID: PMC8464062 DOI: 10.1093/nar/gkab743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/31/2022] Open
Abstract
Multiple pathways mediate the repair of DNA double-strand breaks (DSBs), with numerous mechanisms responsible for driving choice between the pathways. Previously, we reported that mutating five putative phosphorylation sites on the non-homologous end joining (NHEJ) factor, Ku70, results in sustained retention of human Ku70/80 at DSB ends and attenuation of DSB repair via homologous recombination (HR). In this study, we generated a knock-in mouse, in which the three conserved putative phosphorylation sites of Ku70 were mutated to alanine to ablate potential phosphorylation (Ku703A/3A), in order to examine if disrupting DSB repair pathway choice by modulating Ku70/80 dynamics at DSB ends results in enhanced genomic instability and tumorigenesis. The Ku703A/3A mice developed spontaneous and have accelerated chemical-induced hepatocellular carcinoma (HCC) compared to wild-type (Ku70+/+) littermates. The HCC tumors from the Ku703A/3A mice have increased γH2AX and 8-oxo-G staining, suggesting decreased DNA repair. Spontaneous transformed cell lines from Ku703A/3A mice are more radiosensitive, have a significant decrease in DNA end resection, and are more sensitive to the DNA cross-linking agent mitomycin C compared to cells from Ku70+/+ littermates. Collectively, these findings demonstrate that mutating the putative Ku70 phosphorylation sites results in defective DNA damage repair and disruption of this process drives genomic instability and accelerated development of HCC.
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Affiliation(s)
- Janapriya Saha
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jinsung Bae
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Shih-Ya Wang
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Huiming Lu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Purva Gopal
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Anthony J Davis
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
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Kang YJ, Yan CT. Regulation of DNA repair in the absence of classical non-homologous end joining. DNA Repair (Amst) 2018; 68:34-40. [DOI: 10.1016/j.dnarep.2018.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 12/12/2022]
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Jung KB, Lee H, Son YS, Lee JH, Cho HS, Lee MO, Oh JH, Lee J, Kim S, Jung CR, Kim J, Son MY. In vitro and in vivo imaging and tracking of intestinal organoids from human induced pluripotent stem cells. FASEB J 2018; 32:111-122. [PMID: 28855280 DOI: 10.1096/fj.201700504r] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/14/2017] [Indexed: 12/16/2022]
Abstract
Human intestinal organoids (hIOs) derived from human pluripotent stem cells (hPSCs) have immense potential as a source of intestines. Therefore, an efficient system is needed for visualizing the stage of intestinal differentiation and further identifying hIOs derived from hPSCs. Here, 2 fluorescent biosensors were developed based on human induced pluripotent stem cell (hiPSC) lines that stably expressed fluorescent reporters driven by intestine-specific gene promoters Krüppel-like factor 5 monomeric Cherry (KLF5mCherry) and intestine-specific homeobox enhanced green fluorescence protein (ISXeGFP). Then hIOs were efficiently induced from those transgenic hiPSC lines in which mCherry- or eGFP-expressing cells, which appeared during differentiation, could be identified in intact living cells in real time. Reporter gene expression had no adverse effects on differentiation into hIOs and proliferation. Using our reporter system to screen for hIO differentiation factors, we identified DMH1 as an efficient substitute for Noggin. Transplanted hIOs under the kidney capsule were tracked with fluorescence imaging (FLI) and confirmed histologically. After orthotopic transplantation, the localization of the hIOs in the small intestine could be accurately visualized using FLI. Our study establishes a selective system for monitoring the in vitro differentiation and for tracking the in vivo localization of hIOs and contributes to further improvement of cell-based therapies and preclinical screenings in the intestinal field.-Jung, K. B., Lee, H., Son, Y. S., Lee, J. H., Cho, H.-S., Lee, M.-O., Oh, J.-H., Lee, J., Kim, S., Jung, C.-R., Kim, J., Son, M.-Y. In vitro and in vivo imaging and tracking of intestinal organoids from human induced pluripotent stem cells.
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Affiliation(s)
- Kwang Bo Jung
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Hana Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Ye Seul Son
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Ji Hye Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Hyun-Soo Cho
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Mi-Ok Lee
- Immunotherapy Covergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Jung-Hwa Oh
- Korea Institute of Toxicology, Daejeon, South Korea; and
| | - Jaemin Lee
- Aging Research Institute, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Seokho Kim
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
- Aging Research Institute, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Cho-Rok Jung
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea,
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Mi-Young Son
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea,
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
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Ignatov A, Bondarenko K, Makarova A. Non-bulky Lesions in Human DNA: the Ways of Formation, Repair, and Replication. Acta Naturae 2017; 9:12-26. [PMID: 29104772 PMCID: PMC5662270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Indexed: 11/06/2022] Open
Abstract
DNA damage is a major cause of replication interruption, mutations, and cell death. DNA damage is removed by several types of repair processes. The involvement of specialized DNA polymerases in replication provides an important mechanism that helps tolerate persistent DNA damage. Specialized DNA polymerases incorporate nucleotides opposite lesions with high efficiency but demonstrate low accuracy of DNA synthesis. In this review, we summarize the types and mechanisms of formation and repair of non-bulky DNA lesions, and we provide an overview of the role of specialized DNA polymerases in translesion DNA synthesis.
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Affiliation(s)
- A.V. Ignatov
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, Moscow, 123182 , Russia
- Department of Molecular Biology, Faculty of Biology, Moscow State University, Leninskie Gory 1, bldg. 12, Moscow, 119991, Russia
| | - K.A. Bondarenko
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, Moscow, 123182 , Russia
| | - A.V. Makarova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, Moscow, 123182 , Russia
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Physiological functions of programmed DNA breaks in signal-induced transcription. Nat Rev Mol Cell Biol 2017; 18:471-476. [PMID: 28537575 DOI: 10.1038/nrm.2017.43] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The idea that signal-dependent transcription might involve the generation of transient DNA nicks or even breaks in the regulatory regions of genes, accompanied by activation of DNA damage repair pathways, would seem to be counterintuitive, as DNA damage is usually considered harmful to cellular integrity. However, recent studies have generated a substantial body of evidence that now argues that programmed DNA single- or double-strand breaks can, at least in specific cases, have a role in transcription regulation. Here, we discuss the emerging functions of DNA breaks in the relief of DNA torsional stress and in promoter and enhancer activation.
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Anisenko AN, Knyazhanskaya ES, Zatsepin TS, Gottikh MB. Human Ku70 protein binds hairpin RNA and double stranded DNA through two different sites. Biochimie 2016; 132:85-93. [PMID: 27825805 DOI: 10.1016/j.biochi.2016.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 11/02/2016] [Indexed: 02/07/2023]
Abstract
Human protein Ku usually functions in the cell as a complex of two subunits, Ku70 and Ku80. The Ku heterodimer plays a key role in the non-homologous end joining DNA repair pathway by specifically recognizing the DNA ends at the site of the lesion. The binding of the Ku heterodimer to DNA has been well-studied, and its interactions with RNA have been also described. However, Ku70 subunit is known to have independent DNA binding capability, which is less characterized. RNA binding properties of Ku70 have not been yet specially studied. We have prepared recombinant full-length Ku70 and a set of its truncated mutants in E. coli, and studied their interactions with nucleic acids of various structures: linear single- and double-stranded DNA and RNA, as well as closed circular DNA and hairpin RNA. Ku70 has demonstrated a high affinity binding to double stranded DNA and hairpin RNA with a certain structure only. Interestingly, in contrast to the Ku heterodimer, Ku70 is found to interact with closed circular DNA. We also show for the first time that Ku70 employs two different sites for DNA and RNA binding. The double-stranded DNA is recognized by the C-terminal part of Ku70 including SAP domain as it has been earlier demonstrated, whereas hairpin RNA binding is provided by amino acids 251-438.
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Affiliation(s)
- Andrey N Anisenko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia.
| | | | - Timofey S Zatsepin
- Chemistry Department, Lomonosov Moscow State University, Moscow, Russia; Skolkovo Institute of Science and Technology, Skolkovo, Russia.
| | - Marina B Gottikh
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
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Gassman NR, Coskun E, Jaruga P, Dizdaroglu M, Wilson SH. Combined Effects of High-Dose Bisphenol A and Oxidizing Agent (KBrO3) on Cellular Microenvironment, Gene Expression, and Chromatin Structure of Ku70-deficient Mouse Embryonic Fibroblasts. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1241-52. [PMID: 27082013 PMCID: PMC4977032 DOI: 10.1289/ehp237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/26/2015] [Accepted: 03/28/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Exposure to bisphenol A (BPA) has been reported to alter global gene expression, induce epigenetic modifications, and interfere with complex regulatory networks of cells. In addition to these reprogramming events, we have demonstrated that BPA exposure generates reactive oxygen species and promotes cellular survival when co-exposed with the oxidizing agent potassium bromate (KBrO3). OBJECTIVES We determined the cellular microenvironment changes induced by co-exposure of BPA and KBrO3 versus either agent alone. METHODS Ku70-deficient cells were exposed to 150 μM BPA, 20 mM KBrO3, or co-exposed to both agents. Four and 24 hr post-damage initiation by KBrO3, with BPA-only samples timed to coincide with these designated time points, we performed whole-genome microarray analysis and evaluated chromatin structure, DNA lesion load, glutathione content, and intracellular pH. RESULTS We found that 4 hr post-damage initiation, BPA exposure and co-exposure transiently condensed chromatin compared with untreated and KBrO3-only treated cells; the transcription of DNA repair proteins was also reduced. At this time point, BPA exposure and co-exposure also reduced the change in intracellular pH observed after treatment with KBrO3 alone. Twenty-four hours post-damage initiation, BPA-exposed cells showed less condensed chromatin than cells treated with KBrO3 alone; the intracellular pH of the co-exposed cells was significantly reduced compared with untreated and KBrO3-treated cells; and significant up-regulation of DNA repair proteins was observed after co-exposure. CONCLUSION These results support the induction of an adaptive response by BPA co-exposure that alters the microcellular environment and modulates DNA repair. Further work is required to determine whether BPA induces similar DNA lesions in vivo at environmentally relevant doses; however, in the Ku70-deficient mouse embryonic fibroblasts, exposure to a high dose of BPA was associated with changes in the cellular microenvironment that may promote survival. CITATION Gassman NR, Coskun E, Jaruga P, Dizdaroglu M, Wilson SH. 2016. Combined effects of high-dose bisphenol A and oxidizing agent (KBrO3) on cellular microenvironment, gene expression, and chromatin structure of Ku70-deficient mouse embryonic fibroblasts. Environ Health Perspect 124:1241-1252; http://dx.doi.org/10.1289/EHP237.
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Affiliation(s)
- Natalie R. Gassman
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Erdem Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
- Faculty of Pharmacy, Gazi University, Ankara, Turkey
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Samuel H. Wilson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
- Address correspondence to S.H. Wilson, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, Research Triangle Park, NC 27709-12233 USA. Telephone: (919) 541-4701. E-mail:
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Kosova AA, Khodyreva SN, Lavrik OI. Ku antigen displays the AP lyase activity on a certain type of duplex DNA. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1244-1252. [PMID: 27129632 DOI: 10.1016/j.bbapap.2016.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/25/2016] [Accepted: 04/22/2016] [Indexed: 12/11/2022]
Abstract
In the search for proteins reactive to apurinic/apyrimidinic (AP) sites, it has been earlier found that proteins of human cell extracts formed the Schiff-base-dependent covalent adduct with an apparent molecular mass of 100kDa with a partial DNA duplex containing an AP site and 5'- and 3'-protruding ends (DDE-AP DNA). The adduct of such electrophoretic mobility was characteristic of only DDE-AP DNA (Ilina et al., Biochem. Biophys. Acta 1784 (2008) 1777-1785). The protein in this unusual adduct was identified as the Ku80 subunit of Ku antigen by peptide mass mapping based on MALDI-TOF MS data (Kosova et al., Biopolym. Cell 30 (2014) 42-46). Here we studied the interaction of Ku with DDE-AP DNA in details. Purified Ku (the Ku80 subunit) was shown to form the 100-kDa adduct highly specific for AP DNA with a certain length of protruding ends, base opposite the AP site and AP site location. Ku is capable of AP site cleavage in DDE-AP DNA unlike in analogous AP DNA with blunt ends. Ku cleaves AP sites via β-elimination and prefers apurinic sites over apyrimidinic ones. The AP site in DDE-DNA can be repaired in an apurinic/apyrimidinic endonuclease-independent manner via the successive action of Ku (cleavage of the AP site), tyrosyl-DNA phosphodiesterase 1 (removal of the 3'-deoxyribose residue), polynucleotide kinase 3'-phosphatase (removal of the 3'-phosphate), DNA polymerase β (incorporation of dNMP), and DNA ligase (sealing the nick). These results provide a new insight into the role of Ku in the repair of AP sites.
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Affiliation(s)
- Anastasiya A Kosova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Svetlana N Khodyreva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia; Novosibirsk State University, Novosibirsk, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia; Novosibirsk State University, Novosibirsk, Russia.
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de Ory A, Nagler K, Carrasco B, Raguse M, Zafra O, Moeller R, de Vega M. Identification of a conserved 5'-dRP lyase activity in bacterial DNA repair ligase D and its potential role in base excision repair. Nucleic Acids Res 2016; 44:1833-44. [PMID: 26826709 PMCID: PMC4770248 DOI: 10.1093/nar/gkw054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 11/14/2022] Open
Abstract
Bacillus subtilis is one of the bacterial members provided with a nonhomologous end joining (NHEJ) system constituted by the DNA-binding Ku homodimer that recruits the ATP-dependent DNA Ligase D (BsuLigD) to the double-stranded DNA breaks (DSBs) ends. BsuLigD has inherent polymerization and ligase activities that allow it to fill the short gaps that can arise after realignment of the broken ends and to seal the resulting nicks, contributing to genome stability during the stationary phase and germination of spores. Here we show that BsuLigD also has an intrinsic 5'-2-deoxyribose-5-phosphate (dRP) lyase activity located at the N-terminal ligase domain that in coordination with the polymerization and ligase activities allows efficient repairing of 2'-deoxyuridine-containing DNA in an in vitro reconstituted Base Excision Repair (BER) reaction. The requirement of a polymerization, a dRP removal and a final sealing step in BER, together with the joint participation of BsuLigD with the spore specific AP endonuclease in conferring spore resistance to ultrahigh vacuum desiccation suggest that BsuLigD could actively participate in this pathway. We demonstrate the presence of the dRP lyase activity also in the homolog protein from the distantly related bacterium Pseudomonas aeruginosa, allowing us to expand our results to other bacterial LigDs.
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Affiliation(s)
- Ana de Ory
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Katja Nagler
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Linder Hoehe, D-51147 Cologne, Germany
| | - Begoña Carrasco
- Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Científicas), Darwin 3, 28049 Madrid, Spain
| | - Marina Raguse
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Linder Hoehe, D-51147 Cologne, Germany
| | - Olga Zafra
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Ralf Moeller
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Linder Hoehe, D-51147 Cologne, Germany
| | - Miguel de Vega
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Nicolás Cabrera 1, 28049 Madrid, Spain
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Koike M, Yutoku Y, Koike A. Nuclear localization of mouse Ku70 in interphase cells and focus formation of mouse Ku70 at DNA damage sites immediately after irradiation. J Vet Med Sci 2015; 77:1137-42. [PMID: 25947323 PMCID: PMC4591156 DOI: 10.1292/jvms.14-0651] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To elucidate the mechanisms of DNA repair pathway is critical for developing next-generation radiotherapies and chemotherapeutic drugs for cancer. Ionizing radiation and many chemotherapeutic drugs kill tumor cells mainly by inducing DNA double-strand breaks (DSBs). The classical nonhomologous DNA-end joining (NHEJ) (C-NHEJ) pathway repairs a predominant fraction of DSBs in mammalian cells. The C-NHEJ pathway appears to start with the binding of Ku (heterodimer of Ku70 and Ku80) to DNA break ends. Therefore, recruitment of Ku to DSB sites might play a critical role in regulating NHEJ activity. Indeed, human Ku70 and Ku80 localize in the nuclei and accumulate at microirradiated DSB sites. However, the localization and regulation mechanisms of Ku70 and Ku80 homologues in animal models, such as mice and other species, have not been elucidated in detail, particularly in cells immediately after microirradiation. Here, we show that EYFP-tagged mouse Ku70 localizes in the interphase nuclei of mouse fibroblasts and epithelial cells. Furthermore, our findings indicate that EYFP-mouse Ku70 accumulates with its heterodimeric partner Ku80 immediately at laser-microirradiated DSB sites. We also confirmed that the structure of Ku70 nuclear localization signal (NLS) is highly conserved among various rodent species, such as the mouse, rat, degu and ground squirrel, supporting the idea that NLS is important for the regulation of rodent Ku70 function. Collectively, these results suggest that the mechanisms of regulating the localization and accumulation of Ku70 at DSBs might be well conserved between the mouse and human species.
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Affiliation(s)
- Manabu Koike
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Bisphenol a promotes cell survival following oxidative DNA damage in mouse fibroblasts. PLoS One 2015; 10:e0118819. [PMID: 25693136 PMCID: PMC4334494 DOI: 10.1371/journal.pone.0118819] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/16/2015] [Indexed: 12/02/2022] Open
Abstract
Bisphenol A (BPA) is a biologically active industrial chemical used in production of consumer products. BPA has become a target of intense public scrutiny following concerns about its association with human diseases such as obesity, diabetes, reproductive disorders, and cancer. Recent studies link BPA with the generation of reactive oxygen species, and base excision repair (BER) is responsible for removing oxidatively induced DNA lesions. Yet, the relationship between BPA and BER has yet to be examined. Further, the ubiquitous nature of BPA allows continuous exposure of the human genome concurrent with the normal endogenous and exogenous insults to the genome, and this co-exposure may impact the DNA damage response and repair. To determine the effect of BPA exposure on base excision repair of oxidatively induced DNA damage, cells compromised in double-strand break repair were treated with BPA alone or co-exposed with either potassium bromate (KBrO3) or laser irradiation as oxidative damaging agents. In experiments with KBrO3, co-treatment with BPA partially reversed the KBrO3-induced cytotoxicity observed in these cells, and this was coincident with an increase in guanine base lesions in genomic DNA. The improvement in cell survival and the increase in oxidatively induced DNA base lesions were reminiscent of previous results with alkyl adenine DNA glycosylase-deficient cells, suggesting that BPA may prevent initiation of repair of oxidized base lesions. With laser irradiation-induced DNA damage, treatment with BPA suppressed DNA repair as revealed by several indicators. These results are consistent with the hypothesis that BPA can induce a suppression of oxidized base lesion DNA repair by the base excision repair pathway.
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Kosova AA, Lavrik OI, Khodyreva SN. Role of Ku antigen in the repair of apurinic/apyrimidinic sites in DNA. Mol Biol 2015. [DOI: 10.1134/s0026893315010070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Puc J, Kozbial P, Li W, Tan Y, Liu Z, Suter T, Ohgi KA, Zhang J, Aggarwal AK, Rosenfeld MG. Ligand-dependent enhancer activation regulated by topoisomerase-I activity. Cell 2015; 160:367-80. [PMID: 25619691 DOI: 10.1016/j.cell.2014.12.023] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/28/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
Abstract
The discovery that enhancers are regulated transcription units, encoding eRNAs, has raised new questions about the mechanisms of their activation. Here, we report an unexpected molecular mechanism that underlies ligand-dependent enhancer activation, based on DNA nicking to relieve torsional stress from eRNA synthesis. Using dihydrotestosterone (DHT)-induced binding of androgen receptor (AR) to prostate cancer cell enhancers as a model, we show rapid recruitment, within minutes, of DNA topoisomerase I (TOP1) to a large cohort of AR-regulated enhancers. Furthermore, we show that the DNA nicking activity of TOP1 is a prerequisite for robust eRNA synthesis and enhancer activation and is kinetically accompanied by the recruitment of ATR and the MRN complex, followed by additional components of DNA damage repair machinery to the AR-regulated enhancers. Together, our studies reveal a linkage between eRNA synthesis and ligand-dependent TOP1-mediated nicking-a strategy exerting quantitative effects on eRNA expression in regulating AR-bound enhancer-dependent transcriptional programs.
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Affiliation(s)
- Janusz Puc
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Piotr Kozbial
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Wenbo Li
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Yuliang Tan
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Zhijie Liu
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Tom Suter
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA; Division of Biological Sciences, Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Kenneth A Ohgi
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Jie Zhang
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Aneel K Aggarwal
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA.
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The Ku heterodimer: function in DNA repair and beyond. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:15-29. [PMID: 25795113 DOI: 10.1016/j.mrrev.2014.06.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/07/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023]
Abstract
Ku is an abundant, highly conserved DNA binding protein found in both prokaryotes and eukaryotes that plays essential roles in the maintenance of genome integrity. In eukaryotes, Ku is a heterodimer comprised of two subunits, Ku70 and Ku80, that is best characterized for its central role as the initial DNA end binding factor in the "classical" non-homologous end joining (C-NHEJ) pathway, the main DNA double-strand break (DSB) repair pathway in mammals. Ku binds double-stranded DNA ends with high affinity in a sequence-independent manner through a central ring formed by the intertwined strands of the Ku70 and Ku80 subunits. At the break, Ku directly and indirectly interacts with several C-NHEJ factors and processing enzymes, serving as the scaffold for the entire DNA repair complex. There is also evidence that Ku is involved in signaling to the DNA damage response (DDR) machinery to modulate the activation of cell cycle checkpoints and the activation of apoptosis. Interestingly, Ku is also associated with telomeres, where, paradoxically to its DNA end-joining functions, it protects the telomere ends from being recognized as DSBs, thereby preventing their recombination and degradation. Ku, together with the silent information regulator (Sir) complex is also required for transcriptional silencing through telomere position effect (TPE). How Ku associates with telomeres, whether it is through direct DNA binding, or through protein-protein interactions with other telomere bound factors remains to be determined. Ku is central to the protection of organisms through its participation in C-NHEJ to repair DSBs generated during V(D)J recombination, a process that is indispensable for the establishment of the immune response. Ku also functions to prevent tumorigenesis and senescence since Ku-deficient mice show increased cancer incidence and early onset of aging. Overall, Ku function is critical to the maintenance of genomic integrity and to proper cellular and organismal development.
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The progeroid phenotype of Ku80 deficiency is dominant over DNA-PKCS deficiency. PLoS One 2014; 9:e93568. [PMID: 24740260 PMCID: PMC3989187 DOI: 10.1371/journal.pone.0093568] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 03/05/2014] [Indexed: 01/01/2023] Open
Abstract
Ku80 and DNA-PKCS are both involved in the repair of double strand DNA breaks via the nonhomologous end joining (NHEJ) pathway. While ku80-/- mice exhibit a severely reduced lifespan and size, this phenotype is less pronounced in dna-pkcs-/- mice. However, these observations are based on independent studies with varying genetic backgrounds. Here, we generated ku80-/-, dna-pkcs-/- and double knock out mice in a C57Bl6/J*FVB F1 hybrid background and compared their lifespan, end of life pathology and mutation frequency in liver and spleen using a lacZ reporter. Our data confirm that inactivation of Ku80 and DNA-PKCS causes reduced lifespan and bodyweights, which is most severe in ku80-/- mice. All mutant mice exhibited a strong increase in lymphoma incidence as well as other aging-related pathology (skin epidermal and adnexal atrophy, trabacular bone reduction, kidney tubular anisokaryosis, and cortical and medullar atrophy) and severe lymphoid depletion. LacZ mutation frequency analysis did not show strong differences in mutation frequencies between knock out and wild type mice. The ku80-/- mice had the most severe phenotype and the Ku80-mutation was dominant over the DNA-PKCS-mutation. Presumably, the more severe degenerative effect of Ku80 inactivation on lifespan compared to DNA-PKCS inactivation is caused by additional functions of Ku80 or activity of free Ku70 since both Ku80 and DNA-PKCS are essential for NHEJ.
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