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Rose JC, Wong ITL, Daniel B, Jones MG, Yost KE, Hung KL, Curtis EJ, Mischel PS, Chang HY. Disparate pathways for extrachromosomal DNA biogenesis and genomic DNA repair. bioRxiv 2023:2023.10.22.563489. [PMID: 37961138 PMCID: PMC10634728 DOI: 10.1101/2023.10.22.563489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Oncogene amplification on extrachromosomal DNA (ecDNA) is a pervasive driver event in cancer, yet our understanding of how ecDNA forms is limited. Here, we couple a CRISPR-based method for induction of ecDNA with extensive characterization of newly formed ecDNA to examine ecDNA biogenesis. We find that DNA circularization is efficient, irrespective of 3D genome context, with formation of a 1 Mb and 1.8 Mb ecDNA both reaching 15%. We show non-homologous end joining and microhomology mediated end joining both contribute to ecDNA formation, while inhibition of DNA-PKcs and ATM have opposing impacts on ecDNA formation. EcDNA and the corresponding chromosomal excision scar form at significantly different rates and respond differently to DNA-PKcs and ATM inhibition. Taken together, our results support a model of ecDNA formation in which double strand break ends dissociate from their legitimate ligation partners prior to joining of illegitimate ends to form the ecDNA and excision scar.
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Affiliation(s)
- John C Rose
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Ivy Tsz-Lo Wong
- Sarafan ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Bence Daniel
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Matthew G Jones
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Kathryn E Yost
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - King L Hung
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Ellis J Curtis
- Sarafan ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Paul S Mischel
- Sarafan ChEM-H, Stanford University, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford, CA, USA
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2
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Meschichi A, Zhao L, Reeck S, White C, Da Ines O, Sicard A, Pontvianne F, Rosa S. The plant-specific DDR factor SOG1 increases chromatin mobility in response to DNA damage. EMBO Rep 2022; 23:e54736. [PMID: 36278395 PMCID: PMC9724665 DOI: 10.15252/embr.202254736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 12/12/2022] Open
Abstract
Homologous recombination (HR) is a conservative DNA repair pathway in which intact homologous sequences are used as a template for repair. How the homology search happens in the crowded space of the cell nucleus is, however, still poorly understood. Here, we measure chromosome and double-strand break (DSB) site mobility in Arabidopsis thaliana, using lacO/LacI lines and two GFP-tagged HR reporters. We observe an increase in chromatin mobility upon the induction of DNA damage, specifically at the S/G2 phases of the cell cycle. This increase in mobility is lost in the sog1-1 mutant, a central transcription factor of the DNA damage response in plants. Also, DSB sites show particularly high mobility levels and their enhanced mobility requires the HR factor RAD54. Our data suggest that repair mechanisms promote chromatin mobility upon DNA damage, implying a role of this process in the early steps of the DNA damage response.
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Affiliation(s)
- Anis Meschichi
- Plant Biology DepartmentSwedish University of Agricultural SciencesUppsalaSweden
| | - Lihua Zhao
- Plant Biology DepartmentSwedish University of Agricultural SciencesUppsalaSweden
| | - Svenja Reeck
- John Innes Centre, Norwich Research ParkNorwichUK
| | - Charles White
- Institut Génétique Reproduction et Développement (iGReD)Université Clermont Auvergne, UMR 6293, CNRS, U1103 INSERMClermont‐FerrandFrance
| | - Olivier Da Ines
- Institut Génétique Reproduction et Développement (iGReD)Université Clermont Auvergne, UMR 6293, CNRS, U1103 INSERMClermont‐FerrandFrance
| | - Adrien Sicard
- Plant Biology DepartmentSwedish University of Agricultural SciencesUppsalaSweden
| | - Frédéric Pontvianne
- CNRS, Laboratoire Génome et Développement des Plantes (LGDP)Université de Perpignan Via DomitiaPerpignanFrance
| | - Stefanie Rosa
- Plant Biology DepartmentSwedish University of Agricultural SciencesUppsalaSweden
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3
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Cisneros-Aguirre M, Ping X, Stark JM. To indel or not to indel: Factors influencing mutagenesis during chromosomal break end joining. DNA Repair (Amst) 2022; 118:103380. [PMID: 35926296 PMCID: PMC10105512 DOI: 10.1016/j.dnarep.2022.103380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 12/16/2022]
Abstract
Chromosomal DNA double-strand breaks (DSBs) are the effective lesion of radiotherapy and other clastogenic cancer therapeutics, and are also the initiating event of many approaches to gene editing. Ligation of the DSBs by end joining (EJ) pathways can restore the broken chromosome, but the repair junctions can have insertion/deletion (indel) mutations. The indel patterns resulting from DSB EJ are likely defined by the initial structure of the DNA ends, how the ends are processed and synapsed prior to ligation, and the factors that mediate the ligation step. In this review, we describe key factors that influence these steps of DSB EJ in mammalian cells, which is significant both for understanding mutagenesis resulting from clastogenic cancer therapeutics, and for developing approaches to manipulating gene editing outcomes.
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Affiliation(s)
- Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Xiaoli Ping
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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4
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Meador JA, Balajee AS. Analysis of ionizing radiation induced DNA damage response in human adult stem cells and differentiated neurons. Mutat Res Genet Toxicol Environ Mutagen 2022; 878:503486. [PMID: 35649680 DOI: 10.1016/j.mrgentox.2022.503486] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 04/10/2022] [Accepted: 04/14/2022] [Indexed: 06/15/2023]
Abstract
Findings of neurodegenerative features associated with human radiosensitive syndromes such as Ataxia telangiectasia suggest that DNA repair efficiency is crucial for maintaining the functional integrity of central nervous system. To gain a better understanding of ionizing radiation (IR) induced DNA damage response in undifferentiated and differentiated neural cell types and to evaluate the role of ATM in DNA double strand break (DSB) repair, an in vitro human neural cell differentiation model system was utilized in this study. As compared to adult stem cells, differentiated neurons displayed an attenuated DSB repair response (as judged by the persistence of 53BP1 foci) after IR exposure and the attenuation was even more pronounced in stem cells and neurons after suppression of ATM (Ataxia Telangiectasia Mutated) gene product suggesting the importance of ATM for an optimal DSB repair efficiency in human neural cell types. In corroboration with an attenuated DNA damage response, a sharp decline in the expression levels of several DSB repair genes was observed in neurons. Our results suggest that cellular differentiation modulates the expression of several genes thereby compromising the DSB repair fidelity in post mitotic neurons. Further studies are required to verify whether or not ATM mediated exacerbation of DNA repair deficiency in differentiated neurons leads to neurodegeneration.
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Affiliation(s)
| | - Adayabalam S Balajee
- Cytogenetic Biodosimetry Laboratory, Radiation Emergency Assistance Center/Training Site, Oak Ridge Institute for Science and Education, Oak Ridge Associated Universities, Oak Ridge, TN, USA.
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García Fernández F, Fabre E. The Dynamic Behavior of Chromatin in Response to DNA Double-Strand Breaks. Genes (Basel) 2022; 13:genes13020215. [PMID: 35205260 PMCID: PMC8872016 DOI: 10.3390/genes13020215] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
The primary functions of the eukaryotic nucleus as a site for the storage, retrieval, and replication of information require a highly dynamic chromatin organization, which can be affected by the presence of DNA damage. In response to double-strand breaks (DSBs), the mobility of chromatin at the break site is severely affected and, to a lesser extent, that of other chromosomes. The how and why of such movement has been widely studied over the last two decades, leading to different mechanistic models and proposed potential roles underlying both local and global mobility. Here, we review the state of the knowledge on current issues affecting chromatin mobility upon DSBs, and highlight its role as a crucial step in the DNA damage response (DDR).
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Affiliation(s)
- Fabiola García Fernández
- Institut Curie, CNRS UMR3664, Sorbonne Université, F-75005 Paris, France
- Correspondence: (F.G.F.); (E.F.)
| | - Emmanuelle Fabre
- Génomes Biologie Cellulaire et Thérapeutiques, CNRS UMR7212, INSERM U944, Université de Paris, F-75010 Paris, France
- Correspondence: (F.G.F.); (E.F.)
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Mackenroth B, Alani E. Collaborations between chromatin and nuclear architecture to optimize DNA repair fidelity. DNA Repair (Amst) 2021; 97:103018. [PMID: 33285474 PMCID: PMC8486310 DOI: 10.1016/j.dnarep.2020.103018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/18/2020] [Accepted: 11/05/2020] [Indexed: 01/22/2023]
Abstract
Homologous recombination (HR), considered the highest fidelity DNA double-strand break (DSB) repair pathway that a cell possesses, is capable of repairing multiple DSBs without altering genetic information. However, in "last resort" scenarios, HR can be directed to low fidelity subpathways which often use non-allelic donor templates. Such repair mechanisms are often highly mutagenic and can also yield chromosomal rearrangements and/or deletions. While the choice between HR and its less precise counterpart, non-homologous end joining (NHEJ), has received much attention, less is known about how cells manage and prioritize HR subpathways. In this review, we describe work focused on how chromatin and nuclear architecture orchestrate subpathway choice and repair template usage to maintain genome integrity without sacrificing cell survival. Understanding the relationships between nuclear architecture and recombination mechanics will be critical to understand these cellular repair decisions.
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Affiliation(s)
- Beata Mackenroth
- Department of Molecular Biology and Genetics, Cornell University, 459 Biotechnology Building, Ithaca, NY, 14853-2703, United States
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, 459 Biotechnology Building, Ithaca, NY, 14853-2703, United States.
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Abstract
A number of studies across different model systems revealed that chromatin undergoes significant changes in dynamics in response to DNA damage. These include local motion changes at damage sites, increased nuclear exploration of both damaged and undamaged loci, and directed motions to new nuclear locations associated with certain repair pathways. These studies also revealed the need for new analytical methods to identify directed motions in a context of mixed trajectories, and the importance of investigating nuclear dynamics over different time scales to identify diffusion regimes. Here we provide an overview of the current understanding of this field, including imaging and analytical methods developed to investigate nuclear dynamics in different contexts. These dynamics are essential for genome integrity. Identifying the molecular mechanisms responsible for these movements is key to understanding how their misregulation contributes to cancer and other genome instability disorders.
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Affiliation(s)
- Judith Miné-Hattab
- UMR 3664, CNRS, Institut Curie, PSL Research University, Paris, France
- UMR 3664, CNRS, Institut Curie, Sorbonne Université, Paris, France
| | - Irene Chiolo
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, United States
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Bártová E, Legartová S, Dundr M, Suchánková J. A role of the 53BP1 protein in genome protection: structural and functional characteristics of 53BP1-dependent DNA repair. Aging (Albany NY) 2019; 11:2488-511. [PMID: 30996128 DOI: 10.18632/aging.101917] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 04/10/2019] [Indexed: 12/13/2022]
Abstract
Nuclear architecture plays a significant role in DNA repair mechanisms. It is evident that proteins involved in DNA repair are compartmentalized in not only spontaneously occurring DNA lesions or ionizing radiation-induced foci (IRIF), but a specific clustering of these proteins can also be observed within the whole cell nucleus. For example, 53BP1-positive and BRCA1-positive DNA repair foci decorate chromocenters and can appear close to nuclear speckles. Both 53BP1 and BRCA1 are well-described factors that play an essential role in double-strand break (DSB) repair. These proteins are members of two protein complexes: 53BP1-RIF1-PTIP and BRCA1-CtIP, which make a “decision” determining whether canonical nonhomologous end joining (NHEJ) or homology-directed repair (HDR) is activated. It is generally accepted that 53BP1 mediates the NHEJ mechanism, while HDR is activated via a BRCA1-dependent signaling pathway. Interestingly, the 53BP1 protein appears relatively quickly at DSB sites, while BRCA1 is functional at later stages of DNA repair, as soon as the Mre11-Rad50-Nbs1 complex is recruited to the DNA lesions. A function of the 53BP1 protein is also linked to a specific histone signature, including phosphorylation of histone H2AX (γH2AX) or methylation of histone H4 at the lysine 20 position (H4K20me); therefore, we also discuss an epigenetic landscape of 53BP1-positive DNA lesions.
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Kesavan PS, Bohra D, Roy S, Mazumder A. Monitoring global changes in chromatin compaction states upon localized DNA damage with tools of fluorescence anisotropy. Mol Biol Cell 2020; 31:1403-1410. [PMID: 32320322 PMCID: PMC7353139 DOI: 10.1091/mbc.e19-08-0417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the eukaryotic nucleus, DNA, packaged in the form of chromatin, is subject to continuous damage. Chromatin has to be remodeled in order to repair such damage efficiently. But compact chromatin may also be more refractory to damage. Chromatin responses during DNA double-strand break (DSB) repair have been studied with biochemistry or as indirect readouts for the physical state of the chromatin at the site of damage. Direct measures of global chromatin compaction upon damage are lacking. We used fluorescence anisotropy imaging of histone H2B-EGFP to interrogate global chromatin compaction changes in response to localized DSBs directly. Anisotropy maps were preserved in fixation and reported on underlying chromatin compaction states. Laser-induced clustered DSBs led to global compaction of even the undamaged chromatin. Live-cell dynamics could be coupled with fixed-cell assays. Repair factors, PARP1 and PCNA, were immediately recruited to the site of damage, though the local enrichment of PCNA persisted longer than that of PARP1. Subsequently, nodes of PCNA that incorporated deoxynucleotide analogs were observed in regions of low-anisotropy open chromatin, even away from the site of damage. Such fluorescence anisotropy–based readout of chromatin compaction may be used in the investigation of different forms of DNA damage.
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Affiliation(s)
- P S Kesavan
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Hyderabad 500046, Telangana, India
| | - Darshika Bohra
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Hyderabad 500046, Telangana, India
| | - Sitara Roy
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Hyderabad 500046, Telangana, India
| | - Aprotim Mazumder
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Hyderabad 500046, Telangana, India
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Oshidari R, Mekhail K, Seeber A. Mobility and Repair of Damaged DNA: Random or Directed? Trends Cell Biol 2020; 30:144-156. [DOI: 10.1016/j.tcb.2019.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/24/2022]
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Zhu S, Paydar M, Wang F, Li Y, Wang L, Barrette B, Bessho T, Kwok BH, Peng A. Kinesin Kif2C in regulation of DNA double strand break dynamics and repair. eLife 2020; 9:53402. [PMID: 31951198 PMCID: PMC7012618 DOI: 10.7554/elife.53402] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/16/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double strand breaks (DSBs) have detrimental effects on cell survival and genomic stability, and are related to cancer and other human diseases. In this study, we identified microtubule-depolymerizing kinesin Kif2C as a protein associated with DSB-mimicking DNA templates and known DSB repair proteins in Xenopus egg extracts and mammalian cells. The recruitment of Kif2C to DNA damage sites was dependent on both PARP and ATM activities. Kif2C knockdown or knockout led to accumulation of endogenous DNA damage, DNA damage hypersensitivity, and reduced DSB repair via both NHEJ and HR. Interestingly, Kif2C depletion, or inhibition of its microtubule depolymerase activity, reduced the mobility of DSBs, impaired the formation of DNA damage foci, and decreased the occurrence of foci fusion and resolution. Taken together, our study established Kif2C as a new player of the DNA damage response, and presented a new mechanism that governs DSB dynamics and repair.
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Affiliation(s)
- Songli Zhu
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Mohammadjavad Paydar
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Feifei Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States.,Institute of Physical Science and Information Technology, Anhui University, Hefei, China
| | - Yanqiu Li
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Benoit Barrette
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Tadayoshi Bessho
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, United States
| | - Benjamin H Kwok
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
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Eaton JA, Zidovska A. Structural and Dynamical Signatures of Local DNA Damage in Live Cells. Biophys J 2020; 118:2168-80. [PMID: 31818467 DOI: 10.1016/j.bpj.2019.10.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/12/2019] [Accepted: 10/15/2019] [Indexed: 02/06/2023] Open
Abstract
The dynamic organization of chromatin inside the cell nucleus plays a key role in gene regulation and genome replication, as well as maintaining genome integrity. Although the static folded state of the genome has been extensively studied, dynamical signatures of processes such as transcription or DNA repair remain an open question. Here, we investigate the interphase chromatin dynamics in human cells in response to local DNA damage, specifically, DNA double-strand breaks (DSBs). Using simultaneous two-color spinning-disk confocal microscopy, we monitor the DSB dynamics and the compaction of the surrounding chromatin, visualized by fluorescently labeled 53BP1 and histone H2B, respectively. Our study reveals a surprising difference between the mobility of DSBs located in the nuclear interior versus periphery (less than 1 μm from the nuclear envelope), with the interior DSBs being almost twice as mobile as the periphery DSBs. Remarkably, we find that the DSB sites possess a robust structural signature in a form of a unique chromatin compaction profile. Moreover, our data show that the DSB motion is subdiffusive and ATP-dependent and exhibits unique dynamical signatures, different from those of undamaged chromatin. Our findings reveal that the DSB mobility follows a universal relationship defined solely by the physical parameters describing the DSBs and their local environment, such as the DSB focus size (represented by the local accumulation of 53BP1), DSB density, and the local chromatin compaction. This suggests that the DSB-related repair processes are robust and likely deterministic because the observed dynamical signatures (DSB mobility) can be explained solely by their structural features (DSB focus size, local chromatin compaction). Such knowledge might help in detecting local DNA damage in live cells, as well as in aiding our biophysical understanding of genome integrity in health and disease.
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Abstract
Genomic DNA is constantly exposed to damage. Among the lesion in DNA, double-strand breaks (DSB), because they disrupt the two strands of the DNA double helix, are the more dangerous. DSB are repaired through two evolutionary conserved mechanisms: Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR). Whereas NHEJ simply reseals the double helix with no or minimal processing, HR necessitates the formation of a 3'ssDNA through the processing of DSB ends by the resection machinery and relies on the recognition and pairing of this 3'ssDNA tails with an intact homologous sequence. Despite years of active research on HR, the manner by which the two homologous sequences find each other in the crowded nucleus, and how this modulates HR efficiency, only recently emerges. Here, we review recent advances in our understanding of the factors limiting the search of a homologous sequence during HR.
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Affiliation(s)
- Hélène Bordelet
- Laboratoire Instabilité et Organisation Nucléaire, iRCM, IBFJ, DRF, CEA. 2 INSERM, U967. 3 Université Paris Diderot et Paris Saclay, UMR967, Fontenay-aux-roses, 92265, France
| | - Karine Dubrana
- Laboratoire Instabilité et Organisation Nucléaire, iRCM, IBFJ, DRF, CEA. 2 INSERM, U967. 3 Université Paris Diderot et Paris Saclay, UMR967, Fontenay-aux-roses, 92265, France.
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14
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Whitefield DB, Spagnol ST, Armiger TJ, Lan L, Dahl KN. Quantifying site-specific chromatin mechanics and DNA damage response. Sci Rep 2018; 8:18084. [PMID: 30591710 DOI: 10.1038/s41598-018-36343-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 11/14/2018] [Indexed: 01/06/2023] Open
Abstract
DNA double-strand breaks pose a direct threat to genomic stability. Studies of DNA damage and chromatin dynamics have yielded opposing results that support either increased or decreased chromatin motion after damage. In this study, we independently measure the dynamics of transcriptionally active or repressed chromatin regions using particle tracking microrheology. We find that the baseline motion of transcriptionally repressed regions of chromatin are significantly less mobile than transcriptionally active chromatin, which is statistically similar to the bulk motion of chromatin within the nucleus. Site specific DNA damage using KillerRed tags induced in loci within repressed chromatin causes an increased motion, while loci within transcriptionally active regions remains unchanged at similar time scales. We also observe a time-dependent response associated with a further increase in chromatin decondensation. Global induction of damage with bleocin displays similar trends of chromatin decondensation and increased mobility only at 53BP1-labeled damage sites but not at non-damaged sites, indicating that chromatin dynamics are tightly regulated locally after damage. These results shed light on the evolution of the local and global DNA damage response associated with chromatin remodeling and dynamics, with direct implications for their role in repair.
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Abstract
Recent advances in both the technologies used to measure chromatin movement and the biophysical analysis used to model them have yielded a fuller understanding of chromatin dynamics and the polymer structure that underlies it. Changes in nucleosome packing, checkpoint kinase activation, the cell cycle, chromosomal tethers, and external forces acting on nuclei in response to external and internal stimuli can alter the basal mobility of DNA in interphase nuclei of yeast or mammalian cells. Although chromatin movement is assumed to be necessary for many DNA-based processes, including gene activation by distal enhancer–promoter interaction or sequence-based homology searches during double-strand break repair, experimental evidence supporting an essential role in these activities is sparse. Nonetheless, high-resolution tracking of chromatin dynamics has led to instructive models of the higher-order folding and flexibility of the chromatin polymer. Key regulators of chromatin motion in physiological conditions or after damage induction are reviewed here.
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Affiliation(s)
- Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
- Current affiliation: Harvard Center for Advanced Imaging, Cambridge, MA 02138, USA
| | - Michael H. Hauer
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
| | - Susan M. Gasser
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
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16
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McGinty RJ, Mirkin SM. Cis- and Trans-Modifiers of Repeat Expansions: Blending Model Systems with Human Genetics. Trends Genet 2018; 34:448-465. [PMID: 29567336 PMCID: PMC5959756 DOI: 10.1016/j.tig.2018.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/15/2018] [Accepted: 02/19/2018] [Indexed: 12/30/2022]
Abstract
Over 30 hereditary diseases are caused by the expansion of microsatellite repeats. The length of the expandable repeat is the main hereditary determinant of these disorders. They are also affected by numerous genomic variants that are either nearby (cis) or physically separated from (trans) the repetitive locus, which we review here. These genetic variants have largely been elucidated in model systems using gene knockouts, while a few have been directly observed as single-nucleotide polymorphisms (SNPs) in patients. There is a notable disconnect between these two bodies of knowledge: knockouts poorly approximate the SNP-level variation in human populations that gives rise to medically relevant cis- and trans-modifiers, while the rarity of these diseases limits the statistical power of SNP-based analysis in humans. We propose that high-throughput SNP-based screening in model systems could become a useful approach to quickly identify and characterize modifiers of clinical relevance for patients.
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Affiliation(s)
- Ryan J McGinty
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA.
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17
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Caridi PC, Delabaere L, Zapotoczny G, Chiolo I. And yet, it moves: nuclear and chromatin dynamics of a heterochromatic double-strand break. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0291. [PMID: 28847828 PMCID: PMC5577469 DOI: 10.1098/rstb.2016.0291] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2017] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is mostly composed of repeated DNA sequences prone to aberrant recombination. How cells maintain the stability of these sequences during double-strand break (DSB) repair has been a long-standing mystery. Studies in Drosophila cells revealed that faithful homologous recombination repair of heterochromatic DSBs relies on the striking relocalization of repair sites to the nuclear periphery before Rad51 recruitment and repair progression. Here, we summarize our current understanding of this response, including the molecular mechanisms involved, and conserved pathways in mammalian cells. We will highlight important similarities with pathways identified in budding yeast for repair of other types of repeated sequences, including rDNA and short telomeres. We will also discuss the emerging role of chromatin composition and regulation in heterochromatin repair progression. Together, these discoveries challenged previous assumptions that repair sites are substantially static in multicellular eukaryotes, that heterochromatin is largely inert in the presence of DSBs, and that silencing and compaction in this domain are obstacles to repair. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.
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Affiliation(s)
- P Christopher Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
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18
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Sollazzo A, Brzozowska B, Cheng L, Lundholm L, Scherthan H, Wojcik A. Live Dynamics of 53BP1 Foci Following Simultaneous Induction of Clustered and Dispersed DNA Damage in U2OS Cells. Int J Mol Sci 2018; 19:E519. [PMID: 29419809 DOI: 10.3390/ijms19020519] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/18/2018] [Accepted: 01/30/2018] [Indexed: 12/19/2022] Open
Abstract
Cells react differently to clustered and dispersed DNA double strand breaks (DSB). Little is known about the initial reaction to simultaneous induction of DSBs with different complexities. Here, we used live cell microscopy to analyse the behaviour of 53BP1-GFP (green fluorescence protein) foci formation at DSBs induced in U2OS cells by alpha particles, X-rays or mixed beams over a 75 min period post irradiation. X-ray-induced foci rapidly increased and declined over the observation interval. After an initial increase, mixed beam-induced foci remained at a constant level over the observation interval, similarly as alpha-induced foci. The average areas of radiation-induced foci were similar for mixed beams and X-rays, being significantly smaller than those induced by alpha particles. Pixel intensities were highest for mixed beam-induced foci and showed the lowest level of variability over time as compared to foci induced by alphas and X-rays alone. Finally, mixed beam-exposed foci showed the lowest level of mobility as compared to alpha and X-ray exposure. The results suggest paralysation of chromatin around foci containing clustered DNA damage.
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19
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Nair N, Shoaib M, Sørensen CS. Chromatin Dynamics in Genome Stability: Roles in Suppressing Endogenous DNA Damage and Facilitating DNA Repair. Int J Mol Sci 2017; 18:E1486. [PMID: 28698521 DOI: 10.3390/ijms18071486] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/01/2017] [Accepted: 07/04/2017] [Indexed: 02/06/2023] Open
Abstract
Genomic DNA is compacted into chromatin through packaging with histone and non-histone proteins. Importantly, DNA accessibility is dynamically regulated to ensure genome stability. This is exemplified in the response to DNA damage where chromatin relaxation near genomic lesions serves to promote access of relevant enzymes to specific DNA regions for signaling and repair. Furthermore, recent data highlight genome maintenance roles of chromatin through the regulation of endogenous DNA-templated processes including transcription and replication. Here, we review research that shows the importance of chromatin structure regulation in maintaining genome integrity by multiple mechanisms including facilitating DNA repair and directly suppressing endogenous DNA damage.
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20
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Aymard F, Aguirrebengoa M, Guillou E, Javierre BM, Bugler B, Arnould C, Rocher V, Iacovoni JS, Biernacka A, Skrzypczak M, Ginalski K, Rowicka M, Fraser P, Legube G. Genome-wide mapping of long-range contacts unveils clustering of DNA double-strand breaks at damaged active genes. Nat Struct Mol Biol 2017; 24:353-61. [PMID: 28263325 DOI: 10.1038/nsmb.3387] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 02/07/2017] [Indexed: 12/29/2022]
Abstract
The ability of DNA Double Strand Breaks (DSBs) to cluster in mammalian cells has been subjected to intense debate over the past few years. Here we used a high throughput chromosome conformation capture assay (Capture Hi-C) to investigate clustering of DSBs induced at defined loci in the human genome. We unambiguously found that DSBs do cluster but only when induced in transcriptionally active genes. Clustering of damaged genes mainly occurs during the G1 cell cycle phase and coincides with delayed repair. Moreover DSB clustering depends on the MRN complex, as well as the Formin 2 (FMN2) nuclear actin organizer and the LINC (LInker of Nuclear and Cytoplasmic skeleton) complex, suggesting that active mechanisms promote DSB clustering. This work reveals that when damaged, active genes exhibit a very peculiar behavior compared to the rest of the genome, being mostly left unrepaired and clustered in G1 while being repaired by homologous recombination in post-replicative cells.
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21
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Yamauchi M, Shibata A, Suzuki K, Suzuki M, Niimi A, Kondo H, Miura M, Hirakawa M, Tsujita K, Yamashita S, Matsuda N. Regulation of pairing between broken DNA-containing chromatin regions by Ku80, DNA-PKcs, ATM, and 53BP1. Sci Rep 2017; 7:41812. [PMID: 28155885 PMCID: PMC5290537 DOI: 10.1038/srep41812] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/28/2016] [Indexed: 12/12/2022] Open
Abstract
Chromosome rearrangement is clinically and physiologically important because it can produce oncogenic fusion genes. Chromosome rearrangement requires DNA double-strand breaks (DSBs) at two genomic locations and misrejoining between the DSBs. Before DSB misrejoining, two DSB-containing chromatin regions move and pair with each other; however, the molecular mechanism underlying this process is largely unknown. We performed a spatiotemporal analysis of ionizing radiation-induced foci of p53-binding protein 1 (53BP1), a marker for DSB-containing chromatin. We found that some 53BP1 foci were paired, indicating that the two damaged chromatin regions neighboured one another. We searched for factors regulating the foci pairing and found that the number of paired foci increased when Ku80, DNA-PKcs, or ATM was absent. In contrast, 53BP1 depletion reduced the number of paired foci and dicentric chromosomes—an interchromosomal rearrangement. Foci were paired more
frequently in heterochromatin than in euchromatin in control cells. Additionally, the reduced foci pairing in 53BP1-depleted cells was rescued by concomitant depletion of a heterochromatin building factor such as Krüppel-associated box-associated protein 1 or chromodomain helicase DNA-binding protein 3. These findings indicate that pairing between DSB-containing chromatin regions was suppressed by Ku80, DNA-PKcs, and ATM, and this pairing was promoted by 53BP1 through chromatin relaxation.
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Affiliation(s)
- Motohiro Yamauchi
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Atsushi Shibata
- Advanced Scientific Research Leaders Development Unit, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Keiji Suzuki
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Masatoshi Suzuki
- Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku Sendai, Miyagi, 980-8575, Japan
| | - Atsuko Niimi
- Research Program for Heavy Ion Therapy, Division of Integrated Oncology Research, Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Hisayoshi Kondo
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Miwa Miura
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Miyako Hirakawa
- Radioisotope Research Center, Life Science Support Center, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Keiko Tsujita
- School of Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Shunichi Yamashita
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Naoki Matsuda
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
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22
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Marnef A, Legube G. Organizing DNA repair in the nucleus: DSBs hit the road. Curr Opin Cell Biol 2017; 46:1-8. [PMID: 28068556 DOI: 10.1016/j.ceb.2016.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 11/30/2016] [Accepted: 12/12/2016] [Indexed: 10/20/2022]
Abstract
In the past decade, large-scale movements of DNA double strand breaks (DSBs) have repeatedly been identified following DNA damage. These mobility events include clustering, anchoring or peripheral movement at subnuclear structures. Recent work suggests roles for motion in homology search and in break sequestration to preclude deleterious outcomes. Yet, the precise functions of these movements still remain relatively obscure, and the same holds true for the determinants. Here we review recent advances in this exciting area of research, and highlight that a recurrent characteristic of mobile DSBs may lie in their inability to undergo rapid repair. A major future challenge remains to understand how DSB mobility impacts on genome integrity.
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Affiliation(s)
- Aline Marnef
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, France
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, France.
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23
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Harding SM, Greenberg RA. Choreographing the Double Strand Break Response: Ubiquitin and SUMO Control of Nuclear Architecture. Front Genet 2016; 7:103. [PMID: 27375678 PMCID: PMC4894868 DOI: 10.3389/fgene.2016.00103] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/24/2016] [Indexed: 12/16/2022] Open
Abstract
The cellular response to DNA double strand breaks (DSBs) is a multifaceted signaling program that centers on post-translational modifications including phosphorylation, ubiquitylation and SUMOylation. In this review we discuss how ubiquitin and SUMO orchestrate the recognition of DSBs and explore how this influences chromatin organization. We discuss functional outcomes of this response including transcriptional silencing and how pre-existing chromatin states may control the DSB response and the maintenance of genomic stability.
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Affiliation(s)
- Shane M Harding
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
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24
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Lorat Y, Schanz S, Rübe CE. Ultrastructural Insights into the Biological Significance of Persisting DNA Damage Foci after Low Doses of Ionizing Radiation. Clin Cancer Res 2016; 22:5300-5311. [PMID: 27199493 DOI: 10.1158/1078-0432.ccr-15-3081] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/07/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Intensity-modulated radiotherapy (IMRT) enables the delivery of high doses to target volume while sparing surrounding nontargeted tissues. IMRT treatment, however, substantially increases the normal tissue volume receiving low-dose irradiation, but the biologic consequences are unclear. EXPERIMENTAL DESIGN Using mouse strains that varied in genetic DNA repair capacity, we investigated the DNA damage response of cortical neurons during daily low-dose irradiation (0.1 Gy). Using light and electron microscopic approaches, we enumerated and characterized DNA damage foci as marker for double-strand breaks (DSBs). RESULTS During repeated low-dose irradiation, cortical neurons in brain tissues of all mouse strains had a significant increase of persisting foci with cumulative doses, with the most pronounced accumulation of large-sized foci in repair-deficient mice. Electron microscopic analysis revealed that persisting foci in repair-proficient neurons reflect chromatin alterations in heterochromatin, but not persistently unrepaired DSBs. Repair-deficient SCID neurons, by contrast, showed high numbers of unrepaired DSBs in eu- and heterochromatin, emphasizing the fundamental role of DNA-PKcs in DSB rejoining, independent of chromatin status. In repair-deficient ATM-/- neurons, large persisting damage foci reflect multiple unrepaired DSBs concentrated at the boundary of heterochromatin due to disturbed KAP1 phosphorylation. CONCLUSION Repeated low-dose irradiation leads to the accumulation of persisting DNA damage foci in cortical neurons and thus may adversely affect brain tissue and increase the risk of carcinogenesis. Multiple unrepaired DSBs account for large-sized foci in repair-deficient neurons, thus quantifying foci alone may underestimate extent and complexity of persistent DNA damage. Clin Cancer Res; 22(21); 5300-11. ©2016 AACR.
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Affiliation(s)
- Yvonne Lorat
- Department of Radiation Oncology, Saarland University, Homburg, Saarland, Germany
| | - Stefanie Schanz
- Department of Radiation Oncology, Saarland University, Homburg, Saarland, Germany
| | - Claudia E Rübe
- Department of Radiation Oncology, Saarland University, Homburg, Saarland, Germany.
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25
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Abstract
Ataxia telangiectasia mutated (ATM) has been known for decades as the main kinase mediating the DNA double-strand break response. Our recent findings suggest that its major role at the sites of breaks likely resides in its ability to modify both the local chromatin landscape and the global chromosome organization in order to promote repair accuracy.
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Affiliation(s)
- Francois Aymard
- LBCMCP, Center for Integrative Biology (CBI), Université de Toulouse, UT3, Toulouse, France; LBCMCP, Center for Integrative Biology (CBI), CNRS, Toulouse, France
| | - Gaëlle Legube
- LBCMCP, Center for Integrative Biology (CBI), Université de Toulouse, UT3, Toulouse, France; LBCMCP, Center for Integrative Biology (CBI), CNRS, Toulouse, France
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26
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Lottersberger F, Karssemeijer RA, Dimitrova N, de Lange T. 53BP1 and the LINC Complex Promote Microtubule-Dependent DSB Mobility and DNA Repair. Cell 2016; 163:880-93. [PMID: 26544937 DOI: 10.1016/j.cell.2015.09.057] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 01/13/2023]
Abstract
Increased mobility of chromatin surrounding double-strand breaks (DSBs) has been noted in yeast and mammalian cells but the underlying mechanism and its contribution to DSB repair remain unclear. Here, we use a telomere-based system to track DNA damage foci with high resolution in living cells. We find that the greater mobility of damaged chromatin requires 53BP1, SUN1/2 in the linker of the nucleoskeleton, and cytoskeleton (LINC) complex and dynamic microtubules. The data further demonstrate that the excursions promote non-homologous end joining of dysfunctional telomeres and implicated Nesprin-4 and kinesins in telomere fusion. 53BP1/LINC/microtubule-dependent mobility is also evident at irradiation-induced DSBs and contributes to the mis-rejoining of drug-induced DSBs in BRCA1-deficient cells showing that DSB mobility can be detrimental in cells with numerous DSBs. In contrast, under physiological conditions where cells have only one or a few lesions, DSB mobility is proposed to prevent errors in DNA repair.
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Affiliation(s)
- Francisca Lottersberger
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Roos Anna Karssemeijer
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Nadya Dimitrova
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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27
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Caron P, Choudjaye J, Clouaire T, Bugler B, Daburon V, Aguirrebengoa M, Mangeat T, Iacovoni JS, Álvarez-Quilón A, Cortés-Ledesma F, Legube G. Non-redundant Functions of ATM and DNA-PKcs in Response to DNA Double-Strand Breaks. Cell Rep 2015; 13:1598-609. [PMID: 26586426 PMCID: PMC4670905 DOI: 10.1016/j.celrep.2015.10.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 09/04/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022] Open
Abstract
DNA double-strand breaks (DSBs) elicit the so-called DNA damage response (DDR), largely relying on ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PKcs), two members of the PI3K-like kinase family, whose respective functions during the sequential steps of the DDR remains controversial. Using the DIvA system (DSB inducible via AsiSI) combined with high-resolution mapping and advanced microscopy, we uncovered that both ATM and DNA-PKcs spread in cis on a confined region surrounding DSBs, independently of the pathway used for repair. However, once recruited, these kinases exhibit non-overlapping functions on end joining and γH2AX domain establishment. More specifically, we found that ATM is required to ensure the association of multiple DSBs within "repair foci." Our results suggest that ATM acts not only on chromatin marks but also on higher-order chromatin organization to ensure repair accuracy and survival.
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Affiliation(s)
- Pierre Caron
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jonathan Choudjaye
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Clouaire
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Béatrix Bugler
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Virginie Daburon
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Marion Aguirrebengoa
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Thomas Mangeat
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France
| | - Jason S Iacovoni
- Bioinformatic Plateau I2MC, INSERM and University of Toulouse, 1 Avenue Jean Poulhes, BP 84225, 31432 Toulouse Cedex 4, France
| | - Alejandro Álvarez-Quilón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Felipe Cortés-Ledesma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla, Sevilla 41092, Spain
| | - Gaëlle Legube
- Université de Toulouse, UPS, LBCMCP, 118 route de Narbonne, 31062 Toulouse, France; CNRS, LBCMCP, 31062 Toulouse, France.
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28
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Abstract
The past 20 years have seen dramatic changes in the delivery of radiation therapy, but the impact of radiobiology on the clinic has been far less substantial. A major consideration in the use of radiotherapy has been on how best to exploit differences between the tumour and host tissue characteristics, which in the past has been achieved empirically by radiation-dose fractionation. New advances are uncovering some of the mechanistic processes that underlie this success story. In this Review, we focus on how these processes might be targeted to improve the outcome of radiotherapy at the individual patient level. This approach would seem a more productive avenue of treatment than simply trying to increase the radiation dose delivered to the tumour.
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Affiliation(s)
- Dörthe Schaue
- Department of Radiation Oncology, Room B3-109, Center for Health Sciences, Westwood, University of California, Los Angeles (UCLA), Los Angeles, CA 90095-1714, USA
| | - William H McBride
- Department of Radiation Oncology, Room B3-109, Center for Health Sciences, Westwood, University of California, Los Angeles (UCLA), Los Angeles, CA 90095-1714, USA
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29
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Gelot C, Magdalou I, Lopez BS. Replication stress in Mammalian cells and its consequences for mitosis. Genes (Basel) 2015; 6:267-98. [PMID: 26010955 DOI: 10.3390/genes6020267] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/15/2015] [Accepted: 05/18/2015] [Indexed: 12/23/2022] Open
Abstract
The faithful transmission of genetic information to daughter cells is central to maintaining genomic stability and relies on the accurate and complete duplication of genetic material during each cell cycle. However, the genome is routinely exposed to endogenous and exogenous stresses that can impede the progression of replication. Such replication stress can be an early cause of cancer or initiate senescence. Replication stress, which primarily occurs during S phase, results in consequences during mitosis, jeopardizing chromosome segregation and, in turn, genomic stability. The traces of replication stress can be detected in the daughter cells during G1 phase. Alterations in mitosis occur in two types: 1) local alterations that correspond to breaks, rearrangements, intertwined DNA molecules or non-separated sister chromatids that are confined to the region of the replication dysfunction; 2) genome-wide chromosome segregation resulting from centrosome amplification (although centrosomes do not contain DNA), which amplifies the local replication stress to the entire genome. Here, we discuss the endogenous causes of replication perturbations, the mechanisms of replication fork restart and the consequences for mitosis, chromosome segregation and genomic stability.
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