1
|
Tang Z, Liang Z, Zhang B, Xu X, Li P, Li L, Lu LY, Liu Y. MRE11 is essential for the long-term viability of undifferentiated spermatogonia. Cell Prolif 2024:e13685. [PMID: 38894566 DOI: 10.1111/cpr.13685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
In the meiotic prophase, programmed SPO11-linked DNA double-strand breaks (DSBs) are repaired by homologous recombination (HR). The MRE11-RAD50-NBS1 (MRN) complex is essential for initiating DNA end resection, the first step of HR. However, residual DNA end resection still occurs in Nbs1 knockout (KO) spermatocytes for unknown reasons. Here, we show that DNA end resection is completely abolished in Mre11 KO spermatocytes. In addition, Mre11 KO, but not Nbs1 KO, undifferentiated spermatogonia are rapidly exhausted due to DSB accumulation, proliferation defects, and elevated apoptosis. Cellular studies reveal that a small amount of MRE11 retained in the nucleus of Nbs1 KO cells likely underlies the differences between Mre11 and Nbs1 KO cells. Taken together, our study not only demonstrates an irreplaceable role of the MRE11 in DNA end resection at SPO11-linked DSBs but also unveils a unique function of MRE11 in maintaining the long-term viability of undifferentiated spermatogonia.
Collapse
Affiliation(s)
- Zhenghui Tang
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhongyang Liang
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Bin Zhang
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaohui Xu
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Peng Li
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Key Laboratory of Maternal and Infant Health, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lejun Li
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Key Laboratory of Maternal and Infant Health, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lin-Yu Lu
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang University Cancer Center, Hangzhou, China
| | - Yidan Liu
- Key Laboratory of Reproductive Genetics (Ministry of Education), Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
2
|
Petroni M, La Monica V, Fabretti F, Augusto M, Battaglini D, Polonara F, Di Giulio S, Giannini G. The Multiple Faces of the MRN Complex: Roles in Medulloblastoma and Beyond. Cancers (Basel) 2023; 15:3599. [PMID: 37509263 PMCID: PMC10377613 DOI: 10.3390/cancers15143599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/09/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Hypomorphic mutations in MRN complex genes are frequently found in cancer, supporting their role as oncosuppressors. However, unlike canonical oncosuppressors, MRN proteins are often overexpressed in tumor tissues, where they actively work to counteract DSBs induced by both oncogene-dependent RS and radio-chemotherapy. Moreover, at the same time, MRN genes are also essential genes, since the constitutive KO of each component leads to embryonic lethality. Therefore, even though it is paradoxical, MRN genes may work as oncosuppressive, oncopromoting, and essential genes. In this review, we discussed how alterations in the MRN complex impact the physiopathology of cancer, in light of our recent discoveries on the gene-dosage-dependent effect of NBS1 in Medulloblastoma. These updates aim to understand whether MRN complex can be realistically used as a prognostic/predictive marker and/or as a therapeutic target for the treatment of cancer patients in the future.
Collapse
Affiliation(s)
- Marialaura Petroni
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Veronica La Monica
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Fabretti
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Mariaconcetta Augusto
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Damiana Battaglini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Francesca Polonara
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Stefano Di Giulio
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - Giuseppe Giannini
- Department of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, 00161 Rome, Italy
| |
Collapse
|
3
|
Hamilton NA, Jehru AE, Samples WN, Wendel BM, Mokhtari PD, Courcelle CT, Courcelle J. chi sequences switch the RecBCD helicase-nuclease complex from degradative to replicative modes during the completion of DNA replication. J Biol Chem 2023; 299:103013. [PMID: 36781123 PMCID: PMC10025158 DOI: 10.1016/j.jbc.2023.103013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023] Open
Abstract
Accurately completing DNA replication when two forks converge is essential to genomic stability. The RecBCD helicase-nuclease complex plays a central role in completion by promoting resection and joining of the excess DNA created when replisomes converge. chi sequences alter RecBCD activity and localize with cross-over hotspots during sexual events in bacteria, yet their functional role during chromosome replication remains unknown. Here, we use two-dimensional agarose gel analysis to show that chi induces replication on substrates containing convergent forks. The induced-replication is processive, but uncoupled with respect to leading and lagging strand synthesis, and can be suppressed by ter sites which limit replisome progression. Our observations demonstrate that convergent replisomes create a substrate that is processed by RecBCD, and that chi, when encountered, switches RecBCD from a degradative to replicative function. We propose that chi serves to functionally differentiate DNA ends created during completion, which require degradation, from those created by chromosomal double-strand breaks, which require resynthesis.
Collapse
Affiliation(s)
| | - Avery E. Jehru
- Department of Biology, Portland State University, Portland, Oregon, USA
| | | | - Brian M. Wendel
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | | | | | - Justin Courcelle
- Department of Biology, Portland State University, Portland, Oregon, USA
- For correspondence: Justin Courcelle
| |
Collapse
|
4
|
Schuhwerk H, Kleemann J, Gupta P, van Roey R, Armstark I, Kreileder M, Feldker N, Ramesh V, Hajjaj Y, Fuchs K, Mahapatro M, Hribersek M, Volante M, Groenewoud A, Engel FB, Ceppi P, Eckstein M, Hartmann A, Müller F, Kroll T, Stemmler MP, Brabletz S, Brabletz T. The EMT transcription factor ZEB1 governs a fitness-promoting but vulnerable DNA replication stress response. Cell Rep 2022; 41:111819. [PMID: 36516781 DOI: 10.1016/j.celrep.2022.111819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/14/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
The DNA damage response (DDR) and epithelial-to-mesenchymal transition (EMT) are two crucial cellular programs in cancer biology. While the DDR orchestrates cell-cycle progression, DNA repair, and cell death, EMT promotes invasiveness, cellular plasticity, and intratumor heterogeneity. Therapeutic targeting of EMT transcription factors, such as ZEB1, remains challenging, but tumor-promoting DDR alterations elicit specific vulnerabilities. Using multi-omics, inhibitors, and high-content microscopy, we discover a chemoresistant ZEB1-high-expressing sub-population (ZEB1hi) with co-rewired cell-cycle progression and proficient DDR across tumor entities. ZEB1 stimulates accelerated S-phase entry via CDK6, inflicting endogenous DNA replication stress. However, DDR buildups involving constitutive MRE11-dependent fork resection allow homeostatic cycling and enrichment of ZEB1hi cells during transforming growth factor β (TGF-β)-induced EMT and chemotherapy. Thus, ZEB1 promotes G1/S transition to launch a progressive DDR benefitting stress tolerance, which concurrently manifests a targetable vulnerability in chemoresistant ZEB1hi cells. Our study thus highlights the translationally relevant intercept of the DDR and EMT.
Collapse
Affiliation(s)
- Harald Schuhwerk
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany.
| | - Julia Kleemann
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Pooja Gupta
- Core Unit for Bioinformatics, Data Integration and Analysis, Center for Medical Information and Communication Technology, University Hospital Erlangen, Erlangen Germany
| | - Ruthger van Roey
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Isabell Armstark
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Martina Kreileder
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Nora Feldker
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Vignesh Ramesh
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Yussuf Hajjaj
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Kathrin Fuchs
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Mousumi Mahapatro
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Mojca Hribersek
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Marco Volante
- Department of Oncology, University of Turin, Orbassano, Turin, Italy
| | - Arwin Groenewoud
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Felix B Engel
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Paolo Ceppi
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Markus Eckstein
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen- Nürnberg, Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Arndt Hartmann
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen- Nürnberg, Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Fabian Müller
- Department of Internal Medicine 5, Haematology and Oncology, University Hospital Erlangen, Erlangen Germany
| | - Torsten Kroll
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Jena, Germany
| | - Marc P Stemmler
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Simone Brabletz
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Brabletz
- Department of Experimental Medicine 1, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
| |
Collapse
|
5
|
Petroni M, Fabretti F, Giulio SD, Robilant VND, Monica VL, Moretti M, Belardinilli F, Bufalieri F, Anna C, Paci P, Corsi A, Smaele ED, Coni S, Canettieri G, Marcotullio LD, Wang ZQ, Giannini G. A gene dosage-dependent effect unveils NBS1 as both a haploinsufficient tumour suppressor and an essential gene for SHH-medulloblastoma. Neuropathol Appl Neurobiol 2022; 48:e12837. [PMID: 35839783 PMCID: PMC9542137 DOI: 10.1111/nan.12837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/10/2022] [Accepted: 07/05/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Inherited or somatic mutations in the MRE11, RAD50 and NBN genes increase the incidence of tumours, including medulloblastoma (MB). On the other hand, MRE11, RAD50 and NBS1 protein components of the MRN complex are often overexpressed and sometimes essential in cancer. In order to solve the apparent conundrum about the oncosuppressive or oncopromoting role of the MRN complex, we explored the functions of NBS1 in a MB prone animal model. MATERIALS AND METHODS We generated and analysed mono- or biallelic deletion of the Nbn gene in the context of the SmoA1 transgenic mouse, a SHH-dependent MB prone animal model. We used normal and tumour tissue from these animal models, primary granule cell progenitors (GCPs) from genetically modified animals, and NBS1-depleted primary MB cells, to uncover the effects of NBS1-depletion by RNA-Seq, by biochemical characterization of the SHH-pathway and the DNA damage response (DDR) as well as on the growth and clonogenic properties of GCPs. RESULTS We found that monoallelic Nbn deletion increases SmoA1-dependent MB incidence. In addition to a defective DDR, Nbn+/- GCPs show increased clonogenicity compared to Nbn+/+ GCPs, dependent on an enhanced Notch signalling. In contrast, full NbnKO impairs MB development both in SmoA1 mice and in a SHH-driven tumour allograft. CONCLUSIONS Our study indicates that Nbn is haploinsufficient for SHH-MB development while full NbnKO is epistatic on SHH-driven MB development, thus revealing a gene dosage-dependent effect of Nbn inactivation on SHH-MB development.
Collapse
Affiliation(s)
- Marialaura Petroni
- Dept. of Molecular Medicine, University La Sapienza, Rome, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Rome, Italy
| | | | | | | | | | - Marta Moretti
- Dept. of Experimental Medicine, University La Sapienza, Rome, Italy
| | | | | | - Coppa Anna
- Dept. of Experimental Medicine, University La Sapienza, Rome, Italy
| | - Paola Paci
- Dep. of Computer Engineering, Automation and Management, University La Sapienza, Rome, Italy.,Institute for Systems Analysis and Computer Science Antonio Ruberti, National Research Council, Rome, Italy
| | - Alessandro Corsi
- Dept. of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Enrico De Smaele
- Dept. of Experimental Medicine, University La Sapienza, Rome, Italy
| | - Sonia Coni
- Dept. of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Gianluca Canettieri
- Dept. of Molecular Medicine, University La Sapienza, Rome, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Rome, Italy
| | | | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI) Beutenbergstrasse 11, Jena, Germany
| | - Giuseppe Giannini
- Dept. of Molecular Medicine, University La Sapienza, Rome, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Rome, Italy
| |
Collapse
|
6
|
Martins S, Erichsen L, Datsi A, Wruck W, Goering W, Chatzantonaki E, de Amorim VCM, Rossi A, Chrzanowska KH, Adjaye J. Impaired p53-Mediated DNA Damage Response Contributes to Microcephaly in Nijmegen Breakage Syndrome Patient-Derived Cerebral Organoids. Cells 2022; 11:cells11050802. [PMID: 35269426 PMCID: PMC8909307 DOI: 10.3390/cells11050802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/18/2022] [Indexed: 12/11/2022] Open
Abstract
Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder caused by mutations within nibrin (NBN), a DNA damage repair protein. Hallmarks of NBS include chromosomal instability and clinical manifestations such as growth retardation, immunodeficiency, and progressive microcephaly. We employed induced pluripotent stem cell-derived cerebral organoids from two NBS patients to study the etiology of microcephaly. We show that NBS organoids carrying the homozygous 657del5 NBN mutation are significantly smaller with disrupted cyto-architecture. The organoids exhibit premature differentiation, and Neuronatin (NNAT) over-expression. Furthermore, pathways related to DNA damage response and cell cycle are differentially regulated compared to controls. After exposure to bleomycin, NBS organoids undergo delayed p53-mediated DNA damage response and aberrant trans-synaptic signaling, which ultimately leads to neuronal apoptosis. Our data provide insights into how mutations within NBN alters neurogenesis in NBS patients, thus providing a proof of concept that cerebral organoids are a valuable tool for studying DNA damage-related disorders.
Collapse
Affiliation(s)
- Soraia Martins
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
| | - Lars Erichsen
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
| | - Angeliki Datsi
- Institute for Transplantation Diagnostics and Cell Therapeutics, Heinrich-Heine University, 40225 Düsseldorf, Germany;
| | - Wasco Wruck
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
| | - Wolfgang Goering
- Institute for Pathology, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany;
| | - Eleftheria Chatzantonaki
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
| | - Vanessa Cristina Meira de Amorim
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
| | - Andrea Rossi
- IUF-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany;
| | - Krystyna H. Chrzanowska
- Department of Medical Genetics, Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - James Adjaye
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany; (S.M.); (L.E.); (W.W.); (E.C.); (V.C.M.d.A.)
- Correspondence:
| |
Collapse
|
7
|
Ding M, Qing X, Zhang G, Baade-Büttner C, Gruber R, Lu H, Ferguson DO, Geis C, Wang ZQ, Zhou ZW. The Essential DNA Damage Response Complex MRN Is Dispensable for the Survival and Function of Purkinje Neurons. Front Aging Neurosci 2022; 13:786199. [PMID: 35153719 PMCID: PMC8831373 DOI: 10.3389/fnagi.2021.786199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/29/2021] [Indexed: 11/30/2022] Open
Abstract
MRE11, RAD50, and NBS1 form the MRN complex in response to DNA damage to activate ATM, a gene responsible for Ataxia-Telangiectasia (A-T). Loss of any components of the MRN complex compromises cell life. Mutations in MRE11, RAD50, and NBS1 cause human genomic instability syndromes Ataxia-Telangiectasia-like disorder (A-TLD), NBS-like disorder (NBSLD), and Nijmegen Breakage Syndrome (NBS), respectively. Among other pathologies, neuronal deficits, including microcephaly, intellectual disabilities, and progressive cerebellar degeneration, are common in these disorders. Nbs1 deletion in neural stem cells of mouse models resulted in cerebellar atrophy and ataxia, mimicking the A-T syndrome suggesting an etiological function of MRN-mediated DDR in neuronal homeostasis and neuropathology. Here we show that deletion of Nbs1 or Mre11 specifically in Purkinje neurons of mouse models (Nbs1-PCΔ and Mre11-PCΔ, respectively) is compatible with cerebellar development. Deleting Nbs1 in Purkinje cells disrupts the cellular localization pattern of MRE11 or RAD50 without inducing apparent DNA damage, albeit impaired DNA damage response (judged by 53BP1 focus formation) to ionizing radiation (IR). However, neither survival nor morphology of Purkinje cells and thus locomotor capabilities is affected by Nbs1 deletion under physiological conditions. Similarly, deletion of Mre11 in Purkinje cells does not affect the numbers or morphology of Purkinje cells and causes no accumulation of DNA damage. Mre11-deleted Purkinje cells have regular intrinsic neuronal activity. Taken together, these data indicate that the MRN complex is not essential for the survival and functionality of postmitotic neurons such as Purkinje cells. Thus, cerebellar deficits in MRN defect-related disorders and mouse models are unlikely to be a direct consequence of loss of these factors compromising DDR in postmitotic neurons such as Purkinje cells.
Collapse
Affiliation(s)
- Mingmei Ding
- School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Xiaobing Qing
- Leibniz Institute on Aging – Fritz Lipmann Institute (FLI), Jena, Germany
| | - Guangyu Zhang
- Leibniz Institute on Aging – Fritz Lipmann Institute (FLI), Jena, Germany
| | - Carolin Baade-Büttner
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Jena, Germany
| | - Ralph Gruber
- Leibniz Institute on Aging – Fritz Lipmann Institute (FLI), Jena, Germany
| | - Haizhen Lu
- Department of Pathology and Resident Training Base, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - David O. Ferguson
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Christian Geis
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Jena, Germany
| | - Zhao-Qi Wang
- Leibniz Institute on Aging – Fritz Lipmann Institute (FLI), Jena, Germany
- Faculty of Biological Sciences, Friedrich-Schiller-University of Jena, Jena, Germany
- *Correspondence: Zhao-Qi Wang,
| | - Zhong-Wei Zhou
- School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- Leibniz Institute on Aging – Fritz Lipmann Institute (FLI), Jena, Germany
- Zhong-Wei Zhou,
| |
Collapse
|
8
|
Lu R, Zhang H, Jiang YN, Wang ZQ, Sun L, Zhou ZW. Post-Translational Modification of MRE11: Its Implication in DDR and Diseases. Genes (Basel) 2021; 12:1158. [PMID: 34440334 PMCID: PMC8392716 DOI: 10.3390/genes12081158] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 12/15/2022] Open
Abstract
Maintaining genomic stability is vital for cells as well as individual organisms. The meiotic recombination-related gene MRE11 (meiotic recombination 11) is essential for preserving genomic stability through its important roles in the resection of broken DNA ends, DNA damage response (DDR), DNA double-strand breaks (DSBs) repair, and telomere maintenance. The post-translational modifications (PTMs), such as phosphorylation, ubiquitination, and methylation, regulate directly the function of MRE11 and endow MRE11 with capabilities to respond to cellular processes in promptly, precisely, and with more diversified manners. Here in this paper, we focus primarily on the PTMs of MRE11 and their roles in DNA response and repair, maintenance of genomic stability, as well as their association with diseases such as cancer.
Collapse
Affiliation(s)
- Ruiqing Lu
- School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; (R.L.); (Y.-N.J.)
| | - Han Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College; Kunming 650118, China;
| | - Yi-Nan Jiang
- School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; (R.L.); (Y.-N.J.)
| | - Zhao-Qi Wang
- Leibniz Institute on Aging–Fritz Lipmann Institute (FLI), 07745 Jena, Germany;
- Faculty of Biological Sciences, Friedrich-Schiller-University of Jena, 07745 Jena, Germany
| | - Litao Sun
- School of Public Health (Shenzhen), Sun Yat-Sen University, Shenzhen 518107, China
| | - Zhong-Wei Zhou
- School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; (R.L.); (Y.-N.J.)
| |
Collapse
|
9
|
Chen Y, Sun J, Ju Z, Wang ZQ, Li T. Nbs1-mediated DNA damage repair pathway regulates haematopoietic stem cell development and embryonic haematopoiesis. Cell Prolif 2021; 54:e12972. [PMID: 33586242 PMCID: PMC7941224 DOI: 10.1111/cpr.12972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/27/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022] Open
Abstract
Objectives DNA damages pose threats to haematopoietic stem cells (HSC) maintenance and haematopoietic system homeostasis. Quiescent HSCs in adult mouse bone marrow are resistant to DNA damage, while human umbilical cord blood‐derived proliferative HSCs are prone to cell death upon ionizing radiation. Murine embryonic HSCs proliferate in foetal livers and divide symmetrically to generate HSC pool. How murine embryonic HSCs respond to DNA damages is not well‐defined. Materials and methods Mice models with DNA repair molecule Nbs1 or Nbs1/p53 specifically deleted in embryonic HSCs were generated. FACS analysis, in vitro and in vivo HSC differentiation assays, qPCR, immunofluorescence and Western blotting were used to delineate roles of Nbs1‐p53 signaling in HSCs and haematopoietic progenitors. Results Nbs1 deficiency results in persistent DNA breaks in embryonic HSCs, compromises embryonic HSC development and finally results in mouse perinatal lethality. The persistent DNA breaks in Nbs1 deficient embryonic HSCs render cell cycle arrest, while driving a higher rate of cell death in haematopoietic progenitors. Although Nbs1 deficiency promotes Atm‐Chk2‐p53 axis activation in HSCs and their progenies, ablation of p53 in Nbs1 deficient HSCs accelerates embryonic lethality. Conclusions Our study discloses that DNA double‐strand repair molecule Nbs1 is essential in embryonic HSC development and haematopoiesis. Persistent DNA damages result in distinct cell fate in HSCs and haematopoietic progenitors. Nbs1 null HSCs tend to be maintained through cell cycle arrest, while Nbs1 null haematopoietic progenitors commit cell death. The discrepancies are mediated possibly by different magnitude of p53 signaling.
Collapse
Affiliation(s)
- Yu Chen
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Jie Sun
- Jiangsu Hansoh Pharmaceutical Group Co., Ltd., Lianyungang, China
| | - Zhenyu Ju
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany.,Faculty of Biology and Pharmacy, Friedrich-Schiller University of Jena, Jena, Germany
| | - Tangliang Li
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China.,State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,NHC Key Laboratory of Birth Defect for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| |
Collapse
|
10
|
Zhou ZW, Kirtay M, Schneble N, Yakoub G, Ding M, Rüdiger T, Siniuk K, Lu R, Jiang YN, Li TL, Kaether C, Barzilai A, Wang ZQ. NBS1 interacts with Notch signaling in neuronal homeostasis. Nucleic Acids Res 2020; 48:10924-10939. [PMID: 33010171 PMCID: PMC7641754 DOI: 10.1093/nar/gkaa716] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/03/2020] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
NBS1 is a critical component of the MRN (MRE11/RAD50/NBS1) complex, which regulates ATM- and ATR-mediated DNA damage response (DDR) pathways. Mutations in NBS1 cause the human genomic instability syndrome Nijmegen Breakage Syndrome (NBS), of which neuronal deficits, including microcephaly and intellectual disability, are classical hallmarks. Given its function in the DDR to ensure proper proliferation and prevent death of replicating cells, NBS1 is essential for life. Here we show that, unexpectedly, Nbs1 deletion is dispensable for postmitotic neurons, but compromises their arborization and migration due to dysregulated Notch signaling. We find that Nbs1 interacts with NICD-RBPJ, the effector of Notch signaling, and inhibits Notch activity. Genetic ablation or pharmaceutical inhibition of Notch signaling rescues the maturation and migration defects of Nbs1-deficient neurons in vitro and in vivo. Upregulation of Notch by Nbs1 deletion is independent of the key DDR downstream effector p53 and inactivation of each MRN component produces a different pattern of Notch activity and distinct neuronal defects. These data indicate that neuronal defects and aberrant Notch activity in Nbs1-deficient cells are unlikely to be a direct consequence of loss of MRN-mediated DDR function. This study discloses a novel function of NBS1 in crosstalk with the Notch pathway in neuron development.
Collapse
Affiliation(s)
- Zhong-Wei Zhou
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,School of Medicine (Shenzhen), Sun Yat-Sen University, Guangzhou, China
| | - Murat Kirtay
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Nadine Schneble
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - George Yakoub
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Mingmei Ding
- School of Medicine (Shenzhen), Sun Yat-Sen University, Guangzhou, China
| | - Tina Rüdiger
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Kanstantsin Siniuk
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Ruiqing Lu
- School of Medicine (Shenzhen), Sun Yat-Sen University, Guangzhou, China
| | - Yi-Nan Jiang
- School of Medicine (Shenzhen), Sun Yat-Sen University, Guangzhou, China
| | - Tang-Liang Li
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Christoph Kaether
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Ari Barzilai
- Department of Neurobiology, George S. Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.,Faculty of Biological Sciences, Friedrich-Schiller-University Jena, Jena, Germany
| |
Collapse
|
11
|
Watts LP, Natsume T, Saito Y, Garzon J, Dong Q, Boteva L, Gilbert N, Kanemaki MT, Hiraga SI, Donaldson AD. The RIF1-long splice variant promotes G1 phase 53BP1 nuclear bodies to protect against replication stress. eLife 2020; 9:e58020. [PMID: 33141022 PMCID: PMC7671687 DOI: 10.7554/elife.58020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 11/02/2020] [Indexed: 12/13/2022] Open
Abstract
Human cells lacking RIF1 are highly sensitive to replication inhibitors, but the reasons for this sensitivity have been enigmatic. Here, we show that RIF1 must be present both during replication stress and in the ensuing recovery period to promote cell survival. Of two isoforms produced by alternative splicing, we find that RIF1-Long alone can protect cells against replication inhibition, but RIF1-Short is incapable of mediating protection. Consistent with this isoform-specific role, RIF1-Long is required to promote the formation of the 53BP1 nuclear bodies that protect unrepaired damage sites in the G1 phase following replication stress. Overall, our observations show that RIF1 is needed at several cell cycle stages after replication insult, with the RIF1-Long isoform playing a specific role during the ensuing G1 phase in damage site protection.
Collapse
Affiliation(s)
- Lotte P Watts
- Institute of Medical Sciences, University of AberdeenAberdeenUnited Kingdom
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS)MishimaJapan
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI)MishimaJapan
| | - Yuichiro Saito
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS)MishimaJapan
| | - Javier Garzon
- Institute of Medical Sciences, University of AberdeenAberdeenUnited Kingdom
| | - Qianqian Dong
- Institute of Medical Sciences, University of AberdeenAberdeenUnited Kingdom
| | - Lora Boteva
- MRC Human Genetics Unit, The University of EdinburghEdinburghUnited Kingdom
| | - Nick Gilbert
- MRC Human Genetics Unit, The University of EdinburghEdinburghUnited Kingdom
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS)MishimaJapan
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI)MishimaJapan
| | - Shin-ichiro Hiraga
- Institute of Medical Sciences, University of AberdeenAberdeenUnited Kingdom
| | - Anne D Donaldson
- Institute of Medical Sciences, University of AberdeenAberdeenUnited Kingdom
| |
Collapse
|
12
|
Bennett LG, Wilkie AM, Antonopoulou E, Ceppi I, Sanchez A, Vernon EG, Gamble A, Myers KN, Collis SJ, Cejka P, Staples CJ. MRNIP is a replication fork protection factor. SCIENCE ADVANCES 2020; 6:eaba5974. [PMID: 32832601 PMCID: PMC7439443 DOI: 10.1126/sciadv.aba5974] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/28/2020] [Indexed: 05/04/2023]
Abstract
The remodeling of stalled replication forks to form four-way DNA junctions is an important component of the replication stress response. Nascent DNA at the regressed arms of these reversed forks is protected by RAD51 and the tumor suppressors BRCA1/2, and when this function is compromised, stalled forks undergo pathological MRE11-dependent degradation, leading to chromosomal instability. However, the mechanisms regulating MRE11 functions at reversed forks are currently unclear. Here, we identify the MRE11-binding protein MRNIP as a novel fork protection factor that directly binds to MRE11 and specifically represses its exonuclease activity. The loss of MRNIP results in impaired replication fork progression, MRE11 exonuclease-dependent degradation of reversed forks, persistence of underreplicated genomic regions, chemosensitivity, and chromosome instability. Our findings identify MRNIP as a novel regulator of MRE11 at reversed forks and provide evidence that regulation of specific MRE11 nuclease activities ensures protection of nascent DNA and thereby genome integrity.
Collapse
Affiliation(s)
- L. G. Bennett
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - A. M. Wilkie
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - E. Antonopoulou
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - I. Ceppi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
- Institute of Biochemistry, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - A. Sanchez
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
| | - E. G. Vernon
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - A. Gamble
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| | - K. N. Myers
- Sheffield Institute for Nucleic Acids, Department of Oncology and Metabolism, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - S. J. Collis
- Sheffield Institute for Nucleic Acids, Department of Oncology and Metabolism, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - P. Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
- Institute of Biochemistry, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - C. J. Staples
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor LL57 2UW, UK
| |
Collapse
|
13
|
Chang EYC, Tsai S, Aristizabal MJ, Wells JP, Coulombe Y, Busatto FF, Chan YA, Kumar A, Dan Zhu Y, Wang AYH, Fournier LA, Hieter P, Kobor MS, Masson JY, Stirling PC. MRE11-RAD50-NBS1 promotes Fanconi Anemia R-loop suppression at transcription-replication conflicts. Nat Commun 2019; 10:4265. [PMID: 31537797 PMCID: PMC6753070 DOI: 10.1038/s41467-019-12271-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 08/30/2019] [Indexed: 12/25/2022] Open
Abstract
Ectopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors including the MRE11-RAD50-NBS1 (MRN) complex. While MRN has been shown to promote R-loops at DNA double-strand breaks, we show that it suppresses R-loops and associated DNA damage at transcription-replication conflicts. This occurs through a non-nucleolytic function of MRE11 that is important for R-loop suppression by the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms at transcription-replication conflicts.
Collapse
Affiliation(s)
| | - Shuhe Tsai
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Maria J Aristizabal
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - James P Wells
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yan Coulombe
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Franciele F Busatto
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Yujia A Chan
- The Broad Institute of MIT and Harvard University, Cambridge, MA, 02142, USA
| | - Arun Kumar
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yi Dan Zhu
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | | | | | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada
| | - Michael S Kobor
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - Jean-Yves Masson
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada.
| |
Collapse
|
14
|
Nbn-Mre11 interaction is required for tumor suppression and genomic integrity. Proc Natl Acad Sci U S A 2019; 116:15178-15183. [PMID: 31285322 DOI: 10.1073/pnas.1905305116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We derived a mouse model in which a mutant form of Nbn/Nbs1mid8 (hereafter Nbnmid8) exhibits severely impaired binding to the Mre11-Rad50 core of the Mre11 complex. The Nbn mid8 allele was expressed exclusively in hematopoietic lineages (in Nbn -/mid8vav mice). Unlike Nbn flox/floxvav mice with Nbn deficiency in the bone marrow, Nbn -/mid8vav mice were viable. Nbn -/mid8vav mice hematopoiesis was profoundly defective, exhibiting reduced cellularity of thymus and bone marrow, and stage-specific blockage of B cell development. Within 6 mo, Nbn -/mid8 mice developed highly penetrant T cell leukemias. Nbn -/mid8vav leukemias recapitulated mutational features of human T cell acute lymphoblastic leukemia (T-ALL), containing mutations in NOTCH1, TP53, BCL6, BCOR, and IKZF1, suggesting that Nbn mid8 mice may provide a venue to examine the relationship between the Mre11 complex and oncogene activation in the hematopoietic compartment. Genomic analysis of Nbn -/mid8vav malignancies showed focal amplification of 9qA2, causing overexpression of MRE11 and CHK1 We propose that overexpression of MRE11 compensates for the metastable Mre11-Nbnmid8 interaction, and that selective pressure for overexpression reflects the essential role of Nbn in promoting assembly and activity of the Mre11 complex.
Collapse
|
15
|
Hamilton NA, Wendel BM, Weber EA, Courcelle CT, Courcelle J. RecBCD, SbcCD and ExoI process a substrate created by convergent replisomes to complete DNA replication. Mol Microbiol 2019; 111:1638-1651. [PMID: 30883946 DOI: 10.1111/mmi.14242] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2019] [Indexed: 12/11/2022]
Abstract
The accurate completion of DNA replication on the chromosome requires RecBCD and structure specific SbcCD and ExoI nucleases. However, the substrates and mechanism by which this reaction occurs remains unknown. Here we show that these completion enzymes operate on plasmid substrates containing two replisomes, but are not required for plasmids containing one replisome. Completion on the two-replisome plasmids requires RecBCD, but does not require RecA and no broken intermediates accumulate in its absence, indicating that the completion reaction occurs normally in the absence of any double-strand breaks. Further, similar to the chromosome, we show that when the normal completion reaction is prevented, an aberrant RecA-mediated recombination process leads to amplifications that drive most of the instabilities associated with the two-replisome substrates. The observations imply that the substrate SbcCD, ExoI and RecBCD act upon in vivo is created specifically by two convergent replisomes, and demonstrate that the function of RecBCD in completing replication is independent of double-strand break repair, and likely promotes joining of the strands of the convergent replication forks.
Collapse
Affiliation(s)
- Nicklas A Hamilton
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | - Brian M Wendel
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | - Emma A Weber
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | | | - Justin Courcelle
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| |
Collapse
|
16
|
MRE11 inhibition highlights a replication stress-dependent vulnerability of MYCN-driven tumors. Cell Death Dis 2018; 9:895. [PMID: 30166519 PMCID: PMC6117286 DOI: 10.1038/s41419-018-0924-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 12/12/2022]
Abstract
MRE11 is a component of the MRE11/RAD50/NBS1 (MRN) complex, whose activity is essential to control faithful DNA replication and to prevent accumulation of deleterious DNA double-strand breaks. In humans, hypomorphic mutations in these genes lead to DNA damage response (DDR)-defective and cancer-prone syndromes. Moreover, MRN complex dysfunction dramatically affects the nervous system, where MRE11 is required to restrain MYCN-dependent replication stress, during the rapid expansion of progenitor cells. MYCN activation, often due to genetic amplification, represents the driving oncogenic event for a number of human tumors, conferring bad prognosis and predicting very poor responses even to the most aggressive therapeutic protocols. This is prototypically exemplified by neuroblastoma, where MYCN amplification occurs in about 25% of the cases. Intriguingly, MRE11 is highly expressed and predicts bad prognosis in MYCN-amplified neuroblastoma. Due to the lack of direct means to target MYCN, we explored the possibility to trigger intolerable levels of replication stress-dependent DNA damage, by inhibiting MRE11 in MYCN-amplified preclinical models. Indeed, either MRE11 knockdown or its pharmacological inhibitor mirin induce accumulation of replication stress and DNA damage biomarkers in MYCN-amplified cells. The consequent DDR recruits p53 and promotes a p53-dependent cell death, as indicated by p53 loss- and gain-of-function experiments. Encapsulation of mirin in nanoparticles allowed its use on MYCN-amplified neuroblastoma xenografts in vivo, which resulted in a sharp impairment of tumor growth, associated with DDR activation, p53 accumulation, and cell death. Therefore, we propose that MRE11 inhibition might be an effective strategy to treat MYCN-amplified and p53 wild-type neuroblastoma, and suggest that targeting replication stress with appropriate tools should be further exploited to tackle MYCN-driven tumors.
Collapse
|
17
|
Interdependent and separable functions of Caenorhabditis elegans MRN-C complex members couple formation and repair of meiotic DSBs. Proc Natl Acad Sci U S A 2018; 115:E4443-E4452. [PMID: 29686104 DOI: 10.1073/pnas.1719029115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Faithful inheritance of genetic information through sexual reproduction relies on the formation of crossovers between homologous chromosomes during meiosis, which, in turn, relies on the formation and repair of numerous double-strand breaks (DSBs). As DSBs pose a potential threat to the genome, mechanisms that ensure timely and error-free DSB repair are crucial for successful meiosis. Here, we identify NBS-1, the Caenorhabditis elegans ortholog of the NBS1 (mutated in Nijmegen Breakage Syndrome) subunit of the conserved MRE11-RAD50-NBS1/Xrs2 (MRN) complex, as a key mediator of DSB repair via homologous recombination (HR) during meiosis. Loss of nbs-1 leads to severely reduced loading of recombinase RAD-51, ssDNA binding protein RPA, and pro-crossover factor COSA-1 during meiotic prophase progression; aggregated and fragmented chromosomes at the end of meiotic prophase; and 100% progeny lethality. These phenotypes reflect a role for NBS-1 in processing of meiotic DSBs for HR that is shared with its interacting partners MRE-11-RAD-50 and COM-1 (ortholog of Com1/Sae2/CtIP). Unexpectedly, in contrast to MRE-11 and RAD-50, NBS-1 is not required for meiotic DSB formation. Meiotic defects of the nbs-1 mutant are partially suppressed by abrogation of the nonhomologous end-joining (NHEJ) pathway, indicating a role for NBS-1 in antagonizing NHEJ during meiosis. Our data further reveal that NBS-1 and COM-1 play distinct roles in promoting HR and antagonizing NHEJ. We propose a model in which different components of the MRN-C complex work together to couple meiotic DSB formation with efficient and timely engagement of HR, thereby ensuring crossover formation and restoration of genome integrity before the meiotic divisions.
Collapse
|
18
|
SbcC-SbcD and ExoI process convergent forks to complete chromosome replication. Proc Natl Acad Sci U S A 2017; 115:349-354. [PMID: 29208713 DOI: 10.1073/pnas.1715960114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SbcC-SbcD are the bacterial orthologs of Mre11-Rad50, a nuclease complex essential for genome stability, normal development, and viability in mammals. In vitro, these enzymes degrade long DNA palindromic structures. When inactivated along with ExoI in Escherichia coli, or Sae2 in eukaryotes, palindromic amplifications arise and propagate in cells. However, long DNA palindromes are not normally found in bacterial or human genomes, leaving the cellular substrates and function of these enzymes unknown. Here, we show that during the completion of DNA replication, convergent replication forks form a palindrome-like structural intermediate that requires nucleolytic processing by SbcC-SbcD and ExoI before chromosome replication can be completed. Inactivation of these nucleases prevents completion from occurring, and under these conditions, cells maintain viability by shunting the reaction through an aberrant recombinational pathway that leads to amplifications and instability in this region. The results identify replication completion as an event critical to maintain genome integrity and cell viability, demonstrate SbcC-SbcD-ExoI acts before RecBCD and is required to initiate the completion reaction, and reveal how defects in completion result in genomic instability.
Collapse
|
19
|
Schuhwerk H, Bruhn C, Siniuk K, Min W, Erener S, Grigaravicius P, Krüger A, Ferrari E, Zubel T, Lazaro D, Monajembashi S, Kiesow K, Kroll T, Bürkle A, Mangerich A, Hottiger M, Wang ZQ. Kinetics of poly(ADP-ribosyl)ation, but not PARP1 itself, determines the cell fate in response to DNA damage in vitro and in vivo. Nucleic Acids Res 2017; 45:11174-11192. [PMID: 28977496 PMCID: PMC5737718 DOI: 10.1093/nar/gkx717] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022] Open
Abstract
One of the fastest cellular responses to genotoxic stress is the formation of poly(ADP-ribose) polymers (PAR) by poly(ADP-ribose)polymerase 1 (PARP1, or ARTD1). PARP1 and its enzymatic product PAR regulate diverse biological processes, such as DNA repair, chromatin remodeling, transcription and cell death. However, the inter-dependent function of the PARP1 protein and its enzymatic activity clouds the mechanism underlying the biological response. We generated a PARP1 knock-in mouse model carrying a point mutation in the catalytic domain of PARP1 (D993A), which impairs the kinetics of the PARP1 activity and the PAR chain complexity in vitro and in vivo, designated as hypo-PARylation. PARP1D993A/D993A mice and cells are viable and show no obvious abnormalities. Despite a mild defect in base excision repair (BER), this hypo-PARylation compromises the DNA damage response during DNA replication, leading to cell death or senescence. Strikingly, PARP1D993A/D993A mice are hypersensitive to alkylation in vivo, phenocopying the phenotype of PARP1 knockout mice. Our study thus unravels a novel regulatory mechanism, which could not be revealed by classical loss-of-function studies, on how PAR homeostasis, but not the PARP1 protein, protects cells and organisms from acute DNA damage.
Collapse
Affiliation(s)
- Harald Schuhwerk
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Christopher Bruhn
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Kanstantsin Siniuk
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Wookee Min
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Suheda Erener
- Department of Molecular Mechanisms of Disease, University of Zurich, CH-8057 Zurich, Switzerland
| | - Paulius Grigaravicius
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Annika Krüger
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRSCB), University of Konstanz, 78457 Konstanz, Germany
| | - Elena Ferrari
- Department of Molecular Mechanisms of Disease, University of Zurich, CH-8057 Zurich, Switzerland
| | - Tabea Zubel
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRSCB), University of Konstanz, 78457 Konstanz, Germany
| | - David Lazaro
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Shamci Monajembashi
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Kirstin Kiesow
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Torsten Kroll
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Alexander Bürkle
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Aswin Mangerich
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Michael Hottiger
- Department of Molecular Mechanisms of Disease, University of Zurich, CH-8057 Zurich, Switzerland
| | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz-Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany.,Faculty of Biology and Pharmacy, Friedrich Schiller University Jena, Germany
| |
Collapse
|
20
|
Klusmann I, Rodewald S, Müller L, Friedrich M, Wienken M, Li Y, Schulz-Heddergott R, Dobbelstein M. p53 Activity Results in DNA Replication Fork Processivity. Cell Rep 2017; 17:1845-1857. [PMID: 27829155 DOI: 10.1016/j.celrep.2016.10.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/03/2016] [Accepted: 10/12/2016] [Indexed: 12/18/2022] Open
Abstract
p53 induces cell death upon DNA damage, but this may not confer all of its tumor suppressor activity. We report that p53 activation enhances the processivity of DNA replication, as monitored by multi-label fiber assays, whereas removal of p53 reduces fork progression. This is observed in tumor-derived U2OS cells but also in murine embryonic fibroblasts with heterozygous or homozygous p53 deletion and in freshly isolated thymocytes from mice with differential p53 status. Mdm2, a p53-inducible gene product, similarly supports DNA replication even in p53-deficient cells, suggesting that sustained Mdm2-expression is at least one of the mechanisms allowing p53 to prevent replicative stress. Thus, p53 helps to protect the genome during S phase, by preventing the occurrence of stalled or collapsed replication forks. These results expand p53's tumor-suppressive functions, adding to the ex-post model (elimination of damaged cells) an ex-ante activity; i.e., the prevention of DNA damage during replication.
Collapse
Affiliation(s)
- Ina Klusmann
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Sabrina Rodewald
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Leonie Müller
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Mascha Friedrich
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Magdalena Wienken
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Yizhu Li
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Ramona Schulz-Heddergott
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, 37077 Göttingen, Germany.
| |
Collapse
|
21
|
Wang W, Zhang G, Yang J, Gu H, Ding L, Yu H, Yu M, Cui Q, Ji X, Li M. Digital gene expression profiling analysis of DNA repair pathways in colon cancer stem population of HT29 cells. Acta Biochim Biophys Sin (Shanghai) 2017; 49:90-100. [PMID: 27932392 DOI: 10.1093/abbs/gmw119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/28/2016] [Indexed: 02/06/2023] Open
Abstract
Cancer stem cells (CSCs) contribute to the relapse and development of new neoplasm lesions. While most available clinical approaches, such as chemical and radiation therapies, will kill the majority of cancer cells, they do not kill them all. Some resisting cells, like CSCs, are able to survive due to their excellent self-maintaining capabilities, even in challenging environments. In the present study, we investigated the mRNA level of DNA repair genes of colon CSCs from the HT29 cell line in response to single-strand damage and double-strand breaks, as well as the evident upregulation of key genes in base excision repair, mismatch repair, non-homologous end-joining, and homologous recombination pathways in these cells. Digital gene expression analysis identified upregulated genes in CD44+ HT29 cells that may play important roles in DNA repair. Our results reveal that colon CSCs bear efficient DNA repair abilities, which might explain the survival of colon CSCs after repeated chemical and radiation therapy.
Collapse
Affiliation(s)
- Wenxue Wang
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Guoxiu Zhang
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Jing Yang
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Huan Gu
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Lei Ding
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Haijing Yu
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Min Yu
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Qinghua Cui
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Xinglai Ji
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China
| | - Meizhang Li
- Laboratory of Biochemistry and Molecular Biology, School of Life Sciences, Yunnan University, Kunming 650091, China
| |
Collapse
|
22
|
Staples CJ, Barone G, Myers KN, Ganesh A, Gibbs-Seymour I, Patil AA, Beveridge RD, Daye C, Beniston R, Maslen S, Ahel I, Skehel JM, Collis SJ. MRNIP/C5orf45 Interacts with the MRN Complex and Contributes to the DNA Damage Response. Cell Rep 2016; 16:2565-2575. [PMID: 27568553 PMCID: PMC5014761 DOI: 10.1016/j.celrep.2016.07.087] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 05/25/2016] [Accepted: 07/27/2016] [Indexed: 11/27/2022] Open
Abstract
Through an RNAi-based screen for previously uncharacterized regulators of genome stability, we have identified the human protein C5orf45 as an important factor in preventing the accumulation of DNA damage in human cells. Here, we functionally characterize C5orf45 as a binding partner of the MRE11-RAD50-NBS1 (MRN) damage-sensing complex. Hence, we rename C5orf45 as MRNIP for MRN-interacting protein (MRNIP). We find that MRNIP is rapidly recruited to sites of DNA damage. Cells depleted of MRNIP display impaired chromatin loading of the MRN complex, resulting in reduced DNA end resection and defective ATM-mediated DNA damage signaling, a reduced ability to repair DNA breaks, and radiation sensitivity. Finally, we show that MRNIP phosphorylation on serine 115 leads to its nuclear localization, and this modification is required for MRNIP's role in promoting genome stability. Collectively, these data reveal that MRNIP is an important component of the human DNA damage response.
Collapse
Affiliation(s)
- Christopher J Staples
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Giancarlo Barone
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Katie N Myers
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Anil Ganesh
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Ian Gibbs-Seymour
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Abhijit A Patil
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Ryan D Beveridge
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Caroline Daye
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Richard Beniston
- Biological Mass Spectrometry Facility biOMICS, University of Sheffield, Brook Hill Road, Sheffield S3 7HF, UK
| | - Sarah Maslen
- Division of Cell Biology, Mass Spectrometry Group, The MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - J Mark Skehel
- Division of Cell Biology, Mass Spectrometry Group, The MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Spencer J Collis
- Sheffield Institute for Nucleic Acids (SInFoNiA), Department of Oncology and Metabolism, Academic Unit of Molecular Oncology, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK.
| |
Collapse
|
23
|
DNA Damage Response in Hematopoietic Stem Cell Ageing. GENOMICS PROTEOMICS & BIOINFORMATICS 2016; 14:147-154. [PMID: 27221660 PMCID: PMC4936660 DOI: 10.1016/j.gpb.2016.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/20/2016] [Accepted: 04/24/2016] [Indexed: 12/30/2022]
Abstract
Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity. Hematopoietic stem cells (HSCs) are the most primitive cell type in the hematopoietic system. They divide asymmetrically and give rise to daughter cells with HSC identity (self-renewal) and progenitor progenies (differentiation), which further proliferate and differentiate into full hematopoietic lineages. Mammalian ageing process is accompanied with abnormalities in the HSC self-renewal and differentiation. Transcriptional changes and epigenetic modulations have been implicated as the key regulators in HSC ageing process. The DNA damage response (DDR) in the cells involves an orchestrated signaling pathway, consisting of cell cycle regulation, cell death and senescence, transcriptional regulation, as well as chromatin remodeling. Recent studies employing DNA repair-deficient mouse models indicate that DDR could intrinsically and extrinsically regulate HSC maintenance and play important roles in tissue homeostasis of the hematopoietic system. In this review, we summarize the current understanding of how the DDR determines the HSC fates and finally contributes to organismal ageing.
Collapse
|
24
|
Huh MS, Ivanochko D, Hashem LE, Curtin M, Delorme M, Goodall E, Yan K, Picketts DJ. Stalled replication forks within heterochromatin require ATRX for protection. Cell Death Dis 2016; 7:e2220. [PMID: 27171262 PMCID: PMC4917659 DOI: 10.1038/cddis.2016.121] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/04/2016] [Accepted: 04/08/2016] [Indexed: 01/04/2023]
Abstract
Expansive growth of neural progenitor cells (NPCs) is a prerequisite to the temporal waves of neuronal differentiation that generate the six-layered neocortex, while also placing a heavy burden on proteins that regulate chromatin packaging and genome integrity. This problem is further reflected by the growing number of developmental disorders caused by mutations in chromatin regulators. ATRX gene mutations cause a severe intellectual disability disorder (α-thalassemia mental retardation X-linked (ATRX) syndrome; OMIM no. 301040), characterized by microcephaly, urogenital abnormalities and α-thalassemia. Although the ATRX protein is required for the maintenance of repetitive DNA within heterochromatin, how this translates to disease pathogenesis remain poorly understood and was a focus of this study. We demonstrate that Atrx(FoxG1Cre) forebrain-specific conditional knockout mice display poly(ADP-ribose) polymerase-1 (Parp-1) hyperactivation during neurogenesis and generate fewer late-born Cux1- and Brn2-positive neurons that accounts for the reduced cortical size. Moreover, DNA damage, induced Parp-1 and Atm activation is elevated in progenitor cells and contributes to their increased level of cell death. ATRX-null HeLa cells are similarly sensitive to hydroxyurea-induced replication stress, accumulate DNA damage and proliferate poorly. Impaired BRCA1-RAD51 colocalization and PARP-1 hyperactivation indicated that stalled replication forks are not efficiently protected. DNA fiber assays confirmed that MRE11 degradation of stalled replication forks was rampant in the absence of ATRX or DAXX. Indeed, fork degradation in ATRX-null cells could be attenuated by treatment with the MRE11 inhibitor mirin, or exacerbated by inhibiting PARP-1 activity. Taken together, these results suggest that ATRX is required to limit replication stress during cellular proliferation, whereas upregulation of PARP-1 activity functions as a compensatory mechanism to protect stalled forks, limiting genomic damage, and facilitating late-born neuron production.
Collapse
Affiliation(s)
- M S Huh
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - D Ivanochko
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - L E Hashem
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - M Curtin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - M Delorme
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - E Goodall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - K Yan
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - D J Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| |
Collapse
|
25
|
Petroni M, Sardina F, Heil C, Sahún-Roncero M, Colicchia V, Veschi V, Albini S, Fruci D, Ricci B, Soriani A, Di Marcotullio L, Screpanti I, Gulino A, Giannini G. The MRN complex is transcriptionally regulated by MYCN during neural cell proliferation to control replication stress. Cell Death Differ 2016; 23:197-206. [PMID: 26068589 PMCID: PMC4716299 DOI: 10.1038/cdd.2015.81] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 04/12/2015] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathogenesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.
Collapse
Affiliation(s)
- M Petroni
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - F Sardina
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - C Heil
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - M Sahún-Roncero
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - V Colicchia
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - V Veschi
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - S Albini
- Paediatric Haematology/Oncology Department, IRCCS, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - D Fruci
- Paediatric Haematology/Oncology Department, IRCCS, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - B Ricci
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - A Soriani
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - L Di Marcotullio
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - I Screpanti
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - A Gulino
- Department Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| | - G Giannini
- Istituto Pasteur-Fondazione Cenci Bolognetti, Deptartment of Molecular Medicine, University La Sapienza, 00161 Rome, Italy
| |
Collapse
|
26
|
Shimura T, Kobayashi J, Komatsu K, Kunugita N. Severe mitochondrial damage associated with low-dose radiation sensitivity in ATM- and NBS1-deficient cells. Cell Cycle 2016; 15:1099-107. [PMID: 26940879 PMCID: PMC4889229 DOI: 10.1080/15384101.2016.1156276] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 10/22/2022] Open
Abstract
Low-dose radiation risks remain unclear owing to a lack of sufficient studies. We previously reported that low-dose, long-term fractionated radiation (FR) with 0.01 or 0.05 Gy/fraction for 31 d inflicts oxidative stress in human fibroblasts due to excess levels of mitochondrial reactive oxygen species (ROS). To identify the small effects of low-dose radiation, we investigated how mitochondria respond to low-dose radiation in radiosensitive human ataxia telangiectasia mutated (ATM)- and Nijmegen breakage syndrome (NBS)1-deficient cell lines compared with corresponding cell lines expressing ATM and NBS1. Consistent with previous results in normal fibroblasts, low-dose, long-term FR increased mitochondrial mass and caused accumulation of mitochondrial ROS in ATM- and NBS1-complemented cell lines. Excess mitochondrial ROS resulted in mitochondrial damage that was in turn recognized by Parkin, leading to mitochondrial autophagy (mitophagy). In contrast, ATM- and NBS1-deficient cells showed defective induction of mitophagy after low-dose, long-term FR, leading to accumulation of abnormal mitochondria; this was determined by mitochondrial fragmentation and decreased mitochondrial membrane potential. Consequently, apoptosis was induced in ATM- and NBS1-deficient cells after low-dose, long-term FR. Antioxidant N-acetyl-L-cysteine was effective as a radioprotective agent against mitochondrial damage induced by low-dose, long-term FR among all cell lines, including radiosensitive cell lines. In conclusion, we demonstrated that mitochondria are target organelles of low-dose radiation. Mitochondrial response influences radiation sensitivity in human cells. Our findings provide new insights into cancer risk estimation associated with low-dose radiation exposure.
Collapse
Affiliation(s)
- Tsutomu Shimura
- a Department of Environmental Health , National Institute of Public Health , Wako , Saitama , Japan
| | - Junya Kobayashi
- b Department of Genome Dynamics , Radiation Biology Center, Kyoto University , Kyoto , Japan
| | - Kenshi Komatsu
- b Department of Genome Dynamics , Radiation Biology Center, Kyoto University , Kyoto , Japan
| | - Naoki Kunugita
- a Department of Environmental Health , National Institute of Public Health , Wako , Saitama , Japan
| |
Collapse
|
27
|
Burgess RC, Misteli T. Not All DDRs Are Created Equal: Non-Canonical DNA Damage Responses. Cell 2015; 162:944-7. [PMID: 26317463 DOI: 10.1016/j.cell.2015.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 10/23/2022]
Abstract
It is commonly assumed that there is a single canonical DNA damage response (DDR) that protects cells from various types of double-strand breaks and that its activation occurs via recognition of DNA ends by the DDR machinery. Recent work suggests that both assumptions may be oversimplifications. Here, we discuss several variations of the DDR in which the pathway is activated by diverse cellular events and/or generates distinct signaling outcomes. The existence of multiple non-canonical DDRs provides insights into how DNA damage is sensed and suggests a highly modular organization of the DDR.
Collapse
Affiliation(s)
- Rebecca C Burgess
- National Cancer Institute, NIH, Bethesda, MD 20892, USA; Department of Biological Sciences, School of the Sciences, Stevenson University, Stevenson, MD 21153, USA.
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| |
Collapse
|
28
|
Prochazkova J, Sakaguchi S, Owusu M, Mazouzi A, Wiedner M, Velimezi G, Moder M, Turchinovich G, Hladik A, Gurnhofer E, Hayday A, Behrens A, Knapp S, Kenner L, Ellmeier W, Loizou JI. DNA Repair Cofactors ATMIN and NBS1 Are Required to Suppress T Cell Activation. PLoS Genet 2015; 11:e1005645. [PMID: 26544571 PMCID: PMC4636180 DOI: 10.1371/journal.pgen.1005645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 10/12/2015] [Indexed: 12/11/2022] Open
Abstract
Proper development of the immune system is an intricate process dependent on many factors, including an intact DNA damage response. The DNA double-strand break signaling kinase ATM and its cofactor NBS1 are required during T cell development and for the maintenance of genomic stability. The role of a second ATM cofactor, ATMIN (also known as ASCIZ) in T cells is much less clear, and whether ATMIN and NBS1 function in synergy in T cells is unknown. Here, we investigate the roles of ATMIN and NBS1, either alone or in combination, using murine models. We show loss of NBS1 led to a developmental block at the double-positive stage of T cell development, as well as reduced TCRα recombination, that was unexpectedly neither exacerbated nor alleviated by concomitant loss of ATMIN. In contrast, loss of both ATMIN and NBS1 enhanced DNA damage that drove spontaneous peripheral T cell hyperactivation, proliferation as well as excessive production of proinflammatory cytokines and chemokines, leading to a highly inflammatory environment. Intriguingly, the disease causing T cells were largely proficient for both ATMIN and NBS1. In vivo this resulted in severe intestinal inflammation, colitis and premature death. Our findings reveal a novel model for an intestinal bowel disease phenotype that occurs upon combined loss of the DNA repair cofactors ATMIN and NBS1.
Collapse
Affiliation(s)
- Jana Prochazkova
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Shinya Sakaguchi
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria
| | - Michel Owusu
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Abdelghani Mazouzi
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Marc Wiedner
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Georgia Velimezi
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Martin Moder
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Gleb Turchinovich
- London Research Institute, Cancer Research UK, London, United Kingdom
| | - Anastasiya Hladik
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Elisabeth Gurnhofer
- Clinical Institute for Pathology, Medical University Vienna, Vienna, Austria
| | - Adrian Hayday
- London Research Institute, Cancer Research UK, London, United Kingdom
| | - Axel Behrens
- London Research Institute, Cancer Research UK, London, United Kingdom
| | - Sylvia Knapp
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Lukas Kenner
- Clinical Institute for Pathology, Medical University Vienna, Vienna, Austria
| | - Wilfried Ellmeier
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria
| | - Joanna I. Loizou
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| |
Collapse
|
29
|
Goto T, Kaida A, Miura M. Visualizing cell-cycle kinetics after hypoxia/reoxygenation in HeLa cells expressing fluorescent ubiquitination-based cell cycle indicator (Fucci). Exp Cell Res 2015; 339:389-96. [PMID: 26500111 DOI: 10.1016/j.yexcr.2015.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/17/2015] [Accepted: 10/19/2015] [Indexed: 01/19/2023]
Abstract
Hypoxia induces G1 arrest in many cancer cell types. Tumor cells are often exposed to hypoxia/reoxygenation, especially under acute hypoxic conditions in vivo. In this study, we investigated cell-cycle kinetics and clonogenic survival after hypoxia/reoxygenation in HeLa cells expressing fluorescent ubiquitination-based cell cycle indicator (Fucci). Hypoxic treatment halted cell-cycle progression during mid-S to G2 phase, as determined by the cell cycle-regulated E3 ligase activities of SCF(Skp2) and APC/C(Cdh1), which are regulators of the Fucci probes; however, the DNA content of the arrested cells was equivalent to that in G1 phase. After reoxygenation, time-lapse imaging and DNA content analysis revealed that all cells reached G2 phase, and that Fucci fluorescence was distinctly separated into two fractions 24h after reoxygenation: red cells that released from G2 arrest after repairing DNA double-strand breaks (DSBs) exhibited higher clonogenic survival, whereas most cells that stayed green contained many DSBs and exhibited lower survival. We conclude that hypoxia disrupts coordination of DNA synthesis and E3 ligase activities associated with cell-cycle progression, and that DSB repair could greatly influence cell-cycle kinetics and clonogenic survival after hypoxia/reoxygenation.
Collapse
Affiliation(s)
- Tatsuaki Goto
- Department of Oral Radiation Oncology, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Atsushi Kaida
- Department of Oral Radiation Oncology, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Masahiko Miura
- Department of Oral Radiation Oncology, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| |
Collapse
|
30
|
Rint1 inactivation triggers genomic instability, ER stress and autophagy inhibition in the brain. Cell Death Differ 2015; 23:454-68. [PMID: 26383973 DOI: 10.1038/cdd.2015.113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 06/30/2015] [Accepted: 07/08/2015] [Indexed: 11/08/2022] Open
Abstract
Endoplasmic reticulum (ER) stress, defective autophagy and genomic instability in the central nervous system are often associated with severe developmental defects and neurodegeneration. Here, we reveal the role played by Rint1 in these different biological pathways to ensure normal development of the central nervous system and to prevent neurodegeneration. We found that inactivation of Rint1 in neuroprogenitors led to death at birth. Depletion of Rint1 caused genomic instability due to chromosome fusion in dividing cells. Furthermore, Rint1 deletion in developing brain promotes the disruption of ER and Cis/Trans Golgi homeostasis in neurons, followed by ER-stress increase. Interestingly, Rint1 deficiency was also associated with the inhibition of the autophagosome clearance. Altogether, our findings highlight the crucial roles of Rint1 in vivo in genomic stability maintenance, as well as in prevention of ER stress and autophagy.
Collapse
|
31
|
Petroni M, Giannini G. A MYCN-MRN complex axis controls replication stress for the safe expansion of neuroprogenitor cells. Mol Cell Oncol 2015; 3:e1079673. [PMID: 27308604 DOI: 10.1080/23723556.2015.1079673] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
Abstract
DNA replication must be tightly regulated to ensure accurate duplication of the genome and its transfer to the daughter cells. When these regulatory mechanisms fail, replicative stress and DNA damage ensue, eventually leading to cell cycle inhibition or cell death. We have recently uncovered that MYCN-dependent expansion of neuroprogenitor cells is accompanied by replication stress, which is restrained by the MRN complex, a direct transcriptional target of the MYCN proto-oncogene.
Collapse
Affiliation(s)
| | - Giuseppe Giannini
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dept. Molecular Medicine, University La Sapienza , Rome, Italy
| |
Collapse
|
32
|
Directed Alternative Splicing in Nijmegen Breakage Syndrome: Proof of Principle Concerning Its Therapeutical Application. Mol Ther 2015; 24:117-24. [PMID: 26265251 DOI: 10.1038/mt.2015.144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/05/2015] [Indexed: 12/20/2022] Open
Abstract
Over 90% of patients with Nijmegen breakage syndrome (NBS), a hereditary cancer disorder, are homoallelic for a 5 bp deletion in the NBN gene involved in the cellular response to DNA damage. This hypomorphic mutation leads to a carboxy-terminal protein fragment, p70-nibrin, with some residual function. Average age at malignancy, typically lymphoma, is 9.7 years. NBS patients are hypersensitive to chemotherapeutic and radiotherapeutic treatments, thus prevention of cancer development is of particular importance. Expression of an internally deleted NBN protein, p80-nibrin, has been previously shown to be associated with a milder cellular phenotype and absence of cancer in a 62-year-old NBS patient. Here we show that cells from this patient, unlike other NBS patients, have DNA replication and origin firing rates comparable to control cells. We used here antisense oligonucleotides to enforce alternative splicing in NBS patient cells and efficiently generate the same internally deleted p80-nibrin protein. Injecting the same antisense sequences as morpholino oligomers (VivoMorpholinos) into the tail vein of a humanized NBS murine mouse model also led to efficient alternative splicing in vivo. Thus, proof of principle for the use of antisense oligonucleotides as a potential cancer prophylaxis has been demonstrated.
Collapse
|
33
|
Courcelle J, Wendel BM, Livingstone DD, Courcelle CT. RecBCD is required to complete chromosomal replication: Implications for double-strand break frequencies and repair mechanisms. DNA Repair (Amst) 2015; 32:86-95. [PMID: 26003632 PMCID: PMC4522357 DOI: 10.1016/j.dnarep.2015.04.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Several aspects of the mechanism of homologous double-strand break repair remain unclear. Although intensive efforts have focused on how recombination reactions initiate, far less is known about the molecular events that follow. Based upon biochemical studies, current models propose that RecBCD processes double-strand ends and loads RecA to initiate recombinational repair. However, recent studies have shown that RecBCD plays a critical role in completing replication events on the chromosome through a mechanism that does not involve RecA or recombination. Here, we examine several studies, both early and recent, that suggest RecBCD also operates late in the recombination process - after initiation, strand invasion, and crossover resolution have occurred. Similar to its role in completing replication, we propose a model in which RecBCD is required to resect and resolve the DNA synthesis associated with homologous recombination at the point where the missing sequences on the broken molecule have been restored. We explain how the impaired ability to complete chromosome replication in recBC and recD mutants is likely to account for the loss of viability and genome instability in these mutants, and conclude that spontaneous double-strand breaks and replication fork collapse occur far less frequently than previously speculated.
Collapse
Affiliation(s)
- Justin Courcelle
- Department of Biology, Portland State University, Portland, OR 97201, United States.
| | - Brian M Wendel
- Department of Biology, Portland State University, Portland, OR 97201, United States
| | - Dena D Livingstone
- Department of Biology, Portland State University, Portland, OR 97201, United States
| | - Charmain T Courcelle
- Department of Biology, Portland State University, Portland, OR 97201, United States
| |
Collapse
|
34
|
Rein K, Yanez DA, Terré B, Palenzuela L, Aivio S, Wei K, Edelmann W, Stark JM, Stracker TH. EXO1 is critical for embryogenesis and the DNA damage response in mice with a hypomorphic Nbs1 allele. Nucleic Acids Res 2015; 43:7371-87. [PMID: 26160886 PMCID: PMC4551929 DOI: 10.1093/nar/gkv691] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/25/2015] [Indexed: 12/15/2022] Open
Abstract
The maintenance of genome stability is critical for the suppression of diverse human pathologies that include developmental disorders, premature aging, infertility and predisposition to cancer. The DNA damage response (DDR) orchestrates the appropriate cellular responses following the detection of lesions to prevent genomic instability. The MRE11 complex is a sensor of DNA double strand breaks (DSBs) and plays key roles in multiple aspects of the DDR, including DNA end resection that is critical for signaling and DNA repair. The MRE11 complex has been shown to function both upstream and in concert with the 5′-3′ exonuclease EXO1 in DNA resection, but it remains unclear to what extent EXO1 influences DSB responses independently of the MRE11 complex. Here we examine the genetic relationship of the MRE11 complex and EXO1 during mammalian development and in response to DNA damage. Deletion of Exo1 in mice expressing a hypomorphic allele of Nbs1 leads to severe developmental impairment, embryonic death and chromosomal instability. While EXO1 plays a minimal role in normal cells, its loss strongly influences DNA replication, DNA repair, checkpoint signaling and damage sensitivity in NBS1 hypomorphic cells. Collectively, our results establish a key role for EXO1 in modulating the severity of hypomorphic MRE11 complex mutations.
Collapse
Affiliation(s)
- Katrin Rein
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona 08028, Spain
| | - Diana A Yanez
- Department of Radiation Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Berta Terré
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona 08028, Spain
| | - Lluís Palenzuela
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona 08028, Spain
| | - Suvi Aivio
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona 08028, Spain
| | - Kaichun Wei
- Albert Einstein College of Medicine, Department of Cell Biology, Bronx, NY 10461, USA
| | - Winfried Edelmann
- Albert Einstein College of Medicine, Department of Cell Biology, Bronx, NY 10461, USA
| | - Jeremy M Stark
- Department of Radiation Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona 08028, Spain
| |
Collapse
|
35
|
Millet R, Jolinon N, Nguyen XN, Berger G, Cimarelli A, Greco A, Bertrand P, Odenthal M, Büning H, Salvetti A. Impact of the MRN Complex on Adeno-Associated Virus Integration and Replication during Coinfection with Herpes Simplex Virus 1. J Virol 2015; 89:6824-34. [PMID: 25903339 PMCID: PMC4468484 DOI: 10.1128/jvi.00171-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/13/2015] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Adeno-associated virus (AAV) is a helper-dependent parvovirus that requires coinfection with adenovirus (AdV) or herpes simplex virus 1 (HSV-1) to replicate. In the absence of the helper virus, AAV can persist in an episomal or integrated form. Previous studies have analyzed the DNA damage response (DDR) induced upon AAV replication to understand how it controls AAV replication. In particular, it was shown that the Mre11-Rad50-Nbs1 (MRN) complex, a major player of the DDR induced by double-stranded DNA breaks and stalled replication forks, could negatively regulate AdV and AAV replication during coinfection. In contrast, MRN favors HSV-1 replication and is recruited to AAV replication compartments that are induced in the presence of HSV-1. In this study, we examined the role of MRN during AAV replication induced by HSV-1. Our results indicated that knockdown of MRN significantly reduced AAV DNA replication after coinfection with wild-type (wt) HSV-1 or HSV-1 with the polymerase deleted. This effect was specific to wt AAV, since it did not occur with recombinant AAV vectors. Positive regulation of AAV replication by MRN was dependent on its DNA tethering activity but did not require its nuclease activities. Importantly, knockdown of MRN also negatively regulated AAV integration within the human AAVS1 site, both in the presence and in the absence of HSV-1. Altogether, this work identifies a new function of MRN during integration of the AAV genome and demonstrates that this DNA repair complex positively regulates AAV replication in the presence of HSV-1. IMPORTANCE Viral DNA genomes trigger a DNA damage response (DDR), which can be either detrimental or beneficial for virus replication. Adeno-associated virus (AAV) is a defective parvovirus that requires the help of an unrelated virus such as adenovirus (AdV) or herpes simplex virus 1 (HSV-1) for productive replication. Previous studies have demonstrated that the cellular Mre11-Rad50-Nbs1 (MRN) complex, a sensor and regulator of the DDR, negatively regulates AAV replication during coinfection with AdV, which counteracts this effect by inactivating the complex. Here, we demonstrate that MRN positively regulates AAV replication during coinfection with HSV-1. Importantly, our study also indicates that MRN also favors integration of AAV genomes within the human AAVS1 site. Altogether, this work indicates that MRN differentially regulates AAV replication depending on the helper virus which is present and identifies a new function of this DNA repair complex during AAV integration.
Collapse
Affiliation(s)
- Rachel Millet
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | - Nelly Jolinon
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France
| | - Xuan-Nhi Nguyen
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | - Gregory Berger
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France
| | - Andrea Cimarelli
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | - Anna Greco
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | - Pascale Bertrand
- INSERM U967, CEA, Université Paris Diderot, Université Paris Sud, CEA DSV, Institut de Radiobiologie Moléculaire et Cellulaire, Fontenay-aux-Roses, France
| | - Margarete Odenthal
- Institute for Pathology, University Hospital of Cologne, Cologne, Germany Center for Molecular Medicine of Cologne, University of Cologne, Cologne, Germany
| | - Hildegard Büning
- Center for Molecular Medicine of Cologne, University of Cologne, Cologne, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany German Center for Infection Research, Bonn-Cologne Partner Site, Bonn-Cologne, Germany
| | - Anna Salvetti
- International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| |
Collapse
|
36
|
Kar A, Kaur M, Ghosh T, Khan MM, Sharma A, Shekhar R, Varshney A, Saxena S. RPA70 depletion induces hSSB1/2-INTS3 complex to initiate ATR signaling. Nucleic Acids Res 2015; 43:4962-74. [PMID: 25916848 PMCID: PMC4446429 DOI: 10.1093/nar/gkv369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/08/2015] [Indexed: 01/12/2023] Open
Abstract
The primary eukaryotic single-stranded DNA-binding protein, Replication protein A (RPA), binds to single-stranded DNA at the sites of DNA damage and recruits the apical checkpoint kinase, ATR via its partner protein, ATRIP. It has been demonstrated that absence of RPA incapacitates the ATR-mediated checkpoint response. We report that in the absence of RPA, human single-stranded DNA-binding protein 1 (hSSB1) and its partner protein INTS3 form sub-nuclear foci, associate with the ATR-ATRIP complex and recruit it to the sites of genomic stress. The ATRIP foci formed after RPA depletion are abrogated in the absence of INTS3, establishing that hSSB-INTS3 complex recruits the ATR-ATRIP checkpoint complex to the sites of genomic stress. Depletion of homologs hSSB1/2 and INTS3 in RPA-deficient cells attenuates Chk1 phosphorylation, indicating that the cells are debilitated in responding to stress. We have identified that TopBP1 and the Rad9-Rad1-Hus1 complex are essential for the alternate mode of ATR activation. In summation, we report that the single-stranded DNA-binding protein complex, hSSB1/2-INTS3 can recruit the checkpoint complex to initiate ATR signaling.
Collapse
Affiliation(s)
- Ananya Kar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Manpreet Kaur
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Tanushree Ghosh
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Md Muntaz Khan
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Aparna Sharma
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Ritu Shekhar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Akhil Varshney
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Sandeep Saxena
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110067, India
| |
Collapse
|
37
|
Shimura T, Kobayashi J, Komatsu K, Kunugita N. DNA damage signaling guards against perturbation of cyclin D1 expression triggered by low-dose long-term fractionated radiation. Oncogenesis 2014; 3:e132. [PMID: 25486524 PMCID: PMC4275562 DOI: 10.1038/oncsis.2014.48] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/24/2014] [Accepted: 11/02/2014] [Indexed: 12/20/2022] Open
Abstract
Cyclin D1 expression is precisely controlled during cell-cycle progression. However, repeated exposure to low-dose fractionated radiation (FR) abrogates cell cycle-dependent cyclin D1 degradation by constitutive activation of AKT survival signaling in normal human fibroblasts. The resulting abnormal nuclear cyclin D1 accumulation induces defects in DNA replication and resulting DNA double-strand breaks, and is associated with induction of genomic instability in low-dose irradiated cells. Here, we investigated the role of DNA damage signaling against such perturbed cell-cycle control of cyclin D1 expression. Nuclear cyclin D1 accumulation was induced within 7 days after low-dose FR (0.01 Gy or 0.05 Gy per fraction) in ATM-deficient cells (AT5BIVA), but appeared later in AT5BIVA cells harboring human ATM cDNA. Thus, ATM prevents abnormal nuclear cyclin D1 accumulation at early time points after low-dose FR. We further demonstrated that ATM-mediated downregulation of protein phosphatase 2A activity caused activation of the AKT/cyclin D1 pathway after long-term FR. Perturbation of cyclin D1 expression induced Rad51 foci that indicate homologous recombination repair (HRR) in control cells, while ATM- and NBS1-deficient cells (GM7166) failed to induce Rad51 foci after long-term low-dose FR. After 21 days of FR, NBS1- and ATM-deficient cells showed a decrease in nuclear cyclin D1-positive cells, and an increase in apoptotic cells. Similarly, inhibition of ATM with KU55933 abrogated nuclear cyclin D1 accumulation by induction of apoptosis in ATM-complemented cells exposed to low-dose FR. In conclusion, we here demonstrate that ATM is involved in controlling cyclin D1 levels after low-dose FR. DNA damage signaling mitigates the harmful effects of low-dose long-term FR by suppression of cell death induced by perturbation of cyclin D1 expression.
Collapse
Affiliation(s)
- T Shimura
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - J Kobayashi
- Department of Genome Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - K Komatsu
- Department of Genome Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - N Kunugita
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| |
Collapse
|
38
|
Bruhn C, Kroll T, Wang ZQ. Systematic characterization of cell cycle phase-dependent protein dynamics and pathway activities by high-content microscopy-assisted cell cycle phenotyping. GENOMICS PROTEOMICS & BIOINFORMATICS 2014; 12:255-65. [PMID: 25458086 PMCID: PMC4411490 DOI: 10.1016/j.gpb.2014.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/07/2014] [Indexed: 11/22/2022]
Abstract
Cell cycle progression is coordinated with metabolism, signaling and other complex cellular functions. The investigation of cellular processes in a cell cycle stage-dependent manner is often the subject of modern molecular and cell biological research. Cell cycle synchronization and immunostaining of cell cycle markers facilitate such analysis, but are limited in use due to unphysiological experimental stress, cell type dependence and often low flexibility. Here, we describe high-content microscopy-assisted cell cycle phenotyping (hiMAC), which integrates high-resolution cell cycle profiling of asynchronous cell populations with immunofluorescence microscopy. hiMAC is compatible with cell types from any species and allows for statistically powerful, unbiased, simultaneous analysis of protein interactions, modifications and subcellular localization at all cell cycle stages within a single sample. For illustration, we provide a hiMAC analysis pipeline tailored to study DNA damage response and genomic instability using a 3–4-day protocol, which can be adjusted to any other cell cycle stage-dependent analysis.
Collapse
Affiliation(s)
- Christopher Bruhn
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), 07745 Jena, Germany
| | - Torsten Kroll
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), 07745 Jena, Germany
| | - Zhao-Qi Wang
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), 07745 Jena, Germany; Faculty of Biology and Pharmacy, Friedrich Schiller University of Jena, 07745 Jena, Germany.
| |
Collapse
|
39
|
The MRE11 complex: An important source of stress relief. Exp Cell Res 2014; 329:162-9. [DOI: 10.1016/j.yexcr.2014.10.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/01/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
|
40
|
Skvortsov S, Debbage P, Lukas P, Skvortsova I. Crosstalk between DNA repair and cancer stem cell (CSC) associated intracellular pathways. Semin Cancer Biol 2014; 31:36-42. [PMID: 24954010 DOI: 10.1016/j.semcancer.2014.06.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/09/2014] [Indexed: 01/08/2023]
Abstract
DNA damaging agents (ionizing radiation and chemotherapeutics) are considered as most effective in cancer treatment. However, there is a subpopulation of carcinoma cells within the tumour demonstrating resistance to DNA damaging treatment approaches. It is suggested that limited tumour response to this kind of therapy can be associated with specific molecular properties of carcinoma stem cells (CSCs) representing the most refractory cell subpopulation. This review article presents novel data about molecular features of CSCs underlying DNA damage response and related intracellular signalling.
Collapse
Affiliation(s)
- Sergej Skvortsov
- Department of Therapeutic Radiology and Oncology, Innsbruck Medical University, Innsbruck, Austria.
| | - Paul Debbage
- Department of Anatomy, Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | - Peter Lukas
- Department of Therapeutic Radiology and Oncology, Innsbruck Medical University, Innsbruck, Austria
| | - Ira Skvortsova
- Department of Therapeutic Radiology and Oncology, Innsbruck Medical University, Innsbruck, Austria
| |
Collapse
|
41
|
Yata K, Bleuyard JY, Nakato R, Ralf C, Katou Y, Schwab RA, Niedzwiedz W, Shirahige K, Esashi F. BRCA2 coordinates the activities of cell-cycle kinases to promote genome stability. Cell Rep 2014; 7:1547-1559. [PMID: 24835992 PMCID: PMC4062933 DOI: 10.1016/j.celrep.2014.04.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 03/11/2014] [Accepted: 04/13/2014] [Indexed: 02/06/2023] Open
Abstract
Numerous human genome instability syndromes, including cancer, are closely associated with events arising from malfunction of the essential recombinase Rad51. However, little is known about how Rad51 is dynamically regulated in human cells. Here, we show that the breast cancer susceptibility protein BRCA2, a key Rad51 binding partner, coordinates the activity of the central cell-cycle drivers CDKs and Plk1 to promote Rad51-mediated genome stability control. The soluble nuclear fraction of BRCA2 binds Plk1 directly in a cell-cycle- and CDK-dependent manner and acts as a molecular platform to facilitate Plk1-mediated Rad51 phosphorylation. This phosphorylation is important for enhancing the association of Rad51 with stressed replication forks, which in turn protects the genomic integrity of proliferating human cells. This study reveals an elaborate but highly organized molecular interplay between Rad51 regulators and has significant implications for understanding tumorigenesis and therapeutic resistance in patients with BRCA2 deficiency.
Collapse
Affiliation(s)
- Keiko Yata
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Jean-Yves Bleuyard
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Ryuichiro Nakato
- Research Center for Epigenetic Disease, Graduate School of Frontier Sciences, University of Tokyo, Tokyo 113-0032, Japan; CREST, Japan Science and Technology Agency (JST), K's Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Christine Ralf
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Yuki Katou
- Research Center for Epigenetic Disease, Graduate School of Frontier Sciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Rebekka A Schwab
- The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Wojciech Niedzwiedz
- The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Graduate School of Frontier Sciences, University of Tokyo, Tokyo 113-0032, Japan; CREST, Japan Science and Technology Agency (JST), K's Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Fumiko Esashi
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| |
Collapse
|
42
|
Productive replication of human papillomavirus 31 requires DNA repair factor Nbs1. J Virol 2014; 88:8528-44. [PMID: 24850735 DOI: 10.1128/jvi.00517-14] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Activation of the ATM (ataxia telangiectasia-mutated kinase)-dependent DNA damage response (DDR) is necessary for productive replication of human papillomavirus 31 (HPV31). We previously found that DNA repair and homologous recombination (HR) factors localize to sites of HPV replication, suggesting that ATM activity is required to recruit factors to viral genomes that can productively replicate viral DNA in a recombination-dependent manner. The Mre11-Rad50-Nbs1 (MRN) complex is an essential component of the DDR that is necessary for ATM-mediated HR repair and localizes to HPV DNA foci. In this study, we demonstrate that the HPV E7 protein is sufficient to increase levels of the MRN complex and also interacts with MRN components. We have found that Nbs1 depletion blocks productive viral replication and results in decreased localization of Mre11, Rad50, and the principal HR factor Rad51 to HPV DNA foci upon differentiation. Nbs1 contributes to the DDR by acting as an upstream activator of ATM in response to double-strand DNA breaks (DSBs) and as a downstream effector of ATM activity in the intra-S-phase checkpoint. We have found that phosphorylation of ATM and its downstream target Chk2, as well as SMC1 (structural maintenance of chromosome 1), is maintained upon Nbs1 knockdown in differentiating cells. Given that ATM and Chk2 are required for productive replication, our results suggest that Nbs1 contributes to viral replication outside its role as an ATM activator, potentially through ensuring localization of DNA repair factors to viral genomes that are necessary for efficient productive replication. IMPORTANCE The mechanisms that regulate human papillomavirus (HPV) replication during the viral life cycle are not well understood. Our finding that Nbs1 is necessary for productive replication even in the presence of ATM (ataxia telangiectasia-mutated kinase) and Chk2 phosphorylation offers evidence that Nbs1 contributes to viral replication downstream of facilitating ATM activation. Nbs1 is required for the recruitment of Mre11 and Rad50 to viral genomes, suggesting that the MRN complex plays a direct role in facilitating productive viral replication, potentially through the processing of substrates that are recognized by the key homologous recombination (HR) factor Rad51. The discovery that E7 increases levels of MRN components, and MRN complex formation, identifies a novel role for E7 in facilitating productive replication. Our study not only identifies DNA repair factors necessary for HPV replication but also provides a deeper understanding of how HPV utilizes the DNA damage response to regulate viral replication.
Collapse
|