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Bossaert M, Moreno AT, Peixoto A, Pillaire MJ, Chanut P, Frit P, Calsou P, Loparo JJ, Britton S. Identification of the main barriers to Ku accumulation in chromatin. Cell Rep 2024; 43:114538. [PMID: 39058590 DOI: 10.1016/j.celrep.2024.114538] [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: 01/11/2024] [Revised: 05/29/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024] Open
Abstract
Repair of DNA double-strand breaks by the non-homologous end-joining pathway is initiated by the binding of Ku to DNA ends. Multiple Ku proteins load onto linear DNAs in vitro. However, in cells, Ku loading is limited to ∼1-2 molecules per DNA end. The mechanisms enforcing this limit are currently unclear. Here, we show that the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs), but not its protein kinase activity, is required to prevent excessive Ku entry into chromatin. Ku accumulation is further restricted by two mechanisms: a neddylation/FBXL12-dependent process that actively removes loaded Ku molecules throughout the cell cycle and a CtIP/ATM-dependent mechanism that operates in S phase. Finally, we demonstrate that the misregulation of Ku loading leads to impaired transcription in the vicinity of DNA ends. Together, our data shed light on the multiple mechanisms operating to prevent Ku from invading chromatin and interfering with other DNA transactions.
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Affiliation(s)
- Madeleine Bossaert
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018
| | - Andrew T Moreno
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Antonio Peixoto
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018
| | - Marie-Jeanne Pillaire
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018
| | - Pauline Chanut
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018
| | - Philippe Frit
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018.
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
| | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France; Equipe Labéllisée la Ligue contre le Cancer 2018.
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2
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Bossaert M, Moreno A, Peixoto A, Pillaire MJ, Chanut P, Frit P, Calsou P, Loparo JJ, Britton S. Identification of the main barriers to Ku accumulation in chromatin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.574002. [PMID: 38260538 PMCID: PMC10802386 DOI: 10.1101/2024.01.03.574002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Repair of DNA double strand breaks by the non-homologous end-joining pathway is initiated by the binding of Ku to DNA ends. Given its high affinity for ends, multiple Ku proteins load onto linear DNAs in vitro. However, in cells, Ku loading is limited to ~1-2 molecules per DNA end. The mechanisms enforcing this limit are currently unknown. Here we show that the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs), but not its protein kinase activity, is required to prevent excessive Ku entry into chromatin. Ku accumulation is further restricted by two mechanisms: a neddylation/FBXL12-dependent process which actively removes loaded Ku molecules throughout the cell cycle and a CtIP/ATM-dependent mechanism which operates in S-phase. Finally, we demonstrate that the misregulation of Ku loading leads to impaired transcription in the vicinity of DNA ends. Together our data shed light on the multiple layers of coordinated mechanisms operating to prevent Ku from invading chromatin and interfering with other DNA transactions.
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Affiliation(s)
- Madeleine Bossaert
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Andrew Moreno
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Antonio Peixoto
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Marie-Jeanne Pillaire
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Pauline Chanut
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Philippe Frit
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
| | - Joseph John Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe labélisée la Ligue contre le Cancer 2018
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3
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Kefala Stavridi A, Gontier A, Morin V, Frit P, Ropars V, Barboule N, Racca C, Jonchhe S, Morten M, Andreani J, Rak A, Legrand P, Bourand-Plantefol A, Hardwick S, Chirgadze D, Davey P, De Oliveira TM, Rothenberg E, Britton S, Calsou P, Blundell T, Varela P, Chaplin A, Charbonnier JB. Structural and functional basis of inositol hexaphosphate stimulation of NHEJ through stabilization of Ku-XLF interaction. Nucleic Acids Res 2023; 51:11732-11747. [PMID: 37870477 PMCID: PMC10682503 DOI: 10.1093/nar/gkad863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 10/24/2023] Open
Abstract
The classical Non-Homologous End Joining (c-NHEJ) pathway is the predominant process in mammals for repairing endogenous, accidental or programmed DNA Double-Strand Breaks. c-NHEJ is regulated by several accessory factors, post-translational modifications, endogenous chemical agents and metabolites. The metabolite inositol-hexaphosphate (IP6) stimulates c-NHEJ by interacting with the Ku70-Ku80 heterodimer (Ku). We report cryo-EM structures of apo- and DNA-bound Ku in complex with IP6, at 3.5 Å and 2.74 Å resolutions respectively, and an X-ray crystallography structure of a Ku in complex with DNA and IP6 at 3.7 Å. The Ku-IP6 interaction is mediated predominantly via salt bridges at the interface of the Ku70 and Ku80 subunits. This interaction is distant from the DNA, DNA-PKcs, APLF and PAXX binding sites and in close proximity to XLF binding site. Biophysical experiments show that IP6 binding increases the thermal stability of Ku by 2°C in a DNA-dependent manner, stabilizes Ku on DNA and enhances XLF affinity for Ku. In cells, selected mutagenesis of the IP6 binding pocket reduces both Ku accrual at damaged sites and XLF enrolment in the NHEJ complex, which translate into a lower end-joining efficiency. Thus, this study defines the molecular bases of the IP6 metabolite stimulatory effect on the c-NHEJ repair activity.
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Affiliation(s)
- Antonia Kefala Stavridi
- Heartand Lung Research Institute, University of Cambridge, Biomedical Campus, Papworth Road, Trumpington, Cambridge CB2 0BB, UK
| | - Amandine Gontier
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Vincent Morin
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Philippe Frit
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Nadia Barboule
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Carine Racca
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Sagun Jonchhe
- NYU Langone Medical Center, 450 East 29th Street, NY, NY, USA York University, USA
| | - Michael J Morten
- NYU Langone Medical Center, 450 East 29th Street, NY, NY, USA York University, USA
| | - Jessica Andreani
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Alexey Rak
- Structure-Design-Informatics, Sanofi R&D, Vitry sur Seine, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, France
| | - Alexa Bourand-Plantefol
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Steven W Hardwick
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Dimitri Y Chirgadze
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Paul Davey
- Oncology, R&D, AstraZeneca, Cambridge, UK
| | | | - Eli Rothenberg
- NYU Langone Medical Center, 450 East 29th Street, NY, NY, USA York University, USA
| | - Sebastien Britton
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France
| | - Tom L Blundell
- Heartand Lung Research Institute, University of Cambridge, Biomedical Campus, Papworth Road, Trumpington, Cambridge CB2 0BB, UK
| | - Paloma F Varela
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Amanda K Chaplin
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Jean-Baptiste Charbonnier
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Univ.Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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4
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Seif-El-Dahan M, Kefala-Stavridi A, Frit P, Hardwick SW, Chirgadze DY, Maia De Oliviera T, Britton S, Barboule N, Bossaert M, Pandurangan AP, Meek K, Blundell TL, Ropars V, Calsou P, Charbonnier JB, Chaplin AK. PAXX binding to the NHEJ machinery explains functional redundancy with XLF. SCIENCE ADVANCES 2023; 9:eadg2834. [PMID: 37256950 PMCID: PMC10413649 DOI: 10.1126/sciadv.adg2834] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/03/2023] [Indexed: 06/02/2023]
Abstract
Nonhomologous end joining is a critical mechanism that repairs DNA double-strand breaks in human cells. In this work, we address the structural and functional role of the accessory protein PAXX [paralog of x-ray repair cross-complementing protein 4 (XRCC4) and XRCC4-like factor (XLF)] in this mechanism. Here, we report high-resolution cryo-electron microscopy (cryo-EM) and x-ray crystallography structures of the PAXX C-terminal Ku-binding motif bound to Ku70/80 and cryo-EM structures of PAXX bound to two alternate DNA-dependent protein kinase (DNA-PK) end-bridging dimers, mediated by either Ku80 or XLF. We identify residues critical for the Ku70/PAXX interaction in vitro and in cells. We demonstrate that PAXX and XLF can bind simultaneously to the Ku heterodimer and act as structural bridges in alternate forms of DNA-PK dimers. Last, we show that engagement of both proteins provides a complementary advantage for DNA end synapsis and end joining in cells.
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Affiliation(s)
- Murielle Seif-El-Dahan
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Antonia Kefala-Stavridi
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Philippe Frit
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Steven W. Hardwick
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Dima Y. Chirgadze
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | | | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Nadia Barboule
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Madeleine Bossaert
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Arun Prasad Pandurangan
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Tom L. Blundell
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Jean-Baptiste Charbonnier
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Amanda K. Chaplin
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
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5
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Zhu Y, Liu Z, Gui L, Yun W, Mao C, Deng R, Yao Y, Yu Q, Feng J, Ma H, Bao W. Inhibition of CXorf56 promotes PARP inhibitor-induced cytotoxicity in triple-negative breast cancer. NPJ Breast Cancer 2023; 9:34. [PMID: 37156759 PMCID: PMC10167262 DOI: 10.1038/s41523-023-00540-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
Poly(ADP-ribose) polymerase inhibitors (PARPis) induce DNA lesions that preferentially kill homologous recombination (HR)-deficient breast cancers induced by BRCA mutations, which exhibit a low incidence in breast cancer, thereby limiting the benefits of PARPis. Additionally, breast cancer cells, particularly triple-negative breast cancer (TNBC) cells, exhibit HR and PARPi resistance. Therefore, targets must be identified for inducing HR deficiency and sensitizing cancer cells to PARPis. Here, we reveal that CXorf56 protein increased HR repair in TNBC cells by interacting with the Ku70 DNA-binding domain, reducing Ku70 recruitment and promoting RPA32, BRCA2, and RAD51 recruitment to sites of DNA damage. Knockdown of CXorf56 protein suppressed HR in TNBC cells, specifically during the S and G2 phases, and increased cell sensitivity to olaparib in vitro and in vivo. Clinically, CXorf56 protein was upregulated in TNBC tissues and associated with aggressive clinicopathological characteristics and poor survival. All these findings indicate that treatment designed to inhibit CXorf56 protein in TNBC combined with PARPis may overcome drug resistance and expand the application of PARPis to patients with non-BRCA mutantion.
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Affiliation(s)
- Ying Zhu
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Zhixian Liu
- Department of Pharmacy, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Liang Gui
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Wen Yun
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Changfei Mao
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Rong Deng
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Yufeng Yao
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Qiao Yu
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China
| | - Jifeng Feng
- Department of General Surgery, Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, China.
| | - Hongxia Ma
- Department of Epidemiology, Center for Global Health, School of Public Health, Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.
| | - Wei Bao
- Department of Pathology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
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6
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Richardson C, Kelsh RN, J. Richardson R. New advances in CRISPR/Cas-mediated precise gene-editing techniques. Dis Model Mech 2023; 16:dmm049874. [PMID: 36847161 PMCID: PMC10003097 DOI: 10.1242/dmm.049874] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Over the past decade, CRISPR/Cas-based gene editing has become a powerful tool for generating mutations in a variety of model organisms, from Escherichia coli to zebrafish, rodents and large mammals. CRISPR/Cas-based gene editing effectively generates insertions or deletions (indels), which allow for rapid gene disruption. However, a large proportion of human genetic diseases are caused by single-base-pair substitutions, which result in more subtle alterations to protein function, and which require more complex and precise editing to recreate in model systems. Precise genome editing (PGE) methods, however, typically have efficiencies of less than a tenth of those that generate less-specific indels, and so there has been a great deal of effort to improve PGE efficiency. Such optimisations include optimal guide RNA and mutation-bearing donor DNA template design, modulation of DNA repair pathways that underpin how edits result from Cas-induced cuts, and the development of Cas9 fusion proteins that introduce edits via alternative mechanisms. In this Review, we provide an overview of the recent progress in optimising PGE methods and their potential for generating models of human genetic disease.
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Affiliation(s)
- Chris Richardson
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Robert N. Kelsh
- Department of Life Sciences, University of Bath, Bath BA2 7AY, UK
| | - Rebecca J. Richardson
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
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7
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Shridharan RV, Kalakuntla N, Chirmule N, Tiwari B. The Happy Hopping of Transposons: The Origins of V(D)J Recombination in Adaptive Immunity. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.836066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Nearly 50% of the human genome is derived from transposable elements (TEs). Though dysregulated transposons are deleterious to humans and can lead to diseases, co-opted transposons play an important role in generating alternative or new DNA sequence combinations to perform novel cellular functions. The appearance of an adaptive immune system in jawed vertebrates, wherein the somatic rearrangement of T and B cells generates a repertoire of antibodies and receptors, is underpinned by Class II TEs. This review follows the evolution of recombination activation genes (RAGs), components of adaptive immunity, from TEs, focusing on the structural and mechanistic similarities between RAG recombinases and DNA transposases. As evolution occurred from a transposon precursor, DNA transposases developed a more targeted and constrained mechanism of mobilization. As DNA repair is integral to transposition and recombination, we note key similarities and differences in the choice of DNA repair pathways following these processes. Understanding the regulation of V(D)J recombination from its evolutionary origins may help future research to specifically target RAG proteins to rectify diseases associated with immune dysregulation.
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8
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Hu C, Wallace N. Beta HPV Deregulates Double-Strand Break Repair. Viruses 2022; 14:v14050948. [PMID: 35632690 PMCID: PMC9146468 DOI: 10.3390/v14050948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 02/04/2023] Open
Abstract
Beta human papillomavirus (beta HPV) infections are common in adults. Certain types of beta HPVs are associated with nonmelanoma skin cancer (NMSC) in immunocompromised individuals. However, whether beta HPV infections promote NMSC in the immunocompetent population is unclear. They have been hypothesized to increase genomic instability stemming from ultraviolet light exposure by disrupting DNA damage responses. Implicit in this hypothesis is that the virus encodes one or more proteins that impair DNA repair signaling. Fluorescence-based reporters, next-generation sequencing, and animal models have been used to test this primarily in cells expressing beta HPV E6/E7. Of the two, beta HPV E6 appears to have the greatest ability to increase UV mutagenesis, by attenuating two major double-strand break (DSB) repair pathways, homologous recombination, and non-homologous end-joining. Here, we review this dysregulation of DSB repair and emerging approaches that can be used to further these efforts.
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9
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Singh JK, Smith R, Rother MB, de Groot AJL, Wiegant WW, Vreeken K, D’Augustin O, Kim RQ, Qian H, Krawczyk PM, González-Prieto R, Vertegaal ACO, Lamers M, Huet S, van Attikum H. Zinc finger protein ZNF384 is an adaptor of Ku to DNA during classical non-homologous end-joining. Nat Commun 2021; 12:6560. [PMID: 34772923 PMCID: PMC8589989 DOI: 10.1038/s41467-021-26691-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/19/2021] [Indexed: 12/14/2022] Open
Abstract
DNA double-strand breaks (DSBs) are among the most deleterious types of DNA damage as they can lead to mutations and chromosomal rearrangements, which underlie cancer development. Classical non-homologous end-joining (cNHEJ) is the dominant pathway for DSB repair in human cells, involving the DNA-binding proteins XRCC6 (Ku70) and XRCC5 (Ku80). Other DNA-binding proteins such as Zinc Finger (ZnF) domain-containing proteins have also been implicated in DNA repair, but their role in cNHEJ remained elusive. Here we show that ZNF384, a member of the C2H2 family of ZnF proteins, binds DNA ends in vitro and is recruited to DSBs in vivo. ZNF384 recruitment requires the poly(ADP-ribosyl) polymerase 1 (PARP1)-dependent expansion of damaged chromatin, followed by binding of its C2H2 motifs to the exposed DNA. Moreover, ZNF384 interacts with Ku70/Ku80 via its N-terminus, thereby promoting Ku70/Ku80 assembly and the accrual of downstream cNHEJ factors, including APLF and XRCC4/LIG4, for efficient repair at DSBs. Altogether, our data suggest that ZNF384 acts as a 'Ku-adaptor' that binds damaged DNA and Ku70/Ku80 to facilitate the build-up of a cNHEJ repairosome, highlighting a role for ZNF384 in DSB repair and genome maintenance.
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Affiliation(s)
- Jenny Kaur Singh
- grid.10419.3d0000000089452978Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Rebecca Smith
- grid.410368.80000 0001 2191 9284Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes)—UMR 6290, BIOSIT–UMS3480, F-35000 Rennes, France
| | - Magdalena B. Rother
- grid.10419.3d0000000089452978Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Anton J. L. de Groot
- grid.10419.3d0000000089452978Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Wouter W. Wiegant
- grid.10419.3d0000000089452978Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Kees Vreeken
- grid.10419.3d0000000089452978Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ostiane D’Augustin
- grid.410368.80000 0001 2191 9284Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes)—UMR 6290, BIOSIT–UMS3480, F-35000 Rennes, France ,grid.457349.80000 0004 0623 0579Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, F-92265 Fontenay-aux-Roses, France
| | - Robbert Q. Kim
- grid.10419.3d0000000089452978Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Haibin Qian
- grid.16872.3a0000 0004 0435 165XDepartment of Medical Biology, Amsterdam University Medical Centers (location AMC), Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Przemek M. Krawczyk
- grid.16872.3a0000 0004 0435 165XDepartment of Medical Biology, Amsterdam University Medical Centers (location AMC), Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Román González-Prieto
- grid.16872.3a0000 0004 0435 165XDepartment of Medical Biology, Amsterdam University Medical Centers (location AMC), Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Alfred C. O. Vertegaal
- grid.16872.3a0000 0004 0435 165XDepartment of Medical Biology, Amsterdam University Medical Centers (location AMC), Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Meindert Lamers
- grid.16872.3a0000 0004 0435 165XDepartment of Medical Biology, Amsterdam University Medical Centers (location AMC), Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Sébastien Huet
- grid.410368.80000 0001 2191 9284Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes)—UMR 6290, BIOSIT–UMS3480, F-35000 Rennes, France ,grid.440891.00000 0001 1931 4817Institut Universitaire de France, F-75000 Paris, France
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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10
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Aricthota S, Haldar D. DDK/Hsk1 phosphorylates and targets fission yeast histone deacetylase Hst4 for degradation to stabilize stalled DNA replication forks. eLife 2021; 10:70787. [PMID: 34608864 PMCID: PMC8565929 DOI: 10.7554/elife.70787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/01/2021] [Indexed: 01/01/2023] Open
Abstract
In eukaryotes, paused replication forks are prone to collapse, which leads to genomic instability, a hallmark of cancer. Dbf4-dependent kinase (DDK)/Hsk1Cdc7 is a conserved replication initiator kinase with conflicting roles in replication stress response. Here, we show that fission yeast DDK/Hsk1 phosphorylates sirtuin, Hst4 upon replication stress at C-terminal serine residues. Phosphorylation of Hst4 by DDK marks it for degradation via the ubiquitin ligase SCFpof3. Phosphorylation-defective hst4 mutant (4SA-hst4) displays defective recovery from replication stress, faulty fork restart, slow S-phase progression and decreased viability. The highly conserved fork protection complex (FPC) stabilizes stalled replication forks. We found that the recruitment of FPC components, Swi1 and Mcl1 to the chromatin is compromised in the 4SA-hst4 mutant, although whole cell levels increased. These defects are dependent upon H3K56ac and independent of intra S-phase checkpoint activation. Finally, we show conservation of H3K56ac-dependent regulation of Timeless, Tipin, and And-1 in human cells. We propose that degradation of Hst4 via DDK increases H3K56ac, changing the chromatin state in the vicinity of stalled forks facilitating recruitment and function of FPC. Overall, this study identified a crucial role of DDK and FPC in the regulation of replication stress response with implications in cancer therapeutics.
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Affiliation(s)
- Shalini Aricthota
- Laboratory of Chromatin Biology and Epigenetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Devyani Haldar
- Laboratory of Chromatin Biology and Epigenetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
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11
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Chen Y, Jiang T, Zhang H, Gou X, Han C, Wang J, Chen AT, Ma J, Liu J, Chen Z, Jing X, Lei H, Wang Z, Bao Y, Baqri M, Zhu Y, Bindra RS, Hansen JE, Dou J, Huang C, Zhou J. LRRC31 inhibits DNA repair and sensitizes breast cancer brain metastasis to radiation therapy. Nat Cell Biol 2020; 22:1276-1285. [PMID: 33005030 PMCID: PMC7962994 DOI: 10.1038/s41556-020-00586-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/28/2020] [Indexed: 12/27/2022]
Abstract
Breast cancer brain metastasis (BCBM) is a devastating disease. Radiation therapy remains the mainstay for treatment of this disease. Unfortunately, its efficacy is limited by the dose that can be safely applied. One promising approach to overcoming this limitation is to sensitize BCBMs to radiation by inhibiting their ability to repair DNA damage. Here, we report a DNA repair suppressor, leucine-rich repeat-containing protein 31 (LRRC31), that was identified through a genome-wide CRISPR screen. We found that overexpression of LRRC31 suppresses DNA repair and sensitizes BCBMs to radiation. Mechanistically, LRRC31 interacts with Ku70/Ku80 and the ataxia telangiectasia mutated and RAD3-related (ATR) at the protein level, resulting in inhibition of DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) recruitment and activation, and disruption of the MutS homologue 2 (MSH2)-ATR module. We demonstrate that targeted delivery of the LRRC31 gene via nanoparticles improves the survival of tumour-bearing mice after irradiation. Collectively, our study suggests LRRC31 as a major DNA repair suppressor that can be targeted for cancer radiosensitizing therapy.
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Affiliation(s)
- Yanke Chen
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Ting Jiang
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hongyi Zhang
- Department of Neurosurgery, Yale University, New Haven, CT, USA.,Department of Microbiology and Immunology, School of Medicine, Jinan University, Guangzhou, China
| | - Xingchun Gou
- Department of Neurosurgery, Yale University, New Haven, CT, USA.,Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Cong Han
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jianhui Wang
- Department of Pathology, Yale University, New Haven, CT, USA
| | - Ann T Chen
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jun Ma
- Department of Radiology in the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jun Liu
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Zeming Chen
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Xintao Jing
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hong Lei
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Zhenzhen Wang
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Youmei Bao
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Mehdi Baqri
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Yong Zhu
- School of Public Health, Yale University, New Haven, CT, USA
| | - Ranjit S Bindra
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - James E Hansen
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Jun Dou
- Department of Pathogenic Biology and Immunology, School of Medicine, Southeast University, Nanjing, China
| | - Chen Huang
- Department of Cell Biology and Genetics, Xi'an Jiaotong University, Xi'an, Shaanxi, China. .,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
| | - Jiangbing Zhou
- Department of Neurosurgery, Yale University, New Haven, CT, USA. .,Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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12
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Investigation of gene-gene interactions in cardiac traits and serum fatty acid levels in the LURIC Health Study. PLoS One 2020; 15:e0238304. [PMID: 32915819 PMCID: PMC7485803 DOI: 10.1371/journal.pone.0238304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 08/13/2020] [Indexed: 01/25/2023] Open
Abstract
Epistasis analysis elucidates the effects of gene-gene interactions (G×G) between multiple loci for complex traits. However, the large computational demands and the high multiple testing burden impede their discoveries. Here, we illustrate the utilization of two methods, main effect filtering based on individual GWAS results and biological knowledge-based modeling through Biofilter software, to reduce the number of interactions tested among single nucleotide polymorphisms (SNPs) for 15 cardiac-related traits and 14 fatty acids. We performed interaction analyses using the two filtering methods, adjusting for age, sex, body mass index (BMI), waist-hip ratio, and the first three principal components from genetic data, among 2,824 samples from the Ludwigshafen Risk and Cardiovascular (LURIC) Health Study. Using Biofilter, one interaction nearly met Bonferroni significance: an interaction between rs7735781 in XRCC4 and rs10804247 in XRCC5 was identified for venous thrombosis with a Bonferroni-adjusted likelihood ratio test (LRT) p: 0.0627. A total of 57 interactions were identified from main effect filtering for the cardiac traits G×G (10) and fatty acids G×G (47) at Bonferroni-adjusted LRT p < 0.05. For cardiac traits, the top interaction involved SNPs rs1383819 in SNTG1 and rs1493939 (138kb from 5’ of SAMD12) with Bonferroni-adjusted LRT p: 0.0228 which was significantly associated with history of arterial hypertension. For fatty acids, the top interaction between rs4839193 in KCND3 and rs10829717 in LOC107984002 with Bonferroni-adjusted LRT p: 2.28×10−5 was associated with 9-trans 12-trans octadecanoic acid, an omega-6 trans fatty acid. The model inflation factor for the interactions under different filtering methods was evaluated from the standard median and the linear regression approach. Here, we applied filtering approaches to identify numerous genetic interactions related to cardiac-related outcomes as potential targets for therapy. The approaches described offer ways to detect epistasis in the complex traits and to improve precision medicine capability.
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13
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Hu C, Bugbee T, Gamez M, Wallace NA. Beta Human Papillomavirus 8E6 Attenuates Non-Homologous End Joining by Hindering DNA-PKcs Activity. Cancers (Basel) 2020; 12:cancers12092356. [PMID: 32825402 PMCID: PMC7564021 DOI: 10.3390/cancers12092356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/15/2020] [Accepted: 08/18/2020] [Indexed: 12/20/2022] Open
Abstract
Cutaneous viral infections occur in a background of near continual exposure to environmental genotoxins, like UV radiation in sunlight. Failure to repair damaged DNA is an established driver of tumorigenesis and substantial cellular resources are devoted to repairing DNA lesions. Beta-human papillomaviruses (β-HPVs) attenuate DNA repair signaling. However, their role in human disease is unclear. Some have proposed that β-HPV promotes tumorigenesis, while others suggest that β-HPV protects against skin cancer. Most of the molecular evidence that β-HPV impairs DNA repair has been gained via characterization of the E6 protein from β-HPV 8 (β-HPV 8E6). Moreover, β-HPV 8E6 hinders DNA repair by binding and destabilizing p300, a transcription factor for multiple DNA repair genes. By reducing p300 availability, β-HPV 8E6 attenuates a major double strand DNA break (DSB) repair pathway, homologous recombination. Here, β-HPV 8E6 impairs another DSB repair pathway, non-homologous end joining (NHEJ). Specifically, β-HPV 8E6 acts by attenuating DNA-dependent protein kinase (DNA-PK) activity, a critical NHEJ kinase. This includes DNA-PK activation and the downstream of steps in the pathway associated with DNA-PK activity. Notably, β-HPV 8E6 inhibits NHEJ through p300 dependent and independent means. Together, these data expand the known genome destabilizing capabilities of β-HPV 8E6.
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Affiliation(s)
- Changkun Hu
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.H.); (T.B.)
| | - Taylor Bugbee
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.H.); (T.B.)
| | - Monica Gamez
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol BS1 3NY, UK;
| | - Nicholas A. Wallace
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA; (C.H.); (T.B.)
- Correspondence:
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14
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Vítor AC, Huertas P, Legube G, de Almeida SF. Studying DNA Double-Strand Break Repair: An Ever-Growing Toolbox. Front Mol Biosci 2020; 7:24. [PMID: 32154266 PMCID: PMC7047327 DOI: 10.3389/fmolb.2020.00024] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/04/2020] [Indexed: 12/29/2022] Open
Abstract
To ward off against the catastrophic consequences of persistent DNA double-strand breaks (DSBs), eukaryotic cells have developed a set of complex signaling networks that detect these DNA lesions, orchestrate cell cycle checkpoints and ultimately lead to their repair. Collectively, these signaling networks comprise the DNA damage response (DDR). The current knowledge of the molecular determinants and mechanistic details of the DDR owes greatly to the continuous development of ground-breaking experimental tools that couple the controlled induction of DSBs at distinct genomic positions with assays and reporters to investigate DNA repair pathways, their impact on other DNA-templated processes and the specific contribution of the chromatin environment. In this review, we present these tools, discuss their pros and cons and illustrate their contribution to our current understanding of the DDR.
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Affiliation(s)
- Alexandra C Vítor
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Pablo Huertas
- Department of Genetics, University of Seville, Seville, Spain.,Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Sérgio F de Almeida
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
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15
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Zhou Z, Lu H, Zhu S, Gomaa A, Chen Z, Yan J, Washington K, El-Rifai W, Dang C, Peng D. Activation of EGFR-DNA-PKcs pathway by IGFBP2 protects esophageal adenocarcinoma cells from acidic bile salts-induced DNA damage. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:13. [PMID: 30626422 PMCID: PMC6327430 DOI: 10.1186/s13046-018-1021-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/26/2018] [Indexed: 12/26/2022]
Abstract
Background The incidence of esophageal adenocarcinoma (EAC) is rising rapidly in the US and Western countries. The development of Barrett’s esophagus (BE) and its progression to EAC have been linked to chronic gastroesophageal reflux disease (GERD). Exposure of BE and EAC cells to acidic bile salts (ABS) in GERD conditions induces high levels of oxidative stress and DNA damage. In this study, we investigated the role of insulin-like growth factor binding protein 2 (IGFBP2) in regulating ABS-induced DNA double-strand breaks. Methods Real-time RT-PCR, western blot, immunohistochemistry, immunofluorescence, co-immunoprecipitation, flow cytometry, and cycloheximide (CHX) chase assays were used in this study. To mimic GERD conditions, a cocktail of acidic bile salts (pH 4) was used in 2D and 3D organotypic culture models. Overexpression and knockdown of IGFBP2 in EAC cells were established to examine the functional and mechanistic roles of IGFBP2 in ABS-induced DNA damage. Results Our results demonstrated high levels of IGFBP2 mRNA and protein in EAC cell lines as compared to precancerous Barrett’s cell lines, and IGFBP2 is frequently overexpressed in EACs (31/57). Treatment of EAC cells with ABS, to mimic GERD conditions, induced high levels of IGFBP2 expression. Knocking down endogenous IGFBP2 in FLO1 cells (with constitutive high levels of IGFBP2) led to a significant increase in DNA double-strand breaks and apoptosis, following transient exposure to ABS. On the other hand, overexpression of exogenous IGFBP2 in OE33 cells (with low endogenous levels of IGFBP2) had a protective effect against ABS-induced double-strand breaks and apoptosis. We found that IGFBP2 is required for ABS-induced nuclear accumulation and phosphorylation of EGFR and DNA-PKcs, which are necessary for DNA damage repair activity. Using co-immunoprecipitation assay, we detected co-localization of IGFBP2 with EGFR and DNA-PKcs, following acidic bile salts treatment. We further demonstrated, using cycloheximide chase assay, that IGFBP2 promotes EGFR protein stability in response to ABS exposure. Conclusions IGFBP2 protects EAC cells against ABS-induced DNA damage and apoptosis through stabilization and activation of EGFR - DNA-PKcs signaling axis. Electronic supplementary material The online version of this article (10.1186/s13046-018-1021-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhangjian Zhou
- Department of Surgical Oncology, the First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta W. Road, Xi'an, 710061, Shaanxi, China.,Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA
| | - Heng Lu
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA
| | - Shoumin Zhu
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA
| | - Ahmed Gomaa
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA
| | - Zheng Chen
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA
| | - Jin Yan
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA.,Department of Gastroenterology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Kay Washington
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Wael El-Rifai
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA.,Department of Veterans Affairs, Miami Healthcare System, Miami, FL, USA
| | - Chengxue Dang
- Department of Surgical Oncology, the First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta W. Road, Xi'an, 710061, Shaanxi, China.
| | - Dunfa Peng
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA. .,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, 33136-1015, USA.
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16
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Amiri Moghani AR, Sharma MK, Matsumoto Y. In cellulo phosphorylation of DNA double-strand break repair protein XRCC4 on Ser260 by DNA-PK. JOURNAL OF RADIATION RESEARCH 2018; 59:700-708. [PMID: 30247612 PMCID: PMC6251426 DOI: 10.1093/jrr/rry072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Indexed: 05/16/2023]
Abstract
XRCC4 is one of the core factors for DNA double-strand break (DSB) repair through non-homologous end joining (NHEJ). XRCC4 is phosphorylated by DNA-dependent protein kinase (DNA-PK), with Ser260 and Ser320 (Ser318 in the alternatively spliced form) being the major phosphorylation sites in vitro. It was recently reported that Ser320 is phosphorylated by DNA-PK in response to DNA damage; however, it is currently unclear whether Ser260 is phosphorylated in cellulo in response to DNA damage. Herein, we generated an antibody against XRCC4 phosphorylated on Ser260 and examined its phosphorylation status via Western blotting. XRCC4 Ser260 phosphorylation increased after irradiation with 30-300 Gy of γ-rays and was suppressed by DNA-PK inhibitor but not by ATM inhibitor. Moreover, XRCC4 Ser260 phosphorylation decreased in DNA-PKcs-deficient cells. These observations indicate that XRCC4 Ser260 is phosphorylated by DNA-PK in cellulo. The XRCC4S260A mutant reversed the high radiosensitivity of XRCC4-deficient M10 cells to a similar level to that of wild-type XRCC4. However, the clonogenic survival of cells expressing the XRCC4S260A mutant was slightly but significantly lower than that of those expressing wild-type XRCC4. In addition, XRCC4S260A-expressing cells displayed a significantly greater number of γ-H2AX foci than XRCC4WT-expressing cells 4 h after 1 Gy irradiation and without irradiation. The present results suggest a potential role of XRCC4 Ser260 phosphorylation by DNA-PK in DSB repair.
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Affiliation(s)
- Ali Reza Amiri Moghani
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1–30, Ookayama, Meguro-ku, Tokyo, Japan
| | - Mukesh Kumar Sharma
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1–30, Ookayama, Meguro-ku, Tokyo, Japan
- Department of Zoology, SPC Government College, Ajmer, Rajasthan, India
| | - Yoshihisa Matsumoto
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1–30, Ookayama, Meguro-ku, Tokyo, Japan
- Corresponding author. Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1–30, Ookayama, Meguro-ku, Tokyo 152-8550, Japan. Tel/Fax: +81-0-3-5734-3703;
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17
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Funck T, Barnkob MB, Holm N, Ohm-Laursen L, Mehlum CS, Möller S, Barington T. Nucleotide Composition of Human Ig Nontemplated Regions Depends on Trimming of the Flanking Gene Segments, and Terminal Deoxynucleotidyl Transferase Favors Adding Cytosine, Not Guanosine, in Most VDJ Rearrangements. THE JOURNAL OF IMMUNOLOGY 2018; 201:1765-1774. [PMID: 30097530 DOI: 10.4049/jimmunol.1800100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 07/05/2018] [Indexed: 01/12/2023]
Abstract
The formation of nontemplated (N) regions during Ig gene rearrangement is a major contributor to Ab diversity. To gain insights into the mechanisms behind this, we studied the nucleotide composition of N regions within 29,962 unique human VHDJH rearrangements and 8728 unique human DJH rearrangements containing exactly one identifiable D gene segment and thus two N regions, N1 and N2. We found a distinct decreasing content of cytosine (C) and increasing content of guanine (G) across each N region, suggesting that N regions are typically generated by concatenation of two 3' overhangs synthesized by addition of nucleoside triphosphates with a preference for dCTP. This challenges the general assumption that the terminal deoxynucleotidyl transferase favors dGTP in vivo. Furthermore, we found that the G and C gradients depended strongly on whether the germline gene segments were trimmed or not. Our data show that C-enriched N addition preferentially happens at trimmed 3' ends of VH, D, and JH gene segments, indicating a dependency of the transferase mechanism upon the nuclease mechanism.
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Affiliation(s)
- Tina Funck
- Department of Clinical Biochemistry, Zealand University Hospital, Roskilde 4000, Denmark.,Department of Clinical Immunology, Odense University Hospital, Odense 5000, Denmark
| | - Mike Bogetofte Barnkob
- Department of Clinical Immunology, Odense University Hospital, Odense 5000, Denmark.,Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxfordshire OX3 9DS, United Kingdom
| | - Nanna Holm
- Department of Clinical Immunology, Odense University Hospital, Odense 5000, Denmark
| | - Line Ohm-Laursen
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, United Kingdom
| | - Camilla Slot Mehlum
- Department of Otorhinolaryngology-Head and Neck Surgery, Odense University Hospital, Odense 5000, Denmark
| | - Sören Möller
- OPEN, Odense Patient Data Explorative Network, Odense University Hospital, Odense 5000, Denmark; and.,Clinical Department, University of Southern Denmark, Odense 5000, Denmark
| | - Torben Barington
- Department of Clinical Immunology, Odense University Hospital, Odense 5000, Denmark; .,Clinical Department, University of Southern Denmark, Odense 5000, Denmark
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18
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UHRF1 depletion sensitizes retinoblastoma cells to chemotherapeutic drugs via downregulation of XRCC4. Cell Death Dis 2018; 9:164. [PMID: 29415984 PMCID: PMC5833858 DOI: 10.1038/s41419-017-0203-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
UHRF1 (ubiquitin-like with PHD and ring finger domains 1) is highly expressed in various human cancers including retinoblastoma, and associated with tumor-promoting effects such as inhibition of apoptosis and high proliferation. However, the molecular mechanisms underlying tumor-promoting functions of UHRF1 in retinoblastoma still remain elusive. Here, we show that stable knockdown of UHRF1 renders retinoblastoma cells sensitized to conventional chemotherapeutic drugs such as etoposide and camptothecin, resulting in enhanced DNA damage and apoptotic cell death. We found that UHRF1-depleted retinoblastoma cells can recognize DNA damages normally but have markedly low expression of XRCC4 (X-ray repair cross complementing 4) among the components of nonhomologous end-joining (NHEJ) repair complex. Conversely, overexpression of UHRF1 increased the XRCC4 expression and stable knockdown of XRCC4 sensitized retinoblastoma cells to etoposide treatment, suggesting that XRCC4 is a key mediator for the drug sensitivity upon UHRF1 depletion in retinoblastoma cells. Consistent with the findings, chromatin association of DNA ligase IV in response to acute DNA damage was found to be significantly reduced in UHRF1-depleted retinoblastoma cells and functional complementation for XRCC4 in UHRF1-depleted cells attenuated the drug sensitivity, demonstrating that XRCC4 downregulation in UHRF1-depleted cells impaired DNA repair and consequently induced robust apoptosis upon genotoxic drug treatment. In human primary retinoblastoma, high expression of UHRF1 and XRCC4 could be detected, and elevated XRCC4 expression correlated with reduced apoptosis markers, implying that UHRF1-mediated XRCC4 upregulation under pathophysiological conditions triggered by RB1 gene inactivation may confer protection against endogenous DNA damages that arise during retinoblastoma development. Taken together, these results present a new mechanistic insight into how UHRF1 mediates its tumor-promoting functions in retinoblastoma, and also provide a basis for UHRF1 targeting to improve the efficacy of current chemotherapy for retinoblastoma treatment.
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Vadla R, Haldar D. Mammalian target of rapamycin complex 2 (mTORC2) controls glycolytic gene expression by regulating Histone H3 Lysine 56 acetylation. Cell Cycle 2018; 17:110-123. [PMID: 29143563 DOI: 10.1080/15384101.2017.1404207] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Metabolic reprogramming is a hallmark of cancer cells, but the mechanisms are not well understood. The mammalian target of rapamycin complex 2 (mTORC2) controls cell growth and proliferation and plays a critical role in metabolic reprogramming in glioma. mTORC2 regulates cellular processes such as cell survival, metabolism, and proliferation by phosphorylation of AGC kinases. Components of mTORC2 are shown to localize to the nucleus, but whether mTORC2 modulates epigenetic modifications to regulate gene expression is not known. Here, we identified histone H3 lysine 56 acetylation (H3K56Ac) is regulated by mTORC2 and show that global H3K56Ac levels were downregulated on mTORC2 knockdown but not on mTORC1 knockdown. mTORC2 promotes H3K56Ac in a tuberous sclerosis complex 1/2 (TSC1/2) mediated signaling pathway. We show that knockdown of sirtuin6 (SIRT6) prevented H3K56 deacetylation in mTORC2 depleted cells. Using glioma model consisting of U87EGFRvIII cells, we established that mTORC2 promotes H3K56Ac in glioma. Finally, we show that mTORC2 regulates the expression of glycolytic genes by regulating H3K56Ac levels at the promoters of these genes in glioma cells and depletion of mTOR leads to increased recruitment of SIRT6 to these promoters. Collectively, these results identify mTORC2 signaling pathway positively promotes H3K56Ac through which it may mediate metabolic reprogramming in glioma.
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Affiliation(s)
- Raghavendra Vadla
- a Centre for DNA Fingerprinting and Diagnostics , Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039 , Ranga Reddy District , India.,b Graduate Studies , Manipal University , Manipal , India
| | - Devyani Haldar
- a Centre for DNA Fingerprinting and Diagnostics , Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039 , Ranga Reddy District , India
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20
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Kanungo J. DNA-PK and P38 MAPK: A Kinase Collusion in Alzheimer's Disease? BRAIN DISORDERS & THERAPY 2017; 6:232. [PMID: 28706768 PMCID: PMC5504707 DOI: 10.4172/2168-975x.1000232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The pathogenesis of Alzheimer's disease (AD), characterized by prevalent neuronal death and extracellular deposit of amyloid plaques, is poorly understood. DNA lesions downstream of reduced DNA repair ability have been reported in AD brains. Neurons predominantly use a mechanism to repair double-strand DNA breaks (DSB), which is non-homologous end joining (NHEJ). NHEJ requires DNA-dependent protein kinase (DNA-PK) activity. DNA-PK is a holoenzyme comprising the p460 kD catalytic subunit (DNA-PKcs) and its activator Ku, a heterodimer of p86 and p70 subunits. Ku first binds and then recruits DNA-PKcs to double-stranded DNA ends before NHEJ process begins. Studies have shown reduced NHEJ activity as well as DNA-PKcs and Ku protein levels in AD brains suggesting possible contribution of unrepaired DSB to AD development. However, normal aging brains also show reduced DNA-PKcs and Ku levels thus challenging the notion of any direct link between NHEJ and AD. Another kinase, p38 MAPK is induced by various DNA damaging agents and DSB itself. Increased DNA damage with aging could induce p38 MAPK and its induction may be sustained when DNA repair is compromised in the brain with reduced DNA-PK activity. Combined, these two events may potentially set the stage for an awry nervous system approaching AD.
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Affiliation(s)
- Jyotshna Kanungo
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, USA
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21
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Cell resistance to the Cytolethal Distending Toxin involves an association of DNA repair mechanisms. Sci Rep 2016; 6:36022. [PMID: 27775089 PMCID: PMC5075911 DOI: 10.1038/srep36022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/10/2016] [Indexed: 02/06/2023] Open
Abstract
The Cytolethal Distending Toxin (CDT), produced by many bacteria, has been associated with various diseases including cancer. CDT induces DNA double-strand breaks (DSBs), leading to cell death or mutagenesis if misrepaired. At low doses of CDT, other DNA lesions precede replication-dependent DSB formation, implying that non-DSB repair mechanisms may contribute to CDT cell resistance. To address this question, we developed a proliferation assay using human cell lines specifically depleted in each of the main DNA repair pathways. Here, we validate the involvement of the two major DSB repair mechanisms, Homologous Recombination and Non Homologous End Joining, in the management of CDT-induced lesions. We show that impairment of single-strand break repair (SSBR), but not nucleotide excision repair, sensitizes cells to CDT, and we explore the interplay of SSBR with the DSB repair mechanisms. Finally, we document the role of the replicative stress response and demonstrate the involvement of the Fanconi Anemia repair pathway in response to CDT. In conclusion, our work indicates that cellular survival to CDT-induced DNA damage involves different repair pathways, in particular SSBR. This reinforces a model where CDT-related genotoxicity primarily involves SSBs rather than DSBs, underlining the importance of cell proliferation during CDT intoxication and pathogenicity.
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Sharma MK, Imamichi S, Fukuchi M, Samarth RM, Tomita M, Matsumoto Y. In cellulo phosphorylation of XRCC4 Ser320 by DNA-PK induced by DNA damage. JOURNAL OF RADIATION RESEARCH 2016; 57:115-20. [PMID: 26666690 PMCID: PMC4795952 DOI: 10.1093/jrr/rrv086] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/14/2015] [Accepted: 10/25/2015] [Indexed: 05/24/2023]
Abstract
XRCC4 is a protein associated with DNA Ligase IV, which is thought to join two DNA ends at the final step of DNA double-strand break repair through non-homologous end joining. In response to treatment with ionizing radiation or DNA damaging agents, XRCC4 undergoes DNA-PK-dependent phosphorylation. Furthermore, Ser260 and Ser320 (or Ser318 in alternatively spliced form) of XRCC4 were identified as the major phosphorylation sites by purified DNA-PK in vitro through mass spectrometry. However, it has not been clear whether these sites are phosphorylated in vivo in response to DNA damage. In the present study, we generated an antibody that reacts with XRCC4 phosphorylated at Ser320 and examined in cellulo phosphorylation status of XRCC4 Ser320. The phosphorylation of XRCC4 Ser320 was induced by γ-ray irradiation and treatment with Zeocin. The phosphorylation of XRCC4 Ser320 was detected even after 1 Gy irradiation and increased in a manner dependent on radiation dose. The phosphorylation was observed immediately after irradiation and remained mostly unchanged for up to 4 h. The phosphorylation was inhibited by DNA-PK inhibitor NU7441 and was undetectable in DNA-PKcs-deficient cells, indicating that the phosphorylation was mainly mediated by DNA-PK. These results suggested potential usefulness of the phosphorylation status of XRCC4 Ser320 as an indicator of DNA-PK functionality in living cells.
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Affiliation(s)
- Mukesh Kumar Sharma
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-30 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan Department of Zoology, R.R. Government College, Alwar 301001, India
| | - Shoji Imamichi
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-30 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan Division of Chemotherapy and Clinical Research, National Cancer Center Research Institute, Tokyo 104-0045, Japan
| | - Mikoto Fukuchi
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-30 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Ravindra Mahadeo Samarth
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-30 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan Department of Research, Bhopal Memorial Hospital & Research Centre, Department of Health Research, Raisen Bypass Road, Bhopal 462038, India National Institute for Research in Environmental Health, Indian Council of Medical Research, Kamla Nehru Hospital Building, Gandhi Medical College Campus, Bhopal 462001, India
| | - Masanori Tomita
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, Tokyo 201-8511, Japan
| | - Yoshihisa Matsumoto
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-30 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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Cristini A, Park JH, Capranico G, Legube G, Favre G, Sordet O. DNA-PK triggers histone ubiquitination and signaling in response to DNA double-strand breaks produced during the repair of transcription-blocking topoisomerase I lesions. Nucleic Acids Res 2016; 44:1161-78. [PMID: 26578593 PMCID: PMC4756817 DOI: 10.1093/nar/gkv1196] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 12/12/2022] Open
Abstract
Although defective repair of DNA double-strand breaks (DSBs) leads to neurodegenerative diseases, the processes underlying their production and signaling in non-replicating cells are largely unknown. Stabilized topoisomerase I cleavage complexes (Top1cc) by natural compounds or common DNA alterations are transcription-blocking lesions whose repair depends primarily on Top1 proteolysis and excision by tyrosyl-DNA phosphodiesterase-1 (TDP1). We previously reported that stabilized Top1cc produce transcription-dependent DSBs that activate ATM in neurons. Here, we use camptothecin (CPT)-treated serum-starved quiescent cells to induce transcription-blocking Top1cc and show that those DSBs are generated during Top1cc repair from Top1 peptide-linked DNA single-strand breaks generated after Top1 proteolysis and before excision by TDP1. Following DSB induction, ATM activates DNA-PK whose inhibition suppresses H2AX and H2A ubiquitination and the later assembly of activated ATM into nuclear foci. Inhibition of DNA-PK also reduces Top1 ubiquitination and proteolysis as well as resumption of RNA synthesis suggesting that DSB signaling further enhances Top1cc repair. Finally, we show that co-transcriptional DSBs kill quiescent cells. Together, these new findings reveal that DSB production and signaling by transcription-blocking Top1 lesions impact on non-replicating cell fate and provide insights on the molecular pathogenesis of neurodegenerative diseases such as SCAN1 and AT syndromes, which are caused by TDP1 and ATM deficiency, respectively.
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Affiliation(s)
- Agnese Cristini
- Cancer Research Center of Toulouse, INSERM UMR1037, Toulouse 31037, France
| | - Joon-Hyung Park
- Cancer Research Center of Toulouse, INSERM UMR1037, Toulouse 31037, France
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Gaëlle Legube
- Université de Toulouse, UPS, LBCMCP, 31062 Toulouse, France CNRS, LBCMCP, 31062 Toulouse, France
| | - Gilles Favre
- Cancer Research Center of Toulouse, INSERM UMR1037, Toulouse 31037, France
| | - Olivier Sordet
- Cancer Research Center of Toulouse, INSERM UMR1037, Toulouse 31037, France
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Ghosh S, Liu B, Wang Y, Hao Q, Zhou Z. Lamin A Is an Endogenous SIRT6 Activator and Promotes SIRT6-Mediated DNA Repair. Cell Rep 2015; 13:1396-1406. [PMID: 26549451 DOI: 10.1016/j.celrep.2015.10.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/13/2015] [Accepted: 10/02/2015] [Indexed: 01/08/2023] Open
Abstract
The nuclear lamins are essential for various molecular events in the nucleus, such as chromatin organization, DNA replication, and provision of mechanical support. A specific point mutation in the LMNA gene creates a truncated prelamin A termed progerin, causing Hutchinson-Gilford progeria syndrome (HGPS). SIRT6 deficiency leads to defective genomic maintenance and accelerated aging similar to HGPS, suggesting a potential link between lamin A and SIRT6. Here, we report that lamin A is an endogenous activator of SIRT6 and facilitates chromatin localization of SIRT6 upon DNA damage. Lamin A promotes SIRT6-dependent DNA-PKcs (DNA-PK catalytic subunit) recruitment to chromatin, CtIP deacetylation, and PARP1 mono-ADP ribosylation in response to DNA damage. The presence of progerin jeopardizes SIRT6 activation and compromises SIRT6-mediated molecular events in response to DNA damage. These data reveal a critical role for lamin A in regulating SIRT6 activities, suggesting that defects in SIRT6 functions contribute to impaired DNA repair and accelerated aging in HGPS.
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Affiliation(s)
- Shrestha Ghosh
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pok Fu Lam, Hong Kong; Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen 518000, China
| | - Baohua Liu
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pok Fu Lam, Hong Kong; School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Yi Wang
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pok Fu Lam, Hong Kong
| | - Quan Hao
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pok Fu Lam, Hong Kong
| | - Zhongjun Zhou
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pok Fu Lam, Hong Kong; Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen 518000, China.
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25
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Nguyen PK, Lee WH, Li YF, Hong WX, Hu S, Chan C, Liang G, Nguyen I, Ong SG, Churko J, Wang J, Altman RB, Fleischmann D, Wu JC. Assessment of the Radiation Effects of Cardiac CT Angiography Using Protein and Genetic Biomarkers. JACC Cardiovasc Imaging 2015. [PMID: 26210695 DOI: 10.1016/j.jcmg.2015.04.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The purpose of this study was to evaluate whether radiation exposure from cardiac computed tomographic angiography (CTA) is associated with deoxyribonucleic acid (DNA) damage and whether damage leads to programmed cell death and activation of genes involved in apoptosis and DNA repair. BACKGROUND Exposure to radiation from medical imaging has become a public health concern, but whether it causes significant cell damage remains unclear. METHODS We conducted a prospective cohort study in 67 patients undergoing cardiac CTA between January 2012 and December 2013 in 2 U.S. medical centers. Median blood radiation exposure was estimated using phantom dosimetry. Biomarkers of DNA damage and apoptosis were measured by flow cytometry, whole genome sequencing, and single cell polymerase chain reaction. RESULTS The median dose length product was 1,535.3 mGy·cm (969.7 to 2,674.0 mGy·cm). The median radiation dose to the blood was 29.8 mSv (18.8 to 48.8 mSv). Median DNA damage increased 3.39% (1.29% to 8.04%, p < 0.0001) and median apoptosis increased 3.1-fold (interquartile range [IQR]: 1.4- to 5.1-fold, p < 0.0001) post-radiation. Whole genome sequencing revealed changes in the expression of 39 transcription factors involved in the regulation of apoptosis, cell cycle, and DNA repair. Genes involved in mediating apoptosis and DNA repair were significantly changed post-radiation, including DDB2 (1.9-fold [IQR: 1.5- to 3.0-fold], p < 0.001), XRCC4 (3.0-fold [IQR: 1.1- to 5.4-fold], p = 0.005), and BAX (1.6-fold [IQR: 0.9- to 2.6-fold], p < 0.001). Exposure to radiation was associated with DNA damage (odds ratio [OR]: 1.8 [1.2 to 2.6], p = 0.003). DNA damage was associated with apoptosis (OR: 1.9 [1.2 to 5.1], p < 0.0001) and gene activation (OR: 2.8 [1.2 to 6.2], p = 0.002). CONCLUSIONS Patients exposed to >7.5 mSv of radiation from cardiac CTA had evidence of DNA damage, which was associated with programmed cell death and activation of genes involved in apoptosis and DNA repair.
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Affiliation(s)
- Patricia K Nguyen
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Veterans Administration Palo Alto, Palo Alto, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California.
| | - Won Hee Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Yong Fuga Li
- Department of Genetics, Stanford University School of Medicine, Stanford, California
| | - Wan Xing Hong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Shijun Hu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Charles Chan
- Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Grace Liang
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Ivy Nguyen
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Sang-Ging Ong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Jared Churko
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Jia Wang
- Environmental Health and Safety, Stanford University School of Medicine, Stanford, California
| | - Russ B Altman
- Department of Genetics, Stanford University School of Medicine, Stanford, California
| | - Dominik Fleischmann
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Radiology, Stanford University School of Medicine, Stanford, California
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California; Department of Radiology, Stanford University School of Medicine, Stanford, California.
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26
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Li W, Gu X, Zhang X, Kong J, Ding N, Qi Y, Zhang Y, Wang J, Huang D. Cadmium delays non-homologous end joining (NHEJ) repair via inhibition of DNA-PKcs phosphorylation and downregulation of XRCC4 and Ligase IV. Mutat Res 2015. [PMID: 26201248 DOI: 10.1016/j.mrfmmm.2015.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although studies have shown that cadmium (Cd) interfered with DNA damage repair (DDR), whether Cd could affect non-homologous end joining (NHEJ) repair remains elusive. To further understand the effect of Cd on DDR, we used X-ray irradiation of Hela cells as an in vitro model system, along with γH2AX and 53BP1 as markers for DNA damage. Results showed that X-ray significantly increased γH2AX and 53BP1 foci in Hela cells (p < 0.01), all of which are characteristic of accrued DNA damage. The number of foci declined rapidly over time (1-8h postirradiation), indicating an initiation of NHEJ process. However, the disappearance of γH2AX and 53BP1 foci was remarkably slowed by Cd pretreatment (p < 0.01), suggesting that Cd reduced the efficiency of NHEJ. To further elucidate the mechanisms of Cd toxicity, several markers of NHEJ pathway including Ku70, DNA-PKcs, XRCC4 and Ligase IV were examined. Our data showed that Cd altered the phosphorylation of DNA-PKcs, and reduced the expression of both XRCC4 and Ligase IV in irradiated cells. These observations are indicative of the impairment of NHEJ-dependent DNA repair pathways. In addition, zinc (Zn) mitigated the effects of Cd on NHEJ, suggesting that the Cd-induced NHEJ alteration may partly result from the displacement of Zn or from an interference with the normal function of Zn-containing proteins by Cd. Our findings provide a new insight into the toxicity of Cd on NHEJ repair and its underlying mechanisms in human cells.
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Affiliation(s)
- Weiwei Li
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xueyan Gu
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaoning Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jinxin Kong
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Nan Ding
- Gansu Key laboratory of Space Radiobiology, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yongmei Qi
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yingmei Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jufang Wang
- Gansu Key laboratory of Space Radiobiology, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Dejun Huang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
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Keka IS, Mohiuddin, Maede Y, Rahman MM, Sakuma T, Honma M, Yamamoto T, Takeda S, Sasanuma H. Smarcal1 promotes double-strand-break repair by nonhomologous end-joining. Nucleic Acids Res 2015; 43:6359-72. [PMID: 26089390 PMCID: PMC4513880 DOI: 10.1093/nar/gkv621] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/03/2015] [Indexed: 12/02/2022] Open
Abstract
Smarcal1 is a SWI/SNF-family protein with an ATPase domain involved in DNA-annealing activities and a binding site for the RPA single-strand-DNA-binding protein. Although the role played by Smarcal1 in the maintenance of replication forks has been established, it remains unknown whether Smarcal1 contributes to genomic DNA maintenance outside of the S phase. We disrupted the SMARCAL1 gene in both the chicken DT40 and the human TK6 B cell lines. The resulting SMARCAL1−/− clones exhibited sensitivity to chemotherapeutic topoisomerase 2 inhibitors, just as nonhomologous end-joining (NHEJ) null-deficient cells do. SMARCAL1−/− cells also exhibited an increase in radiosensitivity in the G1 phase. Moreover, the loss of Smarcal1 in NHEJ null-deficient cells does not further increase their radiosensitivity. These results demonstrate that Smarcal1 is required for efficient NHEJ-mediated DSB repair. Both inactivation of the ATPase domain and deletion of the RPA-binding site cause the same phenotype as does null-mutation of Smarcal1, suggesting that Smarcal1 enhances NHEJ, presumably by interacting with RPA at unwound single-strand sequences and then facilitating annealing at DSB ends. SMARCAL1−/−cells showed a poor accumulation of Ku70/DNA-PKcs and XRCC4 at DNA-damage sites. We propose that Smarcal1 maintains the duplex status of DSBs to ensure proper recruitment of NHEJ factors to DSB sites.
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Affiliation(s)
- Islam Shamima Keka
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mohiuddin
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuko Maede
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Md Maminur Rahman
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Kyoto University, Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
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28
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Chatterjee P, Choudhary GS, Alswillah T, Xiong X, Heston WD, Magi-Galluzzi C, Zhang J, Klein EA, Almasan A. The TMPRSS2-ERG Gene Fusion Blocks XRCC4-Mediated Nonhomologous End-Joining Repair and Radiosensitizes Prostate Cancer Cells to PARP Inhibition. Mol Cancer Ther 2015; 14:1896-906. [PMID: 26026052 DOI: 10.1158/1535-7163.mct-14-0865] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 05/19/2015] [Indexed: 11/16/2022]
Abstract
Exposure to genotoxic agents, such as ionizing radiation (IR), produces DNA damage, leading to DNA double-strand breaks (DSB); IR toxicity is augmented when the DNA repair is impaired. We reported that radiosensitization by a PARP inhibitor (PARPi) was highly prominent in prostate cancer cells expressing the TMPRSS2-ERG gene fusion protein. Here, we show that TMPRSS2-ERG blocks nonhomologous end-joining (NHEJ) DNA repair by inhibiting DNA-PKcs. VCaP cells, which harbor TMPRSS2-ERG and PC3 cells that stably express it, displayed γH2AX and 53BP1 foci constitutively, indicating persistent DNA damage that was absent if TMPRSS2-ERG was depleted by siRNA in VCaP cells. The extent of DNA damage was enhanced and associated with TMPRSS2-ERG's ability to inhibit DNA-PKcs function, as indicated by its own phosphorylation (Thr2609, Ser2056) and that of its substrate, Ser1778-53BP1. DNA-PKcs deficiency caused by TMPRSS2-ERG destabilized critical NHEJ components on chromatin. Thus, XRCC4 was not recruited to chromatin, with retention of other NHEJ core factors being reduced. DNA-PKcs autophosphorylation was restored to the level of parental cells when TMPRSS2-ERG was depleted by siRNA. Following IR, TMPRSS2-ERG-expressing PC3 cells had elevated Rad51 foci and homologous recombination (HR) activity, indicating that HR compensated for defective NHEJ in these cells, hence addressing why TMPRSS2-ERG alone did not lead to radiosensitization. However, the presence of TMPRSS2-ERG, by inhibiting NHEJ DNA repair, enhanced PARPi-mediated radiosensitization. IR in combination with PARPi resulted in enhanced DNA damage in TMPRSS2-ERG-expressing cells. Therefore, by inhibiting NHEJ, TMPRSS2-ERG provides a synthetic lethal interaction with PARPi in prostate cancer patients expressing TMPRSS2-ERG.
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Affiliation(s)
- Payel Chatterjee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio. School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Gaurav S Choudhary
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio. Department of Pathology, Case Western Reserve University School of Medicine, Ohio
| | | | - Xiahui Xiong
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Warren D Heston
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Cristina Magi-Galluzzi
- Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio. Robert J. Tomisch Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio
| | - Junran Zhang
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Eric A Klein
- Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio
| | - Alexandru Almasan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio. Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
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Fukuchi M, Wanotayan R, Liu S, Imamichi S, Sharma MK, Matsumoto Y. Lysine 271 but not lysine 210 of XRCC4 is required for the nuclear localization of XRCC4 and DNA ligase IV. Biochem Biophys Res Commun 2015; 461:687-94. [PMID: 25934149 DOI: 10.1016/j.bbrc.2015.04.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/18/2015] [Indexed: 11/16/2022]
Abstract
XRCC4 and DNA Ligase IV (LIG4) cooperate to join two DNA ends at the final step of DNA double-strand break (DSB) repair through non-homologous end-joining (NHEJ). However, it is not fully understood how these proteins are localized to the nucleus. Here we created XRCC4(K271R) mutant, as Lys271 lies within the putative nuclear localization signal (NLS), and XRCC4(K210R) mutant, as Lys210 was reported to undergo SUMOylation, implicated in the nuclear localization of XRCC4. Wild-type and mutated XRCC4 with EGFP tag were introduced into HeLa cell, in which endogenous XRCC4 had been knocked down using siRNA directed to 3'-untranslated region, and tested for the nuclear localization function by fluorescence microscopy. XRCC4(K271R) was defective in the nuclear localization of itself and LIG4, whereas XRCC4(K210R) was competent for the nuclear localization with LIG4. To examine DSB repair function, wild-type and mutated XRCC4 were introduced into XRCC4-deficient M10. M10-XRCC4(K271R), but not M10-XRCC4(K210R), showed significantly reduced surviving fraction after 2 Gy γ-ray irradiation as compared to M10-XRCC4(WT). The number of γ-H2AX foci remaining 2 h after 2 Gy γ-ray irradiation was significantly greater in M10-XRCC4(K271R) than in M10-XRCC4(WT), whereas it was only marginally increased in M10-XRCC4(K210R) as compared to M10-XRCC4(WT). The present results collectively indicated that Lys271, but not Lys210, of XRCC4 is required for the nuclear localization of XRCC4 and LIG4 and that the nuclear localizing ability is essential for DSB repair function of XRCC4.
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Affiliation(s)
- Mikoto Fukuchi
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Rujira Wanotayan
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Sicheng Liu
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Shoji Imamichi
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Mukesh Kumar Sharma
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Yoshihisa Matsumoto
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
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Wanotayan R, Fukuchi M, Imamichi S, Sharma MK, Matsumoto Y. Asparagine 326 in the extremely C-terminal region of XRCC4 is essential for the cell survival after irradiation. Biochem Biophys Res Commun 2015; 457:526-31. [PMID: 25597996 DOI: 10.1016/j.bbrc.2015.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 01/07/2015] [Indexed: 12/25/2022]
Abstract
XRCC4 is one of the crucial proteins in the repair of DNA double-strand break (DSB) through non-homologous end-joining (NHEJ). As XRCC4 consists of 336 amino acids, N-terminal 200 amino acids include domains for dimerization and for association with DNA ligase IV and XLF and shown to be essential for XRCC4 function in DSB repair and V(D)J recombination. On the other hand, the role of the remaining C-terminal region of XRCC4 is not well understood. In the present study, we noticed that a stretch of ∼20 amino acids located at the extreme C-terminus of XRCC4 is highly conserved among vertebrate species. To explore its possible importance, series of mutants in this region were constructed and assessed for the functionality in terms of ability to rescue radiosensitivity of M10 cells lacking XRCC4. Among 13 mutants, M10 transfectant with N326L mutant (M10-XRCC4(N326L)) showed elevated radiosensitivity. N326L protein showed defective nuclear localization. N326L sequence matched the consensus sequence of nuclear export signal. Leptomycin B treatment accumulated XRCC4(N326L) in the nucleus but only partially rescued radiosensitivity of M10-XRCC4(N326L). These results collectively indicated that the functional defects of XRCC4(N326L) might be partially, but not solely, due to its exclusion from nucleus by synthetic nuclear export signal. Further mutation of XRCC4 Asn326 to other amino acids, i.e., alanine, aspartic acid or glutamine did not affect the nuclear localization but still exhibited radiosensitivity. The present results indicated the importance of the extremely C-terminal region of XRCC4 and, especially, Asn326 therein.
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Affiliation(s)
- Rujira Wanotayan
- Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Mikoto Fukuchi
- Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Shoji Imamichi
- Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Mukesh Kumar Sharma
- Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Yoshihisa Matsumoto
- Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
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Kim MR, Lee J, An YS, Jin YB, Park IC, Chung E, Shin I, Barcellos-Hoff MH, Yi JY. TGFβ1 protects cells from γ-IR by enhancing the activity of the NHEJ repair pathway. Mol Cancer Res 2014; 13:319-29. [PMID: 25319009 DOI: 10.1158/1541-7786.mcr-14-0098-t] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Several groups have reported that TGFβ1 regulates cellular responses to γ-irradiation; however, the exact mechanism has not been fully elucidated. In the current study, the role of TGFβ1 in cellular responses to γ-irradiation was investigated in detail. The data indicate that TGFβ1 pretreatment decreased the aftermath of ionizing radiation (IR)-induced DNA damage in a SMAD-dependent manner. To determine the underlying mechanism for these effects, the extent of IR-induced DNA repair activity in the presence or absence of TGFβ1 was examined. Studies reveal that TGFβ1 upregulated DNA ligase IV (Lig4), augmented IR-induced nuclear retention of the DNA ligase, and enhanced nonhomologous end-joining (NHEJ) repair activity. In addition, knockdown of Lig4 reduced the TGFβ1-induced protection against IR. Overall, these data indicate that TGFβ1 facilitates the NHEJ repair process upon γ-irradiation and thereby enhances long-term survival. IMPLICATIONS These findings provide new insight and a possible approach to controlling genotoxic stress by the TGFβ signaling pathway.
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Affiliation(s)
- Mi-Ra Kim
- Division of Radiation Effects, Korea Institute of Radiation and Medical Sciences, Seoul, Korea
| | - Jeeyong Lee
- Division of Radiation Effects, Korea Institute of Radiation and Medical Sciences, Seoul, Korea
| | - You Sun An
- Division of Radiation Effects, Korea Institute of Radiation and Medical Sciences, Seoul, Korea
| | - Yeung Bae Jin
- Korea Research Institute of Bioscience and Biotechnology, National Primate Research Center, Cheongju-si, Chungbuk, Korea
| | - In-Chul Park
- Division of Radiation Cancer Research, Korea Institute of Radiation and Medical Sciences, Seoul, Korea
| | - Eunkyung Chung
- Department of Genetic Engineering, College of Life Science, Kyung Hee University, Yongin, Gyeonggi-do, Korea
| | - Incheol Shin
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Korea
| | - Mary Helen Barcellos-Hoff
- Department of Radiation Oncology and Cell Biology, New York University of Medicine, New York, New York
| | - Jae Youn Yi
- Division of Radiation Effects, Korea Institute of Radiation and Medical Sciences, Seoul, Korea.
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Chaudhary N, Nakka KK, Chavali PL, Bhat J, Chatterjee S, Chattopadhyay S. SMAR1 coordinates HDAC6-induced deacetylation of Ku70 and dictates cell fate upon irradiation. Cell Death Dis 2014; 5:e1447. [PMID: 25299772 PMCID: PMC4237237 DOI: 10.1038/cddis.2014.397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/11/2014] [Accepted: 08/14/2014] [Indexed: 11/30/2022]
Abstract
Acetylation status of DNA end joining protein Ku70 dictates its function in DNA repair and Bax-mediated apoptosis. Despite the knowledge of HDACs and HATs that are reported to modulate the acetylation dynamics of Ku70, very little is known about proteins that critically coordinate these key modifications. Here, we demonstrate that nuclear matrix-associated protein scaffold/matrix-associated region-binding protein 1 (SMAR1) is a novel interacting partner of Ku70 and coordinates with HDAC6 to maintain Ku70 in a deacetylated state. Our studies revealed that knockdown of SMAR1 results in enhanced acetylation of Ku70, which leads to impaired recruitment of Ku70 in the chromatin fractions. Interestingly, ionizing radiation (IR) induces the expression of SMAR1 and its redistribution as distinct nuclear foci upon ATM-mediated phosphorylation at serine 370. Furthermore, SMAR1 regulates IR-induced G2/M cell cycle arrest by facilitating Chk2 phosphorylation. Alternatively, SMAR1 provides radioresistance by modulating the association of deacetylated Ku70 with Bax, abrogating the mitochondrial translocation of Bax. Thus, we provide mechanistic insights of SMAR1-mediated regulation of repair and apoptosis via a complex crosstalk involving Ku70, HDAC6 and Bax.
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Affiliation(s)
- N Chaudhary
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune University Campus, Pune, India
| | - K K Nakka
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune University Campus, Pune, India
| | - P L Chavali
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune University Campus, Pune, India
| | - J Bhat
- Department of Biophysics, Bose Institute, Kolkata, India
| | - S Chatterjee
- Department of Biophysics, Bose Institute, Kolkata, India
| | - S Chattopadhyay
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune University Campus, Pune, India
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Britton S, Dernoncourt E, Delteil C, Froment C, Schiltz O, Salles B, Frit P, Calsou P. DNA damage triggers SAF-A and RNA biogenesis factors exclusion from chromatin coupled to R-loops removal. Nucleic Acids Res 2014; 42:9047-62. [PMID: 25030905 PMCID: PMC4132723 DOI: 10.1093/nar/gku601] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We previously identified the heterogeneous ribonucleoprotein SAF-A/hnRNP U as a substrate for DNA-PK, a protein kinase involved in DNA damage response (DDR). Using laser micro-irradiation in human cells, we report here that SAF-A exhibits a two-phase dynamics at sites of DNA damage, with a rapid and transient recruitment followed by a prolonged exclusion. SAF-A recruitment corresponds to its binding to Poly(ADP-ribose) while its exclusion is dependent on the activity of ATM, ATR and DNA-PK and reflects the dissociation from chromatin of SAF-A associated with ongoing transcription. Having established that SAF-A RNA-binding domain recapitulates SAF-A dynamics, we show that this domain is part of a complex comprising several mRNA biogenesis proteins of which at least two, FUS/TLS and TAFII68/TAF15, exhibit similar biphasic dynamics at sites of damage. Using an original reporter for live imaging of DNA:RNA hybrids (R-loops), we show a transient transcription-dependent accumulation of R-loops at sites of DNA damage that is prolonged upon inhibition of RNA biogenesis factors exclusion. We propose that a new component of the DDR is an active anti-R-loop mechanism operating at damaged transcribed sites which includes the exclusion of mRNA biogenesis factors such as SAF-A, FUS and TAF15.
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Affiliation(s)
- Sébastien Britton
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France Equipe Labellisée Ligue Nationale Contre le Cancer
| | - Emma Dernoncourt
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France Equipe Labellisée Ligue Nationale Contre le Cancer
| | - Christine Delteil
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France Equipe Labellisée Ligue Nationale Contre le Cancer
| | - Carine Froment
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Odile Schiltz
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Bernard Salles
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Philippe Frit
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France Equipe Labellisée Ligue Nationale Contre le Cancer
| | - Patrick Calsou
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), BP 64182, 205 route de Narbonne, F-31077 Toulouse, Cedex 4, France Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France Equipe Labellisée Ligue Nationale Contre le Cancer
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Abstract
BACKGROUND Many aspects of autoimmune disease are not well understood, including the specificities of autoimmune targets, and patterns of co-morbidity and cross-heritability across diseases. Prior work has provided evidence that somatic mutation caused by gene conversion and deletion at segmentally duplicated loci is relevant to several diseases. Simple tandem repeat (STR) sequence is highly mutable, both somatically and in the germ-line, and somatic STR mutations are observed under inflammation. RESULTS Protein-coding genes spanning STRs having markers of mutability, including germ-line variability, high total length, repeat count and/or repeat similarity, are evaluated in the context of autoimmunity. For the initiation of autoimmune disease, antigens whose autoantibodies are the first observed in a disease, termed primary autoantigens, are informative. Three primary autoantigens, thyroid peroxidase (TPO), phogrin (PTPRN2) and filaggrin (FLG), include STRs that are among the eleven longest STRs spanned by protein-coding genes. This association of primary autoantigens with long STR sequence is highly significant (p<3.0x10(-7)). Long STRs occur within twenty genes that are associated with sixteen common autoimmune diseases and atherosclerosis. The repeat within the TTC34 gene is an outlier in terms of length and a link with systemic lupus erythematosus is proposed. CONCLUSIONS The results support the hypothesis that many autoimmune diseases are triggered by immune responses to proteins whose DNA sequence mutates somatically in a coherent, consistent fashion. Other autoimmune diseases may be caused by coherent somatic mutations in immune cells. The coherent somatic mutation hypothesis has the potential to be a comprehensive explanation for the initiation of many autoimmune diseases.
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Affiliation(s)
- Kenneth Andrew Ross
- Department of Computer Science, Columbia University, New York, New York, United States of America
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35
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Francis DB, Kozlov M, Chavez J, Chu J, Malu S, Hanna M, Cortes P. DNA Ligase IV regulates XRCC4 nuclear localization. DNA Repair (Amst) 2014; 21:36-42. [PMID: 24984242 DOI: 10.1016/j.dnarep.2014.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 05/22/2014] [Accepted: 05/29/2014] [Indexed: 11/17/2022]
Abstract
DNA Ligase IV, along with its interacting partner XRCC4, are essential for repairing DNA double strand breaks by non-homologous end joining (NHEJ). Together, they complete the final ligation step resolving the DNA break. Ligase IV is regulated by XRCC4 and XLF. However, the mechanism(s) by which Ligase IV control the NHEJ reaction and other NHEJ factor(s) remains poorly characterized. Here, we show that a C-terminal region of Ligase IV (aa 620-800), which encompasses a NLS, the BRCT I, and the XRCC4 interacting region (XIR), is essential for nuclear localization of its co-factor XRCC4. In Ligase IV deficient cells, XRCC4 showed deregulated localization remaining in the cytosol even after induction of DNA double strand breaks. DNA Ligase IV was also required for efficient localization of XLF into the nucleus. Additionally, human fibroblasts that harbor hypomorphic mutations within the Ligase IV gene displayed decreased levels of XRCC4 protein, implicating that DNA Ligase IV is also regulating XRCC4 stability. Our results provide evidence for a role of DNA Ligase IV in controlling the cellular localization and protein levels of XRCC4.
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Affiliation(s)
- Dailia B Francis
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Mikhail Kozlov
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Jose Chavez
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Jennifer Chu
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Shruti Malu
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Mary Hanna
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Patricia Cortes
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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36
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Grundy GJ, Moulding HA, Caldecott KW, Rulten SL. One ring to bring them all--the role of Ku in mammalian non-homologous end joining. DNA Repair (Amst) 2014; 17:30-8. [PMID: 24680220 DOI: 10.1016/j.dnarep.2014.02.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 02/25/2014] [Indexed: 12/26/2022]
Abstract
The repair of DNA double strand breaks is essential for cell survival and several conserved pathways have evolved to ensure their rapid and efficient repair. The non-homologous end joining pathway is initiated when Ku binds to the DNA break site. Ku is an abundant nuclear heterodimer of Ku70 and Ku80 with a toroidal structure that allows the protein to slide over the broken DNA end and bind with high affinity. Once locked into placed, Ku acts as a tool-belt to recruit multiple interacting proteins, forming one or more non-homologous end joining complexes that act in a regulated manner to ensure efficient repair of DNA ends. Here we review the structure and functions of Ku and the proteins with which it interacts during non-homologous end joining.
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Affiliation(s)
- Gabrielle J Grundy
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
| | - Hayley A Moulding
- School of Biochemistry, Medical Sciences, University Walk, Bristol BS8 1TD, UK
| | - Keith W Caldecott
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
| | - Stuart L Rulten
- Genome Damage and Stability Centre, Science Park Road, Falmer, Brighton BN1 9RQ, UK.
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37
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Woodbine L, Gennery AR, Jeggo PA. Reprint of "The clinical impact of deficiency in DNA non-homologous end-joining". DNA Repair (Amst) 2014; 17:9-20. [PMID: 24780557 DOI: 10.1016/j.dnarep.2014.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 01/10/2023]
Abstract
DNA non-homologous end-joining (NHEJ) is the major DNA double strand break (DSB) repair pathway in mammalian cells. Defects in NHEJ proteins confer marked radiosensitivity in cell lines and mice models, since radiation potently induces DSBs. The process of V(D)J recombination functions during the development of the immune response, and involves the introduction and rejoining of programmed DSBs to generate an array of diverse T and B cells. NHEJ rejoins these programmed DSBs. Consequently, NHEJ deficiency confers (severe) combined immunodeficiency - (S)CID - due to a failure to carry out V(D)J recombination efficiently. NHEJ also functions in class switch recombination, another step enhancing T and B cell diversity. Prompted by these findings, a search for radiosensitivity amongst (S)CID patients revealed a radiosensitive sub-class, defined as RS-SCID. Mutations in NHEJ genes, defining human syndromes deficient in DNA ligase IV (LIG4 Syndrome), XLF-Cernunnos, Artemis or DNA-PKcs, have been identified in such patients. Mutations in XRCC4 or Ku70,80 in patients have not been identified. RS-SCID patients frequently display additional characteristics including microcephaly, dysmorphic facial features and growth delay. Here, we overview the clinical spectrum of RS-SCID patients and discuss our current understanding of the underlying biology.
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Affiliation(s)
- Lisa Woodbine
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Andrew R Gennery
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Penny A Jeggo
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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38
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Unraveling the complexities of DNA-dependent protein kinase autophosphorylation. Mol Cell Biol 2014; 34:2162-75. [PMID: 24687855 DOI: 10.1128/mcb.01554-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) orchestrates DNA repair by regulating access to breaks through autophosphorylations within two clusters of sites (ABCDE and PQR). Blocking ABCDE phosphorylation (by alanine mutation) imparts a dominant negative effect, rendering cells hypersensitive to agents that cause DNA double-strand breaks. Here, a mutational approach is used to address the mechanistic basis of this dominant negative effect. Blocking ABCDE phosphorylation hypersensitizes cells to most types of DNA damage (base damage, cross-links, breaks, and damage induced by replication stress), suggesting that DNA-PK binds DNA ends that result from many DNA lesions and that blocking ABCDE phosphorylation sequesters these DNA ends from other repair pathways. This dominant negative effect requires DNA-PK's catalytic activity, as well as phosphorylation of multiple (non-ABCDE) DNA-PK catalytic subunit (DNA-PKcs) sites. PSIPRED analysis indicates that the ABCDE sites are located in the only contiguous extended region of this huge protein that is predicted to be disordered, suggesting a regulatory role(s) and perhaps explaining the large impact ABCDE phosphorylation has on the enzyme's function. Moreover, additional sites in this disordered region contribute to the ABCDE cluster. These data, coupled with recent structural data, suggest a model whereby early phosphorylations promote initiation of nonhomologous end joining (NHEJ), whereas ABCDE phosphorylations, potentially located in a "hinge" region between the two domains, lead to regulated conformational changes that initially promote NHEJ and eventually disengage NHEJ.
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39
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Woodbine L, Gennery AR, Jeggo PA. The clinical impact of deficiency in DNA non-homologous end-joining. DNA Repair (Amst) 2014; 16:84-96. [PMID: 24629483 DOI: 10.1016/j.dnarep.2014.02.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 12/22/2022]
Abstract
DNA non-homologous end-joining (NHEJ) is the major DNA double strand break (DSB) repair pathway in mammalian cells. Defects in NHEJ proteins confer marked radiosensitivity in cell lines and mice models, since radiation potently induces DSBs. The process of V(D)J recombination functions during the development of the immune response, and involves the introduction and rejoining of programmed DSBs to generate an array of diverse T and B cells. NHEJ rejoins these programmed DSBs. Consequently, NHEJ deficiency confers (severe) combined immunodeficiency - (S)CID - due to a failure to carry out V(D)J recombination efficiently. NHEJ also functions in class switch recombination, another step enhancing T and B cell diversity. Prompted by these findings, a search for radiosensitivity amongst (S)CID patients revealed a radiosensitive sub-class, defined as RS-SCID. Mutations in NHEJ genes, defining human syndromes deficient in DNA ligase IV (LIG4 Syndrome), XLF-Cernunnos, Artemis or DNA-PKcs, have been identified in such patients. Mutations in XRCC4 or Ku70,80 in patients have not been identified. RS-SCID patients frequently display additional characteristics including microcephaly, dysmorphic facial features and growth delay. Here, we overview the clinical spectrum of RS-SCID patients and discuss our current understanding of the underlying biology.
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Affiliation(s)
- Lisa Woodbine
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Andrew R Gennery
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Penny A Jeggo
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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40
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Chatterjee P, Plesca D, Mazumder S, Boutros J, Yannone SM, Almasan A. Defective chromatin recruitment and retention of NHEJ core components in human tumor cells expressing a Cyclin E fragment. Nucleic Acids Res 2013; 41:10157-69. [PMID: 24021630 PMCID: PMC3905870 DOI: 10.1093/nar/gkt812] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Exposure to genotoxic agents, such as ionizing radiation (IR), produces double-strand breaks, repaired predominantly in mammalian cells by non-homologous end-joining (NHEJ). Ku70 was identified as an interacting partner of a proteolytic Cyclin E (CycE) fragment, p18CycE. p18CycE endogenous generation during IR-induced apoptosis in leukemic cells and its stable expression in epithelial tumor cells sensitized to IR. γH2AX IR-induced foci (IRIFs) and comet assays indicated ineffective NHEJ DNA repair in p18CycE-expressing cells. DNA pull-down and chromatin recruitment assays revealed that retention of NHEJ factors to double-strand breaks, but not recruitment, was diminished. Similarly, IRIFs of phosphorylated T2609 and S2056-DNA-PKcs and its target S1778-53BP1 were greatly decreased in p18CycE-expressing cells. As a result, DNA-PKcs chromatin association was also increased. 53BP1 IRIFs were suppressed when p18CycE was generated in leukemic cells and in epithelial cells stably expressing p18CycE. Ataxia telangiectasia mutated was activated but not its 53BP1 and MDC1 targets. These data indicate a profound influence of p18CycE on NHEJ through its interference with DNA-PKcs conformation and/or dimerization, which is required for effective DNA repair, making the p18CycE-expressing cells more IR sensitive. These studies provide unique mechanistic insights into NHEJ misregulation in human tumor cells, in which defects in NHEJ core components are rare.
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Affiliation(s)
- Payel Chatterjee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA, School of Biomedical Sciences, Kent State University, Kent, OH 44234, USA, Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA and Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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C-terminal region of DNA ligase IV drives XRCC4/DNA ligase IV complex to chromatin. Biochem Biophys Res Commun 2013; 439:173-8. [DOI: 10.1016/j.bbrc.2013.08.068] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 08/20/2013] [Indexed: 01/25/2023]
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Goodarzi AA, Jeggo PA. The repair and signaling responses to DNA double-strand breaks. ADVANCES IN GENETICS 2013; 82:1-45. [PMID: 23721719 DOI: 10.1016/b978-0-12-407676-1.00001-9] [Citation(s) in RCA: 165] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A DNA double-strand break (DSB) has long been recognized as a severe cellular lesion, potentially representing an initiating event for carcinogenesis or cell death. The evolution of DSB repair pathways as well as additional processes, such as cell cycle checkpoint arrest, to minimize the cellular impact of DSB formation was, therefore, not surprising. However, the depth and complexity of the DNA damage responses being revealed by current studies were unexpected. Perhaps the most surprising finding to emerge is the dramatic changes to chromatin architecture that arise in the DSB vicinity. In this review, we overview the cellular response to DSBs focusing on DNA repair pathways and the interface between them. We consider additional events which impact upon these DSB repair pathways, including regulated arrest of cell cycle progression and chromatin architecture alterations. Finally, we discuss the impact of defects in these processes to human disease.
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Affiliation(s)
- Aaron A Goodarzi
- Department of Biochemistry & Molecular Biology, Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada
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Britton S, Coates J, Jackson SP. A new method for high-resolution imaging of Ku foci to decipher mechanisms of DNA double-strand break repair. ACTA ACUST UNITED AC 2013; 202:579-95. [PMID: 23897892 PMCID: PMC3734090 DOI: 10.1083/jcb.201303073] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A combination of RNase- and detergent-based preextraction with high-resolution microscopy allows the detection of Ku and other DNA repair proteins at single double-strand breaks in cells. DNA double-strand breaks (DSBs) are the most toxic of all genomic insults, and pathways dealing with their signaling and repair are crucial to prevent cancer and for immune system development. Despite intense investigations, our knowledge of these pathways has been technically limited by our inability to detect the main repair factors at DSBs in cells. In this paper, we present an original method that involves a combination of ribonuclease- and detergent-based preextraction with high-resolution microscopy. This method allows direct visualization of previously hidden repair complexes, including the main DSB sensor Ku, at virtually any type of DSB, including those induced by anticancer agents. We demonstrate its broad range of applications by coupling it to laser microirradiation, super-resolution microscopy, and single-molecule counting to investigate the spatial organization and composition of repair factories. Furthermore, we use our method to monitor DNA repair and identify mechanisms of repair pathway choice, and we show its utility in defining cellular sensitivities and resistance mechanisms to anticancer agents.
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Affiliation(s)
- Sébastien Britton
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN, England, UK
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Vignard J, Mirey G, Salles B. Ionizing-radiation induced DNA double-strand breaks: a direct and indirect lighting up. Radiother Oncol 2013; 108:362-9. [PMID: 23849169 DOI: 10.1016/j.radonc.2013.06.013] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
The occurrence of DNA double-strand breaks (DSBs) induced by ionizing radiation has been extensively studied by biochemical or cell imaging techniques. Cell imaging development relies on technical advances as well as our knowledge of the cell DNA damage response (DDR) process. The DDR involves a complex network of proteins that initiate and coordinate DNA damage signaling and repair activities. As some DDR proteins assemble at DSBs in an established spatio-temporal pattern, visible nuclear foci are produced. In addition, post-translational modifications are important for the signaling and the recruitment of specific partners at damaged chromatin foci. We briefly review here the most widely used methods to study DSBs. We also discuss the development of indirect methods, using reporter expression or intra-nuclear antibodies, to follow the production of DSBs in real time and in living cells.
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Affiliation(s)
- Julien Vignard
- INRA, UMR1331, Université de Toulouse, TOXALIM (Research Centre in Food Toxicology), F-31027 Toulouse, France
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Fischer U, Rheinheimer S, Krempler A, Löbrich M, Meese E. Glioma-amplified sequence KUB3 influences double-strand break repair after ionizing radiation. Int J Oncol 2013; 43:50-6. [PMID: 23670597 PMCID: PMC3742159 DOI: 10.3892/ijo.2013.1937] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 04/05/2013] [Indexed: 01/06/2023] Open
Abstract
Human glioblastomas are characterized by frequent DNA amplifications most often at chromosome regions 7p11.2 and 12q13-15. Although amplification is a well-known hallmark of glioblastoma genetics the function of most amplified genes in glioblastoma biology is not understood. Previously, we cloned Ku70-binding protein 3 (KUB3) from the amplified domain at 12q13-15. Here, we report that glioblastoma cell cultures with endogenous KUB3 gene amplification and with elevated KUB3 protein expression show an efficient double-strand break (DSB) repair after being irradiated with 1 Gy. A significantly less efficient DSB repair was found in glioma cell cultures without KUB3 amplification and expression. Furthermore, we found that a siRNA-mediated reduction of the endogenous KUB3 expression in glioblastoma cells resulted in a reduction of the repair efficiency. HeLa cells transfected with KUB3 showed an increased DSB repair in comparison to untreated HeLa cells. In addition, KUB3 seems to influence DSB efficiency via the DNA-PK-dependent repair pathway as shown by simultaneous inhibition of KUB3 and DNA-PK. The data provide the first evidence for a link between the level of KUB3 amplification and expression in glioma and DSB repair efficiency.
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Affiliation(s)
- Ulrike Fischer
- Department of Human Genetics, Medical School, Saarland University, D-66421 Homburg/Saar, Germany.
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Parvathaneni S, Stortchevoi A, Sommers JA, Brosh RM, Sharma S. Human RECQ1 interacts with Ku70/80 and modulates DNA end-joining of double-strand breaks. PLoS One 2013; 8:e62481. [PMID: 23650516 PMCID: PMC3641083 DOI: 10.1371/journal.pone.0062481] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/21/2013] [Indexed: 01/27/2023] Open
Abstract
Genomic instability is a known precursor to cancer and aging. The RecQ helicases are a highly conserved family of DNA-unwinding enzymes that play key roles in maintaining genome stability in all living organisms. Human RecQ homologs include RECQ1, BLM, WRN, RECQ4, and RECQ5β, three of which have been linked to diseases with elevated risk of cancer and growth defects (Bloom Syndrome and Rothmund-Thomson Syndrome) or premature aging (Werner Syndrome). RECQ1, the first RecQ helicase discovered and the most abundant in human cells, is the least well understood of the five human RecQ homologs. We have previously described that knockout of RECQ1 in mice or knockdown of its expression in human cells results in elevated frequency of spontaneous sister chromatid exchanges, chromosomal instability, increased load of DNA damage and heightened sensitivity to ionizing radiation. We have now obtained evidence implicating RECQ1 in the nonhomologous end-joining pathway of DNA double-strand break repair. We show that RECQ1 interacts directly with the Ku70/80 subunit of the DNA-PK complex, and depletion of RECQ1 results in reduced end-joining in cell free extracts. In vitro, RECQ1 binds and unwinds the Ku70/80-bound partial duplex DNA substrate efficiently. Linear DNA is co-bound by RECQ1 and Ku70/80, and DNA binding by Ku70/80 is modulated by RECQ1. Collectively, these results provide the first evidence for an interaction of RECQ1 with Ku70/80 and a role of the human RecQ helicase in double-strand break repair through nonhomologous end-joining.
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Affiliation(s)
- Swetha Parvathaneni
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, Washington, DC, United States of America
| | - Alexei Stortchevoi
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, Washington, DC, United States of America
| | - Joshua A. Sommers
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Robert M. Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Sudha Sharma
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, Washington, DC, United States of America
- * E-mail:
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Kanungo J. DNA-dependent protein kinase and DNA repair: relevance to Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2013; 5:13. [PMID: 23566654 PMCID: PMC3706827 DOI: 10.1186/alzrt167] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The pathological hallmark of Alzheimer's disease (AD), the leading cause of senile dementia, involves region-specific neuronal death and an accumulation of neuronal and extracellular lesions termed neurofibrillary tangles and senile plaques, respectively. One of the biochemical abnormalities observed in AD is reduced DNA end-joining activity. The reduced capacity of post-mitotic neurons for some types of DNA repair is further compromised by aging. The predominant mechanism to repair double-strand DNA (dsDNA) breaks (DSB) is non-homologous end joining (NHEJ), which requires DNA-dependent protein kinase (DNA-PK) activity. DNA-PK is a holoenzyme comprising the p460 kDa DNA-PK catalytic subunit (DNA-PKcs) and the Ku heterodimer consisting of p86 (Ku 80) and p70 (Ku 70) subunits. Ku binds to DNA ends first and then recruits DNA-PKcs during NHEJ. However, in AD brains, reduced NHEJ activity has been reported along with reduced levels of DNA-PKcs and the Ku proteins, indicating a potential link between AD and dsDNA damage. Since age-matched control brains also show a reduction in these protein levels, whether there is a direct link between NHEJ ability and AD remains unknown. Possible mechanisms involving the role of DNA-PK in neurodegeneration, a benchmark of AD, are the focus of this review.
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Affiliation(s)
- Jyotshna Kanungo
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
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Cottarel J, Frit P, Bombarde O, Salles B, Négrel A, Bernard S, Jeggo PA, Lieber MR, Modesti M, Calsou P. A noncatalytic function of the ligation complex during nonhomologous end joining. ACTA ACUST UNITED AC 2013; 200:173-86. [PMID: 23337116 PMCID: PMC3549972 DOI: 10.1083/jcb.201203128] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ligase IV, but not its catalytic function, is required for DNA-PK–dependent end synapsis during nonhomologous end joining. Nonhomologous end joining is the primary deoxyribonucleic acid (DNA) double-strand break repair pathway in multicellular eukaryotes. To initiate repair, Ku binds DNA ends and recruits the DNA-dependent protein kinase (DNA-PK) catalytic subunit (DNA-PKcs) forming the holoenzyme. Early end synapsis is associated with kinase autophosphorylation. The XRCC4 (X4)–DNA Ligase IV (LIG4) complex (X4LIG4) executes the final ligation promoted by Cernunnos (Cer)–X4-like factor (XLF). In this paper, using a cell-free system that recapitulates end synapsis and DNA-PKcs autophosphorylation, we found a defect in both activities in human cell extracts lacking LIG4. LIG4 also stimulated the DNA-PKcs autophosphorylation in a reconstitution assay with purified components. We additionally uncovered a kinase autophosphorylation defect in LIG4-defective cells that was corrected by ectopic expression of catalytically dead LIG4. Finally, our data support a contribution of Cer-XLF to this unexpected early role of the ligation complex in end joining. We propose that productive end joining occurs by early formation of a supramolecular entity containing both DNA-PK and X4LIG4–Cer-XLF complexes on DNA ends.
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Affiliation(s)
- Jessica Cottarel
- Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, Toulouse F-31077, Cedex 4, France
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Malu S, Malshetty V, Francis D, Cortes P. Role of non-homologous end joining in V(D)J recombination. Immunol Res 2013; 54:233-46. [PMID: 22569912 DOI: 10.1007/s12026-012-8329-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The pathway of V(D)J recombination was discovered almost three decades ago. Yet it continues to baffle scientists because of its inherent complexity and the multiple layers of regulation that are required to efficiently generate a diverse repertoire of T and B cells. The non-homologous end-joining (NHEJ) DNA repair pathway is an integral part of the V(D)J reaction, and its numerous players perform critical functions in generating this vast diversity, while ensuring genomic stability. In this review, we summarize the efforts of a number of laboratories including ours in providing the mechanisms of V(D)J regulation with a focus on the NHEJ pathway. This involves discovering new players, unraveling unknown roles for known components, and understanding how deregulation of these pathways contributes to generation of primary immunodeficiencies. A long-standing interest of our laboratory has been to elucidate various mechanisms that control RAG activity. Our recent work has focused on understanding the multiple protein-protein interactions and protein-DNA interactions during V(D)J recombination, which allow efficient and regulated generation of the antigen receptors. Exploring how deregulation of this process contributes to immunodeficiencies also continues to be an important area of research for our group.
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Affiliation(s)
- Shruti Malu
- Department of Medicine, Immunology Institute, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY 10029, USA
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50
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Abstract
DNA is constantly being damaged from endogenous and exogenous sources and efficient repair of different types of DNA lesions is essential for the survival of the organism. Dictyostelium is highly resistant to DNA damage and its genome sequence has revealed the presence of multiple repair pathways conserved with vertebrates but lost in other genetically tractable invertebrate models. As such, Dictyostelium is a powerful model organism to study selected human DNA repair pathways and may provide insights into the molecular basis of how cells become resistant to DNA damage. Here we describe a range of assays used to study DNA repair in Dictyostelium. Genes required for repair of DNA damage can be identified and analyzed by comparing the ability of control or mutant cells to survive exposure to genotoxic agents that induce different types of DNA lesion. We also describe assays that assess the presence of markers for DNA repair within chromatin either in the form of posttranslational modification of proteins at sites of damage or the recruitment of repair factors to DNA lesions. Finally, we also describe more direct assays to assess repair of DNA double-strand breaks by either homologous recombination or non-homologous end joining.
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