1
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Liu HL, Nan H, Zhao WW, Wan XB, Fan XJ. Phase separation in DNA double-strand break response. Nucleus 2024; 15:2296243. [PMID: 38146123 PMCID: PMC10761171 DOI: 10.1080/19491034.2023.2296243] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 12/12/2023] [Indexed: 12/27/2023] Open
Abstract
DNA double-strand break (DSB) is the most dangerous type of DNA damage, which may lead to cell death or oncogenic mutations. Homologous recombination (HR) and nonhomologous end-joining (NHEJ) are two typical DSB repair mechanisms. Recently, many studies have revealed that liquid-liquid phase separation (LLPS) plays a pivotal role in DSB repair and response. Through LLPS, the crucial biomolecules are quickly recruited to damaged sites with a high concentration to ensure DNA repair is conducted quickly and efficiently, which facilitates DSB repair factors activating downstream proteins or transmitting signals. In addition, the dysregulation of the DSB repair factor's phase separation has been reported to promote the development of a variety of diseases. This review not only provides a comprehensive overview of the emerging roles of LLPS in the repair of DSB but also sheds light on the regulatory patterns of phase separation in relation to the DNA damage response (DDR).
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Affiliation(s)
- Huan-Lei Liu
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China
- Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China
- Academy of Medical Science, Zhengzhou University, Zhengzhou, Henan, P.R. China
- College of Life Sciences, Northwest AF University, Yangling, Shaanxi, China
| | - Hao Nan
- College of Life Sciences, Northwest AF University, Yangling, Shaanxi, China
| | - Wan-Wen Zhao
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China
| | - Xiang-Bo Wan
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China
- Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China
- Academy of Medical Science, Zhengzhou University, Zhengzhou, Henan, P.R. China
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China
| | - Xin-Juan Fan
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, P.R. China
- Academy of Medical Science, Zhengzhou University, Zhengzhou, Henan, P.R. China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China
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2
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Benamar M, Eki R, Du KP, Abbas T. Break-induced replication drives large-scale genomic amplifications in cancer cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609980. [PMID: 39253455 PMCID: PMC11383296 DOI: 10.1101/2024.08.27.609980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that underly the efficacy of ionizing radiation (IR) and a large number of cytotoxic chemotherapies 1-3 . Yet, abnormal repair of DSBs is associated with genomic instability and may contribute to cancer heterogeneity and tumour evolution. Here, we show that DSBs induced by IR, by DSB-inducing chemotherapeutics, or by the expression of a rare-cutting restriction endonuclease induce large-scale genomic amplification in human cancer cells. Importantly, the extent of DSB-induced genomic amplification (DIGA) in a panel of melanoma cell lines correlated with the degree of cytotoxicity elicited by IR, suggesting that DIGA contributes significantly to DSB-induced cancer cell lethality. DIGA, which is mediated through conservative DNA synthesis, does not require origin re-licensing, and is enhanced by the depletion or deletion of the methyltransferases SET8 and SUV4-20H1, which function sequentially to mono- and di-methylate histone H4 lysine 20 (H4K20) at DSBs to facilitate the recruitment of 53BP1-RIF1 and its downstream effector shieldin complex to DSBs to prevent hyper-resection 4-11 . Consistently, DIGA was enhanced in cells lacking 53BP1 or RIF1, or in cells that lacked components of the shieldin complex or of other factors that help recruit 53BP1 to DSBs. Mechanistically, DIGA requires MRE11/CtIP and EXO1, factors that promote resection and hyper-resection at DSBs, and is dependent on the catalytic activity of the RAD51 recombinase. Furthermore, deletion or depletion of POLD3, POLD4, or RAD52, proteins involved in break-induced replication (BIR), significantly inhibited DIGA, suggesting that DIGA is mediated through a RAD51-dependent BIR-like process. DIGA induction was maximal if the cells encountered DSBs in early and mid S-phase, whereas cells competent for homologous recombination (in late S and G2) exhibited less DIGA induction. We propose that unshielded, hyper-resected ends of DSBs may nucleate a replication-like intermediate that enables cytotoxic long-range genomic DNA amplification mediated through BIR.
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3
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Vu DD, Bonucci A, Brenière M, Cisneros-Aguirre M, Pelupessy P, Wang Z, Carlier L, Bouvignies G, Cortes P, Aggarwal AK, Blackledge M, Gueroui Z, Belle V, Stark JM, Modesti M, Ferrage F. Multivalent interactions of the disordered regions of XLF and XRCC4 foster robust cellular NHEJ and drive the formation of ligation-boosting condensates in vitro. Nat Struct Mol Biol 2024:10.1038/s41594-024-01339-x. [PMID: 38898102 DOI: 10.1038/s41594-024-01339-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 05/28/2024] [Indexed: 06/21/2024]
Abstract
In mammalian cells, DNA double-strand breaks are predominantly repaired by non-homologous end joining (NHEJ). During repair, the Ku70-Ku80 heterodimer (Ku), X-ray repair cross complementing 4 (XRCC4) in complex with DNA ligase 4 (X4L4) and XRCC4-like factor (XLF) form a flexible scaffold that holds the broken DNA ends together. Insights into the architectural organization of the NHEJ scaffold and its regulation by the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were recently obtained by single-particle cryo-electron microscopy analysis. However, several regions, especially the C-terminal regions (CTRs) of the XRCC4 and XLF scaffolding proteins, have largely remained unresolved in experimental structures, which hampers the understanding of their functions. Here we used magnetic resonance techniques and biochemical assays to comprehensively characterize the interactions and dynamics of the XRCC4 and XLF CTRs at residue resolution. We show that the CTRs of XRCC4 and XLF are intrinsically disordered and form a network of multivalent heterotypic and homotypic interactions that promotes robust cellular NHEJ activity. Importantly, we demonstrate that the multivalent interactions of these CTRs lead to the formation of XLF and X4L4 condensates in vitro, which can recruit relevant effectors and critically stimulate DNA end ligation. Our work highlights the role of disordered regions in the mechanism and dynamics of NHEJ and lays the groundwork for the investigation of NHEJ protein disorder and its associated condensates inside cells with implications in cancer biology, immunology and the development of genome-editing strategies.
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Affiliation(s)
- Duc-Duy Vu
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Alessio Bonucci
- Aix Marseille Univ, CNRS UMR 7281, BIP Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - Manon Brenière
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille University, Marseille, France
| | - Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Philippe Pelupessy
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Ziqing Wang
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Ludovic Carlier
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Guillaume Bouvignies
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Patricia Cortes
- Department of Molecular, Cellular and Biomedical Sciences, CUNY School of Medicine at City College of New York, New York, NY, USA
| | - Aneel K Aggarwal
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), Grenoble Alpes University, CNRS, CEA, Grenoble, France
| | - Zoher Gueroui
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Valérie Belle
- Aix Marseille Univ, CNRS UMR 7281, BIP Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Mauro Modesti
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille University, Marseille, France.
| | - Fabien Ferrage
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France.
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4
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Kushwah AS, Masood S, Mishra R, Banerjee M. Genetic and epigenetic alterations in DNA repair genes and treatment outcome of chemoradiotherapy in cervical cancer. Crit Rev Oncol Hematol 2024; 194:104240. [PMID: 38122918 DOI: 10.1016/j.critrevonc.2023.104240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/06/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Cervical cancer (CaCx) is the deadliest malignancy among women which is caused by human papillomavirus (HPV) and anthro-demographical/clinicopathological factors. HPV oncoproteins E6 and E7 target p53 and RB (retinoblastoma) protein degradation, Ataxia telangiectasia mutated (ATM), ATM-RAD3-related (ATR) inactivation and subsequent impairment of non-homologous end joining (NHEJ), homologous recombination, and base excision repair pathways. There is also an accumulation of genetic and epigenetic alterations in Tumor Growth Suppressors (TGS), oncogenes, and DNA repair genes leading to increased genome instability and CaCx development. These alterations might be responsible for differential clinical response to Cisplatin-based chemoradiotherapy (CRT) in patients. This review explores HPV-mediated DNA damage as a risk factor in CaCx development, the mechanistic role of genetic and epigenetic alterations in DNA repair genes and their association with CRT and outcome, It also explores new possibilities for the development of genetic and epigenetic-based biomarkers for diagnostic, prognostic, and molecular therapeutic interventions.
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Affiliation(s)
- Atar Singh Kushwah
- Department of Urology and Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York 10029, NY, USA; Molecular & Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow 226007, Uttar Pradesh, India; Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Shireen Masood
- Molecular & Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow 226007, Uttar Pradesh, India
| | - Rajnikant Mishra
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Monisha Banerjee
- Molecular & Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow 226007, Uttar Pradesh, India.
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5
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Amin H, Zahid S, Hall C, Chaplin AK. Cold snapshots of DNA repair: Cryo-EM structures of DNA-PKcs and NHEJ machinery. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2024; 186:1-13. [PMID: 38036101 DOI: 10.1016/j.pbiomolbio.2023.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/03/2023] [Accepted: 11/24/2023] [Indexed: 12/02/2023]
Abstract
The proteins and protein assemblies involved in DNA repair have been the focus of a multitude of structural studies for the past few decades. Historically, the structures of these protein complexes have been resolved by X-ray crystallography. However, more recently with the advancements in cryo-electron microscopy (cryo-EM) ranging from optimising the methodology for sample preparation to the development of improved electron detectors, the focus has shifted from X-ray crystallography to cryo-EM. This methodological transition has allowed for the structural determination of larger, more complex protein assemblies involved in DNA repair pathways and has subsequently led to a deeper understanding of the mechanisms utilised by these fascinating molecular machines. Here, we review some of the key structural advancements that have been gained in the study of non-homologous end joining (NHEJ) by the use of cryo-EM, with a focus on assemblies composed of DNA-PKcs and Ku70/80 (Ku) and the various methodologies utilised to obtain these structures.
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Affiliation(s)
- Himani Amin
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Sayma Zahid
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Chloe Hall
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - 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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6
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Bader AS, Bushell M. iMUT-seq: high-resolution DSB-induced mutation profiling reveals prevalent homologous-recombination dependent mutagenesis. Nat Commun 2023; 14:8419. [PMID: 38110444 PMCID: PMC10728174 DOI: 10.1038/s41467-023-44167-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most mutagenic form of DNA damage, and play a significant role in cancer biology, neurodegeneration and aging. However, studying DSB-induced mutagenesis is limited by our current approaches. Here, we describe iMUT-seq, a technique that profiles DSB-induced mutations at high-sensitivity and single-nucleotide resolution around endogenous DSBs. By depleting or inhibiting 20 DSB-repair factors we define their mutational signatures in detail, revealing insights into the mechanisms of DSB-induced mutagenesis. Notably, we find that homologous-recombination (HR) is more mutagenic than previously thought, inducing prevalent base substitutions and mononucleotide deletions at distance from the break due to DNA-polymerase errors. Simultaneously, HR reduces translocations, suggesting a primary role of HR is specifically the prevention of genomic rearrangements. The results presented here offer fundamental insights into DSB-induced mutagenesis and have significant implications for our understanding of cancer biology and the development of DDR-targeting chemotherapeutics.
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Affiliation(s)
- Aldo S Bader
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Cancer Research UK/CI, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
- The Gurdon Institute, University of Cambridge, Biochemistry, Cambridge, UK.
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK.
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7
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Vogt A, He Y, Lees-Miller SP. How to fix DNA breaks: new insights into the mechanism of non-homologous end joining. Biochem Soc Trans 2023; 51:1789-1800. [PMID: 37787023 PMCID: PMC10657183 DOI: 10.1042/bst20220741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 08/26/2023] [Accepted: 09/22/2023] [Indexed: 10/04/2023]
Abstract
Non-homologous end joining (NHEJ) is the major pathway for the repair of ionizing radiation-induced DNA double-strand breaks (DSBs) in human cells and is essential for the generation of mature T and B cells in the adaptive immune system via the process of V(D)J recombination. Here, we review how recently determined structures shed light on how NHEJ complexes function at DNA DSBs, emphasizing how multiple structures containing the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) may function in NHEJ. Together, these studies provide an explanation for how NHEJ proteins assemble to detect and protect DSB ends, then proceed, through DNA-PKcs-dependent autophosphorylation, to a ligation-competent complex.
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Affiliation(s)
- Alex Vogt
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, U.S.A
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, U.S.A
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, U.S.A
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, U.S.A
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, U.S.A
- Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Northwestern University, Chicago, U.S.A
| | - Susan P. Lees-Miller
- Department of Biochemistry and Molecular Biology, Robson DNA Science Centre and Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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8
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Khan H, Ochi T. Plant PAXX has an XLF-like function and stimulates DNA end joining by the Ku-DNA ligase IV/XRCC4 complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:58-68. [PMID: 37340932 DOI: 10.1111/tpj.16359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/14/2023] [Indexed: 06/22/2023]
Abstract
Non-homologous end joining (NHEJ) plays a major role in repairing DNA double-strand breaks and is key to genome stability and editing. The minimal core NHEJ proteins, namely Ku70, Ku80, DNA ligase IV and XRCC4, are conserved, but other factors vary in different eukaryote groups. In plants, the only known NHEJ proteins are the core factors, while the molecular mechanism of plant NHEJ remains unclear. Here, we report a previously unidentified plant ortholog of PAXX, the crystal structure of which showed a similar fold to human 'PAXX'. However, plant PAXX has similar molecular functions to human XLF, by directly interacting with Ku70/80 and XRCC4. This suggests that plant PAXX combines the roles of mammalian PAXX and XLF and that these functions merged into a single protein during evolution. This is consistent with a redundant function of PAXX and XLF in mammals.
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Affiliation(s)
- Hira Khan
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Takashi Ochi
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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9
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Loparo JJ. Holding it together: DNA end synapsis during non-homologous end joining. DNA Repair (Amst) 2023; 130:103553. [PMID: 37572577 PMCID: PMC10530278 DOI: 10.1016/j.dnarep.2023.103553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/04/2023] [Accepted: 08/06/2023] [Indexed: 08/14/2023]
Abstract
DNA double strand breaks (DSBs) are common lesions whose misrepair are drivers of oncogenic transformations. The non-homologous end joining (NHEJ) pathway repairs the majority of these breaks in vertebrates by directly ligating DNA ends back together. Upon formation of a DSB, a multiprotein complex is assembled on DNA ends which tethers them together within a synaptic complex. Synapsis is a critical step of the NHEJ pathway as loss of synapsis can result in mispairing of DNA ends and chromosome translocations. As DNA ends are commonly incompatible for ligation, the NHEJ machinery must also process ends to enable rejoining. This review describes how recent progress in single-molecule approaches and cryo-EM have advanced our molecular understanding of DNA end synapsis during NHEJ and how synapsis is coordinated with end processing to determine the fidelity of repair.
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Affiliation(s)
- Joseph J Loparo
- Dept. of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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10
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Head PE, Kapoor-Vazirani P, Nagaraju GP, Zhang H, Rath S, Luong N, Haji-Seyed-Javadi R, Sesay F, Wang SY, Duong D, Daddacha W, Minten E, Song B, Danelia D, Liu X, Li S, Ortlund E, Seyfried N, Smalley D, Wang Y, Deng X, Dynan W, El-Rayes B, Davis A, Yu D. DNA-PK is activated by SIRT2 deacetylation to promote DNA double-strand break repair by non-homologous end joining. Nucleic Acids Res 2023; 51:7972-7987. [PMID: 37395399 PMCID: PMC10450170 DOI: 10.1093/nar/gkad549] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 06/02/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK) plays a critical role in non-homologous end joining (NHEJ), the predominant pathway that repairs DNA double-strand breaks (DSB) in response to ionizing radiation (IR) to govern genome integrity. The interaction of the catalytic subunit of DNA-PK (DNA-PKcs) with the Ku70/Ku80 heterodimer on DSBs leads to DNA-PK activation; however, it is not known if upstream signaling events govern this activation. Here, we reveal a regulatory step governing DNA-PK activation by SIRT2 deacetylation, which facilitates DNA-PKcs localization to DSBs and interaction with Ku, thereby promoting DSB repair by NHEJ. SIRT2 deacetylase activity governs cellular resistance to DSB-inducing agents and promotes NHEJ. SIRT2 furthermore interacts with and deacetylates DNA-PKcs in response to IR. SIRT2 deacetylase activity facilitates DNA-PKcs interaction with Ku and localization to DSBs and promotes DNA-PK activation and phosphorylation of downstream NHEJ substrates. Moreover, targeting SIRT2 with AGK2, a SIRT2-specific inhibitor, augments the efficacy of IR in cancer cells and tumors. Our findings define a regulatory step for DNA-PK activation by SIRT2-mediated deacetylation, elucidating a critical upstream signaling event initiating the repair of DSBs by NHEJ. Furthermore, our data suggest that SIRT2 inhibition may be a promising rationale-driven therapeutic strategy for increasing the effectiveness of radiation therapy.
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Affiliation(s)
- PamelaSara E Head
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Priya Kapoor-Vazirani
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Ganji P Nagaraju
- School of Medicine, Division of Hematology and Medical Oncology, University of Alabama, Birmingham, AL 35233, USA
| | - Hui Zhang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Sandip K Rath
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Nho C Luong
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Ramona Haji-Seyed-Javadi
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Fatmata Sesay
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Shi-Ya Wang
- Department of Radiation Oncology, UT Southwestern Medical School, Dallas, TX 75390, USA
| | - Duc M Duong
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Waaqo Daddacha
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA 30912, USA
| | - Elizabeth V Minten
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Boying Song
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Diana Danelia
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Xu Liu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Shuyi Li
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Eric A Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David M Smalley
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Ya Wang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - Xingming Deng
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
| | - William S Dynan
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Bassel El-Rayes
- School of Medicine, Division of Hematology and Medical Oncology, University of Alabama, Birmingham, AL 35233, USA
| | - Anthony J Davis
- Department of Radiation Oncology, UT Southwestern Medical School, Dallas, TX 75390, USA
| | - David S Yu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine,Atlanta, GA 30322, USA
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11
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Hardwick SW, Stavridi AK, Chirgadze DY, De Oliveira TM, Charbonnier JB, Ropars V, Meek K, Blundell TL, Chaplin AK. Cryo-EM structure of a DNA-PK trimer: higher order oligomerisation in NHEJ. Structure 2023; 31:895-902.e3. [PMID: 37311458 DOI: 10.1016/j.str.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/11/2023] [Accepted: 05/18/2023] [Indexed: 06/15/2023]
Abstract
The ability of humans to maintain the integrity of the genome is imperative for cellular survival. DNA double-strand breaks (DSBs) are considered the most critical type of DNA lesion, which can ultimately lead to diseases including cancer. Non-homologous end joining (NHEJ) is one of two core mechanisms utilized to repair DSBs. DNA-PK is a key component in this process and has recently been shown to form alternate long-range synaptic dimers. This has led to the proposal that these complexes can be formed before transitioning to a short-range synaptic complex. Here we present cryo-EM data representing an NHEJ supercomplex consisting of a trimer of DNA-PK in complex with XLF, XRCC4, and DNA Ligase IV. This trimer represents a complex of both long-range synaptic dimers. We discuss the potential role of the trimeric structure, and possible higher order oligomers, as structural intermediates in the NHEJ mechanism, or as functional DNA repair centers.
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Affiliation(s)
- Steven W Hardwick
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, CB2 1GA Cambridge, UK
| | - Antonia Kefala Stavridi
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, CB2 1GA Cambridge, UK
| | - Dimitri Y Chirgadze
- Cryo-EM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, CB2 1GA Cambridge, UK
| | | | - Jean-Baptiste Charbonnier
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, CB2 1GA Cambridge, UK
| | - 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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12
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Geris JM, Amirian ES, Marquez-Do DA, Guillaud M, Dillon LM, Follen M, Scheurer ME. Polymorphisms in the Nonhomologous End-joining DNA Repair Pathway are Associated with HPV Integration in Cervical Dysplasia. Cancer Prev Res (Phila) 2023; 16:461-469. [PMID: 37217238 PMCID: PMC10524768 DOI: 10.1158/1940-6207.capr-23-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/06/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
Previous evidence indicates that human papillomavirus (HPV) integration status may be associated with cervical cancer development and progression. However, host genetic variation within genes that may play important roles in the viral integration process is understudied. The aim of this study was to examine the association between HPV16 and HPV18 viral integration status and SNPs in nonhomologous-end-joining (NHEJ) DNA repair pathway genes on cervical dysplasia. Women enrolled in two large trials of optical technologies for cervical cancer detection and positive for HPV16 or HPV18 were selected for HPV integration analysis and genotyping. Associations between SNPs and cytology (normal, low-grade, or high-grade lesions) were evaluated. Among women with cervical dysplasia, polytomous logistic regression models were used to evaluate the effect of each SNP on viral integration status. Of the 710 women evaluated [149 high-grade squamous intraepithelial lesion (HSIL), 251; low-grade squamous intraepithelial lesion (LSIL, 310 normal)], 395 (55.6%) were positive for HPV16 and 192 (27%) were positive for HPV18. Tag-SNPs in 13 DNA repair genes, including RAD50, WRN, and XRCC4, were significantly associated with cervical dysplasia. HPV16 integration status was differential across cervical cytology, but overall, most participants had a mix of both episomal and integrated HPV16. Four tag-SNPs in the XRCC4 gene were found to be significantly associated with HPV16 integration status. Our findings indicate that host genetic variation in NHEJ DNA repair pathway genes, specifically XRCC4, are significantly associated with HPV integration, and that these genes may play an important role in determining cervical cancer development and progression. PREVENTION RELEVANCE HPV integration in premalignant lesions and is thought to be an important driver of carcinogenesis. However, it is unclear what factors promote integration. The use of targeted genotyping among women presenting with cervical dysplasia has the potential to be an effective tool in assessing the likelihood of progression to cancer.
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Affiliation(s)
- Jennifer M Geris
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - E Susan Amirian
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | | | - Martial Guillaud
- Department of Cancer Imaging, British Columbia Cancer Research Centre, Vancouver, British Columbia
| | - Laura M Dillon
- Department of Diagnostic and Biomedical Sciences, UTHealth School of Dentistry, Houston, Texas
| | | | - Michael E Scheurer
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
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13
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Vu DD, Bonucci A, Brenière M, Cisneros-Aguirre M, Pelupessy P, Wang Z, Carlier L, Bouvignies G, Cortes P, Aggarwal AK, Blackledge M, Gueroui Z, Belle V, Stark JM, Modesti M, Ferrage F. Multivalent interactions of the disordered regions of XLF and XRCC4 foster robust cellular NHEJ and drive the formation of ligation-boosting condensates in vitro. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548668. [PMID: 37503201 PMCID: PMC10369993 DOI: 10.1101/2023.07.12.548668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
In mammalian cells, DNA double-strand breaks are predominantly repaired by non-homologous end joining (NHEJ). During repair, the Ku70/80 heterodimer (Ku), XRCC4 in complex with DNA Ligase 4 (X4L4), and XLF form a flexible scaffold that holds the broken DNA ends together. Insights into the architectural organization of the NHEJ scaffold and its regulation by the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) have recently been obtained by single-particle cryo-electron microscopy analysis. However, several regions, especially the C-terminal regions (CTRs) of the XRCC4 and XLF scaffolding proteins, have largely remained unresolved in experimental structures, which hampers the understanding of their functions. Here, we used magnetic resonance techniques and biochemical assays to comprehensively characterize the interactions and dynamics of the XRCC4 and XLF CTRs at atomic resolution. We show that the CTRs of XRCC4 and XLF are intrinsically disordered and form a network of multivalent heterotypic and homotypic interactions that promotes robust cellular NHEJ activity. Importantly, we demonstrate that the multivalent interactions of these CTRs led to the formation of XLF and X4L4 condensates in vitro which can recruit relevant effectors and critically stimulate DNA end ligation. Our work highlights the role of disordered regions in the mechanism and dynamics of NHEJ and lays the groundwork for the investigation of NHEJ protein disorder and its associated condensates inside cells with implications in cancer biology, immunology and the development of genome editing strategies.
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Affiliation(s)
- Duc-Duy Vu
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Alessio Bonucci
- Aix Marseille Univ, CNRS UMR 7281, BIP Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - Manon Brenière
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille Univ, Marseille, France
| | - Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Philippe Pelupessy
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Ziqing Wang
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Ludovic Carlier
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Guillaume Bouvignies
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
| | - Patricia Cortes
- Department of Molecular, Cellular and Biomedical Sciences, CUNY School of Medicine at City College of New York, 160 Convent Avenue, New York, NY 10029, USA
| | - Aneel K Aggarwal
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA
| | - Martin Blackledge
- University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Zoher Gueroui
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris, France
| | - Valérie Belle
- Aix Marseille Univ, CNRS UMR 7281, BIP Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Mauro Modesti
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille Univ, Marseille, France
| | - Fabien Ferrage
- Département de Chimie, LBM, CNRS UMR 7203, École Normale Supérieure, PSL University, Sorbonne University, Paris, France
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14
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Watanabe G, Lieber MR. The flexible and iterative steps within the NHEJ pathway. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:105-119. [PMID: 37150451 PMCID: PMC10205690 DOI: 10.1016/j.pbiomolbio.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Cellular and biochemical studies of nonhomologous DNA end joining (NHEJ) have long established that nuclease and polymerase action are necessary for the repair of a very large fraction of naturally-arising double-strand breaks (DSBs). This conclusion is derived from NHEJ studies ranging from yeast to humans and all genetically-tractable model organisms. Biochemical models derived from recent real-time and structural studies have yet to incorporate physical space or timing for DNA end processing. In real-time single molecule FRET (smFRET) studies, we analyzed NHEJ synapsis of DNA ends in a defined biochemical system. We described a Flexible Synapsis (FS) state in which the DNA ends were in proximity via only Ku and XRCC4:DNA ligase 4 (X4L4), and in an orientation that would not yet permit ligation until base pairing between one or more nucleotides of microhomology (MH) occurred, thereby allowing an in-line Close Synapsis (CS) state. If no MH was achievable, then XLF was critical for ligation. Neither FS or CS required DNA-PKcs, unless Artemis activation was necessary to permit local resection and subsequent base pairing between the two DNA ends being joined. Here we conjecture on possible 3D configurations for this FS state, which would spatially accommodate the nuclease and polymerase processing steps in an iterative manner. The FS model permits repeated attempts at ligation of at least one strand at the DSB after each round of nuclease or polymerase action. In addition to activation of Artemis, other possible roles for DNA-PKcs are discussed.
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Affiliation(s)
- Go Watanabe
- Departments of Pathology, Biochemistry, Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), University of Southern California, Los Angeles, CA, 90089-9176, USA
| | - Michael R Lieber
- Departments of Pathology, Biochemistry, Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), University of Southern California, Los Angeles, CA, 90089-9176, USA.
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15
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Yang JH, Brandão HB, Hansen AS. DNA double-strand break end synapsis by DNA loop extrusion. Nat Commun 2023; 14:1913. [PMID: 37024496 PMCID: PMC10079674 DOI: 10.1038/s41467-023-37583-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/23/2023] [Indexed: 04/08/2023] Open
Abstract
DNA double-strand breaks (DSBs) occur every cell cycle and must be efficiently repaired. Non-homologous end joining (NHEJ) is the dominant pathway for DSB repair in G1-phase. The first step of NHEJ is to bring the two DSB ends back into proximity (synapsis). Although synapsis is generally assumed to occur through passive diffusion, we show that passive diffusion is unlikely to produce the synapsis speed observed in cells. Instead, we hypothesize that DNA loop extrusion facilitates synapsis. By combining experimentally constrained simulations and theory, we show that a simple loop extrusion model constrained by previous live-cell imaging data only modestly accelerates synapsis. Instead, an expanded loop extrusion model with targeted loading of loop extruding factors (LEFs), a small portion of long-lived LEFs, and LEF stabilization by boundary elements and DSB ends achieves fast synapsis with near 100% efficiency. We propose that loop extrusion contributes to DSB repair by mediating fast synapsis.
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Affiliation(s)
- Jin H Yang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA
| | - Hugo B Brandão
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA.
- Illumina Inc., San Diego, CA, 92122, USA.
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA.
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16
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Singh Kushwah A, Srivastava K, Banerjee M. Differential expression of DNA repair genes and treatment outcome of chemoradiotherapy (CRT) in cervical cancer. Gene 2023; 868:147389. [PMID: 36963733 DOI: 10.1016/j.gene.2023.147389] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 03/26/2023]
Abstract
Cervical cancer (CaCx) is the malignancy of uterine cervix which induce by human papillomavirus (HPV) infections. HPV infection starts with the induction of double-stranded breaks by increasing oxidative stress and modulation of DNA repair pathways. Deficiency in DNA repair pathways and accumulation of DNA damage increases mutation rates resulting in genomic instability and cancer development. Patients with HPV-associated CaCx display increased sensitivity to cisplatin-based chemoradiotherapy (CRT) and improved survival rates. However, the cellular mechanisms responsible for this characteristic difference are unclear. Here, we have evaluated expression of DNA repair genes in peripheral blood cells and correlated them with treatment outcomes. A total of 211 study subjects includes in the study comprised 103 CaCx patients and 108 healthy controls. All the study subjects were analyzed for the expression profile of DNA repair genes by using real-time PCR (RT-PCR). The differentially expressed DNA repair gene was correlated with the treatment outcome of CRT. OGG1, XRCC2, XRCC3, XRCC4 and XRCC6 genes were found to be significant (P=0.001) down-regulated as compared to controls. While XRCC5 and RAD51 showed significant up-regulated (P=0.024 and 0.041) in CaCx patients. XRCC6 was associated (P=0.033) with poor vital while up-regulated RAD51 showed slight association (P=0.075) with better vital with an increased 2.96- and 2.33-fold risk in the study population. In the case of overall survival, down-regulated XRCC4 was associated (P=0.042) with poor survival (27 months) with the least hazard ratio (0.56 HR). Down-regulated OGG1 involved BER, XRCC2 and XRCC3 in homologous recombination and XRCC4, XRCC5 and XRCC6 in Non-homologous end-joining repair, which showed a deficiency of DNA repair capacity resulting caused of an accumulation of DNA damage and genome instability. Impaired DNA repair gene expression is responsible for poor prognosis and survival in CaCx. Therefore, these gene expressions can be considered a potential prognostic, diagnostic and therapeutic biomarker for CaCx.
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Affiliation(s)
- Atar Singh Kushwah
- Molecular and Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow-226007, Uttar Pradesh, India; Center for NanoBiotechnology Research, Department of Biological Sciences, Alabama State University, Montgomery, AL 36104, USA
| | - Kirti Srivastava
- Department of Radiotherapy, King George's Medical University, Lucknow-226003, Uttar Pradesh, India
| | - Monisha Banerjee
- Molecular and Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow-226007, Uttar Pradesh, India.
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17
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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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18
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De Bragança S, Aicart-Ramos C, Arribas-Bosacoma R, Rivera-Calzada A, Unfried JP, Prats-Mari L, Marin-Baquero M, Fortes P, Llorca O, Moreno-Herrero F. APLF and long non-coding RNA NIHCOLE promote stable DNA synapsis in non-homologous end joining. Cell Rep 2023; 42:111917. [PMID: 36640344 DOI: 10.1016/j.celrep.2022.111917] [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: 06/08/2022] [Revised: 10/26/2022] [Accepted: 12/13/2022] [Indexed: 01/01/2023] Open
Abstract
The synapsis of DNA ends is a critical step for the repair of double-strand breaks by non-homologous end joining (NHEJ). This is performed by a multicomponent protein complex assembled around Ku70-Ku80 heterodimers and regulated by accessory factors, including long non-coding RNAs, through poorly understood mechanisms. Here, we use magnetic tweezers to investigate the contributions of core NHEJ proteins and APLF and lncRNA NIHCOLE to DNA synapsis. APLF stabilizes DNA end bridging and, together with Ku70-Ku80, establishes a minimal complex that supports DNA synapsis for several minutes under piconewton forces. We find the C-terminal acidic region of APLF to be critical for bridging. NIHCOLE increases the dwell time of the synapses by Ku70-Ku80 and APLF. This effect is further enhanced by a small and structured RNA domain within NIHCOLE. We propose a model where Ku70-Ku80 can simultaneously bind DNA, APLF, and structured RNAs to promote the stable joining of DNA ends.
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Affiliation(s)
- Sara De Bragança
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Raquel Arribas-Bosacoma
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Angel Rivera-Calzada
- Structural Biology Programme, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Juan Pablo Unfried
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel; Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain
| | - Laura Prats-Mari
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain
| | - Mikel Marin-Baquero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain
| | - Puri Fortes
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra (UNAV), Pamplona, Spain; Navarra Institute for Health Research (IdiSNA), Pamplona, Spain; Liver and Digestive Diseases Networking Biomedical Research Centre (CIBERehd), Spanish Network for Advanced Therapies (TERAV ISCIII), Madrid, Spain
| | - Oscar Llorca
- Structural Biology Programme, Spanish National Cancer Research Center (CNIO), Madrid, Spain.
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Madrid, Spain.
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19
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Yang X, Yang F, Lan L, Wen N, Li H, Sun X. Potential value of PRKDC as a therapeutic target and prognostic biomarker in pan-cancer. Medicine (Baltimore) 2022; 101:e29628. [PMID: 35801800 PMCID: PMC9259106 DOI: 10.1097/md.0000000000029628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND While protein kinase, DNA-activated, catalytic subunit (PRKDC) plays an important role in double-strand break repair to retain genomic stability, there is still no pan-cancer analysis based on large clinical information on the relationship between PRKDC and different tumors. For the first time, this research used numerous databases to perform a pan-cancer review for PRKDC to explore the possible mechanism of PRKDC in the etiology and outcomes in various tumors. METHODS PRKDC's expression profile and prognostic significance in pan-cancer were investigated based on various databases and online platforms, including TIMER2, GEPIA2, cBioPortal, CPTAC, and SangerBox. We applied the TIMER to identified the interlink of PRKDC and the immune infiltration in assorted tumors, and the SangerBox online platform was adopted to find out the relevance between PRKDC and immune checkpoint genes, tumor mutation burden, and microsatellite instability in tumors. GeneMANIA tool was employed to create a protein-protein interaction analysis, gene set enrichment analysis was conducted to performed gene enrichment analysis. RESULTS Overall, tumor tissue presented a higher degree of PRKDC expression than adjacent normal tissue. Meanwhile, patients with high PRKDC expression have a worse prognosis. PRKDC mutations were present in almost all The Cancer Genome Atlas tumors and might lead to a better survival prognosis. The PRKDC expression level was shown a positive correlation with tumor-infiltrating immune cells. PRKDC high expression cohorts were enriched in "cell cycle" "oocyte meiosis" and "RNA-degradation" signaling pathways. CONCLUSIONS This study revealed the potential value of PRKDC in tumor immunology and as a therapeutic target and prognostic biomarker in pan-cancer.
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Affiliation(s)
- Xiawei Yang
- Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Feng Yang
- Department of Gynocology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Liugen Lan
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Ning Wen
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Haibin Li
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
| | - Xuyong Sun
- Transplant Medical Center, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory of Organ Donation and Transplantation, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Key Laboratory for Transplantation Medicine, Nanning, Guangxi Zhuang Autonomous Region, China
- Guangxi Transplantation Medicine Research Center of Engineering Technology, Nanning, Guangxi Zhuang Autonomous Region, China
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20
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Shams F, Bayat H, Mohammadian O, Mahboudi S, Vahidnezhad H, Soosanabadi M, Rahimpour A. Advance trends in targeting homology-directed repair for accurate gene editing: An inclusive review of small molecules and modified CRISPR-Cas9 systems. BIOIMPACTS 2022; 12:371-391. [PMID: 35975201 PMCID: PMC9376165 DOI: 10.34172/bi.2022.23871] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/21/2021] [Accepted: 11/21/2021] [Indexed: 11/25/2022]
Abstract
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Introduction: Clustered regularly interspaced short palindromic repeat and its associated protein (CRISPR-Cas)-based technologies generate targeted modifications in host genome by inducing site-specific double-strand breaks (DSBs) that can serve as a substrate for homology-directed repair (HDR) in both in vitro and in vivo models. HDR pathway could enhance incorporation of exogenous DNA templates into the CRISPR-Cas9-mediated DSB site. Owing to low rate of HDR pathway, the efficiency of accurate genome editing is diminished. Enhancing the efficiency of HDR can provide fast, easy, and accurate technologies based on CRISPR-Cas9 technologies.
Methods: The current study presents an overview of attempts conducted on the precise genome editing strategies based on small molecules and modified CRISPR-Cas9 systems.
Results: In order to increase HDR rate in targeted cells, several logical strategies have been introduced such as generating CRISPR effector chimeric proteins, anti-CRISPR proteins, modified Cas9 with donor template, and using validated synthetic or natural small molecules for either inhibiting non-homologous end joining (NHEJ), stimulating HDR, or synchronizing cell cycle. Recently, high-throughput screening methods have been applied for identification of small molecules which along with the CRISPR system can regulate precise genome editing through HDR.
Conclusion: The stimulation of HDR components or inhibiting NHEJ can increase the accuracy of CRISPR-Cas-mediated engineering systems. Generating chimeric programmable endonucleases provide this opportunity to direct DNA template close proximity of CRISPR-Cas-mediated DSB. Small molecules and their derivatives can also proficiently block or activate certain DNA repair pathways and bring up novel perspectives for increasing HDR efficiency, especially in human cells. Further, high throughput screening of small molecule libraries could result in more discoveries of promising chemicals that improve HDR efficiency and CRISPR-Cas9 systems.
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Affiliation(s)
- Forough Shams
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hadi Bayat
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omid Mohammadian
- Medical Nano-Technology and Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Somayeh Mahboudi
- Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Mohsen Soosanabadi
- Department of Medical Genetics, Semnan University of Medical Sciences, Semnan, Iran
| | - Azam Rahimpour
- Medical Nano-Technology and Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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21
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Small-molecule enhancers of CRISPR-induced homology-directed repair in gene therapy: A medicinal chemist's perspective. Drug Discov Today 2022; 27:2510-2525. [PMID: 35738528 DOI: 10.1016/j.drudis.2022.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/19/2022] [Accepted: 06/16/2022] [Indexed: 11/20/2022]
Abstract
CRISPR technologies are increasingly being investigated and utilized for the treatment of human genetic diseases via genome editing. CRISPR-Cas9 first generates a targeted DNA double-stranded break, and a functional gene can then be introduced to replace the defective copy in a precise manner by templated repair via the homology-directed repair (HDR) pathway. However, this is challenging owing to the relatively low efficiency of the HDR pathway compared with a rival random repair pathway known as non-homologous end joining (NHEJ). Small molecules can be employed to increase the efficiency of HDR and decrease that of NHEJ to improve the efficiency of precise knock-in genome editing. This review discusses the potential usage of such small molecules in the context of gene therapy and their drug-likeness, from a medicinal chemist's perspective.
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22
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Cabello-Lobato MJ, Jenner M, Cisneros-Aguirre M, Brüninghoff K, Sandy Z, da Costa I, Jowitt T, Loch C, Jackson S, Wu Q, Mootz H, Stark J, Cliff M, Schmidt C. Microarray screening reveals two non-conventional SUMO-binding modules linked to DNA repair by non-homologous end-joining. Nucleic Acids Res 2022; 50:4732-4754. [PMID: 35420136 PMCID: PMC9071424 DOI: 10.1093/nar/gkac237] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 03/03/2022] [Accepted: 03/25/2022] [Indexed: 11/25/2022] Open
Abstract
SUMOylation is critical for numerous cellular signalling pathways, including the maintenance of genome integrity via the repair of DNA double-strand breaks (DSBs). If misrepaired, DSBs can lead to cancer, neurodegeneration, immunodeficiency and premature ageing. Using systematic human proteome microarray screening combined with widely applicable carbene footprinting, genetic code expansion and high-resolution structural profiling, we define two non-conventional and topology-selective SUMO2-binding regions on XRCC4, a DNA repair protein important for DSB repair by non-homologous end-joining (NHEJ). Mechanistically, the interaction of SUMO2 and XRCC4 is incompatible with XRCC4 binding to three other proteins important for NHEJ-mediated DSB repair. These findings are consistent with SUMO2 forming a redundant NHEJ layer with the potential to regulate different NHEJ complexes at distinct levels including, but not limited to, XRCC4 interactions with XLF, LIG4 and IFFO1. Regulation of NHEJ is not only relevant for carcinogenesis, but also for the design of precision anti-cancer medicines and the optimisation of CRISPR/Cas9-based gene editing. In addition to providing molecular insights into NHEJ, this work uncovers a conserved SUMO-binding module and provides a rich resource on direct SUMO binders exploitable towards uncovering SUMOylation pathways in a wide array of cellular processes.
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Affiliation(s)
- Maria Jose Cabello-Lobato
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK
| | - Matthew Jenner
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
- Warwick Integrative Synthetic Biology (WISB) Centre, University of Warwick, Coventry CV4 7AL, UK
| | - Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences Beckman Research Institute of the City of Hope, 1500 E Duarte Rd, Duarte, CA 91010, USA
| | - Kira Brüninghoff
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149 Muenster, Germany
| | - Zac Sandy
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK
| | - Isabelle C da Costa
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK
| | - Thomas A Jowitt
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | | - Stephen P Jackson
- Wellcome/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK
| | - Qian Wu
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Henning D Mootz
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149 Muenster, Germany
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Irell and Manella Graduate School of Biological Sciences Beckman Research Institute of the City of Hope, 1500 E Duarte Rd, Duarte, CA 91010, USA
| | - Matthew J Cliff
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, University of Manchester, Manchester M1 7DN, UK
| | - Christine K Schmidt
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, UK
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23
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WASH interacts with Ku to regulate DNA double-stranded break repair. iScience 2022; 25:103676. [PMID: 35036867 PMCID: PMC8749218 DOI: 10.1016/j.isci.2021.103676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/12/2021] [Accepted: 12/20/2021] [Indexed: 12/28/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein and SCAR homolog (WASH), an actin nucleation-promoting factor, is present in the nucleus where it regulates gene transcription and maintains nuclear organization. Here, we show that WASH interacts with core non-homologous end-joining (NHEJ) factors including Ku70/Ku80 and DNA-PKcs, and Ku70/Ku80 is involved in the recruitment of WASH to the sites of DNA double-stranded break (DSB). WASH depletion leads to increased cell sensitivity and impaired DNA repair capacity in response to etoposide-induced DSBs and reduces NHEJ efficiency. Mechanistically, we show that loss of WASH inhibits the phosphorylation of DNA-PKcs, H2AX, and KAP1 after DSB induction and reduces chromatin relaxation and the recruitment of several downstream NHEJ factors to DSBs. Moreover, WASH role in DSB repair depends on its conserved C-terminal VCA domain and Arp2/3 activation. Our findings reveal a function and mechanistic insight for WASH in DNA DSB repair by the NHEJ pathway.
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24
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Kong M, Greene EC. Mechanistic Insights From Single-Molecule Studies of Repair of Double Strand Breaks. Front Cell Dev Biol 2021; 9:745311. [PMID: 34869333 PMCID: PMC8636147 DOI: 10.3389/fcell.2021.745311] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/28/2021] [Indexed: 01/01/2023] Open
Abstract
DNA double strand breaks (DSBs) are among some of the most deleterious forms of DNA damage. Left unrepaired, they are detrimental to genome stability, leading to high risk of cancer. Two major mechanisms are responsible for the repair of DSBs, homologous recombination (HR) and nonhomologous end joining (NHEJ). The complex nature of both pathways, involving a myriad of protein factors functioning in a highly coordinated manner at distinct stages of repair, lend themselves to detailed mechanistic studies using the latest single-molecule techniques. In avoiding ensemble averaging effects inherent to traditional biochemical or genetic methods, single-molecule studies have painted an increasingly detailed picture for every step of the DSB repair processes.
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Affiliation(s)
| | - Eric C. Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, United States
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25
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Valikhani M, Rahimian E, Ahmadi SE, Chegeni R, Safa M. Involvement of classic and alternative non-homologous end joining pathways in hematologic malignancies: targeting strategies for treatment. Exp Hematol Oncol 2021; 10:51. [PMID: 34732266 PMCID: PMC8564991 DOI: 10.1186/s40164-021-00242-1] [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: 08/16/2021] [Accepted: 10/13/2021] [Indexed: 12/31/2022] Open
Abstract
Chromosomal translocations are the main etiological factor of hematologic malignancies. These translocations are generally the consequence of aberrant DNA double-strand break (DSB) repair. DSBs arise either exogenously or endogenously in cells and are repaired by major pathways, including non-homologous end-joining (NHEJ), homologous recombination (HR), and other minor pathways such as alternative end-joining (A-EJ). Therefore, defective NHEJ, HR, or A-EJ pathways force hematopoietic cells toward tumorigenesis. As some components of these repair pathways are overactivated in various tumor entities, targeting these pathways in cancer cells can sensitize them, especially resistant clones, to radiation or chemotherapy agents. However, targeted therapy-based studies are currently underway in this area, and furtherly there are some biological pitfalls, clinical issues, and limitations related to these targeted therapies, which need to be considered. This review aimed to investigate the alteration of DNA repair elements of C-NHEJ and A-EJ in hematologic malignancies and evaluate the potential targeted therapies against these pathways.
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Affiliation(s)
- Mohsen Valikhani
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Elahe Rahimian
- Department of Medical Translational Oncology, National Center for Tumor Diseases (NCT) Dresden, Dresden, Germany
| | - Seyed Esmaeil Ahmadi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Rouzbeh Chegeni
- Medical Laboratory Sciences, Program, College of Health and Human Sciences, Northern Illinois University, DeKalb, IL, USA
| | - Majid Safa
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran.
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26
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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27
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Chen BR, Wang Y, Shen ZJ, Bennett A, Hindi I, Tyler JK, Sleckman BP. The RNF8 and RNF168 Ubiquitin Ligases Regulate Pro- and Anti-Resection Activities at Broken DNA Ends During Non-Homologous End Joining. DNA Repair (Amst) 2021; 108:103217. [PMID: 34481157 PMCID: PMC9586520 DOI: 10.1016/j.dnarep.2021.103217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/30/2022]
Abstract
The RING-type E3 ubiquitin ligases RNF8 and RNF168 recruit DNA damage response (DDR) factors to chromatin flanking DNA double strand breaks (DSBs) including 53BP1, which protects DNA ends from resection during DNA DSB repair by non-homologous end joining (NHEJ). Deficiency of RNF8 or RNF168 does not lead to demonstrable NHEJ defects, but like deficiency of 53BP1, the combined deficiency of XLF and RNF8 or RNF168 leads to diminished NHEJ in lymphocytes arrested in G0/G1 phase. The function of RNF8 in NHEJ depends on its E3 ubiquitin ligase activity. Loss of RNF8 or RNF168 in G0/G1-phase lymphocytes leads to the resection of broken DNA ends, demonstrating that RNF8 and RNF168 function to protect DNA ends from nucleases, pos sibly through the recruitment of 53BP1. However, the loss of 53BP1 leads to more severe resection than the loss of RNF8 or RNF168. Moreover, in 53BP1-deficient cells, the loss of RNF8 or RNF168 leads to diminished DNA end resection. We conclude that RNF8 and RNF168 regulate pathways that both prevent and promote DNA end resection in cells arrested in G0/G1 phase.
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Affiliation(s)
- Bo-Ruei Chen
- Division of Hematology and Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35233, United States; O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, 35233, United States
| | - Yinan Wang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, United States
| | - Zih-Jie Shen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, United States
| | - Amelia Bennett
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, United States
| | - Issa Hindi
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, United States
| | - Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, United States
| | - Barry P Sleckman
- Division of Hematology and Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35233, United States; O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, 35233, United States.
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28
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Host genetic control of natural killer cell diversity revealed in the Collaborative Cross. Proc Natl Acad Sci U S A 2021; 118:2018834118. [PMID: 33649222 DOI: 10.1073/pnas.2018834118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Natural killer (NK) cells are innate effectors armed with cytotoxic and cytokine-secreting capacities whose spontaneous antitumor activity is key to numerous immunotherapeutic strategies. However, current mouse models fail to mirror the extensive immune system variation that exists in the human population which may impact on NK cell-based therapies. We performed a comprehensive profiling of NK cells in the Collaborative Cross (CC), a collection of novel recombinant inbred mouse strains whose genetic diversity matches that of humans, thereby providing a unique and highly diverse small animal model for the study of immune variation. We demonstrate that NK cells from CC strains displayed a breadth of phenotypic and functional variation reminiscent of that reported for humans with regards to cell numbers, key marker expression, and functional capacities. We took advantage of the vast genetic diversity of the CC and identified nine genomic loci through quantitative trait locus mapping driving these phenotypic variations. SNP haplotype patterns and variant effect analyses identified candidate genes associated with lung NK cell numbers, frequencies of CD94+ NK cells, and expression levels of NKp46. Thus, we demonstrate that the CC represents an outstanding resource to study NK cell diversity and its regulation by host genetics.
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29
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Liang S, Chaplin AK, Stavridi AK, Appleby R, Hnizda A, Blundell TL. Stages, scaffolds and strings in the spatial organisation of non-homologous end joining: Insights from X-ray diffraction and Cryo-EM. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 163:60-73. [PMID: 33285184 PMCID: PMC8224183 DOI: 10.1016/j.pbiomolbio.2020.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/26/2020] [Indexed: 01/10/2023]
Abstract
Non-homologous end joining (NHEJ) is the preferred pathway for the repair of DNA double-strand breaks in humans. Here we describe three structural aspects of the repair pathway: stages, scaffolds and strings. We discuss the orchestration of DNA repair to guarantee robust and efficient NHEJ. We focus on structural studies over the past two decades, not only using X-ray diffraction, but also increasingly exploiting cryo-EM to investigate the macromolecular assemblies.
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Affiliation(s)
- Shikang Liang
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK
| | - Amanda K Chaplin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK
| | - Antonia Kefala Stavridi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK
| | - Robert Appleby
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK
| | - Ales Hnizda
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, Cambridgeshire, UK.
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30
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Matsumoto Y, Asa ADDC, Modak C, Shimada M. DNA-Dependent Protein Kinase Catalytic Subunit: The Sensor for DNA Double-Strand Breaks Structurally and Functionally Related to Ataxia Telangiectasia Mutated. Genes (Basel) 2021; 12:genes12081143. [PMID: 34440313 PMCID: PMC8394720 DOI: 10.3390/genes12081143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 11/16/2022] Open
Abstract
The DNA-dependent protein kinase (DNA-PK) is composed of a DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Ku70/Ku80 heterodimer. DNA-PK is thought to act as the “sensor” for DNA double-stranded breaks (DSB), which are considered the most deleterious type of DNA damage. In particular, DNA-PKcs and Ku are shown to be essential for DSB repair through nonhomologous end joining (NHEJ). The phenotypes of animals and human individuals with defective DNA-PKcs or Ku functions indicate their essential roles in these developments, especially in neuronal and immune systems. DNA-PKcs are structurally related to Ataxia–telangiectasia mutated (ATM), which is also implicated in the cellular responses to DSBs. DNA-PKcs and ATM constitute the phosphatidylinositol 3-kinase-like kinases (PIKKs) family with several other molecules. Here, we review the accumulated knowledge on the functions of DNA-PKcs, mainly based on the phenotypes of DNA-PKcs-deficient cells in animals and human individuals, and also discuss its relationship with ATM in the maintenance of genomic stability.
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31
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Autophosphorylation and Self-Activation of DNA-Dependent Protein Kinase. Genes (Basel) 2021; 12:genes12071091. [PMID: 34356107 PMCID: PMC8305690 DOI: 10.3390/genes12071091] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/11/2021] [Accepted: 07/17/2021] [Indexed: 11/28/2022] Open
Abstract
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a member of the phosphatidylinositol 3-kinase-related kinase family, phosphorylates serine and threonine residues of substrate proteins in the presence of the Ku complex and double-stranded DNA. Although it has been established that DNA-PKcs is involved in non-homologous end-joining, a DNA double-strand break repair pathway, the mechanisms underlying DNA-PKcs activation are not fully understood. Nevertheless, the findings of numerous in vitro and in vivo studies have indicated that DNA-PKcs contains two autophosphorylation clusters, PQR and ABCDE, as well as several autophosphorylation sites and conformational changes associated with autophosphorylation of DNA-PKcs are important for self-activation. Consistent with these features, an analysis of transgenic mice has shown that the phenotypes of DNA-PKcs autophosphorylation mutations are significantly different from those of DNA-PKcs kinase-dead mutations, thereby indicating the importance of DNA-PKcs autophosphorylation in differentiation and development. Furthermore, there has been notable progress in the high-resolution analysis of the conformation of DNA-PKcs, which has enabled us to gain a visual insight into the steps leading to DNA-PKcs activation. This review summarizes the current progress in the activation of DNA-PKcs, focusing in particular on autophosphorylation of this kinase.
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32
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Hammel M, Tainer JA. X-ray scattering reveals disordered linkers and dynamic interfaces in complexes and mechanisms for DNA double-strand break repair impacting cell and cancer biology. Protein Sci 2021; 30:1735-1756. [PMID: 34056803 PMCID: PMC8376411 DOI: 10.1002/pro.4133] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 12/17/2022]
Abstract
Evolutionary selection ensures specificity and efficiency in dynamic metastable macromolecular machines that repair DNA damage without releasing toxic and mutagenic intermediates. Here we examine non‐homologous end joining (NHEJ) as the primary conserved DNA double‐strand break (DSB) repair process in human cells. NHEJ has exemplary key roles in networks determining the development, outcome of cancer treatments by DSB‐inducing agents, generation of antibody and T‐cell receptor diversity, and innate immune response for RNA viruses. We determine mechanistic insights into NHEJ structural biochemistry focusing upon advanced small angle X‐ray scattering (SAXS) results combined with X‐ray crystallography (MX) and cryo‐electron microscopy (cryo‐EM). SAXS coupled to atomic structures enables integrated structural biology for objective quantitative assessment of conformational ensembles and assemblies in solution, intra‐molecular distances, structural similarity, functional disorder, conformational switching, and flexibility. Importantly, NHEJ complexes in solution undergo larger allosteric transitions than seen in their cryo‐EM or MX structures. In the long‐range synaptic complex, X‐ray repair cross‐complementing 4 (XRCC4) plus XRCC4‐like‐factor (XLF) form a flexible bridge and linchpin for DNA ends bound to KU heterodimer (Ku70/80) and DNA‐PKcs (DNA‐dependent protein kinase catalytic subunit). Upon binding two DNA ends, auto‐phosphorylation opens DNA‐PKcs dimer licensing NHEJ via concerted conformational transformations of XLF‐XRCC4, XLF–Ku80, and LigIVBRCT–Ku70 interfaces. Integrated structures reveal multifunctional roles for disordered linkers and modular dynamic interfaces promoting DSB end processing and alignment into the short‐range complex for ligation by LigIV. Integrated findings define dynamic assemblies fundamental to designing separation‐of‐function mutants and allosteric inhibitors targeting conformational transitions in multifunctional complexes.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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33
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Jensen RB, Rothenberg E. Preserving genome integrity in human cells via DNA double-strand break repair. Mol Biol Cell 2021; 31:859-865. [PMID: 32286930 PMCID: PMC7185975 DOI: 10.1091/mbc.e18-10-0668] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The efficient maintenance of genome integrity in the face of cellular stress is vital to protect against human diseases such as cancer. DNA replication, chromatin dynamics, cellular signaling, nuclear architecture, cell cycle checkpoints, and other cellular activities contribute to the delicate spatiotemporal control that cells utilize to regulate and maintain genome stability. This perspective will highlight DNA double-strand break (DSB) repair pathways in human cells, how DNA repair failures can lead to human disease, and how PARP inhibitors have emerged as a novel clinical therapy to treat homologous recombination-deficient tumors. We briefly discuss how failures in DNA repair produce a permissive genetic environment in which preneoplastic cells evolve to reach their full tumorigenic potential. Finally, we conclude that an in-depth understanding of DNA DSB repair pathways in human cells will lead to novel therapeutic strategies to treat cancer and potentially other human diseases.
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Affiliation(s)
- Ryan B Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520-8040
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
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Asa ADDC, Wanotayan R, Sharma MK, Tsukada K, Shimada M, Matsumoto Y. Functional analysis of XRCC4 mutations in reported microcephaly and growth defect patients in terms of radiosensitivity. JOURNAL OF RADIATION RESEARCH 2021; 62:380-389. [PMID: 33842963 PMCID: PMC8127669 DOI: 10.1093/jrr/rrab016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/01/2021] [Indexed: 05/08/2023]
Abstract
Non-homologous end joining is one of the main pathways for DNA double-strand break (DSB) repair and is also implicated in V(D)J recombination in immune system. Therefore, mutations in non-homologous end-joining (NHEJ) proteins were found to be associated with immunodeficiency in human as well as in model animals. Several human patients with mutations in XRCC4 were reported to exhibit microcephaly and growth defects, but unexpectedly showed normal immune function. Here, to evaluate the functionality of these disease-associated mutations of XRCC4 in terms of radiosensitivity, we generated stable transfectants expressing these mutants in XRCC4-deficient murine M10 cells and measured their radiosensitivity by colony formation assay. V83_S105del, R225X and D254Mfs*68 were expressed at a similar level to wild-type XRCC4, while W43R, R161Q and R275X were expressed at even higher level than wild-type XRCC4. The expression levels of DNA ligase IV in the transfectants with these mutants were comparable to that in the wild-type XRCC4 transfectant. The V83S_S105del transfectant and, to a lesser extent, D254Mfs*68 transfectant, showed substantially increased radiosensitivity compared to the wild-type XRCC4 transfectant. The W43R, R161Q, R225X and R275X transfectants showed a slight but statistically significant increase in radiosensitivity compared to the wild-type XRCC4 transfectant. When expressed as fusion proteins with Green fluorescent protein (GFP), R225X, R275X and D254Mfs*68 localized to the cytoplasm, whereas other mutants localized to the nucleus. These results collectively indicated that the defects of XRCC4 in patients might be mainly due to insufficiency in protein quantity and impaired functionality, underscoring the importance of XRCC4's DSB repair function in normal development.
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Affiliation(s)
- Anie Day D C Asa
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Rujira Wanotayan
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
- Department of Radiological Technology, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Mukesh Kumar Sharma
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
- Department of Zoology, SPC Government College, Ajmer-305001, Rajasthan, India
| | - Kaima Tsukada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Mikio Shimada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Yoshihisa Matsumoto
- Corresponding author. Yoshihisa Matsumoto, Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan. E-mail: ; FAX: +81-3-5734-3703
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Chen S, Lee L, Naila T, Fishbain S, Wang A, Tomkinson AE, Lees-Miller SP, He Y. Structural basis of long-range to short-range synaptic transition in NHEJ. Nature 2021; 593:294-298. [PMID: 33854234 PMCID: PMC8122075 DOI: 10.1038/s41586-021-03458-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/15/2021] [Indexed: 02/07/2023]
Abstract
DNA double-strand breaks (DSBs) are a highly cytotoxic form of DNA damage and the incorrect repair of DSBs is linked to carcinogenesis1,2. The conserved error-prone non-homologous end joining (NHEJ) pathway has a key role in determining the effects of DSB-inducing agents that are used to treat cancer as well as the generation of the diversity in antibodies and T cell receptors2,3. Here we applied single-particle cryo-electron microscopy to visualize two key DNA-protein complexes that are formed by human NHEJ factors. The Ku70/80 heterodimer (Ku), the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs), DNA ligase IV (LigIV), XRCC4 and XLF form a long-range synaptic complex, in which the DNA ends are held approximately 115 Å apart. Two DNA end-bound subcomplexes comprising Ku and DNA-PKcs are linked by interactions between the DNA-PKcs subunits and a scaffold comprising LigIV, XRCC4, XLF, XRCC4 and LigIV. The relative orientation of the DNA-PKcs molecules suggests a mechanism for autophosphorylation in trans, which leads to the dissociation of DNA-PKcs and the transition into the short-range synaptic complex. Within this complex, the Ku-bound DNA ends are aligned for processing and ligation by the XLF-anchored scaffold, and a single catalytic domain of LigIV is stably associated with a nick between the two Ku molecules, which suggests that the joining of both strands of a DSB involves both LigIV molecules.
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Affiliation(s)
- Siyu Chen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, USA
| | - Linda Lee
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
- Robson DNA Science Centre, Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Tasmin Naila
- Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, NM, USA
- University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, USA
| | - Susan Fishbain
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Annie Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Alan E Tomkinson
- Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, NM, USA
- University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
- Robson DNA Science Centre, Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, USA.
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA.
- Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Northwestern University, Chicago, IL, USA.
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36
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Willaume S, Rass E, Fontanilla-Ramirez P, Moussa A, Wanschoor P, Bertrand P. A Link between Replicative Stress, Lamin Proteins, and Inflammation. Genes (Basel) 2021; 12:genes12040552. [PMID: 33918867 PMCID: PMC8070205 DOI: 10.3390/genes12040552] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/23/2021] [Accepted: 04/08/2021] [Indexed: 12/12/2022] Open
Abstract
Double-stranded breaks (DSB), the most toxic DNA lesions, are either a consequence of cellular metabolism, programmed as in during V(D)J recombination, or induced by anti-tumoral therapies or accidental genotoxic exposure. One origin of DSB sources is replicative stress, a major source of genome instability, especially when the integrity of the replication forks is not properly guaranteed. To complete stalled replication, restarting the fork requires complex molecular mechanisms, such as protection, remodeling, and processing. Recently, a link has been made between DNA damage accumulation and inflammation. Indeed, defects in DNA repair or in replication can lead to the release of DNA fragments in the cytosol. The recognition of this self-DNA by DNA sensors leads to the production of inflammatory factors. This beneficial response activating an innate immune response and destruction of cells bearing DNA damage may be considered as a novel part of DNA damage response. However, upon accumulation of DNA damage, a chronic inflammatory cellular microenvironment may lead to inflammatory pathologies, aging, and progression of tumor cells. Progress in understanding the molecular mechanisms of DNA damage repair, replication stress, and cytosolic DNA production would allow to propose new therapeutical strategies against cancer or inflammatory diseases associated with aging. In this review, we describe the mechanisms involved in DSB repair, the replicative stress management, and its consequences. We also focus on new emerging links between key components of the nuclear envelope, the lamins, and DNA repair, management of replicative stress, and inflammation.
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Stinson BM, Loparo JJ. Repair of DNA Double-Strand Breaks by the Nonhomologous End Joining Pathway. Annu Rev Biochem 2021; 90:137-164. [PMID: 33556282 DOI: 10.1146/annurev-biochem-080320-110356] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA double-strand breaks pose a serious threat to genome stability. In vertebrates, these breaks are predominantly repaired by nonhomologous end joining (NHEJ), which pairs DNA ends in a multiprotein synaptic complex to promote their direct ligation. NHEJ is a highly versatile pathway that uses an array of processing enzymes to modify damaged DNA ends and enable their ligation. The mechanisms of end synapsis and end processing have important implications for genome stability. Rapid and stable synapsis is necessary to limit chromosome translocations that result from the mispairing of DNA ends. Furthermore, end processing must be tightly regulated to minimize mutations at the break site. Here, we review our current mechanistic understanding of vertebrate NHEJ, with a particular focus on end synapsis and processing.
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Affiliation(s)
- Benjamin M Stinson
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
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Carney SM, Moreno AT, Piatt SC, Cisneros-Aguirre M, Lopezcolorado FW, Stark JM, Loparo JJ. XLF acts as a flexible connector during non-homologous end joining. eLife 2020; 9:e61920. [PMID: 33289484 PMCID: PMC7744095 DOI: 10.7554/elife.61920] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 12/07/2020] [Indexed: 01/01/2023] Open
Abstract
Non-homologous end joining (NHEJ) is the predominant pathway that repairs DNA double-strand breaks in vertebrates. During NHEJ DNA ends are held together by a multi-protein synaptic complex until they are ligated. Here, we use Xenopus laevis egg extract to investigate the role of the intrinsically disordered C-terminal tail of the XRCC4-like factor (XLF), a critical factor in end synapsis. We demonstrate that the XLF tail along with the Ku-binding motif (KBM) at the extreme C-terminus are required for end joining. Although the underlying sequence of the tail can be varied, a minimal tail length is required for NHEJ. Single-molecule FRET experiments that observe end synapsis in real-time show that this defect is due to a failure to closely align DNA ends. Our data supports a model in which a single C-terminal tail tethers XLF to Ku, while allowing XLF to form interactions with XRCC4 that enable synaptic complex formation.
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Affiliation(s)
- Sean M Carney
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
| | - Andrew T Moreno
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
| | - Sadie C Piatt
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
- Harvard Graduate Program in Biophysics, Harvard Medical SchoolBostonUnited States
| | - Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of HopeDuarteUnited States
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of HopeDuarteUnited States
| | | | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of HopeDuarteUnited States
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of HopeDuarteUnited States
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
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39
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Mastio J, Saeed MB, Wurzer H, Krecke M, Westerberg LS, Thomas C. Higher Incidence of B Cell Malignancies in Primary Immunodeficiencies: A Combination of Intrinsic Genomic Instability and Exocytosis Defects at the Immunological Synapse. Front Immunol 2020; 11:581119. [PMID: 33240268 PMCID: PMC7680899 DOI: 10.3389/fimmu.2020.581119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/09/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital defects of the immune system called primary immunodeficiency disorders (PID) describe a group of diseases characterized by a decrease, an absence, or a malfunction of at least one part of the immune system. As a result, PID patients are more prone to develop life-threatening complications, including cancer. PID currently include over 400 different disorders, however, the variety of PID-related cancers is narrow. We discuss here reasons for this clinical phenotype. Namely, PID can lead to cell intrinsic failure to control cell transformation, failure to activate tumor surveillance by cytotoxic cells or both. As the most frequent tumors seen among PID patients stem from faulty lymphocyte development leading to leukemia and lymphoma, we focus on the extensive genomic alterations needed to create the vast diversity of B and T lymphocytes with potential to recognize any pathogen and why defects in these processes lead to malignancies in the immunodeficient environment of PID patients. In the second part of the review, we discuss PID affecting tumor surveillance and especially membrane trafficking defects caused by altered exocytosis and regulation of the actin cytoskeleton. As an impairment of these membrane trafficking pathways often results in dysfunctional effector immune cells, tumor cell immune evasion is elevated in PID. By considering new anti-cancer treatment concepts, such as transfer of genetically engineered immune cells, restoration of anti-tumor immunity in PID patients could be an approach to complement standard therapies.
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Affiliation(s)
- Jérôme Mastio
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Mezida B Saeed
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Hannah Wurzer
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Max Krecke
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Lisa S Westerberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Clément Thomas
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
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40
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Dimers of DNA-PK create a stage for DNA double-strand break repair. Nat Struct Mol Biol 2020; 28:13-19. [DOI: 10.1038/s41594-020-00517-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/08/2020] [Indexed: 11/08/2022]
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41
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Structural biology of multicomponent assemblies in DNA double-strand-break repair through non-homologous end joining. Curr Opin Struct Biol 2020; 61:9-16. [DOI: 10.1016/j.sbi.2019.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/30/2019] [Indexed: 01/19/2023]
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42
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Structural mechanism of DNA-end synapsis in the non-homologous end joining pathway for repairing double-strand breaks: bridge over troubled ends. Biochem Soc Trans 2020; 47:1609-1619. [PMID: 31829407 DOI: 10.1042/bst20180518] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/18/2022]
Abstract
Non-homologous end joining (NHEJ) is a major repair pathway for DNA double-strand breaks (DSBs), which is the most toxic DNA damage in cells. Unrepaired DSBs can cause genome instability, tumorigenesis or cell death. DNA end synapsis is the first and probably the most important step of the NHEJ pathway, aiming to bring two broken DNA ends close together and provide structural stability for end processing and ligation. This process is mediated through a group of NHEJ proteins forming higher-order complexes, to recognise and bridge two DNA ends. Spatial and temporal understanding of the structural mechanism of DNA-end synapsis has been largely advanced through recent structural and single-molecule studies of NHEJ proteins. This review focuses on core NHEJ proteins that mediate DNA end synapsis through their unique structures and interaction properties, as well as how they play roles as anchor and linker proteins during the process of 'bridge over troubled ends'.
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43
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Kim K, Min J, Kirby TW, Gabel SA, Pedersen LC, London RE. Ligand binding characteristics of the Ku80 von Willebrand domain. DNA Repair (Amst) 2020; 85:102739. [PMID: 31733588 PMCID: PMC7495496 DOI: 10.1016/j.dnarep.2019.102739] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/18/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022]
Abstract
The N-terminal von Willebrand domain of Ku80 supports interactions with a Ku binding motif (KBM) that has been identified in at least three other DNA repair proteins: the non-homologous end joining (NHEJ) scaffold APLF, the modulator of retrovirus infection, MRI, and the Werner syndrome protein (WRN). A second, more recently identified Ku binding motif present in XLF and several other proteins (KBMX) has also been reported to interact with this domain. The isolated Ku80 von Willebrand antigen domain (vWA) from Xenopus laevis has a sequence that is 60% identical with the human domain, is readily expressed and has been used to investigate these interactions. Structural characterization of the complexes formed with the KBM motifs in human APLF, MRI, and WRN identify a conserved binding site that is consistent with previously-reported mutational studies. In contrast with the KBM binding site, structural studies indicate that the KBMX site is occluded by a distorted helix. Fluorescence polarization and 19F NMR studies of a fluorinated XLF C-terminal peptide failed to indicate any interaction with the frog vWA. It was hypothesized that availability of this binding site is conditional, i.e., dependent on specific experimental conditions or other repair factors to make the site available for binding. Modulating the fraction of KBMX-accessible binding site mutationally demonstrated that the more open site is capable of binding the KBMXXLF motif peptide. It is suggested that the conditional nature of KBMX binding limits formation of non-productive complexes so that activation-dependent site availability can more optimally support advancing the synapsis process.
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Affiliation(s)
- Kyungmin Kim
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Jungki Min
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Thomas W Kirby
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Scott A Gabel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA.
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Bétermier M, Borde V, de Villartay JP. Coupling DNA Damage and Repair: an Essential Safeguard during Programmed DNA Double-Strand Breaks? Trends Cell Biol 2019; 30:87-96. [PMID: 31818700 DOI: 10.1016/j.tcb.2019.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/15/2019] [Accepted: 11/18/2019] [Indexed: 12/31/2022]
Abstract
DNA double-strand breaks (DSBs) are the most toxic DNA lesions given their oncogenic potential. Nevertheless, programmed DSBs (prDSBs) contribute to several biological processes. Formation of prDSBs is the 'price to pay' to achieve these essential biological functions. Generated by domesticated PiggyBac transposases, prDSBs have been integrated in the life cycle of ciliates. Created by Spo11 during meiotic recombination, they constitute a driving force of evolution and ensure balanced chromosome content for successful reproduction. Produced by the RAG1/2 recombinase, they are required for the development of the adaptive immune system in many species. The coevolution of processes that couple introduction of prDSBs to their accurate repair may constitute an effective safeguard against genomic instability.
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Affiliation(s)
- Mireille Bétermier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
| | - Valérie Borde
- Institut Curie, CNRS UMR3244, Sorbonne Université, Paris, France.
| | - Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, INSERM UMR1163, Université Paris Descartes Sorbonne Paris Cité, Institut Imagine, Paris, France.
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45
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Ruis B, Molan A, Takasugi T, Hendrickson EA. Absence of XRCC4 and its paralogs in human cells reveal differences in outcomes for DNA repair and V(D)J recombination. DNA Repair (Amst) 2019; 85:102738. [PMID: 31731258 DOI: 10.1016/j.dnarep.2019.102738] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 02/06/2023]
Abstract
The repair of DNA double-stranded breaks (DSBs) is an essential function performed by the Classical Non-Homologous End-Joining (C-NHEJ) pathway in higher eukaryotes. C-NHEJ, in fact, does double duty as it is also required for the repair of the intermediates formed during lymphoid B- and T-cell recombination. Consequently, the failure to properly repair DSBs leads to both genomic instability and immunodeficiency. A critical DSB protein required for C-NHEJ is the DNA Ligase IV (LIGIV) accessory factor, X-Ray Cross Complementing 4 (XRCC4). XRCC4 is believed to stabilize LIGIV, participate in LIGIV activation, and to help tether the broken DSB ends together. XRCC4's role in these processes has been muddied by the identification of two additional XRCC4 paralogs, XRCC4-Like Factor (XLF), and Paralog of XRCC4 and XLF (PAXX). The roles that these paralogs play in C-NHEJ is partially understood, but, in turn, has itself been obscured by species-specific differences observed in the absence of one or the other paralogs. In order to investigate the role(s) that XRCC4 may play, with or without XLF and/or PAXX, in lymphoid variable(diversity)joining [V(D)J] recombination as well as in DNA DSB repair in human somatic cells, we utilized gene targeting to inactivate the XRCC4 gene in both parental and XLF- HCT116 cells and then inactivated PAXX in those same cell lines. The loss of XRCC4 expression by itself led, as anticipated, to increased sensitivity to DNA damaging agents as well as an increased dependence on microhomology-mediated DNA repair whether in the context of DSB repair or during V(D)J recombination. The additional loss of XLF in these cell lines sensitized the cells even more whereas the presence or absence of PAXX was scarcely negligible. These studies demonstrate that, of the three LIG4 accessory factor paralogs, the absence of XRCC4 influences DNA repair and recombination the most in human cells.
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Affiliation(s)
- Brian Ruis
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN, 55455, United States
| | - Amy Molan
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN, 55455, United States
| | - Taylor Takasugi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN, 55455, United States
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN, 55455, United States.
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46
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The essential elements for the noncovalent association of two DNA ends during NHEJ synapsis. Nat Commun 2019; 10:3588. [PMID: 31399561 PMCID: PMC6688983 DOI: 10.1038/s41467-019-11507-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/17/2019] [Indexed: 01/13/2023] Open
Abstract
One of the most central questions about the repair of a double-strand DNA break (DSB) concerns how the two free DNA ends are brought together - a step called synapsis. Using single-molecule FRET (smFRET), we show here that both Ku plus XRCC4:DNA ligase IV are necessary and sufficient to achieve a flexible synapsis of blunt DNA ends, whereas either alone is not. Addition of XLF causes a transition to a close synaptic state, and maximum efficiency of close synapsis is achieved within 20 min. The promotion of close synapsis by XLF indicates a role that is independent of a filament structure, with action focused at the very ends of each duplex. DNA-PKcs is not required for the formation of either the flexible or close synaptic states. This model explains in biochemical terms the evolutionarily central synaptic role of Ku, X4L4, and XLF in NHEJ for all eukaryotes.
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47
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Xue R, Peng Y, Han B, Li X, Chen Y, Pei H. Metastasis suppressor NME1 promotes non-homologous end joining of DNA double-strand breaks. DNA Repair (Amst) 2019; 77:27-35. [DOI: 10.1016/j.dnarep.2019.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 03/03/2019] [Accepted: 03/03/2019] [Indexed: 10/27/2022]
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48
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Plugged into the Ku-DNA hub: The NHEJ network. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:62-76. [PMID: 30851288 DOI: 10.1016/j.pbiomolbio.2019.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 12/16/2022]
Abstract
In vertebrates, double-strand breaks in DNA are primarily repaired by Non-Homologous End-Joining (NHEJ). The ring-shaped Ku heterodimer rapidly senses and threads onto broken DNA ends forming a recruiting hub. Through protein-protein contacts eventually reinforced by protein-DNA interactions, the Ku-DNA hub attracts a series of specialized proteins with scaffolding and/or enzymatic properties. To shed light on these dynamic interplays, we review here current knowledge on proteins directly interacting with Ku and on the contact points involved, with a particular accent on the different classes of Ku-binding motifs identified in several Ku partners. An integrated structural model of the core NHEJ network at the synapsis step is proposed.
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49
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Yeap LS, Meng FL. Cis- and trans-factors affecting AID targeting and mutagenic outcomes in antibody diversification. Adv Immunol 2019; 141:51-103. [PMID: 30904133 DOI: 10.1016/bs.ai.2019.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antigen receptor diversification is a hallmark of adaptive immunity which allows specificity of the receptor to particular antigen. B cell receptor (BCR) or its secreted form, antibody, is diversified through antigen-independent and antigen-dependent mechanisms. During B cell development in bone marrow, BCR is diversified via V(D)J recombination mediated by RAG endonuclease. Upon stimulation by antigen, B cell undergo somatic hypermutation (SHM) to allow affinity maturation and class switch recombination (CSR) to change the effector function of the antibody. Both SHM and CSR are initiated by activation-induced cytidine deaminase (AID). Repair of AID-initiated lesions through different DNA repair pathways results in diverse mutagenic outcomes. Here, we focus on discussing cis- and trans-factors that target AID to its substrates and factors that affect different outcomes of AID-initiated lesions. The knowledge of mechanisms that govern AID targeting and outcomes could be harnessed to elicit rare functional antibodies and develop ex vivo antibody diversification approaches with diversifying base editors.
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Affiliation(s)
- Leng-Siew Yeap
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Fei-Long Meng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
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Liu M, Rehman S, Tang X, Gu K, Fan Q, Chen D, Ma W. Methodologies for Improving HDR Efficiency. Front Genet 2019; 9:691. [PMID: 30687381 PMCID: PMC6338032 DOI: 10.3389/fgene.2018.00691] [Citation(s) in RCA: 186] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/11/2018] [Indexed: 12/26/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is a precise genome manipulating technology that can be programmed to induce double-strand break (DSB) in the genome wherever needed. After nuclease cleavage, DSBs can be repaired by non-homologous end joining (NHEJ) or homology-directed repair (HDR) pathway. For producing targeted gene knock-in or other specific mutations, DSBs should be repaired by the HDR pathway. While NHEJ can cause various length insertions/deletion mutations (indels), which can lead the targeted gene to lose its function by shifting the open reading frame (ORF). Furthermore, HDR has low efficiency compared with the NHEJ pathway. In order to modify the gene precisely, numerous methods arose by inhibiting NHEJ or enhancing HDR, such as chemical modulation, synchronized expression, and overlapping homology arm. Here we focus on the efficiency and other considerations of these methodologies.
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Affiliation(s)
- Mingjie Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Saad Rehman
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Xidian Tang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Kui Gu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Qinlei Fan
- China Animal Health and Epidemiology Center, Qingdao, China
| | - Dekun Chen
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Wentao Ma
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
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