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Gnugnoli M, Rinaldi C, Casari E, Pizzul P, Bonetti D, Longhese MP. Proteasome-mediated degradation of long-range nucleases negatively regulates resection of DNA double-strand breaks. iScience 2024; 27:110373. [PMID: 39071887 PMCID: PMC11277358 DOI: 10.1016/j.isci.2024.110373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/30/2024] [Accepted: 06/21/2024] [Indexed: 07/30/2024] Open
Abstract
Homologous recombination is initiated by the nucleolytic degradation (resection) of DNA double-strand breaks (DSBs). DSB resection is a two-step process. In the short-range step, the MRX (Mre11-Rad50-Xrs2) complex, together with Sae2, incises the 5'-terminated strand at the DSB end and resects back toward the DNA end. Then, the long-range resection nucleases Exo1 and Dna2 further elongate the resected DNA tracts. We found that mutations lowering proteasome functionality bypass the need for Sae2 in DSB resection. In particular, the dysfunction of the proteasome subunit Rpn11 leads to hyper-resection and increases the levels of both Exo1 and Dna2 to such an extent that it allows the bypass of the requirement for either Exo1 or Dna2, but not for both. These observations, along with the finding that Exo1 and Dna2 are ubiquitylated, indicate a role of the proteasome in restraining DSB resection by negatively controlling the abundance of the long-range resection nucleases.
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Affiliation(s)
- Marco Gnugnoli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Diego Bonetti
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
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2
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Peng L, Lidan H, Cuicui Z, Zhe Z, Sen Y, Xuan W, Ganghua L, Chao Z, Zhensheng L, Qiming W. DNA double-strand break repair capacity and its pathway gene variants predict the risk and prognosis of lung cancer. Lung Cancer 2024; 192:107831. [PMID: 38805902 DOI: 10.1016/j.lungcan.2024.107831] [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: 03/23/2024] [Revised: 05/19/2024] [Accepted: 05/23/2024] [Indexed: 05/30/2024]
Abstract
OBJECTIVES This study aims to investigate the association between DNA double-strand breaks (DSBs) repair capacity, variations in DSBs-related genes, and the occurrence and prognosis of lung cancer in the Chinese population. METHODS Peripheral blood mononuclear cells (PBMC) were collected from 98 lung cancer patients and 60 healthy individuals. The individual DSBs repair capacity was assessed by measuring changes in γ-H2AX levels after treatment with etoposide. Exonic sequencing of 45 DSBs-related genes was performed on PBMC DNA. Logistic regression analysis was conducted to examine the relationship between lung cancer risk and DSBs repair capacity as well as germlines gene variations. Survival analysis employed the Cox proportional hazards regression model, Kaplan-Meier method, and Log-rank test. RESULTS Lower DSBs repair capacity predicted an increased risk of developing lung cancer (OR = 0.94, 95 %CI = 0.917-0.964, P<0.001). Among lung cancer patients, higher DSBs repair capacity was associated with shorter progression-free survival (PFS) during first-line treatment (HR = 1.80, 95 %CI = 1.10-3.00, P = 0.031). Patients with BRCA1 mutations had shorter overall survival (OS) (HR = 1.92, 95 %CI = 1.12-3.28, P = 0.018). Patients with FOXO3 mutations had shorter PFS (HR = 4.23, 95 %CI = 1.44-12.36, P = 0.009). Analysis of patients treated with immune checkpoint inhibitors (ICIs) indicated that LIG4 mutations were associated with shorter PFS (HR = 2.90, 95 %CI = 1.00-8.10, P = 0.041). CONCLUSIONS This study concludes that assessing DSBs repair capacity holds promise for predicting both lung cancer risk and prognosis in the Chinese population. Further large-scale studies and functional validation of specific gene mutations related to double-strand breaks are necessary for confirmation.
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Affiliation(s)
- Li Peng
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China; Institute of Cancer Research, Henan Academy of Innovations in Medical Science, Zhengzhou 450008, China
| | - Hao Lidan
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China
| | - Zhang Cuicui
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China; Institute of Cancer Research, Henan Academy of Innovations in Medical Science, Zhengzhou 450008, China
| | - Zhang Zhe
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China; Institute of Cancer Research, Henan Academy of Innovations in Medical Science, Zhengzhou 450008, China
| | - Yang Sen
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China; Institute of Cancer Research, Henan Academy of Innovations in Medical Science, Zhengzhou 450008, China
| | - Wu Xuan
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China
| | - Li Ganghua
- Geneplus-Shenzhen, Shenzhen 518000, China
| | - Zhang Chao
- Geneplus-Shenzhen, Shenzhen 518000, China
| | - Liu Zhensheng
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China
| | - Wang Qiming
- Department of Internal Medicine, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou 450008, China; Institute of Cancer Research, Henan Academy of Innovations in Medical Science, Zhengzhou 450008, China.
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3
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Galanti L, Peritore M, Gnügge R, Cannavo E, Heipke J, Palumbieri MD, Steigenberger B, Symington LS, Cejka P, Pfander B. Dbf4-dependent kinase promotes cell cycle controlled resection of DNA double-strand breaks and repair by homologous recombination. Nat Commun 2024; 15:2890. [PMID: 38570537 PMCID: PMC10991553 DOI: 10.1038/s41467-024-46951-z] [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: 07/19/2023] [Accepted: 03/13/2024] [Indexed: 04/05/2024] Open
Abstract
DNA double-strand breaks (DSBs) can be repaired by several pathways. In eukaryotes, DSB repair pathway choice occurs at the level of DNA end resection and is controlled by the cell cycle. Upon cell cycle-dependent activation, cyclin-dependent kinases (CDKs) phosphorylate resection proteins and thereby stimulate end resection and repair by homologous recombination (HR). However, inability of CDK phospho-mimetic mutants to bypass this cell cycle regulation, suggests that additional cell cycle regulators may be important. Here, we identify Dbf4-dependent kinase (DDK) as a second major cell cycle regulator of DNA end resection. Using inducible genetic and chemical inhibition of DDK in budding yeast and human cells, we show that end resection and HR require activation by DDK. Mechanistically, DDK phosphorylates at least two resection nucleases in budding yeast: the Mre11 activator Sae2, which promotes resection initiation, as well as the Dna2 nuclease, which promotes resection elongation. Notably, synthetic activation of DDK allows limited resection and HR in G1 cells, suggesting that DDK is a key component of DSB repair pathway selection.
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Affiliation(s)
- Lorenzo Galanti
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
| | - Martina Peritore
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK
| | - Robert Gnügge
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Elda Cannavo
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Bellinzona, Switzerland
| | - Johannes Heipke
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
| | - Maria Dilia Palumbieri
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
- Research Group of Proteomics and ADP-Ribosylation Signaling, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Barbara Steigenberger
- Mass Spectrometry Core Facility, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Boris Pfander
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany.
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany.
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4
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Myler LR, Toia B, Vaughan CK, Takai K, Matei AM, Wu P, Paull TT, de Lange T, Lottersberger F. DNA-PK and the TRF2 iDDR inhibit MRN-initiated resection at leading-end telomeres. Nat Struct Mol Biol 2023; 30:1346-1356. [PMID: 37653239 PMCID: PMC10497418 DOI: 10.1038/s41594-023-01072-x] [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] [Received: 01/18/2023] [Accepted: 07/18/2023] [Indexed: 09/02/2023]
Abstract
Telomeres replicated by leading-strand synthesis lack the 3' overhang required for telomere protection. Surprisingly, resection of these blunt telomeres is initiated by the telomere-specific 5' exonuclease Apollo rather than the Mre11-Rad50-Nbs1 (MRN) complex, the nuclease that acts at DNA breaks. Without Apollo, leading-end telomeres undergo fusion, which, as demonstrated here, is mediated by alternative end joining. Here, we show that DNA-PK and TRF2 coordinate the repression of MRN at blunt mouse telomeres. DNA-PK represses an MRN-dependent long-range resection, while the endonuclease activity of MRN-CtIP, which could cleave DNA-PK off of blunt telomere ends, is inhibited in vitro and in vivo by the iDDR of TRF2. AlphaFold-Multimer predicts a conserved association of the iDDR with Rad50, potentially interfering with CtIP binding and MRN endonuclease activation. We propose that repression of MRN-mediated resection is a conserved aspect of telomere maintenance and represents an ancient feature of DNA-PK and the iDDR.
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Affiliation(s)
- Logan R Myler
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Cara K Vaughan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Kaori Takai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Andreea M Matei
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Peng Wu
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA.
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden.
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5
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Laufer VA, Glover TW, Wilson TE. Applications of advanced technologies for detecting genomic structural variation. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108475. [PMID: 37931775 PMCID: PMC10792551 DOI: 10.1016/j.mrrev.2023.108475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/07/2023] [Accepted: 11/02/2023] [Indexed: 11/08/2023]
Abstract
Chromosomal structural variation (SV) encompasses a heterogenous class of genetic variants that exerts strong influences on human health and disease. Despite their importance, many structural variants (SVs) have remained poorly characterized at even a basic level, a discrepancy predicated upon the technical limitations of prior genomic assays. However, recent advances in genomic technology can identify and localize SVs accurately, opening new questions regarding SV risk factors and their impacts in humans. Here, we first define and classify human SVs and their generative mechanisms, highlighting characteristics leveraged by various SV assays. We next examine the first-ever gapless assembly of the human genome and the technical process of assembling it, which required third-generation sequencing technologies to resolve structurally complex loci. The new portions of that "telomere-to-telomere" and subsequent pangenome assemblies highlight aspects of SV biology likely to develop in the near-term. We consider the strengths and limitations of the most promising new SV technologies and when they or longstanding approaches are best suited to meeting salient goals in the study of human SV in population-scale genomics research, clinical, and public health contexts. It is a watershed time in our understanding of human SV when new approaches are expected to fundamentally change genomic applications.
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Affiliation(s)
- Vincent A Laufer
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas W Glover
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas E Wilson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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6
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Rinaldi C, Pizzul P, Casari E, Mangiagalli M, Tisi R, Longhese MP. The Ku complex promotes DNA end-bridging and this function is antagonized by Tel1/ATM kinase. Nucleic Acids Res 2023; 51:1783-1802. [PMID: 36762474 PMCID: PMC9976877 DOI: 10.1093/nar/gkad062] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 02/11/2023] Open
Abstract
DNA double-strand breaks (DSBs) can be repaired by either homologous recombination (HR) or non-homologous end-joining (NHEJ). NHEJ is induced by the binding to DSBs of the Ku70-Ku80 heterodimer, which acts as a hub for the recruitment of downstream NHEJ components. An important issue in DSB repair is the maintenance of the DSB ends in close proximity, a function that in yeast involves the MRX complex and Sae2. Here, we provide evidence that Ku contributes to keep the DNA ends tethered to each other. The ku70-C85Y mutation, which increases Ku affinity for DNA and its persistence very close to the DSB ends, enhances DSB end-tethering and suppresses the end-tethering defect of sae2Δ cells. Impairing histone removal around DSBs either by eliminating Tel1 kinase activity or nucleosome remodelers enhances Ku persistence at DSBs and DSB bridging, suggesting that Tel1 antagonizes the Ku function in supporting end-tethering by promoting nucleosome removal and possibly Ku sliding inwards. As Ku provides a block to DSB resection, this Tel1 function can be important to regulate the mode by which DSBs are repaired.
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Affiliation(s)
- Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Marco Mangiagalli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Renata Tisi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
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7
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Frigerio C, Di Nisio E, Galli M, Colombo CV, Negri R, Clerici M. The Chromatin Landscape around DNA Double-Strand Breaks in Yeast and Its Influence on DNA Repair Pathway Choice. Int J Mol Sci 2023; 24:ijms24043248. [PMID: 36834658 PMCID: PMC9967470 DOI: 10.3390/ijms24043248] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/21/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
DNA double-strand breaks (DSBs) are harmful DNA lesions, which elicit catastrophic consequences for genome stability if not properly repaired. DSBs can be repaired by either non-homologous end joining (NHEJ) or homologous recombination (HR). The choice between these two pathways depends on which proteins bind to the DSB ends and how their action is regulated. NHEJ initiates with the binding of the Ku complex to the DNA ends, while HR is initiated by the nucleolytic degradation of the 5'-ended DNA strands, which requires several DNA nucleases/helicases and generates single-stranded DNA overhangs. DSB repair occurs within a precisely organized chromatin environment, where the DNA is wrapped around histone octamers to form the nucleosomes. Nucleosomes impose a barrier to the DNA end processing and repair machinery. Chromatin organization around a DSB is modified to allow proper DSB repair either by the removal of entire nucleosomes, thanks to the action of chromatin remodeling factors, or by post-translational modifications of histones, thus increasing chromatin flexibility and the accessibility of repair enzymes to the DNA. Here, we review histone post-translational modifications occurring around a DSB in the yeast Saccharomyces cerevisiae and their role in DSB repair, with particular attention to DSB repair pathway choice.
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Affiliation(s)
- Chiara Frigerio
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Elena Di Nisio
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy
| | - Michela Galli
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Chiara Vittoria Colombo
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Rodolfo Negri
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy, 00185 Rome, Italy
- Correspondence: (R.N.); (M.C.)
| | - Michela Clerici
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
- Correspondence: (R.N.); (M.C.)
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8
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Lascarez-Lagunas LI, Martinez-Garcia M, Nadarajan S, Diaz-Pacheco BN, Berson E, Colaiácovo MP. Chromatin landscape, DSB levels, and cKU-70/80 contribute to patterning of meiotic DSB processing along chromosomes in C. elegans. PLoS Genet 2023; 19:e1010627. [PMID: 36706157 PMCID: PMC9907818 DOI: 10.1371/journal.pgen.1010627] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/08/2023] [Accepted: 01/20/2023] [Indexed: 01/28/2023] Open
Abstract
Programmed DNA double-strand break (DSB) formation is essential for achieving accurate chromosome segregation during meiosis. DSB repair timing and template choice are tightly regulated. However, little is known about how DSB distribution and the choice of repair pathway are regulated along the length of chromosomes, which has direct effects on the recombination landscape and chromosome remodeling at late prophase I. Here, we use the spatiotemporal resolution of meiosis in the Caenorhabditis elegans germline along with genetic approaches to study distribution of DSB processing and its regulation. High-resolution imaging of computationally straightened chromosomes immunostained for the RAD-51 recombinase marking DSB repair sites reveals that the pattern of RAD-51 foci throughout pachytene resembles crossover distribution in wild type. Specifically, RAD-51 foci occur primarily along the gene-poor distal thirds of the chromosomes in both early and late pachytene, and on both the X and the autosomes. However, this biased off-center distribution can be abrogated by the formation of excess DSBs. Reduced condensin function, but not an increase in total physical axial length, results in a homogeneous distribution of RAD-51 foci, whereas regulation of H3K9 methylation is required for the enrichment of RAD-51 at off-center positions. Finally, the DSB recognition heterodimer cKU-70/80, but not the non-homologous end-joining canonical ligase LIG-4, contributes to the enriched off-center distribution of RAD-51 foci. Taken together, our data supports a model by which regulation of the chromatin landscape, DSB levels, and DSB detection by cKU-70/80 collaborate to promote DSB processing by homologous recombination at off-center regions of the chromosomes in C. elegans.
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Affiliation(s)
- Laura I. Lascarez-Lagunas
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marina Martinez-Garcia
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Saravanapriah Nadarajan
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brianna N. Diaz-Pacheco
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Elizaveta Berson
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mónica P. Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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9
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Yam CQX, Lim HH, Surana U. DNA damage checkpoint execution and the rules of its disengagement. Front Cell Dev Biol 2022; 10:1020643. [PMID: 36274841 PMCID: PMC9582513 DOI: 10.3389/fcell.2022.1020643] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chromosomes are susceptible to damage during their duplication and segregation or when exposed to genotoxic stresses. Left uncorrected, these lesions can result in genomic instability, leading to cells' diminished fitness, unbridled proliferation or death. To prevent such fates, checkpoint controls transiently halt cell cycle progression to allow time for the implementation of corrective measures. Prominent among these is the DNA damage checkpoint which operates at G2/M transition to ensure that cells with damaged chromosomes do not enter the mitotic phase. The execution and maintenance of cell cycle arrest are essential aspects of G2/M checkpoint and have been studied in detail. Equally critical is cells' ability to switch-off the checkpoint controls after a successful completion of corrective actions and to recommence cell cycle progression. Interestingly, when corrective measures fail, cells can mount an unusual cellular response, termed adaptation, where they escape checkpoint arrest and resume cell cycle progression with damaged chromosomes at the cost of genome instability or even death. Here, we discuss the DNA damage checkpoint, the mitotic networks it inhibits to prevent segregation of damaged chromosomes and the strategies cells employ to quench the checkpoint controls to override the G2/M arrest.
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Affiliation(s)
| | - Hong Hwa Lim
- A*STAR Singapore Immunology Network, Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Uttam Surana
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
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10
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Vanderwaeren L, Dok R, Voordeckers K, Nuyts S, Verstrepen KJ. Saccharomyces cerevisiae as a Model System for Eukaryotic Cell Biology, from Cell Cycle Control to DNA Damage Response. Int J Mol Sci 2022; 23:11665. [PMID: 36232965 PMCID: PMC9570374 DOI: 10.3390/ijms231911665] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022] Open
Abstract
The yeast Saccharomyces cerevisiae has been used for bread making and beer brewing for thousands of years. In addition, its ease of manipulation, well-annotated genome, expansive molecular toolbox, and its strong conservation of basic eukaryotic biology also make it a prime model for eukaryotic cell biology and genetics. In this review, we discuss the characteristics that made yeast such an extensively used model organism and specifically focus on the DNA damage response pathway as a prime example of how research in S. cerevisiae helped elucidate a highly conserved biological process. In addition, we also highlight differences in the DNA damage response of S. cerevisiae and humans and discuss the challenges of using S. cerevisiae as a model system.
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Affiliation(s)
- Laura Vanderwaeren
- Laboratory of Experimental Radiotherapy, Department of Oncology, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Genetics and Genomics, Centre for Microbial and Plant Genetics, Department M2S, KU Leuven, 3001 Leuven, Belgium
- Laboratory for Systems Biology, VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium
| | - Rüveyda Dok
- Laboratory of Experimental Radiotherapy, Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Karin Voordeckers
- Laboratory of Genetics and Genomics, Centre for Microbial and Plant Genetics, Department M2S, KU Leuven, 3001 Leuven, Belgium
- Laboratory for Systems Biology, VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium
| | - Sandra Nuyts
- Laboratory of Experimental Radiotherapy, Department of Oncology, KU Leuven, 3000 Leuven, Belgium
- Department of Radiation Oncology, Leuven Cancer Institute, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Kevin J. Verstrepen
- Laboratory of Genetics and Genomics, Centre for Microbial and Plant Genetics, Department M2S, KU Leuven, 3001 Leuven, Belgium
- Laboratory for Systems Biology, VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium
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11
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Pizzul P, Casari E, Gnugnoli M, Rinaldi C, Corallo F, Longhese MP. The DNA damage checkpoint: A tale from budding yeast. Front Genet 2022; 13:995163. [PMID: 36186482 PMCID: PMC9520983 DOI: 10.3389/fgene.2022.995163] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022] Open
Abstract
Studies performed in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have led the way in defining the DNA damage checkpoint and in identifying most of the proteins involved in this regulatory network, which turned out to have structural and functional equivalents in humans. Subsequent experiments revealed that the checkpoint is an elaborate signal transduction pathway that has the ability to sense and signal the presence of damaged DNA and transduce this information to influence a multifaceted cellular response that is essential for cancer avoidance. This review focuses on the work that was done in Saccharomyces cerevisiae to articulate the checkpoint concept, to identify its players and the mechanisms of activation and deactivation.
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12
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Maksoud S. The DNA Double-Strand Break Repair in Glioma: Molecular Players and Therapeutic Strategies. Mol Neurobiol 2022; 59:5326-5365. [PMID: 35696013 DOI: 10.1007/s12035-022-02915-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 06/05/2022] [Indexed: 12/12/2022]
Abstract
Gliomas are the most frequent type of tumor in the central nervous system, which exhibit properties that make their treatment difficult, such as cellular infiltration, heterogeneity, and the presence of stem-like cells responsible for tumor recurrence. The response of this type of tumor to chemoradiotherapy is poor, possibly due to a higher repair activity of the genetic material, among other causes. The DNA double-strand breaks are an important type of lesion to the genetic material, which have the potential to trigger processes of cell death or cause gene aberrations that could promote tumorigenesis. This review describes how the different cellular elements regulate the formation of DNA double-strand breaks and their repair in gliomas, discussing the therapeutic potential of the induction of this type of lesion and the suppression of its repair as a control mechanism of brain tumorigenesis.
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Affiliation(s)
- Semer Maksoud
- Experimental Therapeutics and Molecular Imaging Unit, Department of Neurology, Neuro-Oncology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
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13
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Fowler FC, Chen BR, Zolnerowich N, Wu W, Pavani R, Paiano J, Peart C, Chen Z, Nussenzweig A, Sleckman BP, Tyler JK. DNA-PK promotes DNA end resection at DNA double strand breaks in G 0 cells. eLife 2022; 11:74700. [PMID: 35575473 PMCID: PMC9122494 DOI: 10.7554/elife.74700] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 05/06/2022] [Indexed: 11/16/2022] Open
Abstract
DNA double-strand break (DSB) repair by homologous recombination is confined to the S and G2 phases of the cell cycle partly due to 53BP1 antagonizing DNA end resection in G1 phase and non-cycling quiescent (G0) cells where DSBs are predominately repaired by non-homologous end joining (NHEJ). Unexpectedly, we uncovered extensive MRE11- and CtIP-dependent DNA end resection at DSBs in G0 murine and human cells. A whole genome CRISPR/Cas9 screen revealed the DNA-dependent kinase (DNA-PK) complex as a key factor in promoting DNA end resection in G0 cells. In agreement, depletion of FBXL12, which promotes ubiquitylation and removal of the KU70/KU80 subunits of DNA-PK from DSBs, promotes even more extensive resection in G0 cells. In contrast, a requirement for DNA-PK in promoting DNA end resection in proliferating cells at the G1 or G2 phase of the cell cycle was not observed. Our findings establish that DNA-PK uniquely promotes DNA end resection in G0, but not in G1 or G2 phase cells, which has important implications for DNA DSB repair in quiescent cells.
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Affiliation(s)
- Faith C Fowler
- Weill Cornell Medicine Pharmacology Graduate Program, New York, United States.,Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, United States
| | - Bo-Ruei Chen
- Department of Medicine, Division of Hematology and Oncology, O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, United States
| | - Nicholas Zolnerowich
- Laboratory of Genome Integrity, National Cancer Institute, Bethesda, United States
| | - Wei Wu
- Laboratory of Genome Integrity, National Cancer Institute, Bethesda, United States
| | - Raphael Pavani
- Laboratory of Genome Integrity, National Cancer Institute, Bethesda, United States
| | - Jacob Paiano
- Laboratory of Genome Integrity, National Cancer Institute, Bethesda, United States
| | - Chelsea Peart
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, United States
| | - Zulong Chen
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, United States
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, Bethesda, United States
| | - Barry P Sleckman
- Department of Medicine, Division of Hematology and Oncology, O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, United States
| | - Jessica K Tyler
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, United States
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14
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DNA Repair in Haploid Context. Int J Mol Sci 2021; 22:ijms222212418. [PMID: 34830299 PMCID: PMC8620282 DOI: 10.3390/ijms222212418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/08/2021] [Accepted: 11/14/2021] [Indexed: 12/15/2022] Open
Abstract
DNA repair is a well-covered topic as alteration of genetic integrity underlies many pathological conditions and important transgenerational consequences. Surprisingly, the ploidy status is rarely considered although the presence of homologous chromosomes dramatically impacts the repair capacities of cells. This is especially important for the haploid gametes as they must transfer genetic information to the offspring. An understanding of the different mechanisms monitoring genetic integrity in this context is, therefore, essential as differences in repair pathways exist that differentiate the gamete’s role in transgenerational inheritance. Hence, the oocyte must have the most reliable repair capacity while sperm, produced in large numbers and from many differentiation steps, are expected to carry de novo variations. This review describes the main DNA repair pathways with a special emphasis on ploidy. Differences between Saccharomyces cerevisiae and Schizosaccharomyces pombe are especially useful to this aim as they can maintain a diploid and haploid life cycle respectively.
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15
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Holland CL, Sanderson BA, Titus JK, Weis MF, Riojas AM, Malczewskyj E, Wasko BM, Lewis LK. Suppression of telomere capping defects of Saccharomyces cerevisiae yku70 and yku80 mutants by telomerase. G3-GENES GENOMES GENETICS 2021; 11:6395363. [PMID: 34718547 PMCID: PMC8664480 DOI: 10.1093/g3journal/jkab359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/27/2021] [Indexed: 11/18/2022]
Abstract
The Ku complex performs multiple functions inside eukaryotic cells, including protection of chromosomal DNA ends from degradation and fusion events, recruitment of telomerase, and repair of double-strand breaks (DSBs). Inactivation of Ku complex genes YKU70 or YKU80 in cells of the yeast Saccharomyces cerevisiae gives rise to mutants that exhibit shortened telomeres and temperature-sensitive growth. In this study, we have investigated the mechanism by which overexpression of telomerase suppresses the temperature sensitivity of yku mutants. Viability of yku cells was restored by overexpression of the Est2 reverse transcriptase and TLC1 RNA template subunits of telomerase, but not the Est1 or Est3 proteins. Overexpression of other telomerase- and telomere-associated proteins (Cdc13, Stn1, Ten1, Rif1, Rif2, Sir3, and Sir4) did not suppress the growth defects of yku70 cells. Mechanistic features of suppression were assessed using several TLC1 RNA deletion derivatives and Est2 enzyme mutants. Supraphysiological levels of three catalytically inactive reverse transcriptase mutants (Est2-D530A, Est2-D670A, and Est2-D671A) suppressed the loss of viability as efficiently as the wild-type Est2 protein, without inducing cell senescence. Roles of proteins regulating telomere length were also determined. The results support a model in which chromosomes in yku mutants are stabilized via a replication-independent mechanism involving structural reinforcement of protective telomere cap structures.
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Affiliation(s)
- Cory L Holland
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Brian A Sanderson
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - James K Titus
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Monica F Weis
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Angelica M Riojas
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Eric Malczewskyj
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Brian M Wasko
- Department of Biology and Biotechnology, University of Houston-Clear Lake, Houston, TX, 77058, USA
| | - L Kevin Lewis
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
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16
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Ahmad S, Côté V, Cheng X, Bourriquen G, Sapountzi V, Altaf M, Côté J. Antagonistic relationship of NuA4 with the non-homologous end-joining machinery at DNA damage sites. PLoS Genet 2021; 17:e1009816. [PMID: 34543274 PMCID: PMC8483352 DOI: 10.1371/journal.pgen.1009816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 09/30/2021] [Accepted: 09/09/2021] [Indexed: 11/19/2022] Open
Abstract
The NuA4 histone acetyltransferase complex, apart from its known role in gene regulation, has also been directly implicated in the repair of DNA double-strand breaks (DSBs), favoring homologous recombination (HR) in S/G2 during the cell cycle. Here, we investigate the antagonistic relationship of NuA4 with non-homologous end joining (NHEJ) factors. We show that budding yeast Rad9, the 53BP1 ortholog, can inhibit NuA4 acetyltransferase activity when bound to chromatin in vitro. While we previously reported that NuA4 is recruited at DSBs during the S/G2 phase, we can also detect its recruitment in G1 when genes for Rad9 and NHEJ factors Yku80 and Nej1 are mutated. This is accompanied with the binding of single-strand DNA binding protein RPA and Rad52, indicating DNA end resection in G1 as well as recruitment of the HR machinery. This NuA4 recruitment to DSBs in G1 depends on Mre11-Rad50-Xrs2 (MRX) and Lcd1/Ddc2 and is linked to the hyper-resection phenotype of NHEJ mutants. It also implicates NuA4 in the resection-based single-strand annealing (SSA) repair pathway along Rad52. Interestingly, we identified two novel non-histone acetylation targets of NuA4, Nej1 and Yku80. Acetyl-mimicking mutant of Nej1 inhibits repair of DNA breaks by NHEJ, decreases its interaction with other core NHEJ factors such as Yku80 and Lif1 and favors end resection. Altogether, these results establish a strong reciprocal antagonistic regulatory function of NuA4 and NHEJ factors in repair pathway choice and suggests a role of NuA4 in alternative repair mechanisms in situations where some DNA-end resection can occur in G1. DNA double-strand breaks (DSBs) are one of the most harmful form of DNA damage. Cells employ two major repair pathways to resolve DSBs: Homologous Recombination (HR) and Non-Homologous End Joining (NHEJ). Here we wanted to dissect further the role played by the NuA4 (Nucleosome acetyltransferase of histone H4) complex in the repair of DSBs. Budding yeast NuA4 complex, like its mammalian homolog TIP60 complex, has been shown to favor repair by HR. Here, we show that indeed budding yeast NuA4 and components of the NHEJ repair pathway share an antagonistic relationship. Deletion of NHEJ components enables increased recruitment of NuA4 in the vicinity of DSBs, possible through two independent mechanisms, where NuA4 favors the end resection process which implicates it in repair by single-strand annealing (SSA), an alternate homology-based repair pathway. Additionally, we also present two NHEJ core components as new targets of NuA4 acetyltransferase activity and suggest that these acetylation events can disassemble the NHEJ repair complex from DSBs, favoring repair by HR. Our study demonstrates the importance of NuA4 in the modulation of DSB repair pathway choice.
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Affiliation(s)
- Salar Ahmad
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Valérie Côté
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Xue Cheng
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Gaëlle Bourriquen
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Vasileia Sapountzi
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Mohammed Altaf
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Canada
- * E-mail:
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17
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Jessulat M, Amin S, Hooshyar M, Malty R, Moutaoufik MT, Zilocchi M, Istace Z, Phanse S, Aoki H, Omidi K, Burnside D, Samanfar B, Aly KA, Golshani A, Babu M. The conserved Tpk1 regulates non-homologous end joining double-strand break repair by phosphorylation of Nej1, a homolog of the human XLF. Nucleic Acids Res 2021; 49:8145-8160. [PMID: 34244791 PMCID: PMC8373142 DOI: 10.1093/nar/gkab585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 06/13/2021] [Accepted: 06/24/2021] [Indexed: 02/03/2023] Open
Abstract
The yeast cyclic AMP-dependent protein kinase A (PKA) is a ubiquitous serine-threonine kinase, encompassing three catalytic (Tpk1-3) and one regulatory (Bcy1) subunits. Evidence suggests PKA involvement in DNA damage checkpoint response, but how DNA repair pathways are regulated by PKA subunits remains inconclusive. Here, we report that deleting the tpk1 catalytic subunit reduces non-homologous end joining (NHEJ) efficiency, whereas tpk2-3 and bcy1 deletion does not. Epistatic analyses revealed that tpk1, as well as the DNA damage checkpoint kinase (dun1) and NHEJ factor (nej1), co-function in the same pathway, and parallel to the NHEJ factor yku80. Chromatin immunoprecipitation and resection data suggest that tpk1 deletion influences repair protein recruitments and DNA resection. Further, we show that Tpk1 phosphorylation of Nej1 at S298 (a Dun1 phosphosite) is indispensable for NHEJ repair and nuclear targeting of Nej1 and its binding partner Lif1. In mammalian cells, loss of PRKACB (human homolog of Tpk1) also reduced NHEJ efficiency, and similarly, PRKACB was found to phosphorylate XLF (a Nej1 human homolog) at S263, a corresponding residue of the yeast Nej1 S298. Together, our results uncover a new and conserved mechanism for Tpk1 and PRKACB in phosphorylating Nej1 (or XLF), which is critically required for NHEJ repair.
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Affiliation(s)
- Matthew Jessulat
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Shahreen Amin
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Mohsen Hooshyar
- Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1S5 B6, Canada
| | - Ramy Malty
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | | | - Mara Zilocchi
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Zoe Istace
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Sadhna Phanse
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Hiroyuki Aoki
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Katayoun Omidi
- Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1S5 B6, Canada
| | - Daniel Burnside
- Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1S5 B6, Canada
| | - Bahram Samanfar
- Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1S5 B6, Canada
| | - Khaled A Aly
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Ashkan Golshani
- Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1S5 B6, Canada
| | - Mohan Babu
- Department of Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
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18
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Complex Mechanisms of Antimony Genotoxicity in Budding Yeast Involves Replication and Topoisomerase I-Associated DNA Lesions, Telomere Dysfunction and Inhibition of DNA Repair. Int J Mol Sci 2021; 22:ijms22094510. [PMID: 33925940 PMCID: PMC8123508 DOI: 10.3390/ijms22094510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 11/26/2022] Open
Abstract
Antimony is a toxic metalloid with poorly understood mechanisms of toxicity and uncertain carcinogenic properties. By using a combination of genetic, biochemical and DNA damage assays, we investigated the genotoxic potential of trivalent antimony in the model organism Saccharomyces cerevisiae. We found that low doses of Sb(III) generate various forms of DNA damage including replication and topoisomerase I-dependent DNA lesions as well as oxidative stress and replication-independent DNA breaks accompanied by activation of DNA damage checkpoints and formation of recombination repair centers. At higher concentrations of Sb(III), moderately increased oxidative DNA damage is also observed. Consistently, base excision, DNA damage tolerance and homologous recombination repair pathways contribute to Sb(III) tolerance. In addition, we provided evidence suggesting that Sb(III) causes telomere dysfunction. Finally, we showed that Sb(III) negatively effects repair of double-strand DNA breaks and distorts actin and microtubule cytoskeleton. In sum, our results indicate that Sb(III) exhibits a significant genotoxic activity in budding yeast.
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19
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Zahid S, Seif El Dahan M, Iehl F, Fernandez-Varela P, Le Du MH, Ropars V, Charbonnier JB. The Multifaceted Roles of Ku70/80. Int J Mol Sci 2021; 22:ijms22084134. [PMID: 33923616 PMCID: PMC8073936 DOI: 10.3390/ijms22084134] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/11/2022] Open
Abstract
DNA double-strand breaks (DSBs) are accidental lesions generated by various endogenous or exogenous stresses. DSBs are also genetically programmed events during the V(D)J recombination process, meiosis, or other genome rearrangements, and they are intentionally generated to kill cancer during chemo- and radiotherapy. Most DSBs are processed in mammalian cells by the classical nonhomologous end-joining (c-NHEJ) pathway. Understanding the molecular basis of c-NHEJ has major outcomes in several fields, including radiobiology, cancer therapy, immune disease, and genome editing. The heterodimer Ku70/80 (Ku) is a central actor of the c-NHEJ as it rapidly recognizes broken DNA ends in the cell and protects them from nuclease activity. It subsequently recruits many c-NHEJ effectors, including nucleases, polymerases, and the DNA ligase 4 complex. Beyond its DNA repair function, Ku is also involved in several other DNA metabolism processes. Here, we review the structural and functional data on the DNA and RNA recognition properties of Ku implicated in DNA repair and in telomeres maintenance.
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20
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Tripuraneni V, Memisoglu G, MacAlpine HK, Tran TQ, Zhu W, Hartemink AJ, Haber JE, MacAlpine DM. Local nucleosome dynamics and eviction following a double-strand break are reversible by NHEJ-mediated repair in the absence of DNA replication. Genome Res 2021; 31:775-788. [PMID: 33811083 PMCID: PMC8092003 DOI: 10.1101/gr.271155.120] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/26/2021] [Indexed: 12/27/2022]
Abstract
We interrogated at nucleotide resolution the spatiotemporal order of chromatin changes that occur immediately following a site-specific double-strand break (DSB) upstream of the PHO5 locus and its subsequent repair by nonhomologous end joining (NHEJ). We observed the immediate eviction of a nucleosome flanking the break and the repositioning of adjacent nucleosomes away from the break. These early chromatin events were independent of the end-processing Mre11-Rad50-Xrs2 (MRX) complex and preceded the MRX-dependent broad eviction of histones and DNA end-resectioning that extends up to ∼8 kb away from the break. We also examined the temporal dynamics of NHEJ-mediated repair in a G1-arrested population. Concomitant with DSB repair by NHEJ, we observed the redeposition and precise repositioning of nucleosomes at their originally occupied positions. This re-establishment of the prelesion chromatin landscape suggests that a DNA replication-independent mechanism exists to preserve epigenome organization following DSB repair.
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Affiliation(s)
- Vinay Tripuraneni
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Gonen Memisoglu
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | - Heather K MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Trung Q Tran
- Department of Computer Science, Duke University, Durham, North Carolina 27708, USA
| | - Wei Zhu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - David M MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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21
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Misova I, Pitelova A, Budis J, Gazdarica J, Sedlackova T, Jordakova A, Benko Z, Smondrkova M, Mayerova N, Pichlerova K, Strieskova L, Prevorovsky M, Gregan J, Cipak L, Szemes T, Polakova SB. Repression of a large number of genes requires interplay between homologous recombination and HIRA. Nucleic Acids Res 2021; 49:1914-1934. [PMID: 33511417 PMCID: PMC7913671 DOI: 10.1093/nar/gkab027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 12/13/2022] Open
Abstract
During homologous recombination, Dbl2 protein is required for localisation of Fbh1, an F-box helicase that efficiently dismantles Rad51-DNA filaments. RNA-seq analysis of dbl2Δ transcriptome showed that the dbl2 deletion results in upregulation of more than 500 loci in Schizosaccharomyces pombe. Compared with the loci with no change in expression, the misregulated loci in dbl2Δ are closer to long terminal and long tandem repeats. Furthermore, the misregulated loci overlap with antisense transcripts, retrotransposons, meiotic genes and genes located in subtelomeric regions. A comparison of the expression profiles revealed that Dbl2 represses the same type of genes as the HIRA histone chaperone complex. Although dbl2 deletion does not alleviate centromeric or telomeric silencing, it suppresses the silencing defect at the outer centromere caused by deletion of hip1 and slm9 genes encoding subunits of the HIRA complex. Moreover, our analyses revealed that cells lacking dbl2 show a slight increase of nucleosomes at transcription start sites and increased levels of methylated histone H3 (H3K9me2) at centromeres, subtelomeres, rDNA regions and long terminal repeats. Finally, we show that other proteins involved in homologous recombination, such as Fbh1, Rad51, Mus81 and Rad54, participate in the same gene repression pathway.
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Affiliation(s)
- Ivana Misova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Alexandra Pitelova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Jaroslav Budis
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
| | - Juraj Gazdarica
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Tatiana Sedlackova
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
| | - Anna Jordakova
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Praha 2, Czechia
| | - Zsigmond Benko
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4010 Debrecen, Hungary
| | - Maria Smondrkova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Nina Mayerova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Karoline Pichlerova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Lucia Strieskova
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
| | - Martin Prevorovsky
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Praha 2, Czechia
| | - Juraj Gregan
- Advanced Microscopy Facility, VBCF and Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Lubos Cipak
- Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
| | - Tomas Szemes
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Silvia Bagelova Polakova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
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22
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Carballar R, Martínez-Láinez JM, Samper B, Bru S, Bállega E, Mirallas O, Ricco N, Clotet J, Jiménez J. CDK-mediated Yku80 Phosphorylation Regulates the Balance Between Non-homologous End Joining (NHEJ) and Homologous Directed Recombination (HDR). J Mol Biol 2020; 432:166715. [PMID: 33217428 DOI: 10.1016/j.jmb.2020.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 11/28/2022]
Abstract
There are two major pathways for repairing DNA double-strand breaks (DSBs): homologous directed recombination (HDR) and non-homologous end-joining (NHEJ). While NHEJ functions throughout the cell cycle, HDR is only possible during S/G2 phases, suggesting that there are cell cycle-specific mechanisms regulating the balance between the two repair systems. The regulation exerted by CDKs on HDR has been extensively demonstrated, and here we present evidence that the CDK Pho85, in association with the G1 cyclin Pcl1, phosphorylates Yku80 on Ser 623 to regulate NHEJ activity. Cells bearing a non-phosphorylatable version of Yku80 show increased NHEJ and reduced HDR activity. Accordingly, yku80S623A cells present diminished viability upon treatment with the DSB-producer bleomycin, specifically in the G2 phase of the cell cycle. Interestingly, the mutation of the equivalent residue in human Ku80 increases sensitivity to bleomycin in several cancer cell lines, suggesting that this mechanism is conserved in humans. Altogether, our results reveal a new mechanism whereby G1-CDKs mediate the choice between HDR and NHEJ repair pathways, putting the error prone NHEJ on a leash and enabling error free HDR in G2 when homologous sequences are available.
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Affiliation(s)
- Reyes Carballar
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Joan M Martínez-Láinez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Bàrbara Samper
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Samuel Bru
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Elisabet Bállega
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Oriol Mirallas
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Natalia Ricco
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Josep Clotet
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Javier Jiménez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
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23
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Britton S, Chanut P, Delteil C, Barboule N, Frit P, Calsou P. ATM antagonizes NHEJ proteins assembly and DNA-ends synapsis at single-ended DNA double strand breaks. Nucleic Acids Res 2020; 48:9710-9723. [PMID: 32890395 PMCID: PMC7515714 DOI: 10.1093/nar/gkaa723] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 07/29/2020] [Accepted: 08/21/2020] [Indexed: 12/15/2022] Open
Abstract
Two DNA repair pathways operate at DNA double strand breaks (DSBs): non-homologous end-joining (NHEJ), that requires two adjacent DNA ends for ligation, and homologous recombination (HR), that resects one DNA strand for invasion of a homologous duplex. Faithful repair of replicative single-ended DSBs (seDSBs) is mediated by HR, due to the lack of a second DNA end for end-joining. ATM stimulates resection at such breaks through multiple mechanisms including CtIP phosphorylation, which also promotes removal of the DNA-ends sensor and NHEJ protein Ku. Here, using a new method for imaging the recruitment of the Ku partner DNA-PKcs at DSBs, we uncover an unanticipated role of ATM in removing DNA-PKcs from seDSBs in human cells. Phosphorylation of DNA-PKcs on the ABCDE cluster is necessary not only for DNA-PKcs clearance but also for the subsequent MRE11/CtIP-dependent release of Ku from these breaks. We propose that at seDSBs, ATM activity is necessary for the release of both Ku and DNA-PKcs components of the NHEJ apparatus, and thereby prevents subsequent aberrant interactions between seDSBs accompanied by DNA-PKcs autophosphorylation and detrimental commitment to Lig4-dependent end-joining.
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Affiliation(s)
- Sébastien Britton
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
| | - Pauline Chanut
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
| | - Christine Delteil
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
| | - Nadia Barboule
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
| | - Philippe Frit
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
| | - Patrick Calsou
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- Equipe Labellisée Ligue contre le Cancer 2018, Toulouse, France
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24
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Young TZ, Liu P, Urbonaite G, Acar M. Quantitative Insights into Age-Associated DNA-Repair Inefficiency in Single Cells. Cell Rep 2020; 28:2220-2230.e7. [PMID: 31433994 PMCID: PMC6744837 DOI: 10.1016/j.celrep.2019.07.082] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 06/02/2019] [Accepted: 07/23/2019] [Indexed: 01/03/2023] Open
Abstract
Although double-strand break (DSB) repair is essential for a cell's survival, little is known about how DSB repair mechanisms are affected by age. Here we characterize the impact of cellular aging on the efficiency of single-strand annealing (SSA), a DSB repair mechanism. We measure SSA repair efficiency in young and old yeast cells and report a 23.4% decline in repair efficiency. This decline is not due to increased use of non-homologous end joining. Instead, we identify increased G1 phase duration in old cells as a factor responsible for the decreased SSA repair efficiency. Expression of 3xCLN2 leads to higher SSA repair efficiency in old cells compared with expression of 1xCLN2, confirming the involvement of cell-cycle regulation in age-associated repair inefficiency. Examining how SSA repair efficiency is affected by sequence heterology, we find that heteroduplex rejection remains high in old cells. Our work provides insights into the links between single-cell aging and DSB repair efficiency.
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Affiliation(s)
- Thomas Z Young
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Ping Liu
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Guste Urbonaite
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Murat Acar
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA; Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, 300 George Street, Suite 501, New Haven, CT 06511, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA.
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25
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Nej1 Interacts with Mre11 to Regulate Tethering and Dna2 Binding at DNA Double-Strand Breaks. Cell Rep 2020; 28:1564-1573.e3. [PMID: 31390569 PMCID: PMC6746346 DOI: 10.1016/j.celrep.2019.07.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/19/2019] [Accepted: 07/08/2019] [Indexed: 01/09/2023] Open
Abstract
Non-homologous end joining (NHEJ) and homologous recombination (HR) are the two major pathways of DNA double-strand break (DSB) repair and both are highly conserved from yeast to mammals. Nej1 has a role in DNA end-tethering at a DSB, and the Mre11/Rad50/Xrs2 (MRX) complex is important for its recruitment to the break. Nej1 and Dna2-Sgs1 interact with the C-terminal end of Mre11, which also includes the region where Rad50 binds. By characterizing the functionality of Nej1 in two rad50 mutants, which alter the structural features of MRX, we demonstrate that Nej1 inhibits the binding of Dna2 to Mre11 and Sgs1. Nej1 interactions with Mre11 promote tethering and inhibit hyper-resection, and when these events are compromised, large deletions develop at a DSB. The work indicates that Nej1 provides a layer of regulation to repair pathway choice and is consistent with its role in NHEJ. Mojumdar et al. characterize the role of Nej1 during double-strand break repair. They show Nej1 promotes non-homologous end joining (NHEJ) by tethering the broken DNA ends and by inhibiting hyper-resection mediated by Dna2-Sgs1.
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26
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Oster S, Aqeilan RI. Programmed DNA Damage and Physiological DSBs: Mapping, Biological Significance and Perturbations in Disease States. Cells 2020; 9:cells9081870. [PMID: 32785139 PMCID: PMC7463922 DOI: 10.3390/cells9081870] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/02/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double strand breaks (DSBs) are known to be the most toxic and threatening of the various types of breaks that may occur to the DNA. However, growing evidence continuously sheds light on the regulatory roles of programmed DSBs. Emerging studies demonstrate the roles of DSBs in processes such as T and B cell development, meiosis, transcription and replication. A significant recent progress in the last few years has contributed to our advanced knowledge regarding the functions of DSBs is the development of many next generation sequencing (NGS) methods, which have considerably advanced our capabilities. Other studies have focused on the implications of programmed DSBs on chromosomal aberrations and tumorigenesis. This review aims to summarize what is known about DNA damage in its physiological context. In addition, we will examine the advancements of the past several years, which have made an impact on the study of genome landscape and its organization.
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Affiliation(s)
- Sara Oster
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 9112001, Israel;
| | - Rami I. Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 9112001, Israel;
- Department of Cancer Biology and Genetics, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
- Correspondence:
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27
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Abstract
Cells confront DNA damage in every cell cycle. Among the most deleterious types of DNA damage are DNA double-strand breaks (DSBs), which can cause cell lethality if unrepaired or cancers if improperly repaired. In response to DNA DSBs, cells activate a complex DNA damage checkpoint (DDC) response that arrests the cell cycle, reprograms gene expression, and mobilizes DNA repair factors to prevent the inheritance of unrepaired and broken chromosomes. Here we examine the DDC, induced by DNA DSBs, in the budding yeast model system and in mammals.
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Affiliation(s)
- David P Waterman
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA;
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28
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Tisi R, Vertemara J, Zampella G, Longhese MP. Functional and structural insights into the MRX/MRN complex, a key player in recognition and repair of DNA double-strand breaks. Comput Struct Biotechnol J 2020; 18:1137-1152. [PMID: 32489527 PMCID: PMC7260605 DOI: 10.1016/j.csbj.2020.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
Chromosomal DNA double-strand breaks (DSBs) are potentially lethal DNA lesions that pose a significant threat to genome stability and therefore need to be repaired to preserve genome integrity. Eukaryotic cells possess two main mechanisms for repairing DSBs: non-homologous end-joining (NHEJ) and homologous recombination (HR). HR requires that the 5' terminated strands at both DNA ends are nucleolytically degraded by a concerted action of nucleases in a process termed DNA-end resection. This degradation leads to the formation of 3'-ended single-stranded DNA (ssDNA) ends that are essential to use homologous DNA sequences for repair. The evolutionarily conserved Mre11-Rad50-Xrs2/NBS1 complex (MRX/MRN) has enzymatic and structural activities to initiate DSB resection and to maintain the DSB ends tethered to each other for their repair. Furthermore, it is required to recruit and activate the protein kinase Tel1/ATM, which plays a key role in DSB signaling. All these functions depend on ATP-regulated DNA binding and nucleolytic activities of the complex. Several structures have been obtained in recent years for Mre11 and Rad50 subunits from archaea, and a few from the bacterial and eukaryotic orthologs. Nevertheless, the mechanism of activation of this protein complex is yet to be fully elucidated. In this review, we focused on recent biophysical and structural insights on the MRX complex and their interplay.
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Affiliation(s)
- Renata Tisi
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Jacopo Vertemara
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Giuseppe Zampella
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
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29
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Harpprecht L, Baldi S, Schauer T, Schmidt A, Bange T, Robles MS, Kremmer E, Imhof A, Becker PB. A Drosophila cell-free system that senses DNA breaks and triggers phosphorylation signalling. Nucleic Acids Res 2019; 47:7444-7459. [PMID: 31147711 PMCID: PMC6698661 DOI: 10.1093/nar/gkz473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 11/23/2022] Open
Abstract
Preblastoderm Drosophila embryo development is characterized by fast cycles of nuclear divisions. Extracts from these embryos can be used to reconstitute complex chromatin with high efficiency. We now discovered that this chromatin assembly system contains activities that recognize unprotected DNA ends and signal DNA damage through phosphorylation. DNA ends are initially bound by Ku and MRN complexes. Within minutes, the phosphorylation of H2A.V (homologous to γH2A.X) initiates from DNA breaks and spreads over tens of thousands DNA base pairs. The γH2A.V phosphorylation remains tightly associated with the damaged DNA and does not spread to undamaged DNA in the same reaction. This first observation of long-range γH2A.X spreading along damaged chromatin in an in vitro system provides a unique opportunity for mechanistic dissection. Upon further incubation, DNA ends are rendered single-stranded and bound by the RPA complex. Phosphoproteome analyses reveal damage-dependent phosphorylation of numerous DNA-end-associated proteins including Ku70, RPA2, CHRAC16, the exonuclease Rrp1 and the telomer capping complex. Phosphorylation of spindle assembly checkpoint components and of microtubule-associated proteins required for centrosome integrity suggests this cell-free system recapitulates processes involved in the regulated elimination of fatally damaged syncytial nuclei.
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Affiliation(s)
- Lisa Harpprecht
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Sandro Baldi
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
| | - Tamas Schauer
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Bioinformatics Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Andreas Schmidt
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Tanja Bange
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Maria S Robles
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, German Research Center for Environmental Health, 81377 Munich, Germany
| | - Axel Imhof
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Peter B Becker
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- To whom correspondence should be addressed. Tel: +49 89 2180 75427; Fax: +49 89 2180 75425;
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30
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Lucas BE, McPherson MT, Hawk TM, Wilson LN, Kroh JM, Hickman KG, Fitzgerald SR, Disbennett WM, Rollins PD, Hylton HM, Baseer MA, Montgomery PN, Wu JQ, Petreaca RC. An Assay to Study Intra-Chromosomal Deletions in Yeast. Methods Protoc 2019; 2:mps2030074. [PMID: 31454903 PMCID: PMC6789737 DOI: 10.3390/mps2030074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 01/30/2023] Open
Abstract
An accurate DNA damage response pathway is critical for the repair of DNA double-strand breaks. Repair may occur by homologous recombination, of which many different sub-pathways have been identified. Some recombination pathways are conservative, meaning that the chromosome sequences are preserved, and others are non-conservative, leading to some alteration of the DNA sequence. We describe an in vivo genetic assay to study non-conservative intra-chromosomal deletions at regions of non-tandem direct repeats in Schizosaccharomyces pombe. This assay can be used to study both spontaneous breaks arising during DNA replication and induced double-strand breaks created with the S. cerevisiae homothallic endonuclease (HO). The preliminary genetic validation of this assay shows that spontaneous breaks require rad52+ but not rad51+, while induced breaks require both genes, in agreement with previous studies. This assay will be useful in the field of DNA damage repair for studying mechanisms of intra-chromosomal deletions.
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Affiliation(s)
- Bailey E Lucas
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Matthew T McPherson
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Tila M Hawk
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Lexia N Wilson
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Jacob M Kroh
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Kyle G Hickman
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Sean R Fitzgerald
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | | | - P Daniel Rollins
- Molecular Genetics Program, The Ohio State University, Columbus, OH 43210, USA
| | - Hannah M Hylton
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Mohammed A Baseer
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Paige N Montgomery
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Ruben C Petreaca
- Department of Molecular Genetics, The Ohio State University, Marion, OH 43302, USA.
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31
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Marini F, Rawal CC, Liberi G, Pellicioli A. Regulation of DNA Double Strand Breaks Processing: Focus on Barriers. Front Mol Biosci 2019; 6:55. [PMID: 31380392 PMCID: PMC6646425 DOI: 10.3389/fmolb.2019.00055] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 07/01/2019] [Indexed: 12/11/2022] Open
Abstract
In all the eukaryotic cells, nucleolytic processing (resection) of a double strand DNA break (DSB) is a key step to channel the repair of the lesion toward the homologous recombination, at the expenses of the non-homologous end joining (NHEJ). The coordinated action of several nucleases and helicases generates 3′ single strand (ss) DNA, which is covered by RPA and recombination factors. Molecular details of the process have been first dissected in the model organism Saccharomyces cerevisiae. When DSB ends are occupied by KU, a central component of the NHEJ, the Mre11-Rad50-Xrs2 (MRX) nuclease complex (MRN in human), aided by the associated factors Sae2 (CTIP in human), initiates the resection process, inducing a nick close to the DSB ends. Then, starting from the nick, the nucleases Mre11, Exo1, Dna2, in cooperation with Sgs1 helicase (BLM in human), degrade DNA strand in both the directions, creating the 3′ ssDNA filament. Multiple levels of regulation of the break processing ensure faithful DSB repair, preventing chromosome rearrangements, and genome instability. Here we review the DSB resection process and its regulation in the context of chromatin. Particularly, we focus on proteins that limit DSB resection, acting as physical barriers toward nucleases and helicases. Moreover, we also take into consideration recent evidence regarding functional interplay between DSB repair and RNA molecules nearby the break site.
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Affiliation(s)
- Federica Marini
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Chetan C Rawal
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Giordano Liberi
- Istituto di Genetica Molecolare Luigi Luca Cavalli-Sforza, CNR, Pavia, Italy.,IFOM Foundation, Milan, Italy
| | - Achille Pellicioli
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
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32
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Casari E, Rinaldi C, Marsella A, Gnugnoli M, Colombo CV, Bonetti D, Longhese MP. Processing of DNA Double-Strand Breaks by the MRX Complex in a Chromatin Context. Front Mol Biosci 2019; 6:43. [PMID: 31231660 PMCID: PMC6567933 DOI: 10.3389/fmolb.2019.00043] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/21/2019] [Indexed: 12/24/2022] Open
Abstract
DNA double-strand breaks (DSBs) are highly cytotoxic lesions that must be repaired to ensure genomic stability and avoid cell death. The cellular response to DSBs is initiated by the evolutionarily conserved Mre11-Rad50-Xrs2/NBS1 (MRX/MRN) complex that has structural and catalytic functions. Furthermore, it is responsible for DSB signaling through the activation of the checkpoint kinase Tel1/ATM. Here, we review functions and regulation of the MRX/MRN complex in DSB processing in a chromatin context, as well as its interplay with Tel1/ATM.
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Affiliation(s)
| | | | | | | | | | | | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
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33
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MODIS Derived Sea Surface Salinity, Temperature, and Chlorophyll-a Data for Potential Fish Zone Mapping: West Red Sea Coastal Areas, Saudi Arabia. SENSORS 2019; 19:s19092069. [PMID: 31058844 PMCID: PMC6547357 DOI: 10.3390/s19092069] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 04/05/2019] [Accepted: 04/29/2019] [Indexed: 12/02/2022]
Abstract
In this study, a multi-linear regression model for potential fishing zone (PFZ) mapping along the Saudi Arabian Red Sea coasts of Yanbu’ al Bahr and Jeddah was developed, using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data derived parameters, such as sea surface salinity (SSS), sea surface temperature (SST), and chlorophyll-a (Chl-a). MODIS data was also used to validate the model. The model expanded on previous models by taking seasonal variances in PFZs into account, examining the impact of the summer, winter, monsoon, and inter-monsoon season on the selected oceanographic parameters in order to gain a deeper understanding of fish aggregation patterns. MODIS images were used to effectively extract SSS, SST, and Chl-a data for PFZ mapping. MODIS data were then used to perform multiple linear regression analysis in order to generate SSS, SST, and Chl-a estimates, with the estimates validated against in-situ data obtained from field visits completed at the time of the satellite passes. The proposed model demonstrates high potential for use in the Red Sea region, with a high level of congruence found between mapped PFZ areas and fish catch data (R2 = 0.91). Based on the results of this research, it is suggested that the proposed PFZ model is used to support fisheries in determining high potential fishing zones, allowing large areas of the Red Sea to be utilized over a short period. The proposed PFZ model can contribute significantly to the understanding of seasonal fishing activity and support the efficient, effective, and responsible use of resources within the fishing industry.
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34
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Bertrand C, Thibessard A, Bruand C, Lecointe F, Leblond P. Bacterial NHEJ: a never ending story. Mol Microbiol 2019; 111:1139-1151. [PMID: 30746801 DOI: 10.1111/mmi.14218] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2019] [Indexed: 12/30/2022]
Abstract
Double-strand breaks (DSBs) are the most detrimental DNA damage encountered by bacterial cells. DBSs can be repaired by homologous recombination thanks to the availability of an intact DNA template or by Non-Homologous End Joining (NHEJ) when no intact template is available. Bacterial NHEJ is performed by sets of proteins of growing complexity from Bacillus subtilis and Mycobacterium tuberculosis to Streptomyces and Sinorhizobium meliloti. Here, we discuss the contribution of these models to the understanding of the bacterial NHEJ repair mechanism as well as the involvement of NHEJ partners in other DNA repair pathways. The importance of NHEJ and of its complexity is discussed in the perspective of regulation through the biological cycle of the bacteria and in response to environmental stimuli. Finally, we consider the role of NHEJ in genome evolution, notably in horizontal gene transfer.
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Affiliation(s)
- Claire Bertrand
- Université de Lorraine, INRA, DynAMic, Nancy, F-54000, France
| | | | - Claude Bruand
- Laboratoire des Interactions Plantes-Microorganismes, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - François Lecointe
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Pierre Leblond
- Université de Lorraine, INRA, DynAMic, Nancy, F-54000, France
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35
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Stepwise 5' DNA end-specific resection of DNA breaks by the Mre11-Rad50-Xrs2 and Sae2 nuclease ensemble. Proc Natl Acad Sci U S A 2019; 116:5505-5513. [PMID: 30819891 DOI: 10.1073/pnas.1820157116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
To repair DNA double-strand breaks by homologous recombination, the 5'-terminated DNA strands must first be resected to produce 3' overhangs. Mre11 from Saccharomyces cerevisiae is a 3' → 5' exonuclease that is responsible for 5' end degradation in vivo. Using plasmid-length DNA substrates and purified recombinant proteins, we show that the combined exonuclease and endonuclease activities of recombinant MRX-Sae2 preferentially degrade the 5'-terminated DNA strand, which extends beyond the vicinity of the DNA end. Mechanistically, Rad50 restricts the Mre11 exonuclease in an ATP binding-dependent manner, preventing 3' end degradation. Phosphorylated Sae2, along with stimulating the MRX endonuclease as shown previously, also overcomes this inhibition to promote the 3' → 5' exonuclease of MRX, which requires ATP hydrolysis by Rad50. Our results support a model in which MRX-Sae2 catalyzes 5'-DNA end degradation by stepwise endonucleolytic DNA incisions, followed by exonucleolytic 3' → 5' degradation of the individual DNA fragments. This model explains how both exonuclease and endonuclease activities of Mre11 functionally integrate within the MRX-Sae2 ensemble to resect 5'-terminated DNA.
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36
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Bonetti D, Colombo CV, Clerici M, Longhese MP. Processing of DNA Ends in the Maintenance of Genome Stability. Front Genet 2018; 9:390. [PMID: 30258457 PMCID: PMC6143663 DOI: 10.3389/fgene.2018.00390] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/29/2018] [Indexed: 12/17/2022] Open
Abstract
DNA double-strand breaks (DSBs) are particularly hazardous lesions as their inappropriate repair can result in chromosome rearrangements, an important driving force of tumorigenesis. DSBs can be repaired by end joining mechanisms or by homologous recombination (HR). HR requires the action of several nucleases that preferentially remove the 5′-terminated strands at both DSB ends in a process called DNA end resection. The same nucleases are also involved in the processing of replication fork structures. Much of our understanding of these pathways has come from studies in the model organism Saccharomyces cerevisiae. Here, we review the current knowledge of the mechanism of resection at DNA DSBs and replication forks.
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Affiliation(s)
- Diego Bonetti
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | | | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
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37
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Gobbini E, Cassani C, Vertemara J, Wang W, Mambretti F, Casari E, Sung P, Tisi R, Zampella G, Longhese MP. The MRX complex regulates Exo1 resection activity by altering DNA end structure. EMBO J 2018; 37:embj.201798588. [PMID: 29925516 DOI: 10.15252/embj.201798588] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/24/2018] [Accepted: 05/30/2018] [Indexed: 01/19/2023] Open
Abstract
Homologous recombination is triggered by nucleolytic degradation (resection) of DNA double-strand breaks (DSBs). DSB resection requires the Mre11-Rad50-Xrs2 (MRX) complex, which promotes the activity of Exo1 nuclease through a poorly understood mechanism. Here, we describe the Mre11-R10T mutant variant that accelerates DSB resection compared to wild-type Mre11 by potentiating Exo1-mediated processing. This increased Exo1 resection activity leads to a decreased association of the Ku complex to DSBs and an enhanced DSB resection in G1, indicating that Exo1 has a direct function in preventing Ku association with DSBs. Molecular dynamics simulations show that rotation of the Mre11 capping domains is able to induce unwinding of double-strand DNA (dsDNA). The R10T substitution causes altered orientation of the Mre11 capping domain that leads to persistent melting of the dsDNA end. We propose that MRX creates a specific DNA end structure that promotes Exo1 resection activity by facilitating the persistence of this nuclease on the DSB ends, uncovering a novel MRX function in DSB resection.
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Affiliation(s)
- Elisa Gobbini
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Corinne Cassani
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Jacopo Vertemara
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Fabiana Mambretti
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Renata Tisi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Giuseppe Zampella
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
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38
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Fontana GA, Reinert JK, Thomä NH, Rass U. Shepherding DNA ends: Rif1 protects telomeres and chromosome breaks. MICROBIAL CELL 2018; 5:327-343. [PMID: 29992129 PMCID: PMC6035837 DOI: 10.15698/mic2018.07.639] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells have evolved conserved mechanisms to protect DNA ends, such as those at the termini of linear chromosomes, or those at DNA double-strand breaks (DSBs). In eukaryotes, DNA ends at chromosomal termini are packaged into proteinaceous structures called telomeres. Telomeres protect chromosome ends from erosion, inadvertent activation of the cellular DNA damage response (DDR), and telomere fusion. In contrast, cells must respond to damage-induced DNA ends at DSBs by harnessing the DDR to restore chromosome integrity, avoiding genome instability and disease. Intriguingly, Rif1 (Rap1-interacting factor 1) has been implicated in telomere homeostasis as well as DSB repair. The protein was first identified in Saccharomyces cerevisiae as being part of the proteinaceous telosome. In mammals, RIF1 is not associated with intact telomeres, but was found at chromosome breaks, where RIF1 has emerged as a key mediator of pathway choice between the two evolutionary conserved DSB repair pathways of non-homologous end-joining (NHEJ) and homologous recombination (HR). While this functional dichotomy has long been a puzzle, recent findings link yeast Rif1 not only to telomeres, but also to DSB repair, and mechanistic parallels likely exist. In this review, we will provide an overview of the actions of Rif1 at DNA ends and explore how exclusion of end-processing factors might be the underlying principle allowing Rif1 to fulfill diverse biological roles at telomeres and chromosome breaks.
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Affiliation(s)
- Gabriele A Fontana
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Julia K Reinert
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.,University of Basel, Petersplatz 10, CH-4003 Basel, Switzerland
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Ulrich Rass
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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39
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Suppressing Ku70/Ku80 expression elevates homology-directed repair efficiency in primary fibroblasts. Int J Biochem Cell Biol 2018; 99:154-160. [PMID: 29655920 DOI: 10.1016/j.biocel.2018.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/03/2018] [Accepted: 04/09/2018] [Indexed: 02/07/2023]
Abstract
The main DNA repair pathways, nonhomologous end joining (NHEJ) and homology-directed repair (HDR), are complementary to each other; hence, interruptions of the NHEJ pathway can favor HDR. Improving HDR efficiency in animal primary fibroblasts can facilitate the generation of gene knock-in animals with agricultural and biomedical values by somatic cell nuclear transfer. In this study, we used siRNA to suppress the expression of Ku70 and Ku80, which are the key factors in NHEJ pathway, to investigate the effect of Ku silencing on the HDR efficiency in pig fetal fibroblasts. Down-regulation of Ku70 and Ku80 resulted in the promotion of the frequencies of multiple HDR pathways, including homologous recombination, single strand annealing, and single-stranded oligonucleotide-mediated DNA repair. We further evaluated the effects of Ku70 and Ku80 silencing on promoting HR-mediated knock-in efficiency in two porcine endogenous genes and found a significant increase in the amount of knock-in cells in Ku-silenced fibroblasts compared with control. The RNA interference strategy will benefit the generation of cell lines and organisms with precise genetic modifications.
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40
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Ku DNA End-Binding Activity Promotes Repair Fidelity and Influences End-Processing During Nonhomologous End-Joining in Saccharomyces cerevisiae. Genetics 2018; 209:115-128. [PMID: 29500182 DOI: 10.1534/genetics.117.300672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 02/25/2018] [Indexed: 12/21/2022] Open
Abstract
The Ku heterodimer acts centrally in nonhomologous end-joining (NHEJ) of DNA double-strand breaks (DSB). Saccharomyces cerevisiae Ku, like mammalian Ku, binds and recruits NHEJ factors to DSB ends. Consequently, NHEJ is virtually absent in yeast Ku null (yku70∆ or yku80∆) strains. Previously, we unexpectedly observed imprecise NHEJ proficiency in a yeast Ku mutant with impaired DNA end-binding (DEB). However, how DEB impairment supported imprecise NHEJ was unknown. Here, we found imprecise NHEJ proficiency to be a feature of a panel of DEB-impaired Ku mutants and that DEB impairment resulted in a deficiency in precise NHEJ. These results suggest that DEB-impaired Ku specifically promotes error-prone NHEJ. Epistasis analysis showed that classical NHEJ factors, as well as novel and previously characterized NHEJ-specific residues of Ku, are required for the distinct error-prone repair in a Ku DEB mutant. However, sequencing of repair junctions revealed that imprecise repair in Ku DEB mutants was almost exclusively characterized by small deletions, in contrast to the majority of insertions that define imprecise repair in wild-type strains. Notably, while sequencing indicated a lack of Pol4-dependent insertions at the site of repair, Pol2 exonuclease activity, which mediates small deletions in NHEJ, contributed to imprecise NHEJ in a Ku DEB mutant. The deletions were smaller than in Ku-independent microhomology-mediated end-joining (MMEJ) and were neither promoted by Mre11 nuclease activity nor Sae2 Thus, the quality of Ku's engagement at the DNA end influences end-processing during NHEJ and DEB impairment unmasks a Ku-dependent error-prone pathway of end-joining distinct from MMEJ.
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41
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Reginato G, Cannavo E, Cejka P. Physiological protein blocks direct the Mre11-Rad50-Xrs2 and Sae2 nuclease complex to initiate DNA end resection. Genes Dev 2018; 31:2325-2330. [PMID: 29321179 PMCID: PMC5795779 DOI: 10.1101/gad.308254.117] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/07/2017] [Indexed: 11/16/2022]
Abstract
Reginato et al. report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5′-terminated DNA strands at break sites. Following initial endonucleolytic cleavage past the obstacle, Exo1 specifically extends the resection track, leading to the generation of long 3′ overhangs that are required for homologous recombination. DNA double-strand break repair by homologous recombination is initiated by DNA end resection, which is commenced by the Mre11–Rad50–Xrs2 complex and Sae2 in yeast. Here we report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5′-terminated DNA strands at break sites. Following initial endonucleolytic cleavage past the obstacle, Exo1 specifically extends the resection track, leading to the generation of long 3′ overhangs that are required for homologous recombination. These experiments provide mechanistic insights into how short-range and long-range DNA end resection enzymes overcome obstacles near broken DNA ends to initiate recombination.
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Affiliation(s)
- Giordano Reginato
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich 8093, Switzerland
| | - Elda Cannavo
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich 8093, Switzerland
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42
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Teixeira-Silva A, Ait Saada A, Hardy J, Iraqui I, Nocente MC, Fréon K, Lambert SAE. The end-joining factor Ku acts in the end-resection of double strand break-free arrested replication forks. Nat Commun 2017; 8:1982. [PMID: 29215009 PMCID: PMC5719404 DOI: 10.1038/s41467-017-02144-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 11/08/2017] [Indexed: 01/13/2023] Open
Abstract
Replication requires homologous recombination (HR) to stabilize and restart terminally arrested forks. HR-mediated fork processing requires single stranded DNA (ssDNA) gaps and not necessarily double strand breaks. We used genetic and molecular assays to investigate fork-resection and restart at dysfunctional, unbroken forks in Schizosaccharomyces pombe. Here, we report that fork-resection is a two-step process regulated by the non-homologous end joining factor Ku. An initial resection mediated by MRN-Ctp1 removes Ku from terminally arrested forks, generating ~110 bp sized gaps obligatory for subsequent Exo1-mediated long-range resection and replication restart. The mere lack of Ku impacts the processing of arrested forks, leading to an extensive resection, a reduced recruitment of RPA and Rad51 and a slower fork-restart process. We propose that terminally arrested forks undergo fork reversal, providing a single DNA end for Ku binding. We uncover a role for Ku in regulating end-resection of unbroken forks and in fine-tuning HR-mediated replication restart.
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Affiliation(s)
- Ana Teixeira-Silva
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Anissia Ait Saada
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Julien Hardy
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Ismail Iraqui
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Marina Charlotte Nocente
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Karine Fréon
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France.,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France
| | - Sarah A E Lambert
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, F-91405, France. .,University Paris Sud, Paris-Saclay University, CNRS, UMR3348, Orsay, F-91405, France.
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43
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Leshets M, Ramamurthy D, Lisby M, Lehming N, Pines O. Fumarase is involved in DNA double-strand break resection through a functional interaction with Sae2. Curr Genet 2017; 64:697-712. [DOI: 10.1007/s00294-017-0786-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/19/2017] [Accepted: 11/22/2017] [Indexed: 11/28/2022]
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44
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Saccharomyces cerevisiae Mhr1 can bind Xho I-induced mitochondrial DNA double-strand breaks in vivo. Mitochondrion 2017; 42:23-32. [PMID: 29032234 DOI: 10.1016/j.mito.2017.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 08/30/2017] [Accepted: 10/06/2017] [Indexed: 11/23/2022]
Abstract
Mitochondrial DNA (mtDNA) double-strand break (DSB) repair is essential for maintaining mtDNA integrity, but little is known about the proteins involved in mtDNA DSB repair. Here, we utilize Saccharomyces cerevisiae as a eukaryotic model to identify proteins involved in mtDNA DSB repair. We show that Mhr1, a protein known to possess homologous DNA pairing activity in vitro, binds to mtDNA DSBs in vivo, indicating its involvement in mtDNA DSB repair. Our data also indicate that Yku80, a protein previously implicated in mtDNA DSB repair, does not compete with Mhr1 for binding to mtDNA DSBs. In fact, C-terminally tagged Yku80 could not be detected in yeast mitochondrial extracts. Therefore, we conclude that Mhr1, but not Yku80, is a potential mtDNA DSB repair factor in yeast.
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45
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Sorenson KS, Mahaney BL, Lees-Miller SP, Cobb JA. The non-homologous end-joining factor Nej1 inhibits resection mediated by Dna2-Sgs1 nuclease-helicase at DNA double strand breaks. J Biol Chem 2017; 292:14576-14586. [PMID: 28679532 DOI: 10.1074/jbc.m117.796011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/03/2017] [Indexed: 12/25/2022] Open
Abstract
Double strand breaks (DSBs) represent highly deleterious DNA damage and need to be accurately repaired. Homology-directed repair and non-homologous end joining (NHEJ) are the two major DSB repair pathways that are highly conserved from yeast to mammals. The choice between these pathways is largely based on 5' to 3' DNA resection, and NHEJ proceeds only if resection has not been initiated. In yeast, yKu70/80 rapidly localizes to the break, protecting DNA ends from nuclease accessibility, and recruits additional NHEJ factors, including Nej1 and Lif1. Cells harboring the nej1-V338A mutant exhibit NHEJ-mediated repair deficiencies and hyper-resection 0.15 kb from the DSB that was dependent on the nuclease activity of Dna2-Sgs1. The integrity of Nej1 is also important for inhibiting long-range resection, 4.8 kb from the break, and for preventing the formation of large genomic deletions at sizes >700 bp around the break. Nej1V338A localized to a DSB similarly to WT Nej1, indicating that the Nej1-Lif1 interaction becomes critical for blocking hyper-resection mainly after their recruitment to the DSB. This work highlights that Nej1 inhibits 5' DNA hyper-resection mediated by Dna2-Sgs1, a function distinct from its previously reported role in supporting Dnl4 ligase activity, and has implications for repair pathway choice and resection regulation upon DSB formation.
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Affiliation(s)
- Kyle S Sorenson
- From the Departments of Biochemistry and Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive N. W., Calgary, Alberta T2N 4N1, Canada
| | - Brandi L Mahaney
- From the Departments of Biochemistry and Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive N. W., Calgary, Alberta T2N 4N1, Canada
| | - Susan P Lees-Miller
- From the Departments of Biochemistry and Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive N. W., Calgary, Alberta T2N 4N1, Canada
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46
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Shimada K, Gasser SM. A game of musical chairs: Pro- and anti-resection factors compete for TOPBP1 binding after DNA damage. J Cell Biol 2017; 216:535-537. [PMID: 28235945 PMCID: PMC5350523 DOI: 10.1083/jcb.201701038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Shimada and Gasser discuss new findings from the Smolka laboratory supporting a competitive model for nonhomologous end joining and homologous recombination factors at DNA breaks. DNA double strand breaks (DSBs) are generally repaired through nonhomologous end joining or homologous recombination. In this issue, Liu et al. (2017. J. Cell Biol.https://doi.org/10.1083/jcb.201607031) report that the conserved scaffold protein TOPBP1Dpb11 provides binding sites for both pro- and anti-resection factors at DSBs, providing insights into repair pathway regulation.
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Affiliation(s)
- Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
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47
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Anand R, Ranjha L, Cannavo E, Cejka P. Phosphorylated CtIP Functions as a Co-factor of the MRE11-RAD50-NBS1 Endonuclease in DNA End Resection. Mol Cell 2016; 64:940-950. [PMID: 27889449 DOI: 10.1016/j.molcel.2016.10.017] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/26/2016] [Accepted: 10/13/2016] [Indexed: 12/26/2022]
Abstract
To repair a DNA double-strand break (DSB) by homologous recombination (HR), the 5'-terminated strand of the DSB must be resected. The human MRE11-RAD50-NBS1 (MRN) and CtIP proteins were implicated in the initiation of DNA end resection, but the underlying mechanism remained undefined. Here, we show that CtIP is a co-factor of the MRE11 endonuclease activity within the MRN complex. This function is absolutely dependent on CtIP phosphorylation that includes the key cyclin-dependent kinase target motif at Thr-847. Unlike in yeast, where the Xrs2/NBS1 subunit is dispensable in vitro, NBS1 is absolutely required in the human system. The MRE11 endonuclease in conjunction with RAD50, NBS1, and phosphorylated CtIP preferentially cleaves 5'-terminated DNA strands near DSBs. Our results define the initial step of HR that is particularly relevant for the processing of DSBs bearing protein blocks.
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Affiliation(s)
- Roopesh Anand
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lepakshi Ranjha
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Elda Cannavo
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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48
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Guan J, Zhao Q, Mao W. Nuclear PTEN interferes with binding of Ku70 at double-strand breaks through post-translational poly(ADP-ribosyl)ation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:3106-3115. [PMID: 27741411 DOI: 10.1016/j.bbamcr.2016.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/27/2016] [Accepted: 10/07/2016] [Indexed: 01/12/2023]
Abstract
PTEN is a tumor suppressor gene characterized as a phosphatase that antagonizes the phosphatidylinositol 3-kinase signaling pathway in the cytoplasm. Nuclear PTEN plays roles in chromosomal stability, in which the double-strand breaks (DSB) repair mediated by homologous recombination (HR) and non-homologous end joining (NHEJ) is critical. Herein, the role of nuclear PTEN in DSB repair and the underlying molecular mechanism was investigated in this study. Using human breast cancer BT549 and MDA-MB-231 cell lines, we reveal a specific feature of PTEN that controls poly(ADP-ribosyl)ation of Ku70 and interferes with binding of Ku70 at DSB. Plasmid-based end joining and reporter assays showed that nuclear PTEN restrained NHEJ efficacy. Electrophoretic mobility shift assays showed that nuclear PTEN impaired Ku70 complex binding to DSB by 3-fold. Co-immunoprecipitation assay showed PTEN regulated poly(ADP-ribosyl)ation of Ku70 instead of directly interacting with Ku70, while PTEN promoted the poly(ADP-ribosyl)ation of PARP1 and induced the degradation of PARP1 in PTEN-WT cells exposed to DSB agents. Of note, the role of PTEN in DSB repair mostly depends on its nuclear localization rather than its phosphatase activity. As a result, the absence of nuclear PTEN rather than phosphatase-negative PTEN confers cell hypersensitivity to anti-tumor DNA damage drugs. This finding contributes to understanding the effect of PTEN in repair of DSB and using defined anti-tumor DSB drugs to treat tumor cells with aberrant PTEN.
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Affiliation(s)
- Jiawei Guan
- Department of Biotechnology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Qian Zhao
- Department of Biotechnology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Weifeng Mao
- Department of Biotechnology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China.
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49
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Villa M, Cassani C, Gobbini E, Bonetti D, Longhese MP. Coupling end resection with the checkpoint response at DNA double-strand breaks. Cell Mol Life Sci 2016; 73:3655-63. [PMID: 27141941 PMCID: PMC11108263 DOI: 10.1007/s00018-016-2262-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/08/2016] [Accepted: 04/29/2016] [Indexed: 10/21/2022]
Abstract
DNA double-strand breaks (DSBs) are a nasty form of damage that needs to be repaired to ensure genome stability. The DSB ends can undergo a strand-biased nucleolytic processing (resection) to generate 3'-ended single-stranded DNA (ssDNA) that channels DSB repair into homologous recombination. Generation of ssDNA also triggers the activation of the DNA damage checkpoint, which couples cell cycle progression with DSB repair. The checkpoint response is intimately linked to DSB resection, as some checkpoint proteins regulate the resection process. The present review will highlight recent works on the mechanism and regulation of DSB resection and its interplays with checkpoint activation/inactivation in budding yeast.
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Affiliation(s)
- Matteo Villa
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Corinne Cassani
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Elisa Gobbini
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Diego Bonetti
- Institute of Molecular Biology gGmbH (IMB), 55128, Mainz, Germany
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
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50
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Gobbini E, Cassani C, Villa M, Bonetti D, Longhese MP. Functions and regulation of the MRX complex at DNA double-strand breaks. MICROBIAL CELL (GRAZ, AUSTRIA) 2016; 3:329-337. [PMID: 28357369 PMCID: PMC5349012 DOI: 10.15698/mic2016.08.517] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/03/2016] [Indexed: 12/22/2022]
Abstract
DNA double-strand breaks (DSBs) pose a serious threat to genome stability and cell survival. Cells possess mechanisms that recognize DSBs and promote their repair through either homologous recombination (HR) or non-homologous end joining (NHEJ). The evolutionarily conserved Mre11-Rad50-Xrs2 (MRX) complex plays a central role in the cellular response to DSBs, as it is implicated in controlling end resection and in maintaining the DSB ends tethered to each other. Furthermore, it is responsible for DSB signaling by activating the checkpoint kinase Tel1 that, in turn, supports MRX function in a positive feedback loop. The present review focuses mainly on recent works in the budding yeast Saccharomyces cerevisiae to highlight structure and regulation of MRX as well as its interplays with Tel1.
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Affiliation(s)
- Elisa Gobbini
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Corinne Cassani
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Matteo Villa
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Diego Bonetti
- Institute of Molecular Biology gGmbH (IMB), 55128 Mainz, Germany
| | - Maria P. Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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