251
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Schrank B, Gautier J. Assembling nuclear domains: Lessons from DNA repair. J Cell Biol 2019; 218:2444-2455. [PMID: 31324649 PMCID: PMC6683749 DOI: 10.1083/jcb.201904202] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/24/2019] [Accepted: 06/27/2019] [Indexed: 12/14/2022] Open
Abstract
Schrank and Gautier discuss the generation and function of nuclear domains during DNA repair with a special focus on nuclear actin polymerization. Eukaryotic nuclei are organized into nuclear domains that unite loci sharing a common function. These domains are essential for diverse processes including (1) the formation of topologically associated domains (TADs) that coordinate replication and transcription, (2) the formation of specialized transcription and splicing factories, and (3) the clustering of DNA double-strand breaks (DSBs), which concentrates damaged DNA for repair. The generation of nuclear domains requires forces that are beginning to be identified. In the case of DNA DSBs, DNA movement and clustering are driven by actin filament nucleators. Furthermore, RNAs and low-complexity protein domains such as RNA-binding proteins also accumulate around sites of transcription and repair. The link between liquid–liquid phase separation and actin nucleation in the formation of nuclear domains is still unknown. This review discusses DSB repair domain formation as a model for functional nuclear domains in other genomic contexts.
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Affiliation(s)
- Benjamin Schrank
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY
| | - Jean Gautier
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY
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252
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Rozov SM, Permyakova NV, Deineko EV. The Problem of the Low Rates of CRISPR/Cas9-Mediated Knock-ins in Plants: Approaches and Solutions. Int J Mol Sci 2019; 20:E3371. [PMID: 31323994 PMCID: PMC6651222 DOI: 10.3390/ijms20133371] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 06/28/2019] [Accepted: 07/05/2019] [Indexed: 11/16/2022] Open
Abstract
The main number of genome editing events in plant objects obtained during the last decade with the help of specific nucleases zinc finger (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas are the microindels causing frameshift and subsequent gene knock-out. The knock-ins of genes or their parts, i.e., the insertion of them into a target genome region, are between one and two orders of magnitude less frequent. First and foremost, this is associated with the specific features of the repair systems of higher eukaryotes and the availability of the donor template in accessible proximity during double-strand break (DSB) repair. This review briefs the main repair pathways in plants according to the aspect of their involvement in genome editing. The main methods for increasing the frequency of knock-ins are summarized both along the homologous recombination pathway and non-homologous end joining, which can be used for plant objects.
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Affiliation(s)
- Serge M Rozov
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Natalya V Permyakova
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena V Deineko
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Plant Physiology and Biotechnology, Tomsk State University, Tomsk 634050, Russia
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253
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Abstract
DNA double-strand breaks (DSBs) are particularly challenging to repair in pericentromeric heterochromatin because of the increased risk of aberrant recombination in highly repetitive sequences. Recent studies have identified specialized mechanisms enabling 'safe' homologous recombination (HR) repair in heterochromatin. These include striking nuclear actin filaments (F-actin) and myosins that drive the directed motion of repair sites to the nuclear periphery for 'safe' repair. Here, we summarize our current understanding of the mechanisms involved, and propose how they might operate in the context of a phase-separated environment.
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254
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Olson HC, Davis L, Kiianitsa K, Khoo KJ, Liu Y, Knijnenburg TA, Maizels N. Increased levels of RECQ5 shift DNA repair from canonical to alternative pathways. Nucleic Acids Res 2019; 46:9496-9509. [PMID: 30107528 PMCID: PMC6182128 DOI: 10.1093/nar/gky727] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
RECQ5 (RECQL5) is one of several human helicases that dissociates RAD51-DNA filaments. The gene that encodes RECQ5 is frequently amplified in human tumors, but it is not known whether amplification correlates with increased gene expression, or how increased RECQ5 levels affect DNA repair at nicks and double-strand breaks. Here, we address these questions. We show that RECQ5 gene amplification correlates with increased gene expression in human tumors, by in silico analysis of over 9000 individual tumors representing 32 tumor types in the TCGA dataset. We demonstrate that, at double-strand breaks, increased RECQ5 levels inhibited canonical homology-directed repair (HDR) by double-stranded DNA donors, phenocopying the effect of BRCA deficiency. Conversely, at nicks, increased RECQ5 levels stimulated 'alternative' HDR by single-stranded DNA donors, which is normally suppressed by RAD51; this was accompanied by stimulation of mutagenic end-joining. Even modest changes (2-fold) in RECQ5 levels caused significant dysregulation of repair, especially HDR. These results suggest that in some tumors, RECQ5 gene amplification may have profound consequences for genomic instability.
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Affiliation(s)
- Henry C Olson
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Luther Davis
- Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Kostantin Kiianitsa
- Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Kevin J Khoo
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA.,Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Yilun Liu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, CA 91010, USA
| | - Theo A Knijnenburg
- Institute for Systems Biology, 401 Terry Ave. N., Seattle, WA 98109, USA
| | - Nancy Maizels
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA.,Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
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255
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Toma M, Skorski T, Sliwinski T. DNA Double Strand Break Repair - Related Synthetic Lethality. Curr Med Chem 2019; 26:1446-1482. [PMID: 29421999 DOI: 10.2174/0929867325666180201114306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/25/2022]
Abstract
Cancer is a heterogeneous disease with a high degree of diversity between and within tumors. Our limited knowledge of their biology results in ineffective treatment. However, personalized approach may represent a milestone in the field of anticancer therapy. It can increase specificity of treatment against tumor initiating cancer stem cells (CSCs) and cancer progenitor cells (CPCs) with minimal effect on normal cells and tissues. Cancerous cells carry multiple genetic and epigenetic aberrations which may disrupt pathways essential for cell survival. Discovery of synthetic lethality has led a new hope of creating effective and personalized antitumor treatment. Synthetic lethality occurs when simultaneous inactivation of two genes or their products causes cell death whereas individual inactivation of either gene is not lethal. The effectiveness of numerous anti-tumor therapies depends on induction of DNA damage therefore tumor cells expressing abnormalities in genes whose products are crucial for DNA repair pathways are promising targets for synthetic lethality. Here, we discuss mechanistic aspects of synthetic lethality in the context of deficiencies in DNA double strand break repair pathways. In addition, we review clinical trials utilizing synthetic lethality interactions and discuss the mechanisms of resistance.
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Affiliation(s)
- Monika Toma
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
| | - Tomasz Skorski
- Department of Microbiology and Immunology, 3400 North Broad Street, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, United States
| | - Tomasz Sliwinski
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
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256
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Todd RT, Wikoff TD, Forche A, Selmecki A. Genome plasticity in Candida albicans is driven by long repeat sequences. eLife 2019; 8:45954. [PMID: 31172944 PMCID: PMC6591007 DOI: 10.7554/elife.45954] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/07/2019] [Indexed: 11/13/2022] Open
Abstract
Genome rearrangements resulting in copy number variation (CNV) and loss of heterozygosity (LOH) are frequently observed during the somatic evolution of cancer and promote rapid adaptation of fungi to novel environments. In the human fungal pathogen Candida albicans, CNV and LOH confer increased virulence and antifungal drug resistance, yet the mechanisms driving these rearrangements are not completely understood. Here, we unveil an extensive array of long repeat sequences (65-6499 bp) that are associated with CNV, LOH, and chromosomal inversions. Many of these long repeat sequences are uncharacterized and encompass one or more coding sequences that are actively transcribed. Repeats associated with genome rearrangements are predominantly inverted and separated by up to ~1.6 Mb, an extraordinary distance for homology-based DNA repair/recombination in yeast. These repeat sequences are a significant source of genome plasticity across diverse strain backgrounds including clinical, environmental, and experimentally evolved isolates, and represent previously uncharacterized variation in the reference genome.
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Affiliation(s)
- Robert T Todd
- Creighton University Medical School, Omaha, United States
| | - Tyler D Wikoff
- Creighton University Medical School, Omaha, United States
| | | | - Anna Selmecki
- Creighton University Medical School, Omaha, United States
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257
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Farolfi A, Gurioli G, Fugazzola P, Burgio SL, Casanova C, Ravaglia G, Altavilla A, Costantini M, Amadori A, Framarini M, Ansaloni L, De Giorgi U. Immune System and DNA Repair Defects in Ovarian Cancer: Implications for Locoregional Approaches. Int J Mol Sci 2019; 20:E2569. [PMID: 31130614 PMCID: PMC6566239 DOI: 10.3390/ijms20102569] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/07/2019] [Accepted: 05/23/2019] [Indexed: 01/26/2023] Open
Abstract
In the last few years, substantial progress has been made in the treatment of ovarian cancer, with increased knowledge about the biology of the disease. Ovarian cancer is a neoplasm strongly linked to defects in DNA repair mechanisms, where deficiency in the homologous recombination (HR) system results in a better response of ovarian cancers to therapy, whether platinum-based chemotherapy, anthracyclines, or poly (ADP-ribose) polymerase (PARP) inhibitors. More recently, it has been demonstrated that different ovarian cancer histotypes may have different immunogenicity. Interestingly, defects in HR systems are associated more frequently with higher tumor infiltrating lymphocytes, providing a rationale for developing combination therapy with immune-modulating agents and PARP inhibitors. Again, locoregional therapies combining heat shock and chemotherapy delivery have been shown to induce an anticancer immune response in vitro. Thus, the potential for locoregional therapeutic approaches that may impact the immune system, perhaps in combination with immune-modulating agents or PARP inhibitors, needs to be further explored. With this premise, we reviewed the main biological and clinical data demonstrating a strict interplay between the immune system, DNA repair mechanisms, and intraperitoneal therapies in ovarian cancer, with a focus on potential future therapeutic implications.
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Affiliation(s)
- Alberto Farolfi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Giorgia Gurioli
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Paola Fugazzola
- General and Emergency Surgery, Maurizio Bufalini Hospital, Cesena 47521, Italy.
| | - Salvatore Luca Burgio
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Claudia Casanova
- Oncology Department, Santa Maria delle Croci Hospital, Ravenna 48121, Italy.
| | - Giorgia Ravaglia
- Unit of Biostatistics and Clinical Trials, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Amelia Altavilla
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | | | - Andrea Amadori
- Department of Gynecological, Morgagni-Pierantoni Hospital, Forlì 47121, Italy.
| | - Massimo Framarini
- Department of General Surgery, Morgagni-Pierantoni Hospital, Forlì 47121, Italy.
| | - Luca Ansaloni
- General and Emergency Surgery, Maurizio Bufalini Hospital, Cesena 47521, Italy.
| | - Ugo De Giorgi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
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258
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Liu J, François JM, Capp JP. Gene Expression Noise Produces Cell-to-Cell Heterogeneity in Eukaryotic Homologous Recombination Rate. Front Genet 2019; 10:475. [PMID: 31164905 PMCID: PMC6536703 DOI: 10.3389/fgene.2019.00475] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 05/03/2019] [Indexed: 11/13/2022] Open
Abstract
Variation in gene expression among genetically identical individual cells (called gene expression noise) directly contributes to phenotypic diversity. Whether such variation can impact genome stability and lead to variation in genotype remains poorly explored. We addressed this question by investigating whether noise in the expression of genes affecting homologous recombination (HR) activity either directly (RAD52) or indirectly (RAD27) confers cell-to-cell heterogeneity in HR rate in Saccharomyces cerevisiae. Using cell sorting to isolate subpopulations with various expression levels, we show that spontaneous HR rate is highly heterogeneous from cell-to-cell in clonal populations depending on the cellular amount of proteins affecting HR activity. Phleomycin-induced HR is even more heterogeneous, showing that RAD27 expression variation strongly affects the rate of recombination from cell-to-cell. Strong variations in HR rate between subpopulations are not correlated to strong changes in cell cycle stage. Moreover, this heterogeneity occurs even when simultaneously sorting cells at equal expression level of another gene involved in DNA damage response (BMH1) that is upregulated by DNA damage, showing that the initiating DNA damage is not responsible for the observed heterogeneity in HR rate. Thus gene expression noise seems mainly responsible for this phenomenon. Finally, HR rate non-linearly scales with Rad27 levels showing that total amount of HR cannot be explained solely by the time- or population-averaged Rad27 expression. Altogether, our data reveal interplay between heterogeneity at the gene expression and genetic levels in the production of phenotypic diversity with evolutionary consequences from microbial to cancer cell populations.
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Affiliation(s)
- Jian Liu
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
| | - Jean-Marie François
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
| | - Jean-Pascal Capp
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Institut National des Sciences Appliquées de Toulouse, UMR CNRS 5504, UMR INRA 792, Université de Toulouse, Toulouse, France
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259
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Doksani Y. The Response to DNA Damage at Telomeric Repeats and Its Consequences for Telomere Function. Genes (Basel) 2019; 10:genes10040318. [PMID: 31022960 PMCID: PMC6523756 DOI: 10.3390/genes10040318] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/13/2019] [Accepted: 04/18/2019] [Indexed: 01/17/2023] Open
Abstract
Telomeric repeats, coated by the shelterin complex, prevent inappropriate activation of the DNA damage response at the ends of linear chromosomes. Shelterin has evolved distinct solutions to protect telomeres from different aspects of the DNA damage response. These solutions include formation of t-loops, which can sequester the chromosome terminus from DNA-end sensors and inhibition of key steps in the DNA damage response. While blocking the DNA damage response at chromosome ends, telomeres make wide use of many of its players to deal with exogenous damage and replication stress. This review focuses on the interplay between the end-protection functions and the response to DNA damage occurring inside the telomeric repeats, as well as on the consequences that telomere damage has on telomere structure and function.
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Affiliation(s)
- Ylli Doksani
- IFOM, The FIRC Institute of Molecular Oncology, via Adamello 16, 20139 Milan, Italy.
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260
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Mechanistic modelling supports entwined rather than exclusively competitive DNA double-strand break repair pathway. Sci Rep 2019; 9:6359. [PMID: 31015540 PMCID: PMC6478946 DOI: 10.1038/s41598-019-42901-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 04/04/2019] [Indexed: 02/01/2023] Open
Abstract
Following radiation induced DNA damage, several repair pathways are activated to help preserve genome integrity. Double Strand Breaks (DSBs), which are highly toxic, have specified repair pathways to address them. The main repair pathways used to resolve DSBs are Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR). Cell cycle phase determines the availability of HR, but the repair choice between pathways in the G2 phases where both HR and NHEJ can operate is not clearly understood. This study compares several in silico models of repair choice to experimental data published in the literature, each model representing a different possible scenario describing how repair choice takes place. Competitive only scenarios, where initial protein recruitment determines repair choice, are unable to fit the literature data. In contrast, the scenario which uses a more entwined relationship between NHEJ and HR, incorporating protein co-localisation and RNF138-dependent removal of the Ku/DNA-PK complex, is better able to predict levels of repair similar to the experimental data. Furthermore, this study concludes that co-localisation of the Mre11-Rad50-Nbs1 (MRN) complexes, with initial NHEJ proteins must be modeled to accurately depict repair choice.
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261
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Lewis TW, Barthelemy JR, Virts EL, Kennedy FM, Gadgil RY, Wiek C, Linka RM, Zhang F, Andreassen PR, Hanenberg H, Leffak M. Deficiency of the Fanconi anemia E2 ubiqitin conjugase UBE2T only partially abrogates Alu-mediated recombination in a new model of homology dependent recombination. Nucleic Acids Res 2019; 47:3503-3520. [PMID: 30715513 PMCID: PMC6468168 DOI: 10.1093/nar/gkz026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 01/04/2019] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
The primary function of the UBE2T ubiquitin conjugase is in the monoubiquitination of the FANCI-FANCD2 heterodimer, a central step in the Fanconi anemia (FA) pathway. Genetic inactivation of UBE2T is responsible for the phenotypes of FANCT patients; however, a FANCT patient carrying a maternal duplication and a paternal deletion in the UBE2T loci displayed normal peripheral blood counts and UBE2T protein levels in B-lymphoblast cell lines. To test whether reversion by recombination between UBE2T AluYa5 elements could have occurred in the patient's hematopoietic stem cells despite the defects in homologous recombination (HR) in FA cells, we constructed HeLa cell lines containing the UBE2T AluYa5 elements and neighboring intervening sequences flanked by fluorescent reporter genes. Introduction of a DNA double strand break in the model UBE2T locus in vivo promoted single strand annealing (SSA) between proximal Alu elements and deletion of the intervening color marker gene, recapitulating the reversion of the UBE2T duplication in the FA patient. To test whether UBE2T null cells retain HR activity, the UBE2T genes were knocked out in HeLa cells and U2OS cells. CRISPR/Cas9-mediated genetic knockout of UBE2T only partially reduced HR, demonstrating that UBE2T-independent pathways can compensate for the recombination defect in UBE2T/FANCT null cells.
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Affiliation(s)
- Todd W Lewis
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Joanna R Barthelemy
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Elizabeth L Virts
- Department of Pediatrics and Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Felicia M Kennedy
- Department of Pediatrics and Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Rujuta Y Gadgil
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Constanze Wiek
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, 40225 Duüsseldorf, Germany
| | - Rene M Linka
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, 40225 Duüsseldorf, Germany
| | - Feng Zhang
- Division of Experimental Hematology & Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Paul R Andreassen
- Division of Experimental Hematology & Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Helmut Hanenberg
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, 40225 Duüsseldorf, Germany
- Department of Pediatrics III, University Children's Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Michael Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
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262
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263
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Son MY, Hasty P. Homologous recombination defects and how they affect replication fork maintenance. AIMS GENETICS 2019; 5:192-211. [PMID: 31435521 PMCID: PMC6690234 DOI: 10.3934/genet.2018.4.192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/18/2019] [Indexed: 01/07/2023]
Abstract
Homologous recombination (HR) repairs DNA double strand breaks (DSBs) and stabilizes replication forks (RFs). RAD51 is the recombinase for the HR pathway. To preserve genomic integrity, RAD51 forms a filament on the 3' end of a DSB and on a single-stranded DNA (ssDNA) gap. But unregulated HR results in undesirable chromosomal rearrangements. This review describes the multiple mechanisms that regulate HR with a focus on those mechanisms that promote and contain RAD51 filaments to limit chromosomal rearrangements. If any of these pathways break down and HR becomes unregulated then disease, primarily cancer, can result.
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Affiliation(s)
- Mi Young Son
- Department of Molecular Medicine and Institute of Biotechnology, UT Health San Antonio, 15355 Lambda Drive, San Antonio, USA
| | - Paul Hasty
- Department of Molecular Medicine and Institute of Biotechnology, UT Health San Antonio, 15355 Lambda Drive, San Antonio, USA
- The Mays Cancer Center, USA
- Sam and Ann Barshop Institute for Longevity and Aging Studies, USA
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264
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Li G, Zhang X, Ou H, Wang H, Liu D, Yang H, Wu Z. PIK-75 promotes homology-directed DNA repair. J Genet Genomics 2019; 46:141-144. [PMID: 30935856 DOI: 10.1016/j.jgg.2019.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/19/2019] [Accepted: 03/04/2019] [Indexed: 10/27/2022]
Affiliation(s)
- Guoling Li
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xianwei Zhang
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Hao Ou
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Haoqiang Wang
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Dewu Liu
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Huaqiang Yang
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China.
| | - Zhenfang Wu
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China.
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265
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Deng L, Wu RA, Sonneville R, Kochenova OV, Labib K, Pellman D, Walter JC. Mitotic CDK Promotes Replisome Disassembly, Fork Breakage, and Complex DNA Rearrangements. Mol Cell 2019; 73:915-929.e6. [PMID: 30849395 PMCID: PMC6410736 DOI: 10.1016/j.molcel.2018.12.021] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 10/03/2018] [Accepted: 12/21/2018] [Indexed: 12/27/2022]
Abstract
DNA replication errors generate complex chromosomal rearrangements and thereby contribute to tumorigenesis and other human diseases. One mechanism that triggers these errors is mitotic entry before the completion of DNA replication. To address how mitosis might affect DNA replication, we used Xenopus egg extracts. When mitotic CDK (Cyclin B1-CDK1) is used to drive interphase egg extracts into a mitotic state, the replicative CMG (CDC45/MCM2-7/GINS) helicase undergoes ubiquitylation on its MCM7 subunit, dependent on the E3 ubiquitin ligase TRAIP. Whether replisomes have stalled or undergone termination, CMG ubiquitylation is followed by its extraction from chromatin by the CDC48/p97 ATPase. TRAIP-dependent CMG unloading during mitosis is also seen in C. elegans early embryos. At stalled forks, CMG removal results in fork breakage and end joining events involving deletions and templated insertions. Our results identify a mitotic pathway of global replisome disassembly that can trigger replication fork collapse and DNA rearrangements.
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Affiliation(s)
- Lin Deng
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - R Alex Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - Remi Sonneville
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Olga V Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David Pellman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
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266
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Abstract
Fanconi anemia (FA) is a complex genetic disorder characterized by bone marrow failure (BMF), congenital defects, inability to repair DNA interstrand cross-links (ICLs), and cancer predisposition. FA presents two seemingly opposite characteristics: (a) massive cell death of the hematopoietic stem and progenitor cell (HSPC) compartment due to extensive genomic instability, leading to BMF, and (b) uncontrolled cell proliferation leading to FA-associated malignancies. The canonical function of the FA proteins is to collaborate with several other DNA repair proteins to eliminate clastogenic (chromosome-breaking) effects of DNA ICLs. Recent discoveries reveal that the FA pathway functions in a critical tumor-suppressor network to preserve genomic integrity by stabilizing replication forks, mitigating replication stress, and regulating cytokinesis. Homozygous germline mutations (biallelic) in 22 FANC genes cause FA, whereas heterozygous germline mutations in some of the FANC genes (monoallelic), such as BRCA1 and BRCA2, do not cause FA but significantly increase cancer susceptibility sporadically in the general population. In this review, we discuss our current understanding of the functions of the FA pathway in the maintenance of genomic stability, and we present an overview of the prevalence and clinical relevance of somatic mutations in FA genes.
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Affiliation(s)
- Joshi Niraj
- Department of Radiation Oncology and Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA;
| | - Anniina Färkkilä
- Department of Radiation Oncology and Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA;
| | - Alan D D'Andrea
- Department of Radiation Oncology and Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA;
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267
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Impeding the single-strand annealing pathway of DNA double-strand break repair by withaferin A-mediated FANCA degradation. DNA Repair (Amst) 2019; 77:10-17. [PMID: 30844655 DOI: 10.1016/j.dnarep.2019.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/13/2019] [Accepted: 02/20/2019] [Indexed: 12/18/2022]
Abstract
FANCA is a key player in the canonical Fanconi anemia (FA) repair pathway. We have recently shown that FANCA also plays an important role in the single-strand annealing sub-pathway (SSA) of DNA double-strand break (DSB) repair by biochemically catalyzing single-strand annealing. Here, we report that a steroidal lactone withaferin A (WA) specifically impedes SSA repair by promoting FANCA downregulation at a sub-micromolar concentration range. We find that WA causes FANCA downregulation post-translationally in a proteasome-dependent manner. This WA-mediated downregulation is achieved through HSP90 inhibition and disruption of the FANCA-HSP90 interaction. WA-mediated FANCA degradation significantly reduces cellular SSA repair, abolishes FANCD2 monoubiquitination, elevates sensitivity to mitomycin C, and results in accumulation of DSBs. Importantly, the WA-induced defect in SSA repair is highly dependent on the absence of FANCA protein and overexpression of exogenous WT-FANCA protein in WA-treated cells significantly complements the repair defect.
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268
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Murthy P, Muggia F. Women's cancers: how the discovery of BRCA genes is driving current concepts of cancer biology and therapeutics. Ecancermedicalscience 2019; 13:904. [PMID: 30915162 PMCID: PMC6411414 DOI: 10.3332/ecancer.2019.904] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Indexed: 12/15/2022] Open
Abstract
Over the last two decades, discoveries related to the breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) have profoundly changed our understanding and management of hereditary breast and ovarian cancers. The concept of synthetic lethality, which arises when cells become vulnerable to a combination of deficiencies in DNA repair, has driven the expanding roles of poly (adenosine diphosphate (ADP)-ribose) polymerase inhibitors in breast and ovarian cancers, and prevention strategies are taking into account the tissue specificity, natural history (fallopian tube origin of some high-grade serous ovarian cancers) and hormone sensitivity of BRCA-associated cancers. Current research has focussed on further elucidating the roles of BRCA proteins in DNA repair, investigating other key DNA repair processes and proteins and linking aberrant DNA repair with carcinogenesis. The ultimate goal is to translate this evolving knowledge into improving the clinical care and treatment of patients with pathogenic BRCA variants or other deficiencies in homologous recombination (HR). In this review, we will discuss 1) the role of BRCA proteins in DNA repair; 2) emerging concepts in the biology of HR deficiency and 3) implications for prevention and treatment.
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Affiliation(s)
- Pooja Murthy
- New York University School of Medicine, New York, NY 10016, USA
- Maimonides Cancer Center, Brooklyn, NY 11220, USA
| | - Franco Muggia
- New York University School of Medicine, New York, NY 10016, USA
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269
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Piazza A, Heyer WD. Homologous Recombination and the Formation of Complex Genomic Rearrangements. Trends Cell Biol 2019; 29:135-149. [PMID: 30497856 PMCID: PMC6402879 DOI: 10.1016/j.tcb.2018.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 12/13/2022]
Abstract
The maintenance of genome integrity involves multiple independent DNA damage avoidance and repair mechanisms. However, the origin and pathways of the focal chromosomal reshuffling phenomena collectively referred to as chromothripsis remain mechanistically obscure. We discuss here the role, mechanisms, and regulation of homologous recombination (HR) in the formation of simple and complex chromosomal rearrangements. We emphasize features of the recently characterized multi-invasion (MI)-induced rearrangement (MIR) pathway which uniquely amplifies the initial DNA damage. HR intermediates and cellular contexts that endanger genomic stability are discussed as well as the emerging roles of various classes of nucleases in the formation of genome rearrangements. Long-read sequencing and improved mapping of repeats should enable better appreciation of the significance of recombination in generating genomic rearrangements.
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Affiliation(s)
- Aurèle Piazza
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; Spatial Regulation of Genomes, Department of Genomes and Genetics, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 3525, Institut Pasteur, 75015 Paris, France
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
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270
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Bae W, Hong S, Park MS, Jeong HK, Lee MH, Koo HS. Single-strand annealing mediates the conservative repair of double-strand DNA breaks in homologous recombination-defective germ cells of Caenorhabditis elegans. DNA Repair (Amst) 2019; 75:18-28. [PMID: 30710866 DOI: 10.1016/j.dnarep.2019.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 11/25/2022]
Abstract
A missense mutation in C. elegans RAD-54, a homolog of RAD54 that operates in the homologous recombination (HR) pathway, was found to decrease ATPase activity in vitro. The hypomorphic mutation caused hypersensitivity of C. elegans germ cells to double-strand DNA breaks (DSBs). Although the formation of RAD-51 foci at DSBs was normal in both the mutant and knockdown worms, their subsequent dissipation was slow. The rad-54-deficient phenotypes were greatly aggravated when combined with an xpf-1 mutation, suggesting a conservative role of single-strand annealing (SSA) for DSB repair in HR-defective worms. The phenotypes of doubly-deficient rad-54;xpf-1 worms were partially suppressed by a mutation of lig-4, a nonhomologous end-joining (NHEJ) factor. In summary, RAD-54 is required for the dissociation of RAD-51 from DSB sites in C. elegans germ cells. Also, NHEJ and SSA exert negative and positive effects, respectively, on genome stability when HR is defective.
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Affiliation(s)
- Woori Bae
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, 03772, Seoul, Republic of Korea
| | - Seokbong Hong
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, 03772, Seoul, Republic of Korea
| | - Mi So Park
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, 03772, Seoul, Republic of Korea
| | - Ha-Kyeong Jeong
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, 03772, Seoul, Republic of Korea
| | - Myon-Hee Lee
- Department of Medicine, Hematology/Oncology Division, Brody School of Medicine at East Carolina University, Greenville, NC, 27834, United States
| | - Hyeon-Sook Koo
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, 03772, Seoul, Republic of Korea.
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271
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Rogers CM, Sausen CW, Bochman ML. Gel-Based Assays for Measuring DNA Unwinding, Annealing, and Strand Exchange. Methods Mol Biol 2019; 1999:255-264. [PMID: 31127582 DOI: 10.1007/978-1-4939-9500-4_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Efficient replication and repair of the genome requires a multitude of protein-DNA transactions. These interactions can result in a variety of consequences for DNA such as the unwinding of double-stranded DNA (dsDNA) into single-stranded DNA (ssDNA), the annealing of complementary ssDNAs, or the exchange of ssDNA with one strand of a dsDNA duplex. Some DNA helicases possess all three activities, but many DNA-interacting proteins can also catalyze one or more of these reactions. Assays that quantify these activities are an important first step in characterizing these protein-DNA interactions in vitro. Here, we describe methods for the formation of dsDNA substrates and the assays that can be used to biochemically characterize proteins that can unwind, anneal, and/or exchange DNA strands.
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Affiliation(s)
- Cody M Rogers
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Christopher W Sausen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Matthew L Bochman
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA.
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272
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Yamamoto Y, Gerbi SA. Making ends meet: targeted integration of DNA fragments by genome editing. Chromosoma 2018; 127:405-420. [PMID: 30003320 PMCID: PMC6330168 DOI: 10.1007/s00412-018-0677-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/25/2018] [Accepted: 06/28/2018] [Indexed: 12/27/2022]
Abstract
Targeted insertion of large pieces of DNA is an important goal of genetic engineering. However, this goal has been elusive since classical methods for homology-directed repair are inefficient and often not feasible in many systems. Recent advances are described here that enable site-specific genomic insertion of relatively large DNA with much improved efficiency. Using the preferred repair pathway in the cell of nonhomologous end-joining, DNA of up to several kb could be introduced with remarkably good precision by the methods of HITI and ObLiGaRe with an efficiency up to 30-40%. Recent advances utilizing homology-directed repair (methods of PITCh; short homology arms including ssODN; 2H2OP) have significantly increased the efficiency for DNA insertion, often to 40-50% or even more depending on the method and length of DNA. The remaining challenges of integration precision and off-target site insertions are summarized. Overall, current advances provide major steps forward for site-specific insertion of large DNA into genomes from a broad range of cells and organisms.
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Affiliation(s)
- Yutaka Yamamoto
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University Division of Biology and Medicine, Sidney Frank Hall room 260, 185 Meeting Street, Providence, RI, 02912, USA
| | - Susan A Gerbi
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University Division of Biology and Medicine, Sidney Frank Hall room 260, 185 Meeting Street, Providence, RI, 02912, USA.
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273
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Portugez S, Martin WF, Hazkani-Covo E. Mosaic mitochondrial-plastid insertions into the nuclear genome show evidence of both non-homologous end joining and homologous recombination. BMC Evol Biol 2018; 18:162. [PMID: 30390623 PMCID: PMC6215612 DOI: 10.1186/s12862-018-1279-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/18/2018] [Indexed: 02/06/2023] Open
Abstract
Background Mitochondrial and plastid DNA fragments are continuously transferred into eukaryotic nuclear genomes, giving rise to nuclear copies of mitochondrial DNA (numts) and nuclear copies of plastid DNA (nupts). Numts and nupts are classified as simple if they are composed of a single organelle fragment or as complex if they are composed of multiple fragments. Mosaic insertions are complex insertions composed of fragments of both mitochondrial and plastid DNA. Simple numts and nupts in eukaryotes have been extensively studied, their mechanism of insertion involves non-homologous end joining (NHEJ). Mosaic insertions have been less well-studied and their mechanisms of integration are unknown. Results Here we estimated the number of nuclear mosaic insertions (numins) in nine plant genomes. We show that numins compose up to 10% of the total nuclear insertions of organelle DNA in these plant genomes. The NHEJ hallmarks typical for numts and nupts were also identified in mosaic insertions. However, the number of identified insertions that integrated via NHEJ mechanism is underestimated, as NHEJ signatures are conserved only in recent insertions and mutationally eroded in older ones. A few complex insertions show signatures of long homology that cannot be attributed to NHEJ, a novel observation that implicates gene conversion or single strand annealing mechanisms in organelle nuclear insertions. Conclusions The common NHEJ signature that was identified here reveals that, in plant cells, mitochondria and plastid fragments in numins must meet during or prior to integration into the nuclear genome. Electronic supplementary material The online version of this article (10.1186/s12862-018-1279-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shir Portugez
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, Israel.,School of Molecular Cell Biology & Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - William F Martin
- Institute of Molecular Evolution, Heinrich-Heine University, Düsseldorf, Germany
| | - Einat Hazkani-Covo
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, Israel.
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274
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Smirnikhina SA, Anuchina AA, Lavrov AV. Ways of improving precise knock-in by genome-editing technologies. Hum Genet 2018; 138:1-19. [DOI: 10.1007/s00439-018-1953-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/29/2018] [Indexed: 02/07/2023]
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275
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Palovcak A, Liu W, Yuan F, Zhang Y. Stitching up broken DNA ends by FANCA. Mol Cell Oncol 2018; 5:e1518101. [PMID: 30525096 DOI: 10.1080/23723556.2018.1518101] [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: 08/15/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 12/27/2022]
Abstract
RAD52 rejoins resected broken DNA ends by mediating single-strand annealing. Our recent work elucidates that FANCA, a Fanconi anemia protein, also directly repairs double-strand breaks (DSBs) by catalyzing annealing of single-stranded DNA. FANCA and RAD52 likely play complementary roles to each other to prevent deleterious consequences of DSBs. Abbreviations: DSBs: DNA double-strand breaks; ICL: interstrand crosslink; ssDNA: single-stranded DNA; HR: homologous recombination; SSA: single-strand annealing; MMEJ: microhomology-mediated end joining; NHEJ: non-homologous end joining; GFP: green fluorescence protein.
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Affiliation(s)
- Anna Palovcak
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, USA
| | - Wenjun Liu
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, USA
| | - Fenghua Yuan
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, USA
| | - Yanbin Zhang
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, USA
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276
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Meiotic Double-Strand Break Proteins Influence Repair Pathway Utilization. Genetics 2018; 210:843-856. [PMID: 30242011 DOI: 10.1534/genetics.118.301402] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/13/2018] [Indexed: 12/13/2022] Open
Abstract
Double-strand breaks (DSBs) are among the most deleterious lesions DNA can endure. Yet, DSBs are programmed at the onset of meiosis, and are required to facilitate appropriate reduction of ploidy in daughter cells. Repair of these breaks is tightly controlled to favor homologous recombination (HR)-the only repair pathway that can form crossovers. However, little is known about how the activities of alternative repair pathways are regulated at these stages. We discovered an unexpected synthetic interaction between the DSB machinery and strand-exchange proteins. Depleting the Caenorhabditis elegans DSB-promoting factors HIM-5 and DSB-2 suppresses the formation of chromosome fusions that arise in the absence of RAD-51 or other strand-exchange mediators. Our investigations reveal that nonhomologous and theta-mediated end joining (c-NHEJ and TMEJ, respectively) and single strand annealing (SSA) function redundantly to repair DSBs when HR is compromised, and that HIM-5 influences the utilization of TMEJ and SSA.
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277
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Gene cloning and seamless site-directed mutagenesis using single-strand annealing (SSA). Appl Microbiol Biotechnol 2018; 102:10119-10126. [PMID: 30209551 DOI: 10.1007/s00253-018-9348-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/16/2018] [Accepted: 08/27/2018] [Indexed: 12/17/2022]
Abstract
The full length of interested genes can be usually cloned by assembling exons or RACE products through overlap PCR. However, the procedure requires multiple PCR steps, which are prone to random mutagenesis. Here, we present a novel SSA-based method for gene cloning and seamless site-directed mutagenesis. We firstly cloned the full-length coding sequence of Cashmere goat (Capra hircus) Hoxc13 gene by assembling exons amplified from genomic DNA. Secondly, we created a Hoxc13 loss-function mutant seamlessly and further illustrated that direct repeat length of 25 bp is enough to trigger the SSA repair in routine E. coli strains including DH5α, Trans1t1, JM109, and Top10. Moreover, we cloned another full-length mutant of Foxn1 gene from Cashmere goat cDNA using further shortened direct repeats of 19 bp. In summary, our study provided an alternative method to overcome the difficulties during overlap PCR in some particular cases for gene cloning.
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278
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Abstract
53BP1 restrains DNA end resection, and its dosage imbalance upsets DNA double-strand break (DSB) repair pathway choice. Here, by monitoring 53BP1 distribution on DSB-flanking chromatin, we have established a dose-dependent role of the RING finger protein RNF169 in limiting 53BP1 DSB deposition. Moreover, we found that forced expression of RNF169 overcomes 53BP1 activity and stimulates mutagenic DSB repair via the single-strand annealing pathway. Our findings suggest that aberrant expression of RNF169 may represent a deleterious factor in DSB repair control and in maintenance of genome stability. Unrestrained 53BP1 activity at DNA double-strand breaks (DSBs) hampers DNA end resection and upsets DSB repair pathway choice. RNF169 acts as a molecular rheostat to limit 53BP1 deposition at DSBs, but how this fine balance translates to DSB repair control remains undefined. In striking contrast to 53BP1, ChIP analyses of AsiSI-induced DSBs unveiled that RNF169 exhibits robust accumulation at DNA end-proximal regions and preferentially targets resected, RPA-bound DSBs. Accordingly, we found that RNF169 promotes CtIP-dependent DSB resection and favors homology-mediated DSB repair, and further showed that RNF169 dose-dependently stimulates single-strand annealing repair, in part, by alleviating the 53BP1-imposed barrier to DSB end resection. Our results highlight the interplay of RNF169 with 53BP1 in fine-tuning choice of DSB repair pathways.
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279
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Song X, Beck CR, Du R, Campbell IM, Coban-Akdemir Z, Gu S, Breman AM, Stankiewicz P, Ira G, Shaw CA, Lupski JR. Predicting human genes susceptible to genomic instability associated with Alu/ Alu-mediated rearrangements. Genome Res 2018; 28:1228-1242. [PMID: 29907612 PMCID: PMC6071635 DOI: 10.1101/gr.229401.117] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 06/06/2018] [Indexed: 12/14/2022]
Abstract
Alu elements, the short interspersed element numbering more than 1 million copies per human genome, can mediate the formation of copy number variants (CNVs) between substrate pairs. These Alu/Alu-mediated rearrangements (AAMRs) can result in pathogenic variants that cause diseases. To investigate the impact of AAMR on gene variation and human health, we first characterized Alus that are involved in mediating CNVs (CNV-Alus) and observed that these Alus tend to be evolutionarily younger. We then computationally generated, with the assistance of a supercomputer, a test data set consisting of 78 million Alu pairs and predicted ∼18% of them are potentially susceptible to AAMR. We further determined the relative risk of AAMR in 12,074 OMIM genes using the count of predicted CNV-Alu pairs and experimentally validated the predictions with 89 samples selected by correlating predicted hotspots with a database of CNVs identified by clinical chromosomal microarrays (CMAs) on the genomes of approximately 54,000 subjects. We fine-mapped 47 duplications, 40 deletions, and two complex rearrangements and examined a total of 52 breakpoint junctions of simple CNVs. Overall, 94% of the candidate breakpoints were at least partially Alu mediated. We successfully predicted all (100%) of Alu pairs that mediated deletions (n = 21) and achieved an 87% positive predictive value overall when including AAMR-generated deletions and duplications. We provided a tool, AluAluCNVpredictor, for assessing AAMR hotspots and their role in human disease. These results demonstrate the utility of our predictive model and provide insights into the genomic features and molecular mechanisms underlying AAMR.
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Affiliation(s)
- Xiaofei Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Christine R Beck
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Renqian Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Ian M Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Amy M Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Texas Children's Hospital, Houston, Texas 77030, USA
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280
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The concerted roles of FANCM and Rad52 in the protection of common fragile sites. Nat Commun 2018; 9:2791. [PMID: 30022024 PMCID: PMC6052092 DOI: 10.1038/s41467-018-05066-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/10/2018] [Indexed: 12/18/2022] Open
Abstract
Common fragile sites (CFSs) are prone to chromosomal breakage and are hotspots for chromosomal rearrangements in cancer cells. We uncovered a novel function of Fanconi anemia (FA) protein FANCM in the protection of CFSs that is independent of the FA core complex and the FANCI–FANCD2 complex. FANCM, along with its binding partners FAAP24 and MHF1/2, is recruited to CFS-derived structure-prone AT-rich sequences, where it suppresses DNA double-strand break (DSB) formation and mitotic recombination in a manner dependent on FANCM translocase activity. Interestingly, we also identified an indispensable function of Rad52 in the repair of DSBs at CFS-derived AT-rich sequences, despite its nonessential function in general homologous recombination (HR) in mammalian cells. Suppression of Rad52 expression in combination with FANCM knockout drastically reduces cell and tumor growth, suggesting a synthetic lethality interaction between these two genes, which offers a potential targeted treatment strategy for FANCM-deficient tumors with Rad52 inhibition. Fanconi anemia core proteins have been linked to common fragile site stability. Here the authors shed light into the role of FANCM in common fragile site protection by suppressing double-strand break formation and mitotic recombination.
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281
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Maeda T, Kobayashi Y, Kameoka H, Okuma N, Takeda N, Yamaguchi K, Bino T, Shigenobu S, Kawaguchi M. Evidence of non-tandemly repeated rDNAs and their intragenomic heterogeneity in Rhizophagus irregularis. Commun Biol 2018; 1:87. [PMID: 30271968 PMCID: PMC6123716 DOI: 10.1038/s42003-018-0094-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 06/12/2018] [Indexed: 01/21/2023] Open
Abstract
Arbuscular mycorrhizal fungus (AMF) species are some of the most widespread symbionts of land plants. Our much improved reference genome assembly of a model AMF, Rhizophagus irregularis DAOM-181602 (total contigs = 210), facilitated a discovery of repetitive elements with unusual characteristics. R. irregularis has only ten or 11 copies of complete 45S rDNAs, whereas the general eukaryotic genome has tens to thousands of rDNA copies. R. irregularis rDNAs are highly heterogeneous and lack a tandem repeat structure. These findings provide evidence for the hypothesis that rDNA heterogeneity depends on the lack of tandem repeat structures. RNA-Seq analysis confirmed that all rDNA variants are actively transcribed. Observed rDNA/rRNA polymorphisms may modulate translation by using different ribosomes depending on biotic and abiotic interactions. The non-tandem repeat structure and intragenomic heterogeneity of AMF rDNA/rRNA may facilitate successful adaptation to various environmental conditions, increasing host compatibility of these symbiotic fungi.
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Affiliation(s)
- Taro Maeda
- Division of Symbiotic Systems, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
| | - Yuuki Kobayashi
- Division of Symbiotic Systems, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
| | - Hiromu Kameoka
- Division of Symbiotic Systems, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
| | - Nao Okuma
- Division of Symbiotic Systems, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
- The Graduate University for Advanced Studies [SOKENDAI], Hayama, Miura, Kanagawa, 240-0193, Japan
| | - Naoya Takeda
- School of Science and Technology, Kwansei Gakuin University, Gakuen, Mita, Hyogo, 669-1337, Japan
| | - Katsushi Yamaguchi
- Functional Genomics Facility, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
| | - Takahiro Bino
- Functional Genomics Facility, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan
| | - Shuji Shigenobu
- The Graduate University for Advanced Studies [SOKENDAI], Hayama, Miura, Kanagawa, 240-0193, Japan.
- Functional Genomics Facility, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan.
| | - Masayoshi Kawaguchi
- Division of Symbiotic Systems, National Institute for Basic Biology, Myodaiji Nishigonaka, Okazaki, Aichi, 444-8585, Japan.
- The Graduate University for Advanced Studies [SOKENDAI], Hayama, Miura, Kanagawa, 240-0193, Japan.
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282
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Ma Y, Vassetzky Y, Dokudovskaya S. mTORC1 pathway in DNA damage response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1293-1311. [PMID: 29936127 DOI: 10.1016/j.bbamcr.2018.06.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 12/27/2022]
Abstract
Living organisms have evolved various mechanisms to control their metabolism and response to various stresses, allowing them to survive and grow in different environments. In eukaryotes, the highly conserved mechanistic target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of cellular metabolism, proliferation and survival. A growing body of evidence indicates that mTOR signaling is closely related to another cellular protection mechanism, the DNA damage response (DDR). Many factors important for the DDR are also involved in the mTOR pathway. In this review, we discuss how these two pathways communicate to ensure an efficient protection of the cell against metabolic and genotoxic stresses. We also describe how anticancer therapies benefit from simultaneous targeting of the DDR and mTOR pathways.
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Affiliation(s)
- Yinxing Ma
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Yegor Vassetzky
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Svetlana Dokudovskaya
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France.
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283
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Prakash A, Garcia-Moreno JF, Brown JAL, Bourke E. Clinically Applicable Inhibitors Impacting Genome Stability. Molecules 2018; 23:E1166. [PMID: 29757235 PMCID: PMC6100577 DOI: 10.3390/molecules23051166] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 12/14/2022] Open
Abstract
Advances in technology have facilitated the molecular profiling (genomic and transcriptomic) of tumours, and has led to improved stratification of patients and the individualisation of treatment regimes. To fully realize the potential of truly personalised treatment options, we need targeted therapies that precisely disrupt the compensatory pathways identified by profiling which allow tumours to survive or gain resistance to treatments. Here, we discuss recent advances in novel therapies that impact the genome (chromosomes and chromatin), pathways targeted and the stage of the pathways targeted. The current state of research will be discussed, with a focus on compounds that have advanced into trials (clinical and pre-clinical). We will discuss inhibitors of specific DNA damage responses and other genome stability pathways, including those in development, which are likely to synergistically combine with current therapeutic options. Tumour profiling data, combined with the knowledge of new treatments that affect the regulation of essential tumour signalling pathways, is revealing fundamental insights into cancer progression and resistance mechanisms. This is the forefront of the next evolution of advanced oncology medicine that will ultimately lead to improved survival and may, one day, result in many cancers becoming chronic conditions, rather than fatal diseases.
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Affiliation(s)
- Anu Prakash
- Discipline of Pathology, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - Juan F Garcia-Moreno
- Discipline of Surgery, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - James A L Brown
- Discipline of Surgery, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - Emer Bourke
- Discipline of Pathology, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
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284
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Piazza A, Heyer WD. Multi-Invasion-Induced Rearrangements as a Pathway for Physiological and Pathological Recombination. Bioessays 2018; 40:e1700249. [PMID: 29578583 PMCID: PMC6072258 DOI: 10.1002/bies.201700249] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/08/2018] [Indexed: 01/24/2023]
Abstract
Cells mitigate the detrimental consequences of DNA damage on genome stability by attempting high fidelity repair. Homologous recombination templates DNA double-strand break (DSB) repair on an identical or near identical donor sequence in a process that can in principle access the entire genome. Other physiological processes, such as homolog recognition and pairing during meiosis, also harness the HR machinery using programmed DSBs to physically link homologs and generate crossovers. A consequence of the homology search process by a long nucleoprotein filament is the formation of multi-invasions (MI), a joint molecule in which the damaged ssDNA has invaded more than one donor molecule. Processing of MI joint molecules can compromise the integrity of both donor sites and lead to their rearrangement. Here, two mechanisms for the generation of rearrangements as a pathological consequence of MI processing are detailed and the potential relevance for non-allelic homologous recombination discussed. Finally, it is proposed that MI-induced crossover formation may be a feature of physiological recombination.
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Affiliation(s)
- Aurèle Piazza
- Department of Microbiology and Molecular Genetics, One Shields Avenue, University of California, Davis, CA, 95616, USA
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, One Shields Avenue, University of California, Davis, CA, 95616, USA
- Department of Molecular and Cellular Biology, One Shields Avenue, University of California, Davis, CA, 95616, USA
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285
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Structural Basis of Homology-Directed DNA Repair Mediated by RAD52. iScience 2018; 3:50-62. [PMID: 30428330 PMCID: PMC6137706 DOI: 10.1016/j.isci.2018.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/07/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
RAD52 mediates homologous recombination by annealing cDNA strands. However, the detailed mechanism of DNA annealing promoted by RAD52 has remained elusive. Here we report two crystal structures of human RAD52 single-stranded DNA (ssDNA) complexes that probably represent key reaction intermediates of RAD52-mediated DNA annealing. The first structure revealed a "wrapped" conformation of ssDNA around the homo-oligomeric RAD52 ring, in which the edges of the bases involved in base pairing are exposed to the solvent. The ssDNA conformation is close to B-form and appears capable of engaging in Watson-Crick base pairing with the cDNA strand. The second structure revealed a "trapped" conformation of ssDNA between two RAD52 rings. This conformation is stabilized by a different RAD52 DNA binding site, which promotes the accumulation of multiple RAD52 rings on ssDNA and the aggregation of ssDNA. These structures provide a structural framework for understanding the mechanism of RAD52-mediated DNA annealing.
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286
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Mendez-Dorantes C, Bhargava R, Stark JM. Repeat-mediated deletions can be induced by a chromosomal break far from a repeat, but multiple pathways suppress such rearrangements. Genes Dev 2018; 32:524-536. [PMID: 29636371 PMCID: PMC5959236 DOI: 10.1101/gad.311084.117] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/20/2018] [Indexed: 12/20/2022]
Abstract
Here, Mendez-Dorantes et al. investigated how far a chromosomal double-strand break (DSB) can be positioned from a repeat sequence to induce repeat-mediated rearrangements in mammalian cells. Using a novel reporter assay in mouse embryonic stem cells, they found that a DSB separated from the 3′ repeat by 28.4 kb can still substantially induce RMDs, indicating that a DSB is sufficient to induce RMDs at a relatively far distance. Chromosomal deletion rearrangements mediated by repetitive elements often involve repeats separated by several kilobases and sequences that are divergent. While such rearrangements are likely induced by DNA double-strand breaks (DSBs), it has been unclear how the proximity of DSBs relative to repeat sequences affects the frequency of such events. We generated a reporter assay in mouse cells for a deletion rearrangement involving repeats separated by 0.4 Mb. We induced this repeat-mediated deletion (RMD) rearrangement with two DSBs: the 5′ DSB that is just downstream from the first repeat and the 3′ DSB that is varying distances upstream of the second repeat. Strikingly, we found that increasing the 3′ DSB/repeat distance from 3.3 kb to 28.4 kb causes only a modest decrease in rearrangement frequency. We also found that RMDs are suppressed by KU70 and RAD51 and promoted by RAD52, CtIP, and BRCA1. In addition, we found that 1%–3% sequence divergence substantially suppresses these rearrangements in a manner dependent on the mismatch repair factor MSH2, which is dominant over the suppressive role of KU70. We suggest that a DSB far from a repeat can stimulate repeat-mediated rearrangements, but multiple pathways suppress these events.
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Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Cancer Genetics and Epigenetics, City of Hope, Duarte, California 91010, USA.,Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, California 91010, USA
| | - Ragini Bhargava
- Department of Cancer Genetics and Epigenetics, City of Hope, Duarte, California 91010, USA.,Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, California 91010, USA
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, City of Hope, Duarte, California 91010, USA.,Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, California 91010, USA
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287
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Andriuskevicius T, Kotenko O, Makovets S. Putting together and taking apart: assembly and disassembly of the Rad51 nucleoprotein filament in DNA repair and genome stability. Cell Stress 2018; 2:96-112. [PMID: 31225474 PMCID: PMC6551702 DOI: 10.15698/cst2018.05.134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Homologous recombination is a key mechanism providing both genome stability and genetic diversity in all living organisms. Recombinases play a central role in this pathway: multiple protein subunits of Rad51 or its orthologues bind single-stranded DNA to form a nucleoprotein filament which is essential for initiating recombination events. Multiple factors are involved in the regulation of this step, both positively and negatively. In this review, we discuss Rad51 nucleoprotein assembly and disassembly, how it is regulated and what functional significance it has in genome maintenance.
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Affiliation(s)
| | - Oleksii Kotenko
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh
| | - Svetlana Makovets
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh
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288
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Sallmyr A, Tomkinson AE. Repair of DNA double-strand breaks by mammalian alternative end-joining pathways. J Biol Chem 2018. [PMID: 29530982 DOI: 10.1074/jbc.tm117.000375] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alternative end-joining (a-EJ) pathways, which repair DNA double-strand breaks (DSBs), are initiated by end resection that generates 3' single strands. This reaction is shared, at least in part, with homologous recombination but distinguishes a-EJ from the major nonhomologous end-joining pathway. Although the a-EJ pathways make only a minor and poorly understood contribution to DSB repair in nonmalignant cells, there is growing interest in these pathways, as they generate genomic rearrangements that are hallmarks of cancer cells. Here, we review and discuss the current understanding of the mechanisms and regulation of a-EJ pathways, the role of a-EJ in human disease, and the potential utility of a-EJ as a therapeutic target in cancer.
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Affiliation(s)
- Annahita Sallmyr
- From the Departments of Internal Medicine and Molecular Genetics and Microbiology, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico 87131
| | - Alan E Tomkinson
- From the Departments of Internal Medicine and Molecular Genetics and Microbiology, University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico 87131
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289
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Brustel J, Kozik Z, Gromak N, Savic V, Sweet SMM. Large XPF-dependent deletions following misrepair of a DNA double strand break are prevented by the RNA:DNA helicase Senataxin. Sci Rep 2018; 8:3850. [PMID: 29497062 PMCID: PMC5832799 DOI: 10.1038/s41598-018-21806-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/09/2018] [Indexed: 01/04/2023] Open
Abstract
Deletions and chromosome re-arrangements are common features of cancer cells. We have established a new two-component system reporting on epigenetic silencing or deletion of an actively transcribed gene adjacent to a double-strand break (DSB). Unexpectedly, we find that a targeted DSB results in a minority (<10%) misrepair event of kilobase deletions encompassing the DSB site and transcribed gene. Deletions are reduced upon RNaseH1 over-expression and increased after knockdown of the DNA:RNA helicase Senataxin, implicating a role for DNA:RNA hybrids. We further demonstrate that the majority of these large deletions are dependent on the 3′ flap endonuclease XPF. DNA:RNA hybrids were detected by DNA:RNA immunoprecipitation in our system after DSB generation. These hybrids were reduced by RNaseH1 over-expression and increased by Senataxin knock-down, consistent with a role in deletions. Overall, these data are consistent with DNA:RNA hybrid generation at the site of a DSB, mis-processing of which results in genome instability in the form of large deletions.
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Affiliation(s)
- Julien Brustel
- Genome Damage and Stability Centre (GDSC), University of Sussex, Brighton, BN1 9RQ, UK
| | - Zuzanna Kozik
- Genome Damage and Stability Centre (GDSC), University of Sussex, Brighton, BN1 9RQ, UK
| | - Natalia Gromak
- Sir William Dunn School of Pathology, University of Oxford, Oxford, South Parks Road, OX1 3RE, UK
| | - Velibor Savic
- Brighton and Sussex Medical School (BSMS), University of Sussex, Brighton, BN1 9RQ, UK.,Horizon Discovery Ltd, 8100 Cambridge Research Park, Cambridge, CB25 9TL, UK
| | - Steve M M Sweet
- Genome Damage and Stability Centre (GDSC), University of Sussex, Brighton, BN1 9RQ, UK. .,NantOmics, 9600 Medical Center Drive, Rockville, MD, 20850, USA.
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290
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Her J, Bunting SF. How cells ensure correct repair of DNA double-strand breaks. J Biol Chem 2018; 293:10502-10511. [PMID: 29414795 DOI: 10.1074/jbc.tm118.000371] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
DNA double-strand breaks (DSBs) arise regularly in cells and when left unrepaired cause senescence or cell death. Homologous recombination (HR) and nonhomologous end-joining (NHEJ) are the two major DNA-repair pathways. Whereas HR allows faithful DSB repair and healthy cell growth, NHEJ has higher potential to contribute to mutations and malignancy. Many regulatory mechanisms influence which of these two pathways is used in DSB repair. These mechanisms depend on the cell cycle, post-translational modifications, and chromatin effects. Here, we summarize current research into these mechanisms, with a focus on mammalian cells, and also discuss repair by "alternative end-joining" and single-strand annealing.
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Affiliation(s)
- Joonyoung Her
- From the Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway, New Jersey 08540
| | - Samuel F Bunting
- From the Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway, New Jersey 08540
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291
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Uckelmann M, Densham RM, Baas R, Winterwerp HHK, Fish A, Sixma TK, Morris JR. USP48 restrains resection by site-specific cleavage of the BRCA1 ubiquitin mark from H2A. Nat Commun 2018; 9:229. [PMID: 29335415 PMCID: PMC5768779 DOI: 10.1038/s41467-017-02653-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022] Open
Abstract
BRCA1-BARD1-catalyzed ubiquitination of histone H2A is an important regulator of the DNA damage response, priming chromatin for repair by homologous recombination. However, no specific deubiquitinating enzymes (DUBs) are known to antagonize this function. Here we identify ubiquitin specific protease-48 (USP48) as a H2A DUB, specific for the C-terminal BRCA1 ubiquitination site. Detailed biochemical analysis shows that an auxiliary ubiquitin, an additional ubiquitin that itself does not get cleaved, modulates USP48 activity, which has possible implications for its regulation in vivo. In cells we reveal that USP48 antagonizes BRCA1 E3 ligase function and in BRCA1-proficient cells loss of USP48 results in positioning 53BP1 further from the break site and in extended resection lengths. USP48 repression confers a survival benefit to cells treated with camptothecin and its activity acts to restrain gene conversion and mutagenic single-strand annealing. We propose that USP48 promotes genome stability by antagonizing BRCA1 E3 ligase function.
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Affiliation(s)
- Michael Uckelmann
- Division of Biochemistry and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Ruth M Densham
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, Medical and Dental Schools, University of Birmingham, Birmingham, B15 2TT, UK
| | - Roy Baas
- Division of Biochemistry and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Herrie H K Winterwerp
- Division of Biochemistry and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Alexander Fish
- Division of Biochemistry and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Titia K Sixma
- Division of Biochemistry and Cancer Genomics Centre, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| | - Joanna R Morris
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, Medical and Dental Schools, University of Birmingham, Birmingham, B15 2TT, UK.
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292
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Ranjha L, Howard SM, Cejka P. Main steps in DNA double-strand break repair: an introduction to homologous recombination and related processes. Chromosoma 2018; 127:187-214. [PMID: 29327130 DOI: 10.1007/s00412-017-0658-1] [Citation(s) in RCA: 209] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/15/2017] [Accepted: 12/19/2017] [Indexed: 12/16/2022]
Abstract
DNA double-strand breaks arise accidentally upon exposure of DNA to radiation and chemicals or result from faulty DNA metabolic processes. DNA breaks can also be introduced in a programmed manner, such as during the maturation of the immune system, meiosis, or cancer chemo- or radiotherapy. Cells have developed a variety of repair pathways, which are fine-tuned to the specific needs of a cell. Accordingly, vegetative cells employ mechanisms that restore the integrity of broken DNA with the highest efficiency at the lowest cost of mutagenesis. In contrast, meiotic cells or developing lymphocytes exploit DNA breakage to generate diversity. Here, we review the main pathways of eukaryotic DNA double-strand break repair with the focus on homologous recombination and its various subpathways. We highlight the differences between homologous recombination and end-joining mechanisms including non-homologous end-joining and microhomology-mediated end-joining and offer insights into how these pathways are regulated. Finally, we introduce noncanonical functions of the recombination proteins, in particular during DNA replication stress.
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Affiliation(s)
- Lepakshi Ranjha
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Sean M Howard
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland. .,Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.
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293
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Pannunzio NR, Watanabe G, Lieber MR. Nonhomologous DNA end-joining for repair of DNA double-strand breaks. J Biol Chem 2017; 293:10512-10523. [PMID: 29247009 DOI: 10.1074/jbc.tm117.000374] [Citation(s) in RCA: 326] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nonhomologous DNA end-joining (NHEJ) is the predominant double-strand break (DSB) repair pathway throughout the cell cycle and accounts for nearly all DSB repair outside of the S and G2 phases. NHEJ relies on Ku to thread onto DNA termini and thereby improve the affinity of the NHEJ enzymatic components consisting of polymerases (Pol μ and Pol λ), a nuclease (the Artemis·DNA-PKcs complex), and a ligase (XLF·XRCC4·Lig4 complex). Each of the enzymatic components is distinctive for its versatility in acting on diverse incompatible DNA end configurations coupled with a flexibility in loading order, resulting in many possible junctional outcomes from one DSB. DNA ends can either be directly ligated or, if the ends are incompatible, processed until a ligatable configuration is achieved that is often stabilized by up to 4 bp of terminal microhomology. Processing of DNA ends results in nucleotide loss or addition, explaining why DSBs repaired by NHEJ are rarely restored to their original DNA sequence. Thus, NHEJ is a single pathway with multiple enzymes at its disposal to repair DSBs, resulting in a diversity of repair outcomes.
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Affiliation(s)
- Nicholas R Pannunzio
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
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294
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Welty S, Teng Y, Liang Z, Zhao W, Sanders LH, Greenamyre JT, Rubio ME, Thathiah A, Kodali R, Wetzel R, Levine AS, Lan L. RAD52 is required for RNA-templated recombination repair in post-mitotic neurons. J Biol Chem 2017; 293:1353-1362. [PMID: 29217771 DOI: 10.1074/jbc.m117.808402] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/27/2017] [Indexed: 01/14/2023] Open
Abstract
It has been long assumed that post-mitotic neurons only utilize the error-prone non-homologous end-joining pathway to repair double-strand breaks (DSBs) associated with oxidative damage to DNA, given the inability of non-replicating neuronal DNA to utilize a sister chromatid template in the less error-prone homologous recombination (HR) repair pathway. However, we and others have found recently that active transcription triggers a replication-independent recombinational repair mechanism in G0/G1 phase of the cell cycle. Here we observed that the HR repair protein RAD52 is recruited to sites of DNA DSBs in terminally differentiated, post-mitotic neurons. This recruitment is dependent on the presence of a nascent mRNA generated during active transcription, providing evidence that an RNA-templated HR repair mechanism exists in non-dividing, terminally differentiated neurons. This recruitment of RAD52 in neurons is decreased by transcription inhibition. Importantly, we found that high concentrations of amyloid β, a toxic protein associated with Alzheimer's disease, inhibits the expression and DNA damage response of RAD52, potentially leading to a defect in the error-free, RNA-templated HR repair mechanism. This study shows a novel RNA-dependent repair mechanism of DSBs in post-mitotic neurons and demonstrates that defects in this pathway may contribute to neuronal genomic instability and consequent neurodegenerative phenotypes such as those seen in Alzheimer's disease.
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Affiliation(s)
- Starr Welty
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219.,the UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
| | - Yaqun Teng
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219.,the UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213.,the School of Medicine, Tsinghua University, No.1 Tsinghua Yuan, Haidian District, Beijing 100084, China
| | - Zhuobin Liang
- the Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, Connecticut 06520-8114
| | - Weixing Zhao
- the Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, Connecticut 06520-8114
| | - Laurie H Sanders
- the Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710
| | | | - Maria Eulalia Rubio
- the Department of Neurobiology and Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, and
| | | | - Ravindra Kodali
- the Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Ronald Wetzel
- Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Arthur S Levine
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219.,the UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
| | - Li Lan
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219, .,the UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
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295
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Zafar F, Okita AK, Onaka AT, Su J, Katahira Y, Nakayama JI, Takahashi TS, Masukata H, Nakagawa T. Regulation of mitotic recombination between DNA repeats in centromeres. Nucleic Acids Res 2017; 45:11222-11235. [PMID: 28977643 PMCID: PMC5737691 DOI: 10.1093/nar/gkx763] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
Centromeres that are essential for faithful segregation of chromosomes consist of unique DNA repeats in many eukaryotes. Although recombination is under-represented around centromeres during meiosis, little is known about recombination between centromere repeats in mitotic cells. Here, we compared spontaneous recombination that occurs between ade6B/ade6X inverted repeats integrated at centromere 1 (cen1) or at a non-centromeric ura4 locus in fission yeast. Remarkably, distinct mechanisms of homologous recombination (HR) were observed in centromere and non-centromere regions. Rad51-dependent HR that requires Rad51, Rad54 and Rad52 was predominant in the centromere, whereas Rad51-independent HR that requires Rad52 also occurred in the arm region. Crossovers between inverted repeats (i.e. inversions) were under-represented in the centromere as compared to the arm region. While heterochromatin was dispensable, Mhf1/CENP–S, Mhf2/CENP–X histone-fold proteins and Fml1/FANCM helicase were required to suppress crossovers. Furthermore, Mhf1 and Fml1 were found to prevent gross chromosomal rearrangements mediated by centromere repeats. These data uncovered the regulation of mitotic recombination between DNA repeats in centromeres and its physiological role in maintaining genome integrity.
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Affiliation(s)
- Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Akiko K Okita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yasuhiro Katahira
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 44-8585, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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296
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Human RAD52 Captures and Holds DNA Strands, Increases DNA Flexibility, and Prevents Melting of Duplex DNA: Implications for DNA Recombination. Cell Rep 2017; 18:2845-2853. [PMID: 28329678 PMCID: PMC5379009 DOI: 10.1016/j.celrep.2017.02.068] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/20/2017] [Accepted: 02/21/2017] [Indexed: 11/30/2022] Open
Abstract
Human RAD52 promotes annealing of complementary single-stranded DNA (ssDNA). In-depth knowledge of RAD52-DNA interaction is required to understand how its activity is integrated in DNA repair processes. Here, we visualize individual fluorescent RAD52 complexes interacting with single DNA molecules. The interaction with ssDNA is rapid, static, and tight, where ssDNA appears to wrap around RAD52 complexes that promote intra-molecular bridging. With double-stranded DNA (dsDNA), interaction is slower, weaker, and often diffusive. Interestingly, force spectroscopy experiments show that RAD52 alters the mechanics dsDNA by enhancing DNA flexibility and increasing DNA contour length, suggesting intercalation. RAD52 binding changes the nature of the overstretching transition of dsDNA and prevents DNA melting, which is advantageous for strand clamping during or after annealing. DNA-bound RAD52 is efficient at capturing ssDNA in trans. Together, these effects may help key steps in DNA repair, such as second-end capture during homologous recombination or strand annealing during RAD51-independent recombination reactions. RAD52 binds ssDNA rapidly and tightly using wrapping and bridging modes RAD52 binding to dsDNA is slower, weaker, and often diffusive RAD52 changes dsDNA mechanics and intercalates into the double helix RAD52 prevents DNA melting by clamping DNA strands
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297
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Han J, Ruan C, Huen MSY, Wang J, Xie A, Fu C, Liu T, Huang J. BRCA2 antagonizes classical and alternative nonhomologous end-joining to prevent gross genomic instability. Nat Commun 2017; 8:1470. [PMID: 29133916 PMCID: PMC5684403 DOI: 10.1038/s41467-017-01759-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/13/2017] [Indexed: 12/27/2022] Open
Abstract
BRCA2-deficient cells exhibit gross genomic instability, but the underlying mechanisms are not fully understood. Here we report that inactivation of BRCA2 but not RAD51 destabilizes RPA-coated single-stranded DNA (ssDNA) structures at resected DNA double-strand breaks (DSBs) and greatly enhances the frequency of nuclear fragmentation following cell exposure to DNA damage. Importantly, these BRCA2-associated deficits are fueled by the aberrant activation of classical (c)- and alternative (alt)- nonhomologous end-joining (NHEJ), and rely on the well-defined DNA damage signaling pathway involving the pro-c-NHEJ factor 53BP1 and its downstream effector RIF1. We further show that the 53BP1–RIF1 axis promotes toxic end-joining events via the retention of Artemis at DNA damage sites. Accordingly, loss of 53BP1, RIF1, or Artemis prolongs the stability of RPA-coated DSB intermediates in BRCA2-deficient cells and restores nuclear integrity. We propose that BRCA2 antagonizes 53BP1, RIF1, and Artemis-dependent c-NHEJ and alt-NHEJ to prevent gross genomic instability in a RAD51-independent manner. The genomic instability phenotype characteristic of BRCA2-deficient cells is not fully mechanistically understood. Here the authors show BRCA2 inactivation destabilizes RPA-coated single-stranded DNA and leads to toxic non homologous end-joining events.
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Affiliation(s)
- Jinhua Han
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Chunyan Ruan
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Michael S Y Huen
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Jiadong Wang
- Institute of Systems Biomedicine, Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Anyong Xie
- Institute of Translational Medicine, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Chun Fu
- Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ting Liu
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Jun Huang
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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298
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Ectopic expression of RAD52 and dn53BP1 improves homology-directed repair during CRISPR-Cas9 genome editing. Nat Biomed Eng 2017; 1:878-888. [PMID: 31015609 DOI: 10.1038/s41551-017-0145-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 09/13/2017] [Indexed: 12/17/2022]
Abstract
Gene disruption by clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) is highly efficient and relies on the error-prone non-homologous end-joining pathway. Conversely, precise gene editing requires homology-directed repair (HDR), which occurs at a lower frequency than non-homologous end-joining in mammalian cells. Here, by testing whether manipulation of DNA repair factors improves HDR efficacy, we show that transient ectopic co-expression of RAD52 and a dominant-negative form of tumour protein p53-binding protein 1 (dn53BP1) synergize to enable efficient HDR using a single-stranded oligonucleotide DNA donor template at multiple loci in human cells, including patient-derived induced pluripotent stem cells. Co-expression of RAD52 and dn53BP1 improves multiplexed HDR-mediated editing, whereas expression of RAD52 alone enhances HDR with Cas9 nickase. Our data show that the frequency of non-homologous end-joining-mediated double-strand break repair in the presence of these two factors is not suppressed and suggest that dn53BP1 competitively antagonizes 53BP1 to augment HDR in combination with RAD52. Importantly, co-expression of RAD52 and dn53BP1 does not alter Cas9 off-target activity. These findings support the use of RAD52 and dn53BP1 co-expression to overcome bottlenecks that limit HDR in precision genome editing.
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299
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Deniz M, Romashova T, Kostezka S, Faul A, Gundelach T, Moreno-Villanueva M, Janni W, Friedl TWP, Wiesmüller L. Increased single-strand annealing rather than non-homologous end-joining predicts hereditary ovarian carcinoma. Oncotarget 2017; 8:98660-98676. [PMID: 29228718 PMCID: PMC5716758 DOI: 10.18632/oncotarget.21720] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 08/26/2017] [Indexed: 12/22/2022] Open
Abstract
Mutations in genes encoding DNA double-strand break (DSB) repair components, especially homologous recombination (HR) proteins, were found to predispose to breast and ovarian cancer. Beyond high penetrance risk gene mutations underlying monogenic defects, low risk gene mutations generate polygenic defects, enlarging the fraction of individuals with a predisposing phenotype. DSB repair dysfunction opens new options for targeted therapies; poly (ADP-ribose) polymerase (PARP) inhibitors have been approved for BRCA-mutated and platinum-responsive ovarian cancers. In this work, we performed functional analyses in peripheral blood lymphocytes (PBLs) using a case-control design. We examined 38 women with familial history of breast and/or ovarian cancer, 40 women with primary ovarian cancer and 34 healthy controls. Using a GFP-based test we analyzed error-prone DSB repair mechanisms which are known to compensate for HR defects and to generate chromosomal instabilities. While non-homologous end-joining (NHEJ) did not discriminate between cases and controls, we found increases of single-strand annealing (SSA) in women with familial risk vs. controls (P=0.016) and patients with ovarian cancer vs. controls (P=0.002). Consistent with compromised HR we also detected increased sensitivities to carboplatin in PBLs from high-risk individuals (P<0.0001) as well as patients (P=0.0011) compared to controls. Conversely, neither PARP inhibitor responses nor PARP activities were altered in PBLs from the case groups, but PARP activities increased with age in high-risk individuals, providing novel clues for differential drug mode-of-action. Our findings indicate the great potential of detecting SSA activities to deliver an estimate of ovarian cancer susceptibility and therapeutic responsiveness beyond the limitations of genotyping.
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Affiliation(s)
- Miriam Deniz
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Tatiana Romashova
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Sarah Kostezka
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Anke Faul
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Theresa Gundelach
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | | | - Wolfgang Janni
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Thomas W P Friedl
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
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300
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PRPF8 is important for BRCA1-mediated homologous recombination. Oncotarget 2017; 8:93319-93337. [PMID: 29212152 PMCID: PMC5706798 DOI: 10.18632/oncotarget.21555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 09/15/2017] [Indexed: 11/25/2022] Open
Abstract
Disruption of RNA splicing causes genome instability, which could contribute to cancer etiology. Furthermore, RNA splicing is an emerging anti-cancer target. Thus, we have evaluated the influence of the spliceosome factor PRPF8 and the splicing inhibitor Pladienolide B (PlaB) on homologous recombination (HR). We find that PRPF8 depletion and PlaB treatment cause a specific defect in homology-directed repair (HDR), and single strand annealing (SSA), which share end resection as a common intermediate, and BRCA1 as a required factor. Furthermore, PRPF8 depletion and PlaB treatment cause reduced end resection detected as chromatin-bound RPA, BRCA1 foci in response to damage, and histone acetylation marks that are associated with BRCA1-mediated HR. We also identified distinctions between PlaB and PRPF8 depletion, in that PlaB also reduces 53BP1 foci, and BRCA1 expression. Furthermore loss of 53BP1, which rescues SSA in BRCA1 depleted cells, and partially rescues SSA in PRPF8 depleted cells, has no effect on SSA in PlaB treated cells. Finally, while PRPF8 depletion has no obvious effect on the integrity of interchromatin granules, PlaB disrupts these structures. These findings indicate that PRPF8 is important for BRCA1-mediated HR, whereas PlaB also has a more general effect on the DNA damage response and nuclear organization.
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