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Gao J, Gunasekar S, Xia ZJ, Shalin K, Jiang C, Chen H, Lee D, Lee S, Pisal ND, Luo JN, Griciuc A, Karp JM, Tanzi R, Joshi N. Gene therapy for CNS disorders: modalities, delivery and translational challenges. Nat Rev Neurosci 2024:10.1038/s41583-024-00829-7. [PMID: 38898231 DOI: 10.1038/s41583-024-00829-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/21/2024]
Abstract
Gene therapy is emerging as a powerful tool to modulate abnormal gene expression, a hallmark of most CNS disorders. The transformative potentials of recently approved gene therapies for the treatment of spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS) and active cerebral adrenoleukodystrophy are encouraging further development of this approach. However, most attempts to translate gene therapy to the clinic have failed to make it to market. There is an urgent need not only to tailor the genes that are targeted to the pathology of interest but to also address delivery challenges and thereby maximize the utility of genetic tools. In this Review, we provide an overview of gene therapy modalities for CNS diseases, emphasizing the interconnectedness of different delivery strategies and routes of administration. Important gaps in understanding that could accelerate the clinical translatability of CNS genetic interventions are addressed, and we present lessons learned from failed clinical trials that may guide the future development of gene therapies for the treatment and management of CNS disorders.
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Affiliation(s)
- Jingjing Gao
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA.
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, MA, USA.
| | - Swetharajan Gunasekar
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Ziting Judy Xia
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Kiruba Shalin
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA
| | - Christopher Jiang
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Hao Chen
- Marine College, Shandong University, Weihai, China
| | - Dongtak Lee
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Sohyung Lee
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Nishkal D Pisal
- Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA
| | - James N Luo
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Department of Surgery, Brigham and Women's Hospital, Boston, MA, USA
| | - Ana Griciuc
- Harvard Medical School, Boston, MA, USA.
- Genetics and Aging Research Unit, McCance Center for Brain Health, Mass General Institute for Neurodegenerative Disease and Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
| | - Jeffrey M Karp
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Harvard-MIT Program in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Rudolph Tanzi
- Harvard Medical School, Boston, MA, USA.
- Genetics and Aging Research Unit, McCance Center for Brain Health, Mass General Institute for Neurodegenerative Disease and Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
| | - Nitin Joshi
- Center for Nanomedicine, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
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Mojumdar A, Granger C, Lunke M, Cobb JA. Loss of Dna2 fidelity results in decreased Exo1-mediated resection at DNA double-strand breaks. J Biol Chem 2024; 300:105708. [PMID: 38311177 PMCID: PMC10909748 DOI: 10.1016/j.jbc.2024.105708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024] Open
Abstract
A DNA double-strand break (DSB) is one of the most dangerous types of DNA damage that is repaired largely by homologous recombination or nonhomologous end-joining (NHEJ). The interplay of repair factors at the break directs which pathway is used, and a subset of these factors also function in more mutagenic alternative (alt) repair pathways. Resection is a key event in repair pathway choice and extensive resection, which is a hallmark of homologous recombination, and it is mediated by two nucleases, Exo1 and Dna2. We observed differences in resection and repair outcomes in cells harboring nuclease-dead dna2-1 compared with dna2Δ pif1-m2 that could be attributed to the level of Exo1 recovered at DSBs. Cells harboring dna2-1 showed reduced Exo1 localization, increased NHEJ, and a greater resection defect compared with cells where DNA2 was deleted. Both the resection defect and the increased rate of NHEJ in dna2-1 mutants were reversed upon deletion of KU70 or ectopic expression of Exo1. By contrast, when DNA2 was deleted, Exo1 and Ku70 recovery levels did not change; however, Nej1 increased as did the frequency of alt-end joining/microhomology-mediated end-joining repair. Our findings demonstrate that decreased Exo1 at DSBs contributed to the resection defect in cells expressing inactive Dna2 and highlight the complexity of understanding how functionally redundant factors are regulated in vivo to promote genome stability.
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Affiliation(s)
- Aditya Mojumdar
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Courtney Granger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Martine Lunke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Jennifer A Cobb
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
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Li L, Vasan L, Kartono B, Clifford K, Attarpour A, Sharma R, Mandrozos M, Kim A, Zhao W, Belotserkovsky A, Verkuyl C, Schmitt-Ulms G. Advances in Recombinant Adeno-Associated Virus Vectors for Neurodegenerative Diseases. Biomedicines 2023; 11:2725. [PMID: 37893099 PMCID: PMC10603849 DOI: 10.3390/biomedicines11102725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors are gene therapy delivery tools that offer a promising platform for the treatment of neurodegenerative diseases. Keeping up with developments in this fast-moving area of research is a challenge. This review was thus written with the intention to introduce this field of study to those who are new to it and direct others who are struggling to stay abreast of the literature towards notable recent studies. In ten sections, we briefly highlight early milestones within this field and its first clinical success stories. We showcase current clinical trials, which focus on gene replacement, gene augmentation, or gene suppression strategies. Next, we discuss ongoing efforts to improve the tropism of rAAV vectors for brain applications and introduce pre-clinical research directed toward harnessing rAAV vectors for gene editing applications. Subsequently, we present common genetic elements coded by the single-stranded DNA of rAAV vectors, their so-called payloads. Our focus is on recent advances that are bound to increase treatment efficacies. As needed, we included studies outside the neurodegenerative disease field that showcased improved pre-clinical designs of all-in-one rAAV vectors for gene editing applications. Finally, we discuss risks associated with off-target effects and inadvertent immunogenicity that these technologies harbor as well as the mitigation strategies available to date to make their application safer.
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Affiliation(s)
- Leyao Li
- Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
| | - Lakshmy Vasan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Bryan Kartono
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Kevan Clifford
- Institute of Medical Science, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
- Centre for Addiction and Mental Health (CAMH), 250 College St., Toronto, ON M5T 1R8, Canada
| | - Ahmadreza Attarpour
- Department of Medical Biophysics, University of Toronto, 101 College St., Toronto, ON M5G 1L7, Canada
| | - Raghav Sharma
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Matthew Mandrozos
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Ain Kim
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Wenda Zhao
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Ari Belotserkovsky
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Claire Verkuyl
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
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Gan X, Zhang Y, Jiang D, Shi J, Zhao H, Xie C, Wang Y, Xu J, Zhang X, Cai G, Wang H, Huang J, Chen X. Proper RPA acetylation promotes accurate DNA replication and repair. Nucleic Acids Res 2023; 51:5565-5583. [PMID: 37140030 PMCID: PMC10287905 DOI: 10.1093/nar/gkad291] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 05/05/2023] Open
Abstract
The single-stranded DNA (ssDNA) binding protein complex RPA plays a critical role in promoting DNA replication and multiple DNA repair pathways. However, how RPA is regulated to achieve its functions precisely in these processes remains elusive. Here, we found that proper acetylation and deacetylation of RPA are required to regulate RPA function in promoting high-fidelity DNA replication and repair. We show that yeast RPA is acetylated on multiple conserved lysines by the acetyltransferase NuA4 upon DNA damage. Mimicking constitutive RPA acetylation or blocking its acetylation causes spontaneous mutations with the signature of micro-homology-mediated large deletions or insertions. In parallel, improper RPA acetylation/deacetylation impairs DNA double-strand break (DSB) repair by the accurate gene conversion or break-induced replication while increasing the error-prone repair by single-strand annealing or alternative end joining. Mechanistically, we show that proper acetylation and deacetylation of RPA ensure its normal nuclear localization and ssDNA binding ability. Importantly, mutation of the equivalent residues in human RPA1 also impairs RPA binding on ssDNA, leading to attenuated RAD51 loading and homologous recombination repair. Thus, timely RPA acetylation and deacetylation likely represent a conserved mechanism promoting high-fidelity replication and repair while discriminating the error-prone repair mechanisms in eukaryotes.
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Affiliation(s)
- Xiaoli Gan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Yueyue Zhang
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Donghao Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Jingyao Shi
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Han Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Chengyu Xie
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Yanyan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Jingyan Xu
- Department of Hematology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Xinghua Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
| | - Gang Cai
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Jun Huang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Centre of Immunology and Metabolism, Wuhan University, Wuhan, Hubei 430072, China
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DNA double-strand break repair machinery in Penaeid crustaceans: A focus on the Non-Homologous End-Joining pathway. Comp Biochem Physiol B Biochem Mol Biol 2023; 264:110803. [DOI: 10.1016/j.cbpb.2022.110803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/12/2022]
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The remodeling of Z-DNA in the mammalian germ line. Biochem Soc Trans 2022; 50:1875-1884. [PMID: 36454621 PMCID: PMC9788570 DOI: 10.1042/bst20221015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 12/02/2022]
Abstract
We recently discovered a novel biological process, the scheduled remodeling of Z-DNA structures in the developing fetal mouse male germ cells [Nat. Cell Biol. 24, 1141-1153]. This process affects purine/pyrimidine dinucleotide repeat (PPR) rich sequences, which can form stable left-handed Z-DNA structures. The protein that carries out this function is identified as ZBTB43, member of a large family of ZBTB proteins. Z-DNA remodeling by ZBTB43 not only coincides with global remodeling of DNA methylation and chromatin events in the male germ line, but it also is a prerequisite for de novo DNA methylation. When ZBTB43 changes DNA structure from the left-handed zigzag shaped Z-DNA to the regular smooth right-handed B-DNA, it also generates a suitable substrate for the de novo DNA methyltransferase, DNMT3A. By instructing de novo DNA methylation at PPRs in prospermatogonia, ZBTB43 safeguards epigenomic integrity of the male gamete. PPRs are fragile sequences, sites of large deletions and rearrangements in mammalian cells, and this fragility is thought to be due to Z-DNA structure formation rather than the sequence itself. This idea is now supported by the in vivo finding that DNA double strand breaks accumulate in mutant prospermatogonia which lack ZBTB43-dependent Z-DNA remodeling. If unrepaired, double stranded DNA breaks can lead to germ line mutations. Therefore, by preventing such breaks ZBTB43 is critical for guarding genome stability between generations. Here, we discuss the significance and implications of these findings in more detail.
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Mojumdar A, Mair N, Adam N, Cobb JA. Changes in DNA double-strand break repair during aging correlate with an increase in genomic mutations. J Mol Biol 2022; 434:167798. [PMID: 35998703 DOI: 10.1016/j.jmb.2022.167798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/24/2022]
Abstract
A double -strand break (DSB) is one of the most deleterious forms of DNA damage. In eukaryotic cells, two main repair pathways have evolved to repair DSBs, homologous recombination (HR) and non-homologous end-joining (NHEJ). HR is the predominant pathway of repair in the unicellular eukaryotic organism, S. cerevisiae. However, during replicative aging the relative use of HR and NHEJ shifts in favor of end-joining repair. By monitoring repair events in the HO-DSB system, we find that early in replicative aging there is a decrease in the association of long-range resection factors, Dna2-Sgs1 and Exo1 at the break site and a decrease in DNA resection. Subsequently, as aging progressed, the recovery of Ku70 at DSBs decreased and the break site associated with the nuclear pore complex at the nuclear periphery, which is the location where DSB repair occurs through alternative pathways that are more mutagenic. End-bridging remained intact as HR and NHEJ declined, but eventually it too became disrupted in cells at advanced replicative age. In all, our work provides insight into the molecular changes in DSB repair pathway during replicative aging. HR first declined, resulting in a transient increase in the NHEJ. However, with increased cellular divisions, Ku70 recovery at DSBs and NHEJ subsequently declined. In wild type cells of advanced replicative age, there was a high frequency of repair products with genomic deletions and microhomologies at the break junction, events not observed in young cells which repaired primarily by HR.
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Affiliation(s)
- Aditya Mojumdar
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Nicola Mair
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Nancy Adam
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jennifer A Cobb
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
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Shams F, Bayat H, Mohammadian O, Mahboudi S, Vahidnezhad H, Soosanabadi M, Rahimpour A. Advance trends in targeting homology-directed repair for accurate gene editing: An inclusive review of small molecules and modified CRISPR-Cas9 systems. BIOIMPACTS 2022; 12:371-391. [PMID: 35975201 PMCID: PMC9376165 DOI: 10.34172/bi.2022.23871] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/21/2021] [Accepted: 11/21/2021] [Indexed: 11/25/2022]
Abstract
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Introduction: Clustered regularly interspaced short palindromic repeat and its associated protein (CRISPR-Cas)-based technologies generate targeted modifications in host genome by inducing site-specific double-strand breaks (DSBs) that can serve as a substrate for homology-directed repair (HDR) in both in vitro and in vivo models. HDR pathway could enhance incorporation of exogenous DNA templates into the CRISPR-Cas9-mediated DSB site. Owing to low rate of HDR pathway, the efficiency of accurate genome editing is diminished. Enhancing the efficiency of HDR can provide fast, easy, and accurate technologies based on CRISPR-Cas9 technologies.
Methods: The current study presents an overview of attempts conducted on the precise genome editing strategies based on small molecules and modified CRISPR-Cas9 systems.
Results: In order to increase HDR rate in targeted cells, several logical strategies have been introduced such as generating CRISPR effector chimeric proteins, anti-CRISPR proteins, modified Cas9 with donor template, and using validated synthetic or natural small molecules for either inhibiting non-homologous end joining (NHEJ), stimulating HDR, or synchronizing cell cycle. Recently, high-throughput screening methods have been applied for identification of small molecules which along with the CRISPR system can regulate precise genome editing through HDR.
Conclusion: The stimulation of HDR components or inhibiting NHEJ can increase the accuracy of CRISPR-Cas-mediated engineering systems. Generating chimeric programmable endonucleases provide this opportunity to direct DNA template close proximity of CRISPR-Cas-mediated DSB. Small molecules and their derivatives can also proficiently block or activate certain DNA repair pathways and bring up novel perspectives for increasing HDR efficiency, especially in human cells. Further, high throughput screening of small molecule libraries could result in more discoveries of promising chemicals that improve HDR efficiency and CRISPR-Cas9 systems.
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Affiliation(s)
- Forough Shams
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hadi Bayat
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omid Mohammadian
- Medical Nano-Technology and Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Somayeh Mahboudi
- Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Mohsen Soosanabadi
- Department of Medical Genetics, Semnan University of Medical Sciences, Semnan, Iran
| | - Azam Rahimpour
- Medical Nano-Technology and Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Kyo S, Kanno K, Takakura M, Yamashita H, Ishikawa M, Ishibashi T, Sato S, Nakayama K. Clinical Landscape of PARP Inhibitors in Ovarian Cancer: Molecular Mechanisms and Clues to Overcome Resistance. Cancers (Basel) 2022; 14:cancers14102504. [PMID: 35626108 PMCID: PMC9139943 DOI: 10.3390/cancers14102504] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Recent development of maintenance therapy using PARP inhibitors in ovarian cancer has led to a significant improvement in survival rates. However, resistance to these inhibitors can occur in patients, causing disease progression or relapse. Consequently, novel treatment strategies are urgently needed to overcome this resistance. This review article focuses on the precise molecular mechanisms by which PARP inhibitors exert their antitumor effects, as well as how they elicit resistance, in order to gain insight into novel therapeutic approaches to overcome PARP inhibitor resistance in ovarian cancer. Abstract The survival of patients with advanced or recurrent ovarian cancer has improved tremendously in the past decade, mainly due to the establishment of maintenance therapy with poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) after conservative chemotherapies. Despite their superior efficacy, resistance to PARPis has been reported, and patients with resistance have a much worse prognosis. Therefore, the development of novel treatment strategies to overcome PARPi resistance is urgently needed. The present review article focuses on the molecular mechanisms of how PARPis exert cytotoxic effects on cancer cells through DNA repair processes, especially the genetic background and tumor microenvironment favored by PARPis. Furthermore, currently available information on PARPi resistance mechanisms is introduced and discussed to develop a novel therapeutic approach against them.
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Affiliation(s)
- Satoru Kyo
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
- Correspondence: ; Fax: +81-(0)853-20-2264
| | - Kosuke Kanno
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
| | - Masahiro Takakura
- Department of Obstetrics and Gynecology, Kanazawa Medical University, Kanazawa 920-0293, Japan;
| | - Hitomi Yamashita
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
| | - Masako Ishikawa
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
| | - Tomoka Ishibashi
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
| | - Seiya Sato
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
| | - Kentaro Nakayama
- Department of Obstetrics and Gynecology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (K.K.); (H.Y.); (M.I.); (T.I.); (S.S.); (K.N.)
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10
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Kitamura S, Satoh K, Oono Y. Detection and characterization of genome-wide mutations in M1 vegetative cells of gamma-irradiated Arabidopsis. PLoS Genet 2022; 18:e1009979. [PMID: 35051177 PMCID: PMC8775353 DOI: 10.1371/journal.pgen.1009979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/04/2021] [Indexed: 11/20/2022] Open
Abstract
Radiation-induced mutations have been detected by whole-genome sequencing analyses of self-pollinated generations of mutagenized plants. However, large DNA alterations and mutations in non-germline cells were likely missed. In this study, in order to detect various types of mutations in mutagenized M1 plants, anthocyanin pigmentation was used as a visible marker of mutations. Arabidopsis seeds heterozygous for the anthocyanin biosynthetic genes were irradiated with gamma-rays. Anthocyanin-less vegetative sectors resulting from a loss of heterozygosity were isolated from the gamma-irradiated M1 plants. The whole-genome sequencing analysis of the sectors detected various mutations, including structural variations (SVs) and large deletions (≥100 bp), both of which have been less characterized in the previous researches using gamma-irradiated plant genomes of M2 or later generations. Various types of rejoined sites were found in SVs, including no-insertion/deletion (indel) sites, only-deletion sites, only-insertion sites, and indel sites, but the rejoined sites with 0–5 bp indels represented most of the SVs. Examinations of the junctions of rearrangements (SVs and large deletions), medium deletions (10–99 bp), and small deletions (2–9 bp) revealed unique features (i.e., frequency of insertions and microhomology) at the rejoined sites. These results suggest that they were formed preferentially via different processes. Additionally, mutations that occurred in putative single M1 cells were identified according to the distribution of their allele frequency. The estimated mutation frequencies and spectra of the M1 cells were similar to those of previously analyzed M2 cells, with the exception of the greater proportion of rearrangements in the M1 cells. These findings suggest there are no major differences in the small mutations (<100 bp) between vegetative and germline cells. Thus, this study generated valuable information that may help clarify the nature of gamma-irradiation-induced mutations and their occurrence in cells that develop into vegetative or reproductive tissues. Mutations that occur in plant genome are not only related to plant evolution and speciation in nature, and also useful to identify novel gene functions and to develop new cultivars. Ionizing radiations induce various types of mutations throughout genomes in individual cells of an irradiated/mutagenized plant. However, current knowledge on radiation-induced genome-wide mutations in plants relied on the analyses of self-pollinated generations (M2 or later generations) of the mutagenized plants (M1 generation). Thus, mutations that are hardly transmitted to the next generation and those occurred in non-germline cells could not be investigated. Here, using anthocyanin pigmentation as a visible marker to reduce the genomic complexity in M1 plants, we achieved reliable detection of radiation-induced genome-wide mutations. We demonstrated that rearrangements, which were hardly detected in previous analyses using M2 genomes, occurred substantially often in gamma-irradiated M1 cells. We also revealed that mutation profile of the M1 cells was comparable with that of M2 genomes reported in previous analyses, except for the higher proportion of rearrangements in the M1 genome. Together with unique features at rejoined sites of rearrangements, medium deletions, and small deletions in the M1 genome, our findings are helpful to know the nature of genome-wide mutations induced by gamma-irradiation.
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Affiliation(s)
- Satoshi Kitamura
- Project “Ion Beam Mutagenesis”, Department of Radiation-Applied Biology Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology, Takasaki, Japan
- * E-mail:
| | - Katsuya Satoh
- Project “Ion Beam Mutagenesis”, Department of Radiation-Applied Biology Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology, Takasaki, Japan
| | - Yutaka Oono
- Project “Ion Beam Mutagenesis”, Department of Radiation-Applied Biology Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology, Takasaki, Japan
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11
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Song D, Li X, Wei W, Liu X, Wu L, Xiong H. Microhomology-Mediated Nonhomologous End Joining Caused Rearrangement of EMD and FLNA in Emery-Dreifuss Muscular Dystrophy. Front Genet 2022; 12:786294. [PMID: 34976019 PMCID: PMC8719250 DOI: 10.3389/fgene.2021.786294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/15/2021] [Indexed: 12/01/2022] Open
Abstract
Background: Emery–Dreifuss muscular dystrophy (EDMD) is a rare disease characterized by early joint contractures, slowly progressive muscular dystrophy, and cardiac involvement, which includes arrhythmia, dilated cardiomyopathy, hypertrophic cardiomyopathy, heart failure, and sudden death. Methods: Clinical data of the proband and family members were collected. The next-generation sequencing technology was used to analyze the pathogenic variants and copy number variations. Polymerase chain reaction was used to sequence the breakpoints of gene locus rearrangements. Results: Here, we report two siblings with EDMD in a family. The proband, a 17-year-old boy, manifested a dilated right heart, bradycardia, mild muscle weakness, and joint contractures. His younger brother only showed a mild bowing limitation with elevated creatine kinase. Next-generation sequencing revealed the complete deletion of EMD and a rearrangement in FLNA (exon29_48dup) in these two patients. The EMD deletion and partial FLNA duplication were accompanied by a 5 bp overlap (GTCCC) on the background of the FLNA-EMD inversion. These findings support the pathogenic mechanism of microhomology-mediated nonhomologous end joining. Conclusion: We report two siblings with complete EMD deletion and FLNA duplication in a family. A microhomology-mediated nonhomologous end joining event involving EMD and FLNA acts as the underlying mechanism.
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Affiliation(s)
- Danyu Song
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaomei Li
- Department of Pediatric Cardiology, The First Hospital of Tsinghua University (Beijing Huaxin Hospital), Beijing, China
| | - Wei Wei
- Beijing Kangso Medical Inspection Co., Ltd., Beijing, China
| | - Xueqin Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Lin Wu
- Department of Cardiology, Peking University First Hospital, Beijing, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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12
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Paulsen T, Malapati P, Shibata Y, Wilson B, Eki R, Benamar M, Abbas T, Dutta A. MicroDNA levels are dependent on MMEJ, repressed by c-NHEJ pathway, and stimulated by DNA damage. Nucleic Acids Res 2021; 49:11787-11799. [PMID: 34718766 PMCID: PMC8599734 DOI: 10.1093/nar/gkab984] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 12/23/2022] Open
Abstract
Extrachromosomal circular DNA (eccDNA) are present within all eukaryotic organisms and actively contribute to gene expression changes. MicroDNA (200-1000bp) are the most abundant type of eccDNA and can amplify tRNA, microRNA, and novel si-like RNA sequences. Due to the heterogeneity of microDNA and the limited technology to directly quantify circular DNA molecules, the specific DNA repair pathways that contribute to microDNA formation have not been fully elucidated. Using a sensitive and quantitative assay that quantifies eight known abundant microDNA, we report that microDNA levels are dependent on resection after double-strand DNA break (DSB) and repair by Microhomology Mediated End Joining (MMEJ). Further, repair of DSB without resection by canonical Non-Homologous End Joining (c-NHEJ) diminishes microDNA formation. MicroDNA levels are induced locally even by a single site-directed DSB, suggesting that excision of genomic DNA by two closely spaced DSB is not necessary for microDNA formation. Consistent with all this, microDNA levels accumulate as cells undergo replication in S-phase, when DNA breaks and repair are elevated, and microDNA levels are decreased if DNA synthesis is prevented. Thus, formation of microDNA occurs during the repair of endogenous or induced DNA breaks by resection-based DNA repair pathways.
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Affiliation(s)
- Teressa Paulsen
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Pumoli Malapati
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yoshiyuki Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
| | - Briana Wilson
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Rebeka Eki
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mouadh Benamar
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Tarek Abbas
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.,Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
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13
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Tomasini PP, Guecheva TN, Leguisamo NM, Péricart S, Brunac AC, Hoffmann JS, Saffi J. Analyzing the Opportunities to Target DNA Double-Strand Breaks Repair and Replicative Stress Responses to Improve Therapeutic Index of Colorectal Cancer. Cancers (Basel) 2021; 13:3130. [PMID: 34201502 PMCID: PMC8268241 DOI: 10.3390/cancers13133130] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 12/22/2022] Open
Abstract
Despite the ample improvements of CRC molecular landscape, the therapeutic options still rely on conventional chemotherapy-based regimens for early disease, and few targeted agents are recommended for clinical use in the metastatic setting. Moreover, the impact of cytotoxic, targeted agents, and immunotherapy combinations in the metastatic scenario is not fully satisfactory, especially the outcomes for patients who develop resistance to these treatments need to be improved. Here, we examine the opportunity to consider therapeutic agents targeting DNA repair and DNA replication stress response as strategies to exploit genetic or functional defects in the DNA damage response (DDR) pathways through synthetic lethal mechanisms, still not explored in CRC. These include the multiple actors involved in the repair of DNA double-strand breaks (DSBs) through homologous recombination (HR), classical non-homologous end joining (NHEJ), and microhomology-mediated end-joining (MMEJ), inhibitors of the base excision repair (BER) protein poly (ADP-ribose) polymerase (PARP), as well as inhibitors of the DNA damage kinases ataxia-telangiectasia and Rad3 related (ATR), CHK1, WEE1, and ataxia-telangiectasia mutated (ATM). We also review the biomarkers that guide the use of these agents, and current clinical trials with targeted DDR therapies.
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Affiliation(s)
- Paula Pellenz Tomasini
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
| | - Temenouga Nikolova Guecheva
- Cardiology Institute of Rio Grande do Sul, University Foundation of Cardiology (IC-FUC), Porto Alegre 90620-000, Brazil;
| | - Natalia Motta Leguisamo
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
| | - Sarah Péricart
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Anne-Cécile Brunac
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jean Sébastien Hoffmann
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jenifer Saffi
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
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14
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Rtt105 promotes high-fidelity DNA replication and repair by regulating the single-stranded DNA-binding factor RPA. Proc Natl Acad Sci U S A 2021; 118:2106393118. [PMID: 34140406 DOI: 10.1073/pnas.2106393118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Single-stranded DNA (ssDNA) covered with the heterotrimeric Replication Protein A (RPA) complex is a central intermediate of DNA replication and repair. How RPA is regulated to ensure the fidelity of DNA replication and repair remains poorly understood. Yeast Rtt105 is an RPA-interacting protein required for RPA nuclear import and efficient ssDNA binding. Here, we describe an important role of Rtt105 in high-fidelity DNA replication and recombination and demonstrate that these functions of Rtt105 primarily depend on its regulation of RPA. The deletion of RTT105 causes elevated spontaneous DNA mutations with large duplications or deletions mediated by microhomologies. Rtt105 is recruited to DNA double-stranded break (DSB) ends where it promotes RPA assembly and homologous recombination repair by gene conversion or break-induced replication. In contrast, Rtt105 attenuates DSB repair by the mutagenic single-strand annealing or alternative end joining pathway. Thus, Rtt105-mediated regulation of RPA promotes high-fidelity replication and recombination while suppressing repair by deleterious pathways. Finally, we show that the human RPA-interacting protein hRIP-α, a putative functional homolog of Rtt105, also stimulates RPA assembly on ssDNA, suggesting the conservation of an Rtt105-mediated mechanism.
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15
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Halliwell JA, Baker D, Judge K, Quail MA, Oliver K, Betteridge E, Skelton J, Andrews PW, Barbaric I. Nanopore Sequencing Indicates That Tandem Amplification of Chromosome 20q11.21 in Human Pluripotent Stem Cells Is Driven by Break-Induced Replication. Stem Cells Dev 2021; 30:578-586. [PMID: 33757297 PMCID: PMC8165465 DOI: 10.1089/scd.2021.0013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Copy number variants (CNVs) are genomic rearrangements implicated in numerous congenital and acquired diseases, including cancer. The appearance of culture-acquired CNVs in human pluripotent stem cells (PSCs) has prompted concerns for their use in regenerative medicine. A particular problem in PSC is the frequent occurrence of CNVs in the q11.21 region of chromosome 20. However, the exact mechanism of origin of this amplicon remains elusive due to the difficulty in delineating its sequence and breakpoints. Here, we have addressed this problem using long-read Nanopore sequencing of two examples of this CNV, present as duplication and as triplication. In both cases, the CNVs were arranged in a head-to-tail orientation, with microhomology sequences flanking or overlapping the proximal and distal breakpoints. These breakpoint signatures point to a mechanism of microhomology-mediated break-induced replication in CNV formation, with surrounding Alu sequences likely contributing to the instability of this genomic region.
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Affiliation(s)
- Jason A Halliwell
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Duncan Baker
- Sheffield Diagnostic Genetic Services, Sheffield Children's Hospital, Sheffield, United Kingdom
| | - Kim Judge
- Department of Sequencing R & D, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Michael A Quail
- Department of Sequencing R & D, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Karen Oliver
- Department of Sequencing R & D, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Emma Betteridge
- Department of Sequencing R & D, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Jason Skelton
- Department of Sequencing R & D, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Peter W Andrews
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Ivana Barbaric
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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16
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Pócza T, Grolmusz VK, Papp J, Butz H, Patócs A, Bozsik A. Germline Structural Variations in Cancer Predisposition Genes. Front Genet 2021; 12:634217. [PMID: 33936164 PMCID: PMC8081352 DOI: 10.3389/fgene.2021.634217] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/08/2021] [Indexed: 12/14/2022] Open
Abstract
In addition to single nucleotide variations and small-scale indels, structural variations (SVs) also contribute to the genetic diversity of the genome. SVs, such as deletions, duplications, amplifications, or inversions may also affect coding regions of cancer-predisposing genes. These rearrangements may abrogate the open reading frame of these genes or adversely affect their expression and may thus act as germline mutations in hereditary cancer syndromes. With the capacity of disrupting the function of tumor suppressors, structural variations confer an increased risk of cancer and account for a remarkable fraction of heritability. The development of sequencing techniques enables the discovery of a constantly growing number of SVs of various types in cancer predisposition genes (CPGs). Here, we provide a comprehensive review of the landscape of germline SV types, detection methods, pathomechanisms, and frequency in CPGs, focusing on the two most common cancer syndromes: hereditary breast- and ovarian cancer and gastrointestinal cancers. Current knowledge about the possible molecular mechanisms driving to SVs is also summarized.
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Affiliation(s)
- Tímea Pócza
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary
| | - Vince Kornél Grolmusz
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - János Papp
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - Henriett Butz
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary.,Department of Laboratory Medicine, Semmelweis University, Budapest, Hungary
| | - Attila Patócs
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary.,Department of Laboratory Medicine, Semmelweis University, Budapest, Hungary
| | - Anikó Bozsik
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
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17
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Ghosh D, Raghavan SC. Nonhomologous end joining: new accessory factors fine tune the machinery. Trends Genet 2021; 37:582-599. [PMID: 33785198 DOI: 10.1016/j.tig.2021.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/08/2023]
Abstract
Nonhomologous DNA end joining (NHEJ) is one of the major DNA double-strand break (DSB) repair pathways in eukaryotes. The well-known critical proteins involved in NHEJ include Ku70/80, DNA-PKcs, Artemis, DNA pol λ/μ, DNA ligase IV-XRCC4, and XLF. Recent studies have added a number of new proteins to the NHEJ repertoire namely paralog of XRCC4 and XLF (PAXX), modulator of retroviral infection (MRI)/ cell cycle regulator of NHEJ (CYREN), transactivation response DNA-binding protein (TARDBP) of 43 kDa (TDP-43), intermediate filament family orphan (IFFO1), ERCC excision repair 6 like 2 (ERCC6L2), and RNase H2. PAXX acts as a stabilizing factor for the main NHEJ components. MRI/CYREN seems to play a dual role stimulating NHEJ in the G1 phase of the cell cycle, while inhibiting the pathway in the S and G2 phases. TDP-43 can recruit the ligase IV-XRCC4 complex to the DSB sites and stimulate ligation in neuronal cells. RNase H2 excises out the ribonucleotides inserted during repair by DNA polymerase μ/TdT. This review provides a brief glimpse into how these new partners were discovered and their contribution to the mechanism and regulation of NHEJ.
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Affiliation(s)
- Dipayan Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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18
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Pérez-Arnaiz P, Dattani A, Smith V, Allers T. Haloferax volcanii-a model archaeon for studying DNA replication and repair. Open Biol 2020; 10:200293. [PMID: 33259746 PMCID: PMC7776575 DOI: 10.1098/rsob.200293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
The tree of life shows the relationship between all organisms based on their common ancestry. Until 1977, it comprised two major branches: prokaryotes and eukaryotes. Work by Carl Woese and other microbiologists led to the recategorization of prokaryotes and the proposal of three primary domains: Eukarya, Bacteria and Archaea. Microbiological, genetic and biochemical techniques were then needed to study the third domain of life. Haloferax volcanii, a halophilic species belonging to the phylum Euryarchaeota, has provided many useful tools to study Archaea, including easy culturing methods, genetic manipulation and phenotypic screening. This review will focus on DNA replication and DNA repair pathways in H. volcanii, how this work has advanced our knowledge of archaeal cellular biology, and how it may deepen our understanding of bacterial and eukaryotic processes.
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Affiliation(s)
| | | | | | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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19
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Pettitt SJ, Frankum JR, Punta M, Lise S, Alexander J, Chen Y, Yap TA, Haider S, Tutt ANJ, Lord CJ. Clinical BRCA1/2 Reversion Analysis Identifies Hotspot Mutations and Predicted Neoantigens Associated with Therapy Resistance. Cancer Discov 2020; 10:1475-1488. [PMID: 32699032 PMCID: PMC7611203 DOI: 10.1158/2159-8290.cd-19-1485] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/16/2020] [Accepted: 07/01/2020] [Indexed: 02/06/2023]
Abstract
Reversion mutations in BRCA1 or BRCA2 are associated with resistance to PARP inhibitors and platinum. To better understand the nature of these mutations, we collated, codified, and analyzed more than 300 reversions. This identified reversion "hotspots" and "deserts" in regions encoding the N and C terminus, respectively, of BRCA2, suggesting that pathogenic mutations in these regions may be at higher or lower risk of reversion. Missense and splice-site pathogenic mutations in BRCA1/2 also appeared less likely to revert than truncating mutations. Most reversions were <100 bp deletions. Although many deletions exhibited microhomology, this was not universal, suggesting that multiple DNA-repair processes cause reversion. Finally, we found that many reversions were predicted to encode immunogenic neopeptides, suggesting a route to the treatment of reverted disease. As well as providing a freely available database for the collation of future reversion cases, these observations have implications for how drug resistance might be managed in BRCA-mutant cancers. SIGNIFICANCE: Reversion mutations in BRCA genes are a major cause of clinical platinum and PARP inhibitor resistance. This analysis of all reported clinical reversions suggests that the position of BRCA2 mutations affects the risk of reversion. Many reversions are also predicted to encode tumor neoantigens, providing a potential route to targeting resistance.This article is highlighted in the In This Issue feature, p. 1426.
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Affiliation(s)
- Stephen J Pettitt
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Jessica R Frankum
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Marco Punta
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, United Kingdom
| | - Stefano Lise
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, United Kingdom
| | - John Alexander
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Yi Chen
- Scientific Computing Team, The Institute of Cancer Research, London, United Kingdom
| | - Timothy A Yap
- The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Syed Haider
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Andrew N J Tutt
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Christopher J Lord
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
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20
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Complex Characterization of Germline Large Genomic Rearrangements of the BRCA1 and BRCA2 Genes in High-Risk Breast Cancer Patients-Novel Variants from a Large National Center. Int J Mol Sci 2020; 21:ijms21134650. [PMID: 32629901 PMCID: PMC7370166 DOI: 10.3390/ijms21134650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/19/2020] [Accepted: 06/27/2020] [Indexed: 12/23/2022] Open
Abstract
Large genomic rearrangements (LGRs) affecting one or more exons of BRCA1 and BRCA2 constitute a significant part of the mutation spectrum of these genes. Since 2004, the National Institute of Oncology, Hungary, has been involved in screening for LGRs of breast or ovarian cancer families enrolled for genetic testing. LGRs were detected by multiplex ligation probe amplification method, or next-generation sequencing. Where it was possible, transcript-level characterization of LGRs was performed. Phenotype data were collected and analyzed too. Altogether 28 different types of LGRs in 51 probands were detected. Sixteen LGRs were novel. Forty-nine cases were deletions or duplications in BRCA1 and two affected BRCA2. Rearrangements accounted for 10% of the BRCA1 mutations. Three exon copy gains, two complex rearrangements, and 23 exon losses were characterized by exact breakpoint determinations. The inferred mechanisms for LGR formation were mainly end-joining repairs utilizing short direct homologies. Comparing phenotype features of the LGR-carriers to that of the non-LGR BRCA1 mutation carriers, revealed no significant differences. Our study is the largest comprehensive report of LGRs of BRCA1/2 in familial breast and ovarian cancer patients in the Middle and Eastern European region. Our data add novel insights to genetic interpretation associated to the LGRs.
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21
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Daley JM, Tomimatsu N, Hooks G, Wang W, Miller AS, Xue X, Nguyen KA, Kaur H, Williamson E, Mukherjee B, Hromas R, Burma S, Sung P. Specificity of end resection pathways for double-strand break regions containing ribonucleotides and base lesions. Nat Commun 2020; 11:3088. [PMID: 32555206 PMCID: PMC7303207 DOI: 10.1038/s41467-020-16903-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 05/29/2020] [Indexed: 12/19/2022] Open
Abstract
DNA double-strand break repair by homologous recombination begins with nucleolytic resection of the 5’ DNA strand at the break ends. Long-range resection is catalyzed by EXO1 and BLM-DNA2, which likely have to navigate through ribonucleotides and damaged bases. Here, we show that a short stretch of ribonucleotides at the 5’ terminus stimulates resection by EXO1. Ribonucleotides within a 5’ flap are resistant to cleavage by DNA2, and extended RNA:DNA hybrids inhibit both strand separation by BLM and resection by EXO1. Moreover, 8-oxo-guanine impedes EXO1 but enhances resection by BLM-DNA2, and an apurinic/apyrimidinic site stimulates resection by BLM-DNA2 and DNA strand unwinding by BLM. Accordingly, depletion of OGG1 or APE1 leads to greater dependence of DNA resection on DNA2. Importantly, RNase H2A deficiency impairs resection overall, which we attribute to the accumulation of long RNA:DNA hybrids at DNA ends. Our results help explain why eukaryotic cells possess multiple resection nucleases. DNA double-strand break repair by homologous recombination initiates with nucleolytic resection of the 5’ DNA strand at the break ends. Here, the authors reveal that the lesion context influences the action and efficiency of the long range resection factors EXO1 and BLM-DNA2.
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Affiliation(s)
- James M Daley
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA. .,Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
| | - Nozomi Tomimatsu
- Department of Neurosurgery, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Grace Hooks
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA.,Department of Biochemistry, Duke University, Durham, NC, 27710, USA
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA.,Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Adam S Miller
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA.,Regeneron, Rensselaer, NY, 12144, USA
| | - Xiaoyu Xue
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA.,Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX, USA
| | - Kevin A Nguyen
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA.,David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Hardeep Kaur
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Elizabeth Williamson
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Bipasha Mukherjee
- Department of Neurosurgery, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Robert Hromas
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Sandeep Burma
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA. .,Department of Neurosurgery, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, 06510, USA. .,Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
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22
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Schotanus K, Heitman J. Centromere deletion in Cryptococcus deuterogattii leads to neocentromere formation and chromosome fusions. eLife 2020; 9:56026. [PMID: 32310085 PMCID: PMC7188483 DOI: 10.7554/elife.56026] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
The human fungal pathogen Cryptococcus deuterogattii is RNAi-deficient and lacks active transposons in its genome. C. deuterogattii has regional centromeres that contain only transposon relics. To investigate the impact of centromere loss on the C. deuterogattii genome, either centromere 9 or 10 was deleted. Deletion of either centromere resulted in neocentromere formation and interestingly, the genes covered by these neocentromeres maintained wild-type expression levels. In contrast to cen9∆ mutants, cen10∆ mutant strains exhibited growth defects and were aneuploid for chromosome 10. At an elevated growth temperature (37°C), the cen10∆ chromosome was found to have undergone fusion with another native chromosome in some isolates and this fusion restored wild-type growth. Following chromosomal fusion, the neocentromere was inactivated, and the native centromere of the fused chromosome served as the active centromere. The neocentromere formation and chromosomal fusion events observed in this study in C. deuterogattii may be similar to events that triggered genomic changes within the Cryptococcus/Kwoniella species complex and may contribute to speciation throughout the eukaryotic domain.
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Affiliation(s)
- Klaas Schotanus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
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23
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Partner Choice in Spontaneous Mitotic Recombination in Wild Type and Homologous Recombination Mutants of Candida albicans. G3-GENES GENOMES GENETICS 2019; 9:3631-3644. [PMID: 31690596 PMCID: PMC6829120 DOI: 10.1534/g3.119.400516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Candida albicans, the most common fungal pathogen, is a diploid with a genome that is rich in repeats and has high levels of heterozygosity. To study the role of different recombination pathways on direct-repeat recombination, we replaced either allele of the RAD52 gene (Chr6) with the URA-blaster cassette (hisG-URA3-hisG), measured rates of URA3 loss as resistance to 5-fluoroorotic acid (5FOAR) and used CHEF Southern hybridization and SNP-RFLP analysis to identify recombination mechanisms and their frequency in wildtype and recombination mutants. FOAR rates varied little across different strain backgrounds. In contrast, the type and frequency of mechanisms underlying direct repeat recombination varied greatly. For example, wildtype, rad59 and lig4 strains all displayed a bias for URA3 loss via pop-out/deletion vs. inter-homolog recombination and this bias was reduced in rad51 mutants. In addition, in rad51-derived 5FOAR strains direct repeat recombination was associated with ectopic translocation (5%), chromosome loss/truncation (14%) and inter-homolog recombination (6%). In the absence of RAD52, URA3 loss was mostly due to chromosome loss and truncation (80–90%), and the bias of retained allele frequency points to the presence of a recessive lethal allele on Chr6B. However, a few single-strand annealing (SSA)-like events were identified and these were independent of either Rad59 or Lig4. Finally, the specific sizes of Chr6 truncations suggest that the inserted URA-blaster could represent a fragile site.
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24
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Yamazaki H, Shirakawa K, Matsumoto T, Hirabayashi S, Murakawa Y, Kobayashi M, Sarca AD, Kazuma Y, Matsui H, Maruyama W, Fukuda H, Shirakawa R, Shindo K, Ri M, Iida S, Takaori-Kondo A. Endogenous APOBEC3B Overexpression Constitutively Generates DNA Substitutions and Deletions in Myeloma Cells. Sci Rep 2019; 9:7122. [PMID: 31073151 PMCID: PMC6509214 DOI: 10.1038/s41598-019-43575-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 04/26/2019] [Indexed: 02/07/2023] Open
Abstract
Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC) DNA cytosine deaminases have emerged as potential genomic mutators in various cancers. Multiple myeloma accumulates APOBEC signature mutations as it progresses; however, the mechanisms underlying APOBEC signature acquisition and its consequences remain elusive. In this study, we examined the significance and clinical impact of APOBEC3B (A3B) activity in multiple myeloma. Among APOBECs, only highly expressed A3B was associated with poor prognosis in myeloma patients, independent of other known poor prognostic factors. Quantitative PCR revealed that CD138-positive primary myeloma cells and myeloma cell lines exhibited remarkably high A3B expression levels. Interestingly, lentiviral A3B knockdown prevented the generation of deletion and loss-of-function mutations in exogenous DNA, whereas in control cells, these mutations accumulated with time. A3B knockdown also decreased the basal levels of γ-H2AX foci, suggesting that A3B promotes constitutive DNA double-strand breaks in myeloma cells. Importantly, among control shRNA-transduced cells, we observed the generation of clones that harboured diverse mutations in exogenous genes and several endogenous genes frequently mutated in myeloma, including TP53. Taken together, the results suggest that A3B constitutively mutates the tumour genome beyond the protection of the DNA repair system, which may lead to clonal evolution and genomic instability in myeloma.
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Affiliation(s)
- Hiroyuki Yamazaki
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Kotaro Shirakawa
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Tadahiko Matsumoto
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Shigeki Hirabayashi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.,RIKEN-HMC Clinical Omics Unit, RIKEN Baton Zone Program, Kanagawa, 230-0045, Japan
| | - Yasuhiro Murakawa
- RIKEN-HMC Clinical Omics Unit, RIKEN Baton Zone Program, Kanagawa, 230-0045, Japan.,RIKEN Preventive Medicine and Diagnosis Innovation Program, Kanagawa, 230-0045, Japan
| | - Masayuki Kobayashi
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Anamaria Daniela Sarca
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Yasuhiro Kazuma
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Hiroyuki Matsui
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Wataru Maruyama
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Hirofumi Fukuda
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Ryutaro Shirakawa
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan
| | - Keisuke Shindo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Masaki Ri
- Department of Hematology and Oncology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinsuke Iida
- Department of Hematology and Oncology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.
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25
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Lee K, Ji JH, Yoon K, Che J, Seol JH, Lee SE, Shim EY. Microhomology Selection for Microhomology Mediated End Joining in Saccharomyces cerevisiae. Genes (Basel) 2019; 10:genes10040284. [PMID: 30965655 PMCID: PMC6523938 DOI: 10.3390/genes10040284] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 12/03/2022] Open
Abstract
Microhomology-mediated end joining (MMEJ) anneals short, imperfect microhomologies flanking DNA breaks, producing repair products with deletions in a Ku- and RAD52-independent fashion. Puzzlingly, MMEJ preferentially selects certain microhomologies over others, even when multiple microhomologies are available. To define rules and parameters for microhomology selection, we altered the length, the position, and the level of mismatches to the microhomologies flanking homothallic switching (HO) endonuclease-induced breaks and assessed their effect on MMEJ frequency and the types of repair product formation. We found that microhomology of eight to 20 base pairs carrying no more than 20% mismatches efficiently induced MMEJ. Deletion of MSH6 did not impact MMEJ frequency. MMEJ preferentially chose a microhomology pair that was more proximal from the break. Interestingly, MMEJ events preferentially retained the centromere proximal side of the HO break, while the sequences proximal to the telomere were frequently deleted. The asymmetry in the deletional profile among MMEJ products was reduced when HO was induced on the circular chromosome. The results provide insight into how cells search and select microhomologies for MMEJ in budding yeast.
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Affiliation(s)
- Kihoon Lee
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| | - Jae-Hoon Ji
- Genomic Instability Research Center, Ajou University School of Medicine. 164, World Cup-ro, Yeongtong-gu, Suwon 16499, Korea.
| | - Kihoon Yoon
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| | - Jun Che
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| | - Ja-Hwan Seol
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| | - Sang Eun Lee
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
| | - Eun Yong Shim
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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26
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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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27
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GC content elevates mutation and recombination rates in the yeast Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2018; 115:E7109-E7118. [PMID: 29987035 PMCID: PMC6064992 DOI: 10.1073/pnas.1807334115] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The chromosomes of many eukaryotes have regions of high GC content interspersed with regions of low GC content. In the yeast Saccharomyces cerevisiae, high-GC regions are often associated with high levels of meiotic recombination. In this study, we constructed URA3 genes that differ substantially in their base composition [URA3-AT (31% GC), URA3-WT (43% GC), and URA3-GC (63% GC)] but encode proteins with the same amino acid sequence. The strain with URA3-GC had an approximately sevenfold elevated rate of ura3 mutations compared with the strains with URA3-WT or URA3-AT About half of these mutations were single-base substitutions and were dependent on the error-prone DNA polymerase ζ. About 30% were deletions or duplications between short (5-10 base) direct repeats resulting from DNA polymerase slippage. The URA3-GC gene also had elevated rates of meiotic and mitotic recombination relative to the URA3-AT or URA3-WT genes. Thus, base composition has a substantial effect on the basic parameters of genome stability and evolution.
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28
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Yanik M, Ponnam SPG, Wimmer T, Trimborn L, Müller C, Gambert I, Ginsberg J, Janise A, Domicke J, Wende W, Lorenz B, Stieger K. Development of a Reporter System to Explore MMEJ in the Context of Replacing Large Genomic Fragments. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 11:407-415. [PMID: 29858075 PMCID: PMC5992787 DOI: 10.1016/j.omtn.2018.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/13/2018] [Accepted: 03/20/2018] [Indexed: 01/21/2023]
Abstract
Common genome-editing strategies are either based on non-homologous end joining (NHEJ) or, in the presence of a template DNA, based on homologous recombination with long (homology-directed repair [HDR]) or short (microhomology-mediated end joining [MMEJ]) homologous sequences. In the current study, we aim to develop a model system to test the activity of MMEJ after CRISPR/Cas9-mediated cleavage in cell culture. Following successful proof of concept in an episomally based reporter system, we tested template plasmids containing a promoter-less luciferase gene flanked by microhomologous sequences (mhs) of different length (5, 10, 15, 20, 30, and 50 bp) that are complementary to the mouse retinitis pigmentosa GTPase regulator (RPGR)-ORF15, which is under the control of a CMV promoter stably integrated into a HEK293 cell line. Luciferase signal appearance represented successful recombination events and was highest when the mhs were 5 bp long, while longer mhs revealed lower luciferase signal. In addition, presence of Csy4 RNase was shown to increase luciferase signaling. The luciferase reporter system is a valuable tool to study the input of the different DNA repair mechanisms in the replacement of large DNA sequences by mhs.
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Affiliation(s)
- Mert Yanik
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Surya Prakash Goud Ponnam
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany; Department of Molecular Biology & Biotechnology, Tezpur University, Napaam, Assam 784028, India
| | - Tobias Wimmer
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Lennart Trimborn
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Carina Müller
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Isabel Gambert
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Johanna Ginsberg
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Annabella Janise
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Janina Domicke
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Wolfgang Wende
- Institute for Biochemistry, Justus-Liebig-University, Giessen 35392, Germany
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany
| | - Knut Stieger
- Department of Ophthalmology, Justus-Liebig-University, Giessen 35392, Germany.
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29
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Ku DNA End-Binding Activity Promotes Repair Fidelity and Influences End-Processing During Nonhomologous End-Joining in Saccharomyces cerevisiae. Genetics 2018; 209:115-128. [PMID: 29500182 DOI: 10.1534/genetics.117.300672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 02/25/2018] [Indexed: 12/21/2022] Open
Abstract
The Ku heterodimer acts centrally in nonhomologous end-joining (NHEJ) of DNA double-strand breaks (DSB). Saccharomyces cerevisiae Ku, like mammalian Ku, binds and recruits NHEJ factors to DSB ends. Consequently, NHEJ is virtually absent in yeast Ku null (yku70∆ or yku80∆) strains. Previously, we unexpectedly observed imprecise NHEJ proficiency in a yeast Ku mutant with impaired DNA end-binding (DEB). However, how DEB impairment supported imprecise NHEJ was unknown. Here, we found imprecise NHEJ proficiency to be a feature of a panel of DEB-impaired Ku mutants and that DEB impairment resulted in a deficiency in precise NHEJ. These results suggest that DEB-impaired Ku specifically promotes error-prone NHEJ. Epistasis analysis showed that classical NHEJ factors, as well as novel and previously characterized NHEJ-specific residues of Ku, are required for the distinct error-prone repair in a Ku DEB mutant. However, sequencing of repair junctions revealed that imprecise repair in Ku DEB mutants was almost exclusively characterized by small deletions, in contrast to the majority of insertions that define imprecise repair in wild-type strains. Notably, while sequencing indicated a lack of Pol4-dependent insertions at the site of repair, Pol2 exonuclease activity, which mediates small deletions in NHEJ, contributed to imprecise NHEJ in a Ku DEB mutant. The deletions were smaller than in Ku-independent microhomology-mediated end-joining (MMEJ) and were neither promoted by Mre11 nuclease activity nor Sae2 Thus, the quality of Ku's engagement at the DNA end influences end-processing during NHEJ and DEB impairment unmasks a Ku-dependent error-prone pathway of end-joining distinct from MMEJ.
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30
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Khodaverdian VY, Hanscom T, Yu AM, Yu TL, Mak V, Brown AJ, Roberts SA, McVey M. Secondary structure forming sequences drive SD-MMEJ repair of DNA double-strand breaks. Nucleic Acids Res 2018; 45:12848-12861. [PMID: 29121353 PMCID: PMC5728401 DOI: 10.1093/nar/gkx1056] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 10/18/2017] [Indexed: 12/29/2022] Open
Abstract
Alternative end-joining (alt-EJ) repair of DNA double-strand breaks is associated with deletions, chromosome translocations, and genome instability. Alt-EJ frequently uses annealing of microhomologous sequences to tether broken ends. When accessible pre-existing microhomologies do not exist, we have postulated that new microhomologies can be created via limited DNA synthesis at secondary-structure forming sequences. This model, called synthesis-dependent microhomology-mediated end joining (SD-MMEJ), predicts that differences between DNA sequences near double-strand breaks should alter repair outcomes in predictable ways. To test this hypothesis, we injected plasmids with sequence variations flanking an I-SceI endonuclease recognition site into I-SceI expressing Drosophila embryos and used Illumina amplicon sequencing to compare repair junctions. As predicted by the model, we found that small changes in sequences near the I-SceI site had major impacts on the spectrum of repair junctions. Bioinformatic analyses suggest that these repair differences arise from transiently forming loops and hairpins within 30 nucleotides of the break. We also obtained evidence for ‘trans SD-MMEJ,’ involving at least two consecutive rounds of microhomology annealing and synthesis across the break site. These results highlight the importance of sequence context for alt-EJ repair and have important implications for genome editing and genome evolution.
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Affiliation(s)
- Varandt Y Khodaverdian
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Terrence Hanscom
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Amy Marie Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Taylor L Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Victoria Mak
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Alexander J Brown
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Mitch McVey
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
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31
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Processing-Challenges Generated by Clusters of DNA Double-Strand Breaks Underpin Increased Effectiveness of High-LET Radiation and Chromothripsis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:149-168. [DOI: 10.1007/978-981-13-0593-1_10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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32
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Carbonell-Bejerano P, Royo C, Torres-Pérez R, Grimplet J, Fernandez L, Franco-Zorrilla JM, Lijavetzky D, Baroja E, Martínez J, García-Escudero E, Ibáñez J, Martínez-Zapater JM. Catastrophic Unbalanced Genome Rearrangements Cause Somatic Loss of Berry Color in Grapevine. PLANT PHYSIOLOGY 2017; 175:786-801. [PMID: 28811336 PMCID: PMC5619900 DOI: 10.1104/pp.17.00715] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/13/2017] [Indexed: 05/21/2023]
Abstract
Grape (Vitis vinifera) color somatic variants that can be used to develop new grapevine cultivars occasionally appear associated with deletion events of uncertain origin. To understand the mutational mechanisms generating somatic structural variation in grapevine, we compared the Tempranillo Blanco (TB) white berry somatic variant with its black berry ancestor, Tempranillo Tinto. Whole-genome sequencing uncovered a catastrophic genome rearrangement in TB that caused the hemizygous deletion of 313 genes, including the loss of the functional copy for the MYB transcription factors required for anthocyanin pigmentation in the berry skin. Loss of heterozygosity and decreased copy number delimited interspersed monosomic and disomic regions in the right arm of linkage groups 2 and 5. At least 11 validated clustered breakpoints involving intrachromosomal and interchromosomal translocations between three linkage groups flanked the deleted fragments, which, according to segregation analyses, are phased in a single copy of each of the affected chromosomes. These hallmarks, along with the lack of homology between breakpoint joins and the randomness of the order and orientation of the rearranged fragments, are all consistent with a chromothripsis-like pattern generated after chromosome breakage and illegitimate rejoining. This unbalanced genome reshuffling has additional consequences in reproductive development. In TB, lack of sexual transmission of rearranged chromosomes associates with low gamete viability, which compromises fruit set and decreases fruit production. Our findings show that catastrophic genome rearrangements arise spontaneously and stabilize during plant somatic growth. These dramatic rearrangements generate new interesting phenotypes that can be selected for the improvement of vegetatively propagated plant species.
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Affiliation(s)
- Pablo Carbonell-Bejerano
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Carolina Royo
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Rafael Torres-Pérez
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Jérôme Grimplet
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Lucie Fernandez
- Unité Mixte de Recherche Biologie du Fruit et Pathologie, Institut National de la Recherche Agronomique, F-33140 Villenave d'Ornon, France
| | | | - Diego Lijavetzky
- Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas-UNCuyo-FCA, M5528AHB Chacras de Coria, Argentina
| | - Elisa Baroja
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Juana Martínez
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Enrique García-Escudero
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - Javier Ibáñez
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
| | - José Miguel Martínez-Zapater
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja, 26007 Logroño, Spain
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Seol JH, Shim EY, Lee SE. Microhomology-mediated end joining: Good, bad and ugly. Mutat Res 2017; 809:81-87. [PMID: 28754468 DOI: 10.1016/j.mrfmmm.2017.07.002] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/21/2017] [Accepted: 07/03/2017] [Indexed: 01/06/2023]
Abstract
DNA double-strand breaks (DSBs) are induced by a variety of genotoxic agents, including ionizing radiation and chemotherapy drugs for treating cancers. The elimination of DSBs proceeds via distinctive error-free and error-prone pathways. Repair by homologous recombination (HR) is largely error-free and mediated by RAD51/BRCA2 gene products. Classical non-homologous end joining (C-NHEJ) requires the Ku heterodimer and can efficiently rejoin breaks, with occasional loss or gain of DNA information. Recently, evidence has unveiled another DNA end-joining mechanism that is independent of recombination factors and Ku proteins, termed alternative non-homologous end joining (A-NHEJ). While A-NHEJ-mediated repair does not require homology, in a subtype of A-NHEJ, DSB breaks are sealed by microhomology (MH)-mediated base-pairing of DNA single strands, followed by nucleolytic trimming of DNA flaps, DNA gap filling, and DNA ligation, yielding products that are always associated with DNA deletion. This highly error-prone DSB repair pathway is termed microhomology-mediated end joining (MMEJ). Dissecting the mechanisms of MMEJ is of great interest because of its potential to destabilize the genome through gene deletions and chromosomal rearrangements in cells deficient in canonical repair pathways, including HR and C-NHEJ. In addition, evidence now suggests that MMEJ plays a physiological role in normal cells.
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Affiliation(s)
- Ja-Hwan Seol
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States
| | - Eun Yong Shim
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States
| | - Sang Eun Lee
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States.
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Nilles N, Fahrenkrog B. Taking a Bad Turn: Compromised DNA Damage Response in Leukemia. Cells 2017; 6:cells6020011. [PMID: 28471392 PMCID: PMC5492015 DOI: 10.3390/cells6020011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/07/2017] [Accepted: 04/25/2017] [Indexed: 02/01/2023] Open
Abstract
Genomic integrity is of outmost importance for the survival at the cellular and the organismal level and key to human health. To ensure the integrity of their DNA, cells have evolved maintenance programs collectively known as the DNA damage response. Particularly challenging for genome integrity are DNA double-strand breaks (DSB) and defects in their repair are often associated with human disease, including leukemia. Defective DSB repair may not only be disease-causing, but further contribute to poor treatment outcome and poor prognosis in leukemia. Here, we review current insight into altered DSB repair mechanisms identified in leukemia. While DSB repair is somewhat compromised in all leukemic subtypes, certain key players of DSB repair are particularly targeted: DNA-dependent protein kinase (DNA-PK) and Ku70/80 in the non-homologous end-joining pathway, as well as Rad51 and breast cancer 1/2 (BRCA1/2), key players in homologous recombination. Defects in leukemia-related DSB repair may not only arise from dysfunctional repair components, but also indirectly from mutations in key regulators of gene expression and/or chromatin structure, such as p53, the Kirsten ras oncogene (K-RAS), and isocitrate dehydrogenase 1 and 2 (IDH1/2). A detailed understanding of the basis for defective DNA damage response (DDR) mechanisms for each leukemia subtype may allow to further develop new treatment methods to improve treatment outcome and prognosis for patients.
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Affiliation(s)
- Nadine Nilles
- Institute for Molecular Biology and Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium.
| | - Birthe Fahrenkrog
- Institute for Molecular Biology and Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium.
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Sinha S, Li F, Villarreal D, Shim JH, Yoon S, Myung K, Shim EY, Lee SE. Microhomology-mediated end joining induces hypermutagenesis at breakpoint junctions. PLoS Genet 2017; 13:e1006714. [PMID: 28419093 PMCID: PMC5413072 DOI: 10.1371/journal.pgen.1006714] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 05/02/2017] [Accepted: 03/24/2017] [Indexed: 01/12/2023] Open
Abstract
Microhomology (MH) flanking a DNA double-strand break (DSB) drives chromosomal rearrangements but its role in mutagenesis has not yet been analyzed. Here we determined the mutation frequency of a URA3 reporter gene placed at multiple locations distal to a DSB, which is flanked by different sizes (15-, 18-, or 203-bp) of direct repeat sequences for efficient repair in budding yeast. Induction of a DSB accumulates mutations in the reporter gene situated up to 14-kb distal to the 15-bp MH, but more modestly to those carrying 18- and 203-bp or no homology. Increased mutagenesis in MH-mediated end joining (MMEJ) appears coupled to its slower repair kinetics and the extensive resection occurring at flanking DNA. Chromosomal translocations via MMEJ also elevate mutagenesis of the flanking DNA sequences 7.1 kb distal to the breakpoint junction as compared to those without MH. The results suggest that MMEJ could destabilize genomes by triggering structural alterations and increasing mutation burden. Recurrent chromosome translocations juxtapose chromosomal fragments and alter expression of tumor suppressors or oncogenes at or near breakpoint junctions to develop distinct types of leukemias and childhood sarcomas. The prevalence of 2–20 bp of imperfect overlapping sequences (a.k.a. microhomology [MH]) at the breakpoint junctions suggests the type of repair events joining two chromosomal fragments and the formation of oncogenic chromosomal translocations. In this study, we discovered that MH-mediated end joining (MMEJ) operates with kinetics markedly slower than other repair options. The slower kinetics leads to extensive resection and drives hypermutagenesis at sequences flanking the break site. We also found that MH-mediated chromosomal translocations accumulate mutations at sequences up to several kilobases distal to the breakpoint junction as compared to those without MH. Our results revealed that MH contributes to genetic instability by facilitating chromosomal translocations and increasing mutational load at the sequences flanking the breakpoints.
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Affiliation(s)
- Supriya Sinha
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Fuyang Li
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Diana Villarreal
- Children's Hospital of San Antonio, Baylor College of Medicine, San Antonio, TX, United States of America
| | - Jae Hoon Shim
- Korea Institute of Radiological & Medical Sciences (KIRAMS), 75 Nowon-ro, Nowon-gu, Seoul, Republic of Korea
| | - Suhyeon Yoon
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44818, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44818, Republic of Korea
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44818, Republic of Korea
| | - Eun Yong Shim
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Sang Eun Lee
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
- * E-mail:
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Tu T, Budzinska MA, Shackel NA, Urban S. HBV DNA Integration: Molecular Mechanisms and Clinical Implications. Viruses 2017; 9:v9040075. [PMID: 28394272 PMCID: PMC5408681 DOI: 10.3390/v9040075] [Citation(s) in RCA: 231] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
Chronic infection with the Hepatitis B Virus (HBV) is a major cause of liver-related morbidity and mortality. One peculiar observation in cells infected with HBV (or with closely‑related animal hepadnaviruses) is the presence of viral DNA integration in the host cell genome, despite this form being a replicative dead-end for the virus. The frequent finding of somatic integration of viral DNA suggests an evolutionary benefit for the virus; however, the mechanism of integration, its functions, and the clinical implications remain unknown. Here we review the current body of knowledge of HBV DNA integration, with particular focus on the molecular mechanisms and its clinical implications (including the possible consequences of replication-independent antigen expression and its possible role in hepatocellular carcinoma). HBV DNA integration is likely to influence HBV replication, persistence, and pathogenesis, and so deserves greater attention in future studies.
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Affiliation(s)
- Thomas Tu
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany.
| | - Magdalena A Budzinska
- Centenary Institute, The University of Sydney, Sydney, NSW 2050, Australia.
- Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Nicholas A Shackel
- Centenary Institute, The University of Sydney, Sydney, NSW 2050, Australia.
- Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.
- Liverpool Hospital, Gastroenterology, Sydney, NSW 2170, Australia.
| | - Stephan Urban
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany.
- German Center for Infection Research (DZIF), Heidelberg Partner Site, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany.
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Wright DG, Castore R, Shi R, Mallick A, Ennis DG, Harrison L. Mycobacterium tuberculosis and Mycobacterium marinum non-homologous end-joining proteins can function together to join DNA ends in Escherichia coli. Mutagenesis 2017; 32:245-256. [PMID: 27613236 PMCID: PMC5989629 DOI: 10.1093/mutage/gew042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 08/03/2016] [Indexed: 12/26/2022] Open
Abstract
Mycobacterium tuberculosis and Mycobacterium smegmatis express a Ku protein and a DNA ligase D and are able to repair DNA double strand breaks (DSBs) by non-homologous end-joining (NHEJ). This pathway protects against DNA damage when bacteria are in stationary phase. Mycobacterium marinum is a member of this mycobacterium family and like M. tuberculosis is pathogenic. M. marinum lives in water, forms biofilms and infects fish and frogs. M. marinum is a biosafety level 2 (BSL2) organism as it can infect humans, although infections are limited to the skin. M. marinum is accepted as a model to study mycobacterial pathogenesis, as M. marinum and M. tuberculosis are genetically closely related and have similar mechanisms of survival and persistence inside macrophage. The aim of this study was to determine whether M. marinum could be used as a model to understand M. tuberculosis NHEJ repair. We identified and cloned the M. marinum genes encoding NHEJ proteins and generated E. coli strains that express the M. marinum Ku (Mm-Ku) and ligase D (Mm-Lig) individually or together (LHmKumLig strain) from expression vectors integrated at phage attachment sites in the genome. We demonstrated that Mm-Ku and Mm-Lig are both required to re-circularize Cla I-linearized plasmid DNA in E. coli. We compared repair of strain LHmKumLig with that of an E. coli strain (BWKuLig#2) expressing the M. tuberculosis Ku (Mt-Ku) and ligase D (Mt-Lig), and found that LHmKumLig performed 3.5 times more repair and repair was more accurate than BWKuLig#2. By expressing the Mm-Ku with the Mt-Lig, or the Mt-Ku with the Mm-Lig in E. coli, we have shown that the NHEJ proteins from M. marinum and M. tuberculosis can function together to join DNA DSBs. NHEJ repair is therefore conserved between the two species. Consequently, M. marinum is a good model to study NHEJ repair during mycobacterial pathogenesis.
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Affiliation(s)
- Douglas G Wright
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Reneau Castore
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Runhua Shi
- Department of Medicine and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Amrita Mallick
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, USA
| | - Don G Ennis
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, USA
| | - Lynn Harrison
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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Lieberman HB, Panigrahi SK, Hopkins KM, Wang L, Broustas CG. p53 and RAD9, the DNA Damage Response, and Regulation of Transcription Networks. Radiat Res 2017; 187:424-432. [PMID: 28140789 DOI: 10.1667/rr003cc.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The way cells respond to DNA damage is important since inefficient repair or misrepair of lesions can have deleterious consequences, including mutation, genomic instability, neurodegenerative disorders, premature aging, cancer or death. Whether damage occurs spontaneously as a byproduct of normal metabolic processes, or after exposure to exogenous agents, cells muster a coordinated, complex DNA damage response (DDR) to mitigate potential harmful effects. A variety of activities are involved to promote cell survival, and include DNA repair, DNA damage tolerance, as well as transient cell cycle arrest to provide time for repair before entry into critical cell cycle phases, an event that could be lethal if traversal occurs while damage is present. When such damage is prolonged or not repairable, senescence, apoptosis or autophagy is induced. One major level of DDR regulation occurs via the orchestrated transcriptional control of select sets of genes encoding proteins that mediate the response. p53 is a transcription factor that transactivates specific DDR downstream genes through binding DNA consensus sequences usually in or near target gene promoter regions. The profile of p53-regulated genes activated at any given time varies, and is dependent upon type of DNA damage or stress experienced, exact composition of the consensus DNA binding sequence, presence of other DNA binding proteins, as well as cell context. RAD9 is another protein critical for the response of cells to DNA damage, and can also selectively regulate gene transcription. The limited studies addressing the role of RAD9 in transcription regulation indicate that the protein transactivates at least one of its target genes, p21/waf1/cip1, by binding to DNA sequences demonstrated to be a p53 response element. NEIL1 is also regulated by RAD9 through a similar DNA sequence, though not yet directly verified as a bonafide p53 response element. These findings suggest a novel pathway whereby p53 and RAD9 control the DDR through a shared mechanism involving an overlapping network of downstream target genes. Details and unresolved questions about how these proteins coordinate or compete to execute the DDR through transcriptional reprogramming, as well as biological implications, are discussed.
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Affiliation(s)
- Howard B Lieberman
- a Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032; and.,b Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032
| | - Sunil K Panigrahi
- a Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032; and
| | - Kevin M Hopkins
- a Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032; and
| | - Li Wang
- a Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032; and
| | - Constantinos G Broustas
- a Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032; and
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Wang H, Xu X. Microhomology-mediated end joining: new players join the team. Cell Biosci 2017; 7:6. [PMID: 28101326 PMCID: PMC5237343 DOI: 10.1186/s13578-017-0136-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 01/06/2017] [Indexed: 01/29/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most deleterious type of DNA damage in cells arising from endogenous and exogenous attacks on the genomic DNA. Timely and properly repair of DSBs is important for genomic integrity and survival. MMEJ is an error-prone repair mechanism for DSBs, which relies on exposed microhomologous sequence flanking broken junction to fix DSBs in a Ku- and ligase IV-independent manner. Recently, significant progress has been made in MMEJ mechanism study. In this review, we will summarize its biochemical activities of several newly identified MMEJ factors and their biological significance.
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Affiliation(s)
- Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, 100048 China
| | - Xingzhi Xu
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing, 100048 China ; Shenzhen University School of Medicine, Shenzhen, 518060 Guangdong China
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40
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Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome. Proc Natl Acad Sci U S A 2016; 113:15036-15041. [PMID: 27930295 DOI: 10.1073/pnas.1608979113] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sex determination is a fundamental developmental pathway governing male and female differentiation, with profound implications for morphology, reproductive strategies, and behavior. In animals, sex differences between males and females are generally determined by genetic factors carried by sex chromosomes. Sex chromosomes are remarkably variable in origin and can differ even between closely related species, indicating that transitions occur frequently and independently in different groups of organisms. The evolutionary causes underlying sex chromosome turnover are poorly understood, however. Here we provide evidence indicating that Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. The Wolbachia insert shows perfect linkage to the female sex, occurs in a male genetic background (i.e., lacking the ancestral W female sex chromosome), and is hemizygous. Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs, and that the chromosome carrying the insert is a new W sex chromosome. Thus, bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes. We conclude that sex ratio distorters, such as Wolbachia endosymbionts, can be powerful agents of evolutionary transitions in sex determination systems in animals.
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41
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Regulation of non-homologous end joining via post-translational modifications of components of the ligation step. Curr Genet 2016; 63:591-605. [PMID: 27915381 DOI: 10.1007/s00294-016-0670-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/25/2016] [Accepted: 11/26/2016] [Indexed: 12/29/2022]
Abstract
DNA double-strand breaks are the most serious type of DNA damage and non-homologous end joining (NHEJ) is an important pathway for their repair. In Saccharomyces cerevisiae, three complexes mediate the canonical NHEJ pathway, Ku (Ku70/Ku80), MRX (Mre11/Rad50/Xrs2) and DNA ligase IV (Dnl4/Lif1). Mammalian NHEJ is more complex, primarily as a consequence of the fact that more factors are involved in the process, and also because higher chromatin organization and more complex regulatory networks exist in mammals. In addition, a stronger interconnection between the NHEJ and DNA damage response (DDR) pathways seems to occur in mammals compared to yeast. DDR employs multiple post-translational modifications (PTMs) of the target proteins and mutual crosstalk among them to ensure highly efficient down-stream effects. Checkpoint-mediated phosphorylation is the best understood PTM that regulates DDR, although recently SUMOylation has also been shown to be involved. Both phosphorylation and SUMOylation affect components of NHEJ. In this review, we discuss a role of these two PTMs in regulation of NHEJ via targeting the components of the ligation step.
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42
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Abstract
Double-strand breaks (DSBs) pose a severe challenge to genome integrity; consequently, cells have developed efficient mechanisms to repair DSBs through several pathways of homologous recombination and other nonhomologous end-joining processes. Much of our understanding of these pathways has come from the analysis of site-specific DSBs created by the HO endonuclease in the budding yeast Saccharomyces cerevisiae. I was fortunate to get in on the ground floor of analyzing the fate of synchronously induced DSBs through the study of what I coined "in vivo biochemistry." I have had the remarkable good fortune to profit from the development of new techniques that have permitted an ever more detailed dissection of these repair mechanisms, which are described here.
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Affiliation(s)
- James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02453;
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43
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In vivo genome editing as a potential treatment strategy for inherited retinal dystrophies. Prog Retin Eye Res 2016; 56:1-18. [PMID: 27623223 DOI: 10.1016/j.preteyeres.2016.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/06/2016] [Accepted: 09/08/2016] [Indexed: 12/20/2022]
Abstract
In vivo genome editing represents an emerging field in the treatment of monogenic disorders, as it may constitute a solution to the current hurdles in classic gene addition therapy, which are the low levels and limited duration of transgene expression. Following the introduction of a double strand break (DSB) at the mutational site by highly specific endonucleases, such as TALENs (transcription activator like effector nucleases) or RNA based nucleases (clustered regulatory interspaced short palindromic repeats - CRISPR-Cas), the cell's own DNA repair machinery restores integrity to the DNA strand and corrects the mutant sequence, thus allowing the cell to produce protein levels as needed. The DNA repair happens either through the error prone non-homologous end-joining (NHEJ) pathway or with high fidelity through homology directed repair (HDR) in the presence of a DNA donor template. A third pathway called microhomology mediated endjoining (MMEJ) has been recently discovered. In this review, the authors focus on the different DNA repair mechanisms, the current state of the art tools for genome editing and the particularities of the retina and photoreceptors with regard to in vivo therapeutic approaches. Finally, current attempts in the field of retinal in vivo genome editing are discussed and future directions of research identified.
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44
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DNA Damage and Pulmonary Hypertension. Int J Mol Sci 2016; 17:ijms17060990. [PMID: 27338373 PMCID: PMC4926518 DOI: 10.3390/ijms17060990] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/01/2016] [Accepted: 06/16/2016] [Indexed: 01/21/2023] Open
Abstract
Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.
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