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Liljegren MM, Gama JA, Johnsen PJ, Harms K. The recombination initiation functions DprA and RecFOR suppress microindel mutations in Acinetobacter baylyi ADP1. Mol Microbiol 2024. [PMID: 38760330 DOI: 10.1111/mmi.15277] [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: 11/22/2023] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/19/2024]
Abstract
Short-Patch Double Illegitimate Recombination (SPDIR) has been recently identified as a rare mutation mechanism. During SPDIR, ectopic DNA single-strands anneal with genomic DNA at microhomologies and get integrated during DNA replication, presumably acting as primers for Okazaki fragments. The resulting microindel mutations are highly variable in size and sequence. In the soil bacterium Acinetobacter baylyi, SPDIR is tightly controlled by genome maintenance functions including RecA. It is thought that RecA scavenges DNA single-strands and renders them unable to anneal. To further elucidate the role of RecA in this process, we investigate the roles of the upstream functions DprA, RecFOR, and RecBCD, all of which load DNA single-strands with RecA. Here we show that all three functions suppress SPDIR mutations in the wildtype to levels below the detection limit. While SPDIR mutations are slightly elevated in the absence of DprA, they are strongly increased in the absence of both DprA and RecA. This SPDIR-avoiding function of DprA is not related to its role in natural transformation. These results suggest a function for DprA in combination with RecA to avoid potentially harmful microindel mutations, and offer an explanation for the ubiquity of dprA in the genomes of naturally non-transformable bacteria.
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Affiliation(s)
- Mikkel M Liljegren
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - João A Gama
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - Pål J Johnsen
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - Klaus Harms
- Microbial Pharmacology and Population Biology Research Group, Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
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2
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Shitrit A, Nisnevich V, Rozenshtein N, Kobo H, Phan HV, Tay S, Szpara M, Weitzman MD, Drayman N, Kobiler O. Shared sequence characteristics identified in non-canonical rearrangements of HSV-1 genomes. J Virol 2023; 97:e0095523. [PMID: 37991369 PMCID: PMC10734421 DOI: 10.1128/jvi.00955-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/26/2023] [Indexed: 11/23/2023] Open
Abstract
IMPORTANCE Mutations and genetic rearrangements are the primary driving forces of evolution. Viruses provide valuable model systems for investigating these mechanisms due to their rapid evolutionary rates and vast genetic variability. To investigate genetic rearrangements in the double-stranded DNA genome of herpes simplex virus type 1, the viral population was serially passaged in various cell types. The serial passaging led to formation of defective genomes, resulted from cell-specific non-canonical rearrangements (NCRs). Interestingly, we discovered shared sequence characteristics underlying the formation of these NCRs across all cell types. Moreover, most NCRs identified in clinical samples shared these characteristics. Based on our findings, we propose a model elucidating the formation of NCRs during viral replication within the nucleus of eukaryotic cells.
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Affiliation(s)
- Alina Shitrit
- Department of Clinical Microbiology and Immunology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Valerya Nisnevich
- Department of Clinical Microbiology and Immunology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nofar Rozenshtein
- Department of Clinical Microbiology and Immunology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hila Kobo
- Genomic Research Unit, Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | - Hoang Van Phan
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, Illinois, USA
| | - Savaş Tay
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, Illinois, USA
| | - Moriah Szpara
- Department of Biochemistry and Molecular Biology, Department of Biology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Matthew D. Weitzman
- Division of Protective Immunity, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nir Drayman
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California, Irvine, California, USA
- Center for Virus Research, University of California, Irvine, California, USA
| | - Oren Kobiler
- Department of Clinical Microbiology and Immunology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
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3
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Al-Zain AM, Nester MR, Ahmed I, Symington LS. Double-strand breaks induce inverted duplication chromosome rearrangements by a DNA polymerase δ-dependent mechanism. Nat Commun 2023; 14:7020. [PMID: 37919272 PMCID: PMC10622511 DOI: 10.1038/s41467-023-42640-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023] Open
Abstract
Inverted duplications, also known as foldback inversions, are commonly observed in cancers and are the major class of chromosome rearrangement recovered from yeast cells lacking Mre11 nuclease activity. Foldback priming at DNA double-strand breaks (DSBs) is one mechanism proposed for the generation of inverted duplications. However, the other pathway steps have not been fully elucidated. Here, we show that a DSB induced near natural inverted repeats drives high frequency inverted duplication in Sae2 and Mre11-deficient cells. We find that DNA polymerase δ proof-reading activity, but not Rad1 nuclease, trims the heterologous flaps formed after foldback annealing. Additionally, Pol32 is required for the generation of inverted duplications, suggesting that Pol δ catalyzes fill-in synthesis primed from the foldback to create a hairpin-capped chromosome that is subsequently replicated to form a dicentric inversion chromosome. Finally, we show that stabilization of the dicentric chromosome after breakage involves telomere capture by non-reciprocal translocation mediated by repeat sequences or by deletion of one centromere.
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Affiliation(s)
- Amr M Al-Zain
- Program in Biological Sciences, Columbia University, New York, NY, 10027, USA
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Mattie R Nester
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Iffat Ahmed
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, 10032, USA.
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4
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Stroik S, Carvajal-Garcia J, Gupta D, Edwards A, Luthman A, Wyatt DW, Dannenberg RL, Feng W, Kunkel TA, Gupta GP, Hedglin M, Wood R, Doublié S, Rothenberg E, Ramsden DA. Stepwise requirements for polymerases δ and θ in theta-mediated end joining. Nature 2023; 623:836-841. [PMID: 37968395 PMCID: PMC10959172 DOI: 10.1038/s41586-023-06729-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/06/2023] [Indexed: 11/17/2023]
Abstract
Timely repair of chromosomal double-strand breaks is required for genome integrity and cellular viability. The polymerase theta-mediated end joining pathway has an important role in resolving these breaks and is essential in cancers defective in other DNA repair pathways, thus making it an emerging therapeutic target1. It requires annealing of 2-6 nucleotides of complementary sequence, microhomologies, that are adjacent to the broken ends, followed by initiation of end-bridging DNA synthesis by polymerase θ. However, the other pathway steps remain inadequately defined, and the enzymes required for them are unknown. Here we demonstrate requirements for exonucleolytic digestion of unpaired 3' tails before polymerase θ can initiate synthesis, then a switch to a more accurate, processive and strand-displacing polymerase to complete repair. We show the replicative polymerase, polymerase δ, is required for both steps; its 3' to 5' exonuclease activity for flap trimming, then its polymerase activity for extension and completion of repair. The enzymatic steps that are essential and specific to this pathway are mediated by two separate, sequential engagements of the two polymerases. The requisite coupling of these steps together is likely to be facilitated by physical association of the two polymerases. This pairing of polymerase δ with a polymerase capable of end-bridging synthesis, polymerase θ, may help to explain why the normally high-fidelity polymerase δ participates in genome destabilizing processes such as mitotic DNA synthesis2 and microhomology-mediated break-induced replication3.
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Affiliation(s)
- Susanna Stroik
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Dipika Gupta
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Alyssa Edwards
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Adam Luthman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David W Wyatt
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rachel L Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Wanjuan Feng
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Richard Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Dale A Ramsden
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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5
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Shaltz S, Jinks-Robertson S. Genetic control of the error-prone repair of a chromosomal double-strand break with 5' overhangs in yeast. Genetics 2023; 225:iyad122. [PMID: 37418686 PMCID: PMC10471200 DOI: 10.1093/genetics/iyad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/09/2023] Open
Abstract
A targeted double-strand break introduced into the genome of Saccharomyces cerevisiae is repaired by the relatively error-prone nonhomologous end joining (NHEJ) pathway when homologous recombination is not an option. A zinc finger nuclease cleavage site was inserted out-of-frame into the LYS2 locus of a haploid yeast strain to study the genetic control of NHEJ when the ends contain 5' overhangs. Repair events that destroyed the cleavage site were identified either as Lys+ colonies on selective medium or as surviving colonies on rich medium. Junction sequences in Lys+ events solely reflected NHEJ and were influenced by the nuclease activity of Mre11 as well as by the presence/absence of the NHEJ-specific polymerase Pol4 and the translesion-synthesis DNA polymerases Pol ζ and Pol η. Although most NHEJ events were dependent on Pol4, a 29-bp deletion with endpoints in 3-bp repeats was an exception. The Pol4-independent deletion required translesion synthesis polymerases as well as the exonuclease activity of the replicative Pol δ DNA polymerase. Survivors were equally split between NHEJ events and 1.2 or 11.7 kb deletions that reflected microhomology-mediated end joining (MMEJ). MMEJ events required the processive resection activity of Exo1/Sgs1, but there unexpectedly was no dependence on the Rad1-Rad10 endonuclease for the removal of presumptive 3' tails. Finally, NHEJ was more efficient in nongrowing than in growing cells and was most efficient in G0 cells. These studies provide novel insights into the flexibility and complexity of error-prone DSB repair in yeast.
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Affiliation(s)
- Samantha Shaltz
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
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6
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Basalova N, Illarionova M, Skryabina M, Vigovskiy M, Tolstoluzhinskaya A, Primak A, Chechekhina E, Chechekhin V, Karagyaur M, Efimenko A. Advances and Obstacles in Using CRISPR/Cas9 Technology for Non-Coding RNA Gene Knockout in Human Mesenchymal Stromal Cells. Noncoding RNA 2023; 9:49. [PMID: 37736895 PMCID: PMC10514828 DOI: 10.3390/ncrna9050049] [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: 07/03/2023] [Revised: 08/17/2023] [Accepted: 08/22/2023] [Indexed: 09/23/2023] Open
Abstract
Non-coding RNA (ncRNAs) genes have attracted increasing attention in recent years due to their widespread involvement in physiological and pathological processes and regulatory networks. The study of the function and molecular partners of ncRNAs opens up opportunities for the early diagnosis and treatment of previously incurable diseases. However, the classical "loss-of-function" approach in ncRNA function analysis is challenged due to some specific issues. Here, we have studied the potency of two CRISPR/Cas9 variants, wild-type (SpCas9wt) and nickase (SpCas9D10A) programmable nucleases, for the editing of extended DNA sequences in human mesenchymal stromal cells (MSCs). Editing the genes of fibrosis-related hsa-miR-21-5p and hsa-miR-29c-3p, we have shown that a pair of SpCas9D10A molecules can effectively disrupt miRNA genes within the genomes of MSCs. This leads not only to a decrease in the level of knockout miRNA in MSCs and MSC-produced extracellular vesicles, but also to a change in cell physiology and the antifibrotic properties of the cell secretome. These changes correlate well with previously published data for the knockdown of certain miRNAs. The proposed approach can be used to knock out ncRNA genes within the genomes of MSCs or similar cell types in order to study their function in biological processes.
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Affiliation(s)
- Nataliya Basalova
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia; (N.B.); (M.V.); (A.T.)
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Maria Illarionova
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Mariya Skryabina
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Maksim Vigovskiy
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia; (N.B.); (M.V.); (A.T.)
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Anastasia Tolstoluzhinskaya
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia; (N.B.); (M.V.); (A.T.)
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Alexandra Primak
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Elizaveta Chechekhina
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Vadim Chechekhin
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Maxim Karagyaur
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia; (N.B.); (M.V.); (A.T.)
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
| | - Anastasia Efimenko
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia; (N.B.); (M.V.); (A.T.)
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia; (M.I.); (M.S.); (A.P.); (E.C.); (V.C.)
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Laufer VA, Glover TW, Wilson TE. Applications of advanced technologies for detecting genomic structural variation. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108475. [PMID: 37931775 PMCID: PMC10792551 DOI: 10.1016/j.mrrev.2023.108475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/07/2023] [Accepted: 11/02/2023] [Indexed: 11/08/2023]
Abstract
Chromosomal structural variation (SV) encompasses a heterogenous class of genetic variants that exerts strong influences on human health and disease. Despite their importance, many structural variants (SVs) have remained poorly characterized at even a basic level, a discrepancy predicated upon the technical limitations of prior genomic assays. However, recent advances in genomic technology can identify and localize SVs accurately, opening new questions regarding SV risk factors and their impacts in humans. Here, we first define and classify human SVs and their generative mechanisms, highlighting characteristics leveraged by various SV assays. We next examine the first-ever gapless assembly of the human genome and the technical process of assembling it, which required third-generation sequencing technologies to resolve structurally complex loci. The new portions of that "telomere-to-telomere" and subsequent pangenome assemblies highlight aspects of SV biology likely to develop in the near-term. We consider the strengths and limitations of the most promising new SV technologies and when they or longstanding approaches are best suited to meeting salient goals in the study of human SV in population-scale genomics research, clinical, and public health contexts. It is a watershed time in our understanding of human SV when new approaches are expected to fundamentally change genomic applications.
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Affiliation(s)
- Vincent A Laufer
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas W Glover
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas E Wilson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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8
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Wright GM, Menzel J, Tatman PD, Black JC. Transition from Transient DNA Rereplication to Inherited Gene Amplification Following Prolonged Environmental Stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539886. [PMID: 37214911 PMCID: PMC10197558 DOI: 10.1101/2023.05.08.539886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cells require the ability to adapt to changing environmental conditions, however, it is unclear how these changes elicit stable permanent changes in genomes. We demonstrate that, in response to environmental metal exposure, the metallothionein (MT) locus undergoes DNA rereplication generating transient site-specific gene amplifications (TSSGs). Chronic metal exposure allows transition from MT TSSG to inherited MT gene amplification through homologous recombination within and outside of the MT locus. DNA rereplication of the MT locus is suppressed by H3K27me3 and EZH2. Long-term ablation of EZH2 activity eventually leads to integration and inheritance of MT gene amplifications without the selective pressure of metal exposure. The rereplication and inheritance of MT gene amplification is an evolutionarily conserved response to environmental metal from yeast to human. Our results describe a new paradigm for adaptation to environmental stress where targeted, transient DNA rereplication precedes stable inherited gene amplification.
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9
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Shaltz S, Jinks-Robertson S. Genetic control of the error-prone repair of a chromosomal double-strand break with 5' overhangs in yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.04.539391. [PMID: 37205473 PMCID: PMC10187297 DOI: 10.1101/2023.05.04.539391] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A targeted double-strand break introduced into the genome of Saccharomyces cerevisiae is repaired by the relatively error-prone nonhomologous-end joining (NHEJ) pathway when homologous recombination is not an option. A ZFN cleavage site was inserted out-of-frame into the LYS2 locus of a haploid yeast strain to study the genetic control of NHEJ when the ends contain 5' overhangs. Repair events that destroyed the cleavage site were identified either as Lys + colonies on selective medium or as surviving colonies on rich medium. Junction sequences in Lys + events solely reflected NHEJ and were influenced by the nuclease activity of Mre11 as well as by the presence/absence of the NHEJ-specific polymerase Pol4 and the translesion-synthesis DNA polymerases Pol σ and Pol 11. Although most NHEJ events were dependent on Pol4, a 29-bp deletion with endpoints in 3-bp repeats was an exception. The Pol4-independent deletion required TLS polymerases as well as the exonuclease activity of the replicative Pol DNA polymerase. Survivors were equally split between NHEJ events and 1 kb or 11 kb deletions that reflected microhomology-mediated end joining (MMEJ). MMEJ events required the processive resection activity of Exo1/Sgs1, but there unexpectedly was no dependence on the Rad1-Rad10 endonuclease for the removal of presumptive 3' tails. Finally, NHEJ was more efficient in non-growing than in growing cells and was most efficient in G0 cells. These studies provide novel insight into the flexibility and complexity of error-prone DSB repair in yeast.
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Affiliation(s)
- Samantha Shaltz
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
| | - Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
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10
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Shmakova A, Vassetzky Y. lncRNA: A new danger for genome integrity. Int J Cancer 2023; 152:1288-1289. [PMID: 36510743 DOI: 10.1002/ijc.34397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Shmakova
- CNRS, UMR 9018, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France.,Koltzov Institute of Developmental Biology, Moscow, Russia
| | - Yegor Vassetzky
- CNRS, UMR 9018, Université Paris-Saclay, Institut Gustave Roussy, Villejuif, France.,Koltzov Institute of Developmental Biology, Moscow, Russia
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11
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Schusterbauer V, Fischer JE, Gangl S, Schenzle L, Rinnofner C, Geier M, Sailer C, Glieder A, Thallinger GG. Whole Genome Sequencing Analysis of Effects of CRISPR/Cas9 in Komagataella phaffii: A Budding Yeast in Distress. J Fungi (Basel) 2022; 8:jof8100992. [PMID: 36294556 PMCID: PMC9605565 DOI: 10.3390/jof8100992] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
The industrially important non-conventional yeast Komagataella phaffii suffers from low rates of homologous recombination, making site specific genetic engineering tedious. Therefore, genome editing using CRISPR/Cas represents a simple and efficient alternative. To characterize on- and off-target mutations caused by CRISPR/Cas9 followed by non-homologous end joining repair, we chose a diverse set of CRISPR/Cas targets and conducted whole genome sequencing on 146 CRISPR/Cas9 engineered single colonies. We compared the outcomes of single target CRISPR transformations to double target experiments. Furthermore, we examined the extent of possible large deletions by targeting a large genomic region, which is likely to be non-essential. The analysis of on-target mutations showed an unexpectedly high number of large deletions and chromosomal rearrangements at the CRISPR target loci. We also observed an increase of on-target structural variants in double target experiments as compared to single target experiments. Targeting of two loci within a putatively non-essential region led to a truncation of chromosome 3 at the target locus in multiple cases, causing the deletion of 20 genes and several ribosomal DNA repeats. The identified de novo off-target mutations were rare and randomly distributed, with no apparent connection to unspecific CRISPR/Cas9 off-target binding sites.
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Affiliation(s)
- Veronika Schusterbauer
- bisy GmbH, Wuenschendorf 292, 8200 Hofstaetten, Austria
- Institute of Biomedical Imaging, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
| | | | - Sarah Gangl
- bisy GmbH, Wuenschendorf 292, 8200 Hofstaetten, Austria
| | - Lisa Schenzle
- bisy GmbH, Wuenschendorf 292, 8200 Hofstaetten, Austria
| | | | - Martina Geier
- bisy GmbH, Wuenschendorf 292, 8200 Hofstaetten, Austria
| | - Christian Sailer
- Institute of Biomedical Informatics, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
| | - Anton Glieder
- bisy GmbH, Wuenschendorf 292, 8200 Hofstaetten, Austria
| | - Gerhard G. Thallinger
- Institute of Biomedical Informatics, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
- OMICS Center Graz, BioTechMed Graz, Stiftingtalstraße 24, 8010 Graz, Austria
- Correspondence: ; Tel.: +43-316-873-5343
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12
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Hanscom T, Woodward N, Batorsky R, Brown AJ, Roberts SA, McVey M. Characterization of sequence contexts that favor alternative end joining at Cas9-induced double-strand breaks. Nucleic Acids Res 2022; 50:7465-7478. [PMID: 35819195 PMCID: PMC9303309 DOI: 10.1093/nar/gkac575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Alternative end joining (alt-EJ) mechanisms, such as polymerase theta-mediated end joining, are increasingly recognized as important contributors to inaccurate double-strand break repair. We previously proposed an alt-EJ model whereby short DNA repeats near a double-strand break anneal to form secondary structures that prime limited DNA synthesis. The nascent DNA then pairs with microhomologous sequences on the other break end. This synthesis-dependent microhomology-mediated end joining (SD-MMEJ) explains many of the alt-EJ repair products recovered following I-SceI nuclease cutting in Drosophila. However, sequence-specific factors that influence SD-MMEJ repair remain to be fully characterized. Here, we expand the utility of the SD-MMEJ model through computational analysis of repair products at Cas9-induced double-strand breaks for 1100 different sequence contexts. We find evidence at single nucleotide resolution for sequence characteristics that drive successful SD-MMEJ repair. These include optimal primer repeat length, distance of repeats from the break, flexibility of DNA sequence between primer repeats, and positioning of microhomology templates relative to preferred primer repeats. In addition, we show that DNA polymerase theta is necessary for most SD-MMEJ repair at Cas9 breaks. The analysis described here includes a computational pipeline that can be utilized to characterize preferred mechanisms of alt-EJ repair in any sequence context.
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Affiliation(s)
- Terrence Hanscom
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Nicholas Woodward
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Rebecca Batorsky
- Data Intensive Studies Center, Tufts University, 177 College Ave, 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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13
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Huang J, Cook DE. The contribution of DNA repair pathways to genome editing and evolution in filamentous pathogens. FEMS Microbiol Rev 2022; 46:6638986. [PMID: 35810003 PMCID: PMC9779921 DOI: 10.1093/femsre/fuac035] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/29/2022] [Accepted: 07/06/2022] [Indexed: 01/09/2023] Open
Abstract
DNA double-strand breaks require repair or risk corrupting the language of life. To ensure genome integrity and viability, multiple DNA double-strand break repair pathways function in eukaryotes. Two such repair pathways, canonical non-homologous end joining and homologous recombination, have been extensively studied, while other pathways such as microhomology-mediated end joint and single-strand annealing, once thought to serve as back-ups, now appear to play a fundamental role in DNA repair. Here, we review the molecular details and hierarchy of these four DNA repair pathways, and where possible, a comparison for what is known between animal and fungal models. We address the factors contributing to break repair pathway choice, and aim to explore our understanding and knowledge gaps regarding mechanisms and regulation in filamentous pathogens. We additionally discuss how DNA double-strand break repair pathways influence genome engineering results, including unexpected mutation outcomes. Finally, we review the concept of biased genome evolution in filamentous pathogens, and provide a model, termed Biased Variation, that links DNA double-strand break repair pathways with properties of genome evolution. Despite our extensive knowledge for this universal process, there remain many unanswered questions, for which the answers may improve genome engineering and our understanding of genome evolution.
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Affiliation(s)
- Jun Huang
- Department of Plant Pathology, Kansas State University, 1712 Claflin Road, Throckmorton Hall, Manhattan, KS 66506, United States
| | - David E Cook
- Corresponding author: 1712 Claflin Road, 4004 Throckmorton Hall, Manhattan, KS 66502, United States. E-mail:
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14
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Tatman PD, Black JC. Extrachromosomal Circular DNA from TCGA Tumors Is Generated from Common Genomic Loci, Is Characterized by Self-Homology and DNA Motifs near Circle Breakpoints. Cancers (Basel) 2022; 14:cancers14092310. [PMID: 35565439 PMCID: PMC9101409 DOI: 10.3390/cancers14092310] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 02/06/2023] Open
Abstract
Extrachromosomal circular DNA has emerged as a frequent genomic alteration in tumors. High numbers of circular DNAs correspond to poor prognosis suggesting an important function in tumor biology. However, despite mounting evidence supporting the importance of circular DNA, little is known about their production, maintenance, or selection. To provide insight into these processes, we analyzed circular DNA elements computationally identified in 355 TCGA tumors spanning 22 tumor types. Circular DNAs originated from common genomic loci irrespective of cancer type. Genes found in circularized genomic regions were more likely to be expressed and were enriched in cancer-related pathways. Finally, in support of a model for circle generation through either a homology or microhomology-mediated process, circles exhibit homology near their breakpoint. These breakpoints are also enriched in specific DNA motifs. Our analysis supports a model where gene-containing circles emerge from common, highly transcribed regions through a homology-mediated process.
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15
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Ramsden DA, Carvajal-Garcia J, Gupta GP. Mechanism, cellular functions and cancer roles of polymerase-theta-mediated DNA end joining. Nat Rev Mol Cell Biol 2022; 23:125-140. [PMID: 34522048 DOI: 10.1038/s41580-021-00405-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 02/08/2023]
Abstract
Cellular pathways that repair chromosomal double-strand breaks (DSBs) have pivotal roles in cell growth, development and cancer. These DSB repair pathways have been the target of intensive investigation, but one pathway - alternative end joining (a-EJ) - has long resisted elucidation. In this Review, we highlight recent progress in our understanding of a-EJ, especially the assignment of DNA polymerase theta (Polθ) as the predominant mediator of a-EJ in most eukaryotes, and discuss a potential molecular mechanism by which Polθ-mediated end joining (TMEJ) occurs. We address possible cellular functions of TMEJ in resolving DSBs that are refractory to repair by non-homologous end joining (NHEJ), DSBs generated following replication fork collapse and DSBs present owing to stalling of repair by homologous recombination. We also discuss how these context-dependent cellular roles explain how TMEJ can both protect against and cause genome instability, and the emerging potential of Polθ as a therapeutic target in cancer.
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Affiliation(s)
- Dale A Ramsden
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Juan Carvajal-Garcia
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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16
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Fang SG, Xia TL, Fu JC, Li T, Zhong Q, Han F. BCL6-SPECC1L: A Novel Fusion Gene in Nasopharyngeal Carcinoma. Technol Cancer Res Treat 2022; 21:15330338221139981. [PMID: 36412101 PMCID: PMC9706053 DOI: 10.1177/15330338221139981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 10/28/2022] [Accepted: 11/02/2022] [Indexed: 07/30/2023] Open
Abstract
Background: Nasopharyngeal carcinomas (NPCs) are malignant tumors originating from the lining epithelium of the nasopharynx. Fusion genes have been confirmed to play important roles in the occurrence and development of various malignant tumors, but the role of fusion genes in NPC is poorly understood. We aimed to explore new fusion genes that promote the occurrence and development of NPC. Methods: RNA-seq was used to search for interchromosomal translocations in 18 NPC tissues. Polymerase chain reaction (PCR) and Sanger sequencing were applied to verify the presence of BCL6-SPECC1L (BS); quantitative PCR (qPCR) and Western blotting were used to measure the expression level of BCL-6 in NPC cells; MTT and in vivo tumorigenesis assays were applied to evaluate the cell proliferation ability; immunofluorescence assays were used to determine the cellular localization of BCL6 and BS; and a luciferase reporter assay was performed to evaluate the ability of BCL6 and BS to inhibit transcription. Results: BS was present in 5.34% (11/206) of primary NPC biopsies and 2.13% (1/47) of head and neck cancer biopsies. The expression of BCL6 was downregulated in NPC, and silencing of endogenous BCL6 promoted NPC cell proliferation in vitro. Overexpression of BCL6 but not BS inhibited the growth of NPC cells in vivo and in vitro. Mechanistically, BCL6 localized in the nucleus can inhibit the G1/S transition to suppress the growth of NPC cells. However, after the fusion of BCL6 and SPECC1L, the product cannot localize to the nucleus, and the transcriptional inhibitory function of BCL6 is abolished, eventually abolishing its tumor suppressor effect and leading to the development of NPC. Conclusion: BS is a novel fusion gene in NPC that may play an important role in the occurrence and development of this cancer. The clinical significance of the BS fusion gene needs further elucidation.
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Affiliation(s)
- Shuo-Gui Fang
- Department of Radiation Oncology, Sun Yat-sen University Cancer
Center, Guangzhou, Guangdong, China
- Department of Thoracic Surgery, Sun Yat-sen University Cancer
Center, Guangzhou, Guangdong, China
- State Key Laboratory of Oncology in South China, Guangzhou,
China
- Collaborative Innovation Center for Cancer Medicine, Guangzhou,
China
| | - Tian-Liang Xia
- State Key Laboratory of Oncology in South China, Guangzhou,
China
- Collaborative Innovation Center for Cancer Medicine, Guangzhou,
China
| | - Jian-Chang Fu
- Collaborative Innovation Center for Cancer Medicine, Guangzhou,
China
- Department of Pathology, Sun Yat-Sen University Cancer
Center, Guangzhou, China
| | - Tong Li
- Department of Cancer Prevention, Sun Yat-sen University Cancer
Center, Guangzhou, China
| | - Qian Zhong
- State Key Laboratory of Oncology in South China, Guangzhou,
China
| | - Fei Han
- Department of Radiation Oncology, Sun Yat-sen University Cancer
Center, Guangzhou, Guangdong, China
- State Key Laboratory of Oncology in South China, Guangzhou,
China
- Collaborative Innovation Center for Cancer Medicine, Guangzhou,
China
- Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and
Therapy, Guangzhou, China
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17
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Shaltz S, Jinks-Robertson S. Mutagenic repair of a ZFN-induced double-strand break in yeast: Effects of cleavage site sequence and spacer size. DNA Repair (Amst) 2021; 108:103228. [PMID: 34601383 DOI: 10.1016/j.dnarep.2021.103228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/17/2021] [Accepted: 09/14/2021] [Indexed: 11/27/2022]
Abstract
Double-strand breaks are repaired by error-free homologous recombination or by relatively error-prone pathways that directly join broken ends. Both types of repair have been extensively studied in Saccharomyces cerevisiae using enzymes HO or I-SceI, which create breaks with 4-nt 3' overhangs. In the current study, a galactose-regulated zinc-finger nuclease (ZFN) designed to cleave the Drosophila rosy locus was used to generate breaks with 4-nt 5' overhangs at out-of-frame cleavage sites inserted into the yeast LYS2 gene. Mutagenic repair was examined following selection of prototrophs on lysine-deficient medium containing galactose or surviving colonies on galactose-containing rich medium. Following cleavage of the original rosy spacer (ACGAAT), most Lys+ colonies contained 1- or 4-bp insertions at the cleavage site while most survivors had either a 2-bp insertion or a large deletion. Small insertions reflected nonhomologous end joining (NHEJ) and large deletions were the product of microhomology-mediated end joining (MMEJ). Changing the original ACGAAT spacer to either AGCAAT, ACGCGT or CTATTA altered the molecular features of NHEJ events as well as their frequency relative to MMEJ. Altering the optimal 6-bp spacer size between the zinc-finger protein binding sites to 5 bp or 7 bp eliminated the effect of continuous ZFN expression on survival, but Lys+ prototrophs were still generated. Analysis of Lys+ revertants after cleavage of the 5-bp spacer indicated that both the position and spacing of ZFN-generated nicks were variable. Results provide insight into effects of overhang sequence on mutagenic outcomes and demonstrate ZFN cleavage of 5- or 7-bp spacers in vivo.
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Affiliation(s)
- Samantha Shaltz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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18
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Sharma AB, Erasimus H, Pinto L, Caron MC, Gopaul D, Peterlini T, Neumann K, Nazarov PV, Fritah S, Klink B, Herold-Mende CC, Niclou SP, Pasero P, Calsou P, Masson JY, Britton S, Van Dyck E. XAB2 promotes Ku eviction from single-ended DNA double-strand breaks independently of the ATM kinase. Nucleic Acids Res 2021; 49:9906-9925. [PMID: 34500463 PMCID: PMC8464071 DOI: 10.1093/nar/gkab785] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/16/2021] [Accepted: 09/01/2021] [Indexed: 12/18/2022] Open
Abstract
Replication-associated single-ended DNA double-strand breaks (seDSBs) are repaired predominantly through RAD51-mediated homologous recombination (HR). Removal of the non-homologous end-joining (NHEJ) factor Ku from resected seDSB ends is crucial for HR. The coordinated actions of MRE11-CtIP nuclease activities orchestrated by ATM define one pathway for Ku eviction. Here, we identify the pre-mRNA splicing protein XAB2 as a factor required for resistance to seDSBs induced by the chemotherapeutic alkylator temozolomide. Moreover, we show that XAB2 prevents Ku retention and abortive HR at seDSBs induced by temozolomide and camptothecin, via a pathway that operates in parallel to the ATM-CtIP-MRE11 axis. Although XAB2 depletion preserved RAD51 focus formation, the resulting RAD51-ssDNA associations were unproductive, leading to increased NHEJ engagement in S/G2 and genetic instability. Overexpression of RAD51 or RAD52 rescued the XAB2 defects and XAB2 loss was synthetically lethal with RAD52 inhibition, providing potential perspectives in cancer therapy.
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Affiliation(s)
- Abhishek Bharadwaj Sharma
- DNA Repair and Chemoresistance Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg
| | - Hélène Erasimus
- DNA Repair and Chemoresistance Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg.,Faculty of Science, Technology and Communication, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Lia Pinto
- DNA Repair and Chemoresistance Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg.,Faculty of Science, Technology and Communication, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Marie-Christine Caron
- CHU de Québec Research Center, Oncology Division, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Diyavarshini Gopaul
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
| | - Thibaut Peterlini
- CHU de Québec Research Center, Oncology Division, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Katrin Neumann
- DNA Repair and Chemoresistance Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg
| | - Petr V Nazarov
- Quantitative Biology Unit, Multiomics Data Science Group, LIH, Luxembourg
| | - Sabrina Fritah
- NorLux Neuro-Oncology Laboratory, Department of Oncology, LIH, Luxembourg
| | - Barbara Klink
- National Center of Genetics, Laboratoire National de Santé, Dudelange, Luxembourg.,Functional Tumour Genetics Group, Department of Oncology, LIH, Luxembourg
| | | | - Simone P Niclou
- NorLux Neuro-Oncology Laboratory, Department of Oncology, LIH, Luxembourg.,Department of Biomedicine, University of Bergen, Norway
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
| | - Patrick Calsou
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France, Equipe Labellisée Ligue Nationale Contre le Cancer 2018
| | - Jean-Yves Masson
- CHU de Québec Research Center, Oncology Division, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Sébastien Britton
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France, Equipe Labellisée Ligue Nationale Contre le Cancer 2018
| | - Eric Van Dyck
- DNA Repair and Chemoresistance Group, Department of Oncology, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg
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19
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Ellis DA, Reyes-Martín F, Rodríguez-López M, Cotobal C, Sun XM, Saintain Q, Jeffares DC, Marguerat S, Tallada VA, Bähler J. R-loops and regulatory changes in chronologically ageing fission yeast cells drive non-random patterns of genome rearrangements. PLoS Genet 2021; 17:e1009784. [PMID: 34464389 PMCID: PMC8437301 DOI: 10.1371/journal.pgen.1009784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 09/13/2021] [Accepted: 08/18/2021] [Indexed: 12/03/2022] Open
Abstract
Aberrant repair of DNA double-strand breaks can recombine distant chromosomal breakpoints. Chromosomal rearrangements compromise genome function and are a hallmark of ageing. Rearrangements are challenging to detect in non-dividing cell populations, because they reflect individually rare, heterogeneous events. The genomic distribution of de novo rearrangements in non-dividing cells, and their dynamics during ageing, remain therefore poorly characterized. Studies of genomic instability during ageing have focussed on mitochondrial DNA, small genetic variants, or proliferating cells. To characterize genome rearrangements during cellular ageing in non-dividing cells, we interrogated a single diagnostic measure, DNA breakpoint junctions, using Schizosaccharomyces pombe as a model system. Aberrant DNA junctions that accumulated with age were associated with microhomology sequences and R-loops. Global hotspots for age-associated breakpoint formation were evident near telomeric genes and linked to remote breakpoints elsewhere in the genome, including the mitochondrial chromosome. Formation of breakpoint junctions at global hotspots was inhibited by the Sir2 histone deacetylase and might be triggered by an age-dependent de-repression of chromatin silencing. An unexpected mechanism of genomic instability may cause more local hotspots: age-associated reduction in an RNA-binding protein triggering R-loops at target loci. This result suggests that biological processes other than transcription or replication can drive genome rearrangements. Notably, we detected similar signatures of genome rearrangements that accumulated in old brain cells of humans. These findings provide insights into the unique patterns and possible mechanisms of genome rearrangements in non-dividing cells, which can be promoted by ageing-related changes in gene-regulatory proteins.
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Affiliation(s)
- David A. Ellis
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Félix Reyes-Martín
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - María Rodríguez-López
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Cristina Cotobal
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Xi-Ming Sun
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Quentin Saintain
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Daniel C. Jeffares
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Samuel Marguerat
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Víctor A. Tallada
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Jürg Bähler
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
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20
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Al-Zain AM, Symington LS. The dark side of homology-directed repair. DNA Repair (Amst) 2021; 106:103181. [PMID: 34311272 DOI: 10.1016/j.dnarep.2021.103181] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 10/20/2022]
Abstract
DNA double strand breaks (DSB) are cytotoxic lesions that can lead to genome rearrangements and genomic instability, which are hallmarks of cancer. The two main DSB repair pathways are non-homologous end joining and homologous recombination (HR). While HR is generally highly accurate, it has the potential for rearrangements that occur directly or through intermediates generated during the repair process. Whole genome sequencing of cancers has revealed numerous types of structural rearrangement signatures that are often indicative of repair mediated by sequence homology. However, it can be challenging to delineate repair mechanisms from sequence analysis of rearrangement end products from cancer genomes, or even model systems, because the same rearrangements can be generated by different pathways. Here, we review homology-directed repair pathways and their consequences. Exploring those pathways can lead to a greater understanding of rearrangements that occur in cancer cells.
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Affiliation(s)
- Amr M Al-Zain
- Program in Biological Sciences, Columbia University, New York, NY, 10027, United States; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, 10032, United States.
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21
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Xue C, Greene EC. DNA Repair Pathway Choices in CRISPR-Cas9-Mediated Genome Editing. Trends Genet 2021; 37:639-656. [PMID: 33896583 PMCID: PMC8187289 DOI: 10.1016/j.tig.2021.02.008] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 12/14/2022]
Abstract
Many clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9)-based genome editing technologies take advantage of Cas nucleases to induce DNA double-strand breaks (DSBs) at desired locations within a genome. Further processing of the DSBs by the cellular DSB repair machinery is then necessary to introduce desired mutations, sequence insertions, or gene deletions. Thus, the accuracy and efficiency of genome editing are influenced by the cellular DSB repair pathways. DSBs are themselves highly genotoxic lesions and as such cells have evolved multiple mechanisms for their repair. These repair pathways include homologous recombination (HR), classical nonhomologous end joining (cNHEJ), microhomology-mediated end joining (MMEJ) and single-strand annealing (SSA). In this review, we briefly highlight CRISPR-Cas9 and then describe the mechanisms of DSB repair. Finally, we summarize recent findings of factors that can influence the choice of DNA repair pathway in response to Cas9-induced DSBs.
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Affiliation(s)
- Chaoyou Xue
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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22
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Senataxin Ortholog Sen1 Limits DNA:RNA Hybrid Accumulation at DNA Double-Strand Breaks to Control End Resection and Repair Fidelity. Cell Rep 2021; 31:107603. [PMID: 32375052 DOI: 10.1016/j.celrep.2020.107603] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/07/2020] [Accepted: 04/10/2020] [Indexed: 11/20/2022] Open
Abstract
An important but still enigmatic function of DNA:RNA hybrids is their role in DNA double-strand break (DSB) repair. Here, we show that Sen1, the budding yeast ortholog of the human helicase Senataxin, is recruited at an HO endonuclease-induced DSB and limits the local accumulation of DNA:RNA hybrids. In the absence of Sen1, hybrid accumulation proximal to the DSB promotes increased binding of the Ku70-80 (KU) complex at the break site, mutagenic non-homologous end joining (NHEJ), micro-homology-mediated end joining (MMEJ), and chromosome translocations. We also show that homology-directed recombination (HDR) by gene conversion is mostly proficient in sen1 mutants after single DSB. However, in the absence of Sen1, DNA:RNA hybrids, Mre11, and Dna2 initiate resection through a non-canonical mechanism. We propose that this resection mechanism through local DNA:RNA hybrids acts as a backup to prime HDR when canonical pathways are altered, but at the expense of genome integrity.
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23
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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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24
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Van Vu T, Thi Hai Doan D, Kim J, Sung YW, Thi Tran M, Song YJ, Das S, Kim J. CRISPR/Cas-based precision genome editing via microhomology-mediated end joining. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:230-239. [PMID: 33047464 PMCID: PMC7868975 DOI: 10.1111/pbi.13490] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/11/2020] [Accepted: 10/03/2020] [Indexed: 05/05/2023]
Abstract
Gene editing and/or allele introgression with absolute precision and control appear to be the ultimate goals of genetic engineering. Precision genome editing in plants has been developed through various approaches, including oligonucleotide-directed mutagenesis (ODM), base editing, prime editing and especially homologous recombination (HR)-based gene targeting. With the advent of CRISPR/Cas for the targeted generation of DNA breaks (single-stranded breaks (SSBs) or double-stranded breaks (DSBs)), a substantial advancement in HR-mediated precise editing frequencies has been achieved. Nonetheless, further research needs to be performed for commercially viable applications of precise genome editing; hence, an alternative innovative method for genome editing may be required. Within this scope, we summarize recent progress regarding precision genome editing mediated by microhomology-mediated end joining (MMEJ) and discuss their potential applications in crop improvement.
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Affiliation(s)
- Tien Van Vu
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
- National Key Laboratory for Plant Cell BiotechnologyAgricultural Genetics InstituteKm 02, Pham Van Dong RoadCo Nhue 1, Bac Tu Liem, Hanoi11917Vietnam
| | - Duong Thi Hai Doan
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Jihae Kim
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Yeon Woo Sung
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Mil Thi Tran
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Young Jong Song
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Swati Das
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
| | - Jae‐Yean Kim
- Division of Applied Life Science (BK21 Plus Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinju 660‐701Republic of Korea
- Division of Life ScienceGyeongsang National University501 Jinju‐daeroJinju52828Republic of Korea
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25
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Choi JH, Lim YS, Kim MK, Bae SH. Analyses of DNA double-strand break repair pathways in tandem arrays of HXT genes of Saccharomyces cerevisiae. J Microbiol 2020; 58:957-966. [PMID: 33125670 DOI: 10.1007/s12275-020-0461-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 01/02/2023]
Abstract
Eukaryotic genomes contain numerous homologous repeat sequences including redundant genes with divergent homology that can be potential recombination targets. Recombination between divergent sequences is rare but poses a substantial threat to genome stability. The hexose transporter (HXT) gene family shares high sequence similarities at both protein and DNA levels, and some members are placed close together in tandem arrays. In this study, we show that spontaneous interstitial deletions occur at significantly high rates in HXT gene clusters, resulting in chimeric HXT sequences that contain a single junction point. We also observed that DNA double-strand breaks created between HXT genes produce primarily interstitial deletions, whereas internal cleavage of the HXT gene resulted in gene conversions as well as deletion products. Interestingly, interstitial deletions were less constrained by sequence divergence than gene conversion. Moreover, recombination-defective mutations differentially affected the survival frequency. Mutations that impair single-strand annealing (SSA) pathway greatly reduced the survival frequency by 10-1,000-fold, whereas disruption of Rad51-dependent homologous recombination exhibited only modest reduction. Our results indicate that recombination in the tandemly repeated HXT genes occurs primarily via SSA pathway.
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Affiliation(s)
- Ju-Hee Choi
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Ye-Seul Lim
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Min-Ku Kim
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Sung-Ho Bae
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea.
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26
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Polymerase δ promotes chromosomal rearrangements and imprecise double-strand break repair. Proc Natl Acad Sci U S A 2020; 117:27566-27577. [PMID: 33077594 DOI: 10.1073/pnas.2014176117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent studies have implicated DNA polymerases θ (Pol θ) and β (Pol β) as mediators of alternative nonhomologous end-joining (Alt-NHEJ) events, including chromosomal translocations. Here we identify subunits of the replicative DNA polymerase δ (Pol δ) as promoters of Alt-NHEJ that results in more extensive intrachromosomal mutations at a single double-strand break (DSB) and more frequent translocations between two DSBs. Depletion of the Pol δ accessory subunit POLD2 destabilizes the complex, resulting in degradation of both POLD1 and POLD3 in human cells. POLD2 depletion markedly reduces the frequency of translocations with sequence modifications but does not affect the frequency of translocations with exact joins. Using separation-of-function mutants, we show that both the DNA synthesis and exonuclease activities of the POLD1 subunit contribute to translocations. As described in yeast and unlike Pol θ, Pol δ also promotes homology-directed repair. Codepletion of POLD2 with 53BP1 nearly eliminates translocations. POLD1 and POLD2 each colocalize with phosphorylated H2AX at ionizing radiation-induced DSBs but not with 53BP1. Codepletion of POLD2 with either ligase 3 (LIG3) or ligase 4 (LIG4) does not further reduce translocation frequency compared to POLD2 depletion alone. Together, these data support a model in which Pol δ promotes Alt-NHEJ in human cells at DSBs, including translocations.
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27
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Hanscom T, McVey M. Regulation of Error-Prone DNA Double-Strand Break Repair and Its Impact on Genome Evolution. Cells 2020; 9:E1657. [PMID: 32660124 PMCID: PMC7407515 DOI: 10.3390/cells9071657] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022] Open
Abstract
Double-strand breaks are one of the most deleterious DNA lesions. Their repair via error-prone mechanisms can promote mutagenesis, loss of genetic information, and deregulation of the genome. These detrimental outcomes are significant drivers of human diseases, including many cancers. Mutagenic double-strand break repair also facilitates heritable genetic changes that drive organismal adaptation and evolution. In this review, we discuss the mechanisms of various error-prone DNA double-strand break repair processes and the cellular conditions that regulate them, with a focus on alternative end joining. We provide examples that illustrate how mutagenic double-strand break repair drives genome diversity and evolution. Finally, we discuss how error-prone break repair can be crucial to the induction and progression of diseases such as cancer.
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Affiliation(s)
| | - Mitch McVey
- Department. of Biology, Tufts University, Medford, MA 02155, USA;
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28
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Onaka AT, Su J, Katahira Y, Tang C, Zafar F, Aoki K, Kagawa W, Niki H, Iwasaki H, Nakagawa T. DNA replication machinery prevents Rad52-dependent single-strand annealing that leads to gross chromosomal rearrangements at centromeres. Commun Biol 2020; 3:202. [PMID: 32355220 PMCID: PMC7193609 DOI: 10.1038/s42003-020-0934-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 04/09/2020] [Indexed: 12/27/2022] Open
Abstract
Homologous recombination between repetitive sequences can lead to gross chromosomal rearrangements (GCRs). At fission yeast centromeres, Rad51-dependent conservative recombination predominantly occurs between inverted repeats, thereby suppressing formation of isochromosomes whose arms are mirror images. However, it is unclear how GCRs occur in the absence of Rad51 and how GCRs are prevented at centromeres. Here, we show that homology-mediated GCRs occur through Rad52-dependent single-strand annealing (SSA). The rad52-R45K mutation, which impairs SSA activity of Rad52 protein, dramatically reduces isochromosome formation in rad51 deletion cells. A ring-like complex Msh2-Msh3 and a structure-specific endonuclease Mus81 function in the Rad52-dependent GCR pathway. Remarkably, mutations in replication fork components, including DNA polymerase α and Swi1/Tof1/Timeless, change the balance between Rad51-dependent recombination and Rad52-dependent SSA at centromeres, increasing Rad52-dependent SSA that forms isochromosomes. Our results uncover a role of DNA replication machinery in the recombination pathway choice that prevents Rad52-dependent GCRs at centromeres.
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Affiliation(s)
- Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Chitose Laboratory Corporation, 2-13-3 Nogawa-honcho, Miyamae-ku, Kawasaki, Kanagawa, 216-0041, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Yasuhiro Katahira
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Department of Immunoregulation, Institute of Medical Science, Tokyo Medical University, 6-1-1 Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Crystal Tang
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Keita Aoki
- Microbial Physiology Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Wataru Kagawa
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo, 191-8506, Japan
| | - Hironori Niki
- Microbial Physiology Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
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29
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Epum EA, Mohan MJ, Ruppe NP, Friedman KL. Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. PLoS Genet 2020; 16:e1008608. [PMID: 32012161 PMCID: PMC7018233 DOI: 10.1371/journal.pgen.1008608] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 02/13/2020] [Accepted: 01/13/2020] [Indexed: 12/26/2022] Open
Abstract
DNA double-strand breaks (DSBs) are toxic forms of DNA damage that must be repaired to maintain genome integrity. Telomerase can act upon a DSB to create a de novo telomere, a process that interferes with normal repair and creates terminal deletions. We previously identified sequences in Saccharomyces cerevisiae (SiRTAs; Sites of Repair-associated Telomere Addition) that undergo unusually high frequencies of de novo telomere addition, even when the original chromosome break is several kilobases distal to the eventual site of telomerase action. Association of the single-stranded telomere binding protein Cdc13 with a SiRTA is required to stimulate de novo telomere addition. Because extensive resection must occur prior to Cdc13 binding, we utilized these sites to monitor the effect of proteins involved in homologous recombination. We find that telomere addition is significantly reduced in the absence of the Rad51 recombinase, while loss of Rad52, required for Rad51 nucleoprotein filament formation, has no effect. Deletion of RAD52 suppresses the defect of the rad51Δ strain, suggesting that Rad52 inhibits de novo telomere addition in the absence of Rad51. The ability of Rad51 to counteract this effect of Rad52 does not require DNA binding by Rad51, but does require interaction between the two proteins, while the inhibitory effect of Rad52 depends on its interaction with Replication Protein A (RPA). Intriguingly, the genetic interactions we report between RAD51 and RAD52 are similar to those previously observed in the context of checkpoint adaptation. Forced recruitment of Cdc13 fully restores telomere addition in the absence of Rad51, suggesting that Rad52, through its interaction with RPA-coated single-stranded DNA, inhibits the ability of Cdc13 to bind and stimulate telomere addition. Loss of the Rad51-Rad52 interaction also stimulates a subset of Rad52-dependent microhomology-mediated repair (MHMR) events, consistent with the known ability of Rad51 to prevent single-strand annealing. DNA double-strand breaks (DSBs) can lead to chromosome loss and rearrangement associated with cancer and genetic disease, so understanding how the cell coordinates multiple possible repair pathways is of critical importance. Telomerase is a ribonucleoprotein enzyme that uses an intrinsic RNA component as a template for the addition of highly repetitive, protective sequences (called telomeres) at normal chromosome ends. Rarely, telomerase acts upon a DSB to create a new or de novo telomere with resultant loss of sequences distal to the site of telomere addition. Here, we show that interactions between proteins with known roles during DSB repair modulate the probability of telomerase action at hotspots of de novo telomere addition in the yeast genome by influencing the association of Cdc13, a protein required for telomerase recruitment, with sites of telomere addition. Intriguingly, the same interactions that facilitate telomere addition prevent other types of rearrangements in response to chromosome breaks.
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Affiliation(s)
- Esther A. Epum
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Michael J. Mohan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Nicholas P. Ruppe
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine L. Friedman
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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30
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Deletions associated with stabilization of the Top1 cleavage complex in yeast are products of the nonhomologous end-joining pathway. Proc Natl Acad Sci U S A 2019; 116:22683-22691. [PMID: 31636207 PMCID: PMC6842612 DOI: 10.1073/pnas.1914081116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Topoisomerase I (Top1) resolves supercoils by nicking one DNA strand and facilitating religation after torsional stress has been relieved. During its reaction cycle, Top1 forms a covalent cleavage complex (Top1cc) with the nicked DNA, and this intermediate can be converted into a toxic double-strand break (DSB) during DNA replication. We previously reported that Top1cc trapping in yeast increases DSB-independent, short deletions at tandemly repeated sequences. In the current study, we report a type of DSB-dependent mutation associated with Top1cc stabilization: large deletions (median size, ∼100 bp) with little or no homology at deletion junctions. Genetic analyses demonstrated that Top1cc-dependent large deletions are products of the nonhomologous end-joining (NHEJ) pathway and require Top1cc removal from DNA ends. Furthermore, these events accumulated in quiescent cells, suggesting that the causative DSBs may arise outside the context of replication. We propose a model in which the ends of different, Top1-associated DSBs are joined via NHEJ, which results in deletion of the intervening sequence. These findings have important implications for understanding the mutagenic effects of chemotherapeutic drugs that stabilize the Top1cc.
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31
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Ferreira S, Dutreix M. DNA repair inhibitors to enhance radiotherapy: Progresses and limitations. Cancer Radiother 2019; 23:883-890. [PMID: 31615730 DOI: 10.1016/j.canrad.2019.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 08/29/2019] [Accepted: 08/31/2019] [Indexed: 02/08/2023]
Abstract
Radiotherapy is one of the most common form of treatment in oncology care. Indeed, radiotherapy proved to be very effective in treating a wide range of malignancies. Nevertheless, certain tumours are intrinsically radioresistant or may evolve to become radioresistant. Resistance to radiotherapy is often associated with dysregulated DNA damage response and repair. Recently, a number of strategies have been developed to improve radiotherapy efficacy by targeting the DNA damage response and repair pathways. Ongoing clinical trials showed the potential of some of these approaches in enhancing radiotherapy, but also highlighted the possible limitations. Here, we will describe (i) the main mechanisms involved in double-strand break repair; (ii) available strategies that target these DNA repair processes to improve radiotherapy and (iii) the clinical outcomes and challenges that have emerged so far.
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Affiliation(s)
- S Ferreira
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France
| | - M Dutreix
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France.
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32
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Frequency of DNA end joining in trans is not determined by the predamage spatial proximity of double-strand breaks in yeast. Proc Natl Acad Sci U S A 2019; 116:9481-9490. [PMID: 31019070 DOI: 10.1073/pnas.1818595116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
DNA double-strand breaks (DSBs) are serious genomic insults that can lead to chromosomal rearrangements if repaired incorrectly. To gain insight into the nuclear mechanisms contributing to these rearrangements, we developed an assay in yeast to measure cis (same site) vs. trans (different site) repair for the majority process of precise nonhomologous end joining (NHEJ). In the assay, the HO endonuclease gene is placed between two HO cut sites such that HO expression is self-terminated upon induction. We further placed an additional cut site in various genomic loci such that NHEJ in trans led to expression of a LEU2 reporter gene. Consistent with prior reports, cis NHEJ was more efficient than trans NHEJ. However, unlike homologous recombination, where spatial distance between a single DSB and donor locus was previously shown to correlate with repair efficiency, trans NHEJ frequency remained essentially constant regardless of the position of the two DSB loci, even when they were on the same chromosome or when two trans repair events were put in competition. Repair of similar DSBs via single-strand annealing of short terminal direct repeats showed substantially higher repair efficiency and trans repair frequency, but still without a strong correlation of trans repair to genomic position. Our results support a model in which yeast cells mobilize, and perhaps compartmentalize, multiple DSBs in a manner that no longer reflects the predamage position of two broken loci.
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33
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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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Pérez Di Giorgio JA, Lepage É, Tremblay-Belzile S, Truche S, Loubert-Hudon A, Brisson N. Transcription is a major driving force for plastid genome instability in Arabidopsis. PLoS One 2019; 14:e0214552. [PMID: 30943245 PMCID: PMC6447228 DOI: 10.1371/journal.pone.0214552] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/15/2019] [Indexed: 12/14/2022] Open
Abstract
Though it is an essential process, transcription can be a source of genomic instability. For instance, it may generate RNA:DNA hybrids as the nascent transcript hybridizes with the complementary DNA template. These hybrids, called R-loops, act as a major cause of replication fork stalling and DNA breaks. In this study, we show that lowering transcription and R-loop levels in plastids of Arabidopsis thaliana reduces DNA rearrangements and mitigates plastid genome instability phenotypes. This effect can be observed on a genome-wide scale, as the loss of the plastid sigma transcription factor SIG6 prevents DNA rearrangements by favoring conservative repair in the presence of ciprofloxacin-induced DNA damage or in the absence of plastid genome maintenance actors such as WHY1/WHY3, RECA1 and POLIB. Additionally, resolving R-loops by the expression of a plastid-targeted exogenous RNAse H1 produces similar results. We also show that highly-transcribed genes are more susceptible to DNA rearrangements, as increased transcription of the psbD operon by SIG5 correlates with more locus-specific rearrangements. The effect of transcription is not specific to Sigma factors, as decreased global transcription levels by mutation of heat-stress-induced factor HSP21, mutation of nuclear-encoded polymerase RPOTp, or treatment with transcription-inhibitor rifampicin all prevent the formation of plastid genome rearrangements, especially under induced DNA damage conditions.
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Affiliation(s)
| | - Étienne Lepage
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Samuel Tremblay-Belzile
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Sébastien Truche
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Audrey Loubert-Hudon
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Normand Brisson
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
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35
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Cooperation between non-essential DNA polymerases contributes to genome stability in Saccharomyces cerevisiae. DNA Repair (Amst) 2019; 76:40-49. [PMID: 30818168 DOI: 10.1016/j.dnarep.2019.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 11/21/2022]
Abstract
DNA polymerases influence genome stability through their involvement in DNA replication, response to DNA damage, and DNA repair processes. Saccharomyces cerevisiae possess four non-essential DNA polymerases, Pol λ, Pol η, Pol ζ, and Rev1, which have varying roles in genome stability. In order to assess the contribution of the non-essential DNA polymerases in genome stability, we analyzed the pol4Δ rev1Δ rev3Δ rad30Δ quadruple mutant in microhomology mediated repair, due to recent studies linking some of these DNA polymerases to this repair pathway. Our results suggest that the length and quality of microhomology influence both the overall efficiency of repair and the involvement of DNA polymerases. Furthermore, the non-essential DNA polymerases demonstrate overlapping and redundant functions when repairing double-strand breaks using short microhomologies containing mismatches. Then, we examined genome-wide mutation accumulation in the pol4Δ rev1Δ rev3Δ rad30Δ quadruple mutant compared to wild type cells. We found a significant decrease in the overall rate of mutation accumulation in the quadruple mutant cells compared to wildtype, but an increase in frameshift mutations and a shift towards transversion base-substitution with a preference for G:C to T:A or C:G. Thus, the non-essential DNA polymerases have an impact on the nature of the mutational spectrum. The sequence and functional homology shared between human and S. cerevisiae non-essential DNA polymerases suggest these DNA polymerases may have a similar role in human cells.
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36
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Prevalence of Mutation-Prone Microhomology-Mediated End Joining in a Chordate Lacking the c-NHEJ DNA Repair Pathway. Curr Biol 2018; 28:3337-3341.e4. [PMID: 30293719 DOI: 10.1016/j.cub.2018.08.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/18/2018] [Accepted: 08/21/2018] [Indexed: 12/20/2022]
Abstract
Classical non-homologous end joining (c-NHEJ), a fundamental pathway that repairs double-strand breaks in DNA, is almost universal in eukaryotes and involves multiple proteins highly conserved from yeast to human [1]. The genes encoding these proteins were not detected in the genome of Oikopleura dioica, a new model system of tunicate larvaceans known for its very compact and highly rearranged genome [2-4]. After showing their absence in the genomes of six other larvacean species, the present study examined how O. dioica oocytes and embryos repair double-strand DNA breaks (DSBs), using two approaches: the injection of linearized plasmids, which resulted in their rapid end joining, and a newly established CRISPR Cas9 technique. In both cases, end joining merged short microhomologous sequences surrounding the break (mainly 4 bp long), thus inducing deletions larger than for the tunicate ascidian Ciona intestinalis and human cells. A relatively high frequency of nucleotide insertions was also observed. Finally, a survey of genomic indels supports the involvement of microhomology-mediated repair in natural conditions. Overall, O. dioica repairs DSBs as other organisms do when their c-NHEJ pathway is experimentally rendered deficient, using another mode of end joining with the same effect as alternative NHEJ (a-NHEJ) or microhomology-mediated end joining (MMEJ) [5-7]. We discuss how the exceptional loss of c-NHEJ and its replacement by a more mutation-prone mechanism may have contributed to reshaping this genome and even been advantageous under pressure for genome compaction.
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Song X, Beck CR, Du R, Campbell IM, Coban-Akdemir Z, Gu S, Breman AM, Stankiewicz P, Ira G, Shaw CA, Lupski JR. Predicting human genes susceptible to genomic instability associated with Alu/ Alu-mediated rearrangements. Genome Res 2018; 28:1228-1242. [PMID: 29907612 PMCID: PMC6071635 DOI: 10.1101/gr.229401.117] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 06/06/2018] [Indexed: 12/14/2022]
Abstract
Alu elements, the short interspersed element numbering more than 1 million copies per human genome, can mediate the formation of copy number variants (CNVs) between substrate pairs. These Alu/Alu-mediated rearrangements (AAMRs) can result in pathogenic variants that cause diseases. To investigate the impact of AAMR on gene variation and human health, we first characterized Alus that are involved in mediating CNVs (CNV-Alus) and observed that these Alus tend to be evolutionarily younger. We then computationally generated, with the assistance of a supercomputer, a test data set consisting of 78 million Alu pairs and predicted ∼18% of them are potentially susceptible to AAMR. We further determined the relative risk of AAMR in 12,074 OMIM genes using the count of predicted CNV-Alu pairs and experimentally validated the predictions with 89 samples selected by correlating predicted hotspots with a database of CNVs identified by clinical chromosomal microarrays (CMAs) on the genomes of approximately 54,000 subjects. We fine-mapped 47 duplications, 40 deletions, and two complex rearrangements and examined a total of 52 breakpoint junctions of simple CNVs. Overall, 94% of the candidate breakpoints were at least partially Alu mediated. We successfully predicted all (100%) of Alu pairs that mediated deletions (n = 21) and achieved an 87% positive predictive value overall when including AAMR-generated deletions and duplications. We provided a tool, AluAluCNVpredictor, for assessing AAMR hotspots and their role in human disease. These results demonstrate the utility of our predictive model and provide insights into the genomic features and molecular mechanisms underlying AAMR.
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Affiliation(s)
- Xiaofei Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Christine R Beck
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Renqian Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Ian M Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Amy M Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Texas Children's Hospital, Houston, Texas 77030, USA
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Abstract
Prokaryotic type II adaptive immune systems have been developed into the versatile CRISPR technology, which has been widely applied in site-specific genome editing and has revolutionized biomedical research due to its superior efficiency and flexibility. Recent studies have greatly diversified CRISPR technologies by coupling it with various DNA repair mechanisms and targeting strategies. These new advances have significantly expanded the generation of genetically modified animal models, either by including species in which targeted genetic modification could not be achieved previously, or through introducing complex genetic modifications that take multiple steps and cost years to achieve using traditional methods. Herein, we review the recent developments and applications of CRISPR-based technology in generating various animal models, and discuss the everlasting impact of this new progress on biomedical research.
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Affiliation(s)
- Xun Ma
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Avery Sum-Yu Wong
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Hei-Yin Tam
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Samuel Yung-Kin Tsui
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Dittman Lai-Shun Chung
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Bo Feng
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China. .,Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Guangdong 510530, China.,SBS Core Laboratory, CUHK Shenzhen Research Institute, Shenzhen Guangdong 518057, China
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Spanjaard B, Hu B, Mitic N, Olivares-Chauvet P, Janjuha S, Ninov N, Junker JP. Simultaneous lineage tracing and cell-type identification using CRISPR-Cas9-induced genetic scars. Nat Biotechnol 2018; 36:469-473. [PMID: 29644996 PMCID: PMC5942543 DOI: 10.1038/nbt.4124] [Citation(s) in RCA: 319] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 03/15/2018] [Indexed: 12/12/2022]
Abstract
A key goal of developmental biology is to understand how a single cell transforms into a full-grown organism comprising many different cell types. Single-cell RNA-sequencing (scRNA-seq) is commonly used to identify cell types in a tissue or organ1. However, organizing the resulting taxonomy of cell types into lineage trees to understand developmental origin of cells remains challenging. Here we present LINNAEUS (LINeage tracing by Nuclease-Activated Editing of Ubiquitous Sequences)—a strategy for simultaneous lineage tracing and transcriptome profiling in thousands of single cells. By combining scRNA-seq with computational analysis of lineage barcodes, generated by genome editing of transgenic reporter genes, we reconstruct developmental lineage trees in zebrafish larvae, and in heart, liver, pancreas and telencephalon of adult fish. LINNAEUS provides a systematic approach for tracing the origin of novel cell types, or known cell types under different conditions.
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Affiliation(s)
- Bastiaan Spanjaard
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Bo Hu
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nina Mitic
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Pedro Olivares-Chauvet
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Sharan Janjuha
- DFG-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Nikolay Ninov
- DFG-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Jan Philipp Junker
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
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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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Kim SI, Matsumoto T, Kagawa H, Nakamura M, Hirohata R, Ueno A, Ohishi M, Sakuma T, Soga T, Yamamoto T, Woltjen K. Microhomology-assisted scarless genome editing in human iPSCs. Nat Commun 2018; 9:939. [PMID: 29507284 PMCID: PMC5838097 DOI: 10.1038/s41467-018-03044-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/16/2018] [Indexed: 12/26/2022] Open
Abstract
Gene-edited induced pluripotent stem cells (iPSCs) provide relevant isogenic human disease models in patient-specific or healthy genetic backgrounds. Towards this end, gene targeting using antibiotic selection along with engineered point mutations remains a reliable method to enrich edited cells. Nevertheless, integrated selection markers obstruct scarless transgene-free gene editing. Here, we present a method for scarless selection marker excision using engineered microhomology-mediated end joining (MMEJ). By overlapping the homology arms of standard donor vectors, short tandem microhomologies are generated flanking the selection marker. Unique CRISPR-Cas9 protospacer sequences nested between the selection marker and engineered microhomologies are cleaved after gene targeting, engaging MMEJ and scarless excision. Moreover, when point mutations are positioned unilaterally within engineered microhomologies, both mutant and normal isogenic clones are derived simultaneously. The utility and fidelity of our method is demonstrated in human iPSCs by editing the X-linked HPRT1 locus and biallelic modification of the autosomal APRT locus, eliciting disease-relevant metabolic phenotypes.
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Affiliation(s)
- Shin-Il Kim
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Tomoko Matsumoto
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Harunobu Kagawa
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Michiko Nakamura
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Ryoko Hirohata
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Ayano Ueno
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan
| | - Maki Ohishi
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Knut Woltjen
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan. .,Hakubi Center for Advanced Research, Kyoto University, Kyoto, 606-8501, Japan.
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42
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Baranes-Bachar K, Levy-Barda A, Oehler J, Reid DA, Soria-Bretones I, Voss TC, Chung D, Park Y, Liu C, Yoon JB, Li W, Dellaire G, Misteli T, Huertas P, Rothenberg E, Ramadan K, Ziv Y, Shiloh Y. The Ubiquitin E3/E4 Ligase UBE4A Adjusts Protein Ubiquitylation and Accumulation at Sites of DNA Damage, Facilitating Double-Strand Break Repair. Mol Cell 2018; 69:866-878.e7. [PMID: 29499138 PMCID: PMC6265044 DOI: 10.1016/j.molcel.2018.02.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 12/12/2017] [Accepted: 01/31/2018] [Indexed: 11/18/2022]
Abstract
Double-strand breaks (DSBs) are critical DNA lesions that robustly activate the elaborate DNA damage response (DDR) network. We identified a critical player in DDR fine-tuning: the E3/E4 ubiquitin ligase UBE4A. UBE4A's recruitment to sites of DNA damage is dependent on primary E3 ligases in the DDR and promotes enhancement and sustainment of K48- and K63-linked ubiquitin chains at these sites. This step is required for timely recruitment of the RAP80 and BRCA1 proteins and proper organization of RAP80- and BRCA1-associated protein complexes at DSB sites. This pathway is essential for optimal end resection at DSBs, and its abrogation leads to upregulation of the highly mutagenic alternative end-joining repair at the expense of error-free homologous recombination repair. Our data uncover a critical regulatory level in the DSB response and underscore the importance of fine-tuning the complex DDR network for accurate and balanced execution of DSB repair.
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Affiliation(s)
- Keren Baranes-Bachar
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adva Levy-Barda
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Judith Oehler
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Dylan A Reid
- Perlmutter NYU Cancer Center and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Isabel Soria-Bretones
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Ty C Voss
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Dudley Chung
- Departments of Pathology and Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Yoon Park
- Department of Biochemistry and Protein Network Research Center, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, Korea
| | - Chao Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jong-Bok Yoon
- Department of Biochemistry and Protein Network Research Center, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, Korea
| | - Wei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Graham Dellaire
- Departments of Pathology and Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Pablo Huertas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Eli Rothenberg
- Perlmutter NYU Cancer Center and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Kristijan Ramadan
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Yael Ziv
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Shiloh
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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43
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Gallagher DN, Haber JE. Repair of a Site-Specific DNA Cleavage: Old-School Lessons for Cas9-Mediated Gene Editing. ACS Chem Biol 2018; 13:397-405. [PMID: 29083855 DOI: 10.1021/acschembio.7b00760] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
CRISPR/Cas9-mediated gene editing may involve nonhomologous end-joining to create various insertion/deletions (indels) or may employ homologous recombination to modify precisely the target DNA sequence. Our understanding of these processes has been guided by earlier studies using other site-specific endonucleases, both in model organisms such as budding yeast and in mammalian cells. We briefly review what has been gleaned from such studies using the HO and I-SceI endonucleases and how these findings guide current gene editing strategies.
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Affiliation(s)
- Danielle N. Gallagher
- Rosenstiel Basic Medical
Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts 22454-9110, United States
| | - James E. Haber
- Rosenstiel Basic Medical
Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts 22454-9110, United States
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44
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TALEN-Induced Double-Strand Break Repair of CTG Trinucleotide Repeats. Cell Rep 2018; 22:2146-2159. [DOI: 10.1016/j.celrep.2018.01.083] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 12/19/2017] [Accepted: 01/25/2018] [Indexed: 11/19/2022] Open
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45
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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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46
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Mateos-Gomez PA, Kent T, Deng SK, McDevitt S, Kashkina E, Hoang TM, Pomerantz RT, Sfeir A. The helicase domain of Polθ counteracts RPA to promote alt-NHEJ. Nat Struct Mol Biol 2017; 24:1116-1123. [PMID: 29058711 PMCID: PMC6047744 DOI: 10.1038/nsmb.3494] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/22/2017] [Indexed: 12/15/2022]
Abstract
Mammalian polymerase theta (Polθ) is a multifunctional enzyme that promotes error-prone DNA repair by alternative nonhomologous end joining (alt-NHEJ). Here we present structure-function analyses that reveal that, in addition to the polymerase domain, Polθ-helicase activity plays a central role during double-strand break (DSB) repair. Our results show that the helicase domain promotes chromosomal translocations by alt-NHEJ in mouse embryonic stem cells and also suppresses CRISPR-Cas9- mediated gene targeting by homologous recombination (HR). In vitro assays demonstrate that Polθ-helicase activity facilitates the removal of RPA from resected DSBs to allow their annealing and subsequent joining by alt-NHEJ. Consistent with an antagonistic role for RPA during alt-NHEJ, inhibition of RPA1 enhances end joining and suppresses recombination. Taken together, our results reveal that the balance between HR and alt-NHEJ is controlled by opposing activities of Polθ and RPA, providing further insight into the regulation of repair-pathway choice in mammalian cells.
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Affiliation(s)
- Pedro A. Mateos-Gomez
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, USA
- Department of Cell Biology, New York University School of Medicine, New York, USA
| | - Tatiana Kent
- Temple University Lewis Katz School of Medicine, Philadelphia, USA
| | - Sarah K. Deng
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, USA
- Department of Cell Biology, New York University School of Medicine, New York, USA
| | - Shane McDevitt
- Temple University Lewis Katz School of Medicine, Philadelphia, USA
| | | | - Trung M. Hoang
- Temple University Lewis Katz School of Medicine, Philadelphia, USA
| | | | - Agnel Sfeir
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, USA
- Department of Cell Biology, New York University School of Medicine, New York, USA
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47
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Dutta A, Eckelmann B, Adhikari S, Ahmed KM, Sengupta S, Pandey A, Hegde PM, Tsai MS, Tainer JA, Weinfeld M, Hegde ML, Mitra S. Microhomology-mediated end joining is activated in irradiated human cells due to phosphorylation-dependent formation of the XRCC1 repair complex. Nucleic Acids Res 2017; 45:2585-2599. [PMID: 27994036 PMCID: PMC5389627 DOI: 10.1093/nar/gkw1262] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 12/15/2016] [Indexed: 02/06/2023] Open
Abstract
Microhomology-mediated end joining (MMEJ), an error-prone pathway for DNA double-strand break (DSB) repair, is implicated in genomic rearrangement and oncogenic transformation; however, its contribution to repair of radiation-induced DSBs has not been characterized. We used recircularization of a linearized plasmid with 3΄-P-blocked termini, mimicking those at X-ray-induced strand breaks, to recapitulate DSB repair via MMEJ or nonhomologous end-joining (NHEJ). Sequence analysis of the circularized plasmids allowed measurement of relative activity of MMEJ versus NHEJ. While we predictably observed NHEJ to be the predominant pathway for DSB repair in our assay, MMEJ was significantly enhanced in preirradiated cells, independent of their radiation-induced arrest in the G2/M phase. MMEJ activation was dependent on XRCC1 phosphorylation by casein kinase 2 (CK2), enhancing XRCC1's interaction with the end resection enzymes MRE11 and CtIP. Both endonuclease and exonuclease activities of MRE11 were required for MMEJ, as has been observed for homology-directed DSB repair (HDR). Furthermore, the XRCC1 co-immunoprecipitate complex (IP) displayed MMEJ activity in vitro, which was significantly elevated after irradiation. Our studies thus suggest that radiation-mediated enhancement of MMEJ in cells surviving radiation therapy may contribute to their radioresistance and could be therapeutically targeted.
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Affiliation(s)
- Arijit Dutta
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA.,Department of Biochemistry and Molecular Biology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
| | - Bradley Eckelmann
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA.,Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | | | - Kazi Mokim Ahmed
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Shiladitya Sengupta
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA.,Weill Cornell Medical College, New York, NY 10065, USA
| | - Arvind Pandey
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Pavana M Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Miaw-Sheue Tsai
- Department of Cell and Molecular Biology, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720, USA
| | - John A Tainer
- Department of Cell and Molecular Biology, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Michael Weinfeld
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Muralidhar L Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA.,Weill Cornell Medical College, New York, NY 10065, USA.,Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Sankar Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA.,Department of Biochemistry and Molecular Biology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA.,Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807, USA.,Weill Cornell Medical College, New York, NY 10065, USA
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48
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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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49
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Vu GTH, Cao HX, Reiss B, Schubert I. Deletion-bias in DNA double-strand break repair differentially contributes to plant genome shrinkage. THE NEW PHYTOLOGIST 2017; 214:1712-1721. [PMID: 28245065 DOI: 10.1111/nph.14490] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/22/2017] [Indexed: 06/06/2023]
Abstract
In order to prevent genome instability, cells need to be protected by a number of repair mechanisms, including DNA double-strand break (DSB) repair. The extent to which DSB repair, biased towards deletions or insertions, contributes to evolutionary diversification of genome size is still under debate. We analyzed mutation spectra in Arabidopsis thaliana and in barley (Hordeum vulgare) by PacBio sequencing of three DSB-targeted loci each, uncovering repair via gene conversion, single strand annealing (SSA) or nonhomologous end-joining (NHEJ). Furthermore, phylogenomic comparisons between A. thaliana and two related species were used to detect naturally occurring deletions during Arabidopsis evolution. Arabidopsis thaliana revealed significantly more and larger deletions after DSB repair than barley, and barley displayed more and larger insertions. Arabidopsis displayed a clear net loss of DNA after DSB repair, mainly via SSA and NHEJ. Barley revealed a very weak net loss of DNA, apparently due to less active break-end resection and easier copying of template sequences into breaks. Comparative phylogenomics revealed several footprints of SSA in the A. thaliana genome. Quantitative assessment of DNA gain and loss through DSB repair processes suggests deletion-biased DSB repair causing ongoing genome shrinking in A. thaliana, whereas genome size in barley remains nearly constant.
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Affiliation(s)
- Giang T H Vu
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Gatersleben, Germany
| | - Hieu X Cao
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Gatersleben, Germany
| | - Bernd Reiss
- Max Planck Institute for Plant Breeding Research, 50829, Köln, Germany
| | - Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Gatersleben, Germany
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50
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Sakofsky CJ, Malkova A. Break induced replication in eukaryotes: mechanisms, functions, and consequences. Crit Rev Biochem Mol Biol 2017; 52:395-413. [PMID: 28427283 DOI: 10.1080/10409238.2017.1314444] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Break-induced replication (BIR) is an important pathway specializing in repair of one-ended double-strand DNA breaks (DSBs). This type of DSB break typically arises at collapsed replication forks or at eroded telomeres. BIR initiates by invasion of a broken DNA end into a homologous template followed by initiation of DNA synthesis that can proceed for hundreds of kilobases. This synthesis is drastically different from S-phase replication in that instead of a replication fork, BIR proceeds via a migrating bubble and is associated with conservative inheritance of newly synthesized DNA. This unusual mode of DNA replication is responsible for frequent genetic instabilities associated with BIR, including hyper-mutagenesis, which can lead to the formation of mutation clusters, extensive loss of heterozygosity, chromosomal translocations, copy-number variations and complex genomic rearrangements. In addition to budding yeast experimental systems that were initially employed to investigate eukaryotic BIR, recent studies in different organisms including humans, have provided multiple examples of BIR initiated within different cellular contexts, including collapsed replication fork and telomere maintenance in the absence of telomerase. In addition, significant progress has been made towards understanding microhomology-mediated BIR (MMBIR) that can promote complex chromosomal rearrangements, including those associated with cancer and those leading to a number of neurological disorders in humans.
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Affiliation(s)
- Cynthia J Sakofsky
- a Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences , US National Institutes of Health , Research Triangle Park , NC , USA
| | - Anna Malkova
- b Department of Biology , University of Iowa , Iowa City , IA , USA
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