151
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Jain K, Wood EA, Romero ZJ, Cox MM. RecA-independent recombination: Dependence on the Escherichia coli RarA protein. Mol Microbiol 2021; 115:1122-1137. [PMID: 33247976 PMCID: PMC8160026 DOI: 10.1111/mmi.14655] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/29/2020] [Accepted: 11/20/2020] [Indexed: 11/30/2022]
Abstract
Most, but not all, homologous genetic recombination in bacteria is mediated by the RecA recombinase. The mechanistic origin of RecA-independent recombination has remained enigmatic. Here, we demonstrate that the RarA protein makes a major enzymatic contribution to RecA-independent recombination. In particular, RarA makes substantial contributions to intermolecular recombination and to recombination events involving relatively short (<200 bp) homologous sequences, where RecA-mediated recombination is inefficient. The effects are seen here in plasmid-based recombination assays and in vivo cloning processes. Vestigial levels of recombination remain even when both RecA and RarA are absent. Additional pathways for RecA-independent recombination, possibly mediated by helicases, are suppressed by exonucleases ExoI and RecJ. Translesion DNA polymerases may also contribute. Our results provide additional substance to a previous report of a functional overlap between RecA and RarA.
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Affiliation(s)
- Kanika Jain
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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152
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Kilgas S, Singh AN, Paillas S, Then CK, Torrecilla I, Nicholson J, Browning L, Vendrell I, Konietzny R, Kessler BM, Kiltie AE, Ramadan K. p97/VCP inhibition causes excessive MRE11-dependent DNA end resection promoting cell killing after ionizing radiation. Cell Rep 2021; 35:109153. [PMID: 34038735 PMCID: PMC8170441 DOI: 10.1016/j.celrep.2021.109153] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/16/2021] [Accepted: 04/28/2021] [Indexed: 01/01/2023] Open
Abstract
The ATPase p97 is a central component of the ubiquitin-proteasome degradation system. p97 uses its ATPase activity and co-factors to extract ubiquitinated substrates from different cellular locations, including DNA lesions, thereby regulating DNA repair pathway choice. Here, we find that p97 physically and functionally interacts with the MRE11-RAD50-NBS1 (MRN) complex on chromatin and that inactivation of p97 blocks the disassembly of the MRN complex from the sites of DNA damage upon ionizing radiation (IR). The inhibition of p97 function results in excessive 5'-DNA end resection mediated by MRE11 that leads to defective DNA repair and radiosensitivity. In addition, p97 inhibition by the specific small-molecule inhibitor CB-5083 increases tumor cell killing following IR both in vitro and in vivo. Mechanistically, this is mediated via increased MRE11 nuclease accumulation. This suggests that p97 inhibitors might be exploited to improve outcomes for radiotherapy patients.
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Affiliation(s)
- Susan Kilgas
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Abhay Narayan Singh
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Salome Paillas
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Chee-Kin Then
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Ignacio Torrecilla
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Judith Nicholson
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Lisa Browning
- Department of Cellular Pathology, Oxford University Hospitals, NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Iolanda Vendrell
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK; TDI Mass Spectrometry Laboratory, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Rebecca Konietzny
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Anne E Kiltie
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
| | - Kristijan Ramadan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
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153
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Repar J, Zahradka D, Sović I, Zahradka K. Characterization of gross genome rearrangements in Deinococcus radiodurans recA mutants. Sci Rep 2021; 11:10939. [PMID: 34035321 PMCID: PMC8149714 DOI: 10.1038/s41598-021-89173-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/21/2021] [Indexed: 02/04/2023] Open
Abstract
Genome stability in radioresistant bacterium Deinococcus radiodurans depends on RecA, the main bacterial recombinase. Without RecA, gross genome rearrangements occur during repair of DNA double-strand breaks. Long repeated (insertion) sequences have been identified as hot spots for ectopic recombination leading to genome rearrangements, and single-strand annealing (SSA) postulated to be the most likely mechanism involved in this process. Here, we have sequenced five isolates of D. radiodurans recA mutant carrying gross genome rearrangements to precisely characterize the rearrangements and to elucidate the underlying repair mechanism. The detected rearrangements consisted of large deletions in chromosome II in all the sequenced recA isolates. The mechanism behind these deletions clearly differs from the classical SSA; it utilized short (4-11 bp) repeats as opposed to insertion sequences or other long repeats. Moreover, it worked over larger linear DNA distances from those previously tested. Our data are most compatible with alternative end-joining, a recombination mechanism that operates in eukaryotes, but is also found in Escherichia coli. Additionally, despite the recA isolates being preselected for different rearrangement patterns, all identified deletions were found to overlap in a 35 kb genomic region. We weigh the evidence for mechanistic vs. adaptive reasons for this phenomenon.
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Affiliation(s)
- Jelena Repar
- grid.4905.80000 0004 0635 7705Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Davor Zahradka
- grid.4905.80000 0004 0635 7705Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Ivan Sović
- Digital BioLogic d.o.o, Ivanić-Grad, Croatia
| | - Ksenija Zahradka
- grid.4905.80000 0004 0635 7705Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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154
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Stok C, Kok Y, van den Tempel N, van Vugt MATM. Shaping the BRCAness mutational landscape by alternative double-strand break repair, replication stress and mitotic aberrancies. Nucleic Acids Res 2021; 49:4239-4257. [PMID: 33744950 PMCID: PMC8096281 DOI: 10.1093/nar/gkab151] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/18/2021] [Accepted: 03/05/2021] [Indexed: 12/16/2022] Open
Abstract
Tumours with mutations in the BRCA1/BRCA2 genes have impaired double-stranded DNA break repair, compromised replication fork protection and increased sensitivity to replication blocking agents, a phenotype collectively known as 'BRCAness'. Tumours with a BRCAness phenotype become dependent on alternative repair pathways that are error-prone and introduce specific patterns of somatic mutations across the genome. The increasing availability of next-generation sequencing data of tumour samples has enabled identification of distinct mutational signatures associated with BRCAness. These signatures reveal that alternative repair pathways, including Polymerase θ-mediated alternative end-joining and RAD52-mediated single strand annealing are active in BRCA1/2-deficient tumours, pointing towards potential therapeutic targets in these tumours. Additionally, insight into the mutations and consequences of unrepaired DNA lesions may also aid in the identification of BRCA-like tumours lacking BRCA1/BRCA2 gene inactivation. This is clinically relevant, as these tumours respond favourably to treatment with DNA-damaging agents, including PARP inhibitors or cisplatin, which have been successfully used to treat patients with BRCA1/2-defective tumours. In this review, we aim to provide insight in the origins of the mutational landscape associated with BRCAness by exploring the molecular biology of alternative DNA repair pathways, which may represent actionable therapeutic targets in in these cells.
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Affiliation(s)
- Colin Stok
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Yannick P Kok
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Nathalie van den Tempel
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Marcel A T M van Vugt
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
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155
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DNA double-strand break repair: Putting zinc fingers on the sore spot. Semin Cell Dev Biol 2021; 113:65-74. [DOI: 10.1016/j.semcdb.2020.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/22/2020] [Accepted: 09/07/2020] [Indexed: 12/15/2022]
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156
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Lim YS, Choi JH, Ahn KJ, Kim MK, Bae SH. Effects of the loss of mismatch repair genes on single-strand annealing between divergent sequences in Saccharomyces cerevisiae. J Microbiol 2021; 59:401-409. [PMID: 33779953 DOI: 10.1007/s12275-021-1076-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 10/21/2022]
Abstract
Eukaryotic genomes contain many duplicated genes closely located with each other, such as the hexose transporter (HXT) genes in Saccharomyces cerevisiae. They can potentially recombine via single-strand annealing (SSA) pathway. SSA between highly divergent sequences generates heteroduplex DNA intermediates with many mismatches, which can be corrected by mismatch repair (MMR), resulting in recombinant sequences with a single junction point. In this report, we demonstrate that SSA between HXT1 and HXT4 genes in MMR-deficient yeast cells produces recombinant genes with multiple-junctions resulting from alternating HXT1 and HXT4 tracts. The mutations in MMR genes had differential effects on SSA frequencies; msh6Δ mutation significantly stimulated SSA events, whereas msh2Δ and msh3Δ slightly suppressed it. We set up an assay that can identify a pair of recombinant genes derived from a single heteroduplex DNA. As a result, the recombinant genes with multiple-junctions were found to accompany genes with single-junctions. Based on the results presented here, a model was proposed to generate multiple-junctions in SSA pathway involving an alternative short-patch repair system.
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Affiliation(s)
- Ye-Seul Lim
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Ju-Hee Choi
- Department of Biological Sciences, College of Natural Science, Inha University, Incheon, 22212, Republic of Korea
| | - Kyu-Jin Ahn
- 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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157
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Patel PS, Algouneh A, Hakem R. Exploiting synthetic lethality to target BRCA1/2-deficient tumors: where we stand. Oncogene 2021; 40:3001-3014. [PMID: 33716297 DOI: 10.1038/s41388-021-01744-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/21/2021] [Accepted: 02/26/2021] [Indexed: 12/11/2022]
Abstract
The principle of synthetic lethality, which refers to the loss of viability resulting from the disruption of two genes, which, individually, do not cause lethality, has become an attractive target approach due to the development and clinical success of Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). In this review, we present the most recent findings on the use of PARPi in the clinic, which are currently approved for second-line therapy for advanced ovarian and breast cancer associated with mutations of BRCA1 or BRCA2 (BRCA1/2) genes. PARPi efficacy, however, appears to be limited by acquired and inherent resistance, highlighting the need for alternative and synergistic targets to eliminate these tumors. Here, we explore other identified synthetic lethal interactors of BRCA1/2, including DNA polymerase theta (POLQ), Fanconi anemia complementation group D2 (FANDC2), radiation sensitive 52 (RAD52), Flap structure-specific endonuclease 1 (FEN1), and apurinic/apyrimidinic endodeoxyribonuclease 2 (APE2), as well as other protein and nonprotein targets, for BRCA1/2-mutated cancers and their implications for future therapies. A wealth of information now exists for phenotypic and functional characterization of these novel synthetic lethal interactors of BRCA1/2, and leveraging these findings can pave the way for the development of new targeted therapies for patients suffering from these cancers.
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Affiliation(s)
- Parasvi S Patel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Arash Algouneh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Razq Hakem
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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158
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Deng HX, Zhai H, Shi Y, Liu G, Lowry J, Liu B, Ryan ÉB, Yan J, Yang Y, Zhang N, Yang Z, Liu E, Ma YC, Siddique T. Efficacy and long-term safety of CRISPR/Cas9 genome editing in the SOD1-linked mouse models of ALS. Commun Biol 2021; 4:396. [PMID: 33767386 PMCID: PMC7994668 DOI: 10.1038/s42003-021-01942-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/03/2021] [Indexed: 01/31/2023] Open
Abstract
CRISPR/Cas9-mediated genome editing provides potential for therapeutic development. Efficacy and long-term safety represent major concerns that remain to be adequately addressed in preclinical studies. Here we show that CRISPR/Cas9-mediated genome editing in two distinct SOD1-amyotrophic lateral sclerosis (ALS) transgenic mouse models prevented the development of ALS-like disease and pathology. The disease-linked transgene was effectively edited, with rare off-target editing events. We observed frequent large DNA deletions, ranging from a few hundred to several thousand base pairs. We determined that these large deletions were mediated by proximate identical sequences in Alu elements. No evidence of other diseases was observed beyond 2 years of age in these genome edited mice. Our data provide preclinical evidence of the efficacy and long-term safety of the CRISPR/Cas9 therapeutic approach. Moreover, the molecular mechanism of proximate identical sequences-mediated recombination provides mechanistic information to optimize therapeutic targeting design, and to avoid or minimize unintended and potentially deleterious recombination events.
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Affiliation(s)
- Han-Xiang Deng
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | - Hong Zhai
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yong Shi
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Guoxiang Liu
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jessica Lowry
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Bin Liu
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Éanna B Ryan
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jianhua Yan
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yi Yang
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Nigel Zhang
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Zhihua Yang
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Erdong Liu
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yongchao C Ma
- Departments of Pediatrics, Neurology and Physiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Teepu Siddique
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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159
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Morales ME, Kaul T, Walker J, Everett C, White T, Deininger P. Altered DNA repair creates novel Alu/Alu repeat-mediated deletions. Hum Mutat 2021; 42:600-613. [PMID: 33675284 PMCID: PMC8068675 DOI: 10.1002/humu.24193] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/25/2021] [Accepted: 02/24/2021] [Indexed: 12/21/2022]
Abstract
Alu elements are the most abundant source of nonallelic homology that influences genetic instability in the human genome. When there is a DNA double-stranded break, the Alu element's high copy number, moderate length and distance and mismatch between elements uniquely influence recombination processes. We utilize a reporter-gene assay to show the complex influence of Alu mismatches on Alu-related repeat-mediated deletions (RMDs). The Alu/Alu heteroduplex intermediate can result in a nonallelic homologous recombination (HR). Alternatively, the heteroduplex can result in various DNA breaks around the Alu elements caused by competing nucleases. These breaks can undergo Alt-nonhomologous end joining to cause deletions focused around the Alu elements. Formation of these heteroduplex intermediates is largely RAD52 dependent. Cells with low ERCC1 levels utilize more of these alternatives resolutions, while cells with MSH2 defects tend to have more RMDs with a specific increase in the HR events. Therefore, Alu elements are expected to create different forms of deletions in various cancers depending on a number of these DNA repair defects.
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Affiliation(s)
- Maria E Morales
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Tiffany Kaul
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - JaNiece Walker
- Department of Biology, Xavier University, New Orleans, Louisiana, USA
| | - Chelsea Everett
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Travis White
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Prescott Deininger
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Department of Epidemiology, Tulane University, New Orleans, Louisiana, USA
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160
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Toraason E, Horacek A, Clark C, Glover ML, Adler VL, Premkumar T, Salagean A, Cole F, Libuda DE. Meiotic DNA break repair can utilize homolog-independent chromatid templates in C. elegans. Curr Biol 2021; 31:1508-1514.e5. [PMID: 33740427 DOI: 10.1016/j.cub.2021.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023]
Abstract
During meiosis, the maintenance of genome integrity is critical for generating viable haploid gametes.1 In meiotic prophase I, double-strand DNA breaks (DSBs) are induced and a subset of these DSBs are repaired as interhomolog crossovers to ensure proper chromosome segregation. DSBs not resolved as crossovers with the homolog must be repaired by other pathways to ensure genome integrity.2 To determine if alternative repair templates can be engaged for meiotic DSB repair during oogenesis, we developed an assay to detect sister and/or intra-chromatid repair events at a defined DSB site during Caenorhabditis elegans meiosis. Using this assay, we directly demonstrate that the sister chromatid or the same DNA molecule can be engaged as a meiotic repair template for both crossover and noncrossover recombination, with noncrossover events being the predominant recombination outcome. We additionally find that the sister or intra-chromatid substrate is available as a recombination partner for DSBs induced throughout meiotic prophase I, including late prophase when the homolog is unavailable. Analysis of noncrossover conversion tract sequences reveals that DSBs are processed similarly throughout prophase I. We further present data indicating that the XPF-1 nuclease functions in late prophase to promote sister or intra-chromatid repair at steps of recombination following joint molecule processing. Despite its function in sister or intra-chromatid repair, we find that xpf-1 mutants do not exhibit severe defects in progeny viability following exposure to ionizing radiation. Overall, we propose that C. elegans XPF-1 may assist as an intersister or intrachromatid resolvase only in late prophase I.
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Affiliation(s)
- Erik Toraason
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Anna Horacek
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Cordell Clark
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Marissa L Glover
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Victoria L Adler
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Tolkappiyan Premkumar
- Department of Epigenetics and Molecular Carcinogenesis, MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX 78957, USA
| | - Alina Salagean
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA
| | - Francesca Cole
- Department of Epigenetics and Molecular Carcinogenesis, MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX 78957, USA
| | - Diana E Libuda
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA.
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161
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Mendez-Dorantes C, Tsai LJ, Jahanshir E, Lopezcolorado FW, Stark JM. BLM has Contrary Effects on Repeat-Mediated Deletions, based on the Distance of DNA DSBs to a Repeat and Repeat Divergence. Cell Rep 2021; 30:1342-1357.e4. [PMID: 32023454 PMCID: PMC7085117 DOI: 10.1016/j.celrep.2020.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/08/2019] [Accepted: 12/31/2019] [Indexed: 12/30/2022] Open
Abstract
Repeat-mediated deletions (RMDs) often involve repetitive elements (e.g., short interspersed elements) with sequence divergence that is separated by several kilobase pairs (kbps). We have examined RMDs induced by DNA double-strand breaks (DSBs) under varying conditions of repeat sequence divergence (identical versus 1% and 3% divergent) and DSB/repeat distance (16 bp–28.4 kbp). We find that the BLM helicase promotes RMDs with long DSB/repeat distances (e.g., 28.4 kbp), which is consistent with a role in extensive DSB end resection, because the resection nucleases EXO1 and DNA2 affect RMDs similarly to BLM. In contrast, BLM suppresses RMDs with sequence divergence and intermediate (e.g., 3.3 kbp) DSB/repeat distances, which supports a role in heteroduplex rejection. The role of BLM in heteroduplex rejection is not epistatic with MSH2 and is independent of the annealing factor RAD52. Accordingly, the role of BLM on RMDs is substantially affected by DSB/repeat distance and repeat sequence divergence. Mendez-Dorantes et al. identify the BLM helicase as a key regulator of repeat-mediated deletions (RMDs). BLM, EXO1, and DNA2 mediate RMDs with remarkably long DNA break/repeat distances. BLM suppresses RMDs with sequence divergence that is optimal with a long non-homologous tail and is independent of MSH2 and RAD52.
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Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - L Jillianne Tsai
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Eva Jahanshir
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | | | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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162
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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163
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021. [DOI: 10.3389/fcell.2021.640755 order by 1-- znbp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021. [DOI: 10.3389/fcell.2021.640755 order by 1-- azli] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund–Thomson syndrome (RTS), Baller–Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Lu H, Davis AJ. Human RecQ Helicases in DNA Double-Strand Break Repair. Front Cell Dev Biol 2021; 9:640755. [PMID: 33718381 PMCID: PMC7947261 DOI: 10.3389/fcell.2021.640755] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
RecQ DNA helicases are a conserved protein family found in bacteria, fungus, plants, and animals. These helicases play important roles in multiple cellular functions, including DNA replication, transcription, DNA repair, and telomere maintenance. Humans have five RecQ helicases: RECQL1, Bloom syndrome protein (BLM), Werner syndrome helicase (WRN), RECQL4, and RECQL5. Defects in BLM and WRN cause autosomal disorders: Bloom syndrome (BS) and Werner syndrome (WS), respectively. Mutations in RECQL4 are associated with three genetic disorders, Rothmund-Thomson syndrome (RTS), Baller-Gerold syndrome (BGS), and RAPADILINO syndrome. Although no genetic disorders have been reported due to loss of RECQL1 or RECQL5, dysfunction of either gene is associated with tumorigenesis. Multiple genetically independent pathways have evolved that mediate the repair of DNA double-strand break (DSB), and RecQ helicases play pivotal roles in each of them. The importance of DSB repair is supported by the observations that defective DSB repair can cause chromosomal aberrations, genomic instability, senescence, or cell death, which ultimately can lead to premature aging, neurodegeneration, or tumorigenesis. In this review, we will introduce the human RecQ helicase family, describe in detail their roles in DSB repair, and provide relevance between the dysfunction of RecQ helicases and human diseases.
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Affiliation(s)
- Huiming Lu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Anthony J. Davis
- Division of Molecular Radiation Biology, Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, United States
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173
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Single-Strand Annealing in Cancer. Int J Mol Sci 2021; 22:ijms22042167. [PMID: 33671579 PMCID: PMC7926775 DOI: 10.3390/ijms22042167] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/23/2022] Open
Abstract
DNA double-strand breaks (DSBs) are among the most serious forms of DNA damage. In humans, DSBs are repaired mainly by non-homologous end joining (NHEJ) and homologous recombination repair (HRR). Single-strand annealing (SSA), another DSB repair system, uses homologous repeats flanking a DSB to join DNA ends and is error-prone, as it removes DNA fragments between repeats along with one repeat. Many DNA deletions observed in cancer cells display homology at breakpoint junctions, suggesting the involvement of SSA. When multiple DSBs occur in different chromosomes, SSA may result in chromosomal translocations, essential in the pathogenesis of many cancers. Inhibition of RAD52 (RAD52 Homolog, DNA Repair Protein), the master regulator of SSA, results in decreased proliferation of BRCA1/2 (BRCA1/2 DNA Repair Associated)-deficient cells, occurring in many hereditary breast and ovarian cancer cases. Therefore, RAD52 may be targeted in synthetic lethality in cancer. SSA may modulate the response to platinum-based anticancer drugs and radiation. SSA may increase the efficacy of the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 (CRISPR associated 9) genome editing and reduce its off-target effect. Several basic problems associated with SSA, including its evolutionary role, interplay with HRR and NHEJ and should be addressed to better understand its role in cancer pathogenesis and therapy.
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174
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Stinson BM, Loparo JJ. Repair of DNA Double-Strand Breaks by the Nonhomologous End Joining Pathway. Annu Rev Biochem 2021; 90:137-164. [PMID: 33556282 DOI: 10.1146/annurev-biochem-080320-110356] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA double-strand breaks pose a serious threat to genome stability. In vertebrates, these breaks are predominantly repaired by nonhomologous end joining (NHEJ), which pairs DNA ends in a multiprotein synaptic complex to promote their direct ligation. NHEJ is a highly versatile pathway that uses an array of processing enzymes to modify damaged DNA ends and enable their ligation. The mechanisms of end synapsis and end processing have important implications for genome stability. Rapid and stable synapsis is necessary to limit chromosome translocations that result from the mispairing of DNA ends. Furthermore, end processing must be tightly regulated to minimize mutations at the break site. Here, we review our current mechanistic understanding of vertebrate NHEJ, with a particular focus on end synapsis and processing.
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Affiliation(s)
- Benjamin M Stinson
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
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175
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A Meta-Analysis of the Effects of High-LET Ionizing Radiations in Human Gene Expression. Life (Basel) 2021; 11:life11020115. [PMID: 33546472 PMCID: PMC7913660 DOI: 10.3390/life11020115] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/31/2021] [Accepted: 01/31/2021] [Indexed: 12/19/2022] Open
Abstract
The use of high linear energy transfer (LET) ionizing radiation (IR) is progressively being incorporated in radiation therapy due to its precise dose localization and high relative biological effectiveness. At the same time, these benefits of particle radiation become a high risk for astronauts in the case of inevitable cosmic radiation exposure. Nonetheless, DNA Damage Response (DDR) activated via complex DNA damage in healthy tissue, occurring from such types of radiation, may be instrumental in the induction of various chronic and late effects. An approach to elucidating the possible underlying mechanisms is studying alterations in gene expression. To this end, we identified differentially expressed genes (DEGs) in high Z and high energy (HZE) particle-, γ-ray- and X-ray-exposed healthy human tissues, utilizing microarray data available in public repositories. Differential gene expression analysis (DGEA) was conducted using the R programming language. Consequently, four separate meta-analyses were conducted, after DEG lists were grouped depending on radiation type, radiation dose and time of collection post-irradiation. To highlight the biological background of each meta-analysis group, functional enrichment analysis and biological network construction were conducted. For HZE particle exposure at 8–24 h post-irradiation, the most interesting finding is the variety of DNA repair mechanisms that were downregulated, a fact that is probably correlated with complex DNA damage formation. Simultaneously, after X-ray exposure during the same hours after irradiation, DNA repair mechanisms continue to take place. Finally, in a further comparison of low- and high-LET radiation effects, the most prominent result is that autophagy mechanisms seem to persist and that adaptive immune induction seems to be present. Such bioinformatics approaches may aid in obtaining an overview of the cellular response to high-LET particles. Understanding these response mechanisms can consequently aid in the development of countermeasures for future space missions and ameliorate heavy ion treatments.
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177
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Advances and Obstacles in Homology-Mediated Gene Editing of Hematopoietic Stem Cells. J Clin Med 2021; 10:jcm10030513. [PMID: 33535527 PMCID: PMC7867106 DOI: 10.3390/jcm10030513] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/14/2022] Open
Abstract
Homology-directed gene editing of hematopoietic stem and progenitor cells (HSPCs) is a promising strategy for the treatment of inherited blood disorders, obviating many of the limitations associated with viral vector-mediated gene therapies. The use of CRISPR/Cas9 or other programmable nucleases and improved methods of homology template delivery have enabled precise ex vivo gene editing. These transformative advances have also highlighted technical challenges to achieve high-efficiency gene editing in HSPCs for therapeutic applications. In this review, we discuss recent pre-clinical investigations utilizing homology-mediated gene editing in HSPCs and highlight various strategies to improve editing efficiency in these cells.
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178
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Jiang Y, Dong Y, Luo Y, Jiang S, Meng FL, Tan M, Li J, Zang Y. AMPK-mediated phosphorylation on 53BP1 promotes c-NHEJ. Cell Rep 2021; 34:108713. [PMID: 33596428 DOI: 10.1016/j.celrep.2021.108713] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/12/2020] [Accepted: 01/12/2021] [Indexed: 12/25/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is an energy sensor that plays roles in multiple biological processes beyond metabolism. Several studies have suggested that AMPK is involved in the DNA damage response (DDR), but the mechanisms remain unclear. Herein, we demonstrate that AMPK promotes classic non-homologous end joining (c-NHEJ) in double-strand break (DSB) repair through recruiting a key chromatin-based mediator named p53-binding protein 1 (53BP1), which facilitates the end joining of distal DNA ends during DDR. We find that the interaction of AMPK and 53BP1 spatially occurs under DSB stress. In the context of DSBs, AMPK directly phosphorylates 53BP1 at Ser1317 and promotes 53BP1 recruitment during DDR for an efficient c-NHEJ, thus maintaining genomic stability and diversity of the immune repertoire. Taken together, our study demonstrates that AMPK is a regulator of 53BP1 and controls c-NHEJ choice by phospho-regulation.
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Affiliation(s)
- Yuejing Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Ying Dong
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Yifeng Luo
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China; State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Shangwen Jiang
- Chemical Proteomics Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Fei-Long Meng
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China; State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Minjia Tan
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China; Chemical Proteomics Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jia Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China; Open Studio for Druggability Research of Marine Natural Products, Pilot National Laboratory for Marine Science and Technology (Qingdao), 1 Wenhai Road, Aoshanwei, Jimo, Qingdao 266237, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China.
| | - Yi Zang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China.
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179
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Rybin MJ, Ramic M, Ricciardi NR, Kapranov P, Wahlestedt C, Zeier Z. Emerging Technologies for Genome-Wide Profiling of DNA Breakage. Front Genet 2021; 11:610386. [PMID: 33584810 PMCID: PMC7873462 DOI: 10.3389/fgene.2020.610386] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/17/2020] [Indexed: 12/26/2022] Open
Abstract
Genome instability is associated with myriad human diseases and is a well-known feature of both cancer and neurodegenerative disease. Until recently, the ability to assess DNA damage-the principal driver of genome instability-was limited to relatively imprecise methods or restricted to studying predefined genomic regions. Recently, new techniques for detecting DNA double strand breaks (DSBs) and single strand breaks (SSBs) with next-generation sequencing on a genome-wide scale with single nucleotide resolution have emerged. With these new tools, efforts are underway to define the "breakome" in normal aging and disease. Here, we compare the relative strengths and weaknesses of these technologies and their potential application to studying neurodegenerative diseases.
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Affiliation(s)
- Matthew J Rybin
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States.,Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Melina Ramic
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States.,Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Natalie R Ricciardi
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States.,Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Philipp Kapranov
- Institute of Genomics, School of Biomedical Sciences, Huaqiao University, Xiamen, China
| | - Claes Wahlestedt
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States.,Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Zane Zeier
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States.,Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, United States
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180
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Yang Y, Wang T, Yu Q, Liu H, Xun L, Xia Y. The pathway of recombining short homologous ends in Escherichia coli revealed by the genetic study. Mol Microbiol 2021; 115:1309-1322. [PMID: 33372330 DOI: 10.1111/mmi.14677] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/17/2020] [Accepted: 12/23/2020] [Indexed: 11/30/2022]
Abstract
The recombination of short homologous ends in Escherichia coli has been known for 30 years, and it is often used for both site-directed mutagenesis and in vivo cloning. For cloning, a plasmid and target DNA fragments were converted into linear DNA fragments with short homologous ends, which are joined via recombination inside E. coli after transformation. Here this mechanism of joining homologous ends in E. coli was determined by a linearized plasmid with short homologous ends. Two 3'-5' exonucleases ExoIII and ExoX with nonprocessive activity digested linear dsDNA to generate 5' single-strand overhangs, which annealed with each other. The polymerase activity of DNA polymerase I (Pol I) was exclusively employed to fill in the gaps. The strand displacement activity and the 5'-3' exonuclease activity of Pol I were also required, likely to generate 5' phosphate termini for subsequent ligation. Ligase A (LigA) joined the nicks to finish the process. The model involving 5' single-stranded overhangs is different from established recombination pathways that all generate 3' single-stranded overhangs. This recombination is likely common in bacteria since the involved enzymes are ubiquitous.
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Affiliation(s)
- Yuqing Yang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China.,Institute of Marine Science and Technology, Shandong University, Qingdao, People's Republic of China
| | - Tianqi Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Qiaoli Yu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Huaiwei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Luying Xun
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China.,School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Yongzhen Xia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
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181
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Setton J, Reis-Filho JS, Powell SN. Homologous recombination deficiency: how genomic signatures are generated. Curr Opin Genet Dev 2021; 66:93-100. [PMID: 33477018 DOI: 10.1016/j.gde.2021.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/28/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
Cancer genomes harbor mutational and structural rearrangements that are jointly shaped by DNA damage and repair mechanisms. Accumulating evidence suggests that genetic alterations in DNA repair-defective tumors reflect the scars caused by the use of backup DNA repair mechanisms needed to maintain cellular viability. Detailed analysis of the patterns of mutations and structural rearrangements present in BRCA1/2-deficient tumors has allowed for the delineation of genomic signatures that reflect alternative repair with inactive homologous recombination (HR). Here we aim to summarize recent advances in the analysis of genomic signatures associated with HR-deficiency and examine recent studies that have shed light on the backup repair mechanisms responsible for genomic scarring in HR-deficient tumors.
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Affiliation(s)
- Jeremy Setton
- Dept. of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Jorge S Reis-Filho
- Dept. of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Simon N Powell
- Dept. of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Molecular Biology Program, Sloan Kettering Institute, New York, NY, United States.
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182
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Feng Y, Liu S, Chen R, Xie A. Target binding and residence: a new determinant of DNA double-strand break repair pathway choice in CRISPR/Cas9 genome editing. J Zhejiang Univ Sci B 2021; 22:73-86. [PMID: 33448189 PMCID: PMC7818014 DOI: 10.1631/jzus.b2000282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/24/2020] [Indexed: 12/26/2022]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) is widely used for targeted genomic and epigenomic modifications and imaging in cells and organisms, and holds tremendous promise in clinical applications. The efficiency and accuracy of the technology are partly determined by the target binding affinity and residence time of Cas9-single-guide RNA (sgRNA) at a given site. However, little attention has been paid to the effect of target binding affinity and residence duration on the repair of Cas9-induced DNA double-strand breaks (DSBs). We propose that the choice of DSB repair pathway may be altered by variation in the binding affinity and residence duration of Cas9-sgRNA at the cleaved target, contributing to significantly heterogeneous mutations in CRISPR/Cas9 genome editing. Here, we discuss the effect of Cas9-sgRNA target binding and residence on the choice of DSB repair pathway in CRISPR/Cas9 genome editing, and the opportunity this presents to optimize Cas9-based technology.
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Affiliation(s)
- Yili Feng
- Innovation Center for Minimally Invasive Technique and Device, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310019, China.
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou 310058, China.
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310029, China.
| | - Sicheng Liu
- Innovation Center for Minimally Invasive Technique and Device, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310019, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310029, China
| | - Ruodan Chen
- Innovation Center for Minimally Invasive Technique and Device, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310019, China
- Department of Biochemistry and Molecular Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310029, China
| | - Anyong Xie
- Innovation Center for Minimally Invasive Technique and Device, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310019, China.
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310029, China.
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183
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Goldberg GW, Spencer JM, Giganti DO, Camellato BR, Agmon N, Ichikawa DM, Boeke JD, Noyes MB. Engineered dual selection for directed evolution of SpCas9 PAM specificity. Nat Commun 2021; 12:349. [PMID: 33441553 PMCID: PMC7807044 DOI: 10.1038/s41467-020-20650-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 11/18/2020] [Indexed: 12/26/2022] Open
Abstract
The widely used Streptococcus pyogenes Cas9 (SpCas9) nuclease derives its DNA targeting specificity from protein-DNA contacts with protospacer adjacent motif (PAM) sequences, in addition to base-pairing interactions between its guide RNA and target DNA. Previous reports have established that the PAM specificity of SpCas9 can be altered via positive selection procedures for directed evolution or other protein engineering strategies. Here we exploit in vivo directed evolution systems that incorporate simultaneous positive and negative selection to evolve SpCas9 variants with commensurate or improved activity on NAG PAMs relative to wild type and reduced activity on NGG PAMs, particularly YGG PAMs. We also show that the PAM preferences of available evolutionary intermediates effectively determine whether similar counterselection PAMs elicit different selection stringencies, and demonstrate that negative selection can be specifically increased in a yeast selection system through the fusion of compensatory zinc fingers to SpCas9.
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Affiliation(s)
- Gregory W Goldberg
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA.
| | - Jeffrey M Spencer
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
| | - David O Giganti
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
| | - Brendan R Camellato
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
| | - Neta Agmon
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
- Neochromosome, Inc., Alexandria Center for Life Science, New York, NY, 10016, USA
| | - David M Ichikawa
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
| | - Jef D Boeke
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, 11201, USA
| | - Marcus B Noyes
- Institute for Systems Genetics, NYU Langone Health, New York, NY, 10016, USA.
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184
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Nickoloff JA, Taylor L, Sharma N, Kato TA. Exploiting DNA repair pathways for tumor sensitization, mitigation of resistance, and normal tissue protection in radiotherapy. CANCER DRUG RESISTANCE (ALHAMBRA, CALIF.) 2021; 4:244-263. [PMID: 34337349 PMCID: PMC8323830 DOI: 10.20517/cdr.2020.89] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
More than half of cancer patients are treated with radiotherapy, which kills tumor cells by directly and indirectly inducing DNA damage, including cytotoxic DNA double-strand breaks (DSBs). Tumor cells respond to these threats by activating a complex signaling network termed the DNA damage response (DDR). The DDR arrests the cell cycle, upregulates DNA repair, and triggers apoptosis when damage is excessive. The DDR signaling and DNA repair pathways are fertile terrain for therapeutic intervention. This review highlights strategies to improve therapeutic gain by targeting DDR and DNA repair pathways to radiosensitize tumor cells, overcome intrinsic and acquired tumor radioresistance, and protect normal tissue. Many biological and environmental factors determine tumor and normal cell responses to ionizing radiation and genotoxic chemotherapeutics. These include cell type and cell cycle phase distribution; tissue/tumor microenvironment and oxygen levels; DNA damage load and quality; DNA repair capacity; and susceptibility to apoptosis or other active or passive cell death pathways. We provide an overview of radiobiological parameters associated with X-ray, proton, and carbon ion radiotherapy; DNA repair and DNA damage signaling pathways; and other factors that regulate tumor and normal cell responses to radiation. We then focus on recent studies exploiting DSB repair pathways to enhance radiotherapy therapeutic gain.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
- Correspondence Address: Dr. Jac A. Nickoloff, Department of Environmental and Radiological Health Sciences, Colorado State University, 1681 Campus Delivery, Ft. Collins, CO 80523-1681, USA. E-mail:
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Takamitsu A. Kato
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
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185
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Wang J, Oh YT, Li Z, Dou J, Tang S, Wang X, Wang H, Takeda S, Wang Y. RAD52 Adjusts Repair of Single-Strand Breaks via Reducing DNA-Damage-Promoted XRCC1/LIG3α Co-localization. Cell Rep 2021; 34:108625. [PMID: 33440161 PMCID: PMC7872142 DOI: 10.1016/j.celrep.2020.108625] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/20/2020] [Accepted: 12/17/2020] [Indexed: 11/07/2022] Open
Abstract
Radiation sensitive 52 (RAD52) is an important factor for double-strand break repair (DSBR). However, deficiency in vertebrate/mammalian Rad52 has no apparent phenotype. The underlying mechanism remains elusive. Here, we report that RAD52 deficiency increased cell survival after camptothecin (CPT) treatment. CPT generates single-strand breaks (SSBs) that further convert to double-strand breaks (DSBs) if they are not repaired. RAD52 inhibits SSB repair (SSBR) through strong single-strand DNA (ssDNA) and/or poly(ADP-ribose) (PAR) binding affinity to reduce DNA-damage-promoted X-Ray Repair Cross Complementing 1 (XRCC1)/ligase IIIα (LIG3α) co-localization. The inhibitory effects of RAD52 on SSBR neutralize the role of RAD52 in DSBR, suggesting that RAD52 may maintain a balance between cell survival and genomic integrity. Furthermore, we demonstrate that blocking RAD52 oligomerization that disrupts RAD52’s DSBR, while retaining its ssDNA binding capacity that is required for RAD52’s inhibitory effects on SSBR, sensitizes cells to different DNA-damaging agents. This discovery provides guidance for developing efficient RAD52 inhibitors in cancer therapy. Wang et al. show that vertebrate/mammalian RAD52 promotes CPT-induced cell death via inhibition of PARP-mediated SSBR, which involves RAD52’s strong ssDNA/PAR binding affinity that reduces DNA-damage-promoted XRCC1-LIG3a interaction. Blocking of RAD52 oligomerization, while retaining the ssDNA binding capacity of RAD52, efficiently sensitizes cells to different DNA-damaging agents.
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Affiliation(s)
- Jian Wang
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - You-Take Oh
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Zhentian Li
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Juan Dou
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Siyuan Tang
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Xiang Wang
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Hongyan Wang
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Shunichi Takeda
- CREST Research Project, Radiation Genetics, Faculty of Medicine, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Ya Wang
- Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA.
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186
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Saha T, Sundaravinayagam D, Di Virgilio M. Charting a DNA Repair Roadmap for Immunoglobulin Class Switch Recombination. Trends Biochem Sci 2020; 46:184-199. [PMID: 33250286 DOI: 10.1016/j.tibs.2020.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/08/2020] [Accepted: 10/23/2020] [Indexed: 01/18/2023]
Abstract
Immunoglobulin (Ig) class switch recombination (CSR) is the process occurring in mature B cells that diversifies the effector component of antibody responses. CSR is initiated by the activity of the B cell-specific enzyme activation-induced cytidine deaminase (AID), which leads to the formation of programmed DNA double-strand breaks (DSBs) at the Ig heavy chain (Igh) locus. Mature B cells use a multilayered and complex regulatory framework to ensure that AID-induced DNA breaks are channeled into productive repair reactions leading to CSR, and to avoid aberrant repair events causing lymphomagenic chromosomal translocations. Here, we review the DNA repair pathways acting on AID-induced DSBs and their functional interplay, with a particular focus on the latest developments in their molecular composition and mechanistic regulation.
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Affiliation(s)
- Tannishtha Saha
- Laboratory of Genome Diversification and Integrity, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Devakumar Sundaravinayagam
- Laboratory of Genome Diversification and Integrity, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany.
| | - Michela Di Virgilio
- Laboratory of Genome Diversification and Integrity, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany; Charité-Universitätsmedizin Berlin, Berlin 10117, Germany.
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187
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The art of lineage tracing: From worm to human. Prog Neurobiol 2020; 199:101966. [PMID: 33249090 DOI: 10.1016/j.pneurobio.2020.101966] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 11/03/2020] [Accepted: 11/22/2020] [Indexed: 12/20/2022]
Abstract
Reconstructing the genealogy of every cell that makes up an organism remains a long-standing challenge in developmental biology. Besides its relevance for understanding the mechanisms underlying normal and pathological development, resolving the lineage origin of cell types will be crucial to create these types on-demand. Multiple strategies have been deployed towards the problem of lineage tracing, ranging from direct observation to sophisticated genetic approaches. Here we discuss the achievements and limitations of past and current technology. Finally, we speculate about the future of lineage tracing and how to reach the next milestones in the field.
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188
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Wang WJ, Li LY, Cui JW. Chromosome structural variation in tumorigenesis: mechanisms of formation and carcinogenesis. Epigenetics Chromatin 2020; 13:49. [PMID: 33168103 PMCID: PMC7654176 DOI: 10.1186/s13072-020-00371-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/29/2020] [Indexed: 12/23/2022] Open
Abstract
With the rapid development of next-generation sequencing technology, chromosome structural variation has gradually gained increased clinical significance in tumorigenesis. However, the molecular mechanism(s) underlying this structural variation remain poorly understood. A search of the literature shows that a three-dimensional chromatin state plays a vital role in inducing structural variation and in the gene expression profiles in tumorigenesis. Structural variants may result in changes in copy number or deletions of coding sequences, as well as the perturbation of structural chromatin features, especially topological domains, and disruption of interactions between genes and their regulatory elements. This review focuses recent work aiming at elucidating how structural variations develop and misregulate oncogenes and tumor suppressors, to provide general insights into tumor formation mechanisms and to provide potential targets for future anticancer therapies.
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Affiliation(s)
- Wen-Jun Wang
- Cancer Center, The First Hospital of Jilin University, Jilin University, Changchun, 130021 Jilin China
| | - Ling-Yu Li
- Cancer Center, The First Hospital of Jilin University, Jilin University, Changchun, 130021 Jilin China
| | - Jiu-Wei Cui
- Cancer Center, The First Hospital of Jilin University, Jilin University, Changchun, 130021 Jilin China
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189
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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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190
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CRISPR-mediated knock-in in the mouse embryo using long single stranded DNA donors synthesised by biotinylated PCR. Methods 2020; 191:3-14. [PMID: 33172594 DOI: 10.1016/j.ymeth.2020.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 09/21/2020] [Accepted: 10/18/2020] [Indexed: 12/26/2022] Open
Abstract
Successful gene knock-in by CRISPR-Cas9 in the mouse zygote requires three components; guideRNA, Cas9 protein and a suitable donor template, which usually comprises homology flanked insert sequence. Recently, long single stranded DNA (lssDNA) donors have emerged as a popular choice of DNA donor, outperforming dsDNA templates in terms of knock-in efficiency for gene tagging and generating conditional alleles. The generation of these donors can be achieved through several methods that may introduce errors in the sequence, result in poor yields, and contain dsDNA contamination. We have developed our own cost-effective lssDNA synthesis methodology that results in high purity, sequence verified, low contamination lssDNA donors. We provide a detailed methodology on the design and generation of such donors for gene tagging experiments and generating conditional alleles.
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191
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The molecular basis and disease relevance of non-homologous DNA end joining. Nat Rev Mol Cell Biol 2020; 21:765-781. [PMID: 33077885 DOI: 10.1038/s41580-020-00297-8] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2020] [Indexed: 12/26/2022]
Abstract
Non-homologous DNA end joining (NHEJ) is the predominant repair mechanism of any type of DNA double-strand break (DSB) during most of the cell cycle and is essential for the development of antigen receptors. Defects in NHEJ result in sensitivity to ionizing radiation and loss of lymphocytes. The most critical step of NHEJ is synapsis, or the juxtaposition of the two DNA ends of a DSB, because all subsequent steps rely on it. Recent findings show that, like the end processing step, synapsis can be achieved through several mechanisms. In this Review, we first discuss repair pathway choice between NHEJ and other DSB repair pathways. We then integrate recent insights into the mechanisms of NHEJ synapsis with updates on other steps of NHEJ, such as DNA end processing and ligation. Finally, we discuss NHEJ-related human diseases, including inherited disorders and neoplasia, which arise from rare failures at different NHEJ steps.
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192
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Nastasi C, Mannarino L, D’Incalci M. DNA Damage Response and Immune Defense. Int J Mol Sci 2020; 21:E7504. [PMID: 33053746 PMCID: PMC7588887 DOI: 10.3390/ijms21207504] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/08/2020] [Accepted: 10/10/2020] [Indexed: 02/07/2023] Open
Abstract
DNA damage is the cause of numerous human pathologies including cancer, premature aging, and chronic inflammatory conditions. The DNA damage response (DDR), in turn, coordinates DNA damage checkpoint activation and promotes the removal of DNA lesions. In recent years, several studies have shown how the DDR and the immune system are tightly connected, revealing an important crosstalk between the two of them. This interesting interplay has opened up new perspectives in clinical studies for immunological diseases as well as for cancer treatment. In this review, we provide an overview, from cellular to molecular pathways, on how DDR and the immune system communicate and share the crucial commitment of maintaining the genomic fitness.
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Affiliation(s)
- Claudia Nastasi
- Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156 Milan, Italy;
| | | | - Maurizio D’Incalci
- Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156 Milan, Italy;
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193
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Zahnreich S, Weber B, Rösch G, Schindler D, Schmidberger H. Compromised repair of radiation-induced DNA double-strand breaks in Fanconi anemia fibroblasts in G2. DNA Repair (Amst) 2020; 96:102992. [PMID: 33069004 DOI: 10.1016/j.dnarep.2020.102992] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/04/2020] [Accepted: 09/23/2020] [Indexed: 12/23/2022]
Abstract
Fanconi anemia (FA) is a rare chromosomal instability syndrome with various clinical features and high cancer incidence. Despite being a DNA repair disorder syndrome and a frequently observed clinical hypersensitivity of FA patients towards ionizing radiation, the experimental evidence regarding the efficiency of radiation-induced DNA double-strand break (DSB) repair in FA is very controversial. Here, we performed a thorough analysis of the repair of radiation-induced DSBs in G1 and G2 in FA fibroblasts of complementation groups A, C, D1 (BRCA2), D2, E, F, G and P (SLX4) in comparison to normal human lung and skin fibroblasts. γH2AX, 53BP1, or RPA foci quantification after X-irradiation was combined with cell cycle markers. Cytogenetic analyses were performed on first metaphases after irradiation in G1 and by premature chromosome condensation after exposure in G2. Furthermore, the role of canonical-NHEJ and alternative-NHEJ for the fidelity of the repair of radiation-induced DSBs was examined. In FA fibroblasts, DSB repair was normal in G1 but compromised and more error-prone in the slow repair component of G2 as suggested by higher yields of radiation-induced γH2AX and 53BP1 foci as well as chromatid exchanges. However, RPA foci quantification in G2 indicated proficiency for homology-directed repair of DSBs in FA except for FA D1 (BRCA2). In lung fibroblasts, DSB repair in G1 was conducted with normal kinetics but elevated chromosome exchanges compared to skin fibroblasts. The overall repair of radiation-induced DSBs and the formation of chromosome exchanges in normal and FA fibroblasts in G1 and G2 were governed by canonical-NHEJ with no contribution of alternative-NHEJ. Together, we show impaired repair of radiation-induced DSBs in various FA complementation groups in the slow repair component of G2 that might promote the formation of potentially oncogenic aberrations and clinical radiation hypersensitivity.
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Affiliation(s)
- Sebastian Zahnreich
- Department of Radiation Oncology and Radiation Therapy, University Medical Centre of the Johannes Gutenberg, University Mainz, Germany.
| | - Britta Weber
- Department of Radiation Oncology and Radiation Therapy, University Medical Centre of the Johannes Gutenberg, University Mainz, Germany
| | - Gundula Rösch
- Department of Radiation Oncology and Radiation Therapy, University Medical Centre of the Johannes Gutenberg, University Mainz, Germany
| | - Detlev Schindler
- Institute of Human Genetics, Julius-Maximilians-University, Würzburg, Germany
| | - Heinz Schmidberger
- Department of Radiation Oncology and Radiation Therapy, University Medical Centre of the Johannes Gutenberg, University Mainz, Germany
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194
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Pettitt SJ, Frankum JR, Punta M, Lise S, Alexander J, Chen Y, Yap TA, Haider S, Tutt ANJ, Lord CJ. Clinical BRCA1/2 Reversion Analysis Identifies Hotspot Mutations and Predicted Neoantigens Associated with Therapy Resistance. Cancer Discov 2020; 10:1475-1488. [PMID: 32699032 PMCID: PMC7611203 DOI: 10.1158/2159-8290.cd-19-1485] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/16/2020] [Accepted: 07/01/2020] [Indexed: 02/06/2023]
Abstract
Reversion mutations in BRCA1 or BRCA2 are associated with resistance to PARP inhibitors and platinum. To better understand the nature of these mutations, we collated, codified, and analyzed more than 300 reversions. This identified reversion "hotspots" and "deserts" in regions encoding the N and C terminus, respectively, of BRCA2, suggesting that pathogenic mutations in these regions may be at higher or lower risk of reversion. Missense and splice-site pathogenic mutations in BRCA1/2 also appeared less likely to revert than truncating mutations. Most reversions were <100 bp deletions. Although many deletions exhibited microhomology, this was not universal, suggesting that multiple DNA-repair processes cause reversion. Finally, we found that many reversions were predicted to encode immunogenic neopeptides, suggesting a route to the treatment of reverted disease. As well as providing a freely available database for the collation of future reversion cases, these observations have implications for how drug resistance might be managed in BRCA-mutant cancers. SIGNIFICANCE: Reversion mutations in BRCA genes are a major cause of clinical platinum and PARP inhibitor resistance. This analysis of all reported clinical reversions suggests that the position of BRCA2 mutations affects the risk of reversion. Many reversions are also predicted to encode tumor neoantigens, providing a potential route to targeting resistance.This article is highlighted in the In This Issue feature, p. 1426.
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Affiliation(s)
- Stephen J Pettitt
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Jessica R Frankum
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Marco Punta
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, United Kingdom
| | - Stefano Lise
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, United Kingdom
| | - John Alexander
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Yi Chen
- Scientific Computing Team, The Institute of Cancer Research, London, United Kingdom
| | - Timothy A Yap
- The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Syed Haider
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Andrew N J Tutt
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Christopher J Lord
- The CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom.
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, United Kingdom
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195
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Lodovichi S, Cervelli T, Pellicioli A, Galli A. Inhibition of DNA Repair in Cancer Therapy: Toward a Multi-Target Approach. Int J Mol Sci 2020; 21:E6684. [PMID: 32932697 PMCID: PMC7554826 DOI: 10.3390/ijms21186684] [Citation(s) in RCA: 8] [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: 08/04/2020] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022] Open
Abstract
Alterations in DNA repair pathways are one of the main drivers of cancer insurgence. Nevertheless, cancer cells are more susceptible to DNA damage than normal cells and they rely on specific functional repair pathways to survive. Thanks to advances in genome sequencing, we now have a better idea of which genes are mutated in specific cancers and this prompted the development of inhibitors targeting DNA repair players involved in pathways essential for cancer cells survival. Currently, the pivotal concept is that combining the inhibition of mechanisms on which cancer cells viability depends is the most promising way to treat tumorigenesis. Numerous inhibitors have been developed and for many of them, efficacy has been demonstrated either alone or in combination with chemo or radiotherapy. In this review, we will analyze the principal pathways involved in cell cycle checkpoint and DNA repair focusing on how their alterations could predispose to cancer, then we will explore the inhibitors developed or in development specifically targeting different proteins involved in each pathway, underscoring the rationale behind their usage and how their combination and/or exploitation as adjuvants to classic therapies could help in patients clinical outcome.
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Affiliation(s)
- Samuele Lodovichi
- Bioscience Department, University of Milan, Via Celoria 26, 20131 Milan, Italy;
| | - Tiziana Cervelli
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy;
| | - Achille Pellicioli
- Bioscience Department, University of Milan, Via Celoria 26, 20131 Milan, Italy;
| | - Alvaro Galli
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy;
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196
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Yang H, Ren S, Yu S, Pan H, Li T, Ge S, Zhang J, Xia N. Methods Favoring Homology-Directed Repair Choice in Response to CRISPR/Cas9 Induced-Double Strand Breaks. Int J Mol Sci 2020; 21:E6461. [PMID: 32899704 PMCID: PMC7555059 DOI: 10.3390/ijms21186461] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/20/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022] Open
Abstract
Precise gene editing is-or will soon be-in clinical use for several diseases, and more applications are under development. The programmable nuclease Cas9, directed by a single-guide RNA (sgRNA), can introduce double-strand breaks (DSBs) in target sites of genomic DNA, which constitutes the initial step of gene editing using this novel technology. In mammals, two pathways dominate the repair of the DSBs-nonhomologous end joining (NHEJ) and homology-directed repair (HDR)-and the outcome of gene editing mainly depends on the choice between these two repair pathways. Although HDR is attractive for its high fidelity, the choice of repair pathway is biased in a biological context. Mammalian cells preferentially employ NHEJ over HDR through several mechanisms: NHEJ is active throughout the cell cycle, whereas HDR is restricted to S/G2 phases; NHEJ is faster than HDR; and NHEJ suppresses the HDR process. This suggests that definitive control of outcome of the programmed DNA lesioning could be achieved through manipulating the choice of cellular repair pathway. In this review, we summarize the DSB repair pathways, the mechanisms involved in choice selection based on DNA resection, and make progress in the research investigating strategies that favor Cas9-mediated HDR based on the manipulation of repair pathway choice to increase the frequency of HDR in mammalian cells. The remaining problems in improving HDR efficiency are also discussed. This review should facilitate the development of CRISPR/Cas9 technology to achieve more precise gene editing.
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Affiliation(s)
| | | | | | | | - Tingdong Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Disease, Collaborative Innovation Centers of Biological Products, School of Public Health, Xiamen University, Xiamen 361102, China; (H.Y.); (S.R.); (S.Y.); (H.P.); (J.Z.); (N.X.)
| | - Shengxiang Ge
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Disease, Collaborative Innovation Centers of Biological Products, School of Public Health, Xiamen University, Xiamen 361102, China; (H.Y.); (S.R.); (S.Y.); (H.P.); (J.Z.); (N.X.)
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197
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Modulation of DNA double-strand break repair as a strategy to improve precise genome editing. Oncogene 2020; 39:6393-6405. [PMID: 32884115 DOI: 10.1038/s41388-020-01445-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 12/11/2022]
Abstract
In the present day, it is possible to incorporate targeted mutations or replace a gene using genome editing techniques such as customisable CRISPR/Cas9 system. Although induction of DNA double-strand breaks (DSBs) by genome editing tools can be repaired by both non-homologous end joining (NHEJ) and homologous recombination (HR), the skewness of the former pathway in human and other mammals normally result in imprecise repair. Scientists working at the crossroads of DNA repair and genome editing have devised new strategies for using a specific pathway to their advantage. Refinement in the efficiency of precise gene editing was witnessed upon downregulation of NHEJ by knockdown or using small molecule inhibitors on one hand, and upregulation of HR proteins and addition of HR stimulators, other hand. The exploitation of cell cycle phase differences together with appropriate donor DNA length/sequence and small molecules has provided further improvement in precise genome editing. The present article reviews the mechanisms of improving the efficiency of precise genome editing in several model organisms and in clinics.
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198
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Howard SM, Ceppi I, Anand R, Geiger R, Cejka P. The internal region of CtIP negatively regulates DNA end resection. Nucleic Acids Res 2020; 48:5485-5498. [PMID: 32347940 PMCID: PMC7261161 DOI: 10.1093/nar/gkaa273] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 04/05/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022] Open
Abstract
DNA double-strand breaks are repaired by end-joining or homologous recombination. A key-committing step of recombination is DNA end resection. In resection, phosphorylated CtIP first promotes the endonuclease of MRE11-RAD50-NBS1 (MRN). Subsequently, CtIP also stimulates the WRN/BLM-DNA2 pathway, coordinating thus both short and long-range resection. The structure of CtIP differs from its orthologues in yeast, as it contains a large internal unstructured region. Here, we conducted a domain analysis of CtIP to define the function of the internal region in DNA end resection. We found that residues 350-600 were entirely dispensable for resection in vitro. A mutant lacking these residues was unexpectedly more efficient than full-length CtIP in DNA end resection and homologous recombination in vivo, and consequently conferred resistance to lesions induced by the topoisomerase poison camptothecin, which require high MRN-CtIP-dependent resection activity for repair. This suggested that the internal CtIP region, further mapped to residues 550-600, may mediate a negative regulatory function to prevent over resection in vivo. The CtIP internal deletion mutant exhibited sensitivity to other DNA-damaging drugs, showing that upregulated resection may be instead toxic under different conditions. These experiments together identify a region within the central CtIP domain that negatively regulates DNA end resection.
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Affiliation(s)
- Sean Michael Howard
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Bellinzona, Switzerland
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Bellinzona, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland
| | - Roopesh Anand
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Bellinzona, Switzerland
| | - Roger Geiger
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Bellinzona, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Bellinzona, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland
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199
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Balzano E, Giunta S. Centromeres under Pressure: Evolutionary Innovation in Conflict with Conserved Function. Genes (Basel) 2020; 11:E912. [PMID: 32784998 PMCID: PMC7463522 DOI: 10.3390/genes11080912] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/22/2022] Open
Abstract
Centromeres are essential genetic elements that enable spindle microtubule attachment for chromosome segregation during mitosis and meiosis. While this function is preserved across species, centromeres display an array of dynamic features, including: (1) rapidly evolving DNA; (2) wide evolutionary diversity in size, shape and organization; (3) evidence of mutational processes to generate homogenized repetitive arrays that characterize centromeres in several species; (4) tolerance to changes in position, as in the case of neocentromeres; and (5) intrinsic fragility derived by sequence composition and secondary DNA structures. Centromere drive underlies rapid centromere DNA evolution due to the "selfish" pursuit to bias meiotic transmission and promote the propagation of stronger centromeres. Yet, the origins of other dynamic features of centromeres remain unclear. Here, we review our current understanding of centromere evolution and plasticity. We also detail the mutagenic processes proposed to shape the divergent genetic nature of centromeres. Changes to centromeres are not simply evolutionary relics, but ongoing shifts that on one side promote centromere flexibility, but on the other can undermine centromere integrity and function with potential pathological implications such as genome instability.
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Affiliation(s)
- Elisa Balzano
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, 00185 Roma, Italy;
| | - Simona Giunta
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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200
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Xu Y, Lin Y, Luo Y, Yang Y, Long B, Fang Z, Liu L, Zhang J, Zhang X. RAD52 aptamer regulates DNA damage repair and STAT3 in BRCA1/BRCA2‑deficient human acute myeloid leukemia. Oncol Rep 2020; 44:1455-1466. [PMID: 32945515 PMCID: PMC7448423 DOI: 10.3892/or.2020.7723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
RAD52 (Radiation sensitive 52) is a key factor in DNA damage repair (DDR) bypass, which participates in single-strand annealing (SSA) after DNA damage end excision, while breast cancer type 1 susceptibility protein (BRCA1)/breast cancer type 2 susceptibility protein (BRCA2) play critical roles in homologous recombination (HR) repair. The present study aimed to determine whether RAD52-induced regulation of repair bypass occurs in acute myeloid leukemia (AML) cells and to explore the underlying mechanism. Herein, we applied an RAD52 aptamer to AML cells with downregulated BRCA1/2. RAD52 aptamer inhibited AML cell proliferation detected by cell counting, promoted cell apoptosis obtained by flow cytometry, and suppressed DNA damage repair behavior measured by comet assay and flow cytometry, after drug intervention during low expression of BRCA1/2. During this process, DDR-related cell cycle checkpoint proteins were activated, and the cells were continuously arrested in the S/G2 phase, which affected the cell damage repair process. Concurrently, the expression levels of apoptosis-related proteins were also altered. Furthermore, the expression of STAT3 and p-STAT3 was downregulated by the RAD52 aptamer, suggesting that RAD52 affects the STAT3 signaling pathway. In summary, we present a possible role for RAD52 in DDR of BRCA1/2-deficient AML cells that involves the STAT3 signaling pathway.
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Affiliation(s)
- Yichuan Xu
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Yansi Lin
- Department of General Medicine, Sun Yat‑sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Yuxuan Luo
- Department of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China
| | - Yanling Yang
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Bing Long
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Zhigang Fang
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Lingling Liu
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Jingwen Zhang
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
| | - Xiangzhong Zhang
- Department of Hematology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China
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