1
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Sasaki M, Kobayashi T. Transcription near arrested DNA replication forks triggers ribosomal DNA copy number changes. Nucleic Acids Res 2025; 53:gkaf014. [PMID: 39876709 PMCID: PMC11760980 DOI: 10.1093/nar/gkaf014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 12/29/2024] [Accepted: 01/08/2025] [Indexed: 01/30/2025] Open
Abstract
DNA copy number changes via chromosomal rearrangements or the production of extrachromosomal circular DNA. Here, we demonstrate that the histone deacetylase Sir2 maintains the copy number of budding yeast ribosomal RNA gene [ribosomal DNA (rDNA)] by suppressing end resection of DNA double-strand breaks (DSBs) formed upon DNA replication fork arrest in the rDNA and their subsequent homologous recombination (HR)-mediated rDNA copy number changes during DSB repair. Sir2 represses transcription from the regulatory promoter E-pro located near the fork arresting site. When Sir2 is absent, this transcription is stimulated but terminated by arrested replication forks. This transcription-replication collision induces DSB formation, DSB end resection and the Mre11-Rad50-Xrs2 complex-dependent DSB repair that is prone to chromosomal rDNA copy number changes and the production of extrachromosomal rDNA circles. Therefore, repression of transcription near arrested replication forks is critical for the maintenance of rDNA stability by directing DSB repair into the HR-independent, rearrangement-free pathway.
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Affiliation(s)
- Mariko Sasaki
- Laboratory of Gene Quantity Biology, Center for Frontier Research, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka411-8540, Japan
- The Graduate University for Advanced Studies, SOKENDAI, 1111 Yata, Mishima, Shizuoka411-8540, Japan
- Laboratory of Genome Regeneration, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-0032, Japan
| | - Takehiko Kobayashi
- Laboratory of Genome Regeneration, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-0032, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-0032, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-0032, Japan
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2
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Xu Y, Morrow CA, Laksir Y, Holt OM, Taylor K, Tsiappourdhi C, Collins P, Jia S, Andreadis C, Whitby MC. DNA nicks in both leading and lagging strand templates can trigger break-induced replication. Mol Cell 2025; 85:91-106.e5. [PMID: 39561776 PMCID: PMC12095120 DOI: 10.1016/j.molcel.2024.10.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 09/09/2024] [Accepted: 10/22/2024] [Indexed: 11/21/2024]
Abstract
Encounters between replication forks and unrepaired DNA single-strand breaks (SSBs) can generate both single-ended and double-ended double-strand breaks (seDSBs and deDSBs). seDSBs can be repaired by break-induced replication (BIR), which is a highly mutagenic pathway that is thought to be responsible for many of the mutations and genome rearrangements that drive cancer development. However, the frequency of BIR's deployment and its ability to be triggered by both leading and lagging template strand SSBs were unclear. Using site- and strand-specific SSBs generated by nicking enzymes, including CRISPR-Cas9 nickase (Cas9n), we demonstrate that leading and lagging template strand SSBs in fission yeast are typically converted into deDSBs that are repaired by homologous recombination. However, both types of SSBs can also trigger BIR, and the frequency of these events increases when fork convergence is delayed and the non-homologous end joining protein Ku70 is deleted.
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Affiliation(s)
- Yuanlin Xu
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Carl A Morrow
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Yassine Laksir
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Orla M Holt
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Kezia Taylor
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Costas Tsiappourdhi
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Patrick Collins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Su Jia
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Christos Andreadis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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3
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Elango R, Nilavar NM, Li AG, Nguyen D, Rass E, Duffey EE, Jiang Y, Abakir A, Willis NA, Houseley J, Scully R. Two-ended recombination at a Flp-nickase-broken replication fork. Mol Cell 2025; 85:78-90.e3. [PMID: 39631396 PMCID: PMC11733529 DOI: 10.1016/j.molcel.2024.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 09/23/2024] [Accepted: 11/07/2024] [Indexed: 12/07/2024]
Abstract
Replication fork collision with a DNA nick can generate a one-ended break, fostering genomic instability. The opposing fork's collision with the nick could form a second DNA end, enabling conservative repair by homologous recombination (HR). To study mechanisms of nickase-induced HR, we developed the Flp recombinase "step arrest" nickase in mammalian cells. A Flp-nick induces two-ended, BRCA2/RAD51-dependent short tract gene conversion (STGC), BRCA2/RAD51-independent long tract gene conversion, and discoordinated two-ended invasions. HR pathways induced by a replication-independent break and the Flp-nickase differ in their dependence on BRCA1, MRE11, and CtIP. To determine the origin of the second DNA end during Flp-nickase-induced STGC, we blocked the opposing fork using a Tus/Ter replication fork barrier (RFB). Flp-nickase-induced STGC remained robust and two ended. Thus, a single replication fork's collision with a Flp-nick triggers two-ended HR, possibly reflecting replicative bypass of lagging strand nicks. This response may limit genomic instability during replication of nicked DNA.
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Affiliation(s)
- Rajula Elango
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Namrata M Nilavar
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Andrew G Li
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Daniel Nguyen
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Emilie Rass
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Erin E Duffey
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yuning Jiang
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Abdulkadir Abakir
- The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Nicholas A Willis
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Jonathan Houseley
- The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
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4
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Kimble MT, Sane A, Reid RJD, Johnson MJ, Rothstein R, Symington LS. Repair of replication-dependent double-strand breaks differs between the leading and lagging strands. Mol Cell 2025; 85:61-77.e6. [PMID: 39631395 PMCID: PMC11698654 DOI: 10.1016/j.molcel.2024.10.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 09/23/2024] [Accepted: 10/24/2024] [Indexed: 12/07/2024]
Abstract
Single-strand breaks (SSBs) are one of the most commonly occurring endogenous lesions with the potential to give rise to cytotoxic double-strand breaks (DSBs) during DNA replication. To investigate how replication-dependent DSBs are repaired, we employed Cas9 nickase (nCas9) to generate site- and strand-specific nicks in the budding yeast genome. We found that nCas9-induced nicks are converted to mostly double-ended DSBs during S phase. Repair of replication-associated DSBs requires homologous recombination (HR) and is independent of classical non-homologous end joining. Consistent with a strong bias to repair these lesions using a sister-chromatid template, we observed minimal induction of inter-chromosomal HR by nCas9. In a genome-wide screen to identify factors necessary for the repair of replication-dependent DSBs, we recovered components of the replication-coupled nucleosome assembly (RCNA) pathway. Our findings suggest that the RCNA pathway is especially important to repair DSBs arising from nicks in the leading-strand template through acetylation of histone H3K56.
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Affiliation(s)
- Michael T Kimble
- Program in Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Aakanksha Sane
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Robert J D Reid
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Matthew J Johnson
- Program in Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Rodney Rothstein
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA.
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5
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Di Nardo M, Musio A. Cohesin - bridging the gap among gene transcription, genome stability, and human diseases. FEBS Lett 2025; 599:190-208. [PMID: 38852996 DOI: 10.1002/1873-3468.14949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/15/2024] [Accepted: 05/08/2024] [Indexed: 06/11/2024]
Abstract
The intricate landscape of cellular processes governing gene transcription, chromatin organization, and genome stability is a fascinating field of study. A key player in maintaining this delicate equilibrium is the cohesin complex, a molecular machine with multifaceted roles. This review presents an in-depth exploration of these intricate connections and their significant impact on various human diseases.
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Affiliation(s)
- Maddalena Di Nardo
- Institute for Biomedical Technologies (ITB), National Research Council (CNR), Pisa, Italy
| | - Antonio Musio
- Institute for Biomedical Technologies (ITB), National Research Council (CNR), Pisa, Italy
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6
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Li L, Scott WS, Khristich AN, Armenia JF, Mirkin SM. Recurrent DNA nicks drive massive expansions of (GAA) n repeats. Proc Natl Acad Sci U S A 2024; 121:e2413298121. [PMID: 39585990 PMCID: PMC11626148 DOI: 10.1073/pnas.2413298121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 10/21/2024] [Indexed: 11/27/2024] Open
Abstract
Over 50 hereditary degenerative disorders are caused by expansions of short tandem DNA repeats (STRs). (GAA)n repeat expansions are responsible for Friedreich's ataxia as well as late-onset cerebellar ataxias (LOCAs). Thus, the mechanisms of (GAA)n repeat expansions attract broad scientific attention. To investigate the role of DNA nicks in this process, we utilized a CRISPR-Cas9 nickase system to introduce targeted nicks adjacent to the (GAA)n repeat tract. We found that DNA nicks 5' of the (GAA)100 run led to a dramatic increase in both the rate and scale of its expansion in dividing cells. Strikingly, they also promoted large-scale expansions of carrier- and large normal-size (GAA)n repeats, recreating, in a model system, the expansion events that occur in human pedigrees. DNA nicks 3' of the (GAA)100 repeat led to a smaller but significant increase in the expansion rate as well. Our genetic analysis implies that in dividing cells, conversion of nicks into double-strand breaks (DSBs) during DNA replication followed by DSB or fork repair leads to repeat expansions. Finally, we showed that 5' GAA-strand nicks increase expansion frequency in nondividing yeast cells, albeit to a lesser extent than in dividing cells.
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Affiliation(s)
- Liangzi Li
- Department of Biology, Tufts University, Medford, MA02155
| | - W. Shem Scott
- Department of Biology, Tufts University, Medford, MA02155
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7
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Scully R, Walter JC, Nussenzweig A. One-ended and two-ended breaks at nickase-broken replication forks. DNA Repair (Amst) 2024; 144:103783. [PMID: 39504607 DOI: 10.1016/j.dnarep.2024.103783] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Revised: 09/30/2024] [Accepted: 11/02/2024] [Indexed: 11/08/2024]
Abstract
Replisome collision with a nicked parental DNA template can lead to the formation of a replication-associated double strand break (DSB). How this break is repaired has implications for cancer initiation, cancer therapy and therapeutic gene editing. Recent work shows that collision of a replisome with a nicked DNA template can give rise to either a single-ended (se) or a double-ended (de)DSB, with potentially divergent effects on repair pathway choice and genomic instability. Emerging evidence suggests that the biochemical environment of the broken mammalian replication fork may be specialized in such a way as to skew repair in favor of homologous recombination at the expense of non-homologous end joining.
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Affiliation(s)
- Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
| | - Johannes C Walter
- Department of Biological Chemistry & Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
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8
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Triplett MK, Johnson MJ, Symington LS. Induction of homologous recombination by site-specific replication stress. DNA Repair (Amst) 2024; 142:103753. [PMID: 39190984 PMCID: PMC11425181 DOI: 10.1016/j.dnarep.2024.103753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 08/07/2024] [Accepted: 08/12/2024] [Indexed: 08/29/2024]
Abstract
DNA replication stress is one of the primary causes of genome instability. In response to replication stress, cells can employ replication restart mechanisms that rely on homologous recombination to resume replication fork progression and preserve genome integrity. In this review, we provide an overview of various methods that have been developed to induce site-specific replication fork stalling or collapse in eukaryotic cells. In particular, we highlight recent studies of mechanisms of replication-associated recombination resulting from site-specific protein-DNA barriers and single-strand breaks, and we discuss the contributions of these findings to our understanding of the consequences of these forms of stress on genome stability.
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Affiliation(s)
- Marina K Triplett
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, New York, NY 10032, United States; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, United States
| | - Matthew J Johnson
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, United States; Program in Biological Sciences, Columbia University, New York, NY 10027, United States
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, United States; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, United States.
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9
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Schreuder A, Wendel TJ, Dorresteijn CGV, Noordermeer SM. (Single-stranded DNA) gaps in understanding BRCAness. Trends Genet 2024; 40:757-771. [PMID: 38789375 DOI: 10.1016/j.tig.2024.04.013] [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: 02/02/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024]
Abstract
The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, and single-stranded (ss)DNA gap suppression - and their relative importance is under debate. In this review, we examine the origin and resolution of ssDNA gaps and discuss the recent advances in understanding the role of BRCA1/2 in gap suppression. There are ample data showing that gap accumulation in BRCA1/2-deficient cells is linked to genomic instability and chemosensitivity. However, it remains unclear whether there is a causative role and the function of BRCA1/2 in gap suppression cannot unambiguously be dissected from their other functions. We therefore conclude that the three functions of BRCA1 and 2 are closely intertwined and not mutually exclusive.
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Affiliation(s)
- Anne Schreuder
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Tiemen J Wendel
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Carlo G V Dorresteijn
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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10
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Kimble MT, Sane A, Reid RJ, Johnson MJ, Rothstein R, Symington LS. Strand asymmetry in the repair of replication dependent double-strand breaks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.598707. [PMID: 38948862 PMCID: PMC11212877 DOI: 10.1101/2024.06.17.598707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Single-strand breaks (SSBs) are one of the most common endogenous lesions and have the potential to give rise to cytotoxic double-strand breaks (DSBs) during DNA replication. To investigate the mechanism of replication fork collapse at SSBs and subsequent repair, we employed Cas9 nickase (nCas9) to generate site and strand-specific nicks in the budding yeast genome. We show that nCas9-induced nicks are converted to mostly double-ended DSBs during S-phase. We find that repair of replication-dependent DSBs requires homologous recombination (HR) and is independent of canonical non-homologous end joining. Consistent with a strong bias to repair these lesions using a sister chromatid template, we observe minimal induction of inter-chromosomal HR by nCas9. Using nCas9 and a gRNA to nick either the leading or lagging strand template, we carried out a genome-wide screen to identify factors necessary for the repair of replication-dependent DSBs. All the core HR genes were recovered in the screen with both gRNAs, but we recovered components of the replication-coupled nucleosome assembly (RCNA) pathway with only the gRNA targeting the leading strand template. By use of additional gRNAs, we find that the RCNA pathway is especially important to repair a leading strand fork collapse.
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11
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Elango R, Nilavar N, Li AG, Duffey EE, Jiang Y, Nguyen D, Abakir A, Willis NA, Houseley J, Scully R. Two-ended recombination at a Flp-nickase-broken replication fork. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588130. [PMID: 38645103 PMCID: PMC11030319 DOI: 10.1101/2024.04.10.588130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Collision of a replication fork with a DNA nick is thought to generate a one-ended break, fostering genomic instability. Collision of the opposing converging fork with the nick could, in principle, form a second DNA end, enabling conservative repair by homologous recombination (HR). To study mechanisms of nickase-induced HR, we developed the Flp recombinase "step arrest" nickase in mammalian cells. Flp-nickase-induced HR entails two-ended, BRCA2/RAD51-dependent short tract gene conversion (STGC), BRCA2/RAD51-independent long tract gene conversion, and discoordinated two-ended invasions. HR induced by a replication-independent break and by the Flp-nickase differ in their dependence on BRCA1 . To determine the origin of the second DNA end during Flp-nickase-induced STGC, we blocked the opposing fork using a site-specific Tus/ Ter replication fork barrier. Flp-nickase-induced STGC remained robust and two-ended. Thus, collision of a single replication fork with a Flp-nick can trigger two-ended HR, possibly reflecting replicative bypass of lagging strand nicks. This response may limit genomic instability during replication of a nicked DNA template.
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12
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Andronikou C, Burdova K, Dibitetto D, Lieftink C, Malzer E, Kuiken HJ, Gogola E, Ray Chaudhuri A, Beijersbergen RL, Hanzlikova H, Jonkers J, Rottenberg S. PARG-deficient tumor cells have an increased dependence on EXO1/FEN1-mediated DNA repair. EMBO J 2024; 43:1015-1042. [PMID: 38360994 PMCID: PMC10943112 DOI: 10.1038/s44318-024-00043-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
Targeting poly(ADP-ribose) glycohydrolase (PARG) is currently explored as a therapeutic approach to treat various cancer types, but we have a poor understanding of the specific genetic vulnerabilities that would make cancer cells susceptible to such a tailored therapy. Moreover, the identification of such vulnerabilities is of interest for targeting BRCA2;p53-deficient tumors that have acquired resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) through loss of PARG expression. Here, by performing whole-genome CRISPR/Cas9 drop-out screens, we identify various genes involved in DNA repair to be essential for the survival of PARG;BRCA2;p53-deficient cells. In particular, our findings reveal EXO1 and FEN1 as major synthetic lethal interactors of PARG loss. We provide evidence for compromised replication fork progression, DNA single-strand break repair, and Okazaki fragment processing in PARG;BRCA2;p53-deficient cells, alterations that exacerbate the effects of EXO1/FEN1 inhibition and become lethal in this context. Since this sensitivity is dependent on BRCA2 defects, we propose to target EXO1/FEN1 in PARPi-resistant tumors that have lost PARG activity. Moreover, EXO1/FEN1 targeting may be a useful strategy for enhancing the effect of PARG inhibitors in homologous recombination-deficient tumors.
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Affiliation(s)
- Christina Andronikou
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland
| | - Kamila Burdova
- Laboratory of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Diego Dibitetto
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland
| | - Cor Lieftink
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Elke Malzer
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Hendrik J Kuiken
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Ewa Gogola
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Arnab Ray Chaudhuri
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015GD, Rotterdam, The Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
- The Netherlands Cancer Institute Robotics and Screening Center, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Hana Hanzlikova
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
- Laboratory of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Jos Jonkers
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands.
- Oncode Institute, Amsterdam, The Netherlands.
| | - Sven Rottenberg
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland.
- Division of Molecular Pathology, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands.
- Cancer Therapy Resistance Cluster and Bern Center for Precision Medicine, Department for Biomedical Research, University of Bern, 3088, Bern, Switzerland.
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13
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van de Kooij B, Schreuder A, Pavani R, Garzero V, Uruci S, Wendel TJ, van Hoeck A, San Martin Alonso M, Everts M, Koerse D, Callen E, Boom J, Mei H, Cuppen E, Luijsterburg MS, van Vugt MATM, Nussenzweig A, van Attikum H, Noordermeer SM. EXO1 protects BRCA1-deficient cells against toxic DNA lesions. Mol Cell 2024; 84:659-674.e7. [PMID: 38266640 DOI: 10.1016/j.molcel.2023.12.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/14/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Inactivating mutations in the BRCA1 and BRCA2 genes impair DNA double-strand break (DSB) repair by homologous recombination (HR), leading to chromosomal instability and cancer. Importantly, BRCA1/2 deficiency also causes therapeutically targetable vulnerabilities. Here, we identify the dependency on the end resection factor EXO1 as a key vulnerability of BRCA1-deficient cells. EXO1 deficiency generates poly(ADP-ribose)-decorated DNA lesions during S phase that associate with unresolved DSBs and genomic instability in BRCA1-deficient but not in wild-type or BRCA2-deficient cells. Our data indicate that BRCA1/EXO1 double-deficient cells accumulate DSBs due to impaired repair by single-strand annealing (SSA) on top of their HR defect. In contrast, BRCA2-deficient cells retain SSA activity in the absence of EXO1 and hence tolerate EXO1 loss. Consistent with a dependency on EXO1-mediated SSA, we find that BRCA1-mutated tumors show elevated EXO1 expression and increased SSA-associated genomic scars compared with BRCA1-proficient tumors. Overall, our findings uncover EXO1 as a promising therapeutic target for BRCA1-deficient tumors.
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Affiliation(s)
- Bert van de Kooij
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Anne Schreuder
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Raphael Pavani
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Veronica Garzero
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Sidrit Uruci
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Tiemen J Wendel
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Arne van Hoeck
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands
| | - Marta San Martin Alonso
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Marieke Everts
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Dana Koerse
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jasper Boom
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Edwin Cuppen
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands; Hartwig Medical Foundation, Amsterdam 1098 XH, the Netherlands
| | - Martijn S Luijsterburg
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Marcel A T M van Vugt
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands.
| | - Sylvie M Noordermeer
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands.
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14
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Bailey SM, Cross EM, Kinner-Bibeau L, Sebesta HC, Bedford JS, Tompkins CJ. Monitoring Genomic Structural Rearrangements Resulting from Gene Editing. J Pers Med 2024; 14:110. [PMID: 38276232 PMCID: PMC10817574 DOI: 10.3390/jpm14010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/04/2024] [Accepted: 01/13/2024] [Indexed: 01/27/2024] Open
Abstract
The cytogenomics-based methodology of directional genomic hybridization (dGH) enables the detection and quantification of a more comprehensive spectrum of genomic structural variants than any other approach currently available, and importantly, does so on a single-cell basis. Thus, dGH is well-suited for testing and/or validating new advancements in CRISPR-Cas9 gene editing systems. In addition to aberrations detected by traditional cytogenetic approaches, the strand specificity of dGH facilitates detection of otherwise cryptic intra-chromosomal rearrangements, specifically small inversions. As such, dGH represents a powerful, high-resolution approach for the quantitative monitoring of potentially detrimental genomic structural rearrangements resulting from exposure to agents that induce DNA double-strand breaks (DSBs), including restriction endonucleases and ionizing radiations. For intentional genome editing strategies, it is critical that any undesired effects of DSBs induced either by the editing system itself or by mis-repair with other endogenous DSBs are recognized and minimized. In this paper, we discuss the application of dGH for assessing gene editing-associated structural variants and the potential heterogeneity of such rearrangements among cells within an edited population, highlighting its relevance to personalized medicine strategies.
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Affiliation(s)
- Susan M. Bailey
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA;
- KromaTiD, Inc., Longmont, CO 80501, USA; (E.M.C.); (L.K.-B.); (H.C.S.)
| | - Erin M. Cross
- KromaTiD, Inc., Longmont, CO 80501, USA; (E.M.C.); (L.K.-B.); (H.C.S.)
| | | | - Henry C. Sebesta
- KromaTiD, Inc., Longmont, CO 80501, USA; (E.M.C.); (L.K.-B.); (H.C.S.)
| | - Joel S. Bedford
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA;
- KromaTiD, Inc., Longmont, CO 80501, USA; (E.M.C.); (L.K.-B.); (H.C.S.)
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15
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Gómez-González B, Aguilera A. Break-induced RNA-DNA hybrids (BIRDHs) in homologous recombination: friend or foe? EMBO Rep 2023; 24:e57801. [PMID: 37818834 DOI: 10.15252/embr.202357801] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/29/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023] Open
Abstract
Double-strand breaks (DSBs) are the most harmful DNA lesions, with a strong impact on cell proliferation and genome integrity. Depending on cell cycle stage, DSBs are preferentially repaired by non-homologous end joining or homologous recombination (HR). In recent years, numerous reports have revealed that DSBs enhance DNA-RNA hybrid formation around the break site. We call these hybrids "break-induced RNA-DNA hybrids" (BIRDHs) to differentiate them from sporadic R-loops consisting of DNA-RNA hybrids and a displaced single-strand DNA occurring co-transcriptionally in intact DNA. Here, we review and discuss the most relevant data about BIRDHs, with a focus on two main questions raised: (i) whether BIRDHs form by de novo transcription after a DSB or by a pre-existing nascent RNA in DNA regions undergoing transcription and (ii) whether they have a positive role in HR or are just obstacles to HR accidentally generated as an intrinsic risk of transcription. We aim to provide a comprehensive view of the exciting and yet unresolved questions about the source and impact of BIRDHs in the cell.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
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16
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Serrano‐Benitez A, Wells SE, Drummond‐Clarke L, Russo LC, Thomas JC, Leal GA, Farrow M, Edgerton JM, Balasubramanian S, Yang M, Frezza C, Gautam A, Brazina J, Burdova K, Hoch NC, Jackson SP, Caldecott KW. Unrepaired base excision repair intermediates in template DNA strands trigger replication fork collapse and PARP inhibitor sensitivity. EMBO J 2023; 42:e113190. [PMID: 37492888 PMCID: PMC10505916 DOI: 10.15252/embj.2022113190] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 05/17/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
DNA single-strand breaks (SSBs) disrupt DNA replication and induce chromosome breakage. However, whether SSBs induce chromosome breakage when present behind replication forks or ahead of replication forks is unclear. To address this question, we exploited an exquisite sensitivity of SSB repair-defective human cells lacking PARP activity or XRCC1 to the thymidine analogue 5-chloro-2'-deoxyuridine (CldU). We show that incubation with CldU in these cells results in chromosome breakage, sister chromatid exchange, and cytotoxicity by a mechanism that depends on the S phase activity of uracil DNA glycosylase (UNG). Importantly, we show that CldU incorporation in one cell cycle is cytotoxic only during the following cell cycle, when it is present in template DNA. In agreement with this, while UNG induces SSBs both in nascent strands behind replication forks and in template strands ahead of replication forks, only the latter trigger fork collapse and chromosome breakage. Finally, we show that BRCA-defective cells are hypersensitive to CldU, either alone and/or in combination with PARP inhibitor, suggesting that CldU may have clinical utility.
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Affiliation(s)
- Almudena Serrano‐Benitez
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
- The Wellcome and Cancer Research UK Gurdon Institute and Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Sophie E Wells
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
| | - Lylah Drummond‐Clarke
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
| | - Lilian C Russo
- Departament of Biochemistry, Chemistry InstituteUniversity of São PauloSão PauloBrazil
| | - John Christopher Thomas
- The Wellcome and Cancer Research UK Gurdon Institute and Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Giovanna A Leal
- Departament of Biochemistry, Chemistry InstituteUniversity of São PauloSão PauloBrazil
| | - Mark Farrow
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | | | - Shankar Balasubramanian
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Ming Yang
- CECAD Research Center, Faculty of MedicineUniversity Hospital CologneCologneGermany
| | - Christian Frezza
- CECAD Research Center, Faculty of MedicineUniversity Hospital CologneCologneGermany
| | - Amit Gautam
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
| | - Jan Brazina
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
| | - Kamila Burdova
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
| | - Nicolas C Hoch
- Departament of Biochemistry, Chemistry InstituteUniversity of São PauloSão PauloBrazil
| | - Stephen P Jackson
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
- The Wellcome and Cancer Research UK Gurdon Institute and Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Keith W Caldecott
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexFalmerUK
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17
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van de Kooij B, Schreuder A, Pavani RS, Garzero V, Van Hoeck A, San Martin Alonso M, Koerse D, Wendel TJ, Callen E, Boom J, Mei H, Cuppen E, Nussenzweig A, van Attikum H, Noordermeer SM. EXO1-mediated DNA repair by single-strand annealing is essential for BRCA1-deficient cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.24.529205. [PMID: 37720033 PMCID: PMC10503826 DOI: 10.1101/2023.02.24.529205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Deficiency for the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR) leads to chromosomal instability and diseases such as cancer. Yet, defective HR also results in vulnerabilities that can be exploited for targeted therapy. Here, we identify such a vulnerability and show that BRCA1-deficient cells are dependent on the long-range end-resection factor EXO1 for survival. EXO1 loss results in DNA replication-induced lesions decorated by poly(ADP-ribose)-chains. In cells that lack both BRCA1 and EXO1, this is accompanied by unresolved DSBs due to impaired single-strand annealing (SSA), a DSB repair process that requires the activity of both proteins. In contrast, BRCA2-deficient cells have increased SSA, also in the absence of EXO1, and hence are not dependent on EXO1 for survival. In agreement with our mechanistic data, BRCA1-mutated tumours have elevated EXO1 expression and contain more genomic signatures of SSA compared to BRCA1-proficient tumours. Collectively, our data indicate that EXO1 is a promising novel target for treatment of BRCA1-deficient tumours.
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18
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Kuchi Bhotla H, Balasubramanian B, Rengasamy KRR, Arumugam VA, Alagamuthu KK, Chithravel V, Chaudhary A, Alanazi AM, Pappuswamy M, Meyyazhagan A. Genotoxic repercussion of high-intensity radiation (x-rays) on hospital radiographers. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:123-131. [PMID: 36541415 DOI: 10.1002/em.22523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 05/24/2023]
Abstract
Recent technological advances in the medical field have increased the plausibility of exposing humans to high-intensity wavelength radiations like x-rays and gamma rays while diagnosing or treating specific medical maladies. These radiations induce nucleotide changes and chromosomal alterations in the exposed population, intentionally or accidentally. A radiological investigation is regularly used in identifying the disease, especially by the technicians working in intensive care units. The current study observes the genetic damages like chromosomal abnormalities (CA) in clinicians who are occupationally exposed to high-intensity radiations (x-rays) at their workplaces using universal cytogenetic tools like micronucleus assay (MN), sister chromatid exchange and comet assay. The study was conducted between 100 exposed practitioners from the abdominal scanning, chest scanning, cranial and orthopedic or bone scanning department and age-matched healthy controls. We observed a slightly higher rate of MN and CA (p < .05) in orthopedic and chest department practitioners than in other departments concerning increasing age and duration of exposure at work. Our results emphasize taking extra precautionary measures in clinical and hospital radiation laboratories to protect the practitioners.
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Affiliation(s)
| | | | - Kannan R R Rengasamy
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
- Laboratory of Natural Products and Medicinal Chemistry (LNPMC), Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India
| | - Vijaya Anand Arumugam
- Medical Genetics and Epigenetics Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - Karthick Kumar Alagamuthu
- Department of Biotechnology, Selvamm Arts and Science College (Autonomous), Namakkal, Tamil Nadu, India
| | | | - Aditi Chaudhary
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, India
| | - Amer M Alanazi
- Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | | | - Arun Meyyazhagan
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, India
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19
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Jiang Y. Contribution of Microhomology to Genome Instability: Connection between DNA Repair and Replication Stress. Int J Mol Sci 2022; 23:12937. [PMID: 36361724 PMCID: PMC9657218 DOI: 10.3390/ijms232112937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/23/2022] [Accepted: 10/23/2022] [Indexed: 11/23/2023] Open
Abstract
Microhomology-mediated end joining (MMEJ) is a highly mutagenic pathway to repair double-strand breaks (DSBs). MMEJ was thought to be a backup pathway of homologous recombination (HR) and canonical nonhomologous end joining (C-NHEJ). However, it attracts more attention in cancer research due to its special function of microhomology in many different aspects of cancer. In particular, it is initiated with DNA end resection and upregulated in homologous recombination-deficient cancers. In this review, I summarize the following: (1) the recent findings and contributions of MMEJ to genome instability, including phenotypes relevant to MMEJ; (2) the interaction between MMEJ and other DNA repair pathways; (3) the proposed mechanistic model of MMEJ in DNA DSB repair and a new connection with microhomology-mediated break-induced replication (MMBIR); and (4) the potential clinical application by targeting MMEJ based on synthetic lethality for cancer therapy.
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Affiliation(s)
- Yuning Jiang
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA 22903, USA
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20
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Paranjape AM, Desai SS, Nishana M, Roy U, Nilavar NM, Mondal A, Kumari R, Radha G, Katapadi VK, Choudhary B, Raghavan SC. Nonamer dependent RAG cleavage at CpGs can explain mechanism of chromosomal translocations associated to lymphoid cancers. PLoS Genet 2022; 18:e1010421. [PMID: 36228010 PMCID: PMC9595545 DOI: 10.1371/journal.pgen.1010421] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/25/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Chromosomal translocations are considered as one of the major causes of lymphoid cancers. RAG complex, which is responsible for V(D)J recombination, can also cleave non-B DNA structures and cryptic RSSs in the genome leading to chromosomal translocations. The mechanism and factors regulating the illegitimate function of RAGs resulting in oncogenesis are largely unknown. Upon in silico analysis of 3760 chromosomal translocations from lymphoid cancer patients, we find that 93% of the translocation breakpoints possess adjacent cryptic nonamers (RAG binding sequences), of which 77% had CpGs in proximity. As a proof of principle, we show that RAGs can efficiently bind to cryptic nonamers present at multiple fragile regions and cleave at adjacent mismatches generated to mimic the deamination of CpGs. ChIP studies reveal that RAGs can indeed recognize these fragile sites on a chromatin context inside the cell. Finally, we show that AID, the cytidine deaminase, plays a significant role during the generation of mismatches at CpGs and reconstitute the process of RAG-dependent generation of DNA breaks both in vitro and inside the cells. Thus, we propose a novel mechanism for generation of chromosomal translocation, where RAGs bind to the cryptic nonamer sequences and direct cleavage at adjacent mismatch generated due to deamination of meCpGs or cytosines.
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Affiliation(s)
- Amita M. Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sagar S. Desai
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Mayilaadumveettil Nishana
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Namrata M. Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Amrita Mondal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Gudapureddy Radha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- * E-mail: (BC); (SCR)
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- * E-mail: (BC); (SCR)
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21
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Cañas JC, García-Rubio ML, García A, Antequera F, Gómez-González B, Aguilera A. A role for the Saccharomyces cerevisiae Rtt109 histone acetyltransferase in R-loop homeostasis and associated genome instability. Genetics 2022; 222:6648348. [PMID: 35866610 PMCID: PMC9434296 DOI: 10.1093/genetics/iyac108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 07/08/2022] [Indexed: 12/02/2022] Open
Abstract
The stability of the genome is occasionally challenged by the formation of DNA–RNA hybrids and R-loops, which can be influenced by the chromatin context. This is mainly due to the fact that DNA–RNA hybrids hamper the progression of replication forks, leading to fork stalling and, ultimately, DNA breaks. Through a specific screening of chromatin modifiers performed in the yeast Saccharomyces cerevisiae, we have found that the Rtt109 histone acetyltransferase is involved in several steps of R-loop-metabolism and their associated genetic instability. On the one hand, Rtt109 prevents DNA–RNA hybridization by the acetylation of histone H3 lysines 14 and 23 and, on the other hand, it is involved in the repair of replication-born DNA breaks, such as those that can be caused by R-loops, by acetylating lysines 14 and 56. In addition, Rtt109 loss renders cells highly sensitive to replication stress in combination with R-loop-accumulating THO-complex mutants. Our data evidence that the chromatin context simultaneously influences the occurrence of DNA–RNA hybrid-associated DNA damage and its repair, adding complexity to the source of R-loop-associated genetic instability.
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Affiliation(s)
- Juan Carlos Cañas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, 41092 Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - María Luisa García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, 41092 Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Alicia García
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-Universidad de Salamanca, 37007, Salamanca, Spain
| | - Francisco Antequera
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-Universidad de Salamanca, 37007, Salamanca, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, 41092 Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, 41092 Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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22
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Jha JS, Yin J, Haldar T, Wang Y, Gates KS. Reconsidering the Chemical Nature of Strand Breaks Derived from Abasic Sites in Cellular DNA: Evidence for 3'-Glutathionylation. J Am Chem Soc 2022; 144:10471-10482. [PMID: 35612610 DOI: 10.1021/jacs.2c02703] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The hydrolytic loss of coding bases from cellular DNA is a common and unavoidable reaction. The resulting abasic sites can undergo β-elimination of the 3'-phosphoryl group to generate a strand break with an electrophilic α,β-unsaturated aldehyde residue on the 3'-terminus. The work reported here provides evidence that the thiol residue of the cellular tripeptide glutathione rapidly adds to the alkenal group on the 3'-terminus of an AP-derived strand break. The resulting glutathionylated adduct is the only major cleavage product observed when β-elimination occurs at an AP site in the presence of glutathione. Formation of the glutathionylated cleavage product is reversible, but in the presence of physiological concentrations of glutathione, the adduct persists for days. Biochemical experiments provided evidence that the 3'-phosphodiesterase activity of the enzyme apurinic/apyrimidinic endonuclease (APE1) can remove the glutathionylated sugar remnant from an AP-derived strand break to generate the 3'OH residue required for repair via base excision or single-strand break repair pathways. The results suggest that a previously unrecognized 3'glutathionylated sugar remnant─and not the canonical α,β-unsaturated aldehyde end group─may be the true strand cleavage product arising from β-elimination at an abasic site in cellular DNA. This work introduces the 3'glutathionylated cleavage product as the major blocking group that must be trimmed to enable repair of abasic site-derived strand breaks by the base excision repair or single-strand break repair pathways.
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23
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Mechanisms of DNA Mobilization and Sequestration. Genes (Basel) 2022; 13:genes13020352. [PMID: 35205396 PMCID: PMC8872102 DOI: 10.3390/genes13020352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 12/04/2022] Open
Abstract
The entire genome becomes mobilized following DNA damage. Understanding the mechanisms that act at the genome level requires that we embrace experimental and computational strategies to capture the behavior of the long-chain DNA polymer, which is the building block for the chromosome. Long-chain polymers exhibit constrained, sub-diffusive motion in the nucleus. Cross-linking proteins, including cohesin and condensin, have a disproportionate effect on genome organization in their ability to stabilize transient interactions. Cross-linking proteins can segregate the genome into sub-domains through polymer–polymer phase separation (PPPS) and can drive the formation of gene clusters through small changes in their binding kinetics. Principles from polymer physics provide a means to unravel the mysteries hidden in the chains of life.
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24
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Ortega P, Gómez-González B, Aguilera A. Heterogeneity of DNA damage incidence and repair in different chromatin contexts. DNA Repair (Amst) 2021; 107:103210. [PMID: 34416542 DOI: 10.1016/j.dnarep.2021.103210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 11/18/2022]
Abstract
It has been long known that some regions of the genome are more susceptible to damage and mutagenicity than others. Recent advances have determined a critical role of chromatin both in the incidence of damage and in its repair. Thus, chromatin arises as a guardian of the stability of the genome, which is altered in cancer cells. In this review, we focus into the mechanisms by which chromatin influences the occurrence and repair of the most cytotoxic DNA lesions, double-strand breaks, in particular at actively transcribed chromatin or related to DNA replication.
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Affiliation(s)
- Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain.
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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25
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Gómez-González B, Ortega P, Aguilera A. Analysis of repair of replication-born double-strand breaks by sister chromatid recombination in yeast. Methods Enzymol 2021; 661:121-138. [PMID: 34776209 DOI: 10.1016/bs.mie.2021.08.010] [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] [Indexed: 01/04/2023]
Abstract
The repair of DNA double-strand breaks is crucial for cell viability and the maintenance of genome integrity. When present, the intact sister chromatid is used as the preferred repair template to restore the genetic information by homologous recombination. Although the study of the factors involved in sister chromatid recombination is hampered by the fact that both sister chromatids are indistinguishable, genetic and molecular systems based on DNA repeats have been developed to overcome this problem. In particular, the use of site-specific nucleases capable of inducing DNA nicks that replication converts into double-strand breaks has enabled the specific study of the repair of such replication-born double strand breaks by sister chromatid recombination. In this chapter, we describe detailed protocols for determining the efficiency and kinetics of this recombination reaction as well as for the genetic quantification of recombination products.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain.
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26
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Rashid I, Hammel M, Sverzhinsky A, Tsai MS, Pascal JM, Tainer JA, Tomkinson AE. Direct interaction of DNA repair protein tyrosyl DNA phosphodiesterase 1 and the DNA ligase III catalytic domain is regulated by phosphorylation of its flexible N-terminus. J Biol Chem 2021; 297:100921. [PMID: 34181949 PMCID: PMC8318918 DOI: 10.1016/j.jbc.2021.100921] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
Tyrosyl DNA phosphodiesterase 1 (TDP1) and DNA Ligase IIIα (LigIIIα) are key enzymes in single-strand break (SSB) repair. TDP1 removes 3'-tyrosine residues remaining after degradation of DNA topoisomerase (TOP) 1 cleavage complexes trapped by either DNA lesions or TOP1 inhibitors. It is not known how TDP1 is linked to subsequent processing and LigIIIα-catalyzed joining of the SSB. Here we define a direct interaction between the TDP1 catalytic domain and the LigIII DNA-binding domain (DBD) regulated by conformational changes in the unstructured TDP1 N-terminal region induced by phosphorylation and/or alterations in amino acid sequence. Full-length and N-terminally truncated TDP1 are more effective at correcting SSB repair defects in TDP1 null cells compared with full-length TDP1 with amino acid substitutions of an N-terminal serine residue phosphorylated in response to DNA damage. TDP1 forms a stable complex with LigIII170-755, as well as full-length LigIIIα alone or in complex with the DNA repair scaffold protein XRCC1. Small-angle X-ray scattering and negative stain electron microscopy combined with mapping of the interacting regions identified a TDP1/LigIIIα compact dimer of heterodimers in which the two LigIII catalytic cores are positioned in the center, whereas the two TDP1 molecules are located at the edges of the core complex flanked by highly flexible regions that can interact with other repair proteins and SSBs. As TDP1and LigIIIα together repair adducts caused by TOP1 cancer chemotherapy inhibitors, the defined interaction architecture and regulation of this enzyme complex provide insights into a key repair pathway in nonmalignant and cancer cells.
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Affiliation(s)
- Ishtiaque Rashid
- Departments of Internal Medicine, Molecular Genetics and Microbiology and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, USA
| | - Michal Hammel
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Aleksandr Sverzhinsky
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Miaw-Sheue Tsai
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - John M Pascal
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
| | - Alan E Tomkinson
- Departments of Internal Medicine, Molecular Genetics and Microbiology and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, Albuquerque, New Mexico, USA.
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27
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Al-Zain AM, Symington LS. The dark side of homology-directed repair. DNA Repair (Amst) 2021; 106:103181. [PMID: 34311272 DOI: 10.1016/j.dnarep.2021.103181] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 10/20/2022]
Abstract
DNA double strand breaks (DSB) are cytotoxic lesions that can lead to genome rearrangements and genomic instability, which are hallmarks of cancer. The two main DSB repair pathways are non-homologous end joining and homologous recombination (HR). While HR is generally highly accurate, it has the potential for rearrangements that occur directly or through intermediates generated during the repair process. Whole genome sequencing of cancers has revealed numerous types of structural rearrangement signatures that are often indicative of repair mediated by sequence homology. However, it can be challenging to delineate repair mechanisms from sequence analysis of rearrangement end products from cancer genomes, or even model systems, because the same rearrangements can be generated by different pathways. Here, we review homology-directed repair pathways and their consequences. Exploring those pathways can lead to a greater understanding of rearrangements that occur in cancer cells.
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Affiliation(s)
- Amr M Al-Zain
- Program in Biological Sciences, Columbia University, New York, NY, 10027, United States; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, 10032, United States.
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28
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Sun R, Wen M, Wu L, Lan H, Yuan J, Wang S. The Fungi-specific histone Acetyltransferase Rtt109 mediates morphogenesis, Aflatoxin synthesis and pathogenicity in Aspergillus flavus by acetylating H3K9. IMA Fungus 2021; 12:9. [PMID: 33823938 PMCID: PMC8025522 DOI: 10.1186/s43008-021-00060-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 03/21/2021] [Indexed: 11/26/2022] Open
Abstract
Aspergillus flavus is a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process. Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase. In this study, we used Aspergillus flavus as an experimental model to construct the acetyltransferase gene rtt109 knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination. The growth of △rtt109 was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain. The sclerotium of △rtt109 grew smaller, and the amount of sclerotia generated by △rtt109 was significantly reduced. The number of conidiums of △rtt109 was significantly reduced, especially on the yeast extract sucrose (YES) solid medium. The amount of aflatoxins synthesized by △rtt109 in the PDB liquid medium was significantly decreased We also found that the △rtt109 strain was extremely sensitive to DNA damage stress. Through the maize seed infection experiment, we found that the growth of △rtt109 on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium. We further found that H3K9 was the acetylated target of Rtt109 in A. flavus. In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection of A. flavus. The results from this study of rtt109 showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control of A. flavus hazards.
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Affiliation(s)
- Ruilin Sun
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Meifang Wen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lianghuan Wu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huahui Lan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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29
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Kockler ZW, Osia B, Lee R, Musmaker K, Malkova A. Repair of DNA Breaks by Break-Induced Replication. Annu Rev Biochem 2021; 90:165-191. [PMID: 33792375 DOI: 10.1146/annurev-biochem-081420-095551] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Double-strand DNA breaks (DSBs) are the most lethal type of DNA damage, making DSB repair critical for cell survival. However, some DSB repair pathways are mutagenic and promote genome rearrangements, leading to genome destabilization. One such pathway is break-induced replication (BIR), which repairs primarily one-ended DSBs, similar to those formed by collapsed replication forks or telomere erosion. BIR is initiated by the invasion of a broken DNA end into a homologous template, synthesizes new DNA within the context of a migrating bubble, and is associated with conservative inheritance of new genetic material. This mode of synthesis is responsible for a high level of genetic instability associated with BIR. Eukaryotic BIR was initially investigated in yeast, but now it is also actively studied in mammalian systems. Additionally, a significant breakthrough has been made regarding the role of microhomology-mediated BIR in the formation of complex genomic rearrangements that underly various human pathologies.
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Affiliation(s)
- Z W Kockler
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - B Osia
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - R Lee
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - K Musmaker
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - A Malkova
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
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30
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Su XA, Ma D, Parsons JV, Replogle JM, Amatruda JF, Whittaker CA, Stegmaier K, Amon A. RAD21 is a driver of chromosome 8 gain in Ewing sarcoma to mitigate replication stress. Genes Dev 2021; 35:556-572. [PMID: 33766983 PMCID: PMC8015718 DOI: 10.1101/gad.345454.120] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 02/25/2021] [Indexed: 01/08/2023]
Abstract
In this study, Su et al. investigate why ∼50% of Ewing sarcomas, driven by the EWS-FLI1 fusion oncogene, harbor chromosome 8 gains. Using an evolution approach, they show that trisomy 8 mitigates EWS-FLI1-induced replication stress through gain of a copy of RAD21, and deleting one copy of RAD21 in trisomy 8 cells largely neutralizes the fitness benefit of chromosome 8 gain and reduces tumorgenicity of a Ewing sarcoma cancer cell line in soft agar assays. Aneuploidy, defined as whole-chromosome gain or loss, causes cellular stress but, paradoxically, is a frequent occurrence in cancers. Here, we investigate why ∼50% of Ewing sarcomas, driven by the EWS-FLI1 fusion oncogene, harbor chromosome 8 gains. Expression of the EWS-FLI1 fusion in primary cells causes replication stress that can result in cellular senescence. Using an evolution approach, we show that trisomy 8 mitigates EWS-FLI1-induced replication stress through gain of a copy of RAD21. Low-level ectopic expression of RAD21 is sufficient to dampen replication stress and improve proliferation in EWS-FLI1-expressing cells. Conversely, deleting one copy in trisomy 8 cells largely neutralizes the fitness benefit of chromosome 8 gain and reduces tumorgenicity of a Ewing sarcoma cancer cell line in soft agar assays. We propose that RAD21 promotes tumorigenesis through single gene copy gain. Such genes may explain some recurrent aneuploidies in cancer.
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Affiliation(s)
- Xiaofeng A Su
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Duanduan Ma
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility, Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - James V Parsons
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - John M Replogle
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - James F Amatruda
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Charles A Whittaker
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility, Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kimberly Stegmaier
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.,The Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Angelika Amon
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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31
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Chan CY, Tan KV, Cornelissen B. PARP Inhibitors in Cancer Diagnosis and Therapy. Clin Cancer Res 2021; 27:1585-1594. [PMID: 33082213 DOI: 10.1158/1078-0432.ccr-20-2766] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/07/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022]
Abstract
Targeting of PARP enzymes has emerged as an effective therapeutic strategy to selectively target cancer cells with deficiencies in homologous recombination signaling. Currently used to treat BRCA-mutated cancers, PARP inhibitors (PARPi) have demonstrated improved outcome in various cancer types as single agents. Ongoing efforts have seen the exploitation of PARPi combination therapies, boosting patient responses as a result of drug synergisms. Despite great successes using PARPi therapy, selecting those patients who will benefit from single agent or combination therapy remains one of the major challenges. Numerous reports have demonstrated that the presence of a BRCA mutation does not always result in synthetic lethality with PARPi therapy in treatment-naïve tumors. Cancer cells can also develop resistance to PARPi therapy. Hence, combination therapy may significantly affect the treatment outcomes. In this review, we discuss the development and utilization of PARPi in different cancer types from preclinical models to clinical trials, provide a current overview of the potential uses of PARP imaging agents in cancer therapy, and discuss the use of radiolabeled PARPi as radionuclide therapies.
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Affiliation(s)
- Chung Ying Chan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Kel Vin Tan
- Department of Diagnostic Radiology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Bart Cornelissen
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom.
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32
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Kondratick CM, Washington MT, Spies M. Making Choices: DNA Replication Fork Recovery Mechanisms. Semin Cell Dev Biol 2020; 113:27-37. [PMID: 33967572 DOI: 10.1016/j.semcdb.2020.10.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DNA replication is laden with obstacles that slow, stall, collapse, and break DNA replication forks. At each obstacle, there is a decision to be made whether to bypass the lesion, repair or restart the damaged fork, or to protect stalled forks from further demise. Each "decision" draws upon multitude of proteins participating in various mechanisms that allow repair and restart of replication forks. Specific functions for many of these proteins have been described and an understanding of how they come together in supporting replication forks is starting to emerge. Many questions, however, remain regarding selection of the mechanisms that enable faithful genome duplication and how "normal" intermediates in these mechanisms are sometimes funneled into "rogue" processes that destabilize the genome and lead to cancer, cell death, and emergence of chemotherapeutic resistance. In this review we will discuss molecular mechanisms of DNA damage bypass and replication fork protection and repair. We will specifically focus on the key players that define which mechanism is employed including: PCNA and its control by posttranslational modifications, translesion synthesis DNA polymerases, molecular motors that catalyze reversal of stalled replication forks, proteins that antagonize fork reversal and protect reversed forks from nucleolytic degradation, and the machinery of homologous recombination that helps to reestablish broken forks. We will also discuss risks to genome integrity inherent in each of these mechanisms.
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Affiliation(s)
- Christine M Kondratick
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - M Todd Washington
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.,Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.,Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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33
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Cheng H, Zhang N, Pati D. Cohesin subunit RAD21: From biology to disease. Gene 2020; 758:144966. [PMID: 32687945 PMCID: PMC7949736 DOI: 10.1016/j.gene.2020.144966] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
RAD21 (also known as KIAA0078, NXP1, HR21, Mcd1, Scc1, and hereafter called RAD21), an essential gene, encodes a DNA double-strand break (DSB) repair protein that is evolutionarily conserved in all eukaryotes from budding yeast to humans. RAD21 protein is a structural component of the highly conserved cohesin complex consisting of RAD21, SMC1a, SMC3, and SCC3 [STAG1 (SA1) and STAG2 (SA2) in metazoans] proteins, involved in sister chromatid cohesion. This function is essential for proper chromosome segregation, post-replicative DNA repair, and prevention of inappropriate recombination between repetitive regions. In interphase, cohesin also functions in the control of gene expression by binding to numerous sites within the genome. In addition to playing roles in the normal cell cycle and DNA DSB repair, RAD21 is also linked to the apoptotic pathways. Germline heterozygous or homozygous missense mutations in RAD21 have been associated with human genetic disorders, including developmental diseases such as Cornelia de Lange syndrome (CdLS) and chronic intestinal pseudo-obstruction (CIPO) called Mungan syndrome, respectively, and collectively termed as cohesinopathies. Somatic mutations and amplification of the RAD21 have also been widely reported in both human solid and hematopoietic tumors. Considering the role of RAD21 in a broad range of cellular processes that are hot spots in neoplasm, it is not surprising that the deregulation of RAD21 has been increasingly evident in human cancers. Herein, we review the biology of RAD21 and the cellular processes that this important protein regulates and discuss the significance of RAD21 deregulation in cancer and cohesinopathies.
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Affiliation(s)
- Haizi Cheng
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Nenggang Zhang
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Debananda Pati
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States.
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34
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Martin JC, Hoegel TJ, Lynch ML, Woloszynska A, Melendy T, Ohm JE. Exploiting Replication Stress as a Novel Therapeutic Intervention. Mol Cancer Res 2020; 19:192-206. [PMID: 33020173 DOI: 10.1158/1541-7786.mcr-20-0651] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/01/2020] [Accepted: 09/29/2020] [Indexed: 11/16/2022]
Abstract
Ewing sarcoma is an aggressive pediatric tumor of the bone and soft tissue. The current standard of care is radiation and chemotherapy, and patients generally lack targeted therapies. One of the defining molecular features of this tumor type is the presence of significantly elevated levels of replication stress as compared with both normal cells and many other types of cancers, but the source of this stress is poorly understood. Tumors that harbor elevated levels of replication stress rely on the replication stress and DNA damage response pathways to retain viability. Understanding the source of the replication stress in Ewing sarcoma may reveal novel therapeutic targets. Ewing sarcomagenesis is complex, and in this review, we discuss the current state of our knowledge regarding elevated replication stress and the DNA damage response in Ewing sarcoma, one contributor to the disease process. We will also describe how these pathways are being successfully targeted therapeutically in other tumor types, and discuss possible novel, evidence-based therapeutic interventions in Ewing sarcoma. We hope that this consolidation will spark investigations that uncover new therapeutic targets and lead to the development of better treatment options for patients with Ewing sarcoma. IMPLICATIONS: This review uncovers new therapeutic targets in Ewing sarcoma and highlights replication stress as an exploitable vulnerability across multiple cancers.
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Affiliation(s)
- Jeffrey C Martin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Tamara J Hoegel
- Department of Pediatric Hematology and Oncology, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Miranda L Lynch
- Hauptman-Woodward Medical Research Institute, Buffalo, New York
| | - Anna Woloszynska
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Thomas Melendy
- Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York
| | - Joyce E Ohm
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
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35
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Pardo B, Moriel‐Carretero M, Vicat T, Aguilera A, Pasero P. Homologous recombination and Mus81 promote replication completion in response to replication fork blockage. EMBO Rep 2020; 21:e49367. [PMID: 32419301 PMCID: PMC7332989 DOI: 10.15252/embr.201949367] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 12/19/2022] Open
Abstract
Impediments to DNA replication threaten genome stability. The homologous recombination (HR) pathway has been involved in the restart of blocked replication forks. Here, we used a method to increase yeast cell permeability in order to study at the molecular level the fate of replication forks blocked by DNA topoisomerase I poisoning by camptothecin (CPT). Our results indicate that Rad52 and Rad51 HR factors are required to complete DNA replication in response to CPT. Recombination events occurring during S phase do not generally lead to the restart of DNA synthesis but rather protect blocked forks until they merge with convergent forks. This fusion generates structures requiring their resolution by the Mus81 endonuclease in G2 /M. At the global genome level, the multiplicity of replication origins in eukaryotic genomes and the fork protection mechanism provided by HR appear therefore to be essential to complete DNA replication in response to fork blockage.
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Affiliation(s)
- Benjamin Pardo
- Institut de Génétique HumaineUniversité de Montpellier‐CNRSMontpellierFrance
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - María Moriel‐Carretero
- Institut de Génétique HumaineUniversité de Montpellier‐CNRSMontpellierFrance
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
- Present address:
Centre de Recherche en Biologie cellulaire de MontpellierUniversité de Montpellier‐CNRSMontpellierFrance
| | - Thibaud Vicat
- Institut de Génétique HumaineUniversité de Montpellier‐CNRSMontpellierFrance
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - Philippe Pasero
- Institut de Génétique HumaineUniversité de Montpellier‐CNRSMontpellierFrance
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36
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Lawrimore CJ, Lawrimore J, He Y, Chavez S, Bloom K. Polymer perspective of genome mobilization. Mutat Res 2020; 821:111706. [PMID: 32516654 DOI: 10.1016/j.mrfmmm.2020.111706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 02/07/2023]
Abstract
Chromosome motion is an intrinsic feature of all DNA-based metabolic processes and is a particularly well-documented response to both DNA damage and repair. By using both biological and polymer physics approaches, many of the contributing factors of chromatin motility have been elucidated. These include the intrinsic properties of chromatin, such as stiffness, as well as the loop modulators condensin and cohesin. Various biological factors such as external tethering to nuclear domains, ATP-dependent processes, and nucleofilaments further impact chromatin motion. DNA damaging agents that induce double-stranded breaks also cause increased chromatin motion that is modulated by recruitment of repair and checkpoint proteins. Approaches that integrate biological experimentation in conjunction with models from polymer physics provide mechanistic insights into the role of chromatin dynamics in biological function. In this review we discuss the polymer models and the effects of both DNA damage and repair on chromatin motion as well as mechanisms that may underlie these effects.
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Affiliation(s)
- Colleen J Lawrimore
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Josh Lawrimore
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Yunyan He
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Sergio Chavez
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Kerry Bloom
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States.
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37
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Machour FE, Ayoub N. Transcriptional Regulation at DSBs: Mechanisms and Consequences. Trends Genet 2020; 36:981-997. [PMID: 32001024 DOI: 10.1016/j.tig.2020.01.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/31/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
Abstract
Defective double-strand break (DSB) repair leads to genomic instabilities that may augment carcinogenesis. DSBs trigger transient transcriptional silencing in the vicinity of transcriptionally active genes through multilayered processes instigated by Ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase (DNA-PK), and poly-(ADP-ribose) polymerase 1 (PARP1). Novel factors have been identified that ensure DSB-induced silencing via two distinct pathways: direct inhibition of RNA Polymerase II (Pol II) mediated by negative elongation factor (NELF), and histone code editing by CDYL1 and histone deacetylases (HDACs) that catalyze H3K27me3 and erase lysine crotonylation, respectively. Here, we highlight major advances in understanding the mechanisms underlying transcriptional silencing at DSBs, and discuss its functional implications on repair. Furthermore, we discuss consequential links between DSB-silencing factors and carcinogenesis and discuss the potential of exploiting them for targeted cancer therapy.
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Affiliation(s)
- Feras E Machour
- Department of Biology, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Nabieh Ayoub
- Department of Biology, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
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38
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Gómez-González B, Ortega P, Aguilera A. Histone deacetylases facilitate the accurate repair of broken forks. Mol Cell Oncol 2020; 7:1705731. [PMID: 32158920 DOI: 10.1080/23723556.2019.1705731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/12/2019] [Accepted: 12/13/2019] [Indexed: 10/25/2022]
Abstract
We have recently uncovered that loss of the yeast histone deacetylases Rpd3 (Reduced Potassium Dependency 3) and Hda1 (Histone DeAcetylase 3) affects the cohesion between sister chromatids thus impairing repair of DNA damage at replication forks and enhancing genetic instability. Here we discuss the possible implications of our findings given that histone deacetylases are a promising chemotherapeutic target often used in combination with DNA damaging agents.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
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39
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Hoch NC, Polo LM. ADP-ribosylation: from molecular mechanisms to human disease. Genet Mol Biol 2019; 43:e20190075. [PMID: 31930280 PMCID: PMC7198025 DOI: 10.1590/1678-4685-gmb-2019-0075] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/04/2019] [Indexed: 12/23/2022] Open
Abstract
Post-translational modification of proteins by ADP-ribosylation, catalysed by
poly (ADP-ribose) polymerases (PARPs) using NAD+ as a substrate,
plays central roles in DNA damage signalling and repair, modulates a range of
cellular signalling cascades and initiates programmed cell death by parthanatos.
Here, we present mechanistic aspects of ADP-ribose modification, PARP activation
and the cellular functions of ADP-ribose signalling, and discuss how this
knowledge is uncovering therapeutic avenues for the treatment of increasingly
prevalent human diseases such as cancer, ischaemic damage and
neurodegeneration.
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Affiliation(s)
- Nicolas C Hoch
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Luis M Polo
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, UK.,Institute of Histology and Embryology of Mendoza - CONICET, Mendoza, Argentina
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40
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Gaillard H, Santos-Pereira JM, Aguilera A. The Nup84 complex coordinates the DNA damage response to warrant genome integrity. Nucleic Acids Res 2019; 47:4054-4067. [PMID: 30715474 PMCID: PMC6486642 DOI: 10.1093/nar/gkz066] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/24/2019] [Accepted: 01/25/2019] [Indexed: 02/07/2023] Open
Abstract
DNA lesions interfere with cellular processes such as transcription and replication and need to be adequately resolved to warrant genome integrity. Beyond their primary role in molecule transport, nuclear pore complexes (NPCs) function in other processes such as transcription, nuclear organization and DNA double strand break (DSB) repair. Here we found that the removal of UV-induced DNA lesions by nucleotide excision repair (NER) is compromised in the absence of the Nup84 nuclear pore component. Importantly, nup84Δ cells show an exacerbated sensitivity to UV in early S phase and delayed replication fork progression, suggesting that unrepaired spontaneous DNA lesions persist during S phase. In addition, nup84Δ cells are defective in the repair of replication-born DSBs by sister chromatid recombination (SCR) and rely on post-replicative repair functions for normal proliferation, indicating dysfunctions in the cellular pathways that enable replication on damaged DNA templates. Altogether, our data reveal a central role of the NPC in the DNA damage response to facilitate replication progression through damaged DNA templates by promoting efficient NER and SCR and preventing chromosomal rearrangements.
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Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - José M Santos-Pereira
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
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41
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Ortega P, Gómez-González B, Aguilera A. Rpd3L and Hda1 histone deacetylases facilitate repair of broken forks by promoting sister chromatid cohesion. Nat Commun 2019; 10:5178. [PMID: 31729385 PMCID: PMC6858524 DOI: 10.1038/s41467-019-13210-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Genome stability involves accurate replication and DNA repair. Broken replication forks, such as those encountering a nick, lead to double strand breaks (DSBs), which are preferentially repaired by sister-chromatid recombination (SCR). To decipher the role of chromatin in eukaryotic DSB repair, here we analyze a collection of yeast chromatin-modifying mutants using a previously developed system for the molecular analysis of repair of replication-born DSBs by SCR based on a mini-HO site. We confirm the candidates through FLP-based systems based on a mutated version of the FLP flipase that causes nicks on either the leading or lagging DNA strands. We demonstrate that Rpd3L and Hda1 histone deacetylase (HDAC) complexes contribute to the repair of replication-born DSBs by facilitating cohesin loading, with no effect on other types of homology-dependent repair, thus preventing genome instability. We conclude that histone deacetylation favors general sister chromatid cohesion as a necessary step in SCR.
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Affiliation(s)
- Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain.
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain.
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42
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Krenning L, van den Berg J, Medema RH. Life or Death after a Break: What Determines the Choice? Mol Cell 2019; 76:346-358. [PMID: 31561953 DOI: 10.1016/j.molcel.2019.08.023] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/19/2019] [Accepted: 08/26/2019] [Indexed: 01/22/2023]
Abstract
DNA double-strand breaks (DSBs) pose a constant threat to genomic integrity. Such DSBs need to be repaired to preserve homeostasis at both the cellular and organismal levels. Hence, the DNA damage response (DDR) has evolved to repair these lesions and limit their toxicity. The initiation of DNA repair depends on the activation of the DDR, and we know that the strength of DDR signaling may differentially affect cellular viability. However, we do not fully understand what determines the cytotoxicity of a DSB. Recent work has identified genomic location, (in)correct DNA repair pathway usage, and cell-cycle position as contributors to DSB-induced cytotoxicity. In this review, we discuss how these determinants affect cytotoxicity, highlight recent discoveries, and identify open questions that could help to improve our understanding about cell fate decisions after a DNA DSB.
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Affiliation(s)
- Lenno Krenning
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Jeroen van den Berg
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - René H Medema
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands.
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43
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Abstract
Smc5 and Smc6, together with the kleisin Nse4, form the heart of the enigmatic and poorly understood Smc5/6 complex, which is frequently viewed as a cousin of cohesin and condensin with functions in DNA repair. As novel functions for cohesin and condensin complexes in the organization of long-range chromatin architecture have recently emerged, new unsuspected roles for Smc5/6 have also surfaced. Here, I aim to provide a comprehensive overview of our current knowledge of the Smc5/6 complex, including its long-established function in genome stability, its multiple roles in DNA repair, and its recently discovered connection to the transcription inhibition of hepatitis B virus genomes. In addition, I summarize new research that is beginning to tease out the molecular details of Smc5/6 structure and function, knowledge that will illuminate the nuclear activities of Smc5/6 in the stability and dynamics of eukaryotic genomes.
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Affiliation(s)
- Luis Aragón
- Cell Cycle Group, MRC London Institute of Medical Sciences, Hammersmith Hospital Campus, London W12 0NN, United Kingdom;
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44
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Hanzlikova H, Caldecott KW. Perspectives on PARPs in S Phase. Trends Genet 2019; 35:412-422. [PMID: 31036342 DOI: 10.1016/j.tig.2019.03.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/28/2019] [Accepted: 03/28/2019] [Indexed: 01/08/2023]
Abstract
Accurate copying of DNA during S phase is essential for genome stability and cell viability. During genome duplication, the progression of the DNA replication machinery is challenged by limitations in nucleotide supply and physical barriers in the DNA template that include naturally occurring DNA lesions and secondary structures that are difficult to replicate. To ensure correct and complete replication of the genome, cells have evolved several mechanisms that protect DNA replication forks and thus maintain genome integrity and stability during S phase. One class of enzymes that have recently emerged as important in this process, and therefore as promising targets in anticancer therapy, are the poly(ADP-ribose) polymerases (PARPs). We review here the roles of these enzymes during DNA replication as well as their impact on genome stability and cellular viability in normal and cancer cells.
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Affiliation(s)
- Hana Hanzlikova
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, 4, Czech Republic.
| | - Keith W Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142 20 Prague, 4, Czech Republic.
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45
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Cabezas M, García-Quevedo L, Alonso C, Manubens M, Álvarez Y, Barquinero JF, Ramón Y Cajal S, Ortega M, Blanco A, Caballín MR, Armengol G. Polymorphisms in MDM2 and TP53 Genes and Risk of Developing Therapy-Related Myeloid Neoplasms. Sci Rep 2019; 9:150. [PMID: 30655613 PMCID: PMC6336808 DOI: 10.1038/s41598-018-36931-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 11/22/2018] [Indexed: 12/28/2022] Open
Abstract
One of the most severe complications after successful cancer therapy is the development of therapy-related myeloid neoplasms (t-MN). Constitutional genetic variation is likely to impact on t-MN risk. We aimed to evaluate if polymorphisms in the p53 pathway can be useful for predicting t-MN susceptibility. First, an association study revealed that the Pro variant of the TP53 Arg72Pro polymorphism and the G allele of the MDM2 SNP309 were associated with t-MN risk. The Arg variant of TP53 is more efficient at inducing apoptosis, whereas the Pro variant is a more potent inductor of cell cycle arrest and DNA repair. As regards MDM2 SNP309, the G allele is associated with attenuation of the p53 apoptotic response. Second, to evaluate the biological effect of the TP53 polymorphism, we established Jurkat isogenic cell lines expressing p53Arg or p53Pro. Jurkat p53Arg cells presented higher DNA damage and higher apoptotic potential than p53Pro cells, after treatment with chemotherapy agents. Only p53Pro cells presented t(15;17) translocation and del(5q). We suggest that failure to repair DNA lesions in p53Arg cells would lead them to apoptosis, whereas some p53Pro cells, prone to cell cycle arrest and DNA repair, could undergo misrepair, generating chromosomal abnormalities typical of t-MN.
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Affiliation(s)
- Maria Cabezas
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Lydia García-Quevedo
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Cintia Alonso
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Marta Manubens
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Yolanda Álvarez
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Joan Francesc Barquinero
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Santiago Ramón Y Cajal
- Department of Pathology, Vall d'Hebron University Hospital, 08035, Barcelona, Catalonia, Spain.,Spanish Biomedical Research Network Centre in Oncology (CIBERONC), Barcelona, Catalonia, Spain
| | - Margarita Ortega
- Department of Hematology, Vall d'Hebron University Hospital, 08035, Barcelona, Catalonia, Spain
| | - Adoración Blanco
- Department of Hematology, Vall d'Hebron University Hospital, 08035, Barcelona, Catalonia, Spain
| | - María Rosa Caballín
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Gemma Armengol
- Unit of Biological Anthropology, Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain.
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46
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Klein HL, Bačinskaja G, Che J, Cheblal A, Elango R, Epshtein A, Fitzgerald DM, Gómez-González B, Khan SR, Kumar S, Leland BA, Marie L, Mei Q, Miné-Hattab J, Piotrowska A, Polleys EJ, Putnam CD, Radchenko EA, Saada AA, Sakofsky CJ, Shim EY, Stracy M, Xia J, Yan Z, Yin Y, Aguilera A, Argueso JL, Freudenreich CH, Gasser SM, Gordenin DA, Haber JE, Ira G, Jinks-Robertson S, King MC, Kolodner RD, Kuzminov A, Lambert SAE, Lee SE, Miller KM, Mirkin SM, Petes TD, Rosenberg SM, Rothstein R, Symington LS, Zawadzki P, Kim N, Lisby M, Malkova A. Guidelines for DNA recombination and repair studies: Cellular assays of DNA repair pathways. MICROBIAL CELL (GRAZ, AUSTRIA) 2019; 6:1-64. [PMID: 30652105 PMCID: PMC6334234 DOI: 10.15698/mic2019.01.664] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/29/2018] [Accepted: 09/14/2018] [Indexed: 12/29/2022]
Abstract
Understanding the plasticity of genomes has been greatly aided by assays for recombination, repair and mutagenesis. These assays have been developed in microbial systems that provide the advantages of genetic and molecular reporters that can readily be manipulated. Cellular assays comprise genetic, molecular, and cytological reporters. The assays are powerful tools but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.
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Affiliation(s)
- Hannah L. Klein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Giedrė Bačinskaja
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Jun Che
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA
| | - Anais Cheblal
- Friedrich Miescher Institute for Biomedical Research (FMI), 4058 Basel, Switzerland
| | - Rajula Elango
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Anastasiya Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Devon M. Fitzgerald
- Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Belén Gómez-González
- Centro Andaluz de BIología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, Seville, Spain
| | - Sharik R. Khan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Sandeep Kumar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | - Léa Marie
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Qian Mei
- Systems, Synthetic and Physical Biology Graduate Program, Rice University, Houston, TX, USA
| | - Judith Miné-Hattab
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France
- Sorbonne Université, Institut Curie, CNRS, UMR3664, F-75005 Paris, France
| | - Alicja Piotrowska
- NanoBioMedical Centre, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | | | - Christopher D. Putnam
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, La Jolla, CA, USA
- Department of Medicine, University of California School of Medicine, San Diego, La Jolla, CA, USA
| | | | - Anissia Ait Saada
- Institut Curie, PSL Research University, CNRS, UMR3348 F-91405, Orsay, France
- University Paris Sud, Paris-Saclay University, CNRS, UMR3348, F-91405, Orsay, France
| | - Cynthia J. Sakofsky
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, USA
| | - Eun Yong Shim
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA
| | - Mathew Stracy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Jun Xia
- Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Zhenxin Yan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Yi Yin
- Department of Molecular Genetics and Microbiology and University Program in Genetics and Genomics, Duke University Medical Center, Durham, NC USA
| | - Andrés Aguilera
- Centro Andaluz de BIología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, Seville, Spain
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Catherine H. Freudenreich
- Department of Biology, Tufts University, Medford, MA USA
- Program in Genetics, Tufts University, Boston, MA, USA
| | - Susan M. Gasser
- Friedrich Miescher Institute for Biomedical Research (FMI), 4058 Basel, Switzerland
| | - Dmitry A. Gordenin
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, USA
| | - James E. Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, USA
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sue Jinks-Robertson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC USA
| | | | - Richard D. Kolodner
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California School of Medicine, San Diego, La Jolla, CA, USA
- Moores-UCSD Cancer Center, University of California School of Medicine, San Diego, La Jolla, CA, USA
- Institute of Genomic Medicine, University of California School of Medicine, San Diego, La Jolla, CA, USA
| | - Andrei Kuzminov
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Sarah AE Lambert
- Institut Curie, PSL Research University, CNRS, UMR3348 F-91405, Orsay, France
- University Paris Sud, Paris-Saclay University, CNRS, UMR3348, F-91405, Orsay, France
| | - Sang Eun Lee
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, USA
| | - Kyle M. Miller
- Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | | | - Thomas D. Petes
- Department of Molecular Genetics and Microbiology and University Program in Genetics and Genomics, Duke University Medical Center, Durham, NC USA
| | - Susan M. Rosenberg
- Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Systems, Synthetic and Physical Biology Graduate Program, Rice University, Houston, TX, USA
| | - Rodney Rothstein
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Lorraine S. Symington
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Pawel Zawadzki
- NanoBioMedical Centre, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - Nayun Kim
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Michael Lisby
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Anna Malkova
- Department of Biology, University of Iowa, Iowa City, IA, USA
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47
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Bouwman BAM, Crosetto N. Endogenous DNA Double-Strand Breaks during DNA Transactions: Emerging Insights and Methods for Genome-Wide Profiling. Genes (Basel) 2018; 9:E632. [PMID: 30558210 PMCID: PMC6316733 DOI: 10.3390/genes9120632] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) jeopardize genome integrity and can-when repaired unfaithfully-give rise to structural rearrangements associated with cancer. Exogenous agents such as ionizing radiation or chemotherapy can invoke DSBs, but a vast amount of breakage arises during vital endogenous DNA transactions, such as replication and transcription. Additionally, chromatin looping involved in 3D genome organization and gene regulation is increasingly recognized as a possible contributor to DSB events. In this review, we first discuss insights into the mechanisms of endogenous DSB formation, showcasing the trade-off between essential DNA transactions and the intrinsic challenges that these processes impose on genomic integrity. In the second part, we highlight emerging methods for genome-wide profiling of DSBs, and discuss future directions of research that will help advance our understanding of genome-wide DSB formation and repair.
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Affiliation(s)
- Britta A M Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
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Litwin I, Pilarczyk E, Wysocki R. The Emerging Role of Cohesin in the DNA Damage Response. Genes (Basel) 2018; 9:genes9120581. [PMID: 30487431 PMCID: PMC6316000 DOI: 10.3390/genes9120581] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/23/2022] Open
Abstract
Faithful transmission of genetic material is crucial for all organisms since changes in genetic information may result in genomic instability that causes developmental disorders and cancers. Thus, understanding the mechanisms that preserve genome integrity is of fundamental importance. Cohesin is a multiprotein complex whose canonical function is to hold sister chromatids together from S-phase until the onset of anaphase to ensure the equal division of chromosomes. However, recent research points to a crucial function of cohesin in the DNA damage response (DDR). In this review, we summarize recent advances in the understanding of cohesin function in DNA damage signaling and repair. First, we focus on cohesin architecture and molecular mechanisms that govern sister chromatid cohesion. Next, we briefly characterize the main DDR pathways. Finally, we describe mechanisms that determine cohesin accumulation at DNA damage sites and discuss possible roles of cohesin in DDR.
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Affiliation(s)
- Ireneusz Litwin
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
| | - Ewa Pilarczyk
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
| | - Robert Wysocki
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland.
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Hossain MA, Lin Y, Yan S. Single-Strand Break End Resection in Genome Integrity: Mechanism and Regulation by APE2. Int J Mol Sci 2018; 19:ijms19082389. [PMID: 30110897 PMCID: PMC6122073 DOI: 10.3390/ijms19082389] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/07/2018] [Accepted: 08/11/2018] [Indexed: 12/22/2022] Open
Abstract
DNA single-strand breaks (SSBs) occur more than 10,000 times per mammalian cell each day, representing the most common type of DNA damage. Unrepaired SSBs compromise DNA replication and transcription programs, leading to genome instability. Unrepaired SSBs are associated with diseases such as cancer and neurodegenerative disorders. Although canonical SSB repair pathway is activated to repair most SSBs, it remains unclear whether and how unrepaired SSBs are sensed and signaled. In this review, we propose a new concept of SSB end resection for genome integrity. We propose a four-step mechanism of SSB end resection: SSB end sensing and processing, as well as initiation, continuation, and termination of SSB end resection. We also compare different mechanisms of SSB end resection and DSB end resection in DNA repair and DNA damage response (DDR) pathways. We further discuss how SSB end resection contributes to SSB signaling and repair. We focus on the mechanism and regulation by APE2 in SSB end resection in genome integrity. Finally, we identify areas of future study that may help us gain further mechanistic insight into the process of SSB end resection. Overall, this review provides the first comprehensive perspective on SSB end resection in genome integrity.
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Affiliation(s)
- Md Akram Hossain
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
| | - Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
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Abstract
PURPOSE OF REVIEW Disturbance of the delicate balance between self-renewal and differentiation in haematopoietic stem cells (HSCs) can lead to both leukaemia and bone marrow failure. The regulation of this balance in HSC biology has been intensely investigated in several model systems, and lately the importance of epigenetic modifications as well as the organization and architecture of chromatin has become increasingly recognized. In this review, we will focus on the role of the chromatin organizing protein complex cohesin in regulation of normal and malignant haematopoiesis. RECENT FINDINGS Several functional studies in both mouse and human systems have implicated cohesin as a critical regulator of self-renewal and differentiation in HSCs. Together with the discovery of recurrent mutations of cohesin genes in myeloid malignancies, this points towards a direct role of perturbed cohesin function in leukemogenesis. SUMMARY The work reviewed here provides new insights about the role of the cohesin complex and chromatin architecture in normal and malignant HSCs, and indicates how cohesin may be specifically targeted for therapeutic benefit in the future.
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Affiliation(s)
- Roman Galeev
- Division of Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
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