1
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Keszthelyi A, Mansoubi S, Whale A, Houseley J, Baxter J. The fork protection complex generates DNA topological stress-induced DNA damage while ensuring full and faithful genome duplication. Proc Natl Acad Sci U S A 2024; 121:e2413631121. [PMID: 39589889 PMCID: PMC11626154 DOI: 10.1073/pnas.2413631121] [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: 07/08/2024] [Accepted: 10/14/2024] [Indexed: 11/28/2024] Open
Abstract
The fork protection complex (FPC), composed of Mrc1, Tof1, and Csm3, supports rapid and stable DNA replication. Here, we show that FPC activity also introduces DNA damage by increasing DNA topological stress during replication. Mrc1 action increases DNA topological stress during plasmid replication, while Mrc1 or Tof1 activity causes replication stress and DNA damage within topologically constrained regions. We show that the recruitment of Top1 to the fork by Tof1 suppresses the DNA damage generated in these loci. While FPC activity introduces some DNA damage due to increased topological stress, the FPC is also necessary to prevent DNA damage in long replicons across the genome, indicating that the FPC is required for complete and faithful genome duplication. We conclude that FPC regulation must balance ensuring full genome duplication through rapid replication with minimizing the consequential DNA topological stress-induced DNA damage caused by rapid replication through constrained regions.
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Affiliation(s)
- Andrea Keszthelyi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, East SussexBN1 9RQ, United Kingdom
| | - Sahar Mansoubi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, East SussexBN1 9RQ, United Kingdom
- Biology Department, North Tehran Branch, Islamic Azad University, Tehran1477893855, Iran
| | - Alex Whale
- Epigenetics Programme The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, United Kingdom
| | - Jonathan Houseley
- Epigenetics Programme The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, United Kingdom
| | - Jonathan Baxter
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, East SussexBN1 9RQ, United Kingdom
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2
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Westhorpe R, Roske JJ, Yeeles JTP. Mechanisms controlling replication fork stalling and collapse at topoisomerase 1 cleavage complexes. Mol Cell 2024; 84:3469-3481.e7. [PMID: 39236719 PMCID: PMC7617106 DOI: 10.1016/j.molcel.2024.08.004] [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: 03/08/2024] [Revised: 06/14/2024] [Accepted: 08/02/2024] [Indexed: 09/07/2024]
Abstract
Topoisomerase 1 cleavage complexes (Top1-ccs) comprise a DNA-protein crosslink and a single-stranded DNA break that can significantly impact the DNA replication machinery (replisome). Consequently, inhibitors that trap Top1-ccs are used extensively in research and clinical settings to generate DNA replication stress, yet how the replisome responds upon collision with a Top1-cc remains obscure. By reconstituting collisions between budding yeast replisomes, assembled from purified proteins, and site-specific Top1-ccs, we have uncovered mechanisms underlying replication fork stalling and collapse. We find that stalled replication forks are surprisingly stable and that their stability is influenced by the template strand that Top1 is crosslinked to, the fork protection complex proteins Tof1-Csm3 (human TIMELESS-TIPIN), and the convergence of replication forks. Moreover, nascent-strand mapping and cryoelectron microscopy (cryo-EM) of stalled forks establishes replisome remodeling as a key factor in the initial response to Top1-ccs. These findings have important implications for the use of Top1 inhibitors in research and in the clinic.
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Affiliation(s)
- Rose Westhorpe
- Protein and Nucleic Acid Chemistry Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Johann J Roske
- Protein and Nucleic Acid Chemistry Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Joseph T P Yeeles
- Protein and Nucleic Acid Chemistry Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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3
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Charlton SJ, Flury V, Kanoh Y, Genzor AV, Kollenstart L, Ao W, Brøgger P, Weisser MB, Adamus M, Alcaraz N, Delvaux de Fenffe CM, Mattiroli F, Montoya G, Masai H, Groth A, Thon G. The fork protection complex promotes parental histone recycling and epigenetic memory. Cell 2024; 187:5029-5047.e21. [PMID: 39094569 PMCID: PMC11383432 DOI: 10.1016/j.cell.2024.07.017] [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: 08/30/2023] [Revised: 03/16/2024] [Accepted: 07/09/2024] [Indexed: 08/04/2024]
Abstract
The inheritance of parental histones across the replication fork is thought to mediate epigenetic memory. Here, we reveal that fission yeast Mrc1 (CLASPIN in humans) binds H3-H4 tetramers and operates as a central coordinator of symmetric parental histone inheritance. Mrc1 mutants in a key connector domain disrupted segregation of parental histones to the lagging strand comparable to Mcm2 histone-binding mutants. Both mutants showed clonal and asymmetric loss of H3K9me-mediated gene silencing. AlphaFold predicted co-chaperoning of H3-H4 tetramers by Mrc1 and Mcm2, with the Mrc1 connector domain bridging histone and Mcm2 binding. Biochemical and functional analysis validated this model and revealed a duality in Mrc1 function: disabling histone binding in the connector domain disrupted lagging-strand recycling while another histone-binding mutation impaired leading strand recycling. We propose that Mrc1 toggles histones between the lagging and leading strand recycling pathways, in part by intra-replisome co-chaperoning, to ensure epigenetic transmission to both daughter cells.
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Affiliation(s)
- Sebastian Jespersen Charlton
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark; Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Valentin Flury
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Yutaka Kanoh
- Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | | | - Leonie Kollenstart
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Wantong Ao
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Peter Brøgger
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Melanie Bianca Weisser
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Marek Adamus
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Nicolas Alcaraz
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | | | - Francesca Mattiroli
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Utrecht, The Netherlands
| | - Guillermo Montoya
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Hisao Masai
- Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Anja Groth
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark; Biotech Research & Innovation Centre, University of Copenhagen, Copenhagen 2200, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark.
| | - Geneviève Thon
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark.
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4
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Petropoulos M, Karamichali A, Rossetti GG, Freudenmann A, Iacovino LG, Dionellis VS, Sotiriou SK, Halazonetis TD. Transcription-replication conflicts underlie sensitivity to PARP inhibitors. Nature 2024; 628:433-441. [PMID: 38509368 PMCID: PMC11006605 DOI: 10.1038/s41586-024-07217-2] [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: 12/14/2022] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
An important advance in cancer therapy has been the development of poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of homologous recombination (HR)-deficient cancers1-6. PARP inhibitors trap PARPs on DNA. The trapped PARPs are thought to block replisome progression, leading to formation of DNA double-strand breaks that require HR for repair7. Here we show that PARP1 functions together with TIMELESS and TIPIN to protect the replisome in early S phase from transcription-replication conflicts. Furthermore, the synthetic lethality of PARP inhibitors with HR deficiency is due to an inability to repair DNA damage caused by transcription-replication conflicts, rather than by trapped PARPs. Along these lines, inhibiting transcription elongation in early S phase rendered HR-deficient cells resistant to PARP inhibitors and depleting PARP1 by small-interfering RNA was synthetic lethal with HR deficiency. Thus, inhibiting PARP1 enzymatic activity may suffice for treatment efficacy in HR-deficient settings.
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Affiliation(s)
- Michalis Petropoulos
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Angeliki Karamichali
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | | | - Alena Freudenmann
- FoRx Therapeutics AG, Basel, Switzerland
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | | | - Vasilis S Dionellis
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Sotirios K Sotiriou
- FoRx Therapeutics AG, Basel, Switzerland
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Thanos D Halazonetis
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
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5
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Cook D, Kozmin SG, Yeh E, Petes TD, Bloom K. Dicentric chromosomes are resolved through breakage and repair at their centromeres. Chromosoma 2024; 133:117-134. [PMID: 38165460 PMCID: PMC11180013 DOI: 10.1007/s00412-023-00814-6] [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: 11/07/2023] [Revised: 11/11/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Chromosomes with two centromeres provide a unique opportunity to study chromosome breakage and DNA repair using completely endogenous cellular machinery. Using a conditional transcriptional promoter to control the second centromere, we are able to activate the dicentric chromosome and follow the appearance of DNA repair products. We find that the rate of appearance of DNA repair products resulting from homology-based mechanisms exceeds the expected rate based on their limited centromere homology (340 bp) and distance from one another (up to 46.3 kb). In order to identify whether DNA breaks originate in the centromere, we introduced 12 single-nucleotide polymorphisms (SNPs) into one of the centromeres. Analysis of the distribution of SNPs in the recombinant centromeres reveals that recombination was initiated with about equal frequency within the conserved centromere DNA elements CDEII and CDEIII of the two centromeres. The conversion tracts range from about 50 bp to the full length of the homology between the two centromeres (340 bp). Breakage and repair events within and between the centromeres can account for the efficiency and distribution of DNA repair products. We propose that in addition to providing a site for kinetochore assembly, the centromere may be a point of stress relief in the face of genomic perturbations.
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Affiliation(s)
- Diana Cook
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA
| | - Stanislav G Kozmin
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Elaine Yeh
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA
| | - Thomas D Petes
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kerry Bloom
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA.
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6
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Piguet B, Houseley J. Transcription as source of genetic heterogeneity in budding yeast. Yeast 2024; 41:171-185. [PMID: 38196235 DOI: 10.1002/yea.3926] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/10/2023] [Accepted: 12/20/2023] [Indexed: 01/11/2024] Open
Abstract
Transcription presents challenges to genome stability both directly, by altering genome topology and exposing single-stranded DNA to chemical insults and nucleases, and indirectly by introducing obstacles to the DNA replication machinery. Such obstacles include the RNA polymerase holoenzyme itself, DNA-bound regulatory factors, G-quadruplexes and RNA-DNA hybrid structures known as R-loops. Here, we review the detrimental impacts of transcription on genome stability in budding yeast, as well as the mitigating effects of transcription-coupled nucleotide excision repair and of systems that maintain DNA replication fork processivity and integrity. Interactions between DNA replication and transcription have particular potential to induce mutation and structural variation, but we conclude that such interactions must have only minor effects on DNA replication by the replisome with little if any direct mutagenic outcome. However, transcription can significantly impair the fidelity of replication fork rescue mechanisms, particularly Break Induced Replication, which is used to restart collapsed replication forks when other means fail. This leads to de novo mutations, structural variation and extrachromosomal circular DNA formation that contribute to genetic heterogeneity, but only under particular conditions and in particular genetic contexts, ensuring that the bulk of the genome remains extremely stable despite the seemingly frequent interactions between transcription and DNA replication.
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7
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Vipat S, Moiseeva TN. The TIMELESS Roles in Genome Stability and Beyond. J Mol Biol 2024; 436:168206. [PMID: 37481157 DOI: 10.1016/j.jmb.2023.168206] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/20/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
TIMELESS protein (TIM) protects replication forks from stalling at difficult-to-replicate regions and plays an important role in DNA damage response, including checkpoint signaling, protection of stalled replication forks and DNA repair. Loss of TIM causes severe replication stress, while its overexpression is common in various types of cancer, providing protection from DNA damage and resistance to chemotherapy. Although TIM has mostly been studied for its part in replication stress response, its additional roles in supporting genome stability and a wide variety of other cellular pathways are gradually coming to light. This review discusses the diverse functions of TIM and its orthologs in healthy and cancer cells, open questions, and potential future directions.
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Affiliation(s)
- Sameera Vipat
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn 12618, Estonia
| | - Tatiana N Moiseeva
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn 12618, Estonia.
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8
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Lewis JS, van Oijen AM, Spenkelink LM. Embracing Heterogeneity: Challenging the Paradigm of Replisomes as Deterministic Machines. Chem Rev 2023; 123:13419-13440. [PMID: 37971892 PMCID: PMC10790245 DOI: 10.1021/acs.chemrev.3c00436] [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: 06/25/2023] [Revised: 10/15/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
The paradigm of cellular systems as deterministic machines has long guided our understanding of biology. Advancements in technology and methodology, however, have revealed a world of stochasticity, challenging the notion of determinism. Here, we explore the stochastic behavior of multi-protein complexes, using the DNA replication system (replisome) as a prime example. The faithful and timely copying of DNA depends on the simultaneous action of a large set of enzymes and scaffolding factors. This fundamental cellular process is underpinned by dynamic protein-nucleic acid assemblies that must transition between distinct conformations and compositional states. Traditionally viewed as a well-orchestrated molecular machine, recent experimental evidence has unveiled significant variability and heterogeneity in the replication process. In this review, we discuss recent advances in single-molecule approaches and single-particle cryo-EM, which have provided insights into the dynamic processes of DNA replication. We comment on the new challenges faced by structural biologists and biophysicists as they attempt to describe the dynamic cascade of events leading to replisome assembly, activation, and progression. The fundamental principles uncovered and yet to be discovered through the study of DNA replication will inform on similar operating principles for other multi-protein complexes.
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Affiliation(s)
- Jacob S. Lewis
- Macromolecular
Machines Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Antoine M. van Oijen
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Lisanne M. Spenkelink
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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9
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Mertz TM, Rice-Reynolds E, Nguyen L, Wood A, Cordero C, Bray N, Harcy V, Vyas RK, Mitchell D, Lobachev K, Roberts SA. Genetic inhibitors of APOBEC3B-induced mutagenesis. Genome Res 2023; 33:1568-1581. [PMID: 37532520 PMCID: PMC10620048 DOI: 10.1101/gr.277430.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 07/27/2023] [Indexed: 08/04/2023]
Abstract
The cytidine deaminases APOBEC3A (A3A) and APOBEC3B (A3B) are prominent mutators of human cancer genomes. However, tumor-specific genetic modulators of APOBEC-induced mutagenesis are poorly defined. Here, we used a screen to identify 61 gene deletions that increase A3B-induced mutations in yeast. We also determined whether each deletion was epistatic with Ung1 loss, which indicated whether the encoded factors participate in the homologous recombination (HR)-dependent bypass of A3B/Ung1-dependent abasic sites or suppress A3B-catalyzed deamination by protecting against aberrant formation of single-stranded DNA (ssDNA). We found that the mutation spectra of A3B-induced mutations revealed genotype-specific patterns of strand-specific ssDNA formation and nucleotide incorporation across APOBEC-induced lesions. Combining these three metrics, we were able to establish a multifactorial signature of APOBEC-induced mutations specific to (1) failure to remove H3K56 acetylation, (2) defective CTF18-RFC complex function, and (3) defective HR-mediated bypass of APOBEC-induced lesions. We extended these results by analyzing mutation data for human tumors and found BRCA1/2-deficient breast cancers display three- to fourfold more APOBEC-induced mutations. Mirroring our results in yeast, Rev1-mediated C-to-G substitutions are mainly responsible for increased APOBEC-signature mutations in BRCA1/2-deficient tumors, and these mutations associate with lagging strand synthesis during replication. These results identify important factors that influence DNA replication dynamics and likely the abundance of APOBEC-induced mutation during tumor progression. They also highlight a novel role for BRCA1/2 during HR-dependent lesion bypass of APOBEC-induced lesions during cancer cell replication.
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Affiliation(s)
- Tony M Mertz
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA;
- Department of Microbiology and Molecular Genetics, University of Vermont Cancer Center, University of Vermont, Burlington, Vermont 05405, USA
| | - Elizabeth Rice-Reynolds
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Ly Nguyen
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Anna Wood
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Cameron Cordero
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
- Department of Microbiology and Molecular Genetics, University of Vermont Cancer Center, University of Vermont, Burlington, Vermont 05405, USA
| | - Nicholas Bray
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Victoria Harcy
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Rudri K Vyas
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
- Department of Microbiology and Molecular Genetics, University of Vermont Cancer Center, University of Vermont, Burlington, Vermont 05405, USA
| | - Debra Mitchell
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
| | - Kirill Lobachev
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Steven A Roberts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA;
- Department of Microbiology and Molecular Genetics, University of Vermont Cancer Center, University of Vermont, Burlington, Vermont 05405, USA
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10
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Pellegrini L. The CMG DNA helicase and the core replisome. Curr Opin Struct Biol 2023; 81:102612. [PMID: 37244171 DOI: 10.1016/j.sbi.2023.102612] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/29/2023]
Abstract
Eukaryotic DNA replication is performed by the replisome, a large and dynamic multi-protein machine endowed with the required enzymatic components for the synthesis of new DNA. Recent cryo-electron microscopy (cryoEM) analyses have revealed the conserved architecture of the core eukaryotic replisome, comprising the CMG (Cdc45-MCM-GINS) DNA helicase, the leading-strand DNA polymerase epsilon, the Timeless-Tipin heterodimer, the hub protein AND-1 and the checkpoint protein Claspin. These results bid well for arriving soon at an integrated understanding of the structural basis of semi-discontinuous DNA replication. They further set the scene for the characterisation of the mechanisms that interface DNA synthesis with concurrent processes such as DNA repair, propagation of chromatin structure and establishment of sister chromatid cohesion.
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11
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Mertz TM, Rice-Reynolds E, Nguyen L, Wood A, Bray N, Mitchell D, Lobachev K, Roberts SA. Genetic modifiers of APOBEC-induced mutagenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.05.535598. [PMID: 37066362 PMCID: PMC10104050 DOI: 10.1101/2023.04.05.535598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The cytidine deaminases APOBEC3A and APOBEC3B (A3B) are prominent mutators of human cancer genomes. However, tumor-specific genetic modulators of APOBEC-induced mutagenesis are poorly defined. Here, we utilized a screen to identify 61 gene deletions that increase A3B-induced mutations in yeast. Also, we determined whether each deletion was epistatic with UNG1 loss, which indicated whether the encoded factors participate in the error-free bypass of A3B/Ung1-dependent abasic sites or suppress A3B-catalyzed deamination by protecting against aberrant formation of single stranded DNA (ssDNA). Additionally, we determined that the mutation spectra of A3B-induced mutations revealed genotype-specific patterns of strand-specific ssDNA formation and nucleotide incorporation across APOBEC-induced lesions. Combining these three metrics we were able to establish a multifactorial signature of APOBEC-induced mutations specific to (1) failure to remove H3K56 acetylation, which results in extremely high A3B-induced mutagenesis, (2) defective CTF18-RFC complex function, which results in high levels of A3B induced mutations specifically on the leading strand template that synergistically increase with loss of UNG1, and (3) defective HR-mediated bypass of APOBEC-induced lesions, which were epistatic with Ung1 loss and result from increased Rev1-mediated C-to-G substitutions. We extended these results by analyzing mutation data for human tumors and found BRCA1/2-deficient breast cancer tumors display 3- to 4-fold more APOBEC-induced mutations. Mirroring our results in yeast, for BRCA1/2 deficient tumors Rev1-mediated C-to-G substitutions are solely responsible for increased APOBEC-signature mutations and these mutations occur on the lagging strand during DNA replication. Together these results identify important factors that influence the dynamics of DNA replication and likely the abundance of APOBEC-induced mutation during tumor progression as well as a novel mechanistic role for BRCA1/2 during HR-dependent lesion bypass of APOBEC-induced lesions during cancer cell replication.
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12
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Patel JA, Kim H. The TIMELESS effort for timely DNA replication and protection. Cell Mol Life Sci 2023; 80:84. [PMID: 36892674 PMCID: PMC9998586 DOI: 10.1007/s00018-023-04738-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 03/10/2023]
Abstract
Accurate replication of the genome is fundamental to cellular survival and tumor prevention. The DNA replication fork is vulnerable to DNA lesions and damages that impair replisome progression, and improper control over DNA replication stress inevitably causes fork stalling and collapse, a major source of genome instability that fuels tumorigenesis. The integrity of the DNA replication fork is maintained by the fork protection complex (FPC), in which TIMELESS (TIM) constitutes a key scaffold that couples the CMG helicase and replicative polymerase activities, in conjunction with its interaction with other proteins associated with the replication machinery. Loss of TIM or the FPC in general results in impaired fork progression, elevated fork stalling and breakage, and a defect in replication checkpoint activation, thus underscoring its pivotal role in protecting the integrity of both active and stalled replication forks. TIM is upregulated in multiple cancers, which may represent a replication vulnerability of cancer cells that could be exploited for new therapies. Here, we discuss recent advances on our understanding of the multifaceted roles of TIM in DNA replication and stalled fork protection, and how its complex functions are engaged in collaboration with other genome surveillance and maintenance factors.
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Affiliation(s)
- Jinal A Patel
- Department of Pharmacological Sciences, State University of New York at Stony Brook, Basic Sciences Tower 8-125, 101 Nicolls Rd, Stony Brook, NY, 11794, USA
| | - Hyungjin Kim
- Department of Pharmacological Sciences, State University of New York at Stony Brook, Basic Sciences Tower 8-125, 101 Nicolls Rd, Stony Brook, NY, 11794, USA.
- Stony Brook Cancer Center and Renaissance School of Medicine, Stony Brook University, Basic Sciences Tower 8-125, 101 Nicolls Rd, Stony Brook, NY, 11794, USA.
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13
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Theulot B, Lacroix L, Arbona JM, Millot GA, Jean E, Cruaud C, Pellet J, Proux F, Hennion M, Engelen S, Lemainque A, Audit B, Hyrien O, Le Tallec B. Genome-wide mapping of individual replication fork velocities using nanopore sequencing. Nat Commun 2022; 13:3295. [PMID: 35676270 PMCID: PMC9177527 DOI: 10.1038/s41467-022-31012-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/26/2022] [Indexed: 01/27/2023] Open
Abstract
Little is known about replication fork velocity variations along eukaryotic genomes, since reference techniques to determine fork speed either provide no sequence information or suffer from low throughput. Here we present NanoForkSpeed, a nanopore sequencing-based method to map and extract the velocity of individual forks detected as tracks of the thymidine analogue bromodeoxyuridine incorporated during a brief pulse-labelling of asynchronously growing cells. NanoForkSpeed retrieves previous Saccharomyces cerevisiae mean fork speed estimates (≈2 kb/min) in the BT1 strain exhibiting highly efficient bromodeoxyuridine incorporation and wild-type growth, and precisely quantifies speed changes in cells with altered replisome progression or exposed to hydroxyurea. The positioning of >125,000 fork velocities provides a genome-wide map of fork progression based on individual fork rates, showing a uniform fork speed across yeast chromosomes except for a marked slowdown at known pausing sites.
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Affiliation(s)
- Bertrand Theulot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France
- Sorbonne Université, Collège Doctoral, F-75005, Paris, France
| | - Laurent Lacroix
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France.
| | - Jean-Michel Arbona
- Laboratoire de Biologie et Modélisation de la Cellule, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, INSERM, U1293, Université Claude Bernard Lyon 1, 46 allée d'Italie, F-69364, Lyon, France
| | - Gael A Millot
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, F-75015, Paris, France
| | - Etienne Jean
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France
| | - Corinne Cruaud
- Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, Evry, France
| | - Jade Pellet
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France
| | - Florence Proux
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France
| | - Magali Hennion
- Université Paris Cité, Epigenetics and Cell Fate, UMR7216, CNRS, Paris, 75013, France
| | - Stefan Engelen
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ. Evry, Université Paris-Saclay, 91057, Evry, France
| | - Arnaud Lemainque
- Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, Evry, France
| | - Benjamin Audit
- ENSL, CNRS, Laboratoire de physique, F-69342, Lyon, France
| | - Olivier Hyrien
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France.
| | - Benoît Le Tallec
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, F-75005, Paris, France.
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14
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Radchenko EA, Aksenova AY, Volkov KV, Shishkin AA, Pavlov YI, Mirkin SM. Partners in crime: Tbf1 and Vid22 promote expansions of long human telomeric repeats at an interstitial chromosome position in yeast. PNAS NEXUS 2022; 1:pgac080. [PMID: 35832866 PMCID: PMC9272169 DOI: 10.1093/pnasnexus/pgac080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/01/2022] [Indexed: 02/05/2023]
Abstract
In humans, telomeric repeats (TTAGGG)n are known to be present at internal chromosomal sites. These interstitial telomeric sequences (ITSs) are an important source of genomic instability, including repeat length polymorphism, but the molecular mechanisms responsible for this instability remain to be understood. Here, we studied the mechanisms responsible for expansions of human telomeric (Htel) repeats that were artificially inserted inside a yeast chromosome. We found that Htel repeats in an interstitial chromosome position are prone to expansions. The propensity of Htel repeats to expand depends on the presence of a complex of two yeast proteins: Tbf1 and Vid22. These two proteins are physically bound to an interstitial Htel repeat, and together they slow replication fork progression through it. We propose that slow progression of the replication fork through the protein complex formed by the Tbf1 and Vid22 partners at the Htel repeat cause DNA strand slippage, ultimately resulting in repeat expansions.
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Affiliation(s)
| | | | - Kirill V Volkov
- Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg, 199034, Russia
| | | | - Youri I Pavlov
- Eppley Institute for Research In Cancer and Allied Diseases, Omaha, NE 68198, USA
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15
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Gillespie PJ, Blow JJ. DDK: The Outsourced Kinase of Chromosome Maintenance. BIOLOGY 2022; 11:biology11060877. [PMID: 35741398 PMCID: PMC9220011 DOI: 10.3390/biology11060877] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Abstract
The maintenance of genomic stability during the mitotic cell-cycle not only demands that the DNA is duplicated and repaired with high fidelity, but that following DNA replication the chromatin composition is perpetuated and that the duplicated chromatids remain tethered until their anaphase segregation. The coordination of these processes during S phase is achieved by both cyclin-dependent kinase, CDK, and Dbf4-dependent kinase, DDK. CDK orchestrates the activation of DDK at the G1-to-S transition, acting as the ‘global’ regulator of S phase and cell-cycle progression, whilst ‘local’ control of the initiation of DNA replication and repair and their coordination with the re-formation of local chromatin environments and the establishment of chromatid cohesion are delegated to DDK. Here, we discuss the regulation and the multiple roles of DDK in ensuring chromosome maintenance. Regulation of replication initiation by DDK has long been known to involve phosphorylation of MCM2-7 subunits, but more recent results have indicated that Treslin:MTBP might also be important substrates. Molecular mechanisms by which DDK regulates replisome stability and replicated chromatid cohesion are less well understood, though important new insights have been reported recently. We discuss how the ‘outsourcing’ of activities required for chromosome maintenance to DDK allows CDK to maintain outright control of S phase progression and the cell-cycle phase transitions whilst permitting ongoing chromatin replication and cohesion establishment to be completed and achieved faithfully.
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16
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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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17
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Grabarczyk DB. The Fork Protection Complex: A Regulatory Hub at the Head of the Replisome. Subcell Biochem 2022; 99:83-107. [PMID: 36151374 DOI: 10.1007/978-3-031-00793-4_3] [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: 06/16/2023]
Abstract
As well as accurately duplicating DNA, the eukaryotic replisome performs a variety of other crucial tasks to maintain genomic stability. For example, organizational elements, like cohesin, must be transferred from the front of the fork to the new strands, and when there is replication stress, forks need to be protected and checkpoint signalling activated. The Tof1-Csm3 (or Timeless-Tipin in humans) Fork Protection Complex (FPC) ensures efficient replisome progression and is required for a range of replication-associated activities. Recent studies have begun to reveal the structure of this complex, and how it functions within the replisome to perform its diverse roles. The core of the FPC acts as a DNA grip on the front of the replisome to regulate fork progression. Other flexibly linked domains and motifs mediate interactions with proteins and specific DNA structures, enabling the FPC to act as a hub at the head of the replication fork.
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Affiliation(s)
- Daniel B Grabarczyk
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, Würzburg, Germany.
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria.
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18
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Jones ML, Baris Y, Taylor MRG, Yeeles JTP. Structure of a human replisome shows the organisation and interactions of a DNA replication machine. EMBO J 2021; 40:e108819. [PMID: 34694004 PMCID: PMC8634136 DOI: 10.15252/embj.2021108819] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 02/01/2023] Open
Abstract
The human replisome is an elaborate arrangement of molecular machines responsible for accurate chromosome replication. At its heart is the CDC45-MCM-GINS (CMG) helicase, which, in addition to unwinding the parental DNA duplex, arranges many proteins including the leading-strand polymerase Pol ε, together with TIMELESS-TIPIN, CLASPIN and AND-1 that have key and varied roles in maintaining smooth replisome progression. How these proteins are coordinated in the human replisome is poorly understood. We have determined a 3.2 Å cryo-EM structure of a human replisome comprising CMG, Pol ε, TIMELESS-TIPIN, CLASPIN and AND-1 bound to replication fork DNA. The structure permits a detailed understanding of how AND-1, TIMELESS-TIPIN and Pol ε engage CMG, reveals how CLASPIN binds to multiple replisome components and identifies the position of the Pol ε catalytic domain. Furthermore, the intricate network of contacts contributed by MCM subunits and TIMELESS-TIPIN with replication fork DNA suggests a mechanism for strand separation.
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19
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Kemiha S, Poli J, Lin YL, Lengronne A, Pasero P. Toxic R-loops: Cause or consequence of replication stress? DNA Repair (Amst) 2021; 107:103199. [PMID: 34399314 DOI: 10.1016/j.dnarep.2021.103199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 01/08/2023]
Abstract
Transcription-replication conflicts (TRCs) represent a potential source of endogenous replication stress (RS) and genomic instability in eukaryotic cells but the mechanisms that underlie this instability remain poorly understood. Part of the problem could come from non-B DNA structures called R-loops, which are formed of a RNA:DNA hybrid and a displaced ssDNA loop. In this review, we discuss different scenarios in which R-loops directly or indirectly interfere with DNA replication. We also present other types of TRCs that may not depend on R-loops to impede fork progression. Finally, we discuss alternative models in which toxic RNA:DNA hybrids form at stalled forks as a consequence - but not a cause - of replication stress and interfere with replication resumption.
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Affiliation(s)
- Samira Kemiha
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Jérôme Poli
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Yea-Lih Lin
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France.
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20
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Kumar C, Batra S, Griffith JD, Remus D. The interplay of RNA:DNA hybrid structure and G-quadruplexes determines the outcome of R-loop-replisome collisions. eLife 2021; 10:72286. [PMID: 34494544 PMCID: PMC8479836 DOI: 10.7554/elife.72286] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 09/07/2021] [Indexed: 12/11/2022] Open
Abstract
R-loops are a major source of genome instability associated with transcription-induced replication stress. However, how R-loops inherently impact replication fork progression is not understood. Here, we characterize R-loop-replisome collisions using a fully reconstituted eukaryotic DNA replication system. We find that RNA:DNA hybrids and G-quadruplexes at both co-directional and head-on R-loops can impact fork progression by inducing fork stalling, uncoupling of leading strand synthesis from replisome progression, and nascent strand gaps. RNase H1 and Pif1 suppress replication defects by resolving RNA:DNA hybrids and G-quadruplexes, respectively. We also identify an intrinsic capacity of replisomes to maintain fork progression at certain R-loops by unwinding RNA:DNA hybrids, repriming leading strand synthesis downstream of G-quadruplexes, or utilizing R-loop transcripts to prime leading strand restart during co-directional R-loop-replisome collisions. Collectively, the data demonstrates that the outcome of R-loop-replisome collisions is modulated by R-loop structure, providing a mechanistic basis for the distinction of deleterious from non-deleterious R-loops.
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Affiliation(s)
- Charanya Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Sahil Batra
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center and Departments of Microbiology and Immunology, and Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
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21
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McClure AW, Diffley JF. Rad53 checkpoint kinase regulation of DNA replication fork rate via Mrc1 phosphorylation. eLife 2021; 10:69726. [PMID: 34387546 PMCID: PMC8387023 DOI: 10.7554/elife.69726] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 08/12/2021] [Indexed: 12/18/2022] Open
Abstract
The Rad53 DNA checkpoint protein kinase plays multiple roles in the budding yeast cell response to DNA replication stress. Key amongst these is its enigmatic role in safeguarding DNA replication forks. Using DNA replication reactions reconstituted with purified proteins, we show Rad53 phosphorylation of Sld3/7 or Dbf4-dependent kinase blocks replication initiation whilst phosphorylation of Mrc1 or Mcm10 slows elongation. Mrc1 phosphorylation is necessary and sufficient to slow replication forks in complete reactions; Mcm10 phosphorylation can also slow replication forks, but only in the absence of unphosphorylated Mrc1. Mrc1 stimulates the unwinding rate of the replicative helicase, CMG, and Rad53 phosphorylation of Mrc1 prevents this. We show that a phosphorylation-mimicking Mrc1 mutant cannot stimulate replication in vitro and partially rescues the sensitivity of a rad53 null mutant to genotoxic stress in vivo. Our results show that Rad53 protects replication forks in part by antagonising Mrc1 stimulation of CMG unwinding.
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Affiliation(s)
- Allison W McClure
- Chromosome Replication Laboratory, The Francis Crick Institute, London, United Kingdom
| | - John Fx Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, London, United Kingdom
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22
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Shyian M, Shore D. Approaching Protein Barriers: Emerging Mechanisms of Replication Pausing in Eukaryotes. Front Cell Dev Biol 2021; 9:672510. [PMID: 34124054 PMCID: PMC8194067 DOI: 10.3389/fcell.2021.672510] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/03/2021] [Indexed: 11/13/2022] Open
Abstract
During nuclear DNA replication multiprotein replisome machines have to jointly traverse and duplicate the total length of each chromosome during each cell cycle. At certain genomic locations replisomes encounter tight DNA-protein complexes and slow down. This fork pausing is an active process involving recognition of a protein barrier by the approaching replisome via an evolutionarily conserved Fork Pausing/Protection Complex (FPC). Action of the FPC protects forks from collapse at both programmed and accidental protein barriers, thus promoting genome integrity. In addition, FPC stimulates the DNA replication checkpoint and regulates topological transitions near the replication fork. Eukaryotic cells have been proposed to employ physiological programmed fork pausing for various purposes, such as maintaining copy number at repetitive loci, precluding replication-transcription encounters, regulating kinetochore assembly, or controlling gene conversion events during mating-type switching. Here we review the growing number of approaches used to study replication pausing in vivo and in vitro as well as the characterization of additional factors recently reported to modulate fork pausing in different systems. Specifically, we focus on the positive role of topoisomerases in fork pausing. We describe a model where replisome progression is inherently cautious, which ensures general preservation of fork stability and genome integrity but can also carry out specialized functions at certain loci. Furthermore, we highlight classical and novel outstanding questions in the field and propose venues for addressing them. Given how little is known about replisome pausing at protein barriers in human cells more studies are required to address how conserved these mechanisms are.
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Affiliation(s)
- Maksym Shyian
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - David Shore
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
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23
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Cook D, Long S, Stanton J, Cusick P, Lawrimore C, Yeh E, Grant S, Bloom K. Behavior of dicentric chromosomes in budding yeast. PLoS Genet 2021; 17:e1009442. [PMID: 33735169 PMCID: PMC8009378 DOI: 10.1371/journal.pgen.1009442] [Citation(s) in RCA: 9] [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: 04/30/2020] [Revised: 03/30/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022] Open
Abstract
DNA double-strand breaks arise in vivo when a dicentric chromosome (two centromeres on one chromosome) goes through mitosis with the two centromeres attached to opposite spindle pole bodies. Repair of the DSBs generates phenotypic diversity due to the range of monocentric derivative chromosomes that arise. To explore whether DSBs may be differentially repaired as a function of their spatial position in the chromosome, we have examined the structure of monocentric derivative chromosomes from cells containing a suite of dicentric chromosomes in which the distance between the two centromeres ranges from 6.5 kb to 57.7 kb. Two major classes of repair products, homology-based (homologous recombination (HR) and single-strand annealing (SSA)) and end-joining (non-homologous (NHEJ) and micro-homology mediated (MMEJ)) were identified. The distribution of repair products varies as a function of distance between the two centromeres. Genetic dependencies on double strand break repair (Rad52), DNA ligase (Lif1), and S phase checkpoint (Mrc1) are indicative of distinct repair pathway choices for DNA breaks in the pericentromeric chromatin versus the arms. A challenge in chromosome biology is to integrate the linear code with spatial organization and chromosome dynamics within the nucleus. The major sub-division of function in the nucleus is the nucleolus, the site of ribosomal RNA synthesis. We report that the pericentromere DNA surrounding the centromere is another region of confined biochemistry. We have found that chromosome breaks between two centromeres that both lie within the pericentromeric region of the chromosomes are repaired via pathways that do not rely on sequence homology (MMEJ or NHEJ). Chromosome breaks in dicentric chromosomes whose centromeres are separated by > 20 kb are repaired via pathways that rely mainly on sequence homology (HR, SSA). The repair of breaks in the pericentromere versus breaks in the arms are differentially dependent on Rad52, Lif1, and Mrc1, further indicative of spatial control over DNA repair pathways.
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Affiliation(s)
- Diana Cook
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sarah Long
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - John Stanton
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Patrick Cusick
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Colleen Lawrimore
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Elaine Yeh
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sarah Grant
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kerry Bloom
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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24
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Li H, Zheng F, O'Donnell M. Water skating: How polymerase sliding clamps move on DNA. FEBS J 2021; 288:7256-7262. [PMID: 33523561 DOI: 10.1111/febs.15740] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/19/2021] [Accepted: 01/24/2021] [Indexed: 11/30/2022]
Abstract
Polymerase sliding clamps are ring-shaped proteins that encircle duplex DNA and hold polymerases to DNA for high processivity during synthesis. The crystal structure of clamp-DNA complex reveals that the DNA is highly tilted through the clamp with extensive interaction with the clamp inner surface. In contrast to the tilted clamp-DNA interaction without DNA polymerases, recent structures of replicative polymerases of bacteria, eukaryotes, and archaea that are bound to the clamp and DNA show that the polymerase positions DNA straight through the clamp without direct protein-DNA contacts. Instead, the clamp-to-DNA interaction is mediated by one or two layers of water. Hence, clamps 'water skate' on DNA during function with replicative polymerases from all domains of life, providing a nearly frictionless bearing for fast and processive DNA synthesis.
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Affiliation(s)
- Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Mike O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA.,HHMI, The Rockefeller University, New York, NY, USA
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25
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Westhorpe R, Keszthelyi A, Minchell NE, Jones D, Baxter J. Separable functions of Tof1/Timeless in intra-S-checkpoint signalling, replisome stability and DNA topological stress. Nucleic Acids Res 2020; 48:12169-12187. [PMID: 33166393 PMCID: PMC7708041 DOI: 10.1093/nar/gkaa963] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022] Open
Abstract
The highly conserved Tof1/Timeless proteins minimise replication stress and promote normal DNA replication. They are required to mediate the DNA replication checkpoint (DRC), the stable pausing of forks at protein fork blocks, the coupling of DNA helicase and polymerase functions during replication stress (RS) and the preferential resolution of DNA topological stress ahead of the fork. Here we demonstrate that the roles of the Saccharomyces cerevisiae Timeless protein Tof1 in DRC signalling and resolution of DNA topological stress require distinct N and C terminal regions of the protein, whereas the other functions of Tof1 are closely linked to the stable interaction between Tof1 and its constitutive binding partner Csm3/Tipin. By separating the role of Tof1 in DRC from fork stabilisation and coupling, we show that Tof1 has distinct activities in checkpoint activation and replisome stability to ensure the viable completion of DNA replication following replication stress.
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Affiliation(s)
- Rose Westhorpe
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Andrea Keszthelyi
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Nicola E Minchell
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - David Jones
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Jonathan Baxter
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
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26
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Wang L, Song K, Qu Y, Chang Y, Li Z, Dong C, Liu M, Brennan JD, Li Y. Engineering Micrometer-Sized DNA Tracks for High-Speed DNA Synthesis and Biosensing. Angew Chem Int Ed Engl 2020; 59:22947-22951. [PMID: 33007137 DOI: 10.1002/anie.202010693] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/22/2020] [Indexed: 01/07/2023]
Abstract
φ29 DNA polymerase (Polφ29) is capable of synthesizing long-chain single-stranded (ss) DNA molecules by copying the sequence of a small ss circular DNA template (ssCDT) in a process known as rolling circle amplification (RCA). The use of a ssCDT in RCA, however, comes with a key drawback: the rate of DNA synthesis is significantly reduced. We hypothesize that this issue can be overcome using a very long linear ssDNA template with a repeating sequence. To test this idea, we engineered a DNA assembly, which we denote "micrometer-sized DNA track" (μDT). This μDT, with an average length of ≈13.5 μm, is made of a long chain DNA with a primer-binding domain at its 3' end and ≈1000 repeating sequence units at its 5' end, each carrying a DNA anchor. We find that Polφ29 copies μDT at a speed ≈5-time faster than it does a related ssCDT. We use this to design a simple all-in-one printed paper device for rapid and sensitive detection of microRNA let-7. This paper sensor is capable of detecting 1 pM let-7a in 10 minutes.
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Affiliation(s)
- Liying Wang
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education), Dalian University of Technology, Dalian, 116024, China
| | - Kaiyun Song
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education), Dalian University of Technology, Dalian, 116024, China
| | - Yuanyuan Qu
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education), Dalian University of Technology, Dalian, 116024, China
| | - Yangyang Chang
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education), Dalian University of Technology, Dalian, 116024, China
| | - Zhongping Li
- Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China
| | - Chuan Dong
- Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China
| | - Meng Liu
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education), Dalian University of Technology, Dalian, 116024, China
| | - John D Brennan
- Biointerfaces Institute, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S4O3, Canada
| | - Yingfu Li
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S4K1, Canada
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27
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Wang L, Song K, Qu Y, Chang Y, Li Z, Dong C, Liu M, Brennan JD, Li Y. Engineering Micrometer‐Sized DNA Tracks for High‐Speed DNA Synthesis and Biosensing. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Liying Wang
- School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education) Dalian University of Technology Dalian 116024 China
| | - Kaiyun Song
- School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education) Dalian University of Technology Dalian 116024 China
| | - Yuanyuan Qu
- School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education) Dalian University of Technology Dalian 116024 China
| | - Yangyang Chang
- School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education) Dalian University of Technology Dalian 116024 China
| | - Zhongping Li
- Institute of Environmental Science Shanxi University Taiyuan 030006 China
| | - Chuan Dong
- Institute of Environmental Science Shanxi University Taiyuan 030006 China
| | - Meng Liu
- School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering, (Ministry of Education) Dalian University of Technology Dalian 116024 China
| | - John D. Brennan
- Biointerfaces Institute McMaster University 1280 Main Street West Hamilton Ontario L8S4O3 Canada
| | - Yingfu Li
- Department of Biochemistry and Biomedical Sciences McMaster University 1280 Main Street West Hamilton Ontario L8S4K1 Canada
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28
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Stokes K, Winczura A, Song B, Piccoli GD, Grabarczyk DB. Ctf18-RFC and DNA Pol ϵ form a stable leading strand polymerase/clamp loader complex required for normal and perturbed DNA replication. Nucleic Acids Res 2020; 48:8128-8145. [PMID: 32585006 PMCID: PMC7641331 DOI: 10.1093/nar/gkaa541] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/05/2020] [Accepted: 06/16/2020] [Indexed: 12/28/2022] Open
Abstract
The eukaryotic replisome must faithfully replicate DNA and cope with replication fork blocks and stalling, while simultaneously promoting sister chromatid cohesion. Ctf18-RFC is an alternative PCNA loader that links all these processes together by an unknown mechanism. Here, we use integrative structural biology combined with yeast genetics and biochemistry to highlight the specific functions that Ctf18-RFC plays within the leading strand machinery via an interaction with the catalytic domain of DNA Pol ϵ. We show that a large and unusually flexible interface enables this interaction to occur constitutively throughout the cell cycle and regardless of whether forks are replicating or stalled. We reveal that, by being anchored to the leading strand polymerase, Ctf18-RFC can rapidly signal fork stalling to activate the S phase checkpoint. Moreover, we demonstrate that, independently of checkpoint signaling or chromosome cohesion, Ctf18-RFC functions in parallel to Chl1 and Mrc1 to protect replication forks and cell viability.
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Affiliation(s)
- Katy Stokes
- University of Warwick, Warwick Medical School, Coventry, UK
| | | | - Boyuan Song
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, Josef-Schneider-Str. 2, Würzburg 97080, Germany.,Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, Würzburg 97074, Germany
| | | | - Daniel B Grabarczyk
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, Josef-Schneider-Str. 2, Würzburg 97080, Germany
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29
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Le TT, Gao X, Park SH, Lee J, Inman JT, Lee JH, Killian JL, Badman RP, Berger JM, Wang MD. Synergistic Coordination of Chromatin Torsional Mechanics and Topoisomerase Activity. Cell 2020; 179:619-631.e15. [PMID: 31626768 PMCID: PMC6899335 DOI: 10.1016/j.cell.2019.09.034] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/16/2019] [Accepted: 09/24/2019] [Indexed: 12/23/2022]
Abstract
DNA replication in eukaryotes generates DNA supercoiling, which may intertwine (braid) daughter chromatin fibers to form precatenanes, posing topological challenges during chromosome segregation. The mechanisms that limit precatenane formation remain unclear. By making direct torque measurements, we demonstrate that the intrinsic mechanical properties of chromatin play a fundamental role in dictating precatenane formation and regulating chromatin topology. Whereas a single chromatin fiber is torsionally soft, a braided fiber is torsionally stiff, indicating that supercoiling on chromatin substrates is preferentially directed in front of the fork during replication. We further show that topoisomerase II relaxation displays a strong preference for a single chromatin fiber over a braided fiber. These results suggest a synergistic coordination-the mechanical properties of chromatin inherently suppress precatenane formation during replication elongation by driving DNA supercoiling ahead of the fork, where supercoiling is more efficiently removed by topoisomerase II. VIDEO ABSTRACT.
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Affiliation(s)
- Tung T Le
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Xiang Gao
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Seong Ha Park
- Biophysics Program, Cornell University, Ithaca, NY 14853, USA
| | - Jaeyoon Lee
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - James T Inman
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Joyce H Lee
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica L Killian
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Ryan P Badman
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michelle D Wang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA.
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30
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Ahmed Ezzat H, Price C. Characterisation of unessential genes required for survival under conditions of DNA stress. J Genet Eng Biotechnol 2020; 18:14. [PMID: 32372157 PMCID: PMC7201005 DOI: 10.1186/s43141-020-00025-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/11/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Genomic instability is a hallmark of cancer. Cancer progression depends on the development and amplification of mutations that alter the cellular response to threats to the genome. This can lead to DNA replication stress and the potential loss of genetic integrity of the newly formed cells. This study utilised fission yeast to map the interactions occurring in some of the most crucial pathways in both DNA replication and checkpoint monitoring involving Rad4, the Schizosaccharomyces pombe (S. pombe) TopBP1 homologue. We have modelled conditions of replication stress in the genetically tractable fission yeast, S. pombe using the hypomorphic rad4-116 allele. Synthetic genetic analysis was used to identify processes required for cell survival under conditions of DNA replication stress. With the aim of mapping the genetic interactions of rad4 and its mutant allele, rad4-116, several genes that could have an interaction with rad4 during replication stress have emerged as attractive. RESULTS Interactions with genes involved in chromatin remodelling, such as hip1, and replication fork stalling resolution, such as mrc1, swi1 and swi3 were explored and confirmed. The interactions of Rad4 with each of the genes provided separate and distinct tumour formation pathways, as evident in the synthetically lethal interactions. Even within the same complex, rad4-116 double mutants behaved differently proving that Rad4 interacts at different levels and functions with the same proteins. CONCLUSION Results from this study provide a novel view of the rad4 interactions, the association of Rad4 with the replisome. The study also provides the groundwork on a theoretical and practical level for the exploration and separation of interactions of TopBP1 with the histone chaperone family and the replisome.
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Affiliation(s)
- Hassan Ahmed Ezzat
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK.
| | - Clive Price
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK
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31
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Baretić D, Jenkyn-Bedford M, Aria V, Cannone G, Skehel M, Yeeles JTP. Cryo-EM Structure of the Fork Protection Complex Bound to CMG at a Replication Fork. Mol Cell 2020; 78:926-940.e13. [PMID: 32369734 PMCID: PMC7276988 DOI: 10.1016/j.molcel.2020.04.012] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
The eukaryotic replisome, organized around the Cdc45-MCM-GINS (CMG) helicase, orchestrates chromosome replication. Multiple factors associate directly with CMG, including Ctf4 and the heterotrimeric fork protection complex (Csm3/Tof1 and Mrc1), which has important roles including aiding normal replication rates and stabilizing stalled forks. How these proteins interface with CMG to execute these functions is poorly understood. Here we present 3 to 3.5 Å resolution electron cryomicroscopy (cryo-EM) structures comprising CMG, Ctf4, and the fork protection complex at a replication fork. The structures provide high-resolution views of CMG-DNA interactions, revealing a mechanism for strand separation, and show Csm3/Tof1 “grip” duplex DNA ahead of CMG via a network of interactions important for efficient replication fork pausing. Although Mrc1 was not resolved in our structures, we determine its topology in the replisome by cross-linking mass spectrometry. Collectively, our work reveals how four highly conserved replisome components collaborate with CMG to facilitate replisome progression and maintain genome stability. Cryo-EM structure of Csm3/Tof1 and Ctf4 bound to the eukaryotic CMG helicase Csm3/Tof1 are positioned at the front of the replisome where they grip duplex DNA High-resolution views of CMG-DNA contacts suggest a mechanism for strand separation Mrc1 binds across one side of CMG contacting the front and back of the replisome
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Affiliation(s)
- Domagoj Baretić
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | | | - Valentina Aria
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Giuseppe Cannone
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Mark Skehel
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Joseph T P Yeeles
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK.
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32
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Onaka AT, Su J, Katahira Y, Tang C, Zafar F, Aoki K, Kagawa W, Niki H, Iwasaki H, Nakagawa T. DNA replication machinery prevents Rad52-dependent single-strand annealing that leads to gross chromosomal rearrangements at centromeres. Commun Biol 2020; 3:202. [PMID: 32355220 PMCID: PMC7193609 DOI: 10.1038/s42003-020-0934-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 04/09/2020] [Indexed: 12/27/2022] Open
Abstract
Homologous recombination between repetitive sequences can lead to gross chromosomal rearrangements (GCRs). At fission yeast centromeres, Rad51-dependent conservative recombination predominantly occurs between inverted repeats, thereby suppressing formation of isochromosomes whose arms are mirror images. However, it is unclear how GCRs occur in the absence of Rad51 and how GCRs are prevented at centromeres. Here, we show that homology-mediated GCRs occur through Rad52-dependent single-strand annealing (SSA). The rad52-R45K mutation, which impairs SSA activity of Rad52 protein, dramatically reduces isochromosome formation in rad51 deletion cells. A ring-like complex Msh2-Msh3 and a structure-specific endonuclease Mus81 function in the Rad52-dependent GCR pathway. Remarkably, mutations in replication fork components, including DNA polymerase α and Swi1/Tof1/Timeless, change the balance between Rad51-dependent recombination and Rad52-dependent SSA at centromeres, increasing Rad52-dependent SSA that forms isochromosomes. Our results uncover a role of DNA replication machinery in the recombination pathway choice that prevents Rad52-dependent GCRs at centromeres.
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Affiliation(s)
- Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Chitose Laboratory Corporation, 2-13-3 Nogawa-honcho, Miyamae-ku, Kawasaki, Kanagawa, 216-0041, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Yasuhiro Katahira
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Department of Immunoregulation, Institute of Medical Science, Tokyo Medical University, 6-1-1 Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Crystal Tang
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Keita Aoki
- Microbial Physiology Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Wataru Kagawa
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo, 191-8506, Japan
| | - Hironori Niki
- Microbial Physiology Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
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33
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Feu S, Unzueta F, Llopis A, Semple JI, Ercilla A, Guaita-Esteruelas S, Jaumot M, Freire R, Agell N. OZF is a Claspin-interacting protein essential to maintain the replication fork progression rate under replication stress. FASEB J 2020; 34:6907-6919. [PMID: 32267586 DOI: 10.1096/fj.201901926r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 03/10/2020] [Accepted: 03/16/2020] [Indexed: 12/12/2022]
Abstract
DNA replication is essential for cell proliferation and is one of the cell cycle stages where DNA is more vulnerable. Replication stress is a prominent property of tumor cells and an emerging target for cancer therapy. Although it is not directly involved in nucleotide incorporation, Claspin is a protein with relevant functions in DNA replication. It harbors a DNA-binding domain that interacts preferentially with branched or forked DNA molecules. It also acts as a platform for the interaction of proteins related to DNA damage checkpoint activation, DNA repair, DNA replication origin firing, and fork progression. In order to find new proteins potentially involved in the regulation of DNA replication, we performed a two-hybrid screen to discover new Claspin-binding proteins. This system allowed us to identify the zinc-finger protein OZF (ZNF146) as a new Claspin-interacting protein. OZF is also present at replication forks and co-immunoprecipitates not only with Claspin but also with other replisome components. Interestingly, OZF depletion does not affect DNA replication in a normal cell cycle, but its depletion induces a reduction in the fork progression rate under replication stress conditions. Our results suggest that OZF is a Claspin-binding protein with a specific function in fork progression under replication stress.
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Affiliation(s)
- Sonia Feu
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Fernando Unzueta
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Alba Llopis
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | | | - Amaia Ercilla
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Sandra Guaita-Esteruelas
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Montserrat Jaumot
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, FIISC, La Laguna, Spain.,Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain.,Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, Spain
| | - Neus Agell
- Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
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34
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Appanah R, Lones EC, Aiello U, Libri D, De Piccoli G. Sen1 Is Recruited to Replication Forks via Ctf4 and Mrc1 and Promotes Genome Stability. Cell Rep 2020; 30:2094-2105.e9. [PMID: 32075754 PMCID: PMC7034062 DOI: 10.1016/j.celrep.2020.01.087] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 09/06/2019] [Accepted: 01/24/2020] [Indexed: 01/21/2023] Open
Abstract
DNA replication and RNA transcription compete for the same substrate during S phase. Cells have evolved several mechanisms to minimize such conflicts. Here, we identify the mechanism by which the transcription termination helicase Sen1 associates with replisomes. We show that the N terminus of Sen1 is both sufficient and necessary for replisome association and that it binds to the replisome via the components Ctf4 and Mrc1. We generated a separation of function mutant, sen1-3, which abolishes replisome binding without affecting transcription termination. We observe that the sen1-3 mutants show increased genome instability and recombination levels. Moreover, sen1-3 is synthetically defective with mutations in genes involved in RNA metabolism and the S phase checkpoint. RNH1 overexpression suppresses defects in the former, but not the latter. These findings illustrate how Sen1 plays a key function at replication forks during DNA replication to promote fork progression and chromosome stability.
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Affiliation(s)
- Rowin Appanah
- Warwick Medical School, University of Warwick, CV4 7AL Coventry, UK
| | | | - Umberto Aiello
- Institut Jacques Monod, CNRS, UMR7592, Université Paris Diderot, Paris Sorbonne Cité, Paris, France
| | - Domenico Libri
- Institut Jacques Monod, CNRS, UMR7592, Université Paris Diderot, Paris Sorbonne Cité, Paris, France
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35
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Lawrimore CJ, Bloom K. Common Features of the Pericentromere and Nucleolus. Genes (Basel) 2019; 10:E1029. [PMID: 31835574 PMCID: PMC6947172 DOI: 10.3390/genes10121029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/05/2019] [Accepted: 12/07/2019] [Indexed: 12/20/2022] Open
Abstract
Both the pericentromere and the nucleolus have unique characteristics that distinguish them amongst the rest of genome. Looping of pericentromeric DNA, due to structural maintenance of chromosome (SMC) proteins condensin and cohesin, drives its ability to maintain tension during metaphase. Similar loops are formed via condensin and cohesin in nucleolar ribosomal DNA (rDNA). Condensin and cohesin are also concentrated in transfer RNA (tRNA) genes, genes which may be located within the pericentromere as well as tethered to the nucleolus. Replication fork stalling, as well as downstream consequences such as genomic recombination, are characteristic of both the pericentromere and rDNA. Furthermore, emerging evidence suggests that the pericentromere may function as a liquid-liquid phase separated domain, similar to the nucleolus. We therefore propose that the pericentromere and nucleolus, in part due to their enrichment of SMC proteins and others, contain similar domains that drive important cellular activities such as segregation, stability, and repair.
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Affiliation(s)
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA;
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36
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Shyian M, Albert B, Zupan AM, Ivanitsa V, Charbonnet G, Dilg D, Shore D. Fork pausing complex engages topoisomerases at the replisome. Genes Dev 2019; 34:87-98. [PMID: 31805522 PMCID: PMC6938670 DOI: 10.1101/gad.331868.119] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/07/2019] [Indexed: 12/22/2022]
Abstract
In this study, Shyian et al. set out to address mechanistically how the evolutionarily conserved fork pausing complex acts at proteinaceous replication fork barriers (RFBs) to promote fork passage and genome stability. Using several molecular and cell-based assays, the authors propose that forks pause at proteinaceous RFBs through a “sTOP” mechanism (“slowing down with topoisomerases I–II”), which also contributes to protecting cells from topoisomerase-blocking agents. Replication forks temporarily or terminally pause at hundreds of hard-to-replicate regions around the genome. A conserved pair of budding yeast replisome components Tof1–Csm3 (fission yeast Swi1–Swi3 and human TIMELESS–TIPIN) act as a “molecular brake” and promote fork slowdown at proteinaceous replication fork barriers (RFBs), while the accessory helicase Rrm3 assists the replisome in removing protein obstacles. Here we show that the Tof1–Csm3 complex promotes fork pausing independently of Rrm3 helicase by recruiting topoisomerase I (Top1) to the replisome. Topoisomerase II (Top2) partially compensates for the pausing decrease in cells when Top1 is lost from the replisome. The C terminus of Tof1 is specifically required for Top1 recruitment to the replisome and fork pausing but not for DNA replication checkpoint (DRC) activation. We propose that forks pause at proteinaceous RFBs through a “sTOP” mechanism (“slowing down with topoisomerases I–II”), which we show also contributes to protecting cells from topoisomerase-blocking agents.
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Affiliation(s)
- Maksym Shyian
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - Benjamin Albert
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - Andreja Moset Zupan
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - Vitalii Ivanitsa
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - Gabriel Charbonnet
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - Daniel Dilg
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
| | - David Shore
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva 4, CH-1211, Switzerland
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37
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Lewis JS, Spenkelink LM, Schauer GD, Yurieva O, Mueller SH, Natarajan V, Kaur G, Maher C, Kay C, O'Donnell ME, van Oijen AM. Tunability of DNA Polymerase Stability during Eukaryotic DNA Replication. Mol Cell 2019; 77:17-25.e5. [PMID: 31704183 DOI: 10.1016/j.molcel.2019.10.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/25/2019] [Accepted: 10/01/2019] [Indexed: 12/29/2022]
Abstract
Structural and biochemical studies have revealed the basic principles of how the replisome duplicates genomic DNA, but little is known about its dynamics during DNA replication. We reconstitute the 34 proteins needed to form the S. cerevisiae replisome and show how changing local concentrations of the key DNA polymerases tunes the ability of the complex to efficiently recycle these proteins or to dynamically exchange them. Particularly, we demonstrate redundancy of the Pol α-primase DNA polymerase activity in replication and show that Pol α-primase and the lagging-strand Pol δ can be re-used within the replisome to support the synthesis of large numbers of Okazaki fragments. This unexpected malleability of the replisome might allow it to deal with barriers and resource challenges during replication of large genomes.
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Affiliation(s)
- Jacob S Lewis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Lisanne M Spenkelink
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Grant D Schauer
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Olga Yurieva
- Laboratory of DNA Replication, Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, Cambridge, MA 02138, USA
| | - Stefan H Mueller
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Varsha Natarajan
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Gurleen Kaur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Claire Maher
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Callum Kay
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Michael E O'Donnell
- Laboratory of DNA Replication, Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, Cambridge, MA 02138, USA.
| | - Antoine M van Oijen
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health & Medical Research Institute, Wollongong, NSW 2522, Australia.
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38
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Chen CF, Pohl TJ, Chan A, Slocum JS, Zakian VA. Saccharomyces cerevisiae Centromere RNA Is Negatively Regulated by Cbf1 and Its Unscheduled Synthesis Impacts CenH3 Binding. Genetics 2019; 213:465-479. [PMID: 31391265 PMCID: PMC6781895 DOI: 10.1534/genetics.119.302528] [Citation(s) in RCA: 9] [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: 06/20/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022] Open
Abstract
Two common features of centromeres are their transcription into noncoding centromere RNAs (cen-RNAs) and their assembly into nucleosomes that contain a centromere-specific histone H3 (cenH3). Here, we show that Saccharomyces cerevisiae cen-RNA was present in low amounts in wild-type (WT) cells, and that its appearance was tightly cell cycle-regulated, appearing and disappearing in a narrow window in S phase after centromere replication. In cells lacking Cbf1, a centromere-binding protein, cen-RNA was 5-12 times more abundant throughout the cell cycle. In WT cells, cen-RNA appearance occurred at the same time as loss of Cbf1's centromere binding, arguing that the physical presence of Cbf1 inhibits cen-RNA production. Binding of the Pif1 DNA helicase, which happens in mid-late S phase, occurred at about the same time as Cbf1 loss from the centromere, suggesting that Pif1 may facilitate this loss by its known ability to displace proteins from DNA. Cen-RNAs were more abundant in rnh1Δ cells but only in mid-late S phase. However, fork pausing at centromeres was not elevated in rnh1Δ cells but rather was due to centromere-binding proteins, including Cbf1 Strains with increased cen-RNA lost centromere plasmids at elevated rates. In cbf1Δ cells, where both the levels and the cell cycle-regulated appearance of cen-RNA were disrupted, the timing and levels of cenH3 centromere binding were perturbed. Thus, cen-RNAs are highly regulated, and disruption of this regulation correlates with changes in centromere structure and function.
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Affiliation(s)
- Chi-Fu Chen
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Thomas J Pohl
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Angela Chan
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Joshua S Slocum
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Virginia A Zakian
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
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39
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Gellon L, Kaushal S, Cebrián J, Lahiri M, Mirkin SM, Freudenreich CH. Mrc1 and Tof1 prevent fragility and instability at long CAG repeats by their fork stabilizing function. Nucleic Acids Res 2019; 47:794-805. [PMID: 30476303 PMCID: PMC6344861 DOI: 10.1093/nar/gky1195] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/13/2018] [Indexed: 12/14/2022] Open
Abstract
Fork stabilization at DNA impediments is key to maintaining replication fork integrity and preventing chromosome breaks. Mrc1 and Tof1 are two known stabilizers that travel with the replication fork. In addition to a structural role, Mrc1 has a DNA damage checkpoint function. Using a yeast model system, we analyzed the role of Mrc1 and Tof1 at expanded CAG repeats of medium and long lengths, which are known to stall replication forks and cause trinucleotide expansion diseases such as Huntington's disease and myotonic dystrophy. We demonstrate that the fork stabilizer but not the checkpoint activation function of Mrc1 is key for preventing DNA breakage and death of cells containing expanded CAG tracts. In contrast, both Mrc1 functions are important in preventing repeat length instability. Mrc1 has a general fork protector role that is evident at forks traversing both repetitive and non-repetitive DNA, though it becomes crucial at long CAG repeat lengths. In contrast, the role of Tof1 in preventing fork breakage is specific to long CAG tracts of 85 or more repeats. Our results indicate that long CAG repeats have a particular need for Tof1 and highlight the importance of fork stabilizers in maintaining fork integrity during replication of structure-forming repeats.
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Affiliation(s)
- Lionel Gellon
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Simran Kaushal
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Jorge Cebrián
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Mayurika Lahiri
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
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40
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Lawrimore J, Bloom K. The regulation of chromosome segregation via centromere loops. Crit Rev Biochem Mol Biol 2019; 54:352-370. [PMID: 31573359 PMCID: PMC6856439 DOI: 10.1080/10409238.2019.1670130] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/02/2019] [Accepted: 09/17/2019] [Indexed: 12/14/2022]
Abstract
Biophysical studies of the yeast centromere have shown that the organization of the centromeric chromatin plays a crucial role in maintaining proper tension between sister kinetochores during mitosis. While centromeric chromatin has traditionally been considered a simple spring, recent work reveals the centromere as a multifaceted, tunable shock absorber. Centromeres can differ from other regions of the genome in their heterochromatin state, supercoiling state, and enrichment of structural maintenance of chromosomes (SMC) protein complexes. Each of these differences can be utilized to alter the effective stiffness of centromeric chromatin. In budding yeast, the SMC protein complexes condensin and cohesin stiffen chromatin by forming and cross-linking chromatin loops, respectively, into a fibrous structure resembling a bottlebrush. The high density of the loops compacts chromatin while spatially isolating the tension from spindle pulling forces to a subset of the chromatin. Paradoxically, the molecular crowding of chromatin via cohesin and condensin also causes an outward/poleward force. The structure allows the centromere to act as a shock absorber that buffers the variable forces generated by dynamic spindle microtubules. Based on the distribution of SMCs from bacteria to human and the conserved distance between sister kinetochores in a wide variety of organisms (0.4 to 1 micron), we propose that the bottlebrush mechanism is the foundational principle for centromere function in eukaryotes.
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Affiliation(s)
- Josh Lawrimore
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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41
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Pohl TJ, Zakian VA. Pif1 family DNA helicases: A helpmate to RNase H? DNA Repair (Amst) 2019; 84:102633. [PMID: 31231063 DOI: 10.1016/j.dnarep.2019.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 01/21/2023]
Abstract
An R-loop is a structure that forms when an RNA transcript stays bound to the DNA strand that encodes it and leaves the complementary strand exposed as a loop of single stranded DNA. R-loops accumulate when the processing of RNA transcripts is impaired. The failure to remove these RNA-DNA hybrids can lead to replication fork stalling and genome instability. Resolution of R-loops is thought to be mediated mainly by RNase H enzymes through the removal and degradation of the RNA in the hybrid. However, DNA helicases can also dismantle R-loops by displacing the bound RNA. In particular, the Pif1 family DNA helicases have been shown to regulate R-loop formation at specific genomic loci, such as tRNA genes and centromeres. Here we review the roles of Pif1 family helicases in vivo and in vitro and discuss evidence that Pif1 family helicases act on RNA-DNA hybrids and highlight their potential roles in complementing RNase H for R-loop resolution.
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Affiliation(s)
- Thomas J Pohl
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, United States
| | - Virginia A Zakian
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, United States.
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42
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Bianco JN, Bergoglio V, Lin YL, Pillaire MJ, Schmitz AL, Gilhodes J, Lusque A, Mazières J, Lacroix-Triki M, Roumeliotis TI, Choudhary J, Moreaux J, Hoffmann JS, Tourrière H, Pasero P. Overexpression of Claspin and Timeless protects cancer cells from replication stress in a checkpoint-independent manner. Nat Commun 2019; 10:910. [PMID: 30796221 PMCID: PMC6385232 DOI: 10.1038/s41467-019-08886-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/05/2019] [Indexed: 12/31/2022] Open
Abstract
Oncogene-induced replication stress (RS) promotes cancer development but also impedes tumor growth by activating anti-cancer barriers. To determine how cancer cells adapt to RS, we have monitored the expression of different components of the ATR-CHK1 pathway in primary tumor samples. We show that unlike upstream components of the pathway, the checkpoint mediators Claspin and Timeless are overexpressed in a coordinated manner. Remarkably, reducing the levels of Claspin and Timeless in HCT116 cells to pretumoral levels impeded fork progression without affecting checkpoint signaling. These data indicate that high level of Claspin and Timeless increase RS tolerance by protecting replication forks in cancer cells. Moreover, we report that primary fibroblasts adapt to oncogene-induced RS by spontaneously overexpressing Claspin and Timeless, independently of ATR signaling. Altogether, these data indicate that enhanced levels of Claspin and Timeless represent a gain of function that protects cancer cells from of oncogene-induced RS in a checkpoint-independent manner.
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Affiliation(s)
- Julien N Bianco
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France.,Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931, Cologne, Germany
| | - Valérie Bergoglio
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL5294, University of Toulouse 3, 31037, Toulouse, France
| | - Yea-Lih Lin
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France
| | - Marie-Jeanne Pillaire
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL5294, University of Toulouse 3, 31037, Toulouse, France
| | - Anne-Lyne Schmitz
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France
| | - Julia Gilhodes
- Clinical trials Office - Biostatistics Unit, Institute Claudius Regaud, Institute Universitaire du Cancer Toulouse-Oncopole (IUCT-O), 31100, Toulouse, France
| | - Amelie Lusque
- Clinical trials Office - Biostatistics Unit, Institute Claudius Regaud, Institute Universitaire du Cancer Toulouse-Oncopole (IUCT-O), 31100, Toulouse, France
| | - Julien Mazières
- Thoracic Oncology Department, Toulouse University Hospital, University Paul Sabatier, 31062, Toulouse, France
| | | | | | | | - Jérôme Moreaux
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France
| | - Jean-Sébastien Hoffmann
- Cancer Research Center of Toulouse, INSERM U1037, CNRS ERL5294, University of Toulouse 3, 31037, Toulouse, France
| | - Hélène Tourrière
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France.
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396, Montpellier, France.
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43
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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44
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Azenha D, Lopes MC, Martins TC. Claspin: From replication stress and DNA damage responses to cancer therapy. DNA Repair (Amst) 2019; 115:203-246. [DOI: 10.1016/bs.apcsb.2018.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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45
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Two Pif1 Family DNA Helicases Cooperate in Centromere Replication and Segregation in Saccharomyces cerevisiae. Genetics 2018; 211:105-119. [PMID: 30442759 PMCID: PMC6325707 DOI: 10.1534/genetics.118.301710] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/06/2018] [Indexed: 02/07/2023] Open
Abstract
Pif1 family helicases are found in virtually all eukaryotes. Saccharomyces cerevisiae (Sc) encodes two Pif1 family helicases, ScPif1 and Rrm3 ScPif1 is multifunctional, required not only for maintenance of mitochondrial DNA but also for multiple distinct nuclear functions. Rrm3 moves with the replication fork and promotes movement of the fork through ∼1400 hard-to-replicate sites, including centromeres. Here we show that ScPif1, like Rrm3, bound robustly to yeast centromeres but only if the centromere was active. While Rrm3 binding to centromeres occurred in early to mid S phase, about the same time as centromere replication, ScPif1 binding occurred later in the cell cycle when replication of most centromeres is complete. However, the timing of Rrm3 and ScPif1 centromere binding was altered by the absence of the other helicase, such that Rrm3 centromere binding occurred later in pif1-m2 cells and ScPif1 centromere binding occurred earlier in rrm3Δ cells. As shown previously, the modest pausing of replication forks at centromeres seen in wild-type cells was increased in the absence of Rrm3 While a lack of ScPif1 did not result in increased fork pausing at centromeres, pausing was even higher in rrm3Δ pif1Δ cells than in rrm3Δ cells. Likewise, centromere function as monitored by the loss rate of a centromere plasmid was increased in rrm3Δ but not pif1Δ cells, and was even higher in rrm3Δ pif1Δ cells than in rrm3Δ cells. Thus, ScPif1 promotes centromere replication and segregation, but only in the absence of Rrm3 These data also hint at a potential post-S phase function for ScPif1 at centromeres. These studies add to the growing list of ScPif1 functions that promote chromosome stability.
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46
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Bacal J, Moriel-Carretero M, Pardo B, Barthe A, Sharma S, Chabes A, Lengronne A, Pasero P. Mrc1 and Rad9 cooperate to regulate initiation and elongation of DNA replication in response to DNA damage. EMBO J 2018; 37:e99319. [PMID: 30158111 PMCID: PMC6213276 DOI: 10.15252/embj.201899319] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/17/2018] [Accepted: 07/31/2018] [Indexed: 01/04/2023] Open
Abstract
The S-phase checkpoint maintains the integrity of the genome in response to DNA replication stress. In budding yeast, this pathway is initiated by Mec1 and is amplified through the activation of Rad53 by two checkpoint mediators: Mrc1 promotes Rad53 activation at stalled forks, and Rad9 is a general mediator of the DNA damage response. Here, we have investigated the interplay between Mrc1 and Rad9 in response to DNA damage and found that they control DNA replication through two distinct but complementary mechanisms. Mrc1 rapidly activates Rad53 at stalled forks and represses late-firing origins but is unable to maintain this repression over time. Rad9 takes over Mrc1 to maintain a continuous checkpoint signaling. Importantly, the Rad9-mediated activation of Rad53 slows down fork progression, supporting the view that the S-phase checkpoint controls both the initiation and the elongation of DNA replication in response to DNA damage. Together, these data indicate that Mrc1 and Rad9 play distinct functions that are important to ensure an optimal completion of S phase under replication stress conditions.
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Affiliation(s)
- Julien Bacal
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - María Moriel-Carretero
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Benjamin Pardo
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Antoine Barthe
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
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47
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Srivatsan A, Li BZ, Szakal B, Branzei D, Putnam CD, Kolodner RD. The Swr1 chromatin-remodeling complex prevents genome instability induced by replication fork progression defects. Nat Commun 2018; 9:3680. [PMID: 30206225 PMCID: PMC6134005 DOI: 10.1038/s41467-018-06131-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 08/09/2018] [Indexed: 01/05/2023] Open
Abstract
Genome instability is associated with tumorigenesis. Here, we identify a role for the histone Htz1, which is deposited by the Swr1 chromatin-remodeling complex (SWR-C), in preventing genome instability in the absence of the replication fork/replication checkpoint proteins Mrc1, Csm3, or Tof1. When combined with deletion of SWR1 or HTZ1, deletion of MRC1, CSM3, or TOF1 or a replication-defective mrc1 mutation causes synergistic increases in gross chromosomal rearrangement (GCR) rates, accumulation of a broad spectrum of GCRs, and hypersensitivity to replication stress. The double mutants have severe replication defects and accumulate aberrant replication intermediates. None of the individual mutations cause large increases in GCR rates; however, defects in MRC1, CSM3 or TOF1 cause activation of the DNA damage checkpoint and replication defects. We propose a model in which Htz1 deposition and retention in chromatin prevents transiently stalled replication forks that occur in mrc1, tof1, or csm3 mutants from being converted to DNA double-strand breaks that trigger genome instability.
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Affiliation(s)
- Anjana Srivatsan
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA
| | - Bin-Zhong Li
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA
| | - Barnabas Szakal
- The FIRC Institute of Molecular Oncology Foundation, Via Adamello 16, 20139, Milan, Italy
| | - Dana Branzei
- The FIRC Institute of Molecular Oncology Foundation, Via Adamello 16, 20139, Milan, Italy.,Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy
| | - Christopher D Putnam
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA.,Departments of Medicine, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA
| | - Richard D Kolodner
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA. .,Cellular and Molecular Medicine, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA. .,Moores-UCSD Cancer Center, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA. .,Institute of Genomic Medicine, University of California School of Medicine, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0669, USA.
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48
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Gurova K, Chang HW, Valieva ME, Sandlesh P, Studitsky VM. Structure and function of the histone chaperone FACT - Resolving FACTual issues. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:S1874-9399(18)30159-7. [PMID: 30055319 PMCID: PMC6349528 DOI: 10.1016/j.bbagrm.2018.07.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/12/2022]
Abstract
FAcilitates Chromatin Transcription (FACT) has been considered essential for transcription through chromatin mostly based on cell-free experiments. However, FACT inactivation in cells does not cause a significant reduction in transcription. Moreover, not all mammalian cells require FACT for viability. Here we synthesize information from different organisms to reveal the core function(s) of FACT and propose a model that reconciles the cell-free and cell-based observations. We describe FACT structure and nucleosomal interactions, and their roles in FACT-dependent transcription, replication and repair. The variable requirements for FACT among different tumor and non-tumor cells suggest that various FACT-dependent processes have significantly different levels of relative importance in different eukaryotic cells. We propose that the stability of chromatin, which might vary among different cell types, dictates these diverse requirements for FACT to support cell viability. Since tumor cells are among the most sensitive to FACT inhibition, this vulnerability could be exploited for cancer treatment.
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Affiliation(s)
- Katerina Gurova
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA.
| | - Han-Wen Chang
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Maria E Valieva
- Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Poorva Sandlesh
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Vasily M Studitsky
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA; Biology Faculty, Lomonosov Moscow State University, Moscow, Russia.
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49
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Genetic Control of Genomic Alterations Induced in Yeast by Interstitial Telomeric Sequences. Genetics 2018; 209:425-438. [PMID: 29610215 PMCID: PMC5972418 DOI: 10.1534/genetics.118.300950] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 03/27/2018] [Indexed: 11/23/2022] Open
Abstract
In many organisms, telomeric sequences can be located internally on the chromosome in addition to their usual positions at the ends of the chromosome. In humans, such interstitial telomeric sequences (ITSs) are nonrandomly associated with translocation breakpoints in tumor cells and with chromosome fragile sites (regions of the chromosome that break in response to perturbed DNA replication). We previously showed that ITSs in yeast generated several different types of instability, including terminal inversions (recombination between the ITS and the “true” chromosome telomere) and point mutations in DNA sequences adjacent to the ITS. In the current study, we examine the genetic control of these events. We show that the terminal inversions occur by the single-strand annealing pathway of DNA repair following the formation of a double-stranded DNA break within the ITS. The point mutations induced by the ITS require the error-prone DNA polymerase ζ. Unlike the terminal inversions, these events are not initiated by a double-stranded DNA break, but likely result from the error-prone repair of a single-stranded DNA gap or recruitment of DNA polymerase ζ in the absence of DNA damage.
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50
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Zhang ZX, Zhang J, Cao Q, Campbell JL, Lou H. The DNA Pol ϵ stimulatory activity of Mrc1 is modulated by phosphorylation. Cell Cycle 2017; 17:64-72. [PMID: 29157061 DOI: 10.1080/15384101.2017.1403680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
DNA replication checkpoint (Mec1-Mrc1-Rad53 in budding yeast) is an evolutionarily conserved surveillance system to ensure proper DNA replication and genome stability in all eukaryotes. Compared to its well-known function as a mediator of replication checkpoint, the exact role of Mrc1 as a component of normal replication forks remains relatively unclear. In this study, we provide in vitro biochemical evidence to support that yeast Mrc1 is able to enhance the activity of DNA polymerase ϵ (Pol ϵ), the major leading strand replicase. Mrc1 can selectively bind avidly to primer/template DNA bearing a single-stranded region, but not to double-stranded DNA (dsDNA). Mutations of the lysine residues within basic patch 1 (BP1) compromise both DNA binding and polymerase stimulatory activities. Interestingly, Mrc1-3D, a mutant mimicking phosphorylation by the Hog1/MAPK kinase during the osmotic stress response, retains DNA binding but not polymerase stimulation. The stimulatory effect is also abrogated in Mrc1 purified from cells treated with hydroxyurea (HU), which elicits replication checkpoint activation. Taken together with previous findings, these results imply that under unperturbed condition, Mrc1 has a DNA synthesis stimulatory activity, which can be eliminated via Mrc1 phosphorylation in response to replication and/or osmotic stresses.
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Affiliation(s)
- Zhong-Xin Zhang
- a Beijing Advanced Innovation Center for Food Nutrition and Human Health , State Key Laboratory of Agrobiotechnology , MOA Key Laboratory of Soil Microbiology , College of Biological Sciences , China Agricultural University , Beijing 100193 , China
| | - Jingjing Zhang
- a Beijing Advanced Innovation Center for Food Nutrition and Human Health , State Key Laboratory of Agrobiotechnology , MOA Key Laboratory of Soil Microbiology , College of Biological Sciences , China Agricultural University , Beijing 100193 , China
| | - Qinhong Cao
- a Beijing Advanced Innovation Center for Food Nutrition and Human Health , State Key Laboratory of Agrobiotechnology , MOA Key Laboratory of Soil Microbiology , College of Biological Sciences , China Agricultural University , Beijing 100193 , China
| | - Judith L Campbell
- b Braun Laboratories , California Institute of Technology , Pasadena , CA 91125 , USA
| | - Huiqiang Lou
- a Beijing Advanced Innovation Center for Food Nutrition and Human Health , State Key Laboratory of Agrobiotechnology , MOA Key Laboratory of Soil Microbiology , College of Biological Sciences , China Agricultural University , Beijing 100193 , China
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