1
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Rankin BD, Rankin S. The MCM2-7 Complex: Roles beyond DNA Unwinding. BIOLOGY 2024; 13:258. [PMID: 38666870 PMCID: PMC11048021 DOI: 10.3390/biology13040258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/07/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024]
Abstract
The MCM2-7 complex is a hexameric protein complex that serves as a DNA helicase. It unwinds the DNA double helix during DNA replication, thereby providing the single-stranded replication template. In recent years, it has become clear that the MCM2-7 complex has additional functions that extend well beyond its role in DNA replication. Through physical and functional interactions with different pathways, it impacts other nuclear events and activities, including folding of the genome, histone inheritance, chromosome segregation, DNA damage sensing and repair, and gene transcription. Collectively, the diverse roles of the MCM2-7 complex suggest it plays a critical role in maintaining genome integrity by integrating the regulation of DNA replication with other pathways in the nucleus.
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Affiliation(s)
- Brooke D. Rankin
- Cell Cycle and Cancer Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA;
- Cell Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Susannah Rankin
- Cell Cycle and Cancer Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA;
- Cell Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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2
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Nasheuer HP, Meaney AM. Starting DNA Synthesis: Initiation Processes during the Replication of Chromosomal DNA in Humans. Genes (Basel) 2024; 15:360. [PMID: 38540419 PMCID: PMC10969946 DOI: 10.3390/genes15030360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 06/14/2024] Open
Abstract
The initiation reactions of DNA synthesis are central processes during human chromosomal DNA replication. They are separated into two main processes: the initiation events at replication origins, the start of the leading strand synthesis for each replicon, and the numerous initiation events taking place during lagging strand DNA synthesis. In addition, a third mechanism is the re-initiation of DNA synthesis after replication fork stalling, which takes place when DNA lesions hinder the progression of DNA synthesis. The initiation of leading strand synthesis at replication origins is regulated at multiple levels, from the origin recognition to the assembly and activation of replicative helicase, the Cdc45-MCM2-7-GINS (CMG) complex. In addition, the multiple interactions of the CMG complex with the eukaryotic replicative DNA polymerases, DNA polymerase α-primase, DNA polymerase δ and ε, at replication forks play pivotal roles in the mechanism of the initiation reactions of leading and lagging strand DNA synthesis. These interactions are also important for the initiation of signalling at unperturbed and stalled replication forks, "replication stress" events, via ATR (ATM-Rad 3-related protein kinase). These processes are essential for the accurate transfer of the cells' genetic information to their daughters. Thus, failures and dysfunctions in these processes give rise to genome instability causing genetic diseases, including cancer. In their influential review "Hallmarks of Cancer: New Dimensions", Hanahan and Weinberg (2022) therefore call genome instability a fundamental function in the development process of cancer cells. In recent years, the understanding of the initiation processes and mechanisms of human DNA replication has made substantial progress at all levels, which will be discussed in the review.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland;
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3
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Pabba MK, Ritter C, Chagin VO, Meyer J, Celikay K, Stear JH, Loerke D, Kolobynina K, Prorok P, Schmid AK, Leonhardt H, Rohr K, Cardoso MC. Replisome loading reduces chromatin motion independent of DNA synthesis. eLife 2023; 12:RP87572. [PMID: 37906089 PMCID: PMC10617993 DOI: 10.7554/elife.87572] [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] [Indexed: 11/02/2023] Open
Abstract
Chromatin has been shown to undergo diffusional motion, which is affected during gene transcription by RNA polymerase activity. However, the relationship between chromatin mobility and other genomic processes remains unclear. Hence, we set out to label the DNA directly in a sequence unbiased manner and followed labeled chromatin dynamics in interphase human cells expressing GFP-tagged proliferating cell nuclear antigen (PCNA), a cell cycle marker and core component of the DNA replication machinery. We detected decreased chromatin mobility during the S-phase compared to G1 and G2 phases in tumor as well as normal diploid cells using automated particle tracking. To gain insight into the dynamical organization of the genome during DNA replication, we determined labeled chromatin domain sizes and analyzed their motion in replicating cells. By correlating chromatin mobility proximal to the active sites of DNA synthesis, we showed that chromatin motion was locally constrained at the sites of DNA replication. Furthermore, inhibiting DNA synthesis led to increased loading of DNA polymerases. This was accompanied by accumulation of the single-stranded DNA binding protein on the chromatin and activation of DNA helicases further restricting local chromatin motion. We, therefore, propose that it is the loading of replisomes but not their catalytic activity that reduces the dynamics of replicating chromatin segments in the S-phase as well as their accessibility and probability of interactions with other genomic regions.
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Affiliation(s)
| | - Christian Ritter
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Vadim O Chagin
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
- Institute of Cytology RASSt. PetersburgRussian Federation
| | - Janis Meyer
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Kerem Celikay
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Jeffrey H Stear
- EMBL Australia Node in Single Molecule Science, University of New South WalesSydneyAustralia
| | - Dinah Loerke
- Department of Physics & Astronomy, University of DenverDenverUnited States
| | - Ksenia Kolobynina
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
| | - Paulina Prorok
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
| | - Alice Kristin Schmid
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | | | - Karl Rohr
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - M Cristina Cardoso
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
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4
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Lim Y, Tamayo-Orrego L, Schmid E, Tarnauskaite Z, Kochenova OV, Gruar R, Muramatsu S, Lynch L, Schlie AV, Carroll PL, Chistol G, Reijns MAM, Kanemaki MT, Jackson AP, Walter JC. In silico protein interaction screening uncovers DONSON's role in replication initiation. Science 2023; 381:eadi3448. [PMID: 37590370 PMCID: PMC10801813 DOI: 10.1126/science.adi3448] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023]
Abstract
CDC45-MCM2-7-GINS (CMG) helicase assembly is the central event in eukaryotic replication initiation. In yeast, a multi-subunit "pre-loading complex" (pre-LC) accompanies GINS to chromatin-bound MCM2-7, leading to CMG formation. Here, we report that DONSON, a metazoan protein mutated in microcephalic primordial dwarfism, is required for CMG assembly in vertebrates. Using AlphaFold to screen for protein-protein interactions followed by experimental validation, we show that DONSON scaffolds a vertebrate pre-LC containing GINS, TOPBP1, and DNA pol ε. Our evidence suggests that DONSON docks the pre-LC onto MCM2-7, delivering GINS to its binding site in CMG. A patient-derived DONSON mutation compromises CMG assembly and recapitulates microcephalic dwarfism in mice. These results unify our understanding of eukaryotic replication initiation, implicate defective CMG assembly in microcephalic dwarfism, and illustrate how in silico protein-protein interaction screening accelerates mechanistic discovery.
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Affiliation(s)
- Yang Lim
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Lukas Tamayo-Orrego
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Ernst Schmid
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Zygimante Tarnauskaite
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Olga V. Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
- Howard Hughes Medical Institute; Boston, MA 02115, USA
| | - Rhian Gruar
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Sachiko Muramatsu
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS); Mishima, Shizuoka 411-8540, Japan
| | - Luke Lynch
- Biochemistry Department, Stanford School of Medicine; Stanford, CA 94305, USA
| | - Aitana Verdu Schlie
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Paula L. Carroll
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Gheorghe Chistol
- Chemical and Systems Biology Department, Stanford School of Medicine; Stanford, CA 94305, USA
| | - Martin A. M. Reijns
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Masato T. Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS); Mishima, Shizuoka 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI; Mishima, Shizuoka 411-8540, Japan
- Department of Biological Science, The University of Tokyo; Tokyo 113-0033, Japan
| | - Andrew P. Jackson
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Johannes C. Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
- Howard Hughes Medical Institute; Boston, MA 02115, USA
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5
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Rastokina A, Cebrián J, Mozafari N, Mandel NH, Smith CI, Lopes M, Zain R, Mirkin S. Large-scale expansions of Friedreich's ataxia GAA•TTC repeats in an experimental human system: role of DNA replication and prevention by LNA-DNA oligonucleotides and PNA oligomers. Nucleic Acids Res 2023; 51:8532-8549. [PMID: 37216608 PMCID: PMC10484681 DOI: 10.1093/nar/gkad441] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/02/2023] [Accepted: 05/20/2023] [Indexed: 05/24/2023] Open
Abstract
Friedreich's ataxia (FRDA) is caused by expansions of GAA•TTC repeats in the first intron of the human FXN gene that occur during both intergenerational transmissions and in somatic cells. Here we describe an experimental system to analyze large-scale repeat expansions in cultured human cells. It employs a shuttle plasmid that can replicate from the SV40 origin in human cells or be stably maintained in S. cerevisiae utilizing ARS4-CEN6. It also contains a selectable cassette allowing us to detect repeat expansions that accumulated in human cells upon plasmid transformation into yeast. We indeed observed massive expansions of GAA•TTC repeats, making it the first genetically tractable experimental system to study large-scale repeat expansions in human cells. Further, GAA•TTC repeats stall replication fork progression, while the frequency of repeat expansions appears to depend on proteins implicated in replication fork stalling, reversal, and restart. Locked nucleic acid (LNA)-DNA mixmer oligonucleotides and peptide nucleic acid (PNA) oligomers, which interfere with triplex formation at GAA•TTC repeats in vitro, prevented the expansion of these repeats in human cells. We hypothesize, therefore, that triplex formation by GAA•TTC repeats stall replication fork progression, ultimately leading to repeat expansions during replication fork restart.
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Affiliation(s)
| | - Jorge Cebrián
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Negin Mozafari
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | | | - C I Edvard Smith
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Rula Zain
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
- Center for Rare Diseases, Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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6
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Boldinova EO, Makarova AV. Regulation of Human DNA Primase-Polymerase PrimPol. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1139-1155. [PMID: 37758313 DOI: 10.1134/s0006297923080084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 10/03/2023]
Abstract
Transmission of genetic information depends on successful completion of DNA replication. Genomic DNA is subjected to damage on a daily basis. DNA lesions create obstacles for DNA polymerases and can lead to the replication blockage, formation of DNA breaks, cell cycle arrest, and apoptosis. Cells have evolutionary adapted to DNA damage by developing mechanisms allowing elimination of lesions prior to DNA replication (DNA repair) and helping to bypass lesions during DNA synthesis (DNA damage tolerance). The second group of mechanisms includes the restart of DNA synthesis at the sites of DNA damage by DNA primase-polymerase PrimPol. Human PrimPol was described in 2013. The properties and functions of this enzyme have been extensively studied in recent years, but very little is known about the regulation of PrimPol and association between the enzyme dysfunction and diseases. In this review, we described the mechanisms of human PrimPol regulation in the context of DNA replication, discussed in detail interactions of PrimPol with other proteins, and proposed possible pathways for the regulation of human PrimPol activity. The article also addresses the association of PrimPol dysfunction with human diseases.
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Affiliation(s)
- Elizaveta O Boldinova
- Kurchatov Institute National Research Centre, Moscow, 123182, Russia.
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alena V Makarova
- Kurchatov Institute National Research Centre, Moscow, 123182, Russia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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7
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Hoitsma NM, Norris J, Khoang TH, Kaushik V, Chadda R, Antony E, Hedglin M, Freudenthal BD. Mechanistic insight into AP-endonuclease 1 cleavage of abasic sites at stalled replication fork mimics. Nucleic Acids Res 2023; 51:6738-6753. [PMID: 37264933 PMCID: PMC10359615 DOI: 10.1093/nar/gkad481] [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: 11/07/2022] [Revised: 05/13/2023] [Accepted: 05/31/2023] [Indexed: 06/03/2023] Open
Abstract
Many types of damage, including abasic sites, block replicative DNA polymerases causing replication fork uncoupling and generating ssDNA. AP-Endonuclease 1 (APE1) has been shown to cleave abasic sites in ssDNA. Importantly, APE1 cleavage of ssDNA at a replication fork has significant biological implications by generating double strand breaks that could collapse the replication fork. Despite this, the molecular basis and efficiency of APE1 processing abasic sites at replication forks remain elusive. Here, we investigate APE1 cleavage of abasic substrates that mimic APE1 interactions at stalled replication forks or gaps. We determine that APE1 has robust activity on these substrates, like dsDNA, and report rates for cleavage and product release. X-ray structures visualize the APE1 active site, highlighting an analogous mechanism is used to process ssDNA substrates as canonical APE1 activity on dsDNA. However, mutational analysis reveals R177 to be uniquely critical for the APE1 ssDNA cleavage mechanism. Additionally, we investigate the interplay between APE1 and Replication Protein A (RPA), the major ssDNA-binding protein at replication forks, revealing that APE1 can cleave an abasic site while RPA is still bound to the DNA. Together, this work provides molecular level insights into abasic ssDNA processing by APE1, including the presence of RPA.
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Affiliation(s)
- Nicole M Hoitsma
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jessica Norris
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Thu H Khoang
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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8
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Alghoul E, Basbous J, Constantinou A. Compartmentalization of the DNA damage response: Mechanisms and functions. DNA Repair (Amst) 2023; 128:103524. [PMID: 37320957 DOI: 10.1016/j.dnarep.2023.103524] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/17/2023]
Abstract
Cells have evolved an arsenal of molecular mechanisms to respond to continuous alterations in the primary structure of DNA. At the cellular level, DNA damage response proteins accumulate at sites of DNA damage and organize into nuclear foci. As recounted by Errol Friedberg, pioneering work on DNA repair in the 1930 s was stimulated by collaborations between physicists and geneticists. In recent years, the introduction of ideas from physics on self-organizing compartments has taken the field of cell biology by storm. Percolation and phase separation theories are increasingly used to model the self-assembly of compartments, called biomolecular condensates, that selectively concentrate molecules without a surrounding membrane. In this review, we discuss these concepts in the context of the DNA damage response. We discuss how studies of DNA repair foci as condensates can link molecular mechanisms with cell physiological functions, provide new insights into regulatory mechanisms, and open new perspectives for targeting DNA damage responses for therapeutic purposes.
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Affiliation(s)
- Emile Alghoul
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France
| | - Jihane Basbous
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France
| | - Angelos Constantinou
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France.
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9
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Ruis K, Huynh O, Montales K, Barr NA, Michael WM. Delineation of a minimal topoisomerase II binding protein 1 (TOPBP1) for regulated activation of ATR at DNA double-strand breaks. J Biol Chem 2022; 298:101992. [PMID: 35490781 PMCID: PMC9257406 DOI: 10.1016/j.jbc.2022.101992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/18/2022] [Accepted: 04/20/2022] [Indexed: 11/30/2022] Open
Abstract
Topoisomerase II Binding Protein 1 (TOPBP1) is an important activator of the DNA damage response kinase Ataxia Telangiectasia and Rad3-related (ATR), although the mechanism by which this activation occurs is not yet known. TOPBP1 contains nine copies of the BRCA1 C-terminal repeat (BRCT) motif, which allows protein–protein and protein–DNA interactions. TOPBP1 also contains an ATR activation domain (AAD), which physically interacts with ATR and its partner ATR-interacting protein (ATRIP) in a manner that stimulates ATR kinase activity. It is unclear which of TOPBP1’s nine BRCT domains participate in the reaction, as well as the individual roles played by these relevant BRCT domains. To address this knowledge gap, here, we delineated a minimal TOPBP1 that can activate ATR at DNA double-strand breaks in a regulated manner. We named this minimal TOPBP1 “Junior” and we show that Junior is composed of just three regions: BRCT0-2, the AAD, and BRCT7&8. We further defined the individual functions of these three regions by showing that BRCT0-2 is required for recruitment to DNA double-strand breaks and is dispensable thereafter, and that BRCT7&8 is dispensable for recruitment but essential to allow the AAD to multimerize and activate ATR. The delineation of TOPBP1 Junior creates a leaner, simplified, and better understood TOPBP1 and provides insight into the mechanism of ATR activation.
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Affiliation(s)
- Kenna Ruis
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Oanh Huynh
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Katrina Montales
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Nina A Barr
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - W Matthew Michael
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089.
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10
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Mechanisms of loading and release of the 9-1-1 checkpoint clamp. Nat Struct Mol Biol 2022; 29:369-375. [PMID: 35314831 DOI: 10.1038/s41594-022-00741-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/09/2022] [Indexed: 01/14/2023]
Abstract
Single-stranded or double-stranded DNA junctions with recessed 5' ends serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATRMec1. However, the basis for 9-1-1's recruitment to 5' junctions is unclear. Here, we present structures of the yeast checkpoint clamp loader, Rad24-replication factor C (RFC), in complex with 9-1-1 and a 5' junction and in a post-ATP-hydrolysis state. Unexpectedly, 9-1-1 adopts both closed and planar open states in the presence of Rad24-RFC and DNA. Moreover, Rad24-RFC associates with the DNA junction in the opposite orientation of processivity clamp loaders with Rad24 exclusively coordinating the double-stranded region. ATP hydrolysis stimulates conformational changes in Rad24-RFC, leading to disengagement of DNA-loaded 9-1-1. Together, these structures explain 9-1-1's recruitment to 5' junctions and reveal new principles of sliding clamp loading.
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11
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Lebrec V, Poteau M, Morretton JP, Gavet O. Chk1 dynamics in G2 phase upon replication stress predict daughter cell outcome. Dev Cell 2022; 57:638-653.e5. [PMID: 35245445 DOI: 10.1016/j.devcel.2022.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 12/16/2021] [Accepted: 02/08/2022] [Indexed: 12/27/2022]
Abstract
In human cells, ATR/Chk1 signaling couples S phase exit with the expression of mitotic inducers and prevents premature mitosis upon replication stress (RS). Nonetheless, under-replicated DNA can persist at mitosis, prompting chromosomal instability. To decipher how the DNA replication checkpoint (DRC) allows cells to enter mitosis over time upon RS, we developed a FRET-based Chk1 activity sensor. During unperturbed growth, a basal Chk1 activity level is sustained throughout S phase and relies on replication origin firing. Incremental RS triggers stepwise Chk1 over-activation that delays S-phase, suggesting a rheostat-like role for DRC coupled with the replication machinery. Upon RS, Chk1 is inactivated as DNA replication terminates but surprisingly is reactivated in a subset of G2 cells, which relies on Cdk1/2 and Plk1 and prevents mitotic entry. Cells can override active Chk1 signaling and reach mitosis onset, revealing checkpoint adaptation. Cell division following Chk1 reactivation in G2 results in a p53/p21-dependent G1 arrest, eliminating the daughter cells from proliferation.
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Affiliation(s)
- Vivianne Lebrec
- UMR9019 CNRS, Université Paris-Saclay, Gustave Roussy Cancer Campus, 94805 Villejuif Cedex, France
| | - Marion Poteau
- UMR9019 CNRS, Université Paris-Saclay, Gustave Roussy Cancer Campus, 94805 Villejuif Cedex, France
| | - Jean-Philippe Morretton
- UMR9019 CNRS, Université Paris-Saclay, Gustave Roussy Cancer Campus, 94805 Villejuif Cedex, France
| | - Olivier Gavet
- Sorbonne Universités, UPMC Paris VI, UFR927, 75005 Paris, France; UMR9019 CNRS, Université Paris-Saclay, Gustave Roussy Cancer Campus, 94805 Villejuif Cedex, France.
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12
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Lo Furno E, Busseau I, Aze A, Lorenzi C, Saghira C, Danzi MC, Zuchner S, Maiorano D. Translesion DNA synthesis-driven mutagenesis in very early embryogenesis of fast cleaving embryos. Nucleic Acids Res 2021; 50:885-898. [PMID: 34939656 PMCID: PMC8789082 DOI: 10.1093/nar/gkab1223] [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: 06/17/2021] [Revised: 10/22/2021] [Accepted: 12/22/2021] [Indexed: 11/19/2022] Open
Abstract
In early embryogenesis of fast cleaving embryos, DNA synthesis is short and surveillance mechanisms preserving genome integrity are inefficient, implying the possible generation of mutations. We have analyzed mutagenesis in Xenopus laevis and Drosophila melanogaster early embryos. We report the occurrence of a high mutation rate in Xenopus and show that it is dependent upon the translesion DNA synthesis (TLS) master regulator Rad18. Unexpectedly, we observed a homology-directed repair contribution of Rad18 in reducing the mutation load. Genetic invalidation of TLS in the pre-blastoderm Drosophila embryo resulted in reduction of both the hatching rate and single-nucleotide variations on pericentromeric heterochromatin in adult flies. Altogether, these findings indicate that during very early Xenopus and Drosophila embryos TLS strongly contributes to the high mutation rate. This may constitute a previously unforeseen source of genetic diversity contributing to the polymorphisms of each individual with implications for genome evolution and species adaptation.
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Affiliation(s)
- Elena Lo Furno
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Isabelle Busseau
- Systemic Impact of Small Regulatory RNAs Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Antoine Aze
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Claudio Lorenzi
- Machine Learning and Gene Regulation Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Cima Saghira
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Matt C Danzi
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Stephan Zuchner
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Domenico Maiorano
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
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13
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Hoffman RA, MacAlpine HK, MacAlpine DM. Disruption of origin chromatin structure by helicase activation in the absence of DNA replication. Genes Dev 2021; 35:1339-1355. [PMID: 34556529 PMCID: PMC8494203 DOI: 10.1101/gad.348517.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/23/2021] [Indexed: 11/24/2022]
Abstract
Prior to initiation of DNA replication, the eukaryotic helicase, Mcm2-7, must be activated to unwind DNA at replication start sites in early S phase. To study helicase activation within origin chromatin, we constructed a conditional mutant of the polymerase α subunit Cdc17 (or Pol1) to prevent priming and block replication. Recovery of these cells at permissive conditions resulted in the generation of unreplicated gaps at origins, likely due to helicase activation prior to replication initiation. We used micrococcal nuclease (MNase)-based chromatin occupancy profiling under restrictive conditions to study chromatin dynamics associated with helicase activation. Helicase activation in the absence of DNA replication resulted in the disruption and disorganization of chromatin, which extends up to 1 kb from early, efficient replication origins. The CMG holohelicase complex also moves the same distance out from the origin, producing single-stranded DNA that activates the intra-S-phase checkpoint. Loss of the checkpoint did not regulate the progression and stalling of the CMG complex but rather resulted in the disruption of chromatin at both early and late origins. Finally, we found that the local sequence context regulates helicase progression in the absence of DNA replication, suggesting that the helicase is intrinsically less processive when uncoupled from replication.
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Affiliation(s)
- Rachel A Hoffman
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Heather K MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - David M MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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14
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Hydroxyurea-The Good, the Bad and the Ugly. Genes (Basel) 2021; 12:genes12071096. [PMID: 34356112 PMCID: PMC8304116 DOI: 10.3390/genes12071096] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/23/2023] Open
Abstract
Hydroxyurea (HU) is mostly referred to as an inhibitor of ribonucleotide reductase (RNR) and as the agent that is commonly used to arrest cells in the S-phase of the cycle by inducing replication stress. It is a well-known and widely used drug, one which has proved to be effective in treating chronic myeloproliferative disorders and which is considered a staple agent in sickle anemia therapy and—recently—a promising factor in preventing cognitive decline in Alzheimer’s disease. The reversibility of HU-induced replication inhibition also makes it a common laboratory ingredient used to synchronize cell cycles. On the other hand, prolonged treatment or higher dosage of hydroxyurea causes cell death due to accumulation of DNA damage and oxidative stress. Hydroxyurea treatments are also still far from perfect and it has been suggested that it facilitates skin cancer progression. Also, recent studies have shown that hydroxyurea may affect a larger number of enzymes due to its less specific interaction mechanism, which may contribute to further as-yet unspecified factors affecting cell response. In this review, we examine the actual state of knowledge about hydroxyurea and the mechanisms behind its cytotoxic effects. The practical applications of the recent findings may prove to enhance the already existing use of the drug in new and promising ways.
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15
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RepID-deficient cancer cells are sensitized to a drug targeting p97/VCP segregase. Mol Cell Toxicol 2021. [DOI: 10.1007/s13273-021-00121-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
Background
The p97/valosin-containing protein (VCP) complex is a crucial factor for the segregation of ubiquitinated proteins in the DNA damage response and repair pathway.
Objective
We investigated whether blocking the p97/VCP function can inhibit the proliferation of RepID-deficient cancer cells using immunofluorescence, clonogenic survival assay, fluorescence-activated cell sorting, and immunoblotting.
Result
p97/VCP was recruited to chromatin and colocalized with DNA double-strand breaks in RepID-deficient cancer cells that undergo spontaneous DNA damage. Inhibition of p97/VCP induced death of RepID-depleted cancer cells. This study highlights the potential of targeting p97/VCP complex as an anticancer therapeutic approach.
Conclusion
Our results show that RepID is required to prevent excessive DNA damage at the endogenous levels. Localization of p97/VCP to DSB sites was induced based on spontaneous DNA damage in RepID-depleted cancer cells. Anticancer drugs targeting p97/VCP may be highly potent in RepID-deficient cells. Therefore, we suggest that p97/VCP inhibitors synergize with RepID depletion to kill cancer cells.
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16
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Ercilla A, Benada J, Amitash S, Zonderland G, Baldi G, Somyajit K, Ochs F, Costanzo V, Lukas J, Toledo L. Physiological Tolerance to ssDNA Enables Strand Uncoupling during DNA Replication. Cell Rep 2021; 30:2416-2429.e7. [PMID: 32075739 DOI: 10.1016/j.celrep.2020.01.067] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/17/2019] [Accepted: 01/22/2020] [Indexed: 12/20/2022] Open
Abstract
It has been long assumed that normally leading strand synthesis must proceed coordinated with the lagging strand to prevent strand uncoupling and the pathological accumulation of single-stranded DNA (ssDNA) in the cell, a dogma recently challenged by in vitro studies in prokaryotes. Here, we report that human DNA polymerases can function independently at each strand in vivo and that the resulting strand uncoupling is supported physiologically by a cellular tolerance to ssDNA. Active forks rapidly accumulate ssDNA at the lagging strand when POLA1 is inhibited without triggering a stress response, despite ssDNA formation being considered a hallmark of replication stress. Acute POLA1 inhibition causes a lethal RPA exhaustion, but cells can duplicate their DNA with limited POLA1 activity and exacerbated strand uncoupling as long as RPA molecules suffice to protect the elevated ssDNA. Although robust, this uncoupled mode of DNA replication is also an in-built weakness that can be targeted for cancer treatment.
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Affiliation(s)
- Amaia Ercilla
- Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Jan Benada
- Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Sampath Amitash
- Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Gijs Zonderland
- Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Giorgio Baldi
- DNA Metabolism Laboratory, FIRC Institute for Molecular Oncology (IFOM), Milan 20139, Italy
| | - Kumar Somyajit
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Fena Ochs
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Vincenzo Costanzo
- DNA Metabolism Laboratory, FIRC Institute for Molecular Oncology (IFOM), Milan 20139, Italy
| | - Jiri Lukas
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Luis Toledo
- Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.
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17
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Frattini C, Promonet A, Alghoul E, Vidal-Eychenie S, Lamarque M, Blanchard MP, Urbach S, Basbous J, Constantinou A. TopBP1 assembles nuclear condensates to switch on ATR signaling. Mol Cell 2021; 81:1231-1245.e8. [PMID: 33503405 DOI: 10.1016/j.molcel.2020.12.049] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/01/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022]
Abstract
ATR checkpoint signaling is crucial for cellular responses to DNA replication impediments. Using an optogenetic platform, we show that TopBP1, the main activator of ATR, self-assembles extensively to yield micrometer-sized condensates. These opto-TopBP1 condensates are functional entities organized in tightly packed clusters of spherical nano-particles. TopBP1 condensates are reversible, occasionally fuse, and co-localize with TopBP1 partner proteins. We provide evidence that TopBP1 condensation is a molecular switch that amplifies ATR activity to phosphorylate checkpoint kinase 1 (Chk1) and slow down replication forks. Single amino acid substitutions of key residues in the intrinsically disordered ATR activation domain disrupt TopBP1 condensation and consequently ATR/Chk1 signaling. In physiologic salt concentration and pH, purified TopBP1 undergoes liquid-liquid phase separation in vitro. We propose that the actuation mechanism of ATR signaling is the assembly of TopBP1 condensates driven by highly regulated multivalent and cooperative interactions.
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Affiliation(s)
- Camilla Frattini
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Alexy Promonet
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Emile Alghoul
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | | | - Marie Lamarque
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | | | - Serge Urbach
- Institut de Génomique Fonctionnelle, CNRS INSERM, Université de Montpellier, Montpellier, France
| | - Jihane Basbous
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France.
| | - Angelos Constantinou
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France.
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18
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Conti BA, Smogorzewska A. Mechanisms of direct replication restart at stressed replisomes. DNA Repair (Amst) 2020; 95:102947. [PMID: 32853827 PMCID: PMC7669714 DOI: 10.1016/j.dnarep.2020.102947] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/02/2020] [Accepted: 08/04/2020] [Indexed: 02/09/2023]
Affiliation(s)
- Brooke A Conti
- Laboratory of Genome Maintenance, The Rockefeller University, New York 10065, USA
| | - Agata Smogorzewska
- Laboratory of Genome Maintenance, The Rockefeller University, New York 10065, USA.
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19
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Distinct roles of XRCC1 in genome integrity in Xenopus egg extracts. Biochem J 2020; 476:3791-3804. [PMID: 31808793 DOI: 10.1042/bcj20190798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 02/06/2023]
Abstract
Oxidative DNA damage represents one of the most abundant DNA lesions. It remains unclear how DNA repair and DNA damage response (DDR) pathways are co-ordinated and regulated following oxidative stress. While XRCC1 has been implicated in DNA repair, it remains unknown how exactly oxidative DNA damage is repaired and sensed by XRCC1. In this communication, we have demonstrated evidence that XRCC1 is dispensable for ATR-Chk1 DDR pathway following oxidative stress in Xenopus egg extracts. Whereas APE2 is essential for SSB repair, XRCC1 is not required for the repair of defined SSB and gapped plasmids with a 5'-OH or 5'-P terminus, suggesting that XRCC1 and APE2 may contribute to SSB repair via different mechanisms. Neither Polymerase beta nor Polymerase alpha is important for the repair of defined SSB structure. Nonetheless, XRCC1 is important for the repair of DNA damage following oxidative stress. Our observations suggest distinct roles of XRCC1 for genome integrity in oxidative stress in Xenopus egg extracts.
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20
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Active Replication Checkpoint Drives Genome Instability in Fission Yeast mcm4 Mutant. Mol Cell Biol 2020; 40:MCB.00033-20. [PMID: 32341083 DOI: 10.1128/mcb.00033-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023] Open
Abstract
Upon replication fork arrest, the replication checkpoint kinase Cds1 is stimulated to preserve genome integrity. Robust activation of Cds1 in response to hydroxyurea prevents the endonuclease Mus81 from cleaving the stalled replication fork inappropriately. However, we find that the response is different in temperature-sensitive mcm4 mutants, affecting a subunit of the MCM replicative helicase. We show that Cds1 inhibition of Mus81 promotes genomic instability and allows mcm4-dg cells to evade cell cycle arrest. Cds1 regulation of Mus81 activity also contributes to the formation of the replication stress-induced DNA damage markers replication protein A (RPA) and Ku. These results identify a surprising role for Cds1 in driving DNA damage and disrupted chromosomal segregation under certain conditions of replication stress.
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21
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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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22
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Single-stranded DNA damage: Protecting the single-stranded DNA from chemical attack. DNA Repair (Amst) 2020; 87:102804. [PMID: 31981739 DOI: 10.1016/j.dnarep.2020.102804] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 01/18/2020] [Accepted: 01/18/2020] [Indexed: 01/08/2023]
Abstract
Cellular processes, such as DNA replication, recombination and transcription, require DNA strands separation and single-stranded DNA is formation. The single-stranded DNA is promptly wrapped by human single-stranded DNA binding proteins, replication protein A (RPA) complex. RPA binding not only prevent nuclease degradation and annealing, but it also coordinates cell-cycle checkpoint activation and DNA repair. However, RPA binding offers little protection against the chemical modification of DNA bases. This review focuses on the type of DNA base damage that occurs in single-stranded DNA and how the damage is rectified in human cells. The discovery of DNA repair proteins, such as ALKBH3, AGT, UNG2, NEIL3, being able to repair the damaged base in the single-stranded DNA, renewed the interest to study single-stranded DNA repair. These mechanistically different proteins work independently from each other with the overarching goal of increasing fidelity of recombination and promoting error-free replication.
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23
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Singh B, Bisht KK, Upadhyay U, Kushwaha AC, Nanda JS, Srivastava S, Saini JK, Klar AJS, Singh J. Role of Cdc23/Mcm10 in generating the ribonucleotide imprint at the mat1 locus in fission yeast. Nucleic Acids Res 2019; 47:3422-3433. [PMID: 30759238 PMCID: PMC6468313 DOI: 10.1093/nar/gkz092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 01/31/2019] [Accepted: 02/10/2019] [Indexed: 01/28/2023] Open
Abstract
The developmental asymmetry of fission yeast daughter cells derives from inheriting ‘older Watson’ versus ‘older Crick’ DNA strand from the parental cell, strands that are complementary but not identical with each other. A novel DNA strand-specific ‘imprint’, installed during DNA replication at the mating-type locus (mat1), imparts competence for cell type inter-conversion to one of the two chromosome replicas. The catalytic subunit of DNA Polymerase α (Polα) has been implicated in the imprinting process. Based on its known biochemical function, Polα might install the mat1 imprint during lagging strand synthesis. The nature of the imprint is not clear: it is either a nick or a ribonucleotide insertion. Our investigations do not support a direct role of Polα in nicking through putative endonuclease domains but confirm its indirect role in installing an alkali-labile moiety as the imprint. While ruling out the role of the primase subunit of Polα holoenzyme, we find that mutations in the Polα-recruitment and putative primase homology domain in Mcm10/Cdc23 abrogate the ribonucleotide imprint formation. These results, while confirming the ribonucleotide nature of the imprint suggest the possibility of a direct role of Mcm10/Cdc23 in installing it in cooperation with Polα and Swi1.
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Affiliation(s)
- Balveer Singh
- Institute of Genetics and Development of Rennes, Faculte de Medecine, Campus santé de Villejean, 2 avenue du Professor Leon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Kamlesh K Bisht
- Translational Discovery Biology, (Immuno-Oncology), Bristol-Myers Squibb Route 206 & Province Line Road, Princeton, NJ 08543, USA
| | - Udita Upadhyay
- Department of Anesthesiology, RMSB 8022, 1600 NW, 10th Ave., Miami, FL 33136, USA
| | | | - Jagpreet Singh Nanda
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - Suchita Srivastava
- QC Division, Central Research Institute, Kasauli, Himachal Pradesh 173204, India
| | - Jai Kumar Saini
- Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Amar J S Klar
- Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Building 539, Room 154, Frederick, MD 21702-1201, USA
| | - Jagmohan Singh
- Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
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24
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Kermi C, Aze A, Maiorano D. Preserving Genome Integrity During the Early Embryonic DNA Replication Cycles. Genes (Basel) 2019; 10:genes10050398. [PMID: 31137726 PMCID: PMC6563053 DOI: 10.3390/genes10050398] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
During the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed DNA damage response and, in certain animal species, a highly contracted S-phase. This raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. Recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate genetic and genomic alterations, most likely due to restricted cellular functions, in particular reduced DNA synthesis quality control. These findings may explain the low rate of successful development in mammals and the occurrence of diseases, such as abnormal developmental features and cancer. In this review, we will discuss recent findings in this field and put forward perspectives to further study this fascinating question.
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Affiliation(s)
- Chames Kermi
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
| | - Antoine Aze
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
| | - Domenico Maiorano
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
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25
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RNA insertion in DNA as the imprint moiety: the fission yeast paradigm. Curr Genet 2019; 65:1301-1306. [PMID: 31076844 DOI: 10.1007/s00294-019-00991-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 10/26/2022]
Abstract
This review elaborates on the findings of a new report which possibly resolves the biochemical nature of a novel type of DNA imprint as ribonucleotide and the mechanism of its formation during cell differentiation in fission yeast. The process of mating-type switching in fission yeast, Schizosaccharomyces pombe, displays characteristics of a typical mammalian stem cell lineage, wherein a cell divides to produce an identical cell and a differentiated cell after every two cell divisions. This developmental asymmetry has been ascribed to play a role in generation of a DNA strand-specific imprint at the mat1 locus during lagging strand synthesis and its segregation to one of the two daughter cells by the process of asymmetric, semi-conservative DNA replication. The nature of this imprint and mechanisms of its generation have been a subject of research and debate. A recent report by Singh et al. (Nucleic Acids Res 47:3422-3433. https://doi.org/10.1093/nar/gkz092 , 2019) provides compelling evidence in support of a ribonucleotide as the imprint moiety within the mat1 DNA and demonstrates the role of Mcm10/Cdc23, an important, evolutionarily conserved component of DNA replication machinery in eukaryotes, in installing the imprint through a non-canonical primase activity and interaction with DNA Polα and Swi1. The high degree of conservation of DNA replication machinery, especially the presence of the T7 gene 4 helicase/primase domain in the mammalian orthologs of Mcm10 suggests that similar mechanisms of DNA imprinting may play a role during cell differentiation in metazoans.
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26
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Taylor MRG, Yeeles JTP. Dynamics of Replication Fork Progression Following Helicase-Polymerase Uncoupling in Eukaryotes. J Mol Biol 2019; 431:2040-2049. [PMID: 30894292 PMCID: PMC6525111 DOI: 10.1016/j.jmb.2019.03.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/09/2019] [Accepted: 03/10/2019] [Indexed: 12/11/2022]
Abstract
Leading-strand polymerase stalling at DNA damage impairs replication fork progression. Using biochemical approaches, we show this arises due to both slower template unwinding following helicase-polymerase uncoupling and establishment of prolonged stalled fork structures. Fork slowing and stalling occur at structurally distinct lesions, are always associated with continued lagging-strand synthesis, are observed when either Pol ε or Pol δ stalls at leading-strand damage, and do not require specific helicase-polymerase coupling factors. Hence, the key trigger for these replisome-intrinsic responses is cessation of leading-strand polymerization, revealing this as a crucial driver of normal replication fork rates. We propose that this helps balance the need for sufficient uncoupling to activate the DNA replication checkpoint with excessive destabilizing single-stranded DNA exposure in eukaryotes.
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Affiliation(s)
- Martin R G Taylor
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Joseph T P Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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27
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Lin Y, Ha A, Yan S. Methods for Studying DNA Single-Strand Break Repair and Signaling in Xenopus laevis Egg Extracts. Methods Mol Biol 2019; 1999:161-172. [PMID: 31127575 PMCID: PMC6550457 DOI: 10.1007/978-1-4939-9500-4_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
DNA single-strand breaks (SSBs) are the most common type of DNA lesions as they are generated approximately 10,000 times per mammalian cell each day. Unrepaired SSBs compromise DNA replication and transcription programs, leading to genome instability, and have been implicated in many diseases including cancer. In this chapter, we introduce methods to study the ATR-Chk1 DNA damage response (DDR) pathway and DNA repair pathway in response to a site-specific, defined SSB plasmid in Xenopus laevis egg extracts. This experimental system can be applied in future studies to reveal many aspects of the molecular mechanisms of SSB repair and signaling in eukaryotes.
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Affiliation(s)
- Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Anh Ha
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA.
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28
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Irony-Tur Sinai M, Kerem B. Genomic instability in fragile sites-still adding the pieces. Genes Chromosomes Cancer 2018; 58:295-304. [PMID: 30525255 DOI: 10.1002/gcc.22715] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 12/19/2022] Open
Abstract
Common fragile sites (CFSs) are specific genomic regions in normal chromosomes that exhibit genomic instability under DNA replication stress. As replication stress is an early feature of cancer development, CFSs are involved in the signature of genomic instability found in malignant tumors. The landscape of CFSs is tissue-specific and differs under different replication stress inducers. Nevertheless, the features underlying CFS sensitivity to replication stress are shared. Here, we review the events generating replication stress and discuss the unique characteristics of CFS regions and the cellular responses aimed to stabilizing these regions.
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Affiliation(s)
- Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
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29
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The Initial Response of a Eukaryotic Replisome to DNA Damage. Mol Cell 2018; 70:1067-1080.e12. [PMID: 29944888 PMCID: PMC6024075 DOI: 10.1016/j.molcel.2018.04.022] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/09/2018] [Accepted: 04/26/2018] [Indexed: 01/27/2023]
Abstract
The replisome must overcome DNA damage to ensure complete chromosome replication. Here, we describe the earliest events in this process by reconstituting collisions between a eukaryotic replisome, assembled with purified proteins, and DNA damage. Lagging-strand lesions are bypassed without delay, leaving daughter-strand gaps roughly the size of an Okazaki fragment. In contrast, leading-strand polymerase stalling significantly impacts replication fork progression. We reveal that the core replisome itself can bypass leading-strand damage by re-priming synthesis beyond it. Surprisingly, this restart activity is rare, mainly due to inefficient leading-strand re-priming, rather than single-stranded DNA exposure or primer extension. We find several unanticipated mechanistic distinctions between leading- and lagging-strand priming that we propose control the replisome’s initial response to DNA damage. Notably, leading-strand restart was specifically stimulated by RPA depletion, which can occur under conditions of replication stress. Our results have implications for pathway choice at stalled forks and priming at DNA replication origins. Reconstitution of collisions between a eukaryotic replisome and DNA damage Leading-strand damage specifically causes fork stalling and uncoupling The eukaryotic replisome can re-initiate leading-strands downstream of DNA damage Multiple mechanistic differences exist between leading- and lagging-strand priming
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30
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Stewart JA, Wang Y, Ackerson SM, Schuck PL. Emerging roles of CST in maintaining genome stability and human disease. Front Biosci (Landmark Ed) 2018; 23:1564-1586. [PMID: 29293451 DOI: 10.2741/4661] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The human CTC1-STN1-TEN1 (CST) complex is a single-stranded DNA binding protein that shares homology with RPA and interacts with DNA polymerase alpha/primase. CST complexes are conserved from yeasts to humans and function in telomere maintenance. A common role of CST across species is in the regulation of telomere extension by telomerase and C-strand fill-in synthesis. However, recent studies also indicate that CST promotes telomere duplex replication as well the rescue of stalled DNA replication at non-telomeric sites. Furthermore, CST dysfunction and mutation is associated with several genetic diseases and cancers. In this review, we will summarize what is known about CST with a particular focus on the emerging roles of CST in DNA replication and human disease.
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Affiliation(s)
- Jason A Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA,
| | - Yilin Wang
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Stephanie M Ackerson
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Percy Logan Schuck
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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31
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Quinet A, Lerner LK, Martins DJ, Menck CFM. Filling gaps in translesion DNA synthesis in human cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:127-142. [PMID: 30442338 DOI: 10.1016/j.mrgentox.2018.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 02/21/2018] [Indexed: 01/06/2023]
Abstract
During DNA replication, forks may encounter unrepaired lesions that hamper DNA synthesis. Cells have universal strategies to promote damage bypass allowing cells to survive. DNA damage tolerance can be performed upon template switch or by specialized DNA polymerases, known as translesion (TLS) polymerases. Human cells count on more than eleven TLS polymerases and this work reviews the functions of some of these enzymes: Rev1, Pol η, Pol ι, Pol κ, Pol θ and Pol ζ. The mechanisms of damage bypass vary according to the lesion, as well as to the TLS polymerases available, and may occur directly at the fork during replication. Alternatively, the lesion may be skipped, leaving a single-stranded DNA gap that will be replicated later. Details of the participation of these enzymes are revised for the replication of damaged template. TLS polymerases also have functions in other cellular processes. These include involvement in somatic hypermutation in immunoglobulin genes, direct participation in recombination and repair processes, and contributing to replicating noncanonical DNA structures. The importance of DNA damage replication to cell survival is supported by recent discoveries that certain genes encoding TLS polymerases are induced in response to DNA damaging agents, protecting cells from a subsequent challenge to DNA replication. We retrace the findings on these genotoxic (adaptive) responses of human cells and show the common aspects with the SOS responses in bacteria. Paradoxically, although TLS of DNA damage is normally an error prone mechanism, in general it protects from carcinogenesis, as evidenced by increased tumorigenesis in xeroderma pigmentosum variant patients, who are deficient in Pol η. As these TLS polymerases also promote cell survival, they constitute an important mechanism by which cancer cells acquire resistance to genotoxic chemotherapy. Therefore, the TLS polymerases are new potential targets for improving therapy against tumors.
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Affiliation(s)
- Annabel Quinet
- Saint Louis University School of Medicine, St. Louis, MO, United States.
| | - Leticia K Lerner
- MRC Laboratory of Molecular Biology,Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Davi J Martins
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Carlos F M Menck
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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32
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Cupello S, Richardson C, Yan S. Cell-free Xenopus egg extracts for studying DNA damage response pathways. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 60:229-236. [PMID: 27160070 DOI: 10.1387/ijdb.160113sy] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In response to a variety of DNA replication stress or DNA damaging agents, the DNA damage response (DDR) pathways are triggered for cells to coordinate DNA repair, cell cycle checkpoints, apoptosis, and senescence. Cell-free Xenopus egg extracts, derived from the eggs of African clawed frogs (Xenopus laevis), have been widely used for studies concerning DDR pathways. In this review, we focus on how different experimental systems have been established using Xenopus egg extracts to investigate the DDR pathways that are activated in response to DNA replication stress, double-strand breaks (DSBs), inter-strand crosslinks (ICLs), and oxidative stress. We summarize how molecular details of DDR pathways are dissected by the mechanistic studies with Xenopus egg extracts. We also provide an update on the regulation of translesion DNA synthesis (TLS) polymerases (Pol ĸ and REV1) in the DDR pathways. A better understanding of DDR pathways using Xenopus egg extracts has opened new avenues for future cancer therapeutics. Finally, we offer our perspectives of future directions for studies of DDR pathways with Xenopus egg extracts.
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Affiliation(s)
- Steven Cupello
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA
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33
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Saldivar JC, Cortez D, Cimprich KA. The essential kinase ATR: ensuring faithful duplication of a challenging genome. Nat Rev Mol Cell Biol 2017; 18:622-636. [PMID: 28811666 DOI: 10.1038/nrm.2017.67] [Citation(s) in RCA: 527] [Impact Index Per Article: 75.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
One way to preserve a rare book is to lock it away from all potential sources of damage. Of course, an inaccessible book is also of little use, and the paper and ink will continue to degrade with age in any case. Like a book, the information stored in our DNA needs to be read, but it is also subject to continuous assault and therefore needs to be protected. In this Review, we examine how the replication stress response that is controlled by the kinase ataxia telangiectasia and Rad3-related (ATR) senses and resolves threats to DNA integrity so that the DNA remains available to read in all of our cells. We discuss the multiple data that have revealed an elegant yet increasingly complex mechanism of ATR activation. This involves a core set of components that recruit ATR to stressed replication forks, stimulate kinase activity and amplify ATR signalling. We focus on the activities of ATR in the control of cell cycle checkpoints, origin firing and replication fork stability, and on how proper regulation of these processes is crucial to ensure faithful duplication of a challenging genome.
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Affiliation(s)
- Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
| | - David Cortez
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
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34
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Bournique E, Dall'Osto M, Hoffmann JS, Bergoglio V. Role of specialized DNA polymerases in the limitation of replicative stress and DNA damage transmission. Mutat Res 2017; 808:62-73. [PMID: 28843435 DOI: 10.1016/j.mrfmmm.2017.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 01/31/2023]
Abstract
Replication stress is a strong and early driving force for genomic instability and tumor development. Beside replicative DNA polymerases, an emerging group of specialized DNA polymerases is involved in the technical assistance of the replication machinery in order to prevent replicative stress and its deleterious consequences. During S-phase, altered progression of the replication fork by endogenous or exogenous impediments induces replicative stress, causing cells to reach mitosis with genomic regions not fully duplicated. Recently, specific mechanisms to resolve replication intermediates during mitosis with the aim of limiting DNA damage transmission to daughter cells have been identified. In this review, we detail the two major actions of specialized DNA polymerases that limit DNA damage transmission: the prevention of replicative stress by non-B DNA replication and the recovery of stalled replication forks.
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Affiliation(s)
- Elodie Bournique
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Marina Dall'Osto
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Jean-Sébastien Hoffmann
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Valérie Bergoglio
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France.
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35
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Kolinjivadi AM, Sannino V, De Antoni A, Zadorozhny K, Kilkenny M, Técher H, Baldi G, Shen R, Ciccia A, Pellegrini L, Krejci L, Costanzo V. Smarcal1-Mediated Fork Reversal Triggers Mre11-Dependent Degradation of Nascent DNA in the Absence of Brca2 and Stable Rad51 Nucleofilaments. Mol Cell 2017; 67:867-881.e7. [PMID: 28757209 PMCID: PMC5594205 DOI: 10.1016/j.molcel.2017.07.001] [Citation(s) in RCA: 265] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/14/2017] [Accepted: 06/29/2017] [Indexed: 12/18/2022]
Abstract
Brca2 deficiency causes Mre11-dependent degradation of nascent DNA at stalled forks, leading to cell lethality. To understand the molecular mechanisms underlying this process, we isolated Xenopus laevis Brca2. We demonstrated that Brca2 protein prevents single-stranded DNA gap accumulation at replication fork junctions and behind them by promoting Rad51 binding to replicating DNA. Without Brca2, forks with persistent gaps are converted by Smarcal1 into reversed forks, triggering extensive Mre11-dependent nascent DNA degradation. Stable Rad51 nucleofilaments, but not RPA or Rad51T131P mutant proteins, directly prevent Mre11-dependent DNA degradation. Mre11 inhibition instead promotes reversed fork accumulation in the absence of Brca2. Rad51 directly interacts with the Pol α N-terminal domain, promoting Pol α and δ binding to stalled replication forks. This interaction likely promotes replication fork restart and gap avoidance. These results indicate that Brca2 and Rad51 prevent formation of abnormal DNA replication intermediates, whose processing by Smarcal1 and Mre11 predisposes to genome instability. Brca2 promotes Rad51 binding to replicating DNA, preventing fork gaps Stable Rad51 nucleofilaments directly protect DNA from Mre11-dependent degradation Smarcal1-dependent fork reversal triggers extensive Mre11-dependent DNA degradation Rad51 directly interacts with Pol α, promoting its function at stalled forks
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Affiliation(s)
- Arun Mouli Kolinjivadi
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Vincenzo Sannino
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Anna De Antoni
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Karina Zadorozhny
- Department of Biology, Masaryk University, Brno 625 00, Czech Republic
| | - Mairi Kilkenny
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1GA, UK
| | - Hervé Técher
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Giorgio Baldi
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Rong Shen
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1GA, UK
| | - Alberto Ciccia
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Luca Pellegrini
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1GA, UK.
| | - Lumir Krejci
- Department of Biology, Masaryk University, Brno 625 00, Czech Republic; National Centre for Biomolecular Research, Masaryk University, Brno 625 00, Czech Republic; International Clinical Research Center, St. Anne's University Hospital, Brno 656 91, Czech Republic.
| | - Vincenzo Costanzo
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy.
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36
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Hedglin M, Benkovic SJ. Eukaryotic Translesion DNA Synthesis on the Leading and Lagging Strands: Unique Detours around the Same Obstacle. Chem Rev 2017; 117:7857-7877. [PMID: 28497687 PMCID: PMC5662946 DOI: 10.1021/acs.chemrev.7b00046] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During S-phase, minor DNA damage may be overcome by DNA damage tolerance (DDT) pathways that bypass such obstacles, postponing repair of the offending damage to complete the cell cycle and maintain cell survival. In translesion DNA synthesis (TLS), specialized DNA polymerases replicate the damaged DNA, allowing stringent DNA synthesis by a replicative polymerase to resume beyond the offending damage. Dysregulation of this DDT pathway in human cells leads to increased mutation rates that may contribute to the onset of cancer. Furthermore, TLS affords human cancer cells the ability to counteract chemotherapeutic agents that elicit cell death by damaging DNA in actively replicating cells. Currently, it is unclear how this critical pathway unfolds, in particular, where and when TLS occurs on each template strand. Given the semidiscontinuous nature of DNA replication, it is likely that TLS on the leading and lagging strand templates is unique for each strand. Since the discovery of DDT in the late 1960s, most studies on TLS in eukaryotes have focused on DNA lesions resulting from ultraviolet (UV) radiation exposure. In this review, we revisit these and other related studies to dissect the step-by-step intricacies of this complex process, provide our current understanding of TLS on leading and lagging strand templates, and propose testable hypotheses to gain further insights.
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Affiliation(s)
- Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Stephen J. Benkovic
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, U.S.A
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37
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Blumenfeld B, Ben-Zimra M, Simon I. Perturbations in the Replication Program Contribute to Genomic Instability in Cancer. Int J Mol Sci 2017; 18:E1138. [PMID: 28587102 PMCID: PMC5485962 DOI: 10.3390/ijms18061138] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/08/2017] [Accepted: 05/21/2017] [Indexed: 12/14/2022] Open
Abstract
Cancer and genomic instability are highly impacted by the deoxyribonucleic acid (DNA) replication program. Inaccuracies in DNA replication lead to the increased acquisition of mutations and structural variations. These inaccuracies mainly stem from loss of DNA fidelity due to replication stress or due to aberrations in the temporal organization of the replication process. Here we review the mechanisms and impact of these major sources of error to the replication program.
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Affiliation(s)
- Britny Blumenfeld
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Micha Ben-Zimra
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
- Pharmacology and Experimental Therapeutics Unit, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Itamar Simon
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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38
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Hoogenboom WS, Klein Douwel D, Knipscheer P. Xenopus egg extract: A powerful tool to study genome maintenance mechanisms. Dev Biol 2017; 428:300-309. [PMID: 28427716 DOI: 10.1016/j.ydbio.2017.03.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/29/2017] [Accepted: 03/29/2017] [Indexed: 01/09/2023]
Abstract
DNA repair pathways are crucial to maintain the integrity of our genome and prevent genetic diseases such as cancer. There are many different types of DNA damage and specific DNA repair mechanisms have evolved to deal with these lesions. In addition to these repair pathways there is an extensive signaling network that regulates processes important for repair, such as cell cycle control and transcription. Despite extensive research, DNA damage repair and signaling are not fully understood. In vitro systems such as the Xenopus egg extract system, have played, and still play, an important role in deciphering the molecular details of these processes. Xenopus laevis egg extracts contain all factors required to efficiently perform DNA repair outside a cell, using mechanisms conserved in humans. These extracts have been used to study several genome maintenance pathways, including mismatch repair, non-homologous end joining, ICL repair, DNA damage checkpoint activation, and replication fork stability. Here we describe how the Xenopus egg extract system, in combination with specifically designed DNA templates, contributed to our detailed understanding of these pathways.
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Affiliation(s)
- Wouter S Hoogenboom
- Hubrecht Institute - KNAW, University Medical Center Utrecht & Cancer GenomiCs Netherlands, The Netherlands
| | - Daisy Klein Douwel
- Hubrecht Institute - KNAW, University Medical Center Utrecht & Cancer GenomiCs Netherlands, The Netherlands
| | - Puck Knipscheer
- Hubrecht Institute - KNAW, University Medical Center Utrecht & Cancer GenomiCs Netherlands, The Netherlands.
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39
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S-phase checkpoint regulations that preserve replication and chromosome integrity upon dNTP depletion. Cell Mol Life Sci 2017; 74:2361-2380. [PMID: 28220209 PMCID: PMC5487892 DOI: 10.1007/s00018-017-2474-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 12/29/2016] [Accepted: 01/23/2017] [Indexed: 11/18/2022]
Abstract
DNA replication stress, an important source of genomic instability, arises upon different types of DNA replication perturbations, including those that stall replication fork progression. Inhibitors of the cellular pool of deoxynucleotide triphosphates (dNTPs) slow down DNA synthesis throughout the genome. Following depletion of dNTPs, the highly conserved replication checkpoint kinase pathway, also known as the S-phase checkpoint, preserves the functionality and structure of stalled DNA replication forks and prevents chromosome fragmentation. The underlying mechanisms involve pathways extrinsic to replication forks, such as those involving regulation of the ribonucleotide reductase activity, the temporal program of origin firing, and cell cycle transitions. In addition, the S-phase checkpoint modulates the function of replisome components to promote replication integrity. This review summarizes the various functions of the replication checkpoint in promoting replication fork stability and genome integrity in the face of replication stress caused by dNTP depletion.
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40
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Regulation of DNA Replication in Early Embryonic Cleavages. Genes (Basel) 2017; 8:genes8010042. [PMID: 28106858 PMCID: PMC5295036 DOI: 10.3390/genes8010042] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 11/18/2022] Open
Abstract
Early embryonic cleavages are characterized by short and highly synchronous cell cycles made of alternating S- and M-phases with virtually absent gap phases. In this contracted cell cycle, the duration of DNA synthesis can be extraordinarily short. Depending on the organism, the whole genome of an embryo is replicated at a speed that is between 20 to 60 times faster than that of a somatic cell. Because transcription in the early embryo is repressed, DNA synthesis relies on a large stockpile of maternally supplied proteins stored in the egg representing most, if not all, cellular genes. In addition, in early embryonic cell cycles, both replication and DNA damage checkpoints are inefficient. In this article, we will review current knowledge on how DNA synthesis is regulated in early embryos and discuss possible consequences of replicating chromosomes with little or no quality control.
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41
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Barnes R, Eckert K. Maintenance of Genome Integrity: How Mammalian Cells Orchestrate Genome Duplication by Coordinating Replicative and Specialized DNA Polymerases. Genes (Basel) 2017; 8:genes8010019. [PMID: 28067843 PMCID: PMC5295014 DOI: 10.3390/genes8010019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/19/2016] [Accepted: 12/27/2016] [Indexed: 12/30/2022] Open
Abstract
Precise duplication of the human genome is challenging due to both its size and sequence complexity. DNA polymerase errors made during replication, repair or recombination are central to creating mutations that drive cancer and aging. Here, we address the regulation of human DNA polymerases, specifically how human cells orchestrate DNA polymerases in the face of stress to complete replication and maintain genome stability. DNA polymerases of the B-family are uniquely adept at accurate genome replication, but there are numerous situations in which one or more additional DNA polymerases are required to complete genome replication. Polymerases of the Y-family have been extensively studied in the bypass of DNA lesions; however, recent research has revealed that these polymerases play important roles in normal human physiology. Replication stress is widely cited as contributing to genome instability, and is caused by conditions leading to slowed or stalled DNA replication. Common Fragile Sites epitomize “difficult to replicate” genome regions that are particularly vulnerable to replication stress, and are associated with DNA breakage and structural variation. In this review, we summarize the roles of both the replicative and Y-family polymerases in human cells, and focus on how these activities are regulated during normal and perturbed genome replication.
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Affiliation(s)
- Ryan Barnes
- Biomedical Sciences Graduate Program, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
| | - Kristin Eckert
- Departments of Pathology and Biochemistry & Molecular Biology, The Jake Gittlen Laboratories for Cancer Research, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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42
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Feng Y, Vlassis A, Roques C, Lalonde ME, González-Aguilera C, Lambert JP, Lee SB, Zhao X, Alabert C, Johansen JV, Paquet E, Yang XJ, Gingras AC, Côté J, Groth A. BRPF3-HBO1 regulates replication origin activation and histone H3K14 acetylation. EMBO J 2015; 35:176-92. [PMID: 26620551 DOI: 10.15252/embj.201591293] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 11/03/2015] [Indexed: 12/23/2022] Open
Abstract
During DNA replication, thousands of replication origins are activated across the genome. Chromatin architecture contributes to origin specification and usage, yet it remains unclear which chromatin features impact on DNA replication. Here, we perform a RNAi screen for chromatin regulators implicated in replication control by measuring RPA accumulation upon replication stress. We identify six factors required for normal rates of DNA replication and characterize a function of the bromodomain and PHD finger-containing protein 3 (BRPF3) in replication initiation. BRPF3 forms a complex with HBO1 that specifically acetylates histone H3K14, and genomewide analysis shows high enrichment of BRPF3, HBO1 and H3K14ac at ORC1-binding sites and replication origins found in the vicinity of TSSs. Consistent with this, BRPF3 is necessary for H3K14ac at selected origins and efficient origin activation. CDC45 recruitment, but not MCM2-7 loading, is impaired in BRPF3-depleted cells, identifying a BRPF3-dependent function of HBO1 in origin activation that is complementary to its role in licencing. We thus propose that BRPF3-HBO1 acetylation of histone H3K14 around TSS facilitates efficient activation of nearby replication origins.
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Affiliation(s)
- Yunpeng Feng
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Arsenios Vlassis
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Céline Roques
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Axis-CHU de Québec Research Center, Quebec City, QC, Canada
| | - Marie-Eve Lalonde
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Axis-CHU de Québec Research Center, Quebec City, QC, Canada
| | - Cristina González-Aguilera
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | | | - Sung-Bau Lee
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark Master Program for Clinical Pharmacogenomics and Pharmacoproteomics, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Xiaobei Zhao
- Bioinformatics Centre Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Constance Alabert
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Jens V Johansen
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Eric Paquet
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Axis-CHU de Québec Research Center, Quebec City, QC, Canada
| | - Xiang-Jiao Yang
- Department of Medicine, McGill University Health Center, Montréal, QC, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Axis-CHU de Québec Research Center, Quebec City, QC, Canada
| | - Anja Groth
- Biotech Research and Innovation Centre (BRIC) and Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark
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43
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Managing Single-Stranded DNA during Replication Stress in Fission Yeast. Biomolecules 2015; 5:2123-39. [PMID: 26393661 PMCID: PMC4598791 DOI: 10.3390/biom5032123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 01/27/2023] Open
Abstract
Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts) mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron) causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.
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Dungrawala H, Rose KL, Bhat KP, Mohni KN, Glick GG, Couch FB, Cortez D. The Replication Checkpoint Prevents Two Types of Fork Collapse without Regulating Replisome Stability. Mol Cell 2015; 59:998-1010. [PMID: 26365379 DOI: 10.1016/j.molcel.2015.07.030] [Citation(s) in RCA: 265] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/17/2015] [Accepted: 07/28/2015] [Indexed: 02/06/2023]
Abstract
The ATR replication checkpoint ensures that stalled forks remain stable when replisome movement is impeded. Using an improved iPOND protocol combined with SILAC mass spectrometry, we characterized human replisome dynamics in response to fork stalling. Our data provide a quantitative picture of the replisome and replication stress response proteomes in 32 experimental conditions. Importantly, rather than stabilize the replisome, the checkpoint prevents two distinct types of fork collapse. Unsupervised hierarchical clustering of protein abundance on nascent DNA is sufficient to identify protein complexes and place newly identified replisome-associated proteins into functional pathways. As an example, we demonstrate that ZNF644 complexes with the G9a/GLP methyltransferase at replication forks and is needed to prevent replication-associated DNA damage. Our data reveal how the replication checkpoint preserves genome integrity, provide insights into the mechanism of action of ATR inhibitors, and will be a useful resource for replication, DNA repair, and chromatin investigators.
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Affiliation(s)
- Huzefa Dungrawala
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kristie L Rose
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kamakoti P Bhat
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kareem N Mohni
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gloria G Glick
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Frank B Couch
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Butin-Israeli V, Adam SA, Jain N, Otte GL, Neems D, Wiesmüller L, Berger SL, Goldman RD. Role of lamin b1 in chromatin instability. Mol Cell Biol 2015; 35:884-98. [PMID: 25535332 PMCID: PMC4323489 DOI: 10.1128/mcb.01145-14] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/01/2014] [Accepted: 12/18/2014] [Indexed: 01/14/2023] Open
Abstract
Nuclear lamins play important roles in the organization and structure of the nucleus; however, the specific mechanisms linking lamin structure to nuclear functions are poorly defined. We demonstrate that reducing nuclear lamin B1 expression by short hairpin RNA-mediated silencing in cancer cell lines to approximately 50% of normal levels causes a delay in the cell cycle and accumulation of cells in early S phase. The S phase delay appears to be due to the stalling and collapse of replication forks. The double-strand DNA breaks resulting from replication fork collapse were inefficiently repaired, causing persistent DNA damage signaling and the assembly of extensive repair foci on chromatin. The expression of multiple factors involved in DNA replication and repair by both nonhomologous end joining and homologous repair is misregulated when lamin B1 levels are reduced. We further demonstrate that lamin B1 interacts directly with the promoters of some genes associated with DNA damage response and repair, including BRCA1 and RAD51. Taken together, the results suggest that the maintenance of lamin B1 levels is required for DNA replication and repair through regulation of the expression of key factors involved in these essential nuclear functions.
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Affiliation(s)
- Veronika Butin-Israeli
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nikhil Jain
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gabriel L Otte
- Epigenetics Program, Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Daniel Neems
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Shelly L Berger
- Epigenetics Program, Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Franchitto A, Pichierri P. Replication fork recovery and regulation of common fragile sites stability. Cell Mol Life Sci 2014; 71:4507-17. [PMID: 25216703 PMCID: PMC11113654 DOI: 10.1007/s00018-014-1718-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
The acquisition of genomic instability is a triggering factor in cancer development, and common fragile sites (CFS) are the preferential target of chromosomal instability under conditions of replicative stress in the human genome. Although the mechanisms leading to CFS expression and the cellular factors required to suppress CFS instability remain largely undefined, it is clear that DNA becomes more susceptible to breakage when replication is impaired. The models proposed so far to explain how CFS instability arises imply that replication fork progression along these regions is perturbed due to intrinsic features of fragile sites and events that directly affect DNA replication. The observation that proteins implicated in the safe recovery of stalled forks or in engaging recombination at collapsed forks increase CFS expression when downregulated or mutated suggests that the stabilization and recovery of perturbed replication forks are crucial to guarantee CFS integrity.
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Affiliation(s)
- Annapaola Franchitto
- Section of Molecular Epidemiology, Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy,
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Xue L, Furusawa Y, Okayasu R, Miura M, Cui X, Liu C, Hirayama R, Matsumoto Y, Yajima H, Yu D. The complexity of DNA double strand break is a crucial factor for activating ATR signaling pathway for G2/M checkpoint regulation regardless of ATM function. DNA Repair (Amst) 2014; 25:72-83. [PMID: 25497328 DOI: 10.1016/j.dnarep.2014.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 11/17/2022]
Abstract
DNA double strand break (DSB) repair pathway choice following ionizing radiation (IR) is currently an appealing research topic, which is still largely unclear. Our recent paper indicated that the complexity of DSBs is a critical factor that enhances DNA end resection. It has been well accepted that the RPA-coated single strand DNA produced by resection is a signaling structure for ATR activation. Therefore, taking advantage of high linear energy transfer (LET) radiation to effectively produce complex DSBs, we investigated how the complexity of DSB influences the function of ATR pathway on the G2/M checkpoint regulation. Human skin fibroblast cells with or without ATM were irradiated with X rays or heavy ion particles, and dual-parameter flow cytometry was used to quantitatively assess the mitotic entry at early period post radiation by detecting the cells positive for phosphor histone H3. In ATM-deficient cells, ATR pathway played a pivotal role and functioned in a dose- and LET-dependent way to regulate the early G2/M arrest even as low as 0.2Gy for heavy ion radiation, which indicated that ATR pathway could be rapidly activated and functioned in an ATM-independent, but DSB complexity-dependent manner following exposure to IR. Furthermore, ATR pathway also functioned more efficiently in ATM-proficient cells to block G2 to M transition at early period of particle radiation exposure. Accordingly, in contrast to ATM inhibitor, ATR inhibitor had a more effective radiosensitizing effect on survival fraction following heavy ion beams as compared with X ray radiation. Taken together, our results reveal that the complexity of DSBs is a crucial factor for the activation of ATR pathway for G2/M checkpoint regulation, and ATM-dependent end resection is not essential for the activation.
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Affiliation(s)
- Lian Xue
- School of Public Health, Medical College of Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Yoshiya Furusawa
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Ryuichi Okayasu
- International Open Laboratory, National Institute of Radiological Sciences, Chiba, Japan
| | - Masahiko Miura
- Oral Radiation Oncology, Department of Oral Restitution, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Xing Cui
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Cuihua Liu
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Ryoichi Hirayama
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoshitaka Matsumoto
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
| | - Hirohiko Yajima
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan.
| | - Dong Yu
- School of Radiological Medicine and Protection, Medical College of Soochow University, Suzhou, China.
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Rudd SG, Bianchi J, Doherty AJ. PrimPol-A new polymerase on the block. Mol Cell Oncol 2014; 1:e960754. [PMID: 27308331 PMCID: PMC4905188 DOI: 10.4161/23723548.2014.960754] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/22/2014] [Accepted: 07/25/2014] [Indexed: 12/27/2022]
Abstract
The DNA-directed primase-polymerase PrimPol of the archaeo-eukaryotic primase superfamily represents an ancient solution to the many problems faced during genome duplication. This versatile enzyme is capable of initiating de novo DNA/RNA synthesis, DNA chain elongation, and has the capacity to bypass modifications that stall the replisome by trans-lesion synthesis or origin-independent re-priming, thus allowing discontinuous synthesis of the leading strand. Recent studies have shown that PrimPol is an important new player in replication fork progression in eukaryotic cells; this review summarizes our current understanding of PrimPol and highlights important questions that remain to be addressed.
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Affiliation(s)
- Sean G Rudd
- Genome Damage and Stability Center; University of Sussex ; Brighton, UK
| | - Julie Bianchi
- Present address: Department of Oncology-Pathology; Cancer Center Karolinska; Karolinska Institutet ; Stockholm, Sweden
| | - Aidan J Doherty
- Genome Damage and Stability Center; University of Sussex ; Brighton, UK
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González Besteiro MA, Gottifredi V. The fork and the kinase: a DNA replication tale from a CHK1 perspective. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:168-80. [PMID: 25795119 DOI: 10.1016/j.mrrev.2014.10.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 10/07/2014] [Accepted: 10/10/2014] [Indexed: 11/30/2022]
Abstract
Replication fork progression is being continuously hampered by exogenously introduced and naturally occurring DNA lesions and other physical obstacles. Checkpoint kinase 1 (Chk1) is activated at replication forks that encounter damaged DNA. Subsequently, Chk1 inhibits the initiation of new replication factories and stimulates the firing of dormant origins (those in the vicinity of stalled forks). Chk1 also avoids fork collapse into DSBs (double strand breaks) and promotes fork elongation. At the molecular level, the current model considers stalled forks as the site of Chk1 activation and the nucleoplasm as the location where Chk1 phosphorylates target proteins. This model certainly serves to explain how Chk1 modulates origin firing, but how Chk1 controls the fate of stalled forks is less clear. Interestingly, recent reports demonstrating that Chk1 phosphorylates chromatin-bound proteins and even holds kinase-independent functions might shed light on how Chk1 contributes to the elongation of damaged DNA. Indeed, such findings have unveiled a puzzling connection between Chk1 and DNA lesion bypass, which might be central to promoting fork elongation and checkpoint attenuation. In summary, Chk1 is a multifaceted and versatile signaling factor that acts at ongoing forks and replication origins to determine the extent and quality of the cellular response to replication stress.
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Affiliation(s)
- Marina A González Besteiro
- Cell Cycle and Genomic Stability Laboratory, Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| | - Vanesa Gottifredi
- Cell Cycle and Genomic Stability Laboratory, Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina.
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50
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Molecular mechanisms of DNA replication checkpoint activation. Genes (Basel) 2014; 5:147-75. [PMID: 24705291 PMCID: PMC3978517 DOI: 10.3390/genes5010147] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 01/27/2023] Open
Abstract
The major challenge of the cell cycle is to deliver an intact, and fully duplicated, genetic material to the daughter cells. To this end, progression of DNA synthesis is monitored by a feedback mechanism known as replication checkpoint that is untimely linked to DNA replication. This signaling pathway ensures coordination of DNA synthesis with cell cycle progression. Failure to activate this checkpoint in response to perturbation of DNA synthesis (replication stress) results in forced cell division leading to chromosome fragmentation, aneuploidy, and genomic instability. In this review, we will describe current knowledge of the molecular determinants of the DNA replication checkpoint in eukaryotic cells and discuss a model of activation of this signaling pathway crucial for maintenance of genomic stability.
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