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Bainbridge LJ, Daigaku Y. Bulk synthesis and beyond: The roles of eukaryotic replicative DNA polymerases. DNA Repair (Amst) 2024; 141:103740. [PMID: 39096696 DOI: 10.1016/j.dnarep.2024.103740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/27/2024] [Accepted: 07/28/2024] [Indexed: 08/05/2024]
Abstract
An organism's genomic DNA must be accurately duplicated during each cell cycle. DNA synthesis is catalysed by DNA polymerase enzymes, which extend nucleotide polymers in a 5' to 3' direction. This inherent directionality necessitates that one strand is synthesised forwards (leading), while the other is synthesised backwards discontinuously (lagging) to couple synthesis to the unwinding of duplex DNA. Eukaryotic cells possess many diverse polymerases that coordinate to replicate DNA, with the three main replicative polymerases being Pol α, Pol δ and Pol ε. Studies conducted in yeasts and human cells utilising mutant polymerases that incorporate molecular signatures into nascent DNA implicate Pol ε in leading strand synthesis and Pol α and Pol δ in lagging strand replication. Recent structural insights have revealed how the spatial organization of these enzymes around the core helicase facilitates their strand-specific roles. However, various challenging situations during replication require flexibility in the usage of these enzymes, such as during replication initiation or encounters with replication-blocking adducts. This review summarises the roles of the replicative polymerases in bulk DNA replication and explores their flexible and dynamic deployment to complete genome replication. We also examine how polymerase usage patterns can inform our understanding of global replication dynamics by revealing replication fork directionality to identify regions of replication initiation and termination.
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Affiliation(s)
- Lewis J Bainbridge
- Cancer Genome Dynamics Project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yasukazu Daigaku
- Cancer Genome Dynamics Project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
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2
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Ouyang Y, Al-Amodi A, Tehseen M, Alhudhali L, Shirbini A, Takahashi M, Raducanu VS, Yi G, Danazumi A, De Biasio A, Hamdan S. Single-molecule characterization of SV40 replisome and novel factors: human FPC and Mcm10. Nucleic Acids Res 2024; 52:8880-8896. [PMID: 38967018 PMCID: PMC11347169 DOI: 10.1093/nar/gkae565] [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: 08/27/2023] [Revised: 06/06/2024] [Accepted: 06/18/2024] [Indexed: 07/06/2024] Open
Abstract
The simian virus 40 (SV40) replisome only encodes for its helicase; large T-antigen (L-Tag), while relying on the host for the remaining proteins, making it an intriguing model system. Despite being one of the earliest reconstituted eukaryotic systems, the interactions coordinating its activities and the identification of new factors remain largely unexplored. Herein, we in vitro reconstituted the SV40 replisome activities at the single-molecule level, including DNA unwinding by L-Tag and the single-stranded DNA-binding protein Replication Protein A (RPA), primer extension by DNA polymerase δ, and their concerted leading-strand synthesis. We show that RPA stimulates the processivity of L-Tag without altering its rate and that DNA polymerase δ forms a stable complex with L-Tag during leading-strand synthesis. Furthermore, similar to human and budding yeast Cdc45-MCM-GINS helicase, L-Tag uses the fork protection complex (FPC) and the mini-chromosome maintenance protein 10 (Mcm10) during synthesis. Hereby, we demonstrate that FPC increases this rate, and both FPC and Mcm10 increase the processivity by stabilizing stalled replisomes and increasing their chances of restarting synthesis. The detailed kinetics and novel factors of the SV40 replisome establish it as a closer mimic of the host replisome and expand its application as a model replication system.
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Affiliation(s)
- Yujing Ouyang
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Amani Al-Amodi
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Muhammad Tehseen
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Lubna Alhudhali
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Afnan Shirbini
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Masateru Takahashi
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Vlad-Stefan Raducanu
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Gang Yi
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Ammar Usman Danazumi
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Alfredo De Biasio
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Samir M Hamdan
- Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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3
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Bugallo A, Segurado M. Unraveling the complexity of asymmetric DNA replication: Advancements in ribonucleotide mapping techniques and beyond. Genomics 2024; 116:110908. [PMID: 39106913 DOI: 10.1016/j.ygeno.2024.110908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 07/18/2024] [Accepted: 07/31/2024] [Indexed: 08/09/2024]
Abstract
DNA replication is a fundamental process for cell proliferation, governed by intricate mechanisms involving leading and lagging strand synthesis. In eukaryotes, canonical DNA replication occurs during the S phase of the cell cycle, facilitated by various components of the replicative machinery at sites known as replication origins. Leading and lagging strands exhibit distinct replication dynamics, with leading strand replication being relatively straightforward compared to the complex synthesis of lagging strands involving Okazaki fragment maturation. Central to DNA synthesis are DNA polymerases, with Polα, Polε, and Polδ playing pivotal roles, each specializing in specific tasks during replication. Notably, leading and lagging strands are replicated by different polymerases, contributing to the division of labor in DNA replication. Understanding the enzymology of asymmetric DNA replication has been challenging, with methods relying on ribonucleotide incorporation and next-generation sequencing techniques offering comprehensive insights. These methodologies, such as HydEn-seq, PU-seq, ribose-seq, and emRiboSeq, offer insights into polymerase activity and strand synthesis, aiding in understanding DNA replication dynamics. Recent advancements include novel conditional mutants for ribonucleotide excision repair, enzymatic cleavage alternatives, and unified pipelines for data analysis. Further developments in adapting techniques to different organisms, studying non-canonical polymerases, and exploring new sequencing platforms hold promise for expanding our understanding of DNA replication dynamics. Integrating strand-specific information into single-cell studies could offer novel insights into enzymology, opening avenues for future research and applications in repair and replication biology.
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Affiliation(s)
- Alberto Bugallo
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Mónica Segurado
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain; Departamento de Microbiología y Genética (USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain.
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4
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Norris J, Rogers L, Pytko K, Dannenberg R, Perreault S, Kaushik V, Kuppa S, Antony E, Hedglin M. Replication protein A dynamically re-organizes on primer/template junctions to permit DNA polymerase δ holoenzyme assembly and initiation of DNA synthesis. Nucleic Acids Res 2024; 52:7650-7664. [PMID: 38842913 PMCID: PMC11260492 DOI: 10.1093/nar/gkae475] [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: 08/28/2023] [Revised: 05/03/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024] Open
Abstract
DNA polymerase δ (pol δ) holoenzymes, comprised of pol δ and the processivity sliding clamp, PCNA, carry out DNA synthesis during lagging strand replication, initiation of leading strand replication, and the major DNA damage repair and tolerance pathways. Pol δ holoenzymes are assembled at primer/template (P/T) junctions and initiate DNA synthesis in a stepwise process involving the major single strand DNA (ssDNA)-binding protein complex, RPA, the processivity sliding clamp loader, RFC, PCNA and pol δ. During this process, the interactions of RPA, RFC and pol δ with a P/T junction all significantly overlap. A burning issue that has yet to be resolved is how these overlapping interactions are accommodated during this process. To address this, we design and utilize novel, ensemble FRET assays that continuously monitor the interactions of RPA, RFC, PCNA and pol δ with DNA as pol δ holoenzymes are assembled and initiate DNA synthesis. Results from the present study reveal that RPA remains engaged with P/T junctions throughout this process and the RPA•DNA complexes dynamically re-organize to allow successive binding of RFC and pol δ. These results have broad implications as they highlight and distinguish the functional consequences of dynamic RPA•DNA interactions in RPA-dependent DNA metabolic processes.
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Affiliation(s)
- Jessica L Norris
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Lindsey O Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kara G Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Rachel L Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Samuel Perreault
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Vikas Kaushik
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis, MO 63104, USA
| | - Sahiti Kuppa
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis, MO 63104, USA
| | - Edwin Antony
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis, MO 63104, USA
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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5
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Sawant A, Shi F, Lopes EC, Hu Z, Abdelfattah S, Baul J, Powers J, Hinrichs CS, Rabinowitz JD, Chan CS, Lattime EC, Ganesan S, White E. Immune Checkpoint Blockade Delays Cancer and Extends Survival in Murine DNA Polymerase Mutator Syndromes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.10.597960. [PMID: 38915517 PMCID: PMC11195045 DOI: 10.1101/2024.06.10.597960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Mutations in polymerases Pold1 and Pole exonuclease domains in humans are associated with increased cancer incidence, elevated tumor mutation burden (TMB) and response to immune checkpoint blockade (ICB). Although ICB is approved for treatment of several cancers, not all tumors with elevated TMB respond. Here we generated Pold1 and Pole proofreading mutator mice and show that ICB treatment of mice with high TMB tumors did not improve survival as only a subset of tumors responded. Similarly, introducing the mutator alleles into mice with Kras/p53 lung cancer did not improve survival, however, passaging mutator tumor cells in vitro without immune editing caused rejection in immune-competent hosts, demonstrating the efficiency by which cells with antigenic mutations are eliminated. Finally, ICB treatment of mutator mice earlier, before observable tumors delayed cancer onset, improved survival, and selected for tumors without aneuploidy, suggesting the use of ICB in individuals at high risk for cancer prevention. Highlights Germline somatic and conditional Pold1 and Pole exonuclease domain mutations in mice produce a mutator phenotype. Spontaneous cancers arise in mutator mice that have genomic features comparable to human tumors with these mutations.ICB treatment of mutator mice with tumors did not improve survival as only a subset of tumors respond. Introduction of the mutator alleles into an autochthonous mouse lung cancer model also did not produce immunogenic tumors, whereas passaging mutator tumor cells in vitro caused immune rejection indicating efficient selection against antigenic mutations in vivo . Prophylactic ICB treatment delayed cancer onset, improved survival, and selected for tumors with no aneuploidy.
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6
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Pytko KG, Dannenberg RL, Eckert KA, Hedglin M. Replication of [AT/TA] 25 Microsatellite Sequences by Human DNA Polymerase δ Holoenzymes Is Dependent on dNTP and RPA Levels. Biochemistry 2024; 63:969-983. [PMID: 38623046 DOI: 10.1021/acs.biochem.4c00006] [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] [Indexed: 04/17/2024]
Abstract
Fragile sites are unstable genomic regions that are prone to breakage during stressed DNA replication. Several common fragile sites (CFS) contain A+T-rich regions including perfect [AT/TA] microsatellite repeats that may collapse into hairpins when in single-stranded DNA (ssDNA) form and coincide with chromosomal hotspots for breakage and rearrangements. While many factors contribute to CFS instability, evidence exists for replication stalling within [AT/TA] microsatellite repeats. Currently, it is unknown how stress causes replication stalling within [AT/TA] microsatellite repeats. To investigate this, we utilized FRET to characterize the structures of [AT/TA]25 sequences and also reconstituted lagging strand replication to characterize the progression of pol δ holoenzymes through A+T-rich sequences. The results indicate that [AT/TA]25 sequences adopt hairpins that are unwound by the major ssDNA-binding complex, RPA, and the progression of pol δ holoenzymes through A+T-rich sequences saturated with RPA is dependent on the template sequence and dNTP concentration. Importantly, the effects of RPA on the replication of [AT/TA]25 sequences are dependent on dNTP concentration, whereas the effects of RPA on the replication of A+T-rich, nonstructure-forming sequences are independent of dNTP concentration. Collectively, these results reveal complexities in lagging strand replication and provide novel insights into how [AT/TA] microsatellite repeats contribute to genome instability.
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Affiliation(s)
- Kara G Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Rachel L Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Kristin A Eckert
- Department of Pathology and Laboratory Medicine, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, United States
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
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7
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Keyhanian K, Han L, Howitt BE, Longacre T. Specific Pathology Features Enrich Selection of Endometrial Carcinomas for POLE Testing. Am J Surg Pathol 2024; 48:292-301. [PMID: 38062789 DOI: 10.1097/pas.0000000000002165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Identification of ultramutated/ POLE -mutated endometrial carcinomas ( POLEM ECs) has important implications given its association with better prognosis. However, POLE mutation testing is not widely available. Our objective was to evaluate POLEM ECs versus POLE wild-type ( POLEWT ) ECs, within a cohort of consultation cases with features suggestive of an ultramutated phenotype. Consultation cases of EC that had undergone POLE hotspot mutation testing over a 3.5-year period were included. Tumor morphology and immunohistochemistry were reviewed for both groups. Chi-square test and t test were used for statistical analysis. Of 25 consultation cases, 12 harbored a POLE mutation (48%) and 13 were wild-type (52%). Patients with POLEM ECs were younger (59 vs. 71.3 y; P =0.01). Ambiguous histomorphology (5/12 vs. 1/13; P =0.04) and the presence of more than rare bizarre nuclei (8/12 vs. 2/12; P =0.01) differed significantly between POLEM and POLEWT ECs, respectively. In the POLEM group, one case (1/12) demonstrated PMS2 loss, and one (1/12) showed subclonal MLH1/PMS2 loss. Among POLEWT ECs, 3/13 (23%) showed MLH1/PMS2 loss. p53 was subclonally overexpressed in 4/10 POLEM and 1/13 POLEWT cases ( P =0.06). Mutant p53 patterns were seen in 1/10 POLEM versus 6/13 of POLEWT ECs, respectively ( P =0.06). Within our cohort, the specificity of ambiguous histomorphology, bizarre nuclei, subclonal biomarker expression, and marked tumor-infiltrating lymphocytes for POLEM EC was 83%, 80%, 80%, and 71%, respectively. Where universal POLE testing is not available, these data suggest that morphologic screening (particularly ambiguous histomorphology and the presence of more than rare bizarre nuclei) can be useful for selective enrichment of ECs for POLE testing.
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Affiliation(s)
- Kianoosh Keyhanian
- Department of Pathology and Laboratory Medicine, University of Ottawa/The Ottawa Hospital, Ottawa, ON, Canada
| | - Lucy Han
- Department of Pathology, California Pacific Medical Center, San Francisco
| | | | - Teri Longacre
- Department of Pathology, Stanford University, Stanford, CA
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8
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Selves J, de Castro E Gloria H, Brunac AC, Saffi J, Guimbaud R, Brousset P, Hoffmann JS. Exploring the basis of heterogeneity of cancer aggressiveness among the mutated POLE variants. Life Sci Alliance 2024; 7:e202302290. [PMID: 37891003 PMCID: PMC10610022 DOI: 10.26508/lsa.202302290] [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: 07/25/2023] [Revised: 10/04/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Germline pathogenic variants in the exonuclease domain of the replicative DNA polymerase Pol ε encoded by the POLE gene, predispose essentially to colorectal and endometrial tumors by inducing an ultramutator phenotype. It is still unclear whether all the POLE alterations influence similar strength tumorigenesis, immune microenvironment, and treatment response. In this review, we summarize the current understanding of the mechanisms and consequences of POLE mutations in human malignancies; we highlight the heterogeneity of mutation rate and cancer aggressiveness among POLE variants, propose some mechanistic basis underlining such heterogeneity, and discuss novel considerations for the choice and efficacy of therapies of POLE tumors.
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Affiliation(s)
- Janick Selves
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
| | - Helena de Castro E Gloria
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - Anne-Cécile Brunac
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
| | - Jenifer Saffi
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - Rosine Guimbaud
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
- Department of Digestive Oncology, Centre Hospitalier Universitaire (CHU), Toulouse, France
- Department of Digestive Surgery, Centre Hospitalier Universitaire (CHU), Toulouse, France
| | - Pierre Brousset
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III Paul Sabatier, INSERM, CRCT, Toulouse, France
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
| | - Jean-Sébastien Hoffmann
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse; Centre Hospitalier Universitaire (CHU), Toulouse, France
- Laboratoire d'Excellence Toulouse Cancer (TOUCAN), Toulouse, France
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Parkash V, Kulkarni Y, Bylund GO, Osterman P, Kamerlin S, Johansson E. A sensor complements the steric gate when DNA polymerase ϵ discriminates ribonucleotides. Nucleic Acids Res 2023; 51:11225-11238. [PMID: 37819038 PMCID: PMC10639073 DOI: 10.1093/nar/gkad817] [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: 07/01/2023] [Revised: 09/01/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
The cellular imbalance between high concentrations of ribonucleotides (NTPs) and low concentrations of deoxyribonucleotides (dNTPs), is challenging for DNA polymerases when building DNA from dNTPs. It is currently believed that DNA polymerases discriminate against NTPs through a steric gate model involving a clash between a tyrosine and the 2'-hydroxyl of the ribonucleotide in the polymerase active site in B-family DNA polymerases. With the help of crystal structures of a B-family polymerase with a UTP or CTP in the active site, molecular dynamics simulations, biochemical assays and yeast genetics, we have identified a mechanism by which the finger domain of the polymerase sense NTPs in the polymerase active site. In contrast to the previously proposed polar filter, our experiments suggest that the amino acid residue in the finger domain senses ribonucleotides by steric hindrance. Furthermore, our results demonstrate that the steric gate in the palm domain and the sensor in the finger domain are both important when discriminating NTPs. Structural comparisons reveal that the sensor residue is conserved among B-family polymerases and we hypothesize that a sensor in the finger domain should be considered in all types of DNA polymerases.
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Affiliation(s)
- Vimal Parkash
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 90187, Sweden
| | - Yashraj Kulkarni
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala S-751 23, Sweden
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Göran O Bylund
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 90187, Sweden
| | - Pia Osterman
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 90187, Sweden
| | - Shina Caroline Lynn Kamerlin
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala S-751 23, Sweden
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA 30332-0400, USA
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 90187, Sweden
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Pytko KG, Dannenberg RL, Eckert KA, Hedglin M. Replication of [AT/TA] 25 microsatellite sequences by human DNA polymerase δ holoenzymes is dependent on dNTP and RPA levels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566133. [PMID: 37986888 PMCID: PMC10659299 DOI: 10.1101/2023.11.07.566133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Difficult-to-Replicate Sequences (DiToRS) are natural impediments in the human genome that inhibit DNA replication under endogenous replication. Some of the most widely-studied DiToRS are A+T-rich, high "flexibility regions," including long stretches of perfect [AT/TA] microsatellite repeats that have the potential to collapse into hairpin structures when in single-stranded DNA (ssDNA) form and are sites of recurrent structural variation and double-stranded DNA (dsDNA) breaks. Currently, it is unclear how these flexibility regions impact DNA replication, greatly limiting our fundamental understanding of human genome stability. To investigate replication through flexibility regions, we utilized FRET to characterize the effects of the major ssDNA-binding complex, RPA, on the structure of perfect [AT/TA]25 microsatellite repeats and also re-constituted human lagging strand replication to quantitatively characterize initial encounters of pol δ holoenzymes with A+T-rich DNA template sequences. The results indicate that [AT/TA]25 sequences adopt hairpin structures that are unwound by RPA and pol δ holoenzymes support dNTP incorporation through the [AT/TA]25 sequences as well as an A+T-rich, non-structure forming sequence. Furthermore, the extent of dNTP incorporation is dependent on the sequence of the DNA template and the concentration of dNTPs. Importantly, the effects of RPA on the replication of [AT/TA]25 sequences are dependent on the concentration of dNTPs, whereas the effects of RPA on the replication of an A+T-rich, non-structure forming sequence are independent of dNTP concentration. Collectively, these results reveal complexities in lagging strand replication and provide novel insights into how flexibility regions contribute to genome instability.
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Affiliation(s)
- Kara G. Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Rachel L. Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Kristin A. Eckert
- Department of Pathology and Laboratory Medicine, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
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11
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Dmowski M, Makiela-Dzbenska K, Sharma S, Chabes A, Fijalkowska IJ. Impairment of the non-catalytic subunit Dpb2 of DNA Pol ɛ results in increased involvement of Pol δ on the leading strand. DNA Repair (Amst) 2023; 129:103541. [PMID: 37481989 DOI: 10.1016/j.dnarep.2023.103541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/29/2023] [Accepted: 07/05/2023] [Indexed: 07/25/2023]
Abstract
The generally accepted model assumes that leading strand synthesis is performed by Pol ε, while lagging-strand synthesis is catalyzed by Pol δ. Pol ε has been shown to target the leading strand by interacting with the CMG helicase [Cdc45 Mcm2-7 GINS(Psf1-3, Sld5)]. Proper functioning of the CMG-Pol ɛ, the helicase-polymerase complex is essential for its progression and the fidelity of DNA replication. Dpb2p, the essential non-catalytic subunit of Pol ε plays a key role in maintaining the correct architecture of the replisome by acting as a link between Pol ε and the CMG complex. Using a temperature-sensitive dpb2-100 mutant previously isolated in our laboratory, and a genetic system which takes advantage of a distinct mutational signature of the Pol δ-L612M variant which allows detection of the involvement of Pol δ in the replication of particular DNA strands we show that in yeast cells with an impaired Dpb2 subunit, the contribution of Pol δ to the replication of the leading strand is significantly increased.
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Affiliation(s)
- Michal Dmowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
| | - Karolina Makiela-Dzbenska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Iwona J Fijalkowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
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12
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Norris JL, Rogers LO, Pytko KG, Dannenberg RL, Perreault S, Kaushik V, Kuppa S, Antony E, Hedglin M. Interplay of macromolecular interactions during assembly of human DNA polymerase δ holoenzymes and initiation of DNA synthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.539896. [PMID: 37215012 PMCID: PMC10197535 DOI: 10.1101/2023.05.09.539896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In humans, DNA polymerase δ (Pol δ) holoenzymes, comprised of Pol δ and the processivity sliding clamp, proliferating cell nuclear antigen (PCNA), carry out DNA synthesis during lagging strand DNA replication, initiation of leading strand DNA replication, and the major DNA damage repair and tolerance pathways. Pol δ holoenzymes are assembled at primer/template (P/T) junctions and initiate DNA synthesis in a coordinated process involving the major single strand DNA-binding protein complex, replication protein A (RPA), the processivity sliding clamp loader, replication factor C (RFC), PCNA, and Pol δ. Each of these factors interact uniquely with a P/T junction and most directly engage one another. Currently, the interplay between these macromolecular interactions is largely unknown. In the present study, novel Förster Resonance Energy Transfer (FRET) assays reveal that dynamic interactions of RPA with a P/T junction during assembly of a Pol δ holoenzyme and initiation of DNA synthesis maintain RPA at a P/T junction and accommodate RFC, PCNA, and Pol δ, maximizing the efficiency of each process. Collectively, these studies significantly advance our understanding of human DNA replication and DNA repair.
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Affiliation(s)
- Jessica L. Norris
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Lindsey O. Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Kara G. Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Rachel L. Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Samuel Perreault
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Vikas Kaushik
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis MO, 63104
| | - Sahiti Kuppa
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis MO, 63104
| | - Edwin Antony
- The Saint Louis University School of Medicine, Department of Biochemistry and Molecular Biology, St. Louis MO, 63104
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
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13
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Koyanagi E, Kakimoto Y, Minamisawa T, Yoshifuji F, Natsume T, Higashitani A, Ogi T, Carr AM, Kanemaki MT, Daigaku Y. Global landscape of replicative DNA polymerase usage in the human genome. Nat Commun 2022; 13:7221. [PMID: 36434012 PMCID: PMC9700718 DOI: 10.1038/s41467-022-34929-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022] Open
Abstract
The division of labour among DNA polymerase underlies the accuracy and efficiency of replication. However, the roles of replicative polymerases have not been directly established in human cells. We developed polymerase usage sequencing (Pu-seq) in HCT116 cells and mapped Polε and Polα usage genome wide. The polymerase usage profiles show Polε synthesises the leading strand and Polα contributes mainly to lagging strand synthesis. Combining the Polε and Polα profiles, we accurately predict the genome-wide pattern of fork directionality plus zones of replication initiation and termination. We confirm that transcriptional activity contributes to the pattern of initiation and termination and, by separately analysing the effect of transcription on co-directional and converging forks, demonstrate that coupled DNA synthesis of leading and lagging strands is compromised by transcription in both co-directional and convergent forks. Polymerase uncoupling is particularly evident in the vicinity of large genes, including the two most unstable common fragile sites, FRA3B and FRA3D, thus linking transcription-induced polymerase uncoupling to chromosomal instability. Together, our result demonstrated that Pu-seq in human cells provides a powerful and straightforward methodology to explore DNA polymerase usage and replication fork dynamics.
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Affiliation(s)
- Eri Koyanagi
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Yoko Kakimoto
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Tamiko Minamisawa
- grid.410807.a0000 0001 0037 4131Cancer Genome Dynamics project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Fumiya Yoshifuji
- grid.69566.3a0000 0001 2248 6943Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Toyoaki Natsume
- grid.418987.b0000 0004 1764 2181National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan ,grid.275033.00000 0004 1763 208XDepartment of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan ,grid.272456.00000 0000 9343 3630Present Address: Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Atsushi Higashitani
- grid.69566.3a0000 0001 2248 6943Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Tomoo Ogi
- grid.27476.300000 0001 0943 978XResearch Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Antony M. Carr
- grid.12082.390000 0004 1936 7590Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ UK
| | - Masato T. Kanemaki
- grid.418987.b0000 0004 1764 2181National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan ,grid.275033.00000 0004 1763 208XDepartment of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yasukazu Daigaku
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan ,grid.410807.a0000 0001 0037 4131Cancer Genome Dynamics project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
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14
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Williams JS, Kunkel TA. Ribonucleotide Incorporation by Eukaryotic B-family Replicases and Its Implications for Genome Stability. Annu Rev Biochem 2022; 91:133-155. [PMID: 35287470 DOI: 10.1146/annurev-biochem-032620-110354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Our current view of how DNA-based genomes are efficiently and accurately replicated continues to evolve as new details emerge on the presence of ribonucleotides in DNA. Ribonucleotides are incorporated during eukaryotic DNA replication at rates that make them the most common noncanonical nucleotide placed into the nuclear genome, they are efficiently repaired, and their removal impacts genome integrity. This review focuses on three aspects of this subject: the incorporation of ribonucleotides into the eukaryotic nuclear genome during replication by B-family DNA replicases, how these ribonucleotides are removed, and the consequences of their presence or removal for genome stability and disease. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Jessica S Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA;
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA;
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15
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Díaz-Talavera A, Montero-Conde C, Leandro-García LJ, Robledo M. PrimPol: A Breakthrough among DNA Replication Enzymes and a Potential New Target for Cancer Therapy. Biomolecules 2022; 12:248. [PMID: 35204749 PMCID: PMC8961649 DOI: 10.3390/biom12020248] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/29/2022] [Accepted: 02/02/2022] [Indexed: 02/01/2023] Open
Abstract
DNA replication can encounter blocking obstacles, leading to replication stress and genome instability. There are several mechanisms for evading this blockade. One mechanism consists of repriming ahead of the obstacles, creating a new starting point; in humans, PrimPol is responsible for carrying out this task. PrimPol is a primase that operates in both the nucleus and mitochondria. In contrast with conventional primases, PrimPol is a DNA primase able to initiate DNA synthesis de novo using deoxynucleotides, discriminating against ribonucleotides. In vitro, PrimPol can act as a DNA primase, elongating primers that PrimPol itself sythesizes, or as translesion synthesis (TLS) DNA polymerase, elongating pre-existing primers across lesions. However, the lack of evidence for PrimPol polymerase activity in vivo suggests that PrimPol only acts as a DNA primase. Here, we provide a comprehensive review of human PrimPol covering its biochemical properties and structure, in vivo function and regulation, and the processes that take place to fill the gap-containing lesion that PrimPol leaves behind. Finally, we explore the available data on human PrimPol expression in different tissues in physiological conditions and its role in cancer.
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Affiliation(s)
- Alberto Díaz-Talavera
- Hereditary Endocrine Cancer Group, Human Cancer Genetics Program, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain; (C.M.-C.); (L.J.L.-G.); (M.R.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - Cristina Montero-Conde
- Hereditary Endocrine Cancer Group, Human Cancer Genetics Program, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain; (C.M.-C.); (L.J.L.-G.); (M.R.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - Luis Javier Leandro-García
- Hereditary Endocrine Cancer Group, Human Cancer Genetics Program, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain; (C.M.-C.); (L.J.L.-G.); (M.R.)
| | - Mercedes Robledo
- Hereditary Endocrine Cancer Group, Human Cancer Genetics Program, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain; (C.M.-C.); (L.J.L.-G.); (M.R.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
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16
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Increased contribution of DNA polymerase delta to the leading strand replication in yeast with an impaired CMG helicase complex. DNA Repair (Amst) 2022; 110:103272. [DOI: 10.1016/j.dnarep.2022.103272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/24/2021] [Accepted: 01/04/2022] [Indexed: 11/19/2022]
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17
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Zhou ZX, Lujan SA, Burkholder AB, St. Charles J, Dahl J, Farrell CE, Williams JS, Kunkel TA. How asymmetric DNA replication achieves symmetrical fidelity. Nat Struct Mol Biol 2021; 28:1020-1028. [PMID: 34887558 PMCID: PMC8815454 DOI: 10.1038/s41594-021-00691-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/22/2021] [Indexed: 11/09/2022]
Abstract
Accurate DNA replication of an undamaged template depends on polymerase selectivity for matched nucleotides, exonucleolytic proofreading of mismatches, and removal of remaining mismatches via DNA mismatch repair (MMR). DNA polymerases (Pols) δ and ε have 3'-5' exonucleases into which mismatches are partitioned for excision in cis (intrinsic proofreading). Here we provide strong evidence that Pol δ can extrinsically proofread mismatches made by itself and those made by Pol ε, independently of both Pol δ's polymerization activity and MMR. Extrinsic proofreading across the genome is remarkably efficient. We report, with unprecedented accuracy, in vivo contributions of nucleotide selectivity, proofreading, and MMR to the fidelity of DNA replication in Saccharomyces cerevisiae. We show that extrinsic proofreading by Pol δ improves and balances the fidelity of the two DNA strands. Together, we depict a comprehensive picture of how nucleotide selectivity, proofreading, and MMR cooperate to achieve high and symmetrical fidelity on the two strands.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Scott A. Lujan
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Adam B. Burkholder
- Integrative Bioinformatics Support Group, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Jordan St. Charles
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Joseph Dahl
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Corinne E. Farrell
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Jessica S. Williams
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
| | - Thomas A. Kunkel
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, North Carolina, USA
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18
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Bainbridge LJ, Teague R, Doherty AJ. Repriming DNA synthesis: an intrinsic restart pathway that maintains efficient genome replication. Nucleic Acids Res 2021; 49:4831-4847. [PMID: 33744934 PMCID: PMC8136793 DOI: 10.1093/nar/gkab176] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 12/25/2022] Open
Abstract
To bypass a diverse range of fork stalling impediments encountered during genome replication, cells possess a variety of DNA damage tolerance (DDT) mechanisms including translesion synthesis, template switching, and fork reversal. These pathways function to bypass obstacles and allow efficient DNA synthesis to be maintained. In addition, lagging strand obstacles can also be circumvented by downstream priming during Okazaki fragment generation, leaving gaps to be filled post-replication. Whether repriming occurs on the leading strand has been intensely debated over the past half-century. Early studies indicated that both DNA strands were synthesised discontinuously. Although later studies suggested that leading strand synthesis was continuous, leading to the preferred semi-discontinuous replication model. However, more recently it has been established that replicative primases can perform leading strand repriming in prokaryotes. An analogous fork restart mechanism has also been identified in most eukaryotes, which possess a specialist primase called PrimPol that conducts repriming downstream of stalling lesions and structures. PrimPol also plays a more general role in maintaining efficient fork progression. Here, we review and discuss the historical evidence and recent discoveries that substantiate repriming as an intrinsic replication restart pathway for maintaining efficient genome duplication across all domains of life.
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Affiliation(s)
- Lewis J Bainbridge
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Rebecca Teague
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
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19
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Zach R, Carr AM. Increased expression of Polδ does not alter the canonical replication program in vivo. Wellcome Open Res 2021; 6:44. [PMID: 33796794 PMCID: PMC7974630 DOI: 10.12688/wellcomeopenres.16600.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2021] [Indexed: 01/08/2023] Open
Abstract
Background: In vitro experiments utilising the reconstituted Saccharomyces cerevisiae eukaryotic replisome indicated that the efficiency of the leading strand replication is impaired by a moderate increase in Polδ concentration. It was hypothesised that the slower rate of the leading strand synthesis characteristic for reactions containing two-fold and four-fold increased concentration of Polδ represented a consequence of a relatively rare event, during which Polδ stochastically outcompeted Polε and, in an inefficient manner, temporarily facilitated extension of the leading strand. Inspired by this observation, we aimed to determine whether similarly increased Polδ levels influence replication dynamics in vivo using the fission yeast Schizosaccharomyces pombe as a model system. Methods: To generate S. pombe strains over-expressing Polδ, we utilised Cre-Lox mediated cassette exchange and integrated one or three extra genomic copies of all four Polδ genes. To estimate expression of respective Polδ genes in Polδ-overexpressing mutants, we measured relative transcript levels of cdc1 + , cdc6 + (or cdc6 L591G ), cdc27 + and cdm1 + by reverse transcription followed by quantitative PCR (RT-qPCR). To assess the impact of Polδ over-expression on cell physiology and replication dynamics, we used standard cell biology techniques and polymerase usage sequencing. Results: We provide an evidence that two-fold and four-fold over-production of Polδ does not significantly alter growth rate, cellular morphology and S-phase duration. Polymerase usage sequencing analysis further indicates that increased Polδ expression does not change activities of Polδ, Polε and Polα at replication initiation sites and across replication termination zones. Additionally, we show that mutants over-expressing Polδ preserve WT-like distribution of replication origin efficiencies. Conclusions: Our experiments do not disprove the existence of opportunistic polymerase switches; however, the data indicate that, if stochastic replacement of Polε for Polδ does occur i n vivo, it represents a rare phenomenon that does not significantly influence canonical replication program.
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Affiliation(s)
- Róbert Zach
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Antony M. Carr
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
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20
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Abstract
The faithful and timely copying of DNA by molecular machines known as replisomes depends on a disparate suite of enzymes and scaffolding factors working together in a highly orchestrated manner. Large, dynamic protein-nucleic acid assemblies that selectively morph between distinct conformations and compositional states underpin this critical cellular process. In this article, we discuss recent progress outlining the physical basis of replisome construction and progression in eukaryotes.
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Affiliation(s)
- Ilan Attali
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA;
| | - Michael R Botchan
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA;
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21
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Zach R, Carr AM. Increased expression of Polδ does not alter the canonical replication program in vivo. Wellcome Open Res 2021; 6:44. [PMID: 33796794 PMCID: PMC7974630 DOI: 10.12688/wellcomeopenres.16600.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2021] [Indexed: 11/20/2022] Open
Abstract
Background: In vitro experiments utilising the reconstituted Saccharomyces cerevisiae eukaryotic replisome indicated that the efficiency of the leading strand replication is impaired by a moderate increase in Polδ concentration. It was hypothesised that the slower rate of the leading strand synthesis characteristic for reactions containing two-fold and four-fold increased concentration of Polδ represented a consequence of a relatively rare event, during which Polδ stochastically outcompeted Polε and, in an inefficient manner, temporarily facilitated extension of the leading strand. Inspired by this observation, we aimed to determine whether similarly increased Polδ levels influence replication dynamics in vivo using the fission yeast Schizosaccharomyces pombe as a model system. Methods: To generate S. pombe strains over-expressing Polδ, we utilised Cre-Lox mediated cassette exchange and integrated one or three extra genomic copies of all four Polδ genes. To estimate expression of respective Polδ genes in Polδ-overexpressing mutants, we measured relative transcript levels of cdc1 + , cdc6 + (or cdc6 L591G ), cdc27 + and cdm1 + by reverse transcription followed by quantitative PCR (RT-qPCR). To assess the impact of Polδ over-expression on cell physiology and replication dynamics, we used standard cell biology techniques and polymerase usage sequencing. Results: We provide an evidence that two-fold and four-fold over-production of Polδ does not significantly alter growth rate, cellular morphology and S-phase duration. Polymerase usage sequencing analysis further indicates that increased Polδ expression does not change activities of Polδ, Polε and Polα at replication initiation sites and across replication termination zones. Additionally, we show that mutants over-expressing Polδ preserve WT-like distribution of replication origin efficiencies. Conclusions: Our experiments do not disprove the existence of opportunistic polymerase switches; however, the data indicate that, if stochastic replacement of Polε for Polδ does occur i n vivo, it represents a rare phenomenon that does not significantly influence canonical replication program.
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Affiliation(s)
- Róbert Zach
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Antony M. Carr
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
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22
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Zhou ZX, Williams JS, Lujan SA, Kunkel TA. Ribonucleotide incorporation into DNA during DNA replication and its consequences. Crit Rev Biochem Mol Biol 2021; 56:109-124. [PMID: 33461360 DOI: 10.1080/10409238.2020.1869175] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ribonucleotides are the most abundant non-canonical nucleotides in the genome. Their vast presence and influence over genome biology is becoming increasingly appreciated. Here we review the recent progress made in understanding their genomic presence, incorporation characteristics and usefulness as biomarkers for polymerase enzymology. We also discuss ribonucleotide processing, the genetic consequences of unrepaired ribonucleotides in DNA and evidence supporting the significance of their transient presence in the nuclear genome.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Jessica S Williams
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Scott A Lujan
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Thomas A Kunkel
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
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23
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Galati MA, Hodel KP, Gams MS, Sudhaman S, Bridge T, Zahurancik WJ, Ungerleider NA, Park VS, Ercan AB, Joksimovic L, Siddiqui I, Siddaway R, Edwards M, de Borja R, Elshaer D, Chung J, Forster VJ, Nunes NM, Aronson M, Wang X, Ramdas J, Seeley A, Sarosiek T, Dunn GP, Byrd JN, Mordechai O, Durno C, Martin A, Shlien A, Bouffet E, Suo Z, Jackson JG, Hawkins CE, Guidos CJ, Pursell ZF, Tabori U. Cancers from Novel Pole-Mutant Mouse Models Provide Insights into Polymerase-Mediated Hypermutagenesis and Immune Checkpoint Blockade. Cancer Res 2020; 80:5606-5618. [PMID: 32938641 PMCID: PMC8218238 DOI: 10.1158/0008-5472.can-20-0624] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/25/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022]
Abstract
POLE mutations are a major cause of hypermutant cancers, yet questions remain regarding mechanisms of tumorigenesis, genotype-phenotype correlation, and therapeutic considerations. In this study, we establish mouse models harboring cancer-associated POLE mutations P286R and S459F, which cause rapid albeit distinct time to cancer initiation in vivo, independent of their exonuclease activity. Mouse and human correlates enabled novel stratification of POLE mutations into three groups based on clinical phenotype and mutagenicity. Cancers driven by these mutations displayed striking resemblance to the human ultrahypermutation and specific signatures. Furthermore, Pole-driven cancers exhibited a continuous and stochastic mutagenesis mechanism, resulting in intertumoral and intratumoral heterogeneity. Checkpoint blockade did not prevent Pole lymphomas, but rather likely promoted lymphomagenesis as observed in humans. These observations provide insights into the carcinogenesis of POLE-driven tumors and valuable information for genetic counseling, surveillance, and immunotherapy for patients. SIGNIFICANCE: Two mouse models of polymerase exonuclease deficiency shed light on mechanisms of mutation accumulation and considerations for immunotherapy.See related commentary by Wisdom and Kirsch p. 5459.
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Affiliation(s)
- Melissa A Galati
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Miki S Gams
- Program in Developmental and Stem Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Sumedha Sudhaman
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Taylor Bridge
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Walter J Zahurancik
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
| | - Nathan A Ungerleider
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Ayse B Ercan
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lazar Joksimovic
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Iram Siddiqui
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Robert Siddaway
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa Edwards
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Richard de Borja
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dana Elshaer
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jiil Chung
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Victoria J Forster
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nuno M Nunes
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melyssa Aronson
- The Familial Gastrointestinal Cancer Registry at the Zane Cohen Centre for Digestive Disease, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Xia Wang
- H Lee Moffitt Cancer Centre and Research Institute, Tampa, Florida
| | - Jagadeesh Ramdas
- Department of Pediatrics, Geisinger Medical Center, Danville, Pennsylvania
| | - Andrea Seeley
- Department of Pediatrics, Geisinger Medical Center, Danville, Pennsylvania
| | | | - Gavin P Dunn
- Department of Neurological Surgery, Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri
| | - Jonathan N Byrd
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Oz Mordechai
- Department of Pediatric Hematology Oncology, Rambam Health Care Campus, Haifa, Israel
| | - Carol Durno
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alberto Martin
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Adam Shlien
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Eric Bouffet
- Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zucai Suo
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
| | - James G Jackson
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Cynthia E Hawkins
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Cynthia J Guidos
- Program in Developmental and Stem Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Uri Tabori
- Program in Genetics and Genome Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
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24
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Zahurancik WJ, Suo Z. Kinetic investigation of the polymerase and exonuclease activities of human DNA polymerase ε holoenzyme. J Biol Chem 2020; 295:17251-17264. [PMID: 33051204 PMCID: PMC7863874 DOI: 10.1074/jbc.ra120.013903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/09/2020] [Indexed: 12/31/2022] Open
Abstract
In eukaryotic DNA replication, DNA polymerase ε (Polε) is responsible for leading strand synthesis, whereas DNA polymerases α and δ synthesize the lagging strand. The human Polε (hPolε) holoenzyme is comprised of the catalytic p261 subunit and the noncatalytic p59, p17, and p12 small subunits. So far, the contribution of the noncatalytic subunits to hPolε function is not well understood. Using pre-steady-state kinetic methods, we established a minimal kinetic mechanism for DNA polymerization and editing catalyzed by the hPolε holoenzyme. Compared with the 140-kDa N-terminal catalytic fragment of p261 (p261N), which we kinetically characterized in our earlier studies, the presence of the p261 C-terminal domain (p261C) and the three small subunits increased the DNA binding affinity and the base substitution fidelity. Although the small subunits enhanced correct nucleotide incorporation efficiency, there was a wide range of rate constants when incorporating a correct nucleotide over a single-base mismatch. Surprisingly, the 3'→5' exonuclease activity of the hPolε holoenzyme was significantly slower than that of p261N when editing both matched and mismatched DNA substrates. This suggests that the presence of p261C and the three small subunits regulates the 3'→5' exonuclease activity of the hPolε holoenzyme. Together, the 3'→5' exonuclease activity and the variable mismatch extension activity modulate the overall fidelity of the hPolε holoenzyme by up to 3 orders of magnitude. Thus, the presence of p261C and the three noncatalytic subunits optimizes the dual enzymatic activities of the catalytic p261 subunit and makes the hPolε holoenzyme an efficient and faithful replicative DNA polymerase.
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Affiliation(s)
- Walter J Zahurancik
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Zucai Suo
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, USA.
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25
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Pérez-Arnaiz P, Dattani A, Smith V, Allers T. Haloferax volcanii-a model archaeon for studying DNA replication and repair. Open Biol 2020; 10:200293. [PMID: 33259746 PMCID: PMC7776575 DOI: 10.1098/rsob.200293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
The tree of life shows the relationship between all organisms based on their common ancestry. Until 1977, it comprised two major branches: prokaryotes and eukaryotes. Work by Carl Woese and other microbiologists led to the recategorization of prokaryotes and the proposal of three primary domains: Eukarya, Bacteria and Archaea. Microbiological, genetic and biochemical techniques were then needed to study the third domain of life. Haloferax volcanii, a halophilic species belonging to the phylum Euryarchaeota, has provided many useful tools to study Archaea, including easy culturing methods, genetic manipulation and phenotypic screening. This review will focus on DNA replication and DNA repair pathways in H. volcanii, how this work has advanced our knowledge of archaeal cellular biology, and how it may deepen our understanding of bacterial and eukaryotic processes.
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Affiliation(s)
| | | | | | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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26
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Obi I, Rentoft M, Singh V, Jamroskovic J, Chand K, Chorell E, Westerlund F, Sabouri N. Stabilization of G-quadruplex DNA structures in Schizosaccharomyces pombe causes single-strand DNA lesions and impedes DNA replication. Nucleic Acids Res 2020; 48:10998-11015. [PMID: 33045725 PMCID: PMC7641769 DOI: 10.1093/nar/gkaa820] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/09/2020] [Accepted: 09/17/2020] [Indexed: 12/30/2022] Open
Abstract
G-quadruplex (G4) structures are stable non-canonical DNA structures that are implicated in the regulation of many cellular pathways. We show here that the G4-stabilizing compound PhenDC3 causes growth defects in Schizosaccharomyces pombe cells, especially during S-phase in synchronized cultures. By visualizing individual DNA molecules, we observed shorter DNA fragments of newly replicated DNA in the PhenDC3-treated cells, suggesting that PhenDC3 impedes replication fork progression. Furthermore, a novel single DNA molecule damage assay revealed increased single-strand DNA lesions in the PhenDC3-treated cells. Moreover, chromatin immunoprecipitation showed enrichment of the leading-strand DNA polymerase at sites of predicted G4 structures, suggesting that these structures impede DNA replication. We tested a subset of these sites and showed that they form G4 structures, that they stall DNA synthesis in vitro and that they can be resolved by the breast cancer-associated Pif1 family helicases. Our results thus suggest that G4 structures occur in S. pombe and that stabilized/unresolved G4 structures are obstacles for the replication machinery. The increased levels of DNA damage might further highlight the association of the human Pif1 helicase with familial breast cancer and the onset of other human diseases connected to unresolved G4 structures.
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Affiliation(s)
- Ikenna Obi
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| | - Matilda Rentoft
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| | - Vandana Singh
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Jan Jamroskovic
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| | - Karam Chand
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Erik Chorell
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Nasim Sabouri
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
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27
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Guilliam TA, Yeeles JTP. An updated perspective on the polymerase division of labor during eukaryotic DNA replication. Crit Rev Biochem Mol Biol 2020; 55:469-481. [PMID: 32883112 DOI: 10.1080/10409238.2020.1811630] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In eukaryotes three DNA polymerases (Pols), α, δ, and ε, are tasked with bulk DNA synthesis of nascent strands during genome duplication. Most evidence supports a model where Pol α initiates DNA synthesis before Pol ε and Pol δ replicate the leading and lagging strands, respectively. However, a number of recent reports, enabled by advances in biochemical and genetic techniques, have highlighted emerging roles for Pol δ in all stages of leading-strand synthesis; initiation, elongation, and termination, as well as fork restart. By focusing on these studies, this review provides an updated perspective on the division of labor between the replicative polymerases during DNA replication.
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Affiliation(s)
- Thomas A Guilliam
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Joseph T P Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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28
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Cerritelli SM, Iranzo J, Sharma S, Chabes A, Crouch RJ, Tollervey D, El Hage A. High density of unrepaired genomic ribonucleotides leads to Topoisomerase 1-mediated severe growth defects in absence of ribonucleotide reductase. Nucleic Acids Res 2020; 48:4274-4297. [PMID: 32187369 PMCID: PMC7192613 DOI: 10.1093/nar/gkaa103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
Cellular levels of ribonucleoside triphosphates (rNTPs) are much higher than those of deoxyribonucleoside triphosphates (dNTPs), thereby influencing the frequency of incorporation of ribonucleoside monophosphates (rNMPs) by DNA polymerases (Pol) into DNA. RNase H2-initiated ribonucleotide excision repair (RER) efficiently removes single rNMPs in genomic DNA. However, processing of rNMPs by Topoisomerase 1 (Top1) in absence of RER induces mutations and genome instability. Here, we greatly increased the abundance of genomic rNMPs in Saccharomyces cerevisiae by depleting Rnr1, the major subunit of ribonucleotide reductase, which converts ribonucleotides to deoxyribonucleotides. We found that in strains that are depleted of Rnr1, RER-deficient, and harbor an rNTP-permissive replicative Pol mutant, excessive accumulation of single genomic rNMPs severely compromised growth, but this was reversed in absence of Top1. Thus, under Rnr1 depletion, limited dNTP pools slow DNA synthesis by replicative Pols and provoke the incorporation of high levels of rNMPs in genomic DNA. If a threshold of single genomic rNMPs is exceeded in absence of RER and presence of limited dNTP pools, Top1-mediated genome instability leads to severe growth defects. Finally, we provide evidence showing that accumulation of RNA/DNA hybrids in absence of RNase H1 and RNase H2 leads to cell lethality under Rnr1 depletion.
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Affiliation(s)
- Susana M Cerritelli
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jaime Iranzo
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87, Sweden
| | - Robert J Crouch
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - David Tollervey
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Aziz El Hage
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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29
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Acharya N, Khandagale P, Thakur S, Sahu JK, Utkalaja BG. Quaternary structural diversity in eukaryotic DNA polymerases: monomeric to multimeric form. Curr Genet 2020; 66:635-655. [PMID: 32236653 DOI: 10.1007/s00294-020-01071-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/13/2020] [Accepted: 03/24/2020] [Indexed: 12/14/2022]
Abstract
Sixteen eukaryotic DNA polymerases have been identified and studied so far. Based on the sequence similarity of the catalytic subunits of DNA polymerases, these have been classified into four A, B, X and Y families except PrimPol, which belongs to the AEP family. The quaternary structure of these polymerases also varies depending upon whether they are composed of one or more subunits. Therefore, in this review, we used a quaternary structure-based classification approach to group DNA polymerases as either monomeric or multimeric and highlighted functional significance of their accessory subunits. Additionally, we have briefly summarized various DNA polymerase discoveries from a historical perspective, emphasized unique catalytic mechanism of each DNA polymerase and highlighted recent advances in understanding their cellular functions.
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Affiliation(s)
- Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India.
| | - Prashant Khandagale
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Shweta Thakur
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Jugal Kishor Sahu
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Bhabasha Gyanadeep Utkalaja
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
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30
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Nava GM, Grasso L, Sertic S, Pellicioli A, Muzi Falconi M, Lazzaro F. One, No One, and One Hundred Thousand: The Many Forms of Ribonucleotides in DNA. Int J Mol Sci 2020; 21:E1706. [PMID: 32131532 PMCID: PMC7084774 DOI: 10.3390/ijms21051706] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 12/14/2022] Open
Abstract
In the last decade, it has become evident that RNA is frequently found in DNA. It is now well established that single embedded ribonucleoside monophosphates (rNMPs) are primarily introduced by DNA polymerases and that longer stretches of RNA can anneal to DNA, generating RNA:DNA hybrids. Among them, the most studied are R-loops, peculiar three-stranded nucleic acid structures formed upon the re-hybridization of a transcript to its template DNA. In addition, polyribonucleotide chains are synthesized to allow DNA replication priming, double-strand breaks repair, and may as well result from the direct incorporation of consecutive rNMPs by DNA polymerases. The bright side of RNA into DNA is that it contributes to regulating different physiological functions. The dark side, however, is that persistent RNA compromises genome integrity and genome stability. For these reasons, the characterization of all these structures has been under growing investigation. In this review, we discussed the origin of single and multiple ribonucleotides in the genome and in the DNA of organelles, focusing on situations where the aberrant processing of RNA:DNA hybrids may result in multiple rNMPs embedded in DNA. We concluded by providing an overview of the currently available strategies to study the presence of single and multiple ribonucleotides in DNA in vivo.
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Affiliation(s)
| | | | | | | | - Marco Muzi Falconi
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy; (G.M.N.); (L.G.); (S.S.); (A.P.)
| | - Federico Lazzaro
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy; (G.M.N.); (L.G.); (S.S.); (A.P.)
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31
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Lancey C, Tehseen M, Raducanu VS, Rashid F, Merino N, Ragan TJ, Savva CG, Zaher MS, Shirbini A, Blanco FJ, Hamdan SM, De Biasio A. Structure of the processive human Pol δ holoenzyme. Nat Commun 2020; 11:1109. [PMID: 32111820 PMCID: PMC7048817 DOI: 10.1038/s41467-020-14898-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/07/2020] [Indexed: 01/01/2023] Open
Abstract
In eukaryotes, DNA polymerase δ (Pol δ) bound to the proliferating cell nuclear antigen (PCNA) replicates the lagging strand and cooperates with flap endonuclease 1 (FEN1) to process the Okazaki fragments for their ligation. We present the high-resolution cryo-EM structure of the human processive Pol δ–DNA–PCNA complex in the absence and presence of FEN1. Pol δ is anchored to one of the three PCNA monomers through the C-terminal domain of the catalytic subunit. The catalytic core sits on top of PCNA in an open configuration while the regulatory subunits project laterally. This arrangement allows PCNA to thread and stabilize the DNA exiting the catalytic cleft and recruit FEN1 to one unoccupied monomer in a toolbelt fashion. Alternative holoenzyme conformations reveal important functional interactions that maintain PCNA orientation during synthesis. This work sheds light on the structural basis of Pol δ’s activity in replicating the human genome. Pol δ bound to the proliferating cell nuclear antigen (PCNA) replicates the lagging strand in eukaryotes and cooperates with flap endonuclease 1 (FEN1) to process the Okazaki fragments for their ligation. Here, the authors present a Cryo-EM structure of the human 4-subunit Pol δ bound to DNA and PCNA in a replicating state with an incoming nucleotide in the active site.
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Affiliation(s)
- Claudia Lancey
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester, LE1 7HB, UK
| | - Muhammad Tehseen
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Vlad-Stefan Raducanu
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Fahad Rashid
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Nekane Merino
- CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160, Derio, Spain
| | - Timothy J Ragan
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester, LE1 7HB, UK
| | - Christos G Savva
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester, LE1 7HB, UK
| | - Manal S Zaher
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Afnan Shirbini
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia
| | - Francisco J Blanco
- CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160, Derio, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Samir M Hamdan
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia.
| | - Alfredo De Biasio
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester, LE1 7HB, UK.
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32
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Hoitsma NM, Whitaker AM, Schaich MA, Smith MR, Fairlamb MS, Freudenthal BD. Structure and function relationships in mammalian DNA polymerases. Cell Mol Life Sci 2020; 77:35-59. [PMID: 31722068 PMCID: PMC7050493 DOI: 10.1007/s00018-019-03368-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 12/19/2022]
Abstract
DNA polymerases are vital for the synthesis of new DNA strands. Since the discovery of DNA polymerase I in Escherichia coli, a diverse library of mammalian DNA polymerases involved in DNA replication, DNA repair, antibody generation, and cell checkpoint signaling has emerged. While the unique functions of these DNA polymerases are differentiated by their association with accessory factors and/or the presence of distinctive catalytic domains, atomic resolution structures of DNA polymerases in complex with their DNA substrates have revealed mechanistic subtleties that contribute to their specialization. In this review, the structure and function of all 15 mammalian DNA polymerases from families B, Y, X, and A will be reviewed and discussed with special emphasis on the insights gleaned from recently published atomic resolution structures.
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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
| | - Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Matthew A Schaich
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Mallory R Smith
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Max S Fairlamb
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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33
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Wanrooij PH, Chabes A. Ribonucleotides in mitochondrial DNA. FEBS Lett 2019; 593:1554-1565. [PMID: 31093968 DOI: 10.1002/1873-3468.13440] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/09/2019] [Accepted: 05/09/2019] [Indexed: 01/05/2023]
Abstract
The incorporation of ribonucleotides (rNMPs) into DNA during genome replication has gained substantial attention in recent years and has been shown to be a significant source of genomic instability. Studies in yeast and mammals have shown that the two genomes, the nuclear DNA (nDNA) and the mitochondrial DNA (mtDNA), differ with regard to their rNMP content. This is largely due to differences in rNMP repair - whereas rNMPs are efficiently removed from the nuclear genome, mitochondria lack robust mechanisms for removal of single rNMPs incorporated during DNA replication. In this minireview, we describe the processes that determine the frequency of rNMPs in the mitochondrial genome and summarise recent findings regarding the effect of incorporated rNMPs on mtDNA stability and function.
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Affiliation(s)
- Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå University, Sweden
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34
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Development of an MSI-positive colon tumor with aberrant DNA methylation in a PPAP patient. J Hum Genet 2019; 64:729-740. [PMID: 31089268 DOI: 10.1038/s10038-019-0611-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/18/2019] [Accepted: 04/19/2019] [Indexed: 02/07/2023]
Abstract
Polymerase proofreading-associated polyposis (PPAP) is a disease caused by germline variations in the POLE and POLD1 genes that encode catalytic subunits of DNA polymerases. Studies of cancer genomes have identified somatic mutations in these genes, suggesting the importance of polymerase proofreading of DNA replication in suppressing tumorigenesis. Here, we identified a germline frameshift variation in the POLE gene (c.4191_4192delCT, p.Tyr1398*) in a case with multiple adenomatous polyps and three synchronous colon cancers. Interestingly, one of the colon cancers showed microsatellite instability-high (MSI-H) and another microsatellite stable. Immunohistochemical staining revealed that the MSI-H tumor cells lost the expression of MLH1 protein. Whole genome sequencing of the MSI-H tumor did not find pathogenic somatic mutations in mismatch repair genes but found frameshift mutations in the TET genes that catalyze 5-methylcytosine hydroxylation. Bisulfite sequencing of the tumor corroborated an increase in the number of hypermethylated regions including the MLH1 promoter. These data indicate that PPAP patients might develop MSI-positive tumors through epigenetic silencing of MLH1. These findings will contribute to comprehensive understanding of the molecular basis of tumors that involve deficiency of proofreading activity of DNA polymerases.
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35
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Park VS, Pursell ZF. POLE proofreading defects: Contributions to mutagenesis and cancer. DNA Repair (Amst) 2019; 76:50-59. [PMID: 30818169 PMCID: PMC6467506 DOI: 10.1016/j.dnarep.2019.02.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/14/2022]
Abstract
DNA polymerases are uniquely poised to contribute to the elevated mutation burdens seen in many human tumors. These mutations can arise through a number of different polymerase-dependent mechanisms, including intrinsic errors made using template DNA and precursor dNTPs free from chemical modifications, misinsertion events opposite chemically damaged template DNA or insertion events using modified nucleotides. While specific DNA repair polymerases have been known to contribute to tumorigenesis, the role of replication polymerases in mutagenesis in human disease has come into sharp focus over the last decade. This review describes how mutations in these replication DNA polymerases help to drive mutagenesis and tumor development, with particular attention to DNA polymerase epsilon. Recent studies using cancer genome sequencing, mutational signature analyses, yeast and mouse models, and the influence of mismatch repair on tumors with DNA polymerase mutations are discussed.
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Affiliation(s)
- Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA; Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA, USA.
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36
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Khandagale P, Peroumal D, Manohar K, Acharya N. Human DNA polymerase delta is a pentameric holoenzyme with a dimeric p12 subunit. Life Sci Alliance 2019; 2:2/2/e201900323. [PMID: 30885984 PMCID: PMC6424025 DOI: 10.26508/lsa.201900323] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/04/2019] [Accepted: 03/11/2019] [Indexed: 01/07/2023] Open
Abstract
The subunit p12 of human DNA polymerase delta (hPolδ) can dimerize, facilitating its interaction with PCNA and suggesting that hPolδ exists in a pentameric form in the cell. Human DNA polymerase delta (Polδ), a holoenzyme consisting of p125, p50, p68, and p12 subunits, plays an essential role in DNA replication, repair, and recombination. Herein, using multiple physicochemical and cellular approaches, we found that the p12 protein forms a dimer in solution. In vitro reconstitution and pull down of cellular Polδ by tagged p12 substantiate the pentameric nature of this critical holoenzyme. Furthermore, a consensus proliferating nuclear antigen (PCNA) interaction protein motif at the extreme carboxyl-terminal tail and a homodimerization domain at the amino terminus of the p12 subunit were identified. Mutational analyses of these motifs in p12 suggest that dimerization facilitates p12 binding to the interdomain connecting loop of PCNA. In addition, we observed that oligomerization of the smallest subunit of Polδ is evolutionarily conserved as Cdm1 of Schizosaccharomyces pombe also dimerizes. Thus, we suggest that human Polδ is a pentameric complex with a dimeric p12 subunit, and discuss implications of p12 dimerization in enzyme architecture and PCNA interaction during DNA replication.
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Affiliation(s)
- Prashant Khandagale
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Doureradjou Peroumal
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Kodavati Manohar
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
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37
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Valle L, de Voer RM, Goldberg Y, Sjursen W, Försti A, Ruiz-Ponte C, Caldés T, Garré P, Olsen MF, Nordling M, Castellvi-Bel S, Hemminki K. Update on genetic predisposition to colorectal cancer and polyposis. Mol Aspects Med 2019; 69:10-26. [PMID: 30862463 DOI: 10.1016/j.mam.2019.03.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/26/2019] [Accepted: 03/05/2019] [Indexed: 02/06/2023]
Abstract
The present article summarizes recent developments in the characterization of genetic predisposition to colorectal cancer (CRC). The main themes covered include new hereditary CRC and polyposis syndromes, non-CRC hereditary cancer genes found mutated in CRC patients, strategies used to identify novel causal genes, and review of candidate genes that have been proposed to predispose to CRC and/or colonic polyposis. We provide an overview of newly described genes and syndromes associated with predisposition to CRC and polyposis, including: polymerase proofreading-associated polyposis, NTHL1-associated polyposis, mismatch repair gene biallelic inactivation-related adenomatous polyposis (including MSH3- and MLH3-associated polyposes), GREM1-associated mixed polyposis, RNF43-associated serrated polyposis, and RPS20 mutations as a rare cause of hereditary nonpolyposis CRC. The implementation of next generation sequencing approaches for genetic testing has exposed the presence of pathogenic germline variants in genes associated with hereditary cancer syndromes not traditionally linked to CRC, which may have an impact on genetic testing, counseling and surveillance. The identification of new hereditary CRC and polyposis genes has not deemed an easy endeavor, even though known CRC-related genes explain a small proportion of the estimated familial risk. Whole-genome sequencing may offer a technology for increasing this proportion, particularly if applied on pedigree data allowing linkage type of analysis. The final section critically surveys the large number of candidate genes that have been recently proposed for CRC predisposition.
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Affiliation(s)
- Laura Valle
- Hereditary Cancer Program, Catalan Institute of Oncology, Hospitalet de Llobregat, Spain; Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), IDIBELL, Hospitalet de Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Spain.
| | - Richarda M de Voer
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Yael Goldberg
- Raphael Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel
| | - Wenche Sjursen
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Medical Genetics, St Olavs University Hospital, Trondheim, Norway
| | - Asta Försti
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120, Heidelberg, Germany
| | - Clara Ruiz-Ponte
- Fundación Pública Galega de Medicina Xenómica, Grupo de Medicina Xenómica, Santiago de Compostela, Spain; Instituto de Investigación Sanitaria de Santiago (IDIS), Santiago de Compostela, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain
| | - Trinidad Caldés
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Spain; Oncology Molecular Laboratory, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Pilar Garré
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Spain; Oncology Molecular Laboratory, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Maren F Olsen
- Department of Medical Genetics, St Olavs University Hospital, Trondheim, Norway
| | - Margareta Nordling
- Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Department of Clinical Pathology and Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Sergi Castellvi-Bel
- Genetic Predisposition to Gastrointestinal Cancer Group, Gastrointestinal and Pancreatic Oncology Team, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain.
| | - Kari Hemminki
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120, Heidelberg, Germany.
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38
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Affiliation(s)
- Vito Genna
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Elisa Donati
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
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39
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Zhou ZX, Williams JS, Kunkel TA. Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis. J Vis Exp 2018. [PMID: 30102287 DOI: 10.3791/58020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The presence of ribonucleotides in nuclear DNA has been shown to be a source of genomic instability. The extent of ribonucleotide incorporation can be assessed by alkaline hydrolysis and gel electrophoresis as RNA is highly susceptible to hydrolysis in alkaline conditions. This, in combination with Southern blot analysis can be used to determine the location and strand into which the ribonucleotides have been incorporated. However, this procedure is only semi-quantitative and may not be sensitive enough to detect small changes in ribonucleotide content, although strand-specific Southern blot probing improves the sensitivity. As a measure of one of the most striking biological consequences of ribonucleotides in DNA, spontaneous mutagenesis can be analyzed using a forward mutation assay. Using appropriate reporter genes, rare mutations that results in the loss of function can be selected and overall and specific mutation rates can be measured by combining data from fluctuation experiments with DNA sequencing of the reporter gene. The fluctuation assay is applicable to examine a wide variety of mutagenic processes in specific genetic background or growth conditions.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS;
| | - Jessica S Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS
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40
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Stodola JL, Burgers PM. Mechanism of Lagging-Strand DNA Replication in Eukaryotes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:117-133. [PMID: 29357056 DOI: 10.1007/978-981-10-6955-0_6] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This chapter focuses on the enzymes and mechanisms involved in lagging-strand DNA replication in eukaryotic cells. Recent structural and biochemical progress with DNA polymerase α-primase (Pol α) provides insights how each of the millions of Okazaki fragments in a mammalian cell is primed by the primase subunit and further extended by its polymerase subunit. Rapid kinetic studies of Okazaki fragment elongation by Pol δ illuminate events when the polymerase encounters the double-stranded RNA-DNA block of the preceding Okazaki fragment. This block acts as a progressive molecular break that provides both time and opportunity for the flap endonuclease 1 (FEN1) to access the nascent flap and cut it. The iterative action of Pol δ and FEN1 is coordinated by the replication clamp PCNA and produces a regulated degradation of the RNA primer, thereby preventing the formation of long-strand displacement flaps. Occasional long flaps are further processed by backup nucleases including Dna2.
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Affiliation(s)
- Joseph L Stodola
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA.
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41
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Orebaugh CD, Lujan SA, Burkholder AB, Clausen AR, Kunkel TA. Mapping Ribonucleotides Incorporated into DNA by Hydrolytic End-Sequencing. Methods Mol Biol 2018; 1672:329-345. [PMID: 29043634 DOI: 10.1007/978-1-4939-7306-4_23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ribonucleotides embedded within DNA render the DNA sensitive to the formation of single-stranded breaks under alkali conditions. Here, we describe a next-generation sequencing method called hydrolytic end sequencing (HydEn-seq) to map ribonucleotides inserted into the genome of Saccharomyce cerevisiae strains deficient in ribonucleotide excision repair. We use this method to map several genomic features in wild-type and replicase variant yeast strains.
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Affiliation(s)
- Clinton D Orebaugh
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Scott A Lujan
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics, National Institute for Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, NC, USA
| | - Anders R Clausen
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute for Environmental Health Sciences, National Institute of Health (NIH), 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA.
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42
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Analysis of Replicative Polymerase Usage by Ribonucleotide Incorporation. Methods Mol Biol 2018; 1672:239-259. [PMID: 29043629 DOI: 10.1007/978-1-4939-7306-4_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mapping the usage of replicative DNA polymerases has previously proved to be technically challenging. By exploiting mutant polymerases that incorporate ribonucleotides into the DNA with a significantly higher proficiency than their wild-type counterparts, we and others have developed methods that can identify what proportion of each DNA strand (i.e., the Watson and Crick strands) is replicated by a specific DNA polymerase. The incorporation of excess ribonucleotides by a mutated polymerase effectively marks, in each individual cells, the DNA strand that is replicated by that specific mutated polymerase. Changes to DNA polymerase usage can be examined at specific loci by Southern blot analysis while a global analysis of polymerase usage can be achieved by applying next-generation sequencing. This genome-wide data also provides a direct measure of replication origin efficiency and can be used to indirectly calculate replication timing.
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43
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Garbacz MA, Lujan SA, Burkholder AB, Cox PB, Wu Q, Zhou ZX, Haber JE, Kunkel TA. Evidence that DNA polymerase δ contributes to initiating leading strand DNA replication in Saccharomyces cerevisiae. Nat Commun 2018; 9:858. [PMID: 29487291 PMCID: PMC5829166 DOI: 10.1038/s41467-018-03270-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 02/01/2018] [Indexed: 01/01/2023] Open
Abstract
To investigate nuclear DNA replication enzymology in vivo, we have studied Saccharomyces cerevisiae strains containing a pol2-16 mutation that inactivates the catalytic activities of DNA polymerase ε (Pol ε). Although pol2-16 mutants survive, they present very tiny spore colonies, increased doubling time, larger than normal cells, aberrant nuclei, and rapid acquisition of suppressor mutations. These phenotypes reveal a severe growth defect that is distinct from that of strains that lack only Pol ε proofreading (pol2-4), consistent with the idea that Pol ε is the major leading-strand polymerase used for unstressed DNA replication. Ribonucleotides are incorporated into the pol2-16 genome in patterns consistent with leading-strand replication by Pol δ when Pol ε is absent. More importantly, ribonucleotide distributions at replication origins suggest that in strains encoding all three replicases, Pol δ contributes to initiation of leading-strand replication. We describe two possible models. DNA polymerases δ and ε (Pols δ and ε) are thought to be responsible for lagging and leading strand synthesis, respectively. Here the authors present evidence that Pol δ contributes to the initiation of leading strand replication in budding yeast by synthesizing DNA of both strands at replication origins.
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Affiliation(s)
- Marta A Garbacz
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA
| | - Scott A Lujan
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA
| | - Phillip B Cox
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA
| | - Qiuqin Wu
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA
| | - Zhi-Xiong Zhou
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA
| | - James E Haber
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, Durham, NC, 27709, USA.
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Li H, O'Donnell ME. The Eukaryotic CMG Helicase at the Replication Fork: Emerging Architecture Reveals an Unexpected Mechanism. Bioessays 2018; 40. [PMID: 29405332 DOI: 10.1002/bies.201700208] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/27/2017] [Indexed: 01/12/2023]
Abstract
The eukaryotic helicase is an 11-subunit machine containing an Mcm2-7 motor ring that encircles DNA, Cdc45 and the GINS tetramer, referred to as CMG (Cdc45, Mcm2-7, GINS). CMG is "built" on DNA at origins in two steps. First, two Mcm2-7 rings are assembled around duplex DNA at origins in G1 phase, forming the Mcm2-7 "double hexamer." In a second step, in S phase Cdc45 and GINS are assembled onto each Mcm2-7 ring, hence producing two CMGs that ultimately form two replication forks that travel in opposite directions. Here, we review recent findings about CMG structure and function. The CMG unwinds the parental duplex and is also the organizing center of the replisome: it binds DNA polymerases and other factors. EM studies reveal a 20-subunit core replisome with the leading Pol ϵ and lagging Pol α-primase on opposite faces of CMG, forming a fundamentally asymmetric architecture. Structural studies of CMG at a replication fork reveal unexpected details of how CMG engages the DNA fork. The structures of CMG and the Mcm2-7 double hexamer on DNA suggest a completely unanticipated process for formation of bidirectional replication forks at origins.
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Affiliation(s)
- Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Michael E O'Donnell
- Department of DNA Replication, Rockefeller University and HHMI, New York, NY 10065, USA
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45
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Xiong W, Zhai M, Yu X, Wei L, Mao J, Liu J, Xie J, Li B. Comparative RNA-sequencing analysis of ER-based HSP90 functions and signal pathways in Tribolium castaneum. Cell Stress Chaperones 2018; 23:29-43. [PMID: 28681272 PMCID: PMC5741579 DOI: 10.1007/s12192-017-0821-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 06/10/2017] [Accepted: 06/14/2017] [Indexed: 12/18/2022] Open
Abstract
Tribolium castaneum, the red flour beetle, is a major agriculture pest that damages stored grains and cereal products. Heat-shock protein 90 of T. castaneum (Tchsp90) has been reported to play pivotal roles in heat stress response, development, reproduction, and life span. However, the signaling pathway of Tchsp90 remains unclear. Thus, the global transcriptome profiles between RNA interference (RNAi)-treated insects (ds-Tchsp90) and control insects of T. castaneum were investigated and compared by RNA sequencing. In all, we obtained 14,145,451 sequence reads, which assembled into 13,243 genes. Among these genes, 461 differentially expressed genes (DEGs) were identified between the ds-Tchsp90 and control samples. These DEGs were classified into 44 gene ontology (GO) functional groups, including the cellular process, the response to stimulus, the immune system process, the development process, and reproduction. Interestingly, knocking down the expression of Tchsp90 suppressed both the DNA replication and cell division signaling pathways, which most likely modulated the effects of Tchsp90 on development, reproduction, and life span. Moreover, the DEGs encoding AnnexinB9, frizzled-4, sno, Fem1B, TSL, and CSW might be related to the regulation of the development and reproduction of ds-Tchsp90 insects. The DEGs including TLR6, PGRP2, defensin1, and defensin2 were involved in heat stress and immune response simultaneously, which suggested that cross talk might exist between immunity and stress response. Additionally, RNAi of Tchsp90 altered large-scale serine protease (sp) gene expression patterns and amplified the SP signaling pathway to regulate the development and reproduction as well as the stress response and innate immunity in T. castaneum. All these results shed new light onto the regulatory mechanism of Tchsp90 involved in insect physiology and could further facilitate research into appropriate and sustainable pest control management.
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Affiliation(s)
- Wenfeng Xiong
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Mengfan Zhai
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Xiaojuan Yu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Luting Wei
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Jinjuan Mao
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Juanjuan Liu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Jia Xie
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Bin Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
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46
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Kreisel K, Engqvist MKM, Clausen AR. Simultaneous Mapping and Quantitation of Ribonucleotides in Human Mitochondrial DNA. J Vis Exp 2017. [PMID: 29286447 PMCID: PMC5755389 DOI: 10.3791/56551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Established approaches to estimate the number of ribonucleotides present in a genome are limited to the quantitation of incorporated ribonucleotides using short synthetic DNA fragments or plasmids as templates and then extrapolating the results to the whole genome. Alternatively, the number of ribonucleotides present in a genome may be estimated using alkaline gels or Southern blots. More recent in vivo approaches employ Next-generation sequencing allowing genome-wide mapping of ribonucleotides, providing the position and identity of embedded ribonucleotides. However, they do not allow quantitation of the number of ribonucleotides which are incorporated into a genome. Here we describe how to simultaneously map and quantitate the number of ribonucleotides which are incorporated into human mitochondrial DNA in vivo by Next-generation sequencing. We use highly intact DNA and introduce sequence specific double strand breaks by digesting it with an endonuclease, subsequently hydrolyzing incorporated ribonucleotides with alkali. The generated ends are ligated with adapters and these ends are sequenced on a Next-generation sequencing machine. The absolute number of ribonucleotides can be calculated as the number of reads outside the recognition site per average number of reads at the recognition site for the sequence specific endonuclease. This protocol may also be utilized to map and quantitate free nicks in DNA and allows adaption to map other DNA lesions that can be processed to 5´-OH ends or 5´-phosphate ends. Furthermore, this method can be applied to any organism, given that a suitable reference genome is available. This protocol therefore provides an important tool to study DNA replication, 5´-end processing, DNA damage, and DNA repair.
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Affiliation(s)
- Katrin Kreisel
- Department for Medical Biochemistry and Cell Biology, University of Gothenburg
| | - Martin K M Engqvist
- Department for Medical Biochemistry and Cell Biology, University of Gothenburg; Department of Biology and Biological Engineering, Chalmers University of Technology
| | - Anders R Clausen
- Department for Medical Biochemistry and Cell Biology, University of Gothenburg;
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47
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Poulos RC, Olivier J, Wong JWH. The interaction between cytosine methylation and processes of DNA replication and repair shape the mutational landscape of cancer genomes. Nucleic Acids Res 2017; 45:7786-7795. [PMID: 28531315 PMCID: PMC5737810 DOI: 10.1093/nar/gkx463] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/15/2017] [Indexed: 12/31/2022] Open
Abstract
Methylated cytosines (5mCs) are frequently mutated in the genome. However, no studies have yet comprehensively analysed mutation–methylation associations across cancer types. Here we analyse 916 cancer genomes, together with tissue type-specific methylation and replication timing data. We describe a strong mutation–methylation association across colorectal cancer subtypes, most interestingly in samples with microsatellite instability (MSI) or Polymerase epsilon (POLE) exonuclease domain mutations. By analysing genomic regions with differential mismatch repair (MMR) efficiency, we suggest a possible role for MMR in the correction of 5mC deamination events, potentially accounting for the high rate of 5mC mutation accumulation in MSI tumours. Additionally, we propose that mutant POLE asserts a mutator phenotype specifically at 5mCs, and we find coding mutation hotspots in POLE-mutant cancers at highly-methylated CpGs in the tumour-suppressor genes APC and TP53. Finally, using multivariable regression models, we demonstrate that different cancers exhibit distinct mutation–methylation associations, with DNA repair influencing such associations in certain cancer genomes. Taken together, we find differential associations with methylation that are vital for accurately predicting expected mutation loads across cancer types. Our findings reveal links between methylation and common mutation and repair processes, with these mechanisms defining a key part of the mutational landscape of cancer genomes.
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Affiliation(s)
- Rebecca C Poulos
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Sydney, NSW 2052, Australia
| | - Jake Olivier
- School of Mathematics and Statistics, The Red Centre, UNSW Sydney, NSW 2052, Australia
| | - Jason W H Wong
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Sydney, NSW 2052, Australia
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48
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Paschalis V, Le Chatelier E, Green M, Nouri H, Képès F, Soultanas P, Janniere L. Interactions of the Bacillus subtilis DnaE polymerase with replisomal proteins modulate its activity and fidelity. Open Biol 2017; 7:170146. [PMID: 28878042 PMCID: PMC5627055 DOI: 10.1098/rsob.170146] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/01/2017] [Indexed: 01/09/2023] Open
Abstract
During Bacillus subtilis replication two replicative polymerases function at the replisome to collectively carry out genome replication. In a reconstituted in vitro replication assay, PolC is the main polymerase while the lagging strand DnaE polymerase briefly extends RNA primers synthesized by the primase DnaG prior to handing-off DNA synthesis to PolC. Here, we show in vivo that (i) the polymerase activity of DnaE is essential for both the initiation and elongation stages of DNA replication, (ii) its error rate varies inversely with PolC concentration, and (iii) its misincorporations are corrected by the mismatch repair system post-replication. We also found that the error rates in cells encoding mutator forms of both PolC and DnaE are significantly higher (up to 15-fold) than in PolC mutants. In vitro, we showed that (i) the polymerase activity of DnaE is considerably stimulated by DnaN, SSB and PolC, (ii) its error-prone activity is strongly inhibited by DnaN, and (iii) its errors are proofread by the 3' > 5' exonuclease activity of PolC in a stable template-DnaE-PolC complex. Collectively our data show that protein-protein interactions within the replisome modulate the activity and fidelity of DnaE, and confirm the prominent role of DnaE during B. subtilis replication.
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Affiliation(s)
- Vasileios Paschalis
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Emmanuelle Le Chatelier
- Institut National de la Recherche Agronomique, Génétique Microbienne, 78350 Jouy-en-Josas, France
| | - Matthew Green
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Hamid Nouri
- iSSB, Genopole, CNRS, Univ EVRY, Université Paris-Saclay, Génopole Campus 1, Genavenir 6, 5 rue Henri Desbruères, 91030 Evry, France
| | - François Képès
- iSSB, Genopole, CNRS, Univ EVRY, Université Paris-Saclay, Génopole Campus 1, Genavenir 6, 5 rue Henri Desbruères, 91030 Evry, France
| | - Panos Soultanas
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Laurent Janniere
- iSSB, Genopole, CNRS, Univ EVRY, Université Paris-Saclay, Génopole Campus 1, Genavenir 6, 5 rue Henri Desbruères, 91030 Evry, France
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DNA damage tolerance in hematopoietic stem and progenitor cells in mice. Proc Natl Acad Sci U S A 2017; 114:E6875-E6883. [PMID: 28761001 DOI: 10.1073/pnas.1706508114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
DNA damage tolerance (DDT) enables bypassing of DNA lesions during replication, thereby preventing fork stalling, replication stress, and secondary DNA damage related to fork stalling. Three modes of DDT have been documented: translesion synthesis (TLS), template switching (TS), and repriming. TLS and TS depend on site-specific PCNA K164 monoubiquitination and polyubiquitination, respectively. To investigate the role of DDT in maintaining hematopoietic stem cells (HSCs) and progenitors, we used PcnaK164R/K164R mice as a unique DDT-defective mouse model. Analysis of the composition of HSCs and HSC-derived multipotent progenitors (MPPs) revealed a significantly reduced number of HSCs, likely owing to increased differentiation of HSCs toward myeloid/erythroid-associated MPP2s. This skewing came at the expense of the number of lymphoid-primed MPP4s, which appeared to be compensated for by increased MPP4 proliferation. Furthermore, defective DDT decreased the numbers of MPP-derived common lymphoid progenitor (CLP), common myeloid progenitor (CMP), megakaryocyte-erythroid progenitor (MEP), and granulocyte-macrophage progenitor (GMP) cells, accompanied by increased cell cycle arrest in CMPs. The HSC and MPP phenotypes are reminiscent of premature aging and stressed hematopoiesis, and indeed progressed with age and were exacerbated on cisplatin exposure. Bone marrow transplantations revealed a strong cell intrinsic defect of DDT-deficient HSCs in reconstituting lethally irradiated mice and a strong competitive disadvantage when cotransplanted with wild-type HSCs. These findings indicate a critical role of DDT in maintaining HSCs and progenitor cells, and in preventing premature aging.
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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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