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Galanti L, Peritore M, Gnügge R, Cannavo E, Heipke J, Palumbieri MD, Steigenberger B, Symington LS, Cejka P, Pfander B. Dbf4-dependent kinase promotes cell cycle controlled resection of DNA double-strand breaks and repair by homologous recombination. Nat Commun 2024; 15:2890. [PMID: 38570537 PMCID: PMC10991553 DOI: 10.1038/s41467-024-46951-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 03/13/2024] [Indexed: 04/05/2024] Open
Abstract
DNA double-strand breaks (DSBs) can be repaired by several pathways. In eukaryotes, DSB repair pathway choice occurs at the level of DNA end resection and is controlled by the cell cycle. Upon cell cycle-dependent activation, cyclin-dependent kinases (CDKs) phosphorylate resection proteins and thereby stimulate end resection and repair by homologous recombination (HR). However, inability of CDK phospho-mimetic mutants to bypass this cell cycle regulation, suggests that additional cell cycle regulators may be important. Here, we identify Dbf4-dependent kinase (DDK) as a second major cell cycle regulator of DNA end resection. Using inducible genetic and chemical inhibition of DDK in budding yeast and human cells, we show that end resection and HR require activation by DDK. Mechanistically, DDK phosphorylates at least two resection nucleases in budding yeast: the Mre11 activator Sae2, which promotes resection initiation, as well as the Dna2 nuclease, which promotes resection elongation. Notably, synthetic activation of DDK allows limited resection and HR in G1 cells, suggesting that DDK is a key component of DSB repair pathway selection.
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Affiliation(s)
- Lorenzo Galanti
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
| | - Martina Peritore
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK
| | - Robert Gnügge
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Elda Cannavo
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Bellinzona, Switzerland
| | - Johannes Heipke
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
| | - Maria Dilia Palumbieri
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany
- Research Group of Proteomics and ADP-Ribosylation Signaling, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Barbara Steigenberger
- Mass Spectrometry Core Facility, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Boris Pfander
- Cell Biology, Dortmund Life Science Center (DOLCE), TU Dortmund University, Faculty of Chemistry and Chemical Biology, Dortmund, Germany.
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
- Institute for Genome Stability in Aging and Disease, University of Cologne, Medical Faculty, CECAD Research Center, Cologne, Germany.
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2
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Nasheuer HP, Meaney AM. Starting DNA Synthesis: Initiation Processes during the Replication of Chromosomal DNA in Humans. Genes (Basel) 2024; 15:360. [PMID: 38540419 PMCID: PMC10969946 DOI: 10.3390/genes15030360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 06/14/2024] Open
Abstract
The initiation reactions of DNA synthesis are central processes during human chromosomal DNA replication. They are separated into two main processes: the initiation events at replication origins, the start of the leading strand synthesis for each replicon, and the numerous initiation events taking place during lagging strand DNA synthesis. In addition, a third mechanism is the re-initiation of DNA synthesis after replication fork stalling, which takes place when DNA lesions hinder the progression of DNA synthesis. The initiation of leading strand synthesis at replication origins is regulated at multiple levels, from the origin recognition to the assembly and activation of replicative helicase, the Cdc45-MCM2-7-GINS (CMG) complex. In addition, the multiple interactions of the CMG complex with the eukaryotic replicative DNA polymerases, DNA polymerase α-primase, DNA polymerase δ and ε, at replication forks play pivotal roles in the mechanism of the initiation reactions of leading and lagging strand DNA synthesis. These interactions are also important for the initiation of signalling at unperturbed and stalled replication forks, "replication stress" events, via ATR (ATM-Rad 3-related protein kinase). These processes are essential for the accurate transfer of the cells' genetic information to their daughters. Thus, failures and dysfunctions in these processes give rise to genome instability causing genetic diseases, including cancer. In their influential review "Hallmarks of Cancer: New Dimensions", Hanahan and Weinberg (2022) therefore call genome instability a fundamental function in the development process of cancer cells. In recent years, the understanding of the initiation processes and mechanisms of human DNA replication has made substantial progress at all levels, which will be discussed in the review.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland;
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3
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Tye BK, Zhai Y. The Origin Recognition Complex: From Origin Selection to Replication Licensing in Yeast and Humans. BIOLOGY 2023; 13:13. [PMID: 38248444 PMCID: PMC10813338 DOI: 10.3390/biology13010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024]
Abstract
Understanding human DNA replication through the study of yeast has been an extremely fruitful journey. The minichromosome maintenance (MCM) 2-7 genes that encode the catalytic core of the eukaryotic replisome were initially identified through forward yeast genetics. The origin recognition complexes (ORC) that load the MCM hexamers at replication origins were purified from yeast extracts. We have reached an age where high-resolution cryoEM structures of yeast and human replication complexes can be compared side-by-side. Their similarities and differences are converging as alternative strategies that may deviate in detail but are shared by both species.
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Affiliation(s)
- Bik-Kwoon Tye
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China;
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4
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Xu Z, Feng J, Yu D, Huo Y, Ma X, Lam WH, Liu Z, Li XD, Ishibashi T, Dang S, Zhai Y. Synergism between CMG helicase and leading strand DNA polymerase at replication fork. Nat Commun 2023; 14:5849. [PMID: 37730685 PMCID: PMC10511561 DOI: 10.1038/s41467-023-41506-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 09/07/2023] [Indexed: 09/22/2023] Open
Abstract
The replisome that replicates the eukaryotic genome consists of at least three engines: the Cdc45-MCM-GINS (CMG) helicase that separates duplex DNA at the replication fork and two DNA polymerases, one on each strand, that replicate the unwound DNA. Here, we determined a series of cryo-electron microscopy structures of a yeast replisome comprising CMG, leading-strand polymerase Polε and three accessory factors on a forked DNA. In these structures, Polε engages or disengages with the motor domains of the CMG by occupying two alternative positions, which closely correlate with the rotational movement of the single-stranded DNA around the MCM pore. During this process, the polymerase remains stably coupled to the helicase using Psf1 as a hinge. This synergism is modulated by a concerted rearrangement of ATPase sites to drive DNA translocation. The Polε-MCM coupling is not only required for CMG formation to initiate DNA replication but also facilitates the leading-strand DNA synthesis mediated by Polε. Our study elucidates a mechanism intrinsic to the replisome that coordinates the activities of CMG and Polε to negotiate any roadblocks, DNA damage, and epigenetic marks encountered during translocation along replication forks.
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Affiliation(s)
- Zhichun Xu
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Jianrong Feng
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Daqi Yu
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Yunjing Huo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Xiaohui Ma
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Wai Hei Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Zheng Liu
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Xiang David Li
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Toyotaka Ishibashi
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.
- HKUST-Shenzhen Research Institute, 518057, Nanshan, Shenzhen, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
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5
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Jones ML, Aria V, Baris Y, Yeeles JTP. How Pol α-primase is targeted to replisomes to prime eukaryotic DNA replication. Mol Cell 2023; 83:2911-2924.e16. [PMID: 37506699 PMCID: PMC10501992 DOI: 10.1016/j.molcel.2023.06.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023]
Abstract
During eukaryotic DNA replication, Pol α-primase generates primers at replication origins to start leading-strand synthesis and every few hundred nucleotides during discontinuous lagging-strand replication. How Pol α-primase is targeted to replication forks to prime DNA synthesis is not fully understood. Here, by determining cryoelectron microscopy (cryo-EM) structures of budding yeast and human replisomes containing Pol α-primase, we reveal a conserved mechanism for the coordination of priming by the replisome. Pol α-primase binds directly to the leading edge of the CMG (CDC45-MCM-GINS) replicative helicase via a complex interaction network. The non-catalytic PRIM2/Pri2 subunit forms two interfaces with CMG that are critical for in vitro DNA replication and yeast cell growth. These interactions position the primase catalytic subunit PRIM1/Pri1 directly above the exit channel for lagging-strand template single-stranded DNA (ssDNA), revealing why priming occurs efficiently only on the lagging-strand template and elucidating a mechanism for Pol α-primase to overcome competition from RPA to initiate primer synthesis.
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Affiliation(s)
- Morgan L Jones
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Valentina Aria
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Yasemin Baris
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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6
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Ramírez Montero D, Sánchez H, van Veen E, van Laar T, Solano B, Diffley JFX, Dekker NH. Nucleotide binding halts diffusion of the eukaryotic replicative helicase during activation. Nat Commun 2023; 14:2082. [PMID: 37059705 PMCID: PMC10104875 DOI: 10.1038/s41467-023-37093-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/02/2023] [Indexed: 04/16/2023] Open
Abstract
The eukaryotic replicative helicase CMG centrally orchestrates the replisome and leads the way at the front of replication forks. Understanding the motion of CMG on the DNA is therefore key to our understanding of DNA replication. In vivo, CMG is assembled and activated through a cell-cycle-regulated mechanism involving 36 polypeptides that has been reconstituted from purified proteins in ensemble biochemical studies. Conversely, single-molecule studies of CMG motion have thus far relied on pre-formed CMG assembled through an unknown mechanism upon overexpression of individual constituents. Here, we report the activation of CMG fully reconstituted from purified yeast proteins and the quantification of its motion at the single-molecule level. We observe that CMG can move on DNA in two ways: by unidirectional translocation and by diffusion. We demonstrate that CMG preferentially exhibits unidirectional translocation in the presence of ATP, whereas it preferentially exhibits diffusive motion in the absence of ATP. We also demonstrate that nucleotide binding halts diffusive CMG independently of DNA melting. Taken together, our findings support a mechanism by which nucleotide binding allows newly assembled CMG to engage with the DNA within its central channel, halting its diffusion and facilitating the initial DNA melting required to initiate DNA replication.
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Affiliation(s)
- Daniel Ramírez Montero
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Humberto Sánchez
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Edo van Veen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Belén Solano
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - John F X Diffley
- Chromosome Replication Laboratory, Francis Crick Institute, London, UK.
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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7
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Minamino M, Bouchoux C, Canal B, Diffley JFX, Uhlmann F. A replication fork determinant for the establishment of sister chromatid cohesion. Cell 2023; 186:837-849.e11. [PMID: 36693376 DOI: 10.1016/j.cell.2022.12.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 11/08/2022] [Accepted: 12/22/2022] [Indexed: 01/24/2023]
Abstract
Concomitant with DNA replication, the chromosomal cohesin complex establishes cohesion between newly replicated sister chromatids. Cohesion establishment requires acetylation of conserved cohesin lysine residues by Eco1 acetyltransferase. Here, we explore how cohesin acetylation is linked to DNA replication. Biochemical reconstitution of replication-coupled cohesin acetylation reveals that transient DNA structures, which form during DNA replication, control the acetylation reaction. As polymerases complete lagging strand replication, strand displacement synthesis produces DNA flaps that are trimmed to result in nicked double-stranded DNA. Both flaps and nicks stimulate cohesin acetylation, while subsequent nick ligation to complete Okazaki fragment maturation terminates the acetylation reaction. A flapped or nicked DNA substrate constitutes a transient molecular clue that directs cohesin acetylation to a window behind the replication fork, next to where cohesin likely entraps both sister chromatids. Our results provide an explanation for how DNA replication is linked to sister chromatid cohesion establishment.
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Affiliation(s)
- Masashi Minamino
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Céline Bouchoux
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Berta Canal
- Chromosome Replication Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - John F X Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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8
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Hu Y, Stillman B. Origins of DNA replication in eukaryotes. Mol Cell 2023; 83:352-372. [PMID: 36640769 PMCID: PMC9898300 DOI: 10.1016/j.molcel.2022.12.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023]
Abstract
Errors occurring during DNA replication can result in inaccurate replication, incomplete replication, or re-replication, resulting in genome instability that can lead to diseases such as cancer or disorders such as autism. A great deal of progress has been made toward understanding the entire process of DNA replication in eukaryotes, including the mechanism of initiation and its control. This review focuses on the current understanding of how the origin recognition complex (ORC) contributes to determining the location of replication initiation in the multiple chromosomes within eukaryotic cells, as well as methods for mapping the location and temporal patterning of DNA replication. Origin specification and configuration vary substantially between eukaryotic species and in some cases co-evolved with gene-silencing mechanisms. We discuss the possibility that centromeres and origins of DNA replication were originally derived from a common element and later separated during evolution.
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Affiliation(s)
- Yixin Hu
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA; Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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9
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Gospodinov A, Dzhokova S, Petrova M, Ugrinova I. Chromatin regulators in DNA replication and genome stability maintenance during S-phase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 135:243-280. [PMID: 37061334 DOI: 10.1016/bs.apcsb.2023.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
The duplication of genetic information is central to life. The replication of genetic information is strictly controlled to ensure that each piece of genomic DNA is copied only once during a cell cycle. Factors that slow or stop replication forks cause replication stress. Replication stress is a major source of genome instability in cancer cells. Multiple control mechanisms facilitate the unimpeded fork progression, prevent fork collapse and coordinate fork repair. Chromatin alterations, caused by histone post-translational modifications and chromatin remodeling, have critical roles in normal replication and in avoiding replication stress and its consequences. This text reviews the chromatin regulators that ensure DNA replication and the proper response to replication stress. We also briefly touch on exploiting replication stress in therapeutic strategies. As chromatin regulators are frequently mutated in cancer, manipulating their activity could provide many possibilities for personalized treatment.
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Affiliation(s)
- Anastas Gospodinov
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
| | - Stefka Dzhokova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Maria Petrova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Iva Ugrinova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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10
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Casas-Delucchi CS, Daza-Martin M, Williams SL, Coster G. The mechanism of replication stalling and recovery within repetitive DNA. Nat Commun 2022; 13:3953. [PMID: 35853874 PMCID: PMC9296464 DOI: 10.1038/s41467-022-31657-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 06/27/2022] [Indexed: 11/09/2022] Open
Abstract
Accurate chromosomal DNA replication is essential to maintain genomic stability. Genetic evidence suggests that certain repetitive sequences impair replication, yet the underlying mechanism is poorly defined. Replication could be directly inhibited by the DNA template or indirectly, for example by DNA-bound proteins. Here, we reconstitute replication of mono-, di- and trinucleotide repeats in vitro using eukaryotic replisomes assembled from purified proteins. We find that structure-prone repeats are sufficient to impair replication. Whilst template unwinding is unaffected, leading strand synthesis is inhibited, leading to fork uncoupling. Synthesis through hairpin-forming repeats is rescued by replisome-intrinsic mechanisms, whereas synthesis of quadruplex-forming repeats requires an extrinsic accessory helicase. DNA-induced fork stalling is mechanistically similar to that induced by leading strand DNA lesions, highlighting structure-prone repeats as an important potential source of replication stress. Thus, we propose that our understanding of the cellular response to replication stress may also be applied to DNA-induced replication stalling.
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Affiliation(s)
- Corella S Casas-Delucchi
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Manuel Daza-Martin
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Sophie L Williams
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Gideon Coster
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK.
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11
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Scherr MJ, Wahab SA, Remus D, Duderstadt KE. Mobile origin-licensing factors confer resistance to conflicts with RNA polymerase. Cell Rep 2022; 38:110531. [PMID: 35320708 PMCID: PMC8961423 DOI: 10.1016/j.celrep.2022.110531] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 12/10/2021] [Accepted: 02/23/2022] [Indexed: 12/30/2022] Open
Abstract
Fundamental to our understanding of chromosome duplication is the idea that replication origins function both as sites where MCM helicases are loaded during the G1 phase and where synthesis begins in S phase. However, the temporal delay between phases exposes the replisome assembly pathway to potential disruption prior to replication. Using multicolor, single-molecule imaging, we systematically study the consequences of encounters between actively transcribing RNA polymerases (RNAPs) and replication initiation intermediates in the context of chromatin. We demonstrate that RNAP can push multiple licensed MCM helicases over long distances with nucleosomes ejected or displaced. Unexpectedly, we observe that MCM helicase loading intermediates also can be repositioned by RNAP and continue origin licensing after encounters with RNAP, providing a web of alternative origin specification pathways. Taken together, our observations reveal a surprising mobility in origin-licensing factors that confers resistance to the complex challenges posed by diverse obstacles encountered on chromosomes. RNA polymerase robustly pushes MCMs without slowing down Nucleosomes are ejected or pushed by MCMs during repositioning RNA polymerase can bypass ORC or activate ORC sliding and OCCM sliding Origin licensing continues after RNA polymerase encounters and relocalization
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Affiliation(s)
- Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Syafiq Abd Wahab
- Memorial Sloan Kettering Cancer Center, Molecular Biology Program, 1275 York Avenue, New York, NY 10065, USA
| | - Dirk Remus
- Memorial Sloan Kettering Cancer Center, Molecular Biology Program, 1275 York Avenue, New York, NY 10065, USA
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Physik Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
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12
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Cheng J, Li N, Huo Y, Dang S, Tye BK, Gao N, Zhai Y. Structural Insight into the MCM double hexamer activation by Dbf4-Cdc7 kinase. Nat Commun 2022; 13:1396. [PMID: 35296675 PMCID: PMC8927117 DOI: 10.1038/s41467-022-29070-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/24/2022] [Indexed: 12/27/2022] Open
Abstract
The Dbf4-dependent kinase Cdc7 (DDK) regulates DNA replication initiation by phosphorylation of the MCM double hexamer (MCM-DH) to promote helicase activation. Here, we determine a series of cryo electron microscopy (cryo-EM) structures of yeast DDK bound to the MCM-DH. These structures, occupied by one or two DDKs, differ primarily in the conformations of the kinase core. The interactions of DDK with the MCM-DH are mediated exclusively by subunit Dbf4 straddling across the hexamer interface on the three N-terminal domains (NTDs) of subunits Mcm2, Mcm6, and Mcm4. This arrangement brings Cdc7 close to its only essential substrate, the N-terminal serine/threonine-rich domain (NSD) of Mcm4. Dbf4 further displaces the NSD from its binding site on Mcm4-NTD, facilitating an immediate targeting of this motif by Cdc7. Moreover, the active center of Cdc7 is occupied by a unique Dbf4 inhibitory loop, which is disengaged when the kinase core assumes wobbling conformations. This study elucidates the versatility of Dbf4 in regulating the ordered multisite phosphorylation of the MCM-DH by Cdc7 kinase during helicase activation.
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Affiliation(s)
- Jiaxuan Cheng
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China.,Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yunjing Huo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Bik-Kwoon Tye
- Institute for Advanced Study, The Hong Kong University of Science & Technology, Hong Kong, China. .,Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China. .,National Biomedical Imaging Center, Peking University, Beijing, 100871, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
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13
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Structural mechanism for the selective phosphorylation of DNA-loaded MCM double hexamers by the Dbf4-dependent kinase. Nat Struct Mol Biol 2022; 29:10-20. [PMID: 34963704 PMCID: PMC8770131 DOI: 10.1038/s41594-021-00698-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/05/2021] [Indexed: 12/04/2022]
Abstract
Loading of the eukaryotic replicative helicase onto replication origins involves two MCM hexamers forming a double hexamer (DH) around duplex DNA. During S phase, helicase activation requires MCM phosphorylation by Dbf4-dependent kinase (DDK), comprising Cdc7 and Dbf4. DDK selectively phosphorylates loaded DHs, but how such fidelity is achieved is unknown. Here, we determine the cryogenic electron microscopy structure of Saccharomyces cerevisiae DDK in the act of phosphorylating a DH. DDK docks onto one MCM ring and phosphorylates the opposed ring. Truncation of the Dbf4 docking domain abrogates DH phosphorylation, yet Cdc7 kinase activity is unaffected. Late origin firing is blocked in response to DNA damage via Dbf4 phosphorylation by the Rad53 checkpoint kinase. DDK phosphorylation by Rad53 impairs DH phosphorylation by blockage of DDK binding to DHs, and also interferes with the Cdc7 active site. Our results explain the structural basis and regulation of the selective phosphorylation of DNA-loaded MCM DHs, which supports bidirectional replication.
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14
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Ellis N, Zhu J, Yagle MK, Yang WC, Huang J, Kwako A, Seidman MM, Matunis MJ. RNF4 Regulates the BLM Helicase in Recovery From Replication Fork Collapse. Front Genet 2021; 12:753535. [PMID: 34868226 PMCID: PMC8633118 DOI: 10.3389/fgene.2021.753535] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/25/2021] [Indexed: 12/01/2022] Open
Abstract
Sumoylation is an important enhancer of responses to DNA replication stress and the SUMO-targeted ubiquitin E3 ligase RNF4 regulates these responses by ubiquitylation of sumoylated DNA damage response factors. The specific targets and functional consequences of RNF4 regulation in response to replication stress, however, have not been fully characterized. Here we demonstrated that RNF4 is required for the restart of DNA replication following prolonged hydroxyurea (HU)-induced replication stress. Contrary to its role in repair of γ-irradiation-induced DNA double-strand breaks (DSBs), our analysis revealed that RNF4 does not significantly impact recognition or repair of replication stress-associated DSBs. Rather, using DNA fiber assays, we found that the firing of new DNA replication origins, which is required for replication restart following prolonged stress, was inhibited in cells depleted of RNF4. We also provided evidence that RNF4 recognizes and ubiquitylates sumoylated Bloom syndrome DNA helicase BLM and thereby promotes its proteosome-mediated turnover at damaged DNA replication forks. Consistent with it being a functionally important RNF4 substrate, co-depletion of BLM rescued defects in the firing of new replication origins observed in cells depleted of RNF4 alone. We concluded that RNF4 acts to remove sumoylated BLM from collapsed DNA replication forks, which is required to facilitate normal resumption of DNA synthesis after prolonged replication fork stalling and collapse.
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Affiliation(s)
- Nathan Ellis
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Jianmei Zhu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Mary K Yagle
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Wei-Chih Yang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Jing Huang
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, United States
| | - Alexander Kwako
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, United States
| | - Michael J Matunis
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
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15
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Guilliam TA. Mechanisms for Maintaining Eukaryotic Replisome Progression in the Presence of DNA Damage. Front Mol Biosci 2021; 8:712971. [PMID: 34295925 PMCID: PMC8290200 DOI: 10.3389/fmolb.2021.712971] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/25/2021] [Indexed: 12/04/2022] Open
Abstract
The eukaryotic replisome coordinates template unwinding and nascent-strand synthesis to drive DNA replication fork progression and complete efficient genome duplication. During its advancement along the parental template, each replisome may encounter an array of obstacles including damaged and structured DNA that impede its progression and threaten genome stability. A number of mechanisms exist to permit replisomes to overcome such obstacles, maintain their progression, and prevent fork collapse. A combination of recent advances in structural, biochemical, and single-molecule approaches have illuminated the architecture of the replisome during unperturbed replication, rationalised the impact of impediments to fork progression, and enhanced our understanding of DNA damage tolerance mechanisms and their regulation. This review focusses on these studies to provide an updated overview of the mechanisms that support replisomes to maintain their progression on an imperfect template.
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Affiliation(s)
- Thomas A. Guilliam
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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16
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Guilliam TA, Yeeles JT. The eukaryotic replisome tolerates leading-strand base damage by replicase switching. EMBO J 2021; 40:e107037. [PMID: 33555053 PMCID: PMC7917549 DOI: 10.15252/embj.2020107037] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/09/2020] [Accepted: 01/07/2021] [Indexed: 01/15/2023] Open
Abstract
The high‐fidelity replicative DNA polymerases, Pol ε and Pol δ, are generally thought to be poorly equipped to replicate damaged DNA. Direct and complete replication of a damaged template therefore typically requires the activity of low‐fidelity translesion synthesis (TLS) polymerases. Here we show that a yeast replisome, reconstituted with purified proteins, is inherently tolerant of the common oxidative lesion thymine glycol (Tg). Surprisingly, leading‐strand Tg was bypassed efficiently in the presence and absence of the TLS machinery. Our data reveal that following helicase–polymerase uncoupling a switch from Pol ε, the canonical leading‐strand replicase, to the lagging‐strand replicase Pol δ, facilitates rapid, efficient and error‐free lesion bypass at physiological nucleotide levels. This replicase switch mechanism also promotes bypass of the unrelated oxidative lesion, 8‐oxoguanine. We propose that replicase switching may promote continued leading‐strand synthesis whenever the replisome encounters leading‐strand damage that is bypassed more efficiently by Pol δ than by Pol ε.
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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 Tp Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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17
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Ding Q, Koren A. Positive and Negative Regulation of DNA Replication Initiation. Trends Genet 2020; 36:868-879. [PMID: 32739030 PMCID: PMC7572746 DOI: 10.1016/j.tig.2020.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/28/2020] [Accepted: 06/30/2020] [Indexed: 12/25/2022]
Abstract
Genomic DNA is replicated every cell cycle by the programmed activation of replication origins at specific times and chromosomal locations. The factors that define the locations of replication origins and their typical activation times in eukaryotic cells are poorly understood. Previous studies highlighted the role of activating factors and epigenetic modifications in regulating replication initiation. Here, we review the role that repressive pathways - and their alleviation - play in establishing the genomic landscape of replication initiation. Several factors mediate this repression, in particular, factors associated with inactive chromatin. Repression can support organized, yet stochastic, replication initiation, and its absence could explain instances of rapid and random replication or re-replication.
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Affiliation(s)
- Qiliang Ding
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Amnon Koren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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18
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Yuan Z, Li H. Molecular mechanisms of eukaryotic origin initiation, replication fork progression, and chromatin maintenance. Biochem J 2020; 477:3499-3525. [PMID: 32970141 PMCID: PMC7574821 DOI: 10.1042/bcj20200065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/29/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022]
Abstract
Eukaryotic DNA replication is a highly dynamic and tightly regulated process. Replication involves several dozens of replication proteins, including the initiators ORC and Cdc6, replicative CMG helicase, DNA polymerase α-primase, leading-strand DNA polymerase ε, and lagging-strand DNA polymerase δ. These proteins work together in a spatially and temporally controlled manner to synthesize new DNA from the parental DNA templates. During DNA replication, epigenetic information imprinted on DNA and histone proteins is also copied to the daughter DNA to maintain the chromatin status. DNA methyltransferase 1 is primarily responsible for copying the parental DNA methylation pattern into the nascent DNA. Epigenetic information encoded in histones is transferred via a more complex and less well-understood process termed replication-couple nucleosome assembly. Here, we summarize the most recent structural and biochemical insights into DNA replication initiation, replication fork elongation, chromatin assembly and maintenance, and related regulatory mechanisms.
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Affiliation(s)
- Zuanning Yuan
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
| | - Huilin Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, U.S.A
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19
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Esquivel-Naranjo EU, Herrera-Estrella A. Strong preference for the integration of transforming DNA via homologous recombination in Trichoderma atroviride. Fungal Biol 2020; 124:854-863. [PMID: 32948273 DOI: 10.1016/j.funbio.2020.07.001] [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: 03/10/2020] [Revised: 06/17/2020] [Accepted: 07/02/2020] [Indexed: 11/15/2022]
Abstract
Trichoderma species play important roles in nature as plant growth promotors and antagonists of phytopathogenic fungi, and are used as models to study photomorphogenesis. Molecular tools have been implemented to manipulate and improve these fungi. However, instability of transformants or very low frequency of homologous recombination has been reported. Here, we report the fate of transforming DNA, demonstrating that it can follow two different fates. When a vector contains sequences also present in the Trichodermaatroviride genome, it mainly integrates by homologous recombination generating stable recombinant strains. In contrast, vectors with no sequence homology to the T. atroviride genome generate unstable transformants, losing the transforming DNA in the first generation of conidia produced without selection where, surprisingly, the vector behaves as autoreplicative. Integration by homologous recombination was demonstrated when transformants were generated with a truncated version of the blr2 gene, resulting in insertional mutants with phenotypes identical to those of knockout mutants. Our results indicate that T. atroviride is highly efficient in integrating DNA by homologous recombination and that plasmid vectors with no sequence homology to the genome are maintained for several generations in T. atroviride if kept under selective pressure even though they lacked fungal autonomous replication sequences.
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Affiliation(s)
- Edgardo Ulises Esquivel-Naranjo
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Querétaro, Querétaro, 76140, Mexico; Laboratorio Nacional de Genómica para La Biodiversidad, CINVESTAV-Irapuato, 36824, rapuato, Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para La Biodiversidad, CINVESTAV-Irapuato, 36824, rapuato, Mexico.
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20
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Deegan TD, Mukherjee PP, Fujisawa R, Polo Rivera C, Labib K. CMG helicase disassembly is controlled by replication fork DNA, replisome components and a ubiquitin threshold. eLife 2020; 9:e60371. [PMID: 32804080 PMCID: PMC7462611 DOI: 10.7554/elife.60371] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/14/2020] [Indexed: 12/20/2022] Open
Abstract
The eukaryotic replisome assembles around the CMG helicase, which stably associates with DNA replication forks throughout elongation. When replication terminates, CMG is ubiquitylated on its Mcm7 subunit and disassembled by the Cdc48/p97 ATPase. Until now, the regulation that restricts CMG ubiquitylation to termination was unknown, as was the mechanism of disassembly. By reconstituting these processes with purified budding yeast proteins, we show that ubiquitylation is tightly repressed throughout elongation by the Y-shaped DNA structure of replication forks. Termination removes the repressive DNA structure, whereupon long K48-linked ubiquitin chains are conjugated to CMG-Mcm7, dependent on multiple replisome components that bind to the ubiquitin ligase SCFDia2. This mechanism pushes CMG beyond a '5-ubiquitin threshold' that is inherent to Cdc48, which specifically unfolds ubiquitylated Mcm7 and thereby disassembles CMG. These findings explain the exquisite regulation of CMG disassembly and provide a general model for the disassembly of ubiquitylated protein complexes by Cdc48.
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Affiliation(s)
- Tom D Deegan
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Progya P Mukherjee
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Cristian Polo Rivera
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Karim Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
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21
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Hennion M, Arbona JM, Lacroix L, Cruaud C, Theulot B, Tallec BL, Proux F, Wu X, Novikova E, Engelen S, Lemainque A, Audit B, Hyrien O. FORK-seq: replication landscape of the Saccharomyces cerevisiae genome by nanopore sequencing. Genome Biol 2020; 21:125. [PMID: 32456659 PMCID: PMC7251829 DOI: 10.1186/s13059-020-02013-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 04/10/2020] [Indexed: 12/17/2022] Open
Abstract
Genome replication mapping methods profile cell populations, masking cell-to-cell heterogeneity. Here, we describe FORK-seq, a nanopore sequencing method to map replication of single DNA molecules at 200-nucleotide resolution. By quantifying BrdU incorporation along pulse-chased replication intermediates from Saccharomyces cerevisiae, we orient 58,651 replication tracks reproducing population-based replication directionality profiles and map 4964 and 4485 individual initiation and termination events, respectively. Although most events cluster at known origins and fork merging zones, 9% and 18% of initiation and termination events, respectively, occur at many locations previously missed. Thus, FORK-seq reveals the full extent of cell-to-cell heterogeneity in DNA replication.
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Affiliation(s)
- Magali Hennion
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France.,Current address: Epigenetics and Cell Fate Center, CNRS, Université de Paris, 35 rue Hélène Brion, Paris, 75013, France
| | - Jean-Michel Arbona
- Université de Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, 69342, France.,Current address: Laboratory of Biology and Modelling of the Cell, Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, Lyon, 69007, France
| | - Laurent Lacroix
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Corinne Cruaud
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de biologie François-Jacob, Genoscope, 2 rue Gaston Crémieux, Evry, 91057, France
| | - Bertrand Theulot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Benoît Le Tallec
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Florence Proux
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Xia Wu
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Elizaveta Novikova
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France
| | - Stefan Engelen
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de biologie François-Jacob, Genoscope, 2 rue Gaston Crémieux, Evry, 91057, France
| | - Arnaud Lemainque
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de biologie François-Jacob, Genoscope, 2 rue Gaston Crémieux, Evry, 91057, France
| | - Benjamin Audit
- Université de Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, 69342, France
| | - Olivier Hyrien
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d'Ulm, Paris, 75005, France.
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22
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Baretić D, Jenkyn-Bedford M, Aria V, Cannone G, Skehel M, Yeeles JTP. Cryo-EM Structure of the Fork Protection Complex Bound to CMG at a Replication Fork. Mol Cell 2020; 78:926-940.e13. [PMID: 32369734 PMCID: PMC7276988 DOI: 10.1016/j.molcel.2020.04.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
The eukaryotic replisome, organized around the Cdc45-MCM-GINS (CMG) helicase, orchestrates chromosome replication. Multiple factors associate directly with CMG, including Ctf4 and the heterotrimeric fork protection complex (Csm3/Tof1 and Mrc1), which has important roles including aiding normal replication rates and stabilizing stalled forks. How these proteins interface with CMG to execute these functions is poorly understood. Here we present 3 to 3.5 Å resolution electron cryomicroscopy (cryo-EM) structures comprising CMG, Ctf4, and the fork protection complex at a replication fork. The structures provide high-resolution views of CMG-DNA interactions, revealing a mechanism for strand separation, and show Csm3/Tof1 “grip” duplex DNA ahead of CMG via a network of interactions important for efficient replication fork pausing. Although Mrc1 was not resolved in our structures, we determine its topology in the replisome by cross-linking mass spectrometry. Collectively, our work reveals how four highly conserved replisome components collaborate with CMG to facilitate replisome progression and maintain genome stability. Cryo-EM structure of Csm3/Tof1 and Ctf4 bound to the eukaryotic CMG helicase Csm3/Tof1 are positioned at the front of the replisome where they grip duplex DNA High-resolution views of CMG-DNA contacts suggest a mechanism for strand separation Mrc1 binds across one side of CMG contacting the front and back of the replisome
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Affiliation(s)
- Domagoj Baretić
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | | | - Valentina Aria
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Giuseppe Cannone
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Mark Skehel
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Joseph T P Yeeles
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK.
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23
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Capturing the dynamics of genome replication on individual ultra-long nanopore sequence reads. Nat Methods 2019; 16:429-436. [PMID: 31011185 DOI: 10.1038/s41592-019-0394-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/18/2019] [Indexed: 12/19/2022]
Abstract
Replication of eukaryotic genomes is highly stochastic, making it difficult to determine the replication dynamics of individual molecules with existing methods. We report a sequencing method for the measurement of replication fork movement on single molecules by detecting nucleotide analog signal currents on extremely long nanopore traces (D-NAscent). Using this method, we detect 5-bromodeoxyuridine (BrdU) incorporated by Saccharomyces cerevisiae to reveal, at a genomic scale and on single molecules, the DNA sequences replicated during a pulse-labeling period. Under conditions of limiting BrdU concentration, D-NAscent detects the differences in BrdU incorporation frequency across individual molecules to reveal the location of active replication origins, fork direction, termination sites, and fork pausing/stalling events. We used sequencing reads of 20-160 kilobases to generate a whole-genome single-molecule map of DNA replication dynamics and discover a class of low-frequency stochastic origins in budding yeast. The D-NAscent software is available at https://github.com/MBoemo/DNAscent.git .
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24
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Deegan TD, Baxter J, Ortiz Bazán MÁ, Yeeles JTP, Labib KPM. Pif1-Family Helicases Support Fork Convergence during DNA Replication Termination in Eukaryotes. Mol Cell 2019; 74:231-244.e9. [PMID: 30850330 PMCID: PMC6477153 DOI: 10.1016/j.molcel.2019.01.040] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/26/2018] [Accepted: 01/29/2019] [Indexed: 01/21/2023]
Abstract
The convergence of two DNA replication forks creates unique problems during DNA replication termination. In E. coli and SV40, the release of torsional strain by type II topoisomerases is critical for converging replisomes to complete DNA synthesis, but the pathways that mediate fork convergence in eukaryotes are unknown. We studied the convergence of reconstituted yeast replication forks that include all core replisome components and both type I and type II topoisomerases. We found that most converging forks stall at a very late stage, indicating a role for additional factors. We showed that the Pif1 and Rrm3 DNA helicases promote efficient fork convergence and completion of DNA synthesis, even in the absence of type II topoisomerase. Furthermore, Rrm3 and Pif1 are also important for termination of plasmid DNA replication in vivo. These findings identify a eukaryotic pathway for DNA replication termination that is distinct from previously characterized prokaryotic mechanisms.
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Affiliation(s)
- Tom D Deegan
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Jonathan Baxter
- Genome Damage and Stability Centre, Department of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - María Ángeles Ortiz Bazán
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Joseph T P Yeeles
- The MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Karim P M Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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25
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Aria V, Yeeles JTP. Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins. Mol Cell 2018; 73:S1097-2765(18)30879-7. [PMID: 30451148 PMCID: PMC6344338 DOI: 10.1016/j.molcel.2018.10.019] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/17/2018] [Accepted: 10/11/2018] [Indexed: 11/29/2022]
Abstract
DNA replication commences at eukaryotic replication origins following assembly and activation of bidirectional CMG helicases. Once activated, CMG unwinds the parental DNA duplex and DNA polymerase α-primase initiates synthesis on both template strands. By utilizing an origin-dependent replication system using purified yeast proteins, we have mapped start sites for leading-strand replication. Synthesis is mostly initiated outside the origin sequence. Strikingly, rightward leading strands are primed left of the origin and vice versa. We show that each leading strand is established from a lagging-strand primer synthesized by the replisome on the opposite side of the origin. Preventing elongation of primers synthesized left of the origin blocked rightward leading strands, demonstrating that replisomes are interdependent for leading-strand synthesis establishment. The mechanism we reveal negates the need for dedicated leading-strand priming and necessitates a crucial role for the lagging-strand polymerase Pol δ in connecting the nascent leading strand with the advancing replisome.
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Affiliation(s)
- Valentina Aria
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Joseph T P Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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26
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Zhai Y, Tye BK. Structure of the MCM2-7 Double Hexamer and Its Implications for the Mechanistic Functions of the Mcm2-7 Complex. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:189-205. [PMID: 29357059 DOI: 10.1007/978-981-10-6955-0_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The eukaryotic minichromosome maintenance 2-7 complex is the core of the inactive MCM replication licensing complex and the catalytic core of the Cdc45-MCM-GINS replicative helicase. The years of effort to determine the structure of parts or the whole of the heterohexameric complex by X-ray crystallography and conventional cryo-EM produced limited success. Modern cryo-EM technology ushered in a new era of structural biology that allowed the determination of the structure of the inactive double hexamer at an unprecedented resolution of 3.8 Å. This review will focus on the fine details observed in the Mcm2-7 double hexameric complex and their implications for the function of the Mcm2-7 hexamer in its different roles during DNA replication.
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Affiliation(s)
- Yuanliang Zhai
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- Institute for Advanced Study, Hong Kong University of Science and Technology, Hong Kong, China
| | - Bik-Kwoon Tye
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
- Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, USA.
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27
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The Initial Response of a Eukaryotic Replisome to DNA Damage. Mol Cell 2018; 70:1067-1080.e12. [PMID: 29944888 PMCID: PMC6024075 DOI: 10.1016/j.molcel.2018.04.022] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/09/2018] [Accepted: 04/26/2018] [Indexed: 01/27/2023]
Abstract
The replisome must overcome DNA damage to ensure complete chromosome replication. Here, we describe the earliest events in this process by reconstituting collisions between a eukaryotic replisome, assembled with purified proteins, and DNA damage. Lagging-strand lesions are bypassed without delay, leaving daughter-strand gaps roughly the size of an Okazaki fragment. In contrast, leading-strand polymerase stalling significantly impacts replication fork progression. We reveal that the core replisome itself can bypass leading-strand damage by re-priming synthesis beyond it. Surprisingly, this restart activity is rare, mainly due to inefficient leading-strand re-priming, rather than single-stranded DNA exposure or primer extension. We find several unanticipated mechanistic distinctions between leading- and lagging-strand priming that we propose control the replisome’s initial response to DNA damage. Notably, leading-strand restart was specifically stimulated by RPA depletion, which can occur under conditions of replication stress. Our results have implications for pathway choice at stalled forks and priming at DNA replication origins. Reconstitution of collisions between a eukaryotic replisome and DNA damage Leading-strand damage specifically causes fork stalling and uncoupling The eukaryotic replisome can re-initiate leading-strands downstream of DNA damage Multiple mechanistic differences exist between leading- and lagging-strand priming
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28
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Bellush JM, Whitehouse I. DNA replication through a chromatin environment. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0287. [PMID: 28847824 DOI: 10.1098/rstb.2016.0287] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2017] [Indexed: 01/03/2023] Open
Abstract
Compaction of the genome into the nuclear space is achieved by wrapping DNA around octameric assemblies of histone proteins to form nucleosomes, the fundamental repeating unit of chromatin. Aside from providing a means by which to fit larger genomes into the cell, chromatinization of DNA is a crucial means by which the cell regulates access to the genome. While the complex role that chromatin plays in gene transcription has been appreciated for a long time, it is now also apparent that crucial aspects of DNA replication are linked to the biology of chromatin. This review will focus on recent advances in our understanding of how the chromatin environment influences key aspects of DNA replication.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- James M Bellush
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.,BCMB Graduate Program, Weill Cornell Medical College, 1300 York Avenue, New York, NY, USA
| | - Iestyn Whitehouse
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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29
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Abid Ali F, Douglas ME, Locke J, Pye VE, Nans A, Diffley JFX, Costa A. Cryo-EM structure of a licensed DNA replication origin. Nat Commun 2017; 8:2241. [PMID: 29269875 PMCID: PMC5740162 DOI: 10.1038/s41467-017-02389-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/24/2017] [Indexed: 11/08/2022] Open
Abstract
Eukaryotic origins of replication are licensed upon loading of the MCM helicase motor onto DNA. ATP hydrolysis by MCM is required for loading and the post-catalytic MCM is an inactive double hexamer that encircles duplex DNA. Origin firing depends on MCM engagement of Cdc45 and GINS to form the CMG holo-helicase. CMG assembly requires several steps including MCM phosphorylation by DDK. To understand origin activation, here we have determined the cryo-EM structures of DNA-bound MCM, either unmodified or phosphorylated, and visualize a phospho-dependent MCM element likely important for Cdc45 recruitment. MCM pore loops touch both the Watson and Crick strands, constraining duplex DNA in a bent configuration. By comparing our new MCM-DNA structure with the structure of CMG-DNA, we suggest how the conformational transition from the loaded, post-catalytic MCM to CMG might promote DNA untwisting and melting at the onset of replication.
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Affiliation(s)
- Ferdos Abid Ali
- Macromolecular Machines Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Max E Douglas
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Julia Locke
- Macromolecular Machines Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Valerie E Pye
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Andrea Nans
- Structural Biology of Cells and Viruses, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - John F X Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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30
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Frigola J, He J, Kinkelin K, Pye VE, Renault L, Douglas ME, Remus D, Cherepanov P, Costa A, Diffley JFX. Cdt1 stabilizes an open MCM ring for helicase loading. Nat Commun 2017; 8:15720. [PMID: 28643783 PMCID: PMC5490006 DOI: 10.1038/ncomms15720] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/24/2017] [Indexed: 11/09/2022] Open
Abstract
ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2-5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC-Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure.
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Affiliation(s)
- Jordi Frigola
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Jun He
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Kerstin Kinkelin
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Valerie E. Pye
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Ludovic Renault
- Macromolecular Machines Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Max E. Douglas
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York
10065, USA
| | - Peter Cherepanov
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
| | - John F. X. Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London
NW1 1AT, UK
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31
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Abstract
The eukaryotic replicative DNA helicase, Mcm2-7, is loaded in inactive form as a double hexameric complex around double-stranded DNA. To ensure that replication origins fire no more than once per S phase, activation of the Mcm2-7 helicase is temporally separated from Mcm2-7 loading in the cell cycle. This 2-step mechanism requires that inactive Mcm2-7 complexes be maintained for variable periods of time in a topologically bound state on chromatin, which may create a steric obstacle to other DNA transactions. We have recently found in the budding yeast, Saccharomyces cerevisiae, that Mcm2-7 double hexamers can respond to collisions with transcription complexes by sliding along the DNA template. Importantly, Mcm2-7 double hexamers remain functional after displacement along DNA and support replication initiation from sites distal to the origin. These results reveal a novel mechanism to specify eukaryotic replication origin sites and to maintain replication origin competence without the need for Mcm2-7 reloading.
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Affiliation(s)
- Charanya Kumar
- a Molecular Biology Program, Memorial Sloan-Kettering Cancer Center , New York , NY , USA
| | - Dirk Remus
- a Molecular Biology Program, Memorial Sloan-Kettering Cancer Center , New York , NY , USA
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32
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Azmi IF, Watanabe S, Maloney MF, Kang S, Belsky JA, MacAlpine DM, Peterson CL, Bell SP. Nucleosomes influence multiple steps during replication initiation. eLife 2017; 6. [PMID: 28322723 PMCID: PMC5400510 DOI: 10.7554/elife.22512] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/20/2017] [Indexed: 12/20/2022] Open
Abstract
Eukaryotic replication origin licensing, activation and timing are influenced by chromatin but a mechanistic understanding is lacking. Using reconstituted nucleosomal DNA replication assays, we assessed the impact of nucleosomes on replication initiation. To generate distinct nucleosomal landscapes, different chromatin-remodeling enzymes (CREs) were used to remodel nucleosomes on origin-DNA templates. Nucleosomal organization influenced two steps of replication initiation: origin licensing and helicase activation. Origin licensing assays showed that local nucleosome positioning enhanced origin specificity and modulated helicase loading by influencing ORC DNA binding. Interestingly, SWI/SNF- and RSC-remodeled nucleosomes were permissive for origin licensing but showed reduced helicase activation. Specific CREs rescued replication of these templates if added prior to helicase activation, indicating a permissive chromatin state must be established during origin licensing to allow efficient origin activation. Our studies show nucleosomes directly modulate origin licensing and activation through distinct mechanisms and provide insights into the regulation of replication initiation by chromatin.
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Affiliation(s)
- Ishara F Azmi
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
| | - Shinya Watanabe
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Michael F Maloney
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
| | - Sukhyun Kang
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States.,Center for Genomic Integrity, Institute for Basic Science, Ulsan, South Korea
| | - Jason A Belsky
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States.,Program in Computational Biology and Bioinformatics, Duke University, Durham, United States
| | - David M MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Stephen P Bell
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
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33
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Abstract
Cellular DNA replication factories depend on ring-shaped hexameric helicases to aid DNA synthesis by processively unzipping the parental DNA helix. Replicative helicases are loaded onto DNA by dedicated initiator, loader, and accessory proteins during the initiation of DNA replication in a tightly regulated, multistep process. We discuss here the molecular choreography of DNA replication initiation across the three domains of life, highlighting similarities and differences in the strategies used to deposit replicative helicases onto DNA and to melt the DNA helix in preparation for replisome assembly. Although initiators and loaders are phylogenetically related, the mechanisms they use for accomplishing similar tasks have diverged considerably and in an unpredictable manner.
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Affiliation(s)
- Franziska Bleichert
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Michael R Botchan
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA.
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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34
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Mcm10: A Dynamic Scaffold at Eukaryotic Replication Forks. Genes (Basel) 2017; 8:genes8020073. [PMID: 28218679 PMCID: PMC5333062 DOI: 10.3390/genes8020073] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/09/2017] [Accepted: 02/09/2017] [Indexed: 12/13/2022] Open
Abstract
To complete the duplication of large genomes efficiently, mechanisms have evolved that coordinate DNA unwinding with DNA synthesis and provide quality control measures prior to cell division. Minichromosome maintenance protein 10 (Mcm10) is a conserved component of the eukaryotic replisome that contributes to this process in multiple ways. Mcm10 promotes the initiation of DNA replication through direct interactions with the cell division cycle 45 (Cdc45)-minichromosome maintenance complex proteins 2-7 (Mcm2-7)-go-ichi-ni-san GINS complex proteins, as well as single- and double-stranded DNA. After origin firing, Mcm10 controls replication fork stability to support elongation, primarily facilitating Okazaki fragment synthesis through recruitment of DNA polymerase-α and proliferating cell nuclear antigen. Based on its multivalent properties, Mcm10 serves as an essential scaffold to promote DNA replication and guard against replication stress. Under pathological conditions, Mcm10 is often dysregulated. Genetic amplification and/or overexpression of MCM10 are common in cancer, and can serve as a strong prognostic marker of poor survival. These findings are compatible with a heightened requirement for Mcm10 in transformed cells to overcome limitations for DNA replication dictated by altered cell cycle control. In this review, we highlight advances in our understanding of when, where and how Mcm10 functions within the replisome to protect against barriers that cause incomplete replication.
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35
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Raspelli E, Falbo L, Costanzo V. Xenopus egg extract to study regulation of genome-wide and locus-specific DNA replication. Genesis 2017; 55. [PMID: 28095613 DOI: 10.1002/dvg.22996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 11/10/2022]
Abstract
Faithful DNA replication, coupled with accurate repair of DNA damage, is essential to maintain genome stability and relies on different DNA metabolism genes. Many of these genes are involved in the assembly of replication origins, in the coordination of DNA repair to protect replication forks progression in the presence of DNA damage and in the replication of repetitive chromatin regions. Some DNA metabolism genes are essential in higher eukaryotes, suggesting the existence of specialized mechanisms of repair and replication in organisms with complex genomes. The impact on cell survival of many of these genes has so far precluded in depth molecular analysis of their function. The cell-free Xenopus laevis egg extract represents an ideal system to overcome survival issues and to facilitate the biochemical study of replication-associated functions of essential proteins in vertebrate organisms. Here, we will discuss how Xenopus egg extracts have been used to study cellular and molecular processes, such as DNA replication and DNA repair. In particular, we will focus on innovative imaging and proteomic-based experimental approaches to characterize the molecular function of a number of essential DNA metabolism factors involved in the duplication of complex vertebrate genomes.
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Affiliation(s)
- Erica Raspelli
- DNA metabolism laboratory, IFOM, The FIRC institute for Molecular Oncology, Milan, Italy
| | - Lucia Falbo
- DNA metabolism laboratory, IFOM, The FIRC institute for Molecular Oncology, Milan, Italy
| | - Vincenzo Costanzo
- DNA metabolism laboratory, IFOM, The FIRC institute for Molecular Oncology, Milan, Italy
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36
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Kurat CF, Yeeles JTP, Patel H, Early A, Diffley JFX. Chromatin Controls DNA Replication Origin Selection, Lagging-Strand Synthesis, and Replication Fork Rates. Mol Cell 2017; 65:117-130. [PMID: 27989438 PMCID: PMC5222724 DOI: 10.1016/j.molcel.2016.11.016] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/17/2016] [Accepted: 11/07/2016] [Indexed: 11/16/2022]
Abstract
The integrity of eukaryotic genomes requires rapid and regulated chromatin replication. How this is accomplished is still poorly understood. Using purified yeast replication proteins and fully chromatinized templates, we have reconstituted this process in vitro. We show that chromatin enforces DNA replication origin specificity by preventing non-specific MCM helicase loading. Helicase activation occurs efficiently in the context of chromatin, but subsequent replisome progression requires the histone chaperone FACT (facilitates chromatin transcription). The FACT-associated Nhp6 protein, the nucleosome remodelers INO80 or ISW1A, and the lysine acetyltransferases Gcn5 and Esa1 each contribute separately to maximum DNA synthesis rates. Chromatin promotes the regular priming of lagging-strand DNA synthesis by facilitating DNA polymerase α function at replication forks. Finally, nucleosomes disrupted during replication are efficiently re-assembled into regular arrays on nascent DNA. Our work defines the minimum requirements for chromatin replication in vitro and shows how multiple chromatin factors might modulate replication fork rates in vivo.
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Affiliation(s)
- Christoph F Kurat
- Clare Hall Laboratory, Francis Crick Institute, South Mimms, Hertfordshire EN6 3LD, UK
| | - Joseph T P Yeeles
- Clare Hall Laboratory, Francis Crick Institute, South Mimms, Hertfordshire EN6 3LD, UK
| | - Harshil Patel
- Lincoln's Inn Fields Laboratory, Francis Crick Institute, London NW1 1AT, UK
| | - Anne Early
- Clare Hall Laboratory, Francis Crick Institute, South Mimms, Hertfordshire EN6 3LD, UK
| | - John F X Diffley
- Clare Hall Laboratory, Francis Crick Institute, South Mimms, Hertfordshire EN6 3LD, UK.
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37
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Kelly T. Historical Perspective of Eukaryotic DNA Replication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:1-41. [PMID: 29357051 DOI: 10.1007/978-981-10-6955-0_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The replication of the genome of a eukaryotic cell is a complex process requiring the ordered assembly of multiprotein replisomes at many chromosomal sites. The process is strictly controlled during the cell cycle to ensure the complete and faithful transmission of genetic information to progeny cells. Our current understanding of the mechanisms of eukaryotic DNA replication has evolved over a period of more than 30 years through the efforts of many investigators. The aim of this perspective is to provide a brief history of the major advances during this period.
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Affiliation(s)
- Thomas Kelly
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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38
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Duncker BP. Mechanisms Governing DDK Regulation of the Initiation of DNA Replication. Genes (Basel) 2016; 8:genes8010003. [PMID: 28025497 PMCID: PMC5294998 DOI: 10.3390/genes8010003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
The budding yeast Dbf4-dependent kinase (DDK) complex—comprised of cell division cycle (Cdc7) kinase and its regulatory subunit dumbbell former 4 (Dbf4)—is required to trigger the initiation of DNA replication through the phosphorylation of multiple minichromosome maintenance complex subunits 2-7 (Mcm2-7). DDK is also a target of the radiation sensitive 53 (Rad53) checkpoint kinase in response to replication stress. Numerous investigations have determined mechanistic details, including the regions of Mcm2, Mcm4, and Mcm6 phosphorylated by DDK, and a number of DDK docking sites. Similarly, the way in which the Rad53 forkhead-associated 1 (FHA1) domain binds to DDK—involving both canonical and non-canonical interactions—has been elucidated. Recent work has revealed mutual promotion of DDK and synthetic lethal with dpb11-1 3 (Sld3) roles. While DDK phosphorylation of Mcm2-7 subunits facilitates their interaction with Sld3 at origins, Sld3 in turn stimulates DDK phosphorylation of Mcm2. Details of a mutually antagonistic relationship between DDK and Rap1-interacting factor 1 (Rif1) have also recently come to light. While Rif1 is able to reverse DDK-mediated Mcm2-7 complex phosphorylation by targeting the protein phosphatase glycogen 7 (Glc7) to origins, there is evidence to suggest that DDK can counteract this activity by binding to and phosphorylating Rif1.
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Affiliation(s)
- Bernard P Duncker
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada.
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39
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Devbhandari S, Jiang J, Kumar C, Whitehouse I, Remus D. Chromatin Constrains the Initiation and Elongation of DNA Replication. Mol Cell 2016; 65:131-141. [PMID: 27989437 DOI: 10.1016/j.molcel.2016.10.035] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/20/2016] [Accepted: 10/27/2016] [Indexed: 02/03/2023]
Abstract
Eukaryotic chromosomal DNA is faithfully replicated in a complex series of cell-cycle-regulated events that are incompletely understood. Here we report the reconstitution of DNA replication free in solution with purified proteins from the budding yeast Saccharomyces cerevisiae. The system recapitulates regulated bidirectional origin activation; synthesis of leading and lagging strands by the three replicative DNA polymerases Pol α, Pol δ, and Pol ε; and canonical maturation of Okazaki fragments into continuous daughter strands. We uncover a dual regulatory role for chromatin during DNA replication: promoting origin dependence and determining Okazaki fragment length by restricting Pol δ progression. This system thus provides a functional platform for the detailed mechanistic analysis of eukaryotic chromosome replication.
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Affiliation(s)
- Sujan Devbhandari
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Weill-Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Jieqing Jiang
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Weill-Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Charanya Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Iestyn Whitehouse
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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40
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Reusswig KU, Zimmermann F, Galanti L, Pfander B. Robust Replication Control Is Generated by Temporal Gaps between Licensing and Firing Phases and Depends on Degradation of Firing Factor Sld2. Cell Rep 2016; 17:556-569. [DOI: 10.1016/j.celrep.2016.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 08/10/2016] [Accepted: 09/02/2016] [Indexed: 10/20/2022] Open
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41
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Abstract
DNA replication origins strikingly differ between eukaryotic species and cell types. Origins are localized and can be highly efficient in budding yeast, are randomly located in early fly and frog embryos, which do not transcribe their genomes, and are clustered in broad (10-100 kb) non-transcribed zones, frequently abutting transcribed genes, in mammalian cells. Nonetheless, in all cases, origins are established during the G1-phase of the cell cycle by the loading of double hexamers of the Mcm 2-7 proteins (MCM DHs), the core of the replicative helicase. MCM DH activation in S-phase leads to origin unwinding, polymerase recruitment, and initiation of bidirectional DNA synthesis. Although MCM DHs are initially loaded at sites defined by the binding of the origin recognition complex (ORC), they ultimately bind chromatin in much greater numbers than ORC and only a fraction are activated in any one S-phase. Data suggest that the multiplicity and functional redundancy of MCM DHs provide robustness to the replication process and affect replication time and that MCM DHs can slide along the DNA and spread over large distances around the ORC. Recent studies further show that MCM DHs are displaced along the DNA by collision with transcription complexes but remain functional for initiation after displacement. Therefore, eukaryotic DNA replication relies on intrinsically mobile and flexible origins, a strategy fundamentally different from bacteria but conserved from yeast to human. These properties of MCM DHs likely contribute to the establishment of broad, intergenic replication initiation zones in higher eukaryotes.
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Affiliation(s)
- Olivier Hyrien
- Institut de Biologie de l'Ecole Normale Superieure (IBENS), Ecole Normale Superieure, PSL Research University, Paris, France
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42
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Fenwick AL, Kliszczak M, Cooper F, Murray J, Sanchez-Pulido L, Twigg SRF, Goriely A, McGowan SJ, Miller KA, Taylor IB, Logan C, Bozdogan S, Danda S, Dixon J, Elsayed SM, Elsobky E, Gardham A, Hoffer MJV, Koopmans M, McDonald-McGinn DM, Santen GWE, Savarirayan R, de Silva D, Vanakker O, Wall SA, Wilson LC, Yuregir OO, Zackai EH, Ponting CP, Jackson AP, Wilkie AOM, Niedzwiedz W, Bicknell LS. Mutations in CDC45, Encoding an Essential Component of the Pre-initiation Complex, Cause Meier-Gorlin Syndrome and Craniosynostosis. Am J Hum Genet 2016; 99:125-38. [PMID: 27374770 PMCID: PMC5005452 DOI: 10.1016/j.ajhg.2016.05.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/09/2016] [Indexed: 11/19/2022] Open
Abstract
DNA replication precisely duplicates the genome to ensure stable inheritance of genetic information. Impaired licensing of origins of replication during the G1 phase of the cell cycle has been implicated in Meier-Gorlin syndrome (MGS), a disorder defined by the triad of short stature, microtia, and a/hypoplastic patellae. Biallelic partial loss-of-function mutations in multiple components of the pre-replication complex (preRC; ORC1, ORC4, ORC6, CDT1, or CDC6) as well as de novo stabilizing mutations in the licensing inhibitor, GMNN, cause MGS. Here we report the identification of mutations in CDC45 in 15 affected individuals from 12 families with MGS and/or craniosynostosis. CDC45 encodes a component of both the pre-initiation (preIC) and CMG helicase complexes, required for initiation of DNA replication origin firing and ongoing DNA synthesis during S-phase itself, respectively, and hence is functionally distinct from previously identified MGS-associated genes. The phenotypes of affected individuals range from syndromic coronal craniosynostosis to severe growth restriction, fulfilling diagnostic criteria for Meier-Gorlin syndrome. All mutations identified were biallelic and included synonymous mutations altering splicing of physiological CDC45 transcripts, as well as amino acid substitutions expected to result in partial loss of function. Functionally, mutations reduce levels of full-length transcripts and protein in subject cells, consistent with partial loss of CDC45 function and a predicted limited rate of DNA replication and cell proliferation. Our findings therefore implicate the preIC as an additional protein complex involved in the etiology of MGS and connect the core cellular machinery of genome replication with growth, chondrogenesis, and cranial suture homeostasis.
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Affiliation(s)
- Aimee L Fenwick
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Maciej Kliszczak
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Fay Cooper
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Jennie Murray
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Luis Sanchez-Pulido
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Stephen R F Twigg
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Anne Goriely
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Simon J McGowan
- Computational Biology Research Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Kerry A Miller
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Indira B Taylor
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Clare Logan
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Sevcan Bozdogan
- Department of Medical Genetics, Mersin University, Mersin, 33343 Cukurova, Turkey
| | - Sumita Danda
- Department of Clinical Genetics, Christian Medical College and Hospital, Vellore, Tamil Nadu 632004, India
| | - Joanne Dixon
- Genetic Health Service NZ-South Island Hub, Christchurch Hospital, Christchurch, Canterbury 8140, New Zealand
| | - Solaf M Elsayed
- Children's Hospital, Ain Shams University, Cairo 11566, Egypt
| | - Ezzat Elsobky
- Children's Hospital, Ain Shams University, Cairo 11566, Egypt
| | - Alice Gardham
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Mariette J V Hoffer
- Department of Clinical Genetics, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Marije Koopmans
- Department of Clinical Genetics, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Donna M McDonald-McGinn
- Clinical Genetics, The Children's Hospital of Philadelphia, 34th & Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Gijs W E Santen
- Department of Clinical Genetics, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Ravi Savarirayan
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Deepthi de Silva
- Department of Physiology, Faculty of Medicine, University of Kelaniya, Ragama, Gampaha GQ 11010, Sri Lanka
| | - Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Steven A Wall
- Craniofacial Unit, Department of Plastic and Reconstructive Surgery, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Louise C Wilson
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Ozge Ozalp Yuregir
- Genetic Diagnosis Center, Adana Numune Training and Research Hospital, Cukurova, Adana, 01170, Turkey
| | - Elaine H Zackai
- Clinical Genetics, The Children's Hospital of Philadelphia, 34th & Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Chris P Ponting
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Andrew P Jackson
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Andrew O M Wilkie
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Craniofacial Unit, Department of Plastic and Reconstructive Surgery, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Wojciech Niedzwiedz
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Louise S Bicknell
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK; Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, Otago 9016, New Zealand.
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43
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Deegan TD, Yeeles JT, Diffley JF. Phosphopeptide binding by Sld3 links Dbf4-dependent kinase to MCM replicative helicase activation. EMBO J 2016; 35:961-73. [PMID: 26912723 PMCID: PMC4864760 DOI: 10.15252/embj.201593552] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
The initiation of eukaryotic DNA replication requires the assembly of active CMG (Cdc45-MCM-GINS) helicases at replication origins by a set of conserved and essential firing factors. This process is controlled during the cell cycle by cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), and in response to DNA damage by the checkpoint kinase Rad53/Chk1. Here we show that Sld3, previously shown to be an essential CDK and Rad53 substrate, is recruited to the inactive MCM double hexamer in a DDK-dependent manner. Sld3 binds specifically to DDK-phosphorylated peptides from two MCM subunits (Mcm4, 6) and then recruits Cdc45. MCM mutants that cannot bind Sld3 or Sld3 mutants that cannot bind phospho-MCM or Cdc45 do not support replication. Moreover, phosphomimicking mutants in Mcm4 and Mcm6 bind Sld3 without DDK and facilitate DDK-independent replication. Thus, Sld3 is an essential "reader" of DDK phosphorylation, integrating signals from three distinct protein kinase pathways to coordinate DNA replication during S phase.
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Affiliation(s)
- Tom D Deegan
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
| | - Joseph Tp Yeeles
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
| | - John Fx Diffley
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
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44
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Douglas ME, Diffley JFX. Recruitment of Mcm10 to Sites of Replication Initiation Requires Direct Binding to the Minichromosome Maintenance (MCM) Complex. J Biol Chem 2016; 291:5879-5888. [PMID: 26719337 PMCID: PMC4786722 DOI: 10.1074/jbc.m115.707802] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 12/28/2015] [Indexed: 01/11/2023] Open
Abstract
Mcm10 is required for the initiation of eukaryotic DNA replication and contributes in some unknown way to the activation of the Cdc45-MCM-GINS (CMG) helicase. How Mcm10 is localized to sites of replication initiation is unclear, as current models indicate that direct binding to minichromosome maintenance (MCM) plays a role, but the details and functional importance of this interaction have not been determined. Here, we show that purified Mcm10 can bind both DNA-bound double hexamers and soluble single hexamers of MCM. The binding of Mcm10 to MCM requires the Mcm10 C terminus. Moreover, the binding site for Mcm10 on MCM includes the Mcm2 and Mcm6 subunits and overlaps that for the loading factor Cdt1. Whether Mcm10 recruitment to replication origins depends on CMG helicase assembly has been unclear. We show that Mcm10 recruitment occurs via two modes: low affinity recruitment in the absence of CMG assembly ("G1-like") and high affinity recruitment when CMG assembly takes place ("S-phase-like"). Mcm10 that cannot bind directly to MCM is defective in both modes of recruitment and is unable to support DNA replication. These findings indicate that Mcm10 is localized to replication initiation sites by directly binding MCM through the Mcm10 C terminus.
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Affiliation(s)
- Max E Douglas
- From The Francis Crick Institute, Clare Hall Laboratory, South Mimms, Hertfordshire EN6 3LD, United Kingdom
| | - John F X Diffley
- From The Francis Crick Institute, Clare Hall Laboratory, South Mimms, Hertfordshire EN6 3LD, United Kingdom.
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45
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Sanuki Y, Kubota Y, Kanemaki MT, Takahashi TS, Mimura S, Takisawa H. RecQ4 promotes the conversion of the pre-initiation complex at a site-specific origin for DNA unwinding in Xenopus egg extracts. Cell Cycle 2015; 14:1010-23. [PMID: 25602506 DOI: 10.1080/15384101.2015.1007003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Eukaryotic DNA replication is initiated through stepwise assembly of evolutionarily conserved replication proteins onto replication origins, but how the origin DNA is unwound during the assembly process remains elusive. Here, we established a site-specific origin on a plasmid DNA, using in vitro replication systems derived from Xenopus egg extracts. We found that the pre-replicative complex (pre-RC) was preferentially assembled in the vicinity of GAL4 DNA-binding sites of the plasmid, depending on the binding of Cdc6 fused with a GAL4 DNA-binding domain in Cdc6-depleted extracts. Subsequent addition of nucleoplasmic S-phase extracts to the GAL4-dependent pre-RC promoted initiation of DNA replication from the origin, and components of the pre-initiation complex (pre-IC) and the replisome were recruited to the origin concomitant with origin unwinding. In this replication system, RecQ4 is dispensable for both recruitment of Cdc45 onto the origin and stable binding of Cdc45 and GINS to the pre-RC assembled plasmid. However, both origin binding of DNA polymerase α and unwinding of DNA were diminished upon depletion of RecQ4 from the extracts. These results suggest that RecQ4 plays an important role in the conversion of pre-ICs into active replisomes requiring the unwinding of origin DNA in vertebrates.
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Affiliation(s)
- Yosuke Sanuki
- a Department of Biological Sciences; Graduate School of Science ; Osaka University ; Toyonaka , Osaka , Japan
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46
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Quan Y, Xia Y, Liu L, Cui J, Li Z, Cao Q, Chen XS, Campbell JL, Lou H. Cell-Cycle-Regulated Interaction between Mcm10 and Double Hexameric Mcm2-7 Is Required for Helicase Splitting and Activation during S Phase. Cell Rep 2015; 13:2576-2586. [PMID: 26686640 DOI: 10.1016/j.celrep.2015.11.018] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 09/22/2015] [Accepted: 11/03/2015] [Indexed: 10/22/2022] Open
Abstract
Mcm2-7 helicase is loaded onto double-stranded origin DNA as an inactive double hexamer (DH) in G1 phase. The mechanisms of Mcm2-7 remodeling that trigger helicase activation in S phase remain unknown. Here, we develop an approach to detect and purify the endogenous DHs directly. Through cellular fractionation, we provide in vivo evidence that DHs are assembled on chromatin in G1 phase and separated during S phase. Interestingly, Mcm10, a robust MCM interactor, co-purifies exclusively with the DHs in the context of chromatin. Deletion of the main interaction domain, Mcm10 C terminus, causes growth and S phase defects, which can be suppressed through Mcm10-MCM fusions. By monitoring the dynamics of MCM DHs, we show a significant delay in DH dissolution during S phase in the Mcm10-MCM interaction-deficient mutants. Therefore, we propose an essential role for Mcm10 in Mcm2-7 remodeling through formation of a cell-cycle-regulated supercomplex with DHs.
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Affiliation(s)
- Yun Quan
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Yisui Xia
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Lu Liu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Jiamin Cui
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Zhen Li
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Qinhong Cao
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China
| | - Xiaojiang S Chen
- Molecular and Computational Biology, USC Norris Cancer Center, and Chemistry Department, University of Southern California, Los Angeles, CA 90089, USA
| | - Judith L Campbell
- Braun Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
| | - Huiqiang Lou
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, 2 Yuan-Ming-Yuan West Road, Beijing 100193, China.
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47
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Hesketh EL, Knight JRP, Wilson RHC, Chong JPJ, Coverley D. Transient association of MCM complex proteins with the nuclear matrix during initiation of mammalian DNA replication. Cell Cycle 2015; 14:333-41. [PMID: 25659032 DOI: 10.4161/15384101.2014.980647] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The minichromosome maintenance complex (MCM2-7) is the putative DNA helicase in eukaryotes, and essential for DNA replication. By applying serial extractions to mammalian cells synchronized by release from quiescence, we reveal dynamic changes to the sub-nuclear compartmentalization of MCM2 as cells pass through late G1 and early S phase, identifying a brief window when MCM2 becomes transiently attached to the nuclear-matrix. The data distinguish 3 states that correspond to loose association with chromatin prior to DNA replication, transient highly stable binding to the nuclear-matrix coincident with initiation, and a post-initiation phase when MCM2 remains tightly associated with chromatin but not the nuclear-matrix. The data suggests that functional MCM complex loading takes place at the nuclear-matrix.
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Affiliation(s)
- Emma L Hesketh
- a Department of Biology ; University of York ; York , UK
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48
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Gros J, Kumar C, Lynch G, Yadav T, Whitehouse I, Remus D. Post-licensing Specification of Eukaryotic Replication Origins by Facilitated Mcm2-7 Sliding along DNA. Mol Cell 2015; 60:797-807. [PMID: 26656162 DOI: 10.1016/j.molcel.2015.10.022] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/28/2015] [Accepted: 10/09/2015] [Indexed: 12/11/2022]
Abstract
Eukaryotic genomes are replicated from many origin sites that are licensed by the loading of the replicative DNA helicase, Mcm2-7. How eukaryotic origin positions are specified remains elusive. Here we show that, contrary to the bacterial paradigm, eukaryotic replication origins are not irrevocably defined by selection of the helicase loading site, but can shift in position after helicase loading. Using purified proteins we show that DNA translocases, including RNA polymerase, can push budding yeast Mcm2-7 double hexamers along DNA. Displaced Mcm2-7 double hexamers support DNA replication initiation distal to the loading site in vitro. Similarly, in yeast cells that are defective for transcription termination, collisions with RNA polymerase induce a redistribution of Mcm2-7 complexes along the chromosomes, resulting in a corresponding shift in DNA replication initiation sites. These results reveal a eukaryotic origin specification mechanism that departs from the classical replicon model, helping eukaryotic cells to negotiate transcription-replication conflict.
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Affiliation(s)
- Julien Gros
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA
| | - Charanya Kumar
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA
| | - Gerard Lynch
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA
| | - Tejas Yadav
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA; Weill-Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Iestyn Whitehouse
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA.
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49
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Perez-Arnaiz P, Bruck I, Kaplan DL. Mcm10 coordinates the timely assembly and activation of the replication fork helicase. Nucleic Acids Res 2015; 44:315-29. [PMID: 26582917 PMCID: PMC4705653 DOI: 10.1093/nar/gkv1260] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/02/2015] [Indexed: 11/12/2022] Open
Abstract
Mcm10 is an essential replication factor that is required for DNA replication in eukaryotes. Two key steps in the initiation of DNA replication are the assembly and activation of Cdc45–Mcm2–7-GINS (CMG) replicative helicase. However, it is not known what coordinates helicase assembly with helicase activation. We show in this manuscript, using purified proteins from budding yeast, that Mcm10 directly interacts with the Mcm2–7 complex and Cdc45. In fact, Mcm10 recruits Cdc45 to Mcm2–7 complex in vitro. To study the role of Mcm10 in more detail in vivo we used an auxin inducible degron in which Mcm10 is degraded upon addition of auxin. We show in this manuscript that Mcm10 is required for the timely recruitment of Cdc45 and GINS recruitment to the Mcm2–7 complex in vivo during early S phase. We also found that Mcm10 stimulates Mcm2 phosphorylation by DDK in vivo and in vitro. These findings indicate that Mcm10 plays a critical role in coupling replicative helicase assembly with helicase activation. Mcm10 is first involved in the recruitment of Cdc45 to the Mcm2–7 complex. After Cdc45–Mcm2–7 complex assembly, Mcm10 promotes origin melting by stimulating DDK phosphorylation of Mcm2, which thereby leads to GINS attachment to Mcm2–7.
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Affiliation(s)
- Patricia Perez-Arnaiz
- Florida State University College of Medicine, Department of Biomedical Sciences, Tallahassee, FL 32306, USA
| | - Irina Bruck
- Florida State University College of Medicine, Department of Biomedical Sciences, Tallahassee, FL 32306, USA
| | - Daniel L Kaplan
- Florida State University College of Medicine, Department of Biomedical Sciences, Tallahassee, FL 32306, USA
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50
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Herrera MC, Tognetti S, Riera A, Zech J, Clarke P, Fernández-Cid A, Speck C. A reconstituted system reveals how activating and inhibitory interactions control DDK dependent assembly of the eukaryotic replicative helicase. Nucleic Acids Res 2015; 43:10238-50. [PMID: 26338774 PMCID: PMC4666391 DOI: 10.1093/nar/gkv881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/22/2015] [Indexed: 11/17/2022] Open
Abstract
During G1-phase of the cell-cycle the replicative MCM2–7 helicase becomes loaded onto DNA into pre-replicative complexes (pre-RCs), resulting in MCM2–7 double-hexamers on DNA. In S-phase, Dbf4-dependent kinase (DDK) and cyclin-dependent-kinase (CDK) direct with the help of a large number of helicase-activation factors the assembly of a Cdc45–MCM2–7–GINS (CMG) complex. However, in the absence of S-phase kinases complex assembly is inhibited, which is unexpected, as the MCM2–7 double-hexamer represents a very large interaction surface. Currently it is unclear what mechanisms restricts complex assembly and how DDK can overcome this inhibition to promote CMG-assembly. We developed an advanced reconstituted-system to study helicase activation in-solution and discovered that individual factors like Sld3 and Sld2 can bind directly to the pre-RC, while Cdc45 cannot. When Sld3 and Sld2 were incubated together with the pre-RC, we observed that competitive interactions restrict complex assembly. DDK stabilizes the Sld3/Sld2–pre-RC complex, but the complex is only short-lived, indicating an anti-cooperative mechanism. Yet, a Sld3/Cdc45–pre-RC can form in the presence of DDK and the addition of Sld2 enhances complex stability. Our results indicate that helicase activation is regulated by competitive and cooperative interactions, which restrict illegitimate complex formation and direct limiting helicase-activation factors into pre-initiation complexes.
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Affiliation(s)
- M Carmen Herrera
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Silvia Tognetti
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Alberto Riera
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Juergen Zech
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Pippa Clarke
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Alejandra Fernández-Cid
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Christian Speck
- DNA Replication Group, Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
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