1
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Dos Santos Á, Rollins DE, Hari-Gupta Y, McArthur H, Du M, Ru SYZ, Pidlisna K, Stranger A, Lorgat F, Lambert D, Brown I, Howland K, Aaron J, Wang L, Ellis PJI, Chew TL, Martin-Fernandez M, Pyne ALB, Toseland CP. Autophagy receptor NDP52 alters DNA conformation to modulate RNA polymerase II transcription. Nat Commun 2023; 14:2855. [PMID: 37202403 PMCID: PMC10195817 DOI: 10.1038/s41467-023-38572-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/09/2023] [Indexed: 05/20/2023] Open
Abstract
NDP52 is an autophagy receptor involved in the recognition and degradation of invading pathogens and damaged organelles. Although NDP52 was first identified in the nucleus and is expressed throughout the cell, to date, there is no clear nuclear functions for NDP52. Here, we use a multidisciplinary approach to characterise the biochemical properties and nuclear roles of NDP52. We find that NDP52 clusters with RNA Polymerase II (RNAPII) at transcription initiation sites and that its overexpression promotes the formation of additional transcriptional clusters. We also show that depletion of NDP52 impacts overall gene expression levels in two model mammalian cells, and that transcription inhibition affects the spatial organisation and molecular dynamics of NDP52 in the nucleus. This directly links NDP52 to a role in RNAPII-dependent transcription. Furthermore, we also show that NDP52 binds specifically and with high affinity to double-stranded DNA (dsDNA) and that this interaction leads to changes in DNA structure in vitro. This, together with our proteomics data indicating enrichment for interactions with nucleosome remodelling proteins and DNA structure regulators, suggests a possible function for NDP52 in chromatin regulation. Overall, here we uncover nuclear roles for NDP52 in gene expression and DNA structure regulation.
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Affiliation(s)
- Ália Dos Santos
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, S10 2RX, UK
- MRC LMB, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Daniel E Rollins
- Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, UK
| | - Yukti Hari-Gupta
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
- MRC LMCB, University College London, Gower Street, London, WC1E 6BT, UK
| | - Hannah McArthur
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Mingxue Du
- Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, UK
| | | | - Kseniia Pidlisna
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Ane Stranger
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Faeeza Lorgat
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, S10 2RX, UK
| | - Danielle Lambert
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, S10 2RX, UK
| | - Ian Brown
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Kevin Howland
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Jesse Aaron
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Lin Wang
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, OX11 0QX, UK
| | - Peter J I Ellis
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Teng-Leong Chew
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Marisa Martin-Fernandez
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, OX11 0QX, UK
| | - Alice L B Pyne
- Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, UK
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2
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Fission Yeast Rho1p-GEFs: From Polarity and Cell Wall Synthesis to Genome Stability. Int J Mol Sci 2022; 23:ijms232213888. [PMID: 36430366 PMCID: PMC9697909 DOI: 10.3390/ijms232213888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Rho1p is a membrane-associated protein that belongs to the Rho family of small GTPases. These proteins coordinate processes such as actin remodelling and polarised secretion to maintain the shape and homeostasis of yeast cells. In response to extracellular stimuli, Rho1p undergoes conformational switching between a guanosine triphosphate (GTP)-bound active state and a guanosine diphosphate (GDP)-bound inactive state. Cycling is improved with guanine nucleotide exchange factor (GEF) activity necessary to activate signalling and GTPase activating protein (GAP) activity required for subsequent signal depletion. This review focuses on fission yeast Rho1p GEFs, Rgf1p, Rgf2p, and Rgf3p that belong to the family of DH-PH domain-containing Dbl-related GEFs. They are multi-domain proteins that detect biological signals that induce or inhibit their catalytic activity over Rho1p. Each of them activates Rho1p in different places and times. Rgf1p acts preferentially during polarised growth. Rgf2p is required for sporulation, and Rgf3p plays an essential function in septum synthesis. In addition, we outline the noncanonical roles of Rho1p-GEFs in genomic instability.
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3
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Doss RM, Xhunga S, Klimczak D, Cameron M, Verlare J, Wolkow TD. Fission yeast Ase1 PRC1 is required for the G 2-microtubule damage response. MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2021; 10:179-188. [PMID: 35097140 PMCID: PMC8798275 DOI: 10.22099/mbrc.2021.41001.1650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Schizosaccharomyces pombe delays entry into mitosis following G2 microtubule damage. This pathway is dependent on Rad26ATRIP, the regulatory subunit of the Rad26ATRIP/Rad3ATR DNA damage response (DDR) complex. However, this G2 microtubule damage response pathway acts independently of the G2 DNA damage checkpoint pathway. To identify other proteins in this G2 microtubule damage pathway, we previously screened a cDNA overexpression library for genes that rescued the sensitivity of rad26Δ cells to the microtubule poison thiabendazole. A partial cDNA fragment encoding only the C-terminal regulatory region of the microtubule bundling protein Ase1 PRC1 was isolated. This fragment lacks the Ase1PRC1 dimerization and microtubule binding domains and retains the conserved C-terminal unstructured regulatory region. Here, we report that ase1Δ cells fail to delay entry into mitosis following G2 microtubule damage. Microscopy revealed that Rad26ATRIP foci localized alongside Ase1PRC1 filaments, although we suggest that this is related to microtubule-dependent double strand break mobility that facilitates homologous recombination events. Indeed, we report that the DNA repair protein Rad52 co-localizes with Rad26ATRIP at these foci, and that localization of Rad26ATRIP to these foci depends on a Rad26ATRIP N-terminal region containing a checkpoint recruitment domain. To our knowledge, this is the first report implicating Ase1PRC1 in regulation of the G2/M transition.
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Affiliation(s)
| | | | | | | | | | - Tom D. Wolkow
- Corresponding Author: Department of Biology, 1420 Austin Bluffs Parkway, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, Tel:+719 255 3663; Fax: +719 255-3047, E. mail:
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4
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Jones CE, Forsburg SL. Monitoring Schizosaccharomyces pombe genome stress by visualizing end-binding protein Ku. Biol Open 2021; 10:bio.054346. [PMID: 33579693 PMCID: PMC7904001 DOI: 10.1242/bio.054346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Studies of genome stability have exploited visualization of fluorescently tagged proteins in live cells to characterize DNA damage, checkpoint, and repair responses. In this report, we describe a new tool for fission yeast, a tagged version of the end-binding protein Pku70 which is part of the KU protein complex. We compare Pku70 localization to other markers upon treatment to various genotoxins, and identify a unique pattern of distribution. Pku70 provides a new tool to define and characterize DNA lesions and the repair response. Summary: The authors describe a fluorescently tagged Ku70 protein to monitor replication stress in live S. pombe cells.
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Affiliation(s)
- Chance E Jones
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Susan L Forsburg
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
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5
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Tatebe H, Lim CT, Konno H, Shiozaki K, Shinohara A, Uchihashi T, Furukohri A. Rad50 zinc hook functions as a constitutive dimerization module interchangeable with SMC hinge. Nat Commun 2020; 11:370. [PMID: 31953386 PMCID: PMC6969161 DOI: 10.1038/s41467-019-14025-0] [Citation(s) in RCA: 21] [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: 05/23/2019] [Accepted: 12/10/2019] [Indexed: 01/11/2023] Open
Abstract
The human Mre11/Rad50 complex is one of the key factors in genome maintenance pathways. Previous nanoscale imaging by atomic force microscopy (AFM) showed that the ring-like structure of the human Mre11/Rad50 complex transiently opens at the zinc hook of Rad50. However, imaging of the human Mre11/Rad50 complex by high-speed AFM shows that the Rad50 coiled-coil arms are consistently bridged by the dimerized hooks while the Mre11/Rad50 ring opens by disconnecting the head domains; resembling other SMC proteins such as cohesin or condensin. These architectural features are conserved in the yeast and bacterial Mre11/Rad50 complexes. Yeast strains harboring the chimeric Mre11/Rad50 complex containing the SMC hinge of bacterial condensin MukB instead of the RAD50 hook properly functions in DNA repair. We propose that the basic role of the Rad50 hook is similar to that of the SMC hinge, which serves as rather stable dimerization interface.
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Affiliation(s)
- Hisashi Tatebe
- Nara Institute of Science and Technology, Graduate School of Biological Sciences, Ikoma, Nara, 630-0192, Japan
| | - Chew Theng Lim
- Nara Institute of Science and Technology, Graduate School of Biological Sciences, Ikoma, Nara, 630-0192, Japan
| | - Hiroki Konno
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Kazuhiro Shiozaki
- Nara Institute of Science and Technology, Graduate School of Biological Sciences, Ikoma, Nara, 630-0192, Japan
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA, 95616, USA
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan.
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787, Japan.
| | - Asako Furukohri
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan.
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6
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Zhurinsky J, Salas-Pino S, Iglesias-Romero AB, Torres-Mendez A, Knapp B, Flor-Parra I, Wang J, Bao K, Jia S, Chang F, Daga RR. Effects of the microtubule nucleator Mto1 on chromosomal movement, DNA repair, and sister chromatid cohesion in fission yeast. Mol Biol Cell 2019; 30:2695-2708. [PMID: 31483748 PMCID: PMC6761766 DOI: 10.1091/mbc.e19-05-0301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/27/2019] [Accepted: 08/30/2019] [Indexed: 11/11/2022] Open
Abstract
Although the function of microtubules (MTs) in chromosomal segregation during mitosis is well characterized, much less is known about the role of MTs in chromosomal functions during interphase. In the fission yeast Schizosaccharomyces pombe, dynamic cytoplasmic MT bundles move chromosomes in an oscillatory manner during interphase via linkages through the nuclear envelope (NE) at the spindle pole body (SPB) and other sites. Mto1 is a cytoplasmic factor that mediates the nucleation and attachment of cytoplasmic MTs to the nucleus. Here, we test the function of these cytoplasmic MTs and Mto1 on DNA repair and recombination during interphase. We find that mto1Δ cells exhibit defects in DNA repair and homologous recombination (HR) and abnormal DNA repair factory dynamics. In these cells, sister chromatids are not properly paired, and binding of Rad21 cohesin subunit along chromosomal arms is reduced. Our findings suggest a model in which cytoplasmic MTs and Mto1 facilitate efficient DNA repair and HR by promoting dynamic chromosomal organization and cohesion in the nucleus.
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Affiliation(s)
- Jacob Zhurinsky
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
| | - Silvia Salas-Pino
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
| | - Ana B. Iglesias-Romero
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
| | - Antonio Torres-Mendez
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
| | - Benjamin Knapp
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Ignacio Flor-Parra
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
| | - Jiyong Wang
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Kehan Bao
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Songtao Jia
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Fred Chang
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Rafael R. Daga
- Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, Seville 41013, Spain
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7
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Pichugin A, Iarovaia OV, Gavrilov A, Sklyar I, Barinova N, Barinov A, Ivashkin E, Caron G, Aoufouchi S, Razin SV, Fest T, Lipinski M, Vassetzky YS. The IGH locus relocalizes to a "recombination compartment" in the perinucleolar region of differentiating B-lymphocytes. Oncotarget 2018; 8:40079-40089. [PMID: 28445143 PMCID: PMC5522243 DOI: 10.18632/oncotarget.16941] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 03/29/2017] [Indexed: 12/22/2022] Open
Abstract
The immunoglobulin heavy chain (IGH) gene loci are subject to specific recombination events during B-cell differentiation including somatic hypermutation and class switch recombination which mark the end of immunoglobulin gene maturation in germinal centers of secondary lymph nodes. These two events rely on the activity of activation-induced cytidine deaminase (AID) which requires DNA double strand breaks be created, a potential danger to the cell. Applying 3D-fluorescence in situ hybridization coupled with immunofluorescence staining to a previously described experimental system recapitulating normal B-cell differentiation ex vivo, we have kinetically analyzed the radial positioning of the two IGH gene loci as well as their proximity with the nucleolus, heterochromatin and γH2AX foci. Our observations are consistent with the proposal that these IGH gene rearrangements take place in a specific perinucleolar “recombination compartment” where AID could be sequestered thus limiting the extent of its potentially deleterious off-target effects.
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Affiliation(s)
- Andrey Pichugin
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Olga V Iarovaia
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Alexey Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Ilya Sklyar
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Natalja Barinova
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Aleksandr Barinov
- LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Evgeny Ivashkin
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Department of Experimental Neurocytology, Research Center of Neurology, Branch of Brain Research, Moscow, Russia
| | - Gersende Caron
- INSERM U1236, CHU de Rennes, Université Rennes 1, Rennes, France
| | - Said Aoufouchi
- UMR8200 CNRS, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Sergey V Razin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Moscow State University, Moscow, Russia
| | - Thierry Fest
- INSERM U1236, CHU de Rennes, Université Rennes 1, Rennes, France
| | - Marc Lipinski
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Yegor S Vassetzky
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Moscow State University, Moscow, Russia
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8
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Chen T, Gomez-Escoda B, Munoz-Garcia J, Babic J, Griscom L, Wu PYJ, Coudreuse D. A drug-compatible and temperature-controlled microfluidic device for live-cell imaging. Open Biol 2017; 6:rsob.160156. [PMID: 27512142 PMCID: PMC5008015 DOI: 10.1098/rsob.160156] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/11/2016] [Indexed: 01/09/2023] Open
Abstract
Monitoring cellular responses to changes in growth conditions and perturbation of targeted pathways is integral to the investigation of biological processes. However, manipulating cells and their environment during live-cell-imaging experiments still represents a major challenge. While the coupling of microfluidics with microscopy has emerged as a powerful solution to this problem, this approach remains severely underexploited. Indeed, most microdevices rely on the polymer polydimethylsiloxane (PDMS), which strongly absorbs a variety of molecules commonly used in cell biology. This effect of the microsystems on the cellular environment hampers our capacity to accurately modulate the composition of the medium and the concentration of specific compounds within the microchips, with implications for the reliability of these experiments. To overcome this critical issue, we developed new PDMS-free microdevices dedicated to live-cell imaging that show no interference with small molecules. They also integrate a module for maintaining precise sample temperature both above and below ambient as well as for rapid temperature shifts. Importantly, changes in medium composition and temperature can be efficiently achieved within the chips while recording cell behaviour by microscopy. Compatible with different model systems, our platforms provide a versatile solution for the dynamic regulation of the cellular environment during live-cell imaging.
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Affiliation(s)
- Tong Chen
- SyntheCell team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Blanca Gomez-Escoda
- Genome Duplication and Maintenance team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Javier Munoz-Garcia
- SyntheCell team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Julien Babic
- SyntheCell team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Laurent Griscom
- SyntheCell team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Pei-Yun Jenny Wu
- Genome Duplication and Maintenance team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
| | - Damien Coudreuse
- SyntheCell team, Institute of Genetics and Development, CNRS UMR 6290, 2 avenue du Pr. Léon Bernard, 35043 Rennes, France
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9
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Manjón E, Edreira T, Muñoz S, Sánchez Y. Rgf1p (Rho1p GEF) is required for double-strand break repair in fission yeast. Nucleic Acids Res 2017; 45:5269-5284. [PMID: 28334931 PMCID: PMC5435928 DOI: 10.1093/nar/gkx176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 03/07/2017] [Indexed: 12/04/2022] Open
Abstract
Rho GTPases are conserved molecules that control cytoskeletal dynamics. These functions are expedited by Rho GEFs that stimulate the release of GDP to enable GTP binding, thereby allowing Rho proteins to initiate intracellular signaling. How Rho GEFs and Rho GTPases protect cells from DNA damage is unknown. Here, we explore the extreme sensitivity of a deletion mutation in the Rho1p exchange factor Rgf1p to the DNA break/inducing antibiotic phleomycin (Phl). The Rgf1p mutant cells are defective in reentry into the cell cycle following the induction of severe DNA damage. This phenotype correlates with the inability of rgf1Δ cells to efficiently repair fragmented chromosomes after Phl treatment. Consistent with this observation Rad11p (ssDNA binding protein, RPA), Rad52p, Rad54p and Rad51p, which facilitate strand invasion in the process of homology-directed repair (HDR), are permanently stacked in Phl-induced foci in rgf1Δ cells. These phenotypes are phenocopied by genetic inhibition of Rho1p. Our data provide evidence that Rgf1p/Rho1p activity positively controls a repair function that confers resistance against the anti-cancer drug Phl.
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Affiliation(s)
- Elvira Manjón
- Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain
| | - Tomás Edreira
- Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain
| | - Sofía Muñoz
- Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain
| | - Yolanda Sánchez
- Instituto de Biología Funcional y Genómica, CSIC. Departamento de Microbiología y Genética, Universidad de Salamanca. C/Zacarías González, s/n. Salamanca, Spain
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10
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Sanchez A, Gadaleta MC, Limbo O, Russell P. Lingering single-strand breaks trigger Rad51-independent homology-directed repair of collapsed replication forks in the polynucleotide kinase/phosphatase mutant of fission yeast. PLoS Genet 2017; 13:e1007013. [PMID: 28922417 PMCID: PMC5626526 DOI: 10.1371/journal.pgen.1007013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 10/03/2017] [Accepted: 09/08/2017] [Indexed: 11/19/2022] Open
Abstract
The DNA repair enzyme polynucleotide kinase/phosphatase (PNKP) protects genome integrity by restoring ligatable 5'-phosphate and 3'-hydroxyl termini at single-strand breaks (SSBs). In humans, PNKP mutations underlie the neurological disease known as MCSZ, but these individuals are not predisposed for cancer, implying effective alternative repair pathways in dividing cells. Homology-directed repair (HDR) of collapsed replication forks was proposed to repair SSBs in PNKP-deficient cells, but the critical HDR protein Rad51 is not required in PNKP-null (pnk1Δ) cells of Schizosaccharomyces pombe. Here, we report that pnk1Δ cells have enhanced requirements for Rad3 (ATR/Mec1) and Chk1 checkpoint kinases, and the multi-BRCT domain protein Brc1 that binds phospho-histone H2A (γH2A) at damaged replication forks. The viability of pnk1Δ cells depends on Mre11 and Ctp1 (CtIP/Sae2) double-strand break (DSB) resection proteins, Rad52 DNA strand annealing protein, Mus81-Eme1 Holliday junction resolvase, and Rqh1 (BLM/WRN/Sgs1) DNA helicase. Coupled with increased sister chromatid recombination and Rad52 repair foci in pnk1Δ cells, these findings indicate that lingering SSBs in pnk1Δ cells trigger Rad51-independent homology-directed repair of collapsed replication forks. From these data, we propose models for HDR-mediated tolerance of persistent SSBs with 3' phosphate in pnk1Δ cells.
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Affiliation(s)
- Arancha Sanchez
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Mariana C. Gadaleta
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Oliver Limbo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Paul Russell
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
- * E-mail:
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11
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Kubota Y, Shimizu S, Yasuhira S, Horiuchi S. SNF2H interacts with XRCC1 and is involved in repair of H2O2-induced DNA damage. DNA Repair (Amst) 2016; 43:69-77. [PMID: 27268481 DOI: 10.1016/j.dnarep.2016.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 11/28/2022]
Abstract
The protein XRCC1 has no inherent enzymatic activity, and is believed to function in base excision repair as a dedicated scaffold component that coordinates other DNA repair factors. Repair foci clearly represent the recruitment and accumulation of DNA repair factors at sites of damage; however, uncertainties remain regarding their organization in the context of nuclear architecture and their biological significance. Here we identified the chromatin remodeling factor SNF2H/SMARCA5 as a novel binding partner of XRCC1, with their interaction dependent on the casein kinase 2-mediated constitutive phosphorylation of XRCC1. The proficiency of repairing H2O2-induced damage was strongly impaired by SNF2H knock-down, and similar impairment was observed with knock-down of both XRCC1 and SNF2H simultaneously, suggesting their role in a common repair pathway. Most SNF2H exists in the nuclear matrix fraction, forming salt extraction-resistant foci-like structures in unchallenged nuclei. Remarkably, damage-induced formation of both PAR and XRCC1 foci depended on SNF2H, and the PAR and XRCC1 foci co-localized with the SNF2H foci. We propose a model in which a base excision repair complex containing damaged chromatin is recruited to specific locations in the nuclear matrix for repair, with this recruitment mediated by XRCC1-SNF2H interaction.
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Affiliation(s)
- Yoshiko Kubota
- Department of Molecular Biochemistry, School of Medicine, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Shiwa, Iwate 028-3694, Japan.
| | - Shinji Shimizu
- Department of Molecular Biochemistry, School of Medicine, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Shiwa, Iwate 028-3694, Japan
| | - Shinji Yasuhira
- Department of Tumor Biology, School of Medicine, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Shiwa, Iwate 028-3694, Japan
| | - Saburo Horiuchi
- Department of Molecular Biochemistry, School of Medicine, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Shiwa, Iwate 028-3694, Japan
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12
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Sánchez A, Russell P. Ku stabilizes replication forks in the absence of Brc1. PLoS One 2015; 10:e0126598. [PMID: 25965521 PMCID: PMC4428774 DOI: 10.1371/journal.pone.0126598] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/05/2015] [Indexed: 11/21/2022] Open
Abstract
DNA replication errors are a major source of genome instability in all organisms. In the fission yeast Schizosaccharomyces pombe, the DNA damage response protein Brc1 binds phospho-histone H2A (γH2A)-marked chromatin during S-phase, but how Brc1 protects genome integrity remains unclear. Here we report that the non-homologous end-joining (NHEJ) protein Ku becomes critical for survival of replication stress in brc1∆ cells. Ku’s protective activity in brc1∆ cells does not involve its canonical NHEJ function or its roles in protecting telomeres or shielding DNA ends from Exo1 exonuclease. In brc1∆ pku80∆ cells, nuclear foci of Rad52 homologous recombination (HR) protein increase and Mus81-Eme1 Holliday junction resolvase becomes critical, indicating increased replication fork instability. Ku’s localization at a ribosomal DNA replication fork barrier associated with frequent replisome-transcriptosome collisions increases in brc1∆ cells and increased collisions correlate with an enhanced requirement for Brc1. These data indicate that Ku stabilizes replication forks in the absence of Brc1.
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Affiliation(s)
- Arancha Sánchez
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paul Russell
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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13
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Nguyen MO, Jalan M, Morrow CA, Osman F, Whitby MC. Recombination occurs within minutes of replication blockage by RTS1 producing restarted forks that are prone to collapse. eLife 2015; 4:e04539. [PMID: 25806683 PMCID: PMC4407270 DOI: 10.7554/elife.04539] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 03/24/2015] [Indexed: 11/13/2022] Open
Abstract
The completion of genome duplication during the cell cycle is threatened by the presence of replication fork barriers (RFBs). Following collision with a RFB, replication proteins can dissociate from the stalled fork (fork collapse) rendering it incapable of further DNA synthesis unless recombination intervenes to restart replication. We use time-lapse microscopy and genetic assays to show that recombination is initiated within ∼ 10 min of replication fork blockage at a site-specific barrier in fission yeast, leading to a restarted fork within ∼ 60 min, which is only prevented/curtailed by the arrival of the opposing replication fork. The restarted fork is susceptible to further collapse causing hyper-recombination downstream of the barrier. Surprisingly, in our system fork restart is unnecessary for maintaining cell viability. Seemingly, the risk of failing to complete replication prior to mitosis is sufficient to warrant the induction of recombination even though it can cause deleterious genetic change.
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Affiliation(s)
- Michael O Nguyen
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Manisha Jalan
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Carl A Morrow
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Fekret Osman
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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14
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Genetic Interaction Landscape Reveals Critical Requirements for Schizosaccharomyces pombe Brc1 in DNA Damage Response Mutants. G3-GENES GENOMES GENETICS 2015; 5:953-62. [PMID: 25795664 PMCID: PMC4426379 DOI: 10.1534/g3.115.017251] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Brc1, which was first identified as a high-copy, allele-specific suppressor of a mutation impairing the Smc5-Smc6 holocomplex in Schizosaccharomyces pombe, protects genome integrity during normal DNA replication and when cells are exposed to toxic compounds that stall or collapse replication forks. The C-terminal tandem BRCT (BRCA1 C-terminus) domain of fission yeast Brc1 docks with phosphorylated histone H2A (γH2A)-marked chromatin formed by ATR/Rad3 checkpoint kinase at arrested and damaged replication forks; however, how Brc1 functions in relation to other genome protection modules remains unclear. Here, an epistatic mini-array profile reveals critical requirements for Brc1 in mutants that are defective in multiple DNA damage response pathways, including checkpoint signaling by Rad3-Rad26/ATR-ATRIP kinase, DNA repair by Smc5-Smc6 holocomplex, replication fork stabilization by Mrc1/claspin and Swi1-Swi3/Timeless-Tipin, and control of ubiquitin-regulated proteolysis by the COP9 signalosome (CSN). Exogenous genotoxins enhance these negative genetic interactions. Rad52 and RPA foci are increased in CSN-defective cells, and loss of γH2A increases genotoxin sensitivity, indicating a critical role for the γH2A-Brc1 module in stabilizing replication forks in CSN-defective cells. A negative genetic interaction with the Nse6 subunit of Smc5-Smc6 holocomplex indicates that the DNA repair functions of Brc1 and Smc5-Smc6 holocomplex are at least partially independent. Rtt107, the Brc1 homolog in Saccharomyces cerevisiae, has a very different pattern of genetic interactions, indicating evolutionary divergence of functions and DNA damage responses.
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15
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Guarino E, Cojoc G, García-Ulloa A, Tolić IM, Kearsey SE. Real-time imaging of DNA damage in yeast cells using ultra-short near-infrared pulsed laser irradiation. PLoS One 2014; 9:e113325. [PMID: 25409521 PMCID: PMC4237433 DOI: 10.1371/journal.pone.0113325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/22/2014] [Indexed: 01/12/2023] Open
Abstract
Analysis of accumulation of repair and checkpoint proteins at repair sites in yeast nuclei has conventionally used chemical agents, ionizing radiation or induction of endonucleases to inflict localized damage. In addition to these methods, similar studies in mammalian cells have used laser irradiation, which has the advantage that damage is inflicted at a specific nuclear region and at a precise time, and this allows accurate kinetic analysis of protein accumulation at DNA damage sites. We show here that it is feasible to use short pulses of near-infrared laser irradiation to inflict DNA damage in subnuclear regions of yeast nuclei by multiphoton absorption. In conjunction with use of fluorescently-tagged proteins, this allows quantitative analysis of protein accumulation at damage sites within seconds of damage induction. PCNA accumulated at damage sites rapidly, such that maximum accumulation was seen approximately 50 s after damage, then levels declined linearly over 200-1000 s after irradiation. RPA accumulated with slower kinetics such that hardly any accumulation was detected within 60 s of irradiation, and levels subsequently increased linearly over the next 900 s, after which levels were approximately constant (up to ca. 2700 s) at the damage site. This approach complements existing methodologies to allow analysis of key damage sensors and chromatin modification changes occurring within seconds of damage inception.
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Affiliation(s)
- Estrella Guarino
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Gheorghe Cojoc
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Iva M. Tolić
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Stephen E. Kearsey
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- * E-mail:
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16
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Castel SE, Ren J, Bhattacharjee S, Chang AY, Sánchez M, Valbuena A, Antequera F, Martienssen RA. Dicer promotes transcription termination at sites of replication stress to maintain genome stability. Cell 2014; 159:572-83. [PMID: 25417108 DOI: 10.1016/j.cell.2014.09.031] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/29/2014] [Accepted: 09/17/2014] [Indexed: 12/12/2022]
Abstract
Nuclear RNAi is an important regulator of transcription and epigenetic modification, but the underlying mechanisms remain elusive. Using a genome-wide approach in the fission yeast S. pombe, we have found that Dcr1, but not other components of the canonical RNAi pathway, promotes the release of Pol II from the 3? end of highly transcribed genes, and, surprisingly, from antisense transcription of rRNA and tRNA genes, which are normally transcribed by Pol I and Pol III. These Dcr1-terminated loci correspond to sites of replication stress and DNA damage, likely resulting from transcription-replication collisions. At the rDNA loci, release of Pol II facilitates DNA replication and prevents homologous recombination, which would otherwise lead to loss of rDNA repeats especially during meiosis. Our results reveal a novel role for Dcr1-mediated transcription termination in genome maintenance and may account for widespread regulation of genome stability by nuclear RNAi in higher eukaryotes.
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Affiliation(s)
- Stephane E Castel
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Jie Ren
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Sonali Bhattacharjee
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - An-Yun Chang
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Molecular and Cellular Biology Program, Stony Brook University, Stony Brook, NY 11794, USA
| | - Mar Sánchez
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Salamanca 37007, Spain
| | - Alberto Valbuena
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Salamanca 37007, Spain
| | - Francisco Antequera
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Salamanca 37007, Spain
| | - Robert A Martienssen
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Molecular and Cellular Biology Program, Stony Brook University, Stony Brook, NY 11794, USA.
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17
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Tai PWL, Zaidi SK, Wu H, Grandy RA, Montecino MM, van Wijnen AJ, Lian JB, Stein GS, Stein JL. The dynamic architectural and epigenetic nuclear landscape: developing the genomic almanac of biology and disease. J Cell Physiol 2014; 229:711-27. [PMID: 24242872 PMCID: PMC3996806 DOI: 10.1002/jcp.24508] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 11/11/2013] [Indexed: 12/31/2022]
Abstract
Compaction of the eukaryotic genome into the confined space of the cell nucleus must occur faithfully throughout each cell cycle to retain gene expression fidelity. For decades, experimental limitations to study the structural organization of the interphase nucleus restricted our understanding of its contributions towards gene regulation and disease. However, within the past few years, our capability to visualize chromosomes in vivo with sophisticated fluorescence microscopy, and to characterize chromosomal regulatory environments via massively parallel sequencing methodologies have drastically changed how we currently understand epigenetic gene control within the context of three-dimensional nuclear structure. The rapid rate at which information on nuclear structure is unfolding brings challenges to compare and contrast recent observations with historic findings. In this review, we discuss experimental breakthroughs that have influenced how we understand and explore the dynamic structure and function of the nucleus, and how we can incorporate historical perspectives with insights acquired from the ever-evolving advances in molecular biology and pathology.
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Affiliation(s)
- Phillip W. L. Tai
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Sayyed K. Zaidi
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Hai Wu
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Rodrigo A. Grandy
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Martin M. Montecino
- Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andres Bello, Santiago, Chile
| | - André J. van Wijnen
- Departments of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN
| | - Jane B. Lian
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Gary S. Stein
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
| | - Janet L. Stein
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT
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18
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Bellini A, Girard PM, Tessier L, Sage E, Francesconi S. Fission yeast Rad52 phosphorylation restrains error prone recombination pathways. PLoS One 2014; 9:e95788. [PMID: 24748152 PMCID: PMC3991707 DOI: 10.1371/journal.pone.0095788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/30/2014] [Indexed: 11/21/2022] Open
Abstract
Rad52 is a key protein in homologous recombination (HR), a DNA repair pathway dedicated to double strand breaks and recovery of blocked or collapsed replication forks. Rad52 allows Rad51 loading on single strand DNA, an event required for strand invasion and D-loop formation. In addition, Rad52 functions also in Rad51 independent pathways because of its ability to promote single strand annealing (SSA) that leads to loss of genetic material and to promote D-loops formation that are cleaved by Mus81 endonuclease. We have previously reported that fission yeast Rad52 is phosphorylated in a Sty1 dependent manner upon oxidative stress and in cells where the early step of HR is impaired because of lack of Rad51. Here we show that Rad52 is also constitutively phosphorylated in mus81 null cells and that Sty1 partially impinges on such phosphorylation. As upon oxidative stress, the Rad52 phosphorylation in rad51 and mus81 null cells appears to be independent of Tel1, Rad3 and Cdc2. Most importantly, we show that mutating serine 365 to glycine (S365G) in Rad52 leads to loss of the constitutive Rad52 phosphorylation observed in cells lacking Rad51 and to partial loss of Rad52 phosphorylation in cells lacking Mus81. Contrariwise, phosphorylation of Rad52-S365G protein is not affected upon oxidative stress. These results indicate that different Rad52 residues are phosphorylated in a Sty1 dependent manner in response to these distinct situations. Analysis of spontaneous HR at direct repeats shows that mutating serine 365 leads to an increase in spontaneous deletion-type recombinants issued from mitotic recombination that are Mus81 dependent. In addition, the recombination rate in the rad52-S365G mutant is further increased by hydroxyurea, a drug to which mutant cells are sensitive.
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Affiliation(s)
- Angela Bellini
- Institut Curie, Centre de Recherche, Orsay, France
- CNRS UMR 3348, Bât. 110, Centre Universitaire, Orsay, France
| | - Pierre-Marie Girard
- Institut Curie, Centre de Recherche, Orsay, France
- CNRS UMR 3348, Bât. 110, Centre Universitaire, Orsay, France
| | - Ludovic Tessier
- Institut Curie, Centre de Recherche, Orsay, France
- CNRS UMR 3348, Bât. 110, Centre Universitaire, Orsay, France
| | - Evelyne Sage
- Institut Curie, Centre de Recherche, Orsay, France
- CNRS UMR 3348, Bât. 110, Centre Universitaire, Orsay, France
| | - Stefania Francesconi
- Institut Curie, Centre de Recherche, Orsay, France
- CNRS UMR 3348, Bât. 110, Centre Universitaire, Orsay, France
- * E-mail:
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19
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Prado F. Genetic instability is prevented by Mrc1-dependent spatio-temporal separation of replicative and repair activities of homologous recombination: homologous recombination tolerates replicative stress by Mrc1-regulated replication and repair activities operating at S and G2 in distinct subnuclear compartments. Bioessays 2014; 36:451-62. [PMID: 24615940 PMCID: PMC4312893 DOI: 10.1002/bies.201300161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Homologous recombination (HR) is required to protect and restart stressed replication forks. Paradoxically, the Mrc1 branch of the S phase checkpoints, which is activated by replicative stress, prevents HR repair at breaks and arrested forks. Indeed, the mechanisms underlying HR can threaten genome integrity if not properly regulated. Thus, understanding how cells avoid genetic instability associated with replicative stress, a hallmark of cancer, is still a challenge. Here I discuss recent results that support a model by which HR responds to replication stress through replicative and repair activities that operate at different stages of the cell cycle (S and G2, respectively) and in distinct subnuclear structures. Remarkably, the replication checkpoint appears to control this scenario by inhibiting the assembly of HR repair centers at stressed forks during S phase, thereby avoiding genetic instability.
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Affiliation(s)
- Félix Prado
- Departamento de Biología Molecular, Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), Seville, Spain
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20
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Muñoz S, Manjón E, García P, Sunnerhagen P, Sánchez Y. The checkpoint-dependent nuclear accumulation of Rho1p exchange factor Rgf1p is important for tolerance to chronic replication stress. Mol Biol Cell 2014; 25:1137-50. [PMID: 24478458 PMCID: PMC3967976 DOI: 10.1091/mbc.e13-11-0689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Guanine nucleotide exchange factors control many aspects of cell morphogenesis by turning on Rho-GTPases. The fission yeast exchange factor Rgf1p (Rho gef1) specifically regulates Rho1p during polarized growth and localizes to cortical sites. Here we report that Rgf1p is relocalized to the cell nucleus during the stalled replication caused by hydroxyurea (HU). Import to the nucleus is mediated by a nuclear localization sequence at the N-terminus of Rgf1p, whereas release into the cytoplasm requires two leucine-rich nuclear export sequences at the C-terminus. Moreover, Rgf1p nuclear accumulation during replication arrest depends on the 14-3-3 chaperone Rad24p and the DNA replication checkpoint kinase Cds1p. Both proteins control the nuclear accumulation of Rgf1p by inhibition of its nuclear export. A mutant, Rgf1p-9A, that substitutes nine serine potential phosphorylation Cds1p sites for alanine fails to accumulate in the nucleus in response to replication stress, and this correlates with a severe defect in survival in the presence of HU. In conclusion, we propose that the regulation of Rgf1p could be part of the mechanism by which Cds1p and Rad24p promote survival in the presence of chronic replication stress. It will be of general interest to understand whether the same is true for homologues of Rgf1p in budding yeast and higher eukaryotes.
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Affiliation(s)
- Sofía Muñoz
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37008 Salamanca, Spain Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Gothenburg, Sweden
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21
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Wolkow TD, Durrenberger LT, Maynard MA, Harrall KK, Hines LM. A comprehensive faculty, staff, and student training program enhances student perceptions of a course-based research experience at a two-year institution. CBE LIFE SCIENCES EDUCATION 2014; 13:724-37. [PMID: 25452494 PMCID: PMC4255358 DOI: 10.1187/cbe.14-03-0056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 05/27/2023]
Abstract
Early research experiences must be made available to all undergraduate students, including those at 2-yr institutions who account for nearly half of America's college students. We report on barriers unique to 2-yr institutions that preclude the success of an early course-based undergraduate research experience (CURE). Using a randomized study design, we evaluated a CURE in equivalent introductory biology courses at a 4-yr institution and a 2-yr institution within the same geographic region. We found that these student populations developed dramatically different impressions of the experience. Students at the 4-yr institution enjoyed the CURE significantly more than the traditional labs. However, students at the 2-yr institution enjoyed the traditional labs significantly more, even though the CURE successfully produced targeted learning gains. On the basis of course evaluations, we enhanced instructor, student, and support staff training and reevaluated this CURE at a different campus of the same 2-yr institution. This time, the students reported that they enjoyed the research experience significantly more than the traditional labs. We conclude that early research experiences can succeed at 2-yr institutions, provided that a comprehensive implementation strategy targeting instructor, student, and support staff training is in place.
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Affiliation(s)
- Thomas D Wolkow
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918
| | - Lisa T Durrenberger
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918
| | - Michael A Maynard
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918
| | - Kylie K Harrall
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918
| | - Lisa M Hines
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918
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22
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Tycon MA, Daddysman MK, Fecko CJ. RNA polymerase II subunits exhibit a broad distribution of macromolecular assembly states in the interchromatin space of cell nuclei. J Phys Chem B 2013; 118:423-33. [PMID: 24354435 DOI: 10.1021/jp4082933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Nearly all cellular processes are enacted by multi-subunit protein complexes, yet the assembly mechanism of most complexes is not well understood. The anthropomorphism "protein recruitment" that is used to describe the concerted binding of proteins to accomplish a specific function conceals significant uncertainty about the underlying physical phenomena and chemical interactions governing the formation of macromolecular complexes. We address this deficiency by investigating the diffusion dynamics of two RNA polymerase II subunits, Rpb3 and Rpb9, in regions of live Drosophila cell nuclei that are devoid of chromatin binding sites. Using FRAP microscopy, we demonstrate that both unengaged subunits are incorporated into a broad distribution of complexes, with sizes ranging from free (unincorporated) proteins to those that have been predicted for fully assembled gene transcription units. In live cells, Rpb3 exhibits regions of stability at both size extremes connected by a continuous distribution of complexes. Corresponding measurements on cellular extracts reveal a distribution that retains peaks at the extremes but not in between, suggesting that partially assembled complexes are less stable. We propose that the broad distribution of macromolecular species allows for mechanistic flexibility in the assembly of transcription complexes.
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Affiliation(s)
- Michael A Tycon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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23
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Chen X, Paudyal SC, Chin RI, You Z. PCNA promotes processive DNA end resection by Exo1. Nucleic Acids Res 2013; 41:9325-38. [PMID: 23939618 PMCID: PMC3814391 DOI: 10.1093/nar/gkt672] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Exo1-mediated resection of DNA double-strand break ends generates 3′ single-stranded DNA overhangs required for homology-based DNA repair and activation of the ATR-dependent checkpoint. Despite its critical importance in inducing the overall DNA damage response, the mechanisms and regulation of the Exo1 resection pathway remain incompletely understood. Here, we identify the ring-shaped DNA clamp PCNA as a new factor in the Exo1 resection pathway. Using mammalian cells, Xenopus nuclear extracts and purified proteins, we show that after DNA damage, PCNA loads onto double-strand breaks and promotes Exo1 damage association through direct interaction with Exo1. By tethering Exo1 to the DNA substrate, PCNA confers processivity to Exo1 in resection. This role of PCNA in DNA resection is analogous to its function in DNA replication where PCNA serves as a processivity co-factor for DNA polymerases.
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Affiliation(s)
- Xiaoqing Chen
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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24
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Schonbrun M, Kolesnikov M, Kupiec M, Weisman R. TORC2 is required to maintain genome stability during S phase in fission yeast. J Biol Chem 2013; 288:19649-60. [PMID: 23703609 DOI: 10.1074/jbc.m113.464974] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA damage can occur due to environmental insults or intrinsic metabolic processes and is a major threat to genome stability. The DNA damage response is composed of a series of well coordinated cellular processes that include activation of the DNA damage checkpoint, transient cell cycle arrest, DNA damage repair, and reentry into the cell cycle. Here we demonstrate that mutant cells defective for TOR complex 2 (TORC2) or the downstream AGC-like kinase, Gad8, are highly sensitive to chronic replication stress but are insensitive to ionizing radiation. We show that in response to replication stress, TORC2 is dispensable for Chk1-mediated cell cycle arrest but is required for the return to cell cycle progression. Rad52 is a DNA repair and recombination protein that forms foci at DNA damage sites and stalled replication forks. TORC2 mutant cells show increased spontaneous nuclear Rad52 foci, particularly during S phase, suggesting that TORC2 protects cells from DNA damage that occurs during normal DNA replication. Consistently, the viability of TORC2-Gad8 mutant cells is dependent on the presence of the homologous recombination pathway and other proteins that are required for replication restart following fork replication stalling. Our findings indicate that TORC2 is required for genome integrity. This may be relevant for the growing amount of evidence implicating TORC2 in cancer development.
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Affiliation(s)
- Miriam Schonbrun
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Israel
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A proteome-wide visual screen identifies fission yeast proteins localizing to DNA double-strand breaks. DNA Repair (Amst) 2013; 12:433-43. [PMID: 23628481 DOI: 10.1016/j.dnarep.2013.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 03/18/2013] [Accepted: 04/03/2013] [Indexed: 11/23/2022]
Abstract
DNA double-strand breaks (DSBs) are a major threat to genome integrity. Proteins involved in DNA damage checkpoint signaling and DSB repair often relocalize and concentrate at DSBs. Here, we used an ORFeome library of the fission yeast Schizosaccharomyces pombe to systematically identify proteins targeted to DSBs. We found 51 proteins that, when expressed from a strong exogenous promoter on the ORFeome plasmids, were able to form a distinct nuclear focus at an HO endonuclease-induced DSB. The majority of these proteins have known connections to DNA damage response, but few have been visualized at a specific DSB before. Among the screen hits, 37 can be detected at DSBs when expressed from native promoters. We classified them according to the focus emergence timing of the endogenously tagged proteins. Eight of these 37 proteins are yet unnamed. We named these eight proteins DNA-break-localizing proteins (Dbls) and performed preliminary functional analysis on two of them, Dbl1 (SPCC2H8.05c) and Dbl2 (SPCC553.01c). We found that Dbl1 and Dbl2 contribute to the normal DSB targeting of checkpoint protein Rad26 (homolog of human ATRIP) and DNA repair helicase Fml1 (homolog of human FANCM), respectively. As the first proteome-wide inventory of DSB-localizing proteins, our screen result will be a useful resource for understanding the mechanisms of eukaryotic DSB response.
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Costes A, Lambert SAE. Homologous recombination as a replication fork escort: fork-protection and recovery. Biomolecules 2012; 3:39-71. [PMID: 24970156 PMCID: PMC4030885 DOI: 10.3390/biom3010039] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/11/2012] [Accepted: 12/11/2012] [Indexed: 01/03/2023] Open
Abstract
Homologous recombination is a universal mechanism that allows DNA repair and ensures the efficiency of DNA replication. The substrate initiating the process of homologous recombination is a single-stranded DNA that promotes a strand exchange reaction resulting in a genetic exchange that promotes genetic diversity and DNA repair. The molecular mechanisms by which homologous recombination repairs a double-strand break have been extensively studied and are now well characterized. However, the mechanisms by which homologous recombination contribute to DNA replication in eukaryotes remains poorly understood. Studies in bacteria have identified multiple roles for the machinery of homologous recombination at replication forks. Here, we review our understanding of the molecular pathways involving the homologous recombination machinery to support the robustness of DNA replication. In addition to its role in fork-recovery and in rebuilding a functional replication fork apparatus, homologous recombination may also act as a fork-protection mechanism. We discuss that some of the fork-escort functions of homologous recombination might be achieved by loading of the recombination machinery at inactivated forks without a need for a strand exchange step; as well as the consequence of such a model for the stability of eukaryotic genomes.
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Affiliation(s)
- Audrey Costes
- Institut Curie, Centre de Recherche, CNRS, UMR3348, Centre Universitaire, Bat110, 91405, Orsay, France.
| | - Sarah A E Lambert
- Institut Curie, Centre de Recherche, CNRS, UMR3348, Centre Universitaire, Bat110, 91405, Orsay, France.
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Bellini A, Girard PM, Lambert S, Tessier L, Sage E, Francesconi S. Stress activated protein kinase pathway modulates homologous recombination in fission yeast. PLoS One 2012; 7:e47987. [PMID: 23118915 PMCID: PMC3485339 DOI: 10.1371/journal.pone.0047987] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 09/19/2012] [Indexed: 12/24/2022] Open
Abstract
Rad52 is a key player in homologous recombination (HR), a DNA repair pathway that is dedicated to double strand breaks repair and recovery of perturbed replication forks. Here we show that fission yeast Rad52 homologue is phosphorylated when S phase cells are exposed to ROS inducers such as ultraviolet A radiation or hydrogen peroxide, but not to ultraviolet C or camptothecin. Phosphorylation does not depend on kinases Chk1, Rad3, Tel1 or Cdc2, but depends on a functional stress activated protein kinase (SAPK) pathway and can be partially prevented by anti-oxidant treatment. Indeed, cells lacking Sty1, the major fission yeast MAP kinase of the SAPK pathway, do not display Rad52 phosphorylation and have UVA induced Rad52 foci that persist longer if compared to wild type cells. In addition, spontaneous intrachromosomal HR is diminished in cells lacking Sty1 and, more precisely, gene conversion is affected. Moreover, HR induced by site-specific arrest of replication forks is twice less efficient in cells that do not express Sty1. Importantly, impairing HR by deletion of the gene encoding the recombinase Rhp51 leads to Sty1 dependent Rad52 phosphorylation. Thus, SAPK pathway impinges on early step of HR through phosphorylation of Rad52 in cells challenged by oxidative stress or lacking Rhp51 and is required to promote spontaneous gene conversion and recovery from blocked replication forks.
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Replication fork collapse and genome instability in a deoxycytidylate deaminase mutant. Mol Cell Biol 2012; 32:4445-54. [PMID: 22927644 DOI: 10.1128/mcb.01062-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ribonucleotide reductase (RNR) and deoxycytidylate deaminase (dCMP deaminase) are pivotal allosteric enzymes required to maintain adequate pools of deoxyribonucleoside triphosphates (dNTPs) for DNA synthesis and repair. Whereas RNR inhibition slows DNA replication and activates checkpoint responses, the effect of dCMP deaminase deficiency is largely unknown. Here, we report that deleting the Schizosaccharomyces pombe dcd1(+) dCMP deaminase gene (SPBC2G2.13c) increases dCTP ∼30-fold and decreases dTTP ∼4-fold. In contrast to the robust growth of a Saccharomyces cerevisiae dcd1Δ mutant, fission yeast dcd1Δ cells delay cell cycle progression in early S phase and are sensitive to multiple DNA-damaging agents, indicating impaired DNA replication and repair. DNA content profiling of dcd1Δ cells differs from an RNR-deficient mutant. Dcd1 deficiency activates genome integrity checkpoints enforced by Rad3 (ATR), Cds1 (Chk2), and Chk1 and creates critical requirements for proteins involved in recovery from replication fork collapse, including the γH2AX-binding protein Brc1 and Mus81 Holliday junction resolvase. These effects correlate with increased nuclear foci of the single-stranded DNA binding protein RPA and the homologous recombination repair protein Rad52. Moreover, Brc1 suppresses spontaneous mutagenesis in dcd1Δ cells. We propose that replication forks stall and collapse in dcd1Δ cells, burdening DNA damage and checkpoint responses to maintain genome integrity.
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Crespan E, Czabany T, Maga G, Hübscher U. Microhomology-mediated DNA strand annealing and elongation by human DNA polymerases λ and β on normal and repetitive DNA sequences. Nucleic Acids Res 2012; 40:5577-90. [PMID: 22373917 PMCID: PMC3384310 DOI: 10.1093/nar/gks186] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
'Classical' non-homologous end joining (NHEJ), dependent on the Ku70/80 and the DNA ligase IV/XRCC4 complexes, is essential for the repair of DNA double-strand breaks. Eukaryotic cells possess also an alternative microhomology-mediated end-joining (MMEJ) mechanism, which is independent from Ku and DNA ligase 4/XRCC4. The components of the MMEJ machinery are still largely unknown. Family X DNA polymerases (pols) are involved in the classical NHEJ pathway. We have compared in this work, the ability of human family X DNA pols β, λ and μ, to promote the MMEJ of different model templates with terminal microhomology regions. Our results reveal that DNA pol λ and DNA ligase I are sufficient to promote efficient MMEJ repair of broken DNA ends in vitro, and this in the absence of auxiliary factors. However, DNA pol β, not λ, was more efficient in promoting MMEJ of DNA ends containing the (CAG)n triplet repeat sequence of the human Huntingtin gene, leading to triplet expansion. The checkpoint complex Rad9/Hus1/Rad1 promoted end joining by DNA pol λ on non-repetitive sequences, while it limited triplet expansion by DNA pol β. We propose a possible novel role of DNA pol β in MMEJ, promoting (CAG)n triplet repeats instability.
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Affiliation(s)
- Emmanuele Crespan
- Institute of Molecular Genetics IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy
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Tanae K, Horiuchi T, Matsuo Y, Katayama S, Kawamukai M. Histone chaperone Asf1 plays an essential role in maintaining genomic stability in fission yeast. PLoS One 2012; 7:e30472. [PMID: 22291963 PMCID: PMC3266922 DOI: 10.1371/journal.pone.0030472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 12/20/2011] [Indexed: 01/28/2023] Open
Abstract
The histone H3-H4 chaperone Asf1 is involved in chromatin assembly (or disassembly), histone exchange, regulation of transcription, and chromatin silencing in several organisms. To investigate the essential functions of Asf1 in Schizosaccharomyces pombe, asf1-ts mutants were constructed by random mutagenesis using PCR. One mutant (asf1-33(ts)) was mated with mutants in 77 different kinase genes to identify synthetic lethal combinations. The asf1-33 mutant required the DNA damage checkpoint factors Chk1 and Rad3 for its survival at the restrictive temperature. Chk1, but not Cds1, was phosphorylated in the asf1-33 mutant at the restrictive temperature, indicating that the DNA damage checkpoint was activated in the asf1-33 mutant. DNA damage occured in the asf1-33 mutant, with degradation of the chromosomal DNA observed through pulse-field gel electrophoresis and the formation of Rad22 foci. Sensitivity to micrococcal nuclease in the asf1-33 mutant was increased compared to the asf1+ strain at the restrictive temperature, suggesting that asf1 mutations also caused a defect in overall chromatin structure. The Asf1-33 mutant protein was mislocalized and incapable of binding histones. Furthermore, histone H3 levels at the centromeric outer repeat region were decreased in the asf1-33 mutant and heterochromatin structure was impaired. Finally, sim3, which encodes a CenH3 histone chaperone, was identified as a strong suppressor of the asf1-33 mutant. Taken together, these results clearly indicate that Asf1 plays an essential role in maintaining genomic stability in S. pombe.
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Affiliation(s)
- Katsuhiro Tanae
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Tomitaka Horiuchi
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Yuzy Matsuo
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Satoshi Katayama
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Makoto Kawamukai
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
- * E-mail:
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Maki K, Inoue T, Onaka A, Hashizume H, Somete N, Kobayashi Y, Murakami S, Shigaki C, Takahashi TS, Masukata H, Nakagawa T. Abundance of prereplicative complexes (Pre-RCs) facilitates recombinational repair under replication stress in fission yeast. J Biol Chem 2011; 286:41701-41710. [PMID: 21971174 DOI: 10.1074/jbc.m111.285619] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mcm2-7 complexes are loaded onto chromatin with the aid of Cdt1 and Cdc18/Cdc6 and form prereplicative complexes (pre-RCs) at multiple sites on each chromosome. Pre-RCs are essential for DNA replication and surviving replication stress. However, the mechanism by which pre-RCs contribute to surviving replication stress is largely unknown. Here, we isolated the fission yeast mcm6-S1 mutant that was hypersensitive to methyl methanesulfonate (MMS) and camptothecin (CPT), both of which cause forks to collapse. The mcm6-S1 mutation impaired the interaction with Cdt1 and decreased the binding of minichromosome maintenance (MCM) proteins to replication origins. Overexpression of Cdt1 restored MCM binding and suppressed the sensitivity to MMS and CPT, suggesting that the Cdt1-Mcm6 interaction is important for the assembly of pre-RCs and the repair of collapsed forks. MMS-induced Chk1 phosphorylation and Rad22/Rad52 focus formation occurred normally, whereas cells containing Rhp54/Rad54 foci, which are involved in DNA strand exchange and dissociation of the joint molecules, were increased. Remarkably, G(1) phase extension through deletion of an S phase cyclin, Cig2, as well as Cdt1 overexpression restored pre-RC assembly and suppressed Rhp54 accumulation. A cdc18 mutation also caused hypersensitivity to MMS and CPT and accumulation of Rhp54 foci. These data suggest that an abundance of pre-RCs facilitates a late step in the recombinational repair of collapsed forks in the following S phase.
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Affiliation(s)
- Kentaro Maki
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takahiro Inoue
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Atsushi Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hiroko Hashizume
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Naoko Somete
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yuko Kobayashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Shigefumi Murakami
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Chikako Shigaki
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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32
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Sheltzer JM, Blank HM, Pfau SJ, Tange Y, George BM, Humpton TJ, Brito IL, Hiraoka Y, Niwa O, Amon A. Aneuploidy drives genomic instability in yeast. Science 2011; 333:1026-30. [PMID: 21852501 PMCID: PMC3278960 DOI: 10.1126/science.1206412] [Citation(s) in RCA: 299] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Aneuploidy decreases cellular fitness, yet it is also associated with cancer, a disease of enhanced proliferative capacity. To investigate one mechanism by which aneuploidy could contribute to tumorigenesis, we examined the effects of aneuploidy on genomic stability. We analyzed 13 budding yeast strains that carry extra copies of single chromosomes and found that all aneuploid strains exhibited one or more forms of genomic instability. Most strains displayed increased chromosome loss and mitotic recombination, as well as defective DNA damage repair. Aneuploid fission yeast strains also exhibited defects in mitotic recombination. Aneuploidy-induced genomic instability could facilitate the development of genetic alterations that drive malignant growth in cancer.
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Affiliation(s)
- Jason M. Sheltzer
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Heidi M. Blank
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sarah J. Pfau
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yoshie Tange
- Graduate School of Frontier Biosciences, Osaka University 1–3 Yamadaoka, Suita 565-0871, Japan
| | - Benson M. George
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Timothy J. Humpton
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ilana L. Brito
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University 1–3 Yamadaoka, Suita 565-0871, Japan
- Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Osami Niwa
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Angelika Amon
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Sofueva S, Osman F, Lorenz A, Steinacher R, Castagnetti S, Ledesma J, Whitby MC. Ultrafine anaphase bridges, broken DNA and illegitimate recombination induced by a replication fork barrier. Nucleic Acids Res 2011; 39:6568-84. [PMID: 21576223 PMCID: PMC3159475 DOI: 10.1093/nar/gkr340] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Most DNA double-strand breaks (DSBs) in S- and G2-phase cells are repaired accurately by Rad51-dependent sister chromatid recombination. However, a minority give rise to gross chromosome rearrangements (GCRs), which can result in disease/death. What determines whether a DSB is repaired accurately or inaccurately is currently unclear. We provide evidence that suggests that perturbing replication by a non-programmed protein-DNA replication fork barrier results in the persistence of replication intermediates (most likely regions of unreplicated DNA) into mitosis, which results in anaphase bridge formation and ultimately to DNA breakage. However, unlike previously characterised replication-associated DSBs, these breaks are repaired mainly by Rad51-independent processes such as single-strand annealing, and are therefore prone to generate GCRs. These data highlight how a replication-associated DSB can be predisposed to give rise to genome rearrangements in eukaryotes.
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Affiliation(s)
- Sevil Sofueva
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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Zaratiegui M, Vaughn MW, Irvine DV, Goto D, Watt S, Bähler J, Arcangioli B, Martienssen RA. CENP-B preserves genome integrity at replication forks paused by retrotransposon LTR. Nature 2010; 469:112-5. [PMID: 21151105 PMCID: PMC3057531 DOI: 10.1038/nature09608] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 10/22/2010] [Indexed: 11/25/2022]
Abstract
Centromere-binding protein B (CENP-B) is a widely conserved DNA binding factor associated with heterochromatin and centromeric satellite repeats1. In fission yeast, CENP-B homologs have been shown to silence Long Terminal Repeat (LTR) retrotransposons by recruiting histone deacetylases2. However, CENP-B factors also have unexplained roles in DNA replication3, 4. Here, we show that a molecular function of CENP-B is to promote replication fork progression through the LTR. Mutants have increased genomic instability caused by replication fork blockage that depends on the DNA binding factor Switch Activating Protein 1 (Sap1), which is directly recruited by the LTR. The loss of Sap1-dependent barrier activity allows the unhindered progression of the replication fork, but results in rearrangements deleterious to the retrotransposon. We conclude that retrotransposons influence replication polarity through recruitment of Sap1 and transposition near replication fork blocks, while CENP-B counteracts this activity and promotes fork stability. Our results may account for the role of LTR in fragile sites, and for the association of CENP-B with pericentromeric heterochromatin and tandem satellite repeats.
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Affiliation(s)
- Mikel Zaratiegui
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
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35
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Shermoen AW, McCleland ML, O'Farrell PH. Developmental control of late replication and S phase length. Curr Biol 2010; 20:2067-77. [PMID: 21074439 DOI: 10.1016/j.cub.2010.10.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 10/05/2010] [Accepted: 10/07/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND Fast, early embryonic cell cycles have correspondingly fast S phases. In early Drosophila embryos, forks starting from closely spaced origins replicate the whole genome in 3.4 min, ten times faster than in embryonic cycle 14 and a hundred times faster than in a wing disc. It is not known how S phase duration is regulated. Here we examined prolongation of embryonic S phases, its coupling to development, and its relationship to the appearance of heterochromatin. RESULTS Imaging of fluorescent nucleotide incorporation and GFP-PCNA gave exquisite time resolution of S phase events. In the early S phases, satellite sequences replicated rapidly despite a compact chromatin structure. In S phases 11-13, a delay in satellite replication emerged in sync with modest and progressive prolongation of S phase. In S phase 14, major and distinct delays ordered the replication of satellites into a sequence that occupied much of S phase. This onset of late replication required transcription. Satellites only accumulated abundant heterochromatin protein 1 (HP1) after replicating in S phase 14. By cycle 15, satellites clustered in a compact HP1-positive mass, but replication occurred at decondensed foci at the surface of this mass. CONCLUSIONS The slowing of S phase is an active process, not a titration of maternal replication machinery. Most sequences continue to replicate rapidly in successive cycles, but increasing delays in the replication of satellite sequences extend S phase. Although called constitutively heterochromatic, satellites acquire the distinctive features of heterochromatin, compaction, late replication, HP1 binding, and aggregation at the chromocenter, in successive steps coordinated with developmental progress.
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Affiliation(s)
- Antony W Shermoen
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94143-2200, USA
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Cavero S, Limbo O, Russell P. Critical functions of Rpa3/Ssb3 in S-phase DNA damage responses in fission yeast. PLoS Genet 2010; 6:e1001138. [PMID: 20885790 PMCID: PMC2944793 DOI: 10.1371/journal.pgen.1001138] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 08/24/2010] [Indexed: 11/24/2022] Open
Abstract
Replication Protein A (RPA) is a heterotrimeric, single-stranded DNA (ssDNA)–binding complex required for DNA replication and repair, homologous recombination, DNA damage checkpoint signaling, and telomere maintenance. Whilst the larger RPA subunits, Rpa1 and Rpa2, have essential interactions with ssDNA, the molecular functions of the smallest subunit Rpa3 are unknown. Here, we investigate the Rpa3 ortholog Ssb3 in Schizosaccharomyces pombe and find that it is dispensable for cell viability, checkpoint signaling, RPA foci formation, and meiosis. However, increased spontaneous Rad11Rpa1 and Rad22Rad52 nuclear foci in ssb3Δ cells indicate genome maintenance defects. Moreover, Ssb3 is required for resistance to genotoxins that disrupt DNA replication. Genetic interaction studies indicate that Ssb3 has a close functional relationship with the Mms1-Mms22 protein complex, which is required for survival after DNA damage in S-phase, and with the mitotic functions of Mus81-Eme1 Holliday junction resolvase that is required for recovery from replication fork collapse. From these studies we propose that Ssb3 plays a critical role in mediating RPA functions that are required for repair or tolerance of DNA lesions in S-phase. Rpa3 orthologs in humans and other species may have a similar function. Proteins that bind single-stranded DNA (ssDNA) are essential for DNA replication, most types of DNA repair including homologous recombination, DNA damage signaling, and maintenance of telomeres. In eukaryotes, the most ubiquitous and abundant ssDNA binding protein is Replication Protein A (RPA), a 3-subunit protein complex consisting of large (Rpa1), medium (Rpa2), and small (Rpa3) subunits. Rpa1 and Rpa2 directly bind ssDNA, whilst the function of Rpa3 is largely unknown. Here, we discover that in fission yeast a 2-subunit complex of Rpa1 and Rpa2 is sufficient for the essential DNA replication function of RPA and its role in homologous recombination repair of double-strand breaks. Rpa3 is not required for these functions, but it is needed for survival of many types of DNA damage that stall or collapse replication forks. Genetic studies indicate close functional links between the Rpa3-dependent activities of RPA, the repair of collapsed replication forks by Mus81-Eme1 Holliday junction resolvase, and the newly discovered Mms1-Mms22 protein complex that is essential for resistance to genotoxins that disrupt DNA replication.
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Affiliation(s)
- Santiago Cavero
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Oliver Limbo
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paul Russell
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Genome-wide mapping of nuclear mitochondrial DNA sequences links DNA replication origins to chromosomal double-strand break formation in Schizosaccharomyces pombe. Genome Res 2010; 20:1250-61. [PMID: 20688779 DOI: 10.1101/gr.104513.109] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chromosomal double-strand breaks (DSBs) threaten genome integrity and repair of these lesions is often mutagenic. How and where DSBs are formed is a major question conveniently addressed in simple model organisms like yeast. NUMTs, nuclear DNA sequences of mitochondrial origin, are present in most eukaryotic genomes and probably result from the capture of mitochondrial DNA (mtDNA) fragments into chromosomal breaks. NUMT formation is ongoing and was reported to cause de novo human genetic diseases. Study of NUMTs is likely to contribute to the understanding of naturally occurring chromosomal breaks. We show that Schizosaccharomyces pombe NUMTs are exclusively located in noncoding regions with no preference for gene promoters and, when located into promoters, do not affect gene transcription level. Strikingly, most noncoding regions comprising NUMTs are also associated with a DNA replication origin (ORI). Chromatin immunoprecipitation experiments revealed that chromosomal NUMTs are probably not acting as ORI on their own but that mtDNA insertions occurred directly next to ORIs, suggesting that these loci may be prone to DSB formation. Accordingly, induction of excessive DNA replication origin firing, a phenomenon often associated with human tumor formation, resulted in frequent nucleotide deletion events within ORI3001 subtelomeric chromosomal locus, illustrating a novel aspect of DNA replication-driven genomic instability. How mtDNA is fragmented is another important issue that we addressed by sequencing experimentally induced NUMTs. This highlighted regions of S. pombe mtDNA prone to breaking. Together with an analysis of human NUMTs, we propose that these fragile sites in mtDNA may correspond to replication pause sites.
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38
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Fission yeast Hsk1 (Cdc7) kinase is required after replication initiation for induced mutagenesis and proper response to DNA alkylation damage. Genetics 2010; 185:39-53. [PMID: 20176980 DOI: 10.1534/genetics.109.112284] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genome stability in fission yeast requires the conserved S-phase kinase Hsk1 (Cdc7) and its partner Dfp1 (Dbf4). In addition to their established function in the initiation of DNA replication, we show that these proteins are important in maintaining genome integrity later in S phase and G2. hsk1 cells suffer increased rates of mitotic recombination and require recombination proteins for survival. Both hsk1 and dfp1 mutants are acutely sensitive to alkylation damage yet defective in induced mutagenesis. Hsk1 and Dfp1 are associated with the chromatin even after S phase, and normal response to MMS damage correlates with the maintenance of intact Dfp1 on chromatin. A screen for MMS-sensitive mutants identified a novel truncation allele, rad35 (dfp1-(1-519)), as well as alleles of other damage-associated genes. Although Hsk1-Dfp1 functions with the Swi1-Swi3 fork protection complex, it also acts independently of the FPC to promote DNA repair. We conclude that Hsk1-Dfp1 kinase functions post-initiation to maintain replication fork stability, an activity potentially mediated by the C terminus of Dfp1.
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DNA damage responses in skin biology—Implications in tumor prevention and aging acceleration. J Dermatol Sci 2009; 56:76-81. [DOI: 10.1016/j.jdermsci.2009.09.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 09/04/2009] [Accepted: 09/08/2009] [Indexed: 01/28/2023]
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Abstract
Controlling the loading of Rad51 onto DNA is important for governing when and how homologous recombination is used. Here we use a combination of genetic assays and indirect immunofluorescence to show that the F-box DNA helicase (Fbh1) functions in direct opposition to the Rad52 orthologue Rad22 to curb Rad51 loading onto DNA in fission yeast. Surprisingly, this activity is unnecessary for limiting spontaneous direct-repeat recombination. Instead it appears to play an important role in preventing recombination when replication forks are blocked and/or broken. When overexpressed, Fbh1 specifically reduces replication fork block-induced recombination, as well as the number of Rad51 nuclear foci that are induced by replicative stress. These abilities are dependent on its DNA helicase/translocase activity, suggesting that Fbh1 exerts its control on recombination by acting as a Rad51 disruptase. In accord with this, overexpression of Fbh1 also suppresses the high levels of recombinant formation and Rad51 accumulation at a site-specific replication fork barrier in a strain lacking the Rad51 disruptase Srs2. Similarly overexpression of Srs2 suppresses replication fork block-induced gene conversion events in an fbh1Delta mutant, although an inability to suppress deletion events suggests that Fbh1 has a distinct functionality, which is not readily substituted by Srs2.
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Balakrishnan L, Brandt PD, Lindsey-Boltz LA, Sancar A, Bambara RA. Long patch base excision repair proceeds via coordinated stimulation of the multienzyme DNA repair complex. J Biol Chem 2009; 284:15158-72. [PMID: 19329425 DOI: 10.1074/jbc.m109.000505] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Base excision repair, a major repair pathway in mammalian cells, is responsible for correcting DNA base damage and maintaining genomic integrity. Recent reports show that the Rad9-Rad1-Hus1 complex (9-1-1) stimulates enzymes proposed to perform a long patch-base excision repair sub-pathway (LP-BER), including DNA glycosylases, apurinic/apyrimidinic endonuclease 1 (APE1), DNA polymerase beta (pol beta), flap endonuclease 1 (FEN1), and DNA ligase I (LigI). However, 9-1-1 was found to produce minimal stimulation of FEN1 and LigI in the context of a complete reconstitution of LP-BER. We show here that pol beta is a robust stimulator of FEN1 and a moderate stimulator of LigI. Apparently, there is a maximum possible stimulation of these two proteins such that after responding to pol beta or another protein in the repair complex, only a small additional response to 9-1-1 is allowed. The 9-1-1 sliding clamp structure must serve primarily to coordinate enzyme actions rather than enhancing rate. Significantly, stimulation by the polymerase involves interaction of primer terminus-bound pol beta with FEN1 and LigI. This observation provides compelling evidence that the proposed LP-BER pathway is actually employed in cells. Moreover, this pathway has been proposed to function by sequential enzyme actions in a "hit and run" mechanism. Our results imply that this mechanism is still carried out, but in the context of a multienzyme complex that remains structurally intact during the repair process.
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Affiliation(s)
- Lata Balakrishnan
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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Tdp1 protects against oxidative DNA damage in non-dividing fission yeast. EMBO J 2009; 28:632-40. [PMID: 19197239 DOI: 10.1038/emboj.2009.9] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 01/02/2009] [Indexed: 11/08/2022] Open
Abstract
In humans, a mutation in the tyrosyl-DNA phosphodiesterase (Tdp1) is responsible for the recessively inherited syndrome spinocerebellar ataxia with axonal neuropathy (SCAN1). Tdp1 is a well-conserved DNA repair enzyme, which processes modified 3' phospho-DNA adducts in vitro. Here, we report that in the yeast Schizosaccharomyces pombe, tdp1 mutant cells progressively accumulate DNA damage and rapidly lose viability in a physiological G0/quiescent state. Remarkably, this effect is independent of topoisomerase I function. Moreover, we provide evidence that Tdp1, with the polynucleotide kinase (Pnk1), processes the same naturally occurring 3'-ends, produced from oxidative DNA damage in G0. We also found that one half of the dead cells lose their nuclear DNA. Nuclear DNA degradation is genetically programmed and mainly depends on the two DNA damage checkpoint responses, ATM/Tel1 and ATR/Rad3, reminiscent to programmed cell death. Diminishing the respiration rate or treating cells with a low concentration of antioxidants rescues the quiescent tdp1 mutant cells. These findings suggest that mitochondrial respiration causes neuronal cell death in the SCAN1 syndrome and in other neurological disorders.
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The Schizosaccharomyces pombe Pfh1p DNA helicase is essential for the maintenance of nuclear and mitochondrial DNA. Mol Cell Biol 2008; 28:6594-608. [PMID: 18725402 DOI: 10.1128/mcb.00191-08] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Schizosaccharomyces pombe Pfh1p is an essential member of the Pif family of 5'-3' DNA helicases. The two Saccharomyces cerevisiae homologs, Pif1p and Rrm3p, function in nuclear DNA replication, telomere length regulation, and mitochondrial genome integrity. We demonstrate here the existence of multiple Pfh1p isoforms that localized to either nuclei or mitochondria. The catalytic activity of Pfh1p was essential in both cellular compartments. The absence of nuclear Pfh1p resulted in G(2) arrest and accumulation of DNA damage foci, a finding suggestive of an essential role in DNA replication. Exogenous DNA damage resulted in localization of Pfh1p to DNA damage foci, suggesting that nuclear Pfh1p also functions in DNA repair. The absence of mitochondrial Pfh1p caused rapid depletion of mitochondrial DNA. Despite localization to nuclei and mitochondria in S. pombe, neither of the S. cerevisiae homologs, nor human PIF1, suppressed the lethality of pfh1Delta cells. However, the essential nuclear function of Pfh1p could be supplied by Rrm3p. Expression of Rrm3p suppressed the accumulation of DNA damage foci but not the hydroxyurea sensitivity of cells depleted of nuclear Pfh1p. Together, these data demonstrate that Pfh1p has essential roles in the replication of both nuclear and mitochondrial DNA.
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Radiation induction of delayed recombination in Schizosaccharomyces pombe. DNA Repair (Amst) 2008; 7:1250-61. [PMID: 18547878 DOI: 10.1016/j.dnarep.2008.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 02/15/2008] [Accepted: 04/05/2008] [Indexed: 11/24/2022]
Abstract
Ionizing radiation is known to induce delayed chromosome and gene mutations in the descendants of the irradiated tissue culture cells. Molecular mechanisms of such delayed mutations are yet to be elucidated, since high genomic complexity of mammalian cells makes it difficult to analyze. We now tested radiation induction of delayed recombination in the fission yeast Schizosaccharomyces pombe by monitoring the frequency of homologous recombination after X-irradiation. A reporter with 200 bp tandem repeats went through spontaneous recombination at a frequency of 1.0 x 10(-4), and the frequency increased dose-dependently to around 10 x 10(-4) at 500 Gy of X-irradiation. Although the repair of initial DNA damage was thought to be completed before the restart of cell division cycle, the elevation of the recombination frequency persisted for 8-10 cell generations after irradiation (delayed recombination). The delayed recombination suggests that descendants of the irradiated cells keep a memory of the initial DNA damage which upregulates recombination machinery for 8-10 generations even in the absence of DNA double-strand breaks (DSBs). Since radical scavengers were ineffective in inhibiting the delayed recombination, a memory by continuous production of DNA damaging agents such as reactive oxygen species (ROS) was excluded. Recombination was induced in trans in a reporter on chromosome III by a DNA DSB at a site on chromosome I, suggesting the untargeted nature of delayed recombination. Interestingly, Rad22 foci persisted in the X-irradiated population in parallel with the elevation of the recombination frequency. These results suggest that the epigenetic damage memory induced by DNA DSB upregulates untargeted and delayed recombination in S. pombe.
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A DNA polymerase alpha accessory protein, Mcl1, is required for propagation of centromere structures in fission yeast. PLoS One 2008; 3:e2221. [PMID: 18493607 PMCID: PMC2376062 DOI: 10.1371/journal.pone.0002221] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 04/02/2008] [Indexed: 11/19/2022] Open
Abstract
Specialized chromatin exists at centromeres and must be precisely transmitted during DNA replication. The mechanisms involved in the propagation of these structures remain elusive. Fission yeast centromeres are composed of two chromatin domains: the central CENP-ACnp1 kinetochore domain and flanking heterochromatin domains. Here we show that fission yeast Mcl1, a DNA polymerase α (Polα) accessory protein, is critical for maintenance of centromeric chromatin. In a screen for mutants that alleviate both central domain and outer repeat silencing, we isolated several cos mutants, of which cos1 is allelic to mcl1. The mcl1-101 mutation causes reduced CENP-ACnp1 in the central domain and an aberrant increase in histone acetylation in both domains. These phenotypes are also observed in a mutant of swi7+, which encodes a catalytic subunit of Polα. Mcl1 forms S-phase-specific nuclear foci, which colocalize with those of PCNA and Polα. These results suggest that Mcl1 and Polα are required for propagation of centromere chromatin structures during DNA replication.
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Díaz-Cuervo H, Bueno A. Cds1 controls the release of Cdc14-like phosphatase Flp1 from the nucleolus to drive full activation of the checkpoint response to replication stress in fission yeast. Mol Biol Cell 2008; 19:2488-99. [PMID: 18385517 DOI: 10.1091/mbc.e07-08-0737] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Cdc14p-like phosphatase Flp1p (also known as Clp1p) is regulated by cell cycle-dependent changes in its subcellular localization. Flp1p is restricted to the nucleolus and spindle pole body until prophase, when it is dispersed throughout the nucleus, mitotic spindle, and medial ring. Once released, Flp1p antagonizes Cdc2p/cyclin activity by reverting Cdc2p-phosphorylation sites on Cdc25p. On replication stress, ataxia-telangiectasia mutated/ATM/Rad3-related kinase Rad3p activates Cds1p, which phosphorylates key proteins ensuring the stability of stalled DNA replication forks. Here, we show that replication stress induces changes in the subcellular localization of Flp1p in a checkpoint-dependent manner. Active Cds1p checkpoint kinase is required to release Flp1p into the nucleus. Consistently, a Flp1p mutant (flp1-9A) lacking all potential Cds1p phosphorylation sites fails to relocate in response to replication blocks and, similarly to cells lacking flp1 (Deltaflp1), presents defects in checkpoint response to replication stress. Deltaflp1 cells accumulate reduced levels of a less active Cds1p kinase in hydroxyurea (HU), indicating that nuclear Flp1p regulates Cds1p full activation. Consistently, Deltaflp1 and flp1-9A have an increased percentage of Rad22p-recombination foci during HU treatment. Together, our data show that by releasing Flp1p into the nucleus Cds1p checkpoint kinase modulates its own full activation during replication stress.
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Affiliation(s)
- Helena Díaz-Cuervo
- Instituto de Biología Molecular y Celular del Cáncer, Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, 37007 Salamanca, Spain
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Gembka A, Toueille M, Smirnova E, Poltz R, Ferrari E, Villani G, Hübscher U. The checkpoint clamp, Rad9-Rad1-Hus1 complex, preferentially stimulates the activity of apurinic/apyrimidinic endonuclease 1 and DNA polymerase beta in long patch base excision repair. Nucleic Acids Res 2007; 35:2596-608. [PMID: 17426133 PMCID: PMC1885638 DOI: 10.1093/nar/gkl1139] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Growing evidence suggests that the Rad9-Rad1-Hus1 complex (the 9-1-1 complex), besides its functions in DNA damage sensing and signaling pathways, plays also a direct role in various DNA repair processes. Recent studies have demonstrated that the 9-1-1 complex physically and functionally interacts with several components of the base excision repair (BER) machinery namely DNA polymerase β (Pol β), flap endonuclease 1 (Fen 1), DNA ligase I (Lig I) and the MutY homologue of Schizosaccharomyces pombe. In this work, we found for the first time that the 9-1-1 complex interacts in vitro and in vivo with the apurinic/apyrimidinic endonuclease 1 (APE 1), an early component of BER, and can stimulate its AP-endonuclease activity. Moreover, we show that the 9-1-1 complex possesses a stimulatory effect on long patch base excision repair (LP-BER) reconstituted in vitro. The enhancement of LP-BER activity is due to the specific stimulation of the two early components of the repair machinery, namely APE 1 and Pol β, suggesting a hierarchy of interactions between the 9-1-1 complex and the BER proteins acting in the repairosome. Overall, our results indicate that the 9-1-1 complex is directly involved in LP-BER, thus providing a possible link between DNA damage checkpoints and BER.
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Affiliation(s)
- Agnieszka Gembka
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Magali Toueille
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Ekaterina Smirnova
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Rainer Poltz
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Elena Ferrari
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Giuseppe Villani
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
| | - Ulrich Hübscher
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland and Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 Route de Narbonne, 31077 Toulouse cedex, France
- *To whom correspondence should be addressed 01 635 54 72/7101 635 68 40
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Guan X, Bai H, Shi G, Theriot CA, Hazra TK, Mitra S, Lu AL. The human checkpoint sensor Rad9-Rad1-Hus1 interacts with and stimulates NEIL1 glycosylase. Nucleic Acids Res 2007; 35:2463-72. [PMID: 17395641 PMCID: PMC1885643 DOI: 10.1093/nar/gkm075] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The checkpoint protein Rad9/Rad1/Hus1 heterotrimer (the 9-1-1 complex) is structurally similar to the proliferating cell nuclear antigen sliding clamp and has been proposed to sense DNA damage that leads to cell cycle arrest or apoptosis. Human (h) NEIL1 DNA glycosylase, an ortholog of bacterial Nei/Fpg, is involved in repairing oxidatively damaged DNA bases. In this study, we show that hNEIL1 interacts with hRad9, hRad1 and hHus1 as individual proteins and as a complex. Residues 290–350 of hNEIL1 are important for the 9-1-1 association. A significant fraction of the hNEIL1 nuclear foci co-localize with hRad9 foci in hydrogen peroxide treated cells. Human NEIL1 DNA glycosylase activity is significantly stimulated by hHus1, hRad1, hRad9 separately and the 9-1-1 complex. Thus, the 9-1-1 complex at the lesion sites serves as both a damage sensor to activate checkpoint control and a component of base excision repair.
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Affiliation(s)
- Xin Guan
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Haibo Bai
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Guoli Shi
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Corey A. Theriot
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tapas K. Hazra
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sankar Mitra
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - A-Lien Lu
- Department of Biochemistry and Molecular Biology and Greenebaum Cancer Center, School of Medicine, University of Maryland, Baltimore, MD 21201, USA and Sealy Center for Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- *To whom correspondence should be addressed +1-410-706-4356+1-410-706-1787
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Boerckel J, Walker D, Ahmed S. The Caenorhabditis elegans Rad17 homolog HPR-17 is required for telomere replication. Genetics 2007; 176:703-9. [PMID: 17339221 PMCID: PMC1893056 DOI: 10.1534/genetics.106.070201] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Subunits of the Rad9/Rad1/Hus1 (9-1-1) proliferating cell nuclear antigen (PNCA)-like sliding clamp are required for DNA damage responses and telomerase-mediated telomere replication in the nematode Caenorhabditis elegans. PCNA sliding clamps are loaded onto DNA by a replication factor C (RFC) clamp loader. The C. elegans Rad17 RFC clamp loader homolog, hpr-17, functions in the same pathway as the 9-1-1 complex with regard to both the DNA damage response and telomerase-mediated telomere elongation. Thus, hpr-17 defines an RFC-like complex that facilitates telomerase activity in vivo in C. elegans.
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Affiliation(s)
- Julie Boerckel
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA
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Meister P, Taddei A, Ponti A, Baldacci G, Gasser SM. Replication foci dynamics: replication patterns are modulated by S-phase checkpoint kinases in fission yeast. EMBO J 2007; 26:1315-26. [PMID: 17304223 PMCID: PMC1817620 DOI: 10.1038/sj.emboj.7601538] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 12/11/2006] [Indexed: 12/22/2022] Open
Abstract
Although the molecular enzymology of DNA replication is well characterised, how and why it occurs in discrete nuclear foci is unclear. Using fission yeast, we show that replication takes place in a limited number of replication foci, whose distribution changes with progression through S phase. These sites define replication factories which contain on average 14 replication forks. We show for the first time that entire foci are mobile, able both to fuse and re-segregate. These foci form distinguishable patterns during S phase, whose succession is reproducible, defining early-, mid- and late-S phase. In wild-type cells, this same temporal sequence can be detected in the presence of hydroxyurea (HU), despite the reduced rate of replication. In cells lacking the intra-S checkpoint kinase Cds1, replication factories dismantle on HU. Intriguingly, even in the absence of DNA damage, the replication foci in cds1 cells assume a novel distribution that is not present in wild-type cells, arguing that Cds1 kinase activity contributes to the spatio-temporal organisation of replication during normal cell growth.
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Affiliation(s)
- Peter Meister
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- UMR2027, CNRS/Institut Curie, Bâtiment 110, Centre Universitaire, Orsay Cedex, France
| | - Angela Taddei
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- UMR218, CNRS/Institut Curie, 26 rue d'Ulm, Paris, France
| | - Aaron Ponti
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Giuseppe Baldacci
- UMR2027, CNRS/Institut Curie, Bâtiment 110, Centre Universitaire, Orsay Cedex, France
- These authors contributed equally to this work
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- These authors contributed equally to this work
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. Tel.: +41 61 697 7255; Fax +41 61 697 6862; E-mail:
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