1
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Downs JA, Gasser SM. Chromatin remodeling and spatial concerns in DNA double-strand break repair. Curr Opin Cell Biol 2024; 90:102405. [PMID: 39083951 DOI: 10.1016/j.ceb.2024.102405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/07/2024] [Accepted: 07/11/2024] [Indexed: 08/02/2024]
Abstract
The substrate for the repair of DNA damage in living cells is not DNA but chromatin. Chromatin bears a range of modifications, which in turn bind ligands that compact or open chromatin structure, and determine its spatial organization within the nucleus. In some cases, RNA in the form of RNA:DNA hybrids or R-loops modulates DNA accessibility. Each of these parameters can favor particular pathways of repair. Chromatin or nucleosome remodelers are key regulators of chromatin structure, and a number of remodeling complexes are implicated in DNA repair. We cover novel insights into the impact of chromatin structure, nuclear organization, R-loop formation, nuclear actin, and nucleosome remodelers in DNA double-strand break repair, focusing on factors that alter repair functional upon ablation.
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Affiliation(s)
- Jessica A Downs
- Epigenetics and Genome Stability Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Susan M Gasser
- ISREC Foundation, and University of Lausanne, Agora Cancer Research Center, Rue du Bugnon 25a, 1005 Lausanne, Switzerland.
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2
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Wanat JJ, McCann JJ, Tingey M, Atkins J, Merlino CO, Lee-Soety JY. Yeast Npl3 regulates replicative senescence outside of TERRA R-loop resolution and co-transcriptional processing. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2024:1-21. [PMID: 38976968 DOI: 10.1080/15257770.2024.2374023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 06/20/2024] [Indexed: 07/10/2024]
Abstract
Eukaryotic cells without telomerase experience progressively shorter telomeres with each round of cell division until cell cycle arrest is initiated, leading to replicative senescence. When yeast TLC1, which encodes the RNA template of telomerase, is deleted, senescence is accompanied by increased expression of TERRA (non-coding telomere repeat-containing RNA). Deletion of Npl3, an RNA-processing protein with telomere maintenance functions, accelerates senescence in tlc1Δ cells and significantly increases TERRA levels. Using genetic approaches, we set out to determine how Npl3 is involved in regulating TERRA expression and maintaining telomere homeostasis. Even though Npl3 regulates hyperrecombination, we found that Npl3 does not help resolve RNA:DNA hybrids formed during TERRA synthesis in the same way as RNase H1 and H2. Furthermore, Rad52 is still required for cells to escape senescence by telomere recombination in the absence of Npl3. Npl3 also works separately from the THO/TREX pathway for processing nascent RNA for nuclear export. However, deleting Dot1, a histone methyltransferase involved in tethering telomeres to the nuclear periphery, rescued the accelerated senescence phenotype of npl3Δ cells. Thus, our study suggests that Npl3 plays an additional role in regulating cellular senescence outside of RNA:DNA hybrid resolution and co-transcriptional processing.
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Affiliation(s)
- Jennifer J Wanat
- Department of Biology, Washington College, Chestertown, Maryland, USA
| | - Jennifer J McCann
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Mark Tingey
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Jessica Atkins
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Corinne O Merlino
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Julia Y Lee-Soety
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
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3
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Rivard RS, Chang YC, Ragland RL, Thu YM, Kassab M, Mandal RS, Van Riper SK, Kulej K, Higgins L, Markowski TM, Shang D, Hedberg J, Erber L, Garcia B, Chen Y, Bielinsky AK, Brown EJ. Improved detection of DNA replication fork-associated proteins. Cell Rep 2024; 43:114178. [PMID: 38703364 DOI: 10.1016/j.celrep.2024.114178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 03/06/2024] [Accepted: 04/16/2024] [Indexed: 05/06/2024] Open
Abstract
Innovative methods to retrieve proteins associated with actively replicating DNA have provided a glimpse into the molecular dynamics of replication fork stalling. We report that a combination of density-based replisome enrichment by isolating proteins on nascent DNA (iPOND2) and label-free quantitative mass spectrometry (iPOND2-DRIPPER) substantially increases both replication factor yields and the dynamic range of protein quantification. Replication protein abundance in retrieved nascent DNA is elevated up to 300-fold over post-replicative controls, and recruitment of replication stress factors upon fork stalling is observed at similar levels. The increased sensitivity of iPOND2-DRIPPER permits direct measurement of ubiquitination events without intervening retrieval of diglycine tryptic fragments of ubiquitin. Using this approach, we find that stalled replisomes stimulate the recruitment of a diverse cohort of DNA repair factors, including those associated with poly-K63-ubiquitination. Finally, we uncover the temporally controlled association of stalled replisomes with nuclear pore complex components and nuclear cytoskeleton networks.
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Affiliation(s)
- Rebecca S Rivard
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ya-Chu Chang
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Ryan L Ragland
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yee-Mon Thu
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Muzaffer Kassab
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahul Shubhra Mandal
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Susan K Van Riper
- University of Minnesota Informatics Institute, University of Minnesota, Minneapolis, MN, USA
| | - Katarzyna Kulej
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Todd M Markowski
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - David Shang
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jack Hedberg
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Luke Erber
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Benjamin Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yue Chen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
| | - Eric J Brown
- Department of Cancer Biology and the Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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4
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Jing S, Gao J, Tiwari N, Du Y, Zhu L, Gim B, Qian Y, Yue X, Lee I. SUMOylated Golgin45 associates with PML-NB to transcriptionally regulate lipid metabolism genes during heat shock stress. Commun Biol 2024; 7:532. [PMID: 38710927 PMCID: PMC11074300 DOI: 10.1038/s42003-024-06232-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 04/23/2024] [Indexed: 05/08/2024] Open
Abstract
Golgin tethers are known to mediate vesicular transport in the secretory pathway, whereas it is relatively unknown whether they may mediate cellular stress response within the cell. Here, we describe a cellular stress response during heat shock stress via SUMOylation of a Golgin tether, Golgin45. We found that Golgin45 is a SUMOylated Golgin via SUMO1 under steady state condition. Upon heat shock stress, the Golgin enters the nucleus by interacting with Importin-β2 and gets further modified by SUMO3. Importantly, SUMOylated Golgin45 appears to interact with PML and SUMO-deficient Golgin45 mutant functions as a dominant negative for PML-NB formation during heat shock stress, suppressing transcription of lipid metabolism genes. These results indicate that Golgin45 may play a role in heat stress response by transcriptional regulation of lipid metabolism genes in SUMOylation-dependent fashion.
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Affiliation(s)
- Shuaiyang Jing
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jingkai Gao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Neeraj Tiwari
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Yulei Du
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lianhui Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Bopil Gim
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yi Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Xihua Yue
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Intaek Lee
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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5
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Simon MN, Dubrana K, Palancade B. On the edge: how nuclear pore complexes rule genome stability. Curr Opin Genet Dev 2024; 84:102150. [PMID: 38215626 DOI: 10.1016/j.gde.2023.102150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/10/2023] [Accepted: 12/18/2023] [Indexed: 01/14/2024]
Abstract
Nuclear organization has emerged as a critical layer in the coordination of DNA repair activities. Distinct types of DNA lesions have notably been shown to relocate at the vicinity of nuclear pore complexes (NPCs), where specific repair pathways are favored, ultimately safeguarding genome integrity. Here, we review the most recent progress in this field, notably highlighting the increasingly diverse types of DNA structures undergoing repositioning, and the signaling pathways involved. We further discuss our growing knowledge of the molecular mechanisms underlying the choice of repair pathways at NPCs, and their conservation - or divergences. Intriguingly, a series of recent findings suggest that DNA metabolism may be coupled to NPC biogenesis and specialization, challenging our initial vision of these processes.
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Affiliation(s)
- Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe Labélisée Ligue, Aix Marseille University, Marseille, France. https://twitter.com/@IJMonod
| | - Karine Dubrana
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, F-92260 Fontenay-aux-Roses, France; Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, F-92260 Fontenay-aux-Roses, France. https://twitter.com/@DubranaLab
| | - Benoit Palancade
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France.
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6
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [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: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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7
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Gasser SM, Stutz F. SUMO in the regulation of DNA repair and transcription at nuclear pores. FEBS Lett 2023; 597:2833-2850. [PMID: 37805446 DOI: 10.1002/1873-3468.14751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/06/2023] [Accepted: 09/25/2023] [Indexed: 10/09/2023]
Abstract
Two related post-translational modifications, the covalent linkage of Ubiquitin and the Small Ubiquitin-related MOdifier (SUMO) to lysine residues, play key roles in the regulation of both DNA repair pathway choice and transcription. Whereas ubiquitination is generally associated with proteasome-mediated protein degradation, the impact of sumoylation has been more mysterious. In the cell nucleus, sumoylation effects are largely mediated by the relocalization of the modified targets, particularly in response to DNA damage. This is governed in part by the concentration of SUMO protease at nuclear pores [Melchior, F et al. (2003) Trends Biochem Sci 28, 612-618; Ptak, C and Wozniak, RW (2017) Adv Exp Med Biol 963, 111-126]. We review here the roles of sumoylation in determining genomic locus positioning relative to the nuclear envelope and to nuclear pores, to facilitate repair and regulate transcription.
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Affiliation(s)
- Susan M Gasser
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
- ISREC Foundation, Agora Cancer Research Center, Lausanne, Switzerland
| | - Françoise Stutz
- Department of Molecular and Cellular Biology, University of Geneva, Switzerland
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8
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Penzo A, Dubarry M, Brocas C, Zheng M, Mangione RM, Rougemaille M, Goncalves C, Lautier O, Libri D, Simon MN, Géli V, Dubrana K, Palancade B. A R-loop sensing pathway mediates the relocation of transcribed genes to nuclear pore complexes. Nat Commun 2023; 14:5606. [PMID: 37730746 PMCID: PMC10511428 DOI: 10.1038/s41467-023-41345-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/31/2023] [Indexed: 09/22/2023] Open
Abstract
Nuclear pore complexes (NPCs) have increasingly recognized interactions with the genome, as exemplified in yeast, where they bind transcribed or damaged chromatin. By combining genome-wide approaches with live imaging of model loci, we uncover a correlation between NPC association and the accumulation of R-loops, which are genotoxic structures formed through hybridization of nascent RNAs with their DNA templates. Manipulating hybrid formation demonstrates that R-loop accumulation per se, rather than transcription or R-loop-dependent damages, is the primary trigger for relocation to NPCs. Mechanistically, R-loop-dependent repositioning involves their recognition by the ssDNA-binding protein RPA, and SUMO-dependent interactions with NPC-associated factors. Preventing R-loop-dependent relocation leads to lethality in hybrid-accumulating conditions, while NPC tethering of a model hybrid-prone locus attenuates R-loop-dependent genetic instability. Remarkably, this relocation pathway involves molecular factors similar to those required for the association of stalled replication forks with NPCs, supporting the existence of convergent mechanisms for sensing transcriptional and genotoxic stresses.
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Affiliation(s)
- Arianna Penzo
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Marion Dubarry
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue, 13273, Marseille, France
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation et Pathogénie, F-69622, Villeurbanne, France
| | - Clémentine Brocas
- Université Paris Cité, Université Paris-Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Myriam Zheng
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Raphaël M Mangione
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Mathieu Rougemaille
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Coralie Goncalves
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Ophélie Lautier
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Domenico Libri
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue, 13273, Marseille, France
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue, 13273, Marseille, France
| | - Karine Dubrana
- Université Paris Cité, Université Paris-Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Benoit Palancade
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France.
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9
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Chakraborty S, Schirmeisen K, Lambert SA. The multifaceted functions of homologous recombination in dealing with replication-associated DNA damages. DNA Repair (Amst) 2023; 129:103548. [PMID: 37541027 DOI: 10.1016/j.dnarep.2023.103548] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/06/2023]
Abstract
The perturbation of DNA replication, a phenomena termed "replication stress", is a driving force of genome instability and a hallmark of cancer cells. Among the DNA repair mechanisms that contribute to tolerating replication stress, the homologous recombination pathway is central to the alteration of replication fork progression. In many organisms, defects in the homologous recombination machinery result in increased cell sensitivity to replication-blocking agents and a higher risk of cancer in humans. Moreover, the status of homologous recombination in cancer cells often correlates with the efficacy of anti-cancer treatment. In this review, we discuss our current understanding of the different functions of homologous recombination in fixing replication-associated DNA damage and contributing to complete genome duplication. We also examine which functions are pivotal in preventing cancer and genome instability.
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Affiliation(s)
- Shrena Chakraborty
- Institut Curie, Université PSL, CNRS UMR3348, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3348, 91400 Orsay, France; Equipe Labelisée Ligue Nationale Contre le Cancer, France
| | - Kamila Schirmeisen
- Institut Curie, Université PSL, CNRS UMR3348, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3348, 91400 Orsay, France; Equipe Labelisée Ligue Nationale Contre le Cancer, France
| | - Sarah Ae Lambert
- Institut Curie, Université PSL, CNRS UMR3348, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3348, 91400 Orsay, France; Equipe Labelisée Ligue Nationale Contre le Cancer, France.
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10
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Aguilera P, Dubarry M, Géli V, Simon MN. NPCs and APBs: two HUBs of non-canonical homology-based recombination at telomeres? Cell Cycle 2023; 22:1163-1168. [PMID: 37128641 PMCID: PMC10193864 DOI: 10.1080/15384101.2023.2206350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/05/2022] [Accepted: 10/10/2022] [Indexed: 05/03/2023] Open
Abstract
Apart from a few rare exceptions, the maintenance of functional telomeres by recombination-based mechanisms is restricted to accidental and/or pathological situations. Originally described in the yeast S. cerevisiae, this mode of telomere repair has gained interest with the discovery of telomerase negative cancers that use alternative lengthening of telomeres (ALT cancer) dependent on homologous recombination. In both yeast and humans, it has been shown that recombination at telomeres is spatially regulated and occurs preferentially at the nuclear pore complexes (NPCs) in yeast and at ALT-associated promyelocytic leukemia nuclear bodies (APBs) in human cells. Here, we discuss the potential relationships between these two membrane-less structures and their role in enabling unconventional recombination pathways.
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Affiliation(s)
- Paula Aguilera
- Centro Andaluz de Biologia Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Cientificas (CSIC), Universidad de Sevilla, Universidad Pablo de Olavide, Seville, Spain
| | - Marion Dubarry
- MAP Laboratory, INSA Lyon, Claude Bernard University UMR5240, Villeurbanne, France
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisee Ligue, Aix Marseille University, Marseille, France
| | - Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisee Ligue, Aix Marseille University, Marseille, France
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11
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Pennarun G, Picotto J, Bertrand P. Close Ties between the Nuclear Envelope and Mammalian Telomeres: Give Me Shelter. Genes (Basel) 2023; 14:genes14040775. [PMID: 37107534 PMCID: PMC10137478 DOI: 10.3390/genes14040775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 04/29/2023] Open
Abstract
The nuclear envelope (NE) in eukaryotic cells is essential to provide a protective compartment for the genome. Beside its role in connecting the nucleus with the cytoplasm, the NE has numerous important functions including chromatin organization, DNA replication and repair. NE alterations have been linked to different human diseases, such as laminopathies, and are a hallmark of cancer cells. Telomeres, the ends of eukaryotic chromosomes, are crucial for preserving genome stability. Their maintenance involves specific telomeric proteins, repair proteins and several additional factors, including NE proteins. Links between telomere maintenance and the NE have been well established in yeast, in which telomere tethering to the NE is critical for their preservation and beyond. For a long time, in mammalian cells, except during meiosis, telomeres were thought to be randomly localized throughout the nucleus, but recent advances have uncovered close ties between mammalian telomeres and the NE that play important roles for maintaining genome integrity. In this review, we will summarize these connections, with a special focus on telomere dynamics and the nuclear lamina, one of the main NE components, and discuss the evolutionary conservation of these mechanisms.
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Affiliation(s)
- Gaëlle Pennarun
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
| | - Julien Picotto
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
| | - Pascale Bertrand
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
- Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, LREV/iRCM/IBFJ, F-92260 Fontenay-aux-Roses, France
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12
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Mojumdar A, Mair N, Adam N, Cobb JA. Changes in DNA double-strand break repair during aging correlate with an increase in genomic mutations. J Mol Biol 2022; 434:167798. [PMID: 35998703 DOI: 10.1016/j.jmb.2022.167798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/24/2022]
Abstract
A double -strand break (DSB) is one of the most deleterious forms of DNA damage. In eukaryotic cells, two main repair pathways have evolved to repair DSBs, homologous recombination (HR) and non-homologous end-joining (NHEJ). HR is the predominant pathway of repair in the unicellular eukaryotic organism, S. cerevisiae. However, during replicative aging the relative use of HR and NHEJ shifts in favor of end-joining repair. By monitoring repair events in the HO-DSB system, we find that early in replicative aging there is a decrease in the association of long-range resection factors, Dna2-Sgs1 and Exo1 at the break site and a decrease in DNA resection. Subsequently, as aging progressed, the recovery of Ku70 at DSBs decreased and the break site associated with the nuclear pore complex at the nuclear periphery, which is the location where DSB repair occurs through alternative pathways that are more mutagenic. End-bridging remained intact as HR and NHEJ declined, but eventually it too became disrupted in cells at advanced replicative age. In all, our work provides insight into the molecular changes in DSB repair pathway during replicative aging. HR first declined, resulting in a transient increase in the NHEJ. However, with increased cellular divisions, Ku70 recovery at DSBs and NHEJ subsequently declined. In wild type cells of advanced replicative age, there was a high frequency of repair products with genomic deletions and microhomologies at the break junction, events not observed in young cells which repaired primarily by HR.
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Affiliation(s)
- Aditya Mojumdar
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Nicola Mair
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Nancy Adam
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jennifer A Cobb
- Departments of Biochemistry & Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada.
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13
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Vertegaal ACO. Signalling mechanisms and cellular functions of SUMO. Nat Rev Mol Cell Biol 2022; 23:715-731. [PMID: 35750927 DOI: 10.1038/s41580-022-00500-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2022] [Indexed: 12/22/2022]
Abstract
Sumoylation is an essential post-translational modification that is catalysed by a small number of modifying enzymes but regulates thousands of target proteins in a dynamic manner. Small ubiquitin-like modifiers (SUMOs) can be attached to target proteins as one or more monomers or in the form of polymers of different types. Non-covalent readers recognize SUMO-modified proteins via SUMO interaction motifs. SUMO simultaneously modifies groups of functionally related proteins to regulate predominantly nuclear processes, including gene expression, the DNA damage response, RNA processing, cell cycle progression and proteostasis. Recent progress has increased our understanding of the cellular and pathophysiological roles of SUMO modifications, extending their functions to the regulation of immunity, pluripotency and nuclear body assembly in response to oxidative stress, which partly occurs through the recently characterized mechanism of liquid-liquid phase separation. Such progress in understanding the roles and regulation of sumoylation opens new avenues for the targeting of SUMO to treat disease, and indeed the first drug blocking sumoylation is currently under investigation in clinical trials as a possible anticancer agent.
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Affiliation(s)
- Alfred C O Vertegaal
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.
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14
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Pérez-Martínez L, Wagner T, Luke B. Telomere Interacting Proteins and TERRA Regulation. Front Genet 2022; 13:872636. [PMID: 35464834 PMCID: PMC9024143 DOI: 10.3389/fgene.2022.872636] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/17/2022] [Indexed: 01/10/2023] Open
Abstract
Telomere shortening rates inversely correlate with life expectancy and hence it is critical to understand how telomere shortening is regulated. Recently, the telomeric non-coding RNA, TERRA has been implicated in the regulation of replicative senescence. To better understand how TERRA is regulated we employed a proteomics approach to look for potential RNA regulators that associate with telomeric sequences. Based on the results, we have identified proteins that may regulate TERRA in both a positive and negative manner, depending on the state of the telomere. In this mini-review, we discuss and speculate about these data to expand our understanding of TERRA and telomere interactors with respect to telomere shortening dynamics.
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Affiliation(s)
- Lara Pérez-Martínez
- Institute of Molecular Biology (IMB), Mainz, Germany
- IMDEA Food Institute, Madrid, Spain
| | - Tina Wagner
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Developmental Biology and Neurobiology (IDN), Johannes Gutenberg Universität, Mainz, Germany
| | - Brian Luke
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Developmental Biology and Neurobiology (IDN), Johannes Gutenberg Universität, Mainz, Germany
- *Correspondence: Brian Luke,
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15
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Aguilera P, Dubarry M, Hardy J, Lisby M, Simon MN, Géli V. Telomeric C-circles localize at nuclear pore complexes in Saccharomyces cerevisiae. EMBO J 2022; 41:e108736. [PMID: 35147992 PMCID: PMC8922269 DOI: 10.15252/embj.2021108736] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 11/09/2022] Open
Abstract
As in human cells, yeast telomeres can be maintained in cells lacking telomerase activity by recombination-based mechanisms known as ALT (Alternative Lengthening of Telomeres). A hallmark of ALT human cancer cells are extrachromosomal telomeric DNA elements called C-circles, whose origin and function have remained unclear. Here, we show that extrachromosomal telomeric C-circles in yeast can be detected shortly after senescence crisis and concomitantly with the production of survivors arising from "type II" recombination events. We uncover that C-circles bind to the nuclear pore complex (NPC) and to the SAGA-TREX2 complex, similar to other non-centromeric episomal DNA. Disrupting the integrity of the SAGA/TREX2 complex affects both C-circle binding to NPCs and type II telomere recombination, suggesting that NPC tethering of C-circles facilitates formation and/or propagation of the long telomere repeats characteristic of type II survivors. Furthermore, we find that disruption of the nuclear diffusion barrier impairs type II recombination. These results support a model in which concentration of C-circles at NPCs benefits type II telomere recombination, highlighting the importance of spatial coordination in ALT-type mechanisms of telomere maintenance.
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Affiliation(s)
- Paula Aguilera
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Marion Dubarry
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Julien Hardy
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Institut Paoli-Calmettes, Equipe labellisée Ligue, Aix Marseille University, Marseille, France
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16
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Wootton J, Soutoglou E. Chromatin and Nuclear Dynamics in the Maintenance of Replication Fork Integrity. Front Genet 2022; 12:773426. [PMID: 34970302 PMCID: PMC8712883 DOI: 10.3389/fgene.2021.773426] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Replication of the eukaryotic genome is a highly regulated process and stringent control is required to maintain genome integrity. In this review, we will discuss the many aspects of the chromatin and nuclear environment that play key roles in the regulation of both unperturbed and stressed replication. Firstly, the higher order organisation of the genome into A and B compartments, topologically associated domains (TADs) and sub-nuclear compartments has major implications in the control of replication timing. In addition, the local chromatin environment defined by non-canonical histone variants, histone post-translational modifications (PTMs) and enrichment of factors such as heterochromatin protein 1 (HP1) plays multiple roles in normal S phase progression and during the repair of replicative damage. Lastly, we will cover how the spatial organisation of stalled replication forks facilitates the resolution of replication stress.
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Affiliation(s)
- Jack Wootton
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Evi Soutoglou
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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17
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Epum EA, Haber JE. DNA replication: the recombination connection. Trends Cell Biol 2022; 32:45-57. [PMID: 34384659 PMCID: PMC8688190 DOI: 10.1016/j.tcb.2021.07.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 01/03/2023]
Abstract
Failure to complete DNA replication is one of the major sources of genome instability leading to aneuploidy, chromosome breakage, and chromosome rearrangements that are associated with human cancer. One of the surprising revelations of the past decade is that the completion of replication at so-called common fragile sites (CFS) occurs very late in the cell cycle - at mitosis - through a process termed MiDAS (mitotic DNA synthesis). MiDAS is strongly related to another cancer-promoting phenomenon: the activation of alternative lengthening of telomeres (ALT). Our understanding of the mechanisms of ALT and MiDAS in mammalian cells has drawn heavily from recent advances in the study of break-induced replication (BIR), especially in budding yeast. We provide new insights into the BIR, MiDAS, and ALT pathways and their shared similarities.
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18
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SUMO-Based Regulation of Nuclear Positioning to Spatially Regulate Homologous Recombination Activities at Replication Stress Sites. Genes (Basel) 2021; 12:genes12122010. [PMID: 34946958 PMCID: PMC8701742 DOI: 10.3390/genes12122010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
DNA lesions have properties that allow them to escape their nuclear compartment to achieve DNA repair in another one. Recent studies uncovered that the replication fork, when its progression is impaired, exhibits increased mobility when changing nuclear positioning and anchors to nuclear pore complexes, where specific types of homologous recombination pathways take place. In yeast models, increasing evidence points out that nuclear positioning is regulated by small ubiquitin-like modifier (SUMO) metabolism, which is pivotal to maintaining genome integrity at sites of replication stress. Here, we review how SUMO-based pathways are instrumental to spatially segregate the subsequent steps of homologous recombination during replication fork restart. In particular, we discussed how routing towards nuclear pore complex anchorage allows distinct homologous recombination pathways to take place at halted replication forks.
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19
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Merigliano C, Chiolo I. Multi-scale dynamics of heterochromatin repair. Curr Opin Genet Dev 2021; 71:206-215. [PMID: 34717276 DOI: 10.1016/j.gde.2021.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/16/2021] [Accepted: 09/27/2021] [Indexed: 10/24/2022]
Abstract
Studies across different organisms show that nuclear architecture and dynamics play central roles in different aspects of homologous recombination (HR) repair. Here we review the most recent discoveries in this field, ranging from directed motions mediating relocalization pathways, to global chromatin mobilization, local DNA looping, and changes in repair focus properties associated with clustering and phase separation. We discuss how these dynamics work in different contexts, including molecular mechanisms and regulatory pathways involved. We specifically highlight how they function in pericentromeric heterochromatin, which presents a unique environment for HR repair given the abundance of repeated DNA sequences prone to aberrant recombination, the 'silent' chromatin state, and the phase separation characterizing this domain.
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Affiliation(s)
- Chiara Merigliano
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA.
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20
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Nucleolar release of rDNA repeats for repair involves SUMO-mediated untethering by the Cdc48/p97 segregase. Nat Commun 2021; 12:4918. [PMID: 34389719 PMCID: PMC8363623 DOI: 10.1038/s41467-021-25205-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Ribosomal RNA genes (rDNA) are highly unstable and susceptible to rearrangement due to their repetitive nature and active transcriptional status. Sequestration of rDNA in the nucleolus suppresses uncontrolled recombination. However, broken repeats must be first released to the nucleoplasm to allow repair by homologous recombination. Nucleolar release of broken rDNA repeats is conserved from yeast to humans, but the underlying molecular mechanisms are currently unknown. Here we show that DNA damage induces phosphorylation of the CLIP-cohibin complex, releasing membrane-tethered rDNA from the nucleolus in Saccharomyces cerevisiae. Downstream of phosphorylation, SUMOylation of CLIP-cohibin is recognized by Ufd1 via its SUMO-interacting motif, which targets the complex for disassembly through the Cdc48/p97 chaperone. Consistent with a conserved mechanism, UFD1L depletion in human cells impairs rDNA release. The dynamic and regulated assembly and disassembly of the rDNA-tethering complex is therefore a key determinant of nucleolar rDNA release and genome integrity.
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21
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Lamm N, Rogers S, Cesare AJ. Chromatin mobility and relocation in DNA repair. Trends Cell Biol 2021; 31:843-855. [PMID: 34183232 DOI: 10.1016/j.tcb.2021.06.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 01/17/2023]
Abstract
The nucleus is a dynamic environment containing chromatin, membraneless organelles, and specialized molecular structures at the nuclear membrane. Within the spectrum of DNA repair activities are observations of increased mobility of damaged chromatin and the displacement of DNA lesions to specific nuclear environments. Here, we focus on the role that nuclear-specific filamentous actin plays in mobilizing damaged chromatin in response to DNA double-strand breaks and replication stress. We also examine nuclear pore complexes and promyelocytic leukemia-nuclear bodies as specialized platforms for homology-directed repair. The literature suggests an emerging model where specific types of DNA lesions are subjected to nuclear-derived forces that mobilize damaged chromatin and promote interaction with repair hubs to facilitate specialized repair reactions.
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Affiliation(s)
- Noa Lamm
- Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, 2145, Australia
| | - Samuel Rogers
- Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, 2145, Australia
| | - Anthony J Cesare
- Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, 2145, Australia.
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22
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Impacts of chromatin dynamics and compartmentalization on DNA repair. DNA Repair (Amst) 2021; 105:103162. [PMID: 34182258 DOI: 10.1016/j.dnarep.2021.103162] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/10/2021] [Accepted: 06/17/2021] [Indexed: 11/22/2022]
Abstract
The proper spatial organization of DNA, RNA, and proteins is critical for a variety of cellular processes. The genome is organized into numerous functional units, such as topologically associating domains (TADs), the formation of which is regulated by both proteins and RNA. In addition, a group of chromatin-bound proteins with the ability to undergo liquid-liquid phase separation (LLPS) can affect the spatial organization and compartmentalization of chromatin, RNA, and proteins by forming condensates, conferring unique properties to specific chromosomal regions. Although the regulation of DNA repair by histone modifications and chromatin accessibility is well established, the impacts of higher-order chromatin and protein organization on the DNA damage response (DDR) have not been appreciated until recently. In this review, we will focus on the movement of chromatin during the DDR, the compartmentalization of DDR proteins via LLPS, and the roles of membraneless nuclear bodies and transcription in DNA repair. With this backdrop, we will discuss the importance of the spatial organization of chromatin and proteins for the maintenance of genome integrity.
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23
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Chang YC, Oram MK, Bielinsky AK. SUMO-Targeted Ubiquitin Ligases and Their Functions in Maintaining Genome Stability. Int J Mol Sci 2021; 22:ijms22105391. [PMID: 34065507 PMCID: PMC8161396 DOI: 10.3390/ijms22105391] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 02/06/2023] Open
Abstract
Small ubiquitin-like modifier (SUMO)-targeted E3 ubiquitin ligases (STUbLs) are specialized enzymes that recognize SUMOylated proteins and attach ubiquitin to them. They therefore connect the cellular SUMOylation and ubiquitination circuits. STUbLs participate in diverse molecular processes that span cell cycle regulated events, including DNA repair, replication, mitosis, and transcription. They operate during unperturbed conditions and in response to challenges, such as genotoxic stress. These E3 ubiquitin ligases modify their target substrates by catalyzing ubiquitin chains that form different linkages, resulting in proteolytic or non-proteolytic outcomes. Often, STUbLs function in compartmentalized environments, such as the nuclear envelope or kinetochore, and actively aid in nuclear relocalization of damaged DNA and stalled replication forks to promote DNA repair or fork restart. Furthermore, STUbLs reside in the same vicinity as SUMO proteases and deubiquitinases (DUBs), providing spatiotemporal control of their targets. In this review, we focus on the molecular mechanisms by which STUbLs help to maintain genome stability across different species.
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24
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Whalen JM, Dhingra N, Wei L, Zhao X, Freudenreich CH. Relocation of Collapsed Forks to the Nuclear Pore Complex Depends on Sumoylation of DNA Repair Proteins and Permits Rad51 Association. Cell Rep 2021; 31:107635. [PMID: 32402281 DOI: 10.1016/j.celrep.2020.107635] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/07/2020] [Accepted: 04/21/2020] [Indexed: 10/24/2022] Open
Abstract
Expanded CAG repeats form stem-loop secondary structures that lead to fork stalling and collapse. Previous work has shown that these collapsed forks relocalize to nuclear pore complexes (NPCs) in late S phase in a manner dependent on replication, the nucleoporin Nup84, and the Slx5 protein, which prevents repeat fragility and instability. Here, we show that binding of the Smc5/6 complex to the collapsed fork triggers Mms21-dependent sumoylation of fork-associated DNA repair proteins, and that RPA, Rad52, and Rad59 are the key sumoylation targets that mediate relocation. The SUMO interacting motifs of Slx5 target collapsed forks to the NPC. Notably, Rad51 foci only co-localize with the repeat after it is anchored to the nuclear periphery and Rad51 exclusion from the early collapsed fork is dependent on RPA sumoylation. This pathway may provide a mechanism to constrain recombination at stalled or collapsed forks until it is required for fork restart.
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Affiliation(s)
- Jenna M Whalen
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Nalini Dhingra
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Lei Wei
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Medford, MA 02155, USA; Program in Genetics, Tufts University, Boston, MA 02111, USA.
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25
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Qiu GH, Zheng X, Fu M, Huang C, Yang X. The decreased exclusion of nuclear eccDNA: From molecular and subcellular levels to human aging and age-related diseases. Ageing Res Rev 2021; 67:101306. [PMID: 33610814 DOI: 10.1016/j.arr.2021.101306] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
Extrachromosomal circular DNA (eccDNA) accumulates within the nucleus of eukaryotic cells during physiological aging and in age-related diseases (ARDs) and the accumulation could be caused by the declined exclusion of nuclear eccDNA in these states. This review focuses on the formation of eccDNA and the roles of some main factors, such as nuclear pore complexes (NPCs), nucleoplasmic reticulum (NR), and nuclear actin, in eccDNA exclusion. eccDNAs are mostly formed from non-coding DNA during DNA damage repair. They move to NPCs along nuclear actin and are excluded out of the nucleus through functional NPCs in young and healthy cells. However, it has been demonstrated that defective NPCs, abnormal NPC components and nuclear actin rods are increased in aged cells, various cancers and certain other ARDs such as cardiovascular diseases, premature aging, neurodegenerative diseases and myopathies. Therefore, mainly resulting from the increase of dysfunctional NPCs, the exclusion of nuclear eccDNAs may be reduced and eccDNAs thus accumulate within the nucleus in aging and the aforementioned ARDs. In addition, the protective function of non-coding DNA in tumorigenesis is further discussed.
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Affiliation(s)
- Guo-Hua Qiu
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China.
| | - Xintian Zheng
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Mingjun Fu
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Cuiqin Huang
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Xiaoyan Yang
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
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26
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Matmati S, Lambert S, Géli V, Coulon S. Telomerase Repairs Collapsed Replication Forks at Telomeres. Cell Rep 2021; 30:3312-3322.e3. [PMID: 32160539 DOI: 10.1016/j.celrep.2020.02.065] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/17/2020] [Accepted: 02/14/2020] [Indexed: 02/06/2023] Open
Abstract
Telomeres are difficult-to-replicate sites whereby replication itself may threaten telomere integrity. We investigate, in fission yeast, telomere replication dynamics in telomerase-negative cells to unmask problems associated with telomere replication. Two-dimensional gel analysis reveals that replication of telomeres is severely impaired and correlates with an accumulation of replication intermediates that arises from stalled and collapsed forks. In the absence of telomerase, Rad51, Mre11-Rad50-Nbs1 (MRN) complex, and its co-factor CtIPCtp1 become critical to maintain telomeres, indicating that homologous recombination processes these intermediates to facilitate fork restart. We further show that a catalytically dead mutant of telomerase prevents Ku recruitment to telomeres, suggesting that telomerase and Ku both compete for the binding of telomeric-free DNA ends that are likely to originate from a reversed fork. We infer that Ku removal at collapsed telomeric forks allows telomerase to repair broken telomeres, thereby shielding telomeres from homologous recombination.
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Affiliation(s)
- Samah Matmati
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France
| | - Sarah Lambert
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France; University Paris Sud, Paris-Saclay University, CNRS, UMR3348, F-91405 Orsay, France
| | - Vincent Géli
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France.
| | - Stéphane Coulon
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France.
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27
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Nuclear Periphery and Telomere Maintenance: TERRA Joins the Stage. Trends Genet 2021; 37:608-611. [PMID: 33663806 DOI: 10.1016/j.tig.2021.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 11/21/2022]
Abstract
Long noncoding (lnc)RNAs derived from telomeres, the ends of linear eukaryotic chromosomes, help to maintain telomere length and stability by multiple means, including regulation of telomerase activity and recombination-based telomere maintenance. New findings in yeast promote a model in which telomere attachment to the nuclear envelope regulates telomere transcription and maintenance.
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28
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Charifi F, Churikov D, Eckert-Boulet N, Minguet C, Jourquin F, Hardy J, Lisby M, Simon MN, Géli V. Rad52 SUMOylation functions as a molecular switch that determines a balance between the Rad51- and Rad59-dependent survivors. iScience 2021; 24:102231. [PMID: 33748714 PMCID: PMC7966982 DOI: 10.1016/j.isci.2021.102231] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/01/2021] [Accepted: 02/22/2021] [Indexed: 12/21/2022] Open
Abstract
Functional telomeres in yeast lacking telomerase can be restored by rare Rad51- or Rad59-dependent recombination events that lead to type I and type II survivors, respectively. We previously proposed that polySUMOylation of proteins and the SUMO-targeted ubiquitin ligase Slx5-Slx8 are key factors in type II recombination. Here, we show that SUMOylation of Rad52 favors the formation of type I survivors. Conversely, preventing Rad52 SUMOylation partially bypasses the requirement of Slx5-Slx8 for type II recombination. We further report that SUMO-dependent proteasomal degradation favors type II recombination. Finally, inactivation of Rad59, but not Rad51, impairs the relocation of eroded telomeres to the Nuclear Pore complexes (NPCs). We propose that Rad59 cooperates with non-SUMOylated Rad52 to promote type II recombination at NPCs, resulting in the emergence of more robust survivors akin to ALT cancer cells. Finally, neither Rad59 nor Rad51 is required by itself for the survival of established type II survivors.
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Affiliation(s)
- Ferose Charifi
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Dmitri Churikov
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | | | - Christopher Minguet
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Frédéric Jourquin
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Julien Hardy
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Marie-Noëlle Simon
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Marseille, 13009, France
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29
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The nuclear pore primes recombination-dependent DNA synthesis at arrested forks by promoting SUMO removal. Nat Commun 2020; 11:5643. [PMID: 33159083 PMCID: PMC7648084 DOI: 10.1038/s41467-020-19516-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 10/16/2020] [Indexed: 12/31/2022] Open
Abstract
Nuclear Pore complexes (NPCs) act as docking sites to anchor particular DNA lesions facilitating DNA repair by elusive mechanisms. Using replication fork barriers in fission yeast, we report that relocation of arrested forks to NPCs occurred after Rad51 loading and its enzymatic activity. The E3 SUMO ligase Pli1 acts at arrested forks to safeguard integrity of nascent strands and generates poly-SUMOylation which promote relocation to NPCs but impede the resumption of DNA synthesis by homologous recombination (HR). Anchorage to NPCs allows SUMO removal by the SENP SUMO protease Ulp1 and the proteasome, promoting timely resumption of DNA synthesis. Preventing Pli1-mediated SUMO chains was sufficient to bypass the need for anchorage to NPCs and the inhibitory effect of poly-SUMOylation on HR-mediated DNA synthesis. Our work establishes a novel spatial control of Recombination-Dependent Replication (RDR) at a unique sequence that is distinct from mechanisms engaged at collapsed-forks and breaks within repeated sequences. In yeast, collapsed forks shift to the nuclear periphery to associate with two distinct perinuclear anchorage sites such as the nuclear pore complex. Here, the authors reveal the mechanisms engaged at nuclear pore complex facilitating fork integrity and restart via SUMO regulation.
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30
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Replication stress conferred by POT1 dysfunction promotes telomere relocalization to the nuclear pore. Genes Dev 2020; 34:1619-1636. [PMID: 33122293 PMCID: PMC7706707 DOI: 10.1101/gad.337287.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 09/21/2020] [Indexed: 12/31/2022]
Abstract
In this study, Pinzaru et al. set out to uncover the pathways that enable the proliferation of cells expressing cancer-associated POT1 mutations. Using complementary genetic and proteomic approaches, the authors identify a conserved function for the NPC in resolving replication defects at telomere loci. Mutations in the telomere-binding protein POT1 are associated with solid tumors and leukemias. POT1 alterations cause rapid telomere elongation, ATR kinase activation, telomere fragility, and accelerated tumor development. Here, we define the impact of mutant POT1 alleles through complementary genetic and proteomic approaches based on CRISPR interference and biotin-based proximity labeling, respectively. These screens reveal that replication stress is a major vulnerability in cells expressing mutant POT1, which manifests as increased telomere mitotic DNA synthesis at telomeres. Our study also unveils a role for the nuclear pore complex in resolving replication defects at telomeres. Depletion of nuclear pore complex subunits in the context of POT1 dysfunction increases DNA damage signaling, telomere fragility and sister chromatid exchanges. Furthermore, we observed telomere repositioning to the nuclear periphery driven by nuclear F-actin polymerization in cells with POT1 mutations. In conclusion, our study establishes that relocalization of dysfunctional telomeres to the nuclear periphery is critical to preserve telomere repeat integrity.
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31
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Miné-Hattab J, Chiolo I. Complex Chromatin Motions for DNA Repair. Front Genet 2020; 11:800. [PMID: 33061931 PMCID: PMC7481375 DOI: 10.3389/fgene.2020.00800] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/06/2020] [Indexed: 12/26/2022] Open
Abstract
A number of studies across different model systems revealed that chromatin undergoes significant changes in dynamics in response to DNA damage. These include local motion changes at damage sites, increased nuclear exploration of both damaged and undamaged loci, and directed motions to new nuclear locations associated with certain repair pathways. These studies also revealed the need for new analytical methods to identify directed motions in a context of mixed trajectories, and the importance of investigating nuclear dynamics over different time scales to identify diffusion regimes. Here we provide an overview of the current understanding of this field, including imaging and analytical methods developed to investigate nuclear dynamics in different contexts. These dynamics are essential for genome integrity. Identifying the molecular mechanisms responsible for these movements is key to understanding how their misregulation contributes to cancer and other genome instability disorders.
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Affiliation(s)
- Judith Miné-Hattab
- UMR 3664, CNRS, Institut Curie, PSL Research University, Paris, France
- UMR 3664, CNRS, Institut Curie, Sorbonne Université, Paris, France
| | - Irene Chiolo
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, United States
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32
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Whalen JM, Freudenreich CH. Location, Location, Location: The Role of Nuclear Positioning in the Repair of Collapsed Forks and Protection of Genome Stability. Genes (Basel) 2020; 11:E635. [PMID: 32526925 PMCID: PMC7348918 DOI: 10.3390/genes11060635] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 05/29/2020] [Accepted: 06/04/2020] [Indexed: 12/14/2022] Open
Abstract
Components of the nuclear pore complex (NPC) have been shown to play a crucial role in protecting against replication stress, and recovery from some types of stalled or collapsed replication forks requires movement of the DNA to the NPC in order to maintain genome stability. The role that nuclear positioning has on DNA repair has been investigated in several systems that inhibit normal replication. These include structure forming sequences (expanded CAG repeats), protein mediated stalls (replication fork barriers (RFBs)), stalls within the telomere sequence, and the use of drugs known to stall or collapse replication forks (HU + MMS or aphidicolin). Recently, the mechanism of relocation for collapsed replication forks to the NPC has been elucidated. Here, we will review the types of replication stress that relocate to the NPC, the current models for the mechanism of relocation, and the currently known protective effects of this movement.
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Affiliation(s)
- Jenna M. Whalen
- Department of Biology, Tufts University, Medford, MA 02155, USA;
| | - Catherine H. Freudenreich
- Department of Biology, Tufts University, Medford, MA 02155, USA;
- Program in Genetics, Tufts University, Boston, MA 02111, USA
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33
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Maestroni L, Reyes C, Vaurs M, Gachet Y, Tournier S, Géli V, Coulon S. Nuclear envelope attachment of telomeres limits TERRA and telomeric rearrangements in quiescent fission yeast cells. Nucleic Acids Res 2020; 48:3029-3041. [PMID: 31980821 PMCID: PMC7102995 DOI: 10.1093/nar/gkaa043] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 11/12/2022] Open
Abstract
Telomere anchoring to nuclear envelope (NE) is a key feature of nuclear genome architecture. Peripheral localization of telomeres is important for chromatin silencing, telomere replication and for the control of inappropriate recombination. Here, we report that fission yeast quiescent cells harbor predominantly a single telomeric cluster anchored to the NE. Telomere cluster association to the NE relies on Rap1-Bqt4 interaction, which is impacted by the length of telomeric sequences. In quiescent cells, reducing telomere length or deleting bqt4, both result in an increase in transcription of the telomeric repeat-containing RNA (TERRA). In the absence of Bqt4, telomere shortening leads to deep increase in TERRA level and the concomitant formation of subtelomeric rearrangements (STEEx) that accumulate massively in quiescent cells. Taken together, our data demonstrate that Rap1-Bqt4-dependent telomere association to NE preserves telomere integrity in post-mitotic cells, preventing telomeric transcription and recombination. This defines the nuclear periphery as an area where recombination is restricted, creating a safe zone for telomeres of post-mitotic cells.
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Affiliation(s)
- Laetitia Maestroni
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Marseille, France. Equipe labellisée Ligue contre le Cancer, France
| | - Céline Reyes
- LBCMCP, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Mélina Vaurs
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Marseille, France. Equipe labellisée Ligue contre le Cancer, France
| | - Yannick Gachet
- LBCMCP, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Sylvie Tournier
- LBCMCP, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex, France
| | - Vincent Géli
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Marseille, France. Equipe labellisée Ligue contre le Cancer, France
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Marseille, France. Equipe labellisée Ligue contre le Cancer, France
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34
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Loe TK, Li JSZ, Zhang Y, Azeroglu B, Boddy MN, Denchi EL. Telomere length heterogeneity in ALT cells is maintained by PML-dependent localization of the BTR complex to telomeres. Genes Dev 2020; 34:650-662. [PMID: 32217664 PMCID: PMC7197349 DOI: 10.1101/gad.333963.119] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/26/2020] [Indexed: 12/11/2022]
Abstract
In this study, Loe et al. sought to understand ALT-associated PML bodies (APBs) and their function in the alternative lengthening of telomeres (ALT) pathway, a telomerase-independent mechanism of telomere extension that some cancer cells that use. Using CRISPR/Cas9 to delete PML and APB components from ALT-positive cells, they found that PML is required for the ALT mechanism, and that this necessity stems from APBs’ role in localizing the BLM–TOP3A–RMI (BTR) complex to ALT telomere ends, suggesting that BTR localization to telomeres is sufficient to sustain ALT activity. Telomeres consist of TTAGGG repeats bound by protein complexes that serve to protect the natural end of linear chromosomes. Most cells maintain telomere repeat lengths by using the enzyme telomerase, although there are some cancer cells that use a telomerase-independent mechanism of telomere extension, termed alternative lengthening of telomeres (ALT). Cells that use ALT are characterized, in part, by the presence of specialized PML nuclear bodies called ALT-associated PML bodies (APBs). APBs localize to and cluster telomeric ends together with telomeric and DNA damage factors, which led to the proposal that these bodies act as a platform on which ALT can occur. However, the necessity of APBs and their function in the ALT pathway has remained unclear. Here, we used CRISPR/Cas9 to delete PML and APB components from ALT-positive cells to cleanly define the function of APBs in ALT. We found that PML is required for the ALT mechanism, and that this necessity stems from APBs’ role in localizing the BLM–TOP3A–RMI (BTR) complex to ALT telomere ends. Strikingly, recruitment of the BTR complex to telomeres in a PML-independent manner bypasses the need for PML in the ALT pathway, suggesting that BTR localization to telomeres is sufficient to sustain ALT activity.
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Affiliation(s)
- Taylor K Loe
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Julia Su Zhou Li
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
| | - Yuxiang Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Benura Azeroglu
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Michael Nicholas Boddy
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Eros Lazzerini Denchi
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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35
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Saik NO, Park N, Ptak C, Adames N, Aitchison JD, Wozniak RW. Recruitment of an Activated Gene to the Yeast Nuclear Pore Complex Requires Sumoylation. Front Genet 2020; 11:174. [PMID: 32211027 PMCID: PMC7067905 DOI: 10.3389/fgene.2020.00174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/13/2020] [Indexed: 01/10/2023] Open
Abstract
In addition to their role in regulating transport across the nuclear envelope, increasing evidence suggests nuclear pore complexes (NPCs) function in regulating gene expression. For example, the induction of certain genes (e.g., yeast INO1) is accompanied by their movement from the nuclear interior to NPCs. As sumoylation has been linked to the regulation of chromatin spatial organization and transcriptional activity, we investigated the role of sumoylation in the expression and NPC recruitment of the INO1 gene. We observed that induction of INO1 is accompanied by both increased and decreased sumoylation of proteins associated with specific regions along the INO1 locus. Furthermore, we show that the E3 ligase Siz2/Nfi1 is required for targeting the INO1 locus to the NPC where it interacts with the SUMO isopeptidase Ulp1. Our data suggest that this interaction is required for both the association of INO1 with the NPC and for its normal expression. These results imply that sumoylation is a key regulator of INO1 targeting to the NPC, and a cycle of sumoylation and NPC-associated desumoylation events contribute to the regulation of INO1 expression.
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Affiliation(s)
- Natasha O Saik
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Nogi Park
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada.,Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Neil Adames
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada.,New Culture, San Francisco, CA, United States
| | - John D Aitchison
- Seattle Children's Research Institute, Seattle, WA, United States
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
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36
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The nuclear pore complex prevents sister chromatid recombination during replicative senescence. Nat Commun 2020; 11:160. [PMID: 31919430 PMCID: PMC6952416 DOI: 10.1038/s41467-019-13979-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022] Open
Abstract
The Nuclear Pore Complex (NPC) has emerged as an important hub for processing various types of DNA damage. Here, we uncover that fusing a DNA binding domain to the NPC basket protein Nup1 reduces telomere relocalization to nuclear pores early after telomerase inactivation. This Nup1 modification also impairs the relocalization to the NPC of expanded CAG/CTG triplet repeats. Strikingly, telomerase negative cells bypass senescence when expressing this Nup1 modification by maintaining a minimal telomere length compatible with proliferation through rampant unequal exchanges between sister chromatids. We further report that a Nup1 mutant lacking 36 C-terminal residues recapitulates the phenotypes of the Nup1-LexA fusion indicating a direct role of Nup1 in the relocation of stalled forks to NPCs and restriction of error-prone recombination between repeated sequences. Our results reveal a new mode of telomere maintenance that could shed light on how 20% of cancer cells are maintained without telomerase or ALT. The Nuclear Pore Complex has been linked to DNA damage processing. Here the authors reveal that the Nup1 C-terminus is critical for the relocalization of eroded telomeres to nuclear pores and that modification of Nup1 promotes sister chromatid recombination and unleashes a new telomere maintenance mechanism.
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37
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Asymmetric Processing of DNA Ends at a Double-Strand Break Leads to Unconstrained Dynamics and Ectopic Translocation. Cell Rep 2019; 24:2614-2628.e4. [PMID: 30184497 DOI: 10.1016/j.celrep.2018.07.102] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/07/2018] [Accepted: 07/27/2018] [Indexed: 01/10/2023] Open
Abstract
Multiple pathways regulate the repair of double-strand breaks (DSBs) to suppress potentially dangerous ectopic recombination. Both sequence and chromatin context are thought to influence pathway choice between non-homologous end-joining (NHEJ) and homology-driven recombination. To test the effect of repetitive sequences on break processing, we have inserted TG-rich repeats on one side of an inducible DSB at the budding yeast MAT locus on chromosome III. Five clustered Rap1 sites within a break-proximal TG repeat are sufficient to block Mre11-Rad50-Xrs2 recruitment, impair resection, and favor elongation by telomerase. The two sides of the break lose end-to-end tethering and show enhanced, uncoordinated movement. Only the TG-free side is resected and shifts to the nuclear periphery. In contrast to persistent DSBs without TG repeats that are repaired by imprecise NHEJ, nearly all survivors of repeat-proximal DSBs repair the break by a homology-driven, non-reciprocal translocation from ChrIII-R to ChrVII-L. This suppression of imprecise NHEJ at TG-repeat-flanked DSBs requires the Uls1 translocase activity.
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38
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Nguéa P A, Robertson J, Herrera MC, Chymkowitch P, Enserink JM. Desumoylation of RNA polymerase III lies at the core of the Sumo stress response in yeast. J Biol Chem 2019; 294:18784-18795. [PMID: 31676685 DOI: 10.1074/jbc.ra119.009721] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
Post-translational modification by small ubiquitin-like modifier (Sumo) regulates many cellular processes, including the adaptive response to various types of stress, referred to as the Sumo stress response (SSR). However, it remains unclear whether the SSR involves a common set of core proteins regardless of the type of stress or whether each particular type of stress induces a stress-specific SSR that targets a unique, largely nonoverlapping set of Sumo substrates. In this study, we used MS and a Gene Ontology approach to identify differentially sumoylated proteins during heat stress, hyperosmotic stress, oxidative stress, nitrogen starvation, and DNA alkylation in Saccharomyces cerevisiae cells. Our results indicate that each stress triggers a specific SSR signature centered on proteins involved in transcription, translation, and chromatin regulation. Strikingly, whereas the various stress-specific SSRs were largely nonoverlapping, all types of stress tested here resulted in desumoylation of subunits of RNA polymerase III, which correlated with a decrease in tRNA synthesis. We conclude that desumoylation and subsequent inhibition of RNA polymerase III constitutes the core of all stress-specific SSRs in yeast.
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Affiliation(s)
- Aurélie Nguéa P
- Department of Molecular Cell Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0371 Oslo, Norway; Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0371 Oslo, Norway
| | - Joseph Robertson
- Department of Molecular Cell Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0371 Oslo, Norway
| | - Maria Carmen Herrera
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0371 Oslo, Norway; Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0371 Oslo, Norway
| | - Pierre Chymkowitch
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, 0372 Oslo, Norway.
| | - Jorrit M Enserink
- Department of Molecular Cell Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0371 Oslo, Norway; Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0371 Oslo, Norway.
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39
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Caridi CP, Plessner M, Grosse R, Chiolo I. Nuclear actin filaments in DNA repair dynamics. Nat Cell Biol 2019; 21:1068-1077. [PMID: 31481797 PMCID: PMC6736642 DOI: 10.1038/s41556-019-0379-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
Recent development of innovative tools for live imaging of actin filaments (F-actin) enabled the detection of surprising nuclear structures responding to various stimuli, challenging previous models that actin is substantially monomeric in the nucleus. We review these discoveries, focusing on double-strand break (DSB) repair responses. These studies revealed a remarkable network of nuclear filaments and regulatory mechanisms coordinating chromatin dynamics with repair progression and led to a paradigm shift by uncovering the directed movement of repair sites.
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Affiliation(s)
| | - Matthias Plessner
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Irene Chiolo
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, USA.
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40
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Abstract
DNA double-strand breaks (DSBs) are particularly challenging to repair in pericentromeric heterochromatin because of the increased risk of aberrant recombination in highly repetitive sequences. Recent studies have identified specialized mechanisms enabling 'safe' homologous recombination (HR) repair in heterochromatin. These include striking nuclear actin filaments (F-actin) and myosins that drive the directed motion of repair sites to the nuclear periphery for 'safe' repair. Here, we summarize our current understanding of the mechanisms involved, and propose how they might operate in the context of a phase-separated environment.
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41
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Min J, Wright WE, Shay JW. Clustered telomeres in phase-separated nuclear condensates engage mitotic DNA synthesis through BLM and RAD52. Genes Dev 2019; 33:814-827. [PMID: 31171703 PMCID: PMC6601508 DOI: 10.1101/gad.324905.119] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/24/2019] [Indexed: 11/25/2022]
Abstract
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. One of the hallmarks of ALT cancer is the excessively clustered telomeres in promyelocytic leukemia (PML) bodies, represented as large bright telomere foci. Here, we present a model system that generates telomere clustering in nuclear polySUMO (small ubiquitin-like modification)/polySIM (SUMO-interacting motif) condensates, analogous to PML bodies, and thus artificially engineered ALT-associated PML body (APB)-like condensates in vivo. We observed that the ALT-like phenotypes (i.e., a small fraction of heterogeneous telomere lengths and formation of C circles) are rapidly induced by introducing the APB-like condensates together with BLM through its helicase domain, accompanied by ssDNA generation and RPA accumulation at telomeres. Moreover, these events lead to mitotic DNA synthesis (MiDAS) at telomeres mediated by RAD52 through its highly conserved N-terminal domain. We propose that the clustering of large amounts of telomeres in human cancers promotes ALT that is mediated by MiDAS, analogous to Saccharomyces cerevisiae type II ALT survivors.
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Affiliation(s)
- Jaewon Min
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
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42
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Höpfler M, Kern MJ, Straub T, Prytuliak R, Habermann BH, Pfander B, Jentsch S. Slx5/Slx8-dependent ubiquitin hotspots on chromatin contribute to stress tolerance. EMBO J 2019; 38:embj.2018100368. [PMID: 31015336 PMCID: PMC6545562 DOI: 10.15252/embj.2018100368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/29/2019] [Accepted: 04/03/2019] [Indexed: 12/27/2022] Open
Abstract
Chromatin is a highly regulated environment, and protein association with chromatin is often controlled by post‐translational modifications and the corresponding enzymatic machinery. Specifically, SUMO‐targeted ubiquitin ligases (STUbLs) have emerged as key players in nuclear quality control, genome maintenance, and transcription. However, how STUbLs select specific substrates among myriads of SUMOylated proteins on chromatin remains unclear. Here, we reveal a remarkable co‐localization of the budding yeast STUbL Slx5/Slx8 and ubiquitin at seven genomic loci that we term “ubiquitin hotspots”. Ubiquitylation at these sites depends on Slx5/Slx8 and protein turnover on the Cdc48 segregase. We identify the transcription factor‐like Ymr111c/Euc1 to associate with these sites and to be a critical determinant of ubiquitylation. Euc1 specifically targets Slx5/Slx8 to ubiquitin hotspots via bipartite binding of Slx5 that involves the Slx5 SUMO‐interacting motifs and an additional, novel substrate recognition domain. Interestingly, the Euc1‐ubiquitin hotspot pathway acts redundantly with chromatin modifiers of the H2A.Z and Rpd3L pathways in specific stress responses. Thus, our data suggest that STUbL‐dependent ubiquitin hotspots shape chromatin during stress adaptation.
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Affiliation(s)
- Markus Höpfler
- Max Planck Institute of Biochemistry, Molecular Cell Biology, Martinsried, Germany
| | - Maximilian J Kern
- Max Planck Institute of Biochemistry, Molecular Cell Biology, Martinsried, Germany
| | - Tobias Straub
- Biomedizinisches Centrum, Core Facility Bioinformatics, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Roman Prytuliak
- Max Planck Institute of Biochemistry, Computational Biology Group, Martinsried, Germany
| | - Bianca H Habermann
- Max Planck Institute of Biochemistry, Computational Biology Group, Martinsried, Germany.,Aix-Marseille Univ, CNRS, IBDM UMR 7288, Marseille Cedex 9, France
| | - Boris Pfander
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
| | - Stefan Jentsch
- Max Planck Institute of Biochemistry, Molecular Cell Biology, Martinsried, Germany
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43
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Ribosomal RNA gene repeats associate with the nuclear pore complex for maintenance after DNA damage. PLoS Genet 2019; 15:e1008103. [PMID: 30998688 PMCID: PMC6490929 DOI: 10.1371/journal.pgen.1008103] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/30/2019] [Accepted: 03/20/2019] [Indexed: 12/04/2022] Open
Abstract
The ribosomal RNA genes (rDNA) comprise a highly repetitive gene cluster. The copy number of genes at this locus can readily change and is therefore one of the most unstable regions of the genome. DNA damage in rDNA occurs after binding of the replication fork blocking protein Fob1 in S phase, which triggers unequal sister chromatid recombination. However, the precise mechanisms by which such DNA double-strand breaks (DSBs) are repaired is not well understood. Here, we demonstrate that the conserved protein kinase Tel1 maintains rDNA stability after replication fork arrest. We show that rDNA associates with nuclear pores, which is dependent on DNA damage checkpoint kinases Mec1/Tel1 and replisome component Tof1. These findings suggest that rDNA-nuclear pore association is due to a replication fork block and subsequent DSB. Indeed, quantitative microscopy revealed that rDNA is relocated to the nuclear periphery upon induction of a DSB. Finally, rDNA stability was reduced in strains where this association with the nuclear envelope was prevented, which suggests its importance for avoiding improper recombination repair that could induce repeat instability. Ribosomal RNA genes (rDNA) comprise an unstable region of the genome due to their highly repetitive structure and elevated levels of transcription. Collision between transcription and replication machineries of rDNA, which may lead to DNA damage in the form of a double-stranded break, is avoided by the replication fork barrier. When such a break is repaired by homologous recombination with a repeat on the sister chromatid, the abundance of homologous sequences may lead to a change in copy number. In most organisms, however, only small variations in copy number are observed, indicating that the rDNA is stably maintained. Our results suggest that some parts of rDNA become localized to the nuclear pore complex in a DNA double-strand break-dependent manner. This localization requires the protein kinase Tel1, which is involved in the DNA damage response pathway, and factors that recruit condensin, which facilitates condensation and segregation of rDNA during mitosis. We found that the rDNA becomes unstable when association with the nuclear envelope was prevented. Thus, the localization represents a unique strategy for maintaining repeat integrity after DNA damage.
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44
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Zhao X. SUMO-Mediated Regulation of Nuclear Functions and Signaling Processes. Mol Cell 2019; 71:409-418. [PMID: 30075142 DOI: 10.1016/j.molcel.2018.07.027] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/06/2018] [Accepted: 07/23/2018] [Indexed: 12/23/2022]
Abstract
Since the discovery of SUMO twenty years ago, SUMO conjugation has become a widely recognized post-translational modification that targets a myriad of proteins in many processes. Great progress has been made in understanding the SUMO pathway enzymes, substrate sumoylation, and the interplay between sumoylation and other regulatory mechanisms in a variety of contexts. As these research directions continue to generate insights into SUMO-based regulation, several mechanisms by which sumoylation and desumoylation can orchestrate large biological effects are emerging. These include the ability to target multiple proteins within the same cellular structure or process, respond dynamically to external and internal stimuli, and modulate signaling pathways involving other post-translational modifications. Focusing on nuclear function and intracellular signaling, this review highlights a broad spectrum of historical data and recent advances with the aim of providing an overview of mechanisms underlying SUMO-mediated global effects to stimulate further inquiry into intriguing roles of SUMO.
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Affiliation(s)
- Xiaolan Zhao
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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45
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Rodriguez-Berriguete G, Granata G, Puliyadi R, Tiwana G, Prevo R, Wilson RS, Yu S, Buffa F, Humphrey TC, McKenna WG, Higgins GS. Nucleoporin 54 contributes to homologous recombination repair and post-replicative DNA integrity. Nucleic Acids Res 2018; 46:7731-7746. [PMID: 29986057 PMCID: PMC6125679 DOI: 10.1093/nar/gky569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 05/25/2018] [Accepted: 06/14/2018] [Indexed: 12/21/2022] Open
Abstract
The nuclear pore complex (NPC) machinery is emerging as an important determinant in the maintenance of genome integrity and sensitivity to DNA double-strand break (DSB)-inducing agents, such as ionising radiation (IR). In this study, using a high-throughput siRNA screen, we identified the central channel NPC protein Nup54, and concomitantly its molecular partners Nup62 and Nup58, as novel factors implicated in radiosensitivity. Nup54 depletion caused an increase in cell death by mitotic catastrophe after IR, and specifically enhanced both the duration of the G2 arrest and the radiosensitivity of cells that contained replicated DNA at the time of IR exposure. Nup54-depleted cells also exhibited increased formation of chromosome aberrations arisen from replicated DNA. Interestingly, we found that Nup54 is epistatic with the homologous recombination (HR) factor Rad51. Moreover, using specific DNA damage repair reporters, we observed a decreased HR repair activity upon Nup54 knockdown. In agreement with a role in HR repair, we also demonstrated a decreased formation of HR-linked DNA synthesis foci and sister chromatid exchanges after IR in cells depleted of Nup54. Our study reveals a novel role for Nup54 in the response to IR and the maintenance of HR-mediated genome integrity.
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Affiliation(s)
- Gonzalo Rodriguez-Berriguete
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Giovanna Granata
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Rathi Puliyadi
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Gaganpreet Tiwana
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Remko Prevo
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Rhodri S Wilson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Sheng Yu
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Francesca Buffa
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Timothy C Humphrey
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - W Gillies McKenna
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Geoff S Higgins
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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46
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Caridi CP, D'Agostino C, Ryu T, Zapotoczny G, Delabaere L, Li X, Khodaverdian VY, Amaral N, Lin E, Rau AR, Chiolo I. Nuclear F-actin and myosins drive relocalization of heterochromatic breaks. Nature 2018; 559:54-60. [PMID: 29925946 PMCID: PMC6051730 DOI: 10.1038/s41586-018-0242-8] [Citation(s) in RCA: 232] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 05/18/2018] [Indexed: 12/13/2022]
Abstract
Heterochromatin mainly comprises repeated DNA sequences that are prone to ectopic recombination. In Drosophila cells, 'safe' repair of heterochromatic double-strand breaks by homologous recombination relies on the relocalization of repair sites to the nuclear periphery before strand invasion. The mechanisms responsible for this movement were unknown. Here we show that relocalization occurs by directed motion along nuclear actin filaments assembled at repair sites by the Arp2/3 complex. Relocalization requires nuclear myosins associated with the heterochromatin repair complex Smc5/6 and the myosin activator Unc45, which is recruited to repair sites by Smc5/6. ARP2/3, actin nucleation and myosins also relocalize heterochromatic double-strand breaks in mouse cells. Defects in this pathway result in impaired heterochromatin repair and chromosome rearrangements. These findings identify de novo nuclear actin filaments and myosins as effectors of chromatin dynamics for heterochromatin repair and stability in multicellular eukaryotes.
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Affiliation(s)
- Christopher P Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Carla D'Agostino
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Taehyun Ryu
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Xiao Li
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Varandt Y Khodaverdian
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Nuno Amaral
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
- Karolinska Institute, Stockholm, Sweden
| | - Emily Lin
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Alesandra R Rau
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA.
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47
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Caridi PC, Delabaere L, Zapotoczny G, Chiolo I. And yet, it moves: nuclear and chromatin dynamics of a heterochromatic double-strand break. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0291. [PMID: 28847828 PMCID: PMC5577469 DOI: 10.1098/rstb.2016.0291] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2017] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is mostly composed of repeated DNA sequences prone to aberrant recombination. How cells maintain the stability of these sequences during double-strand break (DSB) repair has been a long-standing mystery. Studies in Drosophila cells revealed that faithful homologous recombination repair of heterochromatic DSBs relies on the striking relocalization of repair sites to the nuclear periphery before Rad51 recruitment and repair progression. Here, we summarize our current understanding of this response, including the molecular mechanisms involved, and conserved pathways in mammalian cells. We will highlight important similarities with pathways identified in budding yeast for repair of other types of repeated sequences, including rDNA and short telomeres. We will also discuss the emerging role of chromatin composition and regulation in heterochromatin repair progression. Together, these discoveries challenged previous assumptions that repair sites are substantially static in multicellular eukaryotes, that heterochromatin is largely inert in the presence of DSBs, and that silencing and compaction in this domain are obstacles to repair. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.
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Affiliation(s)
- P Christopher Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
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48
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Poli J, Gasser SM, Papamichos-Chronakis M. The INO80 remodeller in transcription, replication and repair. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0290. [PMID: 28847827 DOI: 10.1098/rstb.2016.0290] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2017] [Indexed: 02/06/2023] Open
Abstract
The accessibility of eukaryotic genomes to the action of enzymes involved in transcription, replication and repair is maintained despite the organization of DNA into nucleosomes. This access is often regulated by the action of ATP-dependent nucleosome remodellers. The INO80 class of nucleosome remodellers has unique structural features and it is implicated in a diverse array of functions, including transcriptional regulation, DNA replication and DNA repair. Underlying these diverse functions is the catalytic activity of the main ATPase subunit, which in the context of a multisubunit complex can shift nucleosomes and carry out histone dimer exchange. In vitro studies showed that INO80 promotes replication fork progression on a chromatin template, while in vivo it was shown to facilitate replication fork restart after stalling and to help evict RNA polymerase II at transcribed genes following the collision of a replication fork with transcription. More recent work in yeast implicates INO80 in the general eviction and degradation of nucleosomes following high doses of oxidative DNA damage. Beyond these replication and repair functions, INO80 was shown to repress inappropriate transcription at promoters in the opposite direction to the coding sequence. Here we discuss the ways in which INO80's diverse functions help maintain genome integrity.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Jérôme Poli
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.,University of Montpellier and Centre de Recherche en Biologie Cellulaire (CRBM), UMR5237, CNRS, Montpellier 34095, Cedex 5, France
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland .,Faculty of Natural Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Manolis Papamichos-Chronakis
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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49
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Caridi CP, Delabaere L, Tjong H, Hopp H, Das D, Alber F, Chiolo I. Quantitative Methods to Investigate the 4D Dynamics of Heterochromatic Repair Sites in Drosophila Cells. Methods Enzymol 2018. [PMID: 29523239 DOI: 10.1016/bs.mie.2017.11.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Heterochromatin is mostly composed of long stretches of repeated DNA sequences prone to ectopic recombination during double-strand break (DSB) repair. In Drosophila, "safe" homologous recombination (HR) repair of heterochromatic DSBs relies on a striking relocalization of repair sites to the nuclear periphery. Central to understanding heterochromatin repair is the ability to investigate the 4D dynamics (movement in space and time) of repair sites. A specific challenge of these studies is preventing phototoxicity and photobleaching effects while imaging the sample over long periods of time, and with sufficient time points and Z-stacks to track repair foci over time. Here we describe an optimized approach for high-resolution live imaging of heterochromatic DSBs in Drosophila cells, with a specific emphasis on the fluorescent markers and imaging setup used to capture the motion of repair foci over long-time periods. We detail approaches that minimize photobleaching and phototoxicity with a DeltaVision widefield deconvolution microscope, and image processing techniques for signal recovery postimaging using SoftWorX and Imaris software. We present a method to derive mean square displacement curves revealing some of the biophysical properties of the motion. Finally, we describe a method in R to identify tracts of directed motions (DMs) in mixed trajectories. These approaches enable a deeper understanding of the mechanisms of heterochromatin dynamics and genome stability in the three-dimensional context of the nucleus and have broad applicability in the field of nuclear dynamics.
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Affiliation(s)
| | | | - Harianto Tjong
- University of Southern California, Los Angeles, CA, United States
| | - Hannah Hopp
- University of Southern California, Los Angeles, CA, United States
| | - Devika Das
- University of Southern California, Los Angeles, CA, United States
| | - Frank Alber
- University of Southern California, Los Angeles, CA, United States
| | - Irene Chiolo
- University of Southern California, Los Angeles, CA, United States.
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50
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Abstract
Chromatin is organized into higher-order structures that form subcompartments in interphase nuclei. Different categories of specialized enzymes act on chromatin and regulate its compaction and biophysical characteristics in response to physiological conditions. We present an overview of the function of chromatin structure and its dynamic changes in response to genotoxic stress, focusing on both subnuclear organization and the physical mobility of DNA. We review the requirements and mechanisms that cause chromatin relocation, enhanced mobility, and chromatin unfolding as a consequence of genotoxic lesions. An intriguing link has been established recently between enhanced chromatin dynamics and histone loss.
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Affiliation(s)
- Michael H Hauer
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
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