1
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Vines AJ, Cox K, Leland BA, King MC. Homology-directed repair involves multiple strand invasion cycles in fission yeast. Mol Biol Cell 2022; 33:ar30. [PMID: 35080989 PMCID: PMC9250353 DOI: 10.1091/mbc.e20-07-0433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Homology-directed repair of DNA double-strand breaks (DSBs) represents a highly faithful pathway. Non–crossover repair dominates in mitotically growing cells, likely through a preference for synthesis-dependent strand annealing (SDSA). How homology-directed repair mechanism choice is orchestrated in time and space is not well understood. Here, we develop a microscopy-based assay in living fission yeast to determine the dynamics and kinetics of an engineered, site-specific interhomologue repair event. We observe highly efficient homology search and homology-directed repair in this system. Surprisingly, the initial distance between the DSB and the donor sequence does not correlate with the duration of repair. Instead, we observe that repair often involves multiple site-specific and Rad51-dependent colocalization events between the DSB and donor sequence. Upon loss of the RecQ helicase Rqh1 (BLM in humans) we observe rapid repair possibly involving a single strand invasion event, suggesting that multiple strand invasion cycles antagonized by Rqh1 could reflect ongoing SDSA. However, failure to colocalize with the donor sequence and execute repair is also more likely in rqh1Δ cells, possibly reflecting erroneous strand invasion. This work has implications for the molecular etiology of Bloom syndrome, caused by mutations in BLM and characterized by aberrant sister chromatid crossovers and inefficient repair.
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Affiliation(s)
- Amanda J Vines
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut, USA, 06520
| | - Kenneth Cox
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut, USA, 06520
| | - Bryan A Leland
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut, USA, 06520
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut, USA, 06520
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2
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Xu X, Wang M, Sun J, Yu Z, Li G, Yang N, Xu RM. Structure specific DNA recognition by the SLX1-SLX4 endonuclease complex. Nucleic Acids Res 2021; 49:7740-7752. [PMID: 34181713 PMCID: PMC8287910 DOI: 10.1093/nar/gkab542] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 06/04/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
The SLX1–SLX4 structure-specific endonuclease complex is involved in processing diverse DNA damage intermediates, including resolution of Holliday junctions, collapse of stalled replication forks and removal of DNA flaps. The nuclease subunit SLX1 is inactive on its own, but become activated upon binding to SLX4 via its conserved C-terminal domain (CCD). Yet, how the SLX1–SLX4 complex recognizes specific DNA structure and chooses cleavage sites remains unknown. Here we show, through a combination of structural, biochemical and computational analyses, that the SAP domain of SLX4 is critical for efficient and accurate processing of 5′-flap DNA. It binds the minor groove of DNA about one turn away from the flap junction, and the 5′-flap is implicated in binding the core domain of SLX1. This binding mode accounts for specific recognition of 5′-flap DNA and specification of cleavage site by the SLX1–SLX4 complex.
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Affiliation(s)
- Xiang Xu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Mingzhu Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China
| | - Jixue Sun
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China
| | - Zhenyu Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,School of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Na Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China
| | - Rui-Ming Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,School of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Falquet B, Rass U. Structure-Specific Endonucleases and the Resolution of Chromosome Underreplication. Genes (Basel) 2019; 10:E232. [PMID: 30893921 PMCID: PMC6470701 DOI: 10.3390/genes10030232] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 12/11/2022] Open
Abstract
Complete genome duplication in every cell cycle is fundamental for genome stability and cell survival. However, chromosome replication is frequently challenged by obstacles that impede DNA replication fork (RF) progression, which subsequently causes replication stress (RS). Cells have evolved pathways of RF protection and restart that mitigate the consequences of RS and promote the completion of DNA synthesis prior to mitotic chromosome segregation. If there is entry into mitosis with underreplicated chromosomes, this results in sister-chromatid entanglements, chromosome breakage and rearrangements and aneuploidy in daughter cells. Here, we focus on the resolution of persistent replication intermediates by the structure-specific endonucleases (SSEs) MUS81, SLX1-SLX4 and GEN1. Their actions and a recently discovered pathway of mitotic DNA repair synthesis have emerged as important facilitators of replication completion and sister chromatid detachment in mitosis. As RS is induced by oncogene activation and is a common feature of cancer cells, any advances in our understanding of the molecular mechanisms related to chromosome underreplication have important biomedical implications.
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Affiliation(s)
- Benoît Falquet
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
- Faculty of Natural Sciences, University of Basel, Petersplatz 10, CH-4003 Basel, Switzerland.
| | - Ulrich Rass
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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4
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Warmerdam DO, Wolthuis RMF. Keeping ribosomal DNA intact: a repeating challenge. Chromosome Res 2018; 27:57-72. [PMID: 30556094 PMCID: PMC6394564 DOI: 10.1007/s10577-018-9594-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/20/2018] [Accepted: 11/29/2018] [Indexed: 02/06/2023]
Abstract
More than half of the human genome consists of repetitive sequences, with the ribosomal DNA (rDNA) representing two of the largest repeats. Repetitive rDNA sequences may form a threat to genomic integrity and cellular homeostasis due to the challenging aspects of their transcription, replication, and repair. Predisposition to cancer, premature aging, and neurological impairment in ataxia-telangiectasia and Bloom syndrome, for instance, coincide with increased cellular rDNA repeat instability. However, the mechanisms by which rDNA instability contributes to these hereditary syndromes and tumorigenesis remain unknown. Here, we review how cells govern rDNA stability and how rDNA break repair influences expansion and contraction of repeat length, a process likely associated with human disease. Recent advancements in CRISPR-based genome engineering may help to explain how cells keep their rDNA intact in the near future.
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Affiliation(s)
- Daniël O Warmerdam
- CRISPR Platform, University of Amsterdam, Cancer Center Amsterdam, Amsterdam UMC, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands.
| | - Rob M F Wolthuis
- Section of Oncogenetics, Department of Clinical Genetics, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam UMC, de Boelelaan 1117, 1081 HV, Amsterdam, the Netherlands
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5
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Abstract
The SLX4/FANCP tumor suppressor has emerged as a key player in the maintenance of genome stability, making pivotal contributions to the repair of interstrand cross-links, homologous recombination, and in response to replication stress genome-wide as well as at specific loci such as common fragile sites and telomeres. SLX4 does so in part by acting as a scaffold that controls and coordinates the XPF-ERCC1, MUS81-EME1, and SLX1 structure-specific endonucleases in different DNA repair and recombination mechanisms. It also interacts with other important DNA repair and cell cycle control factors including MSH2, PLK1, TRF2, and TOPBP1 as well as with ubiquitin and SUMO. This review aims at providing an up-to-date and comprehensive view on the key functions that SLX4 fulfills to maintain genome stability as well as to highlight and discuss areas of uncertainty and emerging concepts.
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Affiliation(s)
- Jean-Hugues Guervilly
- a CRCM, CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes , Marseille , France
| | - Pierre Henri Gaillard
- a CRCM, CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes , Marseille , France
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6
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Matmati S, Vaurs M, Escandell JM, Maestroni L, Nakamura TM, Ferreira MG, Géli V, Coulon S. The fission yeast Stn1-Ten1 complex limits telomerase activity via its SUMO-interacting motif and promotes telomeres replication. SCIENCE ADVANCES 2018; 4:eaar2740. [PMID: 29774234 PMCID: PMC5955624 DOI: 10.1126/sciadv.aar2740] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/29/2018] [Indexed: 06/01/2023]
Abstract
Mammalian CST (CTC1-STN1-TEN1) complex fulfills numerous functions including rescue of the stalled replication forks and termination of telomerase action. In fission yeast lacking the CTC1 ortholog, the Stn1-Ten1 complex restricts telomerase action via its sumoylation-mediated interaction with Tpz1TPP1. We identify a small ubiquitin-like modifier (SUMO)-interacting motif (SIM) in the carboxyl-terminal part of Stn1 and show that this domain is crucial for SUMO and Tpz1-SUMO interactions. Point mutations in the SIM (Stn1-226) lead to telomere elongation, impair Stn1-Ten1 recruitment to telomeres, and enhance telomerase binding, revealing that Stn1 SIM domain contributes to the inhibition of telomerase activity at chromosome ends. Our results suggest that Stn1-Ten1 promotes DNA synthesis at telomeres to limit single-strand DNA accumulation. We further demonstrate that Stn1 functions in the replication of telomeric and subtelomeric regions in a Taz1-independent manner. Genetic analysis reveals that misregulation of origin firing and/or telomerase inhibition circumvents the replication defects of the stn1-226 mutant. Together, our results show that the Stn1-Ten1 complex has a dual function at telomeres by limiting telomerase action and promoting chromosome end replication.
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Affiliation(s)
- Samah Matmati
- CRCM, CNRS, INSERM, Aix-Marseille Université, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 27 Boulevard Lei Roure, Marseille, France
| | - Mélina Vaurs
- CRCM, CNRS, INSERM, Aix-Marseille Université, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 27 Boulevard Lei Roure, Marseille, France
| | - José M. Escandell
- Telomere and Genome Stability Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Laetitia Maestroni
- CRCM, CNRS, INSERM, Aix-Marseille Université, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 27 Boulevard Lei Roure, Marseille, France
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Miguel G. Ferreira
- Telomere and Genome Stability Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Institute for Research on Cancer and Aging, Nice, Faculty of Medicine, CNRS UMR7284, INSERM U1081, University of Nice Sophia Antipolis, Nice, France
| | - Vincent Géli
- CRCM, CNRS, INSERM, Aix-Marseille Université, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 27 Boulevard Lei Roure, Marseille, France
| | - Stéphane Coulon
- CRCM, CNRS, INSERM, Aix-Marseille Université, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 27 Boulevard Lei Roure, Marseille, France
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7
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Noguchi C, Grothusen G, Anandarajan V, Martínez-Lage García M, Terlecky D, Corzo K, Tanaka K, Nakagawa H, Noguchi E. Genetic controls of DNA damage avoidance in response to acetaldehyde in fission yeast. Cell Cycle 2016; 16:45-58. [PMID: 27687866 DOI: 10.1080/15384101.2016.1237326] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Acetaldehyde, a primary metabolite of alcohol, forms DNA adducts and disrupts the DNA replication process, causing genomic instability, a hallmark of cancer. Indeed, chronic alcohol consumption accounts for approximately 3.6% of all cancers worldwide. However, how the adducts are prevented and repaired after acetaldehyde exposure is not well understood. In this report, we used the fission yeast Schizosaccharomyces pombe as a model organism to comprehensively understand the genetic controls of DNA damage avoidance in response to acetaldehyde. We demonstrate that Atd1 functions as a major acetaldehyde detoxification enzyme that prevents accumulation of Rad52-DNA repair foci, while Atd2 and Atd3 have minor roles in acetaldehyde detoxification. We found that acetaldehyde causes DNA damage at the replication fork and activates the cell cycle checkpoint to coordinate cell cycle arrest with DNA repair. Our investigation suggests that acetaldehyde-mediated DNA adducts include interstrand-crosslinks and DNA-protein crosslinks. We also demonstrate that acetaldehyde activates multiple DNA repair pathways. Nucleotide excision repair and homologous recombination, which are both epistatically linked to the Fanconi anemia pathway, have major roles in acetaldehyde tolerance, while base excision repair and translesion synthesis also contribute to the prevention of acetaldehyde-dependent genomic instability. We also show the involvement of Wss1-related metalloproteases, Wss1 and Wss2, in acetaldehyde tolerance. These results indicate that acetaldehyde causes cellular stresses that require cells to coordinate multiple cellular processes in order to prevent genomic instability. Considering that acetaldehyde is a human carcinogen, our genetic studies serve as a guiding investigation into the mechanisms of acetaldehyde-dependent genomic instability and carcinogenesis.
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Affiliation(s)
- Chiaki Noguchi
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Grant Grothusen
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Vinesh Anandarajan
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Marta Martínez-Lage García
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Daniel Terlecky
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Krysten Corzo
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
| | - Katsunori Tanaka
- b Department of Bioscience , School of Science and Technology, Kwansei Gakuin University , Sanda , Japan
| | - Hiroshi Nakagawa
- c Gastroenterology Division, Department of Medicine, University of Pennsylvania Perelman School of Medicine , PA , USA
| | - Eishi Noguchi
- a Department of Biochemistry and Molecular Biology , Drexel University College of Medicine , Philadelphia , PA , USA
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8
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Talhaoui I, Bernal M, Mazón G. The nucleolytic resolution of recombination intermediates in yeast mitotic cells. FEMS Yeast Res 2016; 16:fow065. [PMID: 27509904 DOI: 10.1093/femsyr/fow065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2016] [Indexed: 12/20/2022] Open
Abstract
In mitotic cells, the repair of double-strand breaks by homologous recombination (HR) is important for genome integrity. HR requires the orchestration of a subset of pathways for timely removal of joint-molecule intermediates that would otherwise prevent segregation of chromosomes in mitosis. The use of nucleases to resolve recombination intermediates is important for chromosome segregation, but is hazardous because crossovers can result in loss of heterozygosity or chromosome rearrangements. Unregulated use of the nucleases involved in the resolution of recombination intermediates could also be a risk during replication. The yeast models (Saccharomyces cerevisae and Schizosaccharomyces pombe) have proven effective in determining the major nucleases involved in the processing of such intermediates: Mus81-Mms4 and Yen1. Mus81-Mms4 and Yen1 are regulated by the cell cycle in a gradual activation during G2/M to keep the crossing-over risk low while ensuring proper removal of HJ intermediates.
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Affiliation(s)
- Ibtissam Talhaoui
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Manuel Bernal
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Gerard Mazón
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
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9
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Gadaleta MC, Das MM, Tanizawa H, Chang YT, Noma KI, Nakamura TM, Noguchi E. Swi1Timeless Prevents Repeat Instability at Fission Yeast Telomeres. PLoS Genet 2016; 12:e1005943. [PMID: 26990647 PMCID: PMC4798670 DOI: 10.1371/journal.pgen.1005943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/25/2016] [Indexed: 01/09/2023] Open
Abstract
Genomic instability associated with DNA replication stress is linked to cancer and genetic pathologies in humans. If not properly regulated, replication stress, such as fork stalling and collapse, can be induced at natural replication impediments present throughout the genome. The fork protection complex (FPC) is thought to play a critical role in stabilizing stalled replication forks at several known replication barriers including eukaryotic rDNA genes and the fission yeast mating-type locus. However, little is known about the role of the FPC at other natural impediments including telomeres. Telomeres are considered to be difficult to replicate due to the presence of repetitive GT-rich sequences and telomere-binding proteins. However, the regulatory mechanism that ensures telomere replication is not fully understood. Here, we report the role of the fission yeast Swi1Timeless, a subunit of the FPC, in telomere replication. Loss of Swi1 causes telomere shortening in a telomerase-independent manner. Our epistasis analyses suggest that heterochromatin and telomere-binding proteins are not major impediments for telomere replication in the absence of Swi1. Instead, repetitive DNA sequences impair telomere integrity in swi1Δ mutant cells, leading to the loss of repeat DNA. In the absence of Swi1, telomere shortening is accompanied with an increased recruitment of Rad52 recombinase and more frequent amplification of telomere/subtelomeres, reminiscent of tumor cells that utilize the alternative lengthening of telomeres pathway (ALT) to maintain telomeres. These results suggest that Swi1 ensures telomere replication by suppressing recombination and repeat instability at telomeres. Our studies may also be relevant in understanding the potential role of Swi1Timeless in regulation of telomere stability in cancer cells. In every round of the cell cycle, cells must accurately replicate their full genetic information. This process is highly regulated, as defects during DNA replication cause genomic instability, leading to various genetic disorders including cancers. To thwart these problems, cells carry an array of complex mechanisms to deal with various obstacles found across the genome that can hamper DNA replication and cause DNA damage. Understanding how these mechanisms are regulated and orchestrated is of paramount importance in the field. In this report, we describe how Swi1, a Timeless-related protein in fission yeast, regulates efficient replication of telomeres, which are considered to be difficult to replicate due to the presence of repetitive DNA and telomere-binding proteins. We show that Swi1 prevents telomere damage and maintains telomere length by protecting integrity of telomeric repeats. Swi1-mediated telomere maintenance is independent of telomerase activity, and loss of Swi1 causes hyper-activation of recombination-based telomere maintenance, which generates heterogeneous telomeres. Similar telomerase-independent and recombination-dependent mechanism is utilized by approximately 15% of human cancers, linking telomere replication defects with cancer development. Thus, our study may be relevant in understanding the role of telomere replication defects in the development of cancers in humans.
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Affiliation(s)
- Mariana C. Gadaleta
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Mukund M. Das
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hideki Tanizawa
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Ya-Ting Chang
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ken-ichi Noma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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10
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Mejia-Ramirez E, Limbo O, Langerak P, Russell P. Critical Function of γH2A in S-Phase. PLoS Genet 2015; 11:e1005517. [PMID: 26368543 PMCID: PMC4569340 DOI: 10.1371/journal.pgen.1005517] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/20/2015] [Indexed: 11/24/2022] Open
Abstract
Phosphorylation of histone H2AX by ATM and ATR establishes a chromatin recruitment platform for DNA damage response proteins. Phospho-H2AX (γH2AX) has been most intensively studied in the context of DNA double-strand breaks caused by exogenous clastogens, but recent studies suggest that DNA replication stress also triggers formation of γH2A (ortholog of γH2AX) in Schizosaccharomyces pombe. Here, a focused genetic screen in fission yeast reveals that γH2A is critical when there are defects in Replication Factor C (RFC), which loads proliferating cell nuclear antigen (PCNA) clamp onto duplex DNA. Surprisingly Chk1, Cds1/Chk2 and the Rad9-Hus1-Rad1 checkpoint clamp, which are crucial for surviving many genotoxins, are fully dispensable in RFC-defective cells. Immunoblot analysis confirms that Rad9-Hus1-Rad1 is not required for formation of γH2A by Rad3/ATR in S-phase. Defects in DNA polymerase epsilon, which binds PCNA in the replisome, also create an acute need for γH2A. These requirements for γH2A were traced to its role in docking with Brc1, which is a 6-BRCT-domain protein that is structurally related to budding yeast Rtt107 and mammalian PTIP. Brc1, which localizes at stalled replication forks by binding γH2A, prevents aberrant formation of Replication Protein A (RPA) foci in RFC-impaired cells, suggesting that Brc1-coated chromatin stabilizes replisomes when PCNA or DNA polymerase availability limits DNA synthesis. ATM (ataxia telangiectasia mutated) and ATR (ATM and Rad3 related) are evolutionary conserved protein kinases that phosphorylate the carboxyl-tail of histone H2AX in chromatin flanking DNA lesions. Phosphorylated histone H2AX (aka γH2AX) tethers important DNA damage response (DDR) proteins to DNA double-strand breaks but its function during DNA replication is unclear. A novel genetic screen reveals that a partial defect in Replication Factor C (RFC) creates a critical requirement for γH2AX in fission yeast. These studies indicate that γH2AX stabilizes replication forks by recruiting Brc1 when RFC is unable to load the DNA clamp known as proliferating cell nuclear antigen (PCNA) onto duplex DNA. Surprisingly, this activity of γH2AX is more critical than ATM/ATR-mediated activation of the checkpoint kinase Chk1 and Chk2.
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Affiliation(s)
- Eva Mejia-Ramirez
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Oliver Limbo
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Petra Langerak
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paul Russell
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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11
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Increased meiotic crossovers and reduced genome stability in absence of Schizosaccharomyces pombe Rad16 (XPF). Genetics 2014; 198:1457-72. [PMID: 25293972 DOI: 10.1534/genetics.114.171355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Schizosaccharomyces pombe Rad16 is the ortholog of the XPF structure-specific endonuclease, which is required for nucleotide excision repair and implicated in the single strand annealing mechanism of recombination. We show that Rad16 is important for proper completion of meiosis. In its absence, cells suffer reduced spore viability and abnormal chromosome segregation with evidence for fragmentation. Recombination between homologous chromosomes is increased, while recombination within sister chromatids is reduced, suggesting that Rad16 is not required for typical homolog crossovers but influences the balance of recombination between the homolog and the sister. In vegetative cells, rad16 mutants show evidence for genome instability. Similar phenotypes are associated with mutants affecting Rhp14(XPA) but are independent of other nucleotide excision repair proteins such as Rad13(XPG). Thus, the XPF/XPA module of the nucleotide excision repair pathway is incorporated into multiple aspects of genome maintenance even in the absence of external DNA damage.
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12
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Gritenaite D, Princz LN, Szakal B, Bantele SCS, Wendeler L, Schilbach S, Habermann BH, Matos J, Lisby M, Branzei D, Pfander B. A cell cycle-regulated Slx4-Dpb11 complex promotes the resolution of DNA repair intermediates linked to stalled replication. Genes Dev 2014; 28:1604-19. [PMID: 25030699 PMCID: PMC4102767 DOI: 10.1101/gad.240515.114] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A key function of the DNA damage response is to facilitate the bypass of replication fork-stalling DNA lesions. Template switch reactions allow such a bypass and involve the formation of DNA joint molecules (JMs) between sister chromatids. However, the regulation of JM resolution is poorly understood. Pfander and colleagues elucidate a mechanism in yeast that critically controls JM resolution by the Mus81–Mms4 endonuclease. The data show that the conserved complex comprising scaffold proteins Dbp11 and Slx4 integrates cellular inputs and regulates the activation of the JM-resolving nuclease Mus81. A key function of the cellular DNA damage response is to facilitate the bypass of replication fork-stalling DNA lesions. Template switch reactions allow such a bypass and involve the formation of DNA joint molecules (JMs) between sister chromatids. These JMs need to be resolved before cell division; however, the regulation of this process is only poorly understood. Here, we identify a regulatory mechanism in yeast that critically controls JM resolution by the Mus81–Mms4 endonuclease. Central to this regulation is a conserved complex comprising the scaffold proteins Dpb11 and Slx4 that is under stringent control. Cell cycle-dependent phosphorylation of Slx4 by Cdk1 promotes the Dpb11–Slx4 interaction, while in mitosis, phosphorylation of Mms4 by Polo-like kinase Cdc5 promotes the additional association of Mus81–Mms4 with the complex, thereby promoting JM resolution. Finally, the DNA damage checkpoint counteracts Mus81–Mms4 binding to the Dpb11–Slx4 complex. Thus, Dpb11–Slx4 integrates several cellular inputs and participates in the temporal program for activation of the JM-resolving nuclease Mus81.
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Affiliation(s)
- Dalia Gritenaite
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Lissa N Princz
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Barnabas Szakal
- Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy
| | - Susanne C S Bantele
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Lina Wendeler
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sandra Schilbach
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Bianca H Habermann
- Computational Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Joao Matos
- Institute of Biochemistry, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - Michael Lisby
- Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Dana Branzei
- Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy
| | - Boris Pfander
- DNA Replication and Genome Integrity, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
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13
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Abstract
Four-way DNA intermediates, called Holliday junctions (HJs), can form during meiotic and mitotic recombination, and their removal is crucial for chromosome segregation. A group of ubiquitous and highly specialized structure-selective endonucleases catalyze the cleavage of HJs into two disconnected DNA duplexes in a reaction called HJ resolution. These enzymes, called HJ resolvases, have been identified in bacteria and their bacteriophages, archaea, and eukaryotes. In this review, we discuss fundamental aspects of the HJ structure and their interaction with junction-resolving enzymes. This is followed by a brief discussion of the eubacterial RuvABC enzymes, which provide the paradigm for HJ resolvases in other organisms. Finally, we review the biochemical and structural properties of some well-characterized resolvases from archaea, bacteriophage, and eukaryotes.
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Affiliation(s)
- Haley D M Wyatt
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, United Kingdom
| | - Stephen C West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, United Kingdom
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14
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Antoniali G, Lirussi L, Poletto M, Tell G. Emerging roles of the nucleolus in regulating the DNA damage response: the noncanonical DNA repair enzyme APE1/Ref-1 as a paradigmatical example. Antioxid Redox Signal 2014; 20:621-39. [PMID: 23879289 PMCID: PMC3901381 DOI: 10.1089/ars.2013.5491] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 07/22/2013] [Indexed: 12/25/2022]
Abstract
SIGNIFICANCE An emerging concept in DNA repair mechanisms is the evidence that some key enzymes, besides their role in the maintenance of genome stability, display also unexpected noncanonical functions associated with RNA metabolism in specific subcellular districts (e.g., nucleoli). During the evolution of these key enzymes, the acquisition of unfolded domains significantly amplified the possibility to interact with different partners and substrates, possibly explaining their phylogenetic gain of functions. RECENT ADVANCES After nucleolar stress or DNA damage, many DNA repair proteins can freely relocalize from nucleoli to the nucleoplasm. This process may represent a surveillance mechanism to monitor the synthesis and correct assembly of ribosomal units affecting cell cycle progression or inducing p53-mediated apoptosis or senescence. CRITICAL ISSUES A paradigm for this kind of regulation is represented by some enzymes of the DNA base excision repair (BER) pathway, such as apurinic/apyrimidinic endonuclease 1 (APE1). In this review, the role of the nucleolus and the noncanonical functions of the APE1 protein are discussed in light of their possible implications in human pathologies. FUTURE DIRECTIONS A productive cross-talk between DNA repair enzymes and proteins involved in RNA metabolism seems reasonable as the nucleolus is emerging as a dynamic functional hub that coordinates cell growth arrest and DNA repair mechanisms. These findings will drive further analyses on other BER proteins and might imply that nucleic acid processing enzymes are more versatile than originally thought having evolved DNA-targeted functions after a previous life in the early RNA world.
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Affiliation(s)
- Giulia Antoniali
- Department of Medical and Biological Sciences, University of Udine , Udine, Italy
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15
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Rass U. Resolving branched DNA intermediates with structure-specific nucleases during replication in eukaryotes. Chromosoma 2013; 122:499-515. [PMID: 24008669 PMCID: PMC3827899 DOI: 10.1007/s00412-013-0431-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 08/03/2013] [Accepted: 08/08/2013] [Indexed: 11/29/2022]
Abstract
Genome duplication requires that replication forks track the entire length of every chromosome. When complications occur, homologous recombination-mediated repair supports replication fork movement and recovery. This leads to physical connections between the nascent sister chromatids in the form of Holliday junctions and other branched DNA intermediates. A key role in the removal of these recombination intermediates falls to structure-specific nucleases such as the Holliday junction resolvase RuvC in Escherichia coli. RuvC is also known to cut branched DNA intermediates that originate directly from blocked replication forks, targeting them for origin-independent replication restart. In eukaryotes, multiple structure-specific nucleases, including Mus81-Mms4/MUS81-EME1, Yen1/GEN1, and Slx1-Slx4/SLX1-SLX4 (FANCP) have been implicated in the resolution of branched DNA intermediates. It is becoming increasingly clear that, as a group, they reflect the dual function of RuvC in cleaving recombination intermediates and failing replication forks to assist the DNA replication process.
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Affiliation(s)
- Ulrich Rass
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland,
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16
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Pardo B, Aguilera A. Complex chromosomal rearrangements mediated by break-induced replication involve structure-selective endonucleases. PLoS Genet 2012; 8:e1002979. [PMID: 23071463 PMCID: PMC3459980 DOI: 10.1371/journal.pgen.1002979] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 08/08/2012] [Indexed: 11/18/2022] Open
Abstract
DNA double-strand break (DSB) repair occurring in repeated DNA sequences often leads to the generation of chromosomal rearrangements. Homologous recombination normally ensures a faithful repair of DSBs through a mechanism that transfers the genetic information of an intact donor template to the broken molecule. When only one DSB end shares homology to the donor template, conventional gene conversion fails to occur and repair can be channeled to a recombination-dependent replication pathway termed break-induced replication (BIR), which is prone to produce chromosome non-reciprocal translocations (NRTs), a classical feature of numerous human cancers. Using a newly designed substrate for the analysis of DSB-induced chromosomal translocations, we show that Mus81 and Yen1 structure-selective endonucleases (SSEs) promote BIR, thus causing NRTs. We propose that Mus81 and Yen1 are recruited at the strand invasion intermediate to allow the establishment of a replication fork, which is required to complete BIR. Replication template switching during BIR, a feature of this pathway, engenders complex chromosomal rearrangements when using repeated DNA sequences dispersed over the genome. We demonstrate here that Mus81 and Yen1, together with Slx4, also promote template switching during BIR. Altogether, our study provides evidence for a role of SSEs at multiple steps during BIR, thus participating in the destabilization of the genome by generating complex chromosomal rearrangements.
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Affiliation(s)
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Sevilla, Spain
- * E-mail:
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17
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SLX-1 is required for maintaining genomic integrity and promoting meiotic noncrossovers in the Caenorhabditis elegans germline. PLoS Genet 2012; 8:e1002888. [PMID: 22927825 PMCID: PMC3426554 DOI: 10.1371/journal.pgen.1002888] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 06/24/2012] [Indexed: 12/24/2022] Open
Abstract
Although the SLX4 complex, which includes structure-specific nucleases such as XPF, MUS81, and SLX1, plays important roles in the repair of several kinds of DNA damage, the function of SLX1 in the germline remains unknown. Here we characterized the endonuclease activities of the Caenorhabditis elegans SLX-1-HIM-18/SLX-4 complex co-purified from human 293T cells and determined SLX-1 germline function via analysis of slx-1(tm2644) mutants. SLX-1 shows a HIM-18/SLX-4–dependent endonuclease activity toward replication forks, 5′-flaps, and Holliday junctions. slx-1 mutants exhibit hypersensitivity to UV, nitrogen mustard, and camptothecin, but not gamma irradiation. Consistent with a role in DNA repair, recombination intermediates accumulate in both mitotic and meiotic germ cells in slx-1 mutants. Importantly, meiotic crossover distribution, but not crossover frequency, is altered on chromosomes in slx-1 mutants compared to wild type. This alteration is not due to changes in either the levels or distribution of double-strand breaks (DSBs) along chromosomes. We propose that SLX-1 is required for repair at stalled or collapsed replication forks, interstrand crosslink repair, and nucleotide excision repair during mitosis. Moreover, we hypothesize that SLX-1 regulates the crossover landscape during meiosis by acting as a noncrossover-promoting factor in a subset of DSBs. Crossover formation between homologous chromosomes is important for generating genetic diversity in subsequent generations, as well as for promoting accurate chromosome segregation during meiosis, which is a specialized cell division program that results in the formation of haploid gametes (sperm and eggs) from diploid parental germ cells. In the nematode Caenorhabditis elegans, a single off-centered crossover is formed on the chromosome arms between every pair of homologous chromosomes. Crossover formation at the central region of the chromosomes is suppressed by unknown mechanisms. By using high-resolution 3-D microscopy, we found that, while crossover distribution is biased to the arm regions along the chromosomes, DNA double-strand breaks (DSBs), which initiate the homologous recombination repair process, are evenly distributed along the chromosomes. These results suggest the existence of mechanisms that inhibit crossover formation after induction of DSBs at the central region of the chromosomes. In this study, our findings lead us to hypothesize that SLX-1, a structure-specific endonuclease, inhibits crossover formation at the central region of the chromosomes, probably via its resolution activity of the Holliday junctions, which are four-stranded recombination intermediates, to produce noncrossover products.
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18
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Steinacher R, Osman F, Dalgaard JZ, Lorenz A, Whitby MC. The DNA helicase Pfh1 promotes fork merging at replication termination sites to ensure genome stability. Genes Dev 2012; 26:594-602. [PMID: 22426535 DOI: 10.1101/gad.184663.111] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bidirectionally moving DNA replication forks merge at termination sites composed of accidental or programmed DNA-protein barriers. If merging fails, then regions of unreplicated DNA can result in the breakage of DNA during mitosis, which in turn can give rise to genome instability. Despite its importance, little is known about the mechanisms that promote the final stages of fork merging in eukaryotes. Here we show that the Pif1 family DNA helicase Pfh1 plays a dual role in promoting replication fork termination. First, it facilitates replication past DNA-protein barriers, and second, it promotes the merging of replication forks. A failure of these processes in Pfh1-deficient cells results in aberrant chromosome segregation and heightened genome instability.
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Affiliation(s)
- Roland Steinacher
- Department of Biochemistry, University of Oxford, Oxford OX13QU, United Kingdom
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19
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Maki K, Inoue T, Onaka A, Hashizume H, Somete N, Kobayashi Y, Murakami S, Shigaki C, Takahashi TS, Masukata H, Nakagawa T. Abundance of prereplicative complexes (Pre-RCs) facilitates recombinational repair under replication stress in fission yeast. J Biol Chem 2011; 286:41701-41710. [PMID: 21971174 DOI: 10.1074/jbc.m111.285619] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mcm2-7 complexes are loaded onto chromatin with the aid of Cdt1 and Cdc18/Cdc6 and form prereplicative complexes (pre-RCs) at multiple sites on each chromosome. Pre-RCs are essential for DNA replication and surviving replication stress. However, the mechanism by which pre-RCs contribute to surviving replication stress is largely unknown. Here, we isolated the fission yeast mcm6-S1 mutant that was hypersensitive to methyl methanesulfonate (MMS) and camptothecin (CPT), both of which cause forks to collapse. The mcm6-S1 mutation impaired the interaction with Cdt1 and decreased the binding of minichromosome maintenance (MCM) proteins to replication origins. Overexpression of Cdt1 restored MCM binding and suppressed the sensitivity to MMS and CPT, suggesting that the Cdt1-Mcm6 interaction is important for the assembly of pre-RCs and the repair of collapsed forks. MMS-induced Chk1 phosphorylation and Rad22/Rad52 focus formation occurred normally, whereas cells containing Rhp54/Rad54 foci, which are involved in DNA strand exchange and dissociation of the joint molecules, were increased. Remarkably, G(1) phase extension through deletion of an S phase cyclin, Cig2, as well as Cdt1 overexpression restored pre-RC assembly and suppressed Rhp54 accumulation. A cdc18 mutation also caused hypersensitivity to MMS and CPT and accumulation of Rhp54 foci. These data suggest that an abundance of pre-RCs facilitates a late step in the recombinational repair of collapsed forks in the following S phase.
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Affiliation(s)
- Kentaro Maki
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takahiro Inoue
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Atsushi Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hiroko Hashizume
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Naoko Somete
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yuko Kobayashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Shigefumi Murakami
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Chikako Shigaki
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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20
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Sofueva S, Osman F, Lorenz A, Steinacher R, Castagnetti S, Ledesma J, Whitby MC. Ultrafine anaphase bridges, broken DNA and illegitimate recombination induced by a replication fork barrier. Nucleic Acids Res 2011; 39:6568-84. [PMID: 21576223 PMCID: PMC3159475 DOI: 10.1093/nar/gkr340] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Most DNA double-strand breaks (DSBs) in S- and G2-phase cells are repaired accurately by Rad51-dependent sister chromatid recombination. However, a minority give rise to gross chromosome rearrangements (GCRs), which can result in disease/death. What determines whether a DSB is repaired accurately or inaccurately is currently unclear. We provide evidence that suggests that perturbing replication by a non-programmed protein-DNA replication fork barrier results in the persistence of replication intermediates (most likely regions of unreplicated DNA) into mitosis, which results in anaphase bridge formation and ultimately to DNA breakage. However, unlike previously characterised replication-associated DSBs, these breaks are repaired mainly by Rad51-independent processes such as single-strand annealing, and are therefore prone to generate GCRs. These data highlight how a replication-associated DSB can be predisposed to give rise to genome rearrangements in eukaryotes.
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Affiliation(s)
- Sevil Sofueva
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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21
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Schwartz EK, Heyer WD. Processing of joint molecule intermediates by structure-selective endonucleases during homologous recombination in eukaryotes. Chromosoma 2011; 120:109-27. [PMID: 21369956 PMCID: PMC3057012 DOI: 10.1007/s00412-010-0304-7] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 12/04/2010] [Accepted: 12/07/2010] [Indexed: 10/27/2022]
Abstract
Homologous recombination is required for maintaining genomic integrity by functioning in high-fidelity repair of DNA double-strand breaks and other complex lesions, replication fork support, and meiotic chromosome segregation. Joint DNA molecules are key intermediates in recombination and their differential processing determines whether the genetic outcome is a crossover or non-crossover event. The Holliday model of recombination highlights the resolution of four-way DNA joint molecules, termed Holliday junctions, and the bacterial Holliday junction resolvase RuvC set the paradigm for the mechanism of crossover formation. In eukaryotes, much effort has been invested in identifying the eukaryotic equivalent of bacterial RuvC, leading to the discovery of a number of DNA endonucleases, including Mus81-Mms4/EME1, Slx1-Slx4/BTBD12/MUS312, XPF-ERCC1, and Yen1/GEN1. These nucleases exert different selectivity for various DNA joint molecules, including Holliday junctions. Their mutant phenotypes and distinct species-specific characteristics expose a surprisingly complex system of joint molecule processing. In an attempt to reconcile the biochemical and genetic data, we propose that nicked junctions constitute important in vivo recombination intermediates whose processing determines the efficiency and outcome (crossover/non-crossover) of homologous recombination.
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Affiliation(s)
- Erin K. Schwartz
- Department of Microbiology, University of California—Davis, Davis, CA 95616 USA
| | - Wolf-Dietrich Heyer
- Department of Microbiology, University of California—Davis, Davis, CA 95616 USA
- Department of Molecular and Cellular Biology, University of California—Davis, Davis, CA 95616 USA
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22
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Svendsen JM, Harper JW. GEN1/Yen1 and the SLX4 complex: Solutions to the problem of Holliday junction resolution. Genes Dev 2010; 24:521-36. [PMID: 20203129 PMCID: PMC2841330 DOI: 10.1101/gad.1903510] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chromosomal double-strand breaks (DSBs) are considered to be among the most deleterious DNA lesions found in eukaryotic cells due to their propensity to promote genome instability. DSBs occur as a result of exogenous or endogenous DNA damage, and also occur during meiotic recombination. DSBs are often repaired through a process called homologous recombination (HR), which employs the sister chromatid in mitotic cells or the homologous chromosome in meiotic cells, as a template for repair. HR frequently involves the formation and resolution of four-way DNA structures referred to as the Holliday junction (HJ). Despite extensive study, the machinery and mechanisms used to process these structures in eukaryotes have remained poorly understood. Recent work has identified XPG and UvrC/GIY domain-containing structure-specific endonucleases that can symmetrically cleave HJs in vitro in a manner that allows for religation without additional processing, properties that are reminiscent of the classical RuvC HJ resolvase in bacteria. Genetic studies reveal potential roles for these HJ resolvases in repair after DNA damage and during meiosis. The stage is now set for a more comprehensive understanding of the specific roles these enzymes play in the response of cells to DSBs, collapsed replication forks, telomere dysfunction, and meiotic recombination.
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Affiliation(s)
- Jennifer M. Svendsen
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - J. Wade Harper
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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23
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Abstract
The six Saccharomyces cerevisiae SLX genes were identified in a screen for factors required for the viability of cells lacking Sgs1, a member of the RecQ helicase family involved in processing stalled replisomes and in the maintenance of genome stability. The six SLX gene products form three distinct heterodimeric complexes, and all three have catalytic activity. Slx3-Slx2 (also known as Mus81-Mms4) and Slx1-Slx4 are both heterodimeric endonucleases with a marked specificity for branched replication fork-like DNA species, whereas Slx5-Slx8 is a SUMO (small ubiquitin-related modifier)-targeted E3 ubiquitin ligase. All three complexes play important, but distinct, roles in different aspects of the cellular response to DNA damage and perturbed DNA replication. Slx4 interacts physically not only with Slx1, but also with Rad1-Rad10 [XPF (xeroderma pigmentosum complementation group F)-ERCC1 (excision repair cross-complementing 1) in humans], another structure-specific endonuclease that participates in the repair of UV-induced DNA damage and in a subpathway of recombinational DNA DSB (double-strand break) repair. Curiously, Slx4 is essential for repair of DSBs by Rad1-Rad10, but is not required for repair of UV damage. Slx4 also promotes cellular resistance to DNA-alkylating agents that block the progression of replisomes during DNA replication, by facilitating the error-free mode of lesion bypass. This does not require Slx1 or Rad1-Rad10, and so Slx4 has several distinct roles in protecting genome stability. In the present article, I provide an overview of our current understanding of the cellular roles of the Slx proteins, paying particular attention to the advances that have been made in understanding the cellular roles of Slx4. In particular, protein-protein interactions and underlying molecular mechanisms are discussed and I draw attention to the many questions that have yet to be answered.
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24
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Muñoz IM, Hain K, Déclais AC, Gardiner M, Toh GW, Sanchez-Pulido L, Heuckmann JM, Toth R, Macartney T, Eppink B, Kanaar R, Ponting CP, Lilley DMJ, Rouse J. Coordination of structure-specific nucleases by human SLX4/BTBD12 is required for DNA repair. Mol Cell 2009; 35:116-27. [PMID: 19595721 DOI: 10.1016/j.molcel.2009.06.020] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/19/2009] [Accepted: 06/23/2009] [Indexed: 10/20/2022]
Abstract
Budding yeast Slx4 interacts with the structure-specific endonuclease Slx1 to ensure completion of ribosomal DNA replication. Slx4 also interacts with the Rad1-Rad10 endonuclease to control cleavage of 3' flaps during repair of double-strand breaks (DSBs). Here we describe the identification of human SLX4, a scaffold for DNA repair nucleases XPF-ERCC1, MUS81-EME1, and SLX1. SLX4 immunoprecipitates show SLX1-dependent nuclease activity toward Holliday junctions and MUS81-dependent activity toward other branched DNA structures. Furthermore, SLX4 enhances the nuclease activity of SLX1, MUS81, and XPF. Consistent with a role in processing recombination intermediates, cells depleted of SLX4 are hypersensitive to genotoxins that cause DSBs and show defects in the resolution of interstrand crosslink-induced DSBs. Depletion of SLX4 causes a decrease in DSB-induced homologous recombination. These data show that SLX4 is a regulator of structure-specific nucleases and that SLX4 and SLX1 are important regulators of genome stability in human cells.
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Affiliation(s)
- Ivan M Muñoz
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
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25
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Miyabe I, Morishita T, Shinagawa H, Carr AM. Schizosaccharomyces pombe Cds1Chk2 regulates homologous recombination at stalled replication forks through the phosphorylation of recombination protein Rad60. J Cell Sci 2009; 122:3638-43. [PMID: 19755492 DOI: 10.1242/jcs.046508] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Schizosaccharomyces pombe rad60 gene is essential for cell growth and is involved in repairing DNA double-strand breaks. Rad60 physically interacts with, and is functionally related to, the structural maintenance of chromosomes 5 and 6 protein complex (Smc5/6). Rad60 is phosphorylated in response to hydroxyurea (HU)-induced DNA replication arrest in a Cds1(Chk2)-dependent manner. Rad60 localizes in nucleus in unchallenged cells, but becomes diffused throughout the cell in response to HU. To understand the role of Rad60 phosphorylation, we mutated the putative phosphorylation target motifs of Cds1(Chk2) and have identified two Cds1(Chk2) target residues responsible for Rad60 dispersal in response to HU. We show that the phosphorylation-defective rad60 mutation partially suppresses HU sensitivity and the elevated recombination frequency of smc6-X. Our data suggest that Rad60 phosphorylation is required to regulate homologous recombination at stalled replication forks, probably by regulating Smc5/6.
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Affiliation(s)
- Izumi Miyabe
- Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK
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26
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Fekairi S, Scaglione S, Chahwan C, Taylor ER, Tissier A, Coulon S, Dong MQ, Ruse C, Yates JR, Russell P, Fuchs RP, McGowan CH, Gaillard PHL. Human SLX4 is a Holliday junction resolvase subunit that binds multiple DNA repair/recombination endonucleases. Cell 2009; 138:78-89. [PMID: 19596236 DOI: 10.1016/j.cell.2009.06.029] [Citation(s) in RCA: 323] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 06/09/2009] [Accepted: 06/19/2009] [Indexed: 10/20/2022]
Abstract
Structure-specific endonucleases resolve DNA secondary structures generated during DNA repair and recombination. The yeast 5' flap endonuclease Slx1-Slx4 has received particular attention with the finding that Slx4 has Slx1-independent key functions in genome maintenance. Although Slx1 is a highly conserved protein in eukaryotes, no orthologs of Slx4 were reported other than in fungi. Here we report the identification of Slx4 orthologs in metazoa, including fly MUS312, essential for meiotic recombination, and human BTBD12, an ATM/ATR checkpoint kinase substrate. Human SLX1-SLX4 displays robust Holliday junction resolvase activity in addition to 5' flap endonuclease activity. Depletion of SLX1 and SLX4 results in 53BP1 foci accumulation and H2AX phosphorylation as well as cellular hypersensitivity to MMS. Furthermore, we show that SLX4 binds the XPF(ERCC4) and MUS81 subunits of the XPF-ERCC1 and MUS81-EME1 endonucleases and is required for DNA interstrand crosslink repair. We propose that SLX4 acts as a docking platform for multiple structure-specific endonucleases.
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Affiliation(s)
- Samira Fekairi
- Genome Instability and Carcinogenesis UPR3081 CNRS, Conventionné par l'Université d'Aix-Marseille 2, IGC, IMM 31 chemin Joseph Aiguier, 13402 Marseille, France
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27
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Irmisch A, Ampatzidou E, Mizuno K, O'Connell MJ, Murray JM. Smc5/6 maintains stalled replication forks in a recombination-competent conformation. EMBO J 2009; 28:144-55. [PMID: 19158664 DOI: 10.1038/emboj.2008.273] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/02/2008] [Indexed: 01/01/2023] Open
Abstract
The Smc5/6 structural maintenance of chromosomes complex is required for efficient homologous recombination (HR). Defects in Smc5/6 result in chromosome mis-segregation and fragmentation. By characterising two Schizosaccharomyces pombe smc6 mutants, we define two separate functions for Smc5/6 in HR. The first represents the previously described defect in processing recombination-dependent DNA intermediates when replication forks collapse, which leads to increased rDNA recombination. The second novel function defines Smc5/6 as a positive regulator of recombination in the rDNA and correlates mechanistically with a requirement to load RPA and Rad52 onto chromatin genome-wide when replication forks are stably stalled by nucleotide depletion. Rad52 is required for all HR repair, but Rad52 loading in response to replication fork stalling is unexpected and does not correlate with damage-induced foci. We propose that Smc5/6 is required to maintain stalled forks in a stable recombination-competent conformation primed for replication restart.
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Affiliation(s)
- Anja Irmisch
- Genome Damage and Stability Centre, University of Sussex, Brighton, E. Sussex, UK
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The Schizosaccharomyces pombe Pfh1p DNA helicase is essential for the maintenance of nuclear and mitochondrial DNA. Mol Cell Biol 2008; 28:6594-608. [PMID: 18725402 DOI: 10.1128/mcb.00191-08] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Schizosaccharomyces pombe Pfh1p is an essential member of the Pif family of 5'-3' DNA helicases. The two Saccharomyces cerevisiae homologs, Pif1p and Rrm3p, function in nuclear DNA replication, telomere length regulation, and mitochondrial genome integrity. We demonstrate here the existence of multiple Pfh1p isoforms that localized to either nuclei or mitochondria. The catalytic activity of Pfh1p was essential in both cellular compartments. The absence of nuclear Pfh1p resulted in G(2) arrest and accumulation of DNA damage foci, a finding suggestive of an essential role in DNA replication. Exogenous DNA damage resulted in localization of Pfh1p to DNA damage foci, suggesting that nuclear Pfh1p also functions in DNA repair. The absence of mitochondrial Pfh1p caused rapid depletion of mitochondrial DNA. Despite localization to nuclei and mitochondria in S. pombe, neither of the S. cerevisiae homologs, nor human PIF1, suppressed the lethality of pfh1Delta cells. However, the essential nuclear function of Pfh1p could be supplied by Rrm3p. Expression of Rrm3p suppressed the accumulation of DNA damage foci but not the hydroxyurea sensitivity of cells depleted of nuclear Pfh1p. Together, these data demonstrate that Pfh1p has essential roles in the replication of both nuclear and mitochondrial DNA.
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The Rad52 homologs Rad22 and Rti1 of Schizosaccharomyces pombe are not essential for meiotic interhomolog recombination, but are required for meiotic intrachromosomal recombination and mating-type-related DNA repair. Genetics 2008; 178:2399-412. [PMID: 18430957 DOI: 10.1534/genetics.107.085696] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins of the RAD52 epistasis group play an essential role in repair of some types of DNA damage and genetic recombination. In Schizosaccharomyces pombe, Rad22 (a Rad52 ortholog) has been shown to be as necessary for repair and recombination events during vegetative growth as its Saccharomyces cerevisiae counterpart. This finding contrasts with previous reports where, due to suppressor mutations in the fbh1 gene, rad22 mutants did not display a severe defect. We have analyzed the roles of Rad22 and Rti1, another Rad52 homolog, during meiotic recombination and meiosis in general. Both proteins play an important role in spore viability. During meiotic prophase I, they partially colocalize and partially localize to Rad51 foci and linear elements. Genetic analysis showed that meiotic interchromosomal crossover and conversion events were unexpectedly not much affected by deletion of either or both genes. A strong decrease of intrachromosomal recombination assayed by a gene duplication construct was observed. Therefore, we propose that the most important function of Rad22 and Rti1 in S. pombe meiosis is repair of double-strand breaks with involvement of the sister chromatids. In addition, a novel mating-type-related repair function of Rad22 specific to meiosis and spore germination is described.
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Nucleolar localization and dynamic roles of flap endonuclease 1 in ribosomal DNA replication and damage repair. Mol Cell Biol 2008; 28:4310-9. [PMID: 18443037 DOI: 10.1128/mcb.00200-08] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite the wealth of information available on the biochemical functions and our recent findings of its roles in genome stability and cancer avoidance of the structure-specific flap endonuclease 1 (FEN1), its cellular compartmentalization and dynamics corresponding to its involvement in various DNA metabolic pathways are not yet elucidated. Several years ago, we demonstrated that FEN1 migrates into the nucleus in response to DNA damage and under certain cell cycle conditions. In the current paper, we found that FEN1 is superaccumulated in the nucleolus and plays a role in the resolution of stalled DNA replication forks formed at the sites of natural replication fork barriers. In response to UV irradiation and upon phosphorylation, FEN1 migrates to nuclear plasma to participate in the resolution of UV cross-links on DNA, most likely employing its concerted action of exonuclease and gap-dependent endonuclease activities. Based on yeast complementation experiments, the mutation of Ser(187)Asp, mimicking constant phosphorylation, excludes FEN1 from nucleolar accumulation. The replacement of Ser(187) by Ala, eliminating the only phosphorylation site, retains FEN1 in nucleoli. Both of the mutations cause UV sensitivity, impair cellular UV damage repair capacity, and decline overall cellular survivorship.
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Roberts TM, Zaidi IW, Vaisica JA, Peter M, Brown GW. Regulation of rtt107 recruitment to stalled DNA replication forks by the cullin rtt101 and the rtt109 acetyltransferase. Mol Biol Cell 2007; 19:171-80. [PMID: 17978089 DOI: 10.1091/mbc.e07-09-0961] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
RTT107 (ESC4, YHR154W) encodes a BRCA1 C-terminal domain protein that is important for recovery from DNA damage during S phase. Rtt107 is a substrate of the checkpoint kinase Mec1, and it forms complexes with DNA repair enzymes, including the nuclease subunit Slx4, but the role of Rtt107 in the DNA damage response remains unclear. We find that Rtt107 interacts with chromatin when cells are treated with compounds that cause replication forks to arrest. This damage-dependent chromatin binding requires the acetyltransferase Rtt109, but it does not require acetylation of the known Rtt109 target, histone H3-K56. Chromatin binding of Rtt107 also requires the cullin Rtt101, which seems to play a direct role in Rtt107 recruitment, because the two proteins are found in complex with each other. Finally, we provide evidence that Rtt107 is bound at or near stalled replication forks in vivo. Together, these results indicate that Rtt109, Rtt101, and Rtt107, which genetic evidence suggests are functionally related, form a DNA damage response pathway that recruits Rtt107 complexes to damaged or stalled replication forks.
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Affiliation(s)
- Tania M Roberts
- Department of Biochemistry and Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
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Fersht N, Hermand D, Hayles J, Nurse P. Cdc18/CDC6 activates the Rad3-dependent checkpoint in the fission yeast. Nucleic Acids Res 2007; 35:5323-37. [PMID: 17690116 PMCID: PMC2018612 DOI: 10.1093/nar/gkm527] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A screen for genes that can ectopically activate a Rad3-dependent checkpoint block over mitosis in fission yeast has identified the DNA replication initiation factor cdc18 (known as CDC6 in other organisms). Either a stabilized form of Cdc18, the Cdc18-T6A phosphorylation mutant, or overexpression of wild type Cdc18, activate the Rad3-dependent S-M checkpoint in the apparent absence of detectable replication structures and gross DNA damage. This cell cycle block relies on the Rad checkpoint pathway and requires Chk1 phosphorylation and activation. Unexpectedly, Cdc18-T6A induces changes in the mobility of Chromosome III, affecting the size of a restriction fragment containing rDNA repeats and producing aberrant nucleolar structures. Recombination events within the rDNA appear to contribute at least in part to the cell cycle delay. We propose that an elevated level of Cdc18 activates the Rad3-dependent checkpoint either directly or indirectly, and additionally causes expansion of the rDNA repeats on Chromosome III.
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Affiliation(s)
- Naomi Fersht
- Cell Cycle Group, Cancer Research UK London Institute, London WC2A 3PX, UK.
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