1
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Tatsukawa K, Sakamoto R, Kawasoe Y, Kubota Y, Tsurimoto T, Takahashi T, Ohashi E. Resection of DNA double-strand breaks activates Mre11-Rad50-Nbs1- and Rad9-Hus1-Rad1-dependent mechanisms that redundantly promote ATR checkpoint activation and end processing in Xenopus egg extracts. Nucleic Acids Res 2024; 52:3146-3163. [PMID: 38349040 PMCID: PMC11014350 DOI: 10.1093/nar/gkae082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/21/2024] [Accepted: 01/29/2024] [Indexed: 04/14/2024] Open
Abstract
Sensing and processing of DNA double-strand breaks (DSBs) are vital to genome stability. DSBs are primarily detected by the ATM checkpoint pathway, where the Mre11-Rad50-Nbs1 (MRN) complex serves as the DSB sensor. Subsequent DSB end resection activates the ATR checkpoint pathway, where replication protein A, MRN, and the Rad9-Hus1-Rad1 (9-1-1) clamp serve as the DNA structure sensors. ATR activation depends also on Topbp1, which is loaded onto DNA through multiple mechanisms. While different DNA structures elicit specific ATR-activation subpathways, the regulation and mechanisms of the ATR-activation subpathways are not fully understood. Using DNA substrates that mimic extensively resected DSBs, we show here that MRN and 9-1-1 redundantly stimulate Dna2-dependent long-range end resection and ATR activation in Xenopus egg extracts. MRN serves as the loading platform for ATM, which, in turn, stimulates Dna2- and Topbp1-loading. Nevertheless, MRN promotes Dna2-mediated end processing largely independently of ATM. 9-1-1 is dispensable for bulk Dna2 loading, and Topbp1 loading is interdependent with 9-1-1. ATR facilitates Mre11 phosphorylation and ATM dissociation. These data uncover that long-range end resection activates two redundant pathways that facilitate ATR checkpoint signaling and DNA processing in a vertebrate system.
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Affiliation(s)
- Kensuke Tatsukawa
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Reihi Sakamoto
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yoshitaka Kawasoe
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yumiko Kubota
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Toshiki Tsurimoto
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tatsuro S Takahashi
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Eiji Ohashi
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga 526-0829, Japan
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2
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Hara K, Tatsukawa K, Nagata K, Iida N, Hishiki A, Ohashi E, Hashimoto H. Structural basis for intra- and intermolecular interactions on RAD9 subunit of 9-1-1 checkpoint clamp implies functional 9-1-1 regulation by RHINO. J Biol Chem 2024; 300:105751. [PMID: 38354779 PMCID: PMC10937111 DOI: 10.1016/j.jbc.2024.105751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/03/2024] [Accepted: 02/06/2024] [Indexed: 02/16/2024] Open
Abstract
Eukaryotic DNA clamp is a trimeric protein featuring a toroidal ring structure that binds DNA on the inside of the ring and multiple proteins involved in DNA transactions on the outside. Eukaryotes have two types of DNA clamps: the replication clamp PCNA and the checkpoint clamp RAD9-RAD1-HUS1 (9-1-1). 9-1-1 activates the ATR-CHK1 pathway in DNA damage checkpoint, regulating cell cycle progression. Structure of 9-1-1 consists of two moieties: a hetero-trimeric ring formed by PCNA-like domains of three subunits and an intrinsically disordered C-terminal region of the RAD9 subunit, called RAD9 C-tail. The RAD9 C-tail interacts with the 9-1-1 ring and disrupts the interaction between 9-1-1 and DNA, suggesting a negative regulatory role for this intramolecular interaction. In contrast, RHINO, a 9-1-1 binding protein, interacts with both RAD1 and RAD9 subunits, positively regulating checkpoint activation by 9-1-1. This study presents a biochemical and structural analysis of intra- and inter-molecular interactions on the 9-1-1 ring. Biochemical analysis indicates that RAD9 C-tail binds to the hydrophobic pocket on the PCNA-like domain of RAD9, implying that the pocket is involved in multiple protein-protein interactions. The crystal structure of the 9-1-1 ring in complex with a RHINO peptide reveals that RHINO binds to the hydrophobic pocket of RAD9, shedding light on the RAD9-binding motif. Additionally, the study proposes a structural model of the 9-1-1-RHINO quaternary complex. Together, these findings provide functional insights into the intra- and inter-molecular interactions on the front side of RAD9, elucidating the roles of RAD9 C-tail and RHINO in checkpoint activation.
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Affiliation(s)
- Kodai Hara
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Kensuke Tatsukawa
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan
| | - Kiho Nagata
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Nao Iida
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Asami Hishiki
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Eiji Ohashi
- Faculty of Science, Department of Biology, Kyushu University, Fukuoka, Japan; Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Hiroshi Hashimoto
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
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3
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Zheng F, Yao NY, Georgescu RE, Li H, O’Donnell ME. Structure of the PCNA unloader Elg1-RFC. SCIENCE ADVANCES 2024; 10:eadl1739. [PMID: 38427736 PMCID: PMC10906927 DOI: 10.1126/sciadv.adl1739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
During DNA replication, the proliferating cell nuclear antigen (PCNA) clamps are loaded onto primed sites for each Okazaki fragment synthesis by the AAA+ heteropentamer replication factor C (RFC). PCNA encircling duplex DNA is quite stable and is removed from DNA by the dedicated clamp unloader Elg1-RFC. Here, we show the cryo-EM structure of Elg1-RFC in various states with PCNA. The structures reveal essential features of Elg1-RFC that explain how it is dedicated to PCNA unloading. Specifically, Elg1 contains two external loops that block opening of the Elg1-RFC complex for DNA binding, and an "Elg1 plug" domain that fills the central DNA binding chamber, thereby reinforcing the exclusive PCNA unloading activity of Elg1-RFC. Elg1-RFC was capable of unloading PCNA using non-hydrolyzable AMP-PNP. Both RFC and Elg1-RFC could remove PCNA from covalently closed circular DNA, indicating that PCNA unloading occurs by a mechanism that is distinct from PCNA loading. Implications for the PCNA unloading mechanism are discussed.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Nina Y. Yao
- DNA Replication Laboratory and Howard Hughes Medical Institute, The Rockefeller University, NY, New York, USA
| | - Roxana E. Georgescu
- DNA Replication Laboratory and Howard Hughes Medical Institute, The Rockefeller University, NY, New York, USA
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Michael E. O’Donnell
- DNA Replication Laboratory and Howard Hughes Medical Institute, The Rockefeller University, NY, New York, USA
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4
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Fousek-Schuller VJ, Borgstahl GEO. The Intriguing Mystery of RPA Phosphorylation in DNA Double-Strand Break Repair. Genes (Basel) 2024; 15:167. [PMID: 38397158 PMCID: PMC10888239 DOI: 10.3390/genes15020167] [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: 12/20/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Human Replication Protein A (RPA) was historically discovered as one of the six components needed to reconstitute simian virus 40 DNA replication from purified components. RPA is now known to be involved in all DNA metabolism pathways that involve single-stranded DNA (ssDNA). Heterotrimeric RPA comprises several domains connected by flexible linkers and is heavily regulated by post-translational modifications (PTMs). The structure of RPA has been challenging to obtain. Various structural methods have been applied, but a complete understanding of RPA's flexible structure, its function, and how it is regulated by PTMs has yet to be obtained. This review will summarize recent literature concerning how RPA is phosphorylated in the cell cycle, the structural analysis of RPA, DNA and protein interactions involving RPA, and how PTMs regulate RPA activity and complex formation in double-strand break repair. There are many holes in our understanding of this research area. We will conclude with perspectives for future research on how RPA PTMs control double-strand break repair in the cell cycle.
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Affiliation(s)
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer & Allied Diseases, UNMC, Omaha, NE 68198-6805, USA
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5
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Becker CJ, Cigliola V, Gillotay P, Rich A, De Simone A, Han Y, Di Talia S, Poss KD. In toto imaging of glial JNK signaling during larval zebrafish spinal cord regeneration. Development 2023; 150:dev202076. [PMID: 37997694 PMCID: PMC10753585 DOI: 10.1242/dev.202076] [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: 06/12/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023]
Abstract
Identification of signaling events that contribute to innate spinal cord regeneration in zebrafish can uncover new targets for modulating injury responses of the mammalian central nervous system. Using a chemical screen, we identify JNK signaling as a necessary regulator of glial cell cycling and tissue bridging during spinal cord regeneration in larval zebrafish. With a kinase translocation reporter, we visualize and quantify JNK signaling dynamics at single-cell resolution in glial cell populations in developing larvae and during injury-induced regeneration. Glial JNK signaling is patterned in time and space during development and regeneration, decreasing globally as the tissue matures and increasing in the rostral cord stump upon transection injury. Thus, dynamic and regional regulation of JNK signaling help to direct glial cell behaviors during innate spinal cord regeneration.
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Affiliation(s)
- Clayton J. Becker
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Valentina Cigliola
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Université Côte d’Azur, Inserm, CNRS, Institut de Biologie Valrose, 06100 Nice, France
| | - Pierre Gillotay
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashley Rich
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Alessandro De Simone
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Yanchao Han
- Department of Cardiovascular Surgery of the First Affiliated Hospital & Institute for Cardiovascular Science, Suzhou Medical College, Soochow University, Suzhou, 215006 Jiangsu, China
| | - Stefano Di Talia
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kenneth D. Poss
- Duke Regeneration Center and Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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6
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Casari E, Pizzul P, Rinaldi C, Gnugnoli M, Clerici M, Longhese MP. The PP2A phosphatase counteracts the function of the 9-1-1 axis in checkpoint activation. Cell Rep 2023; 42:113360. [PMID: 38007689 DOI: 10.1016/j.celrep.2023.113360] [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: 06/03/2023] [Revised: 09/25/2023] [Accepted: 10/13/2023] [Indexed: 11/27/2023] Open
Abstract
DNA damage elicits a checkpoint response depending on the Mec1/ATR kinase, which detects the presence of single-stranded DNA and activates the effector kinase Rad53/CHK2. In Saccharomyces cerevisiae, one of the signaling circuits leading to Rad53 activation involves the evolutionarily conserved 9-1-1 complex, which acts as a platform for the binding of Dpb11 and Rad9 (referred to as the 9-1-1 axis) to generate a protein complex that allows Mec1 activation. By examining the effects of both loss-of-function and hypermorphic mutations, here, we show that the Cdc55 and Tpd3 subunits of the PP2A phosphatase counteract activation of the 9-1-1 axis. The lack of this inhibitory function results in DNA-damage sensitivity, sustained checkpoint-mediated cell-cycle arrest, and impaired resection of DNA double-strand breaks. This PP2A anti-checkpoint role depends on the capacity of Cdc55 to interact with Ddc1 and to counteract Ddc1-Dpb11 complex formation by preventing Dpb11 recognition of Ddc1 phosphorylated on Thr602.
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Affiliation(s)
- Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Marco Gnugnoli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy.
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7
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Zhou FY, Waterman DP, Caban-Penix S, Memisoglu G, Eapen VV, Haber JE. Prolonged Cell Cycle Arrest in Response to DNA damage in Yeast Requires the Maintenance of DNA Damage Signaling and the Spindle Assembly Checkpoint. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.15.540538. [PMID: 37292675 PMCID: PMC10245577 DOI: 10.1101/2023.05.15.540538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cells evoke the DNA damage checkpoint (DDC) to inhibit mitosis in the presence of DNA double-strand breaks (DSBs) to allow more time for DNA repair. In budding yeast, a single irreparable DSB is sufficient to activate the DDC and induce cell cycle arrest prior to anaphase for about 12 to 15 hours, after which cells "adapt" to the damage by extinguishing the DDC and resuming the cell cycle. While activation of the DNA damage-dependent cell cycle arrest is well-understood, how it is maintained remains unclear. To address this, we conditionally depleted key DDC proteins after the DDC was fully activated and monitored changes in the maintenance of cell cycle arrest. Degradation of Ddc2 ATRIP , Rad9, Rad24, or Rad53 CHK2 results in premature resumption of the cell cycle, indicating that these DDC factors are required both to establish and to maintain the arrest. Dun1 is required for establishment, but not maintenance of arrest, whereas Chk1 is required for prolonged maintenance but not for initial establishment of the mitotic arrest. When the cells are challenged with 2 persistent DSBs, they remain permanently arrested. This permanent arrest is initially dependent on the continuous presence of Ddc2 and Rad53; however, after 15 hours both proteins become dispensable. Instead, the continued mitotic arrest is sustained by spindle-assembly checkpoint (SAC) proteins Mad1, Mad2, and Bub2 but not by Bub2's binding partner Bfa1. These data suggest that prolonged cell cycle arrest in response to 2 DSBs is achieved by a handoff from the DDC to specific components of the SAC. Furthermore, the establishment and maintenance of DNA damage-induced cell cycle arrest requires overlapping but different sets of factors.
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8
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Zheng F, Georgescu RE, Yao NY, O'Donnell ME, Li H. Structures of 9-1-1 DNA checkpoint clamp loading at gaps from start to finish and ramification on biology. Cell Rep 2023; 42:112694. [PMID: 37392384 PMCID: PMC10529453 DOI: 10.1016/j.celrep.2023.112694] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/01/2023] [Accepted: 06/09/2023] [Indexed: 07/03/2023] Open
Abstract
Rad24-RFC (replication factor C) loads the 9-1-1 checkpoint clamp onto the recessed 5' ends by binding a 5' DNA at an external surface site and threading the 3' single-stranded DNA (ssDNA) into 9-1-1. We find here that Rad24-RFC loads 9-1-1 onto DNA gaps in preference to a recessed 5' end, thus presumably leaving 9-1-1 on duplex 3' ss/double-stranded DNA (dsDNA) after Rad24-RFC ejects from DNA. We captured five Rad24-RFC-9-1-1 loading intermediates using a 10-nt gap DNA. We also determined the structure of Rad24-RFC-9-1-1 using a 5-nt gap DNA. The structures reveal that Rad24-RFC is unable to melt DNA ends and that a Rad24 loop limits the dsDNA length in the chamber. These observations explain Rad24-RFC's preference for a preexisting gap of over 5-nt ssDNA and suggest a direct role of the 9-1-1 in gap repair with various TLS (trans-lesion synthesis) polymerases in addition to signaling the ATR kinase.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Roxana E Georgescu
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Nina Y Yao
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Michael E O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA; Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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9
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Xu YJ, Bhadra S, Mahdi ATA, Dev K, Yurtsever I, Nakamura TM. Comprehensive mutational analysis of the checkpoint signaling function of Rpa1/Ssb1 in fission yeast. PLoS Genet 2023; 19:e1010691. [PMID: 37200372 DOI: 10.1371/journal.pgen.1010691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/31/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023] Open
Abstract
Replication protein A (RPA) is a heterotrimeric complex and the major single-strand DNA (ssDNA) binding protein in eukaryotes. It plays important roles in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling. Because RPA is essential for cell survival, understanding its checkpoint signaling function in cells has been challenging. Several RPA mutants have been reported previously in fission yeast. None of them, however, has a defined checkpoint defect. A separation-of-function mutant of RPA, if identified, would provide significant insights into the checkpoint initiation mechanisms. We have explored this possibility and carried out an extensive genetic screen for Rpa1/Ssb1, the large subunit of RPA in fission yeast, looking for mutants with defects in checkpoint signaling. This screen has identified twenty-five primary mutants that are sensitive to genotoxins. Among these mutants, two have been confirmed partially defective in checkpoint signaling primarily at the replication fork, not the DNA damage site. The remaining mutants are likely defective in other functions such as DNA repair or telomere maintenance. Our screened mutants, therefore, provide a valuable tool for future dissection of the multiple functions of RPA in fission yeast.
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Affiliation(s)
- Yong-Jie Xu
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Sankhadip Bhadra
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Alaa Taha A Mahdi
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Kamal Dev
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Ilknur Yurtsever
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Toru M Nakamura
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of America
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10
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Zheng F, Georgescu RE, Yao NY, O’Donnell ME, Li H. Structures of 9-1-1 DNA checkpoint clamp loading at gaps from start to finish and ramification to biology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539266. [PMID: 37205533 PMCID: PMC10187155 DOI: 10.1101/2023.05.03.539266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Recent structural studies show the Rad24-RFC loads the 9-1-1 checkpoint clamp onto a recessed 5' end by binding the 5' DNA on Rad24 at an external surface site and threading the 3' ssDNA into the well-established internal chamber and into 9-1-1. We find here that Rad24-RFC loads 9-1-1 onto DNA gaps in preference to a recessed 5' DNA end, thus presumably leaving 9-1-1 on a 3' ss/ds DNA after Rad24-RFC ejects from the 5' gap end and may explain reports of 9-1-1 directly functioning in DNA repair with various TLS polymerases, in addition to signaling the ATR kinase. To gain a deeper understanding of 9-1-1 loading at gaps we report high-resolution structures of Rad24-RFC during loading of 9-1-1 onto 10-nt and 5-nt gapped DNAs. At a 10-nt gap we captured five Rad24-RFC-9-1-1 loading intermediates in which the 9-1-1 DNA entry gate varies from fully open to fully closed around DNA using ATPγS, supporting the emerging view that ATP hydrolysis is not needed for clamp opening/closing, but instead for dissociation of the loader from the clamp encircling DNA. The structure of Rad24-RFC-9-1-1 at a 5-nt gap shows a 180° axially rotated 3'-dsDNA which orients the template strand to bridge the 3'- and 5'- junctions with a minimum 5-nt ssDNA. The structures reveal a unique loop on Rad24 that limits the length of dsDNA in the inner chamber, and inability to melt DNA ends unlike RFC, thereby explaining Rad24-RFC's preference for a preexisting ssDNA gap and suggesting a direct role in gap repair in addition to its checkpoint role.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA
| | - Roxana E. Georgescu
- DNA Replication Laboratory, The Rockefeller University, New York, New York, USA
| | - Nina Y. Yao
- DNA Replication Laboratory, The Rockefeller University, New York, New York, USA
| | - Michael E. O’Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, New York, USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA
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11
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Garribba L, De Feudis G, Martis V, Galli M, Dumont M, Eliezer Y, Wardenaar R, Ippolito MR, Iyer DR, Tijhuis AE, Spierings DCJ, Schubert M, Taglietti S, Soriani C, Gemble S, Basto R, Rhind N, Foijer F, Ben-David U, Fachinetti D, Doksani Y, Santaguida S. Short-term molecular consequences of chromosome mis-segregation for genome stability. Nat Commun 2023; 14:1353. [PMID: 36906648 PMCID: PMC10008630 DOI: 10.1038/s41467-023-37095-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 03/01/2023] [Indexed: 03/13/2023] Open
Abstract
Chromosome instability (CIN) is the most common form of genome instability and is a hallmark of cancer. CIN invariably leads to aneuploidy, a state of karyotype imbalance. Here, we show that aneuploidy can also trigger CIN. We found that aneuploid cells experience DNA replication stress in their first S-phase and precipitate in a state of continuous CIN. This generates a repertoire of genetically diverse cells with structural chromosomal abnormalities that can either continue proliferating or stop dividing. Cycling aneuploid cells display lower karyotype complexity compared to the arrested ones and increased expression of DNA repair signatures. Interestingly, the same signatures are upregulated in highly-proliferative cancer cells, which might enable them to proliferate despite the disadvantage conferred by aneuploidy-induced CIN. Altogether, our study reveals the short-term origins of CIN following aneuploidy and indicates the aneuploid state of cancer cells as a point mutation-independent source of genome instability, providing an explanation for aneuploidy occurrence in tumors.
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Affiliation(s)
- Lorenza Garribba
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Giuseppina De Feudis
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Valentino Martis
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Martina Galli
- IFOM ETS - The AIRC Institute of Molecular Oncology, via Adamello 16, 20139, Milan, Italy
| | - Marie Dumont
- Institut Curie, PSL Research University, CNRS, UMR144, Paris, France
| | - Yonatan Eliezer
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - René Wardenaar
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, the Netherlands
| | - Marica Rosaria Ippolito
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Divya Ramalingam Iyer
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA, 01605, USA
| | - Andréa E Tijhuis
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, the Netherlands
| | - Diana C J Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, the Netherlands
| | - Michael Schubert
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, the Netherlands
| | - Silvia Taglietti
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Chiara Soriani
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy
| | - Simon Gemble
- Institut Curie, PSL Research University, CNRS, UMR144, Paris, France
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS, UMR144, Paris, France
| | - Nick Rhind
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA, 01605, USA
| | - Floris Foijer
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, the Netherlands
| | - Uri Ben-David
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Ylli Doksani
- IFOM ETS - The AIRC Institute of Molecular Oncology, via Adamello 16, 20139, Milan, Italy
| | - Stefano Santaguida
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy.
- Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9/1, 20122, Milan, Italy.
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12
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Xu YJ, Bhadra S, Mahdi ATA, Dev K, Yurtsever I, Nakamura TM. Comprehensive mutational analysis of the checkpoint signaling function of Rpa1/Ssb1 in fission yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531248. [PMID: 36945624 PMCID: PMC10028789 DOI: 10.1101/2023.03.06.531248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Replication protein A (RPA) is a heterotrimeric complex and the major single-strand DNA (ssDNA) binding protein in eukaryotes. It plays important roles in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling. Because RPA is essential for cell survival, understanding its checkpoint signaling function in cells has been challenging. Several RPA mutants have been reported previously in fission yeast. None of them, however, has a defined checkpoint defect. A separation-of-function mutant of RPA, if identified, would provide significant insights into the checkpoint initiation mechanisms. We have explored this possibility and carried out an extensive genetic screening for Rpa1/Ssb1, the large subunit of RPA in fission yeast, looking for mutants with defects in checkpoint signaling. This screen has identified twenty-five primary mutants that are sensitive to genotoxins. Among these mutants, two have been confirmed partially defective in checkpoint signaling primarily at the replication fork, not the DNA damage site. The remaining mutants are likely defective in other functions such as DNA repair or telomere maintenance. Our screened mutants, therefore, provide a valuable tool for future dissection of the multiple functions of RPA in fission yeast. AUTHOR SUMMARY Originally discovered as a protein required for replication of simian virus SV40 DNA, replication protein A is now known to function in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling in all eukaryotes. The protein is a complex of three subunits and the two larger ones are essential for cell growth. This essential function however complicates the studies in living cells, and for this reason, its checkpoint function remains to be fully understood. We have carried out an genetic screening of the largest subunit of this protein in fission yeast, aiming to find a non-lethal mutant that lacks the checkpoint function. This extensive screen has uncovered two mutants with a partial defect in checkpoint signaling when DNA replication is arrested. Surprisingly, although the two mutants also have a defect in DNA repair, their checkpoint signaling remains largely functional in the presence of DNA damage. We have also uncovered twenty-three mutants with defects in DNA repair or telomere maintenance, but not checkpoint signaling. Therefore, the non-lethal mutants uncovered by this study provide a valuable tool for dissecting the multiple functions of this biologically important protein in fission yeast.
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13
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Gospodinov A, Dzhokova S, Petrova M, Ugrinova I. Chromatin regulators in DNA replication and genome stability maintenance during S-phase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 135:243-280. [PMID: 37061334 DOI: 10.1016/bs.apcsb.2023.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
The duplication of genetic information is central to life. The replication of genetic information is strictly controlled to ensure that each piece of genomic DNA is copied only once during a cell cycle. Factors that slow or stop replication forks cause replication stress. Replication stress is a major source of genome instability in cancer cells. Multiple control mechanisms facilitate the unimpeded fork progression, prevent fork collapse and coordinate fork repair. Chromatin alterations, caused by histone post-translational modifications and chromatin remodeling, have critical roles in normal replication and in avoiding replication stress and its consequences. This text reviews the chromatin regulators that ensure DNA replication and the proper response to replication stress. We also briefly touch on exploiting replication stress in therapeutic strategies. As chromatin regulators are frequently mutated in cancer, manipulating their activity could provide many possibilities for personalized treatment.
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Affiliation(s)
- Anastas Gospodinov
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
| | - Stefka Dzhokova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Maria Petrova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Iva Ugrinova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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14
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Acharya N, Prakash L, Prakash S. Yeast 9-1-1 complex acts as a sliding clamp for DNA synthesis by DNA polymerase ε. J Biol Chem 2023; 299:102727. [PMID: 36410434 PMCID: PMC9791402 DOI: 10.1016/j.jbc.2022.102727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/10/2022] [Accepted: 11/13/2022] [Indexed: 11/21/2022] Open
Abstract
Eukaryotic cells harbor two DNA-binding clamps, proliferating cell nuclear antigen (PCNA), and another clamp commonly referred to as 9-1-1 clamp. In contrast to the essential role of PCNA in DNA replication as a sliding clamp for DNA polymerase (Pol) δ, no such role in DNA synthesis has been identified for the human 9-1-1 clamp or the orthologous yeast 17-3-1 clamp. The only role identified for either the 9-1-1 or 17-3-1 clamp is in the recruitment of signal transduction kinases, which affect the activation of cell cycle checkpoints in response to DNA damage. However, unlike the loading of PCNA by the replication factor C (RFC) clamp loader onto 3'-recessed DNA junctions for processive DNA synthesis by Polδ, the 17-3-1 clamp or the 9-1-1 clamp is loaded by their respective clamp loader Rad24-RFC or RAD17-RFC onto the 5'-recessed DNA junction of replication protein A-coated DNA for the recruitment of signal transduction kinases. Here, we identify a novel role of 17-3-1 clamp as a sliding clamp for DNA synthesis by Polε. We provide evidence that similar to the loading of PCNA by RFC, the 17-3-1 clamp is loaded by the Rad24-RFC clamp loader at the 3'-recessed DNA junction in an ATP-dependent manner. However, unlike PCNA, the 17-3-1 clamp does not enhance the processivity of DNA synthesis by Polε; instead, it greatly increases the catalytic efficiency of Polε for correct nucleotide incorporation. Furthermore, we show that the same PCNA-interacting peptide domain in the polymerase 2 catalytic subunit mediates Polε interaction with the 17-3-1 clamp and with PCNA.
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Affiliation(s)
- Narottam Acharya
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Louise Prakash
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Satya Prakash
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA.
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15
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Li H, O'Donnell M, Kelch B. Unexpected new insights into DNA clamp loaders: Eukaryotic clamp loaders contain a second DNA site for recessed 5' ends that facilitates repair and signals DNA damage: Eukaryotic clamp loaders contain a second DNA site for recessed 5' ends that facilitates repair and signals DNA damage. Bioessays 2022; 44:e2200154. [PMID: 36116108 PMCID: PMC9927785 DOI: 10.1002/bies.202200154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 12/15/2022]
Abstract
Clamp loaders are pentameric AAA+ assemblies that use ATP to open and close circular DNA sliding clamps around DNA. Clamp loaders show homology in all organisms, from bacteria to human. The eukaryotic PCNA clamp is loaded onto 3' primed DNA by the replication factor C (RFC) hetero-pentameric clamp loader. Eukaryotes also have three alternative RFC-like clamp loaders (RLCs) in which the Rfc1 subunit is substituted by another protein. One of these is the yeast Rad24-RFC (Rad17-RFC in human) that loads a 9-1-1 heterotrimer clamp onto a recessed 5' end of DNA. Recent structural studies of Rad24-RFC have discovered an unexpected 5' DNA binding site on the outside of the clamp loader and reveal how a 5' end can be utilized for loading the 9-1-1 clamp onto DNA. In light of these results, new studies reveal that RFC also contains a 5' DNA binding site, which functions in gap repair. These studies also reveal many new features of clamp loaders. As reviewed herein, these recent studies together have transformed our view of the clamp loader mechanism.
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Affiliation(s)
- Huilin Li
- Department of Structural BiologyVan Andel InstituteGrand RapidsMichiganUSA
| | - Mike O'Donnell
- DNA Replication LaboratoryThe Rockefeller UniversityNew YorkNew YorkUSA,Howard Hughes Medical InstituteThe Rockefeller UniversityNew YorkNew YorkUSA
| | - Brian Kelch
- Department of Biochemistry and Molecular BiotechnologyUniversity of Massachusetts Chan Medical SchoolWorcesterMassachusettsUSA
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16
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ASPM promotes ATR-CHK1 activation and stabilizes stalled replication forks in response to replication stress. Proc Natl Acad Sci U S A 2022; 119:e2203783119. [PMID: 36161901 PMCID: PMC9546549 DOI: 10.1073/pnas.2203783119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
ASPM (encoded by MCPH5) is a frequently mutated protein, and such mutations occur in >40% of cases of primary microcephaly (MCPH). Here, we characterize a function of ASPM in DNA replication and the replication stress response. ASPM serves as a scaffold to load stimulators required for ATR-CHK1 checkpoint signaling upon replication stress, which protects stalled replication forks from degradation. ASPM deficiency leads to genomic instability and the sensitization of cancer cells to replication stressors. ASPM is a protein encoded by primary microcephaly 5 (MCPH5) and is responsible for ensuring spindle position during mitosis and the symmetrical division of neural stem cells. We recently reported that ASPM promotes homologous recombination (HR) repair of DNA double strand breaks. However, its potential role in DNA replication and replication stress response remains elusive. Interestingly, we found that ASPM is dispensable for DNA replication under unperturbed conditions. However, ASPM is enriched at stalled replication forks in a RAD17-dependent manner in response to replication stress and promotes RAD9 and TopBP1 loading onto chromatin, facilitating ATR-CHK1 activation. ASPM depletion results in failed fork restart and nuclease MRE11-mediated nascent DNA degradation at the stalled replication fork. The overall consequence is chromosome instability and the sensitization of cancer cells to replication stressors. These data support a role for ASPM in loading RAD17-RAD9/TopBP1 onto chromatin to activate the ATR-CHK1 checkpoint and ultimately ensure genome stability.
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17
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Day M, Oliver AW, Pearl LH. Structure of the human RAD17-RFC clamp loader and 9-1-1 checkpoint clamp bound to a dsDNA-ssDNA junction. Nucleic Acids Res 2022; 50:8279-8289. [PMID: 35819203 PMCID: PMC9371934 DOI: 10.1093/nar/gkac588] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 11/14/2022] Open
Abstract
The RAD9-RAD1-HUS1 (9-1-1) clamp forms one half of the DNA damage checkpoint system that signals the presence of substantial regions of single-stranded DNA arising from replication fork collapse or resection of DNA double strand breaks. Loaded at the 5'-recessed end of a dsDNA-ssDNA junction by the RAD17-RFC clamp loader complex, the phosphorylated C-terminal tail of the RAD9 subunit of 9-1-1 engages with the mediator scaffold TOPBP1 which in turn activates the ATR kinase, localised through the interaction of its constitutive partner ATRIP with RPA-coated ssDNA. Using cryogenic electron microscopy (cryoEM) we have determined the structure of a complex of the human RAD17-RFC clamp loader bound to human 9-1-1, engaged with a dsDNA-ssDNA junction. The structure answers the key questions of how RAD17 confers specificity for 9-1-1 over PCNA, and how the clamp loader specifically recognises the recessed 5' DNA end and fixes the orientation of 9-1-1 on the ssDNA.
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Affiliation(s)
- Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW1E 6BT, UK
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18
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DNA binding by the Rad9A subunit of the Rad9-Rad1-Hus1 complex. PLoS One 2022; 17:e0272645. [PMID: 35939452 PMCID: PMC9359528 DOI: 10.1371/journal.pone.0272645] [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] [Received: 02/14/2022] [Accepted: 07/22/2022] [Indexed: 11/19/2022] Open
Abstract
The Rad9-Rad1-Hus1 checkpoint clamp activates the DNA damage response and promotes DNA repair. DNA loading on the central channel of the Rad9-Rad1-Hus1 complex is required to execute its biological functions. Because Rad9A has the highest DNA affinity among the three subunits, we determined the domains and functional residues of human Rad9A that are critical for DNA interaction. The N-terminal globular domain (residues 1–133) had 3.7-fold better DNA binding affinity than the C-terminal globular domain (residues 134–266) of Rad9A1-266. Rad9A1-266 binds DNA 16-, 60-, and 30-fold better than Rad9A1-133, Rad9A134-266, and Rad9A94-266, respectively, indicating that different regions cooperatively contribute to DNA binding. We show that basic residues including K11, K15, R22, K78, K220, and R223 are important for DNA binding. The reductions on DNA binding of Ala substituted mutants of these basic residues show synergistic effect and are dependent on their residential Rad9A deletion constructs. Interestingly, deletion of a loop (residues 160–163) of Rad9A94-266 weakens DNA binding activity by 4.1-fold as compared to wild-type (WT) Rad9A94-266. Cellular sensitivity to genotoxin of rad9A knockout cells is restored by expressing WT-Rad9Afull. However, rad9A knockout cells expressing Rad9A mutants defective in DNA binding are more sensitive to H2O2 as compared to cells expressing WT-Rad9Afull. Only the rad9A knockout cells expressing loop-deleted Rad9A mutant are more sensitive to hydroxyurea than cells expressing WT-Rad9A. In addition, Rad9A-DNA interaction is required for DNA damage signaling activation. Our results indicate that DNA association by Rad9A is critical for maintaining cell viability and checkpoint activation under stress.
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19
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Schrecker M, Castaneda JC, Devbhandari S, Kumar C, Remus D, Hite RK. Multistep loading of a DNA sliding clamp onto DNA by replication factor C. eLife 2022; 11:e78253. [PMID: 35939393 PMCID: PMC9359705 DOI: 10.7554/elife.78253] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
The DNA sliding clamp proliferating cell nuclear antigen (PCNA) is an essential co-factor for many eukaryotic DNA metabolic enzymes. PCNA is loaded around DNA by the ATP-dependent clamp loader replication factor C (RFC), which acts at single-stranded (ss)/double-stranded DNA (dsDNA) junctions harboring a recessed 3' end (3' ss/dsDNA junctions) and at DNA nicks. To illuminate the loading mechanism we have investigated the structure of RFC:PCNA bound to ATPγS and 3' ss/dsDNA junctions or nicked DNA using cryogenic electron microscopy. Unexpectedly, we observe open and closed PCNA conformations in the RFC:PCNA:DNA complex, revealing that PCNA can adopt an open, planar conformation that allows direct insertion of dsDNA, and raising the question of whether PCNA ring closure is mechanistically coupled to ATP hydrolysis. By resolving multiple DNA-bound states of RFC:PCNA we observe that partial melting facilitates lateral insertion into the central channel formed by RFC:PCNA. We also resolve the Rfc1 N-terminal domain and demonstrate that its single BRCT domain participates in coordinating DNA prior to insertion into the central RFC channel, which promotes PCNA loading on the lagging strand of replication forks in vitro. Combined, our data suggest a comprehensive and fundamentally revised model for the RFC-catalyzed loading of PCNA onto DNA.
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Affiliation(s)
- Marina Schrecker
- Structural Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Juan C Castaneda
- Weill Cornell Medicine Graduate School, Weill Cornell MedicineNew YorkUnited States
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Sujan Devbhandari
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Charanya Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
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20
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Zheng F, Georgescu RE, Yao NY, Li H, O'Donnell ME. Cryo-EM structures reveal that RFC recognizes both the 3'- and 5'-DNA ends to load PCNA onto gaps for DNA repair. eLife 2022; 11:77469. [PMID: 35829698 PMCID: PMC9293004 DOI: 10.7554/elife.77469] [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: 01/31/2022] [Accepted: 06/06/2022] [Indexed: 12/27/2022] Open
Abstract
RFC uses ATP to assemble PCNA onto primed sites for replicative DNA polymerases d and e. The RFC pentamer forms a central chamber that binds 3' ss/ds DNA junctions to load PCNA onto DNA during replication. We show here five structures that identify a 2nd DNA binding site in RFC that binds a 5' duplex. This 5' DNA site is located between the N-terminal BRCT domain and AAA+ module of the large Rfc1 subunit. Our structures reveal ideal binding to a 7-nt gap, which includes 2 bp unwound by the clamp loader. Biochemical studies show enhanced binding to 5 and 10 nt gaps, consistent with the structural results. Because both 3' and 5' ends are present at a ssDNA gap, we propose that the 5' site facilitates RFC's PCNA loading activity at a DNA damage-induced gap to recruit gap-filling polymerases. These findings are consistent with genetic studies showing that base excision repair of gaps greater than 1 base requires PCNA and involves the 5' DNA binding domain of Rfc1. We further observe that a 5' end facilitates PCNA loading at an RPA coated 30-nt gap, suggesting a potential role of the RFC 5'-DNA site in lagging strand DNA synthesis.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Roxana E Georgescu
- DNA Replication Laboratory, Rockefeller University, New York, United States
| | - Nina Y Yao
- DNA Replication Laboratory, Rockefeller University, New York, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Michael E O'Donnell
- Howard Hughes Medical Institute, Rockefeller University, New York, United States
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21
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Liu X, Gaubitz C, Pajak J, Kelch BA. A second DNA binding site on RFC facilitates clamp loading at gapped or nicked DNA. eLife 2022; 11:77483. [PMID: 35731107 PMCID: PMC9293009 DOI: 10.7554/elife.77483] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Clamp loaders place circular sliding clamp proteins onto DNA so that clamp-binding partner proteins can synthesize, scan, and repair the genome. DNA with nicks or small single-stranded gaps are common clamp-loading targets in DNA repair, yet these substrates would be sterically blocked given the known mechanism for binding of primer-template DNA. Here, we report the discovery of a second DNA binding site in the yeast clamp loader replication factor C (RFC) that aids in binding to nicked or gapped DNA. This DNA binding site is on the external surface and is only accessible in the open conformation of RFC. Initial DNA binding at this site thus provides access to the primary DNA binding site in the central chamber. Furthermore, we identify that this site can partially unwind DNA to create an extended single-stranded gap for DNA binding in RFC’s central chamber and subsequent ATPase activation. Finally, we show that deletion of the BRCT domain, a major component of the external DNA binding site, results in defective yeast growth in the presence of DNA damage where nicked or gapped DNA intermediates occur. We propose that RFC’s external DNA binding site acts to enhance DNA binding and clamp loading, particularly at DNA architectures typically found in DNA repair.
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Affiliation(s)
- Xingchen Liu
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, United States
| | - Christl Gaubitz
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, United States
| | - Joshua Pajak
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, United States
| | - Brian A Kelch
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, United States
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22
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Smc5/6 Complex Promotes Rad3 ATR Checkpoint Signaling at the Perturbed Replication Fork through Sumoylation of the RecQ Helicase Rqh1. Mol Cell Biol 2022; 42:e0004522. [PMID: 35612306 DOI: 10.1128/mcb.00045-22] [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] [Indexed: 11/20/2022] Open
Abstract
Smc5/6, like cohesin and condensin, is a structural maintenance of chromosomes complex crucial for genome stability. Unlike cohesin and condensin, Smc5/6 carries an essential Nse2 subunit with SUMO E3 ligase activity. While screening for new DNA replication checkpoint mutants in fission yeast, we have identified two previously uncharacterized mutants in Smc5/6. Characterization of the mutants and a series of previously reported Smc5/6 mutants uncovered that sumoylation of the RecQ helicase Rqh1 by Nse2 facilitates the checkpoint signaling at the replication fork. We found that mutations that eliminate the sumoylation sites or the helicase activity of Rqh1 compromised the checkpoint signaling similar to a nse2 mutant lacking the ligase activity. Surprisingly, introducing a sumoylation site mutation to a helicase-inactive rqh1 mutant promoted cell survival under stress. These findings, together with other genetic data, support a mechanism that sumoylation of Rqh1 by Smc5/6-Nse2 recruits Rqh1 or modulates its helicase activity at the fork to facilitate the checkpoint signaling. Since the Smc5/6 complex, Rqh1, and the replication checkpoint are conserved in eukaryotes, a similar checkpoint mechanism may be operating in human cells.
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23
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Mechanisms of loading and release of the 9-1-1 checkpoint clamp. Nat Struct Mol Biol 2022; 29:369-375. [PMID: 35314831 DOI: 10.1038/s41594-022-00741-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/09/2022] [Indexed: 01/14/2023]
Abstract
Single-stranded or double-stranded DNA junctions with recessed 5' ends serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATRMec1. However, the basis for 9-1-1's recruitment to 5' junctions is unclear. Here, we present structures of the yeast checkpoint clamp loader, Rad24-replication factor C (RFC), in complex with 9-1-1 and a 5' junction and in a post-ATP-hydrolysis state. Unexpectedly, 9-1-1 adopts both closed and planar open states in the presence of Rad24-RFC and DNA. Moreover, Rad24-RFC associates with the DNA junction in the opposite orientation of processivity clamp loaders with Rad24 exclusively coordinating the double-stranded region. ATP hydrolysis stimulates conformational changes in Rad24-RFC, leading to disengagement of DNA-loaded 9-1-1. Together, these structures explain 9-1-1's recruitment to 5' junctions and reveal new principles of sliding clamp loading.
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24
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The partner-swapping sliding clamp loader exposed. Nat Struct Mol Biol 2022; 29:283-286. [PMID: 35410371 DOI: 10.1038/s41594-022-00761-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Zheng F, Georgescu RE, Yao NY, O'Donnell ME, Li H. DNA is loaded through the 9-1-1 DNA checkpoint clamp in the opposite direction of the PCNA clamp. Nat Struct Mol Biol 2022; 29:376-385. [PMID: 35314830 PMCID: PMC9010301 DOI: 10.1038/s41594-022-00742-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 02/11/2022] [Indexed: 12/11/2022]
Abstract
The 9-1-1 DNA checkpoint clamp is loaded onto 5'-recessed DNA to activate the DNA damage checkpoint that arrests the cell cycle. The 9-1-1 clamp is a heterotrimeric ring that is loaded in Saccharomyces cerevisiae by Rad24-RFC (hRAD17-RFC), an alternate clamp loader in which Rad24 replaces Rfc1 in the RFC1-5 clamp loader of proliferating cell nuclear antigen (PCNA). The 9-1-1 clamp loading mechanism has been a mystery, because, unlike RFC, which loads PCNA onto a 3'-recessed junction, Rad24-RFC loads the 9-1-1 ring onto a 5'-recessed DNA junction. Here we report two cryo-EM structures of Rad24-RFC-DNA with a closed or 27-Å open 9-1-1 clamp. The structures reveal a completely unexpected mechanism by which a clamp can be loaded onto DNA. Unlike RFC, which encircles DNA, Rad24 binds 5'-DNA on its surface, not inside the loader, and threads the 3' ssDNA overhang into the 9-1-1 clamp from above the ring.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Roxana E Georgescu
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Nina Y Yao
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Michael E O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA.
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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26
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Tingler M, Philipp M, Burkhalter MD. DNA Replication proteins in primary microcephaly syndromes. Biol Cell 2022; 114:143-159. [PMID: 35182397 DOI: 10.1111/boc.202100061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 11/30/2022]
Abstract
SCOPE Improper expansion of neural stem and progenitor cells during brain development manifests in primary microcephaly. It is characterized by a reduced head circumference, which correlates with a reduction in brain size. This often corresponds to a general underdevelopment of the brain and entails cognitive, behavioral and motoric retardation. In the past decade significant research efforts have been undertaken to identify genes and the molecular mechanisms underlying microcephaly. One such gene set encompasses factors required for DNA replication. Intriguingly, a growing body of evidence indicates that a substantial number of these genes mediate faithful centrosome and cilium function in addition to their canonical function in genome duplication. Here, we summarize, which DNA replication factors are associated with microcephaly syndromes and to which extent they impact on centrosomes and cilia. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Melanie Tingler
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, 72074, Germany
| | - Melanie Philipp
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, 72074, Germany
| | - Martin D Burkhalter
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, 72074, Germany
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27
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Yoshida K, Fujita M. DNA damage responses that enhance resilience to replication stress. Cell Mol Life Sci 2021; 78:6763-6773. [PMID: 34463774 PMCID: PMC11072782 DOI: 10.1007/s00018-021-03926-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022]
Abstract
During duplication of the genome, eukaryotic cells may experience various exogenous and endogenous replication stresses that impede progression of DNA replication along chromosomes. Chemical alterations in template DNA, imbalances of deoxynucleotide pools, repetitive sequences, tight DNA-protein complexes, and conflict with transcription can negatively affect the replication machineries. If not properly resolved, stalled replication forks can cause chromosome breaks leading to genomic instability and tumor development. Replication stress is enhanced in cancer cells due, for example, to the loss of DNA repair genes or replication-transcription conflict caused by activation of oncogenic pathways. To prevent these serious consequences, cells are equipped with diverse mechanisms that enhance the resilience of replication machineries to replication stresses. This review describes DNA damage responses activated at stressed replication forks and summarizes current knowledge on the pathways that promote faithful chromosome replication and protect chromosome integrity, including ATR-dependent replication checkpoint signaling, DNA cross-link repair, and SLX4-mediated responses to tight DNA-protein complexes that act as barriers. This review also focuses on the relevance of replication stress responses to selective cancer chemotherapies.
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Affiliation(s)
- Kazumasa Yoshida
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
- Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Masatoshi Fujita
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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28
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Wong RP, Petriukov K, Ulrich HD. Daughter-strand gaps in DNA replication - substrates of lesion processing and initiators of distress signalling. DNA Repair (Amst) 2021; 105:103163. [PMID: 34186497 DOI: 10.1016/j.dnarep.2021.103163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 10/21/2022]
Abstract
Dealing with DNA lesions during genome replication is particularly challenging because damaged replication templates interfere with the progression of the replicative DNA polymerases and thereby endanger the stability of the replisome. A variety of mechanisms for the recovery of replication forks exist, but both bacteria and eukaryotic cells also have the option of continuing replication downstream of the lesion, leaving behind a daughter-strand gap in the newly synthesized DNA. In this review, we address the significance of these single-stranded DNA structures as sites of DNA damage sensing and processing at a distance from ongoing genome replication. We describe the factors controlling the emergence of daughter-strand gaps from stalled replication intermediates, the benefits and risks of their expansion and repair via translesion synthesis or recombination-mediated template switching, and the mechanisms by which they activate local as well as global replication stress signals. Our growing understanding of daughter-strand gaps not only identifies them as targets of fundamental genome maintenance mechanisms, but also suggests that proper control over their activities has important practical implications for treatment strategies and resistance mechanisms in cancer therapy.
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Affiliation(s)
- Ronald P Wong
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany
| | - Kirill Petriukov
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany.
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29
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Tannous EA, Burgers PM. Novel insights into the mechanism of cell cycle kinases Mec1(ATR) and Tel1(ATM). Crit Rev Biochem Mol Biol 2021; 56:441-454. [PMID: 34151669 DOI: 10.1080/10409238.2021.1925218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA replication is a highly precise process which usually functions in a perfect rhythm with cell cycle progression. However, cells are constantly faced with various kinds of obstacles such as blocks in DNA replication, lack of availability of precursors and improper chromosome alignment. When these problems are not addressed, they may lead to chromosome instability and the accumulation of mutations, and even cell death. Therefore, the cell has developed response mechanisms to keep most of these situations under control. Of the many factors that participate in this DNA damage response, members of the family of phosphatidylinositol 3-kinase-related protein kinases (PIKKs) orchestrate the response landscape. Our understanding of two members of the PIKK family, human ATR (yeast Mec1) and ATM (yeast Tel1), and their associated partner proteins, has shown substantial progress through recent biochemical and structural studies. Emerging structural information of these unique kinases show common features that reveal the mechanism of kinase activity.
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Affiliation(s)
- Elias A Tannous
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
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30
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Zhang J, Wang L, Xie X. RFC4 promotes the progression and growth of Oral Tongue squamous cell carcinoma in vivo and vitro. J Clin Lab Anal 2021; 35:e23761. [PMID: 33783864 PMCID: PMC8128301 DOI: 10.1002/jcla.23761] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/28/2021] [Accepted: 03/02/2021] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Currently, many studies have found that RFC4 was up-regulated in various cancers, and related to the progression and development. While the effects of RFC4 in oral tongue squamous cell carcinoma remain unclear, the main purpose of this research is to explore the role of RFC4 in oral tongue squamous cell carcinoma. METHODS The expression of RFC4 in various cancers was analyzed in GEPIA database, and the results were further verified by IHC assay. The relationship between RFC4 and several clinical parameters was analyzed; the proliferation was further observed by knockdown RFC4 in vitro. Finally, we constructed related nude mouse models by planting cells subcutaneous of nude mice, and the discrepancy was observed. RESULTS Based on GEPIA database, RFC4 was up-regulated in various cancers, including colorectal cancer, breast cancer, prostate cancer, lung cancer, and liver cancer. RFC4 was up-regulated in oral tongue squamous cell carcinoma compared with the normal tissue from GEPIA online database; we further found that the expression of RFC4 was tightly associated with TNM stage (p = 0.005), but not with age, gender, and differentiation (p > 0.05). We further found that the proliferation of oral tongue squamous cell carcinoma was obviously restrained in vitro, and the carcinogenesis was also inhibited in vivo. CONCLUSIONS We found that RFC4 was up-regulated and related to the progression of oral tongue squamous cell carcinoma, and knockdown RFC4 could restrain the proliferation and progression. RFC4 might serve a potential biomarker and provide a new treatment strategy for lots of patients with oral tongue squamous cell carcinoma.
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Affiliation(s)
- Jian Zhang
- Head and Neck Tumor SurgerySecond People's Hospital of Lianyungang CityLianyungang CityChina
| | - Linlin Wang
- The Department of OncologySecond People's Hospital of Lianyungang CityLianyungang CityChina
| | - Xiao Xie
- Head and Neck Tumor SurgerySecond People's Hospital of Lianyungang CityLianyungang CityChina
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31
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Ho K, Luo H, Zhu W, Tang Y. Critical role of SMG7 in activation of the ATR-CHK1 axis in response to genotoxic stress. Sci Rep 2021; 11:7502. [PMID: 33820915 PMCID: PMC8021557 DOI: 10.1038/s41598-021-86957-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/15/2021] [Indexed: 11/30/2022] Open
Abstract
CHK1 is a crucial DNA damage checkpoint kinase and its activation, which requires ATR and RAD17, leads to inhibition of DNA replication and cell cycle progression. Recently, we reported that SMG7 stabilizes and activates p53 to induce G1 arrest upon DNA damage; here we show that SMG7 plays a critical role in the activation of the ATR-CHK1 axis. Following genotoxic stress, SMG7-null cells exhibit deficient ATR signaling, indicated by the attenuated phosphorylation of CHK1 and RPA32, and importantly, unhindered DNA replication and fork progression. Through its 14-3-3 domain, SMG7 interacts directly with the Ser635-phosphorylated RAD17 and promotes chromatin retention of the 9-1-1 complex by the RAD17-RFC, an essential step to CHK1 activation. Furthermore, through maintenance of CHK1 activity, SMG7 controls G2-M transition and facilitates orderly cell cycle progression during recovery from replication stress. Taken together, our data reveals SMG7 as an indispensable signaling component in the ATR-CHK1 pathway during genotoxic stress response.
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Affiliation(s)
- Kathleen Ho
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY, 12208, USA
| | - Hongwei Luo
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY, 12208, USA
| | - Wei Zhu
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY, 12208, USA
- Key Laboratory of State Ethnic Affairs Commission for Biological Technology, College of Life Science, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Yi Tang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY, 12208, USA.
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32
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Peritore M, Reusswig KU, Bantele SCS, Straub T, Pfander B. Strand-specific ChIP-seq at DNA breaks distinguishes ssDNA versus dsDNA binding and refutes single-stranded nucleosomes. Mol Cell 2021; 81:1841-1853.e4. [PMID: 33651987 DOI: 10.1016/j.molcel.2021.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 12/30/2020] [Accepted: 01/29/2021] [Indexed: 02/07/2023]
Abstract
In a first step of DNA double-strand break (DSB) repair by homologous recombination, DNA ends are resected such that single-stranded DNA (ssDNA) overhangs are generated. ssDNA is specifically bound by RPA and other factors, which constitutes a ssDNA-domain on damaged chromatin. The molecular organization of this ssDNA and the adjacent dsDNA domain is crucial during DSB signaling and repair. However, data regarding the presence of nucleosomes, the most basic chromatin components, in the ssDNA domain have been contradictory. Here, we use site-specific induction of DSBs and chromatin immunoprecipitation followed by strand-specific sequencing to analyze in vivo binding of key DSB repair and signaling proteins to either the ssDNA or dsDNA domain. In the case of nucleosomes, we show that recently proposed ssDNA nucleosomes are not a major, persistent species, but that nucleosome eviction and DNA end resection are intrinsically coupled. These results support a model of separated dsDNA-nucleosome and ssDNA-RPA domains during DSB repair.
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Affiliation(s)
- Martina Peritore
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Karl-Uwe Reusswig
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Susanne C S Bantele
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Tobias Straub
- Biomedizinisches Centrum, Core Facility Bioinformatics, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany
| | - Boris Pfander
- Research Group DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
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33
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He Y, Hu S, Zhong J, Cheng A, Shan N. Identification of significant genes signatures and prognostic biomarkers in cervical squamous carcinoma via bioinformatic data. PeerJ 2020; 8:e10386. [PMID: 33344075 PMCID: PMC7718800 DOI: 10.7717/peerj.10386] [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: 07/28/2020] [Accepted: 10/27/2020] [Indexed: 12/26/2022] Open
Abstract
Background Cervical squamous cancer (CESC) is an intractable gynecological malignancy because of its high mortality rate and difficulty in early diagnosis. Several biomarkers have been found to predict the prognose of CESC using bioinformatics methods, but they still lack clinical effectiveness. Most of the existing bioinformatic studies only focus on the changes of oncogenes but neglect the differences on the protein level and molecular biology validation are rarely conducted. Methods Gene set data from the NCBI-GEO database were used in this study to compare the differences of gene and protein levels between normal and cancer tissues through significant pathway selection and core gene signature analysis to screen potential clinical biomarkers of CESC. Subsequently, the molecular and protein levels of clinical samples were verified by quantitative transcription PCR, western blot and immunohistochemistry. Results Three differentially expressed genes (RFC4, MCM2, TOP2A) were found to have a significant survival (P < 0.05) and highly expressed in CESC tissues. Molecular biological verification using quantitative reverse transcribed PCR, western blotting and immunohistochemistry assays exhibited significant differences in the expression of RFC4 between CESC and para-cancerous tissues (P < 0.05). Conclusion This study identified three potential biomarkers (RFC4, MCM2, TOP2A) of CESC which may be useful to clarify the underlying mechanisms of CESC and predict the prognosis of CESC patients.
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Affiliation(s)
- Yunan He
- Department of Gynecology and Obstetrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shunjie Hu
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jiaojiao Zhong
- Department of Dermatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Anran Cheng
- Department of Gynecology Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong, China
| | - Nianchun Shan
- Departmen of Gynecology and Obstetrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
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34
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Inhibitors of DNA double-strand break repair at the crossroads of cancer therapy and genome editing. Biochem Pharmacol 2020; 182:114195. [DOI: 10.1016/j.bcp.2020.114195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022]
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35
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Hu T, Shen H, Li J, Yang P, Gu Q, Fu Z. RFC2, a direct target of miR-744, modulates the cell cycle and promotes the proliferation of CRC cells. J Cell Physiol 2020; 235:8319-8333. [PMID: 32239691 DOI: 10.1002/jcp.29676] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/06/2020] [Indexed: 12/13/2022]
Abstract
Colorectal cancer (CRC) is a common digestive tract malignancy, which is characterized by high mortality, morbidity, and poor prognosis. Replication factor C subunit 2 (RFC2), one RFC family member, was reported to be related to various malignancies and plays an important role in proliferation, invasion, and metastasis. Nonetheless, the RFC2 biological role within CRC is still unknown. RFC2 expression profiles in CRC tissues were collected based on The Cancer Genome Atlas database, whereas miR-744 and RFC2 expression levels were detected in human CRC tissues. miR-744 and RFC2 effects on the proliferation of CRC were assessed both in vivo and in vitro. RFC2 was recognized to be a direct miR-744 target through luciferase reporter assay. RFC2 upregulation was observed within CRC tissues, and a high RFC2 level showed a correlation with poor clinicopathological symptoms. RFC2 knockdown inhibited CRC cell proliferation through promoting cell cycle arrest at the G1 phase, which was achieved by cyclin E2 (CCNE2) downregulation in vivo and in vitro. miR-744 was identified to be the tumor suppressor microRNA, which targeted RFC2 directly for inhibiting the proliferation of CRC cells both in vivo and in vitro. miR-744 downregulation was detected within CRC tissue, and messenger RNA expression showed a negative correlation with RFC2 expression within CRC tissues. Our study demonstrates that the miR-744/RFC2/CCNE2 axis potentially provides a candidate for a treatment strategy for CRC.
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Affiliation(s)
- Tao Hu
- The First College of Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Hengyang Shen
- The First College of Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Jie Li
- The First College of Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Peng Yang
- The First College of Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Qiou Gu
- The First College of Clinical Medicine, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Zan Fu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P.R. China
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Caldwell CC, Spies M. Dynamic elements of replication protein A at the crossroads of DNA replication, recombination, and repair. Crit Rev Biochem Mol Biol 2020; 55:482-507. [PMID: 32856505 PMCID: PMC7821911 DOI: 10.1080/10409238.2020.1813070] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 01/19/2023]
Abstract
The heterotrimeric eukaryotic Replication protein A (RPA) is a master regulator of numerous DNA metabolic processes. For a long time, it has been viewed as an inert protector of ssDNA and a platform for assembly of various genome maintenance and signaling machines. Later, the modular organization of the RPA DNA binding domains suggested a possibility for dynamic interaction with ssDNA. This modular organization has inspired several models for the RPA-ssDNA interaction that aimed to explain how RPA, the high-affinity ssDNA binding protein, is replaced by the downstream players in DNA replication, recombination, and repair that bind ssDNA with much lower affinity. Recent studies, and in particular single-molecule observations of RPA-ssDNA interactions, led to the development of a new model for the ssDNA handoff from RPA to a specific downstream factor where not only stability and structural rearrangements but also RPA conformational dynamics guide the ssDNA handoff. Here we will review the current knowledge of the RPA structure, its dynamic interaction with ssDNA, and how RPA conformational dynamics may be influenced by posttranslational modification and proteins that interact with RPA, as well as how RPA dynamics may be harnessed in cellular decision making.
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Affiliation(s)
- Colleen C. Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
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37
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Gobbini E, Casari E, Colombo CV, Bonetti D, Longhese MP. The 9-1-1 Complex Controls Mre11 Nuclease and Checkpoint Activation during Short-Range Resection of DNA Double-Strand Breaks. Cell Rep 2020; 33:108287. [DOI: 10.1016/j.celrep.2020.108287] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/08/2020] [Accepted: 09/28/2020] [Indexed: 12/17/2022] Open
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An ordered assembly of MYH glycosylase, SIRT6 protein deacetylase, and Rad9-Rad1-Hus1 checkpoint clamp at oxidatively damaged telomeres. Aging (Albany NY) 2020; 12:17761-17785. [PMID: 32991318 PMCID: PMC7585086 DOI: 10.18632/aging.103934] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/07/2020] [Indexed: 01/24/2023]
Abstract
In the base excision repair pathway, MYH/MUTYH DNA glycosylase prevents mutations by removing adenine mispaired with 8-oxoG, a frequent oxidative lesion. MYH glycosylase activity is enhanced by Rad9-Rad1-Hus1 (9-1-1) checkpoint clamp and SIRT6 histone/protein deacetylase. Here, we show that MYH, SIRT6, and 9-1-1 are recruited to confined oxidatively damaged regions on telomeres in mammalian cells. Using different knockout cells, we show that SIRT6 responds to damaged telomeres very early, and then recruits MYH and Hus1 following oxidative stress. However, the recruitment of Hus1 to damaged telomeres is partially dependent on SIRT6. The catalytic activities of SIRT6 are not important for SIRT6 response but are essential for MYH recruitment to damaged telomeres. Compared to wild-type MYH, the recruitment of hMYHV315A mutant (defective in both SIRT6 and Hus1 interactions), but not hMYHQ324H mutant (defective in Hus1 interaction only), to damaged telomeres is severely reduced. The formation of MYH/SIRT6/9-1-1 complex is of biological significance as interrupting their interactions can increase cell's sensitivity to H2O2 and/or elevate cellular 8-oxoG levels after H2O2 treatment. Our results establish that SIRT6 acts as an early sensor of BER enzymes and both SIRT6 and 9-1-1 serve critical roles in DNA repair to maintain telomere integrity.
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Rainey MD, Bennett D, O’Dea R, Zanchetta ME, Voisin M, Seoighe C, Santocanale C. ATR Restrains DNA Synthesis and Mitotic Catastrophe in Response to CDC7 Inhibition. Cell Rep 2020; 32:108096. [DOI: 10.1016/j.celrep.2020.108096] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 06/19/2020] [Accepted: 08/10/2020] [Indexed: 12/31/2022] Open
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40
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Benslimane Y, Bertomeu T, Coulombe-Huntington J, McQuaid M, Sánchez-Osuna M, Papadopoli D, Avizonis D, Russo MDST, Huard C, Topisirovic I, Wurtele H, Tyers M, Harrington L. Genome-Wide Screens Reveal that Resveratrol Induces Replicative Stress in Human Cells. Mol Cell 2020; 79:846-856.e8. [PMID: 32755594 DOI: 10.1016/j.molcel.2020.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 05/12/2020] [Accepted: 07/07/2020] [Indexed: 12/26/2022]
Abstract
Resveratrol is a natural product associated with wide-ranging effects in animal and cellular models, including lifespan extension. To identify the genetic target of resveratrol in human cells, we conducted genome-wide CRISPR-Cas9 screens to pinpoint genes that confer sensitivity or resistance to resveratrol. An extensive network of DNA damage response and replicative stress genes exhibited genetic interactions with resveratrol and its analog pterostilbene. These genetic profiles showed similarity to the response to hydroxyurea, an inhibitor of ribonucleotide reductase that causes replicative stress. Resveratrol, pterostilbene, and hydroxyurea caused similar depletion of nucleotide pools, inhibition of replication fork progression, and induction of replicative stress. The ability of resveratrol to inhibit cell proliferation and S phase transit was independent of the histone deacetylase sirtuin 1, which has been implicated in lifespan extension by resveratrol. These results establish that a primary impact of resveratrol on human cell proliferation is the induction of low-level replicative stress.
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Affiliation(s)
- Yahya Benslimane
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - Thierry Bertomeu
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - Jasmin Coulombe-Huntington
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - Mary McQuaid
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada
| | - María Sánchez-Osuna
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - David Papadopoli
- Gerald Bronfman Department of Oncology, Departments of Biochemistry and Experimental Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada
| | - Daina Avizonis
- Goodman Cancer Research Center, Metabolomics Core Facility, 1160 Pine Avenue West, Room 418, Montréal, QC H3A 1A3, Canada
| | - Mariana De Sa Tavares Russo
- Goodman Cancer Research Center, Metabolomics Core Facility, 1160 Pine Avenue West, Room 418, Montréal, QC H3A 1A3, Canada
| | - Caroline Huard
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - Ivan Topisirovic
- Gerald Bronfman Department of Oncology, Departments of Biochemistry and Experimental Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada
| | - Hugo Wurtele
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada
| | - Lea Harrington
- Institute for Research in Immunology and Cancer, Université de Montréal, PO Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada.
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Ho KH, Kuo TC, Lee YT, Chen PH, Shih CM, Cheng CH, Liu AJ, Lee CC, Chen KC. Xanthohumol regulates miR-4749-5p-inhibited RFC2 signaling in enhancing temozolomide cytotoxicity to glioblastoma. Life Sci 2020; 254:117807. [PMID: 32422304 DOI: 10.1016/j.lfs.2020.117807] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 02/01/2023]
Abstract
AIMS Xanthohumol (XN), a natural prenylated flavonoid isolated from Humulus lupulus L. (hops), possess the therapeutic effects in glioblastoma multiforme (GBM), which is a grade IV aggressive glioma in adults. However, low bioavailability and extractive yield limit the clinical applications of XN. To comprehensively investigate XN-mediated gene networks in inducing cell death is helpful for drug development and cancer research. Therefore, we aim to identify the detailed molecular mechanisms of XN's effects on exhibiting cytotoxicity for GBM therapy. METHODS AND KEY FINDINGS XN significantly induced GBM cell death and enhanced temozolomide (TMZ) cytotoxicity, a first-line therapeutic drug of GBM. XN-mediated transcriptome profiles and canonical pathways were identified. DNA repair signaling, a well-established mechanism against TMZ cytotoxicity, was significantly correlated with XN-downregulated genes. Replication factor C subunit 2 (RFC2), a DNA repair-related gene, was obviously downregulated in XN-treated cells. Higher RFC2 levels which occupied poor patient survival were also observed in high grade GBM patients and tumors. Inhibition of RFC2 reduced cell viability, induced cell apoptosis, and enhanced both XN and TMZ cytotoxicity. By intersecting array data, bioinformatic prediction, and in vitro experiments, microRNA (miR)-4749-5p, a XN-upregulated microRNA, was identified to target to RFC2 3'UTR and inhibited RFC2 expression. A negative correlation existed between miR-4749-5p and RFC2 in GBM patients. Overexpression of miR-4749-5p significantly promoted XN- and TMZ-mediated cytotoxicity, and reduced RFC2 levels. SIGNIFICANCE Consequently, we suggest that miR-4749-5p targeting RFC2 signaling participates in XN-enhanced TMZ cytotoxicity of GBM. Our findings provide new potential therapeutic directions for future GBM therapy.
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Affiliation(s)
- Kuo-Hao Ho
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Tai-Chih Kuo
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Yi-Ting Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Peng-Hsu Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Chwen-Ming Shih
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Chia-Hsiung Cheng
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan
| | - Ann-Jeng Liu
- Department of Neurosurgery, Taipei City Hospital Ren-Ai Branch, Taipei, Taiwan
| | - Chin-Cheng Lee
- Department of Pathology and Laboratory Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
| | - Ku-Chung Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taiwan.
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42
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Mahapatra K, Roy S. An insight into the mechanism of DNA damage response in plants- role of SUPPRESSOR OF GAMMA RESPONSE 1: An overview. Mutat Res 2020; 819-820:111689. [PMID: 32004947 DOI: 10.1016/j.mrfmmm.2020.111689] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/31/2019] [Accepted: 01/23/2020] [Indexed: 02/03/2023]
Abstract
Because of their sessile lifestyle, plants are inescapably exposed to various kinds of environmental stresses throughout their lifetime. Therefore, to regulate their growth and development, plants constantly monitor the environmental signals and respond appropriately. However, these environmental stress factors, along with some endogenous metabolites, generated in response to environmental stress factors often induce various forms of DNA damage in plants and thus promote genome instability. To maintain the genomic integrity, plants have developed an extensive, sophisticated and coordinated cellular signaling mechanism known as DNA damage response or DDR. DDR evokes a signaling process which initiates with the sensing of DNA damage and followed by the subsequent activation of downstream pathways in many directions to repair and eliminate the harmful effects of DNA damages. SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), one of the newly identified components of DDR in plant genome, appears to play central role in this signaling network. SOG1 is a member of NAC [NO APICAL MERISTEM (NAM), ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR (ATAF), CUP-SHAPED COTYLEDON (CUC)] domain family of transcription factors and involved in a diverse array of function in plants, encompassing transcriptional response to DNA damage, cell cycle checkpoint functions, ATAXIA-TELANGIECTASIA-MUTATED (ATM) or ATAXIA TELANGIECTASIA AND RAD3-RELATED (ATR) mediated activation of DNA damage response and repair, functioning in programmed cell death and regulation of induction of endoreduplication. Although most of the functional studies on SOG1 have been reported in Arabidopsis, some recent reports have indicated diverse functions of SOG1 in various other plant species, including Glycine max, Medicago truncatula, Sorghum bicolour, Oryza sativa and Zea mays, respectively. The remarkable functional diversity shown by SOG1 protein indicates its multitasking capacity. In this review, we integrate information mainly related to functional aspects of SOG1 in the context of DDR in plants. Considering the important role of SOG1 in DDR and its functional diversity, in-depth functional study of this crucial regulatory protein can provide further potential information on genome stability maintenance mechanism in plants in the context of changing environmental condition.
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Affiliation(s)
- Kalyan Mahapatra
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Golapbag Campus, Burdwan, 713 104, West Bengal, India
| | - Sujit Roy
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Golapbag Campus, Burdwan, 713 104, West Bengal, India.
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Chauhan N, Wagh V, Joshi P, Jariyal H. ATM and ATR checkpoint kinase pathways: A concise review. ADVANCES IN HUMAN BIOLOGY 2020. [DOI: 10.4103/aihb.aihb_78_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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44
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Functional interplay between the oxidative stress response and DNA damage checkpoint signaling for genome maintenance in aerobic organisms. J Microbiol 2019; 58:81-91. [DOI: 10.1007/s12275-020-9520-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/29/2019] [Accepted: 11/30/2019] [Indexed: 12/13/2022]
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45
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Matos DA, Zhang JM, Ouyang J, Nguyen HD, Genois MM, Zou L. ATR Protects the Genome against R Loops through a MUS81-Triggered Feedback Loop. Mol Cell 2019; 77:514-527.e4. [PMID: 31708417 DOI: 10.1016/j.molcel.2019.10.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 08/11/2019] [Accepted: 10/08/2019] [Indexed: 12/20/2022]
Abstract
R loops arising during transcription induce genomic instability, but how cells respond to the R loop-associated genomic stress is still poorly understood. Here, we show that cells harboring high levels of R loops rely on the ATR kinase for survival. In response to aberrant R loop accumulation, the ataxia telangiectasia and Rad3-related (ATR)-Chk1 pathway is activated by R loop-induced reversed replication forks. In contrast to the activation of ATR by replication inhibitors, R loop-induced ATR activation requires the MUS81 endonuclease. ATR protects the genome from R loops by suppressing transcription-replication collisions, promoting replication fork recovery, and enforcing a G2/M cell-cycle arrest. Furthermore, ATR prevents excessive cleavage of reversed forks by MUS81, revealing a MUS81-triggered and ATR-mediated feedback loop that fine-tunes MUS81 activity at replication forks. These results suggest that ATR is a key sensor and suppressor of R loop-induced genomic instability, uncovering a signaling circuitry that safeguards the genome against R loops.
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Affiliation(s)
- Dominick A Matos
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Hai Dang Nguyen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marie-Michelle Genois
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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46
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Deshar R, Yoo W, Cho EB, Kim S, Yoon JB. RNF8 mediates NONO degradation following UV-induced DNA damage to properly terminate ATR-CHK1 checkpoint signaling. Nucleic Acids Res 2019; 47:762-778. [PMID: 30445466 PMCID: PMC6344893 DOI: 10.1093/nar/gky1166] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 11/02/2018] [Indexed: 12/26/2022] Open
Abstract
RNF8 plays a critical role in DNA damage response (DDR) to initiate ubiquitination-dependent signaling. To better characterize the role of RNF8 in UV-induced DDR, we searched for novel substrates of RNF8 and identified NONO as one intriguing substrate. We found that: (i) RNF8 ubiquitinates NONO and (ii) UV radiation triggers NONO ubiquitination and its subsequent degradation. Depletion of RNF8 inhibited UV-induced degradation of NONO, suggesting that RNF8 targets NONO for degradation in response to UV damage. In addition, we found that 3 NONO lysine residues (positions 279, 290 and 295) are important for conferring its instability in UV-DDR. Depletion of RNF8 or expression of NONO with lysine to arginine substitutions at positions 279, 290 and 295 prolonged CHK1 phosphorylation over an extended period of time. Furthermore, expression of the stable mutant, but not wild-type NONO, induced a prolonged S phase following UV exposure. Stable cell lines expressing the stable NONO mutant showed increased UV sensitivity in a clonogenic survival assay. Since RNF8 recruitment to the UV-damaged sites is dependent on ATR, we propose that RNF8-mediated NONO degradation and subsequent inhibition of NONO-dependent chromatin loading of TOPBP1, a key activator of ATR, function as a negative feedback loop critical for turning off ATR-CHK1 checkpoint signaling in UV-DDR.
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Affiliation(s)
- Rakesh Deshar
- Department of Medical Lifesciences, The Catholic University of Korea, Seoul 137-701, Korea
| | - Wonjin Yoo
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Eun-Bee Cho
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Sungjoo Kim
- Department of Medical Lifesciences, The Catholic University of Korea, Seoul 137-701, Korea
| | - Jong-Bok Yoon
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, Seoul 120-749, Korea
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47
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García-Rodríguez N, Wong RP, Ulrich HD. The helicase Pif1 functions in the template switching pathway of DNA damage bypass. Nucleic Acids Res 2019; 46:8347-8356. [PMID: 30107417 PMCID: PMC6144865 DOI: 10.1093/nar/gky648] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/08/2018] [Indexed: 11/13/2022] Open
Abstract
Replication of damaged DNA is challenging because lesions in the replication template frequently interfere with an orderly progression of the replisome. In this situation, complete duplication of the genome is ensured by the action of DNA damage bypass pathways effecting either translesion synthesis by specialized, damage-tolerant DNA polymerases or a recombination-like mechanism called template switching (TS). Here we report that budding yeast Pif1, a helicase known to be involved in the resolution of complex DNA structures as well as the maturation of Okazaki fragments during replication, contributes to DNA damage bypass. We show that Pif1 expands regions of single-stranded DNA, so-called daughter-strand gaps, left behind the replication fork as a consequence of replisome re-priming. This function requires interaction with the replication clamp, proliferating cell nuclear antigen, facilitating its recruitment to damage sites, and complements the activity of an exonuclease, Exo1, in the processing of post-replicative daughter-strand gaps in preparation for TS. Our results thus reveal a novel function of a conserved DNA helicase that is known as a key player in genome maintenance.
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Affiliation(s)
| | - Ronald P Wong
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
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48
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Abstract
The ATR kinase is a master regulator of replication stress responses. Four new studies show that the protein ETAA1 is an important activator of ATR in human cells, providing insights into how the ATR pathway reacts to replication stress.
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Affiliation(s)
- Lee Zou
- MGH Cancer Center & Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
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49
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Kermi C, Aze A, Maiorano D. Preserving Genome Integrity During the Early Embryonic DNA Replication Cycles. Genes (Basel) 2019; 10:genes10050398. [PMID: 31137726 PMCID: PMC6563053 DOI: 10.3390/genes10050398] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
During the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed DNA damage response and, in certain animal species, a highly contracted S-phase. This raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. Recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate genetic and genomic alterations, most likely due to restricted cellular functions, in particular reduced DNA synthesis quality control. These findings may explain the low rate of successful development in mammals and the occurrence of diseases, such as abnormal developmental features and cancer. In this review, we will discuss recent findings in this field and put forward perspectives to further study this fascinating question.
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Affiliation(s)
- Chames Kermi
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
| | - Antoine Aze
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
| | - Domenico Maiorano
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
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50
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Abe T, Branzei D, Hirota K. DNA Damage Tolerance Mechanisms Revealed from the Analysis of Immunoglobulin V Gene Diversification in Avian DT40 Cells. Genes (Basel) 2018; 9:genes9120614. [PMID: 30544644 PMCID: PMC6316486 DOI: 10.3390/genes9120614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/26/2018] [Accepted: 11/30/2018] [Indexed: 01/19/2023] Open
Abstract
DNA replication is an essential biochemical reaction in dividing cells that frequently stalls at damaged sites. Homologous/homeologous recombination (HR)-mediated template switch and translesion DNA synthesis (TLS)-mediated bypass processes release arrested DNA replication forks. These mechanisms are pivotal for replication fork maintenance and play critical roles in DNA damage tolerance (DDT) and gap-filling. The avian DT40 B lymphocyte cell line provides an opportunity to examine HR-mediated template switch and TLS triggered by abasic sites by sequencing the constitutively diversifying immunoglobulin light-chain variable gene (IgV). During IgV diversification, activation-induced deaminase (AID) converts dC to dU, which in turn is excised by uracil DNA glycosylase and yields abasic sites within a defined window of around 500 base pairs. These abasic sites can induce gene conversion with a set of homeologous upstream pseudogenes via the HR-mediated template switch, resulting in templated mutagenesis, or can be bypassed directly by TLS, resulting in non-templated somatic hypermutation at dC/dG base pairs. In this review, we discuss recent works unveiling IgV diversification mechanisms in avian DT40 cells, which shed light on DDT mode usage in vertebrate cells and tolerance of abasic sites.
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Affiliation(s)
- Takuya Abe
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
| | - Dana Branzei
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100 Pavia, Italy.
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
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