1
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Gál Z, Boukoura S, Oxe KC, Badawi S, Nieto B, Korsholm LM, Geisler SB, Dulina E, Rasmussen AV, Dahl C, Lv W, Xu H, Pan X, Arampatzis S, Stratou DE, Galanos P, Lin L, Guldberg P, Bartek J, Luo Y, Larsen DH. Hyper-recombination in ribosomal DNA is driven by long-range resection-independent RAD51 accumulation. Nat Commun 2024; 15:7797. [PMID: 39242676 PMCID: PMC11379943 DOI: 10.1038/s41467-024-52189-6] [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: 09/29/2023] [Accepted: 08/28/2024] [Indexed: 09/09/2024] Open
Abstract
Ribosomal DNA (rDNA) encodes the ribosomal RNA genes and represents an intrinsically unstable genomic region. However, the underlying mechanisms and implications for genome integrity remain elusive. Here, we use Bloom syndrome (BS), a rare genetic disease characterized by DNA repair defects and hyper-unstable rDNA, as a model to investigate the mechanisms leading to rDNA instability. We find that in Bloom helicase (BLM) proficient cells, the homologous recombination (HR) pathway in rDNA resembles that in nuclear chromatin; it is initiated by resection, replication protein A (RPA) loading and BRCA2-dependent RAD51 filament formation. However, BLM deficiency compromises RPA-loading and BRCA1/2 recruitment to rDNA, but not RAD51 accumulation. RAD51 accumulates at rDNA despite depletion of long-range resection nucleases and rDNA damage results in micronuclei when BLM is absent. In summary, our findings indicate that rDNA is permissive to RAD51 accumulation in the absence of BLM, leading to micronucleation and potentially global genomic instability.
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Affiliation(s)
- Zita Gál
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Stavroula Boukoura
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | - Kezia Catharina Oxe
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | - Sara Badawi
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | - Blanca Nieto
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | - Lea Milling Korsholm
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Genome Integrity Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Ekaterina Dulina
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Genome Integrity Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | | | - Christina Dahl
- Molecular Diagnostics, Danish Cancer Institute, 2100, Copenhagen, Denmark
| | - Wei Lv
- Department of Biomedicine, Aarhus University, Aarhus, 8000, Denmark
| | - Huixin Xu
- Department of Biomedicine, Aarhus University, Aarhus, 8000, Denmark
| | - Xiaoguang Pan
- Department of Biology, University of Copenhagen, Copenhagen N, DK-2200, Denmark
| | | | | | - Panagiotis Galanos
- Genome Integrity Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, Aarhus, 8000, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, 8200, Denmark
| | - Per Guldberg
- Molecular Diagnostics, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, 5000, Denmark
| | - Jiri Bartek
- Genome Integrity Group, Danish Cancer Institute, 2100, Copenhagen, Denmark
- Karolinska Institutet, Department of Medical Biochemistry and Biophysics, Division of Genome Biology, Science for Life Laboratory, Stockholm, Sweden
| | - Yonglun Luo
- Department of Biomedicine, Aarhus University, Aarhus, 8000, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, 8200, Denmark
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Dorthe H Larsen
- Nucleolar Stress and Disease Group, Danish Cancer Institute, 2100, Copenhagen, Denmark.
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2
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Matsuzaki K, Shinohara A, Shinohara M. Human AAA+ ATPase FIGNL1 suppresses RAD51-mediated ultra-fine bridge formation. Nucleic Acids Res 2024; 52:5774-5791. [PMID: 38597669 PMCID: PMC11162793 DOI: 10.1093/nar/gkae263] [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: 08/31/2023] [Revised: 03/09/2024] [Accepted: 03/29/2024] [Indexed: 04/11/2024] Open
Abstract
RAD51 filament is crucial for the homology-dependent repair of DNA double-strand breaks and stalled DNA replication fork protection. Positive and negative regulators control RAD51 filament assembly and disassembly. RAD51 is vital for genome integrity but excessive accumulation of RAD51 on chromatin causes genome instability and growth defects. However, the detailed mechanism underlying RAD51 disassembly by negative regulators and the physiological consequence of abnormal RAD51 persistence remain largely unknown. Here, we report the role of the human AAA+ ATPase FIGNL1 in suppressing a novel type of RAD51-mediated genome instability. FIGNL1 knockout human cells were defective in RAD51 dissociation after replication fork restart and accumulated ultra-fine chromosome bridges (UFBs), whose formation depends on RAD51 rather than replication fork stalling. FIGNL1 suppresses homologous recombination intermediate-like UFBs generated between sister chromatids at genomic loci with repeated sequences such as telomeres and centromeres. These data suggest that RAD51 persistence per se induces the formation of unresolved linkage between sister chromatids resulting in catastrophic genome instability. FIGNL1 facilitates post-replicative disassembly of RAD51 filament to suppress abnormal recombination intermediates and UFBs. These findings implicate FIGNL1 as a key factor required for active RAD51 removal after processing of stalled replication forks, which is essential to maintain genome stability.
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Affiliation(s)
- Kenichiro Matsuzaki
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara City, Nara 631-8505, Japan
| | - Akira Shinohara
- Laboratory of Genome and Chromosome Functions, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Miki Shinohara
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara City, Nara 631-8505, Japan
- Agricultural Technology and Innovation Research Institute, Kindai University, Nara City, Nara 631-8505, Japan
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3
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Jiang H, Zhang T, Kaur H, Shi T, Krishnan A, Kwon Y, Sung P, Greenberg RA. BLM helicase unwinds lagging strand substrates to assemble the ALT telomere damage response. Mol Cell 2024; 84:1684-1698.e9. [PMID: 38593805 PMCID: PMC11069441 DOI: 10.1016/j.molcel.2024.03.011] [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: 09/18/2023] [Revised: 02/12/2024] [Accepted: 03/14/2024] [Indexed: 04/11/2024]
Abstract
The Bloom syndrome (BLM) helicase is critical for alternative lengthening of telomeres (ALT), a homology-directed repair (HDR)-mediated telomere maintenance mechanism that is prevalent in cancers of mesenchymal origin. The DNA substrates that BLM engages to direct telomere recombination during ALT remain unknown. Here, we determine that BLM helicase acts on lagging strand telomere intermediates that occur specifically in ALT-positive cells to assemble a replication-associated DNA damage response. Loss of ATRX was permissive for BLM localization to ALT telomeres in S and G2, commensurate with the appearance of telomere C-strand-specific single-stranded DNA (ssDNA). DNA2 nuclease deficiency increased 5'-flap formation in a BLM-dependent manner, while telomere C-strand, but not G-strand, nicks promoted ALT. These findings define the seminal events in the ALT DNA damage response, linking aberrant telomeric lagging strand DNA replication with a BLM-directed HDR mechanism that sustains telomere length in a subset of human cancers.
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Affiliation(s)
- Haoyang Jiang
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Tianpeng Zhang
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Hardeep Kaur
- Department of Biochemistry and Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Tao Shi
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Aravind Krishnan
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology and Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Roger A Greenberg
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
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4
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Fan J, Dhingra N, Yang T, Yang V, Zhao X. Srs2 binding to PCNA and its sumoylation contribute to RPA antagonism during the DNA damage response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587206. [PMID: 38586001 PMCID: PMC10996639 DOI: 10.1101/2024.03.28.587206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Activation of the DNA damage checkpoint upon genotoxin treatment induces a multitude of cellular changes, such as cell cycle arrest, to cope with genome stress. After prolonged genotoxin treatment, the checkpoint can be downregulated to allow cell cycle and growth resumption. In yeast, downregulation of the DNA damage checkpoint requires the Srs2 DNA helicase, which removes the ssDNA binding complex RPA and the associated Mec1 checkpoint kinase from DNA, thus dampening Mec1 activation. However, it is unclear whether the 'anti-checkpoint' role of Srs2 is temporally and spatially regulated to both allow timely checkpoint termination and to prevent superfluous RPA removal. Here we address this question by examining regulatory elements of Srs2, including its phosphorylation, sumoylation, and protein-interaction sites. Our genetic analyses and checkpoint level assessment suggest that the RPA countering role of Srs2 is promoted by Srs2 binding to PCNA, which is known to recruit Srs2 to subsets of ssDNA regions. RPA antagonism is further fostered by Srs2 sumoylation, which we found depends on the Srs2-PCNA interaction. Srs2 sumoylation is additionally reliant on Mec1 and peaks after Mec1 activity reaches maximal levels. Collectively, our data provide evidence for a two-step model wherein checkpoint downregulation is facilitated by PCNA-mediated Srs2 recruitment to ssDNA-RPA filaments and the subsequent Srs2 sumoylation stimulated upon Mec1 hyperactivation. We propose that this mechanism allows Mec1 hyperactivation to trigger checkpoint recovery.
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Affiliation(s)
- Jiayi Fan
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Nalini Dhingra
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Tammy Yang
- City University of New York Hunter College, New York, NY 10065
| | - Vicki Yang
- City University of New York Hunter College, New York, NY 10065
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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5
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Kotenko O, Makovets S. The functional significance of the RPA- and PCNA-dependent recruitment of Pif1 to DNA. EMBO Rep 2024; 25:1734-1751. [PMID: 38480846 PMCID: PMC11014909 DOI: 10.1038/s44319-024-00114-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 02/10/2024] [Accepted: 02/26/2024] [Indexed: 04/14/2024] Open
Abstract
Pif1 family helicases are multifunctional proteins conserved in eukaryotes, from yeast to humans. They are important for the genome maintenance in both nuclei and mitochondria, where they have been implicated in Okazaki fragment processing, replication fork progression and termination, telomerase regulation and DNA repair. While the Pif1 helicase activity is readily detectable on naked nucleic acids in vitro, the in vivo functions rely on recruitment to DNA. We identify the single-stranded DNA binding protein complex RPA as the major recruiter of Pif1 in budding yeast, in addition to the previously reported Pif1-PCNA interaction. The two modes of the Pif1 recruitment act independently during telomerase inhibition, as the mutations in the Pif1 motifs disrupting either of the recruitment pathways act additively. In contrast, both recruitment mechanisms are essential for the replication-related roles of Pif1 at conventional forks and during the repair by break-induced replication. We propose a molecular model where RPA and PCNA provide a double anchoring of Pif1 at replication forks, which is essential for the Pif1 functions related to the fork movement.
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Affiliation(s)
- Oleksii Kotenko
- Institute of Cell Biology, University of Edinburgh, King's Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK
| | - Svetlana Makovets
- Institute of Cell Biology, University of Edinburgh, King's Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK.
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6
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Tsukada K, Jones SE, Bannister J, Durin MA, Vendrell I, Fawkes M, Fischer R, Kessler BM, Chapman JR, Blackford AN. BLM and BRCA1-BARD1 coordinate complementary mechanisms of joint DNA molecule resolution. Mol Cell 2024; 84:640-658.e10. [PMID: 38266639 DOI: 10.1016/j.molcel.2023.12.040] [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: 03/18/2023] [Revised: 10/10/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex. We show that this is due to a previously overlooked role for BARD1 in recruiting SLX4 to resolve DNA intermediates left unprocessed by BLM in the preceding interphase. Consequently, cells with defective BLM and BRCA1-BARD1 accumulate catastrophic levels of chromosome breakage and micronucleation, leading to cell death. Thus, we reveal mechanistic insights into SLX4 recruitment to DNA lesions, with potential clinical implications for treating BRCA1-deficient tumors.
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Affiliation(s)
- Kaima Tsukada
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Samuel E Jones
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Julius Bannister
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Mary-Anne Durin
- MRC Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Iolanda Vendrell
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Matthew Fawkes
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Roman Fischer
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Benedikt M Kessler
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - J Ross Chapman
- MRC Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Andrew N Blackford
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
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7
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Ito M, Fujita Y, Shinohara A. Positive and negative regulators of RAD51/DMC1 in homologous recombination and DNA replication. DNA Repair (Amst) 2024; 134:103613. [PMID: 38142595 DOI: 10.1016/j.dnarep.2023.103613] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023]
Abstract
RAD51 recombinase plays a central role in homologous recombination (HR) by forming a nucleoprotein filament on single-stranded DNA (ssDNA) to catalyze homology search and strand exchange between the ssDNA and a homologous double-stranded DNA (dsDNA). The catalytic activity of RAD51 assembled on ssDNA is critical for the DNA-homology-mediated repair of DNA double-strand breaks in somatic and meiotic cells and restarting stalled replication forks during DNA replication. The RAD51-ssDNA complex also plays a structural role in protecting the regressed/reversed replication fork. Two types of regulators control RAD51 filament formation, stability, and dynamics, namely positive regulators, including mediators, and negative regulators, so-called remodelers. The appropriate balance of action by the two regulators assures genome stability. This review describes the roles of positive and negative RAD51 regulators in HR and DNA replication and its meiosis-specific homolog DMC1 in meiotic recombination. We also provide future study directions for a comprehensive understanding of RAD51/DMC1-mediated regulation in maintaining and inheriting genome integrity.
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Affiliation(s)
- Masaru Ito
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Yurika Fujita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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8
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Xu MJ, Jordan PW. SMC5/6 Promotes Replication Fork Stability via Negative Regulation of the COP9 Signalosome. Int J Mol Sci 2024; 25:952. [PMID: 38256025 PMCID: PMC10815603 DOI: 10.3390/ijms25020952] [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: 12/04/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
It is widely accepted that DNA replication fork stalling is a common occurrence during cell proliferation, but there are robust mechanisms to alleviate this and ensure DNA replication is completed prior to chromosome segregation. The SMC5/6 complex has consistently been implicated in the maintenance of replication fork integrity. However, the essential role of the SMC5/6 complex during DNA replication in mammalian cells has not been elucidated. In this study, we investigate the molecular consequences of SMC5/6 loss at the replication fork in mouse embryonic stem cells (mESCs), employing the auxin-inducible degron (AID) system to deplete SMC5 acutely and reversibly in the defined cellular contexts of replication fork stall and restart. In SMC5-depleted cells, we identify a defect in the restart of stalled replication forks, underpinned by excess MRE11-mediated fork resection and a perturbed localization of fork protection factors to the stalled fork. Previously, we demonstrated a physical and functional interaction of SMC5/6 with the COP9 signalosome (CSN), a cullin deneddylase that enzymatically regulates cullin ring ligase (CRL) activity. Employing a combination of DNA fiber techniques, the AID system, small-molecule inhibition assays, and immunofluorescence microscopy analyses, we show that SMC5/6 promotes the localization of fork protection factors to stalled replication forks by negatively modulating the COP9 signalosome (CSN). We propose that the SMC5/6-mediated modulation of the CSN ensures that CRL activity and their roles in DNA replication fork stabilization are maintained to allow for efficient replication fork restart when a replication fork stall is alleviated.
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Affiliation(s)
- Michelle J. Xu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Philip W. Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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9
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Nasheuer HP, Meaney AM, Hulshoff T, Thiele I, Onwubiko NO. Replication Protein A, the Main Eukaryotic Single-Stranded DNA Binding Protein, a Focal Point in Cellular DNA Metabolism. Int J Mol Sci 2024; 25:588. [PMID: 38203759 PMCID: PMC10779431 DOI: 10.3390/ijms25010588] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024] Open
Abstract
Replication protein A (RPA) is a heterotrimeric protein complex and the main single-stranded DNA (ssDNA)-binding protein in eukaryotes. RPA has key functions in most of the DNA-associated metabolic pathways and DNA damage signalling. Its high affinity for ssDNA helps to stabilise ssDNA structures and protect the DNA sequence from nuclease attacks. RPA consists of multiple DNA-binding domains which are oligonucleotide/oligosaccharide-binding (OB)-folds that are responsible for DNA binding and interactions with proteins. These RPA-ssDNA and RPA-protein interactions are crucial for DNA replication, DNA repair, DNA damage signalling, and the conservation of the genetic information of cells. Proteins such as ATR use RPA to locate to regions of DNA damage for DNA damage signalling. The recruitment of nucleases and DNA exchange factors to sites of double-strand breaks are also an important RPA function to ensure effective DNA recombination to correct these DNA lesions. Due to its high affinity to ssDNA, RPA's removal from ssDNA is of central importance to allow these metabolic pathways to proceed, and processes to exchange RPA against downstream factors are established in all eukaryotes. These faceted and multi-layered functions of RPA as well as its role in a variety of human diseases will be discussed.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Anna Marie Meaney
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Timothy Hulshoff
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Ines Thiele
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Nichodemus O. Onwubiko
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
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10
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Saha LK, Pommier Y. TOP3A coupling with replication forks and repair of TOP3A cleavage complexes. Cell Cycle 2024; 23:115-130. [PMID: 38341866 PMCID: PMC11037291 DOI: 10.1080/15384101.2024.2314440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/08/2024] [Indexed: 02/13/2024] Open
Abstract
Humans have two Type IA topoisomerases, topoisomerase IIIα (TOP3A) and topoisomerase IIIβ (TOP3B). In this review, we focus on the role of human TOP3A in DNA replication and highlight the recent progress made in understanding TOP3A in the context of replication. Like other topoisomerases, TOP3A acts by a reversible mechanism of cleavage and rejoining of DNA strands allowing changes in DNA topology. By cleaving and resealing single-stranded DNA, it generates TOP3A-linked single-strand breaks as TOP3A cleavage complexes (TOP3Accs) with a TOP3A molecule covalently bound to the 5´-end of the break. TOP3A is critical for both mitochondrial and for nuclear DNA replication. Here, we discuss the formation and repair of irreversible TOP3Accs, as their presence compromises genome integrity as they form TOP3A DNA-protein crosslinks (TOP3A-DPCs) associated with DNA breaks. We discuss the redundant pathways that repair TOP3A-DPCs, and how their defects are a source of DNA damage leading to neurological diseases and mitochondrial disorders.
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Affiliation(s)
- Liton Kumar Saha
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
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11
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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12
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Zhang W, Yu X, Bao L, He T, Pan W, Li P, Liu J, Liu X, Yang L, Liu J. Bisbenzylisoquinoline alkaloid fangchinoline derivative HY-2 inhibits breast cancer cells by suppressing BLM DNA helicase. Biomed Pharmacother 2023; 169:115908. [PMID: 37988849 DOI: 10.1016/j.biopha.2023.115908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/23/2023] Open
Abstract
The high expression of BLM (Bloom syndrome) DNA helicase in tumors involves its strong association with cell expansion. Bisbenzylisoquinoline alkaloids own an antitumor property and have developed as candidates for anticancer drugs. This paper aimed to study the antitumor effect of fangchinoline derivative HY-2 by targeting BLM642-1290 DNA helicase, and then explore its inhibitory mechanism on proliferation of MDA-MB-435 breast cancer cells. We confirmed that the mRNA and protein levels of BLM DNA helicase in breast cancer were higher than those in normal tissues. HY-2 could inhibit the DNA binding, ATPase and DNA unwinding of BLM642-1290 DNA helicase with enzymatic assay. HY-2 could also inhibit the DNA unwinding of DNA helicase in cells. In addition, HY-2 showed an inhibiting the MDA-MB-435, MDA-MB-231, MDA-MB-436 breast cancer cells expansion. The mRNA and protein levels of BLM DNA helicase in MDA-MB-435 cells increased after HY-2 treatment, which might contribute to HY-2 inhibiting the DNA binding, ATPase and DNA unwinding of BLM DNA helicase. The mechanism of HY-2 inhibition on BLM DNA helicase was further confirmed with the effect of HY-2 on the ultraviolet spectrogram of BLM642-1290 DNA helicase and Molecular dynamics simulation of the interacting between HY-2 and BLM640-1291 DNA helicase. Our study provided some valuable clues for the exploration of HY-2 in the living body and developing it as an anticancer drug.
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Affiliation(s)
- Wangming Zhang
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China
| | - Xiaojing Yu
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China
| | - Linchun Bao
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China; Clinical Laboratory, People's Hospital of Qianxinan Buyi and Miao Minority Autonomous Prefecture, Guizhou, Xingyi 562400, People's Republic of China
| | - Tianhui He
- Dejiang County Hospital of Traditional Chinese Medicine, Dejiang County South Avenue, Dejiang 565299, People's Republic of China
| | - Weidong Pan
- State Key Laboratory of Functions and Applications of Medicinal Plants (Guizhou Medical University), Guizhou Science City, Guiyang 550014, People's Republic of China
| | - Pinhao Li
- Department of Pathology, Affiliated Hospital of Guizhou Medical University, 28 Guiyi Street, Guiyang 550001, People's Republic of China
| | - Jinhe Liu
- Tissue Engineering and Stem Cell Research Center, Guizhou Medical University, Guiyang 550004, People's Republic of China
| | - Xiaohua Liu
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China
| | - Liuqi Yang
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China
| | - Jielin Liu
- Department of Immunology, Basic Medical College, Guizhou Medical University, 9 Beijing Road, Guiyang 550025, People's Republic of China; State Key Laboratory of Functions and Applications of Medicinal Plants (Guizhou Medical University), Guizhou Science City, Guiyang 550014, People's Republic of China.
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13
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Fragkos M, Choleza M, Papadopoulou P. The Role of γH2AX in Replication Stress-induced Carcinogenesis: Possible Links and Recent Developments. CANCER DIAGNOSIS & PROGNOSIS 2023; 3:639-648. [PMID: 37927801 PMCID: PMC10619570 DOI: 10.21873/cdp.10266] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/11/2023] [Indexed: 11/07/2023]
Abstract
Cancer is a condition characterized by genomic instability and gross chromosomal aberrations. The inability of the cell to timely and efficiently complete its replication cycle before entering mitosis is one of the most common causes of DNA damage and carcinogenesis. Phosphorylation of histone 2AX (H2AX) on S139 (γH2AX) is an indispensable step in the response to DNA damage, as it is required for the assembly of repair factors at the sites of damage. γH2AX is also a marker of DNA replication stress, mainly due to fork collapse that often follows prolonged replication stalling or repair of arrested forks, which involves the generation of DNA breaks. Although the role of γH2AX in the repair of DNA breaks has been well defined, the function of γH2AX in replicative stress remains unclear. In this review, we present the recent advances in the field of replication stress, and highlight a novel function for γH2AX that is independent of its role in the response to DNA damage. We discuss studies that support a role for γΗ2ΑΧ early in the response to replicative stress, which does not involve the repair of DNA breaks. We also highlight recent data proposing that γH2AX acts as a chromatin remodeling component, implicated in the efficient resolution of stalled replication forks. Understanding the mechanism by which γH2AX enables cellular recovery after replication stress will allow identification of novel cancer biomarkers, as well as new targets for cancer therapies.
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Affiliation(s)
- Michalis Fragkos
- Department of Science and Mathematics, Deree-The American College of Greece, Athens, Greece
| | - Maria Choleza
- Department of Science and Mathematics, Deree-The American College of Greece, Athens, Greece
| | - Paraskevi Papadopoulou
- Department of Science and Mathematics, Deree-The American College of Greece, Athens, Greece
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14
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Pike AM, Friend CM, Bell SP. Distinct RPA functions promote eukaryotic DNA replication initiation and elongation. Nucleic Acids Res 2023; 51:10506-10518. [PMID: 37739410 PMCID: PMC10602884 DOI: 10.1093/nar/gkad765] [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: 11/17/2022] [Revised: 08/14/2023] [Accepted: 09/10/2023] [Indexed: 09/24/2023] Open
Abstract
Replication protein A (RPA) binds single-stranded DNA (ssDNA) and serves critical functions in eukaryotic DNA replication, the DNA damage response, and DNA repair. During DNA replication, RPA is required for extended origin DNA unwinding and DNA synthesis. To determine the requirements for RPA during these processes, we tested ssDNA-binding proteins (SSBs) from different domains of life in reconstituted Saccharomyces cerevisiae origin unwinding and DNA replication reactions. Interestingly, Escherichia coli SSB, but not T4 bacteriophage Gp32, fully substitutes for RPA in promoting origin DNA unwinding. Using RPA mutants, we demonstrated that specific ssDNA-binding properties of RPA are required for origin unwinding but that its protein-interaction domains are dispensable. In contrast, we found that each of these auxiliary RPA domains have distinct functions at the eukaryotic replication fork. The Rfa1 OB-F domain negatively regulates lagging-strand synthesis, while the Rfa2 winged-helix domain stimulates nascent strand initiation. Together, our findings reveal a requirement for specific modes of ssDNA binding in the transition to extensive origin DNA unwinding and identify RPA domains that differentially impact replication fork function.
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Affiliation(s)
- Alexandra M Pike
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Caitlin M Friend
- Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Stephen P Bell
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
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15
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Danino YM, Molitor L, Rosenbaum-Cohen T, Kaiser S, Cohen Y, Porat Z, Marmor-Kollet H, Katina C, Savidor A, Rotkopf R, Ben-Isaac E, Golani O, Levin Y, Monchaud D, Hickson I, Hornstein E. BLM helicase protein negatively regulates stress granule formation through unwinding RNA G-quadruplex structures. Nucleic Acids Res 2023; 51:9369-9384. [PMID: 37503837 PMCID: PMC10516661 DOI: 10.1093/nar/gkad613] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 07/29/2023] Open
Abstract
Bloom's syndrome (BLM) protein is a known nuclear helicase that is able to unwind DNA secondary structures such as G-quadruplexes (G4s). However, its role in the regulation of cytoplasmic processes that involve RNA G-quadruplexes (rG4s) has not been previously studied. Here, we demonstrate that BLM is recruited to stress granules (SGs), which are cytoplasmic biomolecular condensates composed of RNAs and RNA-binding proteins. BLM is enriched in SGs upon different stress conditions and in an rG4-dependent manner. Also, we show that BLM unwinds rG4s and acts as a negative regulator of SG formation. Altogether, our data expand the cellular activity of BLM and shed light on the function that helicases play in the dynamics of biomolecular condensates.
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Affiliation(s)
- Yehuda M Danino
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Lena Molitor
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tamar Rosenbaum-Cohen
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Brain science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sebastian Kaiser
- Center for Chromosome Stability, Dept. of Cellular and Molecular Medicine, Panum Institute, Copenhagen Univ, 2200 København N., Denmark
| | - Yahel Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ziv Porat
- Flow Cytometry Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hagai Marmor-Kollet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
- 1E therapeutics, Rehovot, Israel
| | - Corine Katina
- de Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Alon Savidor
- de Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ron Rotkopf
- Bioinformatics Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eyal Ben-Isaac
- MICC Cell Observatory Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ofra Golani
- MICC Cell Observatory Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yishai Levin
- de Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - David Monchaud
- Institut de Chimie Moleculaire, ICMUB CNRS UMR 6302, uB Dijon, France
| | - Ian D Hickson
- Center for Chromosome Stability, Dept. of Cellular and Molecular Medicine, Panum Institute, Copenhagen Univ, 2200 København N., Denmark
| | - Eran Hornstein
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
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16
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Wu Y, Fu W, Zang N, Zhou C. Structural characterization of human RPA70N association with DNA damage response proteins. eLife 2023; 12:e81639. [PMID: 37668474 PMCID: PMC10479964 DOI: 10.7554/elife.81639] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/09/2023] [Indexed: 09/06/2023] Open
Abstract
The heterotrimeric Replication protein A (RPA) is the ubiquitous eukaryotic single-stranded DNA (ssDNA) binding protein and participates in nearly all aspects of DNA metabolism, especially DNA damage response. The N-terminal OB domain of the RPA70 subunit (RPA70N) is a major protein-protein interaction element for RPA and binds to more than 20 partner proteins. Previous crystallography studies of RPA70N with p53, DNA2 and PrimPol fragments revealed that RPA70N binds to amphipathic peptides that mimic ssDNA. NMR chemical-shift studies also provided valuable information on the interaction of RPA70N residues with target sequences. However, it is still unclear how RPA70N recognizes and distinguishes such a diverse group of target proteins. Here, we present high-resolution crystal structures of RPA70N in complex with peptides from eight DNA damage response proteins. The structures show that, in addition to the ssDNA mimicry mode of interaction, RPA70N employs multiple ways to bind its partners. Our results advance the mechanistic understanding of RPA70N-mediated recruitment of DNA damage response proteins.
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Affiliation(s)
- Yeyao Wu
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Wangmi Fu
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Ning Zang
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Chun Zhou
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
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17
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Hertz EPT, Vega IAD, Kruse T, Wang Y, Hendriks IA, Bizard AH, Eugui-Anta A, Hay RT, Nielsen ML, Nilsson J, Hickson ID, Mailand N. The SUMO-NIP45 pathway processes toxic DNA catenanes to prevent mitotic failure. Nat Struct Mol Biol 2023; 30:1303-1313. [PMID: 37474739 PMCID: PMC10497417 DOI: 10.1038/s41594-023-01045-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 06/26/2023] [Indexed: 07/22/2023]
Abstract
SUMOylation regulates numerous cellular processes, but what represents the essential functions of this protein modification remains unclear. To address this, we performed genome-scale CRISPR-Cas9-based screens, revealing that the BLM-TOP3A-RMI1-RMI2 (BTRR)-PICH pathway, which resolves ultrafine anaphase DNA bridges (UFBs) arising from catenated DNA structures, and the poorly characterized protein NIP45/NFATC2IP become indispensable for cell proliferation when SUMOylation is inhibited. We demonstrate that NIP45 and SUMOylation orchestrate an interphase pathway for converting DNA catenanes into double-strand breaks (DSBs) that activate the G2 DNA-damage checkpoint, thereby preventing cytokinesis failure and binucleation when BTRR-PICH-dependent UFB resolution is defective. NIP45 mediates this new TOP2-independent DNA catenane resolution process via its SUMO-like domains, promoting SUMOylation of specific factors including the SLX4 multi-nuclease complex, which contributes to catenane conversion into DSBs. Our findings establish that SUMOylation exerts its essential role in cell proliferation by enabling resolution of toxic DNA catenanes via nonepistatic NIP45- and BTRR-PICH-dependent pathways to prevent mitotic failure.
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Affiliation(s)
- Emil P T Hertz
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.
| | - Ignacio Alonso-de Vega
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Kruse
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Yiqing Wang
- Center for Chromosome Stability, University of Copenhagen, Copenhagen, Denmark
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Ivo A Hendriks
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Anna H Bizard
- Center for Chromosome Stability, University of Copenhagen, Copenhagen, Denmark
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Ania Eugui-Anta
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Ronald T Hay
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Michael L Nielsen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Nilsson
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability, University of Copenhagen, Copenhagen, Denmark
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Niels Mailand
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.
- Center for Chromosome Stability, University of Copenhagen, Copenhagen, Denmark.
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18
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Noto A, Valenzisi P, Fratini F, Kulikowicz T, Sommers JA, Di Feo F, Palermo V, Semproni M, Crescenzi M, Brosh RM, Franchitto A, Pichierri P. PHOSPHORYLATION-DEPENDENT ASSOCIATION OF WRN WITH RPA IS REQUIRED FOR RECOVERY OF REPLICATION FORKS STALLED AT SECONDARY DNA STRUCTURES. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552428. [PMID: 37609214 PMCID: PMC10441285 DOI: 10.1101/2023.08.08.552428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The WRN protein mutated in the hereditary premature aging disorder Werner syndrome plays a vital role in handling, processing, and restoring perturbed replication forks. One of its most abundant partners, Replication Protein A (RPA), has been shown to robustly enhance WRN helicase activity in specific cases when tested in vitro. However, the significance of RPA-binding to WRN at replication forks in vivo has remained largely unexplored. In this study, we have identified several conserved phosphorylation sites in the acidic domain of WRN that are targeted by Casein Kinase 2 (CK2). Surprisingly, these phosphorylation sites are essential for the interaction between WRN and RPA, both in vitro and in human cells. By characterizing a CK2-unphosphorylatable WRN mutant that lacks the ability to bind RPA, we have determined that the WRN-RPA complex plays a critical role in fork recovery after replication stress whereas the WRN-RPA interaction is not necessary for the processing of replication forks or preventing DNA damage when forks stall or collapse. When WRN fails to bind RPA, fork recovery is impaired, leading to the accumulation of single-stranded DNA gaps in the parental strands, which are further enlarged by the structure-specific nuclease MRE11. Notably, RPA-binding by WRN and its helicase activity are crucial for countering the persistence of G4 structures after fork stalling. Therefore, our findings reveal for the first time a novel role for the WRN-RPA interaction to facilitate fork restart, thereby minimizing G4 accumulation at single-stranded DNA gaps and suppressing accumulation of unreplicated regions that may lead to MUS81-dependent double-strand breaks requiring efficient repair by RAD51 to prevent excessive DNA damage.
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Affiliation(s)
- Alessandro Noto
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Pasquale Valenzisi
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Federica Fratini
- Core Facilities Technical-Scientific Service, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Tomasz Kulikowicz
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Joshua A. Sommers
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Flavia Di Feo
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Valentina Palermo
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Maurizio Semproni
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Marco Crescenzi
- Core Facilities Technical-Scientific Service, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Robert M. Brosh
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, 251 Bayview Blvd, Baltimore, MD 21224 (USA)
| | - Annapaola Franchitto
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
| | - Pietro Pichierri
- Mechanisms, Biomarkers and Models Section – Genome Stability Group, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299 – 00161 Rome (Italy)
- Istituto Nazionale di Biostrutture e Biosistemi, Viale delle Medaglie d’Oro 305 – 00134 Rome (Italy)
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19
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Roshan P, Kuppa S, Mattice JR, Kaushik V, Chadda R, Pokhrel N, Tumala BR, Biswas A, Bothner B, Antony E, Origanti S. An Aurora B-RPA signaling axis secures chromosome segregation fidelity. Nat Commun 2023; 14:3008. [PMID: 37230964 PMCID: PMC10212944 DOI: 10.1038/s41467-023-38711-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 05/09/2023] [Indexed: 05/27/2023] Open
Abstract
Errors in chromosome segregation underlie genomic instability associated with cancers. Resolution of replication and recombination intermediates and protection of vulnerable single-stranded DNA (ssDNA) intermediates during mitotic progression requires the ssDNA binding protein Replication Protein A (RPA). However, the mechanisms that regulate RPA specifically during unperturbed mitotic progression are poorly resolved. RPA is a heterotrimer composed of RPA70, RPA32 and RPA14 subunits and is predominantly regulated through hyperphosphorylation of RPA32 in response to DNA damage. Here, we have uncovered a mitosis-specific regulation of RPA by Aurora B kinase. Aurora B phosphorylates Ser-384 in the DNA binding domain B of the large RPA70 subunit and highlights a mode of regulation distinct from RPA32. Disruption of Ser-384 phosphorylation in RPA70 leads to defects in chromosome segregation with loss of viability and a feedback modulation of Aurora B activity. Phosphorylation at Ser-384 remodels the protein interaction domains of RPA. Furthermore, phosphorylation impairs RPA binding to DSS1 that likely suppresses homologous recombination during mitosis by preventing recruitment of DSS1-BRCA2 to exposed ssDNA. We showcase a critical Aurora B-RPA signaling axis in mitosis that is essential for maintaining genomic integrity.
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Affiliation(s)
- Poonam Roshan
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Jenna R Mattice
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53217, USA
| | - Brunda R Tumala
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Aparna Biswas
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Brian Bothner
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA.
| | - Sofia Origanti
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA.
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20
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Saha LK, Saha S, Yang X, Huang SYN, Sun Y, Jo U, Pommier Y. Replication-associated formation and repair of human topoisomerase IIIα cleavage complexes. Nat Commun 2023; 14:1925. [PMID: 37024461 PMCID: PMC10079683 DOI: 10.1038/s41467-023-37498-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 03/08/2023] [Indexed: 04/08/2023] Open
Abstract
Topoisomerase IIIα (TOP3A) belongs to the conserved Type IA family of DNA topoisomerases. Here we report that human TOP3A is associated with DNA replication forks and that a "self-trapping" TOP3A mutant (TOP3A-R364W) generates cellular TOP3A DNA cleavage complexes (TOP3Accs). We show that trapped TOP3Accs that interfere with replication, induce DNA damage and genome instability. To elucidate how TOP3Accs are repaired, we explored the role of Spartan (SPRTN), the metalloprotease associated with DNA replication, which digests proteins forming DNA-protein crosslinks (DPCs). We find that SPRTN-deficient cells show elevated TOP3Accs, whereas overexpression of SPRTN lowers cellular TOP3Accs. SPRTN is deubiquitinated and epistatic with TDP2 in response to TOP3Accs. In addition, we found that MRE11 can excise TOP3Accs, and that cell cycle determines the preference for the SPRTN-TDP2 vs. the ATM-MRE11 pathways, in S vs. G2, respectively. Our study highlights the prevalence of TOP3Accs repair mechanisms to ensure normal DNA replication.
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Affiliation(s)
- Liton Kumar Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Sourav Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Xi Yang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Yilun Sun
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Ukhyun Jo
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Yves Pommier
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
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21
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Datta A, Sommers JA, Jhujh SS, Harel T, Stewart GS, Brosh RM. Discovery of a new hereditary RECQ helicase disorder RECON syndrome positions the replication stress response and genome homeostasis as centrally important processes in aging and age-related disease. Ageing Res Rev 2023; 86:101887. [PMID: 36805074 PMCID: PMC10018417 DOI: 10.1016/j.arr.2023.101887] [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: 12/23/2022] [Revised: 02/02/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023]
Abstract
Characterizing the molecular deficiencies underlying human aging has been a formidable challenge as it is clear that a complex myriad of factors including genetic mutations, environmental influences, and lifestyle choices influence the deterioration responsible for human pathologies. In addition, the common denominators of human aging, exemplified by the newly updated hallmarks of aging (López-Otín et al., 2023), suggest multiple avenues and layers of crosstalk between pathways important for genome and cellular homeostasis, both of which are major determinants of both good health and lifespan. In this regard, we postulate that hereditary disorders characterized by chromosomal instability offer a unique window of insight into aging and age-related disease processes. Recently, we discovered a new RECQ helicase disorder, designated RECON syndrome attributed to bi-allelic mutations in the RECQL1 gene (Abu-Libdeh et al., 2022). Cells deficient in RECQL1 exhibit genomic instability and a compromised response to replication stress, providing further evidence for the significance of genome homeostasis to suppress disease phenotypes. Here we provide a perspective on the pathology of RECON syndrome to inform the reader as to how molecular defects in the RECQL1 gene contribute to underlying deficiencies in nucleic acid metabolism often seen in certain aging or age-related diseases.
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Affiliation(s)
- Arindam Datta
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Joshua A Sommers
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Satpal S Jhujh
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Grant S Stewart
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Robert M Brosh
- Helicases and Genomic Integrity Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA.
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22
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Chen P, De Winne N, De Jaeger G, Ito M, Heese M, Schnittger A. KNO1‐mediated autophagic degradation of the Bloom syndrome complex component RMI1 promotes homologous recombination. EMBO J 2023; 42:e111980. [PMID: 36970874 PMCID: PMC10183828 DOI: 10.15252/embj.2022111980] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 01/30/2023] [Accepted: 03/12/2023] [Indexed: 03/29/2023] Open
Abstract
Homologous recombination (HR) is a key DNA damage repair pathway that is tightly adjusted to the state of a cell. A central regulator of homologous recombination is the conserved helicase-containing Bloom syndrome complex, renowned for its crucial role in maintaining genome integrity. Here, we show that in Arabidopsis thaliana, Bloom complex activity is controlled by selective autophagy. We find that the recently identified DNA damage regulator KNO1 facilitates K63-linked ubiquitination of RMI1, a structural component of the complex, thereby triggering RMI1 autophagic degradation and resulting in increased homologous recombination. Conversely, reduced autophagic activity makes plants hypersensitive to DNA damage. KNO1 itself is also controlled at the level of proteolysis, in this case mediated by the ubiquitin-proteasome system, becoming stabilized upon DNA damage via two redundantly acting deubiquitinases, UBP12 and UBP13. These findings uncover a regulatory cascade of selective and interconnected protein degradation steps resulting in a fine-tuned HR response upon DNA damage.
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23
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Phase separation properties of RPA combine high-affinity ssDNA binding with dynamic condensate functions at telomeres. Nat Struct Mol Biol 2023; 30:451-462. [PMID: 36894693 PMCID: PMC10113159 DOI: 10.1038/s41594-023-00932-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/27/2023] [Indexed: 03/11/2023]
Abstract
RPA has been shown to protect single-stranded DNA (ssDNA) intermediates from instability and breakage. RPA binds ssDNA with sub-nanomolar affinity, yet dynamic turnover is required for downstream ssDNA transactions. How ultrahigh-affinity binding and dynamic turnover are achieved simultaneously is not well understood. Here we reveal that RPA has a strong propensity to assemble into dynamic condensates. In solution, purified RPA phase separates into liquid droplets with fusion and surface wetting behavior. Phase separation is stimulated by sub-stoichiometric amounts of ssDNA, but not RNA or double-stranded DNA, and ssDNA gets selectively enriched in RPA condensates. We find the RPA2 subunit required for condensation and multi-site phosphorylation of the RPA2 N-terminal intrinsically disordered region to regulate RPA self-interaction. Functionally, quantitative proximity proteomics links RPA condensation to telomere clustering and integrity in cancer cells. Collectively, our results suggest that RPA-coated ssDNA is contained in dynamic RPA condensates whose properties are important for genome organization and stability.
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24
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Song H, Shen R, Mahasin H, Guo Y, Wang D. DNA replication: Mechanisms and therapeutic interventions for diseases. MedComm (Beijing) 2023; 4:e210. [PMID: 36776764 PMCID: PMC9899494 DOI: 10.1002/mco2.210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 02/09/2023] Open
Abstract
Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.
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Affiliation(s)
- Hao‐Yun Song
- School of Basic Medical SciencesLanzhou UniversityLanzhouGansuChina
| | - Rong Shen
- School of Basic Medical SciencesLanzhou UniversityLanzhouGansuChina
| | - Hamid Mahasin
- School of Basic Medical SciencesLanzhou UniversityLanzhouGansuChina
| | - Ya‐Nan Guo
- School of Basic Medical SciencesLanzhou UniversityLanzhouGansuChina
| | - De‐Gui Wang
- School of Basic Medical SciencesLanzhou UniversityLanzhouGansuChina
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25
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Soniat MM, Nguyen G, Kuo HC, Finkelstein IJ. The MRN complex and topoisomerase IIIa-RMI1/2 synchronize DNA resection motor proteins. J Biol Chem 2023; 299:102802. [PMID: 36529288 PMCID: PMC9971906 DOI: 10.1016/j.jbc.2022.102802] [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: 06/21/2022] [Revised: 12/08/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
DNA resection-the nucleolytic processing of broken DNA ends-is the first step of homologous recombination. Resection is catalyzed by the resectosome, a multienzyme complex that includes bloom syndrome helicase (BLM), DNA2 or exonuclease 1 nucleases, and additional DNA-binding proteins. Although the molecular players have been known for over a decade, how the individual proteins work together to regulate DNA resection remains unknown. Using single-molecule imaging, we characterized the roles of the MRE11-RAD50-NBS1 complex (MRN) and topoisomerase IIIa (TOP3A)-RMI1/2 during long-range DNA resection. BLM partners with TOP3A-RMI1/2 to form the BTRR (BLM-TOP3A-RMI1/2) complex (or BLM dissolvasome). We determined that TOP3A-RMI1/2 aids BLM in initiating DNA unwinding, and along with MRN, stimulates DNA2-mediated resection. Furthermore, we found that MRN promotes the association between BTRR and DNA and synchronizes BLM and DNA2 translocation to prevent BLM from pausing during resection. Together, this work provides direct observation of how MRN and DNA2 harness the BTRR complex to resect DNA efficiently and how TOP3A-RMI1/2 regulates the helicase activity of BLM to promote efficient DNA repair.
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Affiliation(s)
- Michael M Soniat
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA.
| | - Giaochau Nguyen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Hung-Che Kuo
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA.
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26
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Hodson C, van Twest S, Dylewska M, O'Rourke JJ, Tan W, Murphy VJ, Walia M, Abbouche L, Nieminuszczy J, Dunn E, Bythell-Douglas R, Heierhorst J, Niedzwiedz W, Deans AJ. Branchpoint translocation by fork remodelers as a general mechanism of R-loop removal. Cell Rep 2022; 41:111749. [PMID: 36476850 DOI: 10.1016/j.celrep.2022.111749] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/05/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Co-transcriptional R loops arise from stalling of RNA polymerase, leading to the formation of stable DNA:RNA hybrids. Unresolved R loops promote genome instability but are counteracted by helicases and nucleases. Here, we show that branchpoint translocases are a third class of R-loop-displacing enzyme in vitro. In cells, deficiency in the Fanconi-anemia-associated branchpoint translocase FANCM causes R-loop accumulation, particularly after treatment with DNA:RNA-hybrid-stabilizing agents. This correlates with FANCM localization at R-loop-prone regions of the genome. Moreover, other branchpoint translocases associated with human disease, such as SMARCAL1 and ZRANB3, and those from lower organisms can also remove R loops in vitro. Branchpoint translocases are more potent than helicases in resolving R loops, indicating their evolutionary important role in R-loop suppression. In human cells, FANCM, SMARCAL1, and ZRANB3 depletion causes additive effects on R-loop accumulation and DNA damage. Our work reveals a mechanistic basis for R-loop displacement that is linked to genome stability.
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Affiliation(s)
- Charlotte Hodson
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Sylvie van Twest
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Julienne J O'Rourke
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Winnie Tan
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Vincent J Murphy
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Mannu Walia
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Lara Abbouche
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Elyse Dunn
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Rohan Bythell-Douglas
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Jörg Heierhorst
- Department of Medicine (St Vincent's Health), University of Melbourne, Fitzroy, VIC 3065, Australia; Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Andrew J Deans
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine (St Vincent's Health), University of Melbourne, Fitzroy, VIC 3065, Australia.
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27
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Zhang Y, Wu L, Wang Z, Wang J, Roychoudhury S, Tomasik B, Wu G, Wang G, Rao X, Zhou R. Replication Stress: A Review of Novel Targets to Enhance Radiosensitivity-From Bench to Clinic. Front Oncol 2022; 12:838637. [PMID: 35875060 PMCID: PMC9305609 DOI: 10.3389/fonc.2022.838637] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 06/15/2022] [Indexed: 11/22/2022] Open
Abstract
DNA replication is a process fundamental in all living organisms in which deregulation, known as replication stress, often leads to genomic instability, a hallmark of cancer. Most malignant tumors sustain persistent proliferation and tolerate replication stress via increasing reliance to the replication stress response. So whilst replication stress induces genomic instability and tumorigenesis, the replication stress response exhibits a unique cancer-specific vulnerability that can be targeted to induce catastrophic cell proliferation. Radiation therapy, most used in cancer treatment, induces a plethora of DNA lesions that affect DNA integrity and, in-turn, DNA replication. Owing to radiation dose limitations for specific organs and tumor tissue resistance, the therapeutic window is narrow. Thus, a means to eliminate or reduce tumor radioresistance is urgently needed. Current research trends have highlighted the potential of combining replication stress regulators with radiation therapy to capitalize on the high replication stress of tumors. Here, we review the current body of evidence regarding the role of replication stress in tumor progression and discuss potential means of enhancing tumor radiosensitivity by targeting the replication stress response. We offer new insights into the possibility of combining radiation therapy with replication stress drugs for clinical use.
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Affiliation(s)
- Yuewen Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Wu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhao Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinpeng Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shrabasti Roychoudhury
- Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, United States
| | - Bartlomiej Tomasik
- Department of Oncology and Radiotherapy, Medical University of Gdansk, Gdansk, Poland
| | - Gang Wu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Geng Wang
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinrui Rao
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Zhou
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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28
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de Renty C, Pond KW, Yagle MK, Ellis NA. BLM Sumoylation Is Required for Replication Stability and Normal Fork Velocity During DNA Replication. Front Mol Biosci 2022; 9:875102. [PMID: 35847987 PMCID: PMC9284272 DOI: 10.3389/fmolb.2022.875102] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
BLM is sumoylated in response to replication stress. We have studied the role of BLM sumoylation in physiologically normal and replication-stressed conditions by expressing in BLM-deficient cells a BLM with SUMO acceptor-site mutations, which we refer to as SUMO-mutant BLM cells. SUMO-mutant BLM cells exhibited multiple defects in both stressed and unstressed DNA replication conditions, including, in hydroxyurea-treated cells, reduced fork restart and increased fork collapse and, in untreated cells, slower fork velocity and increased fork instability as assayed by track-length asymmetry. We further showed by fluorescence recovery after photobleaching that SUMO-mutant BLM protein was less dynamic than normal BLM and comprised a higher immobile fraction at collapsed replication forks. BLM sumoylation has previously been linked to the recruitment of RAD51 to stressed forks in hydroxyurea-treated cells. An important unresolved question is whether the failure to efficiently recruit RAD51 is the explanation for replication stress in untreated SUMO-mutant BLM cells.
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Affiliation(s)
- Christelle de Renty
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Kelvin W. Pond
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Mary K. Yagle
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Nathan A. Ellis
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, United States
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29
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Xue C, Salunkhe SJ, Tomimatsu N, Kawale AS, Kwon Y, Burma S, Sung P, Greene EC. Bloom helicase mediates formation of large single-stranded DNA loops during DNA end processing. Nat Commun 2022; 13:2248. [PMID: 35473934 PMCID: PMC9042962 DOI: 10.1038/s41467-022-29937-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/14/2022] [Indexed: 01/27/2023] Open
Abstract
Bloom syndrome (BS) is associated with a profoundly increased cancer risk and is caused by mutations in the Bloom helicase (BLM). BLM is involved in the nucleolytic processing of the ends of DNA double-strand breaks (DSBs), to yield long 3' ssDNA tails that serve as the substrate for break repair by homologous recombination (HR). Here, we use single-molecule imaging to demonstrate that BLM mediates formation of large ssDNA loops during DNA end processing. A BLM mutant lacking the N-terminal domain (NTD) retains vigorous in vitro end processing activity but fails to generate ssDNA loops. This same mutant supports DSB end processing in cells, however, these cells do not form RAD51 DNA repair foci and the processed DSBs are channeled into synthesis-dependent strand annealing (SSA) instead of HR-mediated repair, consistent with a defect in RAD51 filament formation. Together, our results provide insights into BLM functions during homologous recombination.
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Affiliation(s)
- Chaoyou Xue
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Sameer J Salunkhe
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
- The Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Nozomi Tomimatsu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Ajinkya S Kawale
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
- The Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Sandeep Burma
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
- Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
- The Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA.
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30
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A POLD3/BLM dependent pathway handles DSBs in transcribed chromatin upon excessive RNA:DNA hybrid accumulation. Nat Commun 2022; 13:2012. [PMID: 35440629 PMCID: PMC9019021 DOI: 10.1038/s41467-022-29629-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 03/25/2022] [Indexed: 12/03/2022] Open
Abstract
Transcriptionally active loci are particularly prone to breakage and mounting evidence suggests that DNA Double-Strand Breaks arising in active genes are handled by a dedicated repair pathway, Transcription-Coupled DSB Repair (TC-DSBR), that entails R-loop accumulation and dissolution. Here, we uncover a function for the Bloom RecQ DNA helicase (BLM) in TC-DSBR in human cells. BLM is recruited in a transcription dependent-manner at DSBs where it fosters resection, RAD51 binding and accurate Homologous Recombination repair. However, in an R-loop dissolution-deficient background, we find that BLM promotes cell death. We report that upon excessive RNA:DNA hybrid accumulation, DNA synthesis is enhanced at DSBs, in a manner that depends on BLM and POLD3. Altogether our work unveils a role for BLM at DSBs in active chromatin, and highlights the toxic potential of RNA:DNA hybrids that accumulate at transcription-associated DSBs. DNA Double Strand breaks in transcriptionally active loci (TC-DSBs) undergo a dedicated repair pathway. Here, the authors show that excessive RNA:DNA hybrid accumulation at TC-DSBs elicits POLD3/BLM-dependent DNA synthesis that induces cell toxicity.
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31
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Pommier Y, Nussenzweig A, Takeda S, Austin C. Human topoisomerases and their roles in genome stability and organization. Nat Rev Mol Cell Biol 2022; 23:407-427. [PMID: 35228717 PMCID: PMC8883456 DOI: 10.1038/s41580-022-00452-3] [Citation(s) in RCA: 137] [Impact Index Per Article: 68.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2022] [Indexed: 12/15/2022]
Abstract
Human topoisomerases comprise a family of six enzymes: two type IB (TOP1 and mitochondrial TOP1 (TOP1MT), two type IIA (TOP2A and TOP2B) and two type IA (TOP3A and TOP3B) topoisomerases. In this Review, we discuss their biochemistry and their roles in transcription, DNA replication and chromatin remodelling, and highlight the recent progress made in understanding TOP3A and TOP3B. Because of recent advances in elucidating the high-order organization of the genome through chromatin loops and topologically associating domains (TADs), we integrate the functions of topoisomerases with genome organization. We also discuss the physiological and pathological formation of irreversible topoisomerase cleavage complexes (TOPccs) as they generate topoisomerase DNA–protein crosslinks (TOP-DPCs) coupled with DNA breaks. We discuss the expanding number of redundant pathways that repair TOP-DPCs, and the defects in those pathways, which are increasingly recognized as source of genomic damage leading to neurological diseases and cancer. Topoisomerases have essential roles in transcription, DNA replication, chromatin remodelling and, as recently revealed, 3D genome organization. However, topoisomerases also generate DNA–protein crosslinks coupled with DNA breaks, which are increasingly recognized as a source of disease-causing genomic damage.
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32
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Maity J, Horibata S, Zurcher G, Lee JM. Targeting of RecQ Helicases as a Novel Therapeutic Strategy for Ovarian Cancer. Cancers (Basel) 2022; 14:cancers14051219. [PMID: 35267530 PMCID: PMC8909030 DOI: 10.3390/cancers14051219] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/16/2022] Open
Abstract
RecQ helicases are essential for DNA replication, recombination, DNA damage repair, and other nucleic acid metabolic pathways required for normal cell growth, survival, and genome stability. More recently, RecQ helicases have been shown to be important for replication fork stabilization, one of the major mechanisms of PARP inhibitor resistance. Cancer cells often have upregulated helicases and depend on these enzymes to repair rapid growth-promoted DNA lesions. Several studies are now evaluating the use of RecQ helicases as potential biomarkers of breast and gynecologic cancers. Furthermore, RecQ helicases have attracted interest as possible targets for cancer treatment. In this review, we discuss the characteristics of RecQ helicases and their interacting partners that may be utilized for effective treatment strategies (as cancers depend on helicases for survival). We also discuss how targeting helicase in combination with DNA repair inhibitors (i.e., PARP and ATR inhibitors) can be used as novel approaches for cancer treatment to increase sensitivity to current treatment to prevent rise of treatment resistance.
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Affiliation(s)
- Jyotirindra Maity
- Women’s Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (J.M.); (G.Z.)
| | - Sachi Horibata
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Precision Health Program, Michigan State University, East Lansing, MI 48824, USA
- Department of Pharmacology and Toxicology, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA
- Correspondence: (S.H.); (J.M.L.)
| | - Grant Zurcher
- Women’s Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (J.M.); (G.Z.)
| | - Jung-Min Lee
- Women’s Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (J.M.); (G.Z.)
- Correspondence: (S.H.); (J.M.L.)
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33
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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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Hodson C, Low JKK, van Twest S, Jones SE, Swuec P, Murphy V, Tsukada K, Fawkes M, Bythell-Douglas R, Davies A, Holien JK, O'Rourke JJ, Parker BL, Glaser A, Parker MW, Mackay JP, Blackford AN, Costa A, Deans AJ. Mechanism of Bloom syndrome complex assembly required for double Holliday junction dissolution and genome stability. Proc Natl Acad Sci U S A 2022; 119:e2109093119. [PMID: 35115399 PMCID: PMC8832983 DOI: 10.1073/pnas.2109093119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 12/17/2021] [Indexed: 12/29/2022] Open
Abstract
The RecQ-like helicase BLM cooperates with topoisomerase IIIα, RMI1, and RMI2 in a heterotetrameric complex (the "Bloom syndrome complex") for dissolution of double Holliday junctions, key intermediates in homologous recombination. Mutations in any component of the Bloom syndrome complex can cause genome instability and a highly cancer-prone disorder called Bloom syndrome. Some heterozygous carriers are also predisposed to breast cancer. To understand how the activities of BLM helicase and topoisomerase IIIα are coupled, we purified the active four-subunit complex. Chemical cross-linking and mass spectrometry revealed a unique architecture that links the helicase and topoisomerase domains. Using biochemical experiments, we demonstrated dimerization mediated by the N terminus of BLM with a 2:2:2:2 stoichiometry within the Bloom syndrome complex. We identified mutations that independently abrogate dimerization or association of BLM with RMI1, and we show that both are dysfunctional for dissolution using in vitro assays and cause genome instability and synthetic lethal interactions with GEN1/MUS81 in cells. Truncated BLM can also inhibit the activity of full-length BLM in mixed dimers, suggesting a putative mechanism of dominant-negative action in carriers of BLM truncation alleles. Our results identify critical molecular determinants of Bloom syndrome complex assembly required for double Holliday junction dissolution and maintenance of genome stability.
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Affiliation(s)
- Charlotte Hodson
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Jason K K Low
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Sylvie van Twest
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Samuel E Jones
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Paolo Swuec
- Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Vincent Murphy
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Kaima Tsukada
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Matthew Fawkes
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Rohan Bythell-Douglas
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Department of Medicine (St. Vincent's), University of Melbourne, Fitzroy, VIC 3065, Australia
| | | | - Jessica K Holien
- Department of Medicine (St. Vincent's), University of Melbourne, Fitzroy, VIC 3065, Australia
- School of Science, RMIT University, Melbourne, VIC 3001, Australia
- Structural Biology Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Julienne J O'Rourke
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Benjamin L Parker
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Astrid Glaser
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Michael W Parker
- Structural Biology Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
- Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Joel P Mackay
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Andrew N Blackford
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | | | - Andrew J Deans
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia;
- Department of Medicine (St. Vincent's), University of Melbourne, Fitzroy, VIC 3065, Australia
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35
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Balbo Pogliano C, Ceppi I, Giovannini S, Petroulaki V, Palmer N, Uliana F, Gatti M, Kasaciunaite K, Freire R, Seidel R, Altmeyer M, Cejka P, Matos J. The CDK1-TOPBP1-PLK1 axis regulates the Bloom's syndrome helicase BLM to suppress crossover recombination in somatic cells. SCIENCE ADVANCES 2022; 8:eabk0221. [PMID: 35119917 PMCID: PMC8816346 DOI: 10.1126/sciadv.abk0221] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Bloom's syndrome is caused by inactivation of the BLM helicase, which functions with TOP3A and RMI1-2 (BTR complex) to dissolve recombination intermediates and avoid somatic crossing-over. We show here that crossover avoidance by BTR further requires the activity of cyclin-dependent kinase-1 (CDK1), Polo-like kinase-1 (PLK1), and the DDR mediator protein TOPBP1, which act in the same pathway. Mechanistically, CDK1 phosphorylates BLM and TOPBP1 and promotes the interaction of both proteins with PLK1. This is amplified by the ability of TOPBP1 to facilitate phosphorylation of BLM at sites that stimulate both BLM-PLK1 and BLM-TOPBP1 binding, creating a positive feedback loop that drives rapid BLM phosphorylation at the G2-M transition. In vitro, BLM phosphorylation by CDK/PLK1/TOPBP1 stimulates the dissolution of topologically linked DNA intermediates by BLM-TOP3A. Thus, we propose that the CDK1-TOPBP1-PLK1 axis enhances BTR-mediated dissolution of recombination intermediates late in the cell cycle to suppress crossover recombination and curtail genomic instability.
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Affiliation(s)
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), 6500 Bellinzona, Switzerland
| | - Sara Giovannini
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Vasiliki Petroulaki
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Nathan Palmer
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Federico Uliana
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Marco Gatti
- Department of Molecular Mechanisms of Disease, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Kristina Kasaciunaite
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103 Leipzig, Germany
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias–FIISC, Ofra s/n, 38320 La Laguna, Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Tenerife, Spain
- Universidad Fernando Pessoa Canarias, 35450 Las Palmas de Gran Canaria, Spain
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103 Leipzig, Germany
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Petr Cejka
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), 6500 Bellinzona, Switzerland
| | - Joao Matos
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Vienna, Austria
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36
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Hu C, Bugbee T, Dacus D, Palinski R, Wallace N. Beta human papillomavirus 8 E6 allows colocalization of non-homologous end joining and homologous recombination repair factors. PLoS Pathog 2022; 18:e1010275. [PMID: 35148356 PMCID: PMC8836322 DOI: 10.1371/journal.ppat.1010275] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Beta human papillomavirus (β-HPV) are hypothesized to make DNA damage more mutagenic and potentially more carcinogenic. Double strand breaks (DSBs) are the most deleterious DNA lesion. They are typically repaired by homologous recombination (HR) or non-homologous end joining (NHEJ). HR occurs after DNA replication while NHEJ can occur at any point in the cell cycle. HR and NHEJ are not thought to occur in the same cell at the same time. HR is restricted to cells in phases of the cell cycle where homologous templates are available, while NHEJ occurs primarily during G1. β-HPV type 8 protein E6 (8E6) attenuates both repair pathways. We use a series of immunofluorescence microscopy and flow cytometry experiments to better define the impact of this attenuation. We found that 8E6 causes colocalization of HR factors (RPA70 and RAD51) with an NHEJ factor (activated DNA-PKcs or pDNA-PKcs) at persistent DSBs. 8E6 also causes RAD51 foci to form during G1. The initiation of NHEJ and HR at the same lesion could lead to antagonistic DNA end processing. Further, HR cannot be readily completed in an error-free manner during G1. Both aberrant repair events would cause deletions. To determine if these mutations were occurring, we used next generation sequencing of the 200kb surrounding a CAS9-induced DSB. 8E6 caused a 21-fold increase in deletions. Chemical and genetic inhibition of p300 as well as an 8E6 mutant that is incapable of destabilizing p300 demonstrates that 8E6 is acting via p300 destabilization. More specific chemical inhibitors of DNA repair provided mechanistic insight by mimicking 8E6-induced dysregulation of DNA repair in a virus-free system. Specifically, inhibition of NHEJ causes RAD51 foci to form in G1 and colocalization of RAD51 with pDNA-PKcs. Our previous work shows that a master transcription regulator, p300, facilitates two major DNA double strand break (DSB) repair pathways: non-homologous end joining (NHEJ) and homologous recombination (HR). By degrading p300, beta genus human papillomavirus 8 protein E6 (8E6) hinders pDNA-PKcs resolution, an essential step during NHEJ. NHEJ and HR are known to compete, with only one pathway initiating repair of a DSB. NHEJ tends to be used in G1 and HR occurs in S/G2. Here, we show that 8E6 allows NHEJ and HR to initiate at the same break site. We show that 8E6 allows HR to initiate in G1, suggesting that NHEJ starts but fails before HR is initiated at the same DSB. Next generation sequencing of the region surrounding a CAS9-induced DSB supports our hypothesis that this dysregulation of DSB repair is mutagenic as 8E6 caused a 15- to 20-fold increase in mutations associated with a CAS9-induced DSB. These studies support the putative role of HPV8 infections in non-melanoma skin cancer development.
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Affiliation(s)
- Changkun Hu
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Taylor Bugbee
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Dalton Dacus
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Rachel Palinski
- Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, Kansas, United States of America
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, United States of America
| | - Nicholas Wallace
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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Hacker L, Capdeville N, Feller L, Enderle-Kukla J, Dorn A, Puchta H. The DNA-dependent protease AtWSS1A suppresses persistent double strand break formation during replication. THE NEW PHYTOLOGIST 2022; 233:1172-1187. [PMID: 34761387 DOI: 10.1111/nph.17848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
The protease WSS1A is an important factor in the repair of DNA-protein crosslinks in plants. Here we show that the loss of WSS1A leads to a reduction of 45S rDNA repeats and chromosomal fragmentation in Arabidopsis. Moreover, in the absence of any factor of the RTR (RECQ4A/TOP3α/RMI1/2) complex, which is involved in the dissolution of DNA replication intermediates, WSS1A becomes essential for viability. If WSS1A loss is combined with loss of the classical (c) or alternative (a) nonhomologous end joining (NHEJ) pathways of double-strand break (DSB) repair, the resulting mutants show proliferation defects and enhanced chromosome fragmentation, which is especially aggravated in the absence of aNHEJ. This indicates that WSS1A is involved either in the suppression of DSB formation or in DSB repair itself. To test the latter we induced DSB by CRISPR/Cas9 at different loci in wild-type and mutant cells and analyzed their repair by deep sequencing. However, no change in the quality of the repair events and only a slight increase in their quantity was found. Thus, by removing complex DNA-protein structures, WSS1A seems to be required for the repair of replication intermediates which would otherwise be resolved into persistent DSB leading to genome instability.
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Affiliation(s)
- Leonie Hacker
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Niklas Capdeville
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Laura Feller
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Janina Enderle-Kukla
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Annika Dorn
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
| | - Holger Puchta
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, Karlsruhe, 76131, Germany
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38
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RQC helical hairpin in Bloom's syndrome helicase regulates DNA unwinding by dynamically intercepting nascent nucleotides. iScience 2022; 25:103606. [PMID: 35005551 PMCID: PMC8718986 DOI: 10.1016/j.isci.2021.103606] [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] [Received: 07/07/2021] [Revised: 11/03/2021] [Accepted: 12/08/2021] [Indexed: 11/24/2022] Open
Abstract
The RecQ family of helicases are important for maintenance of genomic integrity. Although functions of constructive subdomains of this family of helicases have been extensively studied, the helical hairpin (HH) in the RecQ-C-terminal domain (RQC) has been underappreciated and remains poorly understood. Here by using single-molecule fluorescence resonance energy transfer, we found that HH in the human BLM transiently intercepts different numbers of nucleotides when it is unwinding a double-stranded DNA. Single-site mutations in HH that disrupt hydrogen bonds and/or salt bridges between DNA and HH change the DNA binding conformations and the unwinding features significantly. Our results, together with recent clinical tests that correlate single-site mutations in HH of human BLM with the phenotype of cancer-predisposing syndrome or Bloom's syndrome, implicate pivotal roles of HH in BLM's DNA unwinding activity. Similar mechanisms might also apply to other RecQ family helicases, calling for more attention to the RQC helical hairpin.
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39
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Ellis N, Zhu J, Yagle MK, Yang WC, Huang J, Kwako A, Seidman MM, Matunis MJ. RNF4 Regulates the BLM Helicase in Recovery From Replication Fork Collapse. Front Genet 2021; 12:753535. [PMID: 34868226 PMCID: PMC8633118 DOI: 10.3389/fgene.2021.753535] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/25/2021] [Indexed: 12/01/2022] Open
Abstract
Sumoylation is an important enhancer of responses to DNA replication stress and the SUMO-targeted ubiquitin E3 ligase RNF4 regulates these responses by ubiquitylation of sumoylated DNA damage response factors. The specific targets and functional consequences of RNF4 regulation in response to replication stress, however, have not been fully characterized. Here we demonstrated that RNF4 is required for the restart of DNA replication following prolonged hydroxyurea (HU)-induced replication stress. Contrary to its role in repair of γ-irradiation-induced DNA double-strand breaks (DSBs), our analysis revealed that RNF4 does not significantly impact recognition or repair of replication stress-associated DSBs. Rather, using DNA fiber assays, we found that the firing of new DNA replication origins, which is required for replication restart following prolonged stress, was inhibited in cells depleted of RNF4. We also provided evidence that RNF4 recognizes and ubiquitylates sumoylated Bloom syndrome DNA helicase BLM and thereby promotes its proteosome-mediated turnover at damaged DNA replication forks. Consistent with it being a functionally important RNF4 substrate, co-depletion of BLM rescued defects in the firing of new replication origins observed in cells depleted of RNF4 alone. We concluded that RNF4 acts to remove sumoylated BLM from collapsed DNA replication forks, which is required to facilitate normal resumption of DNA synthesis after prolonged replication fork stalling and collapse.
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Affiliation(s)
- Nathan Ellis
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Jianmei Zhu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Mary K Yagle
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Wei-Chih Yang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Jing Huang
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, United States
| | - Alexander Kwako
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, United States
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, United States
| | - Michael J Matunis
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
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40
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Hydroxyurea-The Good, the Bad and the Ugly. Genes (Basel) 2021; 12:genes12071096. [PMID: 34356112 PMCID: PMC8304116 DOI: 10.3390/genes12071096] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/23/2023] Open
Abstract
Hydroxyurea (HU) is mostly referred to as an inhibitor of ribonucleotide reductase (RNR) and as the agent that is commonly used to arrest cells in the S-phase of the cycle by inducing replication stress. It is a well-known and widely used drug, one which has proved to be effective in treating chronic myeloproliferative disorders and which is considered a staple agent in sickle anemia therapy and—recently—a promising factor in preventing cognitive decline in Alzheimer’s disease. The reversibility of HU-induced replication inhibition also makes it a common laboratory ingredient used to synchronize cell cycles. On the other hand, prolonged treatment or higher dosage of hydroxyurea causes cell death due to accumulation of DNA damage and oxidative stress. Hydroxyurea treatments are also still far from perfect and it has been suggested that it facilitates skin cancer progression. Also, recent studies have shown that hydroxyurea may affect a larger number of enzymes due to its less specific interaction mechanism, which may contribute to further as-yet unspecified factors affecting cell response. In this review, we examine the actual state of knowledge about hydroxyurea and the mechanisms behind its cytotoxic effects. The practical applications of the recent findings may prove to enhance the already existing use of the drug in new and promising ways.
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41
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Spakman D, Bakx JAM, Biebricher AS, Peterman EJG, Wuite GJL, King GA. Unravelling the mechanisms of Type 1A topoisomerases using single-molecule approaches. Nucleic Acids Res 2021; 49:5470-5492. [PMID: 33963870 PMCID: PMC8191776 DOI: 10.1093/nar/gkab239] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/19/2021] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
Topoisomerases are essential enzymes that regulate DNA topology. Type 1A family topoisomerases are found in nearly all living organisms and are unique in that they require single-stranded (ss)DNA for activity. These enzymes are vital for maintaining supercoiling homeostasis and resolving DNA entanglements generated during DNA replication and repair. While the catalytic cycle of Type 1A topoisomerases has been long-known to involve an enzyme-bridged ssDNA gate that allows strand passage, a deeper mechanistic understanding of these enzymes has only recently begun to emerge. This knowledge has been greatly enhanced through the combination of biochemical studies and increasingly sophisticated single-molecule assays based on magnetic tweezers, optical tweezers, atomic force microscopy and Förster resonance energy transfer. In this review, we discuss how single-molecule assays have advanced our understanding of the gate opening dynamics and strand-passage mechanisms of Type 1A topoisomerases, as well as the interplay of Type 1A topoisomerases with partner proteins, such as RecQ-family helicases. We also highlight how these assays have shed new light on the likely functional roles of Type 1A topoisomerases in vivo and discuss recent developments in single-molecule technologies that could be applied to further enhance our understanding of these essential enzymes.
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Affiliation(s)
- Dian Spakman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Julia A M Bakx
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Andreas S Biebricher
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Graeme A King
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
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42
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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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43
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Kavli B, Iveland TS, Buchinger E, Hagen L, Liabakk NB, Aas PA, Obermann TS, Aachmann FL, Slupphaug G. RPA2 winged-helix domain facilitates UNG-mediated removal of uracil from ssDNA; implications for repair of mutagenic uracil at the replication fork. Nucleic Acids Res 2021; 49:3948-3966. [PMID: 33784377 PMCID: PMC8053108 DOI: 10.1093/nar/gkab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 01/14/2023] Open
Abstract
Uracil occurs at replication forks via misincorporation of deoxyuridine monophosphate (dUMP) or via deamination of existing cytosines, which occurs 2-3 orders of magnitude faster in ssDNA than in dsDNA and is 100% miscoding. Tethering of UNG2 to proliferating cell nuclear antigen (PCNA) allows rapid post-replicative removal of misincorporated uracil, but potential 'pre-replicative' removal of deaminated cytosines in ssDNA has been questioned since this could mediate mutagenic translesion synthesis and induction of double-strand breaks. Here, we demonstrate that uracil-DNA glycosylase (UNG), but not SMUG1 efficiently excises uracil from replication protein A (RPA)-coated ssDNA and that this depends on functional interaction between the flexible winged-helix (WH) domain of RPA2 and the N-terminal RPA-binding helix in UNG. This functional interaction is promoted by mono-ubiquitination and diminished by cell-cycle regulated phosphorylations on UNG. Six other human proteins bind the RPA2-WH domain, all of which are involved in DNA repair and replication fork remodelling. Based on this and the recent discovery of the AP site crosslinking protein HMCES, we propose an integrated model in which templated repair of uracil and potentially other mutagenic base lesions in ssDNA at the replication fork, is orchestrated by RPA. The UNG:RPA2-WH interaction may also play a role in adaptive immunity by promoting efficient excision of AID-induced uracils in transcribed immunoglobulin loci.
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Affiliation(s)
- Bodil Kavli
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Tobias S Iveland
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Cancer Clinic, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Edith Buchinger
- NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7034 Trondheim, Norway
| | - Lars Hagen
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Proteomics and Modomics Experimental Core at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
| | - Nina B Liabakk
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Per A Aas
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Tobias S Obermann
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway
| | - Finn L Aachmann
- NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7034 Trondheim, Norway
| | - Geir Slupphaug
- Department of Clinical and Molecular Medicine, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.,Clinic of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.,PROMEC Proteomics and Modomics Experimental Core at NTNU and the Central Norway Regional Health Authority, NO-7491 Trondheim, Norway
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Porras-Agüera JA, Moreno-García J, García-Martínez T, Moreno J, Mauricio JC. Impact of CO 2 overpressure on yeast mitochondrial associated proteome during the "prise de mousse" of sparkling wine production. Int J Food Microbiol 2021; 348:109226. [PMID: 33964807 DOI: 10.1016/j.ijfoodmicro.2021.109226] [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: 12/16/2020] [Revised: 04/07/2021] [Accepted: 04/25/2021] [Indexed: 11/25/2022]
Abstract
The "prise de mousse" stage during sparkling wine elaboration by the traditional method (Champenoise) involves a second fermentation in a sealed bottle followed by a prolonged aging period, known to contribute significantly to the unique organoleptic properties of these wines. During this stage, CO2 overpressure, nutrient starvation and high ethanol concentrations are stress factors that affect yeast cells viability and metabolism. Since mitochondria are responsible for energy generation and are required for cell aging and response to numerous stresses, we hypothesized that these organelles may play an essential role during the prise de mousse. The objective of this study is to characterize the mitochondrial response of a Saccharomyces cerevisiae strain traditionally used in sparkling wine production along the "prise de mousse" and study the effect of CO2 overpressure through a proteomic analysis. We observed that pressure negatively affects the content of mitochondrion-related proteome, especially to those proteins involved in tricarboxylic acid cycle. However, proteins required for the branched-amino acid synthesis, implied in wine aromas, and respiratory chain, also previously reported by transcriptomic analyses, were found over-represented in the sealed bottles. Multivariate analysis of proteins required for tricarboxylic cycle, respiratory chain and amino acid metabolism revealed differences in concentrations, allowing the wine samples to group depending on the time and CO2 overpressure parameters. Ethanol content along the second fermentation could be the main reason for this changing behavior observed at proteomic level. Further research including genetic studies, determination of ROS, characterization of mitochondrial activity and targeted metabolomics analyses is required. The list of mitochondrial proteins provided in this work will lead to a better understanding of the yeast behavior under these conditions of special interest in the wine industry.
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Affiliation(s)
- Juan Antonio Porras-Agüera
- Department of Agricultural Chemistry, Edaphology and Microbiology, Severo Ochoa (C6) building, Agrifood Campus of International Excellence CeiA3, University of Cordoba, Ctra. N-IV-A mm 396, 14014 Cordoba, Spain.
| | - Jaime Moreno-García
- Department of Agricultural Chemistry, Edaphology and Microbiology, Severo Ochoa (C6) building, Agrifood Campus of International Excellence CeiA3, University of Cordoba, Ctra. N-IV-A mm 396, 14014 Cordoba, Spain.
| | - Teresa García-Martínez
- Department of Agricultural Chemistry, Edaphology and Microbiology, Severo Ochoa (C6) building, Agrifood Campus of International Excellence CeiA3, University of Cordoba, Ctra. N-IV-A mm 396, 14014 Cordoba, Spain.
| | - Juan Moreno
- Department of Agricultural Chemistry, Edaphology and Microbiology, Severo Ochoa (C6) building, Agrifood Campus of International Excellence CeiA3, University of Cordoba, Ctra. N-IV-A mm 396, 14014 Cordoba, Spain.
| | - Juan Carlos Mauricio
- Department of Agricultural Chemistry, Edaphology and Microbiology, Severo Ochoa (C6) building, Agrifood Campus of International Excellence CeiA3, University of Cordoba, Ctra. N-IV-A mm 396, 14014 Cordoba, Spain.
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Ababou M. Bloom syndrome and the underlying causes of genetic instability. Mol Genet Metab 2021; 133:35-48. [PMID: 33736941 DOI: 10.1016/j.ymgme.2021.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/01/2021] [Accepted: 03/06/2021] [Indexed: 11/27/2022]
Abstract
Autosomal hereditary recessive diseases characterized by genetic instability are often associated with cancer predisposition. Bloom syndrome (BS), a rare genetic disorder, with <300 cases reported worldwide, combines both. Indeed, patients with Bloom's syndrome are 150 to 300 times more likely to develop cancers than normal individuals. The wide spectrum of cancers developed by BS patients suggests that early initial events occur in BS cells which may also be involved in the initiation of carcinogenesis in the general population and these may be common to several cancers. BS is caused by mutations of both copies of the BLM gene, encoding the RecQ BLM helicase. This review discusses the different aspects of BS and the different cellular functions of BLM in genome surveillance and maintenance through its major roles during DNA replication, repair, and transcription. BLM's activities are essential for the stabilization of centromeric, telomeric and ribosomal DNA sequences, and the regulation of innate immunity. One of the key objectives of this work is to establish a link between BLM functions and the main clinical phenotypes observed in BS patients, as well as to shed new light on the correlation between the genetic instability and diseases such as immunodeficiency and cancer. The different potential implications of the BLM helicase in the tumorigenic process and the use of BLM as new potential target in the field of cancer treatment are also debated.
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Affiliation(s)
- Mouna Ababou
- Laboratory of Human Pathologies Biology, Department of Biology, Faculty of Sciences, University Mohammed V, Rabat, Morocco; Genomic Center of Human Pathologies, Faculty of medicine and Pharmacy, University Mohammed V, Rabat, Morocco.
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Kaur E, Agrawal R, Sengupta S. Functions of BLM Helicase in Cells: Is It Acting Like a Double-Edged Sword? Front Genet 2021; 12:634789. [PMID: 33777104 PMCID: PMC7994599 DOI: 10.3389/fgene.2021.634789] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
DNA damage repair response is an important biological process involved in maintaining the fidelity of the genome in eukaryotes and prokaryotes. Several proteins that play a key role in this process have been identified. Alterations in these key proteins have been linked to different diseases including cancer. BLM is a 3′−5′ ATP-dependent RecQ DNA helicase that is one of the most essential genome stabilizers involved in the regulation of DNA replication, recombination, and both homologous and non-homologous pathways of double-strand break repair. BLM structure and functions are known to be conserved across many species like yeast, Drosophila, mouse, and human. Genetic mutations in the BLM gene cause a rare, autosomal recessive disorder, Bloom syndrome (BS). BS is a monogenic disease characterized by genomic instability, premature aging, predisposition to cancer, immunodeficiency, and pulmonary diseases. Hence, these characteristics point toward BLM being a tumor suppressor. However, in addition to mutations, BLM gene undergoes various types of alterations including increase in the copy number, transcript, and protein levels in multiple types of cancers. These results, along with the fact that the lack of wild-type BLM in these cancers has been associated with increased sensitivity to chemotherapeutic drugs, indicate that BLM also has a pro-oncogenic function. While a plethora of studies have reported the effect of BLM gene mutations in various model organisms, there is a dearth in the studies undertaken to investigate the effect of its oncogenic alterations. We propose to rationalize and integrate the dual functions of BLM both as a tumor suppressor and maybe as a proto-oncogene, and enlist the plausible mechanisms of its deregulation in cancers.
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Affiliation(s)
- Ekjot Kaur
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
| | - Ritu Agrawal
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
| | - Sagar Sengupta
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
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