1
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Paul Chowdhuri S, Das BB. TDP1 phosphorylation by CDK1 in mitosis promotes MUS81-dependent repair of trapped Top1-DNA covalent complexes. EMBO J 2024; 43:3710-3732. [PMID: 39014228 PMCID: PMC11377750 DOI: 10.1038/s44318-024-00169-3] [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: 11/15/2023] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/18/2024] Open
Abstract
Topoisomerase 1 (Top1) controls DNA topology, relieves DNA supercoiling during replication and transcription, and is critical for mitotic progression to the G1 phase. Tyrosyl-DNA phosphodiesterase 1 (TDP1) mediates the removal of trapped Top1-DNA covalent complexes (Top1cc). Here, we identify CDK1-dependent phosphorylation of TDP1 at residue S61 during mitosis. A TDP1 variant defective for S61 phosphorylation (TDP1-S61A) is trapped on the mitotic chromosomes, triggering DNA damage and mitotic defects. Moreover, we show that Top1cc repair in mitosis occurs via a MUS81-dependent DNA repair mechanism. Replication stress induced by camptothecin or aphidicolin leads to TDP1-S61A enrichment at common fragile sites, which over-stimulates MUS81-dependent chromatid breaks, anaphase bridges, and micronuclei, ultimately culminating in the formation of 53BP1 nuclear bodies during G1 phase. Our findings provide new insights into the cell cycle-dependent regulation of TDP1 dynamics for the repair of trapped Top1-DNA covalent complexes during mitosis that prevents genomic instability following replication stress.
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Affiliation(s)
- Srijita Paul Chowdhuri
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India
| | - Benu Brata Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal, 700032, India.
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2
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Lee S, Lee S, Choi N, Kim J, Kweon J, Miller K, Kim J. PCAF promotes R-loop resolution via histone acetylation. Nucleic Acids Res 2024; 52:8643-8660. [PMID: 38936834 PMCID: PMC11347145 DOI: 10.1093/nar/gkae558] [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: 03/05/2024] [Revised: 06/04/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024] Open
Abstract
R-loops cause genome instability, disrupting normal cellular functions. Histone acetylation, particularly by p300/CBP-associated factor (PCAF), is essential for maintaining genome stability and regulating cellular processes. Understanding how R-loop formation and resolution are regulated is important because dysregulation of these processes can lead to multiple diseases, including cancer. This study explores the role of PCAF in maintaining genome stability, specifically for R-loop resolution. We found that PCAF depletion promotes the generation of R-loop structures, especially during ongoing transcription, thereby compromising genome stability. Mechanistically, we found that PCAF facilitates histone H4K8 acetylation, leading to recruitment of the a double-strand break repair protein (MRE11) and exonuclease 1 (EXO1) to R-loop sites. These in turn recruit Fanconi anemia (FA) proteins, including FANCM and BLM, to resolve the R-loop structure. Our findings suggest that PCAF, histone acetylation, and FA proteins collaborate to resolve R-loops and ensure genome stability. This study therefore provides novel mechanistic insights into the dynamics of R-loops as well as the role of PCAF in preserving genome stability. These results may help develop therapeutic strategies to target diseases associated with genome instability.
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Affiliation(s)
- Seo Yun Lee
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Soo Hyeon Lee
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Nak Hun Choi
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Ja Young Kim
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Jun Hee Kweon
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jae Jin Kim
- Department of Life Science and Multidisciplinary Genome Institute, Hallym University, Chuncheon 24252, Republic of Korea
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3
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Rao S, Andrs M, Shukla K, Isik E, König C, Schneider S, Bauer M, Rosano V, Prokes J, Müller A, Janscak P. Senataxin RNA/DNA helicase promotes replication restart at co-transcriptional R-loops to prevent MUS81-dependent fork degradation. Nucleic Acids Res 2024:gkae673. [PMID: 39119900 DOI: 10.1093/nar/gkae673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 07/12/2024] [Accepted: 07/23/2024] [Indexed: 08/10/2024] Open
Abstract
Replication forks stalled at co-transcriptional R-loops can be restarted by a mechanism involving fork cleavage-religation cycles mediated by MUS81 endonuclease and DNA ligase IV (LIG4), which presumably relieve the topological barrier generated by the transcription-replication conflict (TRC) and facilitate ELL-dependent reactivation of transcription. Here, we report that the restart of R-loop-stalled replication forks via the MUS81-LIG4-ELL pathway requires senataxin (SETX), a helicase that can unwind RNA:DNA hybrids. We found that SETX promotes replication fork progression by preventing R-loop accumulation during S-phase. Interestingly, loss of SETX helicase activity leads to nascent DNA degradation upon induction of R-loop-mediated fork stalling by hydroxyurea. This fork degradation phenotype is independent of replication fork reversal and results from DNA2-mediated resection of MUS81-cleaved replication forks that accumulate due to defective replication restart. Finally, we demonstrate that SETX acts in a common pathway with the DEAD-box helicase DDX17 to suppress R-loop-mediated replication stress in human cells. A possible cooperation between these RNA/DNA helicases in R-loop unwinding at TRC sites is discussed.
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Affiliation(s)
- Satyajeet Rao
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Andrs
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kaustubh Shukla
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Esin Isik
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Christiane König
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefan Schneider
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Michael Bauer
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Vinicio Rosano
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jiri Prokes
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Anne Müller
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Pavel Janscak
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
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4
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Zannini L, Cardano M, Liberi G, Buscemi G. R-loops and impaired autophagy trigger cGAS-dependent inflammation via micronuclei formation in Senataxin-deficient cells. Cell Mol Life Sci 2024; 81:339. [PMID: 39120648 PMCID: PMC11335261 DOI: 10.1007/s00018-024-05380-3] [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: 04/11/2024] [Revised: 07/17/2024] [Accepted: 07/23/2024] [Indexed: 08/10/2024]
Abstract
Senataxin is an evolutionarily conserved DNA/RNA helicase, whose dysfunctions are linked to neurodegeneration and cancer. A main activity of this protein is the removal of R-loops, which are nucleic acid structures capable to promote DNA damage and replication stress. Here we found that Senataxin deficiency causes the release of damaged DNA into extranuclear bodies, called micronuclei, triggering the massive recruitment of cGAS, the apical sensor of the innate immunity pathway, and the downstream stimulation of interferon genes. Such cGAS-positive micronuclei are characterized by defective membrane envelope and are particularly abundant in cycling cells lacking Senataxin, but not after exposure to a DNA breaking agent or in absence of the tumor suppressor BRCA1 protein, a partner of Senataxin in R-loop removal. Micronuclei with a discontinuous membrane are normally cleared by autophagy, a process that we show is impaired in Senataxin-deficient cells. The formation of Senataxin-dependent inflamed micronuclei is promoted by the persistence of nuclear R-loops stimulated by the DSIF transcription elongation complex and the engagement of EXO1 nuclease activity on nuclear DNA. Coherently, high levels of EXO1 result in poor prognosis in a subset of tumors lacking Senataxin expression. Hence, R-loop homeostasis impairment, together with autophagy failure and unscheduled EXO1 activity, elicits innate immune response through micronuclei formation in cells lacking Senataxin.
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Affiliation(s)
- Laura Zannini
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, Pavia, 27100, Italy
| | - Miriana Cardano
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, Pavia, 27100, Italy
| | - Giordano Liberi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, Pavia, 27100, Italy.
| | - Giacomo Buscemi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, Pavia, 27100, Italy.
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5
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Luna R, Gómez-González B, Aguilera A. RNA biogenesis and RNA metabolism factors as R-loop suppressors: a hidden role in genome integrity. Genes Dev 2024; 38:504-527. [PMID: 38986581 PMCID: PMC11293400 DOI: 10.1101/gad.351853.124] [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] [Indexed: 07/12/2024]
Abstract
Genome integrity relies on the accuracy of DNA metabolism, but as appreciated for more than four decades, transcription enhances mutation and recombination frequencies. More recent research provided evidence for a previously unforeseen link between RNA and DNA metabolism, which is often related to the accumulation of DNA-RNA hybrids and R-loops. In addition to physiological roles, R-loops interfere with DNA replication and repair, providing a molecular scenario for the origin of genome instability. Here, we review current knowledge on the multiple RNA factors that prevent or resolve R-loops and consequent transcription-replication conflicts and thus act as modulators of genome dynamics.
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Affiliation(s)
- Rosa Luna
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Spanish National Research Council (CSIC), 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Belén Gómez-González
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Spanish National Research Council (CSIC), 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Spanish National Research Council (CSIC), 41092 Seville, Spain;
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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6
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Yang BZ, Liu MY, Chiu KL, Chien YL, Cheng CA, Chen YL, Tsui LY, Lin KR, Chu HPC, Wu CSP. DHX9 SUMOylation is required for the suppression of R-loop-associated genome instability. Nat Commun 2024; 15:6009. [PMID: 39019926 PMCID: PMC11255299 DOI: 10.1038/s41467-024-50428-4] [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: 09/04/2023] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
RNA helicase DHX9 is essential for genome stability by resolving aberrant R-loops. However, its regulatory mechanisms remain unclear. Here we show that SUMOylation at lysine 120 (K120) is crucial for DHX9 function. Preventing SUMOylation at K120 leads to R-loop dysregulation, increased DNA damage, and cell death. Cells expressing DHX9 K120R mutant which cannot be SUMOylated are more sensitive to genotoxic agents and this sensitivity is mitigated by RNase H overexpression. Unlike the mutant, wild-type DHX9 interacts with R-loop-associated proteins such as PARP1 and DDX21 via SUMO-interacting motifs. Fusion of SUMO2 to the DHX9 K120R mutant enhances its association with these proteins, reduces R-loop accumulation, and alleviates survival defects of DHX9 K120R. Our findings highlight the critical role of DHX9 SUMOylation in maintaining genome stability by regulating protein interactions necessary for R-loop balance.
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Affiliation(s)
- Bing-Ze Yang
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Mei-Yin Liu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Kuan-Lin Chiu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, 106319, Taiwan
| | - Yuh-Ling Chien
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Ching-An Cheng
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Yu-Lin Chen
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Li-Yu Tsui
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Keng-Ru Lin
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | | | - Ching-Shyi Peter Wu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan.
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7
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Xu Y, Jiao Y, Liu C, Miao R, Liu C, Wang Y, Ma C, Liu J. R-loop and diseases: the cell cycle matters. Mol Cancer 2024; 23:84. [PMID: 38678239 PMCID: PMC11055327 DOI: 10.1186/s12943-024-02000-3] [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: 02/11/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024] Open
Abstract
The cell cycle is a crucial biological process that is involved in cell growth, development, and reproduction. It can be divided into G1, S, G2, and M phases, and each period is closely regulated to ensure the production of two similar daughter cells with the same genetic material. However, many obstacles influence the cell cycle, including the R-loop that is formed throughout this process. R-loop is a triple-stranded structure, composed of an RNA: DNA hybrid and a single DNA strand, which is ubiquitous in organisms from bacteria to mammals. The existence of the R-loop has important significance for the regulation of various physiological processes. However, aberrant accumulation of R-loop due to its limited resolving ability will be detrimental for cells. For example, DNA damage and genomic instability, caused by the R-loop, can activate checkpoints in the cell cycle, which in turn induce cell cycle arrest and cell death. At present, a growing number of factors have been proven to prevent or eliminate the accumulation of R-loop thereby avoiding DNA damage and mutations. Therefore, we need to gain detailed insight into the R-loop resolution factors at different stages of the cell cycle. In this review, we review the current knowledge of factors that play a role in resolving the R-loop at different stages of the cell cycle, as well as how mutations of these factors lead to the onset and progression of diseases.
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Affiliation(s)
- Yuqin Xu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yue Jiao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chengbin Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Rui Miao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunyan Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yilong Wang
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunming Ma
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Jiao Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China.
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8
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Isik E, Shukla K, Pospisilova M, König C, Andrs M, Rao S, Rosano V, Dobrovolna J, Krejci L, Janscak P. MutSβ-MutLβ-FANCJ axis mediates the restart of DNA replication after fork stalling at cotranscriptional G4/R-loops. SCIENCE ADVANCES 2024; 10:eadk2685. [PMID: 38324687 PMCID: PMC10849593 DOI: 10.1126/sciadv.adk2685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/08/2024] [Indexed: 02/09/2024]
Abstract
Transcription-replication conflicts (TRCs) induce formation of cotranscriptional RNA:DNA hybrids (R-loops) stabilized by G-quadruplexes (G4s) on the displaced DNA strand, which can cause fork stalling. Although it is known that these stalled forks can resume DNA synthesis in a process initiated by MUS81 endonuclease, how TRC-associated G4/R-loops are removed to allow fork passage remains unclear. Here, we identify the mismatch repair protein MutSβ, an MLH1-PMS1 heterodimer termed MutLβ, and the G4-resolving helicase FANCJ as factors that are required for MUS81-initiated restart of DNA replication at TRC sites in human cells. This DNA repair process depends on the G4-binding activity of MutSβ, the helicase activity of FANCJ, and the binding of FANCJ to MLH1. Furthermore, we show that MutSβ, MutLβ, and MLH1-FANCJ interaction mediate FANCJ recruitment to G4s. These data suggest that MutSβ, MutLβ, and FANCJ act in conjunction to eliminate G4/R-loops at TRC sites, allowing replication restart.
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Affiliation(s)
- Esin Isik
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kaustubh Shukla
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 143 00 Prague, Czech Republic
| | - Michaela Pospisilova
- Department of Biology and National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A7, Brno 62500, Czech Republic
- International Clinical Research Center, St Anne's University Hospital, Pekarska 53, Brno 656 91, Czech Republic
| | - Christiane König
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Andrs
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Satyajeet Rao
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Vinicio Rosano
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jana Dobrovolna
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 143 00 Prague, Czech Republic
| | - Lumir Krejci
- Department of Biology and National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A7, Brno 62500, Czech Republic
- International Clinical Research Center, St Anne's University Hospital, Pekarska 53, Brno 656 91, Czech Republic
| | - Pavel Janscak
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 143 00 Prague, Czech Republic
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9
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Liu MY, Lin KR, Chien YL, Yang BZ, Tsui LY, Chu HP, Wu CSP. ATR phosphorylates DHX9 at serine 321 to suppress R-loop accumulation upon genotoxic stress. Nucleic Acids Res 2024; 52:204-222. [PMID: 37930853 PMCID: PMC10783509 DOI: 10.1093/nar/gkad973] [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: 07/13/2023] [Revised: 09/19/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
Aberrant DNA/RNA hybrids (R-loops) formed during transcription and replication disturbances pose threats to genome stability. DHX9 is an RNA helicase involved in R-loop resolution, but how DHX9 is regulated in response to genotoxic stress remains unclear. Here we report that DHX9 is phosphorylated at S321 and S688, with S321 phosphorylation primarily induced by ATR after DNA damage. Phosphorylation of DHX9 at S321 promotes its interaction with γH2AX, BRCA1 and RPA, and is required for its association with R-loops under genotoxic stress. Inhibition of ATR or expression of the non-phosphorylatable DHX9S321A prevents DHX9 from interacting with RPA and R-loops, leading to the accumulation of stress-induced R-loops. Furthermore, depletion of RPA reduces the association between DHX9 and γH2AX, and in vitro binding analysis confirms a direct interaction between DHX9 and RPA. Notably, cells with the non-phosphorylatable DHX9S321A variant exhibit hypersensitivity to genotoxic stress, while those expressing the phosphomimetic DHX9S321D variant prevent R-loop accumulation and display resistance to DNA damage agents. In summary, we uncover a new mechanism by which ATR directly regulates DHX9 through phosphorylation to eliminate stress-induced R-loops.
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Affiliation(s)
- Mei-Yin Liu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Keng-Ru Lin
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Yuh-Ling Chien
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Bing-Ze Yang
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | - Li-Yu Tsui
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
| | | | - Ching-Shyi Peter Wu
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
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10
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Lee JD, Bae W. Unscheduled excessive R-loops in immune response. Funct Integr Genomics 2024; 24:7. [PMID: 38189844 DOI: 10.1007/s10142-024-01288-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Affiliation(s)
- Jiah D Lee
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Woori Bae
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.
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11
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Abstract
Transcription and replication both require large macromolecular complexes to act on a DNA template, yet these machineries cannot simultaneously act on the same DNA sequence. Conflicts between the replication and transcription machineries (transcription-replication conflicts, or TRCs) are widespread in both prokaryotes and eukaryotes and have the capacity to both cause DNA damage and compromise complete, faithful replication of the genome. This review will highlight recent studies investigating the genomic locations of TRCs and the mechanisms by which they may be prevented, mitigated, or resolved. We address work from both model organisms and mammalian systems but predominantly focus on multicellular eukaryotes owing to the additional complexities inherent in the coordination of replication and transcription in the context of cell type-specific gene expression and higher-order chromatin organization.
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Affiliation(s)
- Liana Goehring
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA;
| | - Tony T Huang
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA;
| | - Duncan J Smith
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, USA;
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12
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Bradley L, Savage KI. 'From R-lupus to cancer': Reviewing the role of R-loops in innate immune responses. DNA Repair (Amst) 2023; 131:103581. [PMID: 37832251 DOI: 10.1016/j.dnarep.2023.103581] [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: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023]
Abstract
Cells possess an inherent and evolutionarily conserved ability to detect and respond to the presence of foreign and pathological 'self' nucleic acids. The result is the stimulation of innate immune responses, signalling to the host immune system that defence mechanisms are necessary to protect the organism. To date, there is a vast body of literature describing innate immune responses to various nucleic acid species, including dsDNA, ssDNA and ssRNA etc., however, there is limited information available on responses to R-loops. R-loops are 3-stranded nucleic acid structures that form during transcription, upon DNA damage and in various other settings. Emerging evidence suggests that innate immune responses may also exist for the detection of R-loop related nucleic acid structures, implicating R-loops as drivers of inflammatory states. In this review, we aim to summarise the evidence indicating that R-loops are immunogenic species that can trigger innate immune responses in physiological and pathological settings and discuss the implications of this in the study of various diseases and therapeutic development.
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Affiliation(s)
- Leanne Bradley
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Rd, Belfast, United Kingdom
| | - Kienan I Savage
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Rd, Belfast, United Kingdom.
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13
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Duardo RC, Guerra F, Pepe S, Capranico G. Non-B DNA structures as a booster of genome instability. Biochimie 2023; 214:176-192. [PMID: 37429410 DOI: 10.1016/j.biochi.2023.07.002] [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: 03/29/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Non-canonical secondary structures (NCSs) are alternative nucleic acid structures that differ from the canonical B-DNA conformation. NCSs often occur in repetitive DNA sequences and can adopt different conformations depending on the sequence. The majority of these structures form in the context of physiological processes, such as transcription-associated R-loops, G4s, as well as hairpins and slipped-strand DNA, whose formation can be dependent on DNA replication. It is therefore not surprising that NCSs play important roles in the regulation of key biological processes. In the last years, increasing published data have supported their biological role thanks to genome-wide studies and the development of bioinformatic prediction tools. Data have also highlighted the pathological role of these secondary structures. Indeed, the alteration or stabilization of NCSs can cause the impairment of transcription and DNA replication, modification in chromatin structure and DNA damage. These events lead to a wide range of recombination events, deletions, mutations and chromosomal aberrations, well-known hallmarks of genome instability which are strongly associated with human diseases. In this review, we summarize molecular processes through which NCSs trigger genome instability, with a focus on G-quadruplex, i-motif, R-loop, Z-DNA, hairpin, cruciform and multi-stranded structures known as triplexes.
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Affiliation(s)
- Renée C Duardo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Federico Guerra
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Simona Pepe
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy.
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14
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Andrs M, Stoy H, Boleslavska B, Chappidi N, Kanagaraj R, Nascakova Z, Menon S, Rao S, Oravetzova A, Dobrovolna J, Surendranath K, Lopes M, Janscak P. Excessive reactive oxygen species induce transcription-dependent replication stress. Nat Commun 2023; 14:1791. [PMID: 36997515 PMCID: PMC10063555 DOI: 10.1038/s41467-023-37341-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Elevated levels of reactive oxygen species (ROS) reduce replication fork velocity by causing dissociation of the TIMELESS-TIPIN complex from the replisome. Here, we show that ROS generated by exposure of human cells to the ribonucleotide reductase inhibitor hydroxyurea (HU) promote replication fork reversal in a manner dependent on active transcription and formation of co-transcriptional RNA:DNA hybrids (R-loops). The frequency of R-loop-dependent fork stalling events is also increased after TIMELESS depletion or a partial inhibition of replicative DNA polymerases by aphidicolin, suggesting that this phenomenon is due to a global replication slowdown. In contrast, replication arrest caused by HU-induced depletion of deoxynucleotides does not induce fork reversal but, if allowed to persist, leads to extensive R-loop-independent DNA breakage during S-phase. Our work reveals a link between oxidative stress and transcription-replication interference that causes genomic alterations recurrently found in human cancer.
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Affiliation(s)
- Martin Andrs
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Barbora Boleslavska
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nagaraja Chappidi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Radhakrishnan Kanagaraj
- Genome Engineering Laboratory, School of Life Sciences, University of Westminster, London, UK
- School of Life Sciences, University of Bedfordshire, Luton, UK
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai, India
| | - Zuzana Nascakova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Shruti Menon
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- School of Medicine, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Satyajeet Rao
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Anna Oravetzova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jana Dobrovolna
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Kalpana Surendranath
- Genome Engineering Laboratory, School of Life Sciences, University of Westminster, London, UK
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai, India
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Pavel Janscak
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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15
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Herrera LR, McGlynn K, Gibbs ZA, Davis AJ, Whitehurst AW. The Cancer Testes Antigen, HORMAD1, is a Tumor-Specific Replication Fork Protection Factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.31.526348. [PMID: 36778501 PMCID: PMC9915569 DOI: 10.1101/2023.01.31.526348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tumors frequently activate the expression of genes that are only otherwise required for meiosis. HORMAD1, which is essential for meiotic recombination in multiple species, is expressed in over 50% of human lung adenocarcinoma cells (LUAD). We previously found that HORMAD1 promotes DNA double strand break (DSB) repair in LUAD. Here, we report that HORMAD1 takes on an additional role in protecting genomic integrity. Specifically, we find HORMAD1 is critical for protecting stalled DNA replication forks in LUAD. Loss of HORMAD1 leads to nascent DNA degradation, an event which is mediated by the MRE11-DNA2-BLM pathway. Moreover, following exogenous induction of DNA replication stress, HORMAD1 deleted cells accumulate single stranded DNA (ssDNA). We find that these phenotypes are the result of a lack of RAD51 and BRCA2 loading onto stalled replication forks. Ultimately, loss of HORMAD1 leads to increased DSBs and chromosomal aberrations in response to replication stress. Collectively, our data support a model where HORMAD1 expression is selected to mitigate DNA replication stress, which would otherwise induce deleterious genomic instability.
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