1
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Ivanov MP, Zecchini H, Hamerlik P. Simultaneous Visualization of R-Loops/RNA:DNA Hybrids and Replication Forks in a DNA Combing Assay. Genes (Basel) 2024; 15:1161. [PMID: 39336752 PMCID: PMC11430951 DOI: 10.3390/genes15091161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 08/22/2024] [Accepted: 08/30/2024] [Indexed: 09/30/2024] Open
Abstract
R-loops, structures that play a crucial role in various biological processes, are integral to gene expression, the maintenance of genome stability, and the formation of epigenomic signatures. When these R-loops are deregulated, they can contribute to the development of serious health conditions, including cancer and neurodegenerative diseases. The detection of R-loops is a complex process that involves several approaches. These include S9.6 antibody- or RNAse H-based immunoprecipitation, non-denaturing bisulfite footprinting, gel electrophoresis, and electron microscopy. Each of these methods offers unique insights into the nature and behavior of R-loops. In our study, we introduce a novel protocol that has been developed based on a single-molecule DNA combing assay. This innovative approach allows for the direct and simultaneous visualization of RNA:DNA hybrids and replication forks, providing a more comprehensive understanding of these structures. Our findings confirm the transcriptional origin of the hybrids, adding to the body of knowledge about their formation. Furthermore, we demonstrate that these hybrids have an inhibitory effect on the progression of replication forks, highlighting their potential impact on DNA replication and cellular function.
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Affiliation(s)
- Miroslav Penchev Ivanov
- Early Oncology Bioscience, AstraZeneca, Cambridge CB2 0AA, UK;
- The Francis Crick Institute, London NW1 1AT, UK
| | - Heather Zecchini
- Light Microscopy Facility, University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge CB2 0RE, UK;
| | - Petra Hamerlik
- Early Oncology Bioscience, AstraZeneca, Cambridge CB2 0AA, UK;
- Division of Cancer Sciences, University of Manchester, Manchester M13 9PL, UK
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2
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Yang S, Kim SH, Yang E, Kang M, Joo JY. Molecular insights into regulatory RNAs in the cellular machinery. Exp Mol Med 2024; 56:1235-1249. [PMID: 38871819 PMCID: PMC11263585 DOI: 10.1038/s12276-024-01239-6] [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: 12/18/2023] [Revised: 02/27/2024] [Accepted: 03/05/2024] [Indexed: 06/15/2024] Open
Abstract
It is apparent that various functional units within the cellular machinery are derived from RNAs. The evolution of sequencing techniques has resulted in significant insights into approaches for transcriptome studies. Organisms utilize RNA to govern cellular systems, and a heterogeneous class of RNAs is involved in regulatory functions. In particular, regulatory RNAs are increasingly recognized to participate in intricately functioning machinery across almost all levels of biological systems. These systems include those mediating chromatin arrangement, transcription, suborganelle stabilization, and posttranscriptional modifications. Any class of RNA exhibiting regulatory activity can be termed a class of regulatory RNA and is typically represented by noncoding RNAs, which constitute a substantial portion of the genome. These RNAs function based on the principle of structural changes through cis and/or trans regulation to facilitate mutual RNA‒RNA, RNA‒DNA, and RNA‒protein interactions. It has not been clearly elucidated whether regulatory RNAs identified through deep sequencing actually function in the anticipated mechanisms. This review addresses the dominant properties of regulatory RNAs at various layers of the cellular machinery and covers regulatory activities, structural dynamics, modifications, associated molecules, and further challenges related to therapeutics and deep learning.
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Affiliation(s)
- Sumin Yang
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, Gyeonggi-do, 15588, Republic of Korea
| | - Sung-Hyun Kim
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, Gyeonggi-do, 15588, Republic of Korea
| | - Eunjeong Yang
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, Gyeonggi-do, 15588, Republic of Korea
| | - Mingon Kang
- Department of Computer Science, University of Nevada, Las Vegas, NV, 89154, USA
| | - Jae-Yeol Joo
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, Gyeonggi-do, 15588, Republic of Korea.
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3
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Duardo RC, Marinello J, Russo M, Morelli S, Pepe S, Guerra F, Gómez-González B, Aguilera A, Capranico G. Human DNA topoisomerase I poisoning causes R loop-mediated genome instability attenuated by transcription factor IIS. SCIENCE ADVANCES 2024; 10:eadm8196. [PMID: 38787953 PMCID: PMC11122683 DOI: 10.1126/sciadv.adm8196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/18/2024] [Indexed: 05/26/2024]
Abstract
DNA topoisomerase I can contribute to cancer genome instability. During catalytic activity, topoisomerase I forms a transient intermediate, topoisomerase I-DNA cleavage complex (Top1cc) to allow strand rotation and duplex relaxation, which can lead to elevated levels of DNA-RNA hybrids and micronuclei. To comprehend the underlying mechanisms, we have integrated genomic data of Top1cc-triggered hybrids and DNA double-strand breaks (DSBs) shortly after Top1cc induction, revealing that Top1ccs increase hybrid levels with different mechanisms. DSBs are at highly transcribed genes in early replicating initiation zones and overlap with hybrids downstream of accumulated RNA polymerase II (RNAPII) at gene 5'-ends. A transcription factor IIS mutant impairing transcription elongation further increased RNAPII accumulation likely due to backtracking. Moreover, Top1ccs can trigger micronuclei when occurring during late G1 or early/mid S, but not during late S. As micronuclei and transcription-replication conflicts are attenuated by transcription factor IIS, our results support a role of RNAPII arrest in Top1cc-induced transcription-replication conflicts leading to DSBs and micronuclei.
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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
| | - Jessica Marinello
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Marco Russo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Sara Morelli
- 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
| | - Federico Guerra
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa—CABIMER, Universidad de Sevilla–CSIC, Calle Américo Vespucio 24, 41092 Seville, Spain
- Departamento de Genetica, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa—CABIMER, Universidad de Sevilla–CSIC, Calle Américo Vespucio 24, 41092 Seville, Spain
- Departamento de Genetica, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
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4
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Rivosecchi J, Jurikova K, Cusanelli E. Telomere-specific regulation of TERRA and its impact on telomere stability. Semin Cell Dev Biol 2024; 157:3-23. [PMID: 38088000 DOI: 10.1016/j.semcdb.2023.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 11/02/2023] [Indexed: 01/08/2024]
Abstract
TERRA is a class of telomeric repeat-containing RNAs that are expressed from telomeres in multiple organisms. TERRA transcripts play key roles in telomere maintenance and their physiological levels are essential to maintain the integrity of telomeric DNA. Indeed, deregulated TERRA expression or its altered localization can impact telomere stability by multiple mechanisms including fueling transcription-replication conflicts, promoting resection of chromosome ends, altering the telomeric chromatin, and supporting homologous recombination. Therefore, a fine-tuned control of TERRA is important to maintain the integrity of the genome. Several studies have reported that different cell lines express substantially different levels of TERRA. Most importantly, TERRA levels markedly vary among telomeres of a given cell type, indicating the existence of telomere-specific regulatory mechanisms which may help coordinate TERRA functions. TERRA molecules contain distinct subtelomeric sequences, depending on their telomere of origin, which may instruct specific post-transcriptional modifications or mediate distinct functions. In addition, all TERRA transcripts share a repetitive G-rich sequence at their 3' end which can form DNA:RNA hybrids and fold into G-quadruplex structures. Both structures are involved in TERRA functions and can critically affect telomere stability. In this review, we examine the mechanisms controlling TERRA levels and the impact of their telomere-specific regulation on telomere stability. We compare evidence obtained in different model organisms, discussing recent advances as well as controversies in the field. Furthermore, we discuss the importance of DNA:RNA hybrids and G-quadruplex structures in the context of TERRA biology and telomere maintenance.
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Affiliation(s)
- Julieta Rivosecchi
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Katarina Jurikova
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy; Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina, 84215 Bratislava, Slovakia
| | - Emilio Cusanelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy.
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5
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Dowling JW, Smith JR, Forero A. Protocol for detection of in vitro R-loop formation using dot blots. STAR Protoc 2024; 5:102857. [PMID: 38285737 PMCID: PMC10839531 DOI: 10.1016/j.xpro.2024.102857] [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: 10/18/2023] [Revised: 11/30/2023] [Accepted: 01/15/2024] [Indexed: 01/31/2024] Open
Abstract
Dot-blot analysis is a technique that allows for fast and convenient detection and identification of nucleic acids and proteins. Here, we provide a guide for nucleic acid isolation from eukaryotic cells and sample processing to detect RNA/DNA hybrids. We then provide detailed steps to quantify dot signal intensity. This protocol can be adapted for screening conditions that result in the accumulation of R-loops. For complete details on the use and execution of this protocol, please refer to Smith et al.1.
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Affiliation(s)
- Jack W Dowling
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Julian R Smith
- Department of Immunology, University of Washington, Seattle, WA 98109, USA
| | - Adriana Forero
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
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6
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Feró O, Varga D, Nagy É, Karányi Z, Sipos É, Engelhardt J, Török N, Balogh I, Vető B, Likó I, Fóthi Á, Szabó Z, Halmos G, Vécsei L, Arányi T, Székvölgyi L. DNA methylome, R-loop and clinical exome profiling of patients with sporadic amyotrophic lateral sclerosis. Sci Data 2024; 11:123. [PMID: 38267456 PMCID: PMC10808109 DOI: 10.1038/s41597-024-02985-y] [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: 09/21/2023] [Accepted: 01/17/2024] [Indexed: 01/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the death of motor neurons, the aetiology of which is essentially unknown. Here, we present an integrative epigenomic study in blood samples from seven clinically characterised sporadic ALS patients to elucidate molecular factors associated with the disease. We used clinical exome sequencing (CES) to study DNA variants, DNA-RNA hybrid immunoprecipitation sequencing (DRIP-seq) to assess R-loop distribution, and reduced representation bisulfite sequencing (RRBS) to examine DNA methylation changes. The above datasets were combined to create a comprehensive repository of genetic and epigenetic changes associated with the ALS cases studied. This repository is well-suited to unveil new correlations within individual patients and across the entire patient cohort. The molecular attributes described here are expected to guide further mechanistic studies on ALS, shedding light on the underlying genetic causes and facilitating the development of new epigenetic therapies to combat this life-threatening disease.
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Affiliation(s)
- Orsolya Feró
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
| | - Dóra Varga
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
- Doctoral School of Pharmaceutical Sciences, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
| | - Éva Nagy
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
| | - Zsolt Karányi
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
- Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, H-4032, Hungary
| | - Éva Sipos
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
| | - József Engelhardt
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Nóra Török
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - István Balogh
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, H-4032, Debrecen, Hungary
| | - Borbála Vető
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, H-4032, Debrecen, Hungary
| | - István Likó
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Ábel Fóthi
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Zoltán Szabó
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, H-4032, Debrecen, Hungary
| | - Gábor Halmos
- Department of Biopharmacy, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary
| | - László Vécsei
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Tamás Arányi
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary.
| | - Lóránt Székvölgyi
- MTA-DE Momentum, Genome Architecture and Recombination Research Group, Department of Molecular and Nanopharmaceutics, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary.
- Doctoral School of Pharmaceutical Sciences, Faculty of Pharmacy, University of Debrecen, H-4032, Debrecen, Hungary.
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, H-4032, Hungary.
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7
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Gabryelska MM, Conn SJ. The RNA interactome in the Hallmarks of Cancer. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1786. [PMID: 37042179 PMCID: PMC10909452 DOI: 10.1002/wrna.1786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/12/2023] [Accepted: 03/20/2023] [Indexed: 04/13/2023]
Abstract
Ribonucleic acid (RNA) molecules are indispensable for cellular homeostasis in healthy and malignant cells. However, the functions of RNA extend well beyond that of a protein-coding template. Rather, both coding and non-coding RNA molecules function through critical interactions with a plethora of cellular molecules, including other RNAs, DNA, and proteins. Deconvoluting this RNA interactome, including the interacting partners, the nature of the interaction, and dynamic changes of these interactions in malignancies has yielded fundamental advances in knowledge and are emerging as a novel therapeutic strategy in cancer. Here, we present an RNA-centric review of recent advances in the field of RNA-RNA, RNA-protein, and RNA-DNA interactomic network analysis and their impact across the Hallmarks of Cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Marta M Gabryelska
- Flinders Health and Medical Research Institute (FHMRI), College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Simon J Conn
- Flinders Health and Medical Research Institute (FHMRI), College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
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8
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Cusan M, Shen H, Zhang B, Liao A, Yang L, Jin M, Fernandez M, Iyer P, Wu Y, Hart K, Gutierrez C, Nik S, Pruett-Miller SM, Stark J, Obeng EA, Bowman TV, Wu CJ, Lin RJ, Wang L. SF3B1 mutation and ATM deletion codrive leukemogenesis via centromeric R-loop dysregulation. J Clin Invest 2023; 133:e163325. [PMID: 37463047 PMCID: PMC10471171 DOI: 10.1172/jci163325] [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: 07/12/2022] [Accepted: 07/12/2023] [Indexed: 09/02/2023] Open
Abstract
RNA splicing factor SF3B1 is recurrently mutated in various cancers, particularly in hematologic malignancies. We previously reported that coexpression of Sf3b1 mutation and Atm deletion in B cells, but not either lesion alone, leads to the onset of chronic lymphocytic leukemia (CLL) with CLL cells harboring chromosome amplification. However, the exact role of Sf3b1 mutation and Atm deletion in chromosomal instability (CIN) remains unclear. Here, we demonstrated that SF3B1 mutation promotes centromeric R-loop (cen-R-loop) accumulation, leading to increased chromosome oscillation, impaired chromosome segregation, altered spindle architecture, and aneuploidy, which could be alleviated by removal of cen-R-loop and exaggerated by deletion of ATM. Aberrant splicing of key genes involved in R-loop processing underlay augmentation of cen-R-loop, as overexpression of the normal isoform, but not the altered form, mitigated mitotic stress in SF3B1-mutant cells. Our study identifies a critical role of splice variants in linking RNA splicing dysregulation and CIN and highlights cen-R-loop augmentation as a key mechanism for leukemogenesis.
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Affiliation(s)
- Martina Cusan
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Haifeng Shen
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Bo Zhang
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
- Department of Hematology, Union Hospital Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Aijun Liao
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
- Department of Hematology, Affiliated Shengjing Hospital of China Medical University, Shenyang, China
| | - Lu Yang
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Meiling Jin
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Mike Fernandez
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Prajish Iyer
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Yiming Wu
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Kevyn Hart
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
| | - Catherine Gutierrez
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Sara Nik
- Gottesman Institute for Stem Cell Biology and Regenerative Medicine and
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, New York, USA
| | - Shondra M. Pruett-Miller
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Jeremy Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Esther A. Obeng
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Teresa V. Bowman
- Gottesman Institute for Stem Cell Biology and Regenerative Medicine and
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, New York, USA
| | - Catherine J. Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Ren-Jang Lin
- Center for RNA Biology and Therapeutics, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Lili Wang
- Department of Systems Biology, Beckman Research Institute of the City of Hope, Monrovia, California, USA
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9
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Pozzi B, Naguleswaran A, Florini F, Rezaei Z, Roditi I. The RNA export factor TbMex67 connects transcription and RNA export in Trypanosoma brucei and sets boundaries for RNA polymerase I. Nucleic Acids Res 2023; 51:5177-5192. [PMID: 37070196 PMCID: PMC10250216 DOI: 10.1093/nar/gkad251] [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: 11/08/2022] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 04/19/2023] Open
Abstract
TbMex67 is the major mRNA export factor known to date in trypanosomes, forming part of the docking platform within the nuclear pore. To explore its role in co-transcriptional mRNA export, recently reported in Trypanosoma brucei, pulse labelling of nascent RNAs with 5-ethynyl uridine (5-EU) was performed with cells depleted of TbMex67 and complemented with a dominant-negative mutant (TbMex67-DN). RNA polymerase (Pol) II transcription was unaffected, but the procyclin loci, which encode mRNAs transcribed by Pol I from internal sites on chromosomes 6 and 10, showed increased levels of 5-EU incorporation. This was due to Pol I readthrough transcription, which proceeded beyond the procyclin and procyclin-associated genes up to the Pol II transcription start site on the opposite strand. Complementation by TbMex67-DN also increased Pol I-dependent formation of R-loops and γ-histone 2A foci. The DN mutant exhibited reduced nuclear localisation and binding to chromatin compared to wild-type TbMex67. Together with its interaction with chromatin remodelling factor TbRRM1 and Pol II, and transcription-dependent association of Pol II with nucleoporins, our findings support a role for TbMex67 in connecting transcription and export in T. brucei. In addition, TbMex67 stalls readthrough by Pol I in specific contexts, thereby limiting R-loop formation and replication stress.
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Affiliation(s)
- Berta Pozzi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | | | | | - Zahra Rezaei
- Professor Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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10
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Saayman X, Graham E, Nathan WJ, Nussenzweig A, Esashi F. Centromeres as universal hotspots of DNA breakage, driving RAD51-mediated recombination during quiescence. Mol Cell 2023; 83:523-538.e7. [PMID: 36702125 PMCID: PMC10009740 DOI: 10.1016/j.molcel.2023.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 10/07/2022] [Accepted: 01/03/2023] [Indexed: 01/27/2023]
Abstract
Centromeres are essential for chromosome segregation in most animals and plants yet are among the most rapidly evolving genome elements. The mechanisms underlying this paradoxical phenomenon remain enigmatic. Here, we report that human centromeres innately harbor a striking enrichment of DNA breaks within functionally active centromere regions. Establishing a single-cell imaging strategy that enables comparative assessment of DNA breaks at repetitive regions, we show that centromeric DNA breaks are induced not only during active cellular proliferation but also de novo during quiescence. Markedly, centromere DNA breaks in quiescent cells are resolved enzymatically by the evolutionarily conserved RAD51 recombinase, which in turn safeguards the specification of functional centromeres. This study highlights the innate fragility of centromeres, which may have been co-opted over time to reinforce centromere specification while driving rapid evolution. The findings also provide insights into how fragile centromeres are likely to contribute to human disease.
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Affiliation(s)
- Xanita Saayman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Emily Graham
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - William J Nathan
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892-4254, USA
| | - Andre Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892-4254, USA
| | - Fumiko Esashi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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11
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Scheuren M, Möhner J, Zischler H. R-loop landscape in mature human sperm: Regulatory and evolutionary implications. Front Genet 2023; 14:1069871. [PMID: 37139234 PMCID: PMC10149866 DOI: 10.3389/fgene.2023.1069871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/03/2023] [Indexed: 05/05/2023] Open
Abstract
R-loops are three-stranded nucleic acid structures consisting of an RNA:DNA hybrid and a displaced DNA strand. While R-loops pose a potential threat to genome integrity, they constitute 5% of the human genome. The role of R-loops in transcriptional regulation, DNA replication, and chromatin signature is becoming increasingly clear. R-loops are associated with various histone modifications, suggesting that they may modulate chromatin accessibility. To potentially harness transcription-coupled repair mechanisms in the germline, nearly the entire genome is expressed during the early stages of male gametogenesis in mammals, providing ample opportunity for the formation of a transcriptome-dependent R-loop landscape in male germ cells. In this study, our data demonstrated the presence of R-loops in fully mature human and bonobo sperm heads and their partial correspondence to transcribed regions and chromatin structure, which is massively reorganized from mainly histone to mainly protamine-packed chromatin in mature sperm. The sperm R-loop landscape resembles characteristic patterns of somatic cells. Surprisingly, we detected R-loops in both residual histone and protamine-packed chromatin and localize them to still-active retroposons, ALUs and SINE-VNTR-ALUs (SVAs), the latter has recently arisen in hominoid primates. We detected both evolutionarily conserved and species-specific localizations. Comparing our DNA-RNA immunoprecipitation (DRIP) data with published DNA methylation and histone chromatin immunoprecipitation (ChIP) data, we hypothesize that R-loops epigenetically reduce methylation of SVAs. Strikingly, we observe a strong influence of R-loops on the transcriptomes of zygotes from early developmental stages before zygotic genome activation. Overall, these findings suggest that chromatin accessibility influenced by R-loops may represent a system of inherited gene regulation.
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12
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Shi X, Teng H, Sun Z. An updated overview of experimental and computational approaches to identify non-canonical DNA/RNA structures with emphasis on G-quadruplexes and R-loops. Brief Bioinform 2022; 23:bbac441. [PMID: 36208174 PMCID: PMC9677470 DOI: 10.1093/bib/bbac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 08/22/2022] [Accepted: 09/13/2022] [Indexed: 12/14/2022] Open
Abstract
Multiple types of non-canonical nucleic acid structures play essential roles in DNA recombination and replication, transcription, and genomic instability and have been associated with several human diseases. Thus, an increasing number of experimental and bioinformatics methods have been developed to identify these structures. To date, most reviews have focused on the features of non-canonical DNA/RNA structure formation, experimental approaches to mapping these structures, and the association of these structures with diseases. In addition, two reviews of computational algorithms for the prediction of non-canonical nucleic acid structures have been published. One of these reviews focused only on computational approaches for G4 detection until 2020. The other mainly summarized the computational tools for predicting cruciform, H-DNA and Z-DNA, in which the algorithms discussed were published before 2012. Since then, several experimental and computational methods have been developed. However, a systematic review including the conformation, sequencing mapping methods and computational prediction strategies for these structures has not yet been published. The purpose of this review is to provide an updated overview of conformation, current sequencing technologies and computational identification methods for non-canonical nucleic acid structures, as well as their strengths and weaknesses. We expect that this review will aid in understanding how these structures are characterised and how they contribute to related biological processes and diseases.
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Affiliation(s)
- Xiaohui Shi
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The first Affiliated Hospital of WMU; Beijing Institutes of Life Science, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Ouhai District, Wenzhou 325000, China
| | - Huajing Teng
- Department of Radiation Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education) at Peking University Cancer Hospital and Institute, Ouhai District, Wenzhou 325000, China
| | - Zhongsheng Sun
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The first Affiliated Hospital of WMU; Beijing Institutes of Life Science, Chinese Academy of Sciences; CAS Center for Excellence in Biotic Interactions and State Key Laboratory of Integrated Management of Pest Insects and Rodents, University of Chinese Academy of Sciences; Institute of Genomic Medicine, Wenzhou Medical University; IBMC-BGI Center, the Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital); Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Ouhai District, Wenzhou 325000, China
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13
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Replication collisions induced by de-repressed S-phase transcription are connected with malignant transformation of adult stem cells. Nat Commun 2022; 13:6907. [PMID: 36376321 PMCID: PMC9663592 DOI: 10.1038/s41467-022-34577-y] [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: 12/02/2021] [Accepted: 10/29/2022] [Indexed: 11/16/2022] Open
Abstract
Transcription replication collisions (TRCs) constitute a major intrinsic source of genome instability but conclusive evidence for a causal role of TRCs in tumor initiation is missing. We discover that lack of the H4K20-dimethyltransferase KMT5B (also known as SUV4-20H1) in muscle stem cells de-represses S-phase transcription by increasing H4K20me1 levels, which induces TRCs and aberrant R-loops in oncogenic genes. The resulting replication stress and aberrant mitosis activate ATR-RPA32-P53 signaling, promoting cellular senescence, which turns into rapid rhabdomyosarcoma formation when p53 is absent. Inhibition of S-phase transcription ameliorates TRCs and formation of R-loops in Kmt5b-deficient MuSCs, validating the crucial role of H4K20me1-dependent, tightly controlled S-phase transcription for preventing collision errors. Low KMT5B expression is prevalent in human sarcomas and associated with tumor recurrence, suggesting a common function of KMT5B in sarcoma formation. The study uncovers decisive functions of KMT5B for maintaining genome stability by repressing S-phase transcription via control of H4K20me1 levels.
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14
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NODULIN HOMEOBOX is required for heterochromatin homeostasis in Arabidopsis. Nat Commun 2022; 13:5058. [PMID: 36030240 PMCID: PMC9420119 DOI: 10.1038/s41467-022-32709-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 08/11/2022] [Indexed: 11/11/2022] Open
Abstract
Arabidopsis NODULIN HOMEOBOX (NDX) is a nuclear protein described as a regulator of specific euchromatic genes within transcriptionally active chromosome arms. Here we show that NDX is primarily a heterochromatin regulator that functions in pericentromeric regions to control siRNA production and non-CG methylation. Most NDX binding sites coincide with pericentromeric het-siRNA loci that mediate transposon silencing, and are antagonistic with R-loop structures that are prevalent in euchromatic chromosomal arms. Inactivation of NDX leads to differential siRNA accumulation and DNA methylation, of which CHH/CHG hypomethylation colocalizes with NDX binding sites. Hi-C analysis shows significant chromatin structural changes in the ndx mutant, with decreased intrachromosomal interactions at pericentromeres where NDX is enriched in wild-type plants, and increased interchromosomal contacts between KNOT-forming regions, similar to those observed in DNA methylation mutants. We conclude that NDX is a key regulator of heterochromatin that is functionally coupled to het-siRNA loci and non-CG DNA methylation pathways. Arabidopsis NDX was previously reported as a regulator of euchromatic gene expression. Here the authors show that NDX functions at pericentromeric regions and regulates heterochromatin homeostasis by controlling siRNA production and non-CG methylation.
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15
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Shih HT, Chen WY, Wang HY, Chao T, Huang HD, Chou CH, Chang ZF. DNMT3b protects centromere integrity by restricting R-loop-mediated DNA damage. Cell Death Dis 2022; 13:546. [PMID: 35688824 PMCID: PMC9187704 DOI: 10.1038/s41419-022-04989-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 01/21/2023]
Abstract
This study used DNA methyltransferase 3b (DNMT3b) knockout cells and the functional loss of DNMT3b mutation in immunodeficiency-centromeric instability-facial anomalies syndrome (ICF) cells to understand how DNMT3b dysfunction causes genome instability. We demonstrated that R-loops contribute to DNA damages in DNMT3b knockout and ICF cells. More prominent DNA damage signal in DNMT3b knockout cells was due to the loss of DNMT3b expression and the acquirement of p53 mutation. Genome-wide ChIP-sequencing mapped DNA damage sites at satellite repetitive DNA sequences including (peri-)centromere regions. However, the steady-state levels of (peri-)centromeric R-loops were reduced in DNMT3b knockout and ICF cells. Our analysis indicates that XPG and XPF endonucleases-mediated cleavages remove (peri-)centromeric R-loops to generate DNA beaks, causing chromosome instability. DNMT3b dysfunctions clearly increase R-loops susceptibility to the cleavage process. Finally, we showed that DNA double-strand breaks (DSBs) in centromere are probably repaired by error-prone end-joining pathway in ICF cells. Thus, DNMT3 dysfunctions undermine the integrity of centromere by R-loop-mediated DNA damages and repair.
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Affiliation(s)
- Hsueh-Tzu Shih
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10051, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Wei-Yi Chen
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
- Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Hsin-Yen Wang
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Tung Chao
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Hsien-Da Huang
- Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Longgang District, 518172, Shenzhen, China
- School of Life and Health Sciences, The Chinese University of Hong Kong, Longgang District, 518172, Shenzhen, China
- School of Medicine, The Chinese University of Hong Kong, Longgang District, 518172, Shenzhen, China
| | - Chih-Hung Chou
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Zee-Fen Chang
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10051, Taiwan.
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.
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16
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Stanek TJ, Cao W, Mehra RM, Ellison CE. Sex-specific variation in R-loop formation in Drosophila melanogaster. PLoS Genet 2022; 18:e1010268. [PMID: 35687614 PMCID: PMC9223372 DOI: 10.1371/journal.pgen.1010268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/23/2022] [Accepted: 05/22/2022] [Indexed: 11/18/2022] Open
Abstract
R-loops are three-stranded nucleotide structures consisting of a DNA:RNA hybrid and a displaced ssDNA non-template strand. Previous work suggests that R-loop formation is primarily determined by the thermodynamics of DNA:RNA binding, which are governed by base composition (e.g., GC skew) and transcription-induced DNA superhelicity. However, R-loops have been described at genomic locations that lack these properties, suggesting that they may serve other context-specific roles. To better understand the genetic determinants of R-loop formation, we have characterized the Drosophila melanogaster R-loop landscape across strains and between sexes using DNA:RNA immunoprecipitation followed by high-throughput sequencing (DRIP-seq). We find that R-loops are associated with sequence motifs that are G-rich or exhibit G/C skew, as well as highly expressed genes, tRNAs, and small nuclear RNAs, consistent with a role for DNA sequence and torsion in R-loop specification. However, we also find motifs associated with R-loops that are A/T-rich and lack G/C skew as well as a subset of R-loops that are enriched in polycomb-repressed chromatin. Differential enrichment analysis reveals a small number of sex-biased R-loops: while non-differentially enriched and male-enriched R-loops form at similar genetic features and chromatin states and contain similar sequence motifs, female-enriched R-loops form at unique genetic features, chromatin states, and sequence motifs and are associated with genes that show ovary-biased expression. Male-enriched R-loops are most abundant on the dosage-compensated X chromosome, where R-loops appear stronger compared to autosomal R-loops. R-loop-containing genes on the X chromosome are dosage-compensated yet show lower MOF binding and reduced H4K16ac compared to R-loop-absent genes, suggesting that H4K16ac or MOF may attenuate R-loop formation. Collectively, these results suggest that R-loop formation in vivo is not fully explained by DNA sequence and topology and raise the possibility that a distinct subset of these hybrid structures plays an important role in the establishment and maintenance of epigenetic differences between sexes.
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Affiliation(s)
- Timothy J. Stanek
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- Department of Pathology, Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Rohan M Mehra
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Christopher E. Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
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17
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Detection of RNA-DNA hybrids by immunostaining in meiotic nuclei of Saccharomyces cerevisiae. STAR Protoc 2022; 3:101325. [PMID: 35479113 PMCID: PMC9035804 DOI: 10.1016/j.xpro.2022.101325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
RNA transcripts can anneal with template DNA strands to form RNA-DNA hybrids (or R-loops if the non-template DNA strands exist), which play a variety of roles in many physiological processes. Here, we provide an accessible and reproducible approach for immunofluorescent staining of RNA-DNA hybrids with the S9.6 antibody in spread meiotic nuclei of Saccharomyces cerevisiae. This protocol allows the examination of RNA-DNA hybrids as clearly distinguishable foci and the colocalizations of RNA-DNA hybrids with other proteins. For complete details on the use and execution of this protocol, please refer to Yang et al. (2021). Protocol for sensitive detection of RNA-DNA hybrids in yeast meiotic nuclei Detailed description of optimized meiotic synchronization and chromosome spread General protocol for detection of RNA-DNA hybrids and interested proteins
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18
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Luo H, Zhu G, Eshelman MA, Fung TK, Lai Q, Wang F, Zeisig BB, Lesperance J, Ma X, Chen S, Cesari N, Cogle C, Chen B, Xu B, Yang FC, So CWE, Qiu Y, Xu M, Huang S. HOTTIP-dependent R-loop formation regulates CTCF boundary activity and TAD integrity in leukemia. Mol Cell 2022; 82:833-851.e11. [PMID: 35180428 PMCID: PMC8985430 DOI: 10.1016/j.molcel.2022.01.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 10/29/2021] [Accepted: 01/19/2022] [Indexed: 01/09/2023]
Abstract
HOTTIP lncRNA is highly expressed in acute myeloid leukemia (AML) driven by MLL rearrangements or NPM1 mutations to mediate HOXA topologically associated domain (TAD) formation and drive aberrant transcription. However, the mechanism through which HOTTIP accesses CCCTC-binding factor (CTCF) chromatin boundaries and regulates CTCF-mediated genome topology remains unknown. Here, we show that HOTTIP directly interacts with and regulates a fraction of CTCF-binding sites (CBSs) in the AML genome by recruiting CTCF/cohesin complex and R-loop-associated regulators to form R-loops. HOTTIP-mediated R-loops reinforce the CTCF boundary and facilitate formation of TADs to drive gene transcription. Either deleting CBS or targeting RNase H to eliminate R-loops in the boundary CBS of β-catenin TAD impaired CTCF boundary activity, inhibited promoter/enhancer interactions, reduced β-catenin target expression, and mitigated leukemogenesis in xenograft mouse models with aberrant HOTTIP expression. Thus, HOTTIP-mediated R-loop formation directly reinforces CTCF chromatin boundary activity and TAD integrity to drive oncogene transcription and leukemia development.
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MESH Headings
- Animals
- CCCTC-Binding Factor/genetics
- CCCTC-Binding Factor/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Line, Tumor
- Chromatin/genetics
- Chromatin/metabolism
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- Gene Expression Regulation, Leukemic
- HEK293 Cells
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice, Transgenic
- R-Loop Structures
- RNA, Long Noncoding/genetics
- RNA, Long Noncoding/metabolism
- Structure-Activity Relationship
- Transcription, Genetic
- Transcriptional Activation
- beta Catenin/genetics
- beta Catenin/metabolism
- Cohesins
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Affiliation(s)
- Huacheng Luo
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Ganqian Zhu
- Department of Molecular Medicine, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA
| | - Melanie A Eshelman
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Tsz Kan Fung
- School of Cancer and Pharmaceutical Science, King's College London, London SE5 9NU, UK; Department of Haematological Medicine, King's College Hospital, London SE5 9RS, UK
| | - Qian Lai
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; Department of Hematology, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Fei Wang
- Department of Hematology and Oncology, The Affiliated Zhongda Hospital, Southeast University Medical School, Nanjing 21009, China
| | - Bernd B Zeisig
- School of Cancer and Pharmaceutical Science, King's College London, London SE5 9NU, UK; Department of Haematological Medicine, King's College Hospital, London SE5 9RS, UK
| | - Julia Lesperance
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Xiaoyan Ma
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; Department of Hematology and Oncology, The Affiliated Zhongda Hospital, Southeast University Medical School, Nanjing 21009, China
| | - Shi Chen
- Department of Molecular Medicine, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA
| | - Nicholas Cesari
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Christopher Cogle
- Division of Hematology/Oncology, Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Baoan Chen
- Department of Hematology and Oncology, The Affiliated Zhongda Hospital, Southeast University Medical School, Nanjing 21009, China
| | - Bing Xu
- Department of Hematology, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Feng-Chun Yang
- Department of Cell System & Anatomy, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA; Mays Cancer Center, Joe R. & Teresa Lozano Long School of Medicine, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA
| | - Chi Wai Eric So
- School of Cancer and Pharmaceutical Science, King's College London, London SE5 9NU, UK; Department of Haematological Medicine, King's College Hospital, London SE5 9RS, UK.
| | - Yi Qiu
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; Penn State Cancer Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
| | - Mingjiang Xu
- Department of Molecular Medicine, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA; Department of Cell System & Anatomy, the University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3904, USA.
| | - Suming Huang
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; Penn State Cancer Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Kannan A, Cuartas J, Gangwani P, Branzei D, Gangwani L. Mutation in senataxin alters the mechanism of R-loop resolution in amyotrophic lateral sclerosis 4. Brain 2022; 145:3072-3094. [PMID: 35045161 PMCID: PMC9536298 DOI: 10.1093/brain/awab464] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/08/2021] [Accepted: 12/03/2021] [Indexed: 11/22/2022] Open
Abstract
Mutation in the senataxin (SETX) gene causes an autosomal dominant neuromuscular disorder, amyotrophic lateral sclerosis 4 (ALS4), characterized by degeneration of motor neurons, muscle weakness and atrophy. SETX is an RNA-DNA helicase that mediates resolution of co-transcriptional RNA:DNA hybrids (R-loops). The process of R-loop resolution is essential for the normal functioning of cells, including neurons. The molecular basis of ALS4 pathogenesis and the mechanism of R-loop resolution are unclear. We report that the zinc finger protein ZPR1 binds to RNA:DNA hybrids, recruits SETX onto R-loops and is critical for R-loop resolution. ZPR1 deficiency disrupts the integrity of R-loop resolution complexes containing SETX and causes increased R-loop accumulation throughout gene transcription. We uncover that SETX is a downstream target of ZPR1 and that overexpression of ZPR1 can rescue R-loop resolution complexe assembly in SETX-deficient cells but not vice versa. To uncover the mechanism of R-loop resolution, we examined the function of SETX-ZPR1 complexes using two genetic motor neuron disease models with altered R-loop resolution. Notably, chronic low levels of SETX-ZPR1 complexes onto R-loops result in a decrease of R-loop resolution activity causing an increase in R-loop levels in spinal muscular atrophy. ZPR1 overexpression increases recruitment of SETX onto R-loops, decreases R-loops and rescues the spinal muscular atrophy phenotype in motor neurons and patient cells. Strikingly, interaction of SETX with ZPR1 is disrupted in ALS4 patients that have heterozygous SETX (L389S) mutation. ZPR1 fails to recruit the mutant SETX homodimer but recruits the heterodimer with partially disrupted interaction between SETX and ZPR1. Interestingly, disruption of SETX-ZPR1 complexes causes increase in R-loop resolution activity leading to fewer R-loops in ALS4. Modulation of ZPR1 levels regulates R-loop accumulation and rescues the pathogenic R-loop phenotype in ALS4 patient cells. These findings originate a new concept, ‘opposite alterations in a cell biological activity (R-loop resolution) result in similar pathogenesis (neurodegeneration) in different genetic motor neuron disorders’. We propose that ZPR1 collaborates with SETX and may function as a molecular brake to regulate SETX-dependent R-loop resolution activity critical for the normal functioning of motor neurons.
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Affiliation(s)
- Annapoorna Kannan
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
| | - Juliana Cuartas
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
| | - Pratik Gangwani
- Automated Driving Compute System Architecture, GM Global Technical Center - Sloan Engineering Center, Warren, Michigan 48092, USA
| | - Dana Branzei
- The FIRC Institute of Molecular Oncology Foundation, IFOM Foundation, Via Adamello 16, Milan 20139, Italy
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
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20
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Lin R, Zhong X, Zhou Y, Geng H, Hu Q, Huang Z, Hu J, Fu XD, Chen L, Chen JY. R-loopBase: a knowledgebase for genome-wide R-loop formation and regulation. Nucleic Acids Res 2021; 50:D303-D315. [PMID: 34792163 PMCID: PMC8728142 DOI: 10.1093/nar/gkab1103] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/28/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
R-loops play versatile roles in many physiological and pathological processes, and are of great interest to scientists in multiple fields. However, controversy about their genomic localization and incomplete understanding of their regulatory network raise great challenges for R-loop research. Here, we present R-loopBase (https://rloopbase.nju.edu.cn) to tackle these pressing issues by systematic integration of genomics and literature data. First, based on 107 high-quality genome-wide R-loop mapping datasets generated by 11 different technologies, we present a reference set of human R-loop zones for high-confidence R-loop localization, and spot conservative genomic features associated with R-loop formation. Second, through literature mining and multi-omics analyses, we curate the most comprehensive list of R-loop regulatory proteins and their targeted R-loops in multiple species to date. These efforts help reveal a global regulatory network of R-loop dynamics and its potential links to the development of cancers and neurological diseases. Finally, we integrate billions of functional genomic annotations, and develop interactive interfaces to search, visualize, download and analyze R-loops and R-loop regulators in a well-annotated genomic context. R-loopBase allows all users, including those with little bioinformatics background to utilize these data for their own research. We anticipate R-loopBase will become a one-stop resource for the R-loop community.
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Affiliation(s)
- Ruoyao Lin
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Xiaoming Zhong
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Yongli Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Huichao Geng
- Hubei Key Laboratory of Cell Homeostasis, RNA Institute, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Qingxi Hu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Zhihao Huang
- Hubei Key Laboratory of Cell Homeostasis, RNA Institute, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Hu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Liang Chen
- Hubei Key Laboratory of Cell Homeostasis, RNA Institute, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jia-Yu Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
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21
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Racca C, Britton S, Hédouin S, Francastel C, Calsou P, Larminat F. BRCA1 prevents R-loop-associated centromeric instability. Cell Death Dis 2021; 12:896. [PMID: 34599155 PMCID: PMC8486751 DOI: 10.1038/s41419-021-04189-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/01/2021] [Accepted: 09/15/2021] [Indexed: 02/05/2023]
Abstract
Centromeres are defined by chromatin containing the histone H3 variant CENP-A assembled onto repetitive α-satellite sequences, which are actively transcribed throughout the cell cycle. Centromeres play an essential role in chromosome inheritance and genome stability through coordinating kinetochores assembly during mitosis. Structural and functional alterations of the centromeres cause aneuploidy and chromosome aberrations which can induce cell death. In human cells, the tumor suppressor BRCA1 associates with centromeric chromatin in the absence of exogenous damage. While we previously reported that BRCA1 contributes to proper centromere homeostasis, the mechanism underlying its centromeric function and recruitment was not fully understood. Here, we show that BRCA1 association with centromeric chromatin depends on the presence of R-loops, which are non-canonical three-stranded structures harboring a DNA:RNA hybrid and are frequently formed during transcription. Subsequently, BRCA1 counteracts the accumulation of R-loops at centromeric α-satellite repeats. Strikingly, BRCA1-deficient cells show impaired localization of CENP-A, higher transcription of centromeric RNA, increased breakage at centromeres and formation of acentric micronuclei, all these features being R-loop-dependent. Finally, BRCA1 depletion reveals a Rad52-dependent hyper-recombination process between centromeric satellite repeats, associated with centromere instability and missegregation. Altogether, our findings provide molecular insights into the key function of BRCA1 in maintaining centromere stability and identity.
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Affiliation(s)
- Carine Racca
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue contre le Cancer, 2018, Toulouse, France
| | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue contre le Cancer, 2018, Toulouse, France
| | - Sabrine Hédouin
- Université de Paris, Epigénétique et Destin Cellulaire, CNRS, Paris, F-75013, France.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Claire Francastel
- Université de Paris, Epigénétique et Destin Cellulaire, CNRS, Paris, F-75013, France
| | - Patrick Calsou
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.,Equipe Labellisée Ligue contre le Cancer, 2018, Toulouse, France
| | - Florence Larminat
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France. .,Equipe Labellisée Ligue contre le Cancer, 2018, Toulouse, France.
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22
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Gao J, Zhang P, Li X, Wu W, Wei H, Zhang W. Toward an understanding of the detection and function of R-loops in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6110-6122. [PMID: 34115858 DOI: 10.1093/jxb/erab280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/10/2021] [Indexed: 06/12/2023]
Abstract
Although lagging behind studies in humans and other mammals, studies of R-loops in plants have recently entered an exciting stage in which the roles of R-loops in gene expression, genome stability, epigenomic signatures, and plant development and stress responses are being elucidated. Here, we review the strengths and weaknesses of existing methodologies, which were largely developed for R-loop studies in mammals, and then discuss the potential challenges of applying these methodologies to R-loop studies in plants. We then focus on recent advances in the functional characterization of R-loops in Arabidopsis thaliana and rice. Recent studies in plants indicate that there are coordinated relationships between R-loops and gene expression, and between R-loops and epigenomic signatures that depend, in part, on the types of R-loops involved. Finally, we discuss the emerging roles of R-loops in plants and directions for future research.
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Affiliation(s)
- Jingjing Gao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Pengyue Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Xinxu Li
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
| | - Wenqi Wu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Hairong Wei
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA
| | - Wenli Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, China
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23
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Wu T, Nance J, Chu F, Fazzio TG. Characterization of R-Loop-Interacting Proteins in Embryonic Stem Cells Reveals Roles in rRNA Processing and Gene Expression. Mol Cell Proteomics 2021; 20:100142. [PMID: 34478875 PMCID: PMC8461376 DOI: 10.1016/j.mcpro.2021.100142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 08/21/2021] [Accepted: 08/25/2021] [Indexed: 12/14/2022] Open
Abstract
Chromatin-associated RNAs have diverse roles in the nucleus. However, their mechanisms of action are poorly understood, in part because of the inability to identify proteins that specifically associate with chromatin-bound RNAs. Here, we address this problem for a subset of chromatin-associated RNAs that form R-loops-RNA-DNA hybrid structures that include a displaced strand of ssDNA. R-loops generally form cotranscriptionally and have important roles in regulation of gene expression, immunoglobulin class switching, and other processes. However, unresolved R-loops can lead to DNA damage and chromosome instability. To identify factors that may bind and regulate R-loop accumulation or mediate R-loop-dependent functions, we used a comparative immunoprecipitation/MS approach, with and without RNA-protein crosslinking, to identify a stringent set of R-loop-binding proteins in mouse embryonic stem cells. We identified 364 R-loop-interacting proteins, which were highly enriched for proteins with predicted RNA-binding functions. We characterized several R-loop-interacting proteins of the DEAD-box family of RNA helicases and found that these proteins localize to the nucleolus and, to a lesser degree, the nucleus. Consistent with their localization patterns, we found that these helicases are required for rRNA processing and regulation of gene expression. Surprisingly, depletion of these helicases resulted in misregulation of highly overlapping sets of protein-coding genes, including many genes that function in differentiation and development. We conclude that R-loop-interacting DEAD-box helicases have nonredundant roles that are critical for maintaining the normal embryonic stem cell transcriptome.
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Affiliation(s)
- Tong Wu
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jennifer Nance
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Feixia Chu
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Thomas G Fazzio
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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24
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Ellis DA, Reyes-Martín F, Rodríguez-López M, Cotobal C, Sun XM, Saintain Q, Jeffares DC, Marguerat S, Tallada VA, Bähler J. R-loops and regulatory changes in chronologically ageing fission yeast cells drive non-random patterns of genome rearrangements. PLoS Genet 2021; 17:e1009784. [PMID: 34464389 PMCID: PMC8437301 DOI: 10.1371/journal.pgen.1009784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 09/13/2021] [Accepted: 08/18/2021] [Indexed: 12/03/2022] Open
Abstract
Aberrant repair of DNA double-strand breaks can recombine distant chromosomal breakpoints. Chromosomal rearrangements compromise genome function and are a hallmark of ageing. Rearrangements are challenging to detect in non-dividing cell populations, because they reflect individually rare, heterogeneous events. The genomic distribution of de novo rearrangements in non-dividing cells, and their dynamics during ageing, remain therefore poorly characterized. Studies of genomic instability during ageing have focussed on mitochondrial DNA, small genetic variants, or proliferating cells. To characterize genome rearrangements during cellular ageing in non-dividing cells, we interrogated a single diagnostic measure, DNA breakpoint junctions, using Schizosaccharomyces pombe as a model system. Aberrant DNA junctions that accumulated with age were associated with microhomology sequences and R-loops. Global hotspots for age-associated breakpoint formation were evident near telomeric genes and linked to remote breakpoints elsewhere in the genome, including the mitochondrial chromosome. Formation of breakpoint junctions at global hotspots was inhibited by the Sir2 histone deacetylase and might be triggered by an age-dependent de-repression of chromatin silencing. An unexpected mechanism of genomic instability may cause more local hotspots: age-associated reduction in an RNA-binding protein triggering R-loops at target loci. This result suggests that biological processes other than transcription or replication can drive genome rearrangements. Notably, we detected similar signatures of genome rearrangements that accumulated in old brain cells of humans. These findings provide insights into the unique patterns and possible mechanisms of genome rearrangements in non-dividing cells, which can be promoted by ageing-related changes in gene-regulatory proteins.
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Affiliation(s)
- David A. Ellis
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Félix Reyes-Martín
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - María Rodríguez-López
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Cristina Cotobal
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Xi-Ming Sun
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Quentin Saintain
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Daniel C. Jeffares
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Samuel Marguerat
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Víctor A. Tallada
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Jürg Bähler
- Institute of Healthy Ageing, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
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25
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Binzel DW, Li X, Burns N, Khan E, Lee WJ, Chen LC, Ellipilli S, Miles W, Ho YS, Guo P. Thermostability, Tunability, and Tenacity of RNA as Rubbery Anionic Polymeric Materials in Nanotechnology and Nanomedicine-Specific Cancer Targeting with Undetectable Toxicity. Chem Rev 2021; 121:7398-7467. [PMID: 34038115 PMCID: PMC8312718 DOI: 10.1021/acs.chemrev.1c00009] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA nanotechnology is the bottom-up self-assembly of nanometer-scale architectures, resembling LEGOs, composed mainly of RNA. The ideal building material should be (1) versatile and controllable in shape and stoichiometry, (2) spontaneously self-assemble, and (3) thermodynamically, chemically, and enzymatically stable with a long shelf life. RNA building blocks exhibit each of the above. RNA is a polynucleic acid, making it a polymer, and its negative-charge prevents nonspecific binding to negatively charged cell membranes. The thermostability makes it suitable for logic gates, resistive memory, sensor set-ups, and NEM devices. RNA can be designed and manipulated with a level of simplicity of DNA while displaying versatile structure and enzyme activity of proteins. RNA can fold into single-stranded loops or bulges to serve as mounting dovetails for intermolecular or domain interactions without external linking dowels. RNA nanoparticles display rubber- and amoeba-like properties and are stretchable and shrinkable through multiple repeats, leading to enhanced tumor targeting and fast renal excretion to reduce toxicities. It was predicted in 2014 that RNA would be the third milestone in pharmaceutical drug development. The recent approval of several RNA drugs and COVID-19 mRNA vaccines by FDA suggests that this milestone is being realized. Here, we review the unique properties of RNA nanotechnology, summarize its recent advancements, describe its distinct attributes inside or outside the body and discuss potential applications in nanotechnology, medicine, and material science.
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Affiliation(s)
- Daniel W Binzel
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xin Li
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Nicolas Burns
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Eshan Khan
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, College of Medicine, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wen-Jui Lee
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Li-Ching Chen
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Satheesh Ellipilli
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wayne Miles
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, College of Medicine, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yuan Soon Ho
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
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26
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Ngo GHP, Grimstead JW, Baird DM. UPF1 promotes the formation of R loops to stimulate DNA double-strand break repair. Nat Commun 2021; 12:3849. [PMID: 34158508 PMCID: PMC8219777 DOI: 10.1038/s41467-021-24201-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 06/07/2021] [Indexed: 12/12/2022] Open
Abstract
DNA-RNA hybrid structures have been detected at the vicinity of DNA double-strand breaks (DSBs) occurring within transcriptional active regions of the genome. The induction of DNA-RNA hybrids strongly affects the repair of these DSBs, but the nature of these structures and how they are formed remain poorly understood. Here we provide evidence that R loops, three-stranded structures containing DNA-RNA hybrids and the displaced single-stranded DNA (ssDNA) can form at sub-telomeric DSBs. These R loops are generated independently of DNA resection but are induced alongside two-stranded DNA-RNA hybrids that form on ssDNA generated by DNA resection. We further identified UPF1, an RNA/DNA helicase, as a crucial factor that drives the formation of these R loops and DNA-RNA hybrids to stimulate DNA resection, homologous recombination, microhomology-mediated end joining and DNA damage checkpoint activation. Our data show that R loops and DNA-RNA hybrids are actively generated at DSBs to facilitate DNA repair.
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Affiliation(s)
- Greg H P Ngo
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Julia W Grimstead
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Duncan M Baird
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK.
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27
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Pinter S, Knodel F, Choudalakis M, Schnee P, Kroll C, Fuchs M, Broehm A, Weirich S, Roth M, Eisler SA, Zuber J, Jeltsch A, Rathert P. A functional LSD1 coregulator screen reveals a novel transcriptional regulatory cascade connecting R-loop homeostasis with epigenetic regulation. Nucleic Acids Res 2021; 49:4350-4370. [PMID: 33823549 PMCID: PMC8096265 DOI: 10.1093/nar/gkab180] [Citation(s) in RCA: 3] [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: 02/12/2021] [Accepted: 03/04/2021] [Indexed: 12/30/2022] Open
Abstract
The lysine specific demethylase 1 (LSD1) plays a pivotal role in cellular differentiation by regulating the expression of key developmental genes in concert with different coregulatory proteins. This process is impaired in different cancer types and incompletely understood. To comprehensively identify functional coregulators of LSD1, we established a novel tractable fluorescent reporter system to monitor LSD1 activity in living cells. Combining this reporter system with a state-of-the-art multiplexed RNAi screen, we identify the DEAD-box helicase 19A (DDX19A) as a novel coregulator and demonstrate that suppression of Ddx19a results in an increase of R-loops and reduced LSD1-mediated gene silencing. We further show that DDX19A binds to tri-methylated lysine 27 of histone 3 (H3K27me3) and it regulates gene expression through the removal of transcription promoting R-loops. Our results uncover a novel transcriptional regulatory cascade where the downregulation of genes is dependent on the LSD1 mediated demethylation of histone H3 lysine 4 (H3K4). This allows the polycomb repressive complex 2 (PRC2) to methylate H3K27, which serves as a binding site for DDX19A. Finally, the binding of DDX19A leads to the efficient removal of R-loops at active promoters, which further de-represses LSD1 and PRC2, establishing a positive feedback loop leading to a robust repression of the target gene.
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Affiliation(s)
- Sabine Pinter
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Franziska Knodel
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Michel Choudalakis
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Philipp Schnee
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Carolin Kroll
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Marina Fuchs
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Alexander Broehm
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Sara Weirich
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Mareike Roth
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Stephan A Eisler
- Stuttgart Research Center Systems Biology (SRCSB), University of Stuttgart, 70569 Stuttgart, Germany
| | - Johannes Zuber
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria
| | - Albert Jeltsch
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Philipp Rathert
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany
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28
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Friedman Y, Hizi A, Avni D, Bakhanashvili M. Mitochondrial matrix-localized p53 participates in degradation of mitochondrial RNAs. Mitochondrion 2021; 58:200-212. [PMID: 33775872 DOI: 10.1016/j.mito.2021.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/11/2021] [Accepted: 03/22/2021] [Indexed: 11/18/2022]
Abstract
Mitochondrial RNA degradation plays an important role in maintenance of the mitochondria genetic integrity. Mitochondrial localization of p53 was observed in non-stressed and stressed cells. p53, as an RNA-binding protein, exerts 3'→5' exoribonuclease activity. The data suggest that in non-stressed cells, mitochondrial matrix-localized p53, with exoribonuclease activity, may play a housekeeping positive role. p53, through restriction the formation of new RNA/DNA hybrid and processing R-loop, might serve as mitochondrial R-loop suppressor. Conversely, stress-induced matrix-p53 decreases the amount of mitochondrial single-stranded RNA transcripts (including polyA- and non-polyA RNAs), thereby leading to the decline in the amount of mitochondria-encoded oxidative phosphorylation components.
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Affiliation(s)
- Yael Friedman
- Infectious Diseases Unit, Sheba Medical Center, Tel-Hashomer 5265601, Israel
| | - Amnon Hizi
- Department of Cellular and Developmental Biology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Dror Avni
- Lab. Mol. Cell Biology, Center for Cancer Research & Dep. of Medicine C, Sheba Medical Center, Tel Hashomer, Israel
| | - Mary Bakhanashvili
- Infectious Diseases Unit, Sheba Medical Center, Tel-Hashomer 5265601, Israel; The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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29
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Wang K, Wang H, Li C, Yin Z, Xiao R, Li Q, Xiang Y, Wang W, Huang J, Chen L, Fang P, Liang K. Genomic profiling of native R loops with a DNA-RNA hybrid recognition sensor. SCIENCE ADVANCES 2021; 7:7/8/eabe3516. [PMID: 33597247 PMCID: PMC7888926 DOI: 10.1126/sciadv.abe3516] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/30/2020] [Indexed: 05/08/2023]
Abstract
An R loop is a unique triple-stranded structure that participates in multiple key biological processes and is relevant to human diseases. Accurate and comprehensive R loop profiling is a prerequisite for R loops studies. However, current R loop mapping methods generate large discrepancies, therefore an independent method is in urgent need. Here, we establish an independent R loop CUT&Tag (Tn5-based cleavage under targets and tagmentation) method by combining CUT&Tag and GST-His6-2×HBD (glutathione S-transferase-hexahistidine-2× hybrid-binding domain), an artificial DNA-RNA hybrid sensor that specifically recognizes the DNA-RNA hybrids. We demonstrate that the R loop CUT&Tag is sensitive, reproducible, and convenient for native R loop mapping with high resolution, and find that the capture strategies, instead of the specificity of sensors, largely contribute to the disparities among different methods. Together, we provide an independent strategy for genomic profiling of native R loops and help resolve discrepancies among multiple R loop mapping methods.
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Affiliation(s)
- Kang Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Honghong Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Conghui Li
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Zhinang Yin
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Ruijing Xiao
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
- Department of Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Qiuzi Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, P.R. China
| | - Ying Xiang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Wen Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jian Huang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, P.R. China
| | - Liang Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, P.R. China
| | - Pingping Fang
- Department of Pharmacology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
| | - Kaiwei Liang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
- Hubei Province Key Laboratory of Allergy and Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
- Research Center for Medicine and Structural Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
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30
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Saha S, Sun Y, Huang SYN, Baechler SA, Pongor LS, Agama K, Jo U, Zhang H, Tse-Dinh YC, Pommier Y. DNA and RNA Cleavage Complexes and Repair Pathway for TOP3B RNA- and DNA-Protein Crosslinks. Cell Rep 2020; 33:108569. [PMID: 33378676 PMCID: PMC7859927 DOI: 10.1016/j.celrep.2020.108569] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 11/20/2020] [Accepted: 12/07/2020] [Indexed: 12/31/2022] Open
Abstract
The present study demonstrates that topoisomerase 3B (TOP3B) forms both RNA and DNA cleavage complexes (TOP3Bccs) in vivo and reveals a pathway for repairing TOP3Bccs. For inducing and detecting cellular TOP3Bccs, we engineer a “self-trapping” mutant of TOP3B (R338W-TOP3B). Transfection with R338W-TOP3B induces R-loops, genomic damage, and growth defect, which highlights the importance of TOP3Bcc repair mechanisms. To determine how cells repair TOP3Bccs, we deplete tyrosyl-DNA phosphodiesterases (TDP1 and TDP2). TDP2-deficient cells show elevated TOP3Bccs both in DNA and RNA. Conversely, overexpression of TDP2 lowers cellular TOP3Bccs. Using recombinant human TDP2, we demonstrate that TDP2 can process both denatured and proteolyzed TOP3Bccs. We also show that cellular TOP3Bccs are ubiquitinated by the E3 ligase TRIM41 before undergoing proteasomal processing and excision by TDP2. Saha et al. introduce an approach to generate and detect the catalytic intermediates of TOP3B in DNA and RNA by engineering a self-poisoning enzyme, R338W-TOP3B. They reveal the cellular consequences of abortive TOP3Bcc formation and a repair pathway involving TRIM41, the proteasome, and TDP2 for processing of TOP3Bcc.
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Affiliation(s)
- Sourav Saha
- 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
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Simone Andrea Baechler
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Lorinc Sandor Pongor
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Keli Agama
- 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
| | - Hongliang Zhang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Yuk-Ching Tse-Dinh
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA; Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, 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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Detection of Telomeric DNA:RNA Hybrids Using TeloDRIP-qPCR. Int J Mol Sci 2020; 21:ijms21249774. [PMID: 33371452 PMCID: PMC7767442 DOI: 10.3390/ijms21249774] [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: 11/30/2020] [Accepted: 12/17/2020] [Indexed: 11/17/2022] Open
Abstract
Because of their intrinsic characteristics, telomeres are genomic loci that pose significant problems during the replication of the genome. In particular, it has been observed that telomeres that are maintained in cancer cells by the alternative mechanism of the lengthening of telomeres (ALT) harbor higher levels of replicative stress compared with telomerase-positive cancer cells. R-loops are three-stranded structures formed by a DNA:RNA hybrid and a displaced ssDNA. Emerging evidence suggests that controlling the levels of R-loops at ALT telomeres is critical for telomere maintenance. In fact, on the one hand, they favor telomere recombination, but on the other, they are a source of detrimental replicative stress. DRIP (DNA:RNA immunoprecipitation) is the main technique used for the detection of R-loops, and it is based on the use of the S9.6 antibody, which recognizes preferentially DNA:RNA hybrids in a sequence-independent manner. The detection of DNA:RNA hybrids in repetitive sequences such as telomeres requires some additional precautions as a result of their repetitive nature. Here, we share an optimized protocol for the detection of telomeric DNA:RNA hybrids, and we demonstrate its application in an ALT and in a telomerase-positive cell line. We demonstrate that ALT telomeres bear higher levels of DNA:RNA hybrids, and we propose this method as a reliable way to detect them in telomeres.
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Giannini M, Bayona-Feliu A, Sproviero D, Barroso SI, Cereda C, Aguilera A. TDP-43 mutations link Amyotrophic Lateral Sclerosis with R-loop homeostasis and R loop-mediated DNA damage. PLoS Genet 2020; 16:e1009260. [PMID: 33301444 PMCID: PMC7755276 DOI: 10.1371/journal.pgen.1009260] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 12/22/2020] [Accepted: 11/08/2020] [Indexed: 12/16/2022] Open
Abstract
TDP-43 is a DNA and RNA binding protein involved in RNA processing and with structural resemblance to heterogeneous ribonucleoproteins (hnRNPs), whose depletion sensitizes neurons to double strand DNA breaks (DSBs). Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder, in which 97% of patients are familial and sporadic cases associated with TDP-43 proteinopathies and conditions clearing TDP-43 from the nucleus, but we know little about the molecular basis of the disease. After showing with the non-neuronal model of HeLa cells that TDP-43 depletion increases R loops and associated genome instability, we prove that mislocalization of mutated TDP-43 (A382T) in transfected neuronal SH-SY5Y and lymphoblastoid cell lines (LCLs) from an ALS patient cause R-loop accumulation, R loop-dependent increased DSBs and Fanconi Anemia repair centers. These results uncover a new role of TDP-43 in the control of co-transcriptional R loops and the maintenance of genome integrity by preventing harmful R-loop accumulation. Our findings thus link TDP-43 pathology to increased R loops and R loop-mediated DNA damage opening the possibility that R-loop modulation in TDP-43-defective cells might help develop ALS therapies. Amyotrophic Lateral Sclerosis (ALS) is an adult onset, progressive neurodegenerative disease, caused by the selective loss of upper and lower motor neurons in the cerebral cortex, brainstem and spinal cord. The nuclear TDP-43 RNA binding protein, is encoded by a major gene for ALS susceptibility whose mutations are found in 3% of familial and 2% of sporadic ALS cases. Thanks to its ability to recognize DNA and RNA, TDP-43 is involved in different steps of mRNA metabolism and in several mechanisms of genome integrity. This, together with the fact that R loops or DNA-RNA hybrids are a common source of genome instability, prompted us to investigate whether TDP-43 deficiency has any role in R loop homeostasis that could explain previously described DNA damage response defects of ALS cells. We show that TDP-43 plays a role in preventing R loop-accumulation and associated genome instability in neuronal and non-neuronal cells, as well as in patient cell lines. Thus, our study opens the possibility that R loop-modulation in TDP-43-defective cells might help develop ALS therapies.
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Affiliation(s)
- Marta Giannini
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Aleix Bayona-Feliu
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Daisy Sproviero
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Sonia I. Barroso
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Cristina Cereda
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
- * E-mail: (CC); (AA)
| | - Andrés Aguilera
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- * E-mail: (CC); (AA)
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Crossley MP, Bocek MJ, Hamperl S, Swigut T, Cimprich KA. qDRIP: a method to quantitatively assess RNA-DNA hybrid formation genome-wide. Nucleic Acids Res 2020; 48:e84. [PMID: 32544226 PMCID: PMC7641308 DOI: 10.1093/nar/gkaa500] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 05/30/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022] Open
Abstract
R-loops are dynamic, co-transcriptional nucleic acid structures that facilitate physiological processes but can also cause DNA damage in certain contexts. Perturbations of transcription or R-loop resolution are expected to change their genomic distribution. Next-generation sequencing approaches to map RNA–DNA hybrids, a component of R-loops, have so far not allowed quantitative comparisons between such conditions. Here, we describe quantitative differential DNA–RNA immunoprecipitation (qDRIP), a method combining synthetic RNA–DNA-hybrid internal standards with high-resolution, strand-specific sequencing. We show that qDRIP avoids biases inherent to read-count normalization by accurately profiling signal in regions unaffected by transcription inhibition in human cells, and by facilitating accurate differential peak calling between conditions. We also use these quantitative comparisons to make the first estimates of the absolute count of RNA–DNA hybrids per cell and their half-lives genome-wide. Finally, we identify a subset of RNA–DNA hybrids with high GC skew which are partially resistant to RNase H. Overall, qDRIP allows for accurate normalization in conditions where R-loops are perturbed and for quantitative measurements that provide previously unattainable biological insights.
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Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stephan Hamperl
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Dou P, Li Y, Sun H, Xie W, Zhang X, Zhang X, Zhang D, Qiao S, Ci Y, Nie H, Han F, Li Y. C1orf109L binding DHX9 promotes DNA damage depended on the R-loop accumulation and enhances camptothecin chemosensitivity. Cell Prolif 2020; 53:e12875. [PMID: 32761833 PMCID: PMC7507383 DOI: 10.1111/cpr.12875] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/14/2020] [Accepted: 06/17/2020] [Indexed: 12/15/2022] Open
Abstract
Objectives R‐loop is a three‐stranded nucleic acid structure of RNA/DNA hybrid, which occurs naturally during transcription, and more R‐loop accumulation can trigger serious DNA damage. There has been increasing attention to the issue of R‐loop accumulation acted as a target for cancer therapy. However, the regulation of R‐loop‐associated proteins is poorly explored. Material and method Quantitative real‐time PCR and Western blot were used to measure the expression of C1orf109 in cell lines. In addition, C1orf109L (C1orf109 longest isoform) protein binding partner was identified and validated using immunoprecipitation‐mass spectrometric (IP‐MS) and immunoprecipitation assays. DNA‐RNA immunoprecipitation (DR‐IP) and immunofluorescence determined the C1orf109L location on R‐loop. R‐loop accumulation was determined by immunofluorescence. Cell cycle was determined by flow cytometry. Finally, time‐lapse assay and cell counting were conducted to determined cell survival in response to camptothecin (CPT). Results We found that C1orf109L could mediate cell cycle arrest in the G2/M phase and DNA damage depended on R‐loop accumulation. Meanwhile, C1orf109L could bind with DHX9 to trigger R‐loop accumulation. And C1orf109L was competitive with PARP1 binding to DHX9, which would block the function of DHX9‐PARP1 to prevent the R‐loop accumulation. Furthermore, C1orf109L could enhance the chemosensitivity of CPT, a chemotherapeutic drug capable of promoting R‐loop formation. Conclusions Our data demonstrate that C1orf109L triggers R‐loop accumulation and DNA damage to arrest cell cycle.
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Affiliation(s)
- Peng Dou
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Yiqun Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Haoxiu Sun
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Wanqiu Xie
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Xiaoqing Zhang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Xiaohan Zhang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Dandan Zhang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Shupei Qiao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Yanpeng Ci
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Huan Nie
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Fang Han
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
| | - Yu Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin City, China
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New insight into the biology of R-loops. Mutat Res 2020; 821:111711. [PMID: 32516653 DOI: 10.1016/j.mrfmmm.2020.111711] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 11/24/2022]
Abstract
R-loops form when RNA hybridizes with its template DNA generating a three-stranded structure leaving a displaced single strand non-template DNA. During transcription negative supercoiling of DNA behind the advancing RNA polymerase will facilitate the formation of R-loops by the nascent RNA as the DNA is under wound to facilitate transcription. In theory R-loops are classified into pathological and non-pathological depending on the context of its formation. R-loop which are formed normally in various physiological events like in gene regulation and at immunoglobulin class switch regions are considered non-pathological, whereas abnormally stable R-loop which leads to genomic instability are considered pathological. Although pathological R-loop formation is a rare event but once formed completely blocks transcription, mRNA export, elevates mutagenesis, and inhibits gene expression. Hence, R-loop either prevents or induces genomic instability indirectly and are potentially an endogenous source of DNA lesion. Although the existence of R-loop has been reported few decades ago, but only recently we have gained knowledge about its formation and resolution in cells due to the availability of reagents. R-loop biology has generated immense interest in past few years since it connects the important biological processes such as transcription, mRNA splicing, DNA replication, recombination and repair. In this review I will focus on the recent progress made about formation and resolution of R-loop, based on the methodologies that are currently available to study R-loop using biochemical, cell biology and molecular biology approaches.
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R-loop-forming Sequences Analysis in Thousands of Viral Genomes Identify A New Common Element in Herpesviruses. Sci Rep 2020; 10:6389. [PMID: 32286400 PMCID: PMC7156643 DOI: 10.1038/s41598-020-63101-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/20/2020] [Indexed: 11/16/2022] Open
Abstract
R-loops are RNA-DNA hybrid sequences that are emerging players in various biological processes, occurring in both prokaryotic and eukaryotic cells. In viruses, R-loop investigation is limited and functional importance is poorly understood. Here, we performed a computational approach to investigate prevalence, distribution, and location of R-loop forming sequences (RLFS) across more than 6000 viral genomes. A total of 14637 RLFS loci were identified in 1586 viral genomes. Over 70% of RLFS-positive genomes are dsDNA viruses. In the order Herpesvirales, RLFS were presented in all members whereas no RLFS was predicted in the order Ligamenvirales. Analysis of RLFS density in all RLFS-positive genomes revealed unusually high RLFS densities in herpesvirus genomes, with RLFS densities particularly enriched within repeat regions such as the terminal repeats (TRs). RLFS in TRs are positionally conserved between herpesviruses. Validating the computationally-identified RLFS, R-loop formation was experimentally confirmed in the TR and viral Bcl-2 promoter of Kaposi sarcoma-associated herpesvirus (KSHV). These predictions and validations support future analysis of RLFS in regulating the replication, transcription, and genome maintenance of herpesviruses.
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Nava GM, Grasso L, Sertic S, Pellicioli A, Muzi Falconi M, Lazzaro F. One, No One, and One Hundred Thousand: The Many Forms of Ribonucleotides in DNA. Int J Mol Sci 2020; 21:E1706. [PMID: 32131532 PMCID: PMC7084774 DOI: 10.3390/ijms21051706] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 12/14/2022] Open
Abstract
In the last decade, it has become evident that RNA is frequently found in DNA. It is now well established that single embedded ribonucleoside monophosphates (rNMPs) are primarily introduced by DNA polymerases and that longer stretches of RNA can anneal to DNA, generating RNA:DNA hybrids. Among them, the most studied are R-loops, peculiar three-stranded nucleic acid structures formed upon the re-hybridization of a transcript to its template DNA. In addition, polyribonucleotide chains are synthesized to allow DNA replication priming, double-strand breaks repair, and may as well result from the direct incorporation of consecutive rNMPs by DNA polymerases. The bright side of RNA into DNA is that it contributes to regulating different physiological functions. The dark side, however, is that persistent RNA compromises genome integrity and genome stability. For these reasons, the characterization of all these structures has been under growing investigation. In this review, we discussed the origin of single and multiple ribonucleotides in the genome and in the DNA of organelles, focusing on situations where the aberrant processing of RNA:DNA hybrids may result in multiple rNMPs embedded in DNA. We concluded by providing an overview of the currently available strategies to study the presence of single and multiple ribonucleotides in DNA in vivo.
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Affiliation(s)
| | | | | | | | - Marco Muzi Falconi
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy; (G.M.N.); (L.G.); (S.S.); (A.P.)
| | - Federico Lazzaro
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy; (G.M.N.); (L.G.); (S.S.); (A.P.)
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Brambati A, Zardoni L, Nardini E, Pellicioli A, Liberi G. The dark side of RNA:DNA hybrids. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 784:108300. [PMID: 32430097 DOI: 10.1016/j.mrrev.2020.108300] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/07/2020] [Accepted: 02/23/2020] [Indexed: 12/15/2022]
Abstract
RNA:DNA hybrids form when nascent transcripts anneal to the DNA template strand or any homologous DNA region. Co-transcriptional RNA:DNA hybrids, organized in R-loop structures together with the displaced non-transcribed strand, assist gene expression, DNA repair and other physiological cellular functions. A dark side of the matter is that RNA:DNA hybrids are also a cause of DNA damage and human diseases. In this review, we summarize recent advances in the understanding of the mechanisms by which the impairment of hybrid turnover promotes DNA damage and genome instability via the interference with DNA replication and DNA double-strand break repair. We also discuss how hybrids could contribute to cancer, neurodegeneration and susceptibility to viral infections, focusing on dysfunctions associated with the anti-R-loop helicase Senataxin.
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Affiliation(s)
- Alessandra Brambati
- Istituto di Genetica Molecolare Luigi Luca Cavalli-Sforza, CNR, Via Abbiategrasso 207, 27100, Pavia, Italy.
| | - Luca Zardoni
- Istituto di Genetica Molecolare Luigi Luca Cavalli-Sforza, CNR, Via Abbiategrasso 207, 27100, Pavia, Italy; Scuola Universitaria Superiore, IUSS, 27100, Pavia, Italy
| | - Eleonora Nardini
- Istituto di Genetica Molecolare Luigi Luca Cavalli-Sforza, CNR, Via Abbiategrasso 207, 27100, Pavia, Italy
| | - Achille Pellicioli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Giordano Liberi
- Istituto di Genetica Molecolare Luigi Luca Cavalli-Sforza, CNR, Via Abbiategrasso 207, 27100, Pavia, Italy; IFOM Foundation, Via Adamello 16, 20139, Milan, Italy.
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Abstract
Formation of DNA:RNA hybrids or R-loops contributes to numerous biologic processes. The development of the S9.6 antibody makes the analysis of R-Loops (DNA:RNA hybrids) possible through immunoprecipitation. Here, we describe the isolation of DNA:RNA hybrid structures using the S9.6 antibody. Using this protocol, both the DNA and RNA binding partners of the R-loop can be analyzed via qPCR, whole genome sequencing, or other methods.
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Affiliation(s)
| | - Thomas M Aune
- Vanderbilt University Medical Center, Nashville, TN, USA.
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40
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Drugging the R-loop interactome: RNA-DNA hybrid binding proteins as targets for cancer therapy. DNA Repair (Amst) 2019; 84:102642. [DOI: 10.1016/j.dnarep.2019.102642] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/16/2019] [Accepted: 07/02/2019] [Indexed: 02/07/2023]
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41
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R Loops: From Physiological to Pathological Roles. Cell 2019; 179:604-618. [PMID: 31607512 DOI: 10.1016/j.cell.2019.08.055] [Citation(s) in RCA: 364] [Impact Index Per Article: 72.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/19/2019] [Accepted: 08/28/2019] [Indexed: 12/13/2022]
Abstract
DNA-RNA hybrids play a physiological role in cellular processes, but often, they represent non-scheduled co-transcriptional structures with a negative impact on transcription, replication and DNA repair. Accumulating evidence suggests that they constitute a source of replication stress, DNA breaks and genome instability. Reciprocally, DNA breaks facilitate DNA-RNA hybrid formation by releasing the double helix torsional conformation. Cells avoid DNA-RNA accumulation by either preventing or removing hybrids directly or by DNA repair-coupled mechanisms. Given the R-loop impact on chromatin and genome organization and its potential relation with genetic diseases, we review R-loop homeostasis as well as their physiological and pathological roles.
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Chang EYC, Tsai S, Aristizabal MJ, Wells JP, Coulombe Y, Busatto FF, Chan YA, Kumar A, Dan Zhu Y, Wang AYH, Fournier LA, Hieter P, Kobor MS, Masson JY, Stirling PC. MRE11-RAD50-NBS1 promotes Fanconi Anemia R-loop suppression at transcription-replication conflicts. Nat Commun 2019; 10:4265. [PMID: 31537797 PMCID: PMC6753070 DOI: 10.1038/s41467-019-12271-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 08/30/2019] [Indexed: 12/25/2022] Open
Abstract
Ectopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors including the MRE11-RAD50-NBS1 (MRN) complex. While MRN has been shown to promote R-loops at DNA double-strand breaks, we show that it suppresses R-loops and associated DNA damage at transcription-replication conflicts. This occurs through a non-nucleolytic function of MRE11 that is important for R-loop suppression by the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms at transcription-replication conflicts.
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Affiliation(s)
| | - Shuhe Tsai
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Maria J Aristizabal
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - James P Wells
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yan Coulombe
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Franciele F Busatto
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Yujia A Chan
- The Broad Institute of MIT and Harvard University, Cambridge, MA, 02142, USA
| | - Arun Kumar
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Yi Dan Zhu
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | | | | | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada
| | - Michael S Kobor
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Vancouver, V5Z 4H4, Canada
| | - Jean-Yves Masson
- Centre Hospitalier Universitaire de Québec-Universite Laval, Oncology Axis, Quebec City, G1R 2J6, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, G1V 0A6, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, V5Z 4H4, Canada.
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Ray RM, Hansen AH, Slott S, Taskova M, Astakhova K, Morris KV. Control of LDL Uptake in Human Cells by Targeting the LDLR Regulatory Long Non-coding RNA BM450697. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 17:264-276. [PMID: 31279228 PMCID: PMC6611981 DOI: 10.1016/j.omtn.2019.05.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 10/31/2022]
Abstract
Hypercholesterolemia is a condition that is characterized by very high levels of cholesterol in the blood and is a major correlating factor with heart disease. Indeed, high levels of the low-density lipoprotein (LDL) have been causally linked to the development of atherosclerotic cardiovascular disease (ASCVD). A method to specifically reduce cholesterol in the blood in a long-term, stable manner could prove therapeutically relevant. Cholesterol is removed from the blood by the LDL receptor (LDLR) in the liver. Others and we have discovered that a long non-coding RNA (lncRNA; BM450697) functions as an endogenous epigenetic regulator of LDLR and that the repression of this lncRNA by the action of small interfering RNAs (siRNAs) results in the activation of LDLR. We found here, through the interrogation of two siRNAs that can target this lncRNA, both in a transcriptional and post-transcriptional manner, that BM450697 functions as a local scaffold for modulating LDLR transcription. Moreover, we found that conjugation of α-N-acetylgalactosamine (GalNAc) with two lncRNA-directed siRNAs allows for direct liver cell targeting of this lncRNA and functional enhanced uptake of cholesterol. Collectively, these data suggest that targeting the BM450697 lncRNA regulator of LDLR may result in a more specific, long-term, targeted approach to regulating cholesterol in the blood.
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Affiliation(s)
- Roslyn M Ray
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute, 1500 E. Duarte Rd., Duarte, CA, 91010, USA
| | - Anders Højgaard Hansen
- Department of Chemistry, Technical University of Denmark, 206 Kemitorvet, 2800 Kgs Lyngby, Denmark
| | - Sofie Slott
- Department of Chemistry, Technical University of Denmark, 206 Kemitorvet, 2800 Kgs Lyngby, Denmark
| | - Maria Taskova
- Department of Chemistry, Technical University of Denmark, 206 Kemitorvet, 2800 Kgs Lyngby, Denmark
| | - Kira Astakhova
- Department of Chemistry, Technical University of Denmark, 206 Kemitorvet, 2800 Kgs Lyngby, Denmark
| | - Kevin V Morris
- Center for Gene Therapy, City of Hope, Beckman Research Institute and Hematological Malignancy and Stem Cell Transplantation Institute, 1500 E. Duarte Rd., Duarte, CA, 91010, USA.
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44
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Kuznetsov VA, Bondarenko V, Wongsurawat T, Yenamandra SP, Jenjaroenpun P. Toward predictive R-loop computational biology: genome-scale prediction of R-loops reveals their association with complex promoter structures, G-quadruplexes and transcriptionally active enhancers. Nucleic Acids Res 2019; 46:7566-7585. [PMID: 29945198 PMCID: PMC6125637 DOI: 10.1093/nar/gky554] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/08/2018] [Indexed: 12/31/2022] Open
Abstract
R-loops are three-stranded RNA:DNA hybrid structures essential for many normal and pathobiological processes. Previously, we generated a quantitative R-loop forming sequence (RLFS) model, quantitative model of R-loop-forming sequences (QmRLFS) and predicted ∼660 000 RLFSs; most of them located in genes and gene-flanking regions, G-rich regions and disease-associated genomic loci in the human genome. Here, we conducted a comprehensive comparative analysis of these RLFSs using experimental data and demonstrated the high performance of QmRLFS predictions on the nucleotide and genome scales. The preferential co-localization of RLFS with promoters, U1 splice sites, gene ends, enhancers and non-B DNA structures, such as G-quadruplexes, provides evidence for the mechanical linkage between DNA tertiary structures, transcription initiation and R-loops in critical regulatory genome regions. We introduced and characterized an abundant class of reverse-forward RLFS clusters highly enriched in non-B DNA structures, which localized to promoters, gene ends and enhancers. The RLFS co-localization with promoters and transcriptionally active enhancers suggested new models for in cis and in trans regulation by RNA:DNA hybrids of transcription initiation and formation of 3D-chromatin loops. Overall, this study provides a rationale for the discovery and characterization of the non-B DNA regulatory structures involved in the formation of the RNA:DNA interactome as the basis for an emerging quantitative R-loop biology and pathobiology.
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Affiliation(s)
- Vladimir A Kuznetsov
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore.,Department of Urology, Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Vladyslav Bondarenko
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore
| | - Thidathip Wongsurawat
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore.,Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Surya P Yenamandra
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore
| | - Piroon Jenjaroenpun
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore.,Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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45
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Hegedüs É, Kókai E, Nánási P, Imre L, Halász L, Jossé R, Antunovics Z, Webb MR, El Hage A, Pommier Y, Székvölgyi L, Dombrádi V, Szabó G. Endogenous single-strand DNA breaks at RNA polymerase II promoters in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 46:10649-10668. [PMID: 30445637 PMCID: PMC6237785 DOI: 10.1093/nar/gky743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/16/2018] [Indexed: 12/12/2022] Open
Abstract
Molecular combing and gel electrophoretic studies revealed endogenous nicks with free 3'OH ends at ∼100 kb intervals in the genomic DNA (gDNA) of unperturbed and G1-synchronized Saccharomyces cerevisiae cells. Analysis of the distribution of endogenous nicks by Nick ChIP-chip indicated that these breaks accumulated at active RNA polymerase II (RNAP II) promoters, reminiscent of the promoter-proximal transient DNA breaks of higher eukaryotes. Similar periodicity of endogenous nicks was found within the ribosomal rDNA cluster, involving every ∼10th of the tandemly repeated 9.1 kb units of identical sequence. Nicks were mapped by Southern blotting to a few narrow regions within the affected units. Three of them were overlapping the RNAP II promoters, while the ARS-containing IGS2 region was spared of nicks. By using a highly sensitive reverse-Southwestern blot method to map free DNA ends with 3'OH, nicks were shown to be distinct from other known rDNA breaks and linked to the regulation of rDNA silencing. Nicks in rDNA and the rest of the genome were typically found at the ends of combed DNA molecules, occasionally together with R-loops, comprising a major pool of vulnerable sites that are connected with transcriptional regulation.
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Affiliation(s)
- Éva Hegedüs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Endre Kókai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Nánási
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Imre
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Halász
- MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Rozenn Jossé
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Zsuzsa Antunovics
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Aziz El Hage
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Lóránt Székvölgyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Viktor Dombrádi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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46
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High-resolution, strand-specific R-loop mapping via S9.6-based DNA-RNA immunoprecipitation and high-throughput sequencing. Nat Protoc 2019; 14:1734-1755. [PMID: 31053798 DOI: 10.1038/s41596-019-0159-1] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/28/2019] [Indexed: 11/08/2022]
Abstract
R-loops are prevalent three-stranded non-B DNA structures composed of an RNA-DNA hybrid and a single strand of DNA. R-loops are implicated in various basic nuclear processes, such as class-switch recombination, transcription termination and chromatin patterning. Perturbations in R-loop metabolism have been linked to genomic instability and have been implicated in human disorders, including cancer. As a consequence, the accurate mapping of these structures has been of increasing interest in recent years. Here, we describe two related immunoprecipitation-based methods for mapping R-loop structures: basic DRIP-seq (DNA-RNA immunoprecipitation followed by high-throughput DNA sequencing), an easy, robust, but resolution-limited technique; and DRIPc-seq (DNA-RNA immunoprecipitation followed by cDNA conversion coupled to high-throughput sequencing), a high-resolution and strand-specific iteration of the method that permits accurate R-loop mapping genome wide. Briefly, after gentle DNA extraction and restriction digestion with a cocktail of enzymes, R-loop structures are immunoprecipitated with the anti-RNA-DNA hybrid S9.6 antibody. Compared with DRIP-seq, in which the immunoprecipitated DNA is directly sequenced, DRIPc-seq permits the recovery of the RNA moiety of R-loops, and these RNA strands are subjected to strand-specific RNA sequencing (RNA-seq) analysis. DRIPc-seq can be performed in 5 d and can be applied to any cell type, provided sufficient starting material can be collected. Accurately mapping R-loop distribution in various cell lines and under varied conditions is essential to understanding the formation, roles and dynamic resolution of these important structures.
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47
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Chen JY, Zhang X, Fu XD, Chen L. R-ChIP for genome-wide mapping of R-loops by using catalytically inactive RNASEH1. Nat Protoc 2019; 14:1661-1685. [PMID: 30996261 DOI: 10.1038/s41596-019-0154-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 02/21/2019] [Indexed: 11/09/2022]
Abstract
Nascent RNA may form a three-stranded structure with DNA, called an R-loop, which has been linked to fundamental biological processes such as transcription, replication and genome instability. Here, we provide a detailed protocol for a newly developed strategy, named R-ChIP, for robust capture of R-loops genome-wide. Distinct from R-loop-mapping methods based on the monoclonal antibody S9.6, which recognizes RNA-DNA hybrid structures, R-ChIP involves expression of an exogenous catalytically inactive RNASEH1 in cells to bind RNA-DNA hybrids but not resolve them. This is followed by chromatin immunoprecipitation (ChIP) of the tagged RNASEH1 and construction of a strand-specific library for deep sequencing. It takes ~3 weeks to establish a stable cell line expressing the mutant enzyme and 5 more days to proceed with the R-ChIP protocol. In principle, R-ChIP is applicable to both cell lines and animals, as long as the catalytically inactive RNASEH1 can be expressed to study the dynamics of R-loop formation and resolution, as well as its impact on the functionality of the genome. In our recent studies with R-ChIP, we showed an intimate spatiotemporal relationship between R-loops and RNA polymerase II pausing/pause release, as well as linking augmented R-loop formation to DNA damage response induced by driver mutations of key splicing factors associated with myelodysplastic syndrome (MDS).
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Affiliation(s)
- Jia-Yu Chen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xuan Zhang
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Liang Chen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA. .,Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
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48
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Crossley MP, Bocek M, Cimprich KA. R-Loops as Cellular Regulators and Genomic Threats. Mol Cell 2019; 73:398-411. [PMID: 30735654 PMCID: PMC6402819 DOI: 10.1016/j.molcel.2019.01.024] [Citation(s) in RCA: 435] [Impact Index Per Article: 87.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/03/2019] [Accepted: 01/15/2019] [Indexed: 12/17/2022]
Abstract
During transcription, the nascent RNA strand can base pair with its template DNA, displacing the non-template strand as ssDNA and forming a structure called an R-loop. R-loops are common across many domains of life and cause DNA damage in certain contexts. In this review, we summarize recent results implicating R-loops as important regulators of cellular processes such as transcription termination, gene regulation, and DNA repair. We also highlight recent work suggesting that R-loops can be problematic to cells as blocks to efficient transcription and replication that trigger the DNA damage response. Finally, we discuss how R-loops may contribute to cancer, neurodegeneration, and inflammatory diseases and compare the available next-generation sequencing-based approaches to map R-loops genome wide.
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Affiliation(s)
- Madzia P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Michael Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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49
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Abstract
Exposure of genomic, single-stranded DNA (ssDNA) during transcription and replication creates opportunities for the formation of inappropriate secondary structures. Cells manage this exposure by using topoisomerases and helicases to reduce the inherent topological stress that arises from unwinding the double helix and by coating ssDNA with protective protein complexes. Interestingly, specific DNA-RNA hybrids, known as R-loops, form during transcription and exist in homeostasis throughout the genomes of prokaryotes and eukaryotes. These hybrids nucleate from guanine rich clusters in the template strand and extend across GC rich spans of transcribed genes. In vivo regulatory functions have evolved from R-loops, including regulation of gene expression and telomere lengthening. However, they also exist as a form of stress, particularly when replication forks collide with the transcription machinery. New methodologies and models are being developed to delineate the biology of R-loops, including those related to cell stress-based diseases like cancer. As accumulation of R-loops is associated with disease, targeting molecular pathways that regulate their formation or removal could provide new avenues for therapeutic intervention. This review covers recent understandings of the molecular basis for R-loop formation, removal, and biological outcomes in the context of cellular stress.
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Affiliation(s)
- David F Allison
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
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50
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Bouwman BAM, Crosetto N. Endogenous DNA Double-Strand Breaks during DNA Transactions: Emerging Insights and Methods for Genome-Wide Profiling. Genes (Basel) 2018; 9:E632. [PMID: 30558210 PMCID: PMC6316733 DOI: 10.3390/genes9120632] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) jeopardize genome integrity and can-when repaired unfaithfully-give rise to structural rearrangements associated with cancer. Exogenous agents such as ionizing radiation or chemotherapy can invoke DSBs, but a vast amount of breakage arises during vital endogenous DNA transactions, such as replication and transcription. Additionally, chromatin looping involved in 3D genome organization and gene regulation is increasingly recognized as a possible contributor to DSB events. In this review, we first discuss insights into the mechanisms of endogenous DSB formation, showcasing the trade-off between essential DNA transactions and the intrinsic challenges that these processes impose on genomic integrity. In the second part, we highlight emerging methods for genome-wide profiling of DSBs, and discuss future directions of research that will help advance our understanding of genome-wide DSB formation and repair.
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Affiliation(s)
- Britta A M Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
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