1
|
Liu L, Manley JL. Modulation of diverse biological processes by CPSF, the master regulator of mRNA 3' ends. RNA (NEW YORK, N.Y.) 2024; 30:1122-1140. [PMID: 38986572 PMCID: PMC11331416 DOI: 10.1261/rna.080108.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024]
Abstract
The cleavage and polyadenylation specificity factor (CPSF) complex plays a central role in the formation of mRNA 3' ends, being responsible for the recognition of the poly(A) signal sequence, the endonucleolytic cleavage step, and recruitment of poly(A) polymerase. CPSF has been extensively studied for over three decades, and its functions and those of its individual subunits are becoming increasingly well-defined, with much current research focusing on the impact of these proteins on the normal functioning or disease/stress states of cells. In this review, we provide an overview of the general functions of CPSF and its subunits, followed by a discussion of how they exert their functions in a surprisingly diverse variety of biological processes and cellular conditions. These include transcription termination, small RNA processing, and R-loop prevention/resolution, as well as more generally cancer, differentiation/development, and infection/immunity.
Collapse
Affiliation(s)
- Lizhi Liu
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| |
Collapse
|
2
|
Wen X, Xu H, Woolley PR, Conway OM, Yao J, Matouschek A, Lambowitz AM, Paull TT. Senataxin deficiency disrupts proteostasis through nucleolar ncRNA-driven protein aggregation. J Cell Biol 2024; 223:e202309036. [PMID: 38717338 PMCID: PMC11080644 DOI: 10.1083/jcb.202309036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/19/2024] [Accepted: 03/13/2024] [Indexed: 05/12/2024] Open
Abstract
Senataxin is an evolutionarily conserved RNA-DNA helicase involved in DNA repair and transcription termination that is associated with human neurodegenerative disorders. Here, we investigated whether Senataxin loss affects protein homeostasis based on previous work showing R-loop-driven accumulation of DNA damage and protein aggregates in human cells. We find that Senataxin loss results in the accumulation of insoluble proteins, including many factors known to be prone to aggregation in neurodegenerative disorders. These aggregates are located primarily in the nucleolus and are promoted by upregulation of non-coding RNAs expressed from the intergenic spacer region of ribosomal DNA. We also map sites of R-loop accumulation in human cells lacking Senataxin and find higher RNA-DNA hybrids within the ribosomal DNA, peri-centromeric regions, and other intergenic sites but not at annotated protein-coding genes. These findings indicate that Senataxin loss affects the solubility of the proteome through the regulation of transcription-dependent lesions in the nucleus and the nucleolus.
Collapse
Affiliation(s)
- Xuemei Wen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Hengyi Xu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Phillip R. Woolley
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Olivia M. Conway
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jun Yao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Alan M. Lambowitz
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Tanya T. Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| |
Collapse
|
3
|
Wang H, Wu P, Xiong L, Kim HS, Kim JH, Ki JS. Nuclear genome of dinoflagellates: Size variation and insights into evolutionary mechanisms. Eur J Protistol 2024; 93:126061. [PMID: 38394997 DOI: 10.1016/j.ejop.2024.126061] [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: 10/24/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024]
Abstract
Recent progress in high-throughput sequencing technologies has dramatically increased availability of genome data for prokaryotes and eukaryotes. Dinoflagellates have distinct chromosomes and a huge genome size, which make their genomic analysis complicated. Here, we reviewed the nuclear genomes of core dinoflagellates, focusing on the genome and cell size. Till now, the genome sizes of several dinoflagellates (more than 25) have been measured by certain methods (e.g., flow cytometry), showing a range of 3-250 pg of genomic DNA per cell. In contrast to their relatively small cell size, their genomes are huge (about 1-80 times the human haploid genome). In the present study, we collected the genome and cell size data of dinoflagellates and compared their relationships. We found that dinoflagellate genome size exhibits a positive correlation with cell size. On the other hand, we recognized that the genome size is not correlated with phylogenetic relatedness. These may be caused by genome duplication, increased gene copy number, repetitive non-coding DNA, transposon expansion, horizontal gene transfer, organelle-to-nucleus gene transfer, and/or mRNA reintegration into the genome. Ultimate verification of these factors as potential causative mechanisms would require sequencing of more dinoflagellate genomes in the future.
Collapse
Affiliation(s)
- Hui Wang
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China; Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea
| | - Peiling Wu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Lu Xiong
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea
| | - Jin Ho Kim
- Department of Earth and Marine Science, College of Ocean Sciences, Jeju National University, Jeju 63243, Republic of Korea
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea; Department of Biotechnology, Sangmyung University, Seoul 03016, Republic of Korea.
| |
Collapse
|
4
|
Valenzisi P, Marabitti V, Pichierri P, Franchitto A. WRNIP1 prevents transcription-associated genomic instability. eLife 2024; 12:RP89981. [PMID: 38488661 PMCID: PMC10942783 DOI: 10.7554/elife.89981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024] Open
Abstract
R-loops are non-canonical DNA structures that form during transcription and play diverse roles in various physiological processes. Disruption of R-loop homeostasis can lead to genomic instability and replication impairment, contributing to several human diseases, including cancer. Although the molecular mechanisms that protect cells against such events are not fully understood, recent research has identified fork protection factors and DNA damage response proteins as regulators of R-loop dynamics. In this study, we identify the Werner helicase-interacting protein 1 (WRNIP1) as a novel factor that counteracts transcription-associated DNA damage upon replication perturbation. Loss of WRNIP1 leads to R-loop accumulation, resulting in collisions between the replisome and transcription machinery. We observe co-localization of WRNIP1 with transcription/replication complexes and R-loops after replication perturbation, suggesting its involvement in resolving transcription-replication conflicts. Moreover, WRNIP1-deficient cells show impaired replication restart from transcription-induced fork stalling. Notably, transcription inhibition and RNase H1 overexpression rescue all the defects caused by loss of WRNIP1. Importantly, our findings highlight the critical role of WRNIP1 ubiquitin-binding zinc finger (UBZ) domain in preventing pathological persistence of R-loops and limiting DNA damage, thereby safeguarding genome integrity.
Collapse
Affiliation(s)
- Pasquale Valenzisi
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Veronica Marabitti
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Pietro Pichierri
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Annapaola Franchitto
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| |
Collapse
|
5
|
Ramos-Alonso L, Chymkowitch P. Maintaining transcriptional homeostasis during cell cycle. Transcription 2024; 15:1-21. [PMID: 37655806 PMCID: PMC11093055 DOI: 10.1080/21541264.2023.2246868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 09/02/2023] Open
Abstract
The preservation of gene expression patterns that define cellular identity throughout the cell division cycle is essential to perpetuate cellular lineages. However, the progression of cells through different phases of the cell cycle severely disrupts chromatin accessibility, epigenetic marks, and the recruitment of transcriptional regulators. Notably, chromatin is transiently disassembled during S-phase and undergoes drastic condensation during mitosis, which is a significant challenge to the preservation of gene expression patterns between cell generations. This article delves into the specific gene expression and chromatin regulatory mechanisms that facilitate the preservation of transcriptional identity during replication and mitosis. Furthermore, we emphasize our recent findings revealing the unconventional role of yeast centromeres and mitotic chromosomes in maintaining transcriptional fidelity beyond mitosis.
Collapse
Affiliation(s)
- Lucía Ramos-Alonso
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Pierre Chymkowitch
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| |
Collapse
|
6
|
Carrasco B, Torres R, Moreno-del Álamo M, Ramos C, Ayora S, Alonso JC. Processing of stalled replication forks in Bacillus subtilis. FEMS Microbiol Rev 2024; 48:fuad065. [PMID: 38052445 PMCID: PMC10804225 DOI: 10.1093/femsre/fuad065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/30/2023] [Accepted: 12/04/2023] [Indexed: 12/07/2023] Open
Abstract
Accurate DNA replication and transcription elongation are crucial for preventing the accumulation of unreplicated DNA and genomic instability. Cells have evolved multiple mechanisms to deal with impaired replication fork progression, challenged by both intrinsic and extrinsic impediments. The bacterium Bacillus subtilis, which adopts multiple forms of differentiation and development, serves as an excellent model system for studying the pathways required to cope with replication stress to preserve genomic stability. This review focuses on the genetics, single molecule choreography, and biochemical properties of the proteins that act to circumvent the replicative arrest allowing the resumption of DNA synthesis. The RecA recombinase, its mediators (RecO, RecR, and RadA/Sms) and modulators (RecF, RecX, RarA, RecU, RecD2, and PcrA), repair licensing (DisA), fork remodelers (RuvAB, RecG, RecD2, RadA/Sms, and PriA), Holliday junction resolvase (RecU), nucleases (RnhC and DinG), and translesion synthesis DNA polymerases (PolY1 and PolY2) are key functions required to overcome a replication stress, provided that the fork does not collapse.
Collapse
Affiliation(s)
- Begoña Carrasco
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| | - Rubén Torres
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| | - María Moreno-del Álamo
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| | - Cristina Ramos
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| | - Silvia Ayora
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| | - Juan C Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str, 28049 Madrid, Spain
| |
Collapse
|
7
|
Normand C, Dez C, Dauban L, Queille S, Danché S, Abderrahmane S, Beckouet F, Gadal O. RNA polymerase I mutant affects ribosomal RNA processing and ribosomal DNA stability. RNA Biol 2024; 21:1-16. [PMID: 39049162 PMCID: PMC11275518 DOI: 10.1080/15476286.2024.2381910] [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] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 07/27/2024] Open
Abstract
Transcription is a major contributor to genomic instability. The ribosomal RNA (rDNA) gene locus consists of a head-to-tail repeat of the most actively transcribed genes in the genome. RNA polymerase I (RNAPI) is responsible for massive rRNA production, and nascent rRNA is co-transcriptionally assembled with early assembly factors in the yeast nucleolus. In Saccharomyces cerevisiae, a mutant form of RNAPI bearing a fusion of the transcription factor Rrn3 with RNAPI subunit Rpa43 (CARA-RNAPI) has been described previously. Here, we show that the CARA-RNAPI allele results in a novel type of rRNA processing defect, associated with rDNA genomic instability. A fraction of the 35S rRNA produced in CARA-RNAPI mutant escapes processing steps and accumulates. This accumulation is increased in mutants affecting exonucleolytic activities of the exosome complex. CARA-RNAPI is synthetic lethal with monopolin mutants that are known to affect the rDNA condensation. CARA-RNAPI strongly impacts rDNA organization and increases rDNA copy number variation. Reduced rDNA copy number suppresses lethality, suggesting that the chromosome segregation defect is caused by genomic rDNA instability. We conclude that a constitutive association of Rrn3 with transcribing RNAPI results in the accumulation of rRNAs that escape normal processing, impacting rDNA organization and affecting rDNA stability.
Collapse
Affiliation(s)
- Christophe Normand
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Christophe Dez
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Lise Dauban
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Sophie Queille
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Sarah Danché
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Sarra Abderrahmane
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Frederic Beckouet
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Olivier Gadal
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Integrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| |
Collapse
|
8
|
Chatzinikolaou G, Stratigi K, Siametis A, Goulielmaki E, Akalestou-Clocher A, Tsamardinos I, Topalis P, Austin C, Bouwman BA, Crosetto N, Altmüller J, Garinis GA. XPF interacts with TOP2B for R-loop processing and DNA looping on actively transcribed genes. SCIENCE ADVANCES 2023; 9:eadi2095. [PMID: 37939182 PMCID: PMC10631727 DOI: 10.1126/sciadv.adi2095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023]
Abstract
Co-transcriptional RNA-DNA hybrids can not only cause DNA damage threatening genome integrity but also regulate gene activity in a mechanism that remains unclear. Here, we show that the nucleotide excision repair factor XPF interacts with the insulator binding protein CTCF and the cohesin subunits SMC1A and SMC3, leading to R-loop-dependent DNA looping upon transcription activation. To facilitate R-loop processing, XPF interacts and recruits with TOP2B on active gene promoters, leading to double-strand break accumulation and the activation of a DNA damage response. Abrogation of TOP2B leads to the diminished recruitment of XPF, CTCF, and the cohesin subunits to promoters of actively transcribed genes and R-loops and the concurrent impairment of CTCF-mediated DNA looping. Together, our findings disclose an essential role for XPF with TOP2B and the CTCF/cohesin complex in R-loop processing for transcription activation with important ramifications for DNA repair-deficient syndromes associated with transcription-associated DNA damage.
Collapse
Affiliation(s)
- Georgia Chatzinikolaou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
| | - Kalliopi Stratigi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
| | - Athanasios Siametis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Evi Goulielmaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
| | - Alexia Akalestou-Clocher
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Tsamardinos
- Computer Science Department of University of Crete, Heraklion, Crete, Greece
| | - Pantelis Topalis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
| | - Caroline Austin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Britta A. M. Bouwman
- Division of Microbiology, Tumor and Cell Biology, Karolinska Institutet and Science for Life Laboratory, Stockholm 17177, Sweden
| | - Nicola Crosetto
- Division of Microbiology, Tumor and Cell Biology, Karolinska Institutet and Science for Life Laboratory, Stockholm 17177, Sweden
- Human Technopole, Viale Rita Levi-Montalcini 1, 22157 Milan, Italy
| | - Janine Altmüller
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute of Health at Charité–Universitätsmedizin Berlin, Core Facility Genomics, Charitéplatz 1, 10117 Berlin, Germany
| | - George A. Garinis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas, GR70013, Heraklion, Crete, Greece
- Department of Biology, University of Crete, Heraklion, Crete, Greece
| |
Collapse
|
9
|
Gu L, Li M, Li CM, Haratipour P, Lingeman R, Jossart J, Gutova M, Flores L, Hyde C, Kenjić N, Li H, Chung V, Li H, Lomenick B, Von Hoff DD, Synold TW, Aboody KS, Liu Y, Horne D, Hickey RJ, Perry JJP, Malkas LH. Small molecule targeting of transcription-replication conflict for selective chemotherapy. Cell Chem Biol 2023; 30:1235-1247.e6. [PMID: 37531956 PMCID: PMC10592352 DOI: 10.1016/j.chembiol.2023.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 02/12/2023] [Accepted: 07/10/2023] [Indexed: 08/04/2023]
Abstract
Targeting transcription replication conflicts, a major source of endogenous DNA double-stranded breaks and genomic instability could have important anticancer therapeutic implications. Proliferating cell nuclear antigen (PCNA) is critical to DNA replication and repair processes. Through a rational drug design approach, we identified a small molecule PCNA inhibitor, AOH1996, which selectively kills cancer cells. AOH1996 enhances the interaction between PCNA and the largest subunit of RNA polymerase II, RPB1, and dissociates PCNA from actively transcribed chromatin regions, while inducing DNA double-stranded breaks in a transcription-dependent manner. Attenuation of RPB1 interaction with PCNA, by a point mutation in RPB1's PCNA-binding region, confers resistance to AOH1996. Orally administrable and metabolically stable, AOH1996 suppresses tumor growth as a monotherapy or as a combination treatment but causes no discernable side effects. Inhibitors of transcription replication conflict resolution may provide a new and unique therapeutic avenue for exploiting this cancer-selective vulnerability.
Collapse
Affiliation(s)
- Long Gu
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA.
| | - Min Li
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Caroline M Li
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Pouya Haratipour
- Department of Cancer Biology & Molecular Medicine, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Robert Lingeman
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Jennifer Jossart
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Margarita Gutova
- Department of Developmental & Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Linda Flores
- Department of Developmental & Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Caitlyn Hyde
- Department of Developmental & Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Nikola Kenjić
- Department of Biochemistry, University of California Riverside, Riverside, CA, USA
| | - Haiqing Li
- Department of Genomics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Vincent Chung
- Department of Medical Oncology, City of Hope, Duarte, CA, USA
| | - Hongzhi Li
- Department of Bioinformatics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Brett Lomenick
- Proteome Exploration Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Daniel D Von Hoff
- Clinical Translational Research Division, Translational Genomics Research Institute, 445N 5th Street, Phoenix, AZ 85004, USA
| | - Timothy W Synold
- Department of Medical Oncology and Therapeutics Research, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Karen S Aboody
- Department of Developmental & Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Yilun Liu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - David Horne
- Department of Cancer Biology & Molecular Medicine, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Robert J Hickey
- Department of Cancer Biology & Molecular Medicine, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - J Jefferson P Perry
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Linda H Malkas
- Department of Molecular Diagnostics & Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, CA, USA
| |
Collapse
|
10
|
Krachmarova E, Petkov P, Lilkova E, Ilieva N, Rangelov M, Todorova N, Malinova K, Hristova R, Nacheva G, Gospodinov A, Litov L. Insights into the SARS-CoV-2 ORF6 Mechanism of Action. Int J Mol Sci 2023; 24:11589. [PMID: 37511350 PMCID: PMC10380535 DOI: 10.3390/ijms241411589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
ORF6 is responsible for suppressing the immune response of cells infected by the SARS-CoV-2 virus. It is also the most toxic protein of SARS-CoV-2, and its actions are associated with the viral pathogenicity. Here, we study in silico and in vitro the structure of the protein, its interaction with RAE1 and the mechanism of action behind its high toxicity. We show both computationally and experimentally that SARS-CoV-2 ORF6, embedded in the cytoplasmic membranes, binds to RAE1 and sequesters it in the cytoplasm, thus depleting its availability in the nucleus and impairing nucleocytoplasmic mRNA transport. This negatively affects the cellular genome stability by compromising the cell cycle progression into the S-phase and by promoting the accumulation of RNA-DNA hybrids. Understanding the multiple ways in which ORF6 affects DNA replication may also have important implications for elucidating the pathogenicity of SARS-CoV-2 and developing therapeutic strategies to mitigate its deleterious effects on host cells.
Collapse
Affiliation(s)
- Elena Krachmarova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Peicho Petkov
- Faculty of Physics, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria;
| | - Elena Lilkova
- Institute of Information and Communication Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.L.); (N.I.)
| | - Nevena Ilieva
- Institute of Information and Communication Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.L.); (N.I.)
| | - Miroslav Rangelov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Nadezhda Todorova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Kristina Malinova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Rossitsa Hristova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Genoveva Nacheva
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Anastas Gospodinov
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Leandar Litov
- Faculty of Physics, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria;
| |
Collapse
|
11
|
Torres R, Carrasco B, Alonso JC. Bacillus subtilis RadA/Sms-Mediated Nascent Lagging-Strand Unwinding at Stalled or Reversed Forks Is a Two-Step Process: RadA/Sms Assists RecA Nucleation, and RecA Loads RadA/Sms. Int J Mol Sci 2023; 24:ijms24054536. [PMID: 36901969 PMCID: PMC10003422 DOI: 10.3390/ijms24054536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
Replication fork rescue requires Bacillus subtilis RecA, its negative (SsbA) and positive (RecO) mediators, and fork-processing (RadA/Sms). To understand how they work to promote fork remodeling, reconstituted branched replication intermediates were used. We show that RadA/Sms (or its variant, RadA/Sms C13A) binds to the 5'-tail of a reversed fork with longer nascent lagging-strand and unwinds it in the 5'→3' direction, but RecA and its mediators limit unwinding. RadA/Sms cannot unwind a reversed fork with a longer nascent leading-strand, or a gapped stalled fork, but RecA interacts with and activates unwinding. Here, the molecular mechanism by which RadA/Sms, in concert with RecA, in a two-step reaction, unwinds the nascent lagging-strand of reversed or stalled forks is unveiled. First, RadA/Sms, as a mediator, contributes to SsbA displacement from the forks and nucleates RecA onto single-stranded DNA. Then, RecA, as a loader, interacts with and recruits RadA/Sms onto the nascent lagging strand of these DNA substrates to unwind them. Within this process, RecA limits RadA/Sms self-assembly to control fork processing, and RadA/Sms prevents RecA from provoking unnecessary recombination.
Collapse
|
12
|
Tabuloc CA, Cai YD, Kwok RS, Chan EC, Hidalgo S, Chiu JC. CLOCK and TIMELESS regulate rhythmic occupancy of the BRAHMA chromatin-remodeling protein at clock gene promoters. PLoS Genet 2023; 19:e1010649. [PMID: 36809369 PMCID: PMC9983840 DOI: 10.1371/journal.pgen.1010649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 03/03/2023] [Accepted: 02/02/2023] [Indexed: 02/23/2023] Open
Abstract
Circadian clock and chromatin-remodeling complexes are tightly intertwined systems that regulate rhythmic gene expression. The circadian clock promotes rhythmic expression, timely recruitment, and/or activation of chromatin remodelers, while chromatin remodelers regulate accessibility of clock transcription factors to the DNA to influence expression of clock genes. We previously reported that the BRAHMA (BRM) chromatin-remodeling complex promotes the repression of circadian gene expression in Drosophila. In this study, we investigated the mechanisms by which the circadian clock feeds back to modulate daily BRM activity. Using chromatin immunoprecipitation, we observed rhythmic BRM binding to clock gene promoters despite constitutive BRM protein expression, suggesting that factors other than protein abundance are responsible for rhythmic BRM occupancy at clock-controlled loci. Since we previously reported that BRM interacts with two key clock proteins, CLOCK (CLK) and TIMELESS (TIM), we examined their effect on BRM occupancy to the period (per) promoter. We observed reduced BRM binding to the DNA in clk null flies, suggesting that CLK is involved in enhancing BRM occupancy to initiate transcriptional repression at the conclusion of the activation phase. Additionally, we observed reduced BRM binding to the per promoter in flies overexpressing TIM, suggesting that TIM promotes BRM removal from DNA. These conclusions are further supported by elevated BRM binding to the per promoter in flies subjected to constant light and experiments in Drosophila tissue culture in which the levels of CLK and TIM are manipulated. In summary, this study provides new insights into the reciprocal regulation between the circadian clock and the BRM chromatin-remodeling complex.
Collapse
Affiliation(s)
- Christine A. Tabuloc
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Yao D. Cai
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Rosanna S. Kwok
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Elizabeth C. Chan
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Sergio Hidalgo
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Joanna C. Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| |
Collapse
|
13
|
Zhao Q, Liu K, Zhang L, Li Z, Wang L, Cao J, Xu Y, Zheng A, Chen Q, Zhao T. BNIP3-dependent mitophagy safeguards ESC genomic integrity via preventing oxidative stress-induced DNA damage and protecting homologous recombination. Cell Death Dis 2022; 13:976. [PMID: 36402748 PMCID: PMC9675825 DOI: 10.1038/s41419-022-05413-4] [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: 02/14/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/21/2022]
Abstract
Embryonic stem cells (ESCs) have a significantly lower mutation load compared to somatic cells, but the mechanisms that guard genomic integrity in ESCs remain largely unknown. Here we show that BNIP3-dependent mitophagy protects genomic integrity in mouse ESCs. Deletion of Bnip3 increases cellular reactive oxygen species (ROS) and decreases ATP generation. Increased ROS in Bnip3-/- ESCs compromised self-renewal and were partially rescued by either NAC treatment or p53 depletion. The decreased cellular ATP in Bnip3-/- ESCs induced AMPK activation and deteriorated homologous recombination, leading to elevated mutation load during long-term propagation. Whereas activation of AMPK in X-ray-treated Bnip3+/+ ESCs dramatically ascended mutation rates, inactivation of AMPK in Bnip3-/- ESCs under X-ray stress remarkably decreased the mutation load. In addition, enhancement of BNIP3-dependent mitophagy during reprogramming markedly decreased mutation accumulation in established iPSCs. In conclusion, we demonstrated a novel pathway in which BNIP3-dependent mitophagy safeguards ESC genomic stability, and that could potentially be targeted to improve pluripotent stem cell genomic integrity for regenerative medicine.
Collapse
Affiliation(s)
- Qian Zhao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Kun Liu
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Lin Zhang
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Zheng Li
- grid.24696.3f0000 0004 0369 153XDepartment of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Liang Wang
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jiani Cao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Youqing Xu
- grid.24696.3f0000 0004 0369 153XDepartment of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Aihua Zheng
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Quan Chen
- grid.216938.70000 0000 9878 7032College of Life Sciences, Nankai University, Tianjin, 300073 China
| | - Tongbiao Zhao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| |
Collapse
|
14
|
Patitaki E, Schivre G, Zioutopoulou A, Perrella G, Bourbousse C, Barneche F, Kaiserli E. Light, chromatin, action: nuclear events regulating light signaling in Arabidopsis. THE NEW PHYTOLOGIST 2022; 236:333-349. [PMID: 35949052 PMCID: PMC9826491 DOI: 10.1111/nph.18424] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/26/2022] [Indexed: 05/31/2023]
Abstract
The plant nucleus provides a major hub for environmental signal integration at the chromatin level. Multiple light signaling pathways operate and exchange information by regulating a large repertoire of gene targets that shape plant responses to a changing environment. In addition to the established role of transcription factors in triggering photoregulated changes in gene expression, there are eminent reports on the significance of chromatin regulators and nuclear scaffold dynamics in promoting light-induced plant responses. Here, we report and discuss recent advances in chromatin-regulatory mechanisms modulating plant architecture and development in response to light, including the molecular and physiological roles of key modifications such as DNA, RNA and histone methylation, and/or acetylation. The significance of the formation of biomolecular condensates of key light signaling components is discussed and potential applications to agricultural practices overviewed.
Collapse
Affiliation(s)
- Eirini Patitaki
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowG12 8QQUK
| | - Geoffrey Schivre
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERMUniversité PSLParis75005France
- Université Paris‐SaclayOrsay91400France
| | - Anna Zioutopoulou
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowG12 8QQUK
| | - Giorgio Perrella
- Department of BiosciencesUniversity of MilanVia Giovanni Celoria, 2620133MilanItaly
| | - Clara Bourbousse
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERMUniversité PSLParis75005France
| | - Fredy Barneche
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERMUniversité PSLParis75005France
| | - Eirini Kaiserli
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowG12 8QQUK
| |
Collapse
|
15
|
Hauf S, Rotrattanadumrong R, Yokobayashi Y. Analysis of the Sequence Preference of Saporin by Deep Sequencing. ACS Chem Biol 2022; 17:2619-2630. [PMID: 35969718 PMCID: PMC9486812 DOI: 10.1021/acschembio.2c00531] [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: 06/27/2022] [Accepted: 07/29/2022] [Indexed: 01/19/2023]
Abstract
Ribosome-inactivating proteins (RIPs) are RNA:adenosine glycosidases that inactivate eukaryotic ribosomes by depurinating the sarcin-ricin loop (SRL) in 28S rRNA. The GAGA sequence at the top of the SRL or at the top of a hairpin loop is assumed to be their target motif. Saporin is a RIP widely used to develop immunotoxins for research and medical applications, but its sequence specificity has not been investigated. Here, we combine the conventional aniline cleavage assay for depurinated nucleic acids with high-throughput sequencing to study sequence-specific depurination of oligonucleotides caused by saporin. Our data reveal the sequence preference of saporin for different substrates and show that the GAGA motif is not efficiently targeted by this protein, neither in RNA nor in DNA. Instead, a preference of saporin for certain hairpin DNAs was observed. The observed sequence-specific activity of saporin may be relevant to antiviral or apoptosis-inducing effects of RIPs. The developed method could also be useful for studying the sequence specificity of depurination by other RIPs or enzymes.
Collapse
Affiliation(s)
- Samuel Hauf
- Nucleic Acid Chemistry and
Engineering Unit, Okinawa Institute of Science
and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Rachapun Rotrattanadumrong
- Nucleic Acid Chemistry and
Engineering Unit, Okinawa Institute of Science
and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and
Engineering Unit, Okinawa Institute of Science
and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| |
Collapse
|
16
|
Transcription-replication conflicts in primordial germ cells necessitate the Fanconi anemia pathway to safeguard genome stability. Proc Natl Acad Sci U S A 2022; 119:e2203208119. [PMID: 35969748 PMCID: PMC9407672 DOI: 10.1073/pnas.2203208119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Germ cells are capable of preserving their genetic information with high fidelity. We report that rapidly dividing mouse primordial germ cells (PGCs) are faced with high levels of endogenous replication stress due to frequent occurrence of transcription–replication conflicts (TRCs). Thus, PGCs have an increased requirement for the replication-coupled Fanconi anemia (FA) pathway to counteract TRC-induced replication stress, enabling their rapid proliferation to establish a sufficient reproductive reserve. This work provides insights into the unique genome feature of developing PGCs and helps to explain the reproductive defects in FA individuals. Preserving a high degree of genome integrity and stability in germ cells is of utmost importance for reproduction and species propagation. However, the regulatory mechanisms of maintaining genome stability in the developing primordial germ cells (PGCs), in which rapid proliferation is coupled with global hypertranscription, remain largely unknown. Here, we find that mouse PGCs encounter a constitutively high frequency of transcription–replication conflicts (TRCs), which lead to R-loop accumulation and impose endogenous replication stress on PGCs. We further demonstrate that the Fanconi anemia (FA) pathway is activated by TRCs and has a central role in the coordination between replication and transcription in the rapidly proliferating PGCs, as disabling the FA pathway leads to TRC and R-loop accumulation, replication fork destabilization, increased DNA damage, dramatic loss of mitotically dividing mouse PGCs, and consequent sterility of both sexes. Overall, our findings uncover the unique source and resolving mechanism of endogenous replication stress during PGC proliferation, provide a biological explanation for reproductive defects in individuals with FA, and improve our understanding of the monitoring strategies for genome stability during germ cell development.
Collapse
|
17
|
Break-induced replication: unraveling each step. Trends Genet 2022; 38:752-765. [PMID: 35459559 DOI: 10.1016/j.tig.2022.03.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 10/18/2022]
Abstract
Break-induced replication (BIR) repairs one-ended double-strand DNA breaks through invasion into a homologous template followed by DNA synthesis. Different from S-phase replication, BIR copies the template DNA in a migrating displacement loop (D-loop) and results in conservative inheritance of newly synthesized DNA. This unusual mode of DNA synthesis makes BIR a source of various genetic instabilities like those associated with cancer in humans. This review focuses on recent progress in delineating the mechanism of Rad51-dependent BIR in budding yeast. In addition, we discuss new data that describe changes in BIR efficiency and fidelity on encountering replication obstacles as well as the implications of these findings for BIR-dependent processes such as telomere maintenance and the repair of collapsed replication forks.
Collapse
|
18
|
Gómez-González B, Dutta A, Feng W. Editorial: The Role of RNA in Genome Stability: To Wreck or Repair? Front Mol Biosci 2022; 9:848217. [PMID: 35224000 PMCID: PMC8865954 DOI: 10.3389/fmolb.2022.848217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/21/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Belén Gómez-González
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
| |
Collapse
|
19
|
The Cumulative Formation of R-loop Interacts with Histone Modifications to Shape Cell Reprogramming. Int J Mol Sci 2022; 23:ijms23031567. [PMID: 35163490 PMCID: PMC8835745 DOI: 10.3390/ijms23031567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 12/27/2022] Open
Abstract
R-loop, a three-stranded RNA/DNA structure, plays important roles in modulating genome stability and gene expression, but the molecular mechanism of R-loops in cell reprogramming remains elusive. Here, we comprehensively profiled the genome-wide landscape of R-loops during cell reprogramming. The results showed that the R-loop formation on most different types of repetitive elements is stage-specific in cell reprogramming. We unveiled that the cumulative deposition of an R-loop subset is positively correlated with gene expression during reprogramming. More importantly, the dynamic turnover of this R-loop subset is accompanied by the activation of the pluripotent transcriptional regulatory network (TRN). Moreover, the large accumulation of the active histone marker H3K4me3 and the reduction in H3K27me3 were also observed in these R-loop regions. Finally, we characterized the dynamic network of R-loops that facilitates cell fate transitions in reprogramming. Together, our study provides a new clue for deciphering the interplay mechanism between R-loops and HMs to control cell reprogramming.
Collapse
|
20
|
Marabitti V, Valenzisi P, Lillo G, Malacaria E, Palermo V, Pichierri P, Franchitto A. R-Loop-Associated Genomic Instability and Implication of WRN and WRNIP1. Int J Mol Sci 2022; 23:ijms23031547. [PMID: 35163467 PMCID: PMC8836129 DOI: 10.3390/ijms23031547] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 02/05/2023] Open
Abstract
Maintenance of genome stability is crucial for cell survival and relies on accurate DNA replication. However, replication fork progression is under constant attack from different exogenous and endogenous factors that can give rise to replication stress, a source of genomic instability and a notable hallmark of pre-cancerous and cancerous cells. Notably, one of the major natural threats for DNA replication is transcription. Encounters or conflicts between replication and transcription are unavoidable, as they compete for the same DNA template, so that collisions occur quite frequently. The main harmful transcription-associated structures are R-loops. These are DNA structures consisting of a DNA–RNA hybrid and a displaced single-stranded DNA, which play important physiological roles. However, if their homeostasis is altered, they become a potent source of replication stress and genome instability giving rise to several human diseases, including cancer. To combat the deleterious consequences of pathological R-loop persistence, cells have evolved multiple mechanisms, and an ever growing number of replication fork protection factors have been implicated in preventing/removing these harmful structures; however, many others are perhaps still unknown. In this review, we report the current knowledge on how aberrant R-loops affect genome integrity and how they are handled, and we discuss our recent findings on the role played by two fork protection factors, the Werner syndrome protein (WRN) and the Werner helicase-interacting protein 1 (WRNIP1) in response to R-loop-induced genome instability.
Collapse
|
21
|
Abstract
It has recently been demonstrated that budding yeast telomeres are transcribed into TERRA, a long noncoding RNA. Due to the G-rich nature of the coding strand, TERRA has a tendency to form DNA-RNA hybrids and potentially R-loops, which in turn, promote repair at short telomeres. Here, we report two methods to detect DNA-RNA hybrids at yeast telomeres, namely, DRIP, which employs the S9.6 hybrid-recognizing antibody, and R-ChIP, which takes advantage of a catalytic dead form of RNase H1 (Rnh1-cd). We use cross-linked material for both protocols as we have found that this does not negatively affect recovered material, and furthermore allows the precipitation of other proteins from the identical cross-linked material. Although both methods are successful in terms of detecting DNA-RNA hybrids at telomeres, the R-ChIP method yields an approximately ten-fold increased enrichment.
Collapse
Affiliation(s)
- Carolin B Wagner
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg-University Mainz, Mainz, Germany
| | - Brian Luke
- Institute of Molecular Biology (IMB), Mainz, Germany.
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg-University Mainz, Mainz, Germany.
| |
Collapse
|
22
|
Han MM, Hirakawa M, Yamauchi M, Matsuda N. Roles of the SUMO-related enzymes, PIAS1, PIAS4, and RNF4, in DNA double-strand break repair by homologous recombination. Biochem Biophys Res Commun 2021; 591:95-101. [PMID: 35007836 DOI: 10.1016/j.bbrc.2021.12.099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 12/25/2021] [Indexed: 11/02/2022]
Abstract
Post-translational modification of proteins by small ubiquitin-like modifier (SUMO) is known to be involved in a variety of cellular events. This modification, called SUMOylation, is carried out by the E1 activating enzyme, the E2 conjugating enzyme, and multiple E3 ligases. Previous studies have demonstrated that the SUMO E3 ligases, protein inhibitors of activated STAT 1 (PIAS1) and 4 (PIAS4), and the SUMO-targeted ubiquitin ligase, RING finger protein 4 (RNF4), play important roles in the repair of DNA double-strand breaks (DSBs). However, the mechanism by which these SUMO-related enzymes promote DSB repair is still poorly understood. In the present study, we focused on homologous recombination (HR), the most accurate DSB repair pathway, and aimed to elucidate the mechanism by which PIAS1, PIAS4, and RNF4 promote HR. In γ-ray-irradiated normal human fibroblasts, DSB end resection and RAD51 loading, the two essential steps of HR, were significantly impaired by small interfering RNA (siRNA)-mediated depletion of PIAS1, PIAS4, or RNF4. The recruitment of BRCA1, a major HR factor, to DSB sites was reduced in cells depleted of these SUMO-related enzymes. Consistent with the role of BRCA1 in counteracting the p53-binding protein 1 (53BP1)-mediated resection blockade, 53BP1 depletion rescued the reduced resection and RAD51 loading in the cells depleted of PIAS1, PIAS4, or RNF4. Moreover, Rap1-interacting factor 1 (RIF1), a resection inhibitor downstream of 53BP1, became more abundant at DSBs when PIAS1, PIAS4, RNF4, or BRCA1 was depleted. Importantly, the concomitant depletion of BRCA1 with either one of the SUMO-related enzymes did not further increase RIF1 at DSBs, when compared to single depletion of BRCA1. Collectively, these results suggest that PIAS1, PIAS4, RNF4, and BRCA1 work epistatically to counteract 53BP1/RIF1-mediated resection blockade, thereby promoting resection.
Collapse
Affiliation(s)
- Moe Moe Han
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Miyako Hirakawa
- Center for Radiation Research and Education, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Motohiro Yamauchi
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan.
| | - Naoki Matsuda
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8523, Japan; Center for Radiation Research and Education, Nagasaki University, Nagasaki, 852-8523, Japan; Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| |
Collapse
|
23
|
Medium levels of transcription and replication related chromosomal instability are associated with poor clinical outcome. Sci Rep 2021; 11:23429. [PMID: 34873180 PMCID: PMC8648741 DOI: 10.1038/s41598-021-02787-x] [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: 06/22/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022] Open
Abstract
Genomic instability (GI) influences treatment efficacy and resistance, and an accurate measure of it is lacking. Current measures of GI are based on counts of specific structural variation (SV) and mutational signatures. Here, we present a holistic approach to measuring GI based on the quantification of the steady-state equilibrium between DNA damage and repair as assessed by the residual breakpoints (BP) remaining after repair, irrespective of SV type. We use the notion of Hscore, a BP "hotspotness" magnitude scale, to measure the propensity of genomic structural or functional DNA elements to break more than expected by chance. We then derived new measures of transcription- and replication-associated GI that we call iTRAC (transcription-associated chromosomal instability index) and iRACIN (replication-associated chromosomal instability index). We show that iTRAC and iRACIN are predictive of metastatic relapse in Leiomyosarcoma (LMS) and that they may be combined to form a new classifier called MAGIC (mixed transcription- and replication-associated genomic instability classifier). MAGIC outperforms the gold standards FNCLCC and CINSARC in stratifying metastatic risk in LMS. Furthermore, iTRAC stratifies chemotherapeutic response in LMS. We finally show that this approach is applicable to other cancers.
Collapse
|
24
|
Liu Y, Hu Z, Deng Y, Shang L, Gobler CJ, Tang YZ. Dependence of genome size and copy number of rRNA gene on cell volume in dinoflagellates. HARMFUL ALGAE 2021; 109:102108. [PMID: 34815026 DOI: 10.1016/j.hal.2021.102108] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Dinoflagellates are an ecologically important group of protists in aquatic environment and have evolved many unusual and enigmatic genomic features such as immense genome sizes, high repeated genes, and a large portion of hydroxymethyluracil in DNA. Although previous studies have observed positive correlations between the large subunit (LSU) rRNA gene copy number and genome size of a variety of eukaryotic organisms (e.g. higher plants and animals), or between cell volume and LSU rRNA gene copy number, and/or between genome size and cell size, which suggests a possible co-evolution among these three features in different lineages of life, it remains an open question regarding the relationships among these three parameters in dinoflagellates. For the first time, we estimated the copy numbers of the LSU rRNA gene, the genome sizes, and cell volumes within a broad range of dinoflagellates (covering 15 species of 11 genera) using single-cell qPCR-based assay (determining LSU rRNA gene copy number), FlowCAM (cell volume measurement), and ultraviolet spectrophotometry (genome size estimation). The measured copy number of LSU rRNA gene ranged from 398 ± 184 (Prorocentrum minimum) to 152,078 ± 33,555 copies•cell-1 (Alexandrium pacificum), while the genome size and the cell volume ranged from 5.6 ± 0.2 (Karlodinium veneficum) to 853 ± 19.9 pg•cell-1 (Pseliodinium pirum), and from 1,070 ± 225 (Kar. veneficum) to 168,474 ± 124,180 μm3 (Ps. pirum), respectively. Together with the three parameters measured in literature, there are significant positive linear correlations between LSU rRNA gene copy numbers and genome sizes, cell volumes and LSU rRNA gene copy numbers, and between genome sizes and cell volumes via comparisons of multi-model regression analyses, suggesting a dependence of genome size and rRNA gene copy number on the cell volumes of dinoflagellates. Validation of the measurement methods was conducted via comparisons between reported data in the literature and that predicted using the linear equations we obtained, and between genome size measured by flow cytometry (FCM) and ultraviolet spectrophotometry (Nanodrop). These results provide insightful understandings of dinoflagellate evolution in terms of the relationships among genomes, gene copy number, and cell volume, and of rRNA gene-based studies in intra-populational and intra-individual genetic diversity, taxonomy, and diversity assessment in the environment of dinoflagellates. The results also provide a dataset useful for reads calibration in environmental metabarcoding studies of dinoflagellates and selection of candidate species for whole genome sequencing.
Collapse
Affiliation(s)
- Yuyang Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
| | - Zhangxi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Yunyan Deng
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lixia Shang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11790, USA
| | - Ying Zhong Tang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| |
Collapse
|
25
|
Ortega P, Gómez-González B, Aguilera A. Heterogeneity of DNA damage incidence and repair in different chromatin contexts. DNA Repair (Amst) 2021; 107:103210. [PMID: 34416542 DOI: 10.1016/j.dnarep.2021.103210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 11/18/2022]
Abstract
It has been long known that some regions of the genome are more susceptible to damage and mutagenicity than others. Recent advances have determined a critical role of chromatin both in the incidence of damage and in its repair. Thus, chromatin arises as a guardian of the stability of the genome, which is altered in cancer cells. In this review, we focus into the mechanisms by which chromatin influences the occurrence and repair of the most cytotoxic DNA lesions, double-strand breaks, in particular at actively transcribed chromatin or related to DNA replication.
Collapse
Affiliation(s)
- Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain.
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| |
Collapse
|
26
|
Waneka G, Svendsen JM, Havird JC, Sloan DB. Mitochondrial mutations in Caenorhabditis elegans show signatures of oxidative damage and an AT-bias. Genetics 2021; 219:6346985. [PMID: 34849888 DOI: 10.1093/genetics/iyab116] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/09/2021] [Indexed: 01/25/2023] Open
Abstract
Rapid mutation rates are typical of mitochondrial genomes (mtDNAs) in animals, but it is not clear why. The difficulty of obtaining measurements of mtDNA mutation that are not biased by natural selection has stymied efforts to distinguish between competing hypotheses about the causes of high mtDNA mutation rates. Several studies which have measured mtDNA mutations in nematodes have yielded small datasets with conflicting conclusions about the relative abundance of different substitution classes (i.e., the mutation spectrum). We therefore leveraged Duplex Sequencing, a high-fidelity DNA sequencing technique, to characterize de novo mtDNA mutations in Caenorhabditis elegans. This approach detected nearly an order of magnitude more mtDNA mutations than documented in any previous nematode mutation study. Despite an existing extreme AT bias in the C. elegans mtDNA (75.6% AT), we found that a significant majority of mutations increase genomic AT content. Compared to some prior studies in nematodes and other animals, the mutation spectrum reported here contains an abundance of CG→AT transversions, supporting the hypothesis that oxidative damage may be a driver of mtDNA mutations in nematodes. Furthermore, we found an excess of G→T and C→T changes on the coding DNA strand relative to the template strand, consistent with increased exposure to oxidative damage. Analysis of the distribution of mutations across the mtDNA revealed significant variation among protein-coding genes and as well as among neighboring nucleotides. This high-resolution view of mitochondrial mutations in C. elegans highlights the value of this system for understanding relationships among oxidative damage, replication error, and mtDNA mutation.
Collapse
Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
| | - Joshua M Svendsen
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
| | - Justin C Havird
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
| |
Collapse
|
27
|
Gene expression levels modulate germline mutation rates through the compound effects of transcription-coupled repair and damage. Hum Genet 2021; 141:1211-1222. [PMID: 34482438 DOI: 10.1007/s00439-021-02355-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/25/2021] [Indexed: 12/16/2022]
Abstract
Of all mammalian organs, the testis has long been observed to have the most diverse gene expression profile. To account for this widespread gene expression, we have proposed a mechanism termed 'transcriptional scanning', which reduces germline mutation rates through transcription-coupled repair (TCR). Our hypothesis contrasts with an earlier observation that mutation rates are overall positively correlated with gene expression levels in yeast, implying that transcription is mutagenic due to effects dominated by transcription-coupled damage (TCD). Here we report evidence that the compound effects of both TCR and TCD during spermatogenesis modulate human germline mutation rates, with TCR dominating in most genes, thus supporting the transcriptional scanning hypothesis. Our analyses address potentially confounding factors, distinguish the differential mutagenic effects acting on the highly expressed genes and the low-to-moderately expressed genes, and resolve concerns relating to the validation of the results using a de novo mutation dataset. We also discuss the theoretical possibility of transcriptional scanning hypothesis from an evolutionary perspective. Together, these analyses support a model by which the coupling of transcription-coupled repair and damage establishes the pattern of germline mutation rates and provide an evolutionary explanation for widespread gene expression during spermatogenesis.
Collapse
|
28
|
Mechanisms Underlying the Suppression of Chromosome Rearrangements by Ataxia-Telangiectasia Mutated. Genes (Basel) 2021; 12:genes12081232. [PMID: 34440406 PMCID: PMC8392746 DOI: 10.3390/genes12081232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023] Open
Abstract
Chromosome rearrangements are structural variations in chromosomes, such as inversions and translocations. Chromosome rearrangements have been implicated in a variety of human diseases. Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by a broad range of clinical and cellular phenotypes. At the cellular level, one of the most prominent features of A-T cells is chromosome rearrangement, especially that in T lymphocytes. The gene that is defective in A-T is ataxia-telangiectasia mutated (ATM). The ATM protein is a serine/threonine kinase and plays a central role in the cellular response to DNA damage, particularly DNA double-strand breaks. In this review, the mechanisms by which ATM suppresses chromosome rearrangements are discussed.
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
Jiang C, Wang F, Zhang K, Min T, Chen D, Wen Y. Distance-Based Biosensor for Ultrasensitive Detection of Uracil-DNA Glycosylase Using Membrane Filtration of DNA Hydrogel. ACS Sens 2021; 6:2395-2402. [PMID: 34048234 DOI: 10.1021/acssensors.1c00624] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the deoxyribonucleic acid (DNA) repair pathways, DNA repair enzymes have great significance for genomic integrity. As one important initiator of the base-excision repair pathway, the aberrant activity of uracil-DNA glycosylase (UDG) is closely associated with many diseases. Herein, we developed a simple distance-based device for visual detection of UDG activity using a load-free DNA hydrogel. The DNA hydrogel consists of polyacrylamide-DNA chains being bridged by a single-stranded DNA crosslinker containing a responsive uracil base site. UDG can recognize and remove the uracil, resulting in the cleavage effect of the DNA crosslinker strand with the assistance of endonuclease IV (Endo IV). Plugging one end of the capillary tube, the DNA hydrogel acting as a filter membrane separator would control molecules to flow into the tube. The integrity of the DNA hydrogel networks is affected by the excision of UDG. Therefore, taking full advantage of membrane filtration of the DNA hydrogel, the activity of UDG can be quantitatively detected via reading the distance of the red indicator solution in the capillary tube. Without any instruments and complicated procedures, this method realizes high sensitivity and specificity for the detection of UDG as low as 0.02 mU/mL and can even measure UDG in complex cell samples. Additionally, this method is simple, universal, and can be used to screen inhibitors, which shows great potential for point-of-care testing, clinical diagnosis, and drug discovery.
Collapse
Affiliation(s)
- Chao Jiang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Fangfang Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Kexin Zhang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Tiantian Min
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Desheng Chen
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Yongqiang Wen
- Beijing Key Laboratory for Bioengineering and Sensing Technology, Daxing Research Institute, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| |
Collapse
|
31
|
Cristini A, Géraud M, Sordet O. Transcription-associated DNA breaks and cancer: A matter of DNA topology. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 364:195-240. [PMID: 34507784 DOI: 10.1016/bs.ircmb.2021.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Transcription is an essential cellular process but also a major threat to genome integrity. Transcription-associated DNA breaks are particularly detrimental as their defective repair can induce gene mutations and oncogenic chromosomal translocations, which are hallmarks of cancer. The past few years have revealed that transcriptional breaks mainly originate from DNA topological problems generated by the transcribing RNA polymerases. Defective removal of transcription-induced DNA torsional stress impacts on transcription itself and promotes secondary DNA structures, such as R-loops, which can induce DNA breaks and genome instability. Paradoxically, as they relax DNA during transcription, topoisomerase enzymes introduce DNA breaks that can also endanger genome integrity. Stabilization of topoisomerases on chromatin by various anticancer drugs or by DNA alterations, can interfere with transcription machinery and cause permanent DNA breaks and R-loops. Here, we review the role of transcription in mediating DNA breaks, and discuss how deregulation of topoisomerase activity can impact on transcription and DNA break formation, and its connection with cancer.
Collapse
Affiliation(s)
- Agnese Cristini
- Cancer Research Center of Toulouse, INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.
| | - Mathéa Géraud
- Cancer Research Center of Toulouse, INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France
| | - Olivier Sordet
- Cancer Research Center of Toulouse, INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.
| |
Collapse
|
32
|
Kajitani GS, Nascimento LLDS, Neves MRDC, Leandro GDS, Garcia CCM, Menck CFM. Transcription blockage by DNA damage in nucleotide excision repair-related neurological dysfunctions. Semin Cell Dev Biol 2021; 114:20-35. [DOI: 10.1016/j.semcdb.2020.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/18/2020] [Accepted: 10/07/2020] [Indexed: 12/20/2022]
|
33
|
Geijer ME, Zhou D, Selvam K, Steurer B, Mukherjee C, Evers B, Cugusi S, van Toorn M, van der Woude M, Janssens RC, Kok YP, Gong W, Raams A, Lo CSY, Lebbink JHG, Geverts B, Plummer DA, Bezstarosti K, Theil AF, Mitter R, Houtsmuller AB, Vermeulen W, Demmers JAA, Li S, van Vugt MATM, Lans H, Bernards R, Svejstrup JQ, Ray Chaudhuri A, Wyrick JJ, Marteijn JA. Elongation factor ELOF1 drives transcription-coupled repair and prevents genome instability. Nat Cell Biol 2021; 23:608-619. [PMID: 34108662 PMCID: PMC7611218 DOI: 10.1038/s41556-021-00692-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 04/29/2021] [Indexed: 02/05/2023]
Abstract
Correct transcription is crucial for life. However, DNA damage severely impedes elongating RNA polymerase II, causing transcription inhibition and transcription-replication conflicts. Cells are equipped with intricate mechanisms to counteract the severe consequence of these transcription-blocking lesions. However, the exact mechanism and factors involved remain largely unknown. Here, using a genome-wide CRISPR-Cas9 screen, we identified the elongation factor ELOF1 as an important factor in the transcription stress response following DNA damage. We show that ELOF1 has an evolutionarily conserved role in transcription-coupled nucleotide excision repair (TC-NER), where it promotes recruitment of the TC-NER factors UVSSA and TFIIH to efficiently repair transcription-blocking lesions and resume transcription. Additionally, ELOF1 modulates transcription to protect cells against transcription-mediated replication stress, thereby preserving genome stability. Thus, ELOF1 protects the transcription machinery from DNA damage via two distinct mechanisms.
Collapse
Affiliation(s)
- Marit E Geijer
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Di Zhou
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Kathiresan Selvam
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Barbara Steurer
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Chirantani Mukherjee
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Bastiaan Evers
- Oncode Institute, Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Simona Cugusi
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
| | - Marvin van Toorn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Melanie van der Woude
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Roel C Janssens
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Yannick P Kok
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Wenzhi Gong
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Anja Raams
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Calvin S Y Lo
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Joyce H G Lebbink
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Bart Geverts
- Erasmus Optical Imaging Center, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Dalton A Plummer
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Karel Bezstarosti
- Proteomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Arjan F Theil
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Richard Mitter
- Bioinformatics and Biostatistics, The Francis Crick Institute, London, UK
| | - Adriaan B Houtsmuller
- Erasmus Optical Imaging Center, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Wim Vermeulen
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jeroen A A Demmers
- Proteomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Shisheng Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Marcel A T M van Vugt
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hannes Lans
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - René Bernards
- Oncode Institute, Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
| | - Arnab Ray Chaudhuri
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - John J Wyrick
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Jurgen A Marteijn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands.
| |
Collapse
|
34
|
Gorkovskiy A, Verstrepen KJ. The Role of Structural Variation in Adaptation and Evolution of Yeast and Other Fungi. Genes (Basel) 2021; 12:699. [PMID: 34066718 PMCID: PMC8150848 DOI: 10.3390/genes12050699] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 01/12/2023] Open
Abstract
Mutations in DNA can be limited to one or a few nucleotides, or encompass larger deletions, insertions, duplications, inversions and translocations that span long stretches of DNA or even full chromosomes. These so-called structural variations (SVs) can alter the gene copy number, modify open reading frames, change regulatory sequences or chromatin structure and thus result in major phenotypic changes. As some of the best-known examples of SV are linked to severe genetic disorders, this type of mutation has traditionally been regarded as negative and of little importance for adaptive evolution. However, the advent of genomic technologies uncovered the ubiquity of SVs even in healthy organisms. Moreover, experimental evolution studies suggest that SV is an important driver of evolution and adaptation to new environments. Here, we provide an overview of the causes and consequences of SV and their role in adaptation, with specific emphasis on fungi since these have proven to be excellent models to study SV.
Collapse
Affiliation(s)
- Anton Gorkovskiy
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
| | - Kevin J. Verstrepen
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
| |
Collapse
|
35
|
Edwards DS, Maganti R, Tanksley JP, Luo J, Park JJH, Balkanska-Sinclair E, Ling J, Floyd SR. BRD4 Prevents R-Loop Formation and Transcription-Replication Conflicts by Ensuring Efficient Transcription Elongation. Cell Rep 2021; 32:108166. [PMID: 32966794 PMCID: PMC7507985 DOI: 10.1016/j.celrep.2020.108166] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/13/2020] [Accepted: 08/27/2020] [Indexed: 12/29/2022] Open
Abstract
Effective spatio-temporal control of transcription and replication during S-phase is paramount to maintaining genomic integrity and cell survival. Dysregulation of these systems can lead to conflicts between the transcription and replication machinery, causing DNA damage and cell death. BRD4 allows efficient transcriptional elongation by stimulating phosphorylation of RNA polymerase II (RNAPII). We report that bromodomain and extra-terminal domain (BET) protein loss of function (LOF) causes RNAPII pausing on the chromatin and DNA damage affecting cells in S-phase. This persistent RNAPII-dependent pausing leads to an accumulation of RNA:DNA hybrids (R-loops) at sites of BRD4 occupancy, leading to transcription-replication conflicts (TRCs), DNA damage, and cell death. Finally, our data show that the BRD4 C-terminal domain, which interacts with P-TEFb, is required to prevent R-loop formation and DNA damage caused by BET protein LOF.
Collapse
Affiliation(s)
- Drake S Edwards
- Medical Scientist Training Program, Duke University School of Medicine, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Jarred P Tanksley
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jie Luo
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | - James J H Park
- Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA
| | | | | | - Scott R Floyd
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710, USA.
| |
Collapse
|
36
|
Moreno-del Álamo M, Carrasco B, Torres R, Alonso JC. Bacillus subtilis PcrA Helicase Removes Trafficking Barriers. Cells 2021; 10:935. [PMID: 33920686 PMCID: PMC8074105 DOI: 10.3390/cells10040935] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/27/2022] Open
Abstract
Bacillus subtilis PcrA interacts with the RNA polymerase and might contribute to mitigate replication-transcription conflicts (RTCs). We show that PcrA depletion lethality is partially suppressed by rnhB inactivation, but cell viability is significantly reduced by rnhC or dinG inactivation. Following PcrA depletion, cells lacking RnhC or DinG are extremely sensitive to DNA damage. Chromosome segregation is not further impaired by rnhB or dinG inactivation but is blocked by rnhC or recA inactivation upon PcrA depletion. Despite our efforts, we could not construct a ΔrnhC ΔrecA strain. These observations support the idea that PcrA dismantles RTCs. Purified PcrA, which binds single-stranded (ss) DNA over RNA, is a ssDNA-dependent ATPase and preferentially unwinds DNA in a 3'→5'direction. PcrA unwinds a 3'-tailed RNA of an RNA-DNA hybrid significantly faster than that of a DNA substrate. Our results suggest that a replicative stress, caused by mis-incorporated rNMPs, indirectly increases cell viability upon PcrA depletion. We propose that PcrA, in concert with RnhC or DinG, contributes to removing spontaneous or enzyme-driven R-loops, to counteract deleterious trafficking conflicts and preserve to genomic integrity.
Collapse
Affiliation(s)
| | | | | | - Juan Carlos Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 28049 Madrid, Spain; (M.M.-d.Á.); (B.C.); (R.T.)
| |
Collapse
|
37
|
Herrero-Ruiz A, Martínez-García PM, Terrón-Bautista J, Millán-Zambrano G, Lieberman JA, Jimeno-González S, Cortés-Ledesma F. Topoisomerase IIα represses transcription by enforcing promoter-proximal pausing. Cell Rep 2021; 35:108977. [PMID: 33852840 PMCID: PMC8052185 DOI: 10.1016/j.celrep.2021.108977] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 02/05/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
Accumulation of topological stress in the form of DNA supercoiling is inherent to the advance of RNA polymerase II (Pol II) and needs to be resolved by DNA topoisomerases to sustain productive transcriptional elongation. Topoisomerases are therefore considered positive facilitators of transcription. Here, we show that, in contrast to this general assumption, human topoisomerase IIα (TOP2A) activity at promoters represses transcription of immediate early genes such as c-FOS, maintaining them under basal repressed conditions. Thus, TOP2A inhibition creates a particular topological context that results in rapid release from promoter-proximal pausing and transcriptional upregulation, which mimics the typical bursting behavior of these genes in response to physiological stimulus. We therefore describe the control of promoter-proximal pausing by TOP2A as a layer for the regulation of gene expression, which can act as a molecular switch to rapidly activate transcription, possibly by regulating the accumulation of DNA supercoiling at promoter regions.
Collapse
Affiliation(s)
- Andrés Herrero-Ruiz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain; Topology and DNA Breaks Group, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Pedro Manuel Martínez-García
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - José Terrón-Bautista
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Gonzalo Millán-Zambrano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | | | - Silvia Jimeno-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain; Departamento de Genética, Universidad de Sevilla, Sevilla 41080, Spain.
| | - Felipe Cortés-Ledesma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain; Topology and DNA Breaks Group, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain.
| |
Collapse
|
38
|
ARID1A regulates R-loop associated DNA replication stress. PLoS Genet 2021; 17:e1009238. [PMID: 33826602 PMCID: PMC8055027 DOI: 10.1371/journal.pgen.1009238] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/19/2021] [Accepted: 03/20/2021] [Indexed: 01/29/2023] Open
Abstract
ARID1A is a core DNA-binding subunit of the BAF chromatin remodeling complex, and is lost in up to 7% of all cancers. The frequency of ARID1A loss increases in certain cancer types, such as clear cell ovarian carcinoma where ARID1A protein is lost in about 50% of cases. While the impact of ARID1A loss on the function of the BAF chromatin remodeling complexes is likely to drive oncogenic gene expression programs in specific contexts, ARID1A also binds genome stability regulators such as ATR and TOP2. Here we show that ARID1A loss leads to DNA replication stress associated with R-loops and transcription-replication conflicts in human cells. These effects correlate with altered transcription and replication dynamics in ARID1A knockout cells and to reduced TOP2A binding at R-loop sites. Together this work extends mechanisms of replication stress in ARID1A deficient cells with implications for targeting ARID1A deficient cancers. DNA is an incredibly busy molecule. It is bound by an ever-changing array of proteins, which control how our cells read the instructions encoded within DNA, through a process called transcription. DNA also must be replicated, condensed, and segregated every time a cell divides. These processes of DNA replicating and transcribing must not interfere with one another or the cell risks damage to DNA and potentially changes to the DNA code called mutations. In cancer many DNA transactions are perturbed, and this has been associated with damaging collisions between replication and transcription. Here we find that a gene called ARID1A, which is frequently lost in cancer cells, prevents such collisions between replication and transcription machinery. Loss of ARID1A has many effects on the cell, but in this context it seems to change the location and activity of an important regulator of DNA twisting and untangling called Topoisomerase 2A. Understanding how loss of ARID1A creates stresses on dividing cancer cells provides new opportunities to develop or apply therapies that could exploit this stress.
Collapse
|
39
|
Wang J, Rojas P, Mao J, Mustè Sadurnì M, Garnier O, Xiao S, Higgs MR, Garcia P, Saponaro M. Persistence of RNA transcription during DNA replication delays duplication of transcription start sites until G2/M. Cell Rep 2021; 34:108759. [PMID: 33596418 PMCID: PMC7900609 DOI: 10.1016/j.celrep.2021.108759] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 11/09/2020] [Accepted: 01/26/2021] [Indexed: 12/22/2022] Open
Abstract
As transcription and replication use DNA as substrate, conflicts between transcription and replication can occur, leading to genome instability with direct consequences for human health. To determine how the two processes are coordinated throughout S phase, we characterize both processes together at high resolution. We find that transcription occurs during DNA replication, with transcription start sites (TSSs) not fully replicated along with surrounding regions and remaining under-replicated until late in the cell cycle. TSSs undergo completion of DNA replication specifically when cells enter mitosis, when RNA polymerase II is removed. Intriguingly, G2/M DNA synthesis occurs at high frequency in unperturbed cell culture, but it is not associated with increased DNA damage and is fundamentally separated from mitotic DNA synthesis. TSSs duplicated in G2/M are characterized by a series of specific features, including high levels of antisense transcription, making them difficult to duplicate during S phase.
Collapse
Affiliation(s)
- Jianming Wang
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Patricia Rojas
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Jingwen Mao
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Martina Mustè Sadurnì
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Olivia Garnier
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Songshu Xiao
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Martin R Higgs
- Lysine Methylation and DNA Damage Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Paloma Garcia
- Stem Cells and Genome Stability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Marco Saponaro
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| |
Collapse
|
40
|
Sengupta P, Bose D, Chatterjee S. The Molecular Tête-à-Tête between G-Quadruplexes and the i-motif in the Human Genome. Chembiochem 2021; 22:1517-1537. [PMID: 33355980 DOI: 10.1002/cbic.202000703] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/16/2020] [Indexed: 12/22/2022]
Abstract
G-Quadruplex (GQ) and i-motif structures are the paradigmatic examples of nonclassical tetrastranded nucleic acids having multifarious biological functions and widespread applications in therapeutics and material science. Recently, tetraplexes emerged as promising anticancer targets due to their structural robustness, gene-regulatory roles, and predominant distribution at specific loci of oncogenes. However, it is arguable whether the i-motif evolves in the complementary single-stranded region after GQ formation in its opposite strand and vice versa. In this review, we address the prerequisites and significance of the simultaneous and/or mutually exclusive formation of GQ and i-motif structures at complementary and sequential positions in duplexes in the cellular milieu. We discussed how their dynamic interplay Sets up cellular homeostasis and exacerbates carcinogenesis. The review gives insights into the spatiotemporal formation of GQ and i-motifs that could be harnessed to design different types of reporter systems and diagnostic platforms for potential bioanalytical and therapeutic intervention.
Collapse
Affiliation(s)
- Pallabi Sengupta
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| | - Debopriya Bose
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| |
Collapse
|
41
|
Yang Z, Li M, Sun Q. RHON1 Co-transcriptionally Resolves R-Loops for Arabidopsis Chloroplast Genome Maintenance. Cell Rep 2021; 30:243-256.e5. [PMID: 31914390 DOI: 10.1016/j.celrep.2019.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/24/2019] [Accepted: 12/02/2019] [Indexed: 01/10/2023] Open
Abstract
Preventing transcription-replication head-on conflict (HO-TRC)-triggered R-loop formation is essential for maintaining genome integrity in bacteria, plants, and mammals. The R-loop eraser RNase H can efficiently relax HO-TRCs. However, it is not clear how organisms resist HO-TRC-triggered R-loops when RNase H proteins are deficient. By screening factors that may relieve R-loop accumulation in the Arabidopsis atrnh1c mutant, we find that overexpression of the R-loop helicase RHON1 can rescue the defects of aberrantly accumulated HO-TRC-triggered R-loops co-transcriptionally. In addition, we find that RHON1 interacts with and orchestrates the transcriptional activity of plastid-encoded RNA polymerases to release the conflicts between transcription and replication. Our study illustrates that organisms employ multiple mechanisms to escape HO-TRC-triggered R-loop accumulation and thus maintain genome integrity.
Collapse
Affiliation(s)
- Zhuo Yang
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Mengmeng Li
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qianwen Sun
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
42
|
WDR82/PNUTS-PP1 Prevents Transcription-Replication Conflicts by Promoting RNA Polymerase II Degradation on Chromatin. Cell Rep 2020; 33:108469. [PMID: 33264625 DOI: 10.1016/j.celrep.2020.108469] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/05/2020] [Accepted: 11/10/2020] [Indexed: 02/08/2023] Open
Abstract
Transcription-replication (T-R) conflicts cause replication stress and loss of genome integrity. However, the transcription-related processes that restrain such conflicts are poorly understood. Here, we demonstrate that the RNA polymerase II (RNAPII) C-terminal domain (CTD) phosphatase protein phosphatase 1 (PP1) nuclear targeting subunit (PNUTS)-PP1 inhibits replication stress. Depletion of PNUTS causes lower EdU uptake, S phase accumulation, and slower replication fork rates. In addition, the PNUTS binding partner WDR82 also promotes RNAPII-CTD dephosphorylation and suppresses replication stress. RNAPII has a longer residence time on chromatin after depletion of PNUTS or WDR82. Furthermore, the RNAPII residence time is greatly enhanced by proteasome inhibition in control cells but less so in PNUTS- or WDR82-depleted cells, indicating that PNUTS and WDR82 promote degradation of RNAPII on chromatin. Notably, reduced replication is dependent on transcription and the phospho-CTD binding protein CDC73 after depletion of PNUTS/WDR82. Altogether, our results suggest that RNAPII-CTD dephosphorylation is required for the continuous turnover of RNAPII on chromatin, thereby preventing T-R conflicts.
Collapse
|
43
|
Prendergast L, McClurg UL, Hristova R, Berlinguer-Palmini R, Greener S, Veitch K, Hernandez I, Pasero P, Rico D, Higgins JMG, Gospodinov A, Papamichos-Chronakis M. Resolution of R-loops by INO80 promotes DNA replication and maintains cancer cell proliferation and viability. Nat Commun 2020; 11:4534. [PMID: 32913330 PMCID: PMC7484789 DOI: 10.1038/s41467-020-18306-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 08/18/2020] [Indexed: 02/04/2023] Open
Abstract
Collisions between the DNA replication machinery and co-transcriptional R-loops can impede DNA synthesis and are a major source of genomic instability in cancer cells. How cancer cells deal with R-loops to proliferate is poorly understood. Here we show that the ATP-dependent chromatin remodelling INO80 complex promotes resolution of R-loops to prevent replication-associated DNA damage in cancer cells. Depletion of INO80 in prostate cancer PC3 cells leads to increased R-loops. Overexpression of the RNA:DNA endonuclease RNAse H1 rescues the DNA synthesis defects and suppresses DNA damage caused by INO80 depletion. R-loops co-localize with and promote recruitment of INO80 to chromatin. Artificial tethering of INO80 to a LacO locus enabled turnover of R-loops in cis. Finally, counteracting R-loops by INO80 promotes proliferation and averts DNA damage-induced death in cancer cells. Our work suggests that INO80-dependent resolution of R-loops promotes DNA replication in the presence of transcription, thus enabling unlimited proliferation in cancers.
Collapse
Affiliation(s)
- Lisa Prendergast
- Cancer Research UK Newcastle Drug Discovery Unit, Newcastle University Centre for Cancer, Newcastle University, Paul O'Gorman Building, Newcastle upon Tyne, NE2 4HH, UK
- Drug Discovery Unit, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, SK10 4TG, Manchester, UK
| | - Urszula L McClurg
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Rossitsa Hristova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | | | - Sarah Greener
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Katie Veitch
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Inmaculada Hernandez
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain
| | - Philippe Pasero
- Institute of Human Genetics, CNRS UMR9002 and University of Montpellier, Equipe Labéllisée Ligue Contre le Cancer, 34090, Montpellier, France
| | - Daniel Rico
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | | | - Anastas Gospodinov
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
| | - Manolis Papamichos-Chronakis
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK.
| |
Collapse
|
44
|
Depletion of the MFAP1/SPP381 Splicing Factor Causes R-Loop-Independent Genome Instability. Cell Rep 2020; 28:1551-1563.e7. [PMID: 31390568 PMCID: PMC6693559 DOI: 10.1016/j.celrep.2019.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 03/18/2019] [Accepted: 07/01/2019] [Indexed: 01/19/2023] Open
Abstract
THO/TREX is a conserved complex with a role in messenger ribonucleoprotein biogenesis that links gene expression and genome instability. Here, we show that human THO interacts with MFAP1 (microfibrillar-associated protein 1), a spliceosome-associated factor. Interestingly, MFAP1 depletion impairs cell proliferation and genome integrity, increasing γH2AX foci and DNA breaks. This phenotype is not dependent on either transcription or RNA-DNA hybrids. Mutations in the yeast orthologous gene SPP381 cause similar transcription-independent genome instability, supporting a conserved role. MFAP1 depletion has a wide effect on splicing and gene expression in human cells, determined by transcriptome analyses. MFAP1 depletion affects a number of DNA damage response (DDR) genes, which supports an indirect role of MFAP1 on genome integrity. Our work defines a functional interaction between THO and RNA processing and argues that splicing factors may contribute to genome integrity indirectly by regulating the expression of DDR genes rather than by a direct role.
Collapse
|
45
|
Analyzing Homologous Recombination at a Genome-Wide Level. Methods Mol Biol 2020. [PMID: 32840796 DOI: 10.1007/978-1-0716-0644-5_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Among the types of damage, DNA double-strand breaks (DSBs) (provoked by various environmental stresses, but also during normal cell metabolic activity) are the most deleterious, as illustrated by the variety of human diseases associated with DSB repair defects. DSBs are repaired by two groups of pathways: homologous recombination (HR) and nonhomologous end joining. These pathways do not trigger the same mutational signatures, and multiple factors, such as cell cycle stage, the complexity of the lesion and also the genomic location, contribute to the choice between these repair pathways. To study the usage of the HR machinery at DSBs, we propose a genome-wide method based on the chromatin immunoprecipitation of the HR core component Rad51, followed by high-throughput sequencing.
Collapse
|
46
|
Deregulated levels of RUVBL1 induce transcription-dependent replication stress. Int J Biochem Cell Biol 2020; 128:105839. [PMID: 32846207 DOI: 10.1016/j.biocel.2020.105839] [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: 05/16/2020] [Revised: 08/11/2020] [Accepted: 08/20/2020] [Indexed: 12/16/2022]
Abstract
Chromatin regulators control transcription and replication, however if and how they might influence the coordination of these processes still is largely unknown. RUVBL1 and the related ATPase RUVBL2 participate in multiple nuclear processes and are implicated in cancer. Here, we report that both the excess and the deficit of the chromatin regulator RUVBL1 impede DNA replication as a consequence of altered transcription. Surprisingly, cells that either overexpressed or were silenced for RUVBL1 had slower replication fork rates and accumulated phosphorylated H2AX, dependent on active transcription. However, the mechanisms of transcription-dependent replication stress were different when RUVBL1 was overexpressed and when depleted. RUVBL1 overexpression led to increased c-Myc-dependent pause release of RNAPII, as evidenced by higher overall transcription, much stronger Ser2 phosphorylation of Rpb1- C-terminal domain, and enhanced colocalization of Rpb1 and c-Myc. RUVBL1 deficiency resulted in increased ubiquitination of Rpb1 and reduced mobility of an RNAP subunit, suggesting accumulation of stalled RNAPIIs on chromatin. Overall, our data show that by modulating the state of RNAPII complexes, RUVBL1 deregulation induces replication-transcription interference and compromises genome integrity during S-phase.
Collapse
|
47
|
Promonet A, Padioleau I, Liu Y, Sanz L, Biernacka A, Schmitz AL, Skrzypczak M, Sarrazin A, Mettling C, Rowicka M, Ginalski K, Chedin F, Chen CL, Lin YL, Pasero P. Topoisomerase 1 prevents replication stress at R-loop-enriched transcription termination sites. Nat Commun 2020; 11:3940. [PMID: 32769985 PMCID: PMC7414224 DOI: 10.1038/s41467-020-17858-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 07/14/2020] [Indexed: 12/30/2022] Open
Abstract
R-loops have both positive and negative impacts on chromosome functions. To identify toxic R-loops in the human genome, here, we map RNA:DNA hybrids, replication stress markers and DNA double-strand breaks (DSBs) in cells depleted for Topoisomerase I (Top1), an enzyme that relaxes DNA supercoiling and prevents R-loop formation. RNA:DNA hybrids are found at both promoters (TSS) and terminators (TTS) of highly expressed genes. In contrast, the phosphorylation of RPA by ATR is only detected at TTS, which are preferentially replicated in a head-on orientation relative to the direction of transcription. In Top1-depleted cells, DSBs also accumulate at TTS, leading to persistent checkpoint activation, spreading of γ-H2AX on chromatin and global replication fork slowdown. These data indicate that fork pausing at the TTS of highly expressed genes containing R-loops prevents head-on conflicts between replication and transcription and maintains genome integrity in a Top1-dependent manner.
Collapse
Affiliation(s)
- Alexy Promonet
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Ismaël Padioleau
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
- Institut Gustave Roussy, Villejuif, France
| | - Yaqun Liu
- Institut Curie, PSL Research University, CNRS, UMR3244, Sorbonne Université, Paris, France
| | - Lionel Sanz
- Department of Molecular and Cellular Biology, University of California, Davis, CA, 95616, USA
| | - Anna Biernacka
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Anne-Lyne Schmitz
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France
| | - Magdalena Skrzypczak
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Amélie Sarrazin
- BioCampus Montpellier, CNRS et Université de Montpellier, Montpellier, France
| | - Clément Mettling
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Montpellier, France
| | - Maga Rowicka
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Frédéric Chedin
- Department of Molecular and Cellular Biology, University of California, Davis, CA, 95616, USA
| | - Chun-Long Chen
- Institut Curie, PSL Research University, CNRS, UMR3244, Sorbonne Université, Paris, France.
| | - Yea-Lih Lin
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France.
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS et Université de Montpellier, Equipe labélisée Ligue contre le Cancer, Montpellier, France.
| |
Collapse
|
48
|
3D genome organization contributes to genome instability at fragile sites. Nat Commun 2020; 11:3613. [PMID: 32680994 PMCID: PMC7367836 DOI: 10.1038/s41467-020-17448-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/30/2020] [Indexed: 12/15/2022] Open
Abstract
Common fragile sites (CFSs) are regions susceptible to replication stress and are hotspots for chromosomal instability in cancer. Several features were suggested to underlie CFS instability, however, these features are prevalent across the genome. Therefore, the molecular mechanisms underlying CFS instability remain unclear. Here, we explore the transcriptional profile and DNA replication timing (RT) under mild replication stress in the context of the 3D genome organization. The results reveal a fragility signature, comprised of a TAD boundary overlapping a highly transcribed large gene with APH-induced RT-delay. This signature enables precise mapping of core fragility regions in known CFSs and identification of novel fragile sites. CFS stability may be compromised by incomplete DNA replication and repair in TAD boundaries core fragility regions leading to genomic instability. The identified fragility signature will allow for a more comprehensive mapping of CFSs and pave the way for investigating mechanisms promoting genomic instability in cancer. Common fragile sites are regions susceptible to replication stress and are prone to chromosomal instability. Here, the authors, by analyzing the contribution of 3D chromatin organization, identify and characterize a fragility signature and precisely map these fragility regions.
Collapse
|
49
|
Rodionov AV, Amosova AV, Krainova LM, Machs EM, Mikhailova YV, Gnutikov AA, Muravenko OV, Loskutov IG. Phenomenon of Multiple Mutations in the 35S rRNA Genes of the C Subgenome of Polyploid Avena L. RUSS J GENET+ 2020. [DOI: 10.1134/s1022795420060095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
50
|
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.
Collapse
|