1
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Rojas P, Wang J, Guglielmi G, Sadurnì MM, Pavlou L, Leung GHD, Rajagopal V, Spill F, Saponaro M. Genome-wide identification of replication fork stalling/pausing sites and the interplay between RNA Pol II transcription and DNA replication progression. Genome Biol 2024; 25:126. [PMID: 38773641 PMCID: PMC11106976 DOI: 10.1186/s13059-024-03278-8] [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: 01/27/2023] [Accepted: 05/14/2024] [Indexed: 05/24/2024] Open
Abstract
BACKGROUND DNA replication progression can be affected by the presence of physical barriers like the RNA polymerases, leading to replication stress and DNA damage. Nonetheless, we do not know how transcription influences overall DNA replication progression. RESULTS To characterize sites where DNA replication forks stall and pause, we establish a genome-wide approach to identify them. This approach uses multiple timepoints during S-phase to identify replication fork/stalling hotspots as replication progresses through the genome. These sites are typically associated with increased DNA damage, overlapped with fragile sites and with breakpoints of rearrangements identified in cancers but do not overlap with replication origins. Overlaying these sites with a genome-wide analysis of RNA polymerase II transcription, we find that replication fork stalling/pausing sites inside genes are directly related to transcription progression and activity. Indeed, we find that slowing down transcription elongation slows down directly replication progression through genes. This indicates that transcription and replication can coexist over the same regions. Importantly, rearrangements found in cancers overlapping transcription-replication collision sites are detected in non-transformed cells and increase following treatment with ATM and ATR inhibitors. At the same time, we find instances where transcription activity favors replication progression because it reduces histone density. CONCLUSIONS Altogether, our findings highlight how transcription and replication overlap during S-phase, with both positive and negative consequences for replication fork progression and genome stability by the coexistence of these two processes.
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Affiliation(s)
- Patricia Rojas
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jianming Wang
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Giovanni Guglielmi
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Martina Mustè Sadurnì
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Lucas Pavlou
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Geoffrey Ho Duen Leung
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Vijay Rajagopal
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Fabian Spill
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Marco Saponaro
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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2
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Kwok ACM, Li C, Lam WT, Wong JTY. Responses of dinoflagellate cells to ultraviolet-C irradiation. Environ Microbiol 2022; 24:5936-5950. [PMID: 35837869 DOI: 10.1111/1462-2920.16135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 06/30/2022] [Accepted: 07/09/2022] [Indexed: 01/12/2023]
Abstract
Dinoflagellates are important aquatic microbes and major harmful algal bloom (HAB) agents that form invasive species through ship ballast transfer. UV-C installations are recommended for ballast treatments and HAB controls, but there is a lack of knowledge in dinoflagellate responses to UV-C. We report here dose-dependent cell cycle delay and viability loss of dinoflagellate cells irradiated with UV-C, with significant proliferative reduction at 800 Jm-2 doses or higher, but immediate LD50 was in the range of 2400-3200 Jm-2 . At higher dosages, some dinoflagellate cells surprisingly survived after days of recovery incubation, and continued viability loss, with samples exhibiting DNA fragmentations per proliferative resumption. Sequential cell cycle postponements, suggesting DNA damages were repaired over one cell cycle, were revealed with flow cytometric analysis and transcriptomic analysis. Over a sustained level of other DNA damage repair pathways, transcript elevation was observed only for several components of base pair repair and mismatch repair. Cumulatively, our findings demonstrated special DNA damage responses in dinoflagellate cells, which we discussed in relation to their unique chromo-genomic characters, as well as indicating resilience of dinoflagellate cells to UV-C.
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Affiliation(s)
- Alvin Chun Man Kwok
- Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Chongping Li
- Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong.,Department of Ocean Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Wing Tai Lam
- Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Joseph Tin Yum Wong
- Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
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3
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Cuartas J, Gangwani L. R-loop Mediated DNA Damage and Impaired DNA Repair in Spinal Muscular Atrophy. Front Cell Neurosci 2022; 16:826608. [PMID: 35783101 PMCID: PMC9243258 DOI: 10.3389/fncel.2022.826608] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/23/2022] [Indexed: 12/02/2022] Open
Abstract
Defects in DNA repair pathways are a major cause of DNA damage accumulation leading to genomic instability and neurodegeneration. Efficient DNA damage repair is critical to maintain genomicstability and support cell function and viability. DNA damage results in the activation of cell death pathways, causing neuronal death in an expanding spectrum of neurological disorders, such as amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), Alzheimer’s disease (AD), and spinal muscular atrophy (SMA). SMA is a neurodegenerative disorder caused by mutations in the Survival Motor Neuron 1 (SMN1) gene. SMA is characterized by the degeneration of spinal cord motor neurons due to low levels of the SMN protein. The molecular mechanism of selective motor neuron degeneration in SMA was unclear for about 20 years. However, several studies have identified biochemical and molecular mechanisms that may contribute to the predominant degeneration of motor neurons in SMA, including the RhoA/ROCK, the c-Jun NH2-terminal kinase (JNK), and p53-mediated pathways, which are involved in mediating DNA damage-dependent cell death. Recent studies provided insight into selective degeneration of motor neurons, which might be caused by accumulation of R-loop-mediated DNA damage and impaired non-homologous end joining (NHEJ) DNA repair pathway leading to genomic instability. Here, we review the latest findings involving R-loop-mediated DNA damage and defects in neuron-specific DNA repair mechanisms in SMA and discuss these findings in the context of other neurodegenerative disorders linked to DNA damage.
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Affiliation(s)
- Juliana Cuartas
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- Francis Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- *Correspondence: Laxman Gangwani
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4
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Sanchez A, Buck-Koehntop BA, Miller KM. Joining the PARty: PARP Regulation of KDM5A during DNA Repair (and Transcription?). Bioessays 2022; 44:e2200015. [PMID: 35532219 DOI: 10.1002/bies.202200015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 11/05/2022]
Abstract
The lysine demethylase KDM5A collaborates with PARP1 and the histone variant macroH2A1.2 to modulate chromatin to promote DNA repair. Indeed, KDM5A engages poly(ADP-ribose) (PAR) chains at damage sites through a previously uncharacterized coiled-coil domain, a novel binding mode for PAR interactions. While KDM5A is a well-known transcriptional regulator, its function in DNA repair is only now emerging. Here we review the molecular mechanisms that regulate this PARP1-macroH2A1.2-KDM5A axis in DNA damage and consider the potential involvement of this pathway in transcription regulation and cancer. Using KDM5A as an example, we discuss how multifunctional chromatin proteins transition between several DNA-based processes, which must be coordinated to protect the integrity of the genome and epigenome. The dysregulation of chromatin and loss of genome integrity that is prevalent in human diseases including cancer may be related and could provide opportunities to target multitasking proteins with these pathways as therapeutic strategies.
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Affiliation(s)
- Anthony Sanchez
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, The University of Texas at Austin, Austin, Texas, USA
| | | | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, The University of Texas at Austin, Austin, Texas, USA.,Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA
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5
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Kaiser C, Bradu A, Gamble N, Caldwell JA, Koh AS. AIRE in context: Leveraging chromatin plasticity to trigger ectopic gene expression. Immunol Rev 2022; 305:59-76. [PMID: 34545959 PMCID: PMC9250823 DOI: 10.1111/imr.13026] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 08/26/2021] [Indexed: 12/22/2022]
Abstract
The emergence of antigen receptor diversity in clonotypic lymphocytes drove the evolution of a novel gene, Aire, that enabled the adaptive immune system to discriminate foreign invaders from self-constituents. AIRE functions in the epithelial cells of the thymus to express genes highly restricted to alternative cell lineages. This somatic plasticity facilitates the selection of a balanced repertoire of T cells that protects the host from harmful self-reactive clones, yet maintains a wide range of affinities for virtually any foreign antigen. Here, we review the latest understanding of AIRE's molecular actions with a focus on its interplay with chromatin. We argue that AIRE is a multi-valent chromatin effector that acts late in the transcription cycle to modulate the activity of previously poised non-coding regulatory elements of tissue-specific genes. We postulate a role for chromatin instability-caused in part by ATP-dependent chromatin remodeling-that variably sets the scope of the accessible landscape on which AIRE can act. We highlight AIRE's intrinsic repressive function and its relevance in providing feedback control. We synthesize these recent advances into a putative model for the mechanistic modes by which AIRE triggers ectopic transcription for immune repertoire selection.
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Affiliation(s)
- Caroline Kaiser
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
- Department of Human Genetics, University of Chicago, Chicago, Illinois, USA
| | - Alexandra Bradu
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
| | - Noah Gamble
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
- Graduate Program in Biophysical Sciences, University of Chicago, Chicago, Illinois, USA
| | - Jason A. Caldwell
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
| | - Andrew S. Koh
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
- Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
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6
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Manjón AG, Linder S, Teunissen H, Friskes A, Zwart W, de Wit E, Medema RH. Unexpected gene activation following CRISPR-Cas9-mediated genome editing. EMBO Rep 2021; 23:e53902. [PMID: 34927791 PMCID: PMC8811649 DOI: 10.15252/embr.202153902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 12/26/2022] Open
Abstract
The discovery of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and its development as a genome editing tool has revolutionized the field of molecular biology. In the DNA damage field, CRISPR has brought an alternative to induce endogenous double-strand breaks (DSBs) at desired genomic locations and study the DNA damage response and its consequences. Many systems for sgRNA delivery have been reported in order to efficiently generate this DSB, including lentiviral vectors. However, some of the consequences of these systems are not yet well understood. Here, we report that lentiviral-based sgRNA vectors can integrate into the endogenous genomic target location, leading to undesired activation of the target gene. By generating a DSB in the regulatory region of the ABCB1 gene using a lentiviral sgRNA vector, we can induce the formation of Taxol-resistant colonies. We show that these colonies upregulate ABCB1 via integration of the EEF1A1 and the U6 promoters from the sgRNA vector. We believe that this is an unreported CRISPR/Cas9 on-target effect that researchers need to be aware of when using lentiviral vectors for genome editing.
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Affiliation(s)
- Anna G Manjón
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Simon Linder
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Hans Teunissen
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Anoek Friskes
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wilbert Zwart
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Elzo de Wit
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - René H Medema
- Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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7
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Spegg V, Altmeyer M. Biomolecular condensates at sites of DNA damage: More than just a phase. DNA Repair (Amst) 2021; 106:103179. [PMID: 34311273 PMCID: PMC7612016 DOI: 10.1016/j.dnarep.2021.103179] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 12/12/2022]
Abstract
Protein recruitment to DNA break sites is an integral part of the DNA damage response (DDR). Elucidation of the hierarchy and temporal order with which DNA damage sensors as well as repair and signaling factors assemble around chromosome breaks has painted a complex picture of tightly regulated macromolecular interactions that build specialized compartments to facilitate repair and maintenance of genome integrity. While many of the underlying interactions, e.g. between repair factors and damage-induced histone marks, can be explained by lock-and-key or induced fit binding models assuming fixed stoichiometries, structurally less well defined interactions, such as the highly dynamic multivalent interactions implicated in phase separation, also participate in the formation of multi-protein assemblies in response to genotoxic stress. Although much remains to be learned about these types of cooperative and highly dynamic interactions and their functional roles, the rapidly growing interest in material properties of biomolecular condensates and in concepts from polymer chemistry and soft matter physics to understand biological processes at different scales holds great promises. Here, we discuss nuclear condensates in the context of genome integrity maintenance, highlighting the cooperative potential between clustered stoichiometric binding and phase separation. Rather than viewing them as opposing scenarios, their combined effects can balance structural specificity with favorable physicochemical properties relevant for the regulation and function of multilayered nuclear condensates.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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8
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Stanic M, Mekhail K. Integration of DNA damage responses with dynamic spatial genome organization. Trends Genet 2021; 38:290-304. [PMID: 34598804 DOI: 10.1016/j.tig.2021.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/26/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
The maintenance of genome stability and cellular homeostasis depends on the temporal and spatial coordination of successive events constituting the classical DNA damage response (DDR). Recent findings suggest close integration and coordination of DDR signaling with specific cellular processes. The mechanisms underlying such coordination remain unclear. We review emerging crosstalk between DNA repair factors, chromatin remodeling, replication, transcription, spatial genome organization, cytoskeletal forces, and liquid-liquid phase separation (LLPS) in mediating DNA repair. We present an overarching DNA repair framework within which these dynamic processes intersect in nuclear space over time. Collectively, this interplay ensures the efficient assembly of DNA repair proteins onto shifting genome structures to preserve genome stability and cell survival.
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Affiliation(s)
- Mia Stanic
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, MaRS Centre, West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, MaRS Centre, West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Canada Research Chairs Program, Temerty Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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9
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Lloyd R, Urban V, Muñoz-Martínez F, Ayestaran I, Thomas J, de Renty C, O’Connor M, Forment J, Galanty Y, Jackson S. Loss of Cyclin C or CDK8 provides ATR inhibitor resistance by suppressing transcription-associated replication stress. Nucleic Acids Res 2021; 49:8665-8683. [PMID: 34329458 PMCID: PMC8421211 DOI: 10.1093/nar/gkab628] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/04/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
The protein kinase ATR plays pivotal roles in DNA repair, cell cycle checkpoint engagement and DNA replication. Consequently, ATR inhibitors (ATRi) are in clinical development for the treatment of cancers, including tumours harbouring mutations in the related kinase ATM. However, it still remains unclear which functions and pathways dominate long-term ATRi efficacy, and how these vary between clinically relevant genetic backgrounds. Elucidating common and genetic-background specific mechanisms of ATRi efficacy could therefore assist in patient stratification and pre-empting drug resistance. Here, we use CRISPR-Cas9 genome-wide screening in ATM-deficient and proficient mouse embryonic stem cells to interrogate cell fitness following treatment with the ATRi, ceralasertib. We identify factors that enhance or suppress ATRi efficacy, with a subset of these requiring intact ATM signalling. Strikingly, two of the strongest resistance-gene hits in both ATM-proficient and ATM-deficient cells encode Cyclin C and CDK8: members of the CDK8 kinase module for the RNA polymerase II mediator complex. We show that Cyclin C/CDK8 loss reduces S-phase DNA:RNA hybrid formation, transcription-replication stress, and ultimately micronuclei formation induced by ATRi. Overall, our work identifies novel biomarkers of ATRi efficacy in ATM-proficient and ATM-deficient cells, and highlights transcription-associated replication stress as a predominant driver of ATRi-induced cell death.
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Affiliation(s)
- Rebecca L Lloyd
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
| | - Vaclav Urban
- Bioscience, Oncology R&D, AstraZeneca, Cambridge, UK
| | - Francisco Muñoz-Martínez
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
| | - Iñigo Ayestaran
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
| | - John C Thomas
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
| | | | | | | | - Yaron Galanty
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
| | - Stephen P Jackson
- Wellcome/Cancer Research UK Gurdon Institute, and Department of Biochemistry, University of Cambridge, UK
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10
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Nandakumar S, Rozich E, Buttitta L. Cell Cycle Re-entry in the Nervous System: From Polyploidy to Neurodegeneration. Front Cell Dev Biol 2021; 9:698661. [PMID: 34249947 PMCID: PMC8264763 DOI: 10.3389/fcell.2021.698661] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 05/19/2021] [Indexed: 12/15/2022] Open
Abstract
Terminally differentiated cells of the nervous system have long been considered to be in a stable non-cycling state and are often considered to be permanently in G0. Exit from the cell cycle during development is often coincident with the differentiation of neurons, and is critical for neuronal function. But what happens in long lived postmitotic tissues that accumulate cell damage or suffer cell loss during aging? In other contexts, cells that are normally non-dividing or postmitotic can or re-enter the cell cycle and begin replicating their DNA to facilitate cellular growth in response to cell loss. This leads to a state called polyploidy, where cells contain multiple copies of the genome. A growing body of literature from several vertebrate and invertebrate model organisms has shown that polyploidy in the nervous system may be more common than previously appreciated and occurs under normal physiological conditions. Moreover, it has been found that neuronal polyploidization can play a protective role when cells are challenged with DNA damage or oxidative stress. By contrast, work over the last two and a half decades has discovered a link between cell-cycle reentry in neurons and several neurodegenerative conditions. In this context, neuronal cell cycle re-entry is widely considered to be aberrant and deleterious to neuronal health. In this review, we highlight historical and emerging reports of polyploidy in the nervous systems of various vertebrate and invertebrate organisms. We discuss the potential functions of polyploidization in the nervous system, particularly in the context of long-lived cells and age-associated polyploidization. Finally, we attempt to reconcile the seemingly disparate associations of neuronal polyploidy with both neurodegeneration and neuroprotection.
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Affiliation(s)
| | | | - Laura Buttitta
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
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11
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Perfecting DNA double-strand break repair on transcribed chromatin. Essays Biochem 2021; 64:705-719. [PMID: 32309851 DOI: 10.1042/ebc20190094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 02/07/2023]
Abstract
Timely repair of DNA double-strand break (DSB) entails coordination with the local higher order chromatin structure and its transaction activities, including transcription. Recent studies are uncovering how DSBs trigger transient suppression of nearby transcription to permit faithful DNA repair, failing of which leads to elevated chromosomal aberrations and cell hypersensitivity to DNA damage. Here, we summarize the molecular bases for transcriptional control during DSB metabolism, and discuss how the exquisite coordination between the two DNA-templated processes may underlie maintenance of genome stability and cell homeostasis.
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12
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Mohanan G, Das A, Rajyaguru PI. Genotoxic stress response: What is the role of cytoplasmic mRNA fate? Bioessays 2021; 43:e2000311. [PMID: 34096096 DOI: 10.1002/bies.202000311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 05/15/2021] [Accepted: 05/18/2021] [Indexed: 12/18/2022]
Abstract
Genotoxic stress leads to DNA damage which can be detrimental to the cell. A well-orchestrated cellular response is mounted to manage and repair the genotoxic stress-induced DNA damage. Our understanding of genotoxic stress response is derived mainly from studies focused on transcription, mRNA splicing, and protein turnover. Surprisingly not as much is understood about the role of mRNA translation and decay in genotoxic stress response. This is despite the fact that regulation of gene expression at the level of mRNA translation and decay plays a critical role in a myriad of cellular processes. This review aims to summarize some of the known findings of the role of mRNA translation and decay by focusing on two categories of examples. We discuss examples of mRNA whose fates are regulated in the cytoplasm and RNA-binding proteins that regulate mRNA fates in response to genotoxic stress.
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Affiliation(s)
- Gayatri Mohanan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Amiyaranjan Das
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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13
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Levone BR, Lenzken SC, Antonaci M, Maiser A, Rapp A, Conte F, Reber S, Mechtersheimer J, Ronchi AE, Mühlemann O, Leonhardt H, Cardoso MC, Ruepp MD, Barabino SM. FUS-dependent liquid-liquid phase separation is important for DNA repair initiation. J Cell Biol 2021; 220:e202008030. [PMID: 33704371 PMCID: PMC7953258 DOI: 10.1083/jcb.202008030] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 01/17/2021] [Accepted: 02/04/2021] [Indexed: 12/17/2022] Open
Abstract
RNA-binding proteins (RBPs) are emerging as important effectors of the cellular DNA damage response (DDR). The RBP FUS is implicated in RNA metabolism and DNA repair, and it undergoes reversible liquid-liquid phase separation (LLPS) in vitro. Here, we demonstrate that FUS-dependent LLPS is necessary for the initiation of the DDR. Using laser microirradiation in FUS-knockout cells, we show that FUS is required for the recruitment to DNA damage sites of the DDR factors KU80, NBS1, and 53BP1 and of SFPQ, another RBP implicated in the DDR. The relocation of KU80, NBS1, and SFPQ is similarly impaired by LLPS inhibitors, or LLPS-deficient FUS variants. We also show that LLPS is necessary for efficient γH2AX foci formation. Finally, using superresolution structured illumination microscopy, we demonstrate that the absence of FUS impairs the proper arrangement of γH2AX nanofoci into higher-order clusters. These findings demonstrate the early requirement for FUS-dependent LLPS in the activation of the DDR and the proper assembly of DSB repair complexes.
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Affiliation(s)
- Brunno R. Levone
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Silvia C. Lenzken
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Marco Antonaci
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Andreas Maiser
- Department of Biology II, Center for Integrated Protein Science Munich, Ludwig Maximilian University of Munich, Planegg-Martinsried, Germany
| | - Alexander Rapp
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Francesca Conte
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Stefan Reber
- UK Dementia Research Institute, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Jonas Mechtersheimer
- UK Dementia Research Institute, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Antonella E. Ronchi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Heinrich Leonhardt
- Department of Biology II, Center for Integrated Protein Science Munich, Ludwig Maximilian University of Munich, Planegg-Martinsried, Germany
| | - M. Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Marc-David Ruepp
- UK Dementia Research Institute, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Silvia M.L. Barabino
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
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14
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Long Q, Liu Z, Gullerova M. Sweet Melody or Jazz? Transcription Around DNA Double-Strand Breaks. Front Mol Biosci 2021; 8:655786. [PMID: 33959637 PMCID: PMC8096065 DOI: 10.3389/fmolb.2021.655786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/22/2021] [Indexed: 12/23/2022] Open
Abstract
Genomic integrity is continuously threatened by thousands of endogenous and exogenous damaging factors. To preserve genome stability, cells developed comprehensive DNA damage response (DDR) pathways that mediate the recognition of damaged DNA lesions, the activation of signaling cascades, and the execution of DNA repair. Transcription has been understood to pose a threat to genome stability in the presence of DNA breaks. Interestingly, accumulating evidence in recent years shows that the transient transcriptional activation at DNA double-strand break (DSB) sites is required for efficient repair, while the rest of the genome exhibits temporary transcription silencing. This genomic shut down is a result of multiple signaling cascades involved in the maintenance of DNA/RNA homeostasis, chromatin stability, and genome fidelity. The regulation of transcription of protein-coding genes and non-coding RNAs has been extensively studied; however, the exact regulatory mechanisms of transcription at DSBs remain enigmatic. These complex processes involve many players such as transcription-associated protein complexes, including kinases, transcription factors, chromatin remodeling complexes, and helicases. The damage-derived transcripts themselves also play an essential role in DDR regulation. In this review, we summarize the current findings on the regulation of transcription at DSBs and discussed the roles of various accessory proteins in these processes and consequently in DDR.
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Affiliation(s)
| | | | - Monika Gullerova
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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15
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R-loops as Janus-faced modulators of DNA repair. Nat Cell Biol 2021; 23:305-313. [PMID: 33837288 DOI: 10.1038/s41556-021-00663-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/05/2021] [Indexed: 02/01/2023]
Abstract
R-loops are non-B DNA structures with intriguing dual consequences for gene expression and genome stability. In addition to their recognized roles in triggering DNA double-strand breaks (DSBs), R-loops have recently been demonstrated to accumulate in cis to DSBs, especially those induced in transcriptionally active loci. In this Review, we discuss whether R-loops actively participate in DSB repair or are detrimental by-products that must be removed to avoid genome instability.
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16
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The Role of Polycomb Group Protein BMI1 in DNA Repair and Genomic Stability. Int J Mol Sci 2021; 22:ijms22062976. [PMID: 33804165 PMCID: PMC7998361 DOI: 10.3390/ijms22062976] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/09/2021] [Indexed: 12/31/2022] Open
Abstract
The polycomb group (PcG) proteins are a class of transcriptional repressors that mediate gene silencing through histone post-translational modifications. They are involved in the maintenance of stem cell self-renewal and proliferation, processes that are often dysregulated in cancer. Apart from their canonical functions in epigenetic gene silencing, several studies have uncovered a function for PcG proteins in DNA damage signaling and repair. In particular, members of the poly-comb group complexes (PRC) 1 and 2 have been shown to recruit to sites of DNA damage and mediate DNA double-strand break repair. Here, we review current understanding of the PRCs and their roles in cancer development. We then focus on the PRC1 member BMI1, discussing the current state of knowledge of its role in DNA repair and genome integrity, and outline how it can be targeted pharmacologically.
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17
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Sato M, Liebau RC, Liu Z, Liu L, Rabadan R, Gautier J. The UVSSA complex alleviates MYC-driven transcription stress. J Cell Biol 2021; 220:e201807163. [PMID: 33404608 PMCID: PMC7791342 DOI: 10.1083/jcb.201807163] [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: 11/05/2018] [Revised: 10/05/2020] [Accepted: 11/25/2020] [Indexed: 01/05/2023] Open
Abstract
Cancer cells develop strong genetic dependencies, enabling survival under oncogenic stress. MYC is a key oncogene activated across most cancers, and identifying associated synthetic lethality or sickness can provide important clues about its activity and potential therapeutic strategies. On the basis of previously conducted genome-wide screenings in MCF10A cells expressing MYC fused to an estrogen receptor fragment, we identified UVSSA, a gene involved in transcription-coupled repair, whose knockdown or knockout decreased cell viability when combined with MYC expression. Synthetic sick interactions between MYC expression and UVSSA down-regulation correlated with ATM/CHK2 activation, suggesting increased genome instability. We show that the synthetic sick interaction is diminished by attenuating RNA polymerase II (RNAPII) activity; yet, it is independent of UV-induced damage repair, suggesting that UVSSA has a critical function in regulating RNAPII in the absence of exogenous DNA damage. Supporting this hypothesis, RNAPII ChIP-seq revealed that MYC-dependent increases in RNAPII promoter occupancy are reduced or abrogated by UVSSA knockdown, suggesting that UVSSA influences RNAPII dynamics during MYC-dependent transcription. Taken together, our data show that the UVSSA complex has a significant function in supporting MYC-dependent RNAPII dynamics and maintaining cell survival during MYC addiction. While the role of UVSSA in regulating RNAPII has been documented thus far only in the context of UV-induced DNA damage repair, we propose that its activity is also required to cope with transcriptional changes induced by oncogene activation.
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Affiliation(s)
- Mai Sato
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY
| | - Rowyn C. Liebau
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY
- Department of Biology, Columbia University, New York, NY
| | - Zhaoqi Liu
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, China National Center for Bioinformation, Beijing, China
- Program for Mathematical Genomics, Departments of Systems Biology and Biomedical Informatics, Columbia University, New York, NY
| | - Lizhi Liu
- Department of Biology, Columbia University, New York, NY
| | - Raul Rabadan
- Program for Mathematical Genomics, Departments of Systems Biology and Biomedical Informatics, Columbia University, New York, NY
| | - Jean Gautier
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY
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18
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Sharma S, Anand R, Zhang X, Francia S, Michelini F, Galbiati A, Williams H, Ronato DA, Masson JY, Rothenberg E, Cejka P, d'Adda di Fagagna F. MRE11-RAD50-NBS1 Complex Is Sufficient to Promote Transcription by RNA Polymerase II at Double-Strand Breaks by Melting DNA Ends. Cell Rep 2021; 34:108565. [PMID: 33406426 PMCID: PMC7788559 DOI: 10.1016/j.celrep.2020.108565] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/19/2020] [Accepted: 12/07/2020] [Indexed: 12/24/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) complex supports the synthesis of damage-induced long non-coding RNA (dilncRNA) by RNA polymerase II (RNAPII) from DNA double-strand breaks (DSBs) by an unknown mechanism. Here, we show that recombinant human MRN and native RNAPII are sufficient to reconstitute a minimal functional transcriptional apparatus at DSBs. MRN recruits and stabilizes RNAPII at DSBs. Unexpectedly, transcription is promoted independently from MRN nuclease activities. Rather, transcription depends on the ability of MRN to melt DNA ends, as shown by the use of MRN mutants and specific allosteric inhibitors. Single-molecule FRET assays with wild-type and mutant MRN show a tight correlation between the ability to melt DNA ends and to promote transcription. The addition of RPA enhances MRN-mediated transcription, and unpaired DNA ends allow MRN-independent transcription by RNAPII. These results support a model in which MRN generates single-strand DNA ends that favor the initiation of transcription by RNAPII.
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Affiliation(s)
- Sheetal Sharma
- IFOM-The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Roopesh Anand
- Institute for Research in Biomedicine, Università della Svizzera Italiana (USI), Faculty of Biomedical Sciences, Bellinzona 6500, Switzerland
| | - Xuzhu Zhang
- NYU Langone Medical Center, 450 East 29th Street, New York, NY, USA
| | - Sofia Francia
- IFOM-The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Istituto di Genetica Molecolare, CNR-Consiglio Nazionale delle Ricerche, Pavia 2700, Italy
| | - Flavia Michelini
- IFOM-The FIRC Institute of Molecular Oncology, Milan 20139, Italy
| | | | | | - Daryl A Ronato
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Axis, 9 McMahon, Québec City, QC G1R 2J6, Canada; Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec City, QC G1R 2J6, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Axis, 9 McMahon, Québec City, QC G1R 2J6, Canada; Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec City, QC G1R 2J6, Canada
| | - Eli Rothenberg
- NYU Langone Medical Center, 450 East 29th Street, New York, NY, USA
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera Italiana (USI), Faculty of Biomedical Sciences, Bellinzona 6500, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland.
| | - Fabrizio d'Adda di Fagagna
- IFOM-The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Istituto di Genetica Molecolare, CNR-Consiglio Nazionale delle Ricerche, Pavia 2700, Italy.
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19
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Global Genome Demethylation Causes Transcription-Associated DNA Double Strand Breaks in HPV-Associated Head and Neck Cancer Cells. Cancers (Basel) 2020; 13:cancers13010021. [PMID: 33374558 PMCID: PMC7793113 DOI: 10.3390/cancers13010021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023] Open
Abstract
High levels of DNA methylation at CpG loci are associated with transcriptional repression of tumor suppressor genes and dysregulation of DNA repair genes. Human papilloma virus (HPV)-associated head and neck squamous cell carcinomas (HNSCC) have high levels of DNA methylation and methylation has been associated with dampening of an innate immune response in virally infected cells. We have been exploring demethylation as a potential treatment in HPV+ HNSCC and recently reported results of a window clinical trial showing that HNSCCs are particularly sensitive to demethylating agent 5-azacytidine (5-aza). Mechanistically, sensitivity is partially due to downregulation of HPV genes expression and restoration of tumor suppressors p53 and Rb. Here, for the first time, we show that 5-azaC treatment of HPV+ HNSCC induces replication and transcription-associated DNA double strand breaks (DSBs) that occur preferentially at demethylated genomic DNA. Blocking replication or transcription prevented formation of DNA DSBs and reduced sensitivity of HPV-positive head and neck cancer cells to 5-azaC, demonstrating that both replication and active transcription are required for formation of DSBs associated with 5-azaC.
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20
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Giannini M, Bayona-Feliu A, Sproviero D, Barroso SI, Cereda C, Aguilera A. TDP-43 mutations link Amyotrophic Lateral Sclerosis with R-loop homeostasis and R loop-mediated DNA damage. PLoS Genet 2020; 16:e1009260. [PMID: 33301444 PMCID: PMC7755276 DOI: 10.1371/journal.pgen.1009260] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 12/22/2020] [Accepted: 11/08/2020] [Indexed: 12/16/2022] Open
Abstract
TDP-43 is a DNA and RNA binding protein involved in RNA processing and with structural resemblance to heterogeneous ribonucleoproteins (hnRNPs), whose depletion sensitizes neurons to double strand DNA breaks (DSBs). Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder, in which 97% of patients are familial and sporadic cases associated with TDP-43 proteinopathies and conditions clearing TDP-43 from the nucleus, but we know little about the molecular basis of the disease. After showing with the non-neuronal model of HeLa cells that TDP-43 depletion increases R loops and associated genome instability, we prove that mislocalization of mutated TDP-43 (A382T) in transfected neuronal SH-SY5Y and lymphoblastoid cell lines (LCLs) from an ALS patient cause R-loop accumulation, R loop-dependent increased DSBs and Fanconi Anemia repair centers. These results uncover a new role of TDP-43 in the control of co-transcriptional R loops and the maintenance of genome integrity by preventing harmful R-loop accumulation. Our findings thus link TDP-43 pathology to increased R loops and R loop-mediated DNA damage opening the possibility that R-loop modulation in TDP-43-defective cells might help develop ALS therapies. Amyotrophic Lateral Sclerosis (ALS) is an adult onset, progressive neurodegenerative disease, caused by the selective loss of upper and lower motor neurons in the cerebral cortex, brainstem and spinal cord. The nuclear TDP-43 RNA binding protein, is encoded by a major gene for ALS susceptibility whose mutations are found in 3% of familial and 2% of sporadic ALS cases. Thanks to its ability to recognize DNA and RNA, TDP-43 is involved in different steps of mRNA metabolism and in several mechanisms of genome integrity. This, together with the fact that R loops or DNA-RNA hybrids are a common source of genome instability, prompted us to investigate whether TDP-43 deficiency has any role in R loop homeostasis that could explain previously described DNA damage response defects of ALS cells. We show that TDP-43 plays a role in preventing R loop-accumulation and associated genome instability in neuronal and non-neuronal cells, as well as in patient cell lines. Thus, our study opens the possibility that R loop-modulation in TDP-43-defective cells might help develop ALS therapies.
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Affiliation(s)
- Marta Giannini
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Aleix Bayona-Feliu
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Daisy Sproviero
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Sonia I. Barroso
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Cristina Cereda
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
- * E-mail: (CC); (AA)
| | - Andrés Aguilera
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- * E-mail: (CC); (AA)
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21
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The molecular basis and disease relevance of non-homologous DNA end joining. Nat Rev Mol Cell Biol 2020; 21:765-781. [PMID: 33077885 DOI: 10.1038/s41580-020-00297-8] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2020] [Indexed: 12/26/2022]
Abstract
Non-homologous DNA end joining (NHEJ) is the predominant repair mechanism of any type of DNA double-strand break (DSB) during most of the cell cycle and is essential for the development of antigen receptors. Defects in NHEJ result in sensitivity to ionizing radiation and loss of lymphocytes. The most critical step of NHEJ is synapsis, or the juxtaposition of the two DNA ends of a DSB, because all subsequent steps rely on it. Recent findings show that, like the end processing step, synapsis can be achieved through several mechanisms. In this Review, we first discuss repair pathway choice between NHEJ and other DSB repair pathways. We then integrate recent insights into the mechanisms of NHEJ synapsis with updates on other steps of NHEJ, such as DNA end processing and ligation. Finally, we discuss NHEJ-related human diseases, including inherited disorders and neoplasia, which arise from rare failures at different NHEJ steps.
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22
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Sangermano F, Delicato A, Calabrò V. Y box binding protein 1 (YB-1) oncoprotein at the hub of DNA proliferation, damage and cancer progression. Biochimie 2020; 179:205-216. [PMID: 33058958 DOI: 10.1016/j.biochi.2020.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022]
Abstract
The Y Box binding protein 1 (YB-1) belongs to the highly conserved Cold Shock Domain protein family and is a major component of messenger ribonucleoprotein particles (mRNPs) in various organisms and cells. Cold Shock proteins are multifunctional nucleic acids binding proteins involved in a variety of cellular functions. Biological activities of YB-1 range from the regulation of transcription, splicing and translation, to the orchestration of exosomal RNA content. The role of YB-1 in malignant cell transformation and fate transition is the subject of intensive investigation. Besides, emerging evidence indicates that YB-1 participates in several DNA damage repair pathways as a non-canonical DNA repair factor thus pointing out that the protein can allow cancer cells to evade conventional anticancer therapies and avoid cell death. Here, we will attempt to collect and summarize the current knowledge on this subject and provide the basis for further lines of inquiry.
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Affiliation(s)
- Felicia Sangermano
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126, Napoli, Italy.
| | - Antonella Delicato
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126, Napoli, Italy
| | - Viola Calabrò
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126, Napoli, Italy
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23
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Martin JC, Hoegel TJ, Lynch ML, Woloszynska A, Melendy T, Ohm JE. Exploiting Replication Stress as a Novel Therapeutic Intervention. Mol Cancer Res 2020; 19:192-206. [PMID: 33020173 DOI: 10.1158/1541-7786.mcr-20-0651] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/01/2020] [Accepted: 09/29/2020] [Indexed: 11/16/2022]
Abstract
Ewing sarcoma is an aggressive pediatric tumor of the bone and soft tissue. The current standard of care is radiation and chemotherapy, and patients generally lack targeted therapies. One of the defining molecular features of this tumor type is the presence of significantly elevated levels of replication stress as compared with both normal cells and many other types of cancers, but the source of this stress is poorly understood. Tumors that harbor elevated levels of replication stress rely on the replication stress and DNA damage response pathways to retain viability. Understanding the source of the replication stress in Ewing sarcoma may reveal novel therapeutic targets. Ewing sarcomagenesis is complex, and in this review, we discuss the current state of our knowledge regarding elevated replication stress and the DNA damage response in Ewing sarcoma, one contributor to the disease process. We will also describe how these pathways are being successfully targeted therapeutically in other tumor types, and discuss possible novel, evidence-based therapeutic interventions in Ewing sarcoma. We hope that this consolidation will spark investigations that uncover new therapeutic targets and lead to the development of better treatment options for patients with Ewing sarcoma. IMPLICATIONS: This review uncovers new therapeutic targets in Ewing sarcoma and highlights replication stress as an exploitable vulnerability across multiple cancers.
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Affiliation(s)
- Jeffrey C Martin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Tamara J Hoegel
- Department of Pediatric Hematology and Oncology, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Miranda L Lynch
- Hauptman-Woodward Medical Research Institute, Buffalo, New York
| | - Anna Woloszynska
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Thomas Melendy
- Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York
| | - Joyce E Ohm
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
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24
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Szlachta K, Manukyan A, Raimer HM, Singh S, Salamon A, Guo W, Lobachev KS, Wang YH. Topoisomerase II contributes to DNA secondary structure-mediated double-stranded breaks. Nucleic Acids Res 2020; 48:6654-6671. [PMID: 32501506 PMCID: PMC7337936 DOI: 10.1093/nar/gkaa483] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/20/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double-stranded breaks (DSBs) trigger human genome instability, therefore identifying what factors contribute to DSB induction is critical for our understanding of human disease etiology. Using an unbiased, genome-wide approach, we found that genomic regions with the ability to form highly stable DNA secondary structures are enriched for endogenous DSBs in human cells. Human genomic regions predicted to form non-B-form DNA induced gross chromosomal rearrangements in yeast and displayed high indel frequency in human genomes. The extent of instability in both analyses is in concordance with the structure forming ability of these regions. We also observed an enrichment of DNA secondary structure-prone sites overlapping transcription start sites (TSSs) and CCCTC-binding factor (CTCF) binding sites, and uncovered an increase in DSBs at highly stable DNA secondary structure regions, in response to etoposide, an inhibitor of topoisomerase II (TOP2) re-ligation activity. Importantly, we found that TOP2 deficiency in both yeast and human leads to a significant reduction in DSBs at structure-prone loci, and that sites of TOP2 cleavage have a greater ability to form highly stable DNA secondary structures. This study reveals a direct role for TOP2 in generating secondary structure-mediated DNA fragility, advancing our understanding of mechanisms underlying human genome instability.
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Affiliation(s)
- Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Arkadi Manukyan
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Heather M Raimer
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Sandeep Singh
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Anita Salamon
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Wenying Guo
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Kirill S Lobachev
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
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25
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Dong C, West KL, Tan XY, Li J, Ishibashi T, Yu CH, Sy SMH, Leung JWC, Huen MSY. Screen identifies DYRK1B network as mediator of transcription repression on damaged chromatin. Proc Natl Acad Sci U S A 2020; 117:17019-17030. [PMID: 32611815 PMCID: PMC7382216 DOI: 10.1073/pnas.2002193117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DNA double-strand breaks (DSBs) trigger transient pausing of nearby transcription, an emerging ATM-dependent response that suppresses chromosomal instability. We screened a chemical library designed to target the human kinome for new activities that mediate gene silencing on DSB-flanking chromatin, and have uncovered the DYRK1B kinase as an early respondent to DNA damage. We showed that DYRK1B is swiftly and transiently recruited to laser-microirradiated sites, and that genetic inactivation of DYRK1B or its kinase activity attenuated DSB-induced gene silencing and led to compromised DNA repair. Notably, global transcription shutdown alleviated DNA repair defects associated with DYRK1B loss, suggesting that DYRK1B is strictly required for DSB repair on active chromatin. We also found that DYRK1B mediates transcription silencing in part via phosphorylating and enforcing DSB accumulation of the histone methyltransferase EHMT2. Together, our findings unveil the DYRK1B signaling network as a key branch of mammalian DNA damage response circuitries, and establish the DYRK1B-EHMT2 axis as an effector that coordinates DSB repair on transcribed chromatin.
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Affiliation(s)
- Chao Dong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Kirk L West
- Department of Radiation Oncology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Xin Yi Tan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Junshi Li
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Toyotaka Ishibashi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong SAR, China
| | - Cheng-Han Yu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Shirley M H Sy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Justin W C Leung
- Department of Radiation Oncology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205;
| | - Michael S Y Huen
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China;
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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26
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Mitrentsi I, Yilmaz D, Soutoglou E. How to maintain the genome in nuclear space. Curr Opin Cell Biol 2020; 64:58-66. [PMID: 32220808 DOI: 10.1016/j.ceb.2020.02.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/28/2020] [Accepted: 02/23/2020] [Indexed: 01/27/2023]
Abstract
Genomic instability can be life-threatening. The fine balance between error-free and mutagenic DNA repair pathways is essential for maintaining genome integrity. Recent advances in DNA double-strand break induction and detection techniques have allowed the investigation of DNA damage and repair in the context of the highly complex nuclear structure. These studies have revealed that the 3D genome folding, nuclear compartmentalization and cytoskeletal components control the spatial distribution of DNA lesions within the nuclear space and dictate their mode of repair.
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Affiliation(s)
- Ioanna Mitrentsi
- Institut de Génétique et de Biologie Moléculaire et Celullaire, 67404, Illkirch, France; Institut National de La Santé et de La Recherche Médicale, U964, 67404, Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404, Illkirch, France; Université de Strasbourg, 67081, Strasbourg, France
| | - Duygu Yilmaz
- Institut de Génétique et de Biologie Moléculaire et Celullaire, 67404, Illkirch, France; Institut National de La Santé et de La Recherche Médicale, U964, 67404, Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404, Illkirch, France; Université de Strasbourg, 67081, Strasbourg, France
| | - Evi Soutoglou
- Institut de Génétique et de Biologie Moléculaire et Celullaire, 67404, Illkirch, France; Institut National de La Santé et de La Recherche Médicale, U964, 67404, Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404, Illkirch, France; Université de Strasbourg, 67081, Strasbourg, France.
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27
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Singh S, Szlachta K, Manukyan A, Raimer HM, Dinda M, Bekiranov S, Wang YH. Pausing sites of RNA polymerase II on actively transcribed genes are enriched in DNA double-stranded breaks. J Biol Chem 2020; 295:3990-4000. [PMID: 32029477 DOI: 10.1074/jbc.ra119.011665] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/05/2020] [Indexed: 12/16/2022] Open
Abstract
DNA double-stranded breaks (DSBs) are strongly associated with active transcription, and promoter-proximal pausing of RNA polymerase II (Pol II) is a critical step in transcriptional regulation. Mapping the distribution of DSBs along actively expressed genes and identifying the location of DSBs relative to pausing sites can provide mechanistic insights into transcriptional regulation. Using genome-wide DNA break mapping/sequencing techniques at single-nucleotide resolution in human cells, we found that DSBs are preferentially located around transcription start sites of highly transcribed and paused genes and that Pol II promoter-proximal pausing sites are enriched in DSBs. We observed that DSB frequency at pausing sites increases as the strength of pausing increases, regardless of whether the pausing sites are near or far from annotated transcription start sites. Inhibition of topoisomerase I and II by camptothecin and etoposide treatment, respectively, increased DSBs at the pausing sites as the concentrations of drugs increased, demonstrating the involvement of topoisomerases in DSB generation at the pausing sites. DNA breaks generated by topoisomerases are short-lived because of the religation activity of these enzymes, which these drugs inhibit; therefore, the observation of increased DSBs with increasing drug doses at pausing sites indicated active recruitment of topoisomerases to these sites. Furthermore, the enrichment and locations of DSBs at pausing sites were shared among different cell types, suggesting that Pol II promoter-proximal pausing is a common regulatory mechanism. Our findings support a model in which topoisomerases participate in Pol II promoter-proximal pausing and indicated that DSBs at pausing sites contribute to transcriptional activation.
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Affiliation(s)
- Sandeep Singh
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Arkadi Manukyan
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Heather M Raimer
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Manikarna Dinda
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Stefan Bekiranov
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
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28
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Szlachta K, Raimer HM, Comeau LD, Wang YH. CNCC: an analysis tool to determine genome-wide DNA break end structure at single-nucleotide resolution. BMC Genomics 2020; 21:25. [PMID: 31914926 PMCID: PMC6950916 DOI: 10.1186/s12864-019-6436-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/26/2019] [Indexed: 12/11/2022] Open
Abstract
Background DNA double-stranded breaks (DSBs) are potentially deleterious events in a cell. The end structures (blunt, 3′- and 5′-overhangs) at DSB sites contribute to the fate of their repair and provide critical information concerning the consequences of the damage. Therefore, there has been a recent eruption of DNA break mapping and sequencing methods that aim to map at single-nucleotide resolution where breaks are generated genome-wide. These methods provide high resolution data for the location of DSBs, which can encode the type of end-structure present at these breaks. However, genome-wide analysis of the resulting end structures has not been investigated following these sequencing methods. Results To address this analysis gap, we develop the use of a coverage-normalized cross correlation analysis (CNCC) to process the high-precision genome-wide break mapping data, and determine genome-wide break end structure distributions at single-nucleotide resolution. We take advantage of the single-nucleotide position and the knowledge of strandness from every mapped break to analyze the relative shifts between positive and negative strand encoded break nucleotides. By applying CNCC we can identify the most abundant end structures captured by a break mapping technique, and further can make comparisons between different samples and treatments. We validate our analysis with restriction enzyme digestions of genomic DNA and establish the sensitivity of the analysis using end structures that only exist as a minor fraction of total breaks. Finally, we demonstrate the versatility of our analysis by applying CNCC to the breaks resulting after treatment with etoposide and study the variety of resulting end structures. Conclusion For the first time, on a genome-wide scale, our analysis revealed the increase in the 5′ to 3′ end resection following etoposide treatment, and the global progression of the resection. Furthermore, our method distinguished the change in the pattern of DSB end structure with increasing doses of the drug. The ability of this method to determine DNA break end structures without a priori knowledge of break sequences or genomic position should have broad applications in understanding genome instability.
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Affiliation(s)
- Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 22903-0733, USA
| | - Heather M Raimer
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 22903-0733, USA
| | - Laurey D Comeau
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 22903-0733, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 22903-0733, USA.
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29
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Sutcu HH, Matta E, Ishchenko AA. Role of PARP-catalyzed ADP-ribosylation in the Crosstalk Between DNA Strand Breaks and Epigenetic Regulation. J Mol Biol 2019:S0022-2836(19)30719-3. [PMID: 31866292 DOI: 10.1016/j.jmb.2019.12.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/29/2019] [Accepted: 12/05/2019] [Indexed: 12/12/2022]
Abstract
Covalent linkage of ADP-ribose units to proteins catalyzed by poly(ADP-ribose) polymerases (PARPs) plays important signaling functions in a plethora of cellular processes including DNA damage response, chromatin organization, and gene transcription. Poly- and mono-ADP-ribosylation of target macromolecules are often responsible both for the initiation and for coordination of these processes in mammalian cells. Currently, the number of cellular targets for ADP-ribosylation is rapidly expanding, and the molecular mechanisms underlying the broad substrate specificity of PARPs present enormous interest. In this review, the roles of PARP-mediated modifications of protein and nucleic acids, the readers of ADP-ribosylated structures, and the origin and function of programmed DNA strand breaks in PARP activation, transcription regulation, and DNA demethylation are discussed.
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Affiliation(s)
- Haser H Sutcu
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Univ. Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France; Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France
| | - Elie Matta
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Univ. Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France; Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France
| | - Alexander A Ishchenko
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR 8200, Univ. Paris-Sud, Université Paris-Saclay, Villejuif, F-94805, France; Gustave Roussy, Université Paris-Saclay, Villejuif, F-94805, France.
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30
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Selective targeting of PARP-2 inhibits androgen receptor signaling and prostate cancer growth through disruption of FOXA1 function. Proc Natl Acad Sci U S A 2019; 116:14573-14582. [PMID: 31266892 DOI: 10.1073/pnas.1908547116] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Androgen receptor (AR) is a ligand-activated transcription factor and a key driver of prostate cancer (PCa) growth and progression. Understanding the factors influencing AR-mediated gene expression provides new opportunities for therapeutic intervention. Poly(ADP-ribose) Polymerase (PARP) is a family of enzymes, which posttranslationally modify a range of proteins and regulate many different cellular processes. PARP-1 and PARP-2 are two well-characterized PARP members, whose catalytic activity is induced by DNA-strand breaks and responsible for multiple DNA damage repair pathways. PARP inhibitors are promising therapeutic agents that show synthetic lethality against many types of cancer (including PCa) with homologous recombination (HR) DNA-repair deficiency. Here, we show that, beyond DNA damage repair function, PARP-2, but not PARP-1, is a critical component in AR transcriptional machinery through interacting with the pioneer factor FOXA1 and facilitating AR recruitment to genome-wide prostate-specific enhancer regions. Analyses of PARP-2 expression at both mRNA and protein levels show significantly higher expression of PARP-2 in primary PCa tumors than in benign prostate tissues, and even more so in castration-resistant prostate cancer (CRPC) tumors. Selective targeting of PARP-2 by genetic or pharmacological means blocks interaction between PARP-2 and FOXA1, which in turn attenuates AR-mediated gene expression and inhibits AR-positive PCa growth. Next-generation antiandrogens act through inhibiting androgen synthesis (abiraterone) or blocking ligand binding (enzalutamide). Selective targeting of PARP-2, however, may provide an alternative therapeutic approach for AR inhibition by disruption of FOXA1 function, which may be beneficial to patients, irrespective of their DNA-repair deficiency status.
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31
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Clouaire T, Legube G. A Snapshot on the Cis Chromatin Response to DNA Double-Strand Breaks. Trends Genet 2019; 35:330-345. [PMID: 30898334 DOI: 10.1016/j.tig.2019.02.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/15/2019] [Accepted: 02/23/2019] [Indexed: 12/11/2022]
Abstract
In eukaryotes, detection and repair of DNA double-strand breaks (DSBs) operate within chromatin, an incredibly complex structure that tightly packages and regulates DNA metabolism. Chromatin participates in the repair of these lesions at multiple steps, from detection to genomic sequence recovery and chromatin is itself extensively modified during the repair process. In recent years, new methodologies and dedicated techniques have expanded the experimental toolbox, opening up a new era granting the high-resolution analysis of chromatin modifications at annotated DSBs in a genome-wide manner. A complex picture is starting to emerge whereby chromatin is altered at various scales around DSBs, in a manner that relates to the repair pathway used, hence defining a 'repair histone code'. Here, we review the recent advances regarding our knowledge of the chromatin landscape induced in cis around DSBs, with an emphasis on histone post-translational modifications and histone variants.
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Affiliation(s)
- Thomas Clouaire
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France.
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32
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Sharma S, di Fagagna FD. In Vitro Detection of Long Noncoding RNA Generated from DNA Double-Strand Breaks. Methods Mol Biol 2019; 2004:209-219. [PMID: 31147920 DOI: 10.1007/978-1-4939-9520-2_16] [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] [Indexed: 06/09/2023]
Abstract
DNA damage response (DDR) is essential for the maintenance of genomic integrity. We have recently discovered the generation of noncoding RNA from a DNA double-strand break (DSB) in an MRE11-RAD50-NBS1 complex-dependent manner, which are necessary for full DDR activation. The low abundance of these noncoding RNA makes them difficult to identify and study. In this chapter, we describe an in vitro biochemical assay to study the generation of damage-induced long noncoding RNA (dilncRNA) from a DNA DSB. In this assay, transcriptionally competent cell-free extracts upon incubation with a linear DNA support RNA synthesis from DNA ends, as monitored by incorporation of 32P[UTP] in discrete products resolved on a denaturing polyacrylamide gel. This approach can be used to identify the role of different DDR proteins in generating dilncRNA.
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Affiliation(s)
- Sheetal Sharma
- IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy.
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
| | - Fabrizio d'Adda di Fagagna
- IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy.
- Istituto di Genetica Molecolare, CNR-Consiglio Nazionale delle Ricerche, Pavia, Italy.
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33
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D'Alessandro G, Whelan DR, Howard SM, Vitelli V, Renaudin X, Adamowicz M, Iannelli F, Jones-Weinert CW, Lee M, Matti V, Lee WTC, Morten MJ, Venkitaraman AR, Cejka P, Rothenberg E, d'Adda di Fagagna F. BRCA2 controls DNA:RNA hybrid level at DSBs by mediating RNase H2 recruitment. Nat Commun 2018; 9:5376. [PMID: 30560944 PMCID: PMC6299093 DOI: 10.1038/s41467-018-07799-2] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/27/2018] [Indexed: 02/02/2023] Open
Abstract
DNA double-strand breaks (DSBs) are toxic DNA lesions, which, if not properly repaired, may lead to genomic instability, cell death and senescence. Damage-induced long non-coding RNAs (dilncRNAs) are transcribed from broken DNA ends and contribute to DNA damage response (DDR) signaling. Here we show that dilncRNAs play a role in DSB repair by homologous recombination (HR) by contributing to the recruitment of the HR proteins BRCA1, BRCA2, and RAD51, without affecting DNA-end resection. In S/G2-phase cells, dilncRNAs pair to the resected DNA ends and form DNA:RNA hybrids, which are recognized by BRCA1. We also show that BRCA2 directly interacts with RNase H2, mediates its localization to DSBs in the S/G2 cell-cycle phase, and controls DNA:RNA hybrid levels at DSBs. These results demonstrate that regulated DNA:RNA hybrid levels at DSBs contribute to HR-mediated repair.
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Affiliation(s)
| | - Donna Rose Whelan
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Sean Michael Howard
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vela 6, Bellinzona, 6500, Switzerland
| | - Valerio Vitelli
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Xavier Renaudin
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XZ, UK
| | - Marek Adamowicz
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RH, UK
| | - Fabio Iannelli
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | | | - MiYoung Lee
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XZ, UK
| | - Valentina Matti
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Wei Ting C Lee
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Michael John Morten
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | | | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vela 6, Bellinzona, 6500, Switzerland
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, Otto-Stern-Weg 3, Zurich, 8093, Switzerland
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Fabrizio d'Adda di Fagagna
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, Pavia, 27100, Italy.
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Bouwman BAM, Crosetto N. Endogenous DNA Double-Strand Breaks during DNA Transactions: Emerging Insights and Methods for Genome-Wide Profiling. Genes (Basel) 2018; 9:E632. [PMID: 30558210 PMCID: PMC6316733 DOI: 10.3390/genes9120632] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) jeopardize genome integrity and can-when repaired unfaithfully-give rise to structural rearrangements associated with cancer. Exogenous agents such as ionizing radiation or chemotherapy can invoke DSBs, but a vast amount of breakage arises during vital endogenous DNA transactions, such as replication and transcription. Additionally, chromatin looping involved in 3D genome organization and gene regulation is increasingly recognized as a possible contributor to DSB events. In this review, we first discuss insights into the mechanisms of endogenous DSB formation, showcasing the trade-off between essential DNA transactions and the intrinsic challenges that these processes impose on genomic integrity. In the second part, we highlight emerging methods for genome-wide profiling of DSBs, and discuss future directions of research that will help advance our understanding of genome-wide DSB formation and repair.
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Affiliation(s)
- Britta A M Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
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35
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Sivaramakrishnan P, Gordon AJE, Halliday JA, Herman C. How Acts of Infidelity Promote DNA Break Repair: Collision and Collusion Between DNA Repair and Transcription. Bioessays 2018; 40:e1800045. [PMID: 30091472 PMCID: PMC6334755 DOI: 10.1002/bies.201800045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/07/2018] [Indexed: 12/20/2022]
Abstract
Transcription is a fundamental cellular process and the first step in gene regulation. Although RNA polymerase (RNAP) is highly processive, in growing cells the progression of transcription can be hindered by obstacles on the DNA template, such as damaged DNA. The authors recent findings highlight a trade-off between transcription fidelity and DNA break repair. While a lot of work has focused on the interaction between transcription and nucleotide excision repair, less is known about how transcription influences the repair of DNA breaks. The authors suggest that when the cell experiences stress from DNA breaks, the control of RNAP processivity affects the balance between preserving transcription integrity and DNA repair. Here, how the conflict between transcription and DNA double-strand break (DSB) repair threatens the integrity of both RNA and DNA are discussed. In reviewing this field, the authors speculate on cellular paradigms where this equilibrium is well sustained, and instances where the maintenance of transcription fidelity is favored over genome stability.
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Affiliation(s)
- Priya Sivaramakrishnan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor College of Medicine, Dan L. Duncan Comprehensive Cancer Center, Houston, TX 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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36
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Human Rad52 Promotes XPG-Mediated R-loop Processing to Initiate Transcription-Associated Homologous Recombination Repair. Cell 2018; 175:558-570.e11. [DOI: 10.1016/j.cell.2018.08.056] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/02/2018] [Accepted: 08/22/2018] [Indexed: 12/22/2022]
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37
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Abstract
R loops are transient three-stranded nucleic acid structures that form physiologically during transcription when a nascent RNA transcript hybridizes with the DNA template strand, leaving a single strand of displaced nontemplate DNA. However, aberrant persistence of R-loops can cause DNA damage by inducing genomic instability. Indeed, evidence has emerged that R-loops might represent a key element in the pathogenesis of human diseases, including cancer, neurodegeneration, and motor neuron disorders. Mutations in genes directly involved in R-loop biology, such as SETX (senataxin), or unstable DNA expansion eliciting R-loop generation, such as C9ORF72 HRE, can cause DNA damage and ultimately result in motor neuron cell death. In this review, we discuss current advancements in this field with a specific focus on motor neuron diseases associated with deregulation of R-loop structures. These mechanisms can represent novel therapeutic targets for these devastating, incurable diseases.
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38
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Strategies for In Vivo Genome Editing in Nondividing Cells. Trends Biotechnol 2018; 36:770-786. [PMID: 29685818 DOI: 10.1016/j.tibtech.2018.03.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/13/2022]
Abstract
Programmable nucleases, including zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9), have enhanced our ability to edit genomes by the sequence-specific generation of double-strand breaks (DSBs) with subsequent homology-directed repair (HDR) of the DSB. However, the efficiency of the HDR pathway is limited in nondividing cells, which encompass most of the cells in the body. Therefore, the HDR-mediated genome-editing approach has limited in vivo applicability. Here, we discuss a mutation type-oriented viewpoint of strategies devised over the past few years to circumvent this problem, along with their possible applications and limitations.
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39
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Michelini F, Jalihal AP, Francia S, Meers C, Neeb ZT, Rossiello F, Gioia U, Aguado J, Jones-Weinert C, Luke B, Biamonti G, Nowacki M, Storici F, Carninci P, Walter NG, d'Adda di Fagagna F. From "Cellular" RNA to "Smart" RNA: Multiple Roles of RNA in Genome Stability and Beyond. Chem Rev 2018; 118:4365-4403. [PMID: 29600857 DOI: 10.1021/acs.chemrev.7b00487] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA biology and genome stability. We start with an account of the emergence of noncoding RNA, and then we discuss the involvement of RNA in DNA damage signaling and repair, telomere maintenance, and genomic rearrangements. We continue with the depiction of single-molecule RNA detection techniques, and we conclude by illustrating the possibilities of RNA modulation in hopes of creating or improving new therapies. The widespread biological functions of RNA have made this molecule a reoccurring theme in basic and translational research, warranting it the transcendence from classically studied "cellular" RNA to "smart" RNA.
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Affiliation(s)
- Flavia Michelini
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | - Ameya P Jalihal
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Sofia Francia
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy.,Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
| | - Chance Meers
- School of Biological Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Zachary T Neeb
- Institute of Cell Biology , University of Bern , Baltzerstrasse 4 , 3012 Bern , Switzerland
| | | | - Ubaldo Gioia
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | - Julio Aguado
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | | | - Brian Luke
- Institute of Developmental Biology and Neurobiology , Johannes Gutenberg University , 55099 Mainz , Germany.,Institute of Molecular Biology (IMB) , 55128 Mainz , Germany
| | - Giuseppe Biamonti
- Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
| | - Mariusz Nowacki
- Institute of Cell Biology , University of Bern , Baltzerstrasse 4 , 3012 Bern , Switzerland
| | - Francesca Storici
- School of Biological Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Piero Carninci
- RIKEN Center for Life Science Technologies , 1-7-22 Suehiro-cho, Tsurumi-ku , Yokohama City , Kanagawa 230-0045 , Japan
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Fabrizio d'Adda di Fagagna
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy.,Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
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Gavish-Izakson M, Velpula BB, Elkon R, Prados-Carvajal R, Barnabas GD, Ugalde AP, Agami R, Geiger T, Huertas P, Ziv Y, Shiloh Y. Nuclear poly(A)-binding protein 1 is an ATM target and essential for DNA double-strand break repair. Nucleic Acids Res 2018; 46:730-747. [PMID: 29253183 PMCID: PMC5778506 DOI: 10.1093/nar/gkx1240] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022] Open
Abstract
The DNA damage response (DDR) is an extensive signaling network that is robustly mobilized by DNA double-strand breaks (DSBs). The primary transducer of the DSB response is the protein kinase, ataxia-telangiectasia, mutated (ATM). Here, we establish nuclear poly(A)-binding protein 1 (PABPN1) as a novel target of ATM and a crucial player in the DSB response. PABPN1 usually functions in regulation of RNA processing and stability. We establish that PABPN1 is recruited to the DDR as a critical regulator of DSB repair. A portion of PABPN1 relocalizes to DSB sites and is phosphorylated on Ser95 in an ATM-dependent manner. PABPN1 depletion sensitizes cells to DSB-inducing agents and prolongs the DSB-induced G2/M cell-cycle arrest, and DSB repair is hampered by PABPN1 depletion or elimination of its phosphorylation site. PABPN1 is required for optimal DSB repair via both nonhomologous end-joining (NHEJ) and homologous recombination repair (HRR), and specifically is essential for efficient DNA-end resection, an initial, key step in HRR. Using mass spectrometry analysis, we capture DNA damage-induced interactions of phospho-PABPN1, including well-established DDR players as well as other RNA metabolizing proteins. Our results uncover a novel ATM-dependent axis in the rapidly growing interface between RNA metabolism and the DDR.
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Affiliation(s)
- Michal Gavish-Izakson
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Bhagya Bhavana Velpula
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ran Elkon
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rosario Prados-Carvajal
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Georgina D Barnabas
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Alejandro Pineiro Ugalde
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Reuven Agami
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Tamar Geiger
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Pablo Huertas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Yael Ziv
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Shiloh
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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41
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Lejart A, Salbert G, Huet S. Cytosine hydroxymethylation by TET enzymes: From the control of gene expression to the regulation of DNA repair mechanisms, and back. AIMS BIOPHYSICS 2018. [DOI: 10.3934/biophy.2018.3.182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Vitelli V, Galbiati A, Iannelli F, Pessina F, Sharma S, d'Adda di Fagagna F. Recent Advancements in DNA Damage-Transcription Crosstalk and High-Resolution Mapping of DNA Breaks. Annu Rev Genomics Hum Genet 2017; 18:87-113. [PMID: 28859573 DOI: 10.1146/annurev-genom-091416-035314] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Until recently, DNA damage arising from physiological DNA metabolism was considered a detrimental by-product for cells. However, an increasing amount of evidence has shown that DNA damage could have a positive role in transcription activation. In particular, DNA damage has been detected in transcriptional elements following different stimuli. These physiological DNA breaks are thought to be instrumental for the correct expression of genomic loci through different mechanisms. In this regard, although a plethora of methods are available to precisely map transcribed regions and transcription start sites, commonly used techniques for mapping DNA breaks lack sufficient resolution and sensitivity to draw a robust correlation between DNA damage generation and transcription. Recently, however, several methods have been developed to map DNA damage at single-nucleotide resolution, thus providing a new set of tools to correlate DNA damage and transcription. Here, we review how DNA damage can positively regulate transcription initiation, the current techniques for mapping DNA breaks at high resolution, and how these techniques can benefit future studies of DNA damage and transcription.
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Affiliation(s)
- Valerio Vitelli
- FIRC Institute of Molecular Oncology (IFOM), Milan 20139, Italy;
| | | | - Fabio Iannelli
- FIRC Institute of Molecular Oncology (IFOM), Milan 20139, Italy;
| | - Fabio Pessina
- FIRC Institute of Molecular Oncology (IFOM), Milan 20139, Italy;
| | - Sheetal Sharma
- FIRC Institute of Molecular Oncology (IFOM), Milan 20139, Italy;
| | - Fabrizio d'Adda di Fagagna
- FIRC Institute of Molecular Oncology (IFOM), Milan 20139, Italy; .,Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (CNR), Pavia 27100, Italy
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43
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Sebastian R, Oberdoerffer P. Transcription-associated events affecting genomic integrity. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160288. [PMID: 28847825 PMCID: PMC5577466 DOI: 10.1098/rstb.2016.0288] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2017] [Indexed: 12/25/2022] Open
Abstract
Accurate maintenance of genomic as well as epigenomic integrity is critical for proper cell and organ function. Continuous exposure to DNA damage is, thus, often associated with malignant transformation and degenerative diseases. A significant, chronic threat to genome integrity lies in the process of transcription, which can result in the formation of potentially harmful RNA : DNA hybrid structures (R-loops) and has been linked to DNA damage accumulation as well as dynamic chromatin reorganization. In sharp contrast, recent evidence suggests that active transcription, the resulting transcripts as well as R-loop formation can play multi-faceted roles in maintaining and restoring genome integrity. Here, we will discuss the emerging contributions of transcription as both a source of DNA damage and a mediator of DNA repair. We propose that both aspects have significant implications for genome maintenance, and will speculate on possible long-term consequences for the epigenetic integrity of transcribing cells.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Robin Sebastian
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Building 41, Room B907, Bethesda, MD 20892, USA
| | - Philipp Oberdoerffer
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Building 41, Room B907, Bethesda, MD 20892, USA
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44
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Aguilera A, Gómez-González B. DNA-RNA hybrids: the risks of DNA breakage during transcription. Nat Struct Mol Biol 2017; 24:439-443. [PMID: 28471430 DOI: 10.1038/nsmb.3395] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/05/2017] [Indexed: 12/28/2022]
Abstract
Although R loops can occur at different genomic locations, the factors that determine their formation and frequency remain unclear. Emerging evidence indicates that DNA breaks stimulate DNA-RNA hybrid formation. Here, we discuss the possibility that formation of hybrids may be an inevitable risk of DNA breaks that occur within actively transcribed regions. While such hybrids must be removed to permit repair, their potential role as repair intermediates remains to be established.
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Affiliation(s)
- Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
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45
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Abstract
Transcription-coupled DNA repair (TCR) acts on lesions in the transcribed strand of active genes. Helix distorting adducts and other forms of DNA damage often interfere with the progression of the transcription apparatus. Prolonged stalling of RNA polymerase can promote genome instability and also induce cell cycle arrest and apoptosis. These generally unfavorable events are counteracted by RNA polymerase-mediated recruitment of specific proteins to the sites of DNA damage to perform TCR and eventually restore transcription. In this perspective we discuss the decision-making process to employ TCR and we elucidate the intricate biochemical pathways leading to TCR in E. coli and human cells.
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Affiliation(s)
- Bibhusita Pani
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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46
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Abstract
Transcription is tightly regulated in response to DNA damage. Rapid and transient pausing of RNA polymerase II (RNAPII ) is indeed critical to restrict the production of aberrant transcripts from damaged loci and to prevent deleterious collisions between transcription and repair machineries. Yet, how DNA lesions signal to the transcription machinery to coordinate DNA repair with transcriptional silencing is not fully elucidated. In this issue of EMBO Reports , Awwad et al 1 bring a new piece to the puzzle by identifying the negative transcription elongation factor NELF as a critical player in this process. They demonstrate that NELF is recruited to DNA double‐strand breaks (DSB s) near transcriptionally active genes in a poly(ADP ‐ribose)‐ and RNAPII ‐dependent manner to promote transcriptional repression and facilitate DSB repair.
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Affiliation(s)
- Sophie E Polo
- Epigenetics & Cell Fate CentreUMR7216 CNRSSorbonne Paris CitéParis Diderot UniversityParisFrance
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Marnef A, Cohen S, Legube G. Transcription-Coupled DNA Double-Strand Break Repair: Active Genes Need Special Care. J Mol Biol 2017; 429:1277-1288. [PMID: 28363678 DOI: 10.1016/j.jmb.2017.03.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/22/2022]
Abstract
For decades, it has been speculated that specific loci on eukaryotic chromosomes are inherently susceptible to breakage. The advent of high-throughput genomic technologies has now paved the way to their identification. A wealth of data suggests that transcriptionally active loci are particularly fragile and that a specific DNA damage response is activated and dedicated to their repair. Here, we review current understanding of the crosstalk between transcription and double-strand break repair, from the reasons underlying the intrinsic fragility of genes to the mechanisms that restore the integrity of damaged transcription units.
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Affiliation(s)
- Aline Marnef
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, 118 Route de Narbonne, 31062 Toulouse, France
| | - Sarah Cohen
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, 118 Route de Narbonne, 31062 Toulouse, France
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, 118 Route de Narbonne, 31062 Toulouse, France.
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