1
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Zhang Z, Xu J, Liu J, Wang J, Lei L. SEC: A core hub during cell fate alteration. FASEB J 2024; 38:e23680. [PMID: 38758186 DOI: 10.1096/fj.202400514r] [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: 03/06/2024] [Revised: 04/18/2024] [Accepted: 05/07/2024] [Indexed: 05/18/2024]
Abstract
Pol II pause release is a rate-limiting step in gene transcription, influencing various cell fate alterations. Numerous proteins orchestrate Pol II pause release, thereby playing pivotal roles in the intricate process of cellular fate modulation. Super elongation complex (SEC), a large assembly comprising diverse protein components, has garnered attention due to its emerging significance in orchestrating physiological and pathological cellular identity changes by regulating the transcription of crucial genes. Consequently, SEC emerges as a noteworthy functional complex capable of modulating cell fate alterations. Therefore, a comprehensive review is warranted to systematically summarize the core roles of SEC in different types of cell fate alterations. This review focuses on elucidating the current understanding of the structural and functional basis of SEC. Additionally, we discuss the intricate regulatory mechanisms governing SEC in various models of cell fate alteration, encompassing both physiological and pathological contexts. Furthermore, leveraging the existing knowledge of SEC, we propose some insightful directions for future research, aiming to enhance our mechanistic and functional comprehension of SEC within the diverse landscape of cell fate alterations.
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Affiliation(s)
- Zhijing Zhang
- College of Life Science, Northeast Agricultural University, Harbin, Heilongjiang Province, China
- Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Jingyi Xu
- Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Jiqiang Liu
- Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Jiaqiang Wang
- College of Life Science, Northeast Agricultural University, Harbin, Heilongjiang Province, China
| | - Lei Lei
- Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang Province, China
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2
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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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3
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Talukdar P, Pal S, Biswas D. Post-translational modification-dependent oligomerization switch in regulation of global transcription and DNA damage repair during genotoxic stress. Nat Commun 2024; 15:4128. [PMID: 38750015 PMCID: PMC11096357 DOI: 10.1038/s41467-024-48530-8] [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: 09/18/2023] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Mechanisms of functional cross-talk between global transcriptional repression and efficient DNA damage repair during genotoxic stress are poorly known. In this study, using human AF9 as representative of Super Elongation Complex (SEC) components, we delineate detailed mechanisms of these processes. Mechanistically, we describe that Poly-Serine domain-mediated oligomerization is pre-requisite for AF9 YEATS domain-mediated TFIID interaction-dependent SEC recruitment at the promoter-proximal region for release of paused RNA polymerase II. Interestingly, during genotoxic stress, CaMKII-mediated phosphorylation-dependent nuclear export of AF9-specific deacetylase HDAC5 enhances concomitant PCAF-mediated acetylation of K339 residue. This causes monomerization of AF9 and reduces TFIID interaction for transcriptional downregulation. Furthermore, the K339 acetylation-dependent enhanced AF9-DNA-PKc interaction leads to phosphorylation at S395 residue which reduces AF9-SEC interaction resulting in transcriptional downregulation and efficient repair of DNA damage. After repair, nuclear re-entry of HDAC5 reduces AF9 acetylation and restores its TFIID and SEC interaction to restart transcription.
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Affiliation(s)
| | - Sujay Pal
- CSIR-Indian Institute of Chemical Biology, Kolkata, 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- CSIR-Indian Institute of Chemical Biology, Kolkata, 700032, India.
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4
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Jayakumar S, Patel M, Boulet F, Aziz H, Brooke GN, Tummala H, Pradeepa MM. PSIP1/LEDGF reduces R-loops at transcription sites to maintain genome integrity. Nat Commun 2024; 15:361. [PMID: 38191578 PMCID: PMC10774266 DOI: 10.1038/s41467-023-44544-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 12/18/2023] [Indexed: 01/10/2024] Open
Abstract
R-loops that accumulate at transcription sites pose a persistent threat to genome integrity. PSIP1 is a chromatin protein associated with transcriptional elongation complex, possesses histone chaperone activity, and is implicated in recruiting RNA processing and DNA repair factors to transcription sites. Here, we show that PSIP1 interacts with R-loops and other proteins involved in R-loop homeostasis, including PARP1. Genome-wide mapping of PSIP1, R-loops and γ-H2AX in PSIP1-depleted human and mouse cell lines revealed an accumulation of R-loops and DNA damage at gene promoters in the absence of PSIP1. R-loop accumulation causes local transcriptional arrest and transcription-replication conflict, leading to DNA damage. PSIP1 depletion increases 53BP1 foci and reduces RAD51 foci, suggesting altered DNA repair choice. Furthermore, PSIP1 depletion increases the sensitivity of cancer cells to PARP1 inhibitors and DNA-damaging agents that induce R-loop-induced DNA damage. These findings provide insights into the mechanism through which PSIP1 maintains genome integrity at the site of transcription.
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Affiliation(s)
- Sundarraj Jayakumar
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
- Bhabha Atomic Research Centre, Mumbai, India
| | - Manthan Patel
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Fanny Boulet
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Hadicha Aziz
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Greg N Brooke
- School of Life Sciences, University of Essex, Colchester, UK
| | - Hemanth Tummala
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Madapura M Pradeepa
- Blizard Institute; Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
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5
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Pal S, Yadav D, Biswas D. ATM-mediated ELL phosphorylation enhances its self-association through increased EAF1 interaction and inhibits global transcription during genotoxic stress. Nucleic Acids Res 2022; 50:10995-11012. [PMID: 36305813 PMCID: PMC9638944 DOI: 10.1093/nar/gkac943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/16/2022] [Accepted: 10/15/2022] [Indexed: 12/05/2022] Open
Abstract
Mammalian cells immediately inhibit transcription upon exposure to genotoxic stress to avoid fatal collision between ongoing transcription and newly recruited DNA repair machineries to protect genomic integrity. However, mechanisms of this early transcriptional inhibition are poorly understood. In this study, we decipher a novel role of human EAF1, a positive regulator of ELL-dependent RNA Polymerase II-mediated transcription in vitro, in regulation of temporal inhibition of transcription during genotoxic stress. Our results show that, besides Super Elongation Complex (SEC) and Little Elongation Complex (LEC), human ELL (aka ELL1) also forms a complex with EAF1 alone. Interestingly, contrary to the in vitro studies, EAF1 inhibits ELL-dependent RNA polymerase II-mediated transcription of diverse target genes. Mechanistically, we show that intrinsic self-association property of ELL leads to its reduced interaction with other SEC components. EAF1 enhances ELL self-association and thus reduces its interaction with other SEC components leading to transcriptional inhibition. Physiologically, we show that upon exposure to genotoxic stress, ATM-mediated ELL phosphorylation-dependent enhanced EAF1 association results in reduced ELL interaction with other SEC components that lead to global transcriptional inhibition. Thus, we describe an important mechanism of dynamic transcriptional regulation during genotoxic stress involving post-translational modification of a key elongation factor.
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Affiliation(s)
- Sujay Pal
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology , 4, Raja S. C. Mullick Road , Kolkata - 32, India
- Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002, India
| | - Dipika Yadav
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology , 4, Raja S. C. Mullick Road , Kolkata - 32, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology , 4, Raja S. C. Mullick Road , Kolkata - 32, India
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6
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The Paf1 complex is required for RNA polymerase II removal in response to DNA damage. Proc Natl Acad Sci U S A 2022; 119:e2207332119. [PMID: 36161924 DOI: 10.1073/pnas.2207332119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rpb1, the largest subunit of RNA polymerase II (RNAPII), is rapidly polyubiquitinated and degraded in response to DNA damage; this process is considered to be a "mechanism of last resort'' employed by cells. The underlying mechanism of this process remains elusive. Here, we uncovered a previously uncharacterized multistep pathway in which the polymerase-associated factor 1 (Paf1) complex (PAF1C, composed of the subunits Ctr9, Paf1, Leo1, Cdc73, and Rtf1) is involved in regulating the RNAPII pool by stimulating Elongin-Cullin E3 ligase complex-mediated Rpb1 polyubiquitination and subsequent degradation by the proteasome following DNA damage. Mechanistically, Spt5 is dephosphorylated following DNA damage, thereby weakening the interaction between the Rtf1 subunit and Spt5, which might be a key step in initiating Rpb1 degradation. Next, Rad26 is loaded onto stalled RNAPII to replace the Spt4/Spt5 complex in an RNAPII-dependent manner and, in turn, recruits more PAF1C to DNA lesions via the binding of Rad26 to the Leo1 subunit. Importantly, the PAF1C, assembled in a Ctr9-mediated manner, coordinates with Rad26 to localize the Elongin-Cullin complex on stalled RNAPII, thereby inducing RNAPII removal, in which the heterodimer Paf1/Leo1 and the subunit Cdc73 play important roles. Together, our results clearly revealed a new role of the intact PAF1C in regulating the RNAPII pool in response to DNA damage.
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7
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St Germain C, Zhao H, Barlow JH. Transcription-Replication Collisions-A Series of Unfortunate Events. Biomolecules 2021; 11:1249. [PMID: 34439915 PMCID: PMC8391903 DOI: 10.3390/biom11081249] [Citation(s) in RCA: 10] [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] [Received: 07/21/2021] [Revised: 08/12/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
Transcription-replication interactions occur when DNA replication encounters genomic regions undergoing transcription. Both replication and transcription are essential for life and use the same DNA template making conflicts unavoidable. R-loops, DNA supercoiling, DNA secondary structure, and chromatin-binding proteins are all potential obstacles for processive replication or transcription and pose an even more potent threat to genome integrity when these processes co-occur. It is critical to maintaining high fidelity and processivity of transcription and replication while navigating through a complex chromatin environment, highlighting the importance of defining cellular pathways regulating transcription-replication interaction formation, evasion, and resolution. Here we discuss how transcription influences replication fork stability, and the safeguards that have evolved to navigate transcription-replication interactions and maintain genome integrity in mammalian cells.
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Affiliation(s)
- Commodore St Germain
- School of Mathematics and Science, Solano Community College, 4000 Suisun Valley Road, Fairfield, CA 94534, USA
- Department of Microbiology and Molecular Genetics, University of California Davis, One Shields Avenue, Davis, CA 95616, USA;
| | - Hongchang Zhao
- Department of Microbiology and Molecular Genetics, University of California Davis, One Shields Avenue, Davis, CA 95616, USA;
| | - Jacqueline H. Barlow
- Department of Microbiology and Molecular Genetics, University of California Davis, One Shields Avenue, Davis, CA 95616, USA;
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8
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Lebraud E, Pinna G, Siberchicot C, Depagne J, Busso D, Fantini D, Irbah L, Robeska E, Kratassiouk G, Ravanat JL, Epe B, Radicella JP, Campalans A. Chromatin recruitment of OGG1 requires cohesin and mediator and is essential for efficient 8-oxoG removal. Nucleic Acids Res 2020; 48:9082-9097. [PMID: 32710616 PMCID: PMC7498353 DOI: 10.1093/nar/gkaa611] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/07/2020] [Accepted: 07/15/2020] [Indexed: 12/29/2022] Open
Abstract
One of the most abundant DNA lesions induced by oxidative stress is the highly mutagenic 8-oxoguanine (8-oxoG), which is specifically recognized by 8-oxoguanine DNA glycosylase 1 (OGG1) to initiate its repair. How DNA glycosylases find small non-helix-distorting DNA lesions amongst millions of bases packaged in the chromatin-based architecture of the genome remains an open question. Here, we used a high-throughput siRNA screening to identify factors involved in the recognition of 8-oxoG by OGG1. We show that cohesin and mediator subunits are required for re-localization of OGG1 and other base excision repair factors to chromatin upon oxidative stress. The association of OGG1 with euchromatin is necessary for the removal of 8-oxoG. Mediator subunits CDK8 and MED12 bind to chromatin and interact with OGG1 in response to oxidative stress, suggesting they participate in the recruitment of the DNA glycosylase. The oxidative stress-induced association between the cohesin and mediator complexes and OGG1 reveals an unsuspected function of those complexes in the maintenance of genomic stability.
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Affiliation(s)
- Emilie Lebraud
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Guillaume Pinna
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91198 Gif-sur-Yvette, France
| | - Capucine Siberchicot
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Jordane Depagne
- Institute of Cellular and Molecular Radiobiology, U1274 INSERM, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Didier Busso
- Institute of Cellular and Molecular Radiobiology, U1274 INSERM, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Damiano Fantini
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Lamya Irbah
- Institute of Cellular and Molecular Radiobiology, U1274 INSERM, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Elena Robeska
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Gueorgui Kratassiouk
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91198 Gif-sur-Yvette, France
| | - Jean-Luc Ravanat
- Univ. Grenoble Alpes, CEA, CNRS IRIG/SyMMES, F-38054 Grenoble, France
| | - Bernd Epe
- Institute of Pharmaceutical and Biomedical Sciences, University of Mainz, Germany
| | - J Pablo Radicella
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
| | - Anna Campalans
- Institut de Biologie François Jacob, Institute of Cellular and Molecular Radiobiology, Université Paris-Saclay, Université de Paris, CEA, 18 route du Panorama, F-92265 Fontenay-aux-Roses, France
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9
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Carlaw TM, Zhang LH, Ross CJD. CRISPR/Cas9 Editing: Sparking Discussion on Safety in Light of the Need for New Therapeutics. Hum Gene Ther 2020; 31:794-807. [PMID: 32586150 DOI: 10.1089/hum.2020.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent advances in genome sequencing have greatly improved our ability to understand and identify the causes of genetic diseases. However, there remains an urgent need for innovative, safe, and effective treatments for these diseases. CRISPR-based genome editing systems have become important and powerful tools in the laboratory, and efforts are underway to translate these into patient therapies. Therapeutic base editing is one form of genome engineering that has gained much interest because of its simplicity, specificity, and effectiveness. Base editors are a fusion of a partially deactivated Cas9 enzyme with nickase function, together with a base-modifying enzyme. They are capable of precisely targeting and repairing a pathogenic mutation to restore the normal function of a gene, ideally without disturbing the rest of the genome. In the past year, research has identified new safety concerns of base editors and sparked new innovations to improve their safety. In this review, we provide an overview of the recent advances in the safety and effectiveness of therapeutic base editors and prime editing.
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Affiliation(s)
| | - Lin-Hua Zhang
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
| | - Colin J D Ross
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
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10
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Botto AEC, Muñoz JC, Giono LE, Nieto-Moreno N, Cuenca C, Kornblihtt AR, Muñoz MJ. Reciprocal regulation between alternative splicing and the DNA damage response. Genet Mol Biol 2020; 43:e20190111. [PMID: 32236390 PMCID: PMC7197977 DOI: 10.1590/1678-4685-gmb-2019-0111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 12/16/2019] [Indexed: 12/16/2022] Open
Abstract
Splicing, the process that catalyzes intron removal and flanking exon ligation, can occur in different ways (alternative splicing) in immature RNAs transcribed from a single gene. In order to adapt to a particular context, cells modulate not only the quantity but also the quality (alternative isoforms) of their transcriptome. Since 95% of the human coding genome is subjected to alternative splicing regulation, it is expected that many cellular pathways are modulated by alternative splicing, as is the case for the DNA damage response. Moreover, recent evidence demonstrates that upon a genotoxic insult, classical DNA damage response kinases such as ATM, ATR and DNA-PK orchestrate the gene expression response therefore modulating alternative splicing which, in a reciprocal way, shapes the response to a damaging agent.
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Affiliation(s)
- Adrian E Cambindo Botto
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Juan C Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Luciana E Giono
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Nicolás Nieto-Moreno
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Carmen Cuenca
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Alberto R Kornblihtt
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Manuel J Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina.,Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Milan, Italy.,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
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11
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Singh A, Choudhuri P, Chandradoss KR, Lal M, Mishra SK, Sandhu KS. Does genome surveillance explain the global discrepancy between binding and effect of chromatin factors? FEBS Lett 2020; 594:1339-1353. [PMID: 31930486 DOI: 10.1002/1873-3468.13729] [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: 09/17/2019] [Revised: 12/16/2019] [Accepted: 12/19/2019] [Indexed: 11/11/2022]
Abstract
Knocking out a chromatin factor often does not alter the transcription of its binding targets. What explains the observed disconnect between binding and effect? We hypothesize that this discrepancy could be associated with the role of chromatin factors in maintaining genetic and epigenetic integrity at promoters, and not necessarily with transcription. Through re-analysis of published datasets, we present several lines of evidence that support our hypothesis and deflate the popular assumptions. We also tested the hypothesis through mutation accumulation assays on yeast knockouts of chromatin factors. Altogether, the proposed hypothesis presents a simple explanation for the global discord between chromatin factor binding and effect. Future work in this direction might fortify the hypothesis and elucidate the underlying mechanisms.
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Affiliation(s)
- Arashdeep Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Poulami Choudhuri
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | | | - Mohan Lal
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
| | - Kuljeet Singh Sandhu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER)-Mohali, India
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12
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Chiang HC, Zhang X, Li J, Zhao X, Chen J, Wang HTH, Jatoi I, Brenner A, Hu Y, Li R. BRCA1-associated R-loop affects transcription and differentiation in breast luminal epithelial cells. Nucleic Acids Res 2019; 47:5086-5099. [PMID: 30982901 PMCID: PMC6547407 DOI: 10.1093/nar/gkz262] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 03/06/2019] [Accepted: 04/01/2019] [Indexed: 12/17/2022] Open
Abstract
BRCA1-associated basal-like breast cancer originates from luminal progenitor cells. Breast epithelial cells from cancer-free BRCA1 mutation carriers are defective in luminal differentiation. However, how BRCA1 deficiency leads to lineage-specific differentiation defect is not clear. BRCA1 is implicated in resolving R-loops, DNA-RNA hybrid structures associated with genome instability and transcriptional regulation. We recently showed that R-loops are preferentially accumulated in breast luminal epithelial cells of BRCA1 mutation carriers. Here, we interrogate the impact of a BRCA1 mutation-associated R-loop located in a putative transcriptional enhancer upstream of the ERα-encoding ESR1 gene. Genetic ablation confirms the relevance of this R-loop-containing region to enhancer-promoter interactions and transcriptional activation of the corresponding neighboring genes, including ESR1, CCDC170 and RMND1. BRCA1 knockdown in ERα+ luminal breast cancer cells increases intensity of this R-loop and reduces transcription of its neighboring genes. The deleterious effect of BRCA1 depletion on transcription is mitigated by ectopic expression of R-loop-removing RNase H1. Furthermore, RNase H1 overexpression in primary breast cells from BRCA1 mutation carriers results in a shift from luminal progenitor cells to mature luminal cells. Our findings suggest that BRCA1-dependent R-loop mitigation contributes to luminal cell-specific transcription and differentiation, which could in turn suppress BRCA1-associated tumorigenesis.
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Affiliation(s)
- Huai-Chin Chiang
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Xiaowen Zhang
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Jingwei Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xiayan Zhao
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jerry Chen
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Howard T-H Wang
- Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ismail Jatoi
- Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew Brenner
- Department of Medicine, The Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Yanfen Hu
- Department of Anatomy & Cell Biology, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Rong Li
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
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13
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AFF1 acetylation by p300 temporally inhibits transcription during genotoxic stress response. Proc Natl Acad Sci U S A 2019; 116:22140-22151. [PMID: 31611376 PMCID: PMC6823056 DOI: 10.1073/pnas.1907097116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mammalian cells are constantly exposed to genotoxic agents that can lead to DNA damage, genomic instability, and diseases, including cancers. Maintenance of genomic stability, a prerequisite for survival and proper functions of cells, is facilitated by the cellular DNA repair machinery. One of the earliest responses to DNA damage is a transient inhibition of transcription to avoid fatal collisions between the DNA repair and transcriptional machineries. However, the mechanisms underlying this early transcriptional inhibition are poorly understood. Our study establishes a critical role for AFF1, a key component of super elongation complex, in early transcription inhibition and cell survival upon DNA damage, as well as a mechanism involving p300-mediated acetylation of AFF1 and consequent inactivation of the super elongation complex. Soon after exposure to genotoxic reagents, mammalian cells inhibit transcription to prevent collisions with repair machinery and to mount a proper DNA damage response. However, mechanisms underlying early transcriptional inhibition are poorly understood. In this report, we show that site-specific acetylation of super elongation complex (SEC) subunit AFF1 by p300 reduces its interaction with other SEC components and impairs P-TEFb−mediated C-terminal domain phosphorylation of RNA polymerase II both in vitro and in vivo. Reexpression of wild-type AFF1, but not an acetylation mimic mutant, restores SEC component recruitment and target gene expression in AFF1 knockdown cells. Physiologically, we show that, upon genotoxic exposure, p300-mediated AFF1 acetylation is dynamic and strongly correlated with concomitant global down-regulation of transcription—and that this can be reversed by overexpression of an acetylation-defective AFF1 mutant. Therefore, we describe a mechanism of dynamic transcriptional regulation involving p300-mediated acetylation of a key elongation factor during genotoxic stress.
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14
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Barman P, Reddy D, Bhaumik SR. Mechanisms of Antisense Transcription Initiation with Implications in Gene Expression, Genomic Integrity and Disease Pathogenesis. Noncoding RNA 2019; 5:ncrna5010011. [PMID: 30669611 PMCID: PMC6468509 DOI: 10.3390/ncrna5010011] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/01/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Non-coding antisense transcripts arise from the strand opposite the sense strand. Over 70% of the human genome generates non-coding antisense transcripts while less than 2% of the genome codes for proteins. Antisense transcripts and/or the act of antisense transcription regulate gene expression and genome integrity by interfering with sense transcription and modulating histone modifications or DNA methylation. Hence, they have significant pathological and physiological relevance. Indeed, antisense transcripts were found to be associated with various diseases including cancer, diabetes, cardiac and neurodegenerative disorders, and, thus, have promising potentials for prognostic and diagnostic markers and therapeutic development. However, it is not clearly understood how antisense transcription is initiated and epigenetically regulated. Such knowledge would provide new insights into the regulation of antisense transcription, and hence disease pathogenesis with therapeutic development. The recent studies on antisense transcription initiation and its epigenetic regulation, which are limited, are discussed here. Furthermore, we concisely describe how antisense transcription/transcripts regulate gene expression and genome integrity with implications in disease pathogenesis and therapeutic development.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
| | - Divya Reddy
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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15
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Abstract
Maintenance of genomic integrity depends on the spatiotemporal recruitment and regulation of DNA damage response and repair proteins at DNA damage sites. These highly dynamic processes have been widely studied using laser microirradiation coupled with fluorescence microscopy. Laser microirradiation has provided a powerful methodology to identify and determine mechanisms of DNA damage response pathways. Here we describe methods used to analyze protein recruitment dynamics of fluorescently tagged or endogenous proteins to laser-induced DNA damage sites using laser scanning and fluorescence microscopy. We further describe multiple applications employing these techniques to study additional processes at DNA damage sites including transcription. Together, we aim to provide robust visualization methods employing laser-microirradiation to detect and determine protein behavior, functions and dynamics in response to DNA damage in mammalian cells.
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16
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Poetsch AR, Boulton SJ, Luscombe NM. Genomic landscape of oxidative DNA damage and repair reveals regioselective protection from mutagenesis. Genome Biol 2018; 19:215. [PMID: 30526646 PMCID: PMC6284305 DOI: 10.1186/s13059-018-1582-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 11/08/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND DNA is subject to constant chemical modification and damage, which eventually results in variable mutation rates throughout the genome. Although detailed molecular mechanisms of DNA damage and repair are well understood, damage impact and execution of repair across a genome remain poorly defined. RESULTS To bridge the gap between our understanding of DNA repair and mutation distributions, we developed a novel method, AP-seq, capable of mapping apurinic sites and 8-oxo-7,8-dihydroguanine bases at approximately 250-bp resolution on a genome-wide scale. We directly demonstrate that the accumulation rate of apurinic sites varies widely across the genome, with hot spots acquiring many times more damage than cold spots. Unlike single nucleotide variants (SNVs) in cancers, damage burden correlates with marks for open chromatin notably H3K9ac and H3K4me2. Apurinic sites and oxidative damage are also highly enriched in transposable elements and other repetitive sequences. In contrast, we observe a reduction at chromatin loop anchors with increased damage load towards inactive compartments. Less damage is found at promoters, exons, and termination sites, but not introns, in a seemingly transcription-independent but GC content-dependent manner. Leveraging cancer genomic data, we also find locally reduced SNV rates in promoters, coding sequence, and other functional elements. CONCLUSIONS Our study reveals that oxidative DNA damage accumulation and repair differ strongly across the genome, but culminate in a previously unappreciated mechanism that safeguards the regulatory and coding regions of genes from mutations.
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Affiliation(s)
- Anna R Poetsch
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan.
- UCL Genetics Institute, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Nicholas M Luscombe
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
- UCL Genetics Institute, University College London, Gower Street, London, WC1E 6BT, UK
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17
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Structural basis of DNA lesion recognition for eukaryotic transcription-coupled nucleotide excision repair. DNA Repair (Amst) 2018; 71:43-55. [PMID: 30174298 DOI: 10.1016/j.dnarep.2018.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Eukaryotic transcription-coupled nucleotide excision repair (TC-NER) is a pathway that removes DNA lesions capable of blocking RNA polymerase II (Pol II) transcription from the template strand. This process is initiated by lesion-arrested Pol II and the recruitment of Cockayne Syndrome B protein (CSB). In this review, we will focus on the lesion recognition steps of eukaryotic TC-NER and summarize the recent research progress toward understanding the structural basis of Pol II-mediated lesion recognition and Pol II-CSB interactions. We will discuss the roles of CSB in both TC-NER initiation and transcription elongation. Finally, we propose an updated model of tripartite lesion recognition and verification for TC-NER in which CSB ensures Pol II-mediated recognition of DNA lesions for TC-NER.
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18
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Global unleashing of transcription elongation waves in response to genotoxic stress restricts somatic mutation rate. Nat Commun 2017; 8:2076. [PMID: 29233992 PMCID: PMC5727188 DOI: 10.1038/s41467-017-02145-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 11/08/2017] [Indexed: 01/11/2023] Open
Abstract
Complex molecular responses preserve gene expression accuracy and genome integrity in the face of environmental perturbations. Here we report that, in response to UV irradiation, RNA polymerase II (RNAPII) molecules are dynamically and synchronously released from promoter-proximal regions into elongation to promote uniform and accelerated surveillance of the whole transcribed genome. The maximised influx of de novo released RNAPII correlates with increased damage-sensing, as confirmed by RNAPII progressive accumulation at dipyrimidine sites and by the average slow-down of elongation rates in gene bodies. In turn, this transcription elongation ‘safe’ mode guarantees efficient DNA repair regardless of damage location, gene size and transcription level. Accordingly, we detect low and homogenous rates of mutational signatures associated with UV exposure or cigarette smoke across all active genes. Our study reveals a novel advantage for transcription regulation at the promoter-proximal level and provides unanticipated insights into how active transcription shapes the mutagenic landscape of cancer genomes. Precise orchestration of gene expression regulation upon DNA damage is essential for genome integrity. Here the authors identify a novel widespread stress-triggered defence mechanism that promotes rapid transcription-driven genomic surveillance thus limiting mutagenesis and shaping cancer genomes.
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19
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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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20
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Awwad SW, Abu-Zhayia ER, Guttmann-Raviv N, Ayoub N. NELF-E is recruited to DNA double-strand break sites to promote transcriptional repression and repair. EMBO Rep 2017; 18:745-764. [PMID: 28336775 PMCID: PMC5412775 DOI: 10.15252/embr.201643191] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 01/12/2023] Open
Abstract
Double-strand breaks (DSBs) trigger rapid and transient transcription pause to prevent collisions between repair and transcription machineries at damage sites. Little is known about the mechanisms that ensure transcriptional block after DNA damage. Here, we reveal a novel role of the negative elongation factor NELF in blocking transcription activity nearby DSBs. We show that NELF-E and NELF-A are rapidly recruited to DSB sites. Furthermore, NELF-E recruitment and its repressive activity are both required for switching off transcription at DSBs. Remarkably, using I-SceI endonuclease and CRISPR-Cas9 systems, we observe that NELF-E is preferentially recruited, in a PARP1-dependent manner, to DSBs induced upstream of transcriptionally active rather than inactive genes. Moreover, the presence of RNA polymerase II is a prerequisite for the preferential recruitment of NELF-E to DNA break sites. Additionally, we demonstrate that NELF-E is required for intact repair of DSBs. Altogether, our data identify the NELF complex as a new component in the DNA damage response.
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Affiliation(s)
- Samah W Awwad
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Enas R Abu-Zhayia
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Noga Guttmann-Raviv
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Nabieh Ayoub
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
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21
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Basu M, Khan MW, Chakrabarti P, Das C. Chromatin reader ZMYND8 is a key target of all trans retinoic acid-mediated inhibition of cancer cell proliferation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:450-459. [DOI: 10.1016/j.bbagrm.2017.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/16/2017] [Accepted: 02/11/2017] [Indexed: 01/10/2023]
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22
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Xiang Y, Laurent B, Hsu CH, Nachtergaele S, Lu Z, Sheng W, Xu C, Chen H, Ouyang J, Wang S, Ling D, Hsu PH, Zou L, Jambhekar A, He C, Shi Y. RNA m 6A methylation regulates the ultraviolet-induced DNA damage response. Nature 2017; 543:573-576. [PMID: 28297716 PMCID: PMC5490984 DOI: 10.1038/nature21671] [Citation(s) in RCA: 628] [Impact Index Per Article: 89.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/27/2017] [Indexed: 12/17/2022]
Abstract
Cell proliferation and survival require the faithful maintenance and propagation of genetic information, which are threatened by the ubiquitous sources of DNA damage present intracellularly and in the external environment. A system of DNA repair, called the DNA damage response, detects and repairs damaged DNA and prevents cell division until the repair is complete. Here we report that methylation at the 6 position of adenosine (m6A) in RNA is rapidly (within 2 min) and transiently induced at DNA damage sites in response to ultraviolet irradiation. This modification occurs on numerous poly(A)+ transcripts and is regulated by the methyltransferase METTL3 (methyltransferase-like 3) and the demethylase FTO (fat mass and obesity-associated protein). In the absence of METTL3 catalytic activity, cells showed delayed repair of ultraviolet-induced cyclobutane pyrimidine adducts and elevated sensitivity to ultraviolet, demonstrating the importance of m6A in the ultraviolet-responsive DNA damage response. Multiple DNA polymerases are involved in the ultraviolet response, some of which resynthesize DNA after the lesion has been excised by the nucleotide excision repair pathway, while others participate in trans-lesion synthesis to allow replication past damaged lesions in S phase. DNA polymerase κ (Pol κ), which has been implicated in both nucleotide excision repair and trans-lesion synthesis, required the catalytic activity of METTL3 for immediate localization to ultraviolet-induced DNA damage sites. Importantly, Pol κ overexpression qualitatively suppressed the cyclobutane pyrimidine removal defect associated with METTL3 loss. Thus, we have uncovered a novel function for RNA m6A modification in the ultraviolet-induced DNA damage response, and our findings collectively support a model in which m6A RNA serves as a beacon for the selective, rapid recruitment of Pol κ to damage sites to facilitate repair and cell survival.
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Affiliation(s)
- Yang Xiang
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Benoit Laurent
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Chih-Hung Hsu
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sigrid Nachtergaele
- Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Institute for Biophysical Dynamics, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Howard Hughes Medical Institute, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Zhike Lu
- Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Institute for Biophysical Dynamics, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Howard Hughes Medical Institute, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Wanqiang Sheng
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Chuanyun Xu
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Hao Chen
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02109, USA.,Department of Pathology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02109, USA
| | - Siqing Wang
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dominic Ling
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Pang-Hung Hsu
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung City 202, Taiwan
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02109, USA.,Department of Pathology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02109, USA
| | - Ashwini Jambhekar
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Chuan He
- Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Institute for Biophysical Dynamics, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.,Howard Hughes Medical Institute, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Yang Shi
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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23
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Shin JH, Xu L, Wang D. Mechanism of transcription-coupled DNA modification recognition. Cell Biosci 2017; 7:9. [PMID: 28239446 PMCID: PMC5320713 DOI: 10.1186/s13578-016-0133-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/02/2016] [Indexed: 11/10/2022] Open
Abstract
As a key enzyme for gene expression, RNA polymerase II (pol II) reads along the DNA template and catalyzes accurate mRNA synthesis during transcription. On the other hand, genomic DNA is under constant attack by endogenous and environmental stresses. These attack cause many DNA lesions. Pol II functions as a specific sensor that is able to recognize changes in DNA sequences and structures and induces different outcomes. A critical question in the field is how Pol II recognizes and senses these DNA modifications or lesions. Recent studies provided new insights into understanding this critical question. In this mini-review, we would like to focus on three classes of DNA lesions/modifications: (1) Bulky, DNA-distorting lesions that block pol II transcription, (2) small DNA lesions that promote pol II pausing and error-prone transcriptional bypass, and (3) endogenous enzyme-catalyzed DNA modifications that lead to pol II pausing and error-free transcriptional bypass.
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Affiliation(s)
- Ji Hyun Shin
- Department of Cellular and Molecular Medicine, School of Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Liang Xu
- Department of Cellular and Molecular Medicine, School of Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Dong Wang
- Department of Cellular and Molecular Medicine, School of Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
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24
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Kee Y. Putting the brakes on transcription at damaged chromatin: Do Polycomb silencers do more than modify histones? Mol Cell Oncol 2017; 3:e1244513. [PMID: 28090582 DOI: 10.1080/23723556.2016.1244513] [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: 09/28/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 10/20/2022]
Abstract
One of the cellular responses to DNA damage is to monitor and execute temporary arrest of RNA synthesis at chromatin lesions. The Polycomb silencer BMI1 is a well-known contributor to this process. We recently described a new mode of BMI1-mediated transcription arrest at lesions that involves UBR5 E3 ligase and FACT histone chaperon.
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Affiliation(s)
- Younghoon Kee
- Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida , Tampa, FL, USA
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25
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BMI1-UBR5 axis regulates transcriptional repression at damaged chromatin. Proc Natl Acad Sci U S A 2016; 113:11243-11248. [PMID: 27647897 DOI: 10.1073/pnas.1610735113] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BMI1 is a component of the Polycomb Repressive Complex 1 (PRC1), which plays a key role in maintaining epigenetic silencing during development. BMI1 also participates in gene silencing during DNA damage response, but the precise downstream function of BMI1 in gene silencing is unclear. Here we identified the UBR5 E3 ligase as a downstream factor of BMI1. We found that UBR5 forms damage-inducible nuclear foci in a manner dependent on the PRC1 components BMI1, RNF1 (RING1a), and RNF2 (RING1b). Whereas transcription is repressed at UV-induced lesions on chromatin, depletion of the PRC1 members or UBR5 alone derepressed transcription elongation at these sites, suggesting that UBR5 functions in a linear pathway with PRC1 in inducing gene silencing at lesions. Mass spectrometry (MS) analysis revealed that UBR5 associates with BMI1 as well as FACT components SPT16 and SSRP1. We found that UBR5 localizes to the UV-induced lesions along with SPT16. We show that UBR5 ubiquitinates SPT16, and depletion of UBR5 or BMI1 leads to an enlargement of SPT16 foci size at UV lesions, suggesting that UBR5 and BMI1 repress SPT16 enrichment at the damaged sites. Consistently, depletion of the FACT components effectively reversed the transcriptional derepression incurred in the UBR5 and BMI1 KO cells. Finally, UBR5 and BMI1 KO cells are hypersensitive to UV, which supports the notion that faulty RNA synthesis at damaged sites is harmful to the cell fitness. Altogether, these results suggest that BMI1 and UBR5 repress the polymerase II (Pol II)-mediated transcription at damaged sites, by negatively regulating the FACT-dependent Pol II elongation.
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26
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Abstract
Terminating transcription is a highly intricate process for mammalian protein-coding genes. First, the chromatin template slows down transcription at the gene end. Then, the transcript is cleaved at the poly(A) signal to release the messenger RNA. The remaining transcript is selectively unraveled and degraded. This induces critical conformational changes in the heart of the enzyme that trigger termination. Termination can also occur at variable positions along the gene and so prevent aberrant transcript formation or intentionally make different transcripts. These may form multiple messenger RNAs with altered regulatory properties or encode different proteins. Finally, termination can be perturbed to achieve particular cellular needs or blocked in cancer or virally infected cells. In such cases, failure to terminate transcription can spell disaster for the cell.
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Affiliation(s)
- Nick J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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27
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Kantidakis T, Saponaro M, Mitter R, Horswell S, Kranz A, Boeing S, Aygün O, Kelly GP, Matthews N, Stewart A, Stewart AF, Svejstrup JQ. Mutation of cancer driver MLL2 results in transcription stress and genome instability. Genes Dev 2016; 30:408-20. [PMID: 26883360 PMCID: PMC4762426 DOI: 10.1101/gad.275453.115] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/15/2016] [Indexed: 12/12/2022]
Abstract
Genome instability is a recurring feature of tumorigenesis. Mutation in MLL2, encoding a histone methyltransferase, is a driver in numerous different cancer types, but the mechanism is unclear. Here, we present evidence that MLL2 mutation results in genome instability. Mouse cells in which MLL2 gene deletion can be induced display elevated levels of sister chromatid exchange, gross chromosomal aberrations, 53BP1 foci, and micronuclei. Human MLL2 knockout cells are characterized by genome instability as well. Interestingly, MLL2 interacts with RNA polymerase II (RNAPII) and RECQL5, and, although MLL2 mutated cells have normal overall H3K4me levels in genes, nucleosomes in the immediate vicinity of RNAPII are hypomethylated. Importantly, MLL2 mutated cells display signs of substantial transcription stress, and the most affected genes overlap with early replicating fragile sites, show elevated levels of γH2AX, and suffer frequent mutation. The requirement for MLL2 in the maintenance of genome stability in genes helps explain its widespread role in cancer and points to transcription stress as a strong driver in tumorigenesis.
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Affiliation(s)
- Theodoros Kantidakis
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN6 3LD, United Kingdom
| | - Marco Saponaro
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN6 3LD, United Kingdom
| | - Richard Mitter
- Bioinformatics and Biostatistics Group, The Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Stuart Horswell
- Bioinformatics and Biostatistics Group, The Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Andrea Kranz
- Biotechnologisches Zentrum, Technische Universität Dresden, 01062 Dresden, Germany
| | - Stefan Boeing
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN6 3LD, United Kingdom
| | - Ozan Aygün
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN6 3LD, United Kingdom
| | - Gavin P Kelly
- Bioinformatics and Biostatistics Group, The Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Nik Matthews
- Advanced Sequencing Facility, The Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Aengus Stewart
- Bioinformatics and Biostatistics Group, The Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - A Francis Stewart
- Biotechnologisches Zentrum, Technische Universität Dresden, 01062 Dresden, Germany
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN6 3LD, United Kingdom
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Linking replication stress with heterochromatin formation. Chromosoma 2015; 125:523-33. [PMID: 26511280 PMCID: PMC4901112 DOI: 10.1007/s00412-015-0545-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 09/27/2015] [Accepted: 09/30/2015] [Indexed: 11/23/2022]
Abstract
The eukaryotic genome can be roughly divided into euchromatin and heterochromatin domains that are structurally and functionally distinct. Heterochromatin is characterized by its high compaction that impedes DNA transactions such as gene transcription, replication, or recombination. Beyond its role in regulating DNA accessibility, heterochromatin plays essential roles in nuclear architecture, chromosome segregation, and genome stability. The formation of heterochromatin involves special histone modifications and the recruitment and spreading of silencing complexes that impact the higher-order structures of chromatin; however, its molecular nature varies between different chromosomal regions and between species. Although heterochromatin has been extensively characterized, its formation and maintenance throughout the cell cycle are not yet fully understood. The biggest challenge for the faithful transmission of chromatin domains is the destabilization of chromatin structures followed by their reassembly on a novel DNA template during genomic replication. This destabilizing event also provides a window of opportunity for the de novo establishment of heterochromatin. In recent years, it has become clear that different types of obstacles such as tight protein-DNA complexes, highly transcribed genes, and secondary DNA structures could impede the normal progression of the replisome and thus have the potential to endanger the integrity of the genome. Multiple studies carried out in different model organisms have demonstrated the capacity of such replisome impediments to favor the formation of heterochromatin. Our review summarizes these reports and discusses the potential role of replication stress in the formation and maintenance of heterochromatin and the role that silencing proteins could play at sites where the integrity of the genome is compromised.
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Nguyen PK, Lee WH, Li YF, Hong WX, Hu S, Chan C, Liang G, Nguyen I, Ong SG, Churko J, Wang J, Altman RB, Fleischmann D, Wu JC. Assessment of the Radiation Effects of Cardiac CT Angiography Using Protein and Genetic Biomarkers. JACC Cardiovasc Imaging 2015. [PMID: 26210695 DOI: 10.1016/j.jcmg.2015.04.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The purpose of this study was to evaluate whether radiation exposure from cardiac computed tomographic angiography (CTA) is associated with deoxyribonucleic acid (DNA) damage and whether damage leads to programmed cell death and activation of genes involved in apoptosis and DNA repair. BACKGROUND Exposure to radiation from medical imaging has become a public health concern, but whether it causes significant cell damage remains unclear. METHODS We conducted a prospective cohort study in 67 patients undergoing cardiac CTA between January 2012 and December 2013 in 2 U.S. medical centers. Median blood radiation exposure was estimated using phantom dosimetry. Biomarkers of DNA damage and apoptosis were measured by flow cytometry, whole genome sequencing, and single cell polymerase chain reaction. RESULTS The median dose length product was 1,535.3 mGy·cm (969.7 to 2,674.0 mGy·cm). The median radiation dose to the blood was 29.8 mSv (18.8 to 48.8 mSv). Median DNA damage increased 3.39% (1.29% to 8.04%, p < 0.0001) and median apoptosis increased 3.1-fold (interquartile range [IQR]: 1.4- to 5.1-fold, p < 0.0001) post-radiation. Whole genome sequencing revealed changes in the expression of 39 transcription factors involved in the regulation of apoptosis, cell cycle, and DNA repair. Genes involved in mediating apoptosis and DNA repair were significantly changed post-radiation, including DDB2 (1.9-fold [IQR: 1.5- to 3.0-fold], p < 0.001), XRCC4 (3.0-fold [IQR: 1.1- to 5.4-fold], p = 0.005), and BAX (1.6-fold [IQR: 0.9- to 2.6-fold], p < 0.001). Exposure to radiation was associated with DNA damage (odds ratio [OR]: 1.8 [1.2 to 2.6], p = 0.003). DNA damage was associated with apoptosis (OR: 1.9 [1.2 to 5.1], p < 0.0001) and gene activation (OR: 2.8 [1.2 to 6.2], p = 0.002). CONCLUSIONS Patients exposed to >7.5 mSv of radiation from cardiac CTA had evidence of DNA damage, which was associated with programmed cell death and activation of genes involved in apoptosis and DNA repair.
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Affiliation(s)
- Patricia K Nguyen
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Veterans Administration Palo Alto, Palo Alto, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California.
| | - Won Hee Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Yong Fuga Li
- Department of Genetics, Stanford University School of Medicine, Stanford, California
| | - Wan Xing Hong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Shijun Hu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Charles Chan
- Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Grace Liang
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Ivy Nguyen
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Sang-Ging Ong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Jared Churko
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - Jia Wang
- Environmental Health and Safety, Stanford University School of Medicine, Stanford, California
| | - Russ B Altman
- Department of Genetics, Stanford University School of Medicine, Stanford, California
| | - Dominik Fleischmann
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Radiology, Stanford University School of Medicine, Stanford, California
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California; Department of Radiology, Stanford University School of Medicine, Stanford, California.
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Hendriks IA, Treffers LW, Verlaan-de Vries M, Olsen JV, Vertegaal ACO. SUMO-2 Orchestrates Chromatin Modifiers in Response to DNA Damage. Cell Rep 2015; 10:1778-1791. [PMID: 25772364 DOI: 10.1016/j.celrep.2015.02.033] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 12/17/2014] [Accepted: 02/11/2015] [Indexed: 02/09/2023] Open
Abstract
Small ubiquitin-like modifiers play critical roles in the DNA damage response (DDR). To increase our understanding of SUMOylation in the mammalian DDR, we employed a quantitative proteomics approach in order to identify dynamically regulated SUMO-2 conjugates and modification sites upon treatment with the DNA damaging agent methyl methanesulfonate (MMS). We have uncovered a dynamic set of 20 upregulated and 33 downregulated SUMO-2 conjugates, and 755 SUMO-2 sites, of which 362 were dynamic in response to MMS. In contrast to yeast, where a response is centered on homologous recombination, we identified dynamically SUMOylated interaction networks of chromatin modifiers, transcription factors, DNA repair factors, and nuclear body components. SUMOylated chromatin modifiers include JARID1B/KDM5B, JARID1C/KDM5C, p300, CBP, PARP1, SetDB1, and MBD1. Whereas SUMOylated JARID1B was ubiquitylated by the SUMO-targeted ubiquitin ligase RNF4 and degraded by the proteasome in response to DNA damage, JARID1C was SUMOylated and recruited to the chromatin to demethylate histone H3K4.
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Affiliation(s)
- Ivo A Hendriks
- Department of Molecular Cell Biology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Louise W Treffers
- Department of Molecular Cell Biology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Matty Verlaan-de Vries
- Department of Molecular Cell Biology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Jesper V Olsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Alfred C O Vertegaal
- Department of Molecular Cell Biology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands.
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Gong F, Chiu LY, Cox B, Aymard F, Clouaire T, Leung JW, Cammarata M, Perez M, Agarwal P, Brodbelt JS, Legube G, Miller KM. Screen identifies bromodomain protein ZMYND8 in chromatin recognition of transcription-associated DNA damage that promotes homologous recombination. Genes Dev 2015; 29:197-211. [PMID: 25593309 PMCID: PMC4298138 DOI: 10.1101/gad.252189.114] [Citation(s) in RCA: 188] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Gong et al. report that more than one-third of human bromodomain (BRD)-containing proteins change localization in response to DNA damage. They identified ZMYND8 as a novel DNA damage response factor that recruits the nucleosome remodeling and histone deacetylation (NuRD) complex to damaged chromatin to repress transcription and promote repair by homologous recombination. How chromatin shapes pathways that promote genome–epigenome integrity in response to DNA damage is an issue of crucial importance. We report that human bromodomain (BRD)-containing proteins, the primary “readers” of acetylated chromatin, are vital for the DNA damage response (DDR). We discovered that more than one-third of all human BRD proteins change localization in response to DNA damage. We identified ZMYND8 (zinc finger and MYND [myeloid, Nervy, and DEAF-1] domain containing 8) as a novel DDR factor that recruits the nucleosome remodeling and histone deacetylation (NuRD) complex to damaged chromatin. Our data define a transcription-associated DDR pathway mediated by ZMYND8 and the NuRD complex that targets DNA damage, including when it occurs within transcriptionally active chromatin, to repress transcription and promote repair by homologous recombination. Thus, our data identify human BRD proteins as key chromatin modulators of the DDR and provide novel insights into how DNA damage within actively transcribed regions requires chromatin-binding proteins to orchestrate the appropriate response in concordance with the damage-associated chromatin context.
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Affiliation(s)
- Fade Gong
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Li-Ya Chiu
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Ben Cox
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - François Aymard
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université de Toulouse/Université Paul Sabatier, 31062 Toulouse, France. Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Centre National de la Recherche Scientifique (CNRS), 31062 Toulouse, France
| | - Thomas Clouaire
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université de Toulouse/Université Paul Sabatier, 31062 Toulouse, France. Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Centre National de la Recherche Scientifique (CNRS), 31062 Toulouse, France
| | - Justin W Leung
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Michael Cammarata
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - Mercedes Perez
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Poonam Agarwal
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - Gaëlle Legube
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université de Toulouse/Université Paul Sabatier, 31062 Toulouse, France. Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Centre National de la Recherche Scientifique (CNRS), 31062 Toulouse, France
| | - Kyle M Miller
- Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA;
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Sharma AK, Bhattacharya S, Khan SA, Khade B, Gupta S. Dynamic alteration in H3 serine 10 phosphorylation is G1-phase specific during ionization radiation induced DNA damage response in human cells. Mutat Res 2015; 773:83-91. [PMID: 25847424 DOI: 10.1016/j.mrfmmm.2015.01.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 12/22/2014] [Accepted: 01/28/2015] [Indexed: 12/26/2022]
Abstract
Chromatin acts as a natural barrier in DNA-damage recognition and repair. Histones undergo differential post-translational modification(s) to facilitate DNA damage response (DDR). Importance of modifications like phosphorylation of histone variant H2A.X in DNA repair is very well understood, however, ambiguous results exist in literature regarding the levels of certain histone modifications and their possible role in repair. In the present study, we have investigated in depth the alteration in the level of the highly dynamic histone mark H3S10P as it plays a dual role in different phases of the cell cycle. We show here that H3S10P decreases specifically from irradiated G1-enriched cells irrespective of the damaging agent or the cell line used in the study. Interestingly, the loss occurs predominantly from H3.3 variant which is a transcription activation mark like H3S10P itself, suggesting that the alteration might be implicated in transcription repression. The decrease in other transcription marks like H3K9Ac, H3K14Ac, H3K56Ac and H3S28P along with the occurrence of chromatin condensation in response to DNA damage in G1 phase strengthens the hypothesis. In addition, the alteration in the level of H3S10P shows an inverse correlation with that of γH2AX in a dose-dependent manner and probably occurs from the same mononucleosome. We propose that the drop in the levels of histone H3S10 phosphorylation is a universal phenomenon in response to DNA damage and is a trigger to induce transcription repressive state to facilitate repair.
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Affiliation(s)
- Ajit K Sharma
- Epigenetics and Chromatin Biology Group, Gupta Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Saikat Bhattacharya
- Epigenetics and Chromatin Biology Group, Gupta Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Shafqat A Khan
- Epigenetics and Chromatin Biology Group, Gupta Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Bharat Khade
- Epigenetics and Chromatin Biology Group, Gupta Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Sanjay Gupta
- Epigenetics and Chromatin Biology Group, Gupta Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India.
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Dicks N, Gutierrez K, Michalak M, Bordignon V, Agellon LB. Endoplasmic reticulum stress, genome damage, and cancer. Front Oncol 2015; 5:11. [PMID: 25692096 PMCID: PMC4315039 DOI: 10.3389/fonc.2015.00011] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/12/2015] [Indexed: 01/30/2023] Open
Abstract
Endoplasmic reticulum (ER) stress has been linked to many diseases, including cancer. A large body of work has focused on the activation of the ER stress response in cancer cells to facilitate their survival and tumor growth; however, there are some studies suggesting that the ER stress response can also mitigate cancer progression. Despite these contradictions, it is clear that the ER stress response is closely associated with cancer biology. The ER stress response classically encompasses activation of three separate pathways, which are collectively categorized the unfolded protein response (UPR). The UPR has been extensively studied in various cancers and appears to confer a selective advantage to tumor cells to facilitate their enhanced growth and resistance to anti-cancer agents. It has also been shown that ER stress induces chromatin changes, which can also facilitate cell survival. Chromatin remodeling has been linked with many cancers through repression of tumor suppressor and apoptosis genes. Interplay between the classic UPR and genome damage repair mechanisms may have important implications in the transformation process of normal cells into cancer cells.
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Affiliation(s)
- Naomi Dicks
- Department of Animal Science, McGill University , Montréal, QC , Canada
| | - Karina Gutierrez
- Department of Animal Science, McGill University , Montréal, QC , Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta , Edmonton, AB , Canada
| | - Vilceu Bordignon
- Department of Animal Science, McGill University , Montréal, QC , Canada
| | - Luis B Agellon
- School of Dietetics and Human Nutrition, McGill University , Montréal, QC , Canada
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Abstract
Rad26p is a SWI/SNF-like ATPase in yeast, and is conserved among eukaryotes. Both Rad26p and its human homolog CSB (Cockayne syndrome group B) are involved in regulation of chromatin structure, transcription and DNA repair. Thus, mutations or malfunctions of these proteins have significant effects on cellular functions. Mutations in CSB are associated with Cockayne syndrome (CS) that is characterized by heterogeneous pathologies such as mental and physical retardation, sun sensitivity, premature aging, muscular and skeletal abnormalities, and progressive decline in neurological and cognitive functions. Therefore, many research groups focused their studies to understand the mechanisms of Rad26p/CSB functions to illuminate the molecular bases of CS. These studies have provided significant functional and mechanistic insights of Rad26p/CSB in regulation of gene expression and genome integrity as described here.
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Affiliation(s)
- Shivani Malik
- a Department of Biochemistry and Molecular Biology ; Southern Illinois University School of Medicine ; Carbondale , IL USA
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Barlow JH, Nussenzweig A. Replication initiation and genome instability: a crossroads for DNA and RNA synthesis. Cell Mol Life Sci 2014; 71:4545-59. [PMID: 25238783 DOI: 10.1007/s00018-014-1721-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/28/2014] [Indexed: 12/16/2022]
Abstract
Nuclear DNA replication requires the concerted action of hundreds of proteins to efficiently unwind and duplicate the entire genome while also retaining epigenetic regulatory information. Initiation of DNA replication is tightly regulated, rapidly firing thousands of origins once the conditions to promote rapid and faithful replication are in place, and defects in replication initiation lead to proliferation defects, genome instability, and a range of developmental abnormalities. Interestingly, DNA replication in metazoans initiates in actively transcribed DNA, meaning that replication initiation occurs in DNA that is co-occupied with tens of thousands of poised and active RNA polymerase complexes. Active transcription can induce genome instability, particularly during DNA replication, as RNA polymerases can induce torsional stress, formation of secondary structures, and act as a physical barrier to other enzymes involved in DNA metabolism. Here we discuss the challenges facing mammalian DNA replication, their impact on genome instability, and the development of cancer.
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Blurring the line between the DNA damage response and transcription: the importance of chromatin dynamics. Exp Cell Res 2014; 329:148-53. [PMID: 25062983 PMCID: PMC5111725 DOI: 10.1016/j.yexcr.2014.07.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 01/18/2023]
Abstract
DNA damage interferes with the progression of transcription machineries. A tight coordination of transcription with signaling and repair of DNA damage is thus critical for safeguarding genome function. This coordination involves modulations of chromatin organization. Here, we focus on the central role of chromatin dynamics, in conjunction with DNA Damage Response (DDR) factors, in controlling transcription inhibition and restart at sites of DNA damage in mammalian cells. Recent work has identified chromatin modifiers and histone chaperones as key regulators of transcriptional activity in damaged chromatin regions. Conversely, the transcriptional state of chromatin before DNA damage influences both DNA damage signaling and repair. We discuss the importance of chromatin plasticity in coordinating the interplay between the DDR and transcription, with major implications for cell fate maintenance.
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Hamperl S, Cimprich KA. The contribution of co-transcriptional RNA:DNA hybrid structures to DNA damage and genome instability. DNA Repair (Amst) 2014; 19:84-94. [PMID: 24746923 PMCID: PMC4051866 DOI: 10.1016/j.dnarep.2014.03.023] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Accurate DNA replication and DNA repair are crucial for the maintenance of genome stability, and it is generally accepted that failure of these processes is a major source of DNA damage in cells. Intriguingly, recent evidence suggests that DNA damage is more likely to occur at genomic loci with high transcriptional activity. Furthermore, loss of certain RNA processing factors in eukaryotic cells is associated with increased formation of co-transcriptional RNA:DNA hybrid structures known as R-loops, resulting in double-strand breaks (DSBs) and DNA damage. However, the molecular mechanisms by which R-loop structures ultimately lead to DNA breaks and genome instability is not well understood. In this review, we summarize the current knowledge about the formation, recognition and processing of RNA:DNA hybrids, and discuss possible mechanisms by which these structures contribute to DNA damage and genome instability in the cell.
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Affiliation(s)
- Stephan Hamperl
- Department of Chemical, Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA
| | - Karlene A Cimprich
- Department of Chemical, Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
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Adam S, Polo SE, Almouzni G. How to restore chromatin structure and function in response to DNA damage--let the chaperones play: delivered on 9 July 2013 at the 38th FEBS Congress in St Petersburg, Russia. FEBS J 2014; 281:2315-23. [PMID: 24673849 DOI: 10.1111/febs.12793] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/25/2014] [Indexed: 01/07/2023]
Abstract
Histone deposition onto DNA assisted by specific chaperones forms the chromatin basic unit and serves to package the genome within the cell nucleus. The resulting chromatin organization, often referred to as the epigenome, contributes to a unique transcriptional program that defines cell identity. Importantly, during cellular life, substantial alterations in chromatin structure may arise due to cell stress, including DNA damage, which not only challenges the integrity of the genome but also threatens the epigenome. Considerable efforts have been made to decipher chromatin dynamics in response to genotoxic stress, and to assess how it affects both genome and epigenome stability. Here, we review recent advances in understanding the mechanisms of DNA damage-induced chromatin plasticity in mammalian cells. We focus specifically on the dynamics of histone H3 variants in response to UV irradiation, and highlight the role of their dedicated chaperones in restoring both chromatin structure and function. Finally, we discuss how, in addition to restoring chromatin integrity, the cellular networks that signal and repair DNA damage may also provide a window of opportunity for modulating the information conveyed by chromatin.
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Affiliation(s)
- Salomé Adam
- Institut Curie, Centre de Recherche, Paris, France; Centre National de la Recherche Scientifique, UMR3664, Paris, France; Equipe Labellisée Ligue Contre le Cancer, Paris, France; Institut de Formation Doctorale, University Pierre & Marie Curie, Paris, France; Sorbonne University, PSL*, Paris, France; Epigenetics and Cell Fate Centre, UMR7216, Centre National de la Recherche Scientifique/Paris Diderot University, Paris, France
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Adam S, Polo SE, Almouzni G. Transcription recovery after DNA damage requires chromatin priming by the H3.3 histone chaperone HIRA. Cell 2013; 155:94-106. [PMID: 24074863 DOI: 10.1016/j.cell.2013.08.029] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/17/2013] [Accepted: 08/16/2013] [Indexed: 10/26/2022]
Abstract
Understanding how to recover fully functional and transcriptionally active chromatin when its integrity has been challenged by genotoxic stress is a critical issue. Here, by investigating how chromatin dynamics regulate transcriptional activity in response to DNA damage in human cells, we identify a pathway involving the histone chaperone histone regulator A (HIRA) to promote transcription restart after UVC damage. Our mechanistic studies reveal that HIRA accumulates at sites of UVC irradiation upon detection of DNA damage prior to repair and deposits newly synthesized H3.3 histones. This local action of HIRA depends on ubiquitylation events associated with damage recognition. Furthermore, we demonstrate that the early and transient function of HIRA in response to DNA damage primes chromatin for later reactivation of transcription. We propose that HIRA-dependent histone deposition serves as a chromatin bookmarking system to facilitate transcription recovery after genotoxic stress.
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Affiliation(s)
- Salomé Adam
- Chromatin Dynamics, Institut Curie Research Centre, 75248 Paris Cedex 5, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 218, 75248 Paris Cedex 5, France
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Sun J, Keim CD, Wang J, Kazadi D, Oliver PM, Rabadan R, Basu U. E3-ubiquitin ligase Nedd4 determines the fate of AID-associated RNA polymerase II in B cells. Genes Dev 2013; 27:1821-33. [PMID: 23964096 PMCID: PMC3759698 DOI: 10.1101/gad.210211.112] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Programmed mutagenesis of the immunoglobulin locus of B lymphocytes during class switch recombination (CSR) and somatic hypermutation requires RNA polymerase II (polII) transcription complex-dependent targeting of the DNA mutator activation-induced cytidine deaminase (AID). AID deaminates cytidine residues on substrate sequences in the immunoglobulin (Ig) locus via a transcription-dependent mechanism, and this activity is stimulated by the RNA polII stalling cofactor Spt5 and the 11-subunit cellular noncoding RNA 3'-5' exonucleolytic processing complex RNA exosome. The mechanism by which the RNA exosome recognizes immunoglobulin locus RNA substrates to stimulate AID DNA deamination activity on its in vivo substrate sequences is an important question. Here we report that E3-ubiquitin ligase Nedd4 destabilizes AID-associated RNA polII by a ubiquitination event, leading to generation of 3' end free RNA exosome RNA substrates at the Ig locus and other AID target sequences genome-wide. We found that lack of Nedd4 activity in B cells leads to accumulation of RNA exosome substrates at AID target genes and defective CSR. Taken together, our study links noncoding RNA processing following RNA polII pausing with regulation of the mutator AID protein. Our study also identifies Nedd4 as a regulator of noncoding RNAs that are generated by stalled RNA polII genome-wide.
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Affiliation(s)
- Jianbo Sun
- Department of Microbiology and Immunology, Columbia University, New York, New York 10032, USA
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Wilson MD, Harreman M, Taschner M, Reid J, Walker J, Erdjument-Bromage H, Tempst P, Svejstrup JQ. Proteasome-mediated processing of Def1, a critical step in the cellular response to transcription stress. Cell 2013; 154:983-995. [PMID: 23993092 PMCID: PMC3778974 DOI: 10.1016/j.cell.2013.07.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 05/30/2013] [Accepted: 07/19/2013] [Indexed: 11/25/2022]
Abstract
DNA damage triggers polyubiquitylation and degradation of the largest subunit of RNA polymerase II (RNAPII), a "mechanism of last resort" employed during transcription stress. In yeast, this process is dependent on Def1 through a previously unresolved mechanism. Here, we report that Def1 becomes activated through ubiquitylation- and proteasome-dependent processing. Def1 processing results in the removal of a domain promoting cytoplasmic localization, resulting in nuclear accumulation of the clipped protein. Nuclear Def1 then binds RNAPII, utilizing a ubiquitin-binding domain to recruit the Elongin-Cullin E3 ligase complex via a ubiquitin-homology domain in the Ela1 protein. This facilitates polyubiquitylation of Rpb1, triggering its proteasome-mediated degradation. Together, these results outline the multistep mechanism of Rpb1 polyubiquitylation triggered by transcription stress and uncover the key role played by Def1 as a facilitator of Elongin-Cullin ubiquitin ligase function.
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Affiliation(s)
- Marcus D Wilson
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK
| | - Michelle Harreman
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK
| | - Michael Taschner
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK
| | - James Reid
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK
| | - Jane Walker
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK
| | - Hediye Erdjument-Bromage
- Molecular Biology Programme, Memorial Sloan-Kettering Cancer Center, York Avenue 1275, New York, NY 10021, USA
| | - Paul Tempst
- Molecular Biology Programme, Memorial Sloan-Kettering Cancer Center, York Avenue 1275, New York, NY 10021, USA
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK.
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Kimura H, Shimooka Y, Nishikawa JI, Miura O, Sugiyama S, Yamada S, Ohyama T. The genome folding mechanism in yeast. ACTA ACUST UNITED AC 2013; 154:137-47. [DOI: 10.1093/jb/mvt033] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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43
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Gaillard H, Herrera-Moyano E, Aguilera A. Transcription-associated genome instability. Chem Rev 2013; 113:8638-61. [PMID: 23597121 DOI: 10.1021/cr400017y] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla , Av. Américo Vespucio s/n, 41092 Seville, Spain
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Winsor TS, Bartkowiak B, Bennett CB, Greenleaf AL. A DNA damage response system associated with the phosphoCTD of elongating RNA polymerase II. PLoS One 2013; 8:e60909. [PMID: 23613755 PMCID: PMC3629013 DOI: 10.1371/journal.pone.0060909] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/04/2013] [Indexed: 01/22/2023] Open
Abstract
RNA polymerase II translocates across much of the genome and since it can be blocked by many kinds of DNA lesions, detects DNA damage proficiently; it thereby contributes to DNA repair and to normal levels of DNA damage resistance. However, the components and mechanisms that respond to polymerase blockage are largely unknown, except in the case of UV-induced damage that is corrected by nucleotide excision repair. Because elongating RNAPII carries with it numerous proteins that bind to its hyperphosphorylated CTD, we tested for effects of interfering with this binding. We find that expressing a decoy CTD-carrying protein in the nucleus, but not in the cytoplasm, leads to reduced DNA damage resistance. Likewise, inducing aberrant phosphorylation of the CTD, by deleting CTK1, reduces damage resistance and also alters rates of homologous recombination-mediated repair. In line with these results, extant data sets reveal a remarkable, highly significant overlap between phosphoCTD-associating protein genes and DNA damage-resistance genes. For one well-known phosphoCTD-associating protein, the histone methyltransferase Set2, we demonstrate a role in DNA damage resistance, and we show that this role requires the phosphoCTD binding ability of Set2; surprisingly, Set2’s role in damage resistance does not depend on its catalytic activity. To explain all of these observations, we posit the existence of a CTD-Associated DNA damage Response (CAR) system, organized around the phosphoCTD of elongating RNAPII and comprising a subset of phosphoCTD-associating proteins.
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Affiliation(s)
- Tiffany Sabin Winsor
- Department of Biochemistry, Duke Center for RNA Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Bartlomiej Bartkowiak
- Department of Biochemistry, Duke Center for RNA Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Craig B. Bennett
- Department of Biochemistry, Duke Center for RNA Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Arno L. Greenleaf
- Department of Biochemistry, Duke Center for RNA Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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45
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Affiliation(s)
- Helle D Ulrich
- Cancer Research UK London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, Hertfordshire EN6 3LD, UK.
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46
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Li J, Luthra S, Wang XH, Chandran UR, Sobol RW. Transcriptional profiling reveals elevated Sox2 in DNA polymerase ß null mouse embryonic fibroblasts. Am J Cancer Res 2012; 2:699-713. [PMID: 23226616 DOI: 10.1158/1538-7445.am2012-699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 11/02/2012] [Indexed: 11/16/2022] Open
Abstract
There are over 150 human proteins that have been categorized as bona fide DNA repair proteins. These DNA repair proteins maintain the integrity of the genome, reducing the onset of cancer, disease and aging phenotypes. Variations in expression and/or function would therefore impact genome integrity as well as the cellular response to genotoxins. Global gene expression analysis is an effective approach to uncover defects in DNA repair gene expression and to discover cellular and/or organismal effects brought about by external stimuli such as environmental genotoxicants, chemotherapeutic regimens, viral infections as well as developmental and age-related stimuli. Given the significance of genome stability in cell survival and response to stimuli, we have hypothesized that cells may undergo transcriptional re-programming to accommodate defects in basal DNA repair capacity to promote survival. As a test of this hypothesis, we have compared the transcriptome in three DNA polymerase ß knockout (Polß-KO) mouse embryonic fibroblasts (MEFs) and the corresponding wild-type (WT) littermate control cell lines. Each Polß-KO cell line was found to have a range of genes up-regulated, when compared to its WT littermate control cell line. Interestingly, six (6) genes were commonly up regulated in all three Polß-KO cell lines, including Sox2, one of several genes associated with the induction of pluripotent stem cells. Herein, we present these findings and suggest that loss of DNA repair and the induction of cellular transcriptional re-programming may, in part, contribute to tumor formation and the cellular response to external stimuli.
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Affiliation(s)
- Jianfeng Li
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15213, USA ; University of Pittsburgh Cancer Institute, Hillman Cancer Center Pittsburgh, PA 15213, USA
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Finley D, Ulrich HD, Sommer T, Kaiser P. The ubiquitin-proteasome system of Saccharomyces cerevisiae. Genetics 2012; 192:319-60. [PMID: 23028185 PMCID: PMC3454868 DOI: 10.1534/genetics.112.140467] [Citation(s) in RCA: 301] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/28/2012] [Indexed: 12/14/2022] Open
Abstract
Protein modifications provide cells with exquisite temporal and spatial control of protein function. Ubiquitin is among the most important modifiers, serving both to target hundreds of proteins for rapid degradation by the proteasome, and as a dynamic signaling agent that regulates the function of covalently bound proteins. The diverse effects of ubiquitylation reflect the assembly of structurally distinct ubiquitin chains on target proteins. The resulting ubiquitin code is interpreted by an extensive family of ubiquitin receptors. Here we review the components of this regulatory network and its effects throughout the cell.
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Affiliation(s)
- Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Helle D. Ulrich
- Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, EN6 3LD, United Kingdom
| | - Thomas Sommer
- Max-Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Peter Kaiser
- Department of Biological Chemistry, University of California, Irvine, California 92697
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Michalik KM, Böttcher R, Förstemann K. A small RNA response at DNA ends in Drosophila. Nucleic Acids Res 2012; 40:9596-603. [PMID: 22848104 PMCID: PMC3479179 DOI: 10.1093/nar/gks711] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Small RNAs have been implicated in numerous cellular processes, including effects on chromatin structure and the repression of transposons. We describe the generation of a small RNA response at DNA ends in Drosophila that is analogous to the recently reported double-strand break (DSB)-induced RNAs or Dicer- and Drosha-dependent small RNAs in Arabidopsis and vertebrates. Active transcription in the vicinity of the break amplifies this small RNA response, demonstrating that the normal messenger RNA contributes to the endogenous small interfering RNAs precursor. The double-stranded RNA precursor forms with an antisense transcript that initiates at the DNA break. Breaks are thus sites of transcription initiation, a novel aspect of the cellular DSB response. This response is specific to a double-strand break since nicked DNA structures do not trigger small RNA production. The small RNAs are generated independently of the exact end structure (blunt, 3'- or 5'-overhang), can repress homologous sequences in trans and may therefore--in addition to putative roles in repair--exert a quality control function by clearing potentially truncated messages from genes in the vicinity of the break.
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Affiliation(s)
- Katharina M Michalik
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, München, Germany
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49
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Hendriks G, Jansen JG, Mullenders LHF, de Wind N. Transcription-coupled repair and apoptosis provide specific protection against transcription-associated mutagenesis by ultraviolet light. Transcription 2012; 1:95-8. [PMID: 21326899 DOI: 10.4161/trns.1.2.12788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 06/14/2010] [Accepted: 06/25/2010] [Indexed: 12/14/2022] Open
Abstract
Recent data reveal that gene transcription affects genome stability in mammalian cells. For example, transcription of DNA that is damaged by the most prevalent exogenous genotoxin, UV light, induces nucleotide substitutions and chromosomal instability, collectively called UV-induced transcription-associated mutations (UV-TAM). An important class of UV-TAM consists of nucleotide transitions that are caused by deamination of cytosine-containing photolesions to uracil, presumably occurring at stalled transcription complexes. Transcription-associated deletions and recombinational events after UV exposure may be triggered by collisions of replication forks with stalled transcription complexes. In this Point-of-View we propose that mammalian cells possess two tailored mechanisms to prevent UV-TAM in dermal stem cells. First, the transcription-coupled nucleotide excision repair (TCR) pathway removes lesions at transcribed DNA strands, forming the primary barrier against the mutagenic consequences of transcription at a damaged template. Second, when TCR is absent or when the capacity of TCR is exceeded, persistently stalled transcription complexes induce apoptosis, averting the generation of mutant cells following replication. We hypothesize that TCR and the apoptotic response in conjunction reduce the risk of skin carcinogenesis.
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50
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MS_RHII-RSD, a dual-function RNase HII-(p)ppGpp synthetase from Mycobacterium smegmatis. J Bacteriol 2012; 194:4003-14. [PMID: 22636779 DOI: 10.1128/jb.00258-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In the noninfectious soil saprophyte Mycobacterium smegmatis, intracellular levels of the stress alarmones guanosine tetraphosphate and guanosine pentaphosphate, together termed (p)ppGpp, are regulated by the enzyme Rel(Msm). This enzyme consists of a single, bifunctional polypeptide chain that is capable of both synthesizing and hydrolyzing (p)ppGpp. The rel(Msm) knockout strain of M. smegmatis (Δrel(Msm)) is expected to show a (p)ppGpp null [(p)ppGpp(0)] phenotype. Contrary to this expectation, the strain is capable of synthesizing (p)ppGpp in vivo. In this study, we identify and functionally characterize the open reading frame (ORF), MSMEG_5849, that encodes a second functional (p)ppGpp synthetase in M. smegmatis. In addition to (p)ppGpp synthesis, the 567-amino-acid-long protein encoded by this gene is capable of hydrolyzing RNA·DNA hybrids and bears similarity to the conventional RNase HII enzymes. We have classified this protein as actRel(Msm) in accordance with the recent nomenclature proposed and have named it MS_RHII-RSD, indicating the two enzymatic activities present [RHII, RNase HII domain, originally identified as domain of unknown function 429 (DUF429), and RSD, RelA_SpoT nucleotidyl transferase domain, the SYNTH domain responsible for (p)ppGpp synthesis activity]. MS_RHII-RSD is expressed and is constitutively active in vivo and behaves like a monofunctional (p)ppGpp synthetase in vitro. The occurrence of the RNase HII and (p)ppGpp synthetase domains together on the same polypeptide chain is suggestive of an in vivo role for this novel protein as a link connecting the essential life processes of DNA replication, repair, and transcription to the highly conserved stress survival pathway, the stringent response.
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