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Kendek A, Sandron A, Lambooij JP, Colmenares SU, Pociunaite SM, Gooijers I, de Groot L, Karpen GH, Janssen A. DNA double-strand break movement in heterochromatin depends on the histone acetyltransferase dGcn5. Nucleic Acids Res 2024:gkae775. [PMID: 39258543 DOI: 10.1093/nar/gkae775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 08/20/2024] [Accepted: 08/26/2024] [Indexed: 09/12/2024] Open
Abstract
Cells employ diverse strategies to repair double-strand breaks (DSBs), a dangerous form of DNA damage that threatens genome integrity. Eukaryotic nuclei consist of different chromatin environments, each displaying distinct molecular and biophysical properties that can significantly influence the DSB-repair process. DSBs arising in the compact and silenced heterochromatin domains have been found to move to the heterochromatin periphery in mouse and Drosophila to prevent aberrant recombination events. However, it is poorly understood how chromatin components, such as histone post-translational modifications, contribute to these DSB movements within heterochromatin. Using irradiation as well as locus-specific DSB induction in Drosophila tissues and cultured cells, we find enrichment of histone H3 lysine 9 acetylation (H3K9ac) at DSBs in heterochromatin but not euchromatin. We find this increase is mediated by the histone acetyltransferase dGcn5, which rapidly localizes to heterochromatic DSBs. Moreover, we demonstrate that in the absence of dGcn5, heterochromatic DSBs display impaired recruitment of the SUMO E3 ligase Nse2/Qjt and fail to relocate to the heterochromatin periphery to complete repair. In summary, our results reveal a previously unidentified role for dGcn5 and H3K9ac in heterochromatic DSB repair and underscore the importance of differential chromatin responses at heterochromatic and euchromatic DSBs to promote safe repair.
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Affiliation(s)
- Apfrida Kendek
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Arianna Sandron
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Jan-Paul Lambooij
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Serafin U Colmenares
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, Berkeley, California, USA
| | - Severina M Pociunaite
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Iris Gooijers
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Lars de Groot
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, Berkeley, California, USA
- Division of Biological Sciences and the Environment, Lawrence Berkeley National Laboratory, CA 94720, Berkeley, California, USA
| | - Aniek Janssen
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, the Netherlands
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2
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Caeiro LD, Verdun RE, Morey L. Histone H3 mutations and their impact on genome stability maintenance. Biochem Soc Trans 2024:BST20240177. [PMID: 39248209 DOI: 10.1042/bst20240177] [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: 06/26/2024] [Revised: 08/13/2024] [Accepted: 08/27/2024] [Indexed: 09/10/2024]
Abstract
Histones are essential for maintaining chromatin structure and function. Histone mutations lead to changes in chromatin compaction, gene expression, and the recruitment of DNA repair proteins to the DNA lesion. These disruptions can impair critical DNA repair pathways, such as homologous recombination and non-homologous end joining, resulting in increased genomic instability, which promotes an environment favorable to tumor development and progression. Understanding these mechanisms underscores the potential of targeting DNA repair pathways in cancers harboring mutated histones, offering novel therapeutic strategies to exploit their inherent genomic instability for better treatment outcomes. Here, we examine how mutations in histone H3 disrupt normal chromatin function and DNA damage repair processes and how these mechanisms can be exploited for therapeutic interventions.
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Affiliation(s)
- Lucas D Caeiro
- Sylvester Comprehensive Cancer Center, Biomedical Research Building, 1501 NW 10th Avenue, Miami, FL 33136, U.S.A
- Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, U.S.A
| | - Ramiro E Verdun
- Sylvester Comprehensive Cancer Center, Biomedical Research Building, 1501 NW 10th Avenue, Miami, FL 33136, U.S.A
- Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, U.S.A
- Geriatric Research, Education, and Clinical Center, Miami VA Healthcare System, Miami, FL, U.S.A
| | - Lluis Morey
- Sylvester Comprehensive Cancer Center, Biomedical Research Building, 1501 NW 10th Avenue, Miami, FL 33136, U.S.A
- Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, U.S.A
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3
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Schep R, Trauernicht M, Vergara X, Friskes A, Morris B, Gregoricchio S, Manzo SG, Zwart W, Beijersbergen R, Medema RH, van Steensel B. Chromatin context-dependent effects of epigenetic drugs on CRISPR-Cas9 editing. Nucleic Acids Res 2024; 52:8815-8832. [PMID: 38953163 PMCID: PMC11347147 DOI: 10.1093/nar/gkae570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/13/2024] [Accepted: 06/19/2024] [Indexed: 07/03/2024] Open
Abstract
The efficiency and outcome of CRISPR/Cas9 editing depends on the chromatin state at the cut site. It has been shown that changing the chromatin state can influence both the efficiency and repair outcome, and epigenetic drugs have been used to improve Cas9 editing. However, because the target proteins of these drugs are not homogeneously distributed across the genome, the efficacy of these drugs may be expected to vary from locus to locus. Here, we systematically analyzed this chromatin context-dependency for 160 epigenetic drugs. We used a human cell line with 19 stably integrated reporters to induce a double-stranded break in different chromatin environments. We then measured Cas9 editing efficiency and repair pathway usage by sequencing the mutational signatures. We identified 58 drugs that modulate Cas9 editing efficiency and/or repair outcome dependent on the local chromatin environment. For example, we find a subset of histone deacetylase inhibitors that improve Cas9 editing efficiency throughout all types of heterochromatin (e.g. PCI-24781), while others were only effective in euchromatin and H3K27me3-marked regions (e.g. apicidin). In summary, this study reveals that most epigenetic drugs alter CRISPR editing in a chromatin-dependent manner, and provides a resource to improve Cas9 editing more selectively at the desired location.
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Affiliation(s)
- Ruben Schep
- Oncode Institute, The Netherlands
- Division of Molecular Genetics, 1066 CX Amsterdam, The Netherlands
| | - Max Trauernicht
- Oncode Institute, The Netherlands
- Division of Molecular Genetics, 1066 CX Amsterdam, The Netherlands
| | - Xabier Vergara
- Oncode Institute, The Netherlands
- Division of Molecular Genetics, 1066 CX Amsterdam, The Netherlands
- Division of Cell Biology, 1066 CX Amsterdam, The Netherlands
| | - Anoek Friskes
- Oncode Institute, The Netherlands
- Division of Cell Biology, 1066 CX Amsterdam, The Netherlands
| | - Ben Morris
- Division of Molecular Carcinogenesis, 1066 CX Amsterdam, The Netherlands
| | - Sebastian Gregoricchio
- Oncode Institute, The Netherlands
- Division of Oncogenomics, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Stefano G Manzo
- Oncode Institute, The Netherlands
- Division of Molecular Genetics, 1066 CX Amsterdam, The Netherlands
| | - Wilbert Zwart
- Oncode Institute, The Netherlands
- Division of Oncogenomics, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - René H Medema
- Oncode Institute, The Netherlands
- Division of Cell Biology, 1066 CX Amsterdam, The Netherlands
| | - Bas van Steensel
- Oncode Institute, The Netherlands
- Division of Molecular Genetics, 1066 CX Amsterdam, The Netherlands
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4
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Bakr A, Corte GD, Veselinov O, Kelekçi S, Chen MJM, Lin YY, Sigismondo G, Iacovone M, Cross A, Syed R, Jeong Y, Sollier E, Liu CS, Lutsik P, Krijgsveld J, Weichenhan D, Plass C, Popanda O, Schmezer P. ARID1A regulates DNA repair through chromatin organization and its deficiency triggers DNA damage-mediated anti-tumor immune response. Nucleic Acids Res 2024; 52:5698-5719. [PMID: 38587186 PMCID: PMC11162808 DOI: 10.1093/nar/gkae233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/27/2024] [Accepted: 03/21/2024] [Indexed: 04/09/2024] Open
Abstract
AT-rich interaction domain protein 1A (ARID1A), a SWI/SNF chromatin remodeling complex subunit, is frequently mutated across various cancer entities. Loss of ARID1A leads to DNA repair defects. Here, we show that ARID1A plays epigenetic roles to promote both DNA double-strand breaks (DSBs) repair pathways, non-homologous end-joining (NHEJ) and homologous recombination (HR). ARID1A is accumulated at DSBs after DNA damage and regulates chromatin loops formation by recruiting RAD21 and CTCF to DSBs. Simultaneously, ARID1A facilitates transcription silencing at DSBs in transcriptionally active chromatin by recruiting HDAC1 and RSF1 to control the distribution of activating histone marks, chromatin accessibility, and eviction of RNAPII. ARID1A depletion resulted in enhanced accumulation of micronuclei, activation of cGAS-STING pathway, and an increased expression of immunomodulatory cytokines upon ionizing radiation. Furthermore, low ARID1A expression in cancer patients receiving radiotherapy was associated with higher infiltration of several immune cells. The high mutation rate of ARID1A in various cancer types highlights its clinical relevance as a promising biomarker that correlates with the level of immune regulatory cytokines and estimates the levels of tumor-infiltrating immune cells, which can predict the response to the combination of radio- and immunotherapy.
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Affiliation(s)
- Ali Bakr
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Giuditta Della Corte
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Olivera Veselinov
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Simge Kelekçi
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Mei-Ju May Chen
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Yu-Yu Lin
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Gianluca Sigismondo
- Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), INF581, 69120 Heidelberg, Germany
| | - Marika Iacovone
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Alice Cross
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Rabail Syed
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Yunhee Jeong
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Etienne Sollier
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Chun- Shan Liu
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Pavlo Lutsik
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Jeroen Krijgsveld
- Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), INF581, 69120 Heidelberg, Germany
- Heidelberg University, Medical Faculty, Heidelberg, Germany
| | - Dieter Weichenhan
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Christoph Plass
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), INF280, 69120 Heidelberg, Germany
| | - Odilia Popanda
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
| | - Peter Schmezer
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
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5
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Chen R, Zhao MJ, Li YM, Liu AH, Wang RX, Mei YC, Chen X, Du HN. Di- and tri-methylation of histone H3K36 play distinct roles in DNA double-strand break repair. SCIENCE CHINA. LIFE SCIENCES 2024; 67:1089-1105. [PMID: 38842635 DOI: 10.1007/s11427-024-2543-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 06/07/2024]
Abstract
Histone H3 Lys36 (H3K36) methylation and its associated modifiers are crucial for DNA double-strand break (DSB) repair, but the mechanism governing whether and how different H3K36 methylation forms impact repair pathways is unclear. Here, we unveil the distinct roles of H3K36 dimethylation (H3K36me2) and H3K36 trimethylation (H3K36me3) in DSB repair via non-homologous end joining (NHEJ) or homologous recombination (HR). Yeast cells lacking H3K36me2 or H3K36me3 exhibit reduced NHEJ or HR efficiency. yKu70 and Rfa1 bind H3K36me2- or H3K36me3-modified peptides and chromatin, respectively. Disrupting these interactions impairs yKu70 and Rfa1 recruitment to damaged H3K36me2- or H3K36me3-rich loci, increasing DNA damage sensitivity and decreasing repair efficiency. Conversely, H3K36me2-enriched intergenic regions and H3K36me3-enriched gene bodies independently recruit yKu70 or Rfa1 under DSB stress. Importantly, human KU70 and RPA1, the homologs of yKu70 and Rfa1, exclusively associate with H3K36me2 and H3K36me3 in a conserved manner. These findings provide valuable insights into how H3K36me2 and H3K36me3 regulate distinct DSB repair pathways, highlighting H3K36 methylation as a critical element in the choice of DSB repair pathway.
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Affiliation(s)
- Runfa Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Meng-Jie Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Yu-Min Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Ao-Hui Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Ru-Xin Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Yu-Chao Mei
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, 430072, China
| | - Hai-Ning Du
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Frontier Science Center for Immunology and Metabolism, Hubei Clinical Research Center of Emergency and Resuscitation, Emergency Center of Zhongnan Hospital, Wuhan University, Wuhan, 430072, China.
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6
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Herrick J. DNA Damage, Genome Stability, and Adaptation: A Question of Chance or Necessity? Genes (Basel) 2024; 15:520. [PMID: 38674454 PMCID: PMC11049855 DOI: 10.3390/genes15040520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/14/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
DNA damage causes the mutations that are the principal source of genetic variation. DNA damage detection and repair mechanisms therefore play a determining role in generating the genetic diversity on which natural selection acts. Speciation, it is commonly assumed, occurs at a rate set by the level of standing allelic diversity in a population. The process of speciation is driven by a combination of two evolutionary forces: genetic drift and ecological selection. Genetic drift takes place under the conditions of relaxed selection, and results in a balance between the rates of mutation and the rates of genetic substitution. These two processes, drift and selection, are necessarily mediated by a variety of mechanisms guaranteeing genome stability in any given species. One of the outstanding questions in evolutionary biology concerns the origin of the widely varying phylogenetic distribution of biodiversity across the Tree of Life and how the forces of drift and selection contribute to shaping that distribution. The following examines some of the molecular mechanisms underlying genome stability and the adaptive radiations that are associated with biodiversity and the widely varying species richness and evenness in the different eukaryotic lineages.
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Affiliation(s)
- John Herrick
- Independent Researcher at 3, Rue des Jeûneurs, 75002 Paris, France
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7
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Mondal A, Sarkar A, Das D, Sengupta A, Kabiraj A, Mondal P, Nag R, Mukherjee S, Das C. Epigenetic orchestration of the DNA damage response: Insights into the regulatory mechanisms. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2024; 387:99-141. [PMID: 39179350 DOI: 10.1016/bs.ircmb.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2024]
Abstract
The DNA damage response (DDR) is a critical cellular mechanism that safeguards genome integrity and prevents the accumulation of harmful DNA lesions. Increasing evidence highlights the intersection between DDR signaling and epigenetic regulation, offering profound insights into various aspects of cellular function including oncogenesis. This comprehensive review explores the intricate relationship between the epigenetic modifications and DDR activation, with a specific focus on the impact of viral infections. Oncogenic viruses, such as human papillomavirus, hepatitis virus (HBV or HCV), and Epstein-Barr virus have been shown to activate the DDR. Consequently, these DNA damage events trigger a cascade of epigenetic alterations, including changes in DNA methylation patterns, histone modifications and the expression of noncoding RNAs. These epigenetic changes exert profound effects on chromatin structure, gene expression, and maintenance of genome stability. Importantly, elucidation of the viral-induced epigenetic alterations in the context of DDR holds significant implications for comprehending the complexity of cancer and provides potential targets for therapeutic interventions.
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Affiliation(s)
- Atanu Mondal
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Mumbai, India
| | | | - Dipanwita Das
- Virus Unit [NICED-ICMR], ID and BG Hospital, Kolkata, India
| | - Amrita Sengupta
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India
| | - Aindrila Kabiraj
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Mumbai, India
| | - Payel Mondal
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Mumbai, India
| | - Rachayita Nag
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Mumbai, India
| | - Shravanti Mukherjee
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India
| | - Chandrima Das
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Mumbai, India.
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8
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Gómez-González B, Aguilera A. Break-induced RNA-DNA hybrids (BIRDHs) in homologous recombination: friend or foe? EMBO Rep 2023; 24:e57801. [PMID: 37818834 DOI: 10.15252/embr.202357801] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/29/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023] Open
Abstract
Double-strand breaks (DSBs) are the most harmful DNA lesions, with a strong impact on cell proliferation and genome integrity. Depending on cell cycle stage, DSBs are preferentially repaired by non-homologous end joining or homologous recombination (HR). In recent years, numerous reports have revealed that DSBs enhance DNA-RNA hybrid formation around the break site. We call these hybrids "break-induced RNA-DNA hybrids" (BIRDHs) to differentiate them from sporadic R-loops consisting of DNA-RNA hybrids and a displaced single-strand DNA occurring co-transcriptionally in intact DNA. Here, we review and discuss the most relevant data about BIRDHs, with a focus on two main questions raised: (i) whether BIRDHs form by de novo transcription after a DSB or by a pre-existing nascent RNA in DNA regions undergoing transcription and (ii) whether they have a positive role in HR or are just obstacles to HR accidentally generated as an intrinsic risk of transcription. We aim to provide a comprehensive view of the exciting and yet unresolved questions about the source and impact of BIRDHs in the cell.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
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9
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Molugu K, Khajanchi N, Lazzarotto CR, Tsai SQ, Saha K. Trichostatin A for Efficient CRISPR-Cas9 Gene Editing of Human Pluripotent Stem Cells. CRISPR J 2023; 6:473-485. [PMID: 37676985 PMCID: PMC10611976 DOI: 10.1089/crispr.2023.0033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 07/31/2023] [Indexed: 09/09/2023] Open
Abstract
Genome-edited human-induced pluripotent stem cells (iPSCs) have broad applications in disease modeling, drug discovery, and regenerative medicine. Despite the development of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system, the gene editing process is inefficient and can take several weeks to months to generate edited iPSC clones. We developed a strategy to improve the efficiency of the iPSC gene editing process via application of a small-molecule, trichostatin A (TSA), a Class I and II histone deacetylase inhibitor. We observed that TSA decreased global chromatin condensation and further resulted in increased gene-editing efficiency of iPSCs by twofold to fourfold while concurrently ensuring no increased off-target effects. The edited iPSCs could be clonally expanded while maintaining genomic integrity and pluripotency. The rapid generation of therapeutically relevant gene-edited iPSCs could be enabled by these findings.
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Affiliation(s)
- Kaivalya Molugu
- Biophysics Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA; St Jude Children's Research Hospital, Memphis, Tennessee, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, Wisconsin, USA; St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Namita Khajanchi
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, Wisconsin, USA; St Jude Children's Research Hospital, Memphis, Tennessee, USA
- Department of Biomedical and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; and St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Cicera R. Lazzarotto
- Department of Hematology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Shengdar Q. Tsai
- Department of Hematology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Krishanu Saha
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, Wisconsin, USA; St Jude Children's Research Hospital, Memphis, Tennessee, USA
- Department of Biomedical and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; and St Jude Children's Research Hospital, Memphis, Tennessee, USA
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10
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Komluski J, Habig M, Stukenbrock EH. Repeat-Induced Point Mutation and Gene Conversion Coinciding with Heterochromatin Shape the Genome of a Plant-Pathogenic Fungus. mBio 2023:e0329022. [PMID: 37093087 DOI: 10.1128/mbio.03290-22] [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: 04/25/2023] Open
Abstract
Meiosis is associated with genetic changes in the genome-via recombination, gene conversion, and mutations. The occurrence of gene conversion and mutations during meiosis may further be influenced by the chromatin conformation, similar to the effect of the chromatin conformation on the mitotic mutation rate. To date, however, the exact distribution and type of meiosis-associated changes and the role of the chromatin conformation in this context are largely unexplored. Here, we determine recombination, gene conversion, and de novo mutations using whole-genome sequencing of all meiotic products of 23 individual meioses in Zymoseptoria tritici, an important pathogen of wheat. We confirm a high genome-wide recombination rate of 65 centimorgan (cM)/Mb and see higher recombination rates on the accessory compared to core chromosomes. A substantial fraction of 0.16% of all polymorphic markers was affected by gene conversions, showing a weak GC-bias and occurring at higher frequency in regions of constitutive heterochromatin, indicated by the histone modification H3K9me3. The de novo mutation rate associated with meiosis was approximately three orders of magnitude higher than the corresponding mitotic mutation rate. Importantly, repeat-induced point mutation (RIP), a fungal defense mechanism against duplicated sequences, is active in Z. tritici and responsible for the majority of these de novo meiotic mutations. Our results indicate that the genetic changes associated with meiosis are a major source of variability in the genome of an important plant pathogen and shape its evolutionary trajectory. IMPORTANCE The impact of meiosis on the genome composition via gene conversion and mutations is mostly poorly understood, in particular, for non-model species. Here, we sequenced all four meiotic products for 23 individual meioses and determined the genetic changes caused by meiosis for the important fungal wheat pathogen Zymoseptoria tritici. We found a high rate of gene conversions and an effect of the chromatin conformation on gene conversion rates. Higher conversion rates were found in regions enriched with the H3K9me3-a mark for constitutive heterochromatin. Most importantly, meiosis was associated with a much higher frequency of de novo mutations than mitosis; 78% of the meiotic mutations were caused by repeat-induced point mutations-a fungal defense mechanism against duplicated sequences. In conclusion, the genetic changes associated with meiosis are therefore a major factor shaping the genome of this fungal pathogen.
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Affiliation(s)
- Jovan Komluski
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
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11
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Wainberg ZA, Singh AS, Konecny GE, McCann KE, Hecht JR, Goldman J, Chmielowski B, Finn RS, O'Brien N, Von Euw E, Price MM, Martinez D, Yonemoto L, Brennan M, Glaspy JA, Slamon DJ. Preclinical and Clinical Trial Results Using Talazoparib and Low-Dose Chemotherapy. Clin Cancer Res 2023; 29:40-49. [PMID: 36136304 DOI: 10.1158/1078-0432.ccr-22-1553] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/25/2022] [Accepted: 09/19/2022] [Indexed: 02/06/2023]
Abstract
PURPOSE On the basis of preclinical data, we hypothesized that low doses of chemotherapy (10% of therapeutic doses) with full dose of a PARP inhibitor could have improved efficacy and tolerability. PATIENTS AND METHODS In this phase I dose-escalation study, patients with BRCA-normal advanced malignancies were assigned to either talazoparib/temozolomide or talazoparib/irinotecan. Talazoparib was dose-escalated from 500 mcg to 1 mg daily before dose escalation of temozolomide/irinotecan. The starting dose of temozolomide was 25 mg/m2/day orally on days 1 to 5 and irinotecan was 25 mg/m2/day intravenously on days 1 and 15. The primary objectives of this trial were safety and tolerability, dose-limiting toxicities (DLT), and maximum tolerated dose (MTD). RESULTS Of 40 patients enrolled, 18 (mean: 7 prior therapies) were enrolled in talazoparib + temozolomide and 22 in talazoparib + irinotecan. DLTs were hematologic in both arms, but all hematologic adverse events resolved with either treatment interruption and/or dose reductions of talazoparib. The MTDs were talazoparib 1 mg + temozolomide 37.5 mg/m2 and talazoparib 1 mg + irinotecan 37.5 mg/m2. There were four partial responses in the talazoparib + temozolomide arm and five in the talazoparib + irinotecan arm for a response rate of 23% (9/40). The pharmacokinetic profiles of talazoparib + temozolomide/irinotecan were similar to that of talazoparib monotherapy. Responses were seen independent of homologous recombination (HR) status and HR deficiency score. CONCLUSIONS These results show that talazoparib with low-dose temozolomide or irinotecan is reasonably well tolerated and demonstrates clinical activity in a wide range of cancers. Randomized trials of talazoparib with or without low-dose chemotherapy are ongoing in small cell lung cancer and ovarian cancer.
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Affiliation(s)
- Zev A Wainberg
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Arun S Singh
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Gottfried E Konecny
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Kelly E McCann
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - J Randolph Hecht
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Jonathan Goldman
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Bartosz Chmielowski
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Richard S Finn
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Neil O'Brien
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Erika Von Euw
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Megan M Price
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Diego Martinez
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Lisa Yonemoto
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Meghan Brennan
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - John A Glaspy
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
| | - Dennis J Slamon
- David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California
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12
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Awwad SW, Darawshe MM, Machour FE, Arman I, Ayoub N. Recruitment of RBM6 to DNA Double-Strand Breaks Fosters Homologous Recombination Repair. Mol Cell Biol 2023; 43:130-142. [PMID: 36941773 PMCID: PMC10038030 DOI: 10.1080/10985549.2023.2187105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 12/20/2022] [Accepted: 02/01/2023] [Indexed: 03/23/2023] Open
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that threaten genome integrity and cell survival. To avoid harmful repercussions of DSBs, a wide variety of DNA repair factors are recruited to execute DSB repair. Previously, we demonstrated that RBM6 splicing factor facilitates homologous recombination (HR) of DSB by regulating alternative splicing-coupled nonstop-decay of the HR protein APBB1/Fe65. Here, we describe a splicing-independent function of RBM6 in promoting HR repair of DSBs. We show that RBM6 is recruited to DSB sites and PARP1 activity indirectly regulates RBM6 recruitment to DNA breakage sites. Deletion mapping analysis revealed a region containing five glycine residues within the G-patch domain that regulates RBM6 accumulation at DNA damage sites. We further ascertain that RBM6 interacts with Rad51, and this interaction is attenuated in RBM6 mutant lacking the G-patch domain (RBM6del(G-patch)). Consequently, RBM6del(G-patch) cells exhibit reduced levels of Rad51 foci after ionizing radiation. In addition, while RBM6 deletion mutant lacking the G-patch domain has no detectable effect on the expression levels of its splicing targets Fe65 and Eya2, it fails to restore the integrity of HR. Altogether, our results suggest that RBM6 recruitment to DSB promotes HR repair, irrespective of its splicing activity.HIGHLIGHTSPARP1 activity indirectly regulates RBM6 recruitment to DNA damage sites.Five glycine residues within the G-patch domain of RBM6 are critical for its recruitment to DNA damage sites, but dispensable for its splicing activity.RBM6 G-patch domain fosters its interaction with Rad51 and promotes Rad51 foci formation following irradiation.RBM6 recruitment to DSB sites underpins HR repair.
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Affiliation(s)
- Samah W. Awwad
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Malak M. Darawshe
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Feras E. Machour
- Department of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Inbar Arman
- 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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13
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Min S, Ji JH, Heo Y, Cho H. Transcriptional regulation and chromatin dynamics at DNA double-strand breaks. Exp Mol Med 2022; 54:1705-1712. [PMID: 36229590 PMCID: PMC9636152 DOI: 10.1038/s12276-022-00862-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/27/2022] [Accepted: 08/01/2022] [Indexed: 12/29/2022] Open
Abstract
In eukaryotic cells, DNA damage can occur at any time and at any chromatin locus, including loci at which active transcription is taking place. DNA double-strand breaks affect chromatin integrity and elicit a DNA damage response to facilitate repair of the DNA lesion. Actively transcribed genes near DNA lesions are transiently suppressed by crosstalk between DNA damage response factors and polycomb repressive complexes. Epigenetic modulation of the chromatin environment also contributes to efficient DNA damage response signaling and transcriptional repression. On the other hand, RNA transcripts produced in the G1 phase, as well as the active chromatin context of the lesion, appear to drive homologous recombination repair. Here, we discuss how the ISWI family of chromatin remodeling factors coordinates the DNA damage response and transcriptional repression, especially in transcriptionally active regions, highlighting the direct modulation of the epigenetic environment.
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Affiliation(s)
- Sunwoo Min
- grid.251916.80000 0004 0532 3933Department of Biochemistry, Ajou University School of Medicine, Suwon, 16499 Korea ,grid.251916.80000 0004 0532 3933Genomic Instability Research Center, Ajou University School of Medicine, Suwon, 16499 Korea
| | - Jae-Hoon Ji
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, The University of Texas Health San Antonio, Texas, 78229-3000 USA
| | - Yungyeong Heo
- grid.251916.80000 0004 0532 3933Department of Biochemistry, Ajou University School of Medicine, Suwon, 16499 Korea ,grid.251916.80000 0004 0532 3933Genomic Instability Research Center, Ajou University School of Medicine, Suwon, 16499 Korea
| | - Hyeseong Cho
- grid.251916.80000 0004 0532 3933Department of Biochemistry, Ajou University School of Medicine, Suwon, 16499 Korea ,grid.251916.80000 0004 0532 3933Genomic Instability Research Center, Ajou University School of Medicine, Suwon, 16499 Korea
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14
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Saayman X, Esashi F. Breaking the paradigm: early insights from mammalian DNA breakomes. FEBS J 2022; 289:2409-2428. [PMID: 33792193 PMCID: PMC9451923 DOI: 10.1111/febs.15849] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 03/04/2021] [Accepted: 03/29/2021] [Indexed: 12/13/2022]
Abstract
DNA double-strand breaks (DSBs) can result from both exogenous and endogenous sources and are potentially toxic lesions to the human genome. If improperly repaired, DSBs can threaten genome integrity and contribute to premature ageing, neurodegenerative disorders and carcinogenesis. Through decades of work on genome stability, it has become evident that certain regions of the genome are inherently more prone to breakage than others, known as genome instability hotspots. Recent advancements in sequencing-based technologies now enable the profiling of genome-wide distributions of DSBs, also known as breakomes, to systematically map these instability hotspots. Here, we review the application of these technologies and their implications for our current understanding of the genomic regions most likely to drive genome instability. These breakomes ultimately highlight both new and established breakage hotspots including actively transcribed regions, loop boundaries and early-replicating regions of the genome. Further, these breakomes challenge the paradigm that DNA breakage primarily occurs in hard-to-replicate regions. With these advancements, we begin to gain insights into the biological mechanisms both invoking and protecting against genome instability.
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Affiliation(s)
- Xanita Saayman
- Sir William Dunn School of Pathology, University of Oxford, UK
| | - Fumiko Esashi
- Sir William Dunn School of Pathology, University of Oxford, UK
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15
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Abu-Zhayia ER, Bishara LA, Machour FE, Barisaac AS, Ben-Oz BM, Ayoub N. CDYL1-dependent decrease in lysine crotonylation at DNA double-strand break sites functionally uncouples transcriptional silencing and repair. Mol Cell 2022; 82:1940-1955.e7. [PMID: 35447080 DOI: 10.1016/j.molcel.2022.03.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 01/17/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022]
Abstract
Previously, we showed that CDYL1 is recruited to DNA double-strand breaks (DSBs) to promote homologous recombination (HR) repair and foster transcriptional silencing. However, how CDYL1 elicits DSB-induced silencing is not fully understood. Here, we identify a CDYL1-dependent local decrease in the transcriptionally active marks histone lysine crotonylation (Kcr) and crotonylated lysine 9 of H3 (H3K9cr) at AsiSI-induced DSBs, which correlates with transcriptional silencing. Mechanistically, we reveal that CDYL1 crotonyl-CoA hydratase activity counteracts Kcr and H3K9cr at DSB sites, which triggers the eviction of the transcription elongation factor ENL and fosters transcriptional silencing. Furthermore, genetic inhibition of CDYL1 hydratase activity blocks the reduction in H3K9cr and alleviates DSB-induced silencing, whereas HR efficiency unexpectedly remains intact. Therefore, our results functionally uncouple the repair and silencing activity of CDYL1 at DSBs. In a broader context, we address a long-standing question concerning the functional relationship between HR repair and DSB-induced silencing, suggesting that they may occur independently.
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Affiliation(s)
- Enas R Abu-Zhayia
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Laila A Bishara
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Feras E Machour
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Alma Sophia Barisaac
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Bella M Ben-Oz
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Nabieh Ayoub
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
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16
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Rawal CC, Butova NL, Mitra A, Chiolo I. An Expanding Toolkit for Heterochromatin Repair Studies. Genes (Basel) 2022; 13:genes13030529. [PMID: 35328082 PMCID: PMC8955653 DOI: 10.3390/genes13030529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/04/2022] Open
Abstract
Pericentromeric heterochromatin is mostly composed of repetitive DNA sequences prone to aberrant recombination. Cells have developed highly specialized mechanisms to enable ‘safe’ homologous recombination (HR) repair while preventing aberrant recombination in this domain. Understanding heterochromatin repair responses is essential to understanding the critical mechanisms responsible for genome integrity and tumor suppression. Here, we review the tools, approaches, and methods currently available to investigate double-strand break (DSB) repair in pericentromeric regions, and also suggest how technologies recently developed for euchromatin repair studies can be adapted to characterize responses in heterochromatin. With this ever-growing toolkit, we are witnessing exciting progress in our understanding of how the ‘dark matter’ of the genome is repaired, greatly improving our understanding of genome stability mechanisms.
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17
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Gómez-González B, Dutta A, Feng W. Editorial: The Role of RNA in Genome Stability: To Wreck or Repair? Front Mol Biosci 2022; 9:848217. [PMID: 35224000 PMCID: PMC8865954 DOI: 10.3389/fmolb.2022.848217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/21/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Belén Gómez-González
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC, Seville, Spain
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
- *Correspondence: Belén Gómez-González, ; Arijit Dutta, ; Wenyi Feng,
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18
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Phipps J, Dubrana K. DNA Repair in Space and Time: Safeguarding the Genome with the Cohesin Complex. Genes (Basel) 2022; 13:198. [PMID: 35205243 PMCID: PMC8872453 DOI: 10.3390/genes13020198] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 12/04/2022] Open
Abstract
DNA double-strand breaks (DSBs) are a deleterious form of DNA damage, which must be robustly addressed to ensure genome stability. Defective repair can result in chromosome loss, point mutations, loss of heterozygosity or chromosomal rearrangements, which could lead to oncogenesis or cell death. We explore the requirements for the successful repair of DNA DSBs by non-homologous end joining and homology-directed repair (HDR) mechanisms in relation to genome folding and dynamics. On the occurrence of a DSB, local and global chromatin composition and dynamics, as well as 3D genome organization and break localization within the nuclear space, influence how repair proceeds. The cohesin complex is increasingly implicated as a key regulator of the genome, influencing chromatin composition and dynamics, and crucially genome organization through folding chromosomes by an active loop extrusion mechanism, and maintaining sister chromatid cohesion. Here, we consider how this complex is now emerging as a key player in the DNA damage response, influencing repair pathway choice and efficiency.
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Affiliation(s)
| | - Karine Dubrana
- UMR Stabilité Génétique Cellules Souches et Radiations, INSERM, iRCM/IBFJ CEA, Université de Paris and Université Paris-Saclay, F-92265 Fontenay-aux-Roses, France;
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19
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Hausmann M, Hildenbrand G, Pilarczyk G. Networks and Islands of Genome Nano-architecture and Their Potential Relevance for Radiation Biology : (A Hypothesis and Experimental Verification Hints). Results Probl Cell Differ 2022; 70:3-34. [PMID: 36348103 DOI: 10.1007/978-3-031-06573-6_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The cell nucleus is a complex biological system in which simultaneous reactions and functions take place to keep the cell as an individualized, specialized system running well. The cell nucleus contains chromatin packed in various degrees of density and separated in volumes of chromosome territories and subchromosomal domains. Between the chromatin, however, there is enough "free" space for floating RNA, proteins, enzymes, ATPs, ions, water molecules, etc. which are trafficking by super- and supra-diffusion to the interaction points where they are required. It seems that this trafficking works somehow automatically and drives the system perfectly. After exposure to ionizing radiation causing DNA damage from single base damage up to chromatin double-strand breaks, the whole system "cell nucleus" responds, and repair processes are starting to recover the fully functional and intact system. In molecular biology, many individual epigenetic pathways of DNA damage response or repair of single and double-strand breaks are described. How these responses are embedded into the response of the system as a whole is often out of the focus of consideration. In this article, we want to follow the hypothesis of chromatin architecture's impact on epigenetic pathways and vice versa. Based on the assumption that chromatin acts like an "aperiodic solid state within a limited volume," functionally determined networks and local topologies ("islands") can be defined that drive the appropriate repair process at a given damage site. Experimental results of investigations of the chromatin nano-architecture and DNA repair clusters obtained by means of single-molecule localization microscopy offer hints and perspectives that may contribute to verifying the hypothesis.
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Affiliation(s)
- Michael Hausmann
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany.
| | - Georg Hildenbrand
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
| | - Götz Pilarczyk
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
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20
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Lou J, Solano A, Liang Z, Hinde E. Phasor Histone FLIM-FRET Microscopy Maps Nuclear-Wide Nanoscale Chromatin Architecture With Respect to Genetically Induced DNA Double-Strand Breaks. Front Genet 2021; 12:770081. [PMID: 34956323 PMCID: PMC8702996 DOI: 10.3389/fgene.2021.770081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/10/2021] [Indexed: 12/30/2022] Open
Abstract
A DNA double-strand break (DSB) takes place in the context of chromatin, and there is increasing evidence for chromatin structure to play a functional role in DSB signaling and repair. Thus, there is an emerging need for quantitative microscopy methods that can directly measure chromatin network architecture and detect changes in this structural framework upon DSB induction within an intact nucleus. To address this demand, here we present the phasor approach to fluorescence lifetime imaging microscopy (FLIM) of Förster resonance energy transfer (FRET) between fluorescently labeled histones in the DSB inducible via AsiSI cell system (DIvA), which has sufficient spatial resolution to map nuclear-wide chromatin compaction at the level of nucleosome proximity with respect to multiple site-specific DSBs. We also demonstrate that when phasor histone FLIM-FRET is coupled with immunofluorescence, this technology has the unique advantage of enabling exploration of any heterogeneity that exists in chromatin structure at the spatially distinct and genetically induced DSBs.
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Affiliation(s)
- Jieqiong Lou
- School of Physics, University of Melbourne, Melbourne, VIC, Australia.,Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
| | - Ashleigh Solano
- School of Physics, University of Melbourne, Melbourne, VIC, Australia.,Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
| | - Zhen Liang
- Cancer and RNA Laboratory, St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia.,Department of Medicine, Melbourne Medical School, St Vincent's Hospital, University of Melbourne, Fitzroy, VIC, Australia
| | - Elizabeth Hinde
- School of Physics, University of Melbourne, Melbourne, VIC, Australia.,Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
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21
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3D Genome Organization: Causes and Consequences for DNA Damage and Repair. Genes (Basel) 2021; 13:genes13010007. [PMID: 35052348 PMCID: PMC8775012 DOI: 10.3390/genes13010007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/16/2021] [Accepted: 12/18/2021] [Indexed: 01/02/2023] Open
Abstract
The inability to repair damaged DNA severely compromises the integrity of any organism. In eukaryotes, the DNA damage response (DDR) operates within chromatin, a tightly organized DNA–histone complex in a non-random manner within the nucleus. Chromatin thus orchestrates various cellular processes, including repair. Here, we examine the chromatin landscape before, during, and after the DNA damage, focusing on double strand breaks (DSBs). We study how chromatin is modified during the repair process, not only around the damaged region (in cis), but also genome-wide (in trans). Recent evidence has highlighted a complex landscape in which different chromatin parameters (stiffness, compaction, loops) are transiently modified, defining “codes” for each specific stage of the DDR. We illustrate a novel aspect of DDR where chromatin modifications contribute to the movement of DSB-damaged chromatin, as well as undamaged chromatin, ensuring the mobilization of DSBs, their clustering, and their repair processes.
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22
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Min S, Lee HS, Ji JH, Heo Y, Kim Y, Chae S, Choi YW, Kang HC, Nakanishi M, Cho H. The chromatin remodeler RSF1 coordinates epigenetic marks for transcriptional repression and DSB repair. Nucleic Acids Res 2021; 49:12268-12283. [PMID: 34850117 PMCID: PMC8643642 DOI: 10.1093/nar/gkab1093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 02/06/2023] Open
Abstract
DNA lesions impact on local transcription and the damage-induced transcriptional repression facilitates efficient DNA repair. However, how chromatin dynamics cooperates with these two events remained largely unknown. We here show that histone H2A acetylation at K118 is enriched in transcriptionally active regions. Under DNA damage, the RSF1 chromatin remodeling factor recruits HDAC1 to DSB sites. The RSF1-HDAC1 complex induces the deacetylation of H2A(X)-K118 and its deacetylation is indispensable for the ubiquitination of histone H2A at K119. Accordingly, the acetylation mimetic H2A-K118Q suppressed the H2A-K119ub level, perturbing the transcriptional repression at DNA lesions. Intriguingly, deacetylation of H2AX at K118 also licenses the propagation of γH2AX and recruitment of MDC1. Consequently, the H2AX-K118Q limits DNA repair. Together, the RSF1-HDAC1 complex controls the traffic of the DNA damage response and transcription simultaneously in transcriptionally active chromatins. The interplay between chromatin remodelers and histone modifiers highlights the importance of chromatin versatility in the maintenance of genome integrity.
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Affiliation(s)
- Sunwoo Min
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Korea.,Genomic Instability Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Ho-Soo Lee
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Korea.,Genomic Instability Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Jae-Hoon Ji
- Genomic Instability Research Center, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Biochemistry and Structural Biology, The University of Texas Health San Antonio, TX 78229-3000, USA
| | - Yungyeong Heo
- Department of Biomedical Sciences, the Graduate School of Ajou University, Suwon, Korea
| | - Yonghyeon Kim
- Department of Biomedical Sciences, the Graduate School of Ajou University, Suwon, Korea
| | - Sunyoung Chae
- Institute of Medical Science, Ajou University School of Medicine, Suwon 16499, Korea
| | - Yong Won Choi
- Department of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - Ho-Chul Kang
- Department of Physiology, Ajou University School of Medicine, Suwon, Korea
| | - Makoto Nakanishi
- Division of Cancer Cell Biology, The University of Tokyo, Tokyo 108-8639, Japan
| | - Hyeseong Cho
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Korea.,Genomic Instability Research Center, Ajou University School of Medicine, Suwon 16499, Korea
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23
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Topological Analysis of γH2AX and MRE11 Clusters Detected by Localization Microscopy during X-ray-Induced DNA Double-Strand Break Repair. Cancers (Basel) 2021; 13:cancers13215561. [PMID: 34771723 PMCID: PMC8582740 DOI: 10.3390/cancers13215561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/30/2022] Open
Abstract
DNA double-strand breaks (DSBs), known as the most severe damage in chromatin, were induced in breast cancer cells and normal skin fibroblasts by 2 Gy ionizing photon radiation. In response to DSB induction, phosphorylation of the histone variant H2AX to γH2AX was observed in the form of foci visualized by specific antibodies. By means of super-resolution single-molecule localization microscopy (SMLM), it has been recently shown in a first article about these data that these foci can be separated into clusters of about the same size (diameter ~400 nm). The number of clusters increased with the dose applied and decreased with the repair time. It has also been shown that during the repair period, antibody-labeled MRE11 clusters of about half of the γH2AX cluster diameter were formed inside several γH2AX clusters. MRE11 is part of the MRE11-RAD50-NBS1 (MRN) complex, which is known as a DNA strand resection and broken-end bridging component in homologous recombination repair (HRR) and alternative non-homologous end joining (a-NHEJ). This article is a follow-up of the former ones applying novel procedures of mathematics (topology) and similarity measurements on the data set: to obtain a measure for cluster shape and shape similarities, topological quantifications employing persistent homology were calculated and compared. In addition, based on our findings that γH2AX clusters associated with heterochromatin show a high degree of similarity independently of dose and repair time, these earlier published topological analyses and similarity calculations comparing repair foci within individual cells were extended by topological data averaging (2nd-generation heatmaps) over all cells analyzed at a given repair time point; thereby, the two dimensions (0 and 1) expressed by components and holes were studied separately. Finally, these mean value heatmaps were averaged, in addition. For γH2AX clusters, in both normal fibroblast and MCF-7 cancer cell lines, an increased similarity was found at early time points (up to 60 min) after irradiation for both components and holes of clusters. In contrast, for MRE11, the peak in similarity was found at later time points (2 h up to 48 h) after irradiation. In general, the normal fibroblasts showed quicker phosphorylation of H2AX and recruitment of MRE11 to γH2AX clusters compared to breast cancer cells and a shorter time interval of increased similarity for γH2AX clusters. γH2AX foci and randomly distributed MRE11 molecules naturally occurring in non-irradiated control cells did not show any significant topological similarity.
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Epithelial cell transforming factor ECT2 is an important regulator of DNA double-strand break repair and genome stability. J Biol Chem 2021; 297:101036. [PMID: 34343566 PMCID: PMC8385449 DOI: 10.1016/j.jbc.2021.101036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 12/02/2022] Open
Abstract
Proteins containing breast cancer type 1 (BRCA1) C-terminal domains play crucial roles in response to and repair of DNA damage. Epithelial cell transforming factor (epithelial cell transforming sequence 2 [ECT2]) is a member of the BRCA1 C-terminal protein family, but it is not known if ECT2 directly contributes to DNA repair. In this study, we report that ECT2 is recruited to DNA lesions in a poly (ADP-ribose) polymerase 1–dependent manner. Using co-immunoprecipitation analysis, we showed that ECT2 physically associates with KU70–KU80 and BRCA1, proteins involved in nonhomologous end joining and homologous recombination, respectively. ECT2 deficiency impairs the recruitment of KU70 and BRCA1 to DNA damage sites, resulting in defective DNA double-strand break repair, an accumulation of damaged DNA, and hypersensitivity of cells to genotoxic insults. Interestingly, we demonstrated that ECT2 promotes DNA repair and genome integrity largely independently of its canonical guanine nucleotide exchange activity. Together, these results suggest that ECT2 is directly involved in DNA double-strand break repair and is an important genome caretaker.
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Ortega P, Mérida-Cerro JA, Rondón AG, Gómez-González B, Aguilera A. DNA-RNA hybrids at DSBs interfere with repair by homologous recombination. eLife 2021; 10:e69881. [PMID: 34236317 PMCID: PMC8289408 DOI: 10.7554/elife.69881] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/07/2021] [Indexed: 12/19/2022] Open
Abstract
DNA double-strand breaks (DSBs) are the most harmful DNA lesions and their repair is crucial for cell viability and genome integrity. The readout of DSB repair may depend on whether DSBs occur at transcribed versus non-transcribed regions. Some studies have postulated that DNA-RNA hybrids form at DSBs to promote recombinational repair, but others have challenged this notion. To directly assess whether hybrids formed at DSBs promote or interfere with the recombinational repair, we have used plasmid and chromosomal-based systems for the analysis of DSB-induced recombination in Saccharomyces cerevisiae. We show that, as expected, DNA-RNA hybrid formation is stimulated at DSBs. In addition, mutations that promote DNA-RNA hybrid accumulation, such as hpr1∆ and rnh1∆ rnh201∆, cause high levels of plasmid loss when DNA breaks are induced at sites that are transcribed. Importantly, we show that high levels or unresolved DNA-RNA hybrids at the breaks interfere with their repair by homologous recombination. This interference is observed for both plasmid and chromosomal recombination and is independent of whether the DSB is generated by endonucleolytic cleavage or by DNA replication. These data support a model in which DNA-RNA hybrids form fortuitously at DNA breaks during transcription and need to be removed to allow recombinational repair, rather than playing a positive role.
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Affiliation(s)
- Pedro Ortega
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de OlavideSevilleSpain
| | - José Antonio Mérida-Cerro
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de OlavideSevilleSpain
| | - Ana G Rondón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de OlavideSevilleSpain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de OlavideSevilleSpain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de OlavideSevilleSpain
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Li H, Zimmerman SE, Weyemi U. Genomic instability and metabolism in cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 364:241-265. [PMID: 34507785 DOI: 10.1016/bs.ircmb.2021.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Genomic instability and metabolic reprogramming are among the key hallmarks discriminating cancer cells from normal cells. The two phenomena contribute to the robust and evasive nature of cancer, particularly when cancer cells are exposed to chemotherapeutic agents. Genomic instability is defined as the increased frequency of mutations within the genome, while metabolic reprogramming is the alteration of metabolic pathways that cancer cells undergo to adapt to increased bioenergetic demand. An underlying source of these mutations is the aggregate product of damage to the DNA, and a defective repair pathway, both resulting in the expansion of genomic lesions prior to uncontrolled proliferation and survival of cancer cells. Exploitation of DNA damage and the subsequent DNA damage response (DDR) have aided in defining therapeutic approaches in cancer. Studies have demonstrated that targeting metabolic reprograming yields increased sensitivity to chemo- and radiotherapies. In the past decade, it has been shown that these two key features are interrelated. Metabolism impacts DNA damage and DDR via regulation of metabolite pools. Conversely, DDR affects the response of metabolic pathways to therapeutic agents. Because of the interplay between genomic instability and metabolic reprogramming, we have compiled findings which more selectively highlight the dialog between metabolism and DDR, with a particular focus on glucose metabolism and double-strand break (DSB) repair pathways. Decoding this dialog will provide significant clues for developing combination cancer therapies.
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Affiliation(s)
- Haojian Li
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Susan E Zimmerman
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Urbain Weyemi
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States.
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Analysis of chromatid-break-repair detects a homologous recombination to non-homologous end-joining switch with increasing load of DNA double-strand breaks. Mutat Res 2021; 867:503372. [PMID: 34266628 DOI: 10.1016/j.mrgentox.2021.503372] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022]
Abstract
We recently reported that when low doses of ionizing radiation induce low numbers of DNA double-strand breaks (DSBs) in G2-phase cells, about 50 % of them are repaired by homologous recombination (HR) and the remaining by classical non-homologous end-joining (c-NHEJ). However, with increasing DSB-load, the contribution of HR drops to undetectable (at ∼10 Gy) as c-NHEJ dominates. It remains unknown whether the approximately equal shunting of DSBs between HR and c-NHEJ at low radiation doses and the predominant shunting to c-NHEJ at high doses, applies to every DSB, or whether the individual characteristics of each DSB generate processing preferences. When G2-phase cells are irradiated, only about 10 % of the induced DSBs break the chromatids. This breakage allows analysis of the processing of this specific subset of DSBs using cytogenetic methods. Notably, at low radiation doses, these DSBs are almost exclusively processed by HR, suggesting that chromatin characteristics awaiting characterization underpin chromatid breakage and determine the preferential engagement of HR. Strikingly, we also discovered that with increasing radiation dose, a pathway switch to c-NHEJ occurs in the processing of this subset of DSBs. Here, we confirm and substantially extend our initial observations using additional methodologies. Wild-type cells, as well as HR and c-NHEJ mutants, are exposed to a broad spectrum of radiation doses and their response analyzed specifically in G2 phase. Our results further consolidate the observation that at doses <2 Gy, HR is the main option in the processing of the subset of DSBs generating chromatid breaks and that a pathway switch at doses between 4-6 Gy allows the progressive engagement of c-NHEJ. PARP1 inhibition, irrespective of radiation dose, leaves chromatid break repair unaffected suggesting that the contribution of alternative end-joining is undetectable under these experimental conditions.
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Averbek S, Jakob B, Durante M, Averbeck NB. O-GlcNAcylation Affects the Pathway Choice of DNA Double-Strand Break Repair. Int J Mol Sci 2021; 22:ijms22115715. [PMID: 34071949 PMCID: PMC8198441 DOI: 10.3390/ijms22115715] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/13/2022] Open
Abstract
Exposing cells to DNA damaging agents, such as ionizing radiation (IR) or cytotoxic chemicals, can cause DNA double-strand breaks (DSBs), which are crucial to repair to maintain genetic integrity. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a post-translational modification (PTM), which has been reported to be involved in the DNA damage response (DDR) and chromatin remodeling. Here, we investigated the impact of O-GlcNAcylation on the DDR, DSB repair and chromatin status in more detail. We also applied charged particle irradiation to analyze differences of O-GlcNAcylation and its impact on DSB repair in respect of spatial dose deposition and radiation quality. Various techniques were used, such as the γH2AX foci assay, live cell microscopy and Fluorescence Lifetime Microscopy (FLIM) to detect DSB rejoining, protein accumulation and chromatin states after treating the cells with O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA) inhibitors. We confirmed that O-GlcNAcylation of MDC1 is increased upon irradiation and identified additional repair factors related to Homologous Recombination (HR), CtIP and BRCA1, which were increasingly O-GlcNAcyated upon irradiation. This is consistent with our findings that the function of HR is affected by OGT inhibition. Besides, we found that OGT and OGA activity modulate chromatin compaction states, providing a potential additional level of DNA-repair regulation.
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Affiliation(s)
- Sera Averbek
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Burkhard Jakob
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
| | - Marco Durante
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Department of Physics, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Nicole B. Averbeck
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Correspondence:
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Cornelia de Lange syndrome-associated mutations cause a DNA damage signalling and repair defect. Nat Commun 2021; 12:3127. [PMID: 34035299 PMCID: PMC8149872 DOI: 10.1038/s41467-021-23500-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 04/29/2021] [Indexed: 02/07/2023] Open
Abstract
Cornelia de Lange syndrome is a multisystem developmental disorder typically caused by mutations in the gene encoding the cohesin loader NIPBL. The associated phenotype is generally assumed to be the consequence of aberrant transcriptional regulation. Recently, we identified a missense mutation in BRD4 associated with a Cornelia de Lange-like syndrome that reduces BRD4 binding to acetylated histones. Here we show that, although this mutation reduces BRD4-occupancy at enhancers it does not affect transcription of the pluripotency network in mouse embryonic stem cells. Rather, it delays the cell cycle, increases DNA damage signalling, and perturbs regulation of DNA repair in mutant cells. This uncovers a role for BRD4 in DNA repair pathway choice. Furthermore, we find evidence of a similar increase in DNA damage signalling in cells derived from NIPBL-deficient individuals, suggesting that defective DNA damage signalling and repair is also a feature of typical Cornelia de Lange syndrome. Cornelia de Lange syndrome is a developmental disorder typically caused by mutations in the gene encoding the cohesin loader NIPBL. The authors, here, by analysing previously identified mutations in BRD4 associated with the disease, reveal that a BRD4 mutation affects DNA damage signalling, and perturbs regulation of DNA repair in mutant cells.
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Schep R, Brinkman EK, Leemans C, Vergara X, van der Weide RH, Morris B, van Schaik T, Manzo SG, Peric-Hupkes D, van den Berg J, Beijersbergen RL, Medema RH, van Steensel B. Impact of chromatin context on Cas9-induced DNA double-strand break repair pathway balance. Mol Cell 2021; 81:2216-2230.e10. [PMID: 33848455 PMCID: PMC8153251 DOI: 10.1016/j.molcel.2021.03.032] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/23/2020] [Accepted: 03/19/2021] [Indexed: 01/01/2023]
Abstract
DNA double-strand break (DSB) repair is mediated by multiple pathways. It is thought that the local chromatin context affects the pathway choice, but the underlying principles are poorly understood. Using a multiplexed reporter assay in combination with Cas9 cutting, we systematically measure the relative activities of three DSB repair pathways as a function of chromatin context in >1,000 genomic locations. This reveals that non-homologous end-joining (NHEJ) is broadly biased toward euchromatin, while the contribution of microhomology-mediated end-joining (MMEJ) is higher in specific heterochromatin contexts. In H3K27me3-marked heterochromatin, inhibition of the H3K27 methyltransferase EZH2 reverts the balance toward NHEJ. Single-stranded template repair (SSTR), often used for precise CRISPR editing, competes with MMEJ and is moderately linked to chromatin context. These results provide insight into the impact of chromatin on DSB repair pathway balance and guidance for the design of Cas9-mediated genome editing experiments.
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Affiliation(s)
- Ruben Schep
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Eva K Brinkman
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Christ Leemans
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Xabier Vergara
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Cell Biology, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Robin H van der Weide
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Ben Morris
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Robotics Screening Center, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Tom van Schaik
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Stefano G Manzo
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Daniel Peric-Hupkes
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Jeroen van den Berg
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Cell Biology, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Robotics Screening Center, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - René H Medema
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Cell Biology, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands
| | - Bas van Steensel
- Oncode Institute, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, the Netherlands; Department of Cell Biology, Erasmus University Medical Centre, 3015 CN, Rotterdam, the Netherlands.
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Gómez-González B, Sessa G, Carreira A, Aguilera A. A new interaction between BRCA2 and DDX5 promotes the repair of DNA breaks at transcribed chromatin. Mol Cell Oncol 2021; 8:1910474. [PMID: 34027046 DOI: 10.1080/23723556.2021.1910474] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In a recent report, we have revealed a new interaction between the BRCA2 DNA repair associated protein (BRCA2) and the DEAD-box helicase 5 (DDX5) at DNA breaks that promotes unwinding DNA-RNA hybrids within transcribed chromatin and favors repair. Interestingly, BRCA2-DDX5 interaction is impaired in cells expressing the BRCA2T2 07A missense variant found in breast cancer patients.
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Affiliation(s)
- Belen Gómez-González
- Centro Andaluz De Biología Molecular Y Medicina Regenerativa (CABIMER), Universidad De Sevilla-CSIC, Seville, Spain.,Departamento De Genética, Facultad De Biología, University of Seville, Seville, Spain
| | - Gaetana Sessa
- Cnrs UMR3348, Institut Curie, Université PSL, Orsay, France.,Cnrs UMR3348, Université Paris-Saclay, Orsay, France
| | - Aura Carreira
- Cnrs UMR3348, Institut Curie, Université PSL, Orsay, France.,Cnrs UMR3348, Université Paris-Saclay, Orsay, France
| | - Andrés Aguilera
- Centro Andaluz De Biología Molecular Y Medicina Regenerativa (CABIMER), Universidad De Sevilla-CSIC, Seville, Spain.,Departamento De Genética, Facultad De Biología, University of Seville, Seville, Spain
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Hausmann M, Falk M, Neitzel C, Hofmann A, Biswas A, Gier T, Falkova I, Heermann DW, Hildenbrand G. Elucidation of the Clustered Nano-Architecture of Radiation-Induced DNA Damage Sites and Surrounding Chromatin in Cancer Cells: A Single Molecule Localization Microscopy Approach. Int J Mol Sci 2021; 22:3636. [PMID: 33807337 PMCID: PMC8037797 DOI: 10.3390/ijms22073636] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/20/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
In cancer therapy, the application of (fractionated) harsh radiation treatment is state of the art for many types of tumors. However, ionizing radiation is a "double-edged sword"-it can kill the tumor but can also promote the selection of radioresistant tumor cell clones or even initiate carcinogenesis in the normal irradiated tissue. Individualized radiotherapy would reduce these risks and boost the treatment, but its development requires a deep understanding of DNA damage and repair processes and the corresponding control mechanisms. DNA double strand breaks (DSBs) and their repair play a critical role in the cellular response to radiation. In previous years, it has become apparent that, beyond genetic and epigenetic determinants, the structural aspects of damaged chromatin (i.e., not only of DSBs themselves but also of the whole damage-surrounding chromatin domains) form another layer of complex DSB regulation. In the present article, we summarize the application of super-resolution single molecule localization microscopy (SMLM) for investigations of these structural aspects with emphasis on the relationship between the nano-architecture of radiation-induced repair foci (IRIFs), represented here by γH2AX foci, and their chromatin environment. Using irradiated HeLa cell cultures as an example, we show repair-dependent rearrangements of damaged chromatin and analyze the architecture of γH2AX repair clusters according to topological similarities. Although HeLa cells are known to have highly aberrant genomes, the topological similarity of γH2AX was high, indicating a functional, presumptively genome type-independent relevance of structural aspects in DSB repair. Remarkably, nano-scaled chromatin rearrangements during repair depended both on the chromatin domain type and the treatment. Based on these results, we demonstrate how the nano-architecture and topology of IRIFs and chromatin can be determined, point to the methodological relevance of SMLM, and discuss the consequences of the observed phenomena for the DSB repair network regulation or, for instance, radiation treatment outcomes.
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Affiliation(s)
- Michael Hausmann
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (C.N.); (A.B.); (T.G.); (G.H.)
| | - Martin Falk
- Institute of Biophysics, Czech Academy of Sciences, 612 65 Brno, Czech Republic;
| | - Charlotte Neitzel
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (C.N.); (A.B.); (T.G.); (G.H.)
| | - Andreas Hofmann
- Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany; (A.H.); (D.W.H.)
| | - Abin Biswas
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (C.N.); (A.B.); (T.G.); (G.H.)
| | - Theresa Gier
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (C.N.); (A.B.); (T.G.); (G.H.)
| | - Iva Falkova
- Institute of Biophysics, Czech Academy of Sciences, 612 65 Brno, Czech Republic;
| | - Dieter W. Heermann
- Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany; (A.H.); (D.W.H.)
| | - Georg Hildenbrand
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (C.N.); (A.B.); (T.G.); (G.H.)
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Yasuda T, Takizawa K, Ui A, Hama M, Kagawa W, Sugasawa K, Tajima K. Human SIRT2 and SIRT3 deacetylases function in DNA homologous recombinational repair. Genes Cells 2021; 26:328-335. [PMID: 33624391 DOI: 10.1111/gtc.12842] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 02/04/2021] [Accepted: 02/19/2021] [Indexed: 12/14/2022]
Abstract
SIRT2 and SIRT3 protein deacetylases maintain genome integrity and stability. However, their mechanisms for maintaining the genome remain unclear. To examine the roles of SIRT2 and SIRT3 in DSB repair, I-SceI-based GFP reporter assays for HR, single-strand annealing (SSA) and nonhomologous end joining (NHEJ) repair were performed under SIRT2- or SIRT3-depleted conditions. SIRT2 or SIRT3 depletion inhibited HR repair equally to RAD52 depletion, but did not affect SSA and NHEJ repairs. SIRT2 or SIRT3 depletion disturbed the recruitment of RAD51 to DSB sites, an essential step for RAD51-dependent HR repair, but not directly through RAD52 deacetylation. SIRT2 or SIRT3 depletion decreased the colocalization of γH2AX foci with RPA1, and thus, they might be involved in initiating DSB end resection for the recruitment of RAD51 to DSB sites at an early step in HR repair. These results show the novel underlying mechanism of the SIRT2 and SIRT3 functions in HR for genome stability.
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Affiliation(s)
- Takeshi Yasuda
- National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Sciences and Technology (QST), Chiba, Japan
| | - Kazuya Takizawa
- National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Sciences and Technology (QST), Chiba, Japan
| | - Ayako Ui
- Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.,Division of Dynamic Proteome in Cancer and Aging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Michio Hama
- National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Sciences and Technology (QST), Chiba, Japan
| | - Wataru Kagawa
- Program in Chemistry and Life Science, Department of Interdisciplinary Science and Engineering, School of Science and Engineering, Meisei University, Hino, Japan
| | - Kaoru Sugasawa
- Biosignal Research Center, and Graduate School of Science, Kobe University, Kobe, Japan
| | - Katsushi Tajima
- National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Sciences and Technology (QST), Chiba, Japan
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35
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Falk M, Hausmann M. A Paradigm Revolution or Just Better Resolution-Will Newly Emerging Superresolution Techniques Identify Chromatin Architecture as a Key Factor in Radiation-Induced DNA Damage and Repair Regulation? Cancers (Basel) 2020; 13:E18. [PMID: 33374540 PMCID: PMC7793109 DOI: 10.3390/cancers13010018] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 12/18/2020] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) have been recognized as the most serious lesions in irradiated cells. While several biochemical pathways capable of repairing these lesions have been identified, the mechanisms by which cells select a specific pathway for activation at a given DSB site remain poorly understood. Our knowledge of DSB induction and repair has increased dramatically since the discovery of ionizing radiation-induced foci (IRIFs), initiating the possibility of spatiotemporally monitoring the assembly and disassembly of repair complexes in single cells. IRIF exploration revealed that all post-irradiation processes-DSB formation, repair and misrepair-are strongly dependent on the characteristics of DSB damage and the microarchitecture of the whole affected chromatin domain in addition to the cell status. The microscale features of IRIFs, such as their morphology, mobility, spatiotemporal distribution, and persistence kinetics, have been linked to repair mechanisms. However, the influence of various biochemical and structural factors and their specific combinations on IRIF architecture remains unknown, as does the hierarchy of these factors in the decision-making process for a particular repair mechanism at each individual DSB site. New insights into the relationship between the physical properties of the incident radiation, chromatin architecture, IRIF architecture, and DSB repair mechanisms and repair efficiency are expected from recent developments in optical superresolution microscopy (nanoscopy) techniques that have shifted our ability to analyze chromatin and IRIF architectures towards the nanoscale. In the present review, we discuss this relationship, attempt to correlate still rather isolated nanoscale studies with already better-understood aspects of DSB repair at the microscale, and consider whether newly emerging "correlated multiscale structuromics" can revolutionarily enhance our knowledge in this field.
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Affiliation(s)
- Martin Falk
- Institute of Biophysics, The Czech Academy of Sciences, 612 65 Brno, Czech Republic
| | - Michael Hausmann
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany;
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Korsholm LM, Gál Z, Nieto B, Quevedo O, Boukoura S, Lund CC, Larsen DH. Recent advances in the nucleolar responses to DNA double-strand breaks. Nucleic Acids Res 2020; 48:9449-9461. [PMID: 32857853 PMCID: PMC7515731 DOI: 10.1093/nar/gkaa713] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/13/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
DNA damage poses a serious threat to human health and cells therefore continuously monitor and repair DNA lesions across the genome. Ribosomal DNA is a genomic domain that represents a particular challenge due to repetitive sequences, high transcriptional activity and its localization in the nucleolus, where the accessibility of DNA repair factors is limited. Recent discoveries have significantly extended our understanding of how cells respond to DNA double-strand breaks (DSBs) in the nucleolus, and new kinases and multiple down-stream targets have been identified. Restructuring of the nucleolus can occur as a consequence of DSBs and new data point to an active regulation of this process, challenging previous views. Furthermore, new insights into coordination of cell cycle phases and ribosomal DNA repair argue against existing concepts. In addition, the importance of nucleolar-DNA damage response (n-DDR) mechanisms for maintenance of genome stability and the potential of such factors as anti-cancer targets is becoming apparent. This review will provide a detailed discussion of recent findings and their implications for our understanding of the n-DDR. The n-DDR shares features with the DNA damage response (DDR) elsewhere in the genome but is also emerging as an independent response unique to ribosomal DNA and the nucleolus.
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Affiliation(s)
| | | | - Blanca Nieto
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Oliver Quevedo
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Stavroula Boukoura
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Casper Carstens Lund
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
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Wengner AM, Scholz A, Haendler B. Targeting DNA Damage Response in Prostate and Breast Cancer. Int J Mol Sci 2020; 21:E8273. [PMID: 33158305 PMCID: PMC7663807 DOI: 10.3390/ijms21218273] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 02/06/2023] Open
Abstract
Steroid hormone signaling induces vast gene expression programs which necessitate the local formation of transcription factories at regulatory regions and large-scale alterations of the genome architecture to allow communication among distantly related cis-acting regions. This involves major stress at the genomic DNA level. Transcriptionally active regions are generally instable and prone to breakage due to the torsional stress and local depletion of nucleosomes that make DNA more accessible to damaging agents. A dedicated DNA damage response (DDR) is therefore essential to maintain genome integrity at these exposed regions. The DDR is a complex network involving DNA damage sensor proteins, such as the poly(ADP-ribose) polymerase 1 (PARP-1), the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), the ataxia-telangiectasia-mutated (ATM) kinase and the ATM and Rad3-related (ATR) kinase, as central regulators. The tight interplay between the DDR and steroid hormone receptors has been unraveled recently. Several DNA repair factors interact with the androgen and estrogen receptors and support their transcriptional functions. Conversely, both receptors directly control the expression of agents involved in the DDR. Impaired DDR is also exploited by tumors to acquire advantageous mutations. Cancer cells often harbor germline or somatic alterations in DDR genes, and their association with disease outcome and treatment response led to intensive efforts towards identifying selective inhibitors targeting the major players in this process. The PARP-1 inhibitors are now approved for ovarian, breast, and prostate cancer with specific genomic alterations. Additional DDR-targeting agents are being evaluated in clinical studies either as single agents or in combination with treatments eliciting DNA damage (e.g., radiation therapy, including targeted radiotherapy, and chemotherapy) or addressing targets involved in maintenance of genome integrity. Recent preclinical and clinical findings made in addressing DNA repair dysfunction in hormone-dependent and -independent prostate and breast tumors are presented. Importantly, the combination of anti-hormonal therapy with DDR inhibition or with radiation has the potential to enhance efficacy but still needs further investigation.
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Affiliation(s)
| | | | - Bernard Haendler
- Preclinical Research, Research & Development, Pharmaceuticals, Bayer AG, Müllerstr. 178, 13353 Berlin, Germany; (A.M.W.); (A.S.)
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38
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Analyzing Homologous Recombination at a Genome-Wide Level. Methods Mol Biol 2020. [PMID: 32840796 DOI: 10.1007/978-1-0716-0644-5_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Among the types of damage, DNA double-strand breaks (DSBs) (provoked by various environmental stresses, but also during normal cell metabolic activity) are the most deleterious, as illustrated by the variety of human diseases associated with DSB repair defects. DSBs are repaired by two groups of pathways: homologous recombination (HR) and nonhomologous end joining. These pathways do not trigger the same mutational signatures, and multiple factors, such as cell cycle stage, the complexity of the lesion and also the genomic location, contribute to the choice between these repair pathways. To study the usage of the HR machinery at DSBs, we propose a genome-wide method based on the chromatin immunoprecipitation of the HR core component Rad51, followed by high-throughput sequencing.
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Fages J, Chailleux C, Humbert J, Jang SM, Loehr J, Lambert JP, Côté J, Trouche D, Canitrot Y. JMJD6 participates in the maintenance of ribosomal DNA integrity in response to DNA damage. PLoS Genet 2020; 16:e1008511. [PMID: 32598339 PMCID: PMC7351224 DOI: 10.1371/journal.pgen.1008511] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 07/10/2020] [Accepted: 05/05/2020] [Indexed: 01/08/2023] Open
Abstract
Ribosomal DNA (rDNA) is the most transcribed genomic region and contains hundreds of tandem repeats. Maintaining these rDNA repeats as well as the level of rDNA transcription is essential for cellular homeostasis. DNA damages generated in rDNA need to be efficiently and accurately repaired and rDNA repeats instability has been reported in cancer, aging and neurological diseases. Here, we describe that the histone demethylase JMJD6 is rapidly recruited to nucleolar DNA damage and is crucial for the relocalisation of rDNA in nucleolar caps. Yet, JMJD6 is dispensable for rDNA transcription inhibition. Mass spectrometry analysis revealed that JMJD6 interacts with the nucleolar protein Treacle and modulates its interaction with NBS1. Moreover, cells deficient for JMJD6 show increased sensitivity to nucleolar DNA damage as well as loss and rearrangements of rDNA repeats upon irradiation. Altogether our data reveal that rDNA transcription inhibition is uncoupled from rDNA relocalisation into nucleolar caps and that JMJD6 is required for rDNA stability through its role in nucleolar caps formation. Ribosomal DNA is composed of repeated sequences and is the most transcribed genomic region. Transcription of rDNA is essential for cellular homeostasis and cell proliferation. Numerous pathologies such as cancer and neurological disorders are associated with defective rDNA repeats maintenance. The mechanisms involved in the control of rDNA integrity involve major DNA repair pathways such as Non-Homologous End Joining and Homologous Recombination. However, how they are controlled and orchestrated is poorly understood. Here, we identified JMJD6 as a new member of the maintenance of rDNA integrity. We observed that JMJD6 controls the recruitment of NBS1 in the nucleolus in order to lead to the proper management of rDNA damages
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Affiliation(s)
- Jérémie Fages
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Catherine Chailleux
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Jonathan Humbert
- Centre de Recherche sur le Cancer de l'Université Laval, axe Oncologie du Centre de recherche du CHU de Québec-Université Laval, Québec, Canada
| | - Suk-Min Jang
- Centre de Recherche sur le Cancer de l'Université Laval, axe Oncologie du Centre de recherche du CHU de Québec-Université Laval, Québec, Canada
| | - Jérémy Loehr
- Centre de Recherche sur le Cancer de l'Université Laval, axe Endocrinologie et néphrologie du Centre de recherche du CHU de Québec-Université Laval, Québec, Canada
| | - Jean-Philippe Lambert
- Centre de Recherche sur le Cancer de l'Université Laval, axe Endocrinologie et néphrologie du Centre de recherche du CHU de Québec-Université Laval, Québec, Canada
| | - Jacques Côté
- Centre de Recherche sur le Cancer de l'Université Laval, axe Oncologie du Centre de recherche du CHU de Québec-Université Laval, Québec, Canada
| | - Didier Trouche
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Yvan Canitrot
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail:
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de Krijger I, van der Torre J, Peuscher MH, Eder M, Jacobs JJL. H3K36 dimethylation by MMSET promotes classical non-homologous end-joining at unprotected telomeres. Oncogene 2020; 39:4814-4827. [PMID: 32472076 PMCID: PMC7299843 DOI: 10.1038/s41388-020-1334-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/12/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Abstract
The epigenetic environment plays an important role in DNA damage recognition and repair, both at DNA double-strand breaks and at deprotected telomeres. To increase understanding on how DNA damage responses (DDR) at deprotected telomeres are regulated by modification and remodeling of telomeric chromatin we screened 38 methyltransferases for their ability to promote telomere dysfunction-induced genomic instability. As top hit we identified MMSET, a histone methyltransferase (HMT) causally linked to multiple myeloma and Wolf-Hirschhorn syndrome. We show that MMSET promotes non-homologous end-joining (NHEJ) at deprotected telomeres through Ligase4-dependent classical NHEJ, and does not contribute to Ligase3-dependent alternative NHEJ. Moreover, we show that this is dependent on the catalytic activity of MMSET, enabled by its SET-domain. Indeed, in absence of MMSET H3K36-dimethylation (H3K36me2) decreases, both globally and at subtelomeric regions. Interestingly, the level of MMSET-dependent H3K36me2 directly correlates with NHEJ-efficiency. We show that MMSET depletion does not impact on recognition of deprotected telomeres by the DDR-machinery or on subsequent recruitment of DDR-factors acting upstream or at the level of DNA repair pathway choice. Our data are most consistent with an important role for H3K36me2 in more downstream steps of the DNA repair process. Moreover, we find additional H3K36me2-specific HMTs to contribute to NHEJ at deprotected telomeres, further emphasizing the importance of H3K36me2 in DNA repair.
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Affiliation(s)
- Inge de Krijger
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Jaco van der Torre
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Marieke H Peuscher
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Mathias Eder
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Jacqueline J L Jacobs
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
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Vítor AC, Huertas P, Legube G, de Almeida SF. Studying DNA Double-Strand Break Repair: An Ever-Growing Toolbox. Front Mol Biosci 2020; 7:24. [PMID: 32154266 PMCID: PMC7047327 DOI: 10.3389/fmolb.2020.00024] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/04/2020] [Indexed: 12/29/2022] Open
Abstract
To ward off against the catastrophic consequences of persistent DNA double-strand breaks (DSBs), eukaryotic cells have developed a set of complex signaling networks that detect these DNA lesions, orchestrate cell cycle checkpoints and ultimately lead to their repair. Collectively, these signaling networks comprise the DNA damage response (DDR). The current knowledge of the molecular determinants and mechanistic details of the DDR owes greatly to the continuous development of ground-breaking experimental tools that couple the controlled induction of DSBs at distinct genomic positions with assays and reporters to investigate DNA repair pathways, their impact on other DNA-templated processes and the specific contribution of the chromatin environment. In this review, we present these tools, discuss their pros and cons and illustrate their contribution to our current understanding of the DDR.
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Affiliation(s)
- Alexandra C Vítor
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Pablo Huertas
- Department of Genetics, University of Seville, Seville, Spain.,Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, Toulouse, France
| | - Sérgio F de Almeida
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
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42
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Sun Z, Zhang Y, Jia J, Fang Y, Tang Y, Wu H, Fang D. H3K36me3, message from chromatin to DNA damage repair. Cell Biosci 2020; 10:9. [PMID: 32021684 PMCID: PMC6995143 DOI: 10.1186/s13578-020-0374-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/09/2020] [Indexed: 12/17/2022] Open
Abstract
Histone marks control many cellular processes including DNA damage repair. This review will focus primarily on the active histone mark H3K36me3 in the regulation of DNA damage repair and the maintenance of genomic stability after DNA damage. There are diverse clues showing H3K36me3 participates in DNA damage response by directly recruiting DNA repair machinery to set the chromatin at a “ready” status, leading to a quick response upon damage. Reduced H3K36me3 is associated with low DNA repair efficiency. This review will also place a main emphasis on the H3K36me3-mediated DNA damage repair in the tumorigenesis of the newly found oncohistone mutant tumors. Gaining an understanding of different aspects of H3K36me3 in DNA damage repair, especially in cancers, would share the knowledge of chromatin and DNA repair to serve to the drug discovery and patient care.
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Affiliation(s)
- Zhongxing Sun
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Yanjun Zhang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Junqi Jia
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Yuan Fang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Yin Tang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Hongfei Wu
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
| | - Dong Fang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang China
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43
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Marnef A, Finoux AL, Arnould C, Guillou E, Daburon V, Rocher V, Mangeat T, Mangeot PE, Ricci EP, Legube G. A cohesin/HUSH- and LINC-dependent pathway controls ribosomal DNA double-strand break repair. Genes Dev 2019; 33:1175-1190. [PMID: 31395742 PMCID: PMC6719620 DOI: 10.1101/gad.324012.119] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 06/26/2019] [Indexed: 02/01/2023]
Abstract
The ribosomal DNA (rDNA) represents a particularly unstable locus undergoing frequent breakage. DNA double-strand breaks (DSBs) within rDNA induce both rDNA transcriptional repression and nucleolar segregation, but the link between the two events remains unclear. Here we found that DSBs induced on rDNA trigger transcriptional repression in a cohesin- and HUSH (human silencing hub) complex-dependent manner throughout the cell cycle. In S/G2 cells, transcriptional repression is further followed by extended resection within the interior of the nucleolus, DSB mobilization at the nucleolar periphery within nucleolar caps, and repair by homologous recombination. We showed that nuclear envelope invaginations frequently connect the nucleolus and that rDNA DSB mobilization, but not transcriptional repression, involves the nuclear envelope-associated LINC complex and the actin pathway. Altogether, our data indicate that rDNA break localization at the nucleolar periphery is not a direct consequence of transcriptional repression but rather is an active process that shares features with the mobilization of persistent DSB in active genes and heterochromatin.
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Affiliation(s)
- Aline Marnef
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Anne-Laure Finoux
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Coline Arnould
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Emmanuelle Guillou
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Virginie Daburon
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Vincent Rocher
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Thomas Mangeat
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
| | - Philippe E Mangeot
- International Center for Infectiology Research (CIRI), Ecole Normale Supérieure de Lyon (ENS), U1111, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR5308, Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1, Université Lyon, Lyon F-6900, France
| | - Emiliano P Ricci
- Laboratoire de Biologie et Modélisation de la Cellule (LBMC), Ecole Normale Supérieure de Lyon (ENS), U1210, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR5239, Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1, Université de Lyon, Lyon F-69007, France
| | - Gaëlle Legube
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, Toulouse 31062, France
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44
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Arnould C, Legube G. The Secret Life of Chromosome Loops upon DNA Double-Strand Break. J Mol Biol 2019; 432:724-736. [PMID: 31401119 PMCID: PMC7057266 DOI: 10.1016/j.jmb.2019.07.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
Abstract
DNA double-strand breaks (DSBs) are harmful lesions that severely challenge genomic integrity, and recent evidence suggests that DSBs occur more frequently on the genome than previously thought. These lesions activate a complex and multilayered response called the DNA damage response, which allows to coordinate their repair with the cell cycle progression. While the mechanistic details of repair processes have been narrowed, thanks to several decades of intense studies, our knowledge of the impact of DSB on chromatin composition and chromosome architecture is still very sparse. However, the recent development of various tools to induce DSB at annotated loci, compatible with next-generation sequencing-based approaches, is opening a new framework to tackle these questions. Here we discuss the influence of initial and DSB-induced chromatin conformation and the strong potential of 3C-based technologies to decipher the contribution of chromosome architecture during DSB repair.
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Affiliation(s)
- Coline Arnould
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Integrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France.
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Non-canonical DNA/RNA structures during Transcription-Coupled Double-Strand Break Repair: Roadblocks or Bona fide repair intermediates? DNA Repair (Amst) 2019; 81:102661. [PMID: 31331819 DOI: 10.1016/j.dnarep.2019.102661] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although long overlooked, it is now well understood that DNA does not systematically assemble into a canonical double helix, known as B-DNA, throughout the entire genome but can also accommodate other structures including DNA hairpins, G-quadruplexes and RNA:DNA hybrids. Notably, these non-canonical DNA structures form preferentially at transcriptionally active loci. Acting as replication roadblocks and being targeted by multiple machineries, these structures weaken the genome and render it prone to damage, including DNA double-strand breaks (DSB). In addition, secondary structures also further accumulate upon DSB formation. Here we discuss the potential functions of pre-existing or de novo formed nucleic acid structures, as bona fide repair intermediates or repair roadblocks, especially during Transcription-Coupled DNA Double-Strand Break repair (TC-DSBR), and provide an update on the specialized protein complexes displaying the ability to remove these structures to safeguard genome integrity.
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46
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Suzuki H, Okamoto-Katsuyama M, Suwa T, Maeda R, Tamura TA, Yamaguchi Y. TLP-mediated global transcriptional repression after double-strand DNA breaks slows down DNA repair and induces apoptosis. Sci Rep 2019; 9:4868. [PMID: 30890736 PMCID: PMC6425004 DOI: 10.1038/s41598-019-41057-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/18/2019] [Indexed: 11/16/2022] Open
Abstract
Transcription and DNA damage repair act in a coordinated manner. Recent studies have shown that double-strand DNA breaks (DSBs) are repaired in a transcription-coupled manner. Active transcription results in a faster recruitment of DSB repair factors and expedites DNA repair. On the other hand, transcription is repressed by DNA damage through multiple mechanisms. We previously reported that TLP, a TATA box-binding protein (TBP) family member that functions as a transcriptional regulator, is also involved in DNA damage-induced apoptosis. However, the mechanism by which TLP affects DNA damage response was largely unknown. Here we show that TLP-mediated global transcriptional repression after DSBs is crucial for apoptosis induction by DNA-damaging agents such as etoposide and doxorubicin. Compared to control cells, TLP-knockdown cells were resistant to etoposide-induced apoptosis and exhibited an elevated level of global transcription after etoposide exposure. DSBs were efficiently removed in transcriptionally hyperactive TLP-knockdown cells. However, forced transcriptional shutdown using transcriptional inhibitors α-amanitin and 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB) slowed down DSB repair and resensitized TLP-knockdown cells to etoposide. Taken together, these results indicate that TLP is a critical determinant as to how cells respond to DSBs and triggers apoptosis to cells that have sustained DNA damage.
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Affiliation(s)
- Hidefumi Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8501, Japan
| | - Mayumi Okamoto-Katsuyama
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8501, Japan
| | - Tetsufumi Suwa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8501, Japan
| | - Ryo Maeda
- Graduate School of Science, Chiba University, 1-33 Yayoicho, Chiba, 263-8522, Japan
| | - Taka-Aki Tamura
- Graduate School of Science, Chiba University, 1-33 Yayoicho, Chiba, 263-8522, Japan
| | - Yuki Yamaguchi
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 226-8501, Japan.
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Ballinger TJ, Bouwman BAM, Mirzazadeh R, Garnerone S, Crosetto N, Semple CA. Modeling double strand break susceptibility to interrogate structural variation in cancer. Genome Biol 2019; 20:28. [PMID: 30736820 PMCID: PMC6368699 DOI: 10.1186/s13059-019-1635-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/17/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Structural variants (SVs) are known to play important roles in a variety of cancers, but their origins and functional consequences are still poorly understood. Many SVs are thought to emerge from errors in the repair processes following DNA double strand breaks (DSBs). RESULTS We used experimentally quantified DSB frequencies in cell lines with matched chromatin and sequence features to derive the first quantitative genome-wide models of DSB susceptibility. These models are accurate and provide novel insights into the mutational mechanisms generating DSBs. Models trained in one cell type can be successfully applied to others, but a substantial proportion of DSBs appear to reflect cell type-specific processes. Using model predictions as a proxy for susceptibility to DSBs in tumors, many SV-enriched regions appear to be poorly explained by selectively neutral mutational bias alone. A substantial number of these regions show unexpectedly high SV breakpoint frequencies given their predicted susceptibility to mutation and are therefore credible targets of positive selection in tumors. These putatively positively selected SV hotspots are enriched for genes previously shown to be oncogenic. In contrast, several hundred regions across the genome show unexpectedly low levels of SVs, given their relatively high susceptibility to mutation. These novel coldspot regions appear to be subject to purifying selection in tumors and are enriched for active promoters and enhancers. CONCLUSIONS We conclude that models of DSB susceptibility offer a rigorous approach to the inference of SVs putatively subject to selection in tumors.
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Affiliation(s)
- Tracy J. Ballinger
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU UK
| | - Britta A. M. Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Reza Mirzazadeh
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Silvano Garnerone
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Colin A. Semple
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU UK
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DNA damage and genome instability by G-quadruplex ligands are mediated by R loops in human cancer cells. Proc Natl Acad Sci U S A 2018; 116:816-825. [PMID: 30591567 DOI: 10.1073/pnas.1810409116] [Citation(s) in RCA: 199] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
G quadruplexes (G4s) and R loops are noncanonical DNA structures that can regulate basic nuclear processes and trigger DNA damage, genome instability, and cell killing. By different technical approaches, we here establish that specific G4 ligands stabilize G4s and simultaneously increase R-loop levels within minutes in human cancer cells. Genome-wide mapping of R loops showed that the studied G4 ligands likely cause the spreading of R loops to adjacent regions containing G4 structures, preferentially at 3'-end regions of expressed genes, which are partially ligand-specific. Overexpression of an exogenous human RNaseH1 rescued DNA damage induced by G4 ligands in BRCA2-proficient and BRCA2-silenced cancer cells. Moreover, even if the studied G4 ligands increased noncanonical DNA structures at similar levels in nuclear chromatin, their cellular effects were different in relation to cell-killing activity and stimulation of micronuclei, a hallmark of genome instability. Our findings therefore establish that G4 ligands can induce DNA damage by an R loop-dependent mechanism that can eventually lead to different cellular consequences depending on the chemical nature of the ligands.
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Quantifying site-specific chromatin mechanics and DNA damage response. Sci Rep 2018; 8:18084. [PMID: 30591710 PMCID: PMC6308236 DOI: 10.1038/s41598-018-36343-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 11/14/2018] [Indexed: 01/06/2023] Open
Abstract
DNA double-strand breaks pose a direct threat to genomic stability. Studies of DNA damage and chromatin dynamics have yielded opposing results that support either increased or decreased chromatin motion after damage. In this study, we independently measure the dynamics of transcriptionally active or repressed chromatin regions using particle tracking microrheology. We find that the baseline motion of transcriptionally repressed regions of chromatin are significantly less mobile than transcriptionally active chromatin, which is statistically similar to the bulk motion of chromatin within the nucleus. Site specific DNA damage using KillerRed tags induced in loci within repressed chromatin causes an increased motion, while loci within transcriptionally active regions remains unchanged at similar time scales. We also observe a time-dependent response associated with a further increase in chromatin decondensation. Global induction of damage with bleocin displays similar trends of chromatin decondensation and increased mobility only at 53BP1-labeled damage sites but not at non-damaged sites, indicating that chromatin dynamics are tightly regulated locally after damage. These results shed light on the evolution of the local and global DNA damage response associated with chromatin remodeling and dynamics, with direct implications for their role in repair.
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Rpd3L Contributes to the DNA Damage Sensitivity of Saccharomyces cerevisiae Checkpoint Mutants. Genetics 2018; 211:503-513. [PMID: 30559326 PMCID: PMC6366903 DOI: 10.1534/genetics.118.301817] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 11/26/2018] [Indexed: 12/26/2022] Open
Abstract
DNA replication forks that are stalled by DNA damage activate an S-phase checkpoint that prevents irreversible fork arrest and cell death. The increased cell death caused by DNA damage in budding yeast cells lacking the Rad53 checkpoint protein kinase is partially suppressed by deletion of the EXO1 gene. Using a whole-genome sequencing approach, we identified two additional genes, RXT2 and RPH1, whose mutation can also partially suppress this DNA damage sensitivity. We provide evidence that RXT2 and RPH1 act in a common pathway, which is distinct from the EXO1 pathway. Analysis of additional mutants indicates that suppression works through the loss of the Rpd3L histone deacetylase complex. Our results suggest that the loss or absence of histone acetylation, perhaps at stalled forks, may contribute to cell death in the absence of a functional checkpoint.
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