1
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Boukoura S, Larsen DH. Nucleolar organization and ribosomal DNA stability in response to DNA damage. Curr Opin Cell Biol 2024; 89:102380. [PMID: 38861757 DOI: 10.1016/j.ceb.2024.102380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/13/2024]
Abstract
Eukaryotic nuclei are structured into sub-compartments orchestrating various cellular functions. The nucleolus is the largest nuclear organelle: a biomolecular condensate with an architecture composed of immiscible fluids facilitating ribosome biogenesis. The nucleolus forms upon the transcription of the repetitive ribosomal RNA genes (rDNA) that cluster in this compartment. rDNA is intrinsically unstable and prone to rearrangements and copy number variation. Upon DNA damage, a specialized nucleolar-DNA Damage Response (n-DDR) is activated: nucleolar transcription is inhibited, the architecture is rearranged, and rDNA is relocated to the nucleolar periphery. Recent data have highlighted how the composition of nucleoli, its structure, chemical and physical properties, contribute to rDNA stability. In this mini-review we focus on recent data that start to reveal how nucleolar composition and the n-DDR work together to ensure rDNA integrity.
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Affiliation(s)
- Stavroula Boukoura
- Nucleolar Stress and Disease Group, Danish Cancer Institute, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Dorthe Helena Larsen
- Nucleolar Stress and Disease Group, Danish Cancer Institute, Strandboulevarden 49, 2100 Copenhagen, Denmark.
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2
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Di Nisio E, Manzini V, Licursi V, Negri R. To Erase or Not to Erase: Non-Canonical Catalytic Functions and Non-Catalytic Functions of Members of Histone Lysine Demethylase Families. Int J Mol Sci 2024; 25:6900. [PMID: 39000010 PMCID: PMC11241480 DOI: 10.3390/ijms25136900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/12/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
Histone lysine demethylases (KDMs) play an essential role in biological processes such as transcription regulation, RNA maturation, transposable element control, and genome damage sensing and repair. In most cases, their action requires catalytic activities, but non-catalytic functions have also been shown in some KDMs. Indeed, some strictly KDM-related proteins and some KDM isoforms do not act as histone demethylase but show other enzymatic activities or relevant non-enzymatic functions in different cell types. Moreover, many studies have reported on functions potentially supported by catalytically dead mutant KDMs. This is probably due to the versatility of the catalytical core, which can adapt to assume different molecular functions, and to the complex multi-domain structure of these proteins which encompasses functional modules for targeting histone modifications, promoting protein-protein interactions, or recognizing nucleic acid structural motifs. This rich modularity and the availability of multiple isoforms in the various classes produced variants with enzymatic functions aside from histone demethylation or variants with non-catalytical functions during the evolution. In this review we will catalog the proteins with null or questionable demethylase activity and predicted or validated inactive isoforms, summarizing what is known about their alternative functions. We will then go through some experimental evidence for the non-catalytical functions of active KDMs.
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Affiliation(s)
- Elena Di Nisio
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (E.D.N.); (V.M.)
| | - Valeria Manzini
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (E.D.N.); (V.M.)
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy, 00185 Rome, Italy;
| | - Valerio Licursi
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy, 00185 Rome, Italy;
| | - Rodolfo Negri
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (E.D.N.); (V.M.)
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy, 00185 Rome, Italy;
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3
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González-Arzola K. The nucleolus: Coordinating stress response and genomic stability. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195029. [PMID: 38642633 DOI: 10.1016/j.bbagrm.2024.195029] [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: 11/15/2023] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
The perception that the nucleoli are merely the organelles where ribosome biogenesis occurs is challenged. Only around 30 % of nucleolar proteins are solely involved in producing ribosomes. Instead, the nucleolus plays a critical role in controlling protein trafficking during stress and, according to its dynamic nature, undergoes continuous protein exchange with nucleoplasm under various cellular stressors. Hence, the concept of nucleolar stress has evolved as cellular insults that disrupt the structure and function of the nucleolus. Considering the emerging role of this organelle in DNA repair and the fact that rDNAs are the most fragile genomic loci, therapies targeting the nucleoli are increasingly being developed. Besides, drugs that target ribosome synthesis and induce nucleolar stress can be used in cancer therapy. In contrast, agents that regulate nucleolar activity may be a potential treatment for neurodegeneration caused by abnormal protein accumulation in the nucleolus. Here, I explore the roles of nucleoli beyond their ribosomal functions, highlighting the factors triggering nucleolar stress and their impact on genomic stability.
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Affiliation(s)
- Katiuska González-Arzola
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, 41012 Seville, Spain.
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4
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van Bueren MAE, Janssen A. The impact of chromatin on double-strand break repair: Imaging tools and discoveries. DNA Repair (Amst) 2024; 133:103592. [PMID: 37976899 DOI: 10.1016/j.dnarep.2023.103592] [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: 07/27/2023] [Revised: 10/16/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Eukaryotic nuclei are constantly being exposed to factors that break or chemically modify the DNA. Accurate repair of this DNA damage is crucial to prevent DNA mutations and maintain optimal cell function. To overcome the detrimental effects of DNA damage, a multitude of repair pathways has evolved. These pathways need to function properly within the different chromatin domains present in the nucleus. Each of these domains exhibit distinct molecular- and bio-physical characteristics that can influence the response to DNA damage. In particular, chromatin domains highly enriched for repetitive DNA sequences, such as nucleoli, centromeres and pericentromeric heterochromatin require tailored repair mechanisms to safeguard genome stability. Work from the past decades has led to the development of innovative imaging tools as well as inducible DNA damage techniques to gain new insights into the impact of these repetitive chromatin domains on the DNA repair process. Here we summarize these tools with a particular focus on Double-Strand Break (DSB) repair, and discuss the insights gained into our understanding of the influence of chromatin domains on DSB -dynamics and -repair pathway choice.
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Affiliation(s)
- Marit A E van Bueren
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Aniek Janssen
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
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5
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Guang Z, Min Z, Jun-Tan L, Tian-Xu D, Xiang G. Single-cell protein activity analysis reveals a novel subpopulation of chondrocytes and the corresponding key master regulator proteins associated with anti-senescence and OA progression. Front Immunol 2023; 14:1077003. [PMID: 37033917 PMCID: PMC10077735 DOI: 10.3389/fimmu.2023.1077003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 03/09/2023] [Indexed: 04/11/2023] Open
Abstract
Background Osteoarthritis (OA) is a prevalent senescence-related disease with substantial joint pain, loss of joint function, and cartilage degeneration. Because of the paucity of single-cell studies of OA and the gene dropout problem of single-cell RNA sequencing, it is difficult to acquire an in-depth understanding of the molecular characteristics of various chondrocyte clusters. Methods Here, we aimed to provide new insights into chondrocyte senescence and a rationale for the development of effective intervention strategies for OA by using published single-cell RNA-sequencing data sets and the metaVIPER algorithm (Virtual Inference of Protein activity by Enriched Regulon). This algorithm was employed to present a proteome catalog of 62,449 chondrocytes from the cartilage of healthy individuals and OA patients at single-cell resolution. Furthermore, histopathologic analysis was carried out in cartilage samples from clinical patients and experimental mouse models of OA to validate above results. Results We identified 16 protein-activity-based chondrocyte clusters as well as the underlying master regulators in each cluster. By assessing the enrichment score of each cluster in bulk RNA-sequencing data, followed by gene-set variation analysis, we preliminarily identified a novel subpopulation of chondrocytes (cluster 3). This clinically relevant cluster was predicted to be the main chondrocyte cluster responsible for maintaining cellular homeostasis and anti-senescence. Specifically, we uncovered a set of the key leading-edge proteins of cluster 3 by validating the robustness of the above results using another human chondrocyte single-cell RNA-sequencing data set, consisting of 24,675 chondrocytes. Furthermore, cartilage samples from clinical patients and experimental mouse models of OA were used to evaluate the expression patterns of these leading-edge proteins, and the results indicated that NDRG2, TSPYL2, JMJD6 and HMGB2 are closely associated with OA pathogenesis and might play critical roles in modulating cellular homeostasis and anti-senescence in chondrocytes. Conclusion Our study revealed a novel subpopulation of chondrocytes that are critical for anti-progression of OA and the corresponding master regulator proteins, which might serve as therapeutic targets in OA.
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Affiliation(s)
- Zhao Guang
- Department of Orthopedics, The Fourth Hospital of China Medical University, Shenyang, China
| | - Zhang Min
- Department of Obstetrics, The Fourth Hospital of China Medical University, Shenyang, China
| | - Li Jun-Tan
- Department of Sport Medicine and Joint Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Dou Tian-Xu
- Department of Sport Medicine and Joint Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Gao Xiang
- Department of Orthopedics, The Fourth Hospital of China Medical University, Shenyang, China
- *Correspondence: Gao Xiang,
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6
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Zhou J, Simon JM, Liao C, Zhang C, Hu L, Zurlo G, Liu X, Fan C, Hepperla A, Jia L, Tcheuyap VT, Zhong H, Elias R, Ye J, Henne WM, Kapur P, Nijhawan D, Brugarolas J, Zhang Q. An oncogenic JMJD6-DGAT1 axis tunes the epigenetic regulation of lipid droplet formation in clear cell renal cell carcinoma. Mol Cell 2022; 82:3030-3044.e8. [PMID: 35764091 PMCID: PMC9391320 DOI: 10.1016/j.molcel.2022.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 03/15/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022]
Abstract
Characterized by intracellular lipid droplet accumulation, clear cell renal cell carcinoma (ccRCC) is resistant to cytotoxic chemotherapy and is a lethal disease. Through an unbiased siRNA screen of 2-oxoglutarate (2-OG)-dependent enzymes, which play a critical role in tumorigenesis, we identified Jumonji domain-containing 6 (JMJD6) as an essential gene for ccRCC tumor development. The downregulation of JMJD6 abolished ccRCC colony formation in vitro and inhibited orthotopic tumor growth in vivo. Integrated ChIP-seq and RNA-seq analyses uncovered diacylglycerol O-acyltransferase 1 (DGAT1) as a critical JMJD6 effector. Mechanistically, JMJD6 interacted with RBM39 and co-occupied DGAT1 gene promoter with H3K4me3 to induce DGAT1 expression. JMJD6 silencing reduced DGAT1, leading to decreased lipid droplet formation and tumorigenesis. The pharmacological inhibition (or depletion) of DGAT1 inhibited lipid droplet formation in vitro and ccRCC tumorigenesis in vivo. Thus, the JMJD6-DGAT1 axis represents a potential new therapeutic target for ccRCC.
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Affiliation(s)
- Jin Zhou
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jeremy M Simon
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Genetics, Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Chengheng Liao
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Cheng Zhang
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lianxin Hu
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Giada Zurlo
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xijuan Liu
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Cheng Fan
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Austin Hepperla
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Genetics, Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Liwei Jia
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vanina Toffessi Tcheuyap
- Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hua Zhong
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Roy Elias
- Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jin Ye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Payal Kapur
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Deepak Nijhawan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - James Brugarolas
- Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Qing Zhang
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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7
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Cockman ME, Sugimoto Y, Pegg HB, Masson N, Salah E, Tumber A, Flynn HR, Kirkpatrick JM, Schofield CJ, Ratcliffe PJ. Widespread hydroxylation of unstructured lysine-rich protein domains by JMJD6. Proc Natl Acad Sci U S A 2022; 119:e2201483119. [PMID: 35930668 PMCID: PMC9371714 DOI: 10.1073/pnas.2201483119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/24/2022] [Indexed: 11/18/2022] Open
Abstract
The Jumonji domain-containing protein JMJD6 is a 2-oxoglutarate-dependent dioxygenase associated with a broad range of biological functions. Cellular studies have implicated the enzyme in chromatin biology, transcription, DNA repair, mRNA splicing, and cotranscriptional processing. Although not all studies agree, JMJD6 has been reported to catalyze both hydroxylation of lysine residues and demethylation of arginine residues. However, despite extensive study and indirect evidence for JMJD6 catalysis in many cellular processes, direct assignment of JMJD6 catalytic substrates has been limited. Examination of a reported site of proline hydroxylation within a lysine-rich region of the tandem bromodomain protein BRD4 led us to conclude that hydroxylation was in fact on lysine and catalyzed by JMJD6. This prompted a wider search for JMJD6-catalyzed protein modifications deploying mass spectrometric methods designed to improve the analysis of such lysine-rich regions. Using lysine derivatization with propionic anhydride to improve the analysis of tryptic peptides and nontryptic proteolysis, we report 150 sites of JMJD6-catalyzed lysine hydroxylation on 48 protein substrates, including 19 sites of hydroxylation on BRD4. Most hydroxylations were within lysine-rich regions that are predicted to be unstructured; in some, multiple modifications were observed on adjacent lysine residues. Almost all of the JMJD6 substrates defined in these studies have been associated with membraneless organelle formation. Given the reported roles of lysine-rich regions in subcellular partitioning by liquid-liquid phase separation, our findings raise the possibility that JMJD6 may play a role in regulating such processes in response to stresses, including hypoxia.
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Affiliation(s)
- Matthew E. Cockman
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Yoichiro Sugimoto
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Hamish B. Pegg
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Norma Masson
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Eidarus Salah
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Anthony Tumber
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Helen R. Flynn
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Joanna M. Kirkpatrick
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Peter J. Ratcliffe
- Hypoxia Biology Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, United Kingdom
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8
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Tsaridou S, Velimezi G, Willenbrock F, Chatzifrangkeskou M, Elsayed W, Panagopoulos A, Karamitros D, Gorgoulis V, Lygerou Z, Roukos V, O'Neill E, Pefani DE. 53BP1-mediated recruitment of RASSF1A to ribosomal DNA breaks promotes local ATM signaling. EMBO Rep 2022; 23:e54483. [PMID: 35758159 PMCID: PMC9346497 DOI: 10.15252/embr.202154483] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 12/29/2022] Open
Abstract
DNA lesions occur across the genome and constitute a threat to cell viability; however, damage at specific genomic loci has a relatively greater impact on overall genome stability. The ribosomal RNA gene repeats (rDNA) are emerging fragile sites. Recent progress in understanding how the rDNA damage response is organized has highlighted a key role of adaptor proteins. Here, we show that the scaffold tumor suppressor RASSF1A is recruited to rDNA breaks. RASSF1A recruitment to double-strand breaks is mediated by 53BP1 and depends on RASSF1A phosphorylation at Serine 131 by ATM kinase. Employing targeted rDNA damage, we uncover that RASSF1A recruitment promotes local ATM signaling. RASSF1A silencing, a common epigenetic event during malignant transformation, results in persistent breaks, rDNA copy number alterations and decreased cell viability. Overall, we identify a novel role for RASSF1A at rDNA break sites, provide mechanistic insight into how the DNA damage response is organized in a chromatin context, and provide further evidence for how silencing of the RASSF1A tumor suppressor contributes to genome instability.
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Affiliation(s)
- Stavroula Tsaridou
- Department of Biology, School of Medicine, University of Patras, Patras, Greece
| | - Georgia Velimezi
- Department of Biology, School of Medicine, University of Patras, Patras, Greece.,Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | | | | | | | | | - Dimitris Karamitros
- Department of Physiology, School of Medicine, University of Patras, Patras, Greece
| | - Vassilis Gorgoulis
- Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,Laboratory of Histology and Embryology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Faculty of Biology, Medicine and Health, Manchester Academic Health Centre, University of Manchester, Manchester, UK.,Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Zoi Lygerou
- Department of Biology, School of Medicine, University of Patras, Patras, Greece
| | - Vassilis Roukos
- Department of Biology, School of Medicine, University of Patras, Patras, Greece.,Institute of Molecular Biology (IMB), Mainz, Germany
| | - Eric O'Neill
- Department of Oncology, University of Oxford, Oxford, UK
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9
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Gál Z, Nieto B, Boukoura S, Rasmussen AV, Larsen DH. Treacle Sticks the Nucleolar Responses to DNA Damage Together. Front Cell Dev Biol 2022; 10:892006. [PMID: 35646927 PMCID: PMC9133508 DOI: 10.3389/fcell.2022.892006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/21/2022] [Indexed: 01/05/2023] Open
Abstract
The importance of chromatin environment for DNA repair has gained increasing recognition in recent years. The nucleolus is the largest sub-compartment within the nucleus: it has distinct biophysical properties, selective protein retention, and houses the specialized ribosomal RNA genes (collectively referred to as rDNA) with a unique chromatin composition. These genes have high transcriptional activity and a repetitive nature, making them susceptible to DNA damage and resulting in the highest frequency of rearrangements across the genome. A distinct DNA damage response (DDR) secures the fidelity of this genomic region, the so-called nucleolar DDR (n-DDR). The composition of the n-DDR reflects the characteristics of nucleolar chromatin with the nucleolar protein Treacle (also referred to as TCOF1) as a central coordinator retaining several well-characterized DDR proteins in the nucleolus. In this review, we bring together data on the structure of Treacle, its known functions in ribosome biogenesis, and its involvement in multiple branches of the n-DDR to discuss their interconnection. Furthermore, we discuss how the functions of Treacle in ribosome biogenesis and in the n-DDR may contribute to Treacher Collins Syndrome, a disease caused by mutations in Treacle. Finally, we outline outstanding questions that need to be addressed for a more comprehensive understanding of Treacle, the n-DDR, and the coordination of ribosome biogenesis and DNA repair.
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10
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Loehr J, Kougnassoukou Tchara PE, Gonthier K, Noufi C, Linteau N, Audet-Walsh É, Lambert JP. A Nutrient-Based Cellular Model to Characterize Acetylation-Dependent Protein-Protein Interactions. Front Mol Biosci 2022; 9:831758. [PMID: 35402505 PMCID: PMC8984119 DOI: 10.3389/fmolb.2022.831758] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/25/2022] [Indexed: 11/20/2022] Open
Abstract
Cellular homeostasis requires the orderly expression of thousands of transcripts. Gene expression is regulated by numerous proteins that recognize post-translational modifications—in particular, the acetylation of lysine residues (Kac) on histones. In addition to affecting the general condensation state of the chromatin, acetylated histones act as anchor points for bromodomain (BRD)-containing adapter proteins. BRDs are the primary Kac reader domains in humans, and proteins containing them act as chromatin scaffolds that organize large networks of interactions to regulate transcription. To characterize BRD-dependent interaction networks, we established cell lines in which histone acetylation is dependent on acetate supplementation. To do this, we used genome editing to knock out ATP citrate lyase (ACLY), the enzyme responsible for converting citrate to oxaloacetate and acetyl-CoA in the cytoplasm and nucleus. In our cellular model, removing acetate from the culture medium resulted in the rapid catabolism of acetylated histones to restore the nucleocytoplasmic acetyl-CoA pool. Here we report the use of our new model in functional proteomics studies to characterize BRD-dependent interaction networks on the chromatin.
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Affiliation(s)
- Jérémy Loehr
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
| | - Pata-Eting Kougnassoukou Tchara
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
- Big Data Research Center, Université Laval, Quebec, QC, Canada
| | - Kevin Gonthier
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
| | - Chahinez Noufi
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
| | - Naomie Linteau
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
| | - Étienne Audet-Walsh
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
| | - Jean-Philippe Lambert
- Department of Molecular Medicine and Cancer Research Center, Université Laval, Quebec, QC, Canada
- CHU de Québec Research Center, Quebec, QC, Canada
- Big Data Research Center, Université Laval, Quebec, QC, Canada
- *Correspondence: Jean-Philippe Lambert,
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11
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Velichko AK, Ovsyannikova N, Petrova NV, Luzhin AV, Vorobjeva M, Gavrikov AS, Mishin AS, Kireev II, Razin SV, Kantidze OL. Treacle and TOPBP1 control replication stress response in the nucleolus. J Cell Biol 2021; 220:212262. [PMID: 34100862 PMCID: PMC8190600 DOI: 10.1083/jcb.202008085] [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: 08/16/2020] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 12/22/2022] Open
Abstract
Replication stress is one of the main sources of genome instability. Although the replication stress response in eukaryotic cells has been extensively studied, almost nothing is known about the replication stress response in nucleoli. Here, we demonstrate that initial replication stress-response factors, such as RPA, TOPBP1, and ATR, are recruited inside the nucleolus in response to drug-induced replication stress. The role of TOPBP1 goes beyond the typical replication stress response; it interacts with the low-complexity nucleolar protein Treacle (also referred to as TCOF1) and forms large Treacle-TOPBP1 foci inside the nucleolus. In response to replication stress, Treacle and TOPBP1 facilitate ATR signaling at stalled replication forks, reinforce ATR-mediated checkpoint activation inside the nucleolus, and promote the recruitment of downstream replication stress response proteins inside the nucleolus without forming nucleolar caps. Characterization of the Treacle-TOPBP1 interaction mode leads us to propose that these factors can form a molecular platform for efficient stress response in the nucleolus.
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Affiliation(s)
- Artem K Velichko
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Natalia Ovsyannikova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | | | - Artem V Luzhin
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Maria Vorobjeva
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Alexey S Gavrikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Alexander S Mishin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Igor I Kireev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology, and Perinatology, Moscow, Russia
| | - Sergey V Razin
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Omar L Kantidze
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
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12
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The Ribosomal Gene Loci-The Power behind the Throne. Genes (Basel) 2021; 12:genes12050763. [PMID: 34069807 PMCID: PMC8157237 DOI: 10.3390/genes12050763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Nucleoli form around actively transcribed ribosomal RNA (rRNA) genes (rDNA), and the morphology and location of nucleolus-associated genomic domains (NADs) are linked to the RNA Polymerase I (Pol I) transcription status. The number of rDNA repeats (and the proportion of actively transcribed rRNA genes) is variable between cell types, individuals and disease state. Substantial changes in nucleolar morphology and size accompanied by concomitant changes in the Pol I transcription rate have long been documented during normal cell cycle progression, development and malignant transformation. This demonstrates how dynamic the nucleolar structure can be. Here, we will discuss how the structure of the rDNA loci, the nucleolus and the rate of Pol I transcription are important for dynamic regulation of global gene expression and genome stability, e.g., through the modulation of long-range genomic interactions with the suppressive NAD environment. These observations support an emerging paradigm whereby the rDNA repeats and the nucleolus play a key regulatory role in cellular homeostasis during normal development as well as disease, independent of their role in determining ribosome capacity and cellular growth rates.
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13
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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: 31] [Impact Index Per Article: 7.8] [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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14
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Fletcher SC, Coleman ML. Human 2-oxoglutarate-dependent oxygenases: nutrient sensors, stress responders, and disease mediators. Biochem Soc Trans 2020; 48:1843-1858. [PMID: 32985654 PMCID: PMC7609023 DOI: 10.1042/bst20190333] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/30/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022]
Abstract
Fe(II)/2-oxoglutarate (2OG)-dependent oxygenases are a conserved enzyme class that catalyse diverse oxidative reactions across nature. In humans, these enzymes hydroxylate a broad range of biological substrates including DNA, RNA, proteins and some metabolic intermediates. Correspondingly, members of the 2OG-dependent oxygenase superfamily have been linked to fundamental biological processes, and found dysregulated in numerous human diseases. Such findings have stimulated efforts to understand both the biochemical activities and cellular functions of these enzymes, as many have been poorly studied. In this review, we focus on human 2OG-dependent oxygenases catalysing the hydroxylation of protein and polynucleotide substrates. We discuss their modulation by changes in the cellular microenvironment, particularly with respect to oxygen, iron, 2OG and the effects of oncometabolites. We also describe emerging evidence that these enzymes are responsive to cellular stresses including hypoxia and DNA damage. Moreover, we examine how dysregulation of 2OG-dependent oxygenases is associated with human disease, and the apparent paradoxical role for some of these enzymes during cancer development. Finally, we discuss some of the challenges associated with assigning biochemical activities and cellular functions to 2OG-dependent oxygenases.
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Affiliation(s)
- Sally C. Fletcher
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, U.K
| | - Mathew L. Coleman
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, U.K
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