1
|
Correll CC, Rudloff U, Schmit JD, Ball DA, Karpova TS, Balzer E, Dundr M. Crossing boundaries of light microscopy resolution discerns novel assemblies in the nucleolus. Histochem Cell Biol 2024; 162:161-183. [PMID: 38758429 DOI: 10.1007/s00418-024-02297-7] [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] [Accepted: 05/03/2024] [Indexed: 05/18/2024]
Abstract
The nucleolus is the largest membraneless organelle and nuclear body in mammalian cells. It is primarily involved in the biogenesis of ribosomes, essential macromolecular machines responsible for synthesizing all proteins required by the cell. The assembly of ribosomes is evolutionarily conserved and accounts for the most energy-consuming cellular process needed for cell growth, proliferation, and homeostasis. Despite the significance of this process, the substructural mechanistic principles of the nucleolar function in preribosome biogenesis have only recently begun to emerge. Here, we provide a new perspective using advanced super-resolution microscopy and single-molecule MINFLUX nanoscopy on the mechanistic principles governing ribosomal RNA-seeded nucleolar formation and the resulting tripartite suborganization of the nucleolus driven, in part, by liquid-liquid phase separation. With recent advances in the cryogenic electron microscopy (cryoEM) structural analysis of ribosome biogenesis intermediates, we highlight the current understanding of the step-wise assembly of preribosomal subunits in the nucleolus. Finally, we address how novel anticancer drug candidates target early steps in ribosome biogenesis to exploit these essential dependencies for growth arrest and tumor control.
Collapse
Affiliation(s)
- Carl C Correll
- Center for Proteomics and Molecular Therapeutics and Biochemistry and Molecular Biology, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, IL, 60064, USA
| | - Udo Rudloff
- Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jeremy D Schmit
- Department of Physics, Kansas State University, Manhattan, KS, 66506, USA
| | - David A Ball
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tatiana S Karpova
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eric Balzer
- Nikon Instruments Inc., Melville, NY, 11747, USA
| | - Miroslav Dundr
- Rare Tumor Initiative, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
- Center for Cancer Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, IL, 60064, USA.
| |
Collapse
|
2
|
Baralić K, Božović P, Đukić-Ćosić D. Deciphering the molecular landscape of ionising radiation-induced eye damage with the help of genomic data mining. Arh Hig Rada Toksikol 2024; 75:91-101. [PMID: 38963141 PMCID: PMC11223508 DOI: 10.2478/aiht-2024-75-3817] [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: 01/01/2024] [Revised: 01/01/2024] [Accepted: 05/01/2024] [Indexed: 07/05/2024] Open
Abstract
Even at low levels, exposure to ionising radiation can lead to eye damage. However, the underlying molecular mechanisms are not yet fully understood. We aimed to address this gap with a comprehensive in silico approach to the issue. For this purpose we relied on the Comparative Toxicogenomics Database (CTD), ToppGene Suite, Cytoscape, GeneMANIA, and Metascape to identify six key regulator genes associated with radiation-induced eye damage (ATM, CRYAB, SIRT1, TGFB1, TREX1, and YAP1), all of which have physical interactions. Some of the identified molecular functions revolve around DNA repair mechanisms, while others are involved in protein binding, enzymatic activities, metabolic processes, and post-translational protein modifications. The biological processes are mostly centred on response to DNA damage, the p53 signalling pathway in particular. We identified a significant role of several miRNAs, such as hsa-miR-183 and hsamiR-589, in the mechanisms behind ionising radiation-induced eye injuries. Our study offers a valuable method for gaining deeper insights into the adverse effects of radiation exposure.
Collapse
Affiliation(s)
- Katarina Baralić
- University of Belgrade, Faculty of Pharmacy, Department of Toxicology “Akademik Danilo Soldatović“, Belgrade, Serbia
| | - Predrag Božović
- University of Belgrade Vinča Institute of Nuclear Sciences, Department of Radiation and Environmental Protection, Belgrade, Serbia
| | - Danijela Đukić-Ćosić
- University of Belgrade, Faculty of Pharmacy, Department of Toxicology “Akademik Danilo Soldatović“, Belgrade, Serbia
| |
Collapse
|
3
|
Hong S, Lee HG, Huh WK. ARV1 deficiency induces lipid bilayer stress and enhances rDNA stability by activating the unfolded protein response in Saccharomyces cerevisiae. J Biol Chem 2024; 300:107273. [PMID: 38588806 PMCID: PMC11089378 DOI: 10.1016/j.jbc.2024.107273] [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: 08/14/2023] [Revised: 03/18/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024] Open
Abstract
The stability of ribosomal DNA (rDNA) is maintained through transcriptional silencing by the NAD+-dependent histone deacetylase Sir2 in Saccharomyces cerevisiae. Alongside proteostasis, rDNA stability is a crucial factor regulating the replicative lifespan of S. cerevisiae. The unfolded protein response (UPR) is induced by misfolding of proteins or an imbalance of membrane lipid composition and is responsible for degrading misfolded proteins and restoring endoplasmic reticulum (ER) membrane homeostasis. Recent investigations have suggested that the UPR can extend the replicative lifespan of yeast by enhancing protein quality control mechanisms, but the relationship between the UPR and rDNA stability remains unknown. In this study, we found that the deletion of ARV1, which encodes an ER protein of unknown molecular function, activates the UPR by inducing lipid bilayer stress. In arv1Δ cells, the UPR and the cell wall integrity pathway are activated independently of each other, and the high osmolarity glycerol (HOG) pathway is activated in a manner dependent on Ire1, which mediates the UPR. Activated Hog1 translocates the stress response transcription factor Msn2 to the nucleus, where it promotes the expression of nicotinamidase Pnc1, a well-known Sir2 activator. Following Sir2 activation, rDNA silencing and rDNA stability are promoted. Furthermore, the loss of other ER proteins, such as Pmt1 or Bst1, and ER stress induced by tunicamycin or inositol depletion also enhance rDNA stability in a Hog1-dependent manner. Collectively, these findings suggest that the induction of the UPR enhances rDNA stability in S. cerevisiae by promoting the Msn2-Pnc1-Sir2 pathway in a Hog1-dependent manner.
Collapse
Affiliation(s)
- Sujin Hong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyeon-Geun Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
| |
Collapse
|
4
|
Shatskikh AS, Fefelova EA, Klenov MS. Functions of RNAi Pathways in Ribosomal RNA Regulation. Noncoding RNA 2024; 10:19. [PMID: 38668377 PMCID: PMC11054153 DOI: 10.3390/ncrna10020019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 04/29/2024] Open
Abstract
Argonaute proteins, guided by small RNAs, play crucial roles in gene regulation and genome protection through RNA interference (RNAi)-related mechanisms. Ribosomal RNAs (rRNAs), encoded by repeated rDNA units, constitute the core of the ribosome being the most abundant cellular transcripts. rDNA clusters also serve as sources of small RNAs, which are loaded into Argonaute proteins and are able to regulate rDNA itself or affect other gene targets. In this review, we consider the impact of small RNA pathways, specifically siRNAs and piRNAs, on rRNA gene regulation. Data from diverse eukaryotic organisms suggest the potential involvement of small RNAs in various molecular processes related to the rDNA transcription and rRNA fate. Endogenous siRNAs are integral to the chromatin-based silencing of rDNA loci in plants and have been shown to repress rDNA transcription in animals. Small RNAs also play a role in maintaining the integrity of rDNA clusters and may function in the cellular response to rDNA damage. Studies on the impact of RNAi and small RNAs on rRNA provide vast opportunities for future exploration.
Collapse
Affiliation(s)
- Aleksei S. Shatskikh
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia;
| | - Elena A. Fefelova
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia
| | - Mikhail S. Klenov
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| |
Collapse
|
5
|
de Luna Vitorino FN, Levy MJ, Mansano Wailemann RA, Lopes M, Silva ML, Sardiu ME, Garcia BA, Machado Motta MC, Oliveira CC, Armelin HA, Florens LA, Washburn MP, Pinheiro Chagas da Cunha J. The antiproliferative effect of FGF2 in K-Ras-driven tumor cells involves modulation of rRNA and the nucleolus. J Cell Sci 2023; 136:jcs260989. [PMID: 37921359 PMCID: PMC11166202 DOI: 10.1242/jcs.260989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 10/24/2023] [Indexed: 11/04/2023] Open
Abstract
The nucleolus is sensitive to stress and can orchestrate a chain of cellular events in response to stress signals. Despite being a growth factor, FGF2 has antiproliferative and tumor-suppressive functions in some cellular contexts. In this work, we investigated how the antiproliferative effect of FGF2 modulates chromatin-, nucleolus- and rDNA-associated proteins. The chromatin and nucleolar proteome indicated that FGF2 stimulation modulates proteins related to transcription, rRNA expression and chromatin-remodeling proteins. The global transcriptional rate and nucleolus area increased along with nucleolar disorganization upon 24 h of FGF2 stimulation. FGF2 stimulation induced immature rRNA accumulation by increasing rRNA transcription. The rDNA-associated protein analysis reinforced that FGF2 stimulus interferes with transcription and rRNA processing. RNA Pol I inhibition partially reversed the growth arrest induced by FGF2, indicating that changes in rRNA expression might be crucial for triggering the antiproliferative effect. Taken together, we demonstrate that the antiproliferative FGF2 stimulus triggers significant transcriptional changes and modulates the main cell transcription site, the nucleolus.
Collapse
Affiliation(s)
- Francisca N. de Luna Vitorino
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | | | - Rosangela A. Mansano Wailemann
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
| | - Mariana Lopes
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
| | - Mariana Loterio Silva
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
| | | | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Maria Cristina Machado Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Centro de Pesquisa em Medicina de Precisão, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21491-590, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ 21941-902, Brazil
| | - Carla Columbano Oliveira
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP 05508-000, Brazil
| | - Hugo Aguirre Armelin
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
| | | | | | - Julia Pinheiro Chagas da Cunha
- Laboratório de Ciclo Celular – Center of Toxins, Immune-Response and Cell Signalling – CeTICS, Instituto Butantan, São Paulo, SP 055503-900, Brazil
| |
Collapse
|
6
|
Rajshekar S, Adame-Arana O, Bajpai G, Lin K, Colmenares S, Safran S, Karpen GH. Affinity hierarchies and amphiphilic proteins underlie the co-assembly of nucleolar and heterochromatin condensates. RESEARCH SQUARE 2023:rs.3.rs-3385692. [PMID: 37841837 PMCID: PMC10571612 DOI: 10.21203/rs.3.rs-3385692/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Nucleoli are surrounded by Pericentromeric Heterochromatin (PCH), reflecting a close spatial association between the two largest biomolecular condensates in eukaryotic nuclei. This nuclear organizational feature is highly conserved and is disrupted in diseased states like senescence, however, the mechanisms driving PCH-nucleolar association are unclear. High-resolution live imaging during early Drosophila development revealed a highly dynamic process in which PCH and nucleolar formation is coordinated and interdependent. When nucleolus assembly was eliminated by deleting the ribosomal RNA genes (rDNA), PCH showed increased compaction and subsequent reorganization to a shell-like structure. In addition, in embryos lacking rDNA, some nucleolar proteins were redistributed into new bodies or 'neocondensates,' including enrichment in the core of the PCH shell. These observations, combined with physical modeling and simulations, suggested that nucleolar-PCH associations are mediated by a hierarchy of affinities between PCH, nucleoli, and 'amphiphilic' protein(s) that interact with both nucleolar and PCH components. This result was validated by demonstrating that the depletion of one candidate amphiphile, the nucleolar protein Pitchoune, significantly reduced PCH-nucleolar associations. Together, these results unveil a dynamic program for establishing nucleolar-PCH associations during animal development, demonstrate that nucleoli are required for normal PCH organization, and identify Pitchoune as an amphiphilic molecular link that promotes PCH-nucleolar associations. Finally, we propose that disrupting affinity hierarchies between interacting condensates can liberate molecules to form neocondensates or other aberrant structures that could contribute to cellular disease phenotypes.
Collapse
Affiliation(s)
- Srivarsha Rajshekar
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Omar Adame-Arana
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Gaurav Bajpai
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Kyle Lin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Serafin Colmenares
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Samuel Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
- Division of Biological Sciences and the Environment, Lawrence Berkeley National Laboratory, Berkeley, USA
| |
Collapse
|
7
|
Rajshekar S, Adame-Arana O, Bajpai G, Lin K, Colmenares S, Safran S, Karpen GH. Affinity hierarchies and amphiphilic proteins underlie the co-assembly of nucleolar and heterochromatin condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.547894. [PMID: 37808710 PMCID: PMC10557603 DOI: 10.1101/2023.07.06.547894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Nucleoli are surrounded by Pericentromeric Heterochromatin (PCH), reflecting a close spatial association between the two largest biomolecular condensates in eukaryotic nuclei. This nuclear organizational feature is highly conserved and is disrupted in diseased states like senescence, however, the mechanisms driving PCH-nucleolar association are unclear. High-resolution live imaging during early Drosophila development revealed a highly dynamic process in which PCH and nucleolar formation is coordinated and interdependent. When nucleolus assembly was eliminated by deleting the ribosomal RNA genes (rDNA), PCH showed increased compaction and subsequent reorganization to a shell-like structure. In addition, in embryos lacking rDNA, some nucleolar proteins were redistributed into new bodies or 'neocondensates,' including enrichment in the core of the PCH shell. These observations, combined with physical modeling and simulations, suggested that nucleolar-PCH associations are mediated by a hierarchy of affinities between PCH, nucleoli, and 'amphiphilic' protein(s) that interact with both nucleolar and PCH components. This result was validated by demonstrating that the depletion of one candidate amphiphile, the nucleolar protein Pitchoune, significantly reduced PCH-nucleolar associations. Together, these results unveil a dynamic program for establishing nucleolar-PCH associations during animal development, demonstrate that nucleoli are required for normal PCH organization, and identify Pitchoune as an amphiphilic molecular link that promotes PCH-nucleolar associations. Finally, we propose that disrupting affinity hierarchies between interacting condensates can liberate molecules to form neocondensates or other aberrant structures that could contribute to cellular disease phenotypes.
Collapse
Affiliation(s)
- Srivarsha Rajshekar
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Omar Adame-Arana
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Gaurav Bajpai
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Kyle Lin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Serafin Colmenares
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Samuel Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
- Division of Biological Sciences and the Environment, Lawrence Berkeley National Laboratory, Berkeley, USA
| |
Collapse
|
8
|
Lagunas-Rangel FA. The nucleolus of Giardia and its ribosomal biogenesis. Parasitol Res 2023; 122:1961-1971. [PMID: 37400534 DOI: 10.1007/s00436-023-07915-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/26/2023] [Indexed: 07/05/2023]
Abstract
Giardia duodenalis is a protozoan intestinal parasite that causes a significant number of infections worldwide each year, particularly in low-income and developing countries. Despite the availability of treatments for this parasitic infection, treatment failures are alarmingly common. As a result, new therapeutic strategies are urgently needed to effectively combat this disease. On the other hand, within the eukaryotic nucleus, the nucleolus stands out as the most prominent structure. It plays a crucial role in coordinating ribosome biogenesis and is involved in vital processes such as maintaining genome stability, regulating cell cycle progression, controlling cell senescence, and responding to stress. Given its significance, the nucleolus presents itself as a valuable target for selectively inducing cell death in undesirable cells, making it a potential avenue for anti-Giardia treatments. Despite its potential importance, the Giardia nucleolus remains poorly studied and often overlooked. In light of this, the objective of this study is to provide a detailed molecular description of the structure and function of the Giardia nucleolus, with a primary focus on its involvement in ribosomal biogenesis. Likewise, it discusses the targeting of the Giardia nucleolus as a therapeutic strategy, its feasibility, and the challenges involved.
Collapse
Affiliation(s)
- Francisco Alejandro Lagunas-Rangel
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2508, San Pedro Zacatenco, Gustavo A. Madero, 07360, Mexico City, Mexico.
| |
Collapse
|
9
|
Srivastava R, Singh R, Jauhari S, Lodhi N, Srivastava R. Histone Demethylase Modulation: Epigenetic Strategy to Combat Cancer Progression. EPIGENOMES 2023; 7:epigenomes7020010. [PMID: 37218871 DOI: 10.3390/epigenomes7020010] [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: 02/01/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
Epigenetic modifications are heritable, reversible changes in histones or the DNA that control gene functions, being exogenous to the genomic sequence itself. Human diseases, particularly cancer, are frequently connected to epigenetic dysregulations. One of them is histone methylation, which is a dynamically reversible and synchronously regulated process that orchestrates the three-dimensional epigenome, nuclear processes of transcription, DNA repair, cell cycle, and epigenetic functions, by adding or removing methylation groups to histones. Over the past few years, reversible histone methylation has become recognized as a crucial regulatory mechanism for the epigenome. With the development of numerous medications that target epigenetic regulators, epigenome-targeted therapy has been used in the treatment of malignancies and has shown meaningful therapeutic potential in preclinical and clinical trials. The present review focuses on the recent advances in our knowledge on the role of histone demethylases in tumor development and modulation, in emphasizing molecular mechanisms that control cancer cell progression. Finally, we emphasize current developments in the advent of new molecular inhibitors that target histone demethylases to regulate cancer progression.
Collapse
Affiliation(s)
- Rashmi Srivastava
- Department of Zoology, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, Uttar Pradesh, India
| | - Rubi Singh
- Department of Hematology, Bioreference Laboratories, Elmwood Park, NJ 07407, USA
| | - Shaurya Jauhari
- Division of Education, Training, and Assessment, Global Education Center, Infosys Limited, Mysuru 570027, Karnataka, India
| | - Niraj Lodhi
- Clinical Research (Research and Development Division) Mirna Analytics LLC, Harlem Bio-Space, New York, NY 10027, USA
| | - Rakesh Srivastava
- Molecular Biology and Microbiology, GenTox Research and Development, Lucknow 226001, Uttar Pradesh, India
| |
Collapse
|
10
|
Xu H, Shi L, Feng L, Wu F, Chen J, Qin Y, Dong X, Jiang Z, Li Y, Xia H, Lou J. Hexavalent chromium [Cr(VI)]-induced ribosomal DNA copy number variation and DNA damage responses and their associations with nucleolar protein HRAS in humans and cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:121816. [PMID: 37182578 DOI: 10.1016/j.envpol.2023.121816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/06/2023] [Accepted: 05/11/2023] [Indexed: 05/16/2023]
Abstract
The carcinogenicity of hexavalent chromium [Cr(VI)] and its compounds has been widely recognized, yet the mechanism of genetic damage is still not fully understood. The ribosomal DNA (rDNA) copy number is recently considered a potential marker of cancer-associated stress. To investigate the roles of rDNA copy number variation (CNV) in DNA damage responses (DDRs) induced by Cr(VI) and the potential mechanism from nucleolar protein HRAS, a cross-sectional study in Cr(Ⅵ)-exposed workers and an in vitro experiment using HeLa cells were conducted. Our results showed increased levels of rDNA CNV, DDRs, and HRAS expression in Cr(VI)-exposed workers. Generalized linear regression analyses showed that Cr(VI) exposure was significantly positively associated with increased levels of rDNA CNV, DDRs, and HRAS expression in Cr(VI)-exposed workers. Moreover, there were pairwise associations between rDNA CNV, DDRs, and HRAS levels. Mediation analyses found that rDNA CNV significantly mediated the association between Cr(VI) exposure and DDRs. The in vitro experiments further confirmed that Cr(VI) treatment induced increased levels of rDNA CNV, DDRs, and HRAS expression in HeLa cells. Cr(VI)-induced rDNA CNV, ATM activation, and apoptosis damage were then strongly enhanced by HRAS depletion with siRNA in vitro, suggesting the important role of HRAS in CNV and DDRs caused by Cr(VI). The combined results of the human and cell line studies indicated that Cr(VI) exposure might enhance rDNA CNV by regulation of HRAS expression, which leads to Cr(VI)-induced genetic damage.
Collapse
Affiliation(s)
- Huadong Xu
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Li Shi
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Lingfang Feng
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Fan Wu
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Junfei Chen
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Yao Qin
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Xiaowen Dong
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Zhaoqiang Jiang
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Yongxin Li
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Hailing Xia
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China
| | - Jianlin Lou
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, 310013, China; School of Medicine, and the First Affiliated Hospital, Huzhou University, Huzhou, Zhejiang, 313000, China.
| |
Collapse
|
11
|
Mascarenhas Dos Santos AC, Julian AT, Liang P, Juárez O, Pombert JF. Telomere-to-Telomere genome assemblies of human-infecting Encephalitozoon species. BMC Genomics 2023; 24:237. [PMID: 37142951 PMCID: PMC10158259 DOI: 10.1186/s12864-023-09331-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Microsporidia are diverse spore forming, fungal-related obligate intracellular pathogens infecting a wide range of hosts. This diversity is reflected at the genome level with sizes varying by an order of magnitude, ranging from less than 3 Mb in Encephalitozoon species (the smallest known in eukaryotes) to more than 50 Mb in Edhazardia spp. As a paradigm of genome reduction in eukaryotes, the small Encephalitozoon genomes have attracted much attention with investigations revealing gene dense, repeat- and intron-poor genomes characterized by a thorough pruning of molecular functions no longer relevant to their obligate intracellular lifestyle. However, because no Encephalitozoon genome has been sequenced from telomere-to-telomere and since no methylation data is available for these species, our understanding of their overall genetic and epigenetic architectures is incomplete. METHODS In this study, we sequenced the complete genomes from telomere-to-telomere of three human-infecting Encephalitozoon spp. -E. intestinalis ATCC 50506, E. hellem ATCC 50604 and E. cuniculi ATCC 50602- using short and long read platforms and leveraged the data generated as part of the sequencing process to investigate the presence of epigenetic markers in these genomes. We also used a mixture of sequence- and structure-based computational approaches, including protein structure prediction, to help identify which Encephalitozoon proteins are involved in telomere maintenance, epigenetic regulation, and heterochromatin formation. RESULTS The Encephalitozoon chromosomes were found capped by TTAGG 5-mer telomeric repeats followed by telomere associated repeat elements (TAREs) flanking hypermethylated ribosomal RNA (rRNA) gene loci featuring 5-methylcytosines (5mC) and 5-hemimethylcytosines (5hmC), themselves followed by lesser methylated subtelomeres and hypomethylated chromosome cores. Strong nucleotide biases were identified between the telomeres/subtelomeres and chromosome cores with significant changes in GC/AT, GT/AC and GA/CT contents. The presence of several genes coding for proteins essential to telomere maintenance, epigenetic regulation, and heterochromatin formation was further confirmed in the Encephalitozoon genomes. CONCLUSION Altogether, our results strongly support the subtelomeres as sites of heterochromatin formation in Encephalitozoon genomes and further suggest that these species might shutdown their energy-consuming ribosomal machinery while dormant as spores by silencing of the rRNA genes using both 5mC/5hmC methylation and facultative heterochromatin formation at these loci.
Collapse
Affiliation(s)
| | | | - Pingdong Liang
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Oscar Juárez
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | | |
Collapse
|
12
|
Lazar-Stefanita L, Luo J, Haase MAB, Zhang W, Boeke JD. Two differentially stable rDNA loci coexist on the same chromosome and form a single nucleolus. Proc Natl Acad Sci U S A 2023; 120:e2219126120. [PMID: 36821584 PMCID: PMC9992848 DOI: 10.1073/pnas.2219126120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/20/2023] [Indexed: 02/24/2023] Open
Abstract
The nucleolus is the most prominent membraneless compartment within the nucleus-dedicated to the metabolism of ribosomal RNA. Nucleoli are composed of hundreds of ribosomal DNA (rDNA) repeated genes that form large chromosomal clusters, whose high recombination rates can cause nucleolar dysfunction and promote genome instability. Intriguingly, the evolving architecture of eukaryotic genomes appears to have favored two strategic rDNA locations-where a single locus per chromosome is situated either near the centromere (CEN) or the telomere. Here, we deployed an innovative genome engineering approach to cut and paste to an ectopic chromosomal location-the ~1.5 mega-base rDNA locus in a single step using CRISPR technology. This "megablock" rDNA engineering was performed in a fused-karyotype strain of Saccharomyces cerevisiae. The strategic repositioning of this locus within the megachromosome allowed experimentally mimicking and monitoring the outcome of an rDNA migratory event, in which twin rDNA loci coexist on the same chromosomal arm. We showed that the twin-rDNA yeast readily adapts, exhibiting wild-type growth and maintaining rRNA homeostasis, and that the twin loci form a single nucleolus throughout the cell cycle. Unexpectedly, the size of each rDNA array appears to depend on its position relative to the CEN, in that the locus that is CEN-distal undergoes size reduction at a higher frequency compared to the CEN-proximal counterpart. Finally, we provided molecular evidence supporting a mechanism called paralogous cis-rDNA interference, which potentially explains why placing two identical repeated arrays on the same chromosome may negatively affect their function and structural stability.
Collapse
Affiliation(s)
- Luciana Lazar-Stefanita
- Institute for Systems Genetics, NYU Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY10016
| | - Jingchuan Luo
- Institute for Systems Genetics, NYU Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY10016
| | - Max A. B. Haase
- Institute for Systems Genetics, NYU Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY10016
- Vilcek Institute of Graduate Biomedical Sciences at NYU School of Medicine, New York, NY10016
| | - Weimin Zhang
- Institute for Systems Genetics, NYU Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY10016
| | - Jef D. Boeke
- Institute for Systems Genetics, NYU Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY10016
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY11201
| |
Collapse
|
13
|
Regulation of ribosomal RNA gene copy number, transcription and nucleolus organization in eukaryotes. Nat Rev Mol Cell Biol 2023; 24:414-429. [PMID: 36732602 DOI: 10.1038/s41580-022-00573-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2022] [Indexed: 02/04/2023]
Abstract
One of the first biological machineries to be created seems to have been the ribosome. Since then, organisms have dedicated great efforts to optimize this apparatus. The ribosomal RNA (rRNA) contained within ribosomes is crucial for protein synthesis and maintenance of cellular function in all known organisms. In eukaryotic cells, rRNA is produced from ribosomal DNA clusters of tandem rRNA genes, whose organization in the nucleolus, maintenance and transcription are strictly regulated to satisfy the substantial demand for rRNA required for ribosome biogenesis. Recent studies have elucidated mechanisms underlying the integrity of ribosomal DNA and regulation of its transcription, including epigenetic mechanisms and a unique recombination and copy-number control system to stably maintain high rRNA gene copy number. In this Review, we disucss how the crucial maintenance of rRNA gene copy number through control of gene amplification and of rRNA production by RNA polymerase I are orchestrated. We also discuss how liquid-liquid phase separation controls the architecture and function of the nucleolus and the relationship between rRNA production, cell senescence and disease.
Collapse
|
14
|
Yan D, Hua L. Nucleolar stress: Friend or foe in cardiac function? Front Cardiovasc Med 2022; 9:1045455. [PMID: 36386352 PMCID: PMC9659567 DOI: 10.3389/fcvm.2022.1045455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 10/17/2022] [Indexed: 03/14/2024] Open
Abstract
Studies in the past decades have uncovered an emerging role of the nucleolus in stress response and human disease progression. The disruption of ribosome biogenesis in the nucleolus causes aberrant nucleolar architecture and function, termed nucleolar stress, to initiate stress-responsive pathways via nucleolar release sequestration of various proteins. While data obtained from both clinical and basic investigations have faithfully demonstrated an involvement of nucleolar stress in the pathogenesis of cardiomyopathy, much remains unclear regarding its precise role in the progression of cardiac diseases. On the one hand, the initiation of nucleolar stress following acute myocardial damage leads to the upregulation of various cardioprotective nucleolar proteins, including nucleostemin (NS), nucleophosmin (NPM) and nucleolin (NCL). As a result, nucleolar stress plays an important role in facilitating the survival and repair of cardiomyocytes. On the other hand, abnormalities in nucleolar architecture and function are correlated with the deterioration of cardiac diseases. Notably, the cardiomyocytes of advanced ischemic and dilated cardiomyopathy display impaired silver-stained nucleolar organiser regions (AgNORs) and enlarged nucleoli, resembling the characteristics of tissue aging. Collectively, nucleolar abnormalities are critically involved in the development of cardiac diseases.
Collapse
Affiliation(s)
- Daliang Yan
- Department of Cardiovascular Surgery, Taizhou People’s Hospital, Taizhou, China
| | - Lu Hua
- Department of Oncology, Taizhou People’s Hospital, Taizhou, China
| |
Collapse
|
15
|
Lagunas-Rangel FA. Ribosomal RNA Transcription Machineries in Intestinal Protozoan Parasites: A Bioinformatic Analysis. Acta Parasitol 2022; 67:1788-1799. [PMID: 36028726 DOI: 10.1007/s11686-022-00612-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/10/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE Ribosome biogenesis is a key process in all living organisms, energetically expensive and tightly regulated. Currently, little is known about the components of the ribosomal RNA (rRNA) transcription machinery that are present in intestinal parasites, such as Giardia duodenalis, Cryptosporidium parvum, and Entamoeba histolytica. Thus, in the present work, an analysis was carried out looking for the components of the rRNA transcription machinery that are conserved in intestinal parasites and if these could be used to design new treatment strategies. METHODS The different components of the rRNA transcription machinery were searched in the studied parasites with the NCBI BLAST tool in the EuPathDB Bioinformatics Resource Center database. The sequences of the RRN3 and POLR1F orthologs were aligned and important regions identified. Subsequently, three-dimensional models were built with different bioinformatic tools and a structural analysis was performed. RESULTS Among the protozoa examined, C. parvum is the parasite with the fewest identifiable components of the rRNA transcription machinery. TBP, RRN3, POLR1A, POLR1B, POLR1C, POLR1D, POLR1F, POLR1H, POLR2E, POLR2F and POLR2H subunits were identified in all species studied. Furthermore, the interaction regions between RRN3 and POLR1F were found to be conserved and could be used to design drugs that inhibit rRNA transcription in the parasites studied. CONCLUSION The inhibition of the rRNA transcription machinery in parasites might be a new therapeutic strategy against these microorganisms.
Collapse
|
16
|
Zhang X, Jia X, Zhong B, Wei L, Li J, Zhang W, Fang H, Li Y, Lu Y, Wang X. Evaluating methylation of human ribosomal DNA at each CpG site reveals its utility for cancer detection using cell-free DNA. Brief Bioinform 2022; 23:6634225. [PMID: 35804466 DOI: 10.1093/bib/bbac278] [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: 04/11/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Ribosomal deoxyribonucleic acid (DNA) (rDNA) repeats are tandemly located on five acrocentric chromosomes with up to hundreds of copies in the human genome. DNA methylation, the most well-studied epigenetic mechanism, has been characterized for most genomic regions across various biological contexts. However, rDNA methylation patterns remain largely unexplored due to the repetitive structure. In this study, we designed a specific mapping strategy to investigate rDNA methylation patterns at each CpG site across various physiological and pathological processes. We found that CpG sites on rDNA could be categorized into two types. One is within or adjacent to transcribed regions; the other is distal to transcribed regions. The former shows highly variable methylation levels across samples, while the latter shows stable high methylation levels in normal tissues but severe hypomethylation in tumors. We further showed that rDNA methylation profiles in plasma cell-free DNA could be used as a biomarker for cancer detection. It shows good performances on public datasets, including colorectal cancer [area under the curve (AUC) = 0.85], lung cancer (AUC = 0.84), hepatocellular carcinoma (AUC = 0.91) and in-house generated hepatocellular carcinoma dataset (AUC = 0.96) even at low genome coverage (<1×). Taken together, these findings broaden our understanding of rDNA regulation and suggest the potential utility of rDNA methylation features as disease biomarkers.
Collapse
Affiliation(s)
- Xianglin Zhang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Xiaodong Jia
- Senior Department of Oncology, Fifth Medical Center of PLA General Hospital, Beijing 100039, China
| | - Bixi Zhong
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Lei Wei
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Jiaqi Li
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Wei Zhang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Huan Fang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Yanda Li
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Yinying Lu
- Comprehensive Liver Cancer Center, Fifth Medical Center of PLA General Hospital, Beijing 100039, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.,Guangdong Key Laboratory of Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Xiaowo Wang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| |
Collapse
|
17
|
DNA Methylation Malleability and Dysregulation in Cancer Progression: Understanding the Role of PARP1. Biomolecules 2022; 12:biom12030417. [PMID: 35327610 PMCID: PMC8946700 DOI: 10.3390/biom12030417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/28/2022] [Accepted: 03/04/2022] [Indexed: 02/05/2023] Open
Abstract
Mammalian genomic DNA methylation represents a key epigenetic modification and its dynamic regulation that fine-tunes the gene expression of multiple pathways during development. It maintains the gene expression of one generation of cells; particularly, the mitotic inheritance of gene-expression patterns makes it the key governing mechanism of epigenetic change to the next generation of cells. Convincing evidence from recent discoveries suggests that the dynamic regulation of DNA methylation is accomplished by the enzymatic action of TET dioxygenase, which oxidizes the methyl group of cytosine and activates transcription. As a result of aberrant DNA modifications, genes are improperly activated or inhibited in the inappropriate cellular context, contributing to a plethora of inheritable diseases, including cancer. We outline recent advancements in understanding how DNA modifications contribute to tumor suppressor gene silencing or oncogenic-gene stimulation, as well as dysregulation of DNA methylation in cancer progression. In addition, we emphasize the function of PARP1 enzymatic activity or inhibition in the maintenance of DNA methylation dysregulation. In the context of cancer remediation, the impact of DNA methylation and PARP1 pharmacological inhibitors, and their relevance as a combination therapy are highlighted.
Collapse
|
18
|
Oh J, Yeom S, Park J, Lee JS. The regional sequestration of heterochromatin structural proteins is critical to form and maintain silent chromatin. Epigenetics Chromatin 2022; 15:5. [PMID: 35101096 PMCID: PMC8805269 DOI: 10.1186/s13072-022-00435-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/06/2022] [Indexed: 12/20/2022] Open
Abstract
Budding yeast Saccharomyces cerevisiae and fission yeast Schizosaccharomyces pombe are good models for heterochromatin study. In S. pombe, H3K9 methylation and Swi6, an ortholog of mammalian HP1, lead to heterochromatin formation. However, S. cerevisiae does not have known epigenetic silencing markers and instead has Sir proteins to regulate silent chromatin formation. Although S. cerevisiae and S. pombe form and maintain heterochromatin via mechanisms that appear to be fundamentally different, they share important common features in the heterochromatin structural proteins. Heterochromatin loci are localized at the nuclear periphery by binding to perinuclear membrane proteins, thereby producing distinct heterochromatin foci, which sequester heterochromatin structural proteins. In this review, we discuss the nuclear peripheral anchoring of heterochromatin foci and its functional relevance to heterochromatin formation and maintenance.
Collapse
Affiliation(s)
- Junsoo Oh
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea
| | - Soojin Yeom
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea
| | - Jiyeon Park
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea
| | - Jung-Shin Lee
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea.
| |
Collapse
|
19
|
Fefelova EA, Pleshakova IM, Mikhaleva EA, Pirogov SA, Poltorachenko V, Abramov Y, Romashin D, Shatskikh A, Blokh R, Gvozdev V, Klenov M. Impaired function of rDNA transcription initiation machinery leads to derepression of ribosomal genes with insertions of R2 retrotransposon. Nucleic Acids Res 2022; 50:867-884. [PMID: 35037046 PMCID: PMC8789037 DOI: 10.1093/nar/gkab1276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/21/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic genomes harbor hundreds of rRNA genes, many of which are transcriptionally silent. However, little is known about selective regulation of individual rDNA units. In Drosophila melanogaster, some rDNA repeats contain insertions of the R2 retrotransposon, which is capable to be transcribed only as part of pre-rRNA molecules. rDNA units with R2 insertions are usually inactivated, although R2 expression may be beneficial in cells with decreased rDNA copy number. Here we found that R2-inserted rDNA units are enriched with HP1a and H3K9me3 repressive mark, whereas disruption of the heterochromatin components slightly affects their silencing in ovarian germ cells. Surprisingly, we observed a dramatic upregulation of R2-inserted rRNA genes in ovaries lacking Udd (Under-developed) or other subunits (TAF1b and TAF1c-like) of the SL1-like complex, which is homologues to mammalian Selective factor 1 (SL1) involved in rDNA transcription initiation. Derepression of rRNA genes with R2 insertions was accompanied by a reduction of H3K9me3 and HP1a enrichment. We suggest that the impairment of the SL1-like complex affects a mechanism of selective activation of intact rDNA units which competes with heterochromatin formation. We also propose that R2 derepression may serve as an adaptive response to compromised rRNA synthesis.
Collapse
Affiliation(s)
- Elena A Fefelova
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena 91125, USA
| | - Irina M Pleshakova
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Laboratory for Neurobiology of Memory, P.K. Anokhin Institute of Normal Physiology, Moscow 125315, Russia
| | - Elena A Mikhaleva
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Sergei A Pirogov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Valentin A Poltorachenko
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Yuri A Abramov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Daniil D Romashin
- Laboratory of Precision Biosystems, V. N. Orekhovich Institute of Biomedical Chemistry, 10 Pogodinskaya St., Moscow 119121, Russia
| | - Aleksei S Shatskikh
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Roman S Blokh
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Department of Functional Genomics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova Street, Moscow 119334, Russia
| | - Vladimir A Gvozdev
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Mikhail S Klenov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| |
Collapse
|
20
|
Yeom S, Oh J, Lee JS. Spreading-dependent or independent Sir2-mediated gene silencing in budding yeast. Genes Genomics 2022; 44:359-367. [PMID: 35034281 DOI: 10.1007/s13258-021-01203-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 12/02/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND In the budding yeast Saccharomyces cerevisiae, a silent chromatin structure is formed at three distinct loci, including telomeres, rDNA, and mating-type loci, which silence the expression of genes within their structures. Sir2 is the only common factor, regulating the three silent chromatin regions. S. cerevisiae has 32 telomeres, but studies on gene silencing in budding yeast have been performed using some reporter genes, artificially inserted in the telomeric regions. Therefore, insights into the global landscape of Sir-dependent silencing of genes within the silent chromatin regions are required. OBJECTIVE This study aimed to obtain global insights into Sir2-dependent gene silencing on all silent chromatin regions in budding yeast. METHODS RNA-sequencing was performed to identify genes that are silenced by Sir2. By comparing with the chromatin immunoprecipitation-sequencing (ChIP-seq) of Sir2 in the wild-type strain, we confirmed Sir2-regulated genes. RESULTS Using Sir2 ChIP-seq data, we identified that the Sir2 binding domain length caused by Sir2 spreading from the chromosomal end is different in each telomere in budding yeast. Expression of most subtelomeric genes increased in the ∆sir2 strain. Some Sir2-regulated subtelomeric genes were positioned within the telomeric Sir2-binding domain, while the others were outside the Sir2-binding domain. In addition, Sir2 was bound to the mating-type loci and rDNA region, and gene expression increased in the ∆sir2 strain. CONCLUSION We concluded that S. cerevisiae has two modes of Sir2-mediated gene silencing: one is dependent on chromatin binding and spreading of Sir2, and the other is independent of spreading of Sir2.
Collapse
Affiliation(s)
- Soojin Yeom
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea
| | - Junsoo Oh
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea
| | - Jung-Shin Lee
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Kangwondeahak-gil, Chuncheon, 24341, Republic of Korea.
| |
Collapse
|
21
|
Schächner C, Merkl PE, Pilsl M, Schwank K, Hergert K, Kruse S, Milkereit P, Tschochner H, Griesenbeck J. Establishment and Maintenance of Open Ribosomal RNA Gene Chromatin States in Eukaryotes. Methods Mol Biol 2022; 2533:25-38. [PMID: 35796980 PMCID: PMC9761505 DOI: 10.1007/978-1-0716-2501-9_2] [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: 06/15/2023]
Abstract
In growing eukaryotic cells, nuclear ribosomal (r)RNA synthesis by RNA polymerase (RNAP) I accounts for the vast majority of cellular transcription. This high output is achieved by the presence of multiple copies of rRNA genes in eukaryotic genomes transcribed at a high rate. In contrast to most of the other transcribed genomic loci, actively transcribed rRNA genes are largely devoid of nucleosomes adapting a characteristic "open" chromatin state, whereas a significant fraction of rRNA genes resides in a transcriptionally inactive nucleosomal "closed" chromatin state. Here, we review our current knowledge about the nature of open rRNA gene chromatin and discuss how this state may be established.
Collapse
Affiliation(s)
- Christopher Schächner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Philipp E Merkl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
- TUM ForTe, Technische Universität München, Munich, Germany
| | - Michael Pilsl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Katrin Schwank
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Kristin Hergert
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Sebastian Kruse
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Philipp Milkereit
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Herbert Tschochner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Joachim Griesenbeck
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| |
Collapse
|
22
|
Kasselimi E, Pefani DE, Taraviras S, Lygerou Z. Ribosomal DNA and the nucleolus at the heart of aging. Trends Biochem Sci 2022; 47:328-341. [DOI: 10.1016/j.tibs.2021.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/15/2022]
|
23
|
Nhim S, Gimenez S, Nait-Saidi R, Severac D, Nam K, d'Alençon E, Nègre N. H3K9me2 genome-wide distribution in the holocentric insect Spodoptera frugiperda (Lepidoptera: Noctuidae). Genomics 2021; 114:384-397. [PMID: 34971718 DOI: 10.1016/j.ygeno.2021.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/02/2021] [Accepted: 12/15/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND Eukaryotic genomes are packaged by Histone proteins in a structure called chromatin. There are different chromatin types. Euchromatin is typically associated with decondensed, transcriptionally active regions and heterochromatin to more condensed regions of the chromosomes. Methylation of Lysine 9 of Histone H3 (H3K9me) is a conserved biochemical marker of heterochromatin. In many organisms, heterochromatin is usually localized at telomeric as well as pericentromeric regions but can also be found at interstitial chromosomal loci. This distribution may vary in different species depending on their general chromosomal organization. Holocentric species such as Spodoptera frugiperda (Lepidoptera: Noctuidae) possess dispersed centromeres instead of a monocentric one and thus no observable pericentromeric compartment. To identify the localization of heterochromatin in such species we performed ChIP-Seq experiments and analyzed the distribution of the heterochromatin marker H3K9me2 in the Sf9 cell line and whole 4th instar larvae (L4) in relation to RNA-Seq data. RESULTS In both samples we measured an enrichment of H3K9me2 at the (sub) telomeres, rDNA loci, and satellite DNA sequences, which could represent dispersed centromeric regions. We also observed that density of H3K9me2 is positively correlated with transposable elements and protein-coding genes. But contrary to most model organisms, H3K9me2 density is not correlated with transcriptional repression. CONCLUSION This is the first genome-wide ChIP-Seq analysis conducted in S. frugiperda for H3K9me2. Compared to model organisms, this mark is found in expected chromosomal compartments such as rDNA and telomeres. However, it is also localized at numerous dispersed regions, instead of the well described large pericentromeric domains, indicating that H3K9me2 might not represent a classical heterochromatin marker in Lepidoptera. (242 words).
Collapse
Affiliation(s)
- Sandra Nhim
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | | | - Dany Severac
- MGX, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Kiwoong Nam
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | - Nicolas Nègre
- DGIMI, Univ Montpellier, INRAE, Montpellier, France.
| |
Collapse
|
24
|
Haig D. Concerted evolution of ribosomal DNA: Somatic peace amid germinal strife: Intranuclear and cellular selection maintain the quality of rRNA. Bioessays 2021; 43:e2100179. [PMID: 34704616 DOI: 10.1002/bies.202100179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/12/2021] [Indexed: 11/10/2022]
Abstract
Most eukaryotes possess many copies of rDNA. Organismal selection alone cannot maintain rRNA function because the effects of mutations in one rDNA are diluted by the presence of many other rDNAs. rRNA quality is maintained by processes that increase homogeneity of rRNA within, and heterogeneity among, germ cells thereby increasing the effectiveness of cellular selection on ribosomal function. A successful rDNA repeat will possess adaptations for spreading within tandem arrays by intranuclear selection. These adaptations reside in the non-coding regions of rDNA. Single-copy genes are predicted to manage processes of intranuclear and cellular selection in the germline to maintain the quality of rRNA expressed in somatic cells of future generations.
Collapse
Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| |
Collapse
|
25
|
Luttermann T, Rückert C, Wibberg D, Busche T, Schwarzhans JP, Friehs K, Kalinowski J. Establishment of a near-contiguous genome sequence of the citric acid producing yeast Yarrowia lipolytica DSM 3286 with resolution of rDNA clusters and telomeres. NAR Genom Bioinform 2021; 3:lqab085. [PMID: 34661101 PMCID: PMC8515841 DOI: 10.1093/nargab/lqab085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 09/01/2021] [Accepted: 10/13/2021] [Indexed: 11/29/2022] Open
Abstract
Yarrowia lipolytica is an oleaginous yeast that is particularly suitable for the sustainable production of secondary metabolites. The genome of this yeast is characterized by its relatively large size and its high number of different rDNA clusters located in its telomeric regions. However, due to the presence of long repetitive elements in the sub-telomeric regions, rDNA clusters and telomeres are missing in current genome assemblies of Y. lipolytica. Here, we present the near-contiguous genome sequence of the biotechnologically relevant strain DSM 3286. We employed a hybrid assembly strategy combining Illumina and nanopore sequencing reads to integrate all six rDNA clusters as well as telomeric repeats into the genome sequence. By fine-tuning of DNA isolation and library preparation protocols, we were able to create ultra-long reads that not only contained multiples of mitochondrial genomes but also shed light on the inter- and intra-chromosomal diversity of rDNA cluster types. We show that there are ten different rDNA units present in this strain that additionally appear in a predefined order in a cluster. Based on single reads, we also demonstrate that the number of rDNA repeats in a specific cluster varies from cell to cell within a population.
Collapse
Affiliation(s)
- Tobias Luttermann
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Christian Rückert
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Daniel Wibberg
- Genome Research of Industrial Microorganisms, Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Tobias Busche
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | | | - Karl Friehs
- Fermentation Engineering, Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| |
Collapse
|
26
|
Datta A, Pollock KJ, Kormuth KA, Brosh RM. G-Quadruplex Assembly by Ribosomal DNA: Emerging Roles in Disease Pathogenesis and Cancer Biology. Cytogenet Genome Res 2021; 161:285-296. [PMID: 34469893 DOI: 10.1159/000516394] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/03/2021] [Indexed: 12/15/2022] Open
Abstract
Unique repetitive elements of the eukaryotic genome can be problematic for cellular DNA replication and transcription and pose a source of genomic instability. Human ribosomal DNA (rDNA) exists as repeating units clustered together on several chromosomes. Understanding the molecular mechanisms whereby rDNA interferes with normal genome homeostasis is the subject of this review. We discuss the instability of rDNA as a driver of senescence and the important roles of helicases to suppress its deleterious effects. The propensity of rDNA that is rich in guanine bases to form G-quadruplexes (G4) is discussed and evaluated in disease pathogenesis. Targeting G4 in the ribosomes and other chromosomal loci may represent a useful synthetic lethal approach to combating cancer.
Collapse
Affiliation(s)
- Arindam Datta
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Kevin J Pollock
- Department of Biology, Bethany College, Bethany, West Virginia, USA
| | - Karen A Kormuth
- Department of Biology, Bethany College, Bethany, West Virginia, USA
| | - Robert M Brosh
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA
| |
Collapse
|
27
|
Lagunas-Rangel FA, Bazán-Tejeda ML, Bermúdez-Cruz RM. Ribosomal DNA in the protozoan parasite Giardia duodenalis has a differential chromatin distribution and epigenetic markings across the subunits. Acta Trop 2021; 217:105872. [PMID: 33639100 DOI: 10.1016/j.actatropica.2021.105872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/12/2021] [Accepted: 02/22/2021] [Indexed: 02/08/2023]
Abstract
Giardia duodenalis is a parasite that causes a large number of diarrheal diseases around the world. It is noteworthy that in a large number of processes, Giardia requires fewer components than other eukaryotes, even without some organelles such as mitochondria and peroxisomes. Despite this, core histones are known to exist in Giardia and epigenetic marks have been found on them, suggesting that they somehow control the expression of certain genes. The regulation of the expression of ribosomal DNA (rDNA) is essential, since it is required to maintain adequate levels of ribosomes and, given the nature of tandem repeat, it is a feasible area to create genomic instability. In Giardia, it is not known how this process occurs, but as in other eukaryotes, it is suggested through various epigenetic mechanisms. Thus, in the present work we seek to identify how chromatin is distributed through the Giardia rDNA and if there were histone marks that could control its expression.
Collapse
|
28
|
Pérez RF, Tejedor JR, Santamarina-Ojeda P, Martínez VL, Urdinguio RG, Villamañán L, Candiota AP, Sarró NMV, Barradas M, Fernandez-Marcos PJ, Serrano M, Fernández AF, Fraga MF. Conservation of Aging and Cancer Epigenetic Signatures across Human and Mouse. Mol Biol Evol 2021; 38:3415-3435. [PMID: 33871658 PMCID: PMC8321527 DOI: 10.1093/molbev/msab112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aging and cancer are two interrelated processes, with aging being a major risk factor for the development of cancer. Parallel epigenetic alterations have been described for both, although differences, especially within the DNA hypomethylation scenario, have also been recently reported. Although many of these observations arise from the use of mouse models, there is a lack of systematic comparisons of human and mouse epigenetic patterns in the context of disease. However, such comparisons are significant as they allow to establish the extent to which some of the observed similarities or differences arise from pre-existing species-specific epigenetic traits. Here, we have used reduced representation bisulfite sequencing to profile the brain methylomes of young and old, tumoral and nontumoral brain samples from human and mouse. We first characterized the baseline epigenomic patterns of the species and subsequently focused on the DNA methylation alterations associated with cancer and aging. Next, we described the functional genomic and epigenomic context associated with the alterations, and finally, we integrated our data to study interspecies DNA methylation levels at orthologous CpG sites. Globally, we found considerable differences between the characteristics of DNA methylation alterations in cancer and aging in both species. Moreover, we describe robust evidence for the conservation of the specific cancer and aging epigenomic signatures in human and mouse. Our observations point toward the preservation of the functional consequences of these alterations at multiple levels of genomic regulation. Finally, our analyses reveal a role for the genomic context in explaining disease- and species-specific epigenetic traits.
Collapse
Affiliation(s)
- Raúl F Pérez
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Juan Ramón Tejedor
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Pablo Santamarina-Ojeda
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Virginia López Martínez
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Rocío G Urdinguio
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Lucía Villamañán
- Unitat de Bioquímica de Biociències, Departament de Bioquímica i Biologia Molecular, Edifici Cs, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Ana Paula Candiota
- Unitat de Bioquímica de Biociències, Departament de Bioquímica i Biologia Molecular, Edifici Cs, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - N Mí Vidal Sarró
- Servicio Anatomía Patológica, Hospital Universitari de Bellvitge-IDIBELL, Hospitalet de Llobregat, Spain
| | - Marta Barradas
- Metabolic Syndrome Group-BIOPROMET, Madrid Institute for Advanced Studies-IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Pablo Jose Fernandez-Marcos
- Metabolic Syndrome Group-BIOPROMET, Madrid Institute for Advanced Studies-IMDEA Food, CEI UAM+CSIC, Madrid, Spain
| | - Manuel Serrano
- Tumour Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,Cellular Plasticity and Disease Group, Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Agusín F Fernández
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| | - Mario F Fraga
- Cancer Epigenetics and Nanomedicine Laboratory, Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo, Oviedo, Spain.,Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.,Health Research Institute of Asturias (ISPA), University of Oviedo, Oviedo, Spain.,Department of Organisms and Systems Biology (B.O.S.), University of Oviedo, Oviedo, Spain.,Rare Diseases CIBER (CIBERER) of the Carlos III Health Institute (ISCIII), Madrid, Spain
| |
Collapse
|
29
|
Lim S, Ahn H, Duan R, Liu Y, Ryu HY, Ahn SH. The Spt7 subunit of the SAGA complex is required for the regulation of lifespan in both dividing and nondividing yeast cells. Mech Ageing Dev 2021; 196:111480. [PMID: 33831401 DOI: 10.1016/j.mad.2021.111480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/23/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
Spt7 belongs to the suppressor of Ty (SPT) module of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex and is known as the yeast ortholog of human STAF65γ. Spt7 lacks intrinsic enzymatic activity but is responsible for the integrity and proper assembly of the SAGA complex. Here, we determined the role of the SAGA Spt7 subunit in cellular aging. We found that Spt7 was indispensable for a normal lifespan in both dividing and nondividing yeast cells. In the quiescent state of cells, Spt7 was required for the control of overall mRNA levels. In mitotically active cells, deletion of the SPT module had little effect on the recombination rate within heterochromatic ribosomal DNA (rDNA) loci, but loss of Spt7 profoundly elevated the plasmid-based DNA recombination frequency. Consistently, loss of Spt7 increased spontaneous Rad52 foci by approximately two-fold upon entry into S phase. These results provide evidence that Spt7 contributes to the regulation of the normal replicative lifespan (RLS) and chronological lifespan (CLS), possibly by controlling the DNA recombination rate and overall mRNA expression. We propose that the regulation of SAGA complex integrity by Spt7 might be involved in the conserved regulatory pathway for lifespan regulation in eukaryotes.
Collapse
Affiliation(s)
- Suji Lim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, Ansan 15588, Republic of Korea
| | - Hyojeong Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, Ansan 15588, Republic of Korea
| | - Ruxin Duan
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, Ansan 15588, Republic of Korea
| | - Yan Liu
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, Ansan 15588, Republic of Korea
| | - Hong-Yeoul Ryu
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of National Sciences, Kyungpook National University, Daegu 41566, Republic of Korea.
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, Ansan 15588, Republic of Korea.
| |
Collapse
|
30
|
Edskes HK, Stroobant EE, DeWilde MP, Bezsonov EE, Wickner RB. Proteasome Control of [URE3] Prion Propagation by Degradation of Anti-Prion Proteins Cur1 and Btn2 in Saccharomyces cerevisiae. Genetics 2021; 218:6179111. [PMID: 33742650 DOI: 10.1093/genetics/iyab037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/27/2021] [Indexed: 01/16/2023] Open
Abstract
[URE3] is a prion of the nitrogen catabolism controller, Ure2p, and [PSI+] is a prion of the translation termination factor Sup35p in S. cerevisiae. Btn2p cures [URE3] by sequestration of Ure2p amyloid filaments. Cur1p, paralogous to Btn2p, also cures [URE3], but by a different (unknown) mechanism. We find that an array of mutations impairing proteasome assembly or MG132 inhibition of proteasome activity result in loss of [URE3]. In proportion to their prion-curing effects, each mutation affecting proteasomes elevates the cellular concentration of the anti-prion proteins Btn2 and Cur1. Of >4,600 proteins detected by SILAC, Btn2p was easily the most overexpressed in a pre9Δ (α3 core subunit) strain. Indeed, deletion of BTN2 and CUR1 prevents the prion-curing effects of proteasome impairment. Surprisingly, the 15 most unstable yeast proteins are not increased in pre9Δ cells suggesting altered proteasome specificity rather than simple inactivation. Hsp42, a chaperone that cooperates with Btn2 and Cur1 in curing [URE3], is also necessary for the curing produced by proteasome defects, although Hsp42p levels are not substantially altered by a proteasome defect. We find that pre9Δ and proteasome chaperone mutants that most efficiently lose [URE3], do not destabilize [PSI+] or alter cellular levels of Sup35p. A tof2 mutation or deletion likewise destabilizes [URE3], and elevates Btn2p, suggesting that Tof2p deficiency inactivates proteasomes. We suggest that when proteasomes are saturated with denatured/misfolded proteins, their reduced degradation of Btn2p and Cur1p automatically upregulates these aggregate-handling systems to assist in the clean-up.
Collapse
Affiliation(s)
- Herman K Edskes
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Emily E Stroobant
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Morgan P DeWilde
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Evgeny E Bezsonov
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| |
Collapse
|
31
|
Cardoso da Silva R, Vader G. Getting there: understanding the chromosomal recruitment of the AAA+ ATPase Pch2/TRIP13 during meiosis. Curr Genet 2021; 67:553-565. [PMID: 33712914 PMCID: PMC8254700 DOI: 10.1007/s00294-021-01166-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 12/21/2022]
Abstract
The generally conserved AAA+ ATPase Pch2/TRIP13 is involved in diverse aspects of meiosis, such as prophase checkpoint function, DNA break regulation, and meiotic recombination. The controlled recruitment of Pch2 to meiotic chromosomes allows it to use its ATPase activity to influence HORMA protein-dependent signaling. Because of the connection between Pch2 chromosomal recruitment and its functional roles in meiosis, it is important to reveal the molecular details that govern Pch2 localization. Here, we review the current understanding of the different factors that control the recruitment of Pch2 to meiotic chromosomes, with a focus on research performed in budding yeast. During meiosis in this organism, Pch2 is enriched within the nucleolus, where it likely associates with the specialized chromatin of the ribosomal (r)DNA. Pch2 is also found on non-rDNA euchromatin, where its recruitment is contingent on Zip1, a component of the synaptonemal complex (SC) that assembles between homologous chromosomes. We discuss recent findings connecting the recruitment of Pch2 with its association with the Origin Recognition Complex (ORC) and reliance on RNA Polymerase II-dependent transcription. In total, we provide a comprehensive overview of the pathways that control the chromosomal association of an important meiotic regulator.
Collapse
Affiliation(s)
- Richard Cardoso da Silva
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany. .,Department of Molecular Mechanisms of Disease, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
| | - Gerben Vader
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany. .,Department of Clinical Genetics, Section of Oncogenetics, Cancer Center Amsterdam, De Boelelaan 1118, 1081 HV, Amsterdam, The Netherlands.
| |
Collapse
|
32
|
Lagunas-Rangel FA, Yee J, Bazán-Tejeda ML, García-Villa E, Bermúdez-Cruz RM. Sirtuin GdSir2.4 participates in the regulation of rRNA transcription in the Giardia duodenalis parasite. Mol Microbiol 2021; 115:1039-1053. [PMID: 33665906 DOI: 10.1111/mmi.14710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 01/09/2023]
Abstract
Giardia duodenalis is a parasite of great medical interest due to the number of infections it causes worldwide each year. Although research on epigenetic mechanisms in this protist has only begun recently, epigenetic regulation has already been shown to have important roles in encystation, antigenic variation, and resistance to antibiotics in Giardia. In this work, we show that a Giardia ortholog of Sir2, GdSir2.4, is involved in the silencing of rRNA expression. Our results demonstrate that GdSir2.4 localizes to the nucleolus, and its binding to the intergenic spacer region of the rDNA is associated with the deacetylation of the chromatin in this region. Given the importance of the regulation of rRNA expression to maintain adequate levels of ribosomes and genomic stability within the cells, GdSir2.4 can be considered a target to create new therapeutic agents against this parasite.
Collapse
Affiliation(s)
- Francisco Alejandro Lagunas-Rangel
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
| | - Janet Yee
- Department of Biology, Biochemistry and Molecular Biology Program, Trent University, Peterborough, ON, Canada
| | - María Luisa Bazán-Tejeda
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
| | - Enrique García-Villa
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
| | - Rosa María Bermúdez-Cruz
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
| |
Collapse
|
33
|
Hong S, Huh WK. Loss of Smi1, a protein involved in cell wall synthesis, extends replicative life span by enhancing rDNA stability in Saccharomyces cerevisiae. J Biol Chem 2021; 296:100258. [PMID: 33837734 PMCID: PMC7948926 DOI: 10.1016/j.jbc.2021.100258] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 11/17/2022] Open
Abstract
In Saccharomyces cerevisiae, replicative life span (RLS) is primarily affected by the stability of ribosomal DNA (rDNA). The stability of the highly repetitive rDNA array is maintained through transcriptional silencing by the NAD+-dependent histone deacetylase Sir2. Recently, the loss of Smi1, a protein of unknown molecular function that has been proposed to be involved in cell wall synthesis, has been demonstrated to extend RLS in S. cerevisiae, but the mechanism by which Smi1 regulates RLS has not been elucidated. In this study, we determined that the loss of Smi1 extends RLS in a Sir2-dependent manner. We observed that the smi1Δ mutation enhances transcriptional silencing at the rDNA locus and promotes rDNA stability. In the absence of Smi1, the stress-responsive transcription factor Msn2 translocates from the cytoplasm to the nucleus, and nuclear-accumulated Msn2 stimulates the expression of nicotinamidase Pnc1, which serves as an activator of Sir2. In addition, we observed that the MAP kinase Hog1 is activated in smi1Δ cells and that the activation of Hog1 induces the translocation of Msn2 into the nucleus. Taken together, our findings suggest that the loss of Smi1 leads to the nuclear accumulation of Msn2 and stimulates the expression of Pnc1, thereby enhancing Sir2-mediated rDNA stability and extending RLS in S. cerevisiae.
Collapse
Affiliation(s)
- Sujin Hong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
| |
Collapse
|
34
|
Wang S, Wong CC, Zhang Y, Huang J, Li C, Zhai J, Wang G, Wei H, Zhang X, He HH, Yu J. ZNF545 loss promotes ribosome biogenesis and protein translation to initiate colorectal tumorigenesis in mice. Oncogene 2021; 40:6590-6600. [PMID: 34615997 PMCID: PMC8639438 DOI: 10.1038/s41388-021-01938-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 06/21/2021] [Accepted: 07/01/2021] [Indexed: 11/25/2022]
Abstract
Ribosome biogenesis plays a pivotal role in tumorigenesis by supporting robust protein translation. We investigate the functional and molecular mechanism of Zinc finger protein 545 (ZNF545), a transcriptional repressor for ribosomal RNA (rRNA), in colorectal cancer (CRC). ZNF545 was silenced in CRC compared to adjacent normal tissues (P < 0.0001), implying a tumor-suppressive role. Colon-specific Znf545 knockout in mice accelerated CRC in ApcMin/+ and azoxymethane/dextran sulfate sodium-induced CRC. Mechanistically, we demonstrated that ZNF545 uses its two zinc finger clusters to bind to minimal rDNA promoter, where it assembled transcriptional repressor complex by interacting with KAP1. Znf545 deletion in mouse embryonic fibroblasts not only increased rRNA transcription rate and the nucleolar size and number but also altered the nucleolar composition and architecture with an increased number of fibrillar centers surrounded by net-like dense fibrillar components. Consequently, Znf545 deletion promoted the gene expression of translation machinery, protein translation, and cell growth. Consistent with its tumor-suppressive role, ZNF545 overexpression in CRC cells induced growth arrest and apoptosis. Finally, administration of rRNA synthesis inhibitor, CX-5461, inhibited CRC development in Znf545Δ/ΔApcMin/+ mice. In conclusion, ZNF545 suppresses CRC through repressing rRNA transcription and protein translation. Targeting rRNA biosynthesis in ZNF545-silenced tumors is a potential therapeutic strategy for CRC.
Collapse
Affiliation(s)
- Shiyan Wang
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Chun Wong
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Yanquan Zhang
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Junzhe Huang
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Chuangen Li
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Jianning Zhai
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Guoping Wang
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Hong Wei
- grid.12981.330000 0001 2360 039XPrecision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xueji Zhang
- grid.263488.30000 0001 0472 9649School of Biomedical Engineering, Health Science Centre, Shenzhen University, Shenzhen, China
| | - Housheng Hansen He
- grid.17063.330000 0001 2157 2938Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Ontario, Canada
| | - Jun Yu
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
35
|
Chu W, Zhang X, Qi L, Fu Y, Wang P, Zhao W, Du J, Zhang J, Zhan J, Wang Y, Zhu WG, Yu Y, Zhang H. The EZH2-PHACTR2-AS1-Ribosome Axis induces Genomic Instability and Promotes Growth and Metastasis in Breast Cancer. Cancer Res 2020; 80:2737-2750. [PMID: 32312833 DOI: 10.1158/0008-5472.can-19-3326] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/21/2020] [Accepted: 04/15/2020] [Indexed: 11/16/2022]
Abstract
Aberrant activation of histone methyltransferase EZH2 and ribosome synthesis strongly associate with cancer development and progression. We previously found that EZH2 regulates RNA polymerase III-transcribed 5S ribosomal RNA gene transcription. However, whether EZH2 regulates ribosome synthesis is still unknown. Here, we report that EZH2 promotes ribosome synthesis by targeting and silencing a long noncoding RNA PHACTR2-AS1. PHACTR2-AS1 directly bound ribosome DNA genes and recruited histone methyltransferase SUV39H1, which in turn triggered H3K9 methylation of these genes. Depletion of PHACTR2-AS1 resulted in hyperactivation of ribosome synthesis and instability of ribosomal DNA, which promoted cancer cell proliferation and metastasis. Administration of PHACTR2-AS1-30nt-RNA, which binds to SUV39H1, effectively inhibited breast cancer growth and lung metastasis in mice. PHACTR2-AS1 was downregulated in breast cancer patients, where lower PHACTR2-AS1 expression promoted breast cancer development and correlated with poor patient outcome. Taken together, we demonstrate that PHACTR2-AS1 maintains a H3K9 methylation-marked silent state of ribosomal DNA genes, comprising a regulatory axis that controls breast cancer growth and metastasis. SIGNIFICANCE: These findings reveal that EZH2 mediates ribosomal DNA stability via silencing of PHACTR2-AS1, representing a potential therapeutic target to control breast cancer growth and metastasis.
Collapse
Affiliation(s)
- Wenhui Chu
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Xi Zhang
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Lihua Qi
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Yenan Fu
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Peng Wang
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Wei Zhao
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Juan Du
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Jing Zhang
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Jun Zhan
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Yunling Wang
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China
| | - Wei-Guo Zhu
- Guangdong Key Laboratory of Genome Instability and Human Disease, Shenzhen University Carson Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen, China
| | - Yu Yu
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China.
| | - Hongquan Zhang
- Department of Human Anatomy, Histology and Embryology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, China.
| |
Collapse
|
36
|
Existence, Transition, and Propagation of Intermediate Silencing States in Ribosomal DNA. Mol Cell Biol 2019; 39:MCB.00146-19. [PMID: 31527077 DOI: 10.1128/mcb.00146-19] [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: 03/28/2019] [Accepted: 09/10/2019] [Indexed: 11/20/2022] Open
Abstract
The MET3 promoter (MET3pr) inserted into the silenced chromosome in budding yeast can overcome Sir2-dependent silencing upon induction and activate transcription in every single cell among a population. Despite the fact that MET3pr is turned on in all the cells, its activity still shows very high cell-to-cell variability. To understand the nature of such "gene expression noise," we followed the dynamics of the MET3pr-GFP expression inserted into ribosomal DNA (rDNA) using time-lapse microscopy. We found that the noisy "on" state is comprised of multiple substable states with discrete expression levels. These intermediate states stochastically transition between each other, with "up" transitions among different activated states occurring exclusively near the mitotic exit and "down" transitions occurring throughout the rest of the cell cycle. Such cell cycle dependence likely reflects the dynamic activity of the rDNA-specific RENT complex, as MET3pr-GFP expression in a telomeric locus does not have the same cell cycle dependence. The MET3pr-GFP expression in rDNA is highly correlated in mother and daughter cells after cell division, indicating that the silenced state in the mother cell is inherited in daughter cells. These states are disrupted by a brief repression and reset upon a second activation. Potential mechanisms behind these observations are further discussed.
Collapse
|
37
|
Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment. Neural Plast 2019; 2019:4383258. [PMID: 31827497 PMCID: PMC6885846 DOI: 10.1155/2019/4383258] [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: 03/21/2019] [Revised: 09/11/2019] [Accepted: 10/01/2019] [Indexed: 11/21/2022] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear protein that regulates gene expression through poly(ADP)-ribosylation, resulting in the loosening of chromatin structure. PARP-1 enzymatic activity has been shown to be necessary for the expression of several genes required for memory formation and consolidation. Previously, we showed that nucleolar PARP-1 is significantly decreased in hippocampal pyramidal cells in Alzheimer's disease (AD). We proposed that the displacement of PARP-1 from the nucleolus results in downregulation of new rRNA expression and ribosome biogenesis, leading to cognitive impairment. To further investigate the relationship between nucleolar PARP-1 and memory impairment, we examined PARP-1 expression in the hippocampi of individuals with mild cognitive impairment (MCI) compared to control and AD cases. We used immunohistochemical techniques to examine the nucleolar distribution of PARP-1 in the Cornu Ammonis (CA region) of the hippocampus. PARP-1 positive cells were then scored for the presence or absence of PARP-1 in the nucleolus. We found a significant decrease of PARP-1 staining in the nucleolar compartment of hippocampal pyramidal cells in MCI compared with Control and AD. When the four CA (CA1-4) regions were considered separately, only the CA1 region showed significant differences in nucleolar PARP-1 with Control > AD > MCI cases. Categorization of nucleolar PARP-1 into “distinct” and “diffuse” groups suggest that most of the changes occur within the distinct group. In addition, measurements of the nucleolar diameter of nucleolar PARP-1 positive cells in CA2 and CA4 showed Control > MCI. Thus, MCI cases had a lower percentage of PARP-1 nucleolar positive cells in CA1 and smaller nucleolar diameters in CA2 and CA4, compared to Control. Our data suggest that disruption of nucleolar form and function is an early and important step in the progression of cognitive impairment.
Collapse
|
38
|
Def1 mediates the degradation of excess nucleolar protein Nop1 in budding yeast. Biochem Biophys Res Commun 2019; 519:302-308. [PMID: 31506176 DOI: 10.1016/j.bbrc.2019.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/01/2019] [Indexed: 01/22/2023]
Abstract
Nucleolar proteins such as Nop1/fibrillarin are degraded by nucleophagy in nutrient-starved conditions. However, whether and how excess nucleolar proteins are removed in normal conditions is unknown. Here we show that overexpressed nucleolar protein Nop1 is toxic and degraded in nutrient-rich conditions in budding yeast. The degradation was dependent on proteasomes. The CUE domain-containing protein Def1 mediated the degradation via the CUE domain and alleviated toxicity of Nop1 overexpression. Def1 was recruited to overexpressed Nop1 in the nucleolus. Ubiquitin mutants compromised this recruitment. This study revealed that Def1 is a novel factor for ubiquitin-dependent degradation of excess nucleolar proteins.
Collapse
|
39
|
Wagner Werneck Félix da Costa G, de Bello Cioffi M, Liehr T, Feldberg E, Antonio Carlos Bertollo L, Franco Molina W. Extensive Chromosomal Reorganization in Apistogramma Fishes (Cichlidae, Cichlinae) Fits the Complex Evolutionary Diversification of the Genus. Int J Mol Sci 2019; 20:E4077. [PMID: 31438504 PMCID: PMC6747227 DOI: 10.3390/ijms20174077] [Citation(s) in RCA: 5] [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: 07/30/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022] Open
Abstract
Neotropical cichlid fishes are one of the most diversified and evolutionarily successful species assemblages. Extremely similar forms and intraspecific polychromatism present challenges for the taxonomy of some of these groups. Several species complexes have a largely unknown origin and unresolved evolutionary processes. Dwarf cichlids of the genus Apistogramma, comprising more than a hundred species, exhibit intricate taxonomic and biogeographic patterns, with both allopatric and sympatric distributions. However, karyotype evolution and the role of chromosomal changes in Apistogramma are still unknown. In the present study, nine South American Apistogramma species were analyzed using conventional cytogenetic methods and the mapping of repetitive DNA sequences [18S rDNA, 5S rDNA, and (TTAGGG)n] by fluorescence in situ hybridization (FISH). Our results showed that Apistogramma has unique cytogenetic characteristics in relation to closely related groups, such as a reduced 2n and a large number of bi-armed chromosomes. Interspecific patterns revealed a scenario of remarkable karyotypic changes, including a reduction of 2n, the occurrence of B-chromosomes and evolutionary dynamic of rDNA tandem repeats. In addition to the well-known pre-zygotic reproductive isolation, the karyotype reorganization in the genus suggests that chromosomal changes could act as postzygotic barriers in areas where Apistogramma congeners overlap.
Collapse
Affiliation(s)
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz, Km. 235, C.P. 676, São Carlos 13565-905, SP, Brazil
| | - Thomas Liehr
- Institute of Human Genetics, Friedrich Schiller University, Am Klinikum 1, 07747 Jena, Germany.
| | - Eliana Feldberg
- Instituto Nacional de Pesquisas da Amazônia, Laboratório de Genética Animal, Av. André Araújo, 2936, Manaus 69077-000, AM, Brazil
| | - Luiz Antonio Carlos Bertollo
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz, Km. 235, C.P. 676, São Carlos 13565-905, SP, Brazil
| | - Wagner Franco Molina
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| |
Collapse
|
40
|
Correll CC, Bartek J, Dundr M. The Nucleolus: A Multiphase Condensate Balancing Ribosome Synthesis and Translational Capacity in Health, Aging and Ribosomopathies. Cells 2019; 8:cells8080869. [PMID: 31405125 PMCID: PMC6721831 DOI: 10.3390/cells8080869] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/31/2019] [Accepted: 08/06/2019] [Indexed: 12/21/2022] Open
Abstract
The nucleolus is the largest membrane-less structure in the eukaryotic nucleus. It is involved in the biogenesis of ribosomes, essential macromolecular machines responsible for synthesizing all proteins required by the cell. The assembly of ribosomes is evolutionarily conserved and is the most energy-consuming cellular process needed for cell growth, proliferation, and homeostasis. Despite the significance of this process, the intricate pathophysiological relationship between the nucleolus and protein synthesis has only recently begun to emerge. Here, we provide perspective on new principles governing nucleolar formation and the resulting multiphase organization driven by liquid-liquid phase separation. With recent advances in the structural analysis of ribosome formation, we highlight the current understanding of the step-wise assembly of pre-ribosomal subunits and the quality control required for proper function. Finally, we address how aging affects ribosome genesis and how genetic defects in ribosome formation cause ribosomopathies, complex diseases with a predisposition to cancer.
Collapse
Affiliation(s)
- Carl C Correll
- Center for Proteomics and Molecular Therapeutics, Rosalind Franklin University of Medicine & Science, North Chicago, IL 60064, USA.
| | - Jiri Bartek
- Danish Cancer Society Research Center, Genome Integrity Unit, DK-2100 Copenhagen, Denmark
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Miroslav Dundr
- Center for Cancer Cell Biology Immunology and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL 60064, USA.
| |
Collapse
|
41
|
Nelson JO, Watase GJ, Warsinger-Pepe N, Yamashita YM. Mechanisms of rDNA Copy Number Maintenance. Trends Genet 2019; 35:734-742. [PMID: 31395390 DOI: 10.1016/j.tig.2019.07.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 06/28/2019] [Accepted: 07/12/2019] [Indexed: 12/21/2022]
Abstract
rDNA, the genes encoding the RNA components of ribosomes (rRNA), are highly repetitive in all eukaryotic genomes, containing 100s to 1000s of copies, to meet the demand for ribosome biogenesis. rDNA genes are arranged in large stretches of tandem repeats, forming loci that are highly susceptible to copy loss due to their repetitiveness and active transcription throughout the cell cycle. Despite this inherent instability, rDNA copy number is generally maintained within a particular range in each species, pointing to the presence of mechanisms that maintain rDNA copy number in a homeostatic range. In this review, we summarize the current understanding of these maintenance mechanisms and how they sustain rDNA copy number throughout populations.
Collapse
Affiliation(s)
- Jonathan O Nelson
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
| | - George J Watase
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
| | - Natalie Warsinger-Pepe
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Yukiko M Yamashita
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|
42
|
Matos-Perdomo E, Machín F. Nucleolar and Ribosomal DNA Structure under Stress: Yeast Lessons for Aging and Cancer. Cells 2019; 8:cells8080779. [PMID: 31357498 PMCID: PMC6721496 DOI: 10.3390/cells8080779] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023] Open
Abstract
Once thought a mere ribosome factory, the nucleolus has been viewed in recent years as an extremely sensitive gauge of diverse cellular stresses. Emerging concepts in nucleolar biology include the nucleolar stress response (NSR), whereby a series of cell insults have a special impact on the nucleolus. These insults include, among others, ultra-violet radiation (UV), nutrient deprivation, hypoxia and thermal stress. While these stresses might influence nucleolar biology directly or indirectly, other perturbances whose origin resides in the nucleolar biology also trigger nucleolar and systemic stress responses. Among the latter, we find mutations in nucleolar and ribosomal proteins, ribosomal RNA (rRNA) processing inhibitors and ribosomal DNA (rDNA) transcription inhibition. The p53 protein also mediates NSR, leading ultimately to cell cycle arrest, apoptosis, senescence or differentiation. Hence, NSR is gaining importance in cancer biology. The nucleolar size and ribosome biogenesis, and how they connect with the Target of Rapamycin (TOR) signalling pathway, are also becoming important in the biology of aging and cancer. Simple model organisms like the budding yeast Saccharomyces cerevisiae, easy to manipulate genetically, are useful in order to study nucleolar and rDNA structure and their relationship with stress. In this review, we summarize the most important findings related to this topic.
Collapse
Affiliation(s)
- Emiliano Matos-Perdomo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Postgrado, Universidad de La Laguna, 38200 Tenerife, Spain
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain.
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 Tenerife, Spain.
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, 35450 Santa María de Guía, Gran Canaria, Spain.
| |
Collapse
|
43
|
Pirogov SA, Gvozdev VA, Klenov MS. Long Noncoding RNAs and Stress Response in the Nucleolus. Cells 2019; 8:cells8070668. [PMID: 31269716 PMCID: PMC6678565 DOI: 10.3390/cells8070668] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/15/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) perform diverse functions in the regulation of cellular processes. Here we consider a variety of lncRNAs found in the ribosome production center, the nucleolus, and focus on their role in the response to environmental stressors. Nucleolar lncRNAs ensure stress adaptation by cessation of resource-intensive ribosomal RNA (rRNA) synthesis and by inducing the massive sequestration of proteins within the nucleolus. Different cell states like quiescence and cancer are also controlled by specific lncRNAs in the nucleolus. Taken together, recent findings allow us to consider lncRNAs as multifunctional regulators of nucleolar activities, which are responsive to various physiological conditions.
Collapse
Affiliation(s)
- Sergei A Pirogov
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia
| | - Vladimir A Gvozdev
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia.
| | - Mikhail S Klenov
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia.
| |
Collapse
|
44
|
Srivastava R, Duan R, Ahn SH. Multiple roles of CTDK-I throughout the cell. Cell Mol Life Sci 2019; 76:2789-2797. [PMID: 31037337 PMCID: PMC11105739 DOI: 10.1007/s00018-019-03118-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/08/2019] [Accepted: 04/24/2019] [Indexed: 11/27/2022]
Abstract
The heterotrimeric carboxy-terminal domain kinase I (CTDK-I) in yeast is a cyclin-dependent kinase complex that is evolutionally conserved throughout eukaryotes and phosphorylates the C-terminal domain of the largest subunit of RNA polymerase II (RNApII) on the second-position serine (Ser2) residue of YSPTSPS heptapeptide repeats. CTDK-I plays indispensable roles in transcription elongation and transcription-coupled processing, such as the 3'-end processing of nascent mRNA transcripts. However, recent studies have revealed additional roles of CTDK-I beyond its primary effect on transcription by RNApII. Here, we describe recent advances in the regulation of genomic stability and rDNA integrity by CTDK-I and highlight the previously underappreciated cellular roles of CTDK-I in rRNA synthesis by RNA polymerase I and translational initiation and elongation. These multiple roles of CTDK-I throughout the cell expand our understanding of how this complex functions to coordinate diverse cellular processes through gene expression and how the human orthologue exerts its roles in diseased states such as tumorigenesis.
Collapse
Affiliation(s)
- Rakesh Srivastava
- Plant Molecular Biology and Genetic Engineering Division, CSIR-National Botanical Research Institute, Lucknow, U.P., 226001, India
| | - Ruxin Duan
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, Gyeonggi-do, 15588, Republic of Korea
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, Gyeonggi-do, 15588, Republic of Korea.
| |
Collapse
|
45
|
Hegedüs É, Kókai E, Nánási P, Imre L, Halász L, Jossé R, Antunovics Z, Webb MR, El Hage A, Pommier Y, Székvölgyi L, Dombrádi V, Szabó G. Endogenous single-strand DNA breaks at RNA polymerase II promoters in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 46:10649-10668. [PMID: 30445637 PMCID: PMC6237785 DOI: 10.1093/nar/gky743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/16/2018] [Indexed: 12/12/2022] Open
Abstract
Molecular combing and gel electrophoretic studies revealed endogenous nicks with free 3'OH ends at ∼100 kb intervals in the genomic DNA (gDNA) of unperturbed and G1-synchronized Saccharomyces cerevisiae cells. Analysis of the distribution of endogenous nicks by Nick ChIP-chip indicated that these breaks accumulated at active RNA polymerase II (RNAP II) promoters, reminiscent of the promoter-proximal transient DNA breaks of higher eukaryotes. Similar periodicity of endogenous nicks was found within the ribosomal rDNA cluster, involving every ∼10th of the tandemly repeated 9.1 kb units of identical sequence. Nicks were mapped by Southern blotting to a few narrow regions within the affected units. Three of them were overlapping the RNAP II promoters, while the ARS-containing IGS2 region was spared of nicks. By using a highly sensitive reverse-Southwestern blot method to map free DNA ends with 3'OH, nicks were shown to be distinct from other known rDNA breaks and linked to the regulation of rDNA silencing. Nicks in rDNA and the rest of the genome were typically found at the ends of combed DNA molecules, occasionally together with R-loops, comprising a major pool of vulnerable sites that are connected with transcriptional regulation.
Collapse
Affiliation(s)
- Éva Hegedüs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Endre Kókai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Nánási
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Imre
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Halász
- MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Rozenn Jossé
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Zsuzsa Antunovics
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Aziz El Hage
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Lóránt Székvölgyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Viktor Dombrádi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
46
|
Pohl TJ, Zakian VA. Pif1 family DNA helicases: A helpmate to RNase H? DNA Repair (Amst) 2019; 84:102633. [PMID: 31231063 DOI: 10.1016/j.dnarep.2019.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 01/21/2023]
Abstract
An R-loop is a structure that forms when an RNA transcript stays bound to the DNA strand that encodes it and leaves the complementary strand exposed as a loop of single stranded DNA. R-loops accumulate when the processing of RNA transcripts is impaired. The failure to remove these RNA-DNA hybrids can lead to replication fork stalling and genome instability. Resolution of R-loops is thought to be mediated mainly by RNase H enzymes through the removal and degradation of the RNA in the hybrid. However, DNA helicases can also dismantle R-loops by displacing the bound RNA. In particular, the Pif1 family DNA helicases have been shown to regulate R-loop formation at specific genomic loci, such as tRNA genes and centromeres. Here we review the roles of Pif1 family helicases in vivo and in vitro and discuss evidence that Pif1 family helicases act on RNA-DNA hybrids and highlight their potential roles in complementing RNase H for R-loop resolution.
Collapse
Affiliation(s)
- Thomas J Pohl
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, United States
| | - Virginia A Zakian
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, United States.
| |
Collapse
|
47
|
Wheeler JH, Young CKJ, Young MJ. Analysis of Human Mitochondrial DNA Content by Southern Blotting and Nonradioactive Probe Hybridization. CURRENT PROTOCOLS IN TOXICOLOGY 2019; 80:e75. [PMID: 30982231 PMCID: PMC6581606 DOI: 10.1002/cptx.75] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A single cell can contain several thousand copies of the mitochondrial DNA genome or mtDNA. Tools for assessing mtDNA content are necessary for clinical and toxicological research, as mtDNA depletion is linked to genetic disease and drug toxicity. For instance, mtDNA depletion syndromes are typically fatal childhood disorders that are characterized by severe declines in mtDNA content in affected tissues. Mitochondrial toxicity and mtDNA depletion have also been reported in human immunodeficiency virus-infected patients treated with certain nucleoside reverse transcriptase inhibitors. Further, cell culture studies have demonstrated that exposure to oxidative stress stimulates mtDNA degradation. Here we outline a Southern blot and nonradioactive digoxigenin-labeled probe hybridization method to estimate mtDNA content in human genomic DNA samples. © 2019 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Joel H. Wheeler
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Carolyn K. J. Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Matthew J. Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| |
Collapse
|
48
|
Yan Q, Zhu C, Guang S, Feng X. The Functions of Non-coding RNAs in rRNA Regulation. Front Genet 2019; 10:290. [PMID: 31024617 PMCID: PMC6463246 DOI: 10.3389/fgene.2019.00290] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 03/18/2019] [Indexed: 02/04/2023] Open
Abstract
Ribosomes are ribonucleoprotein machines that decode the genetic information embedded in mRNAs into polypeptides. Ribosome biogenesis is tightly coordinated and controlled from the transcription of pre-rRNAs to the assembly of ribosomes. Defects or disorders in rRNA production result in a number of human ribosomopathy diseases. During the processes of rRNA synthesis, non-coding RNAs, especially snoRNAs, play important roles in pre-rRNA transcription, processing, and maturation. Recent research has started to reveal that other long and short non-coding RNAs, including risiRNA, LoNA, and SLERT (among others), are also involved in pre-rRNA transcription and rRNA production. Here, we summarize the current understanding of the mechanisms of non-coding RNA-mediated rRNA generation and regulation and their biological roles.
Collapse
Affiliation(s)
- Qi Yan
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chengming Zhu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Shouhong Guang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China.,CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, China
| | - Xuezhu Feng
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| |
Collapse
|
49
|
Gorgoulis VG, Pefani D, Pateras IS, Trougakos IP. Integrating the DNA damage and protein stress responses during cancer development and treatment. J Pathol 2018; 246:12-40. [PMID: 29756349 PMCID: PMC6120562 DOI: 10.1002/path.5097] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 04/16/2018] [Accepted: 05/08/2018] [Indexed: 12/11/2022]
Abstract
During evolution, cells have developed a wide spectrum of stress response modules to ensure homeostasis. The genome and proteome damage response pathways constitute the pillars of this interwoven 'defensive' network. Consequently, the deregulation of these pathways correlates with ageing and various pathophysiological states, including cancer. In the present review, we highlight: (1) the structure of the genome and proteome damage response pathways; (2) their functional crosstalk; and (3) the conditions under which they predispose to cancer. Within this context, we emphasize the role of oncogene-induced DNA damage as a driving force that shapes the cellular landscape for the emergence of the various hallmarks of cancer. We also discuss potential means to exploit key cancer-related alterations of the genome and proteome damage response pathways in order to develop novel efficient therapeutic modalities. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Collapse
Affiliation(s)
- Vassilis G Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of MedicineNational and Kapodistrian University of AthensAthensGreece
- Biomedical Research Foundation of the Academy of AthensAthensGreece
- Faculty of Biology, Medicine and HealthUniversity of Manchester, Manchester Academic Health Science CentreManchesterUK
| | - Dafni‐Eleftheria Pefani
- CRUK/MRC Institute for Radiation Oncology, Department of OncologyUniversity of OxfordOxfordUK
| | - Ioannis S Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of MedicineNational and Kapodistrian University of AthensAthensGreece
| | - Ioannis P Trougakos
- Department of Cell Biology and Biophysics, Faculty of BiologyNational and Kapodistrian University of AthensAthensGreece
| |
Collapse
|
50
|
Evrin C, Maman JD, Diamante A, Pellegrini L, Labib K. Histone H2A-H2B binding by Pol α in the eukaryotic replisome contributes to the maintenance of repressive chromatin. EMBO J 2018; 37:embj.201899021. [PMID: 30104407 PMCID: PMC6166128 DOI: 10.15252/embj.201899021] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 06/18/2018] [Accepted: 07/24/2018] [Indexed: 11/13/2022] Open
Abstract
The eukaryotic replisome disassembles parental chromatin at DNA replication forks, but then plays a poorly understood role in the re‐deposition of the displaced histone complexes onto nascent DNA. Here, we show that yeast DNA polymerase α contains a histone‐binding motif that is conserved in human Pol α and is specific for histones H2A and H2B. Mutation of this motif in budding yeast cells does not affect DNA synthesis, but instead abrogates gene silencing at telomeres and mating‐type loci. Similar phenotypes are produced not only by mutations that displace Pol α from the replisome, but also by mutation of the previously identified histone‐binding motif in the CMG helicase subunit Mcm2, the human orthologue of which was shown to bind to histones H3 and H4. We show that chromatin‐derived histone complexes can be bound simultaneously by Mcm2, Pol α and the histone chaperone FACT that is also a replisome component. These findings indicate that replisome assembly unites multiple histone‐binding activities, which jointly process parental histones to help preserve silent chromatin during the process of chromosome duplication.
Collapse
Affiliation(s)
- Cecile Evrin
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, UK
| | - Joseph D Maman
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Aurora Diamante
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, UK
| |
Collapse
|