1
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Parasyraki E, Mallick M, Hatch V, Vastolo V, Musheev MU, Karaulanov E, Gopanenko A, Moxon S, Méndez-Lago M, Han D, Schomacher L, Mukherjee D, Niehrs C. 5-Formylcytosine is an activating epigenetic mark for RNA Pol III during zygotic reprogramming. Cell 2024:S0092-8674(24)00902-4. [PMID: 39214079 DOI: 10.1016/j.cell.2024.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/15/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024]
Abstract
5-Methylcytosine (5mC) is an established epigenetic mark in vertebrate genomic DNA, but whether its oxidation intermediates formed during TET-mediated DNA demethylation possess an instructive role of their own that is also physiologically relevant remains unresolved. Here, we reveal a 5-formylcytosine (5fC) nuclear chromocenter, which transiently forms during zygotic genome activation (ZGA) in Xenopus and mouse embryos. We identify this chromocenter as the perinucleolar compartment, a structure associated with RNA Pol III transcription. In Xenopus embryos, 5fC is highly enriched on Pol III target genes activated at ZGA, notably at oocyte-type tandem arrayed tRNA genes. By manipulating Tet and Tdg enzymes, we show that 5fC is required as a regulatory mark to promote Pol III recruitment as well as tRNA expression. Concordantly, 5fC modification of a tRNA transgene enhances its expression in vivo. The results establish 5fC as an activating epigenetic mark during zygotic reprogramming of Pol III gene expression.
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Affiliation(s)
| | | | - Victoria Hatch
- Institute of Molecular Biology (IMB), Mainz 55128, Germany
| | | | | | | | | | - Simon Moxon
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | | | - Dandan Han
- Institute of Molecular Biology (IMB), Mainz 55128, Germany
| | | | | | - Christof Niehrs
- Institute of Molecular Biology (IMB), Mainz 55128, Germany; Division of Molecular Embryology, DKFZ-ZMBH Alliance, Heidelberg 69120, Germany.
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2
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van Breugel ME, Gerber A, van Leeuwen F. The choreography of chromatin in RNA polymerase III regulation. Biochem Soc Trans 2024; 52:1173-1189. [PMID: 38666598 PMCID: PMC11346459 DOI: 10.1042/bst20230770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 06/27/2024]
Abstract
Regulation of eukaryotic gene expression involves a dynamic interplay between the core transcriptional machinery, transcription factors, and chromatin organization and modification. While this applies to transcription by all RNA polymerase complexes, RNA polymerase III (RNAPIII) seems to be atypical with respect to its mechanisms of regulation. One distinctive feature of most RNAPIII transcribed genes is that they are devoid of nucleosomes, which relates to the high levels of transcription. Moreover, most of the regulatory sequences are not outside but within the transcribed open chromatin regions. Yet, several lines of evidence suggest that chromatin factors affect RNAPIII dynamics and activity and that gene sequence alone does not explain the observed regulation of RNAPIII. Here we discuss the role of chromatin modification and organization of RNAPIII transcribed genes and how they interact with the core transcriptional RNAPIII machinery and regulatory DNA elements in and around the transcribed genes.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
| | - Alan Gerber
- Department of Neurosurgery, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam 1081HV, The Netherlands
- Cancer Center Amsterdam, Cancer Biology, Amsterdam 1081HV, The Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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3
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Schindler D, Walker RSK, Jiang S, Brooks AN, Wang Y, Müller CA, Cockram C, Luo Y, García A, Schraivogel D, Mozziconacci J, Pena N, Assari M, Sánchez Olmos MDC, Zhao Y, Ballerini A, Blount BA, Cai J, Ogunlana L, Liu W, Jönsson K, Abramczyk D, Garcia-Ruiz E, Turowski TW, Swidah R, Ellis T, Pan T, Antequera F, Shen Y, Nieduszynski CA, Koszul R, Dai J, Steinmetz LM, Boeke JD, Cai Y. Design, construction, and functional characterization of a tRNA neochromosome in yeast. Cell 2023; 186:5237-5253.e22. [PMID: 37944512 DOI: 10.1016/j.cell.2023.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
Here, we report the design, construction, and characterization of a tRNA neochromosome, a designer chromosome that functions as an additional, de novo counterpart to the native complement of Saccharomyces cerevisiae. Intending to address one of the central design principles of the Sc2.0 project, the ∼190-kb tRNA neochromosome houses all 275 relocated nuclear tRNA genes. To maximize stability, the design incorporates orthogonal genetic elements from non-S. cerevisiae yeast species. Furthermore, the presence of 283 rox recombination sites enables an orthogonal tRNA SCRaMbLE system. Following construction in yeast, we obtained evidence of a potent selective force, manifesting as a spontaneous doubling in cell ploidy. Furthermore, tRNA sequencing, transcriptomics, proteomics, nucleosome mapping, replication profiling, FISH, and Hi-C were undertaken to investigate questions of tRNA neochromosome behavior and function. Its construction demonstrates the remarkable tractability of the yeast model and opens up opportunities to directly test hypotheses surrounding these essential non-coding RNAs.
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Affiliation(s)
- Daniel Schindler
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, 35032 Marburg, Germany
| | - Roy S K Walker
- School of Engineering, Institute for Bioengineering, The University of Edinburgh, Edinburgh EH9 3BF, Scotland; School of Natural Sciences and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
| | - Shuangying Jiang
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Aaron N Brooks
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Yun Wang
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen 518120, China
| | - Carolin A Müller
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK; School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | - Charlotte Cockram
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Yisha Luo
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Alicia García
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Daniel Schraivogel
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Julien Mozziconacci
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Noah Pena
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Mahdi Assari
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | | | - Yu Zhao
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Alba Ballerini
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Benjamin A Blount
- Imperial College Centre for Synthetic Biology, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - Jitong Cai
- Department of Biomedical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lois Ogunlana
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Wei Liu
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Katarina Jönsson
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Dariusz Abramczyk
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Eva Garcia-Ruiz
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Tomasz W Turowski
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5a, 02-106 Warszawa, Poland
| | - Reem Swidah
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Tom Ellis
- Imperial College Centre for Synthetic Biology, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Francisco Antequera
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Yue Shen
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK; BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen 518120, China
| | - Conrad A Nieduszynski
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK; School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | - Romain Koszul
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Junbiao Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany; Department of Genetics and Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Yizhi Cai
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK.
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4
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Tian K, Wang R, Huang J, Wang H, Ji X. Subcellular localization shapes the fate of RNA polymerase III. Cell Rep 2023; 42:112941. [PMID: 37556328 DOI: 10.1016/j.celrep.2023.112941] [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: 02/08/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/11/2023] Open
Abstract
RNA polymerase III (Pol III) plays a vital role in transcription and as a viral-DNA sensor, but how it is assembled and distributed within cells remains poorly understood. Here, we show that Pol III is assembled with chaperones in the cytoplasm and forms transcription-dependent protein clusters upon transport into the nucleus. The largest subunit (RPC1) depletion through an auxin-inducible degron leads to rapid degradation and disassembly of Pol III complex in the nucleus and cytoplasm, respectively. This generates a pool of partially assembled Pol III intermediates, which can be rapidly mobilized into the nucleus upon the restoration of RPC1. Our study highlights the critical role of subcellular localization in determining Pol III's fate and provides insight into the dynamic regulation of nuclear Pol III levels and the origin of cytoplasmic Pol III complexes involved in mediating viral immunity.
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Affiliation(s)
- Kai Tian
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Rui Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Hui Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
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5
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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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6
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Tyczewska A, Rzepczak A, Sobańska D, Grzywacz K. The emerging roles of tRNAs and tRNA-derived fragments during aging: Lessons from studies on model organisms. Ageing Res Rev 2023; 85:101863. [PMID: 36707034 DOI: 10.1016/j.arr.2023.101863] [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: 10/26/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023]
Abstract
Aging is a gradual decline of various functions of organisms resulting in diminished abilities to protect against the environmental damage and reinforce the physiological harmony. Age-related functional declines have been thought to be passive and not regulated. However, studies on numerous model organisms, from yeast to mammals, exposed that the mechanisms of lifespan regulation are remarkably conserved throughout the evolution. Following the pioneering genetic studies in C. elegans, it has been shown that the genes related to the longevity are conserved in yeast, flies and mice. For a long time, tRNAs have been only considered as molecules transporting amino acids to the ribosome during translation. Nonetheless, it has become apparent from many biological studies that tRNAs are entangled in a variety of physiological and pathological processes. This review focuses on the emerging roles of tRNA-associated processes in aging and lifespan of model organisms. More specificaly, we present a summary on the importance of tRNA metabolism, epitranscriptome and possible roles of tRNA-derived fragments in aging and lifespan regulation. Better understanding of the basic mechanisms of aging could lead to the development of new diagnostics and treatments for aging-related diseases.
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Affiliation(s)
- Agata Tyczewska
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Alicja Rzepczak
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Daria Sobańska
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Kamilla Grzywacz
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
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7
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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.
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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
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8
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Wang L, Lin S. Emerging functions of tRNA modifications in mRNA translation and diseases. J Genet Genomics 2022; 50:223-232. [PMID: 36309201 DOI: 10.1016/j.jgg.2022.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
tRNAs are essential modulators that recognize mRNA codons and bridge amino acids for mRNA translation. The tRNAs are heavily modified, which is essential for forming a complex secondary structure that facilitates codon recognition and mRNA translation. In recent years, studies have identified the regulatory roles of tRNA modifications in mRNA translation networks. Misregulation of tRNA modifications is closely related to the progression of developmental diseases and cancers. In this review, we summarize the tRNA biogenesis process and then discuss the effects and mechanisms of tRNA modifications on tRNA processing and mRNA translation. Finally, we provide a comprehensive overview of tRNA modifications' physiological and pathological functions, focusing on diseases including cancers.
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Affiliation(s)
- Lu Wang
- Department of Medical Laboratory, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong 510515, China; Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Shuibin Lin
- Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510080, China.
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9
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Hayashi S, Matsui M, Ikeda A, Yoshihisa T. Six identical tRNATrpCCA genes express a similar amount of mature tRNATrpCCA but unequally contribute to yeast cell growth. Biosci Biotechnol Biochem 2022; 86:1398-1404. [PMID: 35948278 DOI: 10.1093/bbb/zbac134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/28/2022] [Indexed: 11/14/2022]
Abstract
Saccharomyces cerevisiae has six synonymous tRNATrpCCA genes encoding the identical sequence, including their intronic region. They are supposed to express tRNATrpCCA in the same quality and quantity. Here, we generated single to quintuple deletion strains with all the possible combinations of the synonymous tRNATrpCCA genes to analyze whether those individual genes equally contribute cell viability and tRNA production. The quintuple deletion strains that only harbor tW(CCA)J, tW(CCA)M, or tW(CCA)P were viable but almost lethal while the other quintuple deletions showed moderately impaired growth. Theses growth differences were not obvious among the quadruple deletion strains, which expressed almost one third of mature tRNATrpCCA in the wild type. Therefore, no dosage compensation operates for tRNATrpCCA amount, and growth variations among the quintuple deletion strains may not simply reflect differences in tRNATrpCCA shortage. Yeast may retain the redundancy of tRNATrpCCA genes for a noncanonical function(s) beyond supply of the tRNA to translation.
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Affiliation(s)
- Sachiko Hayashi
- Graduate School of Science, University of Hyogo, Ako-gun, Japan
| | | | | | - Tohru Yoshihisa
- Graduate School of Science, University of Hyogo, Ako-gun, Japan.,Faculty of Science, University of Hyogo
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10
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Aiello U, Challal D, Wentzinger G, Lengronne A, Appanah R, Pasero P, Palancade B, Libri D. Sen1 is a key regulator of transcription-driven conflicts. Mol Cell 2022; 82:2952-2966.e6. [PMID: 35839782 DOI: 10.1016/j.molcel.2022.06.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/04/2022] [Accepted: 06/13/2022] [Indexed: 10/17/2022]
Abstract
Cellular homeostasis requires the coordination of several machineries concurrently engaged in the DNA. Wide-spread transcription can interfere with other processes, and transcription-replication conflicts (TRCs) threaten genome stability. The conserved Sen1 helicase not only terminates non-coding transcription but also interacts with the replisome and reportedly resolves genotoxic R-loops. Sen1 prevents genomic instability, but how this relates to its molecular functions remains unclear. We generated high-resolution, genome-wide maps of transcription-dependent conflicts and R-loops using a Sen1 mutant that has lost interaction with the replisome but is termination proficient. We show that, under physiological conditions, Sen1 removes RNA polymerase II at TRCs within genes and the rDNA and at sites of transcription-transcription conflicts, thus qualifying as a "key regulator of conflicts." We demonstrate that genomic stability is affected by Sen1 mutation only when in addition to its role at the replisome, the termination of non-coding transcription or R-loop removal are additionally compromised.
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Affiliation(s)
- Umberto Aiello
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Drice Challal
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | | | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Rowin Appanah
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Benoit Palancade
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Domenico Libri
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France.
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11
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Nelson RS, Dammer EB, Santiago JV, Seyfried NT, Rangaraju S. Brain Cell Type-Specific Nuclear Proteomics Is Imperative to Resolve Neurodegenerative Disease Mechanisms. Front Neurosci 2022; 16:902146. [PMID: 35784845 PMCID: PMC9243337 DOI: 10.3389/fnins.2022.902146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/30/2022] [Indexed: 01/19/2023] Open
Abstract
Neurodegenerative diseases (NDs) involve complex cellular mechanisms that are incompletely understood. Emerging findings have revealed that disruption of nuclear processes play key roles in ND pathogenesis. The nucleus is a nexus for gene regulation and cellular processes that together, may underlie pathomechanisms of NDs. Furthermore, many genetic risk factors for NDs encode proteins that are either present in the nucleus or are involved in nuclear processes (for example, RNA binding proteins, epigenetic regulators, or nuclear-cytoplasmic transport proteins). While recent advances in nuclear transcriptomics have been significant, studies of the nuclear proteome in brain have been relatively limited. We propose that a comprehensive analysis of nuclear proteomic alterations of various brain cell types in NDs may provide novel biological and therapeutic insights. This may be feasible because emerging technical advances allow isolation and investigation of intact nuclei from post-mortem frozen human brain tissue with cell type-specific and single-cell resolution. Accordingly, nuclei of various brain cell types harbor unique protein markers which can be used to isolate cell-type specific nuclei followed by down-stream proteomics by mass spectrometry. Here we review the literature providing a rationale for investigating proteomic changes occurring in nuclei in NDs and then highlight the potential for brain cell type-specific nuclear proteomics to enhance our understanding of distinct cellular mechanisms that drive ND pathogenesis.
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Affiliation(s)
- Ruth S. Nelson
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Eric B. Dammer
- Department of Biochemistry, Emory University, Atlanta, GA, United States
| | | | | | - Srikant Rangaraju
- Department of Neurology, Emory University, Atlanta, GA, United States,*Correspondence: Srikant Rangaraju
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12
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Sizer RE, Chahid N, Butterfield SP, Donze D, Bryant NJ, White RJ. TFIIIC-based chromatin insulators through eukaryotic evolution. Gene X 2022; 835:146533. [PMID: 35623477 DOI: 10.1016/j.gene.2022.146533] [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: 08/12/2021] [Revised: 04/19/2022] [Accepted: 04/29/2022] [Indexed: 11/04/2022] Open
Abstract
Eukaryotic chromosomes are divided into domains with distinct structural and functional properties, such as differing levels of chromatin compaction and gene transcription. Domains of relatively compact chromatin and minimal transcription are termed heterochromatic, whereas euchromatin is more open and actively transcribed. Insulators separate these domains and maintain their distinct features. Disruption of insulators can cause diseases such as cancer. Many insulators contain tRNA genes (tDNAs), examples of which have been shown to block the spread of activating or silencing activities. This characteristic of specific tDNAs is conserved through evolution, such that human tDNAs can serve as barriers to the spread of silencing in fission yeast. Here we demonstrate that tDNAs from the methylotrophic fungus Pichia pastoris can function effectively as insulators in distantly-related budding yeast. Key to the function of tDNAs as insulators is TFIIIC, a transcription factor that is also required for their expression. TFIIIC binds additional loci besides tDNAs, some of which have insulator activity. Although the mechanistic basis of TFIIIC-based insulation has been studied extensively in yeast, it is largely uncharacterized in metazoa. Utilising publicly-available genome-wide ChIP-seq data, we consider the extent to which mechanisms conserved from yeast to man may suffice to allow efficient insulation by TFIIIC in the more challenging chromatin environments of metazoa and suggest features that may have been acquired during evolution to cope with new challenges. We demonstrate the widespread presence at human tDNAs of USF1, a transcription factor with well-established barrier activity in vertebrates. We predict that tDNA-based insulators in higher organisms have evolved through incorporation of modules, such as binding sites for factors like USF1 and CTCF that are absent from yeasts, thereby strengthening function and providing opportunities for regulation between cell types.
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Affiliation(s)
- Rebecca E Sizer
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Nisreen Chahid
- Department of Biology, The University of York, York YO10 5DD, UK
| | | | - David Donze
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Nia J Bryant
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, The University of York, York YO10 5DD, UK.
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13
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Sumner MC, Torrisi SB, Brickner DG, Brickner JH. Random sub-diffusion and capture of genes by the nuclear pore reduces dynamics and coordinates inter-chromosomal movement. eLife 2021; 10:66238. [PMID: 34002694 PMCID: PMC8195609 DOI: 10.7554/elife.66238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Hundreds of genes interact with the yeast nuclear pore complex (NPC), localizing at the nuclear periphery and clustering with co-regulated genes. Dynamic tracking of peripheral genes shows that they cycle on and off the NPC and that interaction with the NPC slows their sub-diffusive movement. Furthermore, NPC-dependent inter-chromosomal clustering leads to coordinated movement of pairs of loci separated by hundreds of nanometers. We developed fractional Brownian motion simulations for chromosomal loci in the nucleoplasm and interacting with NPCs. These simulations predict the rate and nature of random sub-diffusion during repositioning from nucleoplasm to periphery and match measurements from two different experimental models, arguing that recruitment to the nuclear periphery is due to random sub-diffusion and transient capture by NPCs. Finally, the simulations do not lead to inter-chromosomal clustering or coordinated movement, suggesting that interaction with the NPC is necessary, but not sufficient, to cause clustering.
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Affiliation(s)
- Michael Chas Sumner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Steven B Torrisi
- Department of Physics, Harvard University, Cambridge, United States
| | - Donna G Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
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14
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Jarrous N, Mani D, Ramanathan A. Coordination of transcription and processing of tRNA. FEBS J 2021; 289:3630-3641. [PMID: 33929081 DOI: 10.1111/febs.15904] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/02/2021] [Accepted: 04/28/2021] [Indexed: 12/17/2022]
Abstract
Coordination of transcription and processing of RNA is a basic principle in regulation of gene expression in eukaryotes. In the case of mRNA, coordination is primarily founded on a co-transcriptional processing mechanism by which a nascent precursor mRNA undergoes maturation via cleavage and modification by the transcription machinery. A similar mechanism controls the biosynthesis of rRNA. However, the coordination of transcription and processing of tRNA, a rather short transcript, remains unknown. Here, we present a model for high molecular weight initiation complexes of human RNA polymerase III that assemble on tRNA genes and process precursor transcripts to mature forms. These multifunctional initiation complexes may support co-transcriptional processing, such as the removal of the 5' leader of precursor tRNA by RNase P. Based on this model, maturation of tRNA is predetermined prior to transcription initiation.
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Affiliation(s)
- Nayef Jarrous
- Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Dhivakar Mani
- Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Aravind Ramanathan
- Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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15
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Sreekumar L, Kumari K, Guin K, Bakshi A, Varshney N, Thimmappa BC, Narlikar L, Padinhateeri R, Siddharthan R, Sanyal K. Orc4 spatiotemporally stabilizes centromeric chromatin. Genome Res 2021; 31:607-621. [PMID: 33514624 PMCID: PMC8015856 DOI: 10.1101/gr.265900.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/27/2021] [Indexed: 11/24/2022]
Abstract
The establishment of centromeric chromatin and its propagation by the centromere-specific histone CENPA is mediated by epigenetic mechanisms in most eukaryotes. DNA replication origins, origin binding proteins, and replication timing of centromere DNA are important determinants of centromere function. The epigenetically regulated regional centromeres in the budding yeast Candida albicans have unique DNA sequences that replicate earliest in every chromosome and are clustered throughout the cell cycle. In this study, the genome-wide occupancy of the replication initiation protein Orc4 reveals its abundance at all centromeres in C. albicans Orc4 is associated with four different DNA sequence motifs, one of which coincides with tRNA genes (tDNA) that replicate early and cluster together in space. Hi-C combined with genome-wide replication timing analyses identify that early replicating Orc4-bound regions interact with themselves stronger than with late replicating Orc4-bound regions. We simulate a polymer model of chromosomes of C. albicans and propose that the early replicating and highly enriched Orc4-bound sites preferentially localize around the clustered kinetochores. We also observe that Orc4 is constitutively localized to centromeres, and both Orc4 and the helicase Mcm2 are essential for cell viability and CENPA stability in C. albicans Finally, we show that new molecules of CENPA are recruited to centromeres during late anaphase/telophase, which coincides with the stage at which the CENPA-specific chaperone Scm3 localizes to the kinetochore. We propose that the spatiotemporal localization of Orc4 within the nucleus, in collaboration with Mcm2 and Scm3, maintains centromeric chromatin stability and CENPA recruitment in C. albicans.
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Affiliation(s)
- Lakshmi Sreekumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Kiran Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Research Academy, Mumbai 400076, India
- Department of Chemical Engineering, Monash University, Melbourne 3800, Australia
| | - Krishnendu Guin
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Asif Bakshi
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Neha Varshney
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Bhagya C Thimmappa
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Leelavati Narlikar
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rahul Siddharthan
- The Institute of Mathematical Sciences/HBNI, Taramani, Chennai 600113, India
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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16
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Guimarães AR, Correia I, Sousa I, Oliveira C, Moura G, Bezerra AR, Santos MAS. tRNAs as a Driving Force of Genome Evolution in Yeast. Front Microbiol 2021; 12:634004. [PMID: 33776966 PMCID: PMC7990762 DOI: 10.3389/fmicb.2021.634004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Transfer RNAs (tRNAs) are widely known for their roles in the decoding of the linear mRNA information into amino acid sequences of proteins. They are also multifunctional platforms in the translation process and have other roles beyond translation, including sensing amino acid abundance, interacting with the general stress response machinery, and modulating cellular adaptation, survival, and death. In this mini-review, we focus on the emerging role of tRNA genes in the organization and modification of the genomic architecture of yeast and the role of tRNA misexpression and decoding infidelity in genome stability, evolution, and adaption. We discuss published work showing how quickly tRNA genes can mutate to meet novel translational demands, how tRNAs speed up genome evolution, and how tRNA genes can be sites of genomic instability. We highlight recent works showing that loss of tRNA decoding fidelity and small alterations in tRNA expression have unexpected and profound impacts on genome stability. By dissecting these recent evidence, we hope to lay the groundwork that prompts future investigations on the mechanistic interplay between tRNAs and genome modification that likely triggers genome evolution.
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Affiliation(s)
- Ana Rita Guimarães
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Correia
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Inês Sousa
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Carla Oliveira
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Gabriela Moura
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ana Rita Bezerra
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Manuel A S Santos
- Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
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17
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Bizhanova A, Kaufman PD. Close to the edge: Heterochromatin at the nucleolar and nuclear peripheries. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2021; 1864:194666. [PMID: 33307247 PMCID: PMC7855492 DOI: 10.1016/j.bbagrm.2020.194666] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/11/2020] [Accepted: 11/29/2020] [Indexed: 02/06/2023]
Abstract
Chromatin is a dynamic structure composed of DNA, RNA, and proteins, regulating storage and expression of the genetic material in the nucleus. Heterochromatin plays a crucial role in driving the three-dimensional arrangement of the interphase genome, and in preserving genome stability by maintaining a subset of the genome in a silent state. Spatial genome organization contributes to normal patterns of gene function and expression, and is therefore of broad interest. Mammalian heterochromatin, the focus of this review, mainly localizes at the nuclear periphery, forming Lamina-associated domains (LADs), and at the nucleolar periphery, forming Nucleolus-associated domains (NADs). Together, these regions comprise approximately one-half of mammalian genomes, and most but not all loci within these domains are stochastically placed at either of these two locations after exit from mitosis at each cell cycle. Excitement about the role of these heterochromatic domains in early development has recently been heightened by the discovery that LADs appear at some loci in the preimplantation mouse embryo prior to other chromosomal features like compartmental identity and topologically-associated domains (TADs). While LADs have been extensively studied and mapped during cellular differentiation and early embryonic development, NADs have been less thoroughly studied. Here, we summarize pioneering studies of NADs and LADs, more recent advances in our understanding of cis/trans-acting factors that mediate these localizations, and discuss the functional significance of these associations.
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Affiliation(s)
- Aizhan Bizhanova
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Paul D Kaufman
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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18
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Abstract
As one of the most abundant and conserved RNA species, transfer RNAs (tRNAs) are well known for their role in reading the codons on messenger RNAs and translating them into proteins. In this review, we discuss the noncanonical functions of tRNAs. These include tRNAs as precursors to novel small RNA molecules derived from tRNAs, also called tRNA-derived fragments, that are abundant across species and have diverse functions in different biological processes, including regulating protein translation, Argonaute-dependent gene silencing, and more. Furthermore, the role of tRNAs in biosynthesis and other regulatory pathways, including nutrient sensing, splicing, transcription, retroelement regulation, immune response, and apoptosis, is reviewed. Genome organization and sequence variation of tRNA genes are also discussed in light of their noncanonical functions. Lastly, we discuss the recent applications of tRNAs in genome editing and microbiome sequencing.
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Affiliation(s)
- Zhangli Su
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia 22901, USA; , , ,
| | - Briana Wilson
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia 22901, USA; , , ,
| | - Pankaj Kumar
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia 22901, USA; , , ,
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia 22901, USA; , , ,
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19
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Iwasaki Y, Ikemura T, Kurokawa K, Okada N. Implication of a new function of human tDNAs in chromatin organization. Sci Rep 2020; 10:17440. [PMID: 33060757 PMCID: PMC7567086 DOI: 10.1038/s41598-020-74499-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/14/2020] [Indexed: 02/03/2023] Open
Abstract
Transfer RNA genes (tDNAs) are essential genes that encode tRNAs in all species. To understand new functions of tDNAs, other than that of encoding tRNAs, we used ENCODE data to examine binding characteristics of transcription factors (TFs) for all tDNA regions (489 loci) in the human genome. We divided the tDNAs into three groups based on the number of TFs that bound to them. At the two extremes were tDNAs to which many TFs bound (Group 1) and those to which no TFs bound (Group 3). Several TFs involved in chromatin remodeling such as ATF3, EP300 and TBL1XR1 bound to almost all Group 1 tDNAs. Furthermore, almost all Group 1 tDNAs included DNase I hypersensitivity sites and may thus interact with other chromatin regions through their bound TFs, and they showed highly conserved synteny across tetrapods. In contrast, Group 3 tDNAs did not possess these characteristics. These data suggest the presence of a previously uncharacterized function of these tDNAs. We also examined binding of CTCF to tDNAs and their involvement in topologically associating domains (TADs) and lamina-associated domains (LADs), which suggest a new perspective on the evolution and function of tDNAs.
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Affiliation(s)
- Yuki Iwasaki
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
- Center for Information Biology, National Institute of Genetics, Mishima, Japan
| | - Toshimichi Ikemura
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Ken Kurokawa
- Center for Information Biology, National Institute of Genetics, Mishima, Japan
| | - Norihiro Okada
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan.
- School of Pharmacy, Kitasato University, Sagamihara, Kanagawa, Japan.
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20
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Hummel G, Berr A, Graindorge S, Cognat V, Ubrig E, Pflieger D, Molinier J, Drouard L. Epigenetic silencing of clustered tRNA genes in Arabidopsis. Nucleic Acids Res 2020; 48:10297-10312. [PMID: 32941623 PMCID: PMC7544208 DOI: 10.1093/nar/gkaa766] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/21/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022] Open
Abstract
Beyond their key role in translation, cytosolic transfer RNAs (tRNAs) are involved in a wide range of other biological processes. Nuclear tRNA genes (tDNAs) are transcribed by the RNA polymerase III (RNAP III) and cis-elements, trans-factors as well as genomic features are known to influence their expression. In Arabidopsis, besides a predominant population of dispersed tDNAs spread along the 5 chromosomes, some clustered tDNAs have been identified. Here, we demonstrate that these tDNA clusters are transcriptionally silent and that pathways involved in the maintenance of DNA methylation play a predominant role in their repression. Moreover, we show that clustered tDNAs exhibit repressive chromatin features whilst their dispersed counterparts contain permissive euchromatic marks. This work demonstrates that both genomic and epigenomic contexts are key players in the regulation of tDNAs transcription. The conservation of most of these regulatory processes suggests that this pioneering work in Arabidopsis can provide new insights into the regulation of RNA Pol III transcription in other organisms, including vertebrates.
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Affiliation(s)
- Guillaume Hummel
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Alexandre Berr
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Stéfanie Graindorge
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Valérie Cognat
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Elodie Ubrig
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - David Pflieger
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Jean Molinier
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Laurence Drouard
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
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21
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Quantitative Analysis of Spatial Distributions of All tRNA Genes in Budding Yeast. Biophys J 2020; 118:2181-2192. [PMID: 31951810 DOI: 10.1016/j.bpj.2019.12.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 10/25/2022] Open
Abstract
In the budding yeast nucleus, transfer RNA (tRNA) genes are considered to localize in the vicinity of the nucleolus; however, the use of Hi-C and fluorescent repressor-operator system techniques has clearly indicated that the tRNA genes are distributed not only around the nucleolus but also at other nuclear locations. However, there are some discrepancies between Hi-C data analysis and the results indicated from fluorescence microscopy data. To fill these gaps, we systematically clarified the spatial arrangements of all tRNA genes in the budding yeast nucleus using the genome simulation model developed by us. The simulation results revealed that out of 275 tRNA genes, 58% were found to be spatially distributed around the centromeres, 16% were distributed around the ribosomal DNA regions, and the remaining 26% were distributed between the centromeres and ribosomal DNA regions. Furthermore, 1% of all tRNA genes were found to be spatially distributed around the nuclear envelope, 30% were distributed around the center of the nucleus, and the remaining 69% were distributed between the nuclear envelope and the center of the nucleus. The percentage distributions were highly similar to those of the 176 tRNA genes encoding tRNAs having an anticodon for the optimal codons. The simulation results also revealed that the spatial arrangements of tRNA genes were affected by linear genomic distance from the tethering elements such as the centromeres or telomeres; however, the distance was only one of the factors to determine spatial distribution. This study also investigates whether tRNA gene transcriptional levels depend on the arrangements in the budding yeast nucleus by integrating the genome simulation model with tRNA sequencing data. The results suggest that the transcriptional levels did not depend on the arrangements in the nucleus. By using the genome simulation model, we showed the possibility of quantitatively analyzing genome structures.
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22
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Luo Z, Hoffmann SA, Jiang S, Cai Y, Dai J. Probing eukaryotic genome functions with synthetic chromosomes. Exp Cell Res 2020; 390:111936. [PMID: 32165165 DOI: 10.1016/j.yexcr.2020.111936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/25/2020] [Accepted: 02/29/2020] [Indexed: 02/07/2023]
Abstract
The ability to redesign and reconstruct a cell at whole-genome level provides new platforms for biological study. The international synthetic yeast genome project-Sc2.0, designed by interrogating knowledge amassed by the yeast community to date, exemplifies how a classical synthetic biology "design-build-test-learn" engineering cycle can effectively test hypotheses about various genome fundamentals. The genome reshuffling SCRaMbLE system implemented in synthetic yeast strains also provides unprecedented diversified resources for genotype-phenotype study and yeast metabolic engineering. Further development of genome synthesis technology will shed new lights on complex biological processes in higher eukaryotes.
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Affiliation(s)
- Zhouqing Luo
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Stefan A Hoffmann
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, M1 7DN, Manchester, UK
| | - Shuangying Jiang
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Yizhi Cai
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, M1 7DN, Manchester, UK.
| | - Junbiao Dai
- Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Center for Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518055, China.
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23
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Khalique A, Mattijssen S, Haddad AF, Chaudhry S, Maraia RJ. Targeting mitochondrial and cytosolic substrates of TRIT1 isopentenyltransferase: Specificity determinants and tRNA-i6A37 profiles. PLoS Genet 2020; 16:e1008330. [PMID: 32324744 PMCID: PMC7200024 DOI: 10.1371/journal.pgen.1008330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 05/05/2020] [Accepted: 03/18/2020] [Indexed: 11/29/2022] Open
Abstract
The tRNA isopentenyltransferases (IPTases), which add an isopentenyl group to N6 of A37 (i6A37) of certain tRNAs, are among a minority of enzymes that modify cytosolic and mitochondrial tRNAs. Pathogenic mutations to the human IPTase, TRIT1, that decrease i6A37 levels, cause mitochondrial insufficiency that leads to neurodevelopmental disease. We show that TRIT1 encodes an amino-terminal mitochondrial targeting sequence (MTS) that directs mitochondrial import and modification of mitochondrial-tRNAs. Full understanding of IPTase function must consider the tRNAs selected for modification, which vary among species, and in their cytosol and mitochondria. Selection is principally via recognition of the tRNA A36-A37-A38 sequence. An exception is unmodified tRNATrpCCA-A37-A38 in Saccharomyces cerevisiae, whereas tRNATrpCCA is readily modified in Schizosaccharomyces pombe, indicating variable IPTase recognition systems and suggesting that additional exceptions may account for some of the tRNA-i6A37 paucity in higher eukaryotes. Yet TRIT1 had not been characterized for restrictive type substrate-specific recognition. We used i6A37-dependent tRNA-mediated suppression and i6A37-sensitive northern blotting to examine IPTase activities in S. pombe and S. cerevisiae lacking endogenous IPTases on a diversity of tRNA-A36-A37-A38 substrates. Point mutations to the TRIT1 MTS that decrease human mitochondrial import, decrease modification of mitochondrial but not cytosolic tRNAs in both yeasts. TRIT1 exhibits clear substrate-specific restriction against a cytosolic-tRNATrpCCA-A37-A38. Additional data suggest that position 32 of tRNATrpCCA is a conditional determinant for substrate-specific i6A37 modification by the restrictive IPTases, Mod5 and TRIT1. The cumulative biochemical and phylogenetic sequence analyses provide new insights into IPTase activities and determinants of tRNA-i6A37 profiles in cytosol and mitochondria.
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Affiliation(s)
- Abdul Khalique
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sandy Mattijssen
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alexander F. Haddad
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Shereen Chaudhry
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard J. Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
- Commissioned Corps, United States Public Health Service, Rockville, Maryland, United States of America
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24
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Holla S, Dhakshnamoorthy J, Folco HD, Balachandran V, Xiao H, Sun LL, Wheeler D, Zofall M, Grewal SIS. Positioning Heterochromatin at the Nuclear Periphery Suppresses Histone Turnover to Promote Epigenetic Inheritance. Cell 2019; 180:150-164.e15. [PMID: 31883795 DOI: 10.1016/j.cell.2019.12.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/29/2019] [Accepted: 12/04/2019] [Indexed: 01/09/2023]
Abstract
In eukaryotes, heterochromatin is generally located at the nuclear periphery. This study investigates the biological significance of perinuclear positioning for heterochromatin maintenance and gene silencing. We identify the nuclear rim protein Amo1NUPL2 as a factor required for the propagation of heterochromatin at endogenous and ectopic sites in the fission yeast genome. Amo1 associates with the Rix1PELP1-containing RNA processing complex RIXC and with the histone chaperone complex FACT. RIXC, which binds to heterochromatin protein Swi6HP1 across silenced chromosomal domains and to surrounding boundary elements, connects heterochromatin with Amo1 at the nuclear periphery. In turn, the Amo1-enriched subdomain is critical for Swi6 association with FACT that precludes histone turnover to promote gene silencing and preserve epigenetic stability of heterochromatin. In addition to uncovering conserved factors required for perinuclear positioning of heterochromatin, these analyses elucidate a mechanism by which a peripheral subdomain enforces stable gene repression and maintains heterochromatin in a heritable manner.
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Affiliation(s)
- Sahana Holla
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jothy Dhakshnamoorthy
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - H Diego Folco
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vanivilasini Balachandran
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hua Xiao
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ling-Ling Sun
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - David Wheeler
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martin Zofall
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Lawrimore CJ, Bloom K. Common Features of the Pericentromere and Nucleolus. Genes (Basel) 2019; 10:E1029. [PMID: 31835574 PMCID: PMC6947172 DOI: 10.3390/genes10121029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/05/2019] [Accepted: 12/07/2019] [Indexed: 12/20/2022] Open
Abstract
Both the pericentromere and the nucleolus have unique characteristics that distinguish them amongst the rest of genome. Looping of pericentromeric DNA, due to structural maintenance of chromosome (SMC) proteins condensin and cohesin, drives its ability to maintain tension during metaphase. Similar loops are formed via condensin and cohesin in nucleolar ribosomal DNA (rDNA). Condensin and cohesin are also concentrated in transfer RNA (tRNA) genes, genes which may be located within the pericentromere as well as tethered to the nucleolus. Replication fork stalling, as well as downstream consequences such as genomic recombination, are characteristic of both the pericentromere and rDNA. Furthermore, emerging evidence suggests that the pericentromere may function as a liquid-liquid phase separated domain, similar to the nucleolus. We therefore propose that the pericentromere and nucleolus, in part due to their enrichment of SMC proteins and others, contain similar domains that drive important cellular activities such as segregation, stability, and repair.
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Affiliation(s)
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA;
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26
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Hayashi S, Mori S, Suzuki T, Suzuki T, Yoshihisa T. Impact of intron removal from tRNA genes on Saccharomyces cerevisiae. Nucleic Acids Res 2019; 47:5936-5949. [PMID: 30997502 PMCID: PMC6582322 DOI: 10.1093/nar/gkz270] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/28/2019] [Accepted: 04/04/2019] [Indexed: 12/31/2022] Open
Abstract
In eukaryotes and archaea, tRNA genes frequently contain introns, which are removed during maturation. However, biological roles of tRNA introns remain elusive. Here, we constructed a complete set of Saccharomyces cerevisiae strains in which the introns were removed from all the synonymous genes encoding 10 different tRNA species. All the intronless strains were viable, but the tRNAPheGAA and tRNATyrGUA intronless strains displayed slow growth, cold sensitivity and defective growth under respiratory conditions, indicating physiological importance of certain tRNA introns. Northern analyses revealed that removal of the introns from genes encoding three tRNAs reduced the amounts of the corresponding mature tRNAs, while it did not affect aminoacylation. Unexpectedly, the tRNALeuCAA intronless strain showed reduced 5.8S rRNA levels and abnormal nucleolar morphology. Because pseudouridine (Ψ) occurs at position 34 of the tRNAIleUAU anticodon in an intron-dependent manner, tRNAIleUAU in the intronless strain lost Ψ34. However, in a portion of tRNAIleUAU population, position 34 was converted into 5-carbamoylmethyluridine (ncm5U), which could reduce decoding fidelity. In summary, our results demonstrate that, while introns are dispensable for cell viability, some introns have diverse roles, such as ensuring proper growth under various conditions and controlling the appropriate anticodon modifications for accurate pairing with the codon.
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Affiliation(s)
- Sachiko Hayashi
- Graduate School of Life Science, University of Hyogo, Ako-gun 678-1297, Japan
| | - Shunsuke Mori
- Graduate School of Materials Science, Nagoya University, Nagoya 464-8602, Japan
| | - Takeo Suzuki
- Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
| | - Tsutomu Suzuki
- Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
| | - Tohru Yoshihisa
- Graduate School of Life Science, University of Hyogo, Ako-gun 678-1297, Japan
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Cerqueira AV, Lemos B. Ribosomal DNA and the Nucleolus as Keystones of Nuclear Architecture, Organization, and Function. Trends Genet 2019; 35:710-723. [PMID: 31447250 DOI: 10.1016/j.tig.2019.07.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 12/12/2022]
Abstract
The multicopy ribosomal DNA (rDNA) array gives origin to the nucleolus, a large nonmembrane-bound organelle that occupies a substantial volume within the cell nucleus. The rDNA/nucleolus has emerged as a coordinating hub in which seemingly disparate cellular functions converge, and from which a variety of cellular and organismal phenotypes emerge. However, the role of the nucleolus as a determinant and organizer of nuclear architecture and other epigenetic states of the genome is not well understood. We discuss the role of rDNA and the nucleolus in nuclear organization and function - from nucleolus-associated domains (NADs) to the regulation of imprinted loci and X chromosome inactivation, as well as rDNA contact maps that anchor and position the rDNA relative to the rest of the genome. The influence of the nucleolus on nuclear organization undoubtedly modulates diverse biological processes from metabolism to cell proliferation, genome-wide gene expression, maintenance of epigenetic states, and aging.
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Affiliation(s)
- Amanda V Cerqueira
- Department of Environmental Health, Program in Molecular and Integrative Physiological Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Bernardo Lemos
- Department of Environmental Health, Program in Molecular and Integrative Physiological Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
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28
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Trotta E. RNA polymerase II (RNAP II)-associated factors are recruited to tRNA loci, revealing that RNAP II- and RNAP III-mediated transcriptions overlap in yeast. J Biol Chem 2019; 294:12349-12358. [PMID: 31235518 PMCID: PMC6699833 DOI: 10.1074/jbc.ra119.008529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/19/2019] [Indexed: 07/24/2023] Open
Abstract
In yeast (Saccharomyces cerevisiae), the synthesis of tRNAs by RNA polymerase III (RNAP III) down-regulates the transcription of the nearby RNAP II-transcribed genes by a mechanism that is poorly understood. To clarify the basis of this tRNA gene-mediated (TGM) silencing, here, conducting a bioinformatics analysis of available ChIP-chip and ChIP-sequencing genomic data from yeast, we investigated whether the RNAP III transcriptional machinery can recruit protein factors required for RNAP II transcription. An analysis of 46 genome-wide protein-density profiles revealed that 12 factors normally implicated in RNAP II-mediated gene transcription are more enriched at tRNA than at mRNA loci. These 12 factors typically have RNA-binding properties, participate in the termination stage of the RNAP II transcription, and preferentially localize to the tRNA loci by a mechanism that apparently is based on the RNAP III transcription level. The factors included two kinases of RNAP II (Bur1 and Ctk1), a histone demethylase (Jhd2), and a mutated form of a nucleosome-remodeling factor (Spt6) that have never been reported to be recruited to tRNA loci. Moreover, we show that the expression levels of RNAP II-transcribed genes downstream of tRNA loci correlate with the distance from the tRNA gene by a mechanism that depends on their orientation. These results are consistent with the notion that pre-tRNAs recruit RNAP II-associated factors, thereby reducing the availability of these factors for RNAP II transcription and contributing, at least in part, to the TGM-silencing mechanism.
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Affiliation(s)
- Edoardo Trotta
- Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche (CNR), Roma 00133, Italy.
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29
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Kofuji S, Hirayama A, Eberhardt AO, Kawaguchi R, Sugiura Y, Sampetrean O, Ikeda Y, Warren M, Sakamoto N, Kitahara S, Yoshino H, Yamashita D, Sumita K, Wolfe K, Lange L, Ikeda S, Shimada H, Minami N, Malhotra A, Morioka S, Ban Y, Asano M, Flanary VL, Ramkissoon A, Chow LML, Kiyokawa J, Mashimo T, Lucey G, Mareninov S, Ozawa T, Onishi N, Okumura K, Terakawa J, Daikoku T, Wise-Draper T, Majd N, Kofuji K, Sasaki M, Mori M, Kanemura Y, Smith EP, Anastasiou D, Wakimoto H, Holland EC, Yong WH, Horbinski C, Nakano I, DeBerardinis RJ, Bachoo RM, Mischel PS, Yasui W, Suematsu M, Saya H, Soga T, Grummt I, Bierhoff H, Sasaki AT. IMP dehydrogenase-2 drives aberrant nucleolar activity and promotes tumorigenesis in glioblastoma. Nat Cell Biol 2019; 21:1003-1014. [PMID: 31371825 PMCID: PMC6686884 DOI: 10.1038/s41556-019-0363-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 06/18/2019] [Indexed: 12/17/2022]
Abstract
In many cancers, high proliferation rates correlate with elevation of rRNA and tRNA levels, and nucleolar hypertrophy. However, the underlying mechanisms linking increased nucleolar transcription and tumorigenesis are only minimally understood. Here we show that IMP dehydrogenase-2 (IMPDH2), the rate-limiting enzyme for de novo guanine nucleotide biosynthesis, is overexpressed in the highly lethal brain cancer glioblastoma. This leads to increased rRNA and tRNA synthesis, stabilization of the nucleolar GTP-binding protein nucleostemin, and enlarged, malformed nucleoli. Pharmacological or genetic inactivation of IMPDH2 in glioblastoma reverses these effects and inhibits cell proliferation, whereas untransformed glia cells are unaffected by similar IMPDH2 perturbations. Impairment of IMPDH2 activity triggers nucleolar stress and growth arrest of glioblastoma cells even in the absence of functional p53. Our results reveal that upregulation of IMPDH2 is a prerequisite for the occurance of aberrant nucleolar function and increased anabolic processes in glioblastoma, which constitutes a primary event in gliomagenesis.
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Affiliation(s)
- Satoshi Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Akiyoshi Hirayama
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Alexander Otto Eberhardt
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena, Jena, Germany
- Leibniz-Institute on Aging-Fritz Lipmann Institute, Jena, Germany
| | - Risa Kawaguchi
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Yuki Sugiura
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Oltea Sampetrean
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Yoshiki Ikeda
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Mikako Warren
- Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles and Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Naoya Sakamoto
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shuji Kitahara
- Department of Anatomy and Developmental Biology, Tokyo Women's Medical University School of Medicine, Tokyo, Japan
| | - Hirofumi Yoshino
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Daisuke Yamashita
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kazutaka Sumita
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kara Wolfe
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lisa Lange
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena, Jena, Germany
- Leibniz-Institute on Aging-Fritz Lipmann Institute, Jena, Germany
| | - Satsuki Ikeda
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Hiroko Shimada
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Noriaki Minami
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Akshiv Malhotra
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Shin Morioka
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yuki Ban
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Maya Asano
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Victoria L Flanary
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Annmarie Ramkissoon
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Lionel M L Chow
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Juri Kiyokawa
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tomoyuki Mashimo
- Department of Internal Medicine; Harold C. Simmons Comprehensive Cancer Center; Annette G. Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Greg Lucey
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sergey Mareninov
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tatsuya Ozawa
- Division of Human Biology, Solid Tumor and Translational Research, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Nobuyuki Onishi
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Koichi Okumura
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jumpei Terakawa
- Division of Transgenic Animal Science, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Takiko Daikoku
- Division of Transgenic Animal Science, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Trisha Wise-Draper
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Nazanin Majd
- Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kaori Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Mika Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Masaru Mori
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Yonehiro Kanemura
- Department of Biomedical Research and Innovation, Institute for Clinical Research, National Hospital Organization Osaka National Hospital, Osaka, Japan
| | - Eric P Smith
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Hiroaki Wakimoto
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Eric C Holland
- Division of Human Biology, Solid Tumor and Translational Research, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - William H Yong
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Craig Horbinski
- Department of Pathology, University of Kentucky College of Medicine, Lexington, KY, USA
- Departments of Pathology and Neurosurgery, Northwestern University, Chicago, IL, USA
| | - Ichiro Nakano
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ralph J DeBerardinis
- Howard Hughes Medical Institute; Children's Medical Center Research Institute; Department of Pediatrics and Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Robert M Bachoo
- Department of Internal Medicine; Harold C. Simmons Comprehensive Cancer Center; Annette G. Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Paul S Mischel
- Ludwig Institute for Cancer Research; Department of Pathology; Moores Cancer Center, University of California San Diego School of Medicine, La Jolla, CA, USA
| | - Wataru Yasui
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Makoto Suematsu
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Hideyuki Saya
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- AMED-CREST, AMED, Tokyo, Japan
| | - Ingrid Grummt
- Division of Molecular Biology of the Cell II, German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Holger Bierhoff
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena, Jena, Germany
- Leibniz-Institute on Aging-Fritz Lipmann Institute, Jena, Germany
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
- Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, Cincinnati, OH, USA.
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30
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Hummel G, Warren J, Drouard L. The multi-faceted regulation of nuclear tRNA gene transcription. IUBMB Life 2019; 71:1099-1108. [PMID: 31241827 DOI: 10.1002/iub.2097] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/16/2019] [Indexed: 12/31/2022]
Abstract
Transfer RNAs are among the most ancient molecules of life on earth. Beyond their crucial role in protein synthesis as carriers of amino acids, they are also important players in a plethora of other biological processes. Many debates in term of biogenesis, regulation and function persist around these fascinating non-coding RNAs. Our review focuses on the first step of their biogenesis in eukaryotes, i.e. their transcription from nuclear genes. Numerous and complementary ways have emerged during evolution to regulate transfer RNA gene transcription. Here, we will summarize the different actors implicated in this process: cis-elements, trans-factors, genomic contexts, epigenetic environments and finally three-dimensional organization of nuclear genomes. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1099-1108, 2019.
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Affiliation(s)
- Guillaume Hummel
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Jessica Warren
- Department of biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Laurence Drouard
- Institut de biologie moléculaire des plantes-CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
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31
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Chromosome conformation capture that detects novel cis- and trans-interactions in budding yeast. Methods 2019; 170:4-16. [PMID: 31252061 DOI: 10.1016/j.ymeth.2019.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/17/2019] [Accepted: 06/21/2019] [Indexed: 11/22/2022] Open
Abstract
Chromosome Conformation Capture (3C) has emerged as a powerful approach for revealing the conformation and features of three-dimensional (3D) genomic organization. Yet attainment of higher resolution in organisms with compact genomes presents a challenge. Here, we describe modifications in the 3C technique that substantially enhance its resolution and sensitivity when applied to the 3D genome of budding yeast. Keys to our approach include use of a 4 bp cutter, Taq I, for cleaving the genome and quantitative PCR for measuring the frequency of ligation. Most importantly, we normalize the percent digestion at each restriction site to account for variation in accessibility of local chromatin structure under a given physiological condition. This strategy has led to the detection of physical interactions between regulatory elements and gene coding regions as well as intricate, stimulus-specific interchromosomal interactions between activated genes. We provide an algorithm that incorporates these and other modifications and allows quantitative determination of chromatin interaction frequencies in yeast under any physiological condition.
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32
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Martínez-Calvillo S, Florencio-Martínez LE, Nepomuceno-Mejía T. Nucleolar Structure and Function in Trypanosomatid Protozoa. Cells 2019; 8:cells8050421. [PMID: 31071985 PMCID: PMC6562600 DOI: 10.3390/cells8050421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 12/12/2022] Open
Abstract
The nucleolus is the conspicuous nuclear body where ribosomal RNA genes are transcribed by RNA polymerase I, pre-ribosomal RNA is processed, and ribosomal subunits are assembled. Other important functions have been attributed to the nucleolus over the years. Here we review the current knowledge about the structure and function of the nucleolus in the trypanosomatid parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania ssp., which represent one of the earliest branching lineages among the eukaryotes. These protozoan parasites present a single nucleolus that is preserved throughout the closed nuclear division, and that seems to lack fibrillar centers. Trypanosomatids possess a relatively low number of rRNA genes, which encode rRNA molecules that contain large expansion segments, including several that are trypanosomatid-specific. Notably, the large subunit rRNA (28S-type) is fragmented into two large and four small rRNA species. Hence, compared to other organisms, the rRNA primary transcript requires additional processing steps in trypanosomatids. Accordingly, this group of parasites contains the highest number ever reported of snoRNAs that participate in rRNA processing. The number of modified rRNA nucleotides in trypanosomatids is also higher than in other organisms. Regarding the structure and biogenesis of the ribosomes, recent cryo-electron microscopy analyses have revealed several trypanosomatid-specific features that are discussed here. Additional functions of the nucleolus in trypanosomatids are also reviewed.
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Affiliation(s)
- Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
| | - Luis E Florencio-Martínez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
| | - Tomás Nepomuceno-Mejía
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
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33
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tRNA Genes Affect Chromosome Structure and Function via Local Effects. Mol Cell Biol 2019; 39:MCB.00432-18. [PMID: 30718362 DOI: 10.1128/mcb.00432-18] [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: 09/06/2018] [Accepted: 01/18/2019] [Indexed: 11/20/2022] Open
Abstract
The genome is packaged and organized in an ordered, nonrandom manner, and specific chromatin segments contact nuclear substructures to mediate this organization. tRNA genes (tDNAs) are binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the roles of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacked any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromatin architecture or chromosome tethering and mobility. However, loss of tDNAs affects local nucleosome positioning and the binding of SMC proteins at these loci. The absence of tDNAs also leads to changes in centromere clustering and a reduction in the frequency of long-range HML-HMR heterochromatin clustering with concomitant effects on gene silencing. We propose that the tDNAs primarily affect local chromatin structure, which results in effects on long-range chromosome architecture.
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34
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Tuorto F, Parlato R. rRNA and tRNA Bridges to Neuronal Homeostasis in Health and Disease. J Mol Biol 2019; 431:1763-1779. [PMID: 30876917 DOI: 10.1016/j.jmb.2019.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 12/11/2022]
Abstract
Dysregulation of protein translation is emerging as a unifying mechanism in the pathogenesis of many neuronal disorders. Ribosomal RNA (rRNA) and transfer RNA (tRNA) are structural molecules that have complementary and coordinated functions in protein synthesis. Defects in both rRNAs and tRNAs have been described in mammalian brain development, neurological syndromes, and neurodegeneration. In this review, we present the molecular mechanisms that link aberrant rRNA and tRNA transcription, processing and modifications to translation deficits, and neuropathogenesis. We also discuss the interdependence of rRNA and tRNA biosynthesis and how their metabolism brings together proteotoxic stress and impaired neuronal homeostasis.
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Affiliation(s)
- Francesca Tuorto
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
| | - Rosanna Parlato
- Institute of Applied Physiology, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany; Institute of Anatomy and Cell Biology, Medical Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany.
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35
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Abstract
A wide variety of factors are required for the conversion of pre-tRNA molecules into the mature tRNAs that function in translation. To identify factors influencing tRNA biogenesis, we previously performed a screen for strains carrying mutations that induce lethality when combined with a sup61-T47:2C allele, encoding a mutant form of [Formula: see text]. Analyzes of two complementation groups led to the identification of Tan1 as a protein involved in formation of the modified nucleoside N4-acetylcytidine (ac4C) in tRNA and Bud13 as a factor controlling the levels of ac4C by promoting TAN1 pre-mRNA splicing. Here, we describe the remaining complementation groups and show that they include strains with mutations in genes for known tRNA biogenesis factors that modify (DUS2, MOD5 and TRM1), transport (LOS1), or aminoacylate (SES1) [Formula: see text]. Other strains carried mutations in genes for factors involved in rRNA/mRNA synthesis (RPA49, RRN3 and MOT1) or magnesium uptake (ALR1). We show that mutations in not only DUS2, LOS1 and SES1 but also in RPA49, RRN3 and MOT1 cause a reduction in the levels of the altered [Formula: see text]. These results indicate that Rpa49, Rrn3 and Mot1 directly or indirectly influence [Formula: see text] biogenesis.
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Affiliation(s)
- Fu Xu
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Yang Zhou
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Anders S Byström
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
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36
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Baudement MO, Cournac A, Court F, Seveno M, Parrinello H, Reynes C, Sabatier R, Bouschet T, Yi Z, Sallis S, Tancelin M, Rebouissou C, Cathala G, Lesne A, Mozziconacci J, Journot L, Forné T. High-salt-recovered sequences are associated with the active chromosomal compartment and with large ribonucleoprotein complexes including nuclear bodies. Genome Res 2018; 28:1733-1746. [PMID: 30287550 PMCID: PMC6211644 DOI: 10.1101/gr.237073.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/10/2018] [Indexed: 12/18/2022]
Abstract
The mammalian cell nucleus contains numerous discrete suborganelles named nuclear bodies. While recruitment of specific genomic regions into these large ribonucleoprotein (RNP) complexes critically contributes to higher-order functional chromatin organization, such regions remain ill-defined. We have developed the high-salt–recovered sequences-sequencing (HRS-seq) method, a straightforward genome-wide approach whereby we isolated and sequenced genomic regions associated with large high-salt insoluble RNP complexes. By using mouse embryonic stem cells (ESCs), we showed that these regions essentially correspond to the most highly expressed genes, and to cis-regulatory sequences like super-enhancers, that belong to the active A chromosomal compartment. They include both cell-type–specific genes, such as pluripotency genes in ESCs, and housekeeping genes associated with nuclear bodies, such as histone and snRNA genes that are central components of Histone Locus Bodies and Cajal bodies. We conclude that HRSs are associated with the active chromosomal compartment and with large RNP complexes including nuclear bodies. Association of such chromosomal regions with nuclear bodies is in agreement with the recently proposed phase separation model for transcription control and might thus play a central role in organizing the active chromosomal compartment in mammals.
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Affiliation(s)
| | | | - Franck Court
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France
| | - Marie Seveno
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France
| | - Hugues Parrinello
- MGX, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France
| | - Christelle Reynes
- IGF, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France
| | - Robert Sabatier
- IGF, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France
| | - Tristan Bouschet
- IGF, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France
| | - Zhou Yi
- Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F-75252, Paris, France
| | - Sephora Sallis
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France
| | | | | | - Guy Cathala
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France
| | - Annick Lesne
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France.,Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F-75252, Paris, France
| | - Julien Mozziconacci
- Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F-75252, Paris, France
| | - Laurent Journot
- MGX, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France.,IGF, Université de Montpellier, CNRS, INSERM, F-34094, Montpellier, France
| | - Thierry Forné
- IGMM, Université de Montpellier, CNRS, F-34293, Montpellier, France
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37
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Abstract
The pool of transfer RNA (tRNA) molecules in cells allows the ribosome to decode genetic information. This repertoire of molecular decoders is positioned in the crossroad of the genome, the transcriptome, and the proteome. Omics and systems biology now allow scientists to explore the entire repertoire of tRNAs of many organisms, revealing basic exciting biology. The tRNA gene set of hundreds of species is now characterized, in addition to the tRNA genes of organelles and viruses. Genes encoding tRNAs for certain anticodon types appear in dozens of copies in a genome, while others are universally absent from any genome. Transcriptome measurement of tRNAs is challenging, but in recent years new technologies have allowed researchers to determine the dynamic expression patterns of tRNAs. These advances reveal that availability of ready-to-translate tRNA molecules is highly controlled by several transcriptional and posttranscriptional regulatory processes. This regulation shapes the proteome according to the cellular state. The tRNA pool profoundly impacts many aspects of cellular and organismal life, including protein expression level, translation accuracy, adequacy of folding, and even mRNA stability. As a result, the shape of the tRNA pool affects organismal health and may participate in causing conditions such as cancer and neurological conditions.
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Affiliation(s)
- Roni Rak
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Orna Dahan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
| | - Yitzhak Pilpel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100 Israel;
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38
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Cheung S, Manhas S, Measday V. Retrotransposon targeting to RNA polymerase III-transcribed genes. Mob DNA 2018; 9:14. [PMID: 29713390 PMCID: PMC5911963 DOI: 10.1186/s13100-018-0119-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 04/16/2018] [Indexed: 12/20/2022] Open
Abstract
Retrotransposons are genetic elements that are similar in structure and life cycle to retroviruses by replicating via an RNA intermediate and inserting into a host genome. The Saccharomyces cerevisiae (S. cerevisiae) Ty1-5 elements are long terminal repeat (LTR) retrotransposons that are members of the Ty1-copia (Pseudoviridae) or Ty3-gypsy (Metaviridae) families. Four of the five S. cerevisiae Ty elements are inserted into the genome upstream of RNA Polymerase (Pol) III-transcribed genes such as transfer RNA (tRNA) genes. This particular genomic locus provides a safe environment for Ty element insertion without disruption of the host genome and is a targeting strategy used by retrotransposons that insert into compact genomes of hosts such as S. cerevisiae and the social amoeba Dictyostelium. The mechanism by which Ty1 targeting is achieved has been recently solved due to the discovery of an interaction between Ty1 Integrase (IN) and RNA Pol III subunits. We describe the methods used to identify the Ty1-IN interaction with Pol III and the Ty1 targeting consequences if the interaction is perturbed. The details of Ty1 targeting are just beginning to emerge and many unexplored areas remain including consideration of the 3-dimensional shape of genome. We present a variety of other retrotransposon families that insert adjacent to Pol III-transcribed genes and the mechanism by which the host machinery has been hijacked to accomplish this targeting strategy. Finally, we discuss why retrotransposons selected Pol III-transcribed genes as a target during evolution and how retrotransposons have shaped genome architecture.
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Affiliation(s)
- Stephanie Cheung
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
| | - Savrina Manhas
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
| | - Vivien Measday
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
- Department of Food Science, Wine Research Centre, Faculty of Land and Food Systems, University of British Columbia, Room 325-2205 East Mall, Vancouver, British Columbia V6T 1Z4 Canada
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39
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Chatterjee K, Nostramo RT, Wan Y, Hopper AK. tRNA dynamics between the nucleus, cytoplasm and mitochondrial surface: Location, location, location. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:373-386. [PMID: 29191733 PMCID: PMC5882565 DOI: 10.1016/j.bbagrm.2017.11.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/19/2017] [Accepted: 11/23/2017] [Indexed: 01/20/2023]
Abstract
Although tRNAs participate in the essential function of protein translation in the cytoplasm, tRNA transcription and numerous processing steps occur in the nucleus. This subcellular separation between tRNA biogenesis and function requires that tRNAs be efficiently delivered to the cytoplasm in a step termed "primary tRNA nuclear export". Surprisingly, tRNA nuclear-cytoplasmic traffic is not unidirectional, but, rather, movement is bidirectional. Cytoplasmic tRNAs are imported back to the nucleus by the "tRNA retrograde nuclear import" step which is conserved from budding yeast to vertebrate cells and has been hijacked by viruses, such as HIV, for nuclear import of the viral reverse transcription complex in human cells. Under appropriate environmental conditions cytoplasmic tRNAs that have been imported into the nucleus return to the cytoplasm via the 3rd nuclear-cytoplasmic shuttling step termed "tRNA nuclear re-export", that again is conserved from budding yeast to vertebrate cells. We describe the 3 steps of tRNA nuclear-cytoplasmic movements and their regulation. There are multiple tRNA nuclear export and import pathways. The different tRNA nuclear exporters appear to possess substrate specificity leading to the tantalizing possibility that the cellular proteome may be regulated at the level of tRNA nuclear export. Moreover, in some organisms, such as budding yeast, the pre-tRNA splicing heterotetrameric endonuclease (SEN), which removes introns from pre-tRNAs, resides on the cytoplasmic surface of the mitochondria. Therefore, we also describe the localization of the SEN complex to mitochondria and splicing of pre-tRNA on mitochondria, which occurs prior to the participation of tRNAs in protein translation. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Kunal Chatterjee
- The Ohio State University Comprehensive Cancer Research Center, United States; Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Regina T Nostramo
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Yao Wan
- The Ohio State University Comprehensive Cancer Research Center, United States; Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Anita K Hopper
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States.
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40
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Abstract
The nucleolus is the largest nuclear sub-compartment in which the early steps of ribosome biogenesis take place. It also plays an essential role in the assembly and function of non-ribosomal ribonucleoprotein (RNP) complexes, controls cell cycle progression and senses environmental stress. The spatial organization and dynamics of nucleolar proteins and RNA is regulated at different structural levels, which finally determine nucleolar architecture. The intimate link between nucleolar structure and function is reflected by transcription-dependent changes in nucleolus-associated chromatin, overall morphological alterations in response to external cues, and the liquid droplet-like behavior of nucleolar compartments. Here we provide a concise overview of the latest studies which integrate novel trends in nucleolar architecture research into the context of cell biology.
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Affiliation(s)
- Attila Németh
- Institute of Neuropathology, University of Giessen, Germany.
| | - Ingrid Grummt
- Molecular Biology of the Cell II, German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany.
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41
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Shah FR, Bhat YA, Wani AH. Subnuclear distribution of proteins: Links with genome architecture. Nucleus 2018; 9:42-55. [PMID: 28910577 PMCID: PMC5973252 DOI: 10.1080/19491034.2017.1361578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/25/2017] [Accepted: 07/26/2017] [Indexed: 02/08/2023] Open
Abstract
Metazoan genomes have a hierarchal 3-dimensional (3D) organization scaling from nucleosomes, loops, topologically associating domains (TADs), compartments, to chromosome territories. The 3D organization of genome has been linked with development, differentiation and disease. However, the principles governing the 3D chromatin architecture are just beginning to get unraveled. The nucleus has very high concentration of proteins and these proteins are either diffusely distributed throughout the nucleus, or aggregated in the form of foci/bodies/clusters/speckles or in combination of both. Several evidences suggest that the distribution of proteins within the nuclear space is linked to the organization and function of genome. Here, we describe advances made in understanding the relationship between subnuclear distribution of proteins and genome architecture.
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Affiliation(s)
- Fouziya R. Shah
- Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Younus A. Bhat
- Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Ajazul H. Wani
- Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
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42
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Heat Shock Protein Genes Undergo Dynamic Alteration in Their Three-Dimensional Structure and Genome Organization in Response to Thermal Stress. Mol Cell Biol 2017; 37:MCB.00292-17. [PMID: 28970326 DOI: 10.1128/mcb.00292-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/15/2017] [Indexed: 01/11/2023] Open
Abstract
Three-dimensional (3D) chromatin organization is important for proper gene regulation, yet how the genome is remodeled in response to stress is largely unknown. Here, we use a highly sensitive version of chromosome conformation capture in combination with fluorescence microscopy to investigate Heat Shock Protein (HSP) gene conformation and 3D nuclear organization in budding yeast. In response to acute thermal stress, HSP genes undergo intense intragenic folding interactions that go well beyond 5'-3' gene looping previously described for RNA polymerase II genes. These interactions include looping between upstream activation sequence (UAS) and promoter elements, promoter and terminator regions, and regulatory and coding regions (gene "crumpling"). They are also dynamic, being prominent within 60 s, peaking within 2.5 min, and attenuating within 30 min, and correlate with HSP gene transcriptional activity. With similarly striking kinetics, activated HSP genes, both chromosomally linked and unlinked, coalesce into discrete intranuclear foci. Constitutively transcribed genes also loop and crumple yet fail to coalesce. Notably, a missense mutation in transcription factor TFIIB suppresses gene looping, yet neither crumpling nor HSP gene coalescence is affected. An inactivating promoter mutation, in contrast, obviates all three. Our results provide evidence for widespread, transcription-associated gene crumpling and demonstrate the de novo assembly and disassembly of HSP gene foci.
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43
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Abstract
The three-dimensional (3D) genome structure is highly ordered by a hierarchy of organizing events ranging from enhancer-promoter or gene-gene contacts to chromosomal territorial arrangement. It is becoming clear that the cohesin and condensin complexes are key molecular machines that organize the 3D genome structure. These complexes are highly conserved from simple systems, e.g., yeast cells, to the much more complex human system. Therefore, knowledge from the budding and fission yeast systems illuminates highly conserved molecular mechanisms of how cohesin and condensin establish the functional 3D genome structures. Here I discuss how these complexes are recruited across the yeast genomes, mediate distinct genome-organizing events such as gene contacts and topological domain formation, and participate in important nuclear activities including transcriptional regulation and chromosomal dynamics.
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Affiliation(s)
- Ken-Ichi Noma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA;
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44
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Generation of an arginine-tRNA-adapted Saccharomyces cerevisiae strain for effective heterologous protein expression. Curr Genet 2017; 64:589-598. [PMID: 29098364 DOI: 10.1007/s00294-017-0774-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/30/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
Abstract
The tRNA population reflects the codon bias of the organism and affects the translation of heterologous target mRNA molecules. In this study, Saccharomyces cerevisiae strains with modified levels of rare tRNA were engineered, that allowed efficient generation of recombinant proteins with unfavorable codon usage. We established a novel synthetic tRNA expression cassette and verified functional nonsense suppressor tRNAGlnSCUA generation in a stop codon read-through assay with a modified β-galactosidase reporter gene. Correlation between altered tRNA and protein level was shown by survival of copper sensitive S. cerevisiae cells in the presence of copper ions by an increased transcription of tRNAArgCCG molecules, recognizing rare codons in a modified CUP1 gene. Genome integration of tRNA expression cassette led to the generation of arginine-tRNA-adapted S. cerevisiae strains, which showed elevated tRNA levels (tRNAArgCCG, tRNAArgGCG and tRNAArgUCG) pairing to rare codons. The modified strain MNY3 revealed a considerably improved monitoring of protein-protein interaction from Aspergillus fumigatus bait and prey sequences in yeast two-hybrid experiments. In future, this principle to overcome limited recombinant protein expression by tRNA adaption of expression strains instead of codon adaption might provide new designer yeast cells for an efficient protein production and for improved genome-wide protein-protein interaction analyses.
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45
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Mercy G, Mozziconacci J, Scolari VF, Yang K, Zhao G, Thierry A, Luo Y, Mitchell LA, Shen M, Shen Y, Walker R, Zhang W, Wu Y, Xie ZX, Luo Z, Cai Y, Dai J, Yang H, Yuan YJ, Boeke JD, Bader JS, Muller H, Koszul R. 3D organization of synthetic and scrambled chromosomes. Science 2017; 355:355/6329/eaaf4597. [PMID: 28280150 DOI: 10.1126/science.aaf4597] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 02/01/2017] [Indexed: 11/02/2022]
Abstract
Although the design of the synthetic yeast genome Sc2.0 is highly conservative with respect to gene content, the deletion of several classes of repeated sequences and the introduction of thousands of designer changes may affect genome organization and potentially alter cellular functions. We report here the Hi-C-determined three-dimensional (3D) conformations of Sc2.0 chromosomes. The absence of repeats leads to a smoother contact pattern and more precisely tractable chromosome conformations, and the large-scale genomic organization is globally unaffected by the presence of synthetic chromosome(s). Two exceptions are synIII, which lacks the silent mating-type cassettes, and synXII, specifically when the ribosomal DNA is moved to another chromosome. We also exploit the contact maps to detect rearrangements induced in SCRaMbLE (synthetic chromosome rearrangement and modification by loxP-mediated evolution) strains.
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Affiliation(s)
- Guillaume Mercy
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, Paris 75015, France.,UMR3525, Centre National de la Recherche Scientifique (CNRS), Paris 75015, France.,Sorbonne Universités, Université Pierre et Marie Curie (Université Paris 6), Paris 75005, France
| | - Julien Mozziconacci
- Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR7600, Université Pierre et Marie Curie (Université Paris 6), Sorbonne Universités, Paris, France
| | - Vittore F Scolari
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, Paris 75015, France.,UMR3525, Centre National de la Recherche Scientifique (CNRS), Paris 75015, France
| | - Kun Yang
- Department of Biomedical Engineering and High-Throughput Biology Center, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Guanghou Zhao
- Key Laboratory for Industrial Biocatalysis (Ministry of Education), Key Laboratory of Bioinformatics (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Agnès Thierry
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, Paris 75015, France.,UMR3525, Centre National de la Recherche Scientifique (CNRS), Paris 75015, France
| | - Yisha Luo
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Leslie A Mitchell
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, Langone Medical Center, New York University, New York, NY 10016, USA
| | - Michael Shen
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, Langone Medical Center, New York University, New York, NY 10016, USA
| | - Yue Shen
- BGI-Shenzhen, Shenzhen 518083, China.,BGI-Qingdao, Qingdao 266555, China.,School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Roy Walker
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Weimin Zhang
- Key Laboratory for Industrial Biocatalysis (Ministry of Education), Key Laboratory of Bioinformatics (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yi Wu
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Ze-Xiong Xie
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Zhouqing Luo
- Key Laboratory for Industrial Biocatalysis (Ministry of Education), Key Laboratory of Bioinformatics (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yizhi Cai
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Junbiao Dai
- Key Laboratory for Industrial Biocatalysis (Ministry of Education), Key Laboratory of Bioinformatics (Ministry of Education), Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Huanming Yang
- James D. Watson Institute of Genome Sciences, Hangzhou 310058, China.,BGI-Shenzhen, Shenzhen 518083, China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, Langone Medical Center, New York University, New York, NY 10016, USA
| | - Joel S Bader
- Department of Biomedical Engineering and High-Throughput Biology Center, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Héloïse Muller
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, Paris 75015, France. .,UMR3525, Centre National de la Recherche Scientifique (CNRS), Paris 75015, France
| | - Romain Koszul
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, Paris 75015, France. .,UMR3525, Centre National de la Recherche Scientifique (CNRS), Paris 75015, France
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46
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Brickner J. Genetic and epigenetic control of the spatial organization of the genome. Mol Biol Cell 2017; 28:364-369. [PMID: 28137949 PMCID: PMC5341720 DOI: 10.1091/mbc.e16-03-0149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 11/11/2022] Open
Abstract
Eukaryotic genomes are spatially organized within the nucleus by chromosome folding, interchromosomal contacts, and interaction with nuclear structures. This spatial organization is observed in diverse organisms and both reflects and contributes to gene expression and differentiation. This leads to the notion that the arrangement of the genome within the nucleus has been shaped and conserved through evolutionary processes and likely plays an adaptive function. Both DNA-binding proteins and changes in chromatin structure influence the positioning of genes and larger domains within the nucleus. This suggests that the spatial organization of the genome can be genetically encoded by binding sites for DNA-binding proteins and can also involve changes in chromatin structure, potentially through nongenetic mechanisms. Here I briefly discuss the results that support these ideas and their implications for how genomes encode spatial organization.
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Affiliation(s)
- Jason Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
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47
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Van Bortle K, Phanstiel DH, Snyder MP. Topological organization and dynamic regulation of human tRNA genes during macrophage differentiation. Genome Biol 2017; 18:180. [PMID: 28931413 PMCID: PMC5607496 DOI: 10.1186/s13059-017-1310-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/25/2017] [Indexed: 12/11/2022] Open
Abstract
Background The human genome is hierarchically organized into local and long-range structures that help shape cell-type-specific transcription patterns. Transfer RNA (tRNA) genes (tDNAs), which are transcribed by RNA polymerase III (RNAPIII) and encode RNA molecules responsible for translation, are dispersed throughout the genome and, in many cases, linearly organized into genomic clusters with other tDNAs. Whether the location and three-dimensional organization of tDNAs contribute to the activity of these genes has remained difficult to address, due in part to unique challenges related to tRNA sequencing. We therefore devised integrated tDNA expression profiling, a method that combines RNAPIII mapping with biotin-capture of nascent tRNAs. We apply this method to the study of dynamic tRNA gene regulation during macrophage development and further integrate these data with high-resolution maps of 3D chromatin structure. Results Integrated tDNA expression profiling reveals domain-level and loop-based organization of tRNA gene transcription during cellular differentiation. tRNA genes connected by DNA loops, which are proximal to CTCF binding sites and expressed at elevated levels compared to non-loop tDNAs, change coordinately with tDNAs and protein-coding genes at distal ends of interactions mapped by in situ Hi-C. We find that downregulated tRNA genes are specifically marked by enhanced promoter-proximal binding of MAF1, a transcriptional repressor of RNAPIII activity, altogether revealing multiple levels of tDNA regulation during cellular differentiation. Conclusions We present evidence of both local and coordinated long-range regulation of human tDNA expression, suggesting the location and organization of tRNA genes contribute to dynamic tDNA activity during macrophage development. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1310-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kevin Van Bortle
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Douglas H Phanstiel
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA.,Thurston Arthritis Research Center and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Michael P Snyder
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA.
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48
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Moriggi G, Gaspar SG, Nieto B, Bustelo XR, Dosil M. Focal accumulation of preribosomes outside the nucleolus during metaphase-anaphase in budding yeast. RNA (NEW YORK, N.Y.) 2017; 23:1432-1443. [PMID: 28588079 PMCID: PMC5558912 DOI: 10.1261/rna.061259.117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Saccharomyces cerevisiae contains one nucleolus that remains intact in the mother-cell side of the nucleus throughout most of mitosis. Based on this, it is assumed that the bulk of ribosome production during cell division occurs in the mother cell. Here, we show that the ribosome synthesis machinery localizes not only in the nucleolus but also at a center that is present in the bud side of the nucleus after the initiation of mitosis. This center can be visualized by live microscopy as a punctate body located in close proximity to the nuclear envelope and opposite to the nucleolus. It contains ribosomal DNA (rDNA) and precursors of both 40S and 60S ribosomal subunits. Proteins that actively participate in ribosome synthesis, but not functionally defective variants, accumulate in that site. The formation of this body occurs in the metaphase-to-anaphase transition when discrete regions of rDNA occasionally exit the nucleolus and move into the bud. Collectively, our data unveil the existence of a previously unknown mechanism for preribosome accumulation at the nuclear periphery in budding yeast. We propose that this might be a strategy to expedite the delivery of ribosomes to the growing bud.
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Affiliation(s)
- Giulia Moriggi
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - Sonia G Gaspar
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - Blanca Nieto
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - Xosé R Bustelo
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Centro de Investigación del Cáncer, 37007 Salamanca, Spain
| | - Mercedes Dosil
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Departamento de Bioquímica y Biología Molecular, University of Salamanca, 37007 Salamanca, Spain
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49
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Jarrous N. Roles of RNase P and Its Subunits. Trends Genet 2017; 33:594-603. [PMID: 28697848 DOI: 10.1016/j.tig.2017.06.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/18/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022]
Abstract
Recent studies show that nuclear RNase P is linked to chromatin structure and function. Thus, variants of this ribonucleoprotein (RNP) complex bind to chromatin of small noncoding RNA genes; integrate into initiation complexes of RNA polymerase (Pol) III; repress histone H3.3 nucleosome deposition; control tRNA and PIWI-interacting RNA (piRNA) gene clusters for genome defense; and respond to Werner syndrome helicase (WRN)-related replication stress and DNA double-strand breaks (DSBs). Likewise, the related RNase MRP and RMRP-TERT (telomerase reverse transcriptase) are implicated in RNA-dependent RNA polymerization for chromatin silencing, whereas the telomerase carries out RNA-dependent DNA polymerization for telomere lengthening. Remarkably, the four RNPs share several protein subunits, including two Alba-like chromatin proteins that possess DEAD-like and ATPase motifs found in chromatin modifiers and remodelers. Based on available data, RNase P and related RNPs act in transition processes of DNA to RNA and vice versa and connect these processes to genome preservation, including replication, DNA repair, and chromatin remodeling.
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Affiliation(s)
- Nayef Jarrous
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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50
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Read DF, Waller TJ, Tse E, Southworth DR, Engelke DR, Smaldino PJ. Aggregation of Mod5 is affected by tRNA binding with implications for tRNA gene-mediated silencing. FEBS Lett 2017; 591:1601-1610. [PMID: 28303570 DOI: 10.1002/1873-3468.12627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 12/24/2022]
Abstract
Mod5 is a multifunctional protein that modifies a subset of tRNAs in the cytoplasm and is also required for an RNA-mediated form of transcriptional silencing. Previous in vivo studies have shown that the nuclear silencing function of Mod5 does not require that the causative tRNA gene encode a Mod5 substrate, although Mod5 is still required. However, previous data have not directly tested whether Mod5 can directly bind substrate and nonsubstrate RNAs. We herein demonstrate that Mod5 directly binds to both substrate and nonsubstrate RNAs, including a highly structured, non-tRNA sequence (5S-rRNA), consistent with previous in vivo data. Furthermore, we show that some RNAs drastically change the aggregation behavior of Mod5 with implications for tRNA gene-mediated silencing.
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Affiliation(s)
- David F Read
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Thomas J Waller
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Eric Tse
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.,Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Daniel R Southworth
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.,Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - David R Engelke
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.,University of Colorado Denver/Anschutz Medical Campus, Aurora, CO, USA
| | - Philip J Smaldino
- Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.,Biology, Ball State University, Muncie, IN, USA
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