1
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Kofler L, Grundmann L, Gerhalter M, Prattes M, Merl-Pham J, Zisser G, Grishkovskaya I, Hodirnau VV, Vareka M, Breinbauer R, Hauck SM, Haselbach D, Bergler H. The novel ribosome biogenesis inhibitor usnic acid blocks nucleolar pre-60S maturation. Nat Commun 2024; 15:7511. [PMID: 39209816 PMCID: PMC11362459 DOI: 10.1038/s41467-024-51754-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 08/11/2024] [Indexed: 09/04/2024] Open
Abstract
The formation of new ribosomes is tightly coordinated with cell growth and proliferation. In eukaryotes, the correct assembly of all ribosomal proteins and RNAs follows an intricate scheme of maturation and rearrangement steps across three cellular compartments: the nucleolus, nucleoplasm, and cytoplasm. We demonstrate that usnic acid, a lichen secondary metabolite, inhibits the maturation of the large ribosomal subunit in yeast. We combine biochemical characterization of pre-ribosomal particles with a quantitative single-particle cryo-EM approach to monitor changes in nucleolar particle populations upon drug treatment. Usnic acid rapidly blocks the transition from nucleolar state B to C of Nsa1-associated pre-ribosomes, depleting key maturation factors such as Dbp10 and hindering pre-rRNA processing. This primary nucleolar block rapidly rebounds on earlier stages of the pathway which highlights the regulatory linkages between different steps. In summary, we provide an in-depth characterization of the effect of usnic acid on ribosome biogenesis, which may have implications for its reported anti-cancer activities.
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Affiliation(s)
- Lisa Kofler
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Lorenz Grundmann
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | | | - Michael Prattes
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Juliane Merl-Pham
- Core Facility Metabolomics and Proteomics (CF-MPC), Helmholtz Center Munich, German Center for Environmental Health GmbH, D-80939, Munich, Germany
| | - Gertrude Zisser
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Irina Grishkovskaya
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria
| | | | - Martin Vareka
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz, 8010, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz, 8010, Austria
| | - Stefanie M Hauck
- Core Facility Metabolomics and Proteomics (CF-MPC), Helmholtz Center Munich, German Center for Environmental Health GmbH, D-80939, Munich, Germany
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria.
| | - Helmut Bergler
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria.
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2
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An W, Yan Y, Ye K. High resolution landscape of ribosomal RNA processing and surveillance. Nucleic Acids Res 2024:gkae606. [PMID: 38994562 DOI: 10.1093/nar/gkae606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/21/2024] [Accepted: 06/28/2024] [Indexed: 07/13/2024] Open
Abstract
Ribosomal RNAs are processed in a complex pathway. We profiled rRNA processing intermediates in yeast at single-molecule and single-nucleotide levels with circularization, targeted amplification and deep sequencing (CircTA-seq), gaining significant mechanistic insights into rRNA processing and surveillance. The long form of the 5' end of 5.8S rRNA is converted to the short form and represents an intermediate of a unified processing pathway. The initial 3' end processing of 5.8S rRNA involves trimming by Rex1 and Rex2 and Trf4-mediated polyadenylation. The 3' end of 25S rRNA is formed by sequential digestion by four Rex proteins. Intermediates with an extended A1 site are generated during 5' degradation of aberrant 18S rRNA precursors. We determined precise polyadenylation profiles for pre-rRNAs and show that the degradation efficiency of polyadenylated 20S pre-rRNA critically depends on poly(A) lengths and degradation intermediates released from the exosome are often extensively re-polyadenylated.
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Affiliation(s)
- Weidong An
- Key Laboratory of RNA Science and Engineering, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yunxiao Yan
- Key Laboratory of RNA Science and Engineering, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Keqiong Ye
- Key Laboratory of RNA Science and Engineering, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Yang G, Schmid-Siegel M, Heissenberger C, Kos-Braun IC, Prechtl M, Meca-Laguna G, Rocha M, Wagner-Schrittwieser A, Pils V, Meixner B, Tav K, Hengstschläger M, Grillari J, Koš M, Schosserer M. 2'-O-ribose methylation levels of ribosomal RNA distinguish different types of growth arrest in human dermal fibroblasts. J Cell Sci 2024; 137:jcs261930. [PMID: 38345344 PMCID: PMC10911272 DOI: 10.1242/jcs.261930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 01/04/2024] [Indexed: 02/15/2024] Open
Abstract
The 2'-O-methylation (2'-O-Me) of ribosomal RNA (rRNA) shows plasticity that is potentially associated with cell phenotypes. We used RiboMeth-seq profiling to reveal growth arrest-specific 2'-O-Me patterns in primary human dermal fibroblasts from three different donors. We exposed cells to hydrogen peroxide to induce cellular senescence and to high cell densities to promote quiescence by contact inhibition. We compared both modes of cell cycle arrest to proliferating cells and could indeed distinguish these conditions by their overall 2'-O-Me patterns. Methylation levels at a small fraction of sites showed plasticity and correlated with the expression of specific small nucleolar RNAs (snoRNAs) but not with expression of fibrillarin. Moreover, we observed subtle senescence-associated alterations in ribosome biogenesis. Knockdown of the snoRNA SNORD87, which acts as a guide for modification of a hypermethylated position in non-proliferating cells, was sufficient to boost cell proliferation. Conversely, depletion of SNORD88A, SNORD88B and SNORD88C, which act as guides for modification of a hypomethylated site, caused decreased proliferation without affecting global protein synthesis or apoptosis. Taken together, our findings provide evidence that rRNA modifications can be used to distinguish and potentially influence specific growth phenotypes of primary cells.
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Affiliation(s)
- Guohuan Yang
- Biochemistry Center (BZH), Heidelberg University, 69120 Heidelberg, Germany
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Maximilian Schmid-Siegel
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
| | - Clemens Heissenberger
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | | | - Martina Prechtl
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Gabriel Meca-Laguna
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
| | - Marta Rocha
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
| | - Anja Wagner-Schrittwieser
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Vera Pils
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
| | - Barbara Meixner
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Koray Tav
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
| | - Markus Hengstschläger
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Johannes Grillari
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
- Ludwig Boltzmann Institute of Traumatology, 1200 Vienna, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Martin Koš
- Biochemistry Center (BZH), Heidelberg University, 69120 Heidelberg, Germany
| | - Markus Schosserer
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
- Christian Doppler Laboratory for Skin Multimodal Imaging of Aging and Senescence, 1090 Vienna, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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4
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Ma B, Liu H, Xiu ZH, Yang HH, Wang H, Wang Y, Tan BC. Defective kernel 58 encodes an Rrp15p domain-containing protein essential to ribosome biogenesis and seed development in maize. THE NEW PHYTOLOGIST 2024; 241:1662-1675. [PMID: 38058237 DOI: 10.1111/nph.19460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 11/08/2023] [Indexed: 12/08/2023]
Abstract
Ribosome biogenesis is a highly dynamic and orchestrated process facilitated by hundreds of ribosomal biogenesis factors and small nucleolar RNAs. While many of the advances are derived from studies in yeast, ribosome biogenesis remains largely unknown in plants despite its importance to plant growth and development. Through characterizing the maize (Zea mays) defective kernel and embryo-lethal mutant dek58, we show that DEK58 encodes an Rrp15p domain-containing protein with 15.3% identity to yeast Rrp15. Over-expression of DEK58 rescues the mutant phenotype. DEK58 is localized in the nucleolus. Ribosome profiling and RNA gel blot analyses show that the absence of DEK58 reduces ribosome assembly and impedes pre-rRNA processing, accompanied by the accumulation of nearly all the pre-rRNA processing intermediates and the production of an aberrant processing product P-25S*. DEK58 interacts with ZmSSF1, a maize homolog of the yeast Ssf1 in the 60S processome. DEK58 and ZmSSF1 interact with ZmCK2α, a putative component of the yeast UTP-C complex involved in the small ribosomal subunit processome. These results demonstrate that DEK58 is essential to seed development in maize. It functions in the early stage of pre-rRNA processing in ribosome biogenesis, possibly through interacting with ZmSSF1 and ZmCK2α in maize.
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Affiliation(s)
- Bing Ma
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Hui Liu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Zhi-Hui Xiu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Huan-Huan Yang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Hongqiu Wang
- National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yong Wang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Bao-Cai Tan
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
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5
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Vanden Broeck A, Klinge S. Principles of human pre-60 S biogenesis. Science 2023; 381:eadh3892. [PMID: 37410842 DOI: 10.1126/science.adh3892] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/20/2023] [Indexed: 07/08/2023]
Abstract
During the early stages of human large ribosomal subunit (60S) biogenesis, an ensemble of assembly factors establishes and fine-tunes the essential RNA functional centers of pre-60S particles by an unknown mechanism. Here, we report a series of cryo-electron microscopy structures of human nucleolar and nuclear pre-60S assembly intermediates at resolutions of 2.5 to 3.2 angstroms. These structures show how protein interaction hubs tether assembly factor complexes to nucleolar particles and how guanosine triphosphatases and adenosine triphosphatase couple irreversible nucleotide hydrolysis steps to the installation of functional centers. Nuclear stages highlight how a conserved RNA-processing complex, the rixosome, couples large-scale RNA conformational changes with pre-ribosomal RNA processing by the RNA degradation machinery. Our ensemble of human pre-60S particles provides a rich foundation with which to elucidate the molecular principles of ribosome formation.
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Affiliation(s)
- Arnaud Vanden Broeck
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY 10065, USA
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6
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Scull CE, Twa G, Zhang Y, Yang NJ, Hunter RN, Augelli-Szafran CE, Schneider DA. Small Molecule RBI2 Disrupts Ribosome Biogenesis through Pre-rRNA Depletion. Cancers (Basel) 2023; 15:3303. [PMID: 37444413 PMCID: PMC10340317 DOI: 10.3390/cancers15133303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Cancer cells are especially sensitive to perturbations in ribosome biogenesis as they rely on finely tuned protein homeostasis to facilitate their rapid growth and proliferation. While ribosome synthesis and cancer have a well-established relationship, ribosome biogenesis has only recently drawn interest as a cancer therapeutic target. In this study, we exploited the relationship between ribosome biogenesis and cancer cell proliferation by using a potent ribosome biogenesis inhibitor, RBI2 (Ribosome Biogenesis Inhibitor 2), to perturb cancer cell growth and viability. We demonstrate herein that RBI2 significantly decreases cell viability in malignant melanoma cells and breast cancer cell lines. Treatment with RBI2 dramatically and rapidly decreased ribosomal RNA (rRNA) synthesis, without affecting the occupancy of RNA polymerase I (Pol I) on the ribosomal DNA template. Next-generation RNA sequencing (RNA-seq) revealed that RBI2 and previously described ribosome biogenesis inhibitor CX-5461 induce distinct changes in the transcriptome. An investigation of the content of the pre-rRNAs through RT-qPCR revealed an increase in the polyadenylation of cellular rRNA after treatment with RBI2, constituting a known pathway by which rRNA degradation occurs. Northern blotting revealed that RBI2 does not appear to impair or alter rRNA processing. Collectively, these data suggest that RBI2 inhibits rRNA synthesis differently from other previously described ribosome biogenesis inhibitors, potentially acting through a novel pathway that upregulates the turnover of premature rRNAs.
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Affiliation(s)
- Catherine E. Scull
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Guy Twa
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yinfeng Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Naiheng J. Yang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | | | - David A. Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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7
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Broeck AV, Klinge S. Principles of human pre-60 S biogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532478. [PMID: 36993238 PMCID: PMC10054963 DOI: 10.1101/2023.03.14.532478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
During early stages of human large ribosomal subunit (60 S ) biogenesis, an ensemble of assembly factors establishes and fine-tunes the essential RNA functional centers of pre-60 S particles by an unknown mechanism. Here, we report a series of cryo-electron microscopy structures of human nucleolar and nuclear pre-60 S assembly intermediates at resolutions of 2.5-3.2 Ã…. These structures show how protein interaction hubs tether assembly factor complexes to nucleolar particles and how GTPases and ATPases couple irreversible nucleotide hydrolysis steps to the installation of functional centers. Nuclear stages highlight how a conserved RNA processing complex, the rixosome, couples large-scale RNA conformational changes to pre-rRNA processing by the RNA degradation machinery. Our ensemble of human pre-60 S particles provides a rich foundation to elucidate the molecular principles of ribosome formation. One-Sentence Summary High-resolution cryo-EM structures of human pre-60S particles reveal new principles of eukaryotic ribosome assembly.
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8
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Guerra-Slompo E, Cesaro G, Guimarães B, Zanchin N. Dissecting Trypanosoma brucei RRP44 function in the maturation of segmented ribosomal RNA using a regulated genetic complementation system. Nucleic Acids Res 2023; 51:396-419. [PMID: 36610751 PMCID: PMC9841430 DOI: 10.1093/nar/gkac1217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 11/29/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
Trypanosoma brucei belongs to a group of protozoans presenting fragmented large subunit rRNA. Its LSU rRNA equivalent to the 25S/28S rRNA of other eukaryotes is split into six fragments, requiring additional processing for removal of the extra spacer sequences. We have used a genetic complementation strategy to further investigate the T. brucei RRP44 nuclease in pre-rRNA maturation. TbRRP44 contains both a PIN and a RNB domain whose homologues are found in association with the exosome complex. We found that the exonucleolytic activity of the RNB domain as well as the physical presence of the PIN domain are essential for TbRRP44 function, while a catalytic site mutation in the PIN domain has no detectable effect on cell growth. A new endonucleolytic cleavage site in ITS1 was identified. In addition to the 5.8S rRNA 3'-end maturation, TbRRP44 is required for degradation of the excised 5'-ETS and for removal of part of ITS1 during maturation of the 18S rRNA 3'-end. TbRRP44 deficiency leads to accumulation of many LSU intermediate precursors, most of them not detected in control cells. TbRRP44 is also required for U3 snoRNA and spliced leader processing, indicating that TbRRP44 may have a wide role in RNA processing in T. brucei.
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Affiliation(s)
- Eloise Pavão Guerra-Slompo
- Carlos Chagas Institute, Oswaldo Cruz Foundation, FIOCRUZ, R. Prof. Algacyr Munhoz Mader 3775, 81350-010, Curitiba-PR, Brazil
| | - Giovanna Cesaro
- Carlos Chagas Institute, Oswaldo Cruz Foundation, FIOCRUZ, R. Prof. Algacyr Munhoz Mader 3775, 81350-010, Curitiba-PR, Brazil,Biochemistry Postgraduate Program, Federal University of Paraná, Curitiba-PR, Brazil
| | - Beatriz Gomes Guimarães
- Carlos Chagas Institute, Oswaldo Cruz Foundation, FIOCRUZ, R. Prof. Algacyr Munhoz Mader 3775, 81350-010, Curitiba-PR, Brazil,Biochemistry Postgraduate Program, Federal University of Paraná, Curitiba-PR, Brazil
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9
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Micic J, Rodríguez-Galán O, Babiano R, Fitzgerald F, Fernández-Fernández J, Zhang Y, Gao N, Woolford JL, de la Cruz J. Ribosomal protein eL39 is important for maturation of the nascent polypeptide exit tunnel and proper protein folding during translation. Nucleic Acids Res 2022; 50:6453-6473. [PMID: 35639884 PMCID: PMC9226512 DOI: 10.1093/nar/gkac366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 04/04/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022] Open
Abstract
During translation, nascent polypeptide chains travel from the peptidyl transferase center through the nascent polypeptide exit tunnel (NPET) to emerge from 60S subunits. The NPET includes portions of five of the six 25S/5.8S rRNA domains and ribosomal proteins uL4, uL22, and eL39. Internal loops of uL4 and uL22 form the constriction sites of the NPET and are important for both assembly and function of ribosomes. Here, we investigated the roles of eL39 in tunnel construction, 60S biogenesis, and protein synthesis. We show that eL39 is important for proper protein folding during translation. Consistent with a delay in processing of 27S and 7S pre-rRNAs, eL39 functions in pre-60S assembly during middle nucleolar stages. Our biochemical assays suggest the presence of eL39 in particles at these stages, although it is not visualized in them by cryo-electron microscopy. This indicates that eL39 takes part in assembly even when it is not fully accommodated into the body of pre-60S particles. eL39 is also important for later steps of assembly, rotation of the 5S ribonucleoprotein complex, likely through long range rRNA interactions. Finally, our data strongly suggest the presence of alternative pathways of ribosome assembly, previously observed in the biogenesis of bacterial ribosomal subunits.
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Affiliation(s)
- Jelena Micic
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Reyes Babiano
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Fiona Fitzgerald
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - José Fernández-Fernández
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Yunyang Zhang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - John L Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
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10
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Transcriptomic analysis of ribosome biogenesis and pre-rRNA processing during growth stress in Entamoeba histolytica. Exp Parasitol 2022; 239:108308. [PMID: 35718007 DOI: 10.1016/j.exppara.2022.108308] [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: 08/15/2021] [Revised: 05/27/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Abstract
Ribosome biogenesis, a multi-step process involving transcription, modification, folding and processing of rRNA, is the major consumer of cellular energy. It involves sequential assembly of ribosomal proteins (RP)s via more than 200 ribogenesis factors. Unlike model organisms where transcription of rRNA and RP genes slows down during stress, in Entamoeba histolytica, pre-rRNA synthesis continues, and unprocessed pre-rRNA accumulates. Northern hybridization from different spacer regions depicted the accumulation of unprocessed intermediates during stress. To gain insight into the vast repertoire of ribosome biogenesis factors and understand the major components playing role during stress we computationally identified ribosome biogenesis factors in E. histolytica. Of the ∼279 Saccharomyces cerevisiae proteins, we could only find 188 proteins in E. histolytica. Some of the proteins missing in E. histolytica were also missing in humans. A number of proteins represented by multiple genes in S. cerevisiae had a single copy in E. histolytica. Interestingly E. histolytica lacked mitochondrial ribosome biogenesis factors and had far less RNase components compared to S. cerevisiae. Transcriptomic studies revealed the differential regulation of ribosomal factors both in serum starved and RRP6 down-regulation conditions. These included the NEP1 and TSR3 proteins that chemically modify 18S-rRNA. Pre-rRNA precursors accumulate upon downregulation of the latter proteins in S. cerevisiae and humans. These data reveal the major factors that regulate pre-rRNA processing during stress in E. histolytica and provide the first complete repertoire of ribosome biogenesis factors in this early-branching protist.
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11
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Rehn M, Wenzel A, Frank AK, Schuster MB, Pundhir S, Jørgensen N, Vitting-Seerup K, Ge Y, Jendholm J, Michaut M, Schoof EM, Jensen TL, Rapin N, Sapio RT, Andersen KL, Lund AH, Solimena M, Holzenberger M, Pestov DG, Porse BT. PTBP1 promotes hematopoietic stem cell maintenance and red blood cell development by ensuring sufficient availability of ribosomal constituents. Cell Rep 2022; 39:110793. [PMID: 35545054 DOI: 10.1016/j.celrep.2022.110793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 03/14/2022] [Accepted: 04/15/2022] [Indexed: 11/18/2022] Open
Abstract
Ribosomopathies constitute a range of disorders associated with defective protein synthesis mainly affecting hematopoietic stem cells (HSCs) and erythroid development. Here, we demonstrate that deletion of poly-pyrimidine-tract-binding protein 1 (PTBP1) in the hematopoietic compartment leads to the development of a ribosomopathy-like condition. Specifically, loss of PTBP1 is associated with decreases in HSC self-renewal, erythroid differentiation, and protein synthesis. Consistent with its function as a splicing regulator, PTBP1 deficiency results in splicing defects in hundreds of genes, and we demonstrate that the up-regulation of a specific isoform of CDC42 partly mimics the protein-synthesis defect associated with loss of PTBP1. Furthermore, PTBP1 deficiency is associated with a marked defect in ribosome biogenesis and a selective reduction in the translation of mRNAs encoding ribosomal proteins. Collectively, this work identifies PTBP1 as a key integrator of ribosomal functions and highlights the broad functional repertoire of RNA-binding proteins.
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Affiliation(s)
- Matilda Rehn
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anne Wenzel
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anne-Katrine Frank
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Mikkel Bruhn Schuster
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Sachin Pundhir
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nanna Jørgensen
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | | | - Ying Ge
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Johan Jendholm
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Magali Michaut
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Erwin M Schoof
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; DTU Bioengineering, Danish Technical University, 2800 Kgs. Lyngby, Denmark
| | - Tanja Lyholm Jensen
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolas Rapin
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Russell T Sapio
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | | | - Anders H Lund
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark
| | - Michele Solimena
- Molecular Diabetology, University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany; Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Martin Holzenberger
- Sorbonne University, INSERM, Research Center Saint-Antoine, CRSA, 75012 Paris, France
| | - Dimitri G Pestov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Bo Torben Porse
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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12
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Sailer C, Jansen J, Sekulski K, Cruz VE, Erzberger JP, Stengel F. A comprehensive landscape of 60S ribosome biogenesis factors. Cell Rep 2022; 38:110353. [PMID: 35139378 PMCID: PMC8884084 DOI: 10.1016/j.celrep.2022.110353] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/02/2021] [Accepted: 01/19/2022] [Indexed: 01/03/2023] Open
Abstract
Eukaryotic ribosome biogenesis is facilitated and regulated by numerous ribosome biogenesis factors (RBFs). High-resolution cryoelectron microscopy (cryo-EM) maps have defined the molecular interactions of RBFs during maturation, but many transient and dynamic interactions, particularly during early assembly, remain uncharacterized. Using quantitative proteomics and crosslinking coupled to mass spectrometry (XL-MS) data from an extensive set of pre-ribosomal particles, we derive a comprehensive and time-resolved interaction map of RBF engagement during 60S maturation. We localize 22 previously unmapped RBFs to specific biogenesis intermediates and validate our results by mapping the catalytic activity of the methyltransferases Bmt2 and Rcm1 to their predicted nucleolar 60S intermediates. Our analysis reveals the interaction sites for the RBFs Noc2 and Ecm1 and elucidates the interaction map and timing of 60S engagement by the DEAD-box ATPases Dbp9 and Dbp10. Our data provide a powerful resource for future studies of 60S ribosome biogenesis. In this study, Sailer et al. generate a comprehensive and precise timeline of ribosome biogenesis factor (RBF) engagement during 60S maturation and localize previously unmapped RBFs in the yeast Saccharomyces cerevisiae. Overall, their data represent an essential resource for future structural studies of large subunit ribosome biogenesis.
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Affiliation(s)
- Carolin Sailer
- Department of Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany
| | - Jasmin Jansen
- Department of Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany
| | - Kamil Sekulski
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, 5323 Harry Hines Boulevard, Dallas, TX 75390-8816, USA
| | - Victor E Cruz
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, 5323 Harry Hines Boulevard, Dallas, TX 75390-8816, USA
| | - Jan P Erzberger
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, 5323 Harry Hines Boulevard, Dallas, TX 75390-8816, USA.
| | - Florian Stengel
- Department of Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrae 10, 78457 Konstanz, Germany.
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13
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Szaflarski W, Leśniczak-Staszak M, Sowiński M, Ojha S, Aulas A, Dave D, Malla S, Anderson P, Ivanov P, Lyons SM. Early rRNA processing is a stress-dependent regulatory event whose inhibition maintains nucleolar integrity. Nucleic Acids Res 2022; 50:1033-1051. [PMID: 34928368 PMCID: PMC8789083 DOI: 10.1093/nar/gkab1231] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/24/2021] [Accepted: 12/02/2021] [Indexed: 01/20/2023] Open
Abstract
The production of ribosomes is an energy-intensive process owing to the intricacy of these massive macromolecular machines. Each human ribosome contains 80 ribosomal proteins and four non-coding RNAs. Accurate assembly requires precise regulation of protein and RNA subunits. In response to stress, the integrated stress response (ISR) rapidly inhibits global translation. How rRNA is coordinately regulated with the rapid inhibition of ribosomal protein synthesis is not known. Here, we show that stress specifically inhibits the first step of rRNA processing. Unprocessed rRNA is stored within the nucleolus, and when stress resolves, it re-enters the ribosome biogenesis pathway. Retention of unprocessed rRNA within the nucleolus aids in the maintenance of this organelle. This response is independent of the ISR or inhibition of cellular translation but is independently regulated. Failure to coordinately control ribosomal protein translation and rRNA production results in nucleolar fragmentation. Our study unveils how the rapid translational shut-off in response to stress coordinates with rRNA synthesis production to maintain nucleolar integrity.
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Affiliation(s)
- Witold Szaflarski
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Marta Leśniczak-Staszak
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Mateusz Sowiński
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Sandeep Ojha
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Anaïs Aulas
- Predictive Oncology Laboratory, Cancer Research Center of Marseille (CRCM), Inserm U1068, CNRS UMR7258, Institut Paoli-Calmettes, Aix Marseille Université, Marseille, France
| | - Dhwani Dave
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
| | - Sulochan Malla
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Paul Anderson
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Shawn M Lyons
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
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14
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Mo C, Xie C, Wang G, Tian T, Liu J, Zhu C, Xiao X, Xiao Y. Cyclophilin acts as a ribosome biogenesis factor by chaperoning the ribosomal protein (PlRPS15) in filamentous fungi. Nucleic Acids Res 2021; 49:12358-12376. [PMID: 34792171 PMCID: PMC8643696 DOI: 10.1093/nar/gkab1102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 11/14/2022] Open
Abstract
The rapid transport of ribosomal proteins (RPs) into the nucleus and their efficient assembly into pre-ribosomal particles are prerequisites for ribosome biogenesis. Proteins that act as dedicated chaperones for RPs to maintain their stability and facilitate their assembly have not been identified in filamentous fungi. PlCYP5 is a nuclear cyclophilin in the nematophagous fungus Purpureocillium lilacinum, whose expression is up-regulated during abiotic stress and nematode egg-parasitism. Here, we found that PlCYP5 co-translationally interacted with the unassembled small ribosomal subunit protein, PlRPS15 (uS19). PlRPS15 contained an eukaryote-specific N-terminal extension that mediated the interaction with PlCYP5. PlCYP5 increased the solubility of PlRPS15 independent of its catalytic peptide-prolyl isomerase function and supported the integration of PlRPS15 into pre-ribosomes. Consistently, the phenotypes of the PlCYP5 loss-of-function mutant were similar to those of the PlRPS15 knockdown mutant (e.g. growth and ribosome biogenesis defects). PlCYP5 homologs in Arabidopsis thaliana, Homo sapiens, Schizosaccharomyces pombe, Sclerotinia sclerotiorum, Botrytis cinerea and Metarhizium anisopliae were identified. Notably, PlCYP5-PlRPS15 homologs from three filamentous fungi interacted with each other but not those from other species. In summary, our data disclosed a unique dedicated chaperone system for RPs by cyclophilin in filamentous fungi.
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Affiliation(s)
- Chenmi Mo
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Chong Xie
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Gaofeng Wang
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Tian Tian
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Juan Liu
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Chunxiao Zhu
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Xueqiong Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.,Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Yannong Xiao
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
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15
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Non-Coding, RNAPII-Dependent Transcription at the Promoters of rRNA Genes Regulates Their Chromatin State in S. cerevisiae. Noncoding RNA 2021; 7:ncrna7030041. [PMID: 34287362 PMCID: PMC8293398 DOI: 10.3390/ncrna7030041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 12/22/2022] Open
Abstract
Pervasive transcription is widespread in eukaryotes, generating large families of non-coding RNAs. Such pervasive transcription is a key player in the regulatory pathways controlling chromatin state and gene expression. Here, we describe long non-coding RNAs generated from the ribosomal RNA gene promoter called UPStream-initiating transcripts (UPS). In yeast, rDNA genes are organized in tandem repeats in at least two different chromatin states, either transcribed and largely depleted of nucleosomes (open) or assembled in regular arrays of nucleosomes (closed). The production of UPS transcripts by RNA Polymerase II from endogenous rDNA genes was initially documented in mutants defective for rRNA production by RNA polymerase I. We show here that UPS are produced in wild-type cells from closed rDNA genes but are hidden within the enormous production of rRNA. UPS levels are increased when rDNA chromatin states are modified at high temperatures or entering/leaving quiescence. We discuss their role in the regulation of rDNA chromatin states and rRNA production.
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16
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Black JJ, Johnson AW. Genetics animates structure: leveraging genetic interactions to study the dynamics of ribosome biogenesis. Curr Genet 2021; 67:729-738. [PMID: 33844044 DOI: 10.1007/s00294-021-01187-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 11/26/2022]
Abstract
The assembly of eukaryotic ribosomes follows an assembly line-like pathway in which numerous trans-acting biogenesis factors act on discrete pre-ribosomal intermediates to progressively shape the nascent subunits into their final functional architecture. Recent advances in cryo-electron microscopy have led to high-resolution structures of many pre-ribosomal intermediates; however, these static snapshots do not capture the dynamic transitions between these intermediates. To this end, molecular genetics can be leveraged to reveal how the biogenesis factors drive these dynamic transitions. Here, we briefly review how we recently used the deletion of BUD23 (bud23∆) to understand its role in the assembly of the ribosomal small subunit. The strong growth defect of bud23∆ mutants places a selective pressure on yeast cells for the occurrence of extragenic suppressors that define a network of functional interactions among biogenesis factors. Mapping these suppressing mutations to recently published structures of pre-ribosomal complexes allowed us to contextualize these suppressing mutations and derive a detailed model in which Bud23 promotes a critical transition event to facilitate folding of the central pseudoknot of the small subunit. This mini-review highlights how genetics can be used to understand the dynamics of complex structures, such as the maturing ribosome.
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Affiliation(s)
- Joshua J Black
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Arlen W Johnson
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
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17
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Najmi SM, Schneider DA. Quorum sensing regulates rRNA synthesis in Saccharomyces cerevisiae. Gene 2021; 776:145442. [PMID: 33482283 DOI: 10.1016/j.gene.2021.145442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/04/2021] [Accepted: 01/13/2021] [Indexed: 11/18/2022]
Abstract
Ribosome biogenesis requires the concerted activities of three nuclear RNA polymerases, (Pols) I, II, and III, to produce 25S, 18S and 5.8S ribosomal RNA (rRNA), messenger RNA (mRNA) encoding ribosomal proteins, and the 5S rRNA, respectively. The rRNA is processed and modified before being assembled with ribosomal proteins to produce a ribosome. Ribosome biogenesis requires extensive energetic investment by the cell, so it is critical that this process is tightly regulated in accord with cellular growth potential. Previous work revealed that rRNA synthesis in Saccharomyces cerevisiae is repressed prior to the cells shift from active growth (log phase) to limited/static growth (stationary phase). The mechanism(s) by which cells anticipate imminent stationary phase are unknown. In this study, we demonstrate that growing cells produce one or more compounds that accumulate in the growth medium, and that this compound induces repression of rRNA synthesis. When cells encounter this compound, rRNA synthesis is rapidly repressed. We further show that subunits of Pols I and II are degraded during the transition from log to stationary phase growth, but this degradation does not account for the observed repression of rRNA synthesis. Interestingly, repression of rRNA synthesis by spent media requires the nuclear exosome, implying that spent media stimulates rapid rRNA degradation. Together, these data suggest that yeast use quorum sensing to regulate rRNA synthesis in anticipation of high cell density in stationary phase.
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Affiliation(s)
- Saman M Najmi
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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18
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Martínez-Fernández V, Cuevas-Bermúdez A, Gutiérrez-Santiago F, Garrido-Godino AI, Rodríguez-Galán O, Jordán-Pla A, Lois S, Triviño JC, de la Cruz J, Navarro F. Prefoldin-like Bud27 influences the transcription of ribosomal components and ribosome biogenesis in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2020; 26:1360-1379. [PMID: 32503921 PMCID: PMC7491330 DOI: 10.1261/rna.075507.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/28/2020] [Indexed: 05/08/2023]
Abstract
Understanding the functional connection that occurs for the three nuclear RNA polymerases to synthesize ribosome components during the ribosome biogenesis process has been the focal point of extensive research. To preserve correct homeostasis on the production of ribosomal components, cells might require the existence of proteins that target a common subunit of these RNA polymerases to impact their respective activities. This work describes how the yeast prefoldin-like Bud27 protein, which physically interacts with the Rpb5 common subunit of the three RNA polymerases, is able to modulate the transcription mediated by the RNA polymerase I, likely by influencing transcription elongation, the transcription of the RNA polymerase III, and the processing of ribosomal RNA. Bud27 also regulates both RNA polymerase II-dependent transcription of ribosomal proteins and ribosome biogenesis regulon genes, likely by occupying their DNA ORFs, and the processing of the corresponding mRNAs. With RNA polymerase II, this association occurs in a transcription rate-dependent manner. Our data also indicate that Bud27 inactivation alters the phosphorylation kinetics of ribosomal protein S6, a readout of TORC1 activity. We conclude that Bud27 impacts the homeostasis of the ribosome biogenesis process by regulating the activity of the three RNA polymerases and, in this way, the synthesis of ribosomal components. This quite likely occurs through a functional connection of Bud27 with the TOR signaling pathway.
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Affiliation(s)
- Verónica Martínez-Fernández
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
| | - Abel Cuevas-Bermúdez
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
| | - Francisco Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
| | - Ana I Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain
- Departamento de Genética, Universidad de Sevilla, E-41012 Seville, Spain
| | - Antonio Jordán-Pla
- ERI Biotecmed, Facultad de Biológicas, Universitat de València, E-46100 Burjassot, Valencia, Spain
| | - Sergio Lois
- Sistemas Genómicos. Ronda de Guglielmo Marconi, 6, 46980 Paterna, Valencia, Spain
| | - Juan C Triviño
- Sistemas Genómicos. Ronda de Guglielmo Marconi, 6, 46980 Paterna, Valencia, Spain
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain
- Departamento de Genética, Universidad de Sevilla, E-41012 Seville, Spain
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
- Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071, Jaén, Spain
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19
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From Snapshots to Flipbook-Resolving the Dynamics of Ribosome Biogenesis with Chemical Probes. Int J Mol Sci 2020; 21:ijms21082998. [PMID: 32340379 PMCID: PMC7215809 DOI: 10.3390/ijms21082998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 12/27/2022] Open
Abstract
The synthesis of ribosomes is one of the central and most resource demanding processes in each living cell. As ribosome biogenesis is tightly linked with the regulation of the cell cycle, perturbation of ribosome formation can trigger severe diseases, including cancer. Eukaryotic ribosome biogenesis starts in the nucleolus with pre-rRNA transcription and the initial assembly steps, continues in the nucleoplasm and is finished in the cytoplasm. From start to end, this process is highly dynamic and finished within few minutes. Despite the tremendous progress made during the last decade, the coordination of the individual maturation steps is hard to unravel by a conventional methodology. In recent years small molecular compounds were identified that specifically block either rDNA transcription or distinct steps within the maturation pathway. As these inhibitors diffuse into the cell rapidly and block their target proteins within seconds, they represent excellent tools to investigate ribosome biogenesis. Here we review how the inhibitors affect ribosome biogenesis and discuss how these effects can be interpreted by taking the complex self-regulatory mechanisms of the pathway into account. With this we want to highlight the potential of low molecular weight inhibitors to approach the dynamic nature of the ribosome biogenesis pathway.
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20
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Braun CM, Hackert P, Schmid CE, Bohnsack MT, Bohnsack KE, Perez-Fernandez J. Pol5 is required for recycling of small subunit biogenesis factors and for formation of the peptide exit tunnel of the large ribosomal subunit. Nucleic Acids Res 2020; 48:405-420. [PMID: 31745560 PMCID: PMC7145529 DOI: 10.1093/nar/gkz1079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/29/2019] [Accepted: 11/04/2019] [Indexed: 01/24/2023] Open
Abstract
More than 200 assembly factors (AFs) are required for the production of ribosomes in yeast. The stepwise association and dissociation of these AFs with the pre-ribosomal subunits occurs in a hierarchical manner to ensure correct maturation of the pre-rRNAs and assembly of the ribosomal proteins. Although decades of research have provided a wealth of insights into the functions of many AFs, others remain poorly characterized. Pol5 was initially classified with B-type DNA polymerases, however, several lines of evidence indicate the involvement of this protein in ribosome assembly. Here, we show that depletion of Pol5 affects the processing of pre-rRNAs destined for the both the large and small subunits. Furthermore, we identify binding sites for Pol5 in the 5' external transcribed spacer and within domain III of the 25S rRNA sequence. Consistent with this, we reveal that Pol5 is required for recruitment of ribosomal proteins that form the polypeptide exit tunnel in the LSU and that depletion of Pol5 impairs the release of 5' ETS fragments from early pre-40S particles. The dual functions of Pol5 in 60S assembly and recycling of pre-40S AFs suggest that this factor could contribute to ensuring the stoichiometric production of ribosomal subunits.
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Affiliation(s)
- Christina M Braun
- Department of Biochemistry III, University of Regensburg, Universitätstrasse 31, 93053 Regensburg, Germany
| | - Philipp Hackert
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Catharina E Schmid
- Department of Biochemistry III, University of Regensburg, Universitätstrasse 31, 93053 Regensburg, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.,Göttingen Center for Molecular Biosciences, Georg-August University, Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Jorge Perez-Fernandez
- Department of Biochemistry III, University of Regensburg, Universitätstrasse 31, 93053 Regensburg, Germany
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21
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Smekalova EM, Gerashchenko MV, O'Connor PBF, Whittaker CA, Kauffman KJ, Fefilova AS, Zatsepin TS, Bogorad RL, Baranov PV, Langer R, Gladyshev VN, Anderson DG, Koteliansky V. In Vivo RNAi-Mediated eIF3m Knockdown Affects Ribosome Biogenesis and Transcription but Has Limited Impact on mRNA-Specific Translation. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 19:252-266. [PMID: 31855834 PMCID: PMC6926209 DOI: 10.1016/j.omtn.2019.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/20/2019] [Accepted: 11/05/2019] [Indexed: 12/19/2022]
Abstract
Translation is an essential biological process, and dysregulation is associated with a range of diseases including ribosomopathies, diabetes, and cancer. Here, we examine translation dysregulation in vivo using RNAi to knock down the m-subunit of the translation initiation factor eIF3 in the mouse liver. Transcriptome sequencing, ribosome profiling, whole proteome, and phosphoproteome analyses show that eIF3m deficiency leads to the transcriptional response and changes in cellular translation that yield few detectable differences in the translation of particular mRNAs. The transcriptional response fell into two main categories: ribosome biogenesis (increased transcription of ribosomal proteins) and cell metabolism (alterations in lipid, amino acid, nucleic acid, and drug metabolism). Analysis of ribosome biogenesis reveals inhibition of rRNA processing, highlighting decoupling of rRNA synthesis and ribosomal protein gene transcription in response to eIF3m knockdown. Interestingly, a similar reduction in eIF3m protein levels is associated with induction of the mTOR pathway in vitro but not in vivo. Overall, this work highlights the utility of a RNAi-based in vivo approach for studying the regulation of mammalian translation in vivo.
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Affiliation(s)
- Elena M Smekalova
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Maxim V Gerashchenko
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Patrick B F O'Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 YN60, Ireland
| | - Charles A Whittaker
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Kevin J Kauffman
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Anna S Fefilova
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 121205, Russia
| | - Timofei S Zatsepin
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 121205, Russia; Department of Chemistry and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Roman L Bogorad
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 YN60, Ireland; Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow 117997, Russia
| | - Robert Langer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA; Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Daniel G Anderson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA; Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Victor Koteliansky
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 121205, Russia.
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22
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Ramos-Sáenz A, González-Álvarez D, Rodríguez-Galán O, Rodríguez-Gil A, Gaspar SG, Villalobo E, Dosil M, de la Cruz J. Pol5 is an essential ribosome biogenesis factor required for 60S ribosomal subunit maturation in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2019; 25:1561-1575. [PMID: 31413149 PMCID: PMC6795146 DOI: 10.1261/rna.072116.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
In Saccharomyces cerevisiae, more than 250 trans-acting factors are involved in the maturation of 40S and 60S ribosomal subunits. The expression of most of these factors is transcriptionally coregulated to ensure correct ribosome production under a wide variety of environmental and intracellular conditions. Here, we identified the essential nucleolar Pol5 protein as a novel trans-acting factor required for the synthesis of 60S ribosomal subunits. Pol5 weakly and/or transiently associates with early to medium pre-60S ribosomal particles. Depletion of and temperature-sensitive mutations in Pol5 result in a deficiency of 60S ribosomal subunits and accumulation of half-mer polysomes. Both processing of 27SB pre-rRNA to mature 25S rRNA and release of pre-60S ribosomal particles from the nucle(ol)us to the cytoplasm are impaired in the Pol5-depleted strain. Moreover, we identified the genes encoding ribosomal proteins uL23 and eL27A as multicopy suppressors of the slow growth of a temperature-sensitive pol5 mutant. These results suggest that Pol5 could function in ensuring the correct folding of 25S rRNA domain III; thus, favoring the correct assembly of these two ribosomal proteins at their respective binding sites into medium pre-60S ribosomal particles. Pol5 is homologous to the human tumor suppressor Myb-binding protein 1A (MYBBP1A). However, expression of MYBBP1A failed to complement the lethal phenotype of a pol5 null mutant strain though interfered with 60S ribosomal subunit biogenesis.
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Affiliation(s)
- Ana Ramos-Sáenz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Daniel González-Álvarez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Alfonso Rodríguez-Gil
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
| | - Sonia G Gaspar
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Centro de Investigación Biomédica en Red en Cáncer (CIBERONC), CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
| | - Eduardo Villalobo
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Mercedes Dosil
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Centro de Investigación Biomédica en Red en Cáncer (CIBERONC), CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, E-37007, Salamanca, Spain
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
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23
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Khoshnevis S, Dreggors RE, Hoffmann TFR, Ghalei H. A conserved Bcd1 interaction essential for box C/D snoRNP biogenesis. J Biol Chem 2019; 294:18360-18371. [PMID: 31537647 DOI: 10.1074/jbc.ra119.010222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/17/2019] [Indexed: 12/22/2022] Open
Abstract
Precise modification and processing of rRNAs are required for the production of ribosomes and accurate translation of proteins. Small nucleolar ribonucleoproteins (snoRNPs) guide the folding, modification, and processing of rRNAs and are thus critical for all eukaryotic cells. Bcd1, an essential zinc finger HIT protein functionally conserved in eukaryotes, has been implicated as an early regulator for biogenesis of box C/D snoRNPs and controls steady-state levels of box C/D snoRNAs through an unknown mechanism. Using a combination of genetic and biochemical approaches, here we found a conserved N-terminal motif in Bcd1 from Saccharomyces cerevisiae that is required for interactions with box C/D snoRNAs and the core snoRNP protein, Snu13. We show that both the Bcd1-snoRNA and Bcd1-Snu13 interactions are critical for snoRNP assembly and ribosome biogenesis. Our results provide mechanistic insight into Bcd1 interactions that likely control the early steps of snoRNP maturation and contribute to the essential role of this protein in maintaining the steady-state levels of snoRNAs in the cell.
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Affiliation(s)
- Sohail Khoshnevis
- Department of Biology, Emory University, Atlanta, Georgia 30322; Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - R Elizabeth Dreggors
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322; Graduate Program in Biochemistry, Cell and Developmental Biology (BCDB), Emory University, Atlanta, Georgia 30322
| | - Tobias F R Hoffmann
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Homa Ghalei
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322; Graduate Program in Biochemistry, Cell and Developmental Biology (BCDB), Emory University, Atlanta, Georgia 30322.
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24
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Matos-Perdomo E, Machín F. Nucleolar and Ribosomal DNA Structure under Stress: Yeast Lessons for Aging and Cancer. Cells 2019; 8:cells8080779. [PMID: 31357498 PMCID: PMC6721496 DOI: 10.3390/cells8080779] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023] Open
Abstract
Once thought a mere ribosome factory, the nucleolus has been viewed in recent years as an extremely sensitive gauge of diverse cellular stresses. Emerging concepts in nucleolar biology include the nucleolar stress response (NSR), whereby a series of cell insults have a special impact on the nucleolus. These insults include, among others, ultra-violet radiation (UV), nutrient deprivation, hypoxia and thermal stress. While these stresses might influence nucleolar biology directly or indirectly, other perturbances whose origin resides in the nucleolar biology also trigger nucleolar and systemic stress responses. Among the latter, we find mutations in nucleolar and ribosomal proteins, ribosomal RNA (rRNA) processing inhibitors and ribosomal DNA (rDNA) transcription inhibition. The p53 protein also mediates NSR, leading ultimately to cell cycle arrest, apoptosis, senescence or differentiation. Hence, NSR is gaining importance in cancer biology. The nucleolar size and ribosome biogenesis, and how they connect with the Target of Rapamycin (TOR) signalling pathway, are also becoming important in the biology of aging and cancer. Simple model organisms like the budding yeast Saccharomyces cerevisiae, easy to manipulate genetically, are useful in order to study nucleolar and rDNA structure and their relationship with stress. In this review, we summarize the most important findings related to this topic.
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Affiliation(s)
- Emiliano Matos-Perdomo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Postgrado, Universidad de La Laguna, 38200 Tenerife, Spain
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain.
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 Tenerife, Spain.
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, 35450 Santa María de Guía, Gran Canaria, Spain.
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25
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Scull CE, Schneider DA. Coordinated Control of rRNA Processing by RNA Polymerase I. Trends Genet 2019; 35:724-733. [PMID: 31358304 DOI: 10.1016/j.tig.2019.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/25/2019] [Accepted: 07/01/2019] [Indexed: 11/19/2022]
Abstract
Ribosomal RNA (rRNA) is co- and post-transcriptionally processed into active ribosomes. This process is dynamically regulated by direct covalent modifications of the polymerase that synthesizes the rRNA, RNA polymerase I (Pol I), and by interactions with cofactors that influence initiation, elongation, and termination activities of Pol I. The rate of transcription elongation by Pol I directly influences processing of nascent rRNA, and changes in Pol I transcription rate result in alternative rRNA processing events that lead to cellular signaling alterations and stress. It is clear that in divergent species, there exists robust organization of nascent rRNA processing events during transcription elongation. This review evaluates the current state of our understanding of the complex relationship between transcription elongation and rRNA processing.
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Affiliation(s)
- Catherine E Scull
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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26
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Gallagher JEG. Proteins and RNA sequences required for the transition of the t-Utp complex into the SSU processome. FEMS Yeast Res 2019; 19:5184469. [PMID: 30445532 DOI: 10.1093/femsyr/foy120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 11/12/2018] [Indexed: 12/20/2022] Open
Abstract
Ribosomes are synthesized by large ribonucleoprotein complexes cleaving and properly assembling highly structured rRNAs with ribosomal proteins. Transcription and processing of pre-rRNAs are linked by the transcription-Utp sub-complex (t-Utps), a sub-complex of the small subunit (SSU) processome and prompted the investigations for the requirements of t-Utp formation and transition into the SSU processome. The rDNA promoter, the first 44 nucleotides of the 5΄ETS, and active transcription by pol I were sufficient to recruit the t-Utps to the rDNA. Pol5, accessory factor, dissociated as t-Utps matured into the UtpA complex which permitted later recruitment of the UtpB, U3 snoRNP and the Mpp10 complex into the SSU processome. The t-Utp complex associated with short RNAs 121 and 138 nucleotides long transcribed from the 5΄ETS. These transcripts were not present when pol II transcribed the rDNA or in nondividing cells. Depletion of a t-Utp, but not of other SSU processome components led to decreased levels of the short transcripts. However, ectopic expression of the short transcripts slowed the growth of yeast with impaired rDNA transcription. These results provide insight into how transcription of the rRNA primes the assemble of t-Utp complex with the pre-rRNA into the UtpA complex and the later association of SSU processome components.
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27
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Awad D, Prattes M, Kofler L, Rössler I, Loibl M, Pertl M, Zisser G, Wolinski H, Pertschy B, Bergler H. Inhibiting eukaryotic ribosome biogenesis. BMC Biol 2019; 17:46. [PMID: 31182083 PMCID: PMC6558755 DOI: 10.1186/s12915-019-0664-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/14/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Ribosome biogenesis is a central process in every growing cell. In eukaryotes, it requires more than 250 non-ribosomal assembly factors, most of which are essential. Despite this large repertoire of potential targets, only very few chemical inhibitors of ribosome biogenesis are known so far. Such inhibitors are valuable tools to study this highly dynamic process and elucidate mechanistic details of individual maturation steps. Moreover, ribosome biogenesis is of particular importance for fast proliferating cells, suggesting its inhibition could be a valid strategy for treatment of tumors or infections. RESULTS We systematically screened ~ 1000 substances for inhibitory effects on ribosome biogenesis using a microscopy-based screen scoring ribosomal subunit export defects. We identified 128 compounds inhibiting maturation of either the small or the large ribosomal subunit or both. Northern blot analysis demonstrates that these inhibitors cause a broad spectrum of different rRNA processing defects. CONCLUSIONS Our findings show that the individual inhibitors affect a wide range of different maturation steps within the ribosome biogenesis pathway. Our results provide for the first time a comprehensive set of inhibitors to study ribosome biogenesis by chemical inhibition of individual maturation steps and establish the process as promising druggable pathway for chemical intervention.
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Affiliation(s)
- Dominik Awad
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
- Present address: Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Michael Prattes
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Lisa Kofler
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Ingrid Rössler
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Mathias Loibl
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Melanie Pertl
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Gertrude Zisser
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria
| | - Brigitte Pertschy
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria.
| | - Helmut Bergler
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/EG, A-8010, Graz, Austria.
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28
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Albert B, Kos-Braun IC, Henras AK, Dez C, Rueda MP, Zhang X, Gadal O, Kos M, Shore D. A ribosome assembly stress response regulates transcription to maintain proteome homeostasis. eLife 2019; 8:45002. [PMID: 31124783 PMCID: PMC6579557 DOI: 10.7554/elife.45002] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/23/2019] [Indexed: 12/13/2022] Open
Abstract
Ribosome biogenesis is a complex and energy-demanding process requiring tight coordination of ribosomal RNA (rRNA) and ribosomal protein (RP) production. Given the extremely high level of RP synthesis in rapidly growing cells, alteration of any step in the ribosome assembly process may impact growth by leading to proteotoxic stress. Although the transcription factor Hsf1 has emerged as a central regulator of proteostasis, how its activity is coordinated with ribosome biogenesis is unknown. Here, we show that arrest of ribosome biogenesis in the budding yeast Saccharomyces cerevisiae triggers rapid activation of a highly specific stress pathway that coordinately upregulates Hsf1 target genes and downregulates RP genes. Activation of Hsf1 target genes requires neo-synthesis of RPs, which accumulate in an insoluble fraction and presumably titrate a negative regulator of Hsf1, the Hsp70 chaperone. RP aggregation is also coincident with that of the RP gene activator Ifh1, a transcription factor that is rapidly released from RP gene promoters. Our data support a model in which the levels of newly synthetized RPs, imported into the nucleus but not yet assembled into ribosomes, work to continuously balance Hsf1 and Ifh1 activity, thus guarding against proteotoxic stress during ribosome assembly. When yeast cells are growing at top speed, they can make 2,000 new ribosomes every minute. These enormous molecular assemblies are the protein-making machines of the cell. Building new ribosomes is one of the most energy-demanding parts of cell growth and, if the process goes wrong, the results can be catastrophic. The proteins that make up the ribosomes themselves are sticky. Left unattended, they start to form toxic clumps inside the compartment that houses most of the cell’s DNA, the nucleus. A protein called Heat shock factor 1, or Hsf1 for short, plays an important role in the cell's quality control systems. It helps to manage sticky proteins by switching on genes that break down protein clumps and prevent new clumps from forming. Hsf1 levels start to rise whenever cells are struggling to keep up with protein production. If it is half-finished ribosomes that are causing the problem, cells can stop making ribosome proteins. The protein in charge of this in yeast is Ifh1. It is a transcription factor that sits at the front of the genes for ribosome proteins, switching them on. When yeast cells get stressed, Ifh1 drops away from the genes within minutes, switching them off again. Yet how this happens, and how it links to Hsf1, is a mystery. To start to provide some answers, Albert et al. disrupted the production of ribosomes in yeast cells and examined the consequences. This revealed a new rescue response, that they named the “ribosome assembly stress response”. Both Hsf1 and Ifh1 are sensitive to the build-up of unfinished ribosomes in the nucleus. As expected, Hsf1 activated when ribosome proteins started to build up, and switched on the genes needed to manage the protein clumps. The effect on Isfh1, however, was unexpected. When the unassembled ribosome proteins started to build up, it was the clumps themselves that pulled the Ifh1 proteins off the genes. The unassembled ribosomes proteins seemed to be stopping their own production. Low levels of clumped ribosome proteins in the nuclei of unstressed cells also helped to keep Hsf1 active and pull Ifh1 off the ribosome genes. It is possible that this provides continual protection against a toxic protein build-up. These findings are not only important for understanding yeast cells; cancer cells also need to produce ribosomes at a very high rate to sustain their rapid growth. They too might be prone to stresses that interrupt their ribosome assembly. As such, understanding more about this process could one day lead to new therapies to target cancer cells.
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Affiliation(s)
- Benjamin Albert
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), Geneva, Switzerland
| | | | - Anthony K Henras
- Centre de Biologie Intégrative, Université Paul Sabatier, Toulouse, France
| | - Christophe Dez
- Centre de Biologie Intégrative, Université Paul Sabatier, Toulouse, France
| | - Maria Paula Rueda
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), Geneva, Switzerland
| | - Xu Zhang
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), Geneva, Switzerland
| | - Olivier Gadal
- Centre de Biologie Intégrative, Université Paul Sabatier, Toulouse, France
| | - Martin Kos
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - David Shore
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), Geneva, Switzerland
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29
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Proteins that physically interact with the phosphatase Cdc14 in Candida albicans have diverse roles in the cell cycle. Sci Rep 2019; 9:6258. [PMID: 31000734 PMCID: PMC6472416 DOI: 10.1038/s41598-019-42530-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 03/29/2019] [Indexed: 01/08/2023] Open
Abstract
The chromosome complement of the human fungal pathogen Candida albicans is unusually unstable, suggesting that the process of nuclear division is error prone. The Cdc14 phosphatase plays a key role in organising the intricate choreography of mitosis and cell division. In order to understand the role of Cdc14 in C. albicans we used quantitative proteomics to identify proteins that physically interact with Cdc14. To distinguish genuine Cdc14-interactors from proteins that bound non-specifically to the affinity matrix, we used a substrate trapping mutant combined with mass spectrometry analysis using Stable Isotope Labelling with Amino Acids in Cell Culture (SILAC). The results identified 126 proteins that interact with Cdc14 of which 80% have not previously been identified as Cdc14 interactors in C. albicans or S. cerevisiae. In this set, 55 proteins are known from previous research in S. cerevisiae and S. pombe to play roles in the cell cycle, regulating the attachment of the mitotic spindle to kinetochores, mitotic exit, cytokinesis, licensing of DNA replication by re-activating pre-replication complexes, and DNA repair. Five Cdc14-interacting proteins with previously unknown functions localised to the Spindle Pole Bodies (SPBs). Thus, we have greatly increased the number of proteins that physically interact with Cdc14 in C. albicans.
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30
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Tye BW, Commins N, Ryazanova LV, Wühr M, Springer M, Pincus D, Churchman LS. Proteotoxicity from aberrant ribosome biogenesis compromises cell fitness. eLife 2019; 8:43002. [PMID: 30843788 PMCID: PMC6453566 DOI: 10.7554/elife.43002] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/06/2019] [Indexed: 12/31/2022] Open
Abstract
To achieve maximal growth, cells must manage a massive economy of ribosomal proteins (r-proteins) and RNAs (rRNAs) to produce thousands of ribosomes every minute. Although ribosomes are essential in all cells, natural disruptions to ribosome biogenesis lead to heterogeneous phenotypes. Here, we model these perturbations in Saccharomyces cerevisiae and show that challenges to ribosome biogenesis result in acute loss of proteostasis. Imbalances in the synthesis of r-proteins and rRNAs lead to the rapid aggregation of newly synthesized orphan r-proteins and compromise essential cellular processes, which cells alleviate by activating proteostasis genes. Exogenously bolstering the proteostasis network increases cellular fitness in the face of challenges to ribosome assembly, demonstrating the direct contribution of orphan r-proteins to cellular phenotypes. We propose that ribosome assembly is a key vulnerability of proteostasis maintenance in proliferating cells that may be compromised by diverse genetic, environmental, and xenobiotic perturbations that generate orphan r-proteins. Cells are made up of thousands of different proteins that perform unique roles required for life. To create all of these proteins, cells use machines called ribosomes that are partly formed of elements known as r-proteins. When cells grow and divide, the ribosomes have to make copies of themselves through a process called ribosome biogenesis. Although all cells need ribosomes, certain types of cells are especially sensitive to events that interfere with ribosome biogenesis. For example, patients that have mutations in genes needed for ribosome biogenesis produce fewer red blood cells, but their other cells and tissues are mostly healthy. It is not clear why some cells are more sensitive than others. Ribosome biogenesis is very similar between different organisms, so researchers often use budding yeast as a model to study the process. Here, Tye et al. used genetic and chemical tools to interfere with ribosome biogenesis on short time scales, which made it possible to detect early on what was going wrong in the cells. The experiments found that when ribosome biogenesis was disrupted, r-proteins that were waiting to be assembled into ribosomes quickly stuck to one another and formed clumps that reduced the ability of the yeast cells to grow. The cells responded by switching on a protein called Hsf1, which restored their ability to grow. Yeast cells that were growing quickly, and therefore making more ribosomes, were more sensitive to abnormal ribosome biogenesis than slow-growing cells. These results indicate that how actively a cell is growing, and its ability to cope with r-proteins sticking together, may in part explain why certain cells are more vulnerable to events that interfere with ribosome biogenesis. Since human cells also have Hsf1, future experiments could investigate whether turning it on might also protect fast-growing human cells from such events.
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Affiliation(s)
- Blake W Tye
- Department of Genetics, Harvard Medical School, Boston, United States.,Program in Chemical Biology, Harvard University, Cambridge, United States
| | - Nicoletta Commins
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Lillia V Ryazanova
- Department of Molecular Biology, Princeton University, Princeton, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
| | - Michael Springer
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - David Pincus
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States.,Center for Physics of Evolving Systems, University of Chicago, Chicago, United States
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31
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Nakazawa N, Arakawa O, Ebe M, Yanagida M. Casein kinase II-dependent phosphorylation of DNA topoisomerase II suppresses the effect of a catalytic topo II inhibitor, ICRF-193, in fission yeast. J Biol Chem 2019; 294:3772-3782. [PMID: 30635402 PMCID: PMC6416453 DOI: 10.1074/jbc.ra118.004955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 01/04/2019] [Indexed: 11/06/2022] Open
Abstract
DNA topoisomerase II (topo II) regulates the topological state of DNA and is necessary for DNA replication, transcription, and chromosome segregation. Topo II has essential functions in cell proliferation and therefore is a critical target of anticancer drugs. In this study, using Phos-tag SDS-PAGE analysis in fission yeast (Schizosaccharomyces pombe), we identified casein kinase II (Cka1/CKII)-dependent phosphorylation at the C-terminal residues Ser1363 and Ser1364 in topo II. We found that this phosphorylation decreases the inhibitory effect of an anticancer catalytic inhibitor of topo II, ICRF-193, on mitosis. Consistent with the constitutive activity of Cka1/CKII, Ser1363 and Ser1364 phosphorylation of topo II was stably maintained throughout the cell cycle. We demonstrate that ICRF-193-induced chromosomal mis-segregation is further exacerbated in two temperature-sensitive mutants, cka1-372 and cka1/orb5-19, of the catalytic subunit of CKII or in the topo II nonphosphorylatable alanine double mutant top2-S1363A,S1364A but not in cells of the phosphomimetic glutamate double mutant top2-S1363E,S1364E Our results suggest that Ser1363 and Ser1364 in topo II are targeted by Cka1/CKII kinase and that their phosphorylation facilitates topo II ATPase activity in the N-terminal region, which regulates protein turnover on chromosome DNA. Because CKII-mediated phosphorylation of the topo II C-terminal domain appears to be evolutionarily conserved, including in humans, we propose that attenuation of CKII-controlled topo II phosphorylation along with catalytic topo II inhibition may promote anticancer effects.
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Affiliation(s)
- Norihiko Nakazawa
- From the G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Orie Arakawa
- From the G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Masahiro Ebe
- From the G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Mitsuhiro Yanagida
- From the G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
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32
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Boutouja F, Stiehm CM, Platta HW. mTOR: A Cellular Regulator Interface in Health and Disease. Cells 2019; 8:cells8010018. [PMID: 30609721 PMCID: PMC6356367 DOI: 10.3390/cells8010018] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/25/2018] [Accepted: 01/01/2019] [Indexed: 12/19/2022] Open
Abstract
The mechanistic target of Rapamycin (mTOR) is a ubiquitously-conserved serine/threonine kinase, which has a central function in integrating growth signals and orchestrating their physiologic effects on cellular level. mTOR is the core component of differently composed signaling complexes that differ in protein composition and molecular targets. Newly identified classes of mTOR inhibitors are being developed to block autoimmune diseases and transplant rejections but also to treat obesity, diabetes, and different types of cancer. Therefore, the selective and context-dependent inhibition of mTOR activity itself might come into the focus as molecular target to prevent severe diseases and possibly to extend life span. This review provides a general introduction to the molecular composition and physiologic function of mTOR complexes as part of the Special Issue “2018 Select Papers by Cells’ Editorial Board Members”.
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Affiliation(s)
- Fahd Boutouja
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Christian M Stiehm
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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33
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RNA helicases mediate structural transitions and compositional changes in pre-ribosomal complexes. Nat Commun 2018; 9:5383. [PMID: 30568249 PMCID: PMC6300602 DOI: 10.1038/s41467-018-07783-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 11/28/2018] [Indexed: 01/31/2023] Open
Abstract
Production of eukaryotic ribosomal subunits is a highly dynamic process; pre-ribosomes undergo numerous structural rearrangements that establish the architecture present in mature complexes and serve as key checkpoints, ensuring the fidelity of ribosome assembly. Using in vivo crosslinking, we here identify the pre-ribosomal binding sites of three RNA helicases. Our data support roles for Has1 in triggering release of the U14 snoRNP, a critical event during early 40S maturation, and in driving assembly of domain I of pre-60S complexes. Binding of Mak5 to domain II of pre-60S complexes promotes recruitment of the ribosomal protein Rpl10, which is necessary for subunit joining and ribosome function. Spb4 binds to a molecular hinge at the base of ES27 facilitating binding of the export factor Arx1, thereby promoting pre-60S export competence. Our data provide important insights into the driving forces behind key structural remodelling events during ribosomal subunit assembly.
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34
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Chaker-Margot M. Assembly of the small ribosomal subunit in yeast: mechanism and regulation. RNA (NEW YORK, N.Y.) 2018; 24:881-891. [PMID: 29712726 PMCID: PMC6004059 DOI: 10.1261/rna.066985.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The eukaryotic ribosome is made of four intricately folded ribosomal RNAs and 79 proteins. During rapid growth, yeast cells produce an incredible 2000 ribosomes every minute. Ribosome assembly involves more than 200 trans-acting factors, intervening from the transcription of the preribosomal RNA in the nucleolus to late maturation events in the cytoplasm. The biogenesis of the small ribosomal subunit, or 40S, is especially intricate, requiring more than four times the mass of the small subunit in assembly factors for its full maturation. Recent studies have provided new insights into the complex assembly of the 40S subunit. These data from cryo-electron microscopy, X-ray crystallography, and other biochemical and molecular biology methods, have elucidated the role of many factors required in small subunit maturation. Mechanisms of the regulation of ribosome assembly have also emerged from this body of work. This review aims to integrate these new results into an updated view of small subunit biogenesis and its regulation, in yeast, from transcription to the formation of the mature small subunit.
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Affiliation(s)
- Malik Chaker-Margot
- The Rockefeller University, New York, New York 10065, USA
- Tri-Institutional Program in Chemical Biology, New York, New York 10065, USA
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35
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Choque E, Schneider C, Gadal O, Dez C. Turnover of aberrant pre-40S pre-ribosomal particles is initiated by a novel endonucleolytic decay pathway. Nucleic Acids Res 2018; 46:4699-4714. [PMID: 29481617 PMCID: PMC5961177 DOI: 10.1093/nar/gky116] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/29/2018] [Accepted: 02/09/2018] [Indexed: 01/05/2023] Open
Abstract
Ribosome biogenesis requires more than 200 trans-acting factors to achieve the correct production of the two mature ribosomal subunits. Here, we have identified Efg1 as a novel, nucleolar ribosome biogenesis factor in Saccharomyces cerevisiae that is directly linked to the surveillance of pre-40S particles. Depletion of Efg1 impairs early pre-rRNA processing, leading to a strong decrease in 18S rRNA and 40S subunit levels and an accumulation of the aberrant 23S rRNA. Using Efg1 as bait, we revealed a novel degradation pathway of the 23S rRNA. Co-immunoprecipitation experiments showed that Efg1 is a component of 90S pre-ribosomes, as it is associated with the 35S pre-rRNA and U3 snoRNA, but has stronger affinity for 23S pre-rRNA and its novel degradation intermediate 11S rRNA. 23S is cleaved at a new site, Q1, within the 18S sequence by the endonuclease Utp24, generating 11S and 17S' rRNA. Both of these cleavage products are targeted for degradation by the TRAMP/exosome complexes. Therefore, the Q1 site defines a novel endonucleolytic cleavage site of ribosomal RNA exclusively dedicated to surveillance of pre-ribosomal particles.
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Affiliation(s)
- Elodie Choque
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse Cedex 9, France
| | - Claudia Schneider
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Olivier Gadal
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse Cedex 9, France
| | - Christophe Dez
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse Cedex 9, France
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36
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An W, Du Y, Ye K. Structural and functional analysis of Utp24, an endonuclease for processing 18S ribosomal RNA. PLoS One 2018; 13:e0195723. [PMID: 29641590 PMCID: PMC5895043 DOI: 10.1371/journal.pone.0195723] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 03/28/2018] [Indexed: 01/05/2023] Open
Abstract
The precursor ribosomal RNA is processed by multiple steps of nucleolytic cleavage to generate mature rRNAs. Utp24 is a PIN domain endonuclease in the early 90S precursor of small ribosomal subunit and is proposed to cleave at sites A1 and A2 of pre-rRNA. Here we determine the crystal structure of Utp24 from Schizosaccharomyces pombe at 2.1 angstrom resolution. Utp24 structurally resembles the ribosome assembly factor Utp23 and both contain a Zn-finger motif. Functional analysis in Saccharomyces cerevisiae shows that depletion of Utp24 disturbs the assembly of 90S and abolishes cleavage at sites A0, A1 and A2. The 90S assembled with inactivated Utp24 is arrested at a post-A0-cleavage state and contains enriched nuclear exosome for degradation of 5' ETS. Despite of high sequence conservation, Utp24 from other organisms is unable to form an active 90S in S. cerevisiae, suggesting that Utp24 needs to be precisely positioned in 90S. Our study provides biochemical and structural insight into the role of Utp24 in 90S assembly and activity.
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Affiliation(s)
- Weidong An
- College of Biological Sciences, China Agricultural University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yifei Du
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Keqiong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- * E-mail:
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37
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Sanghai ZA, Miller L, Molloy KR, Barandun J, Hunziker M, Chaker-Margot M, Wang J, Chait BT, Klinge S. Modular assembly of the nucleolar pre-60S ribosomal subunit. Nature 2018; 556:126-129. [PMID: 29512650 DOI: 10.1038/nature26156] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/23/2018] [Indexed: 12/13/2022]
Abstract
Early co-transcriptional events during eukaryotic ribosome assembly result in the formation of precursors of the small (40S) and large (60S) ribosomal subunits. A multitude of transient assembly factors regulate and chaperone the systematic folding of pre-ribosomal RNA subdomains. However, owing to a lack of structural information, the role of these factors during early nucleolar 60S assembly is not fully understood. Here we report cryo-electron microscopy (cryo-EM) reconstructions of the nucleolar pre-60S ribosomal subunit in different conformational states at resolutions of up to 3.4 Å. These reconstructions reveal how steric hindrance and molecular mimicry are used to prevent both premature folding states and binding of later factors. This is accomplished by the concerted activity of 21 ribosome assembly factors that stabilize and remodel pre-ribosomal RNA and ribosomal proteins. Among these factors, three Brix-domain proteins and their binding partners form a ring-like structure at ribosomal RNA (rRNA) domain boundaries to support the architecture of the maturing particle. The existence of mutually exclusive conformations of these pre-60S particles suggests that the formation of the polypeptide exit tunnel is achieved through different folding pathways during subsequent stages of ribosome assembly. These structures rationalize previous genetic and biochemical data and highlight the mechanisms that drive eukaryotic ribosome assembly in a unidirectional manner.
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Affiliation(s)
- Zahra Assur Sanghai
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Linamarie Miller
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.,Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York 10065, USA
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Jonas Barandun
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Mirjam Hunziker
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Malik Chaker-Margot
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.,Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York 10065, USA
| | - Junjie Wang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
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38
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Assembly and structure of the SSU processome-a nucleolar precursor of the small ribosomal subunit. Curr Opin Struct Biol 2018; 49:85-93. [PMID: 29414516 DOI: 10.1016/j.sbi.2018.01.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 12/22/2022]
Abstract
The small subunit processome is the first precursor of the small eukaryotic ribosomal subunit. During its assembly in the nucleolus, many ribosome biogenesis factors, an RNA chaperone, and ribosomal proteins associate with the nascent pre-rRNA. Biochemical studies have elucidated the rRNA-subdomain dependent recruitment of these factors during SSU processome assembly and have been complemented by structural studies of the assembled particle. Ribosome biogenesis factors encapsulate and guide subdomains of pre-ribosomal RNA in distinct compartments. This prevents uncoordinated maturation and enables processing of regions not accessible in the mature subunit. By sequentially reducing conformational freedom, flexible proteins facilitate the incorporation of dynamic subcomplexes into a globular particle. Large rearrangements within the SSU processome are required for compaction into the mature small ribosomal subunit.
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39
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Prasinovirus Attack of Ostreococcus Is Furtive by Day but Savage by Night. J Virol 2018; 92:JVI.01703-17. [PMID: 29187539 PMCID: PMC5790953 DOI: 10.1128/jvi.01703-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/09/2017] [Indexed: 12/12/2022] Open
Abstract
Prasinoviruses are large DNA viruses that infect diverse genera of green microalgae worldwide in aquatic ecosystems, but molecular knowledge of their life cycles is lacking. Several complete genomes of both these viruses and their marine algal hosts are now available and have been used to show the pervasive presence of these species in microbial metagenomes. We have analyzed the life cycle of Ostreococcus tauri virus 5 (OtV5), a lytic virus, using transcriptome sequencing (RNA-Seq) from 12 time points of healthy or infected Ostreococcus tauri cells over a day/night cycle in culture. In the day, viral gene transcription remained low while host nitrogen metabolism gene transcription was initially strongly repressed for two successive time points before being induced for 8 h, but during the night, viral transcription increased steeply while host nitrogen metabolism genes were repressed and many host functions that are normally reduced in the dark appeared to be compensated either by genes expressed from the virus or by increased expression of a subset of 4.4% of the host's genes. Some host cells underwent lysis progressively during the night, but a larger proportion were lysed the following morning. Our data suggest that the life cycles of algal viruses mirror the diurnal rhythms of their hosts.IMPORTANCE Prasinoviruses are common in marine environments, and although several complete genomes of these viruses and their hosts have been characterized, little is known about their life cycles. Here we analyze in detail the transcriptional changes occurring over a 27-h-long experiment in a natural diurnal rhythm, in which the growth of host cells is to some extent synchronized, so that host DNA replication occurs late in the day or early in the night and cell division occurs during the night. Surprisingly, viral transcription remains quiescent over the daytime, when the most energy (from light) is available, but during the night viral transcription activates, accompanied by expression of a few host genes that are probably required by the virus. Although our experiment was accomplished in the lab, cyclical changes have been documented in host transcription in the ocean. Our observations may thus be relevant for eukaryotic phytoplankton in natural environments.
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40
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Matos-Perdomo E, Machín F. The ribosomal DNA metaphase loop of Saccharomyces cerevisiae gets condensed upon heat stress in a Cdc14-independent TORC1-dependent manner. Cell Cycle 2018; 17:200-215. [PMID: 29166821 PMCID: PMC5884360 DOI: 10.1080/15384101.2017.1407890] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Chromosome morphology in Saccharomyces cerevisiae is only visible at the microscopic level in the ribosomal DNA array (rDNA). The rDNA has been thus used as a model to characterize condensation and segregation of sister chromatids in mitosis. It has been established that the metaphase structure ("loop") depends, among others, on the condensin complex; whereas its segregation also depends on that complex, the Polo-like kinase Cdc5 and the cell cycle master phosphatase Cdc14. In addition, Cdc14 also drives rDNA hypercondensation in telophase. Remarkably, since all these components are essential for cell survival, their role on rDNA condensation and segregation was established by temperature-sensitive (ts) alleles. Here, we show that the heat stress (HS) used to inactivate ts alleles (25 ºC to 37 ºC shift) causes rDNA loop condensation in metaphase-arrested wild type cells, a result that can also be mimicked by other stresses that inhibit the TORC1 pathway. Because this condensation might challenge previous findings with ts alleles, we have repeated classical experiments of rDNA condensation and segregation, yet using instead auxin-driven degradation alleles (aid alleles). We have undertaken the protein degradation at lower temperatures (25 ºC) and concluded that the classical roles for condensin, Cdc5, Cdc14 and Cdc15 still prevailed. Thus, condensin degradation disrupts rDNA higher organization, Cdc14 and Cdc5 degradation precludes rDNA segregation and Cdc15 degradation still allows rDNA hypercompaction in telophase. Finally, we provide direct genetic evidence that this HS-mediated rDNA condensation is dependent on TORC1 but, unlike the one observed in anaphase, is independent of Cdc14.
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Affiliation(s)
- Emiliano Matos-Perdomo
- a Unidad de Investigación , Hospital Universitario Ntra Sra de Candelaria , Ctra del Rosario 145, 38010 , Santa Cruz de Tenerife , Spain.,b Universidad de La Laguna , Tenerife , Spain
| | - Félix Machín
- a Unidad de Investigación , Hospital Universitario Ntra Sra de Candelaria , Ctra del Rosario 145, 38010 , Santa Cruz de Tenerife , Spain
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41
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Shedlovskiy D, Shcherbik N, Pestov DG. One-step hot formamide extraction of RNA from Saccharomyces cerevisiae. RNA Biol 2017; 14:1722-1726. [PMID: 28692404 PMCID: PMC5731811 DOI: 10.1080/15476286.2017.1345417] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/11/2017] [Accepted: 06/19/2017] [Indexed: 11/07/2022] Open
Abstract
Current methods for isolating RNA from budding yeast require lengthy and laborious steps such as freezing and heating with phenol, homogenization with glass beads, or enzymatic digestion of the cell wall. Here, extraction with a solution of formamide and EDTA was adapted to isolate RNA from whole yeast cells through a rapid and easily scalable procedure that does not require mechanical cell lysis, phenol, or enzymes. RNA extracted with formamide-EDTA can be directly loaded on gels for electrophoretic analysis without alcohol precipitation. A simplified protocol for downstream DNase treatment and reverse transcription reaction is also included. The formamide-EDTA extraction of yeast RNA is faster, safer, and more economical than conventional methods, outperforms them in terms of total yield, and greatly increases throughput.
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Affiliation(s)
- Daniel Shedlovskiy
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
| | - Natalia Shcherbik
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
| | - Dimitri G. Pestov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, USA
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42
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Rusin SF, Adamo ME, Kettenbach AN. Identification of Candidate Casein Kinase 2 Substrates in Mitosis by Quantitative Phosphoproteomics. Front Cell Dev Biol 2017; 5:97. [PMID: 29214152 PMCID: PMC5702644 DOI: 10.3389/fcell.2017.00097] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/30/2022] Open
Abstract
Protein phosphorylation is a crucial regulatory mechanism that controls many aspects of cellular signaling. Casein kinase 2 (CK2), a constitutively expressed and active kinase, plays key roles in an array of cellular events including transcription and translation, ribosome biogenesis, cell cycle progression, and apoptosis. CK2 is implicated in cancerous transformation and is a therapeutic target in anti-cancer therapy. The specific and selective CK2 ATP competitive inhibitor, CX-4945 (silmitaseratib), is currently in phase 2 clinical trials. While many substrates and interactors of CK2 have been identified, less is known about CK2 substrates in mitosis. In the present work, we utilize CX-4945 and quantitative phosphoproteomics to inhibit CK2 activity in mitotically arrested HeLa cells and determine candidate CK2 substrates. We identify 330 phosphorylation sites on 202 proteins as significantly decreased in abundance upon inhibition of CK2 activity. Motif analysis of decreased sites reveals a linear kinase motif with aspartic and glutamic amino acids downstream of the phosphorylated residues, which is consistent with known substrate preferences for CK2. To validate specific candidate CK2 substrates, we perform in vitro kinase assays using purified components. Furthermore, we identified CK2 interacting proteins by affinity purification-mass spectrometry (AP-MS). To investigate the biological processes regulated by CK2 in mitosis, we perform network analysis and identify an enrichment of proteins involved in chromosome condensation, chromatin organization, and RNA processing. We demonstrate that overexpression of CK2 in HeLa cells affects proper chromosome condensation. Previously, we found that phosphoprotein phosphatase 6 (PP6), but not phosphoprotein phosphatase 2A (PP2A), opposes CK2 phosphorylation of the condensin I complex, which is essential for chromosome condensation. Here, we extend this observation and demonstrate that PP6 opposition of CK2 is a more general cellular regulatory mechanism.
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Affiliation(s)
- Scott F Rusin
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Mark E Adamo
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
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43
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Barandun J, Chaker-Margot M, Hunziker M, Molloy KR, Chait BT, Klinge S. The complete structure of the small-subunit processome. Nat Struct Mol Biol 2017; 24:944-953. [PMID: 28945246 DOI: 10.1038/nsmb.3472] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/25/2017] [Indexed: 01/24/2023]
Abstract
The small-subunit processome represents the earliest stable precursor of the eukaryotic small ribosomal subunit. Here we present the cryo-EM structure of the Saccharomyces cerevisiae small-subunit processome at an overall resolution of 3.8 Å, which provides an essentially complete near-atomic model of this assembly. In this nucleolar superstructure, 51 ribosome-assembly factors and two RNAs encapsulate the 18S rRNA precursor and 15 ribosomal proteins in a state that precedes pre-rRNA cleavage at site A1. Extended flexible proteins are employed to connect distant sites in this particle. Molecular mimicry and steric hindrance, as well as protein- and RNA-mediated RNA remodeling, are used in a concerted fashion to prevent the premature formation of the central pseudoknot and its surrounding elements within the small ribosomal subunit.
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Affiliation(s)
- Jonas Barandun
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
| | - Malik Chaker-Margot
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
- Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York, USA
| | - Mirjam Hunziker
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
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44
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de la Cruz J, Gómez-Herreros F, Rodríguez-Galán O, Begley V, de la Cruz Muñoz-Centeno M, Chávez S. Feedback regulation of ribosome assembly. Curr Genet 2017; 64:393-404. [PMID: 29022131 DOI: 10.1007/s00294-017-0764-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 10/06/2017] [Accepted: 10/07/2017] [Indexed: 12/12/2022]
Abstract
Ribosome biogenesis is a crucial process for growth and constitutes the major consumer of cellular resources. This pathway is subjected to very stringent regulation to ensure correct ribosome manufacture with a wide variety of environmental and metabolic changes, and intracellular insults. Here we summarise our current knowledge on the regulation of ribosome biogenesis in Saccharomyces cerevisiae by particularly focusing on the feedback mechanisms that maintain ribosome homeostasis. Ribosome biogenesis in yeast is controlled mainly at the level of the production of both pre-rRNAs and ribosomal proteins through the transcriptional and post-transcriptional control of the TORC1 and protein kinase A signalling pathways. Pre-rRNA processing can occur before or after the 35S pre-rRNA transcript is completed; the switch between these two alternatives is regulated by growth conditions. The expression of both ribosomal proteins and the large family of transacting factors involved in ribosome biogenesis is co-regulated. Recently, it has been shown that the synthesis of rRNA and ribosomal proteins, but not of trans-factors, is coupled. Thus the so-called CURI complex sequesters specific transcription factor Ifh1 to repress ribosomal protein genes when rRNA transcription is impaired. We recently found that an analogue system should operate to control the expression of transacting factor genes in response to actual ribosome assembly performance. Regulation of ribosome biogenesis manages situations of imbalanced ribosome production or misassembled ribosomal precursors and subunits, which have been closely linked to distinct human diseases.
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Affiliation(s)
- Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain. .,Departamento de Genética, Universidad de Sevilla, Seville, Spain.
| | - Fernando Gómez-Herreros
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Victoria Begley
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - María de la Cruz Muñoz-Centeno
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain.,Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Sebastián Chávez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC, Universidad de Sevilla, Seville, Spain. .,Departamento de Genética, Universidad de Sevilla, Seville, Spain.
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45
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Eukaryotic ribosome assembly, transport and quality control. Nat Struct Mol Biol 2017; 24:689-699. [PMID: 28880863 DOI: 10.1038/nsmb.3454] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/27/2017] [Indexed: 12/18/2022]
Abstract
Eukaryotic ribosome synthesis is a complex, energy-consuming process that takes place across the nucleolus, nucleoplasm and cytoplasm and requires more than 200 conserved assembly factors. Here, we discuss mechanisms by which the ribosome assembly and nucleocytoplasmic transport machineries collaborate to produce functional ribosomes. We also highlight recent cryo-EM studies that provided unprecedented snapshots of ribosomes during assembly and quality control.
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Tomecki R, Sikorski PJ, Zakrzewska-Placzek M. Comparison of preribosomal RNA processing pathways in yeast, plant and human cells - focus on coordinated action of endo- and exoribonucleases. FEBS Lett 2017; 591:1801-1850. [PMID: 28524231 DOI: 10.1002/1873-3468.12682] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Abstract
Proper regulation of ribosome biosynthesis is mandatory for cellular adaptation, growth and proliferation. Ribosome biogenesis is the most energetically demanding cellular process, which requires tight control. Abnormalities in ribosome production have severe consequences, including developmental defects in plants and genetic diseases (ribosomopathies) in humans. One of the processes occurring during eukaryotic ribosome biogenesis is processing of the ribosomal RNA precursor molecule (pre-rRNA), synthesized by RNA polymerase I, into mature rRNAs. It must not only be accurate but must also be precisely coordinated with other phenomena leading to the synthesis of functional ribosomes: RNA modification, RNA folding, assembly with ribosomal proteins and nucleocytoplasmic RNP export. A multitude of ribosome biogenesis factors ensure that these events take place in a correct temporal order. Among them are endo- and exoribonucleases involved in pre-rRNA processing. Here, we thoroughly present a wide spectrum of ribonucleases participating in rRNA maturation, focusing on their biochemical properties, regulatory mechanisms and substrate specificity. We also discuss cooperation between various ribonucleolytic activities in particular stages of pre-rRNA processing, delineating major similarities and differences between three representative groups of eukaryotes: yeast, plants and humans.
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Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Poland
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47
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Merret R, Carpentier MC, Favory JJ, Picart C, Descombin J, Bousquet-Antonelli C, Tillard P, Lejay L, Deragon JM, Charng YY. Heat Shock Protein HSP101 Affects the Release of Ribosomal Protein mRNAs for Recovery after Heat Shock. PLANT PHYSIOLOGY 2017; 174:1216-1225. [PMID: 28381501 PMCID: PMC5462041 DOI: 10.1104/pp.17.00269] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/03/2017] [Indexed: 05/21/2023]
Abstract
Heat shock (HS) is known to have a profound impact on gene expression at different levels, such as inhibition of protein synthesis, in which HS blocks translation initiation and induces the sequestration of mRNAs into stress granules (SGs) or P-bodies for storage and/or decay. SGs prevent the degradation of the stored mRNAs, which can be reengaged into translation in the recovery period. However, little is known on the mRNAs stored during the stress, how these mRNAs are released from SGs afterward, and what the functional importance is of this process. In this work, we report that Arabidopsis HEAT SHOCK PROTEIN101 (HSP101) knockout mutant (hsp101) presented a defect in translation recovery and SG dissociation after HS Using RNA sequencing and RNA immunoprecipitation approaches, we show that mRNAs encoding ribosomal proteins (RPs) were preferentially stored during HS and that these mRNAs were released and translated in an HSP101-dependent manner during recovery. By 15N incorporation and polysome profile analyses, we observed that these released mRNAs contributed to the production of new ribosomes to enhance translation. We propose that, after HS, HSP101 is required for the efficient release of RP mRNAs from SGs resulting in a rapid restoration of the translation machinery by producing new RPs.
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Affiliation(s)
- Rémy Merret
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.);
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.);
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.);
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Marie-Christine Carpentier
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Jean-Jacques Favory
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Claire Picart
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Julie Descombin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Cécile Bousquet-Antonelli
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Pascal Tillard
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Laurence Lejay
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Jean-Marc Deragon
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.)
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.)
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
| | - Yee-Yung Charng
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529, Republic of China (R.M., Y.-y.C.);
- CNRS-LGDP UMR 5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.);
- Université de Perpignan Via Domitia, LGDP-UMR5096, 66860 Perpignan, France (R.M., M.-C.C., J.-J.F., C.P., J.D., C.B.-A., J.-M.D.);
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon,' UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier cedex, France (P.T., L.L.); and
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris cedex 05, France (J.-M.D.)
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