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Deryabin A, Moraleva A, Dobrochaeva K, Kovaleva D, Rubtsova M, Dontsova O, Rubtsov Y. Human RPF1 and ESF1 in Pre-rRNA Processing and the Assembly of Pre-Ribosomal Particles: A Functional Study. Cells 2024; 13:326. [PMID: 38391939 PMCID: PMC10886481 DOI: 10.3390/cells13040326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
Ribosome biogenesis is essential for the functioning of living cells. In higher eukaryotes, this multistep process is tightly controlled and involves a variety of specialized proteins and RNAs. This pool of so-called ribosome biogenesis factors includes diverse proteins with enzymatic and structural functions. Some of them have homologs in yeast S. cerevisiae, and their function can be inferred from the structural and biochemical data obtained for the yeast counterparts. The functions of human proteins RPF1 and ESF1 remain largely unclear, although RPF1 has been recently shown to participate in 60S biogenesis. Both proteins have drawn our attention since they contribute to the early stages of ribosome biogenesis, which are far less studied than the later stages. In this study, we employed the loss-of-function shRNA/siRNA-based approach to the human cell line HEK293 to determine the role of RPF1 and ESF1 in ribosome biogenesis. Downregulating RPF1 and ESF1 significantly changed the pattern of RNA products derived from 47S pre-rRNA. Our findings demonstrate that RPF1 and ESF1 are associated with different pre-ribosomal particles, pre-60S, and pre-40S particles, respectively. Our results allow for speculation about the particular steps of pre-rRNA processing, which highly rely on the RPF1 and ESF1 functions. We suggest that both factors are not directly involved in pre-rRNA cleavage but rather help pre-rRNA to acquire the conformation favoring its cleavage.
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Affiliation(s)
- Alexander Deryabin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
| | - Anastasiia Moraleva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
- Department of Applied Mathematics, MIREA-Russian Technological University, 119454 Moscow, Russia
| | - Kira Dobrochaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
| | - Diana Kovaleva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
| | - Maria Rubtsova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga Dontsova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Yury Rubtsov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 119997 Moscow, Russia
- N.N.Blokhin National Medical Research Center of Oncology, Ministry of Health of the Russian Federation, 115478 Moscow, Russia
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Yu Q, Walters HE, Pasquini G, Pal Singh S, Lachnit M, Oliveira CR, León-Periñán D, Petzold A, Kesavan P, Subiran Adrados C, Garteizgogeascoa I, Knapp D, Wagner A, Bernardos A, Alfonso M, Nadar G, Graf AM, Troyanovskiy KE, Dahl A, Busskamp V, Martínez-Máñez R, Yun MH. Cellular senescence promotes progenitor cell expansion during axolotl limb regeneration. Dev Cell 2023; 58:2416-2427.e7. [PMID: 37879337 DOI: 10.1016/j.devcel.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 04/25/2023] [Accepted: 09/29/2023] [Indexed: 10/27/2023]
Abstract
Axolotl limb regeneration is accompanied by the transient induction of cellular senescence within the blastema, the structure that nucleates regeneration. The precise role of this blastemal senescent cell (bSC) population, however, remains unknown. Here, through a combination of gain- and loss-of-function assays, we elucidate the functions and molecular features of cellular senescence in vivo. We demonstrate that cellular senescence plays a positive role during axolotl regeneration by creating a pro-proliferative niche that supports progenitor cell expansion and blastema outgrowth. Senescent cells impact their microenvironment via Wnt pathway modulation. Further, we identify a link between Wnt signaling and senescence induction and propose that bSC-derived Wnt signals facilitate the proliferation of neighboring cells in part by preventing their induction into senescence. This work defines the roles of cellular senescence in the regeneration of complex structures.
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Affiliation(s)
- Qinghao Yu
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Hannah E Walters
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Giovanni Pasquini
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | | | - Martina Lachnit
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Catarina R Oliveira
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Daniel León-Periñán
- Technische Universität Dresden, Center for Information Services and High Performance Computing (ZIH), Technische Universität Dresden, Dresden, Germany
| | - Andreas Petzold
- DRESDEN-Concept Genome Center (DcGC), Center for Molecular and Cellular Bioengineering, TU Dresden, Dresden, Germany
| | - Preethi Kesavan
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Cristina Subiran Adrados
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | | | - Dunja Knapp
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Anne Wagner
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | - Andrea Bernardos
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Valencia, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Madrid, Spain; Unidad Mixta UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina, Universitat Politècnica de València, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - María Alfonso
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Valencia, Spain
| | - Gayathri Nadar
- Max Planck Institute of Molecular Cellular Biology and Genetics, Dresden, Germany
| | - Alwin M Graf
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany
| | | | - Andreas Dahl
- DRESDEN-Concept Genome Center (DcGC), Center for Molecular and Cellular Bioengineering, TU Dresden, Dresden, Germany
| | - Volker Busskamp
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Ramón Martínez-Máñez
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Valencia, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Madrid, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores, Universitat Politècnica de València, IIS La Fe, Valencia, Spain; Unidad Mixta UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina, Universitat Politècnica de València, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Maximina H Yun
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, Dresden, Germany; Max Planck Institute of Molecular Cellular Biology and Genetics, Dresden, Germany; Physics of Life Excellence Cluster, Dresden, Germany.
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3
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Alidou-D'Anjou I, Patel A, Sleiman S, Dragon F. Human SHQ1 variants R335C and A426V lead to severe ribosome biogenesis defects when expressed in yeast. Front Genet 2023; 14:1240416. [PMID: 37818102 PMCID: PMC10560722 DOI: 10.3389/fgene.2023.1240416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 08/17/2023] [Indexed: 10/12/2023] Open
Abstract
SHQ1 is an essential chaperone that binds the pseudouridine synthase dyskerin in the cytoplasm and escorts the enzyme to the nucleus, where dyskerin is assembled into small nucleolar RNPs (snoRNPs) of the H/ACA class. These particles carry out pseudouridine formation in ribosomal RNAs (rRNAs) and participate in maturation of rRNA precursors (pre-rRNAs). Variants of human SHQ1 have been linked to neurodevelopmental deficiencies; here we focused on two compound heterozygous mutations identified in a child showing a severe neurological disorder comprising cerebellar degeneration. To investigate the molecular defects caused by mutations R335C and A426V we used a conditional yeast strain that can be depleted of the endogenous Shq1 protein while constitutively expressing human SHQ1 (wild-type or variants). Although wild-type SHQ1 complemented the Shq1-depleted strain, cells expressing variant R335C could not support growth, and cells expressing variant A426V were temperature-sensitive. When shifted to restrictive conditions, yeast cells progressively lost H/ACA snoRNAs and accumulated unprocessed pre-rRNAs, which led to reduced production of ribosomes. Levels of Cbf5 (yeast homologue of dyskerin) were decreased in yeast cells expressing SHQ1 variants under restrictive conditions. Immunoprecipitation experiments revealed that interaction of Cbf5 with SHQ1 variants was weakened but not abolished, and yeast two-hybrid assays showed that mutation R335C is more deleterious than mutation A426V. Our data provide additional evidence for the critical role of SHQ1 in chaperoning the pseudouridine synthase dyskerin, and how its inadequate function has detrimental consequences on the production of H/ACA snoRNPs and ribosomes.
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Affiliation(s)
- Ismaël Alidou-D'Anjou
- Centre d'Excellence en Recherche sur les Maladies Orphelines-Fondation Courtois (CERMO-FC), Départment des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Aniket Patel
- Centre d'Excellence en Recherche sur les Maladies Orphelines-Fondation Courtois (CERMO-FC), Départment des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Sophie Sleiman
- Centre d'Excellence en Recherche sur les Maladies Orphelines-Fondation Courtois (CERMO-FC), Départment des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - François Dragon
- Centre d'Excellence en Recherche sur les Maladies Orphelines-Fondation Courtois (CERMO-FC), Départment des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
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Ho DH, Kim H, Nam D, Heo J, Son I. Nuclear α-Synuclein-Derived Cytotoxic Effect via Altered Ribosomal RNA Processing in Primary Mouse Embryonic Fibroblasts. Int J Mol Sci 2023; 24. [PMID: 36768455 DOI: 10.3390/ijms24032132] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
α-Synuclein (αSyn) is an important player in Parkinson's disease (PD) pathogenesis. The aggregation of αSyn is mainly formed in the cytoplasm, whereas some αSyn accumulation has also been found in the nuclei of neurons. To assess the effect of nuclear αSyn, we generated αSyn conjugated with a nuclear export signal (NES) or a nuclear localization signal (NLS), and compared them with wild-type αSyn in primary mouse embryonic fibroblasts (MEF) using DNA transfection. Overexpression of NLS-αSyn increased cytotoxicity. The levels of apoptotic markers were increased by NLS-αSyn in MEF. Interestingly, an increase in the levels of 40S ribosomal protein 15 was observed in MEF expressing NLS-αSyn. These MEF also showed a higher 28S/18S rRNA ratio. Intriguingly, the expression of NLS-αSyn in MEF enhanced segmentation of nucleolin (NCL)-positive nucleolar structures. We also observed that the downregulation of NCL, using shRNA, promoted a relatively higher 28S/18S rRNA ratio. The reduction in NCL expression accelerated the accumulation of αSyn, and NCL transfection enhanced the degradation of αSyn. These results suggest that nuclear αSyn contributes to the alteration in ribosomal RNA processing via NCL malfunction-mediated nucleolar segmentation, and that NCL is a key factor for the degradation of αSyn.
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Abstract
The ribonucleoprotein RNase MRP is responsible for the processing of ribosomal RNA precursors. It is found in virtually all eukaryotes that have been examined. In the Euglenozoa, including the genera Euglena, Diplonema and kinetoplastids, MRP RNA and protein subunits have so far escaped detection using bioinformatic methods. However, we now demonstrate that the RNA component is widespread among the Euglenozoa and that these RNAs have secondary structures that conform to the structure of all other phylogenetic groups. In Euglena, we identified the same set of P/MRP protein subunits as in many other protists. However, we failed to identify any of these proteins in the kinetoplastids. This finding poses interesting questions regarding the structure and function of RNase MRP in these species.
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Affiliation(s)
- Magnus Alm Rosenblad
- Department of Chemistry and Molecular Biology, National Infrastructure of Bioinformatics (NBIS), Lundberg Laboratory, University of Gothenburg, Gothenburg, Sweden
| | - Marcela Dávila López
- Bioinformatics Core Facility, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Tore Samuelsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
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Li M, Ruwe H, Melzer M, Junker A, Hensel G, Tschiersch H, Schwenkert S, Chamas S, Schmitz-Linneweber C, Börner T, Stein N. The Arabidopsis AAC Proteins CIL and CIA2 Are Sub-functionalized Paralogs Involved in Chloroplast Development. Front Plant Sci 2021; 12:681375. [PMID: 34163512 PMCID: PMC8215611 DOI: 10.3389/fpls.2021.681375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/06/2021] [Indexed: 05/22/2023]
Abstract
The Arabidopsis gene Chloroplast Import Apparatus 2 (CIA2) encodes a transcription factor that positively affects the activity of nuclear genes for chloroplast ribosomal proteins and chloroplast protein import machineries. CIA2-like (CIL) is the paralogous gene of CIA2. We generated a cil mutant by site-directed mutagenesis and compared it with cia2 and cia2cil double mutant. Phenotype of the cil mutant did not differ from the wild type under our growth conditions, except faster growth and earlier time to flowering. Compared to cia2, the cia2cil mutant showed more impaired chloroplast functions and reduced amounts of plastid ribosomal RNAs. In silico analyses predict for CIA2 and CIL a C-terminal CCT domain and an N-terminal chloroplast transit peptide (cTP). Chloroplast (and potentially nuclear) localization was previously shown for HvCMF3 and HvCMF7, the homologs of CIA2 and CIL in barley. We observed nuclear localization of CIL after transient expression in Arabidopsis protoplasts. Surprisingly, transformation of cia2 with HvCMF3, HvCMF7, or with a truncated CIA2 lacking the predicted cTP could partially rescue the pale-green phenotype of cia2. These data are discussed with respect to potentially overlapping functions between CIA2, CIL, and their barley homologs and to the function of the putative cTPs of CIA2 and CIL.
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Affiliation(s)
- Mingjiu Li
- Genomics of Genetic Resources, Department of Genebank, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Hannes Ruwe
- Molecular Genetics, Institute of Biology, Humboldt University, Rhoda Erdmann Haus, Berlin, Germany
| | - Michael Melzer
- Structural Cell Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | - Astrid Junker
- Acclimation Dynamics and Phenotyping, Department of Molecular Genetics, IPK, Gatersleben, Germany
| | - Goetz Hensel
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | - Henning Tschiersch
- Acclimation Dynamics and Phenotyping, Department of Molecular Genetics, IPK, Gatersleben, Germany
| | - Serena Schwenkert
- Department of Biology I, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Sindy Chamas
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | | | - Thomas Börner
- Molecular Genetics, Institute of Biology, Humboldt University, Rhoda Erdmann Haus, Berlin, Germany
| | - Nils Stein
- Genomics of Genetic Resources, Department of Genebank, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- Department of Crop Sciences, Center for Integrated Breeding Research (CiBreed), Georg-August-Universität Göttingen, Göttingen, Germany
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7
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Birkedal U, Beckert B, Wilson DN, Nielsen H. The 23S Ribosomal RNA From Pyrococcus furiosus Is Circularly Permuted. Front Microbiol 2020; 11:582022. [PMID: 33362734 PMCID: PMC7758197 DOI: 10.3389/fmicb.2020.582022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/16/2020] [Indexed: 12/29/2022] Open
Abstract
Synthesis and assembly of ribosomal components are fundamental cellular processes and generally well-conserved within the main groups of organisms. Yet, provocative variations to the general schemes exist. We have discovered an unusual processing pathway of pre-rRNA in extreme thermophilic archaea exemplified by Pyrococcus furiosus. The large subunit (LSU) rRNA is produced as a circularly permuted form through circularization followed by excision of Helix 98. As a consequence, the terminal domain VII that comprise the binding site for the signal recognition particle is appended to the 5´ end of the LSU rRNA that instead terminates in Domain VI carrying the Sarcin-Ricin Loop, the primary interaction site with the translational GTPases. To our knowledge, this is the first example of a true post-transcriptional circular permutation of a main functional molecule and the first example of rRNA fragmentation in archaea.
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Affiliation(s)
- Ulf Birkedal
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Bertrand Beckert
- Institut für Biochemie und Molekularbiologie, Universität Hamburg, Hamburg, Germany
| | - Daniel N Wilson
- Institut für Biochemie und Molekularbiologie, Universität Hamburg, Hamburg, Germany
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.,Genomics Group, Nord University, Bodø, Norway
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Gillespie A, Gabunilas J, Jen JC, Chanfreau GF. Mutations of EXOSC3/Rrp40p associated with neurological diseases impact ribosomal RNA processing functions of the exosome in S. cerevisiae. RNA 2017; 23:466-472. [PMID: 28053271 PMCID: PMC5340910 DOI: 10.1261/rna.060004.116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/22/2016] [Indexed: 05/29/2023]
Abstract
The RNA exosome is a conserved multiprotein complex that achieves a large number of processive and degradative functions in eukaryotic cells. Recently, mutations have been mapped to the gene encoding one of the subunits of the exosome, EXOSC3 (yeast Rrp40p), which results in pontocerebellar hypoplasia with motor neuron degeneration in human patients. However, the molecular impact of these mutations in the pathology of these diseases is not well understood. To investigate the molecular consequences of mutations in EXOSC3 that lead to neurological diseases, we analyzed the effect of three of the mutations that affect conserved residues of EXOSC3/Rrp40p (G31A, G191C, and W238R; G8A, G148C, and W195R, respectively, in human and yeast) in S. cerevisiae We show that the severity of the phenotypes of these mutations in yeast correlate with that of the disease in human patients, with the W195R mutant showing the strongest growth and RNA processing phenotypes. Furthermore, we show that these mutations affect more severely pre-ribosomal RNA processing functions of the exosome rather than other nuclear processing or surveillance functions. These results suggest that delayed or defective pre-rRNA processing might be the primary defect responsible for the pathologies detected in patients with mutations affecting EXOSC3 function in residues conserved throughout eukaryotes.
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Affiliation(s)
- Abby Gillespie
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California 90095-1569, USA
| | - Jason Gabunilas
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California 90095-1569, USA
| | - Joanna C Jen
- Department of Neurology, University of California, Los Angeles, California 90095-1763, USA
- Department of Neurobiology, University of California, Los Angeles, California 90095-1763, USA
| | - Guillaume F Chanfreau
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California 90095-1569, USA
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Jeon Y, Ahn CS, Jung HJ, Kang H, Park GT, Choi Y, Hwang J, Pai HS. DER containing two consecutive GTP-binding domains plays an essential role in chloroplast ribosomal RNA processing and ribosome biogenesis in higher plants. J Exp Bot 2014; 65:117-30. [PMID: 24272962 PMCID: PMC3883289 DOI: 10.1093/jxb/ert360] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This study investigated protein characteristics and physiological functions of DER (Double Era-like GTPase) of higher plants. Nicotiana benthamiana DER (NbDER) contained two tandemly repeated GTP-binding domains (GD) and a C-terminal domain (CTD) that was similar to the K-homology domain involved in RNA binding. Both GDs possessed GTPase activity and contributed to the maximum GTPase activity of NbDER. NbDER fused to green fluorescent protein was localized primarily to chloroplast nucleoids. Arabidopsis der null mutants exhibited an embryonic lethal phenotype, indicating an essential function of DER during plant embryogenesis. Virus-induced gene silencing of NbDER resulted in a leaf-yellowing phenotype caused by disrupted chloroplast biogenesis. NbDER was associated primarily with the chloroplast 50S ribosomal subunit in vivo, and both the CTD and the two GD contributed to the association. Recombinant proteins of NbDER and its CTD could bind to 23S and 16S ribosomal RNAs in vitro. Depletion of NbDER impaired processing of plastid-encoded ribosomal RNAs, resulting in accumulation of the precursor rRNAs in the chloroplasts. NbDER-deficient chloroplasts contained significantly reduced levels of mature 23S and 16S rRNAs and diverse mRNAs in the polysomal fractions, suggesting decreased translation in chloroplasts. These results suggest that DER is involved in chloroplast rRNA processing and ribosome biogenesis in higher plants.
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Affiliation(s)
- Young Jeon
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
| | - Chang Sook Ahn
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
| | - Hyun Ju Jung
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea
| | - Hunseung Kang
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea
| | - Guen Tae Park
- School of Biological Sciences, Seoul National University, Seoul 151-;747, Korea
| | - Yeonhee Choi
- School of Biological Sciences, Seoul National University, Seoul 151-;747, Korea
| | - Jihwan Hwang
- Department of Microbiology, Pusan National University, Busan 609-735, Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
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