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Ruan J, Yu X, Xu H, Cui W, Zhang K, Liu C, Sun W, Huang X, An L, Zhang Y. Suppressor tRNA in gene therapy. SCIENCE CHINA. LIFE SCIENCES 2024:10.1007/s11427-024-2613-y. [PMID: 38926247 DOI: 10.1007/s11427-024-2613-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/08/2024] [Indexed: 06/28/2024]
Abstract
Suppressor tRNAs are engineered or naturally occurring transfer RNA molecules that have shown promise in gene therapy for diseases caused by nonsense mutations, which result in premature termination codons (PTCs) in coding sequence, leading to truncated, often nonfunctional proteins. Suppressor tRNAs can recognize and pair with these PTCs, allowing the ribosome to continue translation and produce a full-length protein. This review introduces the mechanism and development of suppressor tRNAs, compares suppressor tRNAs with other readthrough therapies, discusses their potential for clinical therapy, limitations, and obstacles. We also summarize the applications of suppressor tRNAs in both in vitro and in vivo, offering new insights into the research and treatment of nonsense mutation diseases.
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Affiliation(s)
- Jingjing Ruan
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Liangzhu Laboratory, Hangzhou, 310000, China
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Xiaoxiao Yu
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Huixia Xu
- Department of Thoracic and Cardiovascular Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Wenrui Cui
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Kaiye Zhang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Chenyang Liu
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Wenlong Sun
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Xiaodan Huang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Lei An
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China.
| | - Yue Zhang
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Liangzhu Laboratory, Hangzhou, 310000, China.
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China.
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China.
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Clark ZS, O'Connor M. Suppressor analysis links trans-translation and ribosomal protein uS7 to RluD function in Escherichia coli. Biochem Biophys Res Commun 2024; 700:149584. [PMID: 38295647 PMCID: PMC10878134 DOI: 10.1016/j.bbrc.2024.149584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 01/25/2024] [Indexed: 02/17/2024]
Abstract
The pseudouridine (ψ) synthase, RluD is responsible for three ψ modifications in the helix 69 (H69) of bacterial 23S rRNA. While normally dispensable, rluD becomes critical for rapid cell growth in bacteria that are defective in translation-termination. In slow-growing rluD- bacteria, suppressors affecting termination factors RF2 and RF3 arise frequently and restore normal termination and rapid cell growth. Here we describe two weaker suppressors, affecting rpsG, encoding ribosomal protein uS7 and ssrA, encoding tmRNA. In K-12 strains of E. coli, rpsG terminates at a TGA codon. In the suppressor strain, alteration of an upstream CAG to a TAG stop codon results in a shortened uS7 and partial alleviation of slow growth, likely by replacing an inefficient TGA stop codon with the more efficient TAG. Inefficient termination events, such as occurs in some rluD- strains, are targeted by trans-translation. Inactivation of the ssrA gene in slow-growing, termination-defective mutants lacking RluD and RF3, also partially restores robust growth, most probably by preventing destruction of completed polypeptides on ribosomes at slow-terminating stop codons. Finally, an additional role for RluD has been proposed, independent of its pseudouridine synthase activity. This is based on the observation that plasmids expressing catalytically dead (D139N or D139T) RluD proteins could nonetheless restore robust growth to an E. coli K-12 rluD- mutant. However, newly constructed D139N and D139T rluD plasmids do not have any growth-restoring activity and the original observations were likely due to the appearance of suppressors.
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Affiliation(s)
- Zachary S Clark
- Division of Biology and Biomedical Systems, School of Science and Engineering, 306 Spencer Hall, University of Missouri-Kansas City, 5007 Rockhill Rd., Kansas City, MO, 64110, USA
| | - Michael O'Connor
- Division of Biology and Biomedical Systems, School of Science and Engineering, 306 Spencer Hall, University of Missouri-Kansas City, 5007 Rockhill Rd., Kansas City, MO, 64110, USA.
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Chabronova A, van den Akker G, Housmans BAC, Caron MMJ, Cremers A, Surtel DAM, Peffers MJ, van Rhijn LW, Marchand V, Motorin Y, Welting TJM. Depletion of SNORA33 Abolishes ψ of 28S-U4966 and Affects the Ribosome Translational Apparatus. Int J Mol Sci 2023; 24:12578. [PMID: 37628759 PMCID: PMC10454564 DOI: 10.3390/ijms241612578] [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: 07/05/2023] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Eukaryotic ribosomes are complex molecular nanomachines translating genetic information from mRNAs into proteins. There is natural heterogeneity in ribosome composition. The pseudouridylation (ψ) of ribosomal RNAs (rRNAs) is one of the key sources of ribosome heterogeneity. Nevertheless, the functional consequences of ψ-based ribosome heterogeneity and its relevance for human disease are yet to be understood. Using HydraPsiSeq and a chronic disease model of non-osteoarthritic primary human articular chondrocytes exposed to osteoarthritic synovial fluid, we demonstrated that the disease microenvironment is capable of instigating site-specific changes in rRNA ψ profiles. To investigate one of the identified differential rRNA ψ sites (28S-ψ4966), we generated SNORA22 and SNORA33 KO SW1353 cell pools using LentiCRISPRv2/Cas9 and evaluated the ribosome translational capacity by 35S-Met/Cys incorporation, assessed the mode of translation initiation and ribosomal fidelity using dual luciferase reporters, and assessed cellular and ribosomal proteomes by LC-MS/MS. We uncovered that the depletion of SNORA33, but not SNORA22, reduced 28S-ψ4966 levels. The resulting loss of 28S-ψ4966 affected ribosomal protein composition and function and led to specific changes in the cellular proteome. Overall, our pioneering findings demonstrate that cells dynamically respond to disease-relevant changes in their environment by altering their rRNA pseudouridylation profiles, with consequences for ribosome function and the cellular proteome relevant to human disease.
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Affiliation(s)
- Alzbeta Chabronova
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Guus van den Akker
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Bas A. C. Housmans
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Marjolein M. J. Caron
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Andy Cremers
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Don A. M. Surtel
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Mandy J. Peffers
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L8 7TX, UK
| | - Lodewijk W. van Rhijn
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
| | - Virginie Marchand
- UAR2008 IBSLor CNRS-INSERM-Université de Lorraine, F54000 Nancy, France
| | - Yuri Motorin
- UAR2008 IBSLor CNRS-INSERM-Université de Lorraine, F54000 Nancy, France
- UMR7365 IMOPA, CNRS-Université de Lorraine, F54000 Nancy, France
| | - Tim J. M. Welting
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, 6229 HX Maastricht, The Netherlands; (A.C.); (B.A.C.H.)
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University Medical Center+ (MUMC+), 6229 HX Maastricht, The Netherlands
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Porat J, Kothe U, Bayfield MA. Revisiting tRNA chaperones: New players in an ancient game. RNA (NEW YORK, N.Y.) 2021; 27:rna.078428.120. [PMID: 33593999 PMCID: PMC8051267 DOI: 10.1261/rna.078428.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/10/2021] [Indexed: 05/03/2023]
Abstract
tRNAs undergo an extensive maturation process including post-transcriptional modifications that influence secondary and tertiary interactions. Precursor and mature tRNAs lacking key modifications are often recognized as aberrant and subsequently targeted for decay, illustrating the importance of modifications in promoting structural integrity. tRNAs also rely on tRNA chaperones to promote the folding of misfolded substrates into functional conformations. The best characterized tRNA chaperone is the La protein, which interacts with nascent RNA polymerase III transcripts to promote folding and offers protection from exonucleases. More recently, certain tRNA modification enzymes have also been demonstrated to possess tRNA folding activity distinct from their catalytic activity, suggesting that they may act as tRNA chaperones. In this review, we will discuss pioneering studies relating post-transcriptional modification to tRNA stability and decay pathways, present recent advances into the mechanism by which the RNA chaperone La assists pre-tRNA maturation, and summarize emerging research directions aimed at characterizing modification enzymes as tRNA chaperones. Together, these findings shed light on the importance of tRNA folding and how tRNA chaperones, in particular, increase the fraction of nascent pre-tRNAs that adopt a folded, functional conformation.
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Abdalaal H, Pundir S, Ge X, Sanyal S, Näsvall J. Collateral Toxicity Limits the Evolution of Bacterial Release Factor 2 toward Total Omnipotence. Mol Biol Evol 2020; 37:2918-2930. [PMID: 32437534 PMCID: PMC7530605 DOI: 10.1093/molbev/msaa129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
When new genes evolve through modification of existing genes, there are often tradeoffs between the new and original functions, making gene duplication and amplification necessary to buffer deleterious effects on the original function. We have used experimental evolution of a bacterial strain lacking peptide release factor 1 (RF1) in order to study how peptide release factor 2 (RF2) evolves to compensate the loss of RF1. As expected, amplification of the RF2-encoding gene prfB to high copy number was a rapid initial response, followed by the appearance of mutations in RF2 and other components of the translation machinery. Characterization of the evolved RF2 variants by their effects on bacterial growth rate, reporter gene expression, and in vitro translation termination reveals a complex picture of reduced discrimination between the cognate and near-cognate stop codons and highlights a functional tradeoff that we term "collateral toxicity." We suggest that this type of tradeoff may be a more serious obstacle in new gene evolution than the more commonly discussed evolutionary tradeoffs between "old" and "new" functions of a gene, as it cannot be overcome by gene copy number changes. Further, we suggest a model for how RF2 autoregulation responds to alterations in the demand not only for RF2 activity but also for RF1 activity.
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Affiliation(s)
- Hind Abdalaal
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Shreya Pundir
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Xueliang Ge
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Suparna Sanyal
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Joakim Näsvall
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
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Fujikane R, Behm-Ansmant I, Tillault AS, Loegler C, Igel-Bourguignon V, Marguet E, Forterre P, Branlant C, Motorin Y, Charpentier B. Contribution of protein Gar1 to the RNA-guided and RNA-independent rRNA:Ψ-synthase activities of the archaeal Cbf5 protein. Sci Rep 2018; 8:13815. [PMID: 30218085 PMCID: PMC6138745 DOI: 10.1038/s41598-018-32164-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/29/2018] [Indexed: 01/09/2023] Open
Abstract
Archaeal RNA:pseudouridine-synthase (PUS) Cbf5 in complex with proteins L7Ae, Nop10 and Gar1, and guide box H/ACA sRNAs forms ribonucleoprotein (RNP) catalysts that insure the conversion of uridines into pseudouridines (Ψs) in ribosomal RNAs (rRNAs). Nonetheless, in the absence of guide RNA, Cbf5 catalyzes the in vitro formation of Ψ2603 in Pyrococcus abyssi 23S rRNA and of Ψ55 in tRNAs. Using gene-disrupted strains of the hyperthermophilic archaeon Thermococcus kodakarensis, we studied the in vivo contribution of proteins Nop10 and Gar1 to the dual RNA guide-dependent and RNA-independent activities of Cbf5 on 23S rRNA. The single-null mutants of the cbf5, nop10, and gar1 genes are viable, but display a thermosensitive slow growth phenotype. We also generated a single-null mutant of the gene encoding Pus10, which has redundant activity with Cbf5 for in vitro formation of Ψ55 in tRNA. Analysis of the presence of Ψs within the rRNA peptidyl transferase center (PTC) of the mutants demonstrated that Cbf5 but not Pus10 is required for rRNA modification. Our data reveal that, in contrast to Nop10, Gar1 is crucial for in vivo and in vitro RNA guide-independent formation of Ψ2607 (Ψ2603 in P. abyssi) by Cbf5. Furthermore, our data indicate that pseudouridylation at orphan position 2589 (2585 in P. abyssi), for which no PUS or guide sRNA has been identified so far, relies on RNA- and Gar1-dependent activity of Cbf5.
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Affiliation(s)
- Ryosuke Fujikane
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
- Fukuoka Dental College, Department of Physiological Sciences and Molecular Biology, Section of Cellular and Molecular Regulation, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Isabelle Behm-Ansmant
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
| | - Anne-Sophie Tillault
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Christine Loegler
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
| | - Valérie Igel-Bourguignon
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
| | - Evelyne Marguet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Patrick Forterre
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
- Institut Pasteur, Département de Microbiologie, 25 rue du Dr Roux, F-7505, Paris, France
| | - Christiane Branlant
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
| | - Yuri Motorin
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France
- Université de Lorraine, CNRS, INSERM, UMS2008 IBSLor, F-54500, Nancy, France
| | - Bruno Charpentier
- Université de Lorraine, CNRS, UMR 7365 Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), F-54500, Nancy, France.
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Leppik M, Liiv A, Remme J. Random pseuoduridylation in vivo reveals critical region of Escherichia coli 23S rRNA for ribosome assembly. Nucleic Acids Res 2017; 45:6098-6108. [PMID: 28334881 PMCID: PMC5449589 DOI: 10.1093/nar/gkx160] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/20/2017] [Accepted: 02/27/2017] [Indexed: 12/18/2022] Open
Abstract
Pseudouridine is the most common modified nucleoside in RNA, which is found in stable RNA species and in eukaryotic mRNAs. Functional analysis of pseudouridine is complicated by marginal effect of its absence. We demonstrate that excessive pseudouridines in rRNA inhibit ribosome assembly. Ten-fold increase of pseudouridines in the 16S and 23S rRNA made by a chimeric pseudouridine synthase leads to accumulation of the incompletely assembled large ribosome subunits. Hyper modified 23S rRNA is found in the r-protein assembly defective particles and are selected against in the 70S and polysome fractions showing modification interference. Eighteen positions of 23S rRNA were identified where isomerization of uridines interferes with ribosome assembly. Most of the interference sites are located in the conserved core of the large subunit, in the domain 0 of 23S rRNA, around the peptide exit tunnel. A plausible reason for pseudouridine-dependent inhibition of ribosome assembly is stabilization of rRNA structure, which leads to the folding traps of rRNA and to the retardation of the ribosome assembly.
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Affiliation(s)
- Margus Leppik
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Aivar Liiv
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Jaanus Remme
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
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Abstract
The bacterial ribosome is a complex macromolecular machine that deciphers the genetic code with remarkable fidelity. During the elongation phase of protein synthesis, the ribosome selects aminoacyl-tRNAs as dictated by the canonical base pairing between the anticodon of the tRNA and the codon of the messenger RNA. The ribosome's participation in tRNA selection is active rather than passive, using conformational changes of conserved bases of 16S rRNA to directly monitor the geometry of codon-anticodon base pairing. The tRNA selection process is divided into an initial selection step and a subsequent proofreading step, with the utilization of two sequential steps increasing the discriminating power of the ribosome far beyond that which could be achieved based on the thermodynamics of codon-anticodon base pairing stability. The accuracy of decoding is impaired by a number of antibiotics and can be either increased or decreased by various mutations in either subunit of the ribosome, in elongation factor Tu, and in tRNA. In this chapter we will review our current understanding of various forces that determine the accuracy of decoding by the bacterial ribosome.
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Tillault AS, Fourmann JB, Loegler C, Wieden HJ, Kothe U, Charpentier B. Contribution of two conserved histidines to the dual activity of archaeal RNA guide-dependent and -independent pseudouridine synthase Cbf5. RNA (NEW YORK, N.Y.) 2015; 21:1233-1239. [PMID: 25990001 PMCID: PMC4478342 DOI: 10.1261/rna.051425.115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 04/09/2015] [Indexed: 06/01/2023]
Abstract
In all organisms, several distinct stand-alone pseudouridine synthase (PUS) family enzymes are expressed to isomerize uridine into pseudouridine (Ψ) by specific recognition of RNAs. In addition, Ψs are generated in Archaea and Eukaryotes by PUS enzymes which are organized as ribonucleoprotein particles (RNP)--the box H/ACA s/snoRNPs. For this modification system, a unique TruB-like catalytic PUS subunit is associated with various RNA guides which specifically target and secure substrate RNAs by base-pairing. The archaeal Cbf5 PUS displays the special feature of exhibiting both RNA guide-dependent and -independent activities. Structures of substrate-bound TruB and H/ACA sRNP revealed the importance of histidines in positioning the target uridine in the active site. To analyze the respective role of H60 and H77, we have generated variants carrying alanine substitutions at these positions. The impact of the mutations was analyzed for unguided modifications U(55) in tRNA and U2603 in 23S rRNA, and for activity of the box H/ACA Pab91 sRNP enzyme. H77 (H43 in TruB), but not H60, appeared to be crucial for the RNA guide-independent activity. In contrast to earlier suggestions, H60 was found to be noncritical for the activity of the H/ACA sRNP, but contributes together with H77 to the full activity of H/ACA sRNPs. The data suggest that a similar catalytic process was conserved in the two divergent pseudouridylation systems.
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Affiliation(s)
- Anne-Sophie Tillault
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS Université de Lorraine, Biopôle de l'Université de Lorraine, Campus Biologie Santé, 54505 Vandœuvre-lès-Nancy, France
| | - Jean-Baptiste Fourmann
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS Université de Lorraine, Biopôle de l'Université de Lorraine, Campus Biologie Santé, 54505 Vandœuvre-lès-Nancy, France
| | - Christine Loegler
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS Université de Lorraine, Biopôle de l'Université de Lorraine, Campus Biologie Santé, 54505 Vandœuvre-lès-Nancy, France
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Ute Kothe
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Bruno Charpentier
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS Université de Lorraine, Biopôle de l'Université de Lorraine, Campus Biologie Santé, 54505 Vandœuvre-lès-Nancy, France
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10
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Saliou JM, Manival X, Tillault AS, Atmanene C, Bobo C, Branlant C, Van Dorsselaer A, Charpentier B, Cianférani S. Combining native MS approaches to decipher archaeal box H/ACA ribonucleoprotein particle structure and activity. Proteomics 2015; 15:2851-61. [DOI: 10.1002/pmic.201400529] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 02/06/2015] [Accepted: 02/24/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Jean-Michel Saliou
- BioOrganic Mass Spectrometry Laboratory (LSMBO); IPHC; Université de Strasbourg; Strasbourg France
- IPHC; CNRS UMR 7178; Strasbourg France
| | - Xavier Manival
- Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA); UMR 7365 CNRS Université de Lorraine; Biopôle Vandœuvre-lès-Nancy France
| | - Anne-Sophie Tillault
- Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA); UMR 7365 CNRS Université de Lorraine; Biopôle Vandœuvre-lès-Nancy France
| | - Cédric Atmanene
- BioOrganic Mass Spectrometry Laboratory (LSMBO); IPHC; Université de Strasbourg; Strasbourg France
- IPHC; CNRS UMR 7178; Strasbourg France
| | - Claude Bobo
- Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA); UMR 7365 CNRS Université de Lorraine; Biopôle Vandœuvre-lès-Nancy France
| | - Christiane Branlant
- Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA); UMR 7365 CNRS Université de Lorraine; Biopôle Vandœuvre-lès-Nancy France
| | - Alain Van Dorsselaer
- BioOrganic Mass Spectrometry Laboratory (LSMBO); IPHC; Université de Strasbourg; Strasbourg France
- IPHC; CNRS UMR 7178; Strasbourg France
| | - Bruno Charpentier
- Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA); UMR 7365 CNRS Université de Lorraine; Biopôle Vandœuvre-lès-Nancy France
| | - Sarah Cianférani
- BioOrganic Mass Spectrometry Laboratory (LSMBO); IPHC; Université de Strasbourg; Strasbourg France
- IPHC; CNRS UMR 7178; Strasbourg France
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High-resolution structure of the Escherichia coli ribosome. Nat Struct Mol Biol 2015; 22:336-41. [PMID: 25775265 PMCID: PMC4429131 DOI: 10.1038/nsmb.2994] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 02/19/2015] [Indexed: 01/21/2023]
Abstract
Protein synthesis by the ribosome is highly dependent on the ionic conditions in the cellular environment, but the roles of ribosome solvation remain poorly understood. Moreover, the function of modifications to ribosomal RNA and ribosomal proteins are unclear. Here we present the structure of the Escherichia coli 70S ribosome to 2.4 Å resolution. The structure reveals details of the ribosomal subunit interface that are conserved in all domains of life, and suggest how solvation contributes to ribosome integrity and function. The structure also suggests how the conformation of ribosomal protein uS12 likely impacts its contribution to messenger RNA decoding. This structure helps to explain the phylogenetic conservation of key elements of the ribosome, including posttranscriptional and posttranslational modifications and should serve as a basis for future antibiotic development.
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12
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Sergeeva OV, Bogdanov AA, Sergiev PV. What do we know about ribosomal RNA methylation in Escherichia coli? Biochimie 2014; 117:110-8. [PMID: 25511423 DOI: 10.1016/j.biochi.2014.11.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 11/20/2014] [Indexed: 11/18/2022]
Abstract
A ribosome is a ribonucleoprotein that performs the synthesis of proteins. Ribosomal RNA of all organisms includes a number of modified nucleotides, such as base or ribose methylated and pseudouridines. Methylated nucleotides are highly conserved in bacteria and some even universally. In this review we discuss available data on a set of modification sites in the most studied bacteria, Escherichia coli. While most rRNA modification enzymes are known for this organism, the function of the modified nucleotides is rarely identified.
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MESH Headings
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Escherichia coli Proteins/chemistry
- Escherichia coli Proteins/metabolism
- Methylation
- Methyltransferases/chemistry
- Methyltransferases/metabolism
- Models, Molecular
- Nucleic Acid Conformation
- Protein Binding
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
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Affiliation(s)
- O V Sergeeva
- Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia; Skolkovo Institute of Science and Technology, Skolkovo, Moscow 143025, Russia.
| | - A A Bogdanov
- Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - P V Sergiev
- Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
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13
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Feng B, Mandava CS, Guo Q, Wang J, Cao W, Li N, Zhang Y, Zhang Y, Wang Z, Wu J, Sanyal S, Lei J, Gao N. Structural and functional insights into the mode of action of a universally conserved Obg GTPase. PLoS Biol 2014; 12:e1001866. [PMID: 24844575 PMCID: PMC4028186 DOI: 10.1371/journal.pbio.1001866] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/10/2014] [Indexed: 01/13/2023] Open
Abstract
Kinetics and cryo-electronmicroscopy data provide insights into GTPase ObgE’s role as a ribosome anti-association factor that is modulated by nutrient availability, coupling growth control to ribosome biosynthesis and protein translation. Obg proteins are a family of P-loop GTPases, conserved from bacteria to human. The Obg protein in Escherichia coli (ObgE) has been implicated in many diverse cellular functions, with proposed molecular roles in two global processes, ribosome assembly and stringent response. Here, using pre-steady state fast kinetics we demonstrate that ObgE is an anti-association factor, which prevents ribosomal subunit association and downstream steps in translation by binding to the 50S subunit. ObgE is a ribosome dependent GTPase; however, upon binding to guanosine tetraphosphate (ppGpp), the global regulator of stringent response, ObgE exhibits an enhanced interaction with the 50S subunit, resulting in increased equilibrium dissociation of the 70S ribosome into subunits. Furthermore, our cryo-electron microscopy (cryo-EM) structure of the 50S·ObgE·GMPPNP complex indicates that the evolutionarily conserved N-terminal domain (NTD) of ObgE is a tRNA structural mimic, with specific interactions with peptidyl-transferase center, displaying a marked resemblance to Class I release factors. These structural data might define ObgE as a specialized translation factor related to stress responses, and provide a framework towards future elucidation of functional interplay between ObgE and ribosome-associated (p)ppGpp regulators. Together with published data, our results suggest that ObgE might act as a checkpoint in final stages of the 50S subunit assembly under normal growth conditions. And more importantly, ObgE, as a (p)ppGpp effector, might also have a regulatory role in the production of the 50S subunit and its participation in translation under certain stressed conditions. Thus, our findings might have uncovered an under-recognized mechanism of translation control by environmental cues. GTPases commonly act as molecular switches in biological systems. By oscillating between two conformational states, depending on the type of guanine nucleotide bound (GTP or GDP), GTPases are essential regulators of many aspects of cell biology. Additional levels of regulation can be acquired through the synthesis of other guanine nucleotide derivatives that target GTPases; for instance, when nutrients are limited, bacterial cells produce guanine tetraphosphate/pentaphosphate—(p)ppGpp—as part of the “stringent response” to adjust the balance between growth and survival. ObgE is a GTPase with many reported cellular functions that include ribosome biogenesis, but none of its functions is understood at the molecular level. Here we characterize, both biochemically and structurally, the binding of ObgE to its cellular partner, the 50S ribosomal subunit. Our results show that ObgE is an anti-association factor, which binds to the 50S subunit to block the formation of the 70S ribosome, thereby inhibiting the initiation of translation. Furthermore, the binding and anti-association activities of ObgE are regulated by guanine nucleotides, as well as by (p)ppGpp. We thus propose that ObgE is a checkpoint protein in the assembly of the 50S subunit, which senses the cellular energy stress via levels of (p)ppGpp and links ribosome assembly to other global growth control pathways.
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Affiliation(s)
- Boya Feng
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | | | - Qiang Guo
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jie Wang
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Wei Cao
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ningning Li
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yixiao Zhang
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanqing Zhang
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhixin Wang
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiawei Wu
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Suparna Sanyal
- Department of Cell and Molecular Biology, Uppsala University, BMC, Uppsala, Sweden
- * E-mail: (NG); (JL); (SS)
| | - Jianlin Lei
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (NG); (JL); (SS)
| | - Ning Gao
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (NG); (JL); (SS)
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14
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Spenkuch F, Motorin Y, Helm M. Pseudouridine: still mysterious, but never a fake (uridine)! RNA Biol 2014; 11:1540-54. [PMID: 25616362 PMCID: PMC4615568 DOI: 10.4161/15476286.2014.992278] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/23/2014] [Accepted: 10/10/2014] [Indexed: 01/15/2023] Open
Abstract
Pseudouridine (Ψ) is the most abundant of >150 nucleoside modifications in RNA. Although Ψ was discovered as the first modified nucleoside more than half a century ago, neither the enzymatic mechanism of its formation, nor the function of this modification are fully elucidated. We present the consistent picture of Ψ synthases, their substrates and their substrate positions in model organisms of all domains of life as it has emerged to date and point out the challenges that remain concerning higher eukaryotes and the elucidation of the enzymatic mechanism.
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MESH Headings
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Humans
- Intramolecular Transferases/genetics
- Intramolecular Transferases/metabolism
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Nucleic Acid Conformation
- Pseudouridine/metabolism
- RNA/genetics
- RNA/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Mitochondrial
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer, Amino Acid-Specific/chemistry
- RNA, Transfer, Amino Acid-Specific/genetics
- RNA, Transfer, Amino Acid-Specific/metabolism
- Ribonucleoproteins, Small Nuclear/genetics
- Ribonucleoproteins, Small Nuclear/metabolism
- Ribosomes/chemistry
- Ribosomes/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Uridine/metabolism
- RNA, Guide, CRISPR-Cas Systems
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Affiliation(s)
- Felix Spenkuch
- Institute of Pharmacy and Biochemistry; Johannes Gutenberg-University of Mainz; Mainz, Germany
| | - Yuri Motorin
- Laboratoire IMoPA; Ingénierie Moléculaire et Physiopathologie Articulaire; BioPôle de l'Université de Lorraine; Campus Biologie-Santé; Faculté de Médecine; Vandoeuvre-les-Nancy Cedex, France
| | - Mark Helm
- Institute of Pharmacy and Biochemistry; Johannes Gutenberg-University of Mainz; Mainz, Germany
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15
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Wang J, Mei H, Qian H, Tang Q, Liu X, Yu Z, He J. Expression profile and regulation of spore and parasporal crystal formation-associated genes in Bacillus thuringiensis. J Proteome Res 2013; 12:5487-501. [PMID: 24215520 DOI: 10.1021/pr4003728] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bacillus thuringiensis, a Gram-positive endospore-forming bacterium, is characterized by the formation of parasporal crystals consisting of insecticidal crystal proteins (ICPs) during sporulation. We reveal gene expression profiles and regulatory mechanisms associated with spore and parasporal crystal formation based on transcriptomics and proteomics data of B. thuringiensis strain CT-43. During sporulation, five ICP genes encoded by CT-43 were specifically transcribed; moreover, most of the spore structure-, assembly-, and maturation-associated genes were specifically expressed or significantly up-regulated, with significant characteristics of temporal regulation. These findings suggest that it is essential for the cell to maintain efficient operation of transcriptional and translational machinery during sporulation. Our results indicate that the RNA polymerase complex δ and ω subunits, cold shock proteins, sigma factors, and transcriptional factors as well as the E2 subunit of the pyruvate dehydrogenase complex could cooperatively participate in transcriptional regulation via different mechanisms. In particular, differences in processing and modification of ribosomal proteins, rRNA, and tRNA combined with derepression of translational inhibition could boost the rate of ribosome recycling and assembly as well as translation initiation, elongation, and termination efficiency, thereby compensating for the reduction in ribosomal levels. The efficient operation of translational machineries and powerful protein-quality controlling systems would thus ensure biosyntheses of a large quantity of proteins with normal biological functions during sporulation.
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Affiliation(s)
- Jieping Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University , No. 1 Shizishan Street, Wuhan, Hubei 430070, China
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16
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Russell SP, Limbach PA. Evaluating the reproducibility of quantifying modified nucleosides from ribonucleic acids by LC-UV-MS. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 923-924:74-82. [PMID: 23500350 DOI: 10.1016/j.jchromb.2013.02.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 02/07/2013] [Accepted: 02/11/2013] [Indexed: 11/26/2022]
Abstract
Post-transcriptional chemical covalent modification of adenosine, guanosine, uridine and cytidine occurs frequently in all types of ribonucleic acids (RNAs). In ribosomal RNA (rRNA) and transfer RNA (tRNA) these modifications make important contributions to RNA structure and stability and to the accuracy and efficiency of protein translation. The functional dynamics, synergistic nature and regulatory roles of these posttranscriptional nucleoside modifications within the cell are not well characterized. These modifications are present at very low levels and isolation of individual nucleosides for analysis requires a complex multi-step approach. The focus of this study is to characterize the reproducibility of a liquid chromatography method used to isolate and quantitatively characterize modified nucleosides in tRNA and rRNA when nucleoside detection is performed using ultraviolet and mass spectrometric detection (UV and MS, respectively). Despite the analytical challenges of sample isolation and dynamic range, quantitative profiling of modified nucleosides obtained from bacterial tRNAs and rRNAs is feasible at relative standard deviations of 5% RSD or less.
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Affiliation(s)
- Susan P Russell
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, United States
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17
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Fourmann JB, Tillault AS, Blaud M, Leclerc F, Branlant C, Charpentier B. Comparative study of two box H/ACA ribonucleoprotein pseudouridine-synthases: relation between conformational dynamics of the guide RNA, enzyme assembly and activity. PLoS One 2013; 8:e70313. [PMID: 23922977 PMCID: PMC3726423 DOI: 10.1371/journal.pone.0070313] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/18/2013] [Indexed: 11/22/2022] Open
Abstract
Multiple RNA-guided pseudouridine synthases, H/ACA ribonucleoprotein particles (RNPs) which contain a guide RNA and four proteins, catalyze site-specific post-transcriptional isomerization of uridines into pseudouridines in substrate RNAs. In archaeal particles, the guide small RNA (sRNA) is anchored by the pseudouridine synthase aCBF5 and the ribosomal protein L7Ae. Protein aNOP10 interacts with both aCBF5 and L7Ae. The fourth protein, aGAR1, interacts with aCBF5 and enhances catalytic efficiency. Here, we compared the features of two H/ACA sRNAs, Pab21 and Pab91, from Pyrococcus abyssi. We found that aCBF5 binds much more weakly to Pab91 than to Pab21. Surprisingly, the Pab91 sRNP exhibits a higher catalytic efficiency than the Pab21 sRNP. We thus investigated the molecular basis of the differential efficiencies observed for the assembly and catalytic activity of the two enzymes. For this, we compared profiles of the extent of lead-induced cleavages in these sRNAs during a stepwise reconstitution of the sRNPs, and analyzed the impact of the absence of the aNOP10–L7Ae interaction. Such probing experiments indicated that the sRNAs undergo a series of conformational changes upon RNP assembly. These changes were also evaluated directly by circular dichroism (CD) spectroscopy, a tool highly adapted to analyzing RNA conformational dynamics. In addition, our results reveal that the conformation of helix P1 formed at the base of the H/ACA sRNAs is optimized in Pab21 for efficient aCBF5 binding and RNP assembly. Moreover, P1 swapping improved the assembly of the Pab91 sRNP. Nonetheless, efficient aCBF5 binding probably also relies on the pseudouridylation pocket which is not optimized for high activity in the case of Pab21.
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Affiliation(s)
- Jean-Baptiste Fourmann
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Anne-Sophie Tillault
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Magali Blaud
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Fabrice Leclerc
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Christiane Branlant
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Bruno Charpentier
- Laboratoire Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Unité Mixte de Recherche Centre National de la Recherche Scientifique - Université de Lorraine, Biopôle de l’Université de Lorraine, Vandœuvre-lès-Nancy, France
- * E-mail:
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18
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Jiang J, Sakakibara Y, Chow CS. Helix 69: A Multitasking RNA Motif as a Novel Drug Target. Isr J Chem 2013. [DOI: 10.1002/ijch.201300012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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19
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Leppik M, Ero R, Liiv A, Kipper K, Remme J. Different sensitivity of H69 modification enzymes RluD and RlmH to mutations in Escherichia coli 23S rRNA. Biochimie 2012; 94:1080-9. [PMID: 22586702 DOI: 10.1016/j.biochi.2012.02.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nucleoside modifications are introduced into the ribosomal RNA during the assembly of the ribosome. The number and the localization of the modified nucleosides in rRNAs are known for several organisms. In bacteria, rRNA modified nucleosides are synthesized by a set of specific enzymes, the majority of which have been identified in Escherichia coli. Each rRNA modification enzyme recognizes its substrate nucleoside(s) at a specific stage of ribosome assembly. Not much is known about the specificity determinants involved in the substrate recognition of the modification enzymes. In order to shed light on the substrate specificity of RluD and RlmH, the enzymes responsible for the introduction of modifications into the stem-loop 69 (H69), we monitored the formation of H69 pseudouridines (Ψ) and methylated pseudouridine (m3Ψ) in vitro on ribosomes with alterations in 23S rRNA. While the synthesis of Ψs in H69 by RluD is relatively insensitive to the point mutations at neighboring positions, methylation of one of the Ψs by RlmH exhibited a much stronger sensitivity. Apparently, in spite of synthesizing modifications in the same region or even at the same position of rRNA, the two enzymes employ different substrate recognition mechanisms.
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Affiliation(s)
- Margus Leppik
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
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20
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Burakovsky DE, Prokhorova IV, Sergiev PV, Milón P, Sergeeva OV, Bogdanov AA, Rodnina MV, Dontsova OA. Impact of methylations of m2G966/m5C967 in 16S rRNA on bacterial fitness and translation initiation. Nucleic Acids Res 2012; 40:7885-95. [PMID: 22649054 PMCID: PMC3439901 DOI: 10.1093/nar/gks508] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The functional centers of the ribosome in all organisms contain ribosomal RNA (rRNA) modifications, which are introduced by specialized enzymes and come at an energy cost for the cell. Surprisingly, none of the modifications tested so far was essential for growth and hence the functional role of modifications is largely unknown. Here, we show that the methyl groups of nucleosides m2G966 and m5C967 of 16S rRNA in Escherichia coli are important for bacterial fitness. In vitro analysis of all phases of translation suggests that the m2G966/m5C967 modifications are dispensable for elongation, termination and ribosome recycling. Rather, the modifications modulate the early stages of initiation by stabilizing the binding of fMet-tRNAfMet to the 30S pre-initiation complex prior to start-codon recognition. We propose that the m2G966 and m5C967 modifications help shaping the bacterial proteome, most likely by fine-tuning the rates that determine the fate of a given messenger RNA (mRNA) at early checkpoints of mRNA selection.
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21
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Sakakibara Y, Chow CS. Role of pseudouridine in structural rearrangements of helix 69 during bacterial ribosome assembly. ACS Chem Biol 2012; 7:871-8. [PMID: 22324880 DOI: 10.1021/cb200497q] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
As part of the central core domain of the ribosome, helix 69 of 23S rRNA participates in an important intersubunit bridge and contacts several protein translation factors. Helix 69 is believed to play key roles in protein synthesis. Even though high-resolution crystal structures of the ribosome exist, the solution dynamics and roles of individual nucleotides in H69 are still not well-defined. To better understand the influence of modified nucleotides, specifically pseudouridine, on the multiple conformational states of helix 69 in the context of 50S subunits and 70S ribosomes, chemical probing analyses were performed on wild-type and pseudouridine-deficient bacterial ribosomes. Local structural rearrangements of helix 69 upon ribosomal subunit association and interactions with its partner, helix 44 of 16S rRNA, are observed. The helix 69 conformational states are also magnesium-dependent. The probing data presented in this study provide insight into the functional role of helix 69 dynamics and regulation of these conformational states by post-transcriptional pseudouridine modification.
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Affiliation(s)
- Yogo Sakakibara
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United
States
| | - Christine S. Chow
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United
States
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22
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Kimura S, Ikeuchi Y, Kitahara K, Sakaguchi Y, Suzuki T, Suzuki T. Base methylations in the double-stranded RNA by a fused methyltransferase bearing unwinding activity. Nucleic Acids Res 2012; 40:4071-85. [PMID: 22210896 PMCID: PMC3351187 DOI: 10.1093/nar/gkr1287] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 11/28/2011] [Accepted: 12/14/2011] [Indexed: 12/18/2022] Open
Abstract
Modifications of rRNAs are clustered in functional regions of the ribosome. In Helix 74 of Escherichia coli 23S rRNA, guanosines at positions 2069 and 2445 are modified to 7-methylguanosine(m(7)G) and N(2)-methylguanosine(m(2)G), respectively. We searched for the gene responsible for m(7)G2069 formation, and identified rlmL, which encodes the methyltransferase for m(2)G2445, as responsible for the biogenesis of m(7)G2069. In vitro methylation of rRNA revealed that rlmL encodes a fused methyltransferase responsible for forming both m(7)G2069 and m(2)G2445. We renamed the gene rlmKL. The N-terminal RlmL activity for m(2)G2445 formation was significantly enhanced by the C-terminal RlmK. Moreover, RlmKL had an unwinding activity of Helix 74, facilitating cooperative methylations of m(7)G2069 and m(2)G2445 during biogenesis of 50S subunit. In fact, we observed that RlmKL was involved in the efficient assembly of 50S subunit in a mutant strain lacking an RNA helicase deaD.
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MESH Headings
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Escherichia coli Proteins/chemistry
- Escherichia coli Proteins/metabolism
- Guanosine/analogs & derivatives
- Guanosine/metabolism
- Methylation
- Methyltransferases/chemistry
- Methyltransferases/metabolism
- Models, Molecular
- Protein Structure, Tertiary
- RNA Helicases/metabolism
- RNA, Double-Stranded/chemistry
- RNA, Double-Stranded/metabolism
- RNA, Ribosomal, 23S/chemistry
- RNA, Ribosomal, 23S/metabolism
- Ribosome Subunits, Large, Bacterial/metabolism
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Affiliation(s)
| | | | | | | | | | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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23
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Sergiev PV, Golovina AY, Sergeeva OV, Osterman IA, Nesterchuk MV, Bogdanov AA, Dontsova OA. How much can we learn about the function of bacterial rRNA modification by mining large-scale experimental datasets? Nucleic Acids Res 2012; 40:5694-705. [PMID: 22411911 PMCID: PMC3384335 DOI: 10.1093/nar/gks219] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Modification of ribosomal RNA is ubiquitous among living organisms. Its functional role is well established for only a limited number of modified nucleotides. There are examples of rRNA modification involvement in the gene expression regulation in the cell. There is a need for large data set analysis in the search for potential functional partners for rRNA modification. In this study, we extracted phylogenetic profile, genome neighbourhood, co-expression and phenotype profile and co-purification data regarding Escherichia coli rRNA modification enzymes from public databases. Results were visualized as graphs using Cytoscape and analysed. Majority linked genes/proteins belong to translation apparatus. Among co-purification partners of rRNA modification enzymes are several candidates for experimental validation. Phylogenetic profiling revealed links of pseudouridine synthetases with RF2, RsmH with translation factors IF2, RF1 and LepA and RlmM with RdgC. Genome neighbourhood connections revealed several putative functionally linked genes, e.g. rlmH with genes coding for cell wall biosynthetic proteins and others. Comparative analysis of expression profiles (Gene Expression Omnibus) revealed two main associations, a group of genes expressed during fast growth and association of rrmJ with heat shock genes. This study might be used as a roadmap for further experimental verification of predicted functional interactions.
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Affiliation(s)
- Petr V Sergiev
- Lomonosov Moscow State University, Department of Chemistry and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow 119992, Russia.
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24
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Abstract
The web application PrimerPair at ecogene.org generates large sets of paired DNA sequences surrounding- all protein and RNA genes of Escherichia coli K-12. Many DNA fragments, which these primers amplify, can be used to implement a genome reengineering strategy using complementary in vitro cloning and in vivo recombineering. The integration of a primer design tool with a model organism database increases the level of quality control. Computer-assisted design of gene primer pairs relies upon having highly accurate genomic DNA sequence information that exactly matches the DNA of the cells being used in the laboratory to ensure predictable DNA hybridizations. It is equally crucial to have confidence that the predicted start codons define the locations of genes accurately. Annotations in the EcoGene database are queried by PrimerPair to eliminate pseudogenes, IS elements, and other problematic genes before the design process starts. These projects progressively familiarize users with the EcoGene content, scope, and application interfaces that are useful for genome reengineering projects. The first protocol leads to the design of a pair of primer sequences that were used to clone and express a single gene. The N-terminal protein sequence was experimentally verified and the protein was detected in the periplasm. This is followed by instructions to design PCR primer pairs for cloning gene fragments encoding 50 periplasmic proteins without their signal peptides. The design process begins with the user simply designating one pair of forward and reverse primer endpoint positions relative to all start and stop codon positions. The gene name, genomic coordinates, and primer DNA sequences are reported to the user. When making chromosomal deletions, the integrity of the provisional primer design is checked to see whether it will generate any unwanted double deletions with adjacent genes. The bad designs are recalculated and replacement primers are provided alongside the requested primers. A list of all genes with overlaps includes those expressed from the translational coupling motifs 5'-UGAUG-3' and 5'-AUGA-3'. Rigid alignments of the 893 ribosome binding sites (RBSs) linked to the AUG codons of this coupled subset are assessed for information content using WebLogo 3.0. These specialized logos are missing the G at the prominent information peak position normally seen in the rigid alignment of all genes. This novel GHOLE motif was apparently masked by the normal RBSs in two previously published rigid alignments. We propose a model constraining the distance between the ATG and the RBS, obviating- the need for a flexible linker model to reveal a Shine-Dalgarno-like sequence.
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Affiliation(s)
- Jindan Zhou
- Department of Electrical and Computer Engineering, University of Miami, Coral Gables, FL, USA
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Graille M, Figaro S, Kervestin S, Buckingham RH, Liger D, Heurgué-Hamard V. Methylation of class I translation termination factors: structural and functional aspects. Biochimie 2012; 94:1533-43. [PMID: 22266024 DOI: 10.1016/j.biochi.2012.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 01/07/2012] [Indexed: 12/23/2022]
Abstract
During protein synthesis, release of polypeptide from the ribosome occurs when an in frame termination codon is encountered. Contrary to sense codons, which are decoded by tRNAs, stop codons present in the A-site are recognized by proteins named class I release factors, leading to the release of newly synthesized proteins. Structures of these factors bound to termination ribosomal complexes have recently been obtained, and lead to a better understanding of stop codon recognition and its coordination with peptidyl-tRNA hydrolysis in bacteria. Release factors contain a universally conserved GGQ motif which interacts with the peptidyl-transferase centre to allow peptide release. The Gln side chain from this motif is methylated, a feature conserved from bacteria to man, suggesting an important biological role. However, methylation is catalysed by completely unrelated enzymes. The function of this motif and its post-translational modification will be discussed in the context of recent structural and functional studies.
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Affiliation(s)
- Marc Graille
- IBBMC, Université Paris-Sud 11, CNRS UMR8619, Orsay Cedex, F-91405, France.
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Wright JR, Keffer-Wilkes LC, Dobing SR, Kothe U. Pre-steady-state kinetic analysis of the three Escherichia coli pseudouridine synthases TruB, TruA, and RluA reveals uniformly slow catalysis. RNA (NEW YORK, N.Y.) 2011; 17:2074-84. [PMID: 21998096 PMCID: PMC3222121 DOI: 10.1261/rna.2905811] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 08/29/2011] [Indexed: 05/20/2023]
Abstract
Pseudouridine synthases catalyze formation of the most abundant modification of functional RNAs by site-specifically isomerizing uridines to pseudouridines. While the structure and substrate specificity of these enzymes have been studied in detail, the kinetic and the catalytic mechanism of pseudouridine synthases remain unknown. Here, the first pre-steady-state kinetic analysis of three Escherichia coli pseudouridine synthases is presented. A novel stopped-flow absorbance assay revealed that substrate tRNA binding by TruB takes place in two steps with an overall rate of 6 sec(-1). In order to observe catalysis of pseudouridine formation directly, the traditional tritium release assay was adapted for the quench-flow technique, allowing, for the first time, observation of a single round of pseudouridine formation. Thereby, the single-round rate constant of pseudouridylation (k(Ψ)) by TruB was determined to be 0.5 sec(-1). This rate constant is similar to the k(cat) obtained under multiple-turnover conditions in steady-state experiments, indicating that catalysis is the rate-limiting step for TruB. In order to investigate if pseudouridine synthases are characterized by slow catalysis in general, the rapid kinetic quench-flow analysis was also performed with two other E. coli enzymes, RluA and TruA, which displayed rate constants of pseudouridine formation of 0.7 and 0.35 sec(-1), respectively. Hence, uniformly slow catalysis might be a general feature of pseudouridine synthases that share a conserved catalytic domain and supposedly use the same catalytic mechanism.
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Affiliation(s)
- Jaden R. Wright
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Laura C. Keffer-Wilkes
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Selina R. Dobing
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Ute Kothe
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
- Corresponding author.E-mail .
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Sumita M, Jiang J, SantaLucia J, Chow CS. Comparison of solution conformations and stabilities of modified helix 69 rRNA analogs from bacteria and human. Biopolymers 2011; 97:94-106. [PMID: 21858779 DOI: 10.1002/bip.21706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/31/2011] [Indexed: 12/20/2022]
Abstract
The helix 69 (H69) region of the large subunit (28S) ribosomal RNA (rRNA) of Homo sapiens contains five pseudouridine (Ψ) residues out of 19 total nucleotides, three of which are highly conserved. In this study, the effects of this abundant modified nucleotide on the structure and stability of H69 were compared with those of uridine in double-stranded (stem) regions. These results were compared with previous hairpin (stem plus single-stranded loop) studies to understand the contributions of the loop sequences to H69 structure and stability. The role of a loop nucleotide substitution from an A in bacteria (position 1918 in Escherichia coli 23S rRNA) to a G in eukaryotes (position 3734 in H. sapiens 28S rRNA) was examined. Thermodynamic parameters for the duplex RNAs were obtained through UV melting studies, and differences in the modified and unmodified RNA structures were examined by circular dichroism spectroscopy. The overall folded structure of human H69 appears to be similar to the bacterial RNA, consistent with the idea that ribosome structure and function are highly conserved; however, our results reveal subtle differences in structure and stability between the bacterial and human H69 RNAs in both the stem and loop regions. These findings may be significant with respect to H69 as a potential drug target site.
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Affiliation(s)
- Minako Sumita
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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Small RNAs endow a transcriptional activator with essential repressor functions for single-tier control of a global stress regulon. Proc Natl Acad Sci U S A 2011; 108:12875-80. [PMID: 21768388 DOI: 10.1073/pnas.1109379108] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Escherichia coli σ(E) envelope stress response monitors and repairs the outer membrane, a function central to the life of Gram-negative bacteria. The σ(E) stress response was characterized as a single-tier activation network comprised of ~100 genes, including the MicA and RybB noncoding sRNAs. These highly expressed sRNAs were thought to carry out the specialized function of halting de novo synthesis of several abundant porins when envelope homeostasis was perturbed. Using a systematic target profiling and validation approach we discovered that MicA and RybB are each global mRNA repressors of both distinct and shared targets, and that the two sRNAs constitute a posttranscriptional repression arm whose regulatory scope rivals that of the protein-based σ(E) activation arm. Intriguingly, porin mRNAs constitute only ~1/3 of all targets and new nonporin targets predict roles for MicA and RybB in crosstalk with other regulatory responses. This work also provides an example of evolutionarily unrelated sRNAs that are coinduced and bind the same targets, but at different sites. Our finding that expression of either MicA or RybB sRNA protects the cell from the loss of viability experienced when σ(E) activity is inadequate illustrates the importance of the posttranscriptional repression arm of the response. σ(E) is a paradigm of a single-tier stress response with a clear division of labor in which highly expressed noncoding RNAs (MicA, RybB) endow a transcriptional factor intrinsically restricted to gene activation (σ(E)) with the opposite repressor function.
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Ortiz-Meoz RF, Green R. Helix 69 is key for uniformity during substrate selection on the ribosome. J Biol Chem 2011; 286:25604-10. [PMID: 21622559 DOI: 10.1074/jbc.m111.256255] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Structural studies of ribosome complexes with bound tRNAs and release factors show considerable contacts between these factors and helix 69 (H69) of 23 S rRNA. Although biochemical and genetic studies have provided some general insights into the role of H69 in tRNA and RF selection, a detailed understanding of these contributions remains elusive. Here, we present a pre- steady-state kinetic analysis establishing that two distinct regions of H69 make critical contributions to substrate selection. The loop of H69 (A1913) forms contacts necessary for the efficient accommodation of a subset of natural tRNA species, whereas the base of the stem (G1922) is specifically critical for UGA codon recognition by the class 1 release factor RF2. These data define a broad and critical role for this centrally located intersubunit helix (H69) in accurate and efficient substrate recognition by the ribosome.
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Affiliation(s)
- Rodrigo F Ortiz-Meoz
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Pseudouridylation of 23S rRNA helix 69 promotes peptide release by release factor RF2 but not by release factor RF1. Biochimie 2011; 93:834-44. [PMID: 21281690 DOI: 10.1016/j.biochi.2010.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 12/30/2010] [Indexed: 11/22/2022]
Abstract
Pseudouridine [Ψ] is a frequent base modification in the ribosomal RNA [rRNA] and may be involved in the modulation of the conformational flexibility of rRNA helix-loop structures during protein synthesis. Helix 69 of 23S rRNA contains pseudouridines at the positions 1911, 1915 and 1917 which are formed by the helix 69-specific synthase RluD. The growth defect caused by the lack of RluD can be rescued by mutations in class I release factor RF2, indicating a role for helix 69 pseudouridines in translation termination. We investigated the role of helix 69 pseudouridines in peptide release by release factors RF1 and RF2 in an in vitro system consisting of purified components of the Escherichia coli translation apparatus. Lack of all three pseudouridines in helix 69 compromised the activity of RF2 about 3-fold but did not significantly affect the activity of RF1. Reintroduction of pseudouridines into helix 69 by RluD-treatment restored the activity of RF2 in peptide release. A Ψ-to-C substitution at the 1917 position caused an increase in the dissociation rate of RF1 and RF2 from the postrelease ribosome. Our results indicate that the presence of all three pseudouridines in helix 69 stimulates peptide release by RF2 but has little effect on the activity of RF1. The interactions around the pseudouridine at the 1917 position appear to be most critical for a proper interaction of helix 69 with release factors.
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O'Connor M, Gregory ST. Inactivation of the RluD pseudouridine synthase has minimal effects on growth and ribosome function in wild-type Escherichia coli and Salmonella enterica. J Bacteriol 2011; 193:154-62. [PMID: 21037010 PMCID: PMC3019933 DOI: 10.1128/jb.00970-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 10/18/2010] [Indexed: 11/20/2022] Open
Abstract
The Escherichia coli rluD gene encodes a pseudouridine synthase responsible for the pseudouridine (Ψ) modifications at positions 1911, 1915, and 1917 in helix 69 of 23S rRNA. It has been reported that deletion of rluD in K-12 strains of E. coli is associated with extremely slow growth, increased readthrough of stop codons, and defects in 50S ribosomal subunit assembly and 30S-50S subunit association. Suppressor mutations in the prfB and prfC genes encoding release factor 2 (RF2) and RF3 that restore the wild type-growth rate and also correct the ribosomal defects have now been isolated. These suppressors link helix 69 Ψ residues with the termination phase of protein synthesis. However, further genetic analysis reported here also reveals that the slow growth and other defects associated with inactivation of rluD in E. coli K-12 strains are due to a defective RF2 protein, with a threonine at position 246, which is present in all K-12 strains. This is in contrast to the more typical alanine found at this position in most bacterial RF2s, including those of other E. coli strains. Inactivation of rluD in E. coli strains containing the prfB allele from E. coli B or in Salmonella enterica, both carrying an RF2 with Ala246, has negligible effects on growth, termination, or ribosome function. The results indicate that, in contrast to those in wild bacteria, termination functions in E. coli K-12 strains carrying a partially defective RF2 protein are especially susceptible to perturbation of ribosome-RF interactions, such as that caused by loss of h69 Ψ modifications.
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Affiliation(s)
- Michael O'Connor
- School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Rd, Kansas City, Missouri 64110, USA.
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Schaub RE, Hayes CS. Deletion of the RluD pseudouridine synthase promotes SsrA peptide tagging of ribosomal protein S7. Mol Microbiol 2010; 79:331-41. [PMID: 21219455 DOI: 10.1111/j.1365-2958.2010.07467.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RluD catalyses formation of three pseudouridine residues within helix 69 of the 50S ribosome subunit. Helix 69 makes important contacts with the decoding centre on the 30S subunit and deletion of rluD was recently shown to interfere with translation termination in Escherichia coli. Here, we show that deletion of rluD increases tmRNA activity on ribosomes undergoing release factor 2 (RF2)-mediated termination at UGA stop codons. Strikingly, tmRNA-mediated SsrA peptide tagging of two proteins, ribosomal protein S7 and LacI, was dramatically increased in ΔrluD cells. S7 tagging was due to a unique C-terminal peptide extension found in E. coli K-12 strains. Introduction of the rpsG gene (encoding S7) from an E. coli B strain abrogated S7 tagging in the ΔrluD background, and partially complemented the mutant's slow-growth phenotype. Additionally, exchange of the K-12 prfB gene (encoding RF2) with the B strain allele greatly reduced tagging in ΔrluD cells. In contrast to E. coli K-12 cells, deletion of rluD in an E. coli B strain resulted in no growth phenotype. These findings indicate that the originally observed rluD phenotypes result from synthetic interactions with rpsG and prfB alleles found within E. coli K-12 strains.
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Affiliation(s)
- Ryan E Schaub
- Department of Molecular, Cellular and Developmental Biology Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA
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Abstract
In this issue of Molecular Microbiology, Schaub and Hayes report that, compared with other enterobacteria, Escherichia coli K12 carries two mutations - one in the prfB gene encoding the release factor RF2, and the other in the rpsG gene encoding r-protein S7 - that together concur in compromising translation termination at the essential rpsG gene. As a consequence, the growth of E. coli K12 is very sensitive to a further mutation (rluD(-) ) that depresses RF2 activity, whereas the growth of its close relative, E. coli B, is not. We tentatively discuss how the K12-specific mutations in RF2 and S7 might have occurred and why inefficient translation termination at rpsG inhibits growth. The work of Schaub and Hayes illustrates the fact that, due probably to its long history in the laboratory, E. coli K12 has accumulated mutations that sometimes limit its value as a model for studying basic steps in prokaryotic gene expression.
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Affiliation(s)
- Marc Dreyfus
- CNRS UPR9073 associated with University Paris VII, Institut de Biologie Physico-chimique, 13 rue Pierre et Marie Curie 75005 Paris, France.
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Ero R, Leppik M, Liiv A, Remme J. Specificity and kinetics of 23S rRNA modification enzymes RlmH and RluD. RNA (NEW YORK, N.Y.) 2010; 16:2075-84. [PMID: 20817755 PMCID: PMC2957048 DOI: 10.1261/rna.2234310] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 07/30/2010] [Indexed: 05/29/2023]
Abstract
Along the ribosome assembly pathway, various ribosomal RNA processing and modification reactions take place. Stem-loop 69 in the large subunit of Escherichia coli ribosomes plays a substantial role in ribosome functioning. It contains three highly conserved pseudouridines synthesized by pseudouridine synthase RluD. One of the pseudouridines is further methylated by RlmH. In this paper we show that RlmH has unique substrate specificity among rRNA modification enzymes. It preferentially methylates pseudouridine and less efficiently uridine. Furthermore, RlmH is the only known modification enzyme that is specific to 70S ribosomes. Kinetic parameters determined for RlmH are the following: The apparent K(M) for substrate 70S ribosomes is 0.51 ± 0.06 μM, and for cofactor S-adenosyl-L-methionine 27 ± 3 μM; the k(cat) values are 4.95 ± 1.10 min⁻¹ and 6.4 ± 1.3 min⁻¹, respectively. Knowledge of the substrate specificity and the kinetic parameters of RlmH made it possible to determine the kinetic parameters for RluD as well. The K(M) value for substrate 50S subunits is 0.98 ± 0.18 μM and the k(cat) value is 1.97 ± 0.46 min⁻¹. RluD is the first rRNA pseudouridine synthase to be kinetically characterized. The determined rates of RluD- and RlmH-directed modifications of 23S rRNA are compatible with the rate of 50S assembly in vivo. The fact that RlmH requires 30S subunits demonstrates the dependence of 50S subunit maturation on the simultaneous presence of 30S subunits.
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Affiliation(s)
- Rya Ero
- Department of Molecular Biology, Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia
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35
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Baudin-Baillieu A, Fabret C, Liang XH, Piekna-Przybylska D, Fournier MJ, Rousset JP. Nucleotide modifications in three functionally important regions of the Saccharomyces cerevisiae ribosome affect translation accuracy. Nucleic Acids Res 2010; 37:7665-77. [PMID: 19820108 PMCID: PMC2794176 DOI: 10.1093/nar/gkp816] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Important regions of rRNA are rich in nucleotide modifications that can have strong effects on ribosome biogenesis and translation efficiency. Here, we examine the influence of pseudouridylation and 2′-O-methylation on translation accuracy in yeast, by deleting the corresponding guide snoRNAs. The regions analyzed were: the decoding centre (eight modifications), and two intersubunit bridge domains—the A-site finger and Helix 69 (six and five modifications). Results show that a number of modifications influence accuracy with effects ranging from 0.3- to 2.4-fold of wild-type activity. Blocking subsets of modifications, especially from the decoding region, impairs stop codon termination and reading frame maintenance. Unexpectedly, several Helix 69 mutants possess ribosomes with increased fidelity. Consistent with strong positional and synergistic effects is the finding that single deletions can have a more pronounced phenotype than multiple deficiencies in the same region. Altogether, the results demonstrate that rRNA modifications have significant roles in translation accuracy.
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Helix 69 in 23S rRNA modulates decoding by wild type and suppressor tRNAs. Mol Genet Genomics 2009; 282:371-80. [PMID: 19603183 DOI: 10.1007/s00438-009-0470-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 06/27/2009] [Indexed: 10/20/2022]
Abstract
Helix 69 of 23S rRNA forms one of the major inter-subunit bridges of the 70S ribosome and interacts with A- and P-site tRNAs and translation factors. Despite the proximity of h69 to the decoding center and tRNAs, the contribution of h69 to the tRNA selection process is unclear: previous genetic analyses have shown that h69 mutations increase frameshifting and readthrough of stop codons. However, a complete deletion of h69 does not affect the selection of cognate tRNAs in vitro. To address these discrepancies, the in vivo effects of a range of single- and multi-base h69 mutations in Escherichia coli 23S rRNA on various translation errors have been determined. While a majority of the h69 mutations examined here affected readthrough of stop codons and frameshifting, the DeltaA1916 single base deletion mutation uniquely influenced missense decoding. Different h69 mutants had either increased or decreased levels of stop codon readthrough. The h69 mutations that decreased UGA readthrough also decreased UGA reading by a mutant, near-cognate tRNA(Trp) carrying a G24A substitution in the D arm, but had far less effect on UGA reading by a suppressor tRNA with a complementary anticodon. These results suggest that h69 interactions with release factors contribute significantly to termination efficiency and that interaction with the D arm of A-site tRNA is important for discrimination between cognate and near-cognate tRNAs.
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Duan J, Li L, Lu J, Wang W, Ye K. Structural mechanism of substrate RNA recruitment in H/ACA RNA-guided pseudouridine synthase. Mol Cell 2009; 34:427-39. [PMID: 19481523 DOI: 10.1016/j.molcel.2009.05.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 04/11/2009] [Accepted: 05/07/2009] [Indexed: 11/28/2022]
Abstract
H/ACA RNAs form ribonucleoprotein complex (RNP) with proteins Cbf5, Nop10, L7Ae, and Gar1 and guide site-specific conversion of uridine into pseudouridine in cellular RNAs. The crystal structures of H/ACA RNP with substrate bound at the active site cleft reveal that the substrate is recruited through sequence-specific pairing with guide RNA and essential protein contacts. Substrate binding leads to a reorganization of a preset pseudouridylation pocket and an adaptive movement of the PUA domain and the lower stem of the H/ACA RNA. Moreover, a thumb loop flips from the Gar1-bound state in the substrate-free RNP structure to tightly associate with the substrate. Mutagenesis and enzyme kinetics analysis suggest a critical role of Gar1 and the thumb in substrate turnover, particularly in product release. Comparison with tRNA Psi55 synthase TruB reveals the structural conservation and adaptation between an RNA-guided and stand-alone pseudouridine synthase and provides insight into the guide-independent activity of Cbf5.
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Affiliation(s)
- Jingqi Duan
- College of Life Sciences, Peking University, Beijing, China
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Seshadri A, Dubey B, Weber MHW, Varshney U. Impact of rRNA methylations on ribosome recycling and fidelity of initiation inEscherichia coli. Mol Microbiol 2009; 72:795-808. [DOI: 10.1111/j.1365-2958.2009.06685.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Connolly K, Culver G. Deconstructing ribosome construction. Trends Biochem Sci 2009; 34:256-63. [PMID: 19376708 DOI: 10.1016/j.tibs.2009.01.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 12/30/2022]
Abstract
The ribosome is an essential ribonucleoprotein enzyme, and its biogenesis is a fundamental process in all living cells. Recent X-ray crystal structures of the bacterial ribosome and new technologies have allowed a greater interrogation of in vitro ribosome assembly; however, substantially less is known about ribosome biogenesis in vivo. Ongoing investigations are focused on elucidating the cellular processes that facilitate biogenesis of the ribosomal subunits, and many extraribosomal factors, including modification enzymes, remodeling enzymes and GTPases, are being uncovered. Moreover, specific roles for ribosome biogenesis factors in subunit maturation are now being elaborated. Ultimately, such studies will reveal a more complete understanding of processes at work in in vivo ribosome biogenesis.
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Affiliation(s)
- Keith Connolly
- Departments of Biology and of Biochemistry and Biophysics, University of Rochester, Rochester, NY 14627, USA
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Alian A, DeGiovanni A, Griner SL, Finer-Moore JS, Stroud RM. Crystal structure of an RluF-RNA complex: a base-pair rearrangement is the key to selectivity of RluF for U2604 of the ribosome. J Mol Biol 2009; 388:785-800. [PMID: 19298824 DOI: 10.1016/j.jmb.2009.03.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/18/2009] [Accepted: 03/11/2009] [Indexed: 12/25/2022]
Abstract
Escherichia coli pseudouridine synthase RluF is dedicated to modifying U2604 in a stem-loop of 23S RNA, while a homologue, RluB, modifies the adjacent base, U2605. Both uridines are in the same RNA stem, separated by approximately 4 A. The 3.0 A X-ray crystal structure of RluF bound to the isolated stem-loop, in which U2604 is substituted by 5-fluorouridine to prevent catalytic turnover, shows RluF distinguishes closely spaced bases in similar environments by a selectivity mechanism based on a frameshift in base pairing. The RNA stem-loop is bound to a conserved binding groove in the catalytic domain. A base from a bulge in the stem, A2602, has folded into the stem, forcing one strand of the RNA stem to translate by one position and thus positioning U2604 to flip into the active site. RluF does not modify U2604 in mutant stem-loops that lack the A2602 bulge and shows dramatically higher activity for a stem-loop with a mutation designed to facilitate A2602 refolding into the stem with concomitant RNA strand translation. Residues whose side chains contact rearranged bases in the bound stem-loop, while conserved among RluFs, are not conserved between RluFs and RluBs, suggesting that RluB does not bind to the rearranged stem loop.
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Affiliation(s)
- Akram Alian
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2517, USA
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Kipper K, Hetényi C, Sild S, Remme J, Liiv A. Ribosomal Intersubunit Bridge B2a Is Involved in Factor-Dependent Translation Initiation and Translational Processivity. J Mol Biol 2009; 385:405-22. [DOI: 10.1016/j.jmb.2008.10.065] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 10/14/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
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Weixlbaumer A, Jin H, Neubauer C, Voorhees RM, Petry S, Kelley AC, Ramakrishnan V. Insights into translational termination from the structure of RF2 bound to the ribosome. Science 2008; 322:953-6. [PMID: 18988853 DOI: 10.1126/science.1164840] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The termination of protein synthesis occurs through the specific recognition of a stop codon in the A site of the ribosome by a release factor (RF), which then catalyzes the hydrolysis of the nascent protein chain from the P-site transfer RNA. Here we present, at a resolution of 3.5 angstroms, the crystal structure of RF2 in complex with its cognate UGA stop codon in the 70S ribosome. The structure provides insight into how RF2 specifically recognizes the stop codon; it also suggests a model for the role of a universally conserved GGQ motif in the catalysis of peptide release.
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Affiliation(s)
- Albert Weixlbaumer
- Medical Research Council (MRC) Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
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Grosjean H, Gaspin C, Marck C, Decatur WA, de Crécy-Lagard V. RNomics and Modomics in the halophilic archaea Haloferax volcanii: identification of RNA modification genes. BMC Genomics 2008; 9:470. [PMID: 18844986 PMCID: PMC2584109 DOI: 10.1186/1471-2164-9-470] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 10/09/2008] [Indexed: 12/14/2022] Open
Abstract
Background Naturally occurring RNAs contain numerous enzymatically altered nucleosides. Differences in RNA populations (RNomics) and pattern of RNA modifications (Modomics) depends on the organism analyzed and are two of the criteria that distinguish the three kingdoms of life. If the genomic sequences of the RNA molecules can be derived from whole genome sequence information, the modification profile cannot and requires or direct sequencing of the RNAs or predictive methods base on the presence or absence of the modifications genes. Results By employing a comparative genomics approach, we predicted almost all of the genes coding for the t+rRNA modification enzymes in the mesophilic moderate halophile Haloferax volcanii. These encode both guide RNAs and enzymes. Some are orthologous to previously identified genes in Archaea, Bacteria or in Saccharomyces cerevisiae, but several are original predictions. Conclusion The number of modifications in t+rRNAs in the halophilic archaeon is surprisingly low when compared with other Archaea or Bacteria, particularly the hyperthermophilic organisms. This may result from the specific lifestyle of halophiles that require high intracellular salt concentration for survival. This salt content could allow RNA to maintain its functional structural integrity with fewer modifications. We predict that the few modifications present must be particularly important for decoding, accuracy of translation or are modifications that cannot be functionally replaced by the electrostatic interactions provided by the surrounding salt-ions. This analysis also guides future experimental validation work aiming to complete the understanding of the function of RNA modifications in Archaeal translation.
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Affiliation(s)
- Henri Grosjean
- Department of Microbiology, University of Florida, Gainsville, FL 32611, Florida, USA.
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Purta E, Kaminska KH, Kasprzak JM, Bujnicki JM, Douthwaite S. YbeA is the m3Psi methyltransferase RlmH that targets nucleotide 1915 in 23S rRNA. RNA (NEW YORK, N.Y.) 2008; 14:2234-44. [PMID: 18755835 PMCID: PMC2553730 DOI: 10.1261/rna.1198108] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 07/09/2008] [Indexed: 05/26/2023]
Abstract
Pseudouridines in the stable RNAs of Bacteria are seldom subjected to further modification. There are 11 pseudouridine (Psi) sites in Escherichia coli rRNA, and further modification is found only at Psi1915 in 23S rRNA, where the N-3 position of the base becomes methylated. Here, we report the identity of the E. coli methyltransferase that specifically catalyzes methyl group addition to form m(3)Psi1915. Analyses of E. coli rRNAs using MALDI mass spectrometry showed that inactivation of the ybeA gene leads to loss of methylation at nucleotide Psi1915. Methylation is restored by complementing the knockout strain with a plasmid-encoded copy of ybeA. Homologs of the ybeA gene, and thus presumably the ensuing methylation at nucleotide m(3)Psi1915, are present in most bacterial lineages but are essentially absent in the Archaea and Eukaryota. Loss of ybeA function in E. coli causes a slight slowing of the growth rate. Phylogenetically, ybeA and its homologs are grouped with other putative S-adenosylmethionine-dependent, SPOUT methyltransferase genes in the Cluster of Orthologous Genes COG1576; ybeA is the first member to be functionally characterized. The YbeA methyltransferase is active as a homodimer and docks comfortably into the ribosomal A site without encroaching into the P site. YbeA makes extensive interface contacts with both the 30S and 50S subunits to align its active site cofactor adjacent to nucleotide Psi1915. Methylation by YbeA (redesignated RlmH for rRNA large subunit methyltransferase H) possibly functions as a stamp of approval signifying that the 50S subunit has engaged in translational initiation.
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Affiliation(s)
- Elzbieta Purta
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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Ero R, Peil L, Liiv A, Remme J. Identification of pseudouridine methyltransferase in Escherichia coli. RNA (NEW YORK, N.Y.) 2008; 14:2223-33. [PMID: 18755836 PMCID: PMC2553739 DOI: 10.1261/rna.1186608] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 07/09/2008] [Indexed: 05/26/2023]
Abstract
In ribosomal RNA, modified nucleosides are found in functionally important regions, but their function is obscure. Stem-loop 69 of Escherichia coli 23S rRNA contains three modified nucleosides: pseudouridines at positions 1911 and 1917, and N3 methyl-pseudouridine (m(3)Psi) at position 1915. The gene for pseudouridine methyltransferase was previously not known. We identified E. coli protein YbeA as the methyltransferase methylating Psi1915 in 23S rRNA. The E. coli ybeA gene deletion strain lacks the N3 methylation at position 1915 of 23S rRNA as revealed by primer extension and nucleoside analysis by HPLC. Methylation at position 1915 is restored in the ybeA deletion strain when recombinant YbeA protein is expressed from a plasmid. In addition, we show that purified YbeA protein is able to methylate pseudouridine in vitro using 70S ribosomes but not 50S subunits from the ybeA deletion strain as substrate. Pseudouridine is the preferred substrate as revealed by the inability of YbeA to methylate uridine at position 1915. This shows that YbeA is acting at the final stage during ribosome assembly, probably during translation initiation. Hereby, we propose to rename the YbeA protein to RlmH according to uniform nomenclature of RNA methyltransferases. RlmH belongs to the SPOUT superfamily of methyltransferases. RlmH was found to be well conserved in bacteria, and the gene is present in plant and in several archaeal genomes. RlmH is the first pseudouridine specific methyltransferase identified so far and is likely to be the only one existing in bacteria, as m(3)Psi1915 is the only methylated pseudouridine in bacteria described to date.
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Affiliation(s)
- Rya Ero
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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Suppression of DeltabipA phenotypes in Escherichia coli by abolishment of pseudouridylation at specific sites on the 23S rRNA. J Bacteriol 2008; 190:7675-83. [PMID: 18820021 DOI: 10.1128/jb.00835-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The BipA protein of Escherichia coli has intriguing similarities to the elongation factor subfamily of GTPases, including EF-Tu, EF-G, and LepA. In addition, phenotypes of a bipA deletion mutant suggest that BipA is involved in regulation of a variety of pathways. These two points have led to speculation that BipA may be a novel regulatory protein that affects efficient translation of target genes through direct interaction with the ribosome. We isolated and characterized suppressors of the cold-sensitive growth phenotype exhibited by DeltabipA strains and identified insertion mutations in rluC. The rluC gene encodes a pseudouridine synthase responsible for pseudouridine modification of 23S rRNA at three sites, all located near the peptidyl transferase center. Deletion of rluC not only suppressed cold sensitivity but also alleviated the decrease in capsule synthesis exhibited by bipA mutants, suggesting that the phenotypic effects of BipA are manifested through an effect on the ribosome. The suppressor effect is specific to rluC, as deletion of other rlu genes did not relieve cold sensitivity, and further, more than a single pseudouridine residue is involved, as alteration of single residues did not produce suppressors. These results are consistent with a role for BipA in either the structure or the function of the ribosome and imply that wild-type ribosomes are dependent on BipA for efficient expression of target mRNAs and that the lack of pseudouridylation at these three sites renders the ribosomes BipA independent.
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Mutations in conserved helix 69 of 23S rRNA of Thermus thermophilus that affect capreomycin resistance but not posttranscriptional modifications. J Bacteriol 2008; 190:7754-61. [PMID: 18805973 DOI: 10.1128/jb.00984-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Translocation during the elongation phase of protein synthesis involves the relative movement of the 30S and 50S ribosomal subunits. This movement is the target of tuberactinomycin antibiotics. Here, we describe the isolation and characterization of mutants of Thermus thermophilus selected for resistance to the tuberactinomycin antibiotic capreomycin. Two base substitutions, A1913U and mU1915G, and a single base deletion, DeltamU1915, were identified in helix 69 of 23S rRNA, a structural element that forms part of an interribosomal subunit bridge with the decoding center of 16S rRNA, the site of previously reported capreomycin resistance base substitutions. Capreomycin resistance in other bacteria has been shown to result from inactivation of the TlyA methyltransferase which 2'-O methylates C1920 of 23S rRNA. Inactivation of the tlyA gene in T. thermophilus does not affect its sensitivity to capreomycin. Finally, none of the mutations in helix 69 interferes with methylation at C1920 or with pseudouridylation at positions 1911 and 1917. We conclude that the resistance phenotype is a consequence of structural changes introduced by the mutations.
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Abeysirigunawardena SC, Chow CS. pH-dependent structural changes of helix 69 from Escherichia coli 23S ribosomal RNA. RNA (NEW YORK, N.Y.) 2008; 14:782-92. [PMID: 18268024 PMCID: PMC2271367 DOI: 10.1261/rna.779908] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Helix 69 in 23S rRNA is a region in the ribosome that participates in a considerable number of RNA-RNA and RNA-protein interactions. Conformational flexibility is essential for such a region to interact and accommodate protein factors at different stages of protein biosynthesis. In this study, pH-dependent structural and stability changes were observed for helix 69 through a variety of spectroscopic techniques, such as circular dichroism spectroscopy, UV melting, and nuclear magnetic resonance spectroscopy. In Escherichia coli 23S rRNA, helix 69 contains pseudouridine residues at positions 1911, 1915, and 1917. The presence of these pseudouridines was found to be essential for the pH-induced conformational changes. Some of the pH-dependent changes appear to be localized to the loop region of helix 69, emphasizing the importance of the highly conserved nature of residues in this region.
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MESH Headings
- Base Sequence
- Circular Dichroism
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Hydrogen-Ion Concentration
- Models, Molecular
- Nucleic Acid Conformation
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal, 23S/chemistry
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/metabolism
- Thermodynamics
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Muller S, Leclerc F, Behm-Ansmant I, Fourmann JB, Charpentier B, Branlant C. Combined in silico and experimental identification of the Pyrococcus abyssi H/ACA sRNAs and their target sites in ribosomal RNAs. Nucleic Acids Res 2008; 36:2459-75. [PMID: 18304947 PMCID: PMC2377435 DOI: 10.1093/nar/gkn077] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
How far do H/ACA sRNPs contribute to rRNA pseudouridylation in Archaea was still an open question. Hence here, by computational search in three Pyrococcus genomes, we identified seven H/ACA sRNAs and predicted their target sites in rRNAs. In parallel, we experimentally identified 17 Ψ residues in P. abyssi rRNAs. By in vitro reconstitution of H/ACA sRNPs, we assigned 15 out of the 17 Ψ residues to the 7 identified H/ACA sRNAs: one H/ACA motif can guide up to three distinct pseudouridylations. Interestingly, by using a 23S rRNA fragment as the substrate, one of the two remaining Ψ residues could be formed in vitro by the aCBF5/aNOP10/aGAR1 complex without guide sRNA. Our results shed light on structural constraints in archaeal H/ACA sRNPs: the length of helix H2 is of 5 or 6 bps, the distance between the ANA motif and the targeted U residue is of 14 or 15 nts, and the stability of the interaction formed by the substrate rRNA and the 3′-guide sequence is more important than that formed with the 5′-guide sequence. Surprisingly, we showed that a sRNA–rRNA interaction with the targeted uridine in a single-stranded 5′-UNN-3′ trinucleotide instead of the canonical 5′-UN-3′ dinucleotide is functional.
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Affiliation(s)
- Sébastien Muller
- Laboratoire de Maturation des ARN et Enzymologie Moléculaire, UMR 7567 CNRS-UHP, Nancy Université, Faculté des Sciences et Techniques, 54506 Vandoeuvre-lès-Nancy, France
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