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Abstract
An RNA World that predated the modern world of polypeptide and polynucleotide is one of the most widely accepted models in origin of life research. In this model, the translation system shepherded the RNA World into the extant biology of DNA, RNA, and protein. Here, we examine the RNA World Hypothesis in the context of increasingly detailed information available about the origins, evolution, functions, and mechanisms of the translation system. We conclude that the translation system presents critical challenges to RNA World Hypotheses. Firstly, a timeline of the RNA World is problematic when the ribosome is incorporated. The mechanism of peptidyl transfer of the ribosome appears distinct from evolved enzymes, signaling origins in a chemical rather than biological milieu. Secondly, we have no evidence that the basic biochemical toolset of life is subject to substantive change by Darwinian evolution, as required for the transition from the RNA world to extant biology. Thirdly, we do not see specific evidence for biological takeover of ribozyme function by protein enzymes. Finally, we can find no basis for preservation of the ribosome as ribozyme or the universality of translation, if it were the case that other information transducing ribozymes, such as ribozyme polymerases, were replaced by protein analogs and erased from the phylogenetic record. We suggest that an updated model of the RNA World should address the current state of knowledge of the translation system.
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352
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Yanshina DD, Bulygin KN, Malygin AA, Karpova GG. Hydroxylated histidine of human ribosomal protein uL2 is involved in maintaining the local structure of 28S rRNA in the ribosomal peptidyl transferase center. FEBS J 2015; 282:1554-66. [PMID: 25702831 DOI: 10.1111/febs.13241] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 12/13/2022]
Abstract
Protein uL2 is essential for the catalytic activity of the ribosome and has a conserved shape in ribosomes from all domains of life. However, the sequence of its unstructured C-terminal loop apex that contacts the conserved 23S/28S rRNA helix (H) 93 near the ribosomal peptidyl transferase center differs in bacteria, archaea and eukaryotes. Eukaryote-specific residue His216 located in this loop in mammalian uL2 is hydroxylated in ribosomes. We used a set of chemical probes to explore the structure of an RNA that mimicked a segment of 28S rRNA domain V containing part of the uL2 binding site including H93, complexed with either natural (hydroxylated) or recombinant (unmodified) human uL2. It was found that both protein forms engage H93 during binding, but only natural uL2 (uL2n) protects it from hydroxyl radicals. The association of uL2n with RNA leads to changes in its structure at U4532 adjacent to the universally conserved U4531 (U2585, Escherichia coli numbering) involved in peptidyl transferase center formation, and at the universally conserved C4447 (2501) located in the ribosome near A4397 (2451) and C3909 (2063) belonging to the peptidyl transferase center. As a result, both nucleotides become strongly exposed to hydroxyl radicals. Our data argue that the hydroxyl group at His216 in the C-terminal loop apex of mammalian uL2 contributes to stabilization of a protein conformation that is favorable for binding to H93 of 28S rRNA and that this binding induces structural rearrangement in the regions close to the peptidyl transferase center in the mature ribosome.
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Affiliation(s)
- Darya D Yanshina
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk, Russia
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353
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Panecka J, Šponer J, Trylska J. Conformational dynamics of bacterial and human cytoplasmic models of the ribosomal A-site. Biochimie 2015; 112:96-110. [PMID: 25748164 DOI: 10.1016/j.biochi.2015.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 02/23/2015] [Indexed: 01/12/2023]
Abstract
The aminoacyl-tRNA binding site (A-site) is located in helix 44 of small ribosomal subunit. The mobile adenines 1492 and 1493 (Escherichia coli numbering), forming the A-site bulge, act as a functional switch that ensures mRNA decoding accuracy. Structural data on the oligonucleotide models mimicking the ribosomal A-site with sequences corresponding to bacterial and human cytoplasmic sites confirm that this RNA motif forms also without the ribosome context. We performed all-atom molecular dynamics simulations of these crystallographic A-site models to compare their conformational properties. We found that the human A-site bulge is more internally flexible than the bacterial one and has different base pairing preferences, which result in the overall different shapes of these bulges and cation density distributions. Also, in the human A-site model we observed repetitive destacking of A1492, while A1493 was more stably paired than in the bacterial variant. Based on the dynamics of the A-sites we suggest why aminoglycoside antibiotics, which target the bacterial A-site, have lower binding affinities and anti-translational activities toward the human variant.
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Affiliation(s)
- Joanna Panecka
- Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Żwirki i Wigury 93, 02-089 Warsaw, Poland; Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Jiří Šponer
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic; Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic.
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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354
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Marcel V, Catez F, Diaz JJ. p53, a translational regulator: contribution to its tumour-suppressor activity. Oncogene 2015; 34:5513-23. [DOI: 10.1038/onc.2015.25] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/08/2015] [Accepted: 01/12/2015] [Indexed: 12/14/2022]
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355
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Bhat P, Shwetha S, Sharma DK, Joseph AP, Srinivasan N, Das S. The beta hairpin structure within ribosomal protein S5 mediates interplay between domains II and IV and regulates HCV IRES function. Nucleic Acids Res 2015; 43:2888-901. [PMID: 25712089 PMCID: PMC4357715 DOI: 10.1093/nar/gkv110] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Translation initiation in Hepatitis C Virus (HCV) is mediated by Internal Ribosome Entry Site (IRES), which is independent of cap-structure and uses a limited number of canonical initiation factors. During translation initiation IRES–40S complex formation depends on high affinity interaction of IRES with ribosomal proteins. Earlier, it has been shown that ribosomal protein S5 (RPS5) interacts with HCV IRES. Here, we have extensively characterized the HCV IRES–RPS5 interaction and demonstrated its role in IRES function. Computational modelling and RNA–protein interaction studies demonstrated that the beta hairpin structure within RPS5 is critically required for the binding with domains II and IV. Mutations disrupting IRES–RPS5 interaction drastically reduced the 80S complex formation and the corresponding IRES activity. Computational analysis and UV cross-linking experiments using various IRES-mutants revealed interplay between domains II and IV mediated by RPS5. In addition, present study demonstrated that RPS5 interaction is unique to HCV IRES and is not involved in 40S–3′ UTR interaction. Further, partial silencing of RPS5 resulted in preferential inhibition of HCV RNA translation. However, global translation was marginally affected by partial silencing of RPS5. Taken together, results provide novel molecular insights into IRES–RPS5 interaction and unravel its functional significance in mediating internal initiation of translation.
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Affiliation(s)
- Prasanna Bhat
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Shivaprasad Shwetha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Divya Khandige Sharma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | | | | - Saumitra Das
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
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356
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Viero G, Lunelli L, Passerini A, Bianchini P, Gilbert RJ, Bernabò P, Tebaldi T, Diaspro A, Pederzolli C, Quattrone A. Three distinct ribosome assemblies modulated by translation are the building blocks of polysomes. ACTA ACUST UNITED AC 2015; 208:581-96. [PMID: 25713412 PMCID: PMC4347638 DOI: 10.1083/jcb.201406040] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translation is increasingly recognized as a central control layer of gene expression in eukaryotic cells. The overall organization of mRNA and ribosomes within polysomes, as well as the possible role of this organization in translation are poorly understood. Here we show that polysomes are primarily formed by three distinct classes of ribosome assemblies. We observe that these assemblies can be connected by naked RNA regions of the transcript. We show that the relative proportions of the three classes of ribosome assemblies reflect, and probably dictate, the level of translational activity. These results reveal the existence of recurrent supra-ribosomal building blocks forming polysomes and suggest the presence of unexplored translational controls embedded in the polysome structure.
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Affiliation(s)
- Gabriella Viero
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, 38123 Povo, Italy Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
| | - Lorenzo Lunelli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, 38123 Povo, Italy
| | - Andrea Passerini
- Department of Information Engineering and Computer Science, University of Trento, 38123 Povo, Italy
| | - Paolo Bianchini
- Nanophysics Department, Italian Institute of Technology, 16163 Genova, Italy
| | - Robert J Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, England, UK
| | - Paola Bernabò
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, 38123 Povo, Italy
| | - Toma Tebaldi
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
| | - Alberto Diaspro
- Nanophysics Department, Italian Institute of Technology, 16163 Genova, Italy
| | - Cecilia Pederzolli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, 38123 Povo, Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento, 38123 Mattarello, Italy
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357
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Abstract
The proteome of cells is synthesized by ribosomes, complex ribonucleoproteins that in eukaryotes contain 79-80 proteins and four ribosomal RNAs (rRNAs) more than 5,400 nucleotides long. How these molecules assemble together and how their assembly is regulated in concert with the growth and proliferation of cells remain important unanswered questions. Here, we review recently emerging principles to understand how eukaryotic ribosomal proteins drive ribosome assembly in vivo. Most ribosomal proteins assemble with rRNA cotranscriptionally; their association with nascent particles is strengthened as assembly proceeds. Each subunit is assembled hierarchically by sequential stabilization of their subdomains. The active sites of both subunits are constructed last, perhaps to prevent premature engagement of immature ribosomes with active subunits. Late-assembly intermediates undergo quality-control checks for proper function. Mutations in ribosomal proteins that affect mostly late steps lead to ribosomopathies, diseases that include a spectrum of cell type-specific disorders that often transition from hypoproliferative to hyperproliferative growth.
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Affiliation(s)
- Jesus de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, E-41013 Sevilla, Spain
- Departamento de Genetica, Universidad de Sevilla, E-41013 Sevilla, Spain
| | - Katrin Karbstein
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458
| | - John L Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
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358
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Ghosh A, Komar AA. Eukaryote-specific extensions in ribosomal proteins of the small subunit: Structure and function. ACTA ACUST UNITED AC 2015; 3:e999576. [PMID: 26779416 DOI: 10.1080/21690731.2014.999576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/03/2014] [Accepted: 12/12/2014] [Indexed: 01/05/2023]
Abstract
High-resolution structures of yeast ribosomes have improved our understanding of the architecture and organization of eukaryotic rRNA and proteins, as well as eukaryote-specific extensions present in some conserved ribosomal proteins. Despite this progress, assignment of specific functions to individual proteins and/or eukaryote-specific protein extensions remains challenging. It has been suggested that eukaryote-specific extensions of conserved proteins from the small ribosomal subunit may facilitate eukaryote-specific reactions in the initiation phase of protein synthesis. This review summarizes emerging data describing the structural and functional significance of eukaryote-specific extensions of conserved small ribosomal subunit proteins, particularly their possible roles in recruitment and spatial organization of eukaryote-specific initiation factors.
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Affiliation(s)
- Arnab Ghosh
- Center for Gene Regulation in Health and Disease; Department of Biological, Geological and Environmental Sciences; Cleveland State University ; Cleveland, OH USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease; Department of Biological, Geological and Environmental Sciences; Cleveland State University ; Cleveland, OH USA
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359
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Graifer D, Karpova G. Roles of ribosomal proteins in the functioning of translational machinery of eukaryotes. Biochimie 2015; 109:1-17. [DOI: 10.1016/j.biochi.2014.11.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 11/18/2014] [Indexed: 11/16/2022]
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360
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DiGiacomo V, Meruelo D. Looking into laminin receptor: critical discussion regarding the non-integrin 37/67-kDa laminin receptor/RPSA protein. Biol Rev Camb Philos Soc 2015; 91:288-310. [PMID: 25630983 DOI: 10.1111/brv.12170] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/04/2014] [Accepted: 12/08/2014] [Indexed: 02/06/2023]
Abstract
The 37/67-kDa laminin receptor (LAMR/RPSA) was originally identified as a 67-kDa binding protein for laminin, an extracellular matrix glycoprotein that provides cellular adhesion to the basement membrane. LAMR has evolutionary origins, however, as a 37-kDa RPS2 family ribosomal component. Expressed in all domains of life, RPS2 proteins have been shown to have remarkably diverse physiological roles that vary across species. Contributing to laminin binding, ribosome biogenesis, cytoskeletal organization, and nuclear functions, this protein governs critical cellular processes including growth, survival, migration, protein synthesis, development, and differentiation. Unsurprisingly given its purview, LAMR has been associated with metastatic cancer, neurodegenerative disease and developmental abnormalities. Functioning in a receptor capacity, this protein also confers susceptibility to bacterial and viral infection. LAMR is clearly a molecule of consequence in human disease, directly mediating pathological events that make it a prime target for therapeutic interventions. Despite decades of research, there are still a large number of open questions regarding the cellular biology of LAMR, the nature of its ability to bind laminin, the function of its intrinsically disordered C-terminal region and its conversion from 37 to 67 kDa. This review attempts to convey an in-depth description of the complexity surrounding this multifaceted protein across functional, structural and pathological aspects.
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Affiliation(s)
- Vincent DiGiacomo
- Department of Pathology, New York University School of Medicine, 180 Varick Street, New York, NY 10014, U.S.A
| | - Daniel Meruelo
- Department of Pathology, New York University School of Medicine, 180 Varick Street, New York, NY 10014, U.S.A.,NYU Cancer Institute, 550 First Avenue, New York, NY 10016, U.S.A.,NYU Gene Therapy Center, 550 First Avenue, New York, NY 10016, U.S.A
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361
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Shao S, Brown A, Santhanam B, Hegde RS. Structure and assembly pathway of the ribosome quality control complex. Mol Cell 2015; 57:433-44. [PMID: 25578875 PMCID: PMC4321881 DOI: 10.1016/j.molcel.2014.12.015] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/07/2014] [Accepted: 12/05/2014] [Indexed: 12/11/2022]
Abstract
During ribosome-associated quality control, stalled ribosomes are split into subunits and the 60S-housed nascent polypeptides are poly-ubiquitinated by Listerin. How this low-abundance ubiquitin ligase targets rare stall-generated 60S among numerous empty 60S is unknown. Here, we show that Listerin specificity for nascent chain-60S complexes depends on nuclear export mediator factor (NEMF). The 3.6 Å cryo-EM structure of a nascent chain-containing 60S-Listerin-NEMF complex revealed that NEMF makes multiple simultaneous contacts with 60S and peptidyl-tRNA to sense nascent chain occupancy. Structural and mutational analyses showed that ribosome-bound NEMF recruits and stabilizes Listerin's N-terminal domain, while Listerin's C-terminal RWD domain directly contacts the ribosome to position the adjacent ligase domain near the nascent polypeptide exit tunnel. Thus, highly specific nascent chain targeting by Listerin is imparted by the avidity gained from a multivalent network of context-specific individually weak interactions, highlighting a new principle of client recognition during protein quality control.
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Affiliation(s)
- Sichen Shao
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Alan Brown
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Balaji Santhanam
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Ramanujan S Hegde
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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362
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C.P.van Zundert G, M.J.J. Bonvin A. Fast and sensitive rigid-body fitting into cryo-EM density maps with PowerFit. AIMS BIOPHYSICS 2015. [DOI: 10.3934/biophy.2015.2.73] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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363
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Miettinen TP, Björklund M. Modified ribosome profiling reveals high abundance of ribosome protected mRNA fragments derived from 3' untranslated regions. Nucleic Acids Res 2014; 43:1019-34. [PMID: 25550424 PMCID: PMC4333376 DOI: 10.1093/nar/gku1310] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Ribosome profiling identifies ribosome positions on translated mRNAs. A prominent feature of published datasets is the near complete absence of ribosomes in 3′ untranslated regions (3′UTR) although substantial ribosome density can be observed on non-coding RNAs. Here we perform ribosome profiling in cultured Drosophila and human cells and show that different features of translation are revealed depending on the nuclease and the digestion conditions used. Most importantly, we observe high abundance of ribosome protected fragments in 3′UTRs of thousands of genes without manipulation of translation termination. Affinity purification of ribosomes indicates that the 3′UTR reads originate from ribosome protected fragments. Association of ribosomes with the 3′UTR may be due to ribosome migration through the stop codon or 3′UTR mRNA binding to ribosomes on the coding sequence. This association depends primarily on the relative length of the 3′UTR and may be related to translational regulation or ribosome recycling, for which the efficiency is known to inversely correlate with 3′UTR length. Together our results indicate that ribosome profiling is highly dependent on digestion conditions and that ribosomes commonly associate with the 3′UTR, which may have a role in translational regulation.
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Affiliation(s)
- Teemu P Miettinen
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, DD1 5EH Dundee, Scotland, UK
| | - Mikael Björklund
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, DD1 5EH Dundee, Scotland, UK
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364
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Abstract
UNLABELLED Influenza A virus (IAV) infections are influenced by type 1 interferon-mediated antiviral defenses and by viral countermeasures to these defenses. When IAV NS1 protein is disabled, RNase L restricts virus replication; however, the RNAs targeted for cleavage by RNase L under these conditions have not been defined. In this study, we used deep-sequencing methods to identify RNase L cleavage sites within host and viral RNAs from IAV PR8ΔNS1-infected A549 cells. Short hairpin RNA knockdown of RNase L allowed us to distinguish between RNase L-dependent and RNase L-independent cleavage sites. RNase L-dependent cleavage sites were evident at discrete locations in IAV RNA segments (both positive and negative strands). Cleavage in PB2, PB1, and PA genomic RNAs suggests that viral RNPs are susceptible to cleavage by RNase L. Prominent amounts of cleavage mapped to specific regions within IAV RNAs, including some areas of increased synonymous-site conservation. Among cellular RNAs, RNase L-dependent cleavage was most frequent at precise locations in rRNAs. Our data show that RNase L targets specific sites in both host and viral RNAs to restrict influenza virus replication when NS1 protein is disabled. IMPORTANCE RNase L is a critical component of interferon-regulated and double-stranded-RNA-activated antiviral host responses. We sought to determine how RNase L exerts its antiviral activity during influenza virus infection. We enhanced the antiviral activity of RNase L by disabling a viral protein, NS1, that inhibits the activation of RNase L. Then, using deep-sequencing methods, we identified the host and viral RNAs targeted by RNase L. We found that RNase L cleaved viral RNAs and rRNAs at very precise locations. The direct cleavage of IAV RNAs by RNase L highlights an intimate battle between viral RNAs and an antiviral endonuclease.
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365
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Gatsogiannis C, Hofnagel O, Markl J, Raunser S. Structure of mega-hemocyanin reveals protein origami in snails. Structure 2014; 23:93-103. [PMID: 25482543 DOI: 10.1016/j.str.2014.10.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/22/2014] [Accepted: 10/07/2014] [Indexed: 12/26/2022]
Abstract
Mega-hemocyanin is a 13.5 MDa oxygen transporter found in the hemolymph of some snails. Similar to typical gastropod hemocyanins, it is composed of 400 kDa building blocks but has additional 550 kDa subunits. Together, they form a large, completely filled cylinder. The structural basis for this highly complex protein packing is not known so far. Here, we report the electron cryomicroscopy (cryo-EM) structure of mega-hemocyanin complexes from two different snail species. The structures reveal that mega-hemocyanin is composed of flexible building blocks that differ in their conformation, but not in their primary structure. Like a protein origami, these flexible blocks are optimally packed, implementing different local symmetries and pseudosymmetries. A comparison between the two structures suggests a surprisingly simple evolutionary mechanism leading to these large oxygen transporters.
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Affiliation(s)
- Christos Gatsogiannis
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany.
| | - Oliver Hofnagel
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Jürgen Markl
- Institute of Zoology, Johannes Gutenberg University, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany.
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366
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Sloan KE, Leisegang MS, Doebele C, Ramírez AS, Simm S, Safferthal C, Kretschmer J, Schorge T, Markoutsa S, Haag S, Karas M, Ebersberger I, Schleiff E, Watkins NJ, Bohnsack MT. The association of late-acting snoRNPs with human pre-ribosomal complexes requires the RNA helicase DDX21. Nucleic Acids Res 2014; 43:553-64. [PMID: 25477391 PMCID: PMC4288182 DOI: 10.1093/nar/gku1291] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Translation fidelity and efficiency require multiple ribosomal (r)RNA modifications that are mostly mediated by small nucleolar (sno)RNPs during ribosome production. Overlapping basepairing of snoRNAs with pre-rRNAs often necessitates sequential and efficient association and dissociation of the snoRNPs, however, how such hierarchy is established has remained unknown so far. Here, we identify several late-acting snoRNAs that bind pre-40S particles in human cells and show that their association and function in pre-40S complexes is regulated by the RNA helicase DDX21. We map DDX21 crosslinking sites on pre-rRNAs and show their overlap with the basepairing sites of the affected snoRNAs. While DDX21 activity is required for recruitment of the late-acting snoRNAs SNORD56 and SNORD68, earlier snoRNAs are not affected by DDX21 depletion. Together, these observations provide an understanding of the timing and ordered hierarchy of snoRNP action in pre-40S maturation and reveal a novel mode of regulation of snoRNP function by an RNA helicase in human cells.
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Affiliation(s)
- Katherine E Sloan
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany
| | - Matthias S Leisegang
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany
| | - Carmen Doebele
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany
| | - Ana S Ramírez
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany
| | - Stefan Simm
- Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany
| | - Charlotta Safferthal
- Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany
| | - Jens Kretschmer
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany
| | - Tobias Schorge
- Institute of Pharmaceutical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | - Stavroula Markoutsa
- Institute of Pharmaceutical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | - Sara Haag
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany
| | - Michael Karas
- Institute of Pharmaceutical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | - Ingo Ebersberger
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt, Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany Cluster of Excellence Macromolecular Complexes, Goethe University, 60438 Frankfurt, Germany
| | - Nicholas J Watkins
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Markus T Bohnsack
- Institute for Molecular Biology, Göttingen University Medical Department, 37073 Göttingen, Germany Institute for Molecular Biosciences, Goethe University, 60438 Frankfurt, Germany Cluster of Excellence Macromolecular Complexes, Goethe University, 60438 Frankfurt, Germany Göttingen Centre for Molecular Biosciences, Georg-August-University, 37073 Göttingen, Germany
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367
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Comparison of inter- and intraspecies variation in humans and fruit flies. GENOMICS DATA 2014; 3:49-54. [PMID: 26484147 PMCID: PMC4536057 DOI: 10.1016/j.gdata.2014.11.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 12/17/2022]
Abstract
Variation is essential to species survival and adaptation during evolution. This variation is conferred by the imperfection of biochemical processes, such as mutations and alterations in DNA sequences, and can also be seen within genomes through processes such as the generation of antibodies. Recent sequencing projects have produced multiple versions of the genomes of humans and fruit flies (Drosophila melanogaster). These give us a chance to study how individual gene sequences vary within and between species. Here we arranged human and fly genes in orthologous pairs and compared such within-species variability with their degree of conservation between flies and humans. We observed that a significant number of proteins associated with mRNA translation are highly conserved between species and yet are highly variable within each species. The fact that we observe this in two species whose lineages separated more than 700 million years ago suggests that this is the result of a very ancient process. We hypothesize that this effect might be attributed to a positive selection for variability of virus-interacting proteins that confers a general resistance to viral hijacking of the mRNA translation machinery within populations. Our analysis points to this and to other processes resulting in positive selection for gene variation.
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368
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Gopanenko AV, Malygin AA, Karpova GG. Exploring human 40S ribosomal proteins binding to the 18S rRNA fragment containing major 3'-terminal domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1854:101-9. [PMID: 25462191 DOI: 10.1016/j.bbapap.2014.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/10/2014] [Accepted: 11/04/2014] [Indexed: 10/24/2022]
Abstract
Association of ribosomal proteins with rRNA during assembly of ribosomal subunits is an intricate process, which is strictly regulated in vivo. As for the assembly in vitro, it was reported so far only for prokaryotic subunits. Bacterial ribosomal proteins are capable of selective binding to 16S rRNA as well as to its separate morphological domains. In this work, we explored binding of total protein of human 40S ribosomal subunit to the RNA transcript corresponding to the major 3'-domain of 18S rRNA. We showed that the resulting ribonucleoprotein particles contained almost all of the expected ribosomal proteins, whose binding sites are located in this 18S rRNA domain in the 40S subunit, together with several nonspecific proteins. The binding in solution was accompanied with aggregation of the RNA-protein complexes. Ribosomal proteins bound to the RNA transcript protected from chemical modification mostly those 18S rRNA nucleotides that are known to be involved in binding with the proteins in the 40S subunit and thereby demonstrated their ability to selectively bind to the rRNA in vitro. The possible implication of unstructured extensions of eukaryotic ribosomal proteins in their nonspecific binding with rRNA and in subsequent aggregation of the resulting complexes is discussed.
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Affiliation(s)
- Alexander V Gopanenko
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Alexey A Malygin
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Galina G Karpova
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
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369
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King HA, Gerber AP. Translatome profiling: methods for genome-scale analysis of mRNA translation. Brief Funct Genomics 2014; 15:22-31. [PMID: 25380596 DOI: 10.1093/bfgp/elu045] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During the past decade, there has been a rapidly increased appreciation of the role of translation as a key regulatory node in gene expression. Thereby, the development of methods to infer the translatome, which refers to the entirety of mRNAs associated with ribosomes for protein synthesis, has facilitated the discovery of new principles and mechanisms of translation and expanded our view of the underlying logic of protein synthesis. Here, we review the three main methodologies for translatome analysis, and we highlight some of the recent discoveries made using each technique. We first discuss polysomal profiling, a classical technique that involves the separation of mRNAs depending on the number of bound ribosomes using a sucrose gradient, and which has been combined with global analysis tools such as DNA microarrays or high-throughput RNA sequencing to identify the RNAs in polysomal fractions. We then introduce ribosomal profiling, a recently established technique that enables the mapping of ribosomes along mRNAs at near-nucleotide resolution on a global scale. We finally refer to ribosome affinity purification techniques that are based on the cell-type-specific expression of tagged ribosomal proteins, allowing the capture of translatomes from specialized cells in organisms. We discuss the advantages and disadvantages of these three main techniques in the pursuit of defining the translatome, and we speculate about future developments.
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370
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Si D, He J. Tracing Beta Strands Using StrandTwister from Cryo-EM Density Maps at Medium Resolutions. Structure 2014; 22:1665-76. [DOI: 10.1016/j.str.2014.08.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 08/07/2014] [Accepted: 08/08/2014] [Indexed: 10/24/2022]
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371
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Henras AK, Plisson-Chastang C, O'Donohue MF, Chakraborty A, Gleizes PE. An overview of pre-ribosomal RNA processing in eukaryotes. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:225-42. [PMID: 25346433 PMCID: PMC4361047 DOI: 10.1002/wrna.1269] [Citation(s) in RCA: 391] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/04/2014] [Accepted: 08/29/2014] [Indexed: 12/23/2022]
Abstract
Ribosomal RNAs are the most abundant and universal noncoding RNAs in living organisms. In eukaryotes, three of the four ribosomal RNAs forming the 40S and 60S subunits are borne by a long polycistronic pre-ribosomal RNA. A complex sequence of processing steps is required to gradually release the mature RNAs from this precursor, concomitant with the assembly of the 79 ribosomal proteins. A large set of trans-acting factors chaperone this process, including small nucleolar ribonucleoparticles. While yeast has been the gold standard for studying the molecular basis of this process, recent technical advances have allowed to further define the mechanisms of ribosome biogenesis in animals and plants. This renewed interest for a long-lasting question has been fueled by the association of several genetic diseases with mutations in genes encoding both ribosomal proteins and ribosome biogenesis factors, and by the perspective of new anticancer treatments targeting the mechanisms of ribosome synthesis. A consensus scheme of pre-ribosomal RNA maturation is emerging from studies in various kinds of eukaryotic organisms. However, major differences between mammalian and yeast pre-ribosomal RNA processing have recently come to light. WIREs RNA 2015, 6:225–242. doi: 10.1002/wrna.1269
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Affiliation(s)
- Anthony K Henras
- Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse-Paul Sabatier CNRS, UMR 5099, Toulouse, France
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372
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Wawiórka L, Krokowski D, Gordiyenko Y, Krowarsch D, Robinson CV, Adam I, Grankowski N, Tchórzewski M. In vivo formation of Plasmodium falciparum ribosomal stalk - a unique mode of assembly without stable heterodimeric intermediates. Biochim Biophys Acta Gen Subj 2014; 1850:150-8. [PMID: 25450178 DOI: 10.1016/j.bbagen.2014.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/19/2014] [Accepted: 10/15/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND The ribosomal stalk composed of P-proteins constitutes a structure on the large ribosomal particle responsible for recruitment of translation factors and stimulation of factor-dependent GTP hydrolysis during translation. The main components of the stalk are P-proteins, which form a pentamer. Despite the conserved basic function of the stalk, the P-proteins do not form a uniform entity, displaying heterogeneity in the primary structure across the eukaryotic lineage. The P-proteins from protozoan parasites are among the most evolutionarily divergent stalk proteins. METHODS We have assembled P-stalk complex of Plasmodium falciparum in vivo in bacterial system using tricistronic expression cassette and provided its characteristics by biochemical and biophysical methods. RESULTS All three individual P-proteins, namely uL10/P0, P1 and P2, are indispensable for acquisition of a stable structure of the P stalk complex and the pentameric uL10/P0-(P1-P2)₂form represents the most favorable architecture for parasite P-proteins. CONCLUSION The formation of P. falciparum P-stalk is driven by trilateral interaction between individual elements which represents unique mode of assembling, without stable P1-P2 heterodimeric intermediate. GENERAL SIGNIFICANCE On the basis of our mass-spectrometry analysis supported by the bacterial two-hybrid assay and biophysical analyses, a unique pathway of the parasite stalk assembling has been proposed. We suggest that the absence of P1/P2 heterodimer, and the formation of a stable pentamer in the presence of all three proteins, indicate a one-step formation to be the main pathway for the vital ribosomal stalk assembly, whereas the P2 homo-oligomer may represent an off-pathway product with physiologically important nonribosomal role.
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Affiliation(s)
- Leszek Wawiórka
- Department of Molecular Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Dawid Krokowski
- Department of Molecular Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Yuliya Gordiyenko
- Department of Chemistry, University of Oxford, South Parks Rd, Oxford OX1 3QZ, UK
| | - Daniel Krowarsch
- Department of Protein Biotechnology, Faculty of Biotechnology, University of Wroclaw, Tamka 2, 50-137 Wroclaw, Poland
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, South Parks Rd, Oxford OX1 3QZ, UK
| | - Ishag Adam
- Department of Obstetrics & Gynecology, Faculty of Medicine, AlKaser Street, University of Khartoum, Khartoum, Sudan
| | - Nikodem Grankowski
- Department of Molecular Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Marek Tchórzewski
- Department of Molecular Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
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373
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Wang Y, Sun H, Du W, Blanzieri E, Viero G, Xu Y, Liang Y. Identification of essential proteins based on ranking edge-weights in protein-protein interaction networks. PLoS One 2014; 9:e108716. [PMID: 25268881 PMCID: PMC4182551 DOI: 10.1371/journal.pone.0108716] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 09/03/2014] [Indexed: 12/02/2022] Open
Abstract
Essential proteins are those that are indispensable to cellular survival and development. Existing methods for essential protein identification generally rely on knock-out experiments and/or the relative density of their interactions (edges) with other proteins in a Protein-Protein Interaction (PPI) network. Here, we present a computational method, called EW, to first rank protein-protein interactions in terms of their Edge Weights, and then identify sub-PPI-networks consisting of only the highly-ranked edges and predict their proteins as essential proteins. We have applied this method to publicly-available PPI data on Saccharomyces cerevisiae (Yeast) and Escherichia coli (E. coli) for essential protein identification, and demonstrated that EW achieves better performance than the state-of-the-art methods in terms of the precision-recall and Jackknife measures. The highly-ranked protein-protein interactions by our prediction tend to be biologically significant in both the Yeast and E. coli PPI networks. Further analyses on systematically perturbed Yeast and E. coli PPI networks through randomly deleting edges demonstrate that the proposed method is robust and the top-ranked edges tend to be more associated with known essential proteins than the lowly-ranked edges.
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Affiliation(s)
- Yan Wang
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, Changchun, China
- Department of Information and Communication Technology, University of Trento, Povo, Italy
- Computational Systems Biology Lab, Department of Biochemistry and Molecular Biology and Institute of Bioinformatics, University of Georgia, Athens, GA, United States of America
| | - Huiyan Sun
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, Changchun, China
| | - Wei Du
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, Changchun, China
| | - Enrico Blanzieri
- Department of Information and Communication Technology, University of Trento, Povo, Italy
- * E-mail: (YCL); (EB)
| | - Gabriella Viero
- Institute of Biophysics, National Research Council, University of Trento, Povo, Italy
| | - Ying Xu
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, Changchun, China
- Computational Systems Biology Lab, Department of Biochemistry and Molecular Biology and Institute of Bioinformatics, University of Georgia, Athens, GA, United States of America
| | - Yanchun Liang
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, Changchun, China
- * E-mail: (YCL); (EB)
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374
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Budkevich TV, Giesebrecht J, Behrmann E, Loerke J, Ramrath DJF, Mielke T, Ismer J, Hildebrand PW, Tung CS, Nierhaus KH, Sanbonmatsu KY, Spahn CMT. Regulation of the mammalian elongation cycle by subunit rolling: a eukaryotic-specific ribosome rearrangement. Cell 2014; 158:121-31. [PMID: 24995983 DOI: 10.1016/j.cell.2014.04.044] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/24/2014] [Accepted: 04/18/2014] [Indexed: 11/15/2022]
Abstract
The extent to which bacterial ribosomes and the significantly larger eukaryotic ribosomes share the same mechanisms of ribosomal elongation is unknown. Here, we present subnanometer resolution cryoelectron microscopy maps of the mammalian 80S ribosome in the posttranslocational state and in complex with the eukaryotic eEF1A⋅Val-tRNA⋅GMPPNP ternary complex, revealing significant differences in the elongation mechanism between bacteria and mammals. Surprisingly, and in contrast to bacterial ribosomes, a rotation of the small subunit around its long axis and orthogonal to the well-known intersubunit rotation distinguishes the posttranslocational state from the classical pretranslocational state ribosome. We term this motion "subunit rolling." Correspondingly, a mammalian decoding complex visualized in substates before and after codon recognition reveals structural distinctions from the bacterial system. These findings suggest how codon recognition leads to GTPase activation in the mammalian system and demonstrate that in mammalia subunit rolling occurs during tRNA selection.
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Affiliation(s)
- Tatyana V Budkevich
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Max-Planck Institut für Molekulare Genetik, Abteilung Vingron, AG Ribosomen, 14195 Berlin, Ihnestraße 73, Germany; Institute of Molecular Biology and Genetics, Group of Protein Biosynthesis, 03143 Kiev, Ukraine
| | - Jan Giesebrecht
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Elmar Behrmann
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Justus Loerke
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - David J F Ramrath
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Thorsten Mielke
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Max-Planck Institut für Molekulare Genetik, UltraStrukturNetzwerk, 14195 Berlin, Ihnestraße 73, Germany
| | - Jochen Ismer
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Peter W Hildebrand
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Chang-Shung Tung
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, MK710, Los Alamos, NM 87545, USA
| | - Knud H Nierhaus
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Max-Planck Institut für Molekulare Genetik, Abteilung Vingron, AG Ribosomen, 14195 Berlin, Ihnestraße 73, Germany
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, MK710, Los Alamos, NM 87545, USA; New Mexico Consortium, 4200 West Jemez Road, Suite 301, Los Alamos, New Mexico 87544, USA
| | - Christian M T Spahn
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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375
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Stokes JM, Davis JH, Mangat CS, Williamson JR, Brown ED. Discovery of a small molecule that inhibits bacterial ribosome biogenesis. eLife 2014; 3:e03574. [PMID: 25233066 PMCID: PMC4371806 DOI: 10.7554/elife.03574] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/17/2014] [Indexed: 11/29/2022] Open
Abstract
While small molecule inhibitors of the bacterial ribosome have been instrumental in
understanding protein translation, no such probes exist to study ribosome biogenesis.
We screened a diverse chemical collection that included previously approved drugs for
compounds that induced cold sensitive growth inhibition in the model bacterium
Escherichia coli. Among the most cold sensitive was lamotrigine,
an anticonvulsant drug. Lamotrigine treatment resulted in the rapid accumulation of
immature 30S and 50S ribosomal subunits at 15°C. Importantly, this was not the result
of translation inhibition, as lamotrigine was incapable of perturbing protein
synthesis in vivo or in vitro. Spontaneous suppressor mutations blocking lamotrigine
activity mapped solely to the poorly characterized domain II of translation
initiation factor IF2 and prevented the binding of lamotrigine to IF2 in vitro. This
work establishes lamotrigine as a widely available chemical probe of bacterial
ribosome biogenesis and suggests a role for E. coli IF2 in ribosome
assembly. DOI:http://dx.doi.org/10.7554/eLife.03574.001 Inside cells, molecular machines called ribosomes make proteins from instructions
that are provided by genes. The ribosomes themselves are made up of about 50 proteins
and three RNA molecules that need to be assembled like a 3-D jigsaw. In bacteria, a
group of proteins called ribosome biogenesis factors help to assemble these pieces
correctly. To study how a biological process works, scientists often look at what happens when a
component is missing or not working properly. However, this approach cannot be used
to study how ribosomes are made because stopping protein production entirely will
kill the cell. Another approach is to use chemicals to temporarily stop or slow down
a biological process, but researchers are yet to find a chemical that can do this for
ribosome assembly. To address this problem, Stokes et al. ‘screened’ 30,000 chemicals in an effort to
find one or more that could affect ribosome assembly in bacteria. The screen revealed
that a drug called lamotrigine—which is used to treat epilepsy and other conditions
in humans—could stop the assembly of ribosomes, but did not affect the production of
proteins by completed ribosomes. The experiments also suggest that initiation factor 2, a protein that is involved in
the production of other proteins, may also have a role in ribosome assembly. Another
recent study found that the equivalent of initiation factor 2 in yeast acts as a
quality control checkpoint during ribosome assembly, so the bacterial version may
also perform a similar role. It is also be possible that lamotrigine might be used to help develop a novel
mechanistic class of antibiotics. DOI:http://dx.doi.org/10.7554/eLife.03574.002
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Affiliation(s)
- Jonathan M Stokes
- Michael G DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Joseph H Davis
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States
| | - Chand S Mangat
- Michael G DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States
| | - Eric D Brown
- Michael G DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
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376
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López-Blanco JR, Chacón P. Structural modeling from electron microscopy data. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2014. [DOI: 10.1002/wcms.1199] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- José Ramón López-Blanco
- Department of Biological Physical Chemistry; Rocasolano Physical Chemistry Institute, CSIC; Madrid Spain
| | - Pablo Chacón
- Department of Biological Physical Chemistry; Rocasolano Physical Chemistry Institute, CSIC; Madrid Spain
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377
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Circular code motifs in the ribosome decoding center. Comput Biol Chem 2014; 52:9-17. [PMID: 25215650 DOI: 10.1016/j.compbiolchem.2014.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 11/20/2022]
Abstract
A translation (framing) code based on the circular code was proposed in Michel (2012) with the identification of X circular code motifs (X motifs shortly) in the bacterial rRNA of Thermus thermophilus, in particular in the ribosome decoding center. Three classes of X motifs are now identified in the rRNAs of bacteria Escherichia coli and Thermus thermophilus, archaea Pyrococcus furiosus, nuclear eukaryotes Saccharomyces cerevisiae, Triticum aestivum and Homo sapiens, and chloroplast Spinacia oleracea. The universally conserved nucleotides A1492 and A1493 in all studied rRNAs (bacteria, archaea, nuclear eukaryotes, and chloroplasts) belong to X motifs (called mAA). The conserved nucleotide G530 in rRNAs of bacteria and archaea belongs to X motifs (called mG). Furthermore, the X motif mG is also found in rRNAs of nuclear eukaryotes and chloroplasts. Finally, a potentially important X motif, called m, is identified in all studied rRNAs. With the available crystallographic structures of the Protein Data Bank PDB, we also show that these X motifs mAA, mG, and m belong to the ribosome decoding center of all studied rRNAs with possible interaction with the mRNA X motifs and the tRNA X motifs. The three classes of X motifs identified here in rRNAs of several and different organisms strengthen the concept of translation code based on the circular code.
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378
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Structures of yeast 80S ribosome-tRNA complexes in the rotated and nonrotated conformations. Structure 2014; 22:1210-1218. [PMID: 25043550 DOI: 10.1016/j.str.2014.06.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 01/10/2023]
Abstract
The structural understanding of eukaryotic translation lags behind that of translation on bacterial ribosomes. Here, we present two subnanometer resolution structures of S. cerevisiae 80S ribosome complexes formed with either one or two tRNAs and bound in response to an mRNA fragment containing the Kozak consensus sequence. The ribosomes adopt two globally different conformations that are related to each other by the rotation of the small subunit. Comparison with bacterial ribosome complexes reveals that the global structures and modes of intersubunit rotation of the yeast ribosome differ significantly from those in the bacterial counterpart, most notably in the regions involving the tRNA, small ribosomal subunit, and conserved helix 69 of the large ribosomal subunit. The structures provide insight into ribosome dynamics implicated in tRNA translocation and help elucidate the role of the Kozak fragment in positioning an open reading frame during translation initiation in eukaryotes.
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379
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Durrant JD, Amaro RE. LipidWrapper: an algorithm for generating large-scale membrane models of arbitrary geometry. PLoS Comput Biol 2014; 10:e1003720. [PMID: 25032790 PMCID: PMC4102414 DOI: 10.1371/journal.pcbi.1003720] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/21/2014] [Indexed: 11/19/2022] Open
Abstract
As ever larger and more complex biological systems are modeled in silico, approximating physiological lipid bilayers with simple planar models becomes increasingly unrealistic. In order to build accurate large-scale models of subcellular environments, models of lipid membranes with carefully considered, biologically relevant curvature will be essential. In the current work, we present a multi-scale utility called LipidWrapper capable of creating curved membrane models with geometries derived from various sources, both experimental and theoretical. To demonstrate its utility, we use LipidWrapper to examine an important mechanism of influenza virulence. A copy of the program can be downloaded free of charge under the terms of the open-source FreeBSD License from http://nbcr.ucsd.edu/lipidwrapper. LipidWrapper has been tested on all major computer operating systems.
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Affiliation(s)
- Jacob D. Durrant
- Department of Chemistry & Biochemistry, University of California San Diego, La Jolla, California, United States of America
| | - Rommie E. Amaro
- Department of Chemistry & Biochemistry, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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380
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Abstract
The torrent of RNA-seq data becoming available not only furnishes an overview of the entire transcriptome but also provides tools to focus on specific areas of interest. Our focus on the synthesis of ribosomes asked whether the abundance of mRNAs encoding ribosomal proteins (RPs) matched the equimolar need for the RPs in the assembly of ribosomes. We were at first surprised to find, in the mapping data of ENCODE and other sources, that there were nearly 100-fold differences in the level of the mRNAs encoding the different RPs. However, after correcting for the mapping ambiguities introduced by the presence of more than 2000 pseudogenes derived from RP mRNAs, we show that for 80%-90% of the RP genes, the molar ratio of mRNAs varies less than threefold, with little tissue specificity. Nevertheless, since the RPs are needed in equimolar amounts, there must be sluggish or regulated translation of the more abundant RP mRNAs and/or substantial turnover of unused RPs. In addition, seven of the RPs have subsidiary genes, three of which are pseudogenes that have been "rescued" by the introduction of promoters and/or upstream introns. Several of these are transcribed in a tissue-specific manner, e.g., RPL10L in testis and RPL3L in muscle, leading to potential variation in ribosome structure from one tissue to another. Of the 376 introns in the RP genes, a single one is alternatively spliced in a tissue-specific manner.
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381
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Kossinova O, Malygin A, Krol A, Karpova G. The SBP2 protein central to selenoprotein synthesis contacts the human ribosome at expansion segment 7L of the 28S rRNA. RNA (NEW YORK, N.Y.) 2014; 20:1046-1056. [PMID: 24850884 PMCID: PMC4114684 DOI: 10.1261/rna.044917.114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/27/2014] [Indexed: 05/31/2023]
Abstract
SBP2 is a pivotal protein component in selenoprotein synthesis. It binds the SECIS stem-loop in the 3' UTR of selenoprotein mRNA and interacts with both the specialized translation elongation factor and the ribosome at the 60S subunit. In this work, our goal was to identify the binding partners of SBP2 on the ribosome. Cross-linking experiments with bifunctional reagents demonstrated that the SBP2-binding site on the human ribosome is mainly formed by the 28S rRNA. Direct hydroxyl radical probing of the entire 28S rRNA revealed that SBP2 bound to 80S ribosomes or 60S subunits protects helix ES7L-E in expansion segment 7 of the 28S rRNA. Diepoxybutane cross-linking confirmed the interaction of SBP2 with helix ES7L-E. Additionally, binding of SBP2 to the ribosome led to increased reactivity toward chemical probes of a few bases in ES7L-E and in the universally conserved helix H89, indicative of conformational changes in the 28S rRNA in response to SBP2 binding. This study revealed for the first time that SBP2 makes direct contacts with a discrete region of the human 28S rRNA.
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Affiliation(s)
- Olga Kossinova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Alexey Malygin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Alain Krol
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Galina Karpova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
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382
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Abstract
The origins and evolution of the ribosome, 3-4 billion years ago, remain imprinted in the biochemistry of extant life and in the structure of the ribosome. Processes of ribosomal RNA (rRNA) expansion can be "observed" by comparing 3D rRNA structures of bacteria (small), yeast (medium), and metazoans (large). rRNA size correlates well with species complexity. Differences in ribosomes across species reveal that rRNA expansion segments have been added to rRNAs without perturbing the preexisting core. Here we show that rRNA growth occurs by a limited number of processes that include inserting a branch helix onto a preexisting trunk helix and elongation of a helix. rRNA expansions can leave distinctive atomic resolution fingerprints, which we call "insertion fingerprints." Observation of insertion fingerprints in the ribosomal common core allows identification of probable ancestral expansion segments. Conceptually reversing these expansions allows extrapolation backward in time to generate models of primordial ribosomes. The approach presented here provides insight to the structure of pre-last universal common ancestor rRNAs and the subsequent expansions that shaped the peptidyl transferase center and the conserved core. We infer distinct phases of ribosomal evolution through which ribosomal particles evolve, acquiring coding and translocation, and extending and elaborating the exit tunnel.
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383
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Functional divergence between the two P1-P2 stalk dimers on the ribosome in their interaction with ricin A chain. Biochem J 2014; 460:59-67. [PMID: 24576056 DOI: 10.1042/bj20140014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The eukaryotic stalk, which is responsible for the recruitment of translation factors, is a pentamer containing two P1-P2 dimers with unclear modes of action. In Saccharomyces cerevisiae, P1/P2 proteins (individual P1 and P2 proteins) are organized into two distinct dimers, P1A-P2B and P1B-P2A. To investigate the functional contribution of each dimer on the ribosome, RTA (ricin A chain), which binds to the stalk to depurinate the SRL (sarcin/ricin loop), was used as a molecular probe in yeast mutants in which the binding site for one or the other dimer on P0 was deleted. Ribosome depurination and toxicity of RTA were greatly reduced in mutants containing only P1A-P2B on the ribosome, whereas those with only P1B-P2A were reduced less in depurination and were unaffected in toxicity. Ribosomes bearing P1B-P2A were depurinated by RTA at a similar level as wild-type, but ribosomes bearing P1A-P2B were depurinated at a much lower level in vitro. The latter ribosomes showed the lowest association and almost no dissociation with RTA by surface plasmon resonance. These results indicate that the P1B-P2A dimer is more critical for facilitating the access of RTA to the SRL, providing the first in vivo evidence for functional divergence between the two stalk dimers on the ribosome.
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384
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Ivanov AV, Malygin AA, Karpova GG. Common features in arrangements of ribosomal protein S26e binding sites on its pre-mRNA and 18S rRNA. Mol Biol 2014. [DOI: 10.1134/s002689331403008x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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385
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Voorhees RM, Fernández IS, Scheres SHW, Hegde RS. Structure of the mammalian ribosome-Sec61 complex to 3.4 Å resolution. Cell 2014; 157:1632-43. [PMID: 24930395 PMCID: PMC4081569 DOI: 10.1016/j.cell.2014.05.024] [Citation(s) in RCA: 258] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 05/14/2014] [Accepted: 05/20/2014] [Indexed: 11/27/2022]
Abstract
Cotranslational protein translocation is a universally conserved process for secretory and membrane protein biosynthesis. Nascent polypeptides emerging from a translating ribosome are either transported across or inserted into the membrane via the ribosome-bound Sec61 channel. Here, we report structures of a mammalian ribosome-Sec61 complex in both idle and translating states, determined to 3.4 and 3.9 Å resolution. The data sets permit building of a near-complete atomic model of the mammalian ribosome, visualization of A/P and P/E hybrid-state tRNAs, and analysis of a nascent polypeptide in the exit tunnel. Unprecedented chemical detail is observed for both the ribosome-Sec61 interaction and the conformational state of Sec61 upon ribosome binding. Comparison of the maps from idle and translating complexes suggests how conformational changes to the Sec61 channel could facilitate translocation of a secreted polypeptide. The high-resolution structure of the mammalian ribosome-Sec61 complex provides a valuable reference for future functional and structural studies. A near-complete atomic resolution structure of the mammalian ribosome Snapshot of a translating ribosome with hybrid state tRNAs and nascent polypeptide Structures of the Sec61 translocon bound to idle and translating ribosomes Molecular details of the residues involved in the ribosome-Sec61 interaction
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Affiliation(s)
- Rebecca M Voorhees
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Israel S Fernández
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Ramanujan S Hegde
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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386
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Visualization of a polytopic membrane protein during SecY-mediated membrane insertion. Nat Commun 2014; 5:4103. [PMID: 24912953 DOI: 10.1038/ncomms5103] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/13/2014] [Indexed: 01/16/2023] Open
Abstract
The biogenesis of polytopic membrane proteins occurs co-translationally on ribosomes that are tightly bound to a membrane-embedded protein-conducting channel: the Sec-complex. The path that is followed by nascent proteins inside the ribosome and the Sec-complex is relatively well established; however, it is not clear what the fate of the N-terminal transmembrane domains (TMDs) of polytopic membrane proteins is when the C-terminal TMDs domains are not yet synthesized. Here, we present the sub-nanometer cryo-electron microscopy structure of an in vivo generated ribosome-SecY complex that carries a membrane insertion intermediate of proteorhodopsin (PR). The structure reveals a pre-opened Sec-complex and the first two TMDs of PR already outside the SecY complex directly in front of its proposed lateral gate. Thus, our structure is in agreement with positioning of N-terminal TMDs at the periphery of SecY, and in addition, it provides clues for the molecular mechanism underlying membrane protein topogenesis.
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387
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Wong W, Bai XC, Brown A, Fernandez IS, Hanssen E, Condron M, Tan YH, Baum J, Scheres SHW. Cryo-EM structure of the Plasmodium falciparum 80S ribosome bound to the anti-protozoan drug emetine. eLife 2014; 3. [PMID: 24913268 PMCID: PMC4086275 DOI: 10.7554/elife.03080] [Citation(s) in RCA: 220] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/06/2014] [Indexed: 12/17/2022] Open
Abstract
Malaria inflicts an enormous burden on global human health. The emergence of parasite resistance to front-line drugs has prompted a renewed focus on the repositioning of clinically approved drugs as potential anti-malarial therapies. Antibiotics that inhibit protein translation are promising candidates for repositioning. We have solved the cryo-EM structure of the cytoplasmic ribosome from the human malaria parasite, Plasmodium falciparum, in complex with emetine at 3.2 Å resolution. Emetine is an anti-protozoan drug used in the treatment of ameobiasis that also displays potent anti-malarial activity. Emetine interacts with the E-site of the ribosomal small subunit and shares a similar binding site with the antibiotic pactamycin, thereby delivering its therapeutic effect by blocking mRNA/tRNA translocation. As the first cryo-EM structure that visualizes an antibiotic bound to any ribosome at atomic resolution, this establishes cryo-EM as a powerful tool for screening and guiding the design of drugs that target parasite translation machinery. DOI:http://dx.doi.org/10.7554/eLife.03080.001 Each year, malaria kills more than 600,000 people, mostly children younger than 5 years old. Humans who have been bitten by mosquitoes infected with malaria-causing parasites become ill as the parasites rapidly multiply in blood cells. Although there are several drugs that are currently used to treat malaria, the parasites are rapidly developing resistance to them, setting off an urgent hunt for new malaria drugs. Developing new antimalarial medications from scratch is likely to take decades—too long to combat the current public health threat posed by emerging strains of drug-resistant parasites. To speed up the process, scientists are investigating whether drugs developed for other illnesses may also act as therapies for malaria, either when used alone or in combination with existing malaria drugs. Certain antibiotics—including one called emetine—have already shown promise as antimalarial drugs. These antibiotics prevent the parasites from multiplying by interfering with the ribosome—the part of a cell that builds new proteins. However, humans become ill after taking emetine for long periods because it also blocks the production of human proteins. Tweaking emetine so that it acts only against the production of parasite proteins would make it a safer malaria treatment. To do this, scientists must first map the precise interactions between the drug and the ribosomes in parasites. Wong et al. have now used a technique called cryo-electron microscopy to examine the ribosome of the most virulent form of malaria parasite. This technique uses very cold temperatures to rapidly freeze molecules, allowing scientists to look at molecular-level details without distorting the structure of the molecule—a problem sometimes encountered in other techniques. The images of the parasitic ribosome taken by Wong, Bai, Brown et al. show that emetine binds to the end of the ribosome where the instructions for how to assemble amino acids into a protein are copied from strands of RNA. In addition, the images revealed features of the parasitic ribosome that are not found in the human form. Drug makers could exploit these features to improve emetine so that it more specifically targets the production of proteins by the parasite and is less toxic to humans. DOI:http://dx.doi.org/10.7554/eLife.03080.002
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Affiliation(s)
- Wilson Wong
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Xiao-chen Bai
- Structural Studies, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alan Brown
- Structural Studies, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Israel S Fernandez
- Structural Studies, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Eric Hanssen
- Electron Microscopy Unit, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - Melanie Condron
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Yan Hong Tan
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Jake Baum
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Sjors H W Scheres
- Structural Studies, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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388
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Bernier CR, Petrov AS, Waterbury CC, Jett J, Li F, Freil LE, Xiong X, Wang L, Migliozzi BLR, Hershkovits E, Xue Y, Hsiao C, Bowman JC, Harvey SC, Grover MA, Wartell ZJ, Williams LD. RiboVision suite for visualization and analysis of ribosomes. Faraday Discuss 2014; 169:195-207. [PMID: 25340471 DOI: 10.1039/c3fd00126a] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
RiboVision is a visualization and analysis tool for the simultaneous display of multiple layers of diverse information on primary (1D), secondary (2D), and three-dimensional (3D) structures of ribosomes. The ribosome is a macromolecular complex containing ribosomal RNA and ribosomal proteins and is a key component of life responsible for the synthesis of proteins in all living organisms. RiboVision is intended for rapid retrieval, analysis, filtering, and display of a variety of ribosomal data. Preloaded information includes 1D, 2D, and 3D structures augmented by base-pairing, base-stacking, and other molecular interactions. RiboVision is preloaded with rRNA secondary structures, rRNA domains and helical structures, phylogeny, crystallographic thermal factors, etc. RiboVision contains structures of ribosomal proteins and a database of their molecular interactions with rRNA. RiboVision contains preloaded structures and data for two bacterial ribosomes (Thermus thermophilus and Escherichia coli), one archaeal ribosome (Haloarcula marismortui), and three eukaryotic ribosomes (Saccharomyces cerevisiae, Drosophila melanogaster, and Homo sapiens). RiboVision revealed several major discrepancies between the 2D and 3D structures of the rRNAs of the small and large subunits (SSU and LSU). Revised structures mapped with a variety of data are available in RiboVision as well as in a public gallery (). RiboVision is designed to allow users to distill complex data quickly and to easily generate publication-quality images of data mapped onto secondary structures. Users can readily import and analyze their own data in the context of other work. This package allows users to import and map data from CSV files directly onto 1D, 2D, and 3D levels of structure. RiboVision has features in rough analogy with web-based map services capable of seamlessly switching the type of data displayed and the resolution or magnification of the display. RiboVision is available at .
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Affiliation(s)
- Chad R Bernier
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
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389
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Whole-exome sequencing and functional studies identify RPS29 as a novel gene mutated in multicase Diamond-Blackfan anemia families. Blood 2014; 124:24-32. [PMID: 24829207 DOI: 10.1182/blood-2013-11-540278] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Diamond-Blackfan anemia (DBA) is a cancer-prone inherited bone marrow failure syndrome. Approximately half of DBA patients have a germ-line mutation in a ribosomal protein gene. We used whole-exome sequencing to identify disease-causing genes in 2 large DBA families. After filtering, 1 nonsynonymous mutation (p.I31F) in the ribosomal protein S29 (RPS29[AUQ1]) gene was present in all 5 DBA-affected individuals and the obligate carrier, and absent from the unaffected noncarrier parent in 1 DBA family. A second DBA family was found to have a different nonsynonymous mutation (p.I50T) in RPS29. Both mutations are amino acid substitutions in exon 2 predicted to be deleterious and resulted in haploinsufficiency of RPS29 expression compared with wild-type RPS29 expression from an unaffected control. The DBA proband with the p.I31F RPS29 mutation had a pre-ribosomal RNA (rRNA) processing defect compared with the healthy control. We demonstrated that both RPS29 mutations failed to rescue the defective erythropoiesis in the rps29(-/-) mutant zebra fish DBA model. RPS29 is a component of the small 40S ribosomal subunit and essential for rRNA processing and ribosome biogenesis. We uncovered a novel DBA causative gene, RPS29, and showed that germ-line mutations in RPS29 can cause a defective erythropoiesis phenotype using a zebra fish model.
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390
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Grotwinkel JT, Wild K, Segnitz B, Sinning I. SRP RNA remodeling by SRP68 explains its role in protein translocation. Science 2014; 344:101-4. [PMID: 24700861 DOI: 10.1126/science.1249094] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The signal recognition particle (SRP) is central to membrane protein targeting; SRP RNA is essential for SRP assembly, elongation arrest, and activation of SRP guanosine triphosphatases. In eukaryotes, SRP function relies on the SRP68-SRP72 heterodimer. We present the crystal structures of the RNA-binding domain of SRP68 (SRP68-RBD) alone and in complex with SRP RNA and SRP19. SRP68-RBD is a tetratricopeptide-like module that binds to a RNA three-way junction, bends the RNA, and inserts an α-helical arginine-rich motif (ARM) into the major groove. The ARM opens the conserved 5f RNA loop, which in ribosome-bound SRP establishes a contact to ribosomal RNA. Our data provide the structural basis for eukaryote-specific, SRP68-driven RNA remodeling required for protein translocation.
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Affiliation(s)
- Jan Timo Grotwinkel
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
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391
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Graifer D, Malygin A, Zharkov DO, Karpova G. Eukaryotic ribosomal protein S3: A constituent of translational machinery and an extraribosomal player in various cellular processes. Biochimie 2014; 99:8-18. [DOI: 10.1016/j.biochi.2013.11.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/05/2013] [Indexed: 01/26/2023]
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392
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Thalassinos K, Pandurangan AP, Xu M, Alber F, Topf M. Conformational States of macromolecular assemblies explored by integrative structure calculation. Structure 2014; 21:1500-8. [PMID: 24010709 PMCID: PMC3988990 DOI: 10.1016/j.str.2013.08.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 08/10/2013] [Accepted: 08/12/2013] [Indexed: 12/22/2022]
Abstract
A detailed description of macromolecular assemblies in multiple conformational states can be very valuable for understanding cellular processes. At present, structural determination of most assemblies in different biologically relevant conformations cannot be achieved by a single technique and thus requires an integrative approach that combines information from multiple sources. Different techniques require different computational methods to allow efficient and accurate data processing and analysis. Here, we summarize the latest advances and future challenges in computational methods that help the interpretation of data from two techniques—mass spectrometry and three-dimensional cryo-electron microscopy (with focus on alignment and classification of heterogeneous subtomograms from cryo-electron tomography). We evaluate how new developments in these two broad fields will lead to further integration with atomic structures to broaden our picture of the dynamic behavior of assemblies in their native environment.
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Affiliation(s)
- Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
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393
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Partial methylation at Am100 in 18S rRNA of baker's yeast reveals ribosome heterogeneity on the level of eukaryotic rRNA modification. PLoS One 2014; 9:e89640. [PMID: 24586927 PMCID: PMC3938493 DOI: 10.1371/journal.pone.0089640] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 01/24/2014] [Indexed: 11/30/2022] Open
Abstract
Ribosome heterogeneity is of increasing biological significance and several examples have been described for multicellular and single cells organisms. In here we show for the first time a variation in ribose methylation within the 18S rRNA of Saccharomyces cerevisiae. Using RNA-cleaving DNAzymes, we could specifically demonstrate that a significant amount of S. cerevisiae ribosomes are not methylated at 2′-O-ribose of A100 residue in the 18S rRNA. Furthermore, using LC-UV-MS/MS of a respective 18S rRNA fragment, we could not only corroborate the partial methylation at A100, but could also quantify the methylated versus non-methylated A100 residue. Here, we exhibit that only 68% of A100 in the 18S rRNA of S.cerevisiae are methylated at 2′-O ribose sugar. Polysomes also contain a similar heterogeneity for methylated Am100, which shows that 40S ribosome subunits with and without Am100 participate in translation. Introduction of a multicopy plasmid containing the corresponding methylation guide snoRNA gene SNR51 led to an increased A100 methylation, suggesting the cellular snR51 level to limit the extent of this modification. Partial rRNA modification demonstrates a new level of ribosome heterogeneity in eukaryotic cells that might have substantial impact on regulation and fine-tuning of the translation process.
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394
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Mechanism of Tc toxin action revealed in molecular detail. Nature 2014; 508:61-5. [DOI: 10.1038/nature13015] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 01/10/2014] [Indexed: 12/20/2022]
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395
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Villar M, Popara M, Ayllón N, Fernández de Mera IG, Mateos-Hernández L, Galindo RC, Manrique M, Tobes R, de la Fuente J. A systems biology approach to the characterization of stress response in Dermacentor reticulatus tick unfed larvae. PLoS One 2014; 9:e89564. [PMID: 24586875 PMCID: PMC3931811 DOI: 10.1371/journal.pone.0089564] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 01/21/2014] [Indexed: 11/19/2022] Open
Abstract
Background Dermacentor reticulatus (Fabricius, 1794) is distributed in Europe and Asia where it infests and transmits disease-causing pathogens to humans, pets and other domestic and wild animals. However, despite its role as a vector of emerging or re-emerging diseases, very little information is available on the genome, transcriptome and proteome of D. reticulatus. Tick larvae are the first developmental stage to infest hosts, acquire infection and transmit pathogens that are transovarially transmitted and are exposed to extremely stressing conditions. In this study, we used a systems biology approach to get an insight into the mechanisms active in D. reticulatus unfed larvae, with special emphasis on stress response. Principal Findings The results support the use of paired end RNA sequencing and proteomics informed by transcriptomics (PIT) for the analysis of transcriptomics and proteomics data, particularly for organisms such as D. reticulatus with little sequence information available. The results showed that metabolic and cellular processes involved in protein synthesis were the most active in D. reticulatus unfed larvae, suggesting that ticks are very active during this life stage. The stress response was activated in D. reticulatus unfed larvae and a Rickettsia sp. similar to R. raoultii was identified in these ticks. Significance The activation of stress responses in D. reticulatus unfed larvae likely counteracts the negative effect of temperature and other stress conditions such as Rickettsia infection and favors tick adaptation to environmental conditions to increase tick survival. These results show mechanisms that have evolved in D. reticulatus ticks to survive under stress conditions and suggest that these mechanisms are conserved across hard tick species. Targeting some of these proteins by vaccination may increase tick susceptibility to natural stress conditions, which in turn reduce tick survival and reproduction, thus reducing tick populations and vector capacity for tick-borne pathogens.
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Affiliation(s)
- Margarita Villar
- SaBio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain
| | - Marina Popara
- SaBio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain
| | - Nieves Ayllón
- SaBio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain
| | | | - Lourdes Mateos-Hernández
- SaBio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain
| | - Ruth C. Galindo
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Marina Manrique
- Oh no sequences! Research group, Era7 Bioinformatics, Granada, Spain
| | - Raquel Tobes
- Oh no sequences! Research group, Era7 Bioinformatics, Granada, Spain
| | - José de la Fuente
- SaBio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
- * E-mail:
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396
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Abstract
The ribosome is one of the main antibiotic targets in the bacterial cell. Crystal structures of naturally produced antibiotics and their semi-synthetic derivatives bound to ribosomal particles have provided unparalleled insight into their mechanisms of action, and they are also facilitating the design of more effective antibiotics for targeting multidrug-resistant bacteria. In this Review, I discuss the recent structural insights into the mechanism of action of ribosome-targeting antibiotics and the molecular mechanisms of bacterial resistance, in addition to the approaches that are being pursued for the production of improved drugs that inhibit bacterial protein synthesis.
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397
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Cooper DA, Jha BK, Silverman RH, Hesselberth JR, Barton DJ. Ribonuclease L and metal-ion-independent endoribonuclease cleavage sites in host and viral RNAs. Nucleic Acids Res 2014; 42:5202-16. [PMID: 24500209 PMCID: PMC4005677 DOI: 10.1093/nar/gku118] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ribonuclease L (RNase L) is a metal-ion–independent endoribonuclease associated with antiviral and antibacterial defense, cancer and lifespan. Despite the biological significance of RNase L, the RNAs cleaved by this enzyme are poorly defined. In this study, we used deep sequencing methods to reveal the frequency and location of RNase L cleavage sites within host and viral RNAs. To make cDNA libraries, we exploited the 2′, 3′-cyclic phosphate at the end of RNA fragments produced by RNase L and other metal-ion–independent endoribonucleases. We optimized and validated 2′, 3′-cyclic phosphate cDNA synthesis and Illumina sequencing methods using viral RNAs cleaved with purified RNase L, viral RNAs cleaved with purified RNase A and RNA from uninfected and poliovirus-infected HeLa cells. Using these methods, we identified (i) discrete regions of hepatitis C virus and poliovirus RNA genomes that were profoundly susceptible to RNase L and other single-strand specific endoribonucleases, (ii) RNase L-dependent and RNase L-independent cleavage sites within ribosomal RNAs (rRNAs) and (iii) 2′, 3′-cyclic phosphates at the ends of 5S rRNA and U6 snRNA. Monitoring the frequency and location of metal-ion–independent endoribonuclease cleavage sites within host and viral RNAs reveals, in part, how these enzymes contribute to health and disease.
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Affiliation(s)
- Daphne A Cooper
- Department of Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA, Department of Cancer Biology, Lerner Research Institute, The Cleveland Clinic, Cleveland, OH 44195, USA, Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA and Program in Molecular Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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398
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Petrov AS, Bernier CR, Gulen B, Waterbury CC, Hershkovits E, Hsiao C, Harvey SC, Hud NV, Fox GE, Wartell RM, Williams LD. Secondary structures of rRNAs from all three domains of life. PLoS One 2014; 9:e88222. [PMID: 24505437 PMCID: PMC3914948 DOI: 10.1371/journal.pone.0088222] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 01/03/2014] [Indexed: 12/19/2022] Open
Abstract
Accurate secondary structures are important for understanding ribosomes, which are extremely large and highly complex. Using 3D structures of ribosomes as input, we have revised and corrected traditional secondary (2°) structures of rRNAs. We identify helices by specific geometric and molecular interaction criteria, not by co-variation. The structural approach allows us to incorporate non-canonical base pairs on parity with Watson-Crick base pairs. The resulting rRNA 2° structures are up-to-date and consistent with three-dimensional structures, and are information-rich. These 2° structures are relatively simple to understand and are amenable to reproduction and modification by end-users. The 2° structures made available here broadly sample the phylogenetic tree and are mapped with a variety of data related to molecular interactions and geometry, phylogeny and evolution. We have generated 2° structures for both large subunit (LSU) 23S/28S and small subunit (SSU) 16S/18S rRNAs of Escherichia coli, Thermus thermophilus, Haloarcula marismortui (LSU rRNA only), Saccharomyces cerevisiae, Drosophila melanogaster, and Homo sapiens. We provide high-resolution editable versions of the 2° structures in several file formats. For the SSU rRNA, the 2° structures use an intuitive representation of the central pseudoknot where base triples are presented as pairs of base pairs. Both LSU and SSU secondary maps are available (http://apollo.chemistry.gatech.edu/RibosomeGallery). Mapping of data onto 2° structures was performed on the RiboVision server (http://apollo.chemistry.gatech.edu/RiboVision).
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Affiliation(s)
- Anton S Petrov
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Chad R Bernier
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Burak Gulen
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Chris C Waterbury
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Eli Hershkovits
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Chiaolong Hsiao
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Stephen C Harvey
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Nicholas V Hud
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - George E Fox
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Roger M Wartell
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Loren Dean Williams
- Center for Ribosomal Origins and Evolution, Georgia Institute of Technology, Atlanta, Georgia, United States of America ; School of Chemistry and Biochemistry Georgia Institute of Technology, Atlanta, Georgia, United States of America
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399
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Khatter H, Myasnikov AG, Mastio L, Billas IML, Birck C, Stella S, Klaholz BP. Purification, characterization and crystallization of the human 80S ribosome. Nucleic Acids Res 2014; 42:e49. [PMID: 24452798 PMCID: PMC3973290 DOI: 10.1093/nar/gkt1404] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ribosomes are key macromolecular protein synthesis machineries in the cell. Human ribosomes have so far not been studied to atomic resolution because of their particularly complex structure as compared with other eukaryotic or prokaryotic ribosomes, and they are difficult to prepare to high homogeneity, which is a key requisite for high-resolution structural work. We established a purification protocol for human 80S ribosomes isolated from HeLa cells that allows obtaining large quantities of homogenous samples as characterized by biophysical methods using analytical ultracentrifugation and multiangle laser light scattering. Samples prepared under different conditions were characterized by direct single particle imaging using cryo electron microscopy, which helped optimizing the preparation protocol. From a small data set, a 3D reconstruction at subnanometric resolution was obtained showing all prominent structural features of the human ribosome, and revealing a salt concentration dependence of the presence of the exit site tRNA, which we show is critical for obtaining crystals. With these well-characterized samples first human 80S ribosome crystals were obtained from several crystallization conditions in capillaries and sitting drops, which diffract to 26 Å resolution at cryo temperatures and for which the crystallographic parameters were determined, paving the way for future high-resolution work.
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Affiliation(s)
- Heena Khatter
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France
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400
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Stanborough T, Niederhauser J, Koch B, Bergler H, Pertschy B. Ribosomal protein S3 interacts with the NF-κB inhibitor IκBα. FEBS Lett 2014; 588:659-64. [PMID: 24457201 DOI: 10.1016/j.febslet.2013.12.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/03/2013] [Accepted: 12/24/2013] [Indexed: 02/01/2023]
Abstract
Ribosomal protein S3 (RPS3) is part of nuclear, transcriptionally active and cytoplasmic inhibitory complexes containing NF-κB variant p65. We show that in resting HEK293 cells, RPS3 interacts with NF-κB inhibitor IκBα. In contrast, efficient co-precipitation of p65 with RPS3 was only achieved in the presence of ectopic IκBα. In addition, a strong in vitro interaction was observed between RPS3 and IκBα, while binding between RPS3 and p65 was very weak. Furthermore, IκBα facilitated the reconstitution of p65 and RPS3 into one complex in vitro. Our results suggest that IκBα sequesters not only p65 but also RPS3 in the cytoplasm. This would ensure maintenance of an RPS3 pool for the NF-κB pathway as well as equimolar release of RPS3 and p65 upon stimulation.
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Affiliation(s)
- Tamsyn Stanborough
- Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Johannes Niederhauser
- Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Barbara Koch
- Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Helmut Bergler
- Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Brigitte Pertschy
- Institut für Molekulare Biowissenschaften, Universität Graz, Humboldtstrasse 50, 8010 Graz, Austria.
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