1
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Mitterer V, Hamze H, Kunowska N, Stelzl U, Henras A, Hurt E. The RNA helicase Dbp10 coordinates assembly factor association with PTC maturation during ribosome biogenesis. Nucleic Acids Res 2024; 52:1975-1987. [PMID: 38113283 PMCID: PMC10899779 DOI: 10.1093/nar/gkad1206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 11/08/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023] Open
Abstract
During ribosome biogenesis a plethora of assembly factors and essential enzymes drive the unidirectional maturation of nascent pre-ribosomal subunits. The DEAD-box RNA helicase Dbp10 is suggested to restructure pre-ribosomal rRNA of the evolving peptidyl-transferase center (PTC) on nucleolar ribosomal 60S assembly intermediates. Here, we show that point mutations within conserved catalytic helicase-core motifs of Dbp10 yield a dominant-lethal growth phenotype. Such dbp10 mutants, which stably associate with pre-60S intermediates, impair pre-60S biogenesis at a nucleolar stage prior to the release of assembly factor Rrp14 and stable integration of late nucleolar factors such as Noc3. Furthermore, the binding of the GTPase Nug1 to particles isolated directly via mutant Dbp10 bait proteins is specifically inhibited. The N-terminal domain of Nug1 interacts with Dbp10 and the methyltransferase Spb1, whose pre-60S incorporation is also reduced in absence of functional Dbp10 resulting in decreased methylation of 25S rRNA nucleotide G2922. Our data suggest that Dbp10's helicase activity generates the necessary framework for assembly factor docking thereby permitting PTC rRNA methylation and the progression of pre-60S maturation.
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Affiliation(s)
- Valentin Mitterer
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Hussein Hamze
- Molecular, Cellular and Developmental Biology Unit (MCD), Center for Integrative Biology (CBI), CNRS, University of Toulouse, 31062 Toulouse, France
| | - Natalia Kunowska
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, 8010 Graz, Austria
| | - Ulrich Stelzl
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit (MCD), Center for Integrative Biology (CBI), CNRS, University of Toulouse, 31062 Toulouse, France
| | - Ed Hurt
- Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany
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2
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Fernández-Fernández J, Martín-Villanueva S, Perez-Fernandez J, de la Cruz J. The Role of Ribosomal Proteins eL15 and eL36 in the Early Steps of Yeast 60S Ribosomal Subunit Assembly. J Mol Biol 2023; 435:168321. [PMID: 37865285 DOI: 10.1016/j.jmb.2023.168321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/16/2023] [Accepted: 10/16/2023] [Indexed: 10/23/2023]
Abstract
Ribosomal proteins have important roles in maintaining the structure and function of mature ribosomes, but they also drive crucial rearrangement reactions during ribosome biogenesis. The contribution of most, but not all, ribosomal proteins to ribosome synthesis has been previously analyzed in the yeast Saccharomyces cerevisiae. Herein, we characterize the role of yeast eL15 during 60S ribosomal subunit formation. In vivo depletion of eL15 results in a shortage of 60S subunits and the appearance of half-mer polysomes. This is likely due to defective processing of the 27SA3 to the 27SBS pre-rRNA and impaired subsequent processing of both forms of 27SB pre-rRNAs to mature 25S and 5.8S rRNAs. Indeed, eL15 depletion leads to the efficient turnover of the de novo formed 27S pre-rRNAs. Additionally, depletion of eL15 blocks nucleocytoplasmic export of pre-60S particles. Moreover, we have analyzed the impact of depleting either eL15 or eL36 on the composition of early pre-60S particles, thereby revealing that the depletion of eL15 or eL36 not only affects each other's assembly into pre-60S particles but also that of neighboring ribosomal proteins, including eL8. These intermediates also lack most ribosome assembly factors required for 27SA3 and 27SB pre-rRNA processing, named A3- and B-factors, respectively. Importantly, our results recapitulate previous ones obtained upon eL8 depletion. We conclude that assembly of eL15, together with that of eL8 and eL36, is a prerequisite to shape domain I of 5.8S/25S rRNA within early pre-60S particles, through their binding to this rRNA domain and the recruitment of specific groups of assembly factors.
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Affiliation(s)
- José Fernández-Fernández
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain
| | - Jorge Perez-Fernandez
- Department of Biochemistry III, University of Regensburg, D-93051 Regensburg, Germany.
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain.
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3
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Sanghai ZA, Piwowarczyk R, Broeck AV, Klinge S. A co-transcriptional ribosome assembly checkpoint controls nascent large ribosomal subunit maturation. Nat Struct Mol Biol 2023; 30:594-599. [PMID: 37037974 DOI: 10.1038/s41594-023-00947-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/24/2023] [Indexed: 04/12/2023]
Abstract
During transcription of eukaryotic ribosomal DNA in the nucleolus, assembly checkpoints exist that guarantee the formation of stable precursors of small and large ribosomal subunits. While the formation of an early large subunit assembly checkpoint precedes the separation of small and large subunit maturation, its mechanism of action and function remain unknown. Here, we report the cryo-electron microscopy structure of the yeast co-transcriptional large ribosomal subunit assembly intermediate that serves as a checkpoint. The structure provides the mechanistic basis for how quality-control pathways are established through co-transcriptional ribosome assembly factors, that structurally interrogate, remodel and, together with ribosomal proteins, cooperatively stabilize correctly folded pre-ribosomal RNA. Our findings thus provide a molecular explanation for quality control during eukaryotic ribosome assembly in the nucleolus.
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Affiliation(s)
- Zahra A Sanghai
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
| | - Rafal Piwowarczyk
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
| | - Arnaud Vanden Broeck
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York, USA.
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4
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Dörner K, Ruggeri C, Zemp I, Kutay U. Ribosome biogenesis factors-from names to functions. EMBO J 2023; 42:e112699. [PMID: 36762427 PMCID: PMC10068337 DOI: 10.15252/embj.2022112699] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/13/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
The assembly of ribosomal subunits is a highly orchestrated process that involves a huge cohort of accessory factors. Most eukaryotic ribosome biogenesis factors were first identified by genetic screens and proteomic approaches of pre-ribosomal particles in Saccharomyces cerevisiae. Later, research on human ribosome synthesis not only demonstrated that the requirement for many of these factors is conserved in evolution, but also revealed the involvement of additional players, reflecting a more complex assembly pathway in mammalian cells. Yet, it remained a challenge for the field to assign a function to many of the identified factors and to reveal their molecular mode of action. Over the past decade, structural, biochemical, and cellular studies have largely filled this gap in knowledge and led to a detailed understanding of the molecular role that many of the players have during the stepwise process of ribosome maturation. Such detailed knowledge of the function of ribosome biogenesis factors will be key to further understand and better treat diseases linked to disturbed ribosome assembly, including ribosomopathies, as well as different types of cancer.
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Affiliation(s)
- Kerstin Dörner
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,Molecular Life Sciences Ph.D. Program, Zurich, Switzerland
| | - Chiara Ruggeri
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,RNA Biology Ph.D. Program, Zurich, Switzerland
| | - Ivo Zemp
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Ulrike Kutay
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
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5
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Khreiss A, Capeyrou R, Lebaron S, Albert B, Bohnsack K, Bohnsack M, Henry Y, Henras A, Humbert O. The DEAD-box protein Dbp6 is an ATPase and RNA annealase interacting with the peptidyl transferase center (PTC) of the ribosome. Nucleic Acids Res 2023; 51:744-764. [PMID: 36610750 PMCID: PMC9881158 DOI: 10.1093/nar/gkac1196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/21/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
Ribosomes are ribozymes, hence correct folding of the rRNAs during ribosome biogenesis is crucial to ensure catalytic activity. RNA helicases, which can modulate RNA-RNA and RNA/protein interactions, are proposed to participate in rRNA tridimensional folding. Here, we analyze the biochemical properties of Dbp6, a DEAD-box RNA helicase required for the conversion of the initial 90S pre-ribosomal particle into the first pre-60S particle. We demonstrate that in vitro, Dbp6 shows ATPase as well as annealing and clamping activities negatively regulated by ATP. Mutations in Dbp6 core motifs involved in ATP binding and ATP hydrolysis are lethal and impair Dbp6 ATPase activity but increase its RNA binding and RNA annealing activities. These data suggest that correct regulation of these activities is important for Dbp6 function in vivo. Using in vivo cross-linking (CRAC) experiments, we show that Dbp6 interacts with 25S rRNA sequences located in the 5' domain I and in the peptidyl transferase center (PTC), and also crosslinks to snoRNAs hybridizing to the immature PTC. We propose that the ATPase and RNA clamping/annealing activities of Dbp6 modulate interactions of snoRNAs with the immature PTC and/or contribute directly to the folding of this region.
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Affiliation(s)
- Ali Khreiss
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Régine Capeyrou
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Simon Lebaron
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Benjamin Albert
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany,Göttingen Center for Molecular Biosciences, Georg-August University Göttingen, 37077 Göttingen, Germany
| | - Yves Henry
- Correspondence may also be addressed to Yves Henry. Tel: +33 5 61 33 59 53; Fax: +33 5 61 33 58 86;
| | - Anthony K Henras
- Correspondence may also be addressed to Anthony Henras. Tel: +33 5 61 33 59 55; Fax: +33 5 61 33 58 86;
| | - Odile Humbert
- To whom correspondence should be addressed. Tel: +33 5 61 33 59 52; Fax: +33 5 61 33 58 86;
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6
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Cruz VE, Sekulski K, Peddada N, Sailer C, Balasubramanian S, Weirich CS, Stengel F, Erzberger JP. Sequence-specific remodeling of a topologically complex RNP substrate by Spb4. Nat Struct Mol Biol 2022; 29:1228-1238. [PMID: 36482249 PMCID: PMC10680166 DOI: 10.1038/s41594-022-00874-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/14/2022] [Indexed: 12/13/2022]
Abstract
DEAD-box ATPases are ubiquitous enzymes essential in all aspects of RNA biology. However, the limited in vitro catalytic activities described for these enzymes are at odds with their complex cellular roles, most notably in driving large-scale RNA remodeling steps during the assembly of ribonucleoproteins (RNPs). We describe cryo-EM structures of 60S ribosomal biogenesis intermediates that reveal how context-specific RNA unwinding by the DEAD-box ATPase Spb4 results in extensive, sequence-specific remodeling of rRNA secondary structure. Multiple cis and trans interactions stabilize Spb4 in a post-catalytic, high-energy intermediate that drives the organization of the three-way junction at the base of rRNA domain IV. This mechanism explains how limited strand separation by DEAD-box ATPases is leveraged to provide non-equilibrium directionality and ensure efficient and accurate RNP assembly.
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Affiliation(s)
- Victor Emmanuel Cruz
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA
| | - Kamil Sekulski
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA
| | - Nagesh Peddada
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA
| | - Carolin Sailer
- Department of Biology, University of Konstanz, Konstanz, Germany
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
- Department of Biomedical Sciences, University of Copenhagen, København, Denmark
| | - Sahana Balasubramanian
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA
- Cell Biology & Molecular Physiology Department, University of Pittsburgh, Pittsburgh, PA, USA
| | - Christine S Weirich
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA
| | - Florian Stengel
- Department of Biology, University of Konstanz, Konstanz, Germany
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Jan P Erzberger
- Department of Biophysics, UT Southwestern Medical Center - ND10.124B, Dallas, TX, USA.
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7
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Liu X, Huang H, Karbstein K. Using DMS-MaPseq to Uncover the Roles of DEAD-box Proteins in Ribosome Assembly. Methods 2022; 204:249-257. [PMID: 35550176 PMCID: PMC10152975 DOI: 10.1016/j.ymeth.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 12/20/2022] Open
Abstract
DMS (dimethylsulfate) is a time-tested chemical probe for nucleic acid secondary structure that has recently re-emerged as a powerful tool to study RNA structure and structural changes, by coupling it to high throughput sequencing techniques. This variant, termed DMS-MaPseq, allows for mapping of all RNAs in a cell at the same time. However, if an RNA adopts different structures, for example during the assembly of an RNA-protein complex, or as part of its functional cycle, then DMS-MaPseq cannot differentiate between these structures, and an ensemble average will be produced. This is especially challenging for long-lived RNAs, such as ribosomes, whose steady-state abundance far exceeds that of any assembly intermediates, rendering those inaccessible to DMS-MaPseq on total RNAs. These challenges can be overcome by purification of assembly intermediates stalled at specific assembly steps (or steps in the functional cycle), via a combination of affinity tags and mutants stalled at defined steps, and subsequent DMS probing of these intermediates. Interpretation of the differences in DMS accessibility is facilitated by additional structural information, e.g. from cryo-EM experiments, available for many functional RNAs. While this approach is generally useful for studying RNA folding or conformational changes within RNA-protein complexes, it can be particularly valuable for studying the role(s) of DEAD-box proteins, as these tend to lead to larger conformational rearrangements, often resulting from the release of an RNA-binding protein from a bound RNA. Here we provide an adaptation of the DMS-MaPseq protocol to study RNA conformational transitions during ribosome assembly, which addresses the challenges arising from the presence of many assembly intermediates, all at concentrations far below that of mature ribosomes. While this protocol was developed for the yeast S. cerevisiae, we anticipate that it should be readily transferable to other model organisms for which affinity purification has been established.
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8
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Moraleva AA, Deryabin AS, Rubtsov YP, Rubtsova MP, Dontsova OA. Eukaryotic Ribosome Biogenesis: The 40S Subunit. Acta Naturae 2022; 14:14-30. [PMID: 35441050 PMCID: PMC9013438 DOI: 10.32607/actanaturae.11540] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/02/2022] [Indexed: 11/29/2022] Open
Abstract
The formation of eukaryotic ribosomes is a sequential process of ribosomal
precursors maturation in the nucleolus, nucleoplasm, and cytoplasm. Hundreds of
ribosomal biogenesis factors ensure the accurate processing and formation of
the ribosomal RNAs’ tertiary structure, and they interact with ribosomal
proteins. Most of what we know about the ribosome assembly has been derived
from yeast cell studies, and the mechanisms of ribosome biogenesis in
eukaryotes are considered quite conservative. Although the main stages of
ribosome biogenesis are similar across different groups of eukaryotes, this
process in humans is much more complicated owing to the larger size of the
ribosomes and pre-ribosomes and the emergence of regulatory pathways that
affect their assembly and function. Many of the factors involved in the
biogenesis of human ribosomes have been identified using genome-wide screening
based on RNA interference. This review addresses the key aspects of yeast and
human ribosome biogenesis, using the 40S subunit as an example. The mechanisms
underlying these differences are still not well understood, because, unlike
yeast, there are no effective methods for characterizing pre-ribosomal
complexes in humans. Understanding the mechanisms of human ribosome assembly
would have an incidence on a growing number of genetic diseases
(ribosomopathies) caused by mutations in the genes encoding ribosomal proteins
and ribosome biogenesis factors. In addition, there is evidence that ribosome
assembly is regulated by oncogenic signaling pathways, and that defects in the
ribosome biogenesis are linked to the activation of tumor suppressors.
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Affiliation(s)
- A. A. Moraleva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - A. S. Deryabin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - Yu. P. Rubtsov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
| | - M. P. Rubtsova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991 Russia
| | - O. A. Dontsova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russia
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991 Russia
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
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9
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Mitterer V, Pertschy B. RNA folding and functions of RNA helicases in ribosome biogenesis. RNA Biol 2022; 19:781-810. [PMID: 35678541 PMCID: PMC9196750 DOI: 10.1080/15476286.2022.2079890] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Eukaryotic ribosome biogenesis involves the synthesis of ribosomal RNA (rRNA) and its stepwise folding into the unique structure present in mature ribosomes. rRNA folding starts already co-transcriptionally in the nucleolus and continues when pre-ribosomal particles further maturate in the nucleolus and upon their transit to the nucleoplasm and cytoplasm. While the approximate order of folding of rRNA subdomains is known, especially from cryo-EM structures of pre-ribosomal particles, the actual mechanisms of rRNA folding are less well understood. Both small nucleolar RNAs (snoRNAs) and proteins have been implicated in rRNA folding. snoRNAs hybridize to precursor rRNAs (pre-rRNAs) and thereby prevent premature folding of the respective rRNA elements. Ribosomal proteins (r-proteins) and ribosome assembly factors might have a similar function by binding to rRNA elements and preventing their premature folding. Besides that, a small group of ribosome assembly factors are thought to play a more active role in rRNA folding. In particular, multiple RNA helicases participate in individual ribosome assembly steps, where they are believed to coordinate RNA folding/unfolding events or the release of proteins from the rRNA. In this review, we summarize the current knowledge on mechanisms of RNA folding and on the specific function of the individual RNA helicases involved. As the yeast Saccharomyces cerevisiae is the organism in which ribosome biogenesis and the role of RNA helicases in this process is best studied, we focused our review on insights from this model organism, but also make comparisons to other organisms where applicable.
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Affiliation(s)
- Valentin Mitterer
- Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, Heidelberg, Germany
- BioTechMed-Graz, Graz, Austria
| | - Brigitte Pertschy
- BioTechMed-Graz, Graz, Austria
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, Graz, Austria
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10
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Corsaro D. Insights into Microsporidia Evolution from Early Diverging Microsporidia. EXPERIENTIA SUPPLEMENTUM (2012) 2022; 114:71-90. [PMID: 35543999 DOI: 10.1007/978-3-030-93306-7_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.
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Affiliation(s)
- Daniele Corsaro
- CHLAREAS Chlamydia Research Association, Vandoeuvre-lès-Nancy, France.
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11
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Pöll G, Pilsl M, Griesenbeck J, Tschochner H, Milkereit P. Analysis of subunit folding contribution of three yeast large ribosomal subunit proteins required for stabilisation and processing of intermediate nuclear rRNA precursors. PLoS One 2021; 16:e0252497. [PMID: 34813592 PMCID: PMC8610266 DOI: 10.1371/journal.pone.0252497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/17/2021] [Indexed: 11/19/2022] Open
Abstract
In yeast and human cells many of the ribosomal proteins (r-proteins) are required for the stabilisation and productive processing of rRNA precursors. Functional coupling of r-protein assembly with the stabilisation and maturation of subunit precursors potentially promotes the production of ribosomes with defined composition. To further decipher mechanisms of such an intrinsic quality control pathway we analysed here the contribution of three yeast large ribosomal subunit r-proteins rpL2 (uL2), rpL25 (uL23) and rpL34 (eL34) for intermediate nuclear subunit folding steps. Structure models obtained from single particle cryo-electron microscopy analyses provided evidence for specific and hierarchic effects on the stable positioning and remodelling of large ribosomal subunit domains. Based on these structural and previous biochemical data we discuss possible mechanisms of r-protein dependent hierarchic domain arrangement and the resulting impact on the stability of misassembled subunits.
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Affiliation(s)
- Gisela Pöll
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Michael Pilsl
- Structural Biochemistry Unit, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Joachim Griesenbeck
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
| | - Herbert Tschochner
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
| | - Philipp Milkereit
- Chair of Biochemistry III, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
- * E-mail: (JG); (HT); (PM)
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12
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Jaafar M, Contreras J, Dominique C, Martín-Villanueva S, Capeyrou R, Vitali P, Rodríguez-Galán O, Velasco C, Humbert O, Watkins NJ, Villalobo E, Bohnsack KE, Bohnsack MT, Henry Y, Merhi RA, de la Cruz J, Henras AK. Association of snR190 snoRNA chaperone with early pre-60S particles is regulated by the RNA helicase Dbp7 in yeast. Nat Commun 2021; 12:6153. [PMID: 34686656 PMCID: PMC8536666 DOI: 10.1038/s41467-021-26207-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 09/22/2021] [Indexed: 12/15/2022] Open
Abstract
Synthesis of eukaryotic ribosomes involves the assembly and maturation of precursor particles (pre-ribosomal particles) containing ribosomal RNA (rRNA) precursors, ribosomal proteins (RPs) and a plethora of assembly factors (AFs). Formation of the earliest precursors of the 60S ribosomal subunit (pre-60S r-particle) is among the least understood stages of ribosome biogenesis. It involves the Npa1 complex, a protein module suggested to play a key role in the early structuring of the pre-rRNA. Npa1 displays genetic interactions with the DExD-box protein Dbp7 and interacts physically with the snR190 box C/D snoRNA. We show here that snR190 functions as a snoRNA chaperone, which likely cooperates with the Npa1 complex to initiate compaction of the pre-rRNA in early pre-60S r-particles. We further show that Dbp7 regulates the dynamic base-pairing between snR190 and the pre-rRNA within the earliest pre-60S r-particles, thereby participating in structuring the peptidyl transferase center (PTC) of the large ribosomal subunit. The molecular events underlying the assembly and maturation of the early pre-60S particles during eukaryotic ribosome synthesis are not well understood. Here, the authors combine yeast genetics and biochemical experiments to characterise the functions of two important players of eukaryotic ribosome biogenesis, the box C/D snoRNP snR190 and the helicase Dbp7, which both interact. They show that the snR190 snoRNA acts as a RNA chaperone that assists the structuring of the 25S rRNA during the maturation of early pre-60S particles and that Dbp7 is important for facilitating remodeling events in the peptidyl transferase center region of the 25S rRNAs during the maturation of early pre-60S particles.
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Affiliation(s)
- Mariam Jaafar
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France.,Genomic Stability and Biotherapy (GSBT) Laboratory, Faculty of Sciences, Rafik Hariri Campus, Lebanese University, Beirut, Lebanon.,Cancer Research Center of Lyon (CRCL), 69 008, Lyon, France
| | - Julia Contreras
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Carine Dominique
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain
| | - Régine Capeyrou
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Patrice Vitali
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Carmen Velasco
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.,Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Odile Humbert
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Nicholas J Watkins
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Eduardo Villalobo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.,Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, 37073, Göttingen, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, 37073, Göttingen, Germany.,Göttingen Center for Molecular Biosciences, Georg-August University Göttingen, 37077, Göttingen, Germany
| | - Yves Henry
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Raghida Abou Merhi
- Genomic Stability and Biotherapy (GSBT) Laboratory, Faculty of Sciences, Rafik Hariri Campus, Lebanese University, Beirut, Lebanon
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.,Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France.
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13
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Aquino GRR, Hackert P, Krogh N, Pan KT, Jaafar M, Henras AK, Nielsen H, Urlaub H, Bohnsack KE, Bohnsack MT. The RNA helicase Dbp7 promotes domain V/VI compaction and stabilization of inter-domain interactions during early 60S assembly. Nat Commun 2021; 12:6152. [PMID: 34686661 PMCID: PMC8536713 DOI: 10.1038/s41467-021-26208-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 09/22/2021] [Indexed: 02/07/2023] Open
Abstract
Early pre-60S ribosomal particles are poorly characterized, highly dynamic complexes that undergo extensive rRNA folding and compaction concomitant with assembly of ribosomal proteins and exchange of assembly factors. Pre-60S particles contain numerous RNA helicases, which are likely regulators of accurate and efficient formation of appropriate rRNA structures. Here we reveal binding of the RNA helicase Dbp7 to domain V/VI of early pre-60S particles in yeast and show that in the absence of this protein, dissociation of the Npa1 scaffolding complex, release of the snR190 folding chaperone, recruitment of the A3 cluster factors and binding of the ribosomal protein uL3 are impaired. uL3 is critical for formation of the peptidyltransferase center (PTC) and is responsible for stabilizing interactions between the 5′ and 3′ ends of the 25S, an essential pre-requisite for subsequent pre-60S maturation events. Highlighting the importance of pre-ribosome remodeling by Dbp7, our data suggest that in the absence of Dbp7 or its catalytic activity, early pre-ribosomal particles are targeted for degradation. Early steps of large 60S ribosomal subunit biogenesis are not well understood. Here, the authors combine biochemical experiments with protein-RNA crosslinking and mass spectrometry to show that the RNA helicase Dbp7 is key player during early 60S ribosomal assembly. Dbp7 regulates a series of events driving compaction of domain V/VI in early pre60S ribosomal particles.
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Affiliation(s)
- Gerald Ryan R Aquino
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Philipp Hackert
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Nicolai Krogh
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N, Copenhagen, Denmark
| | - Kuan-Ting Pan
- Max Planck Institute for Biophysical Chemistry, Bioanalytical Mass Spectrometry, 37077, Göttingen, Germany.,Hematology/Oncology, Department of Medicine II, Johann Wolfgang Goethe University, 60590, Frankfurt am Main, Germany.,Frankfurt Cancer Institute, Goethe University, 60596, Frankfurt am Main, Germany
| | - Mariam Jaafar
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Anthony K Henras
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N, Copenhagen, Denmark.,Genomics Group, Faculty of Biosciences and Aquaculture, Nord University, 8049, Bodø, Norway
| | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Bioanalytical Mass Spectrometry, 37077, Göttingen, Germany.,Institute for Clinical Chemistry, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany. .,Göttingen Centre for Molecular Biosciences, Georg-August-University, Justus-von-Liebig Weg 11, 37077, Göttingen, Germany.
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14
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Knüppel R, Fenk M, Jüttner M, Ferreira-Cerca S. In Vivo RNA Chemical Footprinting Analysis in Archaea. Methods Mol Biol 2021; 2106:193-208. [PMID: 31889259 DOI: 10.1007/978-1-0716-0231-7_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
RNA structural conformation and dynamics govern the functional properties of all RNA/RNP. Accordingly, defining changes of RNA structure and dynamics in various conditions may provide detailed insight into how RNA structural properties regulate the function of RNA/RNP. Traditional chemical footprinting analysis using chemical modifiers allows to sample the dynamics and conformation landscape of diverse RNA/RNP. However, many chemical modifiers are limited in their capacity to provide unbiased information reflecting the in vivo RNA/RNP structural landscape. In the recent years, the development of selective-2'-hydroxyl acylation analyzed by primer extension (SHAPE) methodology that uses powerful new chemical modifiers has significantly improved in vitro and in vivo structural probing of secondary and tertiary interactions of diverse RNA species at the single nucleotide level.Although the original discovery of Archaea as an independent domain of life is intimately linked to the technological development of RNA analysis, our understanding of in vivo RNA structural conformation and dynamics in this domain of life remains scarce.This protocol describes the in vivo use of SHAPE chemistry in two evolutionary divergent model Archaea, Sulfolobus acidocaldarius and Haloferax volcanii.
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Affiliation(s)
- Robert Knüppel
- Department of Biochemistry III, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Martin Fenk
- Department of Biochemistry III, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Michael Jüttner
- Department of Biochemistry III, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Department of Biochemistry III, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
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15
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Marangio P, Law KYT, Sanguinetti G, Granneman S. diffBUM-HMM: a robust statistical modeling approach for detecting RNA flexibility changes in high-throughput structure probing data. Genome Biol 2021; 22:165. [PMID: 34044851 PMCID: PMC8157727 DOI: 10.1186/s13059-021-02379-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 05/10/2021] [Indexed: 11/21/2022] Open
Abstract
Advancing RNA structural probing techniques with next-generation sequencing has generated demands for complementary computational tools to robustly extract RNA structural information amidst sampling noise and variability. We present diffBUM-HMM, a noise-aware model that enables accurate detection of RNA flexibility and conformational changes from high-throughput RNA structure-probing data. diffBUM-HMM is widely compatible, accounting for sampling variation and sequence coverage biases, and displays higher sensitivity than existing methods while robust against false positives. Our analyses of datasets generated with a variety of RNA probing chemistries demonstrate the value of diffBUM-HMM for quantitatively detecting RNA structural changes and RNA-binding protein binding sites.
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Affiliation(s)
- Paolo Marangio
- School of Informatics, The University of Edinburgh, Edinburgh, UK
- SISSA Data Science Excellence Department Initiative, Trieste, Italy
| | - Ka Ying Toby Law
- Centre for Synthetic and Systems Biology, The University of Edinburgh, Edinburgh, UK
| | - Guido Sanguinetti
- Centre for Synthetic and Systems Biology, The University of Edinburgh, Edinburgh, UK.
- School of Informatics, The University of Edinburgh, Edinburgh, UK.
- SISSA Data Science Excellence Department Initiative, Trieste, Italy.
| | - Sander Granneman
- Centre for Synthetic and Systems Biology, The University of Edinburgh, Edinburgh, UK.
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16
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Zhang W, Tian W, Gao Z, Wang G, Zhao H. Phylogenetic Utility of rRNA ITS2 Sequence-Structure under Functional Constraint. Int J Mol Sci 2020; 21:ijms21176395. [PMID: 32899108 PMCID: PMC7504139 DOI: 10.3390/ijms21176395] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 02/07/2023] Open
Abstract
The crucial function of the internal transcribed spacer 2 (ITS2) region in ribosome biogenesis depends on its secondary and tertiary structures. Despite rapidly evolving, ITS2 is under evolutionary constraints to maintain the specific secondary structures that provide functionality. A link between function, structure and evolution could contribute an understanding to each other and recently has created a growing point of sequence-structure phylogeny of ITS2. Here we briefly review the current knowledge of ITS2 processing in ribosome biogenesis, focusing on the conservative characteristics of ITS2 secondary structure, including structure form, structural motifs, cleavage sites, and base-pair interactions. We then review the phylogenetic implications and applications of this structure information, including structure-guiding sequence alignment, base-pair mutation model, and species distinguishing. We give the rationale for why incorporating structure information into tree construction could improve reliability and accuracy, and some perspectives of bioinformatics coding that allow for a meaningful evolutionary character to be extracted. In sum, this review of the integration of function, structure and evolution of ITS2 will expand the traditional sequence-based ITS2 phylogeny and thus contributes to the tree of life. The generality of ITS2 characteristics may also inspire phylogenetic use of other similar structural regions.
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Affiliation(s)
- Wei Zhang
- Marine College, Shandong University, Weihai 264209, China; (Z.G.); (G.W.); (H.Z.)
- Correspondence: ; Tel.: +86-631-5688-303
| | - Wen Tian
- State Key Laboratory of Ballast Water Research, Comprehensive Technical Service Center of Jiangyin Customs, Jiangyin 214440, China;
| | - Zhipeng Gao
- Marine College, Shandong University, Weihai 264209, China; (Z.G.); (G.W.); (H.Z.)
| | - Guoli Wang
- Marine College, Shandong University, Weihai 264209, China; (Z.G.); (G.W.); (H.Z.)
| | - Hong Zhao
- Marine College, Shandong University, Weihai 264209, China; (Z.G.); (G.W.); (H.Z.)
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17
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Ramos-Sáenz A, González-Álvarez D, Rodríguez-Galán O, Rodríguez-Gil A, Gaspar SG, Villalobo E, Dosil M, de la Cruz J. Pol5 is an essential ribosome biogenesis factor required for 60S ribosomal subunit maturation in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2019; 25:1561-1575. [PMID: 31413149 PMCID: PMC6795146 DOI: 10.1261/rna.072116.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
In Saccharomyces cerevisiae, more than 250 trans-acting factors are involved in the maturation of 40S and 60S ribosomal subunits. The expression of most of these factors is transcriptionally coregulated to ensure correct ribosome production under a wide variety of environmental and intracellular conditions. Here, we identified the essential nucleolar Pol5 protein as a novel trans-acting factor required for the synthesis of 60S ribosomal subunits. Pol5 weakly and/or transiently associates with early to medium pre-60S ribosomal particles. Depletion of and temperature-sensitive mutations in Pol5 result in a deficiency of 60S ribosomal subunits and accumulation of half-mer polysomes. Both processing of 27SB pre-rRNA to mature 25S rRNA and release of pre-60S ribosomal particles from the nucle(ol)us to the cytoplasm are impaired in the Pol5-depleted strain. Moreover, we identified the genes encoding ribosomal proteins uL23 and eL27A as multicopy suppressors of the slow growth of a temperature-sensitive pol5 mutant. These results suggest that Pol5 could function in ensuring the correct folding of 25S rRNA domain III; thus, favoring the correct assembly of these two ribosomal proteins at their respective binding sites into medium pre-60S ribosomal particles. Pol5 is homologous to the human tumor suppressor Myb-binding protein 1A (MYBBP1A). However, expression of MYBBP1A failed to complement the lethal phenotype of a pol5 null mutant strain though interfered with 60S ribosomal subunit biogenesis.
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Affiliation(s)
- Ana Ramos-Sáenz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Daniel González-Álvarez
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Alfonso Rodríguez-Gil
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
| | - Sonia G Gaspar
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Centro de Investigación Biomédica en Red en Cáncer (CIBERONC), CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
| | - Eduardo Villalobo
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
| | - Mercedes Dosil
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Centro de Investigación Biomédica en Red en Cáncer (CIBERONC), CSIC-Universidad de Salamanca, E-37007, Salamanca, Spain
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, E-37007, Salamanca, Spain
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012, Seville, Spain
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18
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Pillon MC, Lo YH, Stanley RE. IT'S 2 for the price of 1: Multifaceted ITS2 processing machines in RNA and DNA maintenance. DNA Repair (Amst) 2019; 81:102653. [PMID: 31324529 PMCID: PMC6764878 DOI: 10.1016/j.dnarep.2019.102653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cells utilize sophisticated RNA processing machines to ensure the quality of RNA. Many RNA processing machines have been further implicated in regulating the DNA damage response signifying a strong link between RNA processing and genome maintenance. One of the most intricate and highly regulated RNA processing pathways is the processing of the precursor ribosomal RNA (pre-rRNA), which is paramount for the production of ribosomes. Removal of the Internal Transcribed Spacer 2 (ITS2), located between the 5.8S and 25S rRNA, is one of the most complex steps of ribosome assembly. Processing of the ITS2 is initiated by the newly discovered endoribonuclease Las1, which cleaves at the C2 site within the ITS2, generating products that are further processed by the polynucleotide kinase Grc3, the 5'→3' exonuclease Rat1, and the 3'→5' RNA exosome complex. In addition to their defined roles in ITS2 processing, these critical cellular machines participate in other stages of ribosome assembly, turnover of numerous cellular RNAs, and genome maintenance. Here we summarize recent work defining the molecular mechanisms of ITS2 processing by these essential RNA processing machines and highlight their emerging roles in transcription termination, heterochromatin function, telomere maintenance, and DNA repair.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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19
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Palm D, Streit D, Shanmugam T, Weis BL, Ruprecht M, Simm S, Schleiff E. Plant-specific ribosome biogenesis factors in Arabidopsis thaliana with essential function in rRNA processing. Nucleic Acids Res 2019; 47:1880-1895. [PMID: 30576513 PMCID: PMC6393314 DOI: 10.1093/nar/gky1261] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 12/04/2018] [Accepted: 12/18/2018] [Indexed: 12/22/2022] Open
Abstract
rRNA processing and assembly of ribosomal proteins during maturation of ribosomes involve many ribosome biogenesis factors (RBFs). Recent studies identified differences in the set of RBFs in humans and yeast, and the existence of plant-specific RBFs has been proposed as well. To identify such plant-specific RBFs, we characterized T-DNA insertion mutants of 15 Arabidopsis thaliana genes encoding nuclear proteins with nucleotide binding properties that are not orthologues to yeast or human RBFs. Mutants of nine genes show an altered rRNA processing ranging from inhibition of initial 35S pre-rRNA cleavage to final maturation events like the 6S pre-rRNA processing. These phenotypes led to their annotation as 'involved in rRNA processing' - IRP. The irp mutants are either lethal or show developmental and stress related phenotypes. We identified IRPs for maturation of the plant-specific precursor 5'-5.8S and one affecting the pathway with ITS2 first cleavage of the 35S pre-rRNA transcript. Moreover, we realized that 5'-5.8S processing is essential, while a mutant causing 6S accumulation shows only a weak phenotype. Thus, we demonstrate the importance of the maturation of the plant-specific precursor 5'-5.8S for plant development as well as the occurrence of an ITS2 first cleavage pathway in fast dividing tissues.
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Affiliation(s)
- Denise Palm
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
| | - Deniz Streit
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
| | - Thiruvenkadam Shanmugam
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
| | - Benjamin L Weis
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
| | - Maike Ruprecht
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
| | - Stefan Simm
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
- Frankfurt Institute for Advanced Studies, D-60438 Frankfurt, Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max von Laue Str. 9, D-60438 Frankfurt, Germany
- Frankfurt Institute for Advanced Studies, D-60438 Frankfurt, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, D-60438 Frankfurt, Germany
- To whom correspondence should be addressed. Tel: +49 69 798 29285; Fax: +49 69 798 29286;
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20
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Espinar-Marchena F, Rodríguez-Galán O, Fernández-Fernández J, Linnemann J, de la Cruz J. Ribosomal protein L14 contributes to the early assembly of 60S ribosomal subunits in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 46:4715-4732. [PMID: 29788267 PMCID: PMC5961077 DOI: 10.1093/nar/gky123] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022] Open
Abstract
The contribution of most ribosomal proteins to ribosome synthesis has been quite well analysed in Saccharomyces cerevisiae. However, few yeast ribosomal proteins still await characterization. Herein, we show that L14, an essential 60S ribosomal protein, assembles in the nucleolus at an early stage into pre-60S particles. Depletion of L14 results in a deficit in 60S subunits and defective processing of 27SA2 and 27SA3 to 27SB pre-rRNAs. As a result, 27S pre-rRNAs are subjected to turnover and export of pre-60S particles is blocked. These phenotypes likely appear as the direct consequence of the reduced pre-60S particle association not only of L14 upon its depletion but also of a set of neighboring ribosomal proteins located at the solvent interface of 60S subunits and the adjacent region surrounding the polypeptide exit tunnel. These pre-60S intermediates also lack some essential trans-acting factors required for 27SB pre-rRNA processing but accumulate practically all factors required for processing of 27SA3 pre-rRNA. We have also analysed the functional interaction between the eukaryote-specific carboxy-terminal extensions of the neighboring L14 and L16 proteins. Our results indicate that removal of the most distal parts of these extensions cause slight translation alterations in mature 60S subunits.
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Affiliation(s)
- Francisco Espinar-Marchena
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, Seville, Spain. Avda. Manuel Siurot, E-41013 Seville, Spain
| | - Olga Rodríguez-Galán
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, Seville, Spain. Avda. Manuel Siurot, E-41013 Seville, Spain
| | - José Fernández-Fernández
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, Seville, Spain. Avda. Manuel Siurot, E-41013 Seville, Spain
| | - Jan Linnemann
- Institut für Biochemie III, Universität Regensburg, 93053, Regensburg, Germany
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, Seville, Spain. Avda. Manuel Siurot, E-41013 Seville, Spain
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21
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Abstract
RNA performs and regulates a diverse range of cellular processes, with new functional roles being uncovered at a rapid pace. Interest is growing in how these functions are linked to RNA structures that form in the complex cellular environment. A growing suite of technologies that use advances in RNA structural probes, high-throughput sequencing and new computational approaches to interrogate RNA structure at unprecedented throughput are beginning to provide insights into RNA structures at new spatial, temporal and cellular scales.
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Affiliation(s)
- Eric J Strobel
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
| | - Angela M Yu
- Tri-Institutional Training Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Julius B Lucks
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA.
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22
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Lackmann F, Belikov S, Burlacu E, Granneman S, Wieslander L. Maturation of the 90S pre-ribosome requires Mrd1 dependent U3 snoRNA and 35S pre-rRNA structural rearrangements. Nucleic Acids Res 2019; 46:3692-3706. [PMID: 29373706 PMCID: PMC5909432 DOI: 10.1093/nar/gky036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/15/2018] [Indexed: 01/25/2023] Open
Abstract
In eukaryotes, ribosome biogenesis requires folding and assembly of the precursor rRNA (pre-rRNA) with a large number of proteins and snoRNPs into huge RNA-protein complexes. In spite of intense genetic, biochemical and high-resolution cryo-EM studies in Saccharomyces cerevisiae, information about the structure of the 35S pre-rRNA is limited. To overcome this, we performed high-throughput SHAPE chemical probing on the 35S pre-rRNA within 90S pre-ribosomes. We focused our analyses on external (5′ETS) and internal (ITS1) transcribed spacers as well as the 18S rRNA region. We show that in the 35S pre-rRNA, the central pseudoknot is not formed and the central core of the 18S rRNA is in an open configuration but becomes more constrained in 20S pre-rRNA. The essential ribosome biogenesis protein Mrd1 influences the structure of the 18S rRNA region locally and is involved in organizing the central pseudoknot and surrounding structures. We demonstrate that U3 snoRNA dynamically interacts with the 35S pre-rRNA and that Mrd1 is required for disrupting U3 snoRNA base pairing interactions in the 5′ETS. We propose that the dynamic U3 snoRNA interactions and Mrd1 are essential for establishing the structure of the central core of 18S rRNA that is required for processing and 40S subunit function.
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Affiliation(s)
- Fredrik Lackmann
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Sergey Belikov
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Elena Burlacu
- Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Sander Granneman
- Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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23
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Co-Assembly of 40S and 60S Ribosomal Proteins in Early Steps of Eukaryotic Ribosome Assembly. Int J Mol Sci 2019; 20:ijms20112806. [PMID: 31181743 PMCID: PMC6600400 DOI: 10.3390/ijms20112806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/28/2019] [Accepted: 06/06/2019] [Indexed: 01/21/2023] Open
Abstract
In eukaryotes three of the four ribosomal RNA (rRNA) molecules are transcribed as a long precursor that is processed into mature rRNAs concurrently with the assembly of ribosomal subunits. However, the relative timing of association of ribosomal proteins with the ribosomal precursor particles and the cleavage of the precursor rRNA into the subunit-specific moieties is not known. To address this question, we searched for ribosomal precursors containing components from both subunits. Particles containing specific ribosomal proteins were targeted by inducing synthesis of epitope-tagged ribosomal proteins followed by pull-down with antibodies targeting the tagged protein. By identifying other ribosomal proteins and internal rRNA transcribed spacers (ITS1 and ITS2) in the immuno-purified ribosomal particles, we showed that eS7/S7 and uL4/L4 bind to nascent ribosomes prior to the separation of 40S and 60S specific segments, while uS4/S9, uL22, and eL13/L13 are bound after, or simultaneously with, the separation. Thus, the incorporation of ribosomal proteins from the two subunits begins as a co-assembly with a single rRNA molecule, but is finished as an assembly onto separate precursors for the two subunits.
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24
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Chaker-Margot M, Klinge S. Assembly and early maturation of large subunit precursors. RNA (NEW YORK, N.Y.) 2019; 25:465-471. [PMID: 30670483 PMCID: PMC6426289 DOI: 10.1261/rna.069799.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/19/2019] [Indexed: 06/09/2023]
Abstract
The eukaryotic ribosome is assembled through a complex process involving more than 200 factors. As preribosomal RNA is transcribed, assembly factors bind the nascent pre-rRNA and guide its correct folding, modification, and cleavage. While these early events in the assembly of the small ribosomal subunit have been relatively well characterized, assembly of the large subunit precursors, or pre-60S, is less well understood. Recent structures of nucleolar intermediates of large subunit assembly have shed light on the role of many early large subunit assembly factors, but how these particles emerge is still unknown. Here, we use the expression and purification of truncated pre-rRNAs to examine the initial assembly of pre-60S particles. Using this approach, we can recapitulate the early recruitment of large subunit assembly factors mainly to the domains I, II, and VI of the assembling 25S rRNA.
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MESH Headings
- Aptamers, Nucleotide/chemical synthesis
- Aptamers, Nucleotide/metabolism
- Cloning, Molecular
- Organelle Biogenesis
- Plasmids/chemistry
- Plasmids/metabolism
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosome Subunits, Large, Eukaryotic/genetics
- Ribosome Subunits, Large, Eukaryotic/metabolism
- Ribosome Subunits, Large, Eukaryotic/ultrastructure
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Staining and Labeling/methods
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Affiliation(s)
- Malik Chaker-Margot
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
- Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York 10065, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA
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25
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Choudhary K, Lai YH, Tran EJ, Aviran S. dStruct: identifying differentially reactive regions from RNA structurome profiling data. Genome Biol 2019; 20:40. [PMID: 30791935 PMCID: PMC6385470 DOI: 10.1186/s13059-019-1641-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/24/2019] [Indexed: 12/16/2022] Open
Abstract
RNA biology is revolutionized by recent developments of diverse high-throughput technologies for transcriptome-wide profiling of molecular RNA structures. RNA structurome profiling data can be used to identify differentially structured regions between groups of samples. Existing methods are limited in scope to specific technologies and/or do not account for biological variation. Here, we present dStruct which is the first broadly applicable method for differential analysis accounting for biological variation in structurome profiling data. dStruct is compatible with diverse profiling technologies, is validated with experimental data and simulations, and outperforms existing methods.
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Affiliation(s)
- Krishna Choudhary
- Department of Biomedical Engineering and Genome Center, University of California, Davis, One Shields Avenue, Davis, 95616 CA USA
| | - Yu-Hsuan Lai
- Department of Biochemistry, Purdue University, BCHM 305, 175 S. University Street, West Lafayette, 47907-2063 IN USA
| | - Elizabeth J. Tran
- Department of Biochemistry, Purdue University, BCHM 305, 175 S. University Street, West Lafayette, 47907-2063 IN USA
- Purdue University Center for Cancer Research, Purdue University, Hansen Life Sciences Research Building, Room 141, 201 S. University Street, West Lafayette, 47907-2064 IN USA
| | - Sharon Aviran
- Department of Biomedical Engineering and Genome Center, University of California, Davis, One Shields Avenue, Davis, 95616 CA USA
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26
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RNA helicases mediate structural transitions and compositional changes in pre-ribosomal complexes. Nat Commun 2018; 9:5383. [PMID: 30568249 PMCID: PMC6300602 DOI: 10.1038/s41467-018-07783-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 11/28/2018] [Indexed: 01/31/2023] Open
Abstract
Production of eukaryotic ribosomal subunits is a highly dynamic process; pre-ribosomes undergo numerous structural rearrangements that establish the architecture present in mature complexes and serve as key checkpoints, ensuring the fidelity of ribosome assembly. Using in vivo crosslinking, we here identify the pre-ribosomal binding sites of three RNA helicases. Our data support roles for Has1 in triggering release of the U14 snoRNP, a critical event during early 40S maturation, and in driving assembly of domain I of pre-60S complexes. Binding of Mak5 to domain II of pre-60S complexes promotes recruitment of the ribosomal protein Rpl10, which is necessary for subunit joining and ribosome function. Spb4 binds to a molecular hinge at the base of ES27 facilitating binding of the export factor Arx1, thereby promoting pre-60S export competence. Our data provide important insights into the driving forces behind key structural remodelling events during ribosomal subunit assembly.
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27
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Mailler E, Paillart JC, Marquet R, Smyth RP, Vivet-Boudou V. The evolution of RNA structural probing methods: From gels to next-generation sequencing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1518. [PMID: 30485688 DOI: 10.1002/wrna.1518] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/13/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023]
Abstract
RNA molecules are important players in all domains of life and the study of the relationship between their multiple flexible states and the associated biological roles has increased in recent years. For several decades, chemical and enzymatic structural probing experiments have been used to determine RNA structure. During this time, there has been a steady improvement in probing reagents and experimental methods, and today the structural biologist community has a large range of tools at its disposal to probe the secondary structure of RNAs in vitro and in cells. Early experiments used radioactive labeling and polyacrylamide gel electrophoresis as read-out methods. This was superseded by capillary electrophoresis, and more recently by next-generation sequencing. Today, powerful structural probing methods can characterize RNA structure on a genome-wide scale. In this review, we will provide an overview of RNA structural probing methodologies from a historical and technical perspective. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Methods > RNA Analyses in vitro and In Silico RNA Methods > RNA Analyses in Cells.
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Affiliation(s)
- Elodie Mailler
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Strasbourg, France
| | | | - Roland Marquet
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Strasbourg, France
| | - Redmond P Smyth
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Strasbourg, France
| | - Valerie Vivet-Boudou
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Strasbourg, France
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28
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Joret C, Capeyrou R, Belhabich-Baumas K, Plisson-Chastang C, Ghandour R, Humbert O, Fribourg S, Leulliot N, Lebaron S, Henras AK, Henry Y. The Npa1p complex chaperones the assembly of the earliest eukaryotic large ribosomal subunit precursor. PLoS Genet 2018; 14:e1007597. [PMID: 30169518 PMCID: PMC6136799 DOI: 10.1371/journal.pgen.1007597] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 09/13/2018] [Accepted: 07/30/2018] [Indexed: 11/18/2022] Open
Abstract
The early steps of the production of the large ribosomal subunit are probably the least understood stages of eukaryotic ribosome biogenesis. The first specific precursor to the yeast large ribosomal subunit, the first pre-60S particle, contains 30 assembly factors (AFs), including 8 RNA helicases. These helicases, presumed to drive conformational rearrangements, usually lack substrate specificity in vitro. The mechanisms by which they are targeted to their correct substrate within pre-ribosomal particles and their precise molecular roles remain largely unknown. We demonstrate that the Dbp6p helicase, essential for the normal accumulation of the first pre-60S pre-ribosomal particle in S. cerevisiae, associates with a complex of four AFs, namely Npa1p, Npa2p, Nop8p and Rsa3p, prior to their incorporation into the 90S pre-ribosomal particles. By tandem affinity purifications using yeast extracts depleted of one component of the complex, we show that Npa1p forms the backbone of the complex. We provide evidence that Npa1p and Npa2p directly bind Dbp6p and we demonstrate that Npa1p is essential for the insertion of the Dbp6p helicase within 90S pre-ribosomal particles. In addition, by an in vivo cross-linking analysis (CRAC), we map Npa1p rRNA binding sites on 25S rRNA adjacent to the root helices of the first and last secondary structure domains of 25S rRNA. This finding supports the notion that Npa1p and Dbp6p function in the formation and/or clustering of root helices of large subunit rRNAs which creates the core of the large ribosomal subunit RNA structure. Npa1p also crosslinks to snoRNAs involved in decoding center and peptidyl transferase center modifications and in the immediate vicinity of the binding sites of these snoRNAs on 25S rRNA. Our data suggest that the Dbp6p helicase and the Npa1p complex play key roles in the compaction of the central core of 25S rRNA and the control of snoRNA-pre-rRNA interactions. Ribosomes, the molecular machines synthesizing proteins, are composed of a small and large subunit, formed by the binding of numerous ribosomal proteins (RPs) to properly folded ribosomal RNAs (rRNAs). RP incorporation as well as processing and folding of rRNAs occur within a succession of pre-ribosomal particles. Formation of the initial pre-60S particle, the first precursor to the large ribosomal subunit, is the least understood step of ribosome biogenesis in eukaryotes. This pre-ribosomal particle contains several assembly factors (AFs), including RNA helicases believed to catalyse key conformational rearrangements. These helicases usually lack substrate specificity on their own. Here, we show that the Dbp6p helicase, a component of the first pre-60S particle and essential for its normal accumulation, associates with a complex of four AFs, including Npa1p. We demonstrate that Npa1p directly binds Dbp6p, forms the backbone of the complex and is required for the integration of Dbp6p within pre-ribosomal particles. We show that Npa1p binds to sequences forming the core of large subunit rRNAs as well as small nucleolar RNAs required for chemical modification of large subunit rRNAs. Altogether our results suggest that the Npa1p complex plays a crucial role in the chemical modification and folding of large subunit rRNAs.
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Affiliation(s)
- Clément Joret
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Régine Capeyrou
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Kamila Belhabich-Baumas
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Célia Plisson-Chastang
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Rabea Ghandour
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Odile Humbert
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Nicolas Leulliot
- Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Simon Lebaron
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail: (SL); (AKH); (YH)
| | - Anthony K. Henras
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail: (SL); (AKH); (YH)
| | - Yves Henry
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail: (SL); (AKH); (YH)
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29
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Wang D, McAteer SP, Wawszczyk AB, Russell CD, Tahoun A, Elmi A, Cockroft SL, Tollervey D, Granneman S, Tree JJ, Gally DL. An RNA-dependent mechanism for transient expression of bacterial translocation filaments. Nucleic Acids Res 2018; 46:3366-3381. [PMID: 29432565 PMCID: PMC5909449 DOI: 10.1093/nar/gky096] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/28/2018] [Accepted: 02/06/2018] [Indexed: 12/31/2022] Open
Abstract
The prokaryotic RNA chaperone Hfq mediates sRNA-mRNA interactions and plays a significant role in post-transcriptional regulation of the type III secretion (T3S) system produced by a range of Escherichia coli pathotypes. UV-crosslinking was used to map Hfq-binding under conditions that promote T3S and multiple interactions were identified within polycistronic transcripts produced from the locus of enterocyte effacement (LEE) that encodes the T3S system. The majority of Hfq binding was within the LEE5 and LEE4 operons, the latter encoding the translocon apparatus (SepL-EspADB) that is positively regulated by the RNA binding protein, CsrA. Using the identified Hfq-binding sites and a series of sRNA deletions, the sRNA Spot42 was shown to directly repress translation of LEE4 at the sepL 5' UTR. In silico and in vivo analyses of the sepL mRNA secondary structure combined with expression studies of truncates indicated that the unbound sepL mRNA is translationally inactive. Based on expression studies with site-directed mutants, an OFF-ON-OFF toggle model is proposed that results in transient translation of SepL and EspA filament assembly. Under this model, the nascent mRNA is translationally off, before being activated by CsrA, and then repressed by Hfq and Spot42.
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Affiliation(s)
- Dai Wang
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, South Xiangan Rd., Xiangan District, Xiamen, Fujian Province 361102, China
| | - Sean P McAteer
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Agata B Wawszczyk
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Clark D Russell
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Amin Tahoun
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
- Faculty of Veterinary Medicine, Kafrelsheikh University, 33516 Kafrel-Sheikh, Egypt
| | - Alex Elmi
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Scott L Cockroft
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Sander Granneman
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Jai J Tree
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, NSW, Australia
| | - David L Gally
- Division of Infection and Immunity, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
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