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Yilmaz Demirel N, Weber M, Höfer K. Bridging the gap: RNAylation conjugates RNAs to proteins. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119826. [PMID: 39182583 DOI: 10.1016/j.bbamcr.2024.119826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 08/04/2024] [Accepted: 08/19/2024] [Indexed: 08/27/2024]
Abstract
In nature, the majority of known RNA-protein interactions are transient. Our recent study has depicted a novel mechanism known as RNAylation, which covalently links proteins and RNAs. This novel modification bridges the realms of RNA and protein modifications. This review specifically explores RNAylation catalyzed by bacteriophage T4 ADP-ribosyltransferase ModB, with a focus on its protein targets and RNA substrates in the context of Escherichia coli-bacteriophage T4 interaction. Additionally, we discuss the biological significance of RNAylation and present perspectives on RNAylation as a versatile bioconjugation strategy for RNAs and proteins.
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Affiliation(s)
- Nurseda Yilmaz Demirel
- Max-Planck-Institute for Terrestrial Microbiology and Center for Synthetic Microbiology, 35043 Marburg, Germany
| | - Moritz Weber
- Max-Planck-Institute for Terrestrial Microbiology and Center for Synthetic Microbiology, 35043 Marburg, Germany
| | - Katharina Höfer
- Max-Planck-Institute for Terrestrial Microbiology and Center for Synthetic Microbiology, 35043 Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany.
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2
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Rahman ASMZ, Syroegin EA, Novomisky Nechcoff J, Devarajan A, Polikanov YS, Cardona ST. Rationally Designed Pooled CRISPRi-Seq Uncovers an Inhibitor of Bacterial Peptidyl-tRNA Hydrolase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592284. [PMID: 38979387 PMCID: PMC11230203 DOI: 10.1101/2024.05.02.592284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Pooled knockdown libraries of essential genes are useful tools for elucidating the mechanisms of action of antibacterial compounds, a pivotal step in antibiotic discovery. However, achieving genomic coverage of antibacterial targets poses a challenge due to the uneven proliferation of knockdown mutants during pooled growth, leading to the unintended loss of important targets. To overcome this issue, we describe the construction of CIMPLE ( C RISPR i - m ediated p ooled library of e ssential genes), a rationally designed pooled knockdown library built in a model antibiotic-resistant bacteria, Burkholderia cenocepacia. By analyzing growth parameters of clonal knockdown populations of an arrayed CRISPRi library, we predicted strain depletion levels during pooled growth and adjusted mutant relative abundance, approaching genomic coverage of antibacterial targets during antibiotic exposure. We first benchmarked CIMPLE by chemical-genetic profiling of known antibacterials, then applied it to an uncharacterized bacterial growth inhibitor from a new class. CRISPRi-Seq with CIMPLE, followed by biochemical validation, revealed that the novel compound targets the peptidyl-tRNA hydrolase (Pth). Overall, CIMPLE leverages the advantages of arrayed and pooled CRISPRi libraries to uncover unexplored targets for antibiotic action. Summary Bacterial mutant libraries in which antibiotic targets are downregulated are useful tools to functionally characterize novel antimicrobials. These libraries are used for chemical-genetic profiling as target-compound interactions can be inferred by differential fitness of mutants during pooled growth. Mutants that are functionally related to the antimicrobial mode of action are usually depleted from the pool upon exposure to the drug. Although powerful, this method can fail when the unequal proliferation of mutant strains before exposure causes mutants to fall below the detection level in the library pool. To address this issue, we constructed an arrayed essential gene mutant library (EGML) in the antibiotic-resistant bacterium Burkholderia cenocepacia using CRISPR interference (CRISPRi) and analyzed the growth parameters of individual mutant strains. We then modelled depletion levels during pooled growth and used the model to rationally design an optimized CRISPR interference-mediated pooled library of essential genes (CIMPLE). By adjusting the initial inoculum of the knockdown mutants, we achieved coverage of the bacterial essential genome with mutant sensitization. We exposed CIMPLE to a recently discovered antimicrobial of a novel class and discovered it inhibits the peptidyl-tRNA hydrolase, an essential bacterial enzyme. In summary, we demonstrate the utility of CIMPLE and CRISPRi-Seq to uncover the mechanism of action of novel antimicrobial compounds. Graphical abstract
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3
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Adams JME, Moulding PB, El-Halfawy OM. Polyamine-Mediated Sensitization of Klebsiella pneumoniae to Macrolides through a Dual Mode of Action. ACS Infect Dis 2024; 10:2183-2195. [PMID: 38695481 DOI: 10.1021/acsinfecdis.4c00157] [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] [Indexed: 06/15/2024]
Abstract
Chemicals bacteria encounter at the infection site could shape their stress and antibiotic responses; such effects are typically undetected under standard lab conditions. Polyamines are small molecules typically overproduced by the host during infection and have been shown to alter bacterial stress responses. We sought to determine the effect of polyamines on the antibiotic response of Klebsiella pneumoniae, a Gram-negative priority pathogen. Interestingly, putrescine and other natural polyamines sensitized K. pneumoniae to azithromycin, a macrolide protein translation inhibitor typically used for Gram-positive bacteria. This synergy was further potentiated in the physiological buffer, bicarbonate. Chemical genomic screens suggested a dual mechanism, whereby putrescine acts at the membrane and ribosome levels. Putrescine permeabilized the outer membrane of K. pneumoniae (NPN and β-lactamase assays) and the inner membrane (Escherichia coli β-galactosidase assays). Chemically and genetically perturbing membranes led to a loss of putrescine-azithromycin synergy. Putrescine also inhibited protein synthesis in an E. coli-derived cell-free protein expression assay simultaneously monitoring transcription and translation. Profiling the putrescine-azithromycin synergy against a combinatorial array of antibiotics targeting various ribosomal sites suggested that putrescine acts as tetracyclines targeting the 30S ribosomal acceptor site. Next, exploiting the natural polyamine-azithromycin synergy, we screened a polyamine analogue library for azithromycin adjuvants, discovering four azithromycin synergists with activity starting from the low micromolar range and mechanisms similar to putrescine. This work sheds light on the bacterial antibiotic responses under conditions more reflective of those at the infection site and provides a new strategy to extend the macrolide spectrum to drug-resistant K. pneumoniae.
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Affiliation(s)
- Joshua M E Adams
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Peri B Moulding
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
| | - Omar M El-Halfawy
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK S4S 0A2, Canada
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt
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4
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Lejeune C, Cornu D, Sago L, Redeker V, Virolle MJ. The stringent response is strongly activated in the antibiotic producing strain, Streptomyces coelicolor. Res Microbiol 2024; 175:104177. [PMID: 38159786 DOI: 10.1016/j.resmic.2023.104177] [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: 09/19/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
S. lividans and S. coelicolor are phylogenetically closely related strains with different abilities to produce the same specialized metabolites. Previous studies revealed that the strong antibiotic producer, S. coelicolor, had a lower ability to assimilate nitrogen and phosphate than the weak producer, Streptomyces lividans, and this resulted into a lower growth rate. A comparative proteomic dataset was used to establish the consequences of these nutritional stresses on the abundance of proteins of the translational apparatus of these strains, grown in low and high phosphate availability. Our study revealed that most proteins of the translational apparatus were less abundant in S. coelicolor than in S. lividans whereas it was the opposite for ET-Tu 3 and a TrmA-like methyltransferase. The expression of the latter being known to be under the positive control of the stringent response whereas that of the other ribosomal proteins is under its negative control, this indicated the occurrence of a strong activation of the stringent response in S. coelicolor. Furthermore, in S. lividans, ribosomal proteins were more abundant in phosphate proficiency than in phosphate limitation suggesting that a limitation in phosphate, that was also shown to trigger RelA expression, contributes to the induction of the stringent response.
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Affiliation(s)
- Clara Lejeune
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France.
| | - David Cornu
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France.
| | - Laila Sago
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France.
| | - Virginie Redeker
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France; Institut Francois Jacob, Molecular Imaging Center (MIRCen), Laboratory of Neurodegenerative Diseases, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Centre National de la Recherche Scientifique, Université Paris-Saclay, Fontenay-aux-Roses, France.
| | - Marie-Joelle Virolle
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France.
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5
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Aseev LV, Koledinskaya LS, Boni IV. Extraribosomal Functions of Bacterial Ribosomal Proteins-An Update, 2023. Int J Mol Sci 2024; 25:2957. [PMID: 38474204 DOI: 10.3390/ijms25052957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Ribosomal proteins (r-proteins) are abundant, highly conserved, and multifaceted cellular proteins in all domains of life. Most r-proteins have RNA-binding properties and can form protein-protein contacts. Bacterial r-proteins govern the co-transcriptional rRNA folding during ribosome assembly and participate in the formation of the ribosome functional sites, such as the mRNA-binding site, tRNA-binding sites, the peptidyl transferase center, and the protein exit tunnel. In addition to their primary role in a cell as integral components of the protein synthesis machinery, many r-proteins can function beyond the ribosome (the phenomenon known as moonlighting), acting either as individual regulatory proteins or in complexes with various cellular components. The extraribosomal activities of r-proteins have been studied over the decades. In the past decade, our understanding of r-protein functions has advanced significantly due to intensive studies on ribosomes and gene expression mechanisms not only in model bacteria like Escherichia coli or Bacillus subtilis but also in little-explored bacterial species from various phyla. The aim of this review is to update information on the multiple functions of r-proteins in bacteria.
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Affiliation(s)
- Leonid V Aseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
| | | | - Irina V Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
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6
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayake NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. Cell Rep 2023; 42:113229. [PMID: 37815915 PMCID: PMC10842194 DOI: 10.1016/j.celrep.2023.113229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/16/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023] Open
Abstract
Bacterial ribonucleoprotein bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here, we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We find 111 BR-body-enriched proteins showing that BR-bodies are more complex than previously assumed. We identify five BR-body-enriched proteins that undergo RNA-dependent phase separation in vitro with a complex network of condensate mixing. We observe that some RNP condensates co-assemble with preferred directionality, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body-associated proteins have the capacity to dissolve the condensate. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Imalka W Rathnayaka-Mudiyanselage
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | | | - Ali Hatami
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - C Bruce Mousseau
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Jamuna Vaishnav
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Michael Collins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Hadi Yassine
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Aishwarya Ghosh
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yingxi Zhu
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Matthew M Champion
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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7
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayak NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524314. [PMID: 36712072 PMCID: PMC9882336 DOI: 10.1101/2023.01.18.524314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial RNP bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We found 111 BR-body enriched proteins, including several RNA binding proteins, many of which are also recruited directly to in vitro reconstituted RNase E droplets, showing BR-bodies are more complex than previously assumed. While most BR-body enriched proteins that were tested cannot phase separate, we identified five that undergo RNA-dependent phase separation in vitro, showing other RNP condensates interface with BR-bodies. RNA degradosome protein clients are recruited more strongly to RNase E droplets than droplets of other RNP condensates, implying that client specificity is largely achieved through direct protein-protein interactions. We observe that some RNP condensates assemble with preferred directionally, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body associated proteins have the capacity to dissolve the condensate. Finally, we find that RNA dramatically stimulates the rate of RNase E phase separation in vitro, explaining the dissolution of BR-bodies after cellular mRNA depletion observed previously. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- V Nandana
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - I W Rathnayaka-Mudiyanselage
- Wayne State University, Department of Biological Sciences, Detroit, MI
- Wayne State University, Department of Chemistry, Detroit, MI
| | - N S Muthunayak
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Hatami
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - C B Mousseau
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | | | - J Vaishnav
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M Collins
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - A Gega
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | | | - H Yassine
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Ghosh
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - J S Biteen
- University of Michigan, Department of Chemistry, Ann Arbor, MI
| | - Y Zhu
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M M Champion
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | - W S Childers
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - J M Schrader
- Wayne State University, Department of Biological Sciences, Detroit, MI
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8
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Tadini L, Jeran N, Domingo G, Zambelli F, Masiero S, Calabritto A, Costantini E, Forlani S, Marsoni M, Briani F, Vannini C, Pesaresi P. Perturbation of protein homeostasis brings plastids at the crossroad between repair and dismantling. PLoS Genet 2023; 19:e1010344. [PMID: 37418499 PMCID: PMC10355426 DOI: 10.1371/journal.pgen.1010344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 05/09/2023] [Indexed: 07/09/2023] Open
Abstract
The chloroplast proteome is a dynamic mosaic of plastid- and nuclear-encoded proteins. Plastid protein homeostasis is maintained through the balance between de novo synthesis and proteolysis. Intracellular communication pathways, including the plastid-to-nucleus signalling and the protein homeostasis machinery, made of stromal chaperones and proteases, shape chloroplast proteome based on developmental and physiological needs. However, the maintenance of fully functional chloroplasts is costly and under specific stress conditions the degradation of damaged chloroplasts is essential to the maintenance of a healthy population of photosynthesising organelles while promoting nutrient redistribution to sink tissues. In this work, we have addressed this complex regulatory chloroplast-quality-control pathway by modulating the expression of two nuclear genes encoding plastid ribosomal proteins PRPS1 and PRPL4. By transcriptomics, proteomics and transmission electron microscopy analyses, we show that the increased expression of PRPS1 gene leads to chloroplast degradation and early flowering, as an escape strategy from stress. On the contrary, the overaccumulation of PRPL4 protein is kept under control by increasing the amount of plastid chaperones and components of the unfolded protein response (cpUPR) regulatory mechanism. This study advances our understanding of molecular mechanisms underlying chloroplast retrograde communication and provides new insight into cellular responses to impaired plastid protein homeostasis.
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Affiliation(s)
- Luca Tadini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Nicolaj Jeran
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Guido Domingo
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Federico Zambelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Simona Masiero
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Anna Calabritto
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Elena Costantini
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Sara Forlani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Milena Marsoni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Candida Vannini
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Paolo Pesaresi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
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9
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Giudice E, Georgeault S, Lavigne R, Pineau C, Trautwetter A, Ermel G, Blanco C, Gillet R. Purification and Characterization of Authentic 30S Ribosomal Precursors Induced by Heat Shock. Int J Mol Sci 2023; 24:ijms24043491. [PMID: 36834906 PMCID: PMC9959188 DOI: 10.3390/ijms24043491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Ribosome biogenesis is a complex and multistep process that depends on various assembly factors. To understand this process and identify the ribosome assembly intermediates, most studies have set out to delete or deplete these assembly factors. Instead, we took advantage of the impact of heat stress (45 °C) on the late stages of the biogenesis of the 30S ribosomal subunit to explore authentic precursors. Under these conditions, reduced levels of the DnaK chaperone proteins devoted to ribosome assembly lead to the transient accumulation of 21S ribosomal particles, which are 30S precursors. We constructed strains with different affinity tags on one early and one late 30S ribosomal protein and purified the 21S particles that form under heat shock. A combination of relative quantification using mass spectrometry-based proteomics and cryo-electron microscopy (cryo-EM) was then used to determine their protein contents and structures.
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Affiliation(s)
- Emmanuel Giudice
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Sylvie Georgeault
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Régis Lavigne
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Charles Pineau
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Annie Trautwetter
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Gwennola Ermel
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Carlos Blanco
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Reynald Gillet
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
- Correspondence:
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10
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Bikmullin AG, Fatkhullin B, Stetsenko A, Gabdulkhakov A, Garaeva N, Nurullina L, Klochkova E, Golubev A, Khusainov I, Trachtmann N, Blokhin D, Guskov A, Validov S, Usachev K, Yusupov M. Yet Another Similarity between Mitochondrial and Bacterial Ribosomal Small Subunit Biogenesis Obtained by Structural Characterization of RbfA from S. aureus. Int J Mol Sci 2023; 24:ijms24032118. [PMID: 36768442 PMCID: PMC9917171 DOI: 10.3390/ijms24032118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Ribosome biogenesis is a complex and highly accurate conservative process of ribosomal subunit maturation followed by association. Subunit maturation comprises sequential stages of ribosomal RNA and proteins' folding, modification and binding, with the involvement of numerous RNAses, helicases, GTPases, chaperones, RNA, protein-modifying enzymes, and assembly factors. One such assembly factor involved in bacterial 30S subunit maturation is ribosomal binding factor A (RbfA). In this study, we present the crystal (determined at 2.2 Å resolution) and NMR structures of RbfA as well as the 2.9 Å resolution cryo-EM reconstruction of the 30S-RbfA complex from Staphylococcus aureus (S. aureus). Additionally, we show that the manner of RbfA action on the small ribosomal subunit during its maturation is shared between bacteria and mitochondria. The obtained results clarify the function of RbfA in the 30S maturation process and its role in ribosome functioning in general. Furthermore, given that S. aureus is a serious human pathogen, this study provides an additional prospect to develop antimicrobials targeting bacterial pathogens.
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Affiliation(s)
- Aydar G. Bikmullin
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | - Bulat Fatkhullin
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, University of Strasbourg, 67400 Illkirch, France
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Artem Stetsenko
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, 9700 AB Groningen, The Netherlands
| | - Azat Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Natalia Garaeva
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | - Liliia Nurullina
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, University of Strasbourg, 67400 Illkirch, France
| | - Evelina Klochkova
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | - Alexander Golubev
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
| | | | - Natalie Trachtmann
- Institute of Microbiology, University of Stuttgart, D-70569 Stuttgart, Germany
| | - Dmitriy Blokhin
- NMR Laboratory, Medical Physics Department, Institute of Physics, Kazan Federal University, 420008 Kazan, Russia
| | - Albert Guskov
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, 9700 AB Groningen, The Netherlands
| | - Shamil Validov
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
- Federal Research Center “Kazan Scientific Center of Russian Academy of Sciences”, 420111 Kazan, Russia
| | - Konstantin Usachev
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
- Federal Research Center “Kazan Scientific Center of Russian Academy of Sciences”, 420111 Kazan, Russia
| | - Marat Yusupov
- Laboratory of Structural Biology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420021 Kazan, Russia
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, University of Strasbourg, 67400 Illkirch, France
- Correspondence:
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11
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Schäkermann S, Dietze P, Bandow JE. Label-Free Quantitation of Ribosomal Proteins from Bacillus subtilis for Antibiotic Research. Methods Mol Biol 2023; 2601:363-378. [PMID: 36445595 DOI: 10.1007/978-1-0716-2855-3_20] [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] [Indexed: 06/16/2023]
Abstract
Current research is focusing on ribosome heterogeneity as a response to changing environmental conditions and stresses. Altered stoichiometry and composition of ribosomal proteins as well as association of additional protein factors are mechanisms for shaping the protein expression profile or hibernating ribosomes. In this updated chapter, we present a method for the isolation of ribosomes to analyze antibiotic-induced changes in the composition of ribosomes in Bacillus subtilis or other bacteria. Ribosomes and associated proteins are isolated by ultracentrifugation, and proteins are identified and quantified using label-free mass spectrometry.
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Affiliation(s)
| | - Pascal Dietze
- Ruhr-Universität Bochum, Applied Microbiology, Bochum, Germany
| | - Julia E Bandow
- Ruhr-Universität Bochum, Applied Microbiology, Bochum, Germany
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12
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Raneri M, Alvarez-Ruiz E, Mossakovska D, Briani F. Cell-Based Fluorescent Screen Amenable to HTS to Identify Inhibitors of Bacterial Translation Initiation. Methods Mol Biol 2023; 2601:303-312. [PMID: 36445591 DOI: 10.1007/978-1-0716-2855-3_16] [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] [Indexed: 06/16/2023]
Abstract
A strategy that can be applied to the research of new molecules with antibacterial activity is to look for inhibitors of essential bacterial processes within large collections of chemically heterogeneous compounds. The implementation of this approach requires the development of assays aimed at the identification of molecules interfering with specific cell pathways that can also be used in high-throughput analysis of large chemical libraries. Here, we describe a fluorescence-based whole-cell assay in Escherichia coli devised to find inhibitors of the translation initiation pathway. Translation is a complex and essential mechanism. It involves numerous sub-steps performed by factors that are in many cases sufficiently dissimilar in bacterial and eukaryotic cells to be targetable with domain-specific drugs. As a matter of fact, translation has been proven as one of the few bacterial mechanisms pharmacologically tractable with specific antibiotics. The assay described in this updated chapter is tailored to the identification of molecules affecting the first stage of translation initiation, which is the most dissimilar step in bacteria versus mammals. The effect of the compounds under analysis is measured in living cells, thus allowing evaluation of their in vivo performance as inhibitors of translation initiation. Compared with other assays for antibacterials, the major advantages of this screen are its simplicity, high mechanism specificity, and amenability to scaling up to high-throughput analyses.
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Affiliation(s)
- Matteo Raneri
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
- Sacco S.r.l., Cadorago, Italy
| | - Emilio Alvarez-Ruiz
- GlaxoSmithKline Platform Technologies and Science, Parque Tecnologico de Madrid, Madrid, Spain
| | - Danuta Mossakovska
- GlaxoSmithKline, Stevenage, Hertfordshire, UK
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy.
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13
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Hör J, Jung J, Ðurica-Mitić S, Barquist L, Vogel J. INRI-seq enables global cell-free analysis of translation initiation and off-target effects of antisense inhibitors. Nucleic Acids Res 2022; 50:e128. [PMID: 36229039 PMCID: PMC9825163 DOI: 10.1093/nar/gkac838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/11/2022] [Accepted: 09/19/2022] [Indexed: 01/29/2023] Open
Abstract
Ribosome profiling (Ribo-seq) is a powerful method for the transcriptome-wide assessment of protein synthesis rates and the study of translational control mechanisms. Yet, Ribo-seq also has limitations. These include difficulties with the analysis of translation-modulating molecules such as antibiotics, which are often toxic or challenging to deliver into living cells. Here, we have developed in vitro Ribo-seq (INRI-seq), a cell-free method to analyze the translational landscape of a fully customizable synthetic transcriptome. Using Escherichia coli as an example, we show how INRI-seq can be used to analyze the translation initiation sites of a transcriptome of interest. We also study the global impact of direct translation inhibition by antisense peptide nucleic acid (PNA) to analyze PNA off-target effects. Overall, INRI-seq presents a scalable, sensitive method to study translation initiation in a transcriptome-wide manner without the potentially confounding effects of extracting ribosomes from living cells.
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Affiliation(s)
- Jens Hör
- Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Jakob Jung
- Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Svetlana Ðurica-Mitić
- Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Center for Infection Research (HZI), D-97080 Würzburg, Germany
- Faculty of Medicine, University of Würzburg, D-97080 Würzburg, Germany
| | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Center for Infection Research (HZI), D-97080 Würzburg, Germany
- Faculty of Medicine, University of Würzburg, D-97080 Würzburg, Germany
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14
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Zhang Y, Zhu S, Zhang C, Soliman MM, Li H, Liu X. Transcriptome analysis revealing the mechanism of soybean protein isolates and soybean peptides on Lacticaseibacillus rhamnosus Lra05. FOOD BIOSCI 2022. [DOI: 10.1016/j.fbio.2022.101681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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15
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Yan Y, Gan J, Tao Y, Okita TW, Tian L. RNA-Binding Proteins: The Key Modulator in Stress Granule Formation and Abiotic Stress Response. FRONTIERS IN PLANT SCIENCE 2022; 13:882596. [PMID: 35783947 PMCID: PMC9240754 DOI: 10.3389/fpls.2022.882596] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/04/2022] [Indexed: 05/08/2023]
Abstract
To cope with abiotic environmental stress, plants rapidly change their gene expression transcriptionally and post-transcriptionally, the latter by translational suppression of selected proteins and the assembly of cytoplasmic stress granules (SGs) that sequester mRNA transcripts. RNA-binding proteins (RBPs) are the major players in these post-transcriptional processes, which control RNA processing in the nucleus, their export from the nucleus, and overall RNA metabolism in the cytoplasm. Because of their diverse modular domain structures, various RBP types dynamically co-assemble with their targeted RNAs and interacting proteins to form SGs, a process that finely regulates stress-responsive gene expression. This review summarizes recent findings on the involvement of RBPs in adapting plants to various abiotic stresses via modulation of specific gene expression events and SG formation. The relationship of these processes with the stress hormone abscisic acid (ABA) is discussed.
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Affiliation(s)
- Yanyan Yan
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable (Ministry of Agriculture and Rural Affairs), Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China
| | - Jianghuang Gan
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable (Ministry of Agriculture and Rural Affairs), Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China
| | - Yilin Tao
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable (Ministry of Agriculture and Rural Affairs), Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China
| | - Thomas W. Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- *Correspondence: Thomas W. Okita,
| | - Li Tian
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable (Ministry of Agriculture and Rural Affairs), Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China
- Li Tian,
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16
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McIntosh M, Köchling T, Latz A, Kretz J, Heinen S, Konzer A, Klug G. A major checkpoint for protein expression in Rhodobacter sphaeroides during heat stress response occurs at the level of translation. Environ Microbiol 2021; 23:6483-6502. [PMID: 34668288 DOI: 10.1111/1462-2920.15818] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/05/2021] [Indexed: 12/24/2022]
Abstract
Temperature above the physiological optimum is a stress condition frequently faced by bacteria in their natural environments. Here, we were interested in the correlation between levels of RNA and protein under heat stress. Changes in RNA and protein levels were documented in cultures of Rhodobacter sphaeroides using RNA sequencing, quantitative mass spectrometry, western blot analysis, in vivo [35 S] methionine-labelling and plasmid-borne reporter fusions. Changes in the transcriptome were extensive. Strikingly, the proteome remained unchanged except for very few proteins. Examples include a heat shock protein, a DUF1127 protein of unknown function and sigma factor proteins from leaderless transcripts. Insight from this study indicates that R. sphaeroides responds to heat stress by producing a broad range of transcripts while simultaneously preventing translation from nearly all of them, and that this selective production of protein depends on the untranslated region of the transcript. We conclude that measurements of transcript abundance are insufficient to understand gene regulation. Rather, translation can be an important checkpoint for protein expression under certain environmental conditions. Furthermore, during heat shock, regulation at the level of transcription might represent preparation for survival in an unpredictable environment while regulation at translation ensures production of only a few proteins.
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Affiliation(s)
- Matthew McIntosh
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
| | - Thorsten Köchling
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
| | - Anna Latz
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
| | - Jonas Kretz
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
| | - Sandra Heinen
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
| | - Anne Konzer
- Biomolecular Mass Spectrometry, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Gabriele Klug
- Institute of Microbiology und Molecular Biology, IFZ, Justus-Liebig-Universität, 35292, Giessen, Germany
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17
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Srivastava A, Biswas S, Yadav S, Kumar S, Srivastava V, Mishra Y. Acute cadmium toxicity and post-stress recovery: Insights into coordinated and integrated response/recovery strategies of Anabaena sp. PCC 7120. JOURNAL OF HAZARDOUS MATERIALS 2021; 411:124822. [PMID: 33858073 DOI: 10.1016/j.jhazmat.2020.124822] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Cyanobacteria, the first photoautotrophs have remarkable adaptive capabilities against most abiotic stresses, including Cd. A model cyanobacterium, Anabaena sp. PCC 7120 has been commonly used to understand cyanobacterial plasticity under different environmental stresses. However, very few studies have focused on the acute Cd toxicity. In this context, Anabaena was subjected to 100 μM Cd for 48 h (acute Cd stress, ACdS) and then transferred into the fresh medium for post-stress recovery (PSR). We further investigated the dynamics of morpho-ultrastructure, physiology, cytosolic proteome, thylakoidal complexes, chelators, and transporters after ACdS, as well as during early (ER), mid (MR), and late (LR) phases of PSR. The findings revealed that ACdS induced intracellular Cd accumulation and ROS production, altered morpho-ultrastructure, reduced photosynthetic pigments, and affected the structural organization of PSII, which subsequently hindered photosynthetic efficiency. Anabaena responded to ACdS and recovered during PSR by reprogramming the expression pattern of proteins/genes involved in cellular defense and repair; CO2 access, Calvin-Benson cycle, glycolysis, and pentose phosphate pathway; protein biosynthesis, folding, and degradation; regulatory functions; PSI-based cyclic electron flow; Cd chelation; and efflux. These modulations occurred in an integrated and coordinated manner that facilitated Anabaena to detoxify Cd and repair ACdS-induced cellular damage.
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Affiliation(s)
- Akanksha Srivastava
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Subhankar Biswas
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Sandhya Yadav
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Sanjiv Kumar
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm 10691, Sweden
| | - Vaibhav Srivastava
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm 10691, Sweden
| | - Yogesh Mishra
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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18
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Irastortza-Olaziregi M, Amster-Choder O. Coupled Transcription-Translation in Prokaryotes: An Old Couple With New Surprises. Front Microbiol 2021; 11:624830. [PMID: 33552035 PMCID: PMC7858274 DOI: 10.3389/fmicb.2020.624830] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/18/2020] [Indexed: 01/17/2023] Open
Abstract
Coupled transcription-translation (CTT) is a hallmark of prokaryotic gene expression. CTT occurs when ribosomes associate with and initiate translation of mRNAs whose transcription has not yet concluded, therefore forming "RNAP.mRNA.ribosome" complexes. CTT is a well-documented phenomenon that is involved in important gene regulation processes, such as attenuation and operon polarity. Despite the progress in our understanding of the cellular signals that coordinate CTT, certain aspects of its molecular architecture remain controversial. Additionally, new information on the spatial segregation between the transcriptional and the translational machineries in certain species, and on the capability of certain mRNAs to localize translation-independently, questions the unanimous occurrence of CTT. Furthermore, studies where transcription and translation were artificially uncoupled showed that transcription elongation can proceed in a translation-independent manner. Here, we review studies supporting the occurrence of CTT and findings questioning its extent, as well as discuss mechanisms that may explain both coupling and uncoupling, e.g., chromosome relocation and the involvement of cis- or trans-acting elements, such as small RNAs and RNA-binding proteins. These mechanisms impact RNA localization, stability, and translation. Understanding the two options by which genes can be expressed and their consequences should shed light on a new layer of control of bacterial transcripts fate.
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Affiliation(s)
- Mikel Irastortza-Olaziregi
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
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19
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Pradal I, Esteban J, Mediero A, García-Coca M, Aguilera-Correa JJ. Contact Effect of a Methylobacterium sp. Extract on Biofilm of a Mycobacterium chimaera Strain Isolated from a 3T Heater-Cooler System. Antibiotics (Basel) 2020; 9:E474. [PMID: 32756304 PMCID: PMC7460266 DOI: 10.3390/antibiotics9080474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 11/17/2022] Open
Abstract
Mycobacterium chimaera is an opportunistic slowly growing non-tuberculous mycobacteriumof increasing importance due to the outbreak of cases associated with contaminated 3T heater-cooler device (HCD) extracorporeal membrane oxygenator (ECMO). The aim of this study was to evaluate the effect of pre-treating a surface with a Methylobacterium sp. CECT 7180 extract to inhibit the M. chimaera ECMO biofilm as well as of the treatment after different dehydration times. Surface adherence, biofilm formation and treatment effect were evaluated by estimating colony-forming units (CFU) per square centimeter and characterizing the amount of covered surface area, thickness, cell viability, and presence of intrinsic autofluorescence at different times using confocal laser scanning microscopy and image analysis. We found that exposing a surface to the Methylobacterium sp. CECT 7180 extract inhibited M. chimaera ECMO biofilm development. This effect could be result of the effect of Methylobacterium proteins, such as DNaK, trigger factor, and xanthine oxidase. In conclusion, exposing a surface to the Methylobacteriumsp. extract inhibits M. chimaera ECMO biofilm development. Furthermore, this extract could be used as a pre-treatment prior to disinfection protocols for equipment contaminated with mycobacteria after dehydration for at least 96 h.
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Affiliation(s)
- Inés Pradal
- Clinical Microbiology Department, IIS-Fundación Jiménez Díaz, UAM, 28040 Madrid, Spain
| | - Jaime Esteban
- Clinical Microbiology Department, IIS-Fundación Jiménez Díaz, UAM, 28040 Madrid, Spain
| | - Arancha Mediero
- Bone and Joint Unit, IIS-Fundación Jiménez Díaz, UAM, 28040 Madrid, Spain
| | - Marta García-Coca
- Clinical Microbiology Department, Quironsalud-Madrid University Hospital, 28223 Pozuelo de Alarcón, Spain
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20
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Azam MS, Vanderpool CK. Translation inhibition from a distance: The small RNA SgrS silences a ribosomal protein S1-dependent enhancer. Mol Microbiol 2020; 114:391-408. [PMID: 32291821 DOI: 10.1111/mmi.14514] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/26/2022]
Abstract
Many bacterial small RNAs (sRNAs) efficiently inhibit translation of target mRNAs by forming a duplex that sequesters the Shine-Dalgarno (SD) sequence or start codon and prevents formation of the translation initiation complex. There are a growing number of examples of sRNA-mRNA binding interactions distant from the SD region, but how these mediate translational regulation remains unclear. Our previous work in Escherichia coli and Salmonella identified a mechanism of translational repression of manY mRNA by the sRNA SgrS through a binding interaction upstream of the manY SD. Here, we report that SgrS forms a duplex with a uridine-rich translation-enhancing element in the manY 5' untranslated region. Notably, we show that the enhancer is ribosome-dependent and that the small ribosomal subunit protein S1 interacts with the enhancer to promote translation of manY. In collaboration with the chaperone protein Hfq, SgrS interferes with the interaction between the translation enhancer and ribosomal protein S1 to repress translation of manY mRNA. Since bacterial translation is often modulated by enhancer-like elements upstream of the SD, sRNA-mediated enhancer silencing could be a common mode of gene regulation.
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Affiliation(s)
- Muhammad S Azam
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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21
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Optimization of carbon and energy utilization through differential translational efficiency. Nat Commun 2018; 9:4474. [PMID: 30367068 PMCID: PMC6203783 DOI: 10.1038/s41467-018-06993-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 10/02/2018] [Indexed: 01/19/2023] Open
Abstract
Control of translation is vital to all species. Here we employ a multi-omics approach to decipher condition-dependent translational regulation in the model acetogen Clostridium ljungdahlii. Integration of data from cells grown autotrophically or heterotrophically revealed that pathways critical to carbon and energy metabolism are under strong translational regulation. Major pathways involved in carbon and energy metabolism are not only differentially transcribed and translated, but their translational efficiencies are differentially elevated in response to resource availability under different growth conditions. We show that translational efficiency is not static and that it changes dynamically in response to mRNA expression levels. mRNAs harboring optimized 5'-untranslated region and coding region features, have higher translational efficiencies and are significantly enriched in genes encoding carbon and energy metabolism. In contrast, mRNAs enriched in housekeeping functions harbor sub-optimal features and have lower translational efficiencies. We propose that regulation of translational efficiency is crucial for effectively controlling resource allocation in energy-deprived microorganisms.
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Abstract
ABSTRACT
Previously, leaderless mRNAs (lmRNAs) were perceived to make up only a minor fraction of the transcriptome in bacteria. However, advancements in RNA sequencing technology are uncovering vast numbers of lmRNAs, particularly in archaea,
Actinobacteria
, and extremophiles and thus underline their significance in cellular physiology and regulation. Due to the absence of conventional ribosome binding signals, lmRNA translation initiation is distinct from canonical mRNAs and can therefore be differentially regulated. The ribosome’s inherent ability to bind a 5′-terminal AUG can stabilize and protect the lmRNA from degradation or allow ribosomal loading for downstream initiation events. As a result, lmRNAs remain translationally competent during a variety of physiological conditions, allowing them to contribute to multiple regulatory mechanisms. Furthermore, the abundance of lmRNAs can increase during adverse conditions through the upregulation of lmRNA transcription from alternative promoters or by the generation of lmRNAs from canonical mRNAs cleaved by an endonucleolytic toxin. In these ways, lmRNA translation can continue during stress and contribute to regulation, illustrating their importance in the cell. Due to their presence in all domains of life and their ability to be translated by heterologous hosts, lmRNAs appear further to represent ancestral transcripts that might allow us to study the evolution of the ribosome and the translational process.
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Translation initiation in bacterial polysomes through ribosome loading on a standby site on a highly translated mRNA. Proc Natl Acad Sci U S A 2018; 115:4411-4416. [PMID: 29632209 PMCID: PMC5924895 DOI: 10.1073/pnas.1718029115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polysomes are ensembles of two or more consecutive ribosomes that translate mRNA into proteins. Adjacent ribosomes can affect the frequency with which a new ribosome is loaded into the polysome. Here we show that mRNA with a long 5′UTR can recruit the next ribosome when the genuine start site is still occupied by the leading ribosome. The second ribosome binds to the upstream standby site on the mRNA, helped by the ribosomal proteins S1/S2 of the preceding ribosome. When the translating ribosome has cleared the start codon, the consecutive ribosome can rapidly move to the translation start. Recruitment to the standby site is a mechanism to increase polysome density and to regulate the efficiency of translation in polysomes. During translation, consecutive ribosomes load on an mRNA and form a polysome. The first ribosome binds to a single-stranded mRNA region and moves toward the start codon, unwinding potential mRNA structures on the way. In contrast, the following ribosomes can dock at the start codon only when the first ribosome has vacated the initiation site. Here we show that loading of the second ribosome on a natural 38-nt-long 5′ untranslated region of lpp mRNA, which codes for the outer membrane lipoprotein from Escherichia coli, takes place before the leading ribosome has moved away from the start codon. The rapid formation of this standby complex depends on the presence of ribosomal proteins S1/S2 in the leading ribosome. The early recruitment of the second ribosome to the standby site before translation by the leading ribosome and the tight coupling between translation elongation by the first ribosome and the accommodation of the second ribosome can contribute to high translational efficiency of the lpp mRNA.
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24
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Huang KC, Lin WC, Cheng WH. Salt hypersensitive mutant 9, a nucleolar APUM23 protein, is essential for salt sensitivity in association with the ABA signaling pathway in Arabidopsis. BMC PLANT BIOLOGY 2018; 18:40. [PMID: 29490615 PMCID: PMC5831739 DOI: 10.1186/s12870-018-1255-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/21/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Although the nucleolus involves two major functions: pre-rRNA processing and ribosome biogenesis/assembly, increasing evidence indicates that it also plays important roles in response to abiotic stress. However, the possible regulatory mechanisms underlying the nucleolar proteins responsive to abiotic stress are largely unknown. High salinity is one of the major abiotic stresses, which hinders plant growth and productivity. Here, genetic screening approach was used to identify a salt hypersensitive mutant 9 (sahy9) mutant, also known as apum23, in Arabidopsis thaliana. Functional characterization of SAHY9/APUM23 through analyses of gene/protein expression profiles and metabolites was performed to decipher the possible regulatory mechanisms of the nucleolar protein SAHY9/APUM23 in response to salt stress. RESULTS Seedlings of the sahy9/apum23 mutant displayed postgermination developmental arrest and then became bleached after prolonged culture under various salt stresses. Transcriptomic and proteomic analyses of salt-treated sahy9/apum23 and wild-type seedlings revealed differential expression of genes/proteins that have similar functional categories of biological processes, primarily those involved in cellular and metabolic processes as well as abiotic and biotic stress responses. However, the consistency of differential gene expression at both the transcript and protein levels was low (~ 12%), which suggests the involvement of posttranscriptional processing during the salt response. Furthermore, the altered expression of genes and proteins mediated by SAHY9/APUM23 regarding salt sensitivity involves abscisic acid (ABA) biosynthesis and signaling, abiotic stress responses, and ribosome biogenesis-related genes. Importantly, NCED3, ABI2, PP2CA, and major ABA-responsive marker genes, such as RD20 and RD29B, were down-regulated at both the transcript and protein levels in conjunction with lower contents of ABA and changes in the expression of a subset of LEA proteins in sahy9/apum23 mutants under salt stress. Moreover, the salt hypersensitivity of the sahy9/apum23 mutant was largely rescued by the exogenous application of ABA during salt stress. CONCLUSION Our results revealed that SAHY9/APUM23 regulated the expression of ribosome biogenesis-related genes and proteins, which further affected the ribosome composition and abundance, and potential posttranscriptional regulation. The salt hypersensitivity of sahy9/apum23 is associated with the ABA-mediated signaling pathway and the downstream stress-responsive network of this pathway.
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Affiliation(s)
- Kai-Chau Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Wei-Chih Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Wan-Hsing Cheng
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
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25
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Loveland AB, Korostelev AA. Structural dynamics of protein S1 on the 70S ribosome visualized by ensemble cryo-EM. Methods 2017; 137:55-66. [PMID: 29247757 DOI: 10.1016/j.ymeth.2017.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/06/2017] [Indexed: 10/18/2022] Open
Abstract
Bacterial ribosomal protein S1 is the largest and highly flexible protein of the 30S subunit, and one of a few core ribosomal proteins for which a complete structure is lacking. S1 is thought to participate in transcription and translation. Best understood is the role of S1 in facilitating translation of mRNAs with structured 5' UTRs. Here, we present cryo-EM analyses of the 70S ribosome that reveal multiple conformations of S1. Based on comparison of several 3D maximum likelihood classification approaches in Frealign, we propose a streamlined strategy for visualizing a highly dynamic component of a large macromolecular assembly that itself exhibits high compositional and conformational heterogeneity. The resulting maps show how S1 docks at the ribosomal protein S2 near the mRNA exit channel. The globular OB-fold domains sample a wide area around the mRNA exit channel and interact with mobile tails of proteins S6 and S18. S1 also interacts with the mRNA entrance channel, where an OB-fold domain can be localized near S3 and S5. Our analyses suggest that S1 cooperates with other ribosomal proteins to form a dynamic mesh near the mRNA exit and entrance channels to modulate the binding, folding and movement of mRNA.
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Affiliation(s)
- Anna B Loveland
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA
| | - Andrei A Korostelev
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA.
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Barvík I, Rejman D, Panova N, Šanderová H, Krásný L. Non-canonical transcription initiation: the expanding universe of transcription initiating substrates. FEMS Microbiol Rev 2017; 41:131-138. [PMID: 27799279 DOI: 10.1093/femsre/fuw041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2016] [Indexed: 11/13/2022] Open
Abstract
RNA polymerase (RNAP) is the central enzyme of transcription of the genetic information from DNA into RNA. RNAP recognizes four main substrates: ATP, CTP, GTP and UTP. Experimental evidence from the past several years suggests that, besides these four NTPs, other molecules can be used to initiate transcription: (i) ribooligonucleotides (nanoRNAs) and (ii) coenzymes such as NAD+, NADH, dephospho-CoA and FAD. The presence of these molecules at the 5΄ ends of RNAs affects the properties of the RNA. Here, we discuss the expanding portfolio of molecules that can initiate transcription, their mechanism of incorporation, effects on RNA and cellular processes, and we present an outlook toward other possible initiation substrates.
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Affiliation(s)
- Ivan Barvík
- Division of Biomolecular Physics, Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v. v. i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Natalya Panova
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
| | - Hana Šanderová
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
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Chao Y, Li L, Girodat D, Förstner KU, Said N, Corcoran C, Śmiga M, Papenfort K, Reinhardt R, Wieden HJ, Luisi BF, Vogel J. In Vivo Cleavage Map Illuminates the Central Role of RNase E in Coding and Non-coding RNA Pathways. Mol Cell 2017; 65:39-51. [PMID: 28061332 PMCID: PMC5222698 DOI: 10.1016/j.molcel.2016.11.002] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/26/2016] [Accepted: 10/31/2016] [Indexed: 01/21/2023]
Abstract
Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 3' fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators.
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Affiliation(s)
- Yanjie Chao
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Lei Li
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Dylan Girodat
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Konrad U Förstner
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Nelly Said
- Laboratory of Structural Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Colin Corcoran
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Michał Śmiga
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Kai Papenfort
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Department of Biology I, Microbiology, Ludwig-Maximilians-Universität Munich, 82152 Martinsried, Germany
| | - Richard Reinhardt
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Jörg Vogel
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Helmholtz Institute for RNA-based Infection Research (HIRI), 97080 Würzburg, Germany.
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Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus. J Bacteriol 2017; 199:JB.00135-17. [PMID: 28396352 PMCID: PMC5472812 DOI: 10.1128/jb.00135-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/03/2017] [Indexed: 01/08/2023] Open
Abstract
In diverse bacterial lineages, multienzyme assemblies have evolved that are central elements of RNA metabolism and RNA-mediated regulation. The aquatic Gram-negative bacterium Caulobacter crescentus, which has been a model system for studying the bacterial cell cycle, has an RNA degradosome assembly that is formed by the endoribonuclease RNase E and includes the DEAD-box RNA helicase RhlB. Immunoprecipitations of extracts from cells expressing an epitope-tagged RNase E reveal that RhlE, another member of the DEAD-box helicase family, associates with the degradosome at temperatures below those optimum for growth. Phenotype analyses of rhlE, rhlB, and rhlE rhlB mutant strains show that RhlE is important for cell fitness at low temperature and its role may not be substituted by RhlB. Transcriptional and translational fusions of rhlE to the lacZ reporter gene and immunoblot analysis of an epitope-tagged RhlE indicate that its expression is induced upon temperature decrease, mainly through posttranscriptional regulation. RNase E pulldown assays show that other proteins, including the transcription termination factor Rho, a second DEAD-box RNA helicase, and ribosomal protein S1, also associate with the degradosome at low temperature. The results suggest that the RNA degradosome assembly can be remodeled with environmental change to alter its repertoire of helicases and other accessory proteins. IMPORTANCE DEAD-box RNA helicases are often present in the RNA degradosome complex, helping unwind secondary structures to facilitate degradation. Caulobacter crescentus is an interesting organism to investigate degradosome remodeling with change in temperature, because it thrives in freshwater bodies and withstands low temperature. In this study, we show that at low temperature, the cold-induced DEAD-box RNA helicase RhlE is recruited to the RNA degradosome, along with other helicases and the Rho protein. RhlE is essential for bacterial fitness at low temperature, and its function may not be complemented by RhlB, although RhlE is able to complement for rhlB loss. These results suggest that RhlE has a specific role in the degradosome at low temperature, potentially improving adaptation to this condition.
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Vigar JRJ, Wieden HJ. Engineering bacterial translation initiation - Do we have all the tools we need? Biochim Biophys Acta Gen Subj 2017; 1861:3060-3069. [PMID: 28315412 DOI: 10.1016/j.bbagen.2017.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/03/2017] [Accepted: 03/10/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND Reliable tools that allow precise and predictable control over gene expression are critical for the success of nearly all bioengineering applications. Translation initiation is the most regulated phase during protein biosynthesis, and is therefore a promising target for exerting control over gene expression. At the translational level, the copy number of a protein can be fine-tuned by altering the interaction between the translation initiation region of an mRNA and the ribosome. These interactions can be controlled by modulating the mRNA structure using numerous approaches, including small molecule ligands, RNAs, or RNA-binding proteins. A variety of naturally occurring regulatory elements have been repurposed, facilitating advances in synthetic gene regulation strategies. The pursuit of a comprehensive understanding of mechanisms governing translation initiation provides the framework for future engineering efforts. SCOPE OF REVIEW Here we outline state-of-the-art strategies used to predictably control translation initiation in bacteria. We also discuss current limitations in the field and future goals. MAJOR CONCLUSIONS Due to its function as the rate-determining step, initiation is the ideal point to exert effective translation regulation. Several engineering tools are currently available to rationally design the initiation characteristics of synthetic mRNAs. However, improvements are required to increase the predictability, effectiveness, and portability of these tools. GENERAL SIGNIFICANCE Predictable and reliable control over translation initiation will allow greater predictability when designing, constructing, and testing genetic circuits. The ability to build more complex circuits predictably will advance synthetic biology and contribute to our fundamental understanding of the underlying principles of these processes. "This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Justin R J Vigar
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
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Schäkermann S, Prochnow P, Bandow JE. Label-Free Quantitation of Ribosomal Proteins from Bacillus subtilis for Antibiotic Research. Methods Mol Biol 2017; 1520:291-306. [PMID: 27873260 DOI: 10.1007/978-1-4939-6634-9_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Current research is focusing on ribosome heterogeneity as a response to changing environmental conditions and stresses, such as antibiotic stress. Altered stoichiometry and composition of ribosomal proteins as well as association of additional protein factors are mechanisms for shaping the protein expression profile or hibernating ribosomes. Here, we present a method for the isolation of ribosomes to analyze antibiotic-induced changes in the composition of ribosomes in Bacillus subtilis or other bacteria. Ribosomes and associated proteins are isolated by ultracentrifugation and proteins are identified and quantified using label-free mass spectrometry.
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Affiliation(s)
- Sina Schäkermann
- Applied Microbiology, Ruhr-Universität Bochum, Universitätsstr. 150, Bochum, 44801, Germany.
| | - Pascal Prochnow
- Applied Microbiology, Ruhr-Universität Bochum, Universitätsstr. 150, Bochum, 44801, Germany
| | - Julia E Bandow
- Applied Microbiology, Ruhr-Universität Bochum, Universitätsstr. 150, Bochum, 44801, Germany
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31
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Briani F. Cell-Based Fluorescent Screen to Identify Inhibitors of Bacterial Translation Initiation. Methods Mol Biol 2017; 1520:237-245. [PMID: 27873256 DOI: 10.1007/978-1-4939-6634-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A strategy that can be applied to the research of new molecules with antibacterial activity is to look for inhibitors of essential bacterial processes within large collections of chemically heterogeneous compounds. The implementation of this approach requires the development of proper assays aimed at the identification of molecules interfering with specific cell pathways and potentially applicable to the high throughput analysis of large chemical library. Here, I describe a fluorescence-based whole-cell assay in Escherichia coli devised to find inhibitors of the translation initiation pathway. Translation is a complex and essential mechanism. It involves numerous sub-steps performed by factors that are in many cases sufficiently dissimilar in bacterial and eukaryotic cells to be targetable with domain-specific drugs. As a matter of fact, translation has been proven as one of the few bacterial mechanisms pharmacologically tractable with specific antibiotics. The assay described in this chapter is tailored to the identification of molecules affecting the first stage of translation initiation, which is the most dissimilar step in bacteria vs. mammals. The effect of the compounds under analysis is assayed in living cells, thus allowing evaluating their in vivo performance as inhibitors of translation initiation. Compared with other assays for antibacterials, the major advantages of this screen are its simplicity and high mechanism specificity.
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Affiliation(s)
- Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26/A4, 20133, Milan, Italy.
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32
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The ribosome as a missing link in prebiotic evolution II: Ribosomes encode ribosomal proteins that bind to common regions of their own mRNAs and rRNAs. J Theor Biol 2016; 397:115-27. [DOI: 10.1016/j.jtbi.2016.02.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 02/16/2016] [Accepted: 02/19/2016] [Indexed: 11/18/2022]
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Lee K, Kang H. Emerging Roles of RNA-Binding Proteins in Plant Growth, Development, and Stress Responses. Mol Cells 2016; 39:179-85. [PMID: 26831454 PMCID: PMC4794599 DOI: 10.14348/molcells.2016.2359] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 11/27/2022] Open
Abstract
Posttranscriptional regulation of RNA metabolism, including RNA processing, intron splicing, editing, RNA export, and decay, is increasingly regarded as an essential step for fine-tuning the regulation of gene expression in eukaryotes. RNA-binding proteins (RBPs) are central regulatory factors controlling posttranscriptional RNA metabolism during plant growth, development, and stress responses. Although functional roles of diverse RBPs in living organisms have been determined during the last decades, our understanding of the functional roles of RBPs in plants is lagging far behind our understanding of those in other organisms, including animals, bacteria, and viruses. However, recent functional analysis of multiple RBP family members involved in plant RNA metabolism and elucidation of the mechanistic roles of RBPs shed light on the cellular roles of diverse RBPs in growth, development, and stress responses of plants. In this review, we will discuss recent studies demonstrating the emerging roles of multiple RBP family members that play essential roles in RNA metabolism during plant growth, development, and stress responses.
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Affiliation(s)
- Kwanuk Lee
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757,
Korea
| | - Hunseung Kang
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757,
Korea
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Tadini L, Pesaresi P, Kleine T, Rossi F, Guljamow A, Sommer F, Mühlhaus T, Schroda M, Masiero S, Pribil M, Rothbart M, Hedtke B, Grimm B, Leister D. GUN1 Controls Accumulation of the Plastid Ribosomal Protein S1 at the Protein Level and Interacts with Proteins Involved in Plastid Protein Homeostasis. PLANT PHYSIOLOGY 2016; 170:1817-30. [PMID: 26823545 PMCID: PMC4775149 DOI: 10.1104/pp.15.02033] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/27/2016] [Indexed: 05/03/2023]
Abstract
Developmental or metabolic changes in chloroplasts can have profound effects on the rest of the plant cell. Such intracellular responses are associated with signals that originate in chloroplasts and convey information on their physiological status to the nucleus, which leads to large-scale changes in gene expression (retrograde signaling). A screen designed to identify components of retrograde signaling resulted in the discovery of the so-called genomes uncoupled (gun) mutants. Genetic evidence suggests that the chloroplast protein GUN1 integrates signals derived from perturbations in plastid redox state, plastid gene expression, and tetrapyrrole biosynthesis (TPB) in Arabidopsis (Arabidopsis thaliana) seedlings, exerting biogenic control of chloroplast functions. However, the molecular mechanism by which GUN1 integrates retrograde signaling in the chloroplast is unclear. Here we show that GUN1 also operates in adult plants, contributing to operational control of chloroplasts. The gun1 mutation genetically interacts with mutations of genes for the chloroplast ribosomal proteins S1 (PRPS1) and L11. Analysis of gun1 prps1 lines indicates that GUN1 controls PRPS1 accumulation at the protein level. The GUN1 protein physically interacts with proteins involved in chloroplast protein homeostasis based on coimmunoprecipitation experiments. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation experiments suggest that GUN1 might transiently interact with several TPB enzymes, including Mg-chelatase subunit D (CHLD) and two other TPB enzymes known to activate retrograde signaling. Moreover, the association of PRPS1 and CHLD with protein complexes is modulated by GUN1. These findings allow us to speculate that retrograde signaling might involve GUN1-dependent formation of protein complexes.
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Affiliation(s)
- Luca Tadini
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Paolo Pesaresi
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Tatjana Kleine
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Fabio Rossi
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Arthur Guljamow
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Frederik Sommer
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Timo Mühlhaus
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Michael Schroda
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Simona Masiero
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Mathias Pribil
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Maxi Rothbart
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Boris Hedtke
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Bernhard Grimm
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
| | - Dario Leister
- Department Biology I, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany (L.T., T.K., A.G., M.P., D.L.);Department of Biosciences, University of Milan, I-20133 Milano, Italy (P.P., F.R., S.M.);Department of Biology, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany (F.S., T.M., M.S.);Institute of Biology, Humboldt-University of Berlin, D-10115 Berlin, Germany (M.R., B.H., B.G.); andCopenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark (D.L.)
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Briani F, Carzaniga T, Dehò G. Regulation and functions of bacterial PNPase. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:241-58. [PMID: 26750178 DOI: 10.1002/wrna.1328] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/23/2015] [Accepted: 11/23/2015] [Indexed: 01/29/2023]
Abstract
Polynucleotide phosphorylase (PNPase) is an exoribonuclease that catalyzes the processive phosphorolytic degradation of RNA from the 3'-end. The enzyme catalyzes also the reverse reaction of polymerization of nucleoside diphosphates that has been implicated in the generation of heteropolymeric tails at the RNA 3'-end. The enzyme is widely conserved and plays a major role in RNA decay in both Gram-negative and Gram-positive bacteria. Moreover, it participates in maturation and quality control of stable RNA. PNPase autoregulates its own expression at post-transcriptional level through a complex mechanism that involves the endoribonuclease RNase III and translation control. The activity of PNPase is modulated in an intricate and still unclear manner by interactions with small molecules and recruitment in different multiprotein complexes. Not surprisingly, given the wide spectrum of PNPase substrates, PNPase-defective mutations in different bacterial species have pleiotropic effects and perturb the execution of genetic programs involving drastic changes in global gene expression such as biofilm formation, growth at suboptimal temperatures, and virulence.
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Affiliation(s)
- Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Thomas Carzaniga
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Gianni Dehò
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
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Colombo M, Tadini L, Peracchio C, Ferrari R, Pesaresi P. GUN1, a Jack-Of-All-Trades in Chloroplast Protein Homeostasis and Signaling. FRONTIERS IN PLANT SCIENCE 2016; 7:1427. [PMID: 27713755 PMCID: PMC5032792 DOI: 10.3389/fpls.2016.01427] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/07/2016] [Indexed: 05/04/2023]
Abstract
The GENOMES UNCOUPLED 1 (GUN1) gene has been reported to encode a chloroplast-localized pentatricopeptide-repeat protein, which acts to integrate multiple indicators of plastid developmental stage and altered plastid function, as part of chloroplast-to-nucleus retrograde communication. However, the molecular mechanisms underlying signal integration by GUN1 have remained elusive, up until the recent identification of a set of GUN1-interacting proteins, by co-immunoprecipitation and mass-spectrometric analyses, as well as protein-protein interaction assays. Here, we review the molecular functions of the different GUN1 partners and propose a major role for GUN1 as coordinator of chloroplast translation, protein import, and protein degradation. This regulatory role is implemented through proteins that, in most cases, are part of multimeric protein complexes and whose precise functions vary depending on their association states. Within this framework, GUN1 may act as a platform to promote specific functions by bringing the interacting enzymes into close proximity with their substrates, or may inhibit processes by sequestering particular pools of specific interactors. Furthermore, the interactions of GUN1 with enzymes of the tetrapyrrole biosynthesis (TPB) pathway support the involvement of tetrapyrroles as signaling molecules in retrograde communication.
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Affiliation(s)
- Monica Colombo
- Centro Ricerca e Innovazione, Fondazione Edmund MachSan Michele all'Adige, Italy
| | - Luca Tadini
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Carlotta Peracchio
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Roberto Ferrari
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
| | - Paolo Pesaresi
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilan, Italy
- *Correspondence: Paolo Pesaresi
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Hammarlöf DL, Bergman JM, Garmendia E, Hughes D. Turnover of mRNAs is one of the essential functions of RNase E. Mol Microbiol 2015; 98:34-45. [PMID: 26094815 DOI: 10.1111/mmi.13100] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2015] [Indexed: 11/28/2022]
Abstract
RNase E is an essential bacterial endoribonuclease with a central role in processing tRNAs and rRNA, and turning over mRNAs. Previous studies in strains carrying mutations in the rne structural gene have shown that tRNA processing is likely to be an essential function of RNase E but have not determined whether mRNA turnover is also an essential function. To address this we selected extragenic suppressors of temperature-sensitive mutations in rne that cause a large increase in mRNA half-life at the non-permissive temperature. Fifteen suppressors were mapped to three different loci: relBE (toxin-antitoxin system); vacB (RNase R); and rpsA (ribosomal protein S1). Each suppressor class has the potential to interact with mRNA and each restores wild-type levels of mRNA turnover but does not reverse the minor defects in tRNA and rRNA processing. RelE toxin is especially interesting because its only known activity is to cleave mRNAs in the ribosomal A-site. The relBE suppressor mutations increase transcription of relE, and controlled overexpression of RelE alone was sufficient to suppress the rne ts phenotype. Suppression increased turnover of some major mRNAs (tufA, ompA) but not all mRNAs. We propose that turnover of some mRNAs is one of the essential functions of RNase E.
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Affiliation(s)
- Disa L Hammarlöf
- Department of Medical Biochemistry and Microbiology, The Biomedical Center (Box 582), Uppsala University, Uppsala, SE-751 23, Sweden
| | - Jessica M Bergman
- Department of Medical Biochemistry and Microbiology, The Biomedical Center (Box 582), Uppsala University, Uppsala, SE-751 23, Sweden
| | - Eva Garmendia
- Department of Medical Biochemistry and Microbiology, The Biomedical Center (Box 582), Uppsala University, Uppsala, SE-751 23, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, The Biomedical Center (Box 582), Uppsala University, Uppsala, SE-751 23, Sweden
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Han JH, Lee K, Lee KH, Jung S, Jeon Y, Pai HS, Kang H. A nuclear-encoded chloroplast-targeted S1 RNA-binding domain protein affects chloroplast rRNA processing and is crucial for the normal growth of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:277-89. [PMID: 26031782 DOI: 10.1111/tpj.12889] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 05/05/2015] [Accepted: 05/13/2015] [Indexed: 05/22/2023]
Abstract
Despite the fact that a variety of nuclear-encoded RNA-binding proteins (RBPs) are targeted to the chloroplast and play essential roles during post-transcriptional RNA metabolism in the chloroplast, the physiological roles of the majority of chloroplast-targeted RBPs remain elusive. Here, we investigated the functional role of a nuclear-encoded S1 domain-containing RBP, designated SDP, in the growth and development of Arabidopsis thaliana. Confocal analysis of the SDP-green fluorescent protein revealed that SDP was localized to the chloroplast. The loss-of-function sdp mutant displayed retarded seed germination and pale-green phenotypes, and grew smaller than the wild-type plants. Chlorophyll a content and photosynthetic activity of the sdp mutant were much lower than those of wild-type plants, and the structures of the chloroplast and the prolamellar body were abnormal in the sdp mutant. The processing of rRNAs in the chloroplast was defective in the sdp mutant, and SDP was able to bind chloroplast 23S, 16S, 5S and 4.5S rRNAs. Notably, SDP possesses RNA chaperone activity. Transcript levels of the nuclear genes involved in chlorophyll biosynthesis were altered in the sdp mutant. Collectively, these results suggest that chloroplast-targeted SDP harboring RNA chaperone activity affects rRNA processing, chloroplast biogenesis and photosynthetic activity, which is crucial for normal growth of Arabidopsis.
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Affiliation(s)
- Ji Hoon Han
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea
| | - Kwanuk Lee
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea
| | - Kwang Ho Lee
- Department of Wood Science and Landscape Architecture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 500-757, Korea
| | - Sunyo Jung
- School of Life Sciences and Biotechnology, Kyungpook National University, Daegu, 702-701, Korea
| | - Young Jeon
- Department of Systems Biology, Yonsei University, Seoul, 120-749, Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul, 120-749, Korea
| | - Hunseung Kang
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea
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RNase III-Independent Autogenous Regulation of Escherichia coli Polynucleotide Phosphorylase via Translational Repression. J Bacteriol 2015; 197:1931-8. [PMID: 25825432 DOI: 10.1128/jb.00105-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 03/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The complex posttranscriptional regulation mechanism of the Escherichia coli pnp gene, which encodes the phosphorolytic exoribonuclease polynucleotide phosphorylase (PNPase), involves two endoribonucleases, namely, RNase III and RNase E, and PNPase itself, which thus autoregulates its own expression. The models proposed for pnp autoregulation posit that the target of PNPase is a mature pnp mRNA previously processed at its 5' end by RNase III, rather than the primary pnp transcript (RNase III-dependent models), and that PNPase activity eventually leads to pnp mRNA degradation by RNase E. However, some published data suggest that pnp expression may also be regulated through a PNPase-dependent, RNase III-independent mechanism. To address this issue, we constructed isogenic Δpnp rnc(+) and Δpnp Δrnc strains with a chromosomal pnp-lacZ translational fusion and measured β-galactosidase activity in the absence and presence of PNPase expressed by a plasmid. Our results show that PNPase also regulates its own expression via a reversible RNase III-independent pathway acting upstream from the RNase III-dependent branch. This pathway requires the PNPase RNA binding domains KH and S1 but not its phosphorolytic activity. We suggest that the RNase III-independent autoregulation of PNPase occurs at the level of translational repression, possibly by competition for pnp primary transcript between PNPase and the ribosomal protein S1. IMPORTANCE In Escherichia coli, polynucleotide phosphorylase (PNPase, encoded by pnp) posttranscriptionally regulates its own expression. The two models proposed so far posit a two-step mechanism in which RNase III, by cutting the leader region of the pnp primary transcript, creates the substrate for PNPase regulatory activity, eventually leading to pnp mRNA degradation by RNase E. In this work, we provide evidence supporting an additional pathway for PNPase autogenous regulation in which PNPase acts as a translational repressor independently of RNase III cleavage. Our data make a new contribution to the understanding of the regulatory mechanism of pnp mRNA, a process long since considered a paradigmatic example of posttranscriptional regulation at the level of mRNA stability.
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Raneri M, Sciandrone B, Briani F. A whole-cell assay for specific inhibitors of translation initiation in bacteria. ACTA ACUST UNITED AC 2015; 20:627-33. [PMID: 25586496 DOI: 10.1177/1087057114566376] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/05/2014] [Indexed: 11/15/2022]
Abstract
The bacterial translational apparatus is an ideal target for the search of new antibiotics. In fact, it performs an essential process carried out by a large number of potential subtargets for antibiotic action. Moreover, it is sufficiently different in several molecular details from the apparatus of Eukarya and Archaea to generally ensure specificity for the bacterial domain. This applies in particular to translation initiation, which is the most different step in the process. In bacteria, the 30S ribosomal subunit directly binds to the translation initiation region, a site within the messenger RNA (mRNA) 5'-untranslated region (5'-UTR). 30S binding is mediated by the interaction of both the 16S ribosomal RNA and the ribosomal protein S1 with specific regions of the mRNA 5'-UTR. An alternative, S1-independent pathway is enjoyed by leaderless mRNAs (i.e., transcripts devoid of a 5'-UTR). We have developed a simple fluorescence-based whole-cell assay in Escherichia coli to find inhibitors of the canonical S1-dependent translation initiation pathway. The assay has been set up both in a common E. coli laboratory strain and in a strain with an outer membrane permeability defect. Compared with other whole-cell assays for antibacterials, the major advantages of the screen described here are high sensitivity and specificity.
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Affiliation(s)
- Matteo Raneri
- Dipartimento di Bioscienze, Università degli Studi di Milano, Italy
| | | | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Italy
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41
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Byrgazov K, Grishkovskaya I, Arenz S, Coudevylle N, Temmel H, Wilson DN, Djinovic-Carugo K, Moll I. Structural basis for the interaction of protein S1 with the Escherichia coli ribosome. Nucleic Acids Res 2015; 43:661-73. [PMID: 25510494 PMCID: PMC4288201 DOI: 10.1093/nar/gku1314] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/21/2014] [Accepted: 12/04/2014] [Indexed: 11/19/2022] Open
Abstract
In Gram-negative bacteria, the multi-domain protein S1 is essential for translation initiation, as it recruits the mRNA and facilitates its localization in the decoding centre. In sharp contrast to its functional importance, S1 is still lacking from the high-resolution structures available for Escherichia coli and Thermus thermophilus ribosomes and thus the molecular mechanism governing the S1-ribosome interaction has still remained elusive. Here, we present the structure of the N-terminal S1 domain D1 when bound to the ribosome at atomic resolution by using a combination of NMR, X-ray crystallography and cryo-electron microscopy. Together with biochemical assays, the structure reveals that S1 is anchored to the ribosome primarily via a stabilizing π-stacking interaction within the short but conserved N-terminal segment that is flexibly connected to domain D1. This interaction is further stabilized by salt bridges involving the zinc binding pocket of protein S2. Overall, this work provides one hitherto enigmatic piece in the 'ribosome puzzle', namely the detailed molecular insight into the topology of the S1-ribosome interface. Moreover, our data suggest novel mechanisms that have the potential to modulate protein synthesis in response to environmental cues by changing the affinity of S1 for the ribosome.
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Affiliation(s)
- Konstantin Byrgazov
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
| | - Stefan Arenz
- Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Nicolas Coudevylle
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
| | - Hannes Temmel
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
| | - Daniel N Wilson
- Gene Center, Department of Biochemistry and Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia
| | - Isabella Moll
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
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42
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Sauert M, Temmel H, Moll I. Heterogeneity of the translational machinery: Variations on a common theme. Biochimie 2014; 114:39-47. [PMID: 25542647 DOI: 10.1016/j.biochi.2014.12.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/16/2014] [Indexed: 12/22/2022]
Abstract
In all organisms the universal process of protein synthesis is performed by the ribosome, a complex multi-component assembly composed of RNA and protein elements. Although ribosome heterogeneity was observed already more than 40 years ago, the ribosome is still traditionally viewed as an unchangeable entity that has to be equipped with all ribosomal components and translation factors in order to precisely accomplish all steps in protein synthesis. In the recent years this concept was challenged by several studies highlighting a broad variation in the composition of the translational machinery in response to environmental signals, which leads to its adaptation and functional specialization. Here, we summarize recent reports on the variability of the protein synthesis apparatus in diverse organisms and discuss the multiple mechanisms and possibilities that can lead to functional ribosome heterogeneity. Collectively, these results indicate that all cells are equipped with a remarkable toolbox to fine tune gene expression at the level of translation and emphasize the physiological importance of ribosome heterogeneity for the immediate implementation of environmental information.
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Affiliation(s)
- Martina Sauert
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
| | - Hannes Temmel
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
| | - Isabella Moll
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Centre for Molecular Biology, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria
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43
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Delvillani F, Sciandrone B, Peano C, Petiti L, Berens C, Georgi C, Ferrara S, Bertoni G, Pasini ME, Dehò G, Briani F. Tet-Trap, a genetic approach to the identification of bacterial RNA thermometers: application to Pseudomonas aeruginosa. RNA (NEW YORK, N.Y.) 2014; 20:1963-1976. [PMID: 25336583 PMCID: PMC4238360 DOI: 10.1261/rna.044354.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 09/10/2014] [Indexed: 06/04/2023]
Abstract
Modulation of mRNA translatability either by trans-acting factors (proteins or sRNAs) or by in cis-acting riboregulators is widespread in bacteria and controls relevant phenotypic traits. Unfortunately, global identification of post-transcriptionally regulated genes is complicated by poor structural and functional conservation of regulatory elements and by the limitations of proteomic approaches in protein quantification. We devised a genetic system for the identification of post-transcriptionally regulated genes and we applied this system to search for Pseudomonas aeruginosa RNA thermometers, a class of regulatory RNA that modulates gene translation in response to temperature changes. As P. aeruginosa is able to thrive in a broad range of environmental conditions, genes differentially expressed at 37 °C versus lower temperatures may be involved in infection and survival in the human host. We prepared a plasmid vector library with translational fusions of P. aeruginosa DNA fragments (PaDNA) inserted upstream of TIP2, a short peptide able to inactivate the Tet repressor (TetR) upon expression. The library was assayed in a streptomycin-resistant merodiploid rpsL(+)/rpsL31 Escherichia coli strain in which the dominant rpsL(+) allele, which confers streptomycin sensitivity, was repressed by TetR. PaDNA fragments conferring thermosensitive streptomycin resistance (i.e., expressing PaDNA-TIP2 fusions at 37°C, but not at 28°C) were sequenced. We identified four new putative thermosensors. Two of them were validated with conventional reporter systems in E. coli and P. aeruginosa. Interestingly, one regulates the expression of ptxS, a gene implicated in P. aeruginosa pathogenesis.
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Affiliation(s)
- Francesco Delvillani
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Barbara Sciandrone
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Clelia Peano
- Istituto di Tecnologie Biomediche, CNR, 20090 Segrate, Italy
| | - Luca Petiti
- Istituto di Tecnologie Biomediche, CNR, 20090 Segrate, Italy Doctoral Program of Molecular and Translational Medicine, Università degli Studi di Milano, 20133 Milano, Italy
| | - Christian Berens
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91052 Erlangen, Germany
| | - Christiane Georgi
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91052 Erlangen, Germany
| | - Silvia Ferrara
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Giovanni Bertoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Maria Enrica Pasini
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Gianni Dehò
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
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Duval M, Korepanov A, Fuchsbauer O, Fechter P, Haller A, Fabbretti A, Choulier L, Micura R, Klaholz BP, Romby P, Springer M, Marzi S. Escherichia coli ribosomal protein S1 unfolds structured mRNAs onto the ribosome for active translation initiation. PLoS Biol 2013; 11:e1001731. [PMID: 24339747 PMCID: PMC3858243 DOI: 10.1371/journal.pbio.1001731] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 10/25/2013] [Indexed: 11/24/2022] Open
Abstract
Regulation of translation initiation is well appropriate to adapt cell growth in response to stress and environmental changes. Many bacterial mRNAs adopt structures in their 5' untranslated regions that modulate the accessibility of the 30S ribosomal subunit. Structured mRNAs interact with the 30S in a two-step process where the docking of a folded mRNA precedes an accommodation step. Here, we used a combination of experimental approaches in vitro (kinetic of mRNA unfolding and binding experiments to analyze mRNA-protein or mRNA-ribosome complexes, toeprinting assays to follow the formation of ribosomal initiation complexes) and in vivo (genetic) to monitor the action of ribosomal protein S1 on the initiation of structured and regulated mRNAs. We demonstrate that r-protein S1 endows the 30S with an RNA chaperone activity that is essential for the docking and the unfolding of structured mRNAs, and for the correct positioning of the initiation codon inside the decoding channel. The first three OB-fold domains of S1 retain all its activities (mRNA and 30S binding, RNA melting activity) on the 30S subunit. S1 is not required for all mRNAs and acts differently on mRNAs according to the signals present at their 5' ends. This work shows that S1 confers to the ribosome dynamic properties to initiate translation of a large set of mRNAs with diverse structural features.
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Affiliation(s)
- Mélodie Duval
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Alexey Korepanov
- CNRS UPR9073, University Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Russia
| | - Olivier Fuchsbauer
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Pierre Fechter
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Andrea Haller
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold Franzens University, Innsbruck, Austria
| | - Attilio Fabbretti
- Laboratory of Genetics, Department of Biology MCA, University of Camerino, Camerino, Italy
| | - Laurence Choulier
- CNRS UMR 7213, Université de Strasbourg, Faculté de pharmacie, Illkirch, France
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold Franzens University, Innsbruck, Austria
| | - Bruno P. Klaholz
- Department of Integrated Structural Biology, Institute of Genetics and of Molecular and Cellular Biology, UMR 7104-CNRS, U964-INSERM, Illkirch, France; and Université de Strasbourg, Strasbourg, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Mathias Springer
- CNRS UPR9073, University Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
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45
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Carzaniga T, Mazzantini E, Nardini M, Regonesi ME, Greco C, Briani F, De Gioia L, Dehò G, Tortora P. A conserved loop in polynucleotide phosphorylase (PNPase) essential for both RNA and ADP/phosphate binding. Biochimie 2013; 97:49-59. [PMID: 24075876 DOI: 10.1016/j.biochi.2013.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 09/16/2013] [Indexed: 11/27/2022]
Abstract
Polynucleotide phosphorylase (PNPase) reversibly catalyzes RNA phosphorolysis and polymerization of nucleoside diphosphates. Its homotrimeric structure forms a central channel where RNA is accommodated. Each protomer core is formed by two paralogous RNase PH domains: PNPase1, whose function is largely unknown, hosts a conserved FFRR loop interacting with RNA, whereas PNPase2 bears the putative catalytic site, ∼20 Å away from the FFRR loop. To date, little is known regarding PNPase catalytic mechanism. We analyzed the kinetic properties of two Escherichia coli PNPase mutants in the FFRR loop (R79A and R80A), which exhibited a dramatic increase in Km for ADP/Pi binding, but not for poly(A), suggesting that the two residues may be essential for binding ADP and Pi. However, both mutants were severely impaired in shifting RNA electrophoretic mobility, implying that the two arginines contribute also to RNA binding. Additional interactions between RNA and other PNPase domains (such as KH and S1) may preserve the enzymatic activity in R79A and R80A mutants. Inspection of enzyme structure showed that PNPase has evolved a long-range acting hydrogen bonding network that connects the FFRR loop with the catalytic site via the F380 residue. This hypothesis was supported by mutation analysis. Phylogenetic analysis of PNPase domains and RNase PH suggests that such network is a unique feature of PNPase1 domain, which coevolved with the paralogous PNPase2 domain.
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Affiliation(s)
- Thomas Carzaniga
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan 20133, Italy.
| | - Elisa Mazzantini
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan 20126, Italy.
| | - Marco Nardini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan 20133, Italy.
| | - Maria Elena Regonesi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan 20126, Italy.
| | - Claudio Greco
- Dipartimento di Scienze dell'ambiente e del territorio e di Scienze della terra, Università degli Studi di Milano-Bicocca, Milan 20126, Italy.
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan 20133, Italy.
| | - Luca De Gioia
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan 20126, Italy.
| | - Gianni Dehò
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan 20133, Italy.
| | - Paolo Tortora
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan 20126, Italy.
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Design and optimization of short DNA sequences that can be used as 5' fusion partners for high-level expression of heterologous genes in Escherichia coli. Appl Environ Microbiol 2013; 79:6655-64. [PMID: 23974137 DOI: 10.1128/aem.01676-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The 5' terminal nucleotide sequence of a gene is often a bottleneck in recombinant protein production. The ifn-α2bS gene is poorly expressed in Escherichia coli unless a translocation signal sequence (pelB) is fused to the 5' end of the gene. A combined in silico and in vivo analysis reported here further indicates that the ifn-α2bS 5' coding sequence is suboptimal for efficient gene expression. ifn-α2bS therefore presents a suitable model gene for describing properties of 5' fusions promoting expression. We show that short DNA sequences corresponding to the 5' end of the highly expressed celB gene, whose protein product is cytosolic, can functionally replace pelB as a 5' fusion partner for efficient ifn-α2bS expression. celB fusions of various lengths (corresponding to a minimum of 8 codons) led to more than 7- and 60-fold stimulation of expression at the transcript and protein levels, respectively. Moreover, the presence of a celB-based fusion partner was found to moderately reduce the decay rate of the corresponding transcript. The 5' fusions thus appear to act by enhancing translation, and bound ribosomes may accordingly contribute to increased mRNA stability and reduced mRNA decay. However, other effects, such as altered protein stability, cannot be excluded. We also developed an experimental protocol that enabled us to identify improved variants of the celB fusion, and one of these (celBD11) could be used to additionally increase ifn-α2bS expression more than 4-fold at the protein level. Interestingly, celBD11 also stimulated greater protein production of three other medically important human genes than the wild-type celB fragment.
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Specialization from synthesis: How ribosome diversity can customize protein function. FEBS Lett 2013; 587:1189-97. [DOI: 10.1016/j.febslet.2013.02.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 11/20/2022]
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Byrgazov K, Vesper O, Moll I. Ribosome heterogeneity: another level of complexity in bacterial translation regulation. Curr Opin Microbiol 2013; 16:133-9. [PMID: 23415603 PMCID: PMC3653068 DOI: 10.1016/j.mib.2013.01.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/21/2013] [Accepted: 01/22/2013] [Indexed: 10/27/2022]
Abstract
Translation of the mRNA-encoded genetic information into proteins is catalyzed by the intricate ribonucleoprotein machine, the ribosome. Historically, the bacterial ribosome is viewed as an unchangeable entity, constantly equipped with the entire complement of RNAs and proteins. Conversely, several lines of evidence indicate the presence of functional selective ribosomal subpopulations that exhibit variations in the RNA or the protein components and modulate the translational program in response to environmental changes. Here, we summarize these findings, which raise the functional status of the ribosome from a protein synthesis machinery only to a regulatory hub that integrates environmental cues in the process of protein synthesis, thereby adding an additional level of complexity to the regulation of gene expression.
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Affiliation(s)
- Konstantin Byrgazov
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, A-1030 Vienna, Austria
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Aseev LV, Chugunov AO, Efremov RG, Boni IV. A single missense mutation in a coiled-coil domain of Escherichia coli ribosomal protein S2 confers a thermosensitive phenotype that can be suppressed by ribosomal protein S1. J Bacteriol 2013; 195:95-104. [PMID: 23104805 PMCID: PMC3536177 DOI: 10.1128/jb.01305-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 10/21/2012] [Indexed: 01/01/2023] Open
Abstract
Ribosomal protein S2 is an essential component of translation machinery, and its viable mutated variants conferring distinct phenotypes serve as a valuable tool in studying the role of S2 in translation regulation. One of a few available rpsB mutants, rpsB1, shows thermosensitivity and ensures enhanced expression of leaderless mRNAs. In this study, we identified the nature of the rpsB1 mutation. Sequencing of the rpsB1 allele revealed a G-to-A transition in the part of the rpsB gene which encodes a coiled-coil domain of S2. The resulting E132K substitution resides in a highly conserved site, TKKE, a so-called N-terminal capping box, at the beginning of the second alpha helix. The protruding coiled-coil domain of S2 is known to provide binding with 16S rRNA in the head of the 30S subunit and, in addition, to interact with a key mRNA binding protein, S1. Molecular dynamics simulations revealed a detrimental impact of the E132K mutation on the coiled-coil structure and thereby on the interactions between S2 and 16S rRNA, providing a clue for the thermosensitivity of the rpsB1 mutant. Using a strain producing a leaderless lacZ transcript from the chromosomal lac promoter, we demonstrated that not only the rpsB1 mutation generating S2/S1-deficient ribosomes but also the rpsA::IS10 mutation leading to partial deficiency in S1 alone increased translation efficiency of the leaderless mRNA by about 10-fold. Moderate overexpression of S1 relieved all these effects and, moreover, suppressed the thermosensitive phenotype of rpsB1, indicating the role of S1 as an extragenic suppressor of the E132K mutation.
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Affiliation(s)
- Leonid V Aseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
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Cold shock genes cspA and cspB from Caulobacter crescentus are posttranscriptionally regulated and important for cold adaptation. J Bacteriol 2012; 194:6507-17. [PMID: 23002229 DOI: 10.1128/jb.01422-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cold shock proteins (CSPs) are nucleic acid binding chaperones, first described as being induced to solve the problem of mRNA stabilization after temperature downshift. Caulobacter crescentus has four CSPs: CspA and CspB, which are cold induced, and CspC and CspD, which are induced only in stationary phase. In this work we have determined that the synthesis of both CspA and CspB reaches the maximum levels early in the acclimation phase. The deletion of cspA causes a decrease in growth at low temperature, whereas the strain with a deletion of cspB has a very subtle and transient cold-related growth phenotype. The cspA cspB double mutant has a slightly more severe phenotype than that of the cspA mutant, suggesting that although CspA may be more important to cold adaptation than CspB, both proteins have a role in this process. Gene expression analyses were carried out using cspA and cspB regulatory fusions to the lacZ reporter gene and showed that both genes are regulated at the transcriptional and posttranscriptional levels. Deletion mapping of the long 5'-untranslated region (5'-UTR) of each gene identified a common region important for cold induction, probably via translation enhancement. In contrast to what was reported for other bacteria, these cold shock genes have no regulatory regions downstream from ATG that are important for cold induction. This work shows that the importance of CspA and CspB to C. crescentus cold adaptation, mechanisms of regulation, and pattern of expression during the acclimation phase apparently differs in many aspects from what has been described so far for other bacteria.
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