1
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Laalami S, Cavaiuolo M, Oberto J, Putzer H. Membrane Localization of RNase Y Is Important for Global Gene Expression in Bacillus subtilis. Int J Mol Sci 2024; 25:8537. [PMID: 39126106 PMCID: PMC11313650 DOI: 10.3390/ijms25158537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2024] [Revised: 07/27/2024] [Accepted: 07/29/2024] [Indexed: 08/12/2024] Open
Abstract
RNase Y is a key endoribonuclease that regulates global mRNA turnover and processing in Bacillus subtilis and likely many other bacteria. This enzyme is anchored to the cell membrane, creating a pseudo-compartmentalization that aligns with its role in initiating the decay of mRNAs primarily translated at the cell periphery. However, the reasons behind and the consequences of RNase Y's membrane attachment remain largely unknown. In our study, we examined a strain expressing wild-type levels of a cytoplasmic form of RNase Y from its chromosomal locus. This strain exhibits a slow-growth phenotype, similar to that of an RNase Y null mutant. Genome-wide data reveal a significant impact on the expression of hundreds of genes. While certain RNA substrates clearly depend on RNase Y's membrane attachment, others do not. We observed no correlation between mRNA stabilization in the mutant strains and the cellular location or function of the encoded proteins. Interestingly, the Y-complex, a specificity factor for RNase Y, also appears also recognize the cytoplasmic form of the enzyme, restoring wild-type levels of the corresponding transcripts. We propose that membrane attachment of RNase Y is crucial for its functional interaction with many coding and non-coding RNAs, limiting the cleavage of specific substrates, and potentially avoiding unfavorable competition with other ribonucleases like RNase J, which shares a similar evolutionarily conserved cleavage specificity.
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Affiliation(s)
- Soumaya Laalami
- Expression Génétique Microbienne, CNRS, Institut de Biologie Physico-Chimique, Université Paris Cité, 75005 Paris, France; (S.L.)
| | - Marina Cavaiuolo
- Expression Génétique Microbienne, CNRS, Institut de Biologie Physico-Chimique, Université Paris Cité, 75005 Paris, France; (S.L.)
- Laboratory for Food Safety, SBCL Unit, University Paris Est, ANSES, 94701 Maisons-Alfort, France
| | - Jacques Oberto
- Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
| | - Harald Putzer
- Expression Génétique Microbienne, CNRS, Institut de Biologie Physico-Chimique, Université Paris Cité, 75005 Paris, France; (S.L.)
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2
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König F, Svensson SL, Sharma CM. Interplay of two small RNAs fine-tunes hierarchical flagella gene expression in Campylobacter jejuni. Nat Commun 2024; 15:5240. [PMID: 38897989 PMCID: PMC11187230 DOI: 10.1038/s41467-024-48986-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 05/13/2024] [Indexed: 06/21/2024] Open
Abstract
Like for many bacteria, flagella are crucial for Campylobacter jejuni motility and virulence. Biogenesis of the flagellar machinery requires hierarchical transcription of early, middle (RpoN-dependent), and late (FliA-dependent) genes. However, little is known about post-transcriptional regulation of flagellar biogenesis by small RNAs (sRNAs). Here, we characterized two sRNAs with opposing effects on C. jejuni filament assembly and motility. We demonstrate that CJnc230 sRNA (FlmE), encoded downstream of the flagellar hook protein, is processed from the RpoN-dependent flgE mRNA by RNase III, RNase Y, and PNPase. We identify mRNAs encoding a flagella-interaction regulator and the anti-sigma factor FlgM as direct targets of CJnc230 repression. CJnc230 overexpression upregulates late genes, including the flagellin flaA, culminating in longer flagella and increased motility. In contrast, overexpression of the FliA-dependent sRNA CJnc170 (FlmR) reduces flagellar length and motility. Overall, our study demonstrates how the interplay of two sRNAs post-transcriptionally fine-tunes flagellar biogenesis through balancing of the hierarchically-expressed components.
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Affiliation(s)
- Fabian König
- University of Würzburg, Institute of Molecular Infection Biology, Department of Molecular Infection Biology II, 97080, Würzburg, Germany
| | - Sarah L Svensson
- University of Würzburg, Institute of Molecular Infection Biology, Department of Molecular Infection Biology II, 97080, Würzburg, Germany
- The Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Cynthia M Sharma
- University of Würzburg, Institute of Molecular Infection Biology, Department of Molecular Infection Biology II, 97080, Würzburg, Germany.
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3
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Wiegard JC, Damm K, Lechner M, Thölken C, Ngo S, Putzer H, Hartmann RK. Processing and decay of 6S-1 and 6S-2 RNAs in Bacillus subtilis. RNA (NEW YORK, N.Y.) 2023; 29:1481-1499. [PMID: 37369528 PMCID: PMC10578484 DOI: 10.1261/rna.079666.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023]
Abstract
Noncoding 6S RNAs regulate transcription by binding to the active site of bacterial RNA polymerase holoenzymes. Processing and decay of 6S-1 and 6S-2 RNA were investigated in Bacillus subtilis by northern blot and RNA-seq analyses using different RNase knockout strains, as well as by in vitro processing assays. For both 6S RNA paralogs, we identified a key-but mechanistically different-role of RNase J1. RNase J1 catalyzes 5'-end maturation of 6S-1 RNA, yet relatively inefficient and possibly via the enzyme's "sliding endonuclease" activity. 5'-end maturation has no detectable effect on 6S-1 RNA function, but rather regulates its decay: The generated 5'-monophosphate on matured 6S-1 RNA propels endonucleolytic cleavage in its apical loop region. The major 6S-2 RNA degradation pathway is initiated by endonucleolytic cleavage in the 5'-central bubble to trigger 5'-to-3'-exoribonucleolytic degradation of the downstream fragment by RNase J1. The four 3'-exonucleases of B. subtilis-RNase R, PNPase, YhaM, and particularly RNase PH-are involved in 3'-end trimming of both 6S RNAs, degradation of 6S-1 RNA fragments, and decay of abortive transcripts (so-called product RNAs, ∼14 nt in length) synthesized on 6S-1 RNA during outgrowth from stationary phase. In the case of the growth-retarded RNase Y deletion strain, we were unable to infer a specific role of RNase Y in 6S RNA decay. Yet, a participation of RNase Y in 6S RNA decay still remains possible, as evidence for such a function may have been obscured by overlapping substrate specificities of RNase Y, RNase J1, and RNase J2.
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Affiliation(s)
- Jana Christin Wiegard
- Philipps-Universität Marburg, Institut für Pharmazeutische Chemie, D-35037 Marburg, Germany
| | - Katrin Damm
- Philipps-Universität Marburg, Institut für Pharmazeutische Chemie, D-35037 Marburg, Germany
| | - Marcus Lechner
- Philipps-Universität Marburg, Center for Synthetic Microbiology (SYNMIKRO), Bioinformatics Core Facility, D-35032 Marburg, Germany
| | - Clemens Thölken
- Philipps-Universität Marburg, Center for Synthetic Microbiology (SYNMIKRO), Bioinformatics Core Facility, D-35032 Marburg, Germany
| | - Saravuth Ngo
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Harald Putzer
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Roland K Hartmann
- Philipps-Universität Marburg, Institut für Pharmazeutische Chemie, D-35037 Marburg, Germany
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4
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van Gestel J, Wagner A, Ackermann M. Pleiotropic hubs drive bacterial surface competition through parallel changes in colony composition and expansion. PLoS Biol 2023; 21:e3002338. [PMID: 37844064 PMCID: PMC10578586 DOI: 10.1371/journal.pbio.3002338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 09/18/2023] [Indexed: 10/18/2023] Open
Abstract
Bacteria commonly adhere to surfaces where they compete for both space and resources. Despite the importance of surface growth, it remains largely elusive how bacteria evolve on surfaces. We previously performed an evolution experiment where we evolved distinct Bacilli populations under a selective regime that favored colony spreading. In just a few weeks, colonies of Bacillus subtilis showed strongly advanced expansion rates, increasing their radius 2.5-fold relative to that of the ancestor. Here, we investigate what drives their rapid evolution by performing a uniquely detailed analysis of the evolutionary changes in colony development. We find mutations in diverse global regulators, RicT, RNAse Y, and LexA, with strikingly similar pleiotropic effects: They lower the rate of sporulation and simultaneously facilitate colony expansion by either reducing extracellular polysaccharide production or by promoting filamentous growth. Combining both high-throughput flow cytometry and gene expression profiling, we show that regulatory mutations lead to highly reproducible and parallel changes in global gene expression, affecting approximately 45% of all genes. This parallelism results from the coordinated manner by which regulators change activity both during colony development-in the transition from vegetative growth to dormancy-and over evolutionary time. This coordinated activity can however also break down, leading to evolutionary divergence. Altogether, we show how global regulators function as major pleiotropic hubs that drive rapid surface adaptation by mediating parallel changes in both colony composition and expansion, thereby massively reshaping gene expression.
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Affiliation(s)
- Jordi van Gestel
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, United States of America
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- The Santa Fe Institute, Santa Fe, New Mexico, United States of America
- Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, South Africa
| | - Martin Ackermann
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
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5
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Korobeinikova A, Laalami S, Berthy C, Putzer H. RNase Y Autoregulates Its Synthesis in Bacillus subtilis. Microorganisms 2023; 11:1374. [PMID: 37374876 DOI: 10.3390/microorganisms11061374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
The instability of messenger RNA is crucial to the control of gene expression. In Bacillus subtilis, RNase Y is the major decay-initiating endoribonuclease. Here, we show how this key enzyme regulates its own synthesis by modulating the longevity of its mRNA. Autoregulation is achieved through cleavages in two regions of the rny (RNase Y) transcript: (i) within the first ~100 nucleotides of the open reading frame, immediately inactivating the mRNA for further rounds of translation; (ii) cleavages in the rny 5' UTR, primarily within the 5'-terminal 50 nucleotides, creating entry sites for the 5' exonuclease J1 whose progression is blocked around position -15 of the rny mRNA, potentially by initiating ribosomes. This links the functional inactivation of the transcript by RNase J1 to translation efficiency, depending on the ribosome occupancy at the translation initiation site. By these mechanisms, RNase Y can initiate degradation of its own mRNA when the enzyme is not occupied with degradation of other RNAs and thus prevent its overexpression beyond the needs of RNA metabolism.
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Affiliation(s)
- Anna Korobeinikova
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, CNRS, Université Paris Cité, 75005 Paris, France
| | - Soumaya Laalami
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, CNRS, Université Paris Cité, 75005 Paris, France
| | - Clément Berthy
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, CNRS, Université Paris Cité, 75005 Paris, France
- Inovarion, 75005 Paris, France
| | - Harald Putzer
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, CNRS, Université Paris Cité, 75005 Paris, France
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6
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Abstract
Bacterial protein synthesis rates have evolved to maintain preferred stoichiometries at striking precision, from the components of protein complexes to constituents of entire pathways. Setting relative protein production rates to be well within a factor of two requires concerted tuning of transcription, RNA turnover, and translation, allowing many potential regulatory strategies to achieve the preferred output. The last decade has seen a greatly expanded capacity for precise interrogation of each step of the central dogma genome-wide. Here, we summarize how these technologies have shaped the current understanding of diverse bacterial regulatory architectures underpinning stoichiometric protein synthesis. We focus on the emerging expanded view of bacterial operons, which encode diverse primary and secondary mRNA structures for tuning protein stoichiometry. Emphasis is placed on how quantitative tuning is achieved. We discuss the challenges and open questions in the application of quantitative, genome-wide methodologies to the problem of precise protein production. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- James C Taggart
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; ,
| | - Jean-Benoît Lalanne
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; , .,Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Current affiliation: Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA;
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; ,
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7
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Benda M, Woelfel S, Faßhauer P, Gunka K, Klumpp S, Poehlein A, Kálalová D, Šanderová H, Daniel R, Krásný L, Stülke J. Quasi-essentiality of RNase Y in Bacillus subtilis is caused by its critical role in the control of mRNA homeostasis. Nucleic Acids Res 2021; 49:7088-7102. [PMID: 34157109 PMCID: PMC8266666 DOI: 10.1093/nar/gkab528] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 05/28/2021] [Accepted: 06/08/2021] [Indexed: 01/18/2023] Open
Abstract
RNA turnover is essential in all domains of life. The endonuclease RNase Y (rny) is one of the key components involved in RNA metabolism of the model organism Bacillus subtilis. Essentiality of RNase Y has been a matter of discussion, since deletion of the rny gene is possible, but leads to severe phenotypic effects. In this work, we demonstrate that the rny mutant strain rapidly evolves suppressor mutations to at least partially alleviate these defects. All suppressor mutants had acquired a duplication of an about 60 kb long genomic region encompassing genes for all three core subunits of the RNA polymerase—α, β, β′. When the duplication of the RNA polymerase genes was prevented by relocation of the rpoA gene in the B. subtilis genome, all suppressor mutants carried distinct single point mutations in evolutionary conserved regions of genes coding either for the β or β’ subunits of the RNA polymerase that were not tolerated by wild type bacteria. In vitro transcription assays with the mutated polymerase variants showed a severe decrease in transcription efficiency. Altogether, our results suggest a tight cooperation between RNase Y and the RNA polymerase to establish an optimal RNA homeostasis in B. subtilis cells.
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Affiliation(s)
- Martin Benda
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Simon Woelfel
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Patrick Faßhauer
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Katrin Gunka
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Stefan Klumpp
- Institute for the Dynamics of Complex Systems, Georg-August-University Göttingen, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Debora Kálalová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Šanderová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
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8
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Laalami S, Cavaiuolo M, Roque S, Chagneau C, Putzer H. Escherichia coli RNase E can efficiently replace RNase Y in Bacillus subtilis. Nucleic Acids Res 2021; 49:4643-4654. [PMID: 33788929 PMCID: PMC8096251 DOI: 10.1093/nar/gkab216] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 02/06/2023] Open
Abstract
RNase Y and RNase E are disparate endoribonucleases that govern global mRNA turnover/processing in the two evolutionary distant bacteria Bacillus subtilis and Escherichia coli, respectively. The two enzymes share a similar in vitro cleavage specificity and subcellular localization. To evaluate the potential equivalence in biological function between the two enzymes in vivo we analyzed whether and to what extent RNase E is able to replace RNase Y in B. subtilis. Full-length RNase E almost completely restores wild type growth of the rny mutant. This is matched by a surprising reversal of transcript profiles both of individual genes and on a genome-wide scale. The single most important parameter to efficient complementation is the requirement for RNase E to localize to the inner membrane while truncation of the C-terminal sequences corresponding to the degradosome scaffold has only a minor effect. We also compared the in vitro cleavage activity for the major decay initiating ribonucleases Y, E and J and show that no conclusions can be drawn with respect to their activity in vivo. Our data confirm the notion that RNase Y and RNase E have evolved through convergent evolution towards a low specificity endonuclease activity universally important in bacteria.
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Affiliation(s)
- Soumaya Laalami
- CNRS, UMR8261, Institut de Biologie Physico-Chimique, Université de Paris, 75005 Paris, France
| | - Marina Cavaiuolo
- CNRS, UMR8261, Institut de Biologie Physico-Chimique, Université de Paris, 75005 Paris, France
| | - Sylvain Roque
- CNRS, UMR8261, Institut de Biologie Physico-Chimique, Université de Paris, 75005 Paris, France
| | - Carine Chagneau
- CNRS, UMR8261, Institut de Biologie Physico-Chimique, Université de Paris, 75005 Paris, France
| | - Harald Putzer
- CNRS, UMR8261, Institut de Biologie Physico-Chimique, Université de Paris, 75005 Paris, France
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9
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Cavaiuolo M, Chagneau C, Laalami S, Putzer H. Impact of RNase E and RNase J on Global mRNA Metabolism in the Cyanobacterium Synechocystis PCC6803. Front Microbiol 2020; 11:1055. [PMID: 32582060 PMCID: PMC7283877 DOI: 10.3389/fmicb.2020.01055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/29/2020] [Indexed: 01/18/2023] Open
Abstract
mRNA levels result from an equilibrium between transcription and degradation. Ribonucleases (RNases) facilitate the turnover of mRNA, which is an important way of controlling gene expression, allowing the cells to adjust transcript levels to a changing environment. In contrast to the heterotrophic model bacteria Escherichia coli and Bacillus subtilis, RNA decay has not been studied in detail in cyanobacteria. Synechocystis sp. PCC6803 encodes orthologs of both E. coli and B. subtilis RNases, including RNase E and RNase J, respectively. We show that in vitro Sy RNases E and J have an endonucleolytic cleavage specificity that is very similar between them and also compared to orthologous enzymes from E. coli, B. subtilis, and Chlamydomonas. Moreover, Sy RNase J displays a robust 5′-exoribonuclease activity similar to B. subtilis RNase J1, but unlike the evolutionarily related RNase J in chloroplasts. Both nucleases are essential and gene deletions could not be fully segregated in Synechocystis. We generated partially disrupted strains of Sy RNase E and J that were stable enough to allow for their growth and characterization. A transcriptome analysis of these strains partially depleted for RNases E and J, respectively, allowed to observe effects on specific transcripts. RNase E altered the expression of a larger number of chromosomal genes and antisense RNAs compared to RNase J, which rather affects endogenous plasmid encoded transcripts. Our results provide the first description of the main transcriptomic changes induced by the partial depletion of two essential ribonucleases in cyanobacteria.
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Affiliation(s)
- Marina Cavaiuolo
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Carine Chagneau
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Soumaya Laalami
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Harald Putzer
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
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10
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Reply to Losick, "Concerns about Continuing Claims that a Protein Complex Interacts with the Phosphorelay". mBio 2020; 11:mBio.00154-20. [PMID: 32156813 PMCID: PMC7064756 DOI: 10.1128/mbio.00154-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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11
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Abstract
All living organisms must degrade mRNA to adapt gene expression to changing environments. In bacteria, initiation of mRNA decay generally occurs through an endonucleolytic cleavage. In the Gram-positive model organism Bacillus subtilis and probably many other bacteria, the key enzyme for this task is RNase Y, which is anchored at the inner cell membrane. While this pseudocompartmentalization appears coherent with translation occurring primarily at the cell periphery, our knowledge on the distribution and dynamics of RNase Y in living cells is very scarce. Here, we show that RNase Y moves rapidly along the membrane in the form of dynamic short-lived foci. These foci become more abundant and increase in size following transcription arrest, suggesting that they do not constitute the most active form of the nuclease. This contrasts with RNase E, the major decay-initiating RNase in E. coli, where it was shown that formation of foci is dependent on the presence of RNA substrates. We also show that a protein complex (Y-complex) known to influence the specificity of RNase Y activity in vivo is capable of shifting the assembly status of RNase Y toward fewer and smaller complexes. This highlights fundamental differences between RNase E- and RNase Y-based degradation machineries. Metabolic turnover of mRNA is fundamental to the control of gene expression in all organisms, notably in fast-adapting prokaryotes. In many bacteria, RNase Y initiates global mRNA decay via an endonucleolytic cleavage, as shown in the Gram-positive model organism Bacillus subtilis. This enzyme is tethered to the inner cell membrane, a pseudocompartmentalization coherent with its task of initiating mRNA cleavage/maturation of mRNAs that are translated at the cell periphery. Here, we used total internal reflection fluorescence microscopy (TIRFm) and single-particle tracking (SPT) to visualize RNase Y and analyze its distribution and dynamics in living cells. We find that RNase Y diffuses rapidly at the membrane in the form of dynamic short-lived foci. Unlike RNase E, the major decay-initiating RNase in Escherichia coli, the formation of foci is not dependent on the presence of RNA substrates. On the contrary, RNase Y foci become more abundant and increase in size following transcription arrest, suggesting that they do not constitute the most active form of the nuclease. The Y-complex of three proteins (YaaT, YlbF, and YmcA) has previously been shown to play an important role for RNase Y activity in vivo. We demonstrate that Y-complex mutations have an effect similar to but much stronger than that of depletion of RNA in increasing the number and size of RNase Y foci at the membrane. Our data suggest that the Y-complex shifts the assembly status of RNase Y toward fewer and smaller complexes, thereby increasing cleavage efficiency of complex substrates like polycistronic mRNAs.
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12
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Bechhofer DH, Deutscher MP. Bacterial ribonucleases and their roles in RNA metabolism. Crit Rev Biochem Mol Biol 2019; 54:242-300. [PMID: 31464530 PMCID: PMC6776250 DOI: 10.1080/10409238.2019.1651816] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/22/2019] [Accepted: 07/31/2019] [Indexed: 12/16/2022]
Abstract
Ribonucleases (RNases) are mediators in most reactions of RNA metabolism. In recent years, there has been a surge of new information about RNases and the roles they play in cell physiology. In this review, a detailed description of bacterial RNases is presented, focusing primarily on those from Escherichia coli and Bacillus subtilis, the model Gram-negative and Gram-positive organisms, from which most of our current knowledge has been derived. Information from other organisms is also included, where relevant. In an extensive catalog of the known bacterial RNases, their structure, mechanism of action, physiological roles, genetics, and possible regulation are described. The RNase complement of E. coli and B. subtilis is compared, emphasizing the similarities, but especially the differences, between the two. Included are figures showing the three major RNA metabolic pathways in E. coli and B. subtilis and highlighting specific steps in each of the pathways catalyzed by the different RNases. This compilation of the currently available knowledge about bacterial RNases will be a useful tool for workers in the RNA field and for others interested in learning about this area.
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Affiliation(s)
- David H. Bechhofer
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Murray P. Deutscher
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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13
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Abstract
RNases are key enzymes involved in RNA maturation and degradation. Although they play a crucial role in all domains of life, bacteria, archaea, and eukaryotes have evolved with their own sets of RNases and proteins modulating their activities. In bacteria, these enzymes allow modulation of gene expression to adapt to rapidly changing environments. Today, >20 RNases have been identified in both Escherichia coli and Bacillus subtilis, the paradigms of the Gram-negative and Gram-positive bacteria, respectively. However, only a handful of these enzymes are common to these two organisms and some of them are essential to only one. Moreover, although sets of RNases can be very similar in closely related bacteria such as the Firmicutes Staphylococcus aureus and B. subtilis, the relative importance of individual enzymes in posttranscriptional regulation in these organisms varies. In this review, we detail the role of the main RNases involved in RNA maturation and degradation in Gram-positive bacteria, with an emphasis on the roles of RNase J1, RNase III, and RNase Y. We also discuss how other proteins such as helicases can modulate the RNA-degradation activities of these enzymes.
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14
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Hardouin P, Velours C, Bou-Nader C, Assrir N, Laalami S, Putzer H, Durand D, Golinelli-Pimpaneau B. Dissociation of the Dimer of the Intrinsically Disordered Domain of RNase Y upon Antibody Binding. Biophys J 2018; 115:2102-2113. [PMID: 30447990 DOI: 10.1016/j.bpj.2018.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 09/17/2018] [Accepted: 10/17/2018] [Indexed: 12/12/2022] Open
Abstract
Although RNase Y acts as the key enzyme initiating messenger RNA decay in Bacillus subtilis and likely in many other Gram-positive bacteria, its three-dimensional structure remains unknown. An antibody belonging to the rare immunoglobulin G (IgG) 2b λx isotype was raised against a 12-residue conserved peptide from the N-terminal noncatalytic domain of B. subtilis RNase Y (BsRNaseY) that is predicted to be intrinsically disordered. Here, we show that this domain can be produced as a stand-alone protein called Nter-BsRNaseY that undergoes conformational changes between monomeric and dimeric forms. Circular dichroism and size exclusion chromatography coupled with multiangle light scattering or with small angle x-ray scattering indicate that the Nter-BsRNaseY dimer displays an elongated form and a high content of α-helices, in agreement with the existence of a central coiled-coil structure appended with flexible ends, and that the monomeric state of Nter-BsRNaseY is favored upon binding the fragment antigen binding (Fab) of the antibody. The dissociation constants of the IgG/BsRNaseY, IgG/Nter-BsRNaseY, and IgG/peptide complexes indicate that the affinity of the IgG for Nter-BsRNaseY is in the nM range and suggest that the peptide is less accessible in BsRNaseY than in Nter-BsRNaseY. The crystal structure of the Fab in complex with the peptide antigen shows that the peptide adopts an elongated U-shaped conformation in which the unique hydrophobic residue of the peptide, Leu6, is completely buried. The peptide/Fab complex may mimic the interaction of a microdomain of the N-terminal domain of BsRNaseY with one of its cellular partners within the degradosome complex. Altogether, our results suggest that BsRNaseY may become accessible for protein interaction upon dissociation of its N-terminal domain into the monomeric form.
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Affiliation(s)
- Pierre Hardouin
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France
| | - Christophe Velours
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Charles Bou-Nader
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France
| | - Nadine Assrir
- Structural Chemistry and Biology Team, Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Soumaya Laalami
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Harald Putzer
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Béatrice Golinelli-Pimpaneau
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Université Pierre et Marie Curie, Paris CEDEX 05, France.
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15
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Mora L, Ngo S, Laalami S, Putzer H. In Vitro Study of the Major Bacillus subtilis Ribonucleases Y and J. Methods Enzymol 2018; 612:343-359. [PMID: 30502948 DOI: 10.1016/bs.mie.2018.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The metabolic instability of mRNA is fundamental to the adaptation of gene expression. In bacteria, mRNA decay follows first-order kinetics and is primarily controlled at the steps initiating degradation. In the model Gram-positive organism Bacillus subtilis, the major mRNA decay pathway initiates with an endonucleolytic cleavage by the membrane-associated RNase Y. High-throughput sequencing has identified a large number of potential mRNA substrates but our understanding of what parameters affect cleavage in vivo is still quite limited. In vitro reconstitution of the cleavage event is thus instrumental in defining the mechanistic details, substrate recognition, the role of auxiliary factors, and of membrane localization in cleavage. In this chapter, we describe not only the purification and assay of RNase Y but also RNase J1/J2 which shares a similar low-specificity endoribonucleolytic activity with RNase Y. We highlight potential problems in the set-up of these assays and include methods that allow purification of full-length RNase Y and its incorporation in multilamellar vesicles created from native B. subtilis lipids that might best mimic in vivo conditions.
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Affiliation(s)
- Liliana Mora
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Saravuth Ngo
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Soumaya Laalami
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Harald Putzer
- CNRS UMR8261-Université Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France.
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16
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Maturation of polycistronic mRNAs by the endoribonuclease RNase Y and its associated Y-complex in Bacillus subtilis. Proc Natl Acad Sci U S A 2018; 115:E5585-E5594. [PMID: 29794222 DOI: 10.1073/pnas.1803283115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Endonucleolytic cleavage within polycistronic mRNAs can lead to differential stability, and thus discordant abundance, among cotranscribed genes. RNase Y, the major endonuclease for mRNA decay in Bacillus subtilis, was originally identified for its cleavage activity toward the cggR-gapA operon, an event that differentiates the synthesis of a glycolytic enzyme from its transcriptional regulator. A three-protein Y-complex (YlbF, YmcA, and YaaT) was recently identified as also being required for this cleavage in vivo, raising the possibility that it is an accessory factor acting to regulate RNase Y. However, whether the Y-complex is broadly required for RNase Y activity is unknown. Here, we used end-enrichment RNA sequencing (Rend-seq) to globally identify operon mRNAs that undergo maturation posttranscriptionally by RNase Y and the Y-complex. We found that the Y-complex is required for the majority of RNase Y-mediated mRNA maturation events and also affects riboswitch abundance in B. subtilis In contrast, noncoding RNA maturation by RNase Y often does not require the Y-complex. Furthermore, deletion of RNase Y has more pleiotropic effects on the transcriptome and cell growth than deletions of the Y-complex. We propose that the Y-complex is a specificity factor for RNase Y, with evidence that its role is conserved in Staphylococcus aureus.
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17
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Braun F, Durand S, Condon C. Initiating ribosomes and a 5'/3'-UTR interaction control ribonuclease action to tightly couple B. subtilis hbs mRNA stability with translation. Nucleic Acids Res 2017; 45:11386-11400. [PMID: 28977557 PMCID: PMC5737220 DOI: 10.1093/nar/gkx793] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/29/2017] [Indexed: 12/19/2022] Open
Abstract
We previously showed that ribosomes initiating translation of the B. subtilis hbs mRNA at a strong Shine–Dalgarno sequence block the 5′ exoribonuclease RNase J1 from degrading into the coding sequence. Here, we identify new and previously unsuspected features of this mRNA. First, we identify RNase Y as the endoribonuclease that cleaves the highly structured 5′-UTR to give access to RNase J1. Cleavage by RNase Y at this site is modulated by a 14-bp long-range interaction between the 5′- and 3-UTRs that partially overlaps the cleavage site. In addition to this maturation/degradation pathway, we discovered a new and ultimately more important RNase Y cleavage site in the very early coding sequence, masked by the initiating ribosome. Thus, two independent pathways compete with ribosomes to tightly link hbs mRNA stability to translation initiation; in one case the initiating ribosome competes directly with RNase J1 and in the other with RNase Y. This is in contrast to prevailing models in Escherichia coli where ribosome traffic over the ORF is the main source of protection from RNases. Indeed, a second RNase Y cleavage site later in the hbs ORF plays no role in its turnover, confirming that for this mRNA at least, initiation is key.
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Affiliation(s)
- Frédérique Braun
- UMR 8261 (CNRS-Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Sylvain Durand
- UMR 8261 (CNRS-Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Ciarán Condon
- UMR 8261 (CNRS-Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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18
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Bidnenko V, Nicolas P, Grylak-Mielnicka A, Delumeau O, Auger S, Aucouturier A, Guerin C, Repoila F, Bardowski J, Aymerich S, Bidnenko E. Termination factor Rho: From the control of pervasive transcription to cell fate determination in Bacillus subtilis. PLoS Genet 2017; 13:e1006909. [PMID: 28723971 PMCID: PMC5540618 DOI: 10.1371/journal.pgen.1006909] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/02/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023] Open
Abstract
In eukaryotes, RNA species originating from pervasive transcription are regulators of various cellular processes, from the expression of individual genes to the control of cellular development and oncogenesis. In prokaryotes, the function of pervasive transcription and its output on cell physiology is still unknown. Most bacteria possess termination factor Rho, which represses pervasive, mostly antisense, transcription. Here, we investigate the biological significance of Rho-controlled transcription in the Gram-positive model bacterium Bacillus subtilis. Rho inactivation strongly affected gene expression in B. subtilis, as assessed by transcriptome and proteome analysis of a rho-null mutant during exponential growth in rich medium. Subsequent physiological analyses demonstrated that a considerable part of Rho-controlled transcription is connected to balanced regulation of three mutually exclusive differentiation programs: cell motility, biofilm formation, and sporulation. In the absence of Rho, several up-regulated sense and antisense transcripts affect key structural and regulatory elements of these differentiation programs, thereby suppressing motility and biofilm formation and stimulating sporulation. We dissected how Rho is involved in the activity of the cell fate decision-making network, centered on the master regulator Spo0A. We also revealed a novel regulatory mechanism of Spo0A activation through Rho-dependent intragenic transcription termination of the protein kinase kinB gene. Altogether, our findings indicate that distinct Rho-controlled transcripts are functional and constitute a previously unknown built-in module for the control of cell differentiation in B. subtilis. In a broader context, our results highlight the recruitment of the termination factor Rho, for which the conserved biological role is probably to repress pervasive transcription, in highly integrated, bacterium-specific, regulatory networks.
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Affiliation(s)
- Vladimir Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Pierre Nicolas
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Aleksandra Grylak-Mielnicka
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
- Institute of Biochemistry and Biophysics PAS, Warsaw, Poland
| | - Olivier Delumeau
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sandrine Auger
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Anne Aucouturier
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Cyprien Guerin
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Francis Repoila
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jacek Bardowski
- Institute of Biochemistry and Biophysics PAS, Warsaw, Poland
| | - Stéphane Aymerich
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Elena Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
- * E-mail:
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19
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Leroy M, Piton J, Gilet L, Pellegrini O, Proux C, Coppée JY, Figaro S, Condon C. Rae1/YacP, a new endoribonuclease involved in ribosome-dependent mRNA decay in Bacillus subtilis. EMBO J 2017; 36:1167-1181. [PMID: 28363943 DOI: 10.15252/embj.201796540] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 11/09/2022] Open
Abstract
The PIN domain plays a central role in cellular RNA biology and is involved in processes as diverse as rRNA maturation, mRNA decay and telomerase function. Here, we solve the crystal structure of the Rae1 (YacP) protein of Bacillus subtilis, a founding member of the NYN (Nedd4-BP1/YacP nuclease) subfamily of PIN domain proteins, and identify potential substrates in vivo Unexpectedly, degradation of a characterised target mRNA was completely dependent on both its translation and reading frame. We provide evidence that Rae1 associates with the B. subtilis ribosome and cleaves between specific codons of this mRNA in vivo Critically, we also demonstrate translation-dependent Rae1 cleavage of this substrate in a purified translation assay in vitro Multiple lines of evidence converge to suggest that Rae1 is an A-site endoribonuclease. We present a docking model of Rae1 bound to the B. subtilis ribosomal A-site that is consistent with this hypothesis and show that Rae1 cleaves optimally immediately upstream of a lysine codon (AAA or AAG) in vivo.
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Affiliation(s)
- Magali Leroy
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Jérémie Piton
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Laetitia Gilet
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Olivier Pellegrini
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Caroline Proux
- Transcriptome and EpiGenome, Biomics Center for Innovation and Technological Research Institut Pasteur, Paris, France
| | - Jean-Yves Coppée
- Transcriptome and EpiGenome, Biomics Center for Innovation and Technological Research Institut Pasteur, Paris, France
| | - Sabine Figaro
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Ciarán Condon
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
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20
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Hausmann S, Guimarães VA, Garcin D, Baumann N, Linder P, Redder P. Both exo- and endo-nucleolytic activities of RNase J1 from Staphylococcus aureus are manganese dependent and active on triphosphorylated 5'-ends. RNA Biol 2017; 14:1431-1443. [PMID: 28277929 DOI: 10.1080/15476286.2017.1300223] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
RNA decay and RNA maturation are important steps in the regulation of bacterial gene expression. RNase J, which is present in about half of bacterial species, has been shown to possess both endo- and 5' to 3' exo-ribonuclease activities. The exonucleolytic activity is clearly involved in the degradation of mRNA and in the maturation of at least the 5' end of 16S rRNA in the 2 Firmicutes Staphylococcus aureus and Bacillus subtilis. The endoribonuclease activity of RNase J from several species has been shown to be weak in vitro and 3-D structural data of different RNase J orthologs have not provided a clear explanation for the molecular basis of this activity. Here, we show that S. aureus RNase J1 is a manganese dependent homodimeric enzyme with strong 5' to 3' exo-ribonuclease as well as endo-ribonuclease activity. In addition, we demonstrated that SauJ1 can efficiently degrade 5' triphosphorylated RNA. Our results highlight RNase J1 as an important player in RNA turnover in S. aureus.
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Affiliation(s)
- Stéphane Hausmann
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland
| | - Vanessa Andrade Guimarães
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland
| | - Dominique Garcin
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland
| | - Natalia Baumann
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland
| | - Patrick Linder
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland
| | - Peter Redder
- a Department of Microbiology and Molecular Medicine , Medical Faculty, University of Geneva , Geneva , Switzerland.,b Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative, Université de Toulouse III Toulouse , France
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21
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Role of RNase Y in Clostridium perfringens mRNA Decay and Processing. J Bacteriol 2016; 199:JB.00703-16. [PMID: 27821608 DOI: 10.1128/jb.00703-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 10/27/2016] [Indexed: 11/20/2022] Open
Abstract
RNase Y is a major endoribonuclease that plays a crucial role in mRNA degradation and processing. We study the role of RNase Y in the Gram-positive anaerobic pathogen Clostridium perfringens, which until now has not been well understood. Our study implies an important role for RNase Y-mediated RNA degradation and processing in virulence gene expression and the physiological development of the organism. We began by constructing an RNase Y conditional knockdown strain in order to observe the importance of RNase Y on growth and virulence. Our resulting transcriptome analysis shows that RNase Y affects the expression of many genes, including toxin-producing genes. We provide data to show that RNase Y depletion repressed several toxin genes in C. perfringens and involved the virR-virS two-component system. We also observe evidence that RNase Y is indispensable for processing and stabilizing the transcripts of colA (encoding a major toxin collagenase) and pilA2 (encoding a major pilin component of the type IV pili). Posttranscriptional regulation of colA is known to be mediated by cleavage in the 5' untranslated region (5'UTR), and we observe that RNase Y depletion diminishes colA 5'UTR processing. We show that RNase Y is also involved in the posttranscriptional stabilization of pilA2 mRNA, which is thought to be important for host cell adherence and biofilm formation. IMPORTANCE RNases have important roles in RNA degradation and turnover in all organisms. C. perfringens is a Gram-positive anaerobic spore-forming bacterial pathogen that produces numerous extracellular enzymes and toxins, and it is linked to digestive disorders and disease. A highly conserved endoribonuclease, RNase Y, affects the expression of hundreds of genes, including toxin genes, and studying these effects is useful for understanding C. perfringens specifically and RNases generally. Moreover, RNase Y is involved in processing specific transcripts, and we observed that this processing in C. perfringens results in the stabilization of mRNAs encoding a toxin and bacterial extracellular apparatus pili. Our study shows that RNase activity is associated with gene expression, helping to determine the growth, proliferation, and virulence of C. perfringens.
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22
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Ogura M, Asai K. Glucose Induces ECF Sigma Factor Genes, sigX and sigM, Independent of Cognate Anti-sigma Factors through Acetylation of CshA in Bacillus subtilis. Front Microbiol 2016; 7:1918. [PMID: 27965645 PMCID: PMC5126115 DOI: 10.3389/fmicb.2016.01918] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/15/2016] [Indexed: 12/23/2022] Open
Abstract
Extracytoplasmic function (ECF) σ factors have roles related to cell envelope and/or cell membrane functions, in addition to other cellular functions. Without cell-surface stresses, ECF σ factors are sequestered by the cognate anti-σ factor, leading to inactivation and the resultant repression of regulons due to the inhibition of transcription of their own genes. Bacillus subtilis has seven ECF σ factors including σX and σM that transcribe their own structural genes. Here, we report that glucose addition to the medium induced sigX and sigM transcription independent of their anti-σ factors. This induction was dependent on an intracellular acetyl-CoA pool. Transposon mutagenesis searching for the mutants showing no induction of sigX and sigM revealed that the cshA gene encoding DEAD-box RNA helicase is required for gene induction. Global analysis of the acetylome in B. subtilis showed CshA has two acetylated lysine residues. We found that in a cshA mutant with acetylation-abolishing K to R exchange mutations, glucose induction of sigX and sigM was abolished and that glucose addition stimulated acetylation of CshA in the wild type strain. Thus, we present a model wherein glucose addition results in a larger acetyl-CoA pool, probably leading to increased levels of acetylated CshA. CshA is known to associate with RNA polymerase (RNAP), and thus RNAP with acetylated CshA could stimulate the autoregulation of sigX and sigM. This is a unique model showing a functional link between nutritional signals and the basal transcription machinery.
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Affiliation(s)
- Mitsuo Ogura
- Institute of Oceanic Research and Development, Tokai University Shizuoka, Japan
| | - Kei Asai
- Department of Bioscience, Saitama University Saitama, Japan
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23
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Le Rhun A, Beer YY, Reimegård J, Chylinski K, Charpentier E. RNA sequencing uncovers antisense RNAs and novel small RNAs in Streptococcus pyogenes. RNA Biol 2016; 13:177-95. [PMID: 26580233 PMCID: PMC4829319 DOI: 10.1080/15476286.2015.1110674] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Streptococcus pyogenes is a human pathogen responsible for a wide spectrum of diseases ranging from mild to life-threatening infections. During the infectious process, the temporal and spatial expression of pathogenicity factors is tightly controlled by a complex network of protein and RNA regulators acting in response to various environmental signals. Here, we focus on the class of small RNA regulators (sRNAs) and present the first complete analysis of sRNA sequencing data in S. pyogenes. In the SF370 clinical isolate (M1 serotype), we identified 197 and 428 putative regulatory RNAs by visual inspection and bioinformatics screening of the sequencing data, respectively. Only 35 from the 197 candidates identified by visual screening were assigned a predicted function (T-boxes, ribosomal protein leaders, characterized riboswitches or sRNAs), indicating how little is known about sRNA regulation in S. pyogenes. By comparing our list of predicted sRNAs with previous S. pyogenes sRNA screens using bioinformatics or microarrays, 92 novel sRNAs were revealed, including antisense RNAs that are for the first time shown to be expressed in this pathogen. We experimentally validated the expression of 30 novel sRNAs and antisense RNAs. We show that the expression profile of 9 sRNAs including 2 predicted regulatory elements is affected by the endoribonucleases RNase III and/or RNase Y, highlighting the critical role of these enzymes in sRNA regulation.
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Affiliation(s)
- Anaïs Le Rhun
- a The Laboratory for Molecular Infection Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology; Umeå University, S-90187 , Umeå , Sweden.,b Helmholtz Centre for Infection Research (HZI), Department of Regulation in Infection Biology, D-38124 , Braunschweig , Germany
| | - Yan Yan Beer
- b Helmholtz Centre for Infection Research (HZI), Department of Regulation in Infection Biology, D-38124 , Braunschweig , Germany
| | - Johan Reimegård
- c Science for Life Laboratory , Department of Cell and Molecular Biology, Uppsala University, S-75003 , Uppsala , Sweden
| | - Krzysztof Chylinski
- a The Laboratory for Molecular Infection Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology; Umeå University, S-90187 , Umeå , Sweden.,d Max F. Perutz Laboratories (MFPL), University of Vienna, A-1030 , Vienna , Austria
| | - Emmanuelle Charpentier
- a The Laboratory for Molecular Infection Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology; Umeå University, S-90187 , Umeå , Sweden.,b Helmholtz Centre for Infection Research (HZI), Department of Regulation in Infection Biology, D-38124 , Braunschweig , Germany.,e Hannover Medical School (MHH), D-30625 , Hannover , Germany.,f Max Planck Institute for Infection Biology , Department of Regulation in Infection Biology, D-10117 , Berlin , Germany
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24
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Dubnau EJ, Carabetta VJ, Tanner AW, Miras M, Diethmaier C, Dubnau D. A protein complex supports the production of Spo0A-P and plays additional roles for biofilms and the K-state in Bacillus subtilis. Mol Microbiol 2016; 101:606-24. [PMID: 27501195 DOI: 10.1111/mmi.13411] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2016] [Indexed: 01/19/2023]
Abstract
Bacillus subtilis can enter three developmental pathways to form spores, biofilms or K-state cells. The K-state confers competence for transformation and antibiotic tolerance. Transition into each of these states requires a stable protein complex formed by YlbF, YmcA and YaaT. We have reported that this complex acts in sporulation by accelerating the phosphorylation of the response regulator Spo0A. Phosphorelay acceleration was also predicted to explain their involvement in biofilm formation and the K-state. This view has been challenged in the case of biofilms, by the suggestion that the three proteins act in association with the mRNA degradation protein RNaseY (Rny) to destabilize the sinR transcript. Here, we reaffirm the roles of the three proteins in supporting the phosphorylation of Spo0A for all three developmental pathways and show that in their absence sinR mRNA is not stabilized. We demonstrate that the three proteins also play unknown Spo0A-P-independent roles in the expression of biofilm matrix and in the production of ComK, the master transcription factor for competence. Finally, we show that domesticated strains of B. subtilis carry a mutation in sigH, which influences the expression kinetics of the early spore gene spoIIG, thereby increasing the penetrance of the ylbF, ymcA and yaaT sporulation phenotypes.
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Affiliation(s)
- Eugenie J Dubnau
- Public Health Research Institute Center.,Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | - Valerie J Carabetta
- Public Health Research Institute Center.,Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | - Andrew W Tanner
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | | | | | - David Dubnau
- Public Health Research Institute Center.,Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
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25
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Abstract
Gram-negative and gram-positive bacteria use a variety of enzymatic pathways to degrade mRNAs. Although several recent reviews have outlined these pathways, much less attention has been paid to the regulation of mRNA decay. The functional half-life of a particular mRNA, which affects how much protein is synthesized from it, is determined by a combination of multiple factors. These include, but are not necessarily limited to, (a) stability elements at either the 5' or the 3' terminus, (b) posttranscriptional modifications, (c) ribosome density on individual mRNAs, (d) small regulatory RNA (sRNA) interactions with mRNAs, (e) regulatory proteins that alter ribonuclease binding affinities, (f) the presence or absence of endonucleolytic cleavage sites, (g) control of intracellular ribonuclease levels, and (h) physical location within the cell. Changes in physiological conditions associated with environmental alterations can significantly alter the impact of these factors in the decay of a particular mRNA.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, Georgia 30602;
| | - Sidney R Kushner
- Department of Genetics, University of Georgia, Athens, Georgia 30602;
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Müller P, Jahn N, Ring C, Maiwald C, Neubert R, Meißner C, Brantl S. A multistress responsive type I toxin-antitoxin system: bsrE/SR5 from the B. subtilis chromosome. RNA Biol 2016; 13:511-23. [PMID: 26940229 DOI: 10.1080/15476286.2016.1156288] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
bsrE/SR5 is a type I TA system from prophage-like element P6 of the B. subtilis chromosome. The 256 nt bsrE RNA encodes a 30 aa toxin. The antitoxin SR5 is a 163 nt antisense RNA. Both genes overlap at their 3' ends. Overexpression of bsrE causes cell lysis on agar plates, which can be neutralized by sr5 overexpression, whereas deletion of the chromosomal sr5 copy has no effect. SR5 is short-lived with a half-life of ≈7 min, whereas bsrE RNA is stable with a half-life of >80 min. The sr5 promoter is 10-fold stronger than the bsrE promoter. SR5 interacts with the 3' UTR of bsrE RNA, thereby promoting its degradation by recruiting RNase III. RNase J1 is the main RNase responsible for SR5 and bsrE RNA degradation, and PnpA processes an SR5 precursor to the mature RNA. Hfq stabilizes SR5, but is not required for its inhibitory function. While bsrE RNA is affected by temperature shock and alkaline stress, the amount of SR5 is significantly influenced by various stresses, among them pH, anoxia and iron limitation. Only the latter one is dependent on sigB. Both RNAs are extremely unstable upon ethanol stress due to rapid degradation by RNase Y.
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Affiliation(s)
- Peter Müller
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Natalie Jahn
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Christiane Ring
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Caroline Maiwald
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Robert Neubert
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Christin Meißner
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
| | - Sabine Brantl
- a Friedrich-Schiller-Universität Jena , Lehrstuhl für Genetik , AG Bakteriengenetik, Philosophenweg, Jena , Germany
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27
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Jahn N, Brantl S. Heat-shock-induced refolding entails rapid degradation of bsrG toxin mRNA by RNases Y and J1. Microbiology (Reading) 2016; 162:590-599. [DOI: 10.1099/mic.0.000247] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Natalie Jahn
- Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, 07743 Jena, Germany
| | - Sabine Brantl
- Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, 07743 Jena, Germany
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28
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In silico approaches for the identification of virulence candidates amongst hypothetical proteins of Mycoplasma pneumoniae 309. Comput Biol Chem 2015; 59 Pt A:67-80. [DOI: 10.1016/j.compbiolchem.2015.09.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 09/08/2015] [Accepted: 09/14/2015] [Indexed: 01/25/2023]
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29
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Redder P, Hausmann S, Khemici V, Yasrebi H, Linder P. Bacterial versatility requires DEAD-box RNA helicases. FEMS Microbiol Rev 2015; 39:392-412. [PMID: 25907111 DOI: 10.1093/femsre/fuv011] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 11/13/2022] Open
Abstract
RNA helicases of the DEAD-box and DEAH-box families are important players in many processes involving RNA molecules. These proteins can modify RNA secondary structures or intermolecular RNA interactions and modulate RNA-protein complexes. In bacteria, they are known to be involved in ribosome biogenesis, RNA turnover and translation initiation. They thereby play an important role in the adaptation of bacteria to changing environments and to respond to stress conditions.
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Affiliation(s)
- Peter Redder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Stéphane Hausmann
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Vanessa Khemici
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Haleh Yasrebi
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
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30
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Dulermo R, Onodera T, Coste G, Passot F, Dutertre M, Porteron M, Confalonieri F, Sommer S, Pasternak C. Identification of new genes contributing to the extreme radioresistance of Deinococcus radiodurans using a Tn5-based transposon mutant library. PLoS One 2015; 10:e0124358. [PMID: 25884619 PMCID: PMC4401554 DOI: 10.1371/journal.pone.0124358] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/02/2015] [Indexed: 01/19/2023] Open
Abstract
Here, we have developed an extremely efficient in vivo Tn5-based mutagenesis procedure to construct a Deinococcus radiodurans insertion mutant library subsequently screened for sensitivity to genotoxic agents such as γ and UV radiations or mitomycin C. The genes inactivated in radiosensitive mutants belong to various functional categories, including DNA repair functions, stress responses, signal transduction, membrane transport, several metabolic pathways, and genes of unknown function. Interestingly, preliminary characterization of previously undescribed radiosensitive mutants suggests the contribution of cyclic di-AMP signaling in the recovery of D. radiodurans cells from genotoxic stresses, probably by modulating several pathways involved in the overall cell response. Our analyses also point out a new transcriptional regulator belonging to the GntR family, encoded by DR0265, and a predicted RNase belonging to the newly described Y family, both contributing to the extreme radioresistance of D. radiodurans. Altogether, this work has revealed new cell responses involved either directly or indirectly in repair of various cell damage and confirmed that D. radiodurans extreme radiation resistance is determined by a multiplicity of pathways acting as a complex network.
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Affiliation(s)
- Rémi Dulermo
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Takefumi Onodera
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Geneviève Coste
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Fanny Passot
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Murielle Dutertre
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Martine Porteron
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Fabrice Confalonieri
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Suzanne Sommer
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
| | - Cécile Pasternak
- Univ. Paris-Sud, Institute for Integrative Biology of the Cell (I2BC), Université Paris Saclay, CEA, CNRS, Orsay, France
- * E-mail:
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31
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Abstract
mRNA degradation is an important mechanism for controlling gene expression in bacterial cells. This process involves the orderly action of a battery of cellular endonucleases and exonucleases, some universal and others present only in certain species. These ribonucleases function with the assistance of ancillary enzymes that covalently modify the 5' or 3' end of RNA or unwind base-paired regions. Triggered by initiating events at either the 5' terminus or an internal site, mRNA decay occurs at diverse rates that are transcript specific and governed by RNA sequence and structure, translating ribosomes, and bound sRNAs or proteins. In response to environmental cues, bacteria are able to orchestrate widespread changes in mRNA lifetimes by modulating the concentration or specific activity of cellular ribonucleases or by unmasking the mRNA-degrading activity of cellular toxins.
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Affiliation(s)
- Monica P Hui
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Microbiology, New York University School of Medicine, New York, NY 10016;
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32
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A highly unstable transcript makes CwlO D,L-endopeptidase expression responsive to growth conditions in Bacillus subtilis. J Bacteriol 2013; 196:237-47. [PMID: 24163346 DOI: 10.1128/jb.00986-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Bacillus subtilis cell wall is a dynamic structure, composed of peptidoglycan and teichoic acid, that is continually remodeled during growth. Remodeling is effected by the combined activities of penicillin binding proteins and autolysins that participate in the synthesis and turnover of peptidoglycan, respectively. It has been established that one or the other of the CwlO and LytE D,L-endopeptidase-type autolysins is essential for cell viability, a requirement that is fulfilled by coordinate control of their expression by WalRK and SigI RsgI. Here we report on the regulation of cwlO expression. The cwlO transcript is very unstable, with its degradation initiated by RNase Y cleavage within the 187-nucleotide leader sequence. An antisense cwlO transcript of heterogeneous length is expressed from a SigB promoter that has the potential to control cellular levels of cwlO RNA and protein under stress conditions. We discuss how a multiplicity of regulatory mechanisms makes CwlO expression and activity responsive to the prevailing growth conditions.
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Initiation of mRNA decay in bacteria. Cell Mol Life Sci 2013; 71:1799-828. [PMID: 24064983 PMCID: PMC3997798 DOI: 10.1007/s00018-013-1472-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/01/2013] [Accepted: 09/03/2013] [Indexed: 12/24/2022]
Abstract
The instability of messenger RNA is fundamental to the control of gene expression. In bacteria, mRNA degradation generally follows an "all-or-none" pattern. This implies that if control is to be efficient, it must occur at the initiating (and presumably rate-limiting) step of the degradation process. Studies of E. coli and B. subtilis, species separated by 3 billion years of evolution, have revealed the principal and very disparate enzymes involved in this process in the two organisms. The early view that mRNA decay in these two model organisms is radically different has given way to new models that can be resumed by "different enzymes-similar strategies". The recent characterization of key ribonucleases sheds light on an impressive case of convergent evolution that illustrates that the surprisingly similar functions of these totally unrelated enzymes are of general importance to RNA metabolism in bacteria. We now know that the major mRNA decay pathways initiate with an endonucleolytic cleavage in E. coli and B. subtilis and probably in many of the currently known bacteria for which these organisms are considered representative. We will discuss here the different pathways of eubacterial mRNA decay, describe the major players and summarize the events that can precede and/or favor nucleolytic inactivation of a mRNA, notably the role of the 5' end and translation initiation. Finally, we will discuss the role of subcellular compartmentalization of transcription, translation, and the RNA degradation machinery.
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