1
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Jagodnik J, Darfeuille F, Guillier M. Disentangling the pseudoknots of toxin translation. Proc Natl Acad Sci U S A 2024; 121:e2411591121. [PMID: 39024107 PMCID: PMC11295053 DOI: 10.1073/pnas.2411591121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024] Open
Affiliation(s)
- Jonathan Jagodnik
- Microbial Gene Expression department, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, Paris75005, France
| | - Fabien Darfeuille
- University of Bordeaux, Department of Technology for Health, INSERM U1212, CNRS UMR 5320, ARN: Régulation Naturelle et Artificielle (ARNA) Laboratory, BordeauxF-33000, France
| | - Maude Guillier
- Microbial Gene Expression department, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, Paris75005, France
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2
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Shore SFH, Leinberger FH, Fozo EM, Berghoff BA. Type I toxin-antitoxin systems in bacteria: from regulation to biological functions. EcoSal Plus 2024:eesp00252022. [PMID: 38767346 DOI: 10.1128/ecosalplus.esp-0025-2022] [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: 09/29/2023] [Accepted: 04/11/2024] [Indexed: 05/22/2024]
Abstract
Toxin-antitoxin systems are ubiquitous in the prokaryotic world and widely distributed among chromosomes and mobile genetic elements. Several different toxin-antitoxin system types exist, but what they all have in common is that toxin activity is prevented by the cognate antitoxin. In type I toxin-antitoxin systems, toxin production is controlled by an RNA antitoxin and by structural features inherent to the toxin messenger RNA. Most type I toxins are small membrane proteins that display a variety of cellular effects. While originally discovered as modules that stabilize plasmids, chromosomal type I toxin-antitoxin systems may also stabilize prophages, or serve important functions upon certain stress conditions and contribute to population-wide survival strategies. Here, we will describe the intricate RNA-based regulation of type I toxin-antitoxin systems and discuss their potential biological functions.
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Affiliation(s)
- Selene F H Shore
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Florian H Leinberger
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Bork A Berghoff
- Institute for Microbiology and Molecular Biology, Justus-Liebig University, Giessen, Germany
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3
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Bonabal S, Darfeuille F. Preventing toxicity in toxin-antitoxin systems: An overview of regulatory mechanisms. Biochimie 2024; 217:95-105. [PMID: 37473832 DOI: 10.1016/j.biochi.2023.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Toxin-antitoxin systems (TAs) are generally two-component genetic modules present in almost every prokaryotic genome. The production of the free and active toxin is able to disrupt key cellular processes leading to the growth inhibition or death of its host organism in absence of its cognate antitoxin. The functions attributed to TAs rely on this lethal phenotype ranging from mobile genetic elements stabilization to phage defense. Their abundance in prokaryotic genomes as well as their lethal potential make them attractive targets for new antibacterial strategies. The hijacking of TAs requires a deep understanding of their regulation to be able to design such approach. In this review, we summarize the accumulated knowledge on how bacteria cope with these toxic genes in their genome. The characterized TAs can be grouped based on the way they prevent toxicity. Some systems rely on a tight control of the expression to prevent the production of the toxin while others control the activity of the toxin at the post-translational level.
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Affiliation(s)
- Simon Bonabal
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France
| | - Fabien Darfeuille
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France.
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4
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Schilling T, Ferrero-Bordera B, Neef J, Maaβ S, Becher D, van Dijl JM. Let There Be Light: Genome Reduction Enables Bacillus subtilis to Produce Disulfide-Bonded Gaussia Luciferase. ACS Synth Biol 2023; 12:3656-3668. [PMID: 38011677 PMCID: PMC10729301 DOI: 10.1021/acssynbio.3c00444] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 11/09/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023]
Abstract
Bacillus subtilis is a major workhorse for enzyme production in industrially relevant quantities. Compared to mammalian-based expression systems, B. subtilis presents intrinsic advantages, such as high growth rates, high space-time yield, unique protein secretion capabilities, and low maintenance costs. However, B. subtilis shows clear limitations in the production of biopharmaceuticals, especially proteins from eukaryotic origin that contain multiple disulfide bonds. In the present study, we deployed genome minimization, signal peptide screening, and coexpression of recombinant thiol oxidases as strategies to improve the ability of B. subtilis to secrete proteins with multiple disulfide bonds. Different genome-reduced strains served as the chassis for expressing the model protein Gaussia Luciferase (GLuc), which contains five disulfide bonds. These chassis lack extracellular proteases, prophages, and key sporulation genes. Importantly, compared to the reference strain with a full-size genome, the best-performing genome-minimized strain achieved over 3000-fold increased secretion of active GLuc while growing to lower cell densities. Our results show that high-level GLuc secretion relates, at least in part, to the absence of major extracellular proteases. In addition, we show that the thiol-disulfide oxidoreductase requirements for disulfide bonding have changed upon genome reduction. Altogether, our results highlight genome-engineered Bacillus strains as promising expression platforms for proteins with multiple disulfide bonds.
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Affiliation(s)
- Tobias Schilling
- Department
of Medical Microbiology, University of Groningen,
University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700RB Groningen, The Netherlands
| | - Borja Ferrero-Bordera
- Institute
of Microbiology Department of Microbial Proteomics, University of Greifswald, D-17489 Greifswald, Germany
| | - Jolanda Neef
- Department
of Medical Microbiology, University of Groningen,
University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700RB Groningen, The Netherlands
| | - Sandra Maaβ
- Institute
of Microbiology Department of Microbial Proteomics, University of Greifswald, D-17489 Greifswald, Germany
| | - Dörte Becher
- Institute
of Microbiology Department of Microbial Proteomics, University of Greifswald, D-17489 Greifswald, Germany
| | - Jan Maarten van Dijl
- Department
of Medical Microbiology, University of Groningen,
University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700RB Groningen, The Netherlands
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5
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Liu D, Lv H, Wang Y, Chen J, Li D, Huang R. Selective RNA Processing and Stabilization are Multi-Layer and Stoichiometric Regulators of Gene Expression in Escherichia coli. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301459. [PMID: 37845007 PMCID: PMC10667835 DOI: 10.1002/advs.202301459] [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: 03/06/2023] [Revised: 08/29/2023] [Indexed: 10/18/2023]
Abstract
Selective RNA processing and stabilization (SRPS) facilitates the differential expression of multiple genes in polycistronic operons. However, how the coordinated actions of SRPS-related enzymes affect stoichiometric regulation remains unclear. In the present study, the first genome-wide targetome analysis is reported of these enzymes in Escherichia coli, at a single-nucleotide resolution. A strictly linear relationship is observed between the RNA pyrophosphohydrolase processing ratio and scores assigned to the first three nucleotides of the primary transcript. Stem-loops associated with PNPase targetomes exhibit a folding free energy that is negatively correlated with the termination ratio of PNPase at the 3' end. More than one-tenth of the RNase E processing sites in the 5'-untranslated regions(UTR) form different stem-loops that affect ribosome-binding and translation efficiency. The effectiveness of the SRPS elements is validated using a dual-fluorescence reporter system. The findings highlight a multi-layer and quantitative regulatory method for optimizing the stoichiometric expression of genes in bacteria and promoting the application of SRPS in synthetic biology.
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Affiliation(s)
- Daixi Liu
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
- School of Pharmaceutical Sciences, Shandong University, 44 Wenhuaxi Road, Jinan, Shandong, 250012, China
| | - Haibo Lv
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Yafei Wang
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Jinyu Chen
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Dexin Li
- School of Computer Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Ranran Huang
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
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6
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Pizzolato-Cezar LR, Spira B, Machini MT. Bacterial toxin-antitoxin systems: Novel insights on toxin activation across populations and experimental shortcomings. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 5:100204. [PMID: 38024808 PMCID: PMC10643148 DOI: 10.1016/j.crmicr.2023.100204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Abstract
The alarming rise in hard-to-treat bacterial infections is of great concern to human health. Thus, the identification of molecular mechanisms that enable the survival and growth of pathogens is of utmost urgency for the development of more efficient antimicrobial therapies. In challenging environments, such as presence of antibiotics, or during host infection, metabolic adjustments are essential for microorganism survival and competitiveness. Toxin-antitoxin systems (TASs) consisting of a toxin with metabolic modulating activity and a cognate antitoxin that antagonizes that toxin are important elements in the arsenal of bacterial stress defense. However, the exact physiological function of TA systems is highly debatable and with the exception of stabilization of mobile genetic elements and phage inhibition, other proposed biological functions lack a broad consensus. This review aims at gaining new insights into the physiological effects of TASs in bacteria and exploring the experimental shortcomings that lead to discrepant results in TAS research. Distinct control mechanisms ensure that only subsets of cells within isogenic cultures transiently develop moderate levels of toxin activity. As a result, TASs cause phenotypic growth heterogeneity rather than cell stasis in the entire population. It is this feature that allows bacteria to thrive in diverse environments through the creation of subpopulations with different metabolic rates and stress tolerance programs.
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Affiliation(s)
- Luis R. Pizzolato-Cezar
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Beny Spira
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - M. Teresa Machini
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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7
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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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8
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Kohm K, Jalomo-Khayrova E, Krüger A, Basu S, Steinchen W, Bange G, Frunzke J, Hertel R, Commichau F, Czech L. Structural and functional characterization of MrpR, the master repressor of the Bacillus subtilis prophage SPβ. Nucleic Acids Res 2023; 51:9452-9474. [PMID: 37602373 PMCID: PMC10516654 DOI: 10.1093/nar/gkad675] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 07/11/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023] Open
Abstract
Prophages control their lifestyle to either be maintained within the host genome or enter the lytic cycle. Bacillus subtilis contains the SPβ prophage whose lysogenic state depends on the MrpR (YopR) protein, a key component of the lysis-lysogeny decision system. Using a historic B. subtilis strain harboring the heat-sensitive SPβ c2 mutant, we demonstrate that the lytic cycle of SPβ c2 can be induced by heat due to a single nucleotide exchange in the mrpR gene, rendering the encoded MrpRG136E protein temperature-sensitive. Structural characterization revealed that MrpR is a DNA-binding protein resembling the overall fold of tyrosine recombinases. MrpR has lost its recombinase function and the G136E exchange impairs its higher-order structure and DNA binding activity. Genome-wide profiling of MrpR binding revealed its association with the previously identified SPbeta repeated element (SPBRE) in the SPβ genome. MrpR functions as a master repressor of SPβ that binds to this conserved element to maintain lysogeny. The heat-inducible excision of the SPβ c2 mutant remains reliant on the serine recombinase SprA. A suppressor mutant analysis identified a previously unknown component of the lysis-lysogeny management system that is crucial for the induction of the lytic cycle of SPβ.
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Affiliation(s)
- Katharina Kohm
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany
- FG Molecular Microbiology, Institute for Biology, University of Hohenheim, Stuttgart, Germany
| | - Ekaterina Jalomo-Khayrova
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Phillips-University Marburg, Marburg, Germany
| | - Aileen Krüger
- Institute of Bio- and Geosciences, iBG-1: Biotechnology, FZ Jülich, Germany
| | - Syamantak Basu
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Phillips-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Phillips-University Marburg, Marburg, Germany
- Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Julia Frunzke
- Institute of Bio- and Geosciences, iBG-1: Biotechnology, FZ Jülich, Germany
| | - Robert Hertel
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Göttingen, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany
- FG Molecular Microbiology, Institute for Biology, University of Hohenheim, Stuttgart, Germany
| | - Laura Czech
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Phillips-University Marburg, Marburg, Germany
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9
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Broglia L, Le Rhun A, Charpentier E. Methodologies for bacterial ribonuclease characterization using RNA-seq. FEMS Microbiol Rev 2023; 47:fuad049. [PMID: 37656885 PMCID: PMC10503654 DOI: 10.1093/femsre/fuad049] [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: 03/23/2023] [Revised: 08/06/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
Bacteria adjust gene expression at the post-transcriptional level through an intricate network of small regulatory RNAs and RNA-binding proteins, including ribonucleases (RNases). RNases play an essential role in RNA metabolism, regulating RNA stability, decay, and activation. These enzymes exhibit species-specific effects on gene expression, bacterial physiology, and different strategies of target recognition. Recent advances in high-throughput RNA sequencing (RNA-seq) approaches have provided a better understanding of the roles and modes of action of bacterial RNases. Global studies aiming to identify direct targets of RNases have highlighted the diversity of RNase activity and RNA-based mechanisms of gene expression regulation. Here, we review recent RNA-seq approaches used to study bacterial RNases, with a focus on the methods for identifying direct RNase targets.
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Affiliation(s)
- Laura Broglia
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Center for Human Technologies, Istituto Italiano di Tecnologia, 16152 Genova, Italy
| | - Anaïs Le Rhun
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, F-33000 Bordeaux, France
| | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Institute for Biology, Humboldt University, D-10115 Berlin, Germany
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10
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Trinquier A, Condon C, Braun F. Effect of tRNA Maturase Depletion on Levels and Stabilities of Ribosome Assembly Cofactor and Other mRNAs in Bacillus subtilis. Microbiol Spectr 2023; 11:e0513422. [PMID: 36840557 PMCID: PMC10100781 DOI: 10.1128/spectrum.05134-22] [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: 12/22/2022] [Accepted: 01/30/2023] [Indexed: 02/24/2023] Open
Abstract
The impact of translation on mRNA stability can be varied, ranging from a protective effect of ribosomes that shield mRNA from RNases to preferentially exposing sites of RNase cleavage. These effects can change depending on whether ribosomes are actively moving along the mRNA or stalled at particular sequences or structures or awaiting charged tRNAs. We recently observed that depleting Bacillus subtilis cells of their tRNA maturation enzymes RNase P and RNase Z led to altered mRNA levels of a number of assembly factors involved in the biogenesis of the 30S ribosomal subunit. Here, we extended this study to other assembly factor and non-assembly factor mRNAs in B. subtilis. We additionally identified multiple transcriptional and translational layers of regulation of the rimM operon mRNA that occur in response to the depletion of functional tRNAs. IMPORTANCE The passage of ribosomes across individual mRNAs during translation can have different effects on their degradation, ranging from a protective effect by shielding from ribonucleases to, in some cases, making the mRNA more vulnerable to RNase action. We recently showed that some mRNAs coding for proteins involved in ribosome assembly were highly sensitive to the availability of functional tRNA. Using strains depleted of the major tRNA processing enzymes RNase P and RNase Z, we expanded this observation to a wider set of mRNAs, including some unrelated to ribosome biogenesis. We characterized the impact of tRNA maturase depletion on the rimM operon mRNA and show that it is highly complex, with multiple levels of transcriptional and posttranscriptional effects coming into play.
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Affiliation(s)
- Aude Trinquier
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
| | - Ciarán Condon
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
| | - Frédérique Braun
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
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11
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Zhang J, Hess WR, Zhang C. "Life is short, and art is long": RNA degradation in cyanobacteria and model bacteria. MLIFE 2022; 1:21-39. [PMID: 38818322 PMCID: PMC10989914 DOI: 10.1002/mlf2.12015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/03/2022] [Accepted: 03/03/2022] [Indexed: 06/01/2024]
Abstract
RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes. In bacteria, the mechanisms of RNA turnover have been extensively studied in the models Escherichia coli and Bacillus subtilis, but not much is known in other bacteria. Cyanobacteria are a diverse group of photosynthetic organisms that have great potential for the sustainable production of valuable products using CO2 and solar energy. A better understanding of the regulation of RNA decay is important for both basic and applied studies of cyanobacteria. Genomic analysis shows that cyanobacteria have more than 10 ribonucleases and related proteins in common with E. coli and B. subtilis, and only a limited number of them have been experimentally investigated. In this review, we summarize the current knowledge about these RNA-turnover-related proteins in cyanobacteria. Although many of them are biochemically similar to their counterparts in E. coli and B. subtilis, they appear to have distinct cellular functions, suggesting a different mechanism of RNA turnover regulation in cyanobacteria. The identification of new players involved in the regulation of RNA turnover and the elucidation of their biological functions are among the future challenges in this field.
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Affiliation(s)
- Ju‐Yuan Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of SciencesWuhanChina
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of FreiburgFreiburgGermany
| | - Cheng‐Cai Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of SciencesWuhanChina
- Institut WUT‐AMUAix‐Marseille University and Wuhan University of TechnologyWuhanChina
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12
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Abstract
Toxin-antitoxin systems are widespread in bacterial genomes. They are usually composed of two elements: a toxin that inhibits an essential cellular process and an antitoxin that counteracts its cognate toxin. In the past decade, a number of new toxin-antitoxin systems have been described, bringing new growth inhibition mechanisms to light as well as novel modes of antitoxicity. However, recent advances in the field profoundly questioned the role of these systems in bacterial physiology, stress response and antimicrobial persistence. This shifted the paradigm of the functions of toxin-antitoxin systems to roles related to interactions between hosts and their mobile genetic elements, such as viral defence or plasmid stability. In this Review, we summarize the recent progress in understanding the biology and evolution of these small genetic elements, and discuss how genomic conflicts could shape the diversification of toxin-antitoxin systems.
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13
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RNase III, Ribosome Biogenesis and Beyond. Microorganisms 2021; 9:microorganisms9122608. [PMID: 34946208 PMCID: PMC8708148 DOI: 10.3390/microorganisms9122608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 12/17/2022] Open
Abstract
The ribosome is the universal catalyst for protein synthesis. Despite extensive studies, the diversity of structures and functions of this ribonucleoprotein is yet to be fully understood. Deciphering the biogenesis of the ribosome in a step-by-step manner revealed that this complexity is achieved through a plethora of effectors involved in the maturation and assembly of ribosomal RNAs and proteins. Conserved from bacteria to eukaryotes, double-stranded specific RNase III enzymes play a large role in the regulation of gene expression and the processing of ribosomal RNAs. In this review, we describe the canonical role of RNase III in the biogenesis of the ribosome comparing conserved and unique features from bacteria to eukaryotes. Furthermore, we report additional roles in ribosome biogenesis re-enforcing the importance of RNase III.
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14
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Xu Q, Chen H, Sun W, Zhang Y, Zhu D, Rai KR, Chen JL, Chen Y. sRNA23, a novel small RNA, regulates to the pathogenesis of Streptococcus suis serotype 2. Virulence 2021; 12:3045-3061. [PMID: 34882070 PMCID: PMC8667912 DOI: 10.1080/21505594.2021.2008177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
ABBREVIATION sRNA: small noncoding RNA; FBA: fructose diphosphate aldolase; rplB: 50S ribosomal protein L2; RACE: rapid amplification of cDNA ends; EMSA: electrophoretic mobility shift assay; THB: Todd-Hewitt broth; FBS: fetal bovine serum; BIP: 2,2'-Bipyridine.
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Affiliation(s)
- Quanming Xu
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hong Chen
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wen Sun
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yongyi Zhang
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dewen Zhu
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kul Raj Rai
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ji-Long Chen
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ye Chen
- Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Fujian- Fujian Agriculture and Forestry University, Fuzhou, China
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15
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Svensson SL, Sharma CM. RNase III-mediated processing of a trans-acting bacterial sRNA and its cis-encoded antagonist. eLife 2021; 10:69064. [PMID: 34843430 PMCID: PMC8687705 DOI: 10.7554/elife.69064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 11/28/2021] [Indexed: 12/27/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are important post-transcriptional regulators in stress responses and virulence. They can be derived from an expanding list of genomic contexts, such as processing from parental transcripts by RNase E. The role of RNase III in sRNA biogenesis is less well understood despite its well-known roles in rRNA processing, RNA decay, and cleavage of sRNA-mRNA duplexes. Here, we show that RNase III processes a pair of cis-encoded sRNAs (CJnc190 and CJnc180) of the food-borne pathogen Campylobacter jejuni. While CJnc180 processing by RNase III requires CJnc190, RNase III processes CJnc190 independent of CJnc180 via cleavage of an intramolecular duplex. We also show that CJnc190 directly represses translation of the colonization factor PtmG by targeting a G-rich ribosome-binding site, and uncover that CJnc180 is a cis-acting antagonist of CJnc190, indirectly affecting ptmG regulation. Our study highlights a role for RNase III in sRNA biogenesis and adds cis-encoded RNAs to the expanding diversity of transcripts that can antagonize bacterial sRNAs.
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Affiliation(s)
- Sarah Lauren Svensson
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Cynthia Mira Sharma
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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16
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Brantl S, Müller P. Cis- and Trans-Encoded Small Regulatory RNAs in Bacillus subtilis. Microorganisms 2021; 9:microorganisms9091865. [PMID: 34576762 PMCID: PMC8464778 DOI: 10.3390/microorganisms9091865] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Small regulatory RNAs (sRNAs) that act by base-pairing are the most abundant posttranscriptional regulators in all three kingdoms of life. Over the past 20 years, a variety of approaches have been employed to discover chromosome-encoded sRNAs in a multitude of bacterial species. However, although largely improved bioinformatics tools are available to predict potential targets of base-pairing sRNAs, it is still challenging to confirm these targets experimentally and to elucidate the mechanisms as well as the physiological role of their sRNA-mediated regulation. Here, we provide an overview of currently known cis- and trans-encoded sRNAs from B. subtilis with known targets and defined regulatory mechanisms and on the potential role of RNA chaperones that are or might be required to facilitate sRNA regulation in this important Gram-positive model organism.
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17
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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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18
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Sarpong DD, Murphy ER. RNA Regulated Toxin-Antitoxin Systems in Pathogenic Bacteria. Front Cell Infect Microbiol 2021; 11:661026. [PMID: 34084755 PMCID: PMC8167048 DOI: 10.3389/fcimb.2021.661026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/29/2021] [Indexed: 01/05/2023] Open
Abstract
The dynamic host environment presents a significant hurdle that pathogenic bacteria must overcome to survive and cause diseases. Consequently, these organisms have evolved molecular mechanisms to facilitate adaptation to environmental changes within the infected host. Small RNAs (sRNAs) have been implicated as critical regulators of numerous pathways and systems in pathogenic bacteria, including that of bacterial Toxin-Antitoxin (TA) systems. TA systems are typically composed of two factors, a stable toxin, and a labile antitoxin which functions to protect against the potentially deleterious activity of the associated toxin. Of the six classes of bacterial TA systems characterized to date, the toxin component is always a protein. Type I and Type III TA systems are unique in that the antitoxin in these systems is an RNA molecule, whereas the antitoxin in all other TA systems is a protein. Though hotly debated, the involvement of TA systems in bacterial physiology is recognized by several studies, with the Type II TA system being the most extensively studied to date. This review focuses on RNA-regulated TA systems, highlighting the role of Type I and Type III TA systems in several pathogenic bacteria.
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Affiliation(s)
- David D. Sarpong
- Department of Biological Sciences, Ohio University, Athens, OH, United States
- Infectious and Tropical Diseases Institute, Ohio University, Athens, OH, United States
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, United States
| | - Erin R. Murphy
- Infectious and Tropical Diseases Institute, Ohio University, Athens, OH, United States
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, United States
- Department of Biomedical Sciences, Ohio University, Heritage College of Osteopathic Medicine, Athens, OH, United States
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19
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Siva N, Gupta S, Gupta A, Shukla JN, Malik B, Shukla N. Genome-editing approaches and applications: a brief review on CRISPR technology and its role in cancer. 3 Biotech 2021; 11:146. [PMID: 33732568 PMCID: PMC7910401 DOI: 10.1007/s13205-021-02680-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/05/2021] [Indexed: 02/08/2023] Open
Abstract
The development of genome-editing technologies in 1970s has discerned a new beginning in the field of science. Out of different genome-editing approaches such as Zing-finger nucleases, TALENs, and meganucleases, clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR/Cas9) is a recent and versatile technology that has the ability of making changes to the genome of different organisms with high specificity. Cancer is a complex process that is characterized by multiple genetic and epigenetic changes resulting in abnormal cell growth and proliferation. As cancer is one of the leading causes of deaths worldwide, a large number of studies are done to understand the molecular mechanisms underlying the development of cancer. Because of its high efficiency and specificity, CRISPR/Cas9 has emerged as a novel and powerful tool in the field of cancer research. CRISPR/Cas9 has the potential to accelerate cancer research by dissecting tumorigenesis process, generating animal and cellular models, and identify drug targets for chemotherapeutic approaches. However, despite having tremendous potential, there are certain challenges associated with CRISPR/Cas9 such as safe delivery to the target, potential off-target effects and its efficacy which needs to be addressed prior to its clinical application. In this review, we give a gist of different genome-editing technologies with a special focus on CRISPR/Cas9 development, its mechanism of action and its applications, especially in different type of cancers. We also highlight the importance of CRISPR/Cas9 in generating animal models of different cancers. Finally, we present an overview of the clinical trials and discuss the challenges associated with translating CRISPR/Cas9 in clinical use.
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Affiliation(s)
- Narmadhaa Siva
- Department of Biotechnology and Bioinformatics, Birla Institute of Scientific Research, Statue Circle, Jaipur, India
| | - Sonal Gupta
- Department of Biotechnology and Bioinformatics, Birla Institute of Scientific Research, Statue Circle, Jaipur, India
| | - Ayam Gupta
- Department of Biotechnology and Bioinformatics, Birla Institute of Scientific Research, Statue Circle, Jaipur, India
| | - Jayendra Nath Shukla
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan, Bandarsindari, Ajmer, India
| | - Babita Malik
- Department of Chemistry, Manipal University Jaipur, Jaipur, India
| | - Nidhi Shukla
- Department of Biotechnology and Bioinformatics, Birla Institute of Scientific Research, Statue Circle, Jaipur, India
- Department of Chemistry, Manipal University Jaipur, Jaipur, India
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20
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Samuels DS, Lybecker MC, Yang XF, Ouyang Z, Bourret TJ, Boyle WK, Stevenson B, Drecktrah D, Caimano MJ. Gene Regulation and Transcriptomics. Curr Issues Mol Biol 2020; 42:223-266. [PMID: 33300497 DOI: 10.21775/cimb.042.223] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Borrelia (Borreliella) burgdorferi, along with closely related species, is the etiologic agent of Lyme disease. The spirochete subsists in an enzootic cycle that encompasses acquisition from a vertebrate host to a tick vector and transmission from a tick vector to a vertebrate host. To adapt to its environment and persist in each phase of its enzootic cycle, B. burgdorferi wields three systems to regulate the expression of genes: the RpoN-RpoS alternative sigma factor cascade, the Hk1/Rrp1 two-component system and its product c-di-GMP, and the stringent response mediated by RelBbu and DksA. These regulatory systems respond to enzootic phase-specific signals and are controlled or fine- tuned by transcription factors, including BosR and BadR, as well as small RNAs, including DsrABb and Bb6S RNA. In addition, several other DNA-binding and RNA-binding proteins have been identified, although their functions have not all been defined. Global changes in gene expression revealed by high-throughput transcriptomic studies have elucidated various regulons, albeit technical obstacles have mostly limited this experimental approach to cultivated spirochetes. Regardless, we know that the spirochete, which carries a relatively small genome, regulates the expression of a considerable number of genes required for the transitions between the tick vector and the vertebrate host as well as the adaptation to each.
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Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Meghan C Lybecker
- Department of Biology, University of Colorado, Colorado Springs, CO 80918, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Zhiming Ouyang
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - William K Boyle
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky School of Medicine, Lexington, KY 40536, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
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21
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Ul Haq I, Müller P, Brantl S. Intermolecular Communication in Bacillus subtilis: RNA-RNA, RNA-Protein and Small Protein-Protein Interactions. Front Mol Biosci 2020; 7:178. [PMID: 32850966 PMCID: PMC7430163 DOI: 10.3389/fmolb.2020.00178] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/09/2020] [Indexed: 11/29/2022] Open
Abstract
In bacterial cells we find a variety of interacting macromolecules, among them RNAs and proteins. Not only small regulatory RNAs (sRNAs), but also small proteins have been increasingly recognized as regulators of bacterial gene expression. An average bacterial genome encodes between 200 and 300 sRNAs, but an unknown number of small proteins. sRNAs can be cis- or trans-encoded. Whereas cis-encoded sRNAs interact only with their single completely complementary mRNA target transcribed from the opposite DNA strand, trans-encoded sRNAs are only partially complementary to their numerous mRNA targets, resulting in huge regulatory networks. In addition to sRNAs, uncharged tRNAs can interact with mRNAs in T-box attenuation mechanisms. For a number of sRNA-mRNA interactions, the stability of sRNAs or translatability of mRNAs, RNA chaperones are required. In Gram-negative bacteria, the well-studied abundant RNA-chaperone Hfq fulfils this role, and recently another chaperone, ProQ, has been discovered and analyzed in this respect. By contrast, evidence for RNA chaperones or their role in Gram-positive bacteria is still scarce, but CsrA might be such a candidate. Other RNA-protein interactions involve tmRNA/SmpB, 6S RNA/RNA polymerase, the dual-function aconitase and protein-bound transcriptional terminators and antiterminators. Furthermore, small proteins, often missed in genome annotations and long ignored as potential regulators, can interact with individual regulatory proteins, large protein complexes, RNA or the membrane. Here, we review recent advances on biological role and regulatory principles of the currently known sRNA-mRNA interactions, sRNA-protein interactions and small protein-protein interactions in the Gram-positive model organism Bacillus subtilis. We do not discuss RNases, ribosomal proteins, RNA helicases or riboswitches.
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Affiliation(s)
| | | | - Sabine Brantl
- Matthias-Schleiden-Institut, AG Bakteriengenetik, Friedrich-Schiller-Universität Jena, Jena, Germany
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22
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Tombusvirus p19 Captures RNase III-Cleaved Double-Stranded RNAs Formed by Overlapping Sense and Antisense Transcripts in Escherichia coli. mBio 2020; 11:mBio.00485-20. [PMID: 32518184 PMCID: PMC7373196 DOI: 10.1128/mbio.00485-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Antisense transcription is widespread in bacteria. By base pairing with overlapping sense RNAs, antisense RNAs (asRNA) can form double-stranded RNAs (dsRNA), which are cleaved by RNase III, a dsRNA endoribonuclease. The ectopic expression of plant Tombusvirus p19 in Escherichia coli stabilizes ∼21-nucleotide (nt) dsRNA RNase III decay intermediates, which enabled us to characterize otherwise highly unstable asRNA by deep sequencing of p19-captured dsRNA. RNase III-produced small dsRNA were formed at most bacterial genes in the bacterial genome and in a plasmid. Antisense transcription is widespread in bacteria. By base pairing with overlapping sense RNAs, antisense RNAs (asRNA) can form double-stranded RNAs (dsRNA), which are cleaved by RNase III, a dsRNA endoribonuclease. The ectopic expression of plant Tombusvirus p19 in Escherichia coli stabilizes ∼21-nucleotide (nt) dsRNA RNase III decay intermediates, which enabled us to characterize otherwise highly unstable asRNA by deep sequencing of p19-captured dsRNA. RNase III-produced small dsRNA were formed at most bacterial genes in the bacterial genome and in a plasmid. We classified the types of asRNA in genomic clusters producing the most abundant p19-captured dsRNA and confirmed RNase III regulation of asRNA and sense RNA decay at three type I toxin-antitoxin loci and at a coding gene, rsd. Furthermore, we provide potential evidence for the RNase III-dependent regulation of CspD protein by asRNA. The analysis of p19-captured dsRNA revealed an RNase III sequence preference for AU-rich sequences 3 nucleotides on either side of the cleavage sites and for GC-rich sequences in the 2-nt overhangs. Unexpectedly, GC-rich sequences were enriched in the middle section of p19-captured dsRNA, suggesting some unexpected sequence bias in p19 protein binding. Nonetheless, the ectopic expression of p19 is a sensitive method for identifying antisense transcripts and RNase III cleavage sites in dsRNA formed by overlapping sense and antisense transcripts in bacteria.
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23
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Rath H, Reder A, Hoffmann T, Hammer E, Seubert A, Bremer E, Völker U, Mäder U. Management of Osmoprotectant Uptake Hierarchy in Bacillus subtilis via a SigB-Dependent Antisense RNA. Front Microbiol 2020; 11:622. [PMID: 32373088 PMCID: PMC7186363 DOI: 10.3389/fmicb.2020.00622] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/19/2020] [Indexed: 01/20/2023] Open
Abstract
Under hyperosmotic conditions, bacteria accumulate compatible solutes through synthesis or import. Bacillus subtilis imports a large set of osmostress protectants via five osmotically controlled transport systems (OpuA to OpuE). Biosynthesis of the particularly effective osmoprotectant glycine betaine requires the exogenous supply of choline. While OpuB is rather specific for choline, OpuC imports a broad spectrum of compatible solutes, including choline and glycine betaine. One previously mapped antisense RNA of B. subtilis, S1290, exhibits strong and transient expression in response to a suddenly imposed salt stress. It covers the coding region of the opuB operon and is expressed from a strictly SigB-dependent promoter. By inactivation of this promoter and analysis of opuB and opuC transcript levels, we discovered a time-delayed osmotic induction of opuB that crucially depends on the S1290 antisense RNA and on the degree of the imposed osmotic stress. Time-delayed osmotic induction of opuB is apparently caused by transcriptional interference of RNA-polymerase complexes driving synthesis of the converging opuB and S1290 mRNAs. When our data are viewed in an ecophysiological framework, it appears that during the early adjustment phase of B. subtilis to acute osmotic stress, the cell prefers to initially rely on the transport activity of the promiscuous OpuC system and only subsequently fully induces opuB. Our data also reveal an integration of osmostress-specific adjustment systems with the SigB-controlled general stress response at a deeper level than previously appreciated.
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Affiliation(s)
- Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Elke Hammer
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Analytical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
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24
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Trinquier A, Durand S, Braun F, Condon C. Regulation of RNA processing and degradation in bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194505. [PMID: 32061882 DOI: 10.1016/j.bbagrm.2020.194505] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/13/2020] [Accepted: 02/11/2020] [Indexed: 12/22/2022]
Abstract
Messenger RNA processing and decay is a key mechanism to control gene expression at the post-transcriptional level in response to ever-changing environmental conditions. In this review chapter, we discuss the main ribonucleases involved in these processes in bacteria, with a particular but non-exclusive emphasis on the two best-studied paradigms of Gram-negative and Gram-positive bacteria, E. coli and B. subtilis, respectively. We provide examples of how the activity and specificity of these enzymes can be modulated at the protein level, by co-factor binding and by post-translational modifications, and how they can be influenced by specific properties of their mRNA substrates, such as 5' protective 'caps', nucleotide modifications, secondary structures and translation. This article is part of a Special Issue entitled: RNA and gene control in bacteria edited by Dr. M. Guillier and F. Repoila.
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Affiliation(s)
- Aude Trinquier
- UMR8261 (CNRS, Université de Paris), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Sylvain Durand
- UMR8261 (CNRS, Université de Paris), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Frédérique Braun
- UMR8261 (CNRS, Université de Paris), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Ciarán Condon
- UMR8261 (CNRS, Université de Paris), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
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25
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Adams PP, Storz G. Prevalence of small base-pairing RNAs derived from diverse genomic loci. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194524. [PMID: 32147527 DOI: 10.1016/j.bbagrm.2020.194524] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
Small RNAs (sRNAs) that act by base-pairing have been shown to play important roles in fine-tuning the levels and translation of their target transcripts across a variety of model and pathogenic organisms. Work from many different groups in a wide range of bacterial species has provided evidence for the importance and complexity of sRNA regulatory networks, which allow bacteria to quickly respond to changes in their environment. However, despite the expansive literature, much remains to be learned about all aspects of sRNA-mediated regulation, particularly in bacteria beyond the well-characterized Escherichia coli and Salmonella enterica species. Here we discuss what is known, and what remains to be learned, about the identification of regulatory base-pairing RNAs produced from diverse genomic loci including how their expression is regulated. This article is part of a Special Issue entitled: RNA and gene control in bacteria edited by Dr. M. Guillier and F. Repoila.
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Affiliation(s)
- Philip P Adams
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, USA; Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892-6200, USA.
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, USA
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26
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Drecktrah D, Hall LS, Brinkworth AJ, Comstock JR, Wassarman KM, Samuels DS. Characterization of 6S RNA in the Lyme disease spirochete. Mol Microbiol 2020; 113:399-417. [PMID: 31742773 PMCID: PMC7047579 DOI: 10.1111/mmi.14427] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 11/05/2019] [Accepted: 11/16/2019] [Indexed: 12/31/2022]
Abstract
6S RNA binds to RNA polymerase and regulates gene expression, contributing to bacterial adaptation to environmental stresses. In this study, we examined the role of 6S RNA in murine infectivity and tick persistence of the Lyme disease spirochete Borrelia (Borreliella) burgdorferi. B. burgdorferi 6S RNA (Bb6S RNA) binds to RNA polymerase, is expressed independent of growth phase or nutrient stress in culture, and is processed by RNase Y. We found that rny (bb0504), the gene encoding RNase Y, is essential for B. burgdorferi growth, while ssrS, the gene encoding 6S RNA, is not essential, indicating a broader role for RNase Y activity in the spirochete. Bb6S RNA regulates expression of the ospC and dbpA genes encoding outer surface protein C and decorin binding protein A, respectively, which are lipoproteins important for host infection. The highest levels of Bb6S RNA are found when the spirochete resides in unfed nymphs. ssrS mutants lacking Bb6S RNA were compromised for infectivity by needle inoculation, but injected mice seroconverted, indicating an ability to activate the adaptive immune response. ssrS mutants were successfully acquired by larval ticks and persisted through fed nymphs. Bb6S RNA is one of the first regulatory RNAs identified in B. burgdorferi that controls the expression of lipoproteins involved in host infectivity.
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Affiliation(s)
- Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Laura S. Hall
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | | | | | - Karen M. Wassarman
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - D. Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
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27
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Liu X, Zhang Y, Liu H, Jiao X, Zhang Q, Zhang S, Zhao ZK. RNA interference in the oleaginous yeast Rhodosporidium toruloides. FEMS Yeast Res 2019; 19:5462653. [PMID: 30985887 DOI: 10.1093/femsyr/foz031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/13/2019] [Indexed: 01/21/2023] Open
Abstract
The red yeast Rhodosporidium toruloides is an excellent microbial host for production of carotenoids, neutral lipids and valuable enzymes. In recent years, genetic tools for gene expression and gene disruption have been developed for this red yeast. However, methods remain limited in terms of fine-tuning gene expression. In this study, we first demonstrated successful implementation of RNA interference (RNAi) in R. toruloides NP11, which was applied to down-regulate the expression of autophagy related gene 8 (ATG8), and fatty acid synthase genes (FAS1 and FAS2), respectively. Compared with the control strain, RNAi-engineered strains showed a silencing efficiency ranging from 11% to 92%. The RNAi approach described here ensures selective inhibition of the target gene expression, and should expand our capacity in the genetic manipulation of R. toruloides for both fundamental research and advanced cell factory development.
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Affiliation(s)
- Xiangjian Liu
- School of Biological Engineering, Dalian Polytechnic University, Dalian 116034, PR China.,Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
| | - Yue Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China.,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Hongdi Liu
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
| | - Xiang Jiao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
| | - Qi Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
| | - Sufang Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
| | - Zongbao Kent Zhao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China
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28
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Unlinked rRNA genes are widespread among bacteria and archaea. ISME JOURNAL 2019; 14:597-608. [PMID: 31712737 DOI: 10.1038/s41396-019-0552-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/23/2019] [Accepted: 10/29/2019] [Indexed: 02/06/2023]
Abstract
Ribosomes are essential to cellular life and the genes for their RNA components are the most conserved and transcribed genes in bacteria and archaea. Ribosomal RNA genes are typically organized into a single operon, an arrangement thought to facilitate gene regulation. In reality, some bacteria and archaea do not share this canonical rRNA arrangement-their 16S and 23S rRNA genes are separated across the genome and referred to as "unlinked". This rearrangement has previously been treated as an anomaly or a byproduct of genome degradation in intracellular bacteria. Here, we leverage complete genome and long-read metagenomic data to show that unlinked 16S and 23S rRNA genes are more common than previously thought. Unlinked rRNA genes occur in many phyla, most significantly within Deinococcus-Thermus, Chloroflexi, and Planctomycetes, and occur in differential frequencies across natural environments. We found that up to 41% of rRNA genes in soil were unlinked, in contrast to the human gut, where all sequenced rRNA genes were linked. The frequency of unlinked rRNA genes may reflect meaningful life history traits, as they tend to be associated with a mix of slow-growing free-living species and intracellular species. We speculate that unlinked rRNA genes may confer selective advantages in some environments, though the specific nature of these advantages remains undetermined and worthy of further investigation. More generally, the prevalence of unlinked rRNA genes in poorly-studied taxa serves as a reminder that paradigms derived from model organisms do not necessarily extend to the broader diversity of bacteria and archaea.
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29
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Maikova A, Peltier J, Boudry P, Hajnsdorf E, Kint N, Monot M, Poquet I, Martin-Verstraete I, Dupuy B, Soutourina O. Discovery of new type I toxin-antitoxin systems adjacent to CRISPR arrays in Clostridium difficile. Nucleic Acids Res 2019. [PMID: 29529286 PMCID: PMC5961336 DOI: 10.1093/nar/gky124] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clostridium difficile, a major human enteropathogen, must cope with foreign DNA invaders and multiple stress factors inside the host. We have recently provided an experimental evidence of defensive function of the C. difficile CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system important for its survival within phage-rich gut communities. Here, we describe the identification of type I toxin-antitoxin (TA) systems with the first functional antisense RNAs in this pathogen. Through the analysis of deep-sequencing data, we demonstrate the general co-localization with CRISPR arrays for the majority of sequenced C. difficile strains. We provide a detailed characterization of the overlapping convergent transcripts for three selected TA pairs. The toxic nature of small membrane proteins is demonstrated by the growth arrest induced by their overexpression. The co-expression of antisense RNA acting as an antitoxin prevented this growth defect. Co-regulation of CRISPR-Cas and type I TA genes by the general stress response Sigma B and biofilm-related factors further suggests a possible link between these systems with a role in recurrent C. difficile infections. Our results provide the first description of genomic links between CRISPR and type I TA systems within defense islands in line with recently emerged concept of functional coupling of immunity and cell dormancy systems in prokaryotes.
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Affiliation(s)
- Anna Maikova
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251, Russia
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Pierre Boudry
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Eliane Hajnsdorf
- UMR8261 (CNRS-Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Nicolas Kint
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Marc Monot
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, J1E 4K8, Sherbrooke, QC, Canada
| | - Isabelle Poquet
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,INRA, UMR1319 Micalis (Microbiologie de l'Alimentation au service de la Santé), Domaine de Vilvert, 78352, Jouy-en-Josas Cedex, France
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Olga Soutourina
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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30
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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: 109] [Impact Index Per Article: 21.8] [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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31
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Brantl S, Müller P. Toxin⁻Antitoxin Systems in Bacillus subtilis. Toxins (Basel) 2019; 11:toxins11050262. [PMID: 31075979 PMCID: PMC6562991 DOI: 10.3390/toxins11050262] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 12/31/2022] Open
Abstract
Toxin-antitoxin (TA) systems were originally discovered as plasmid maintenance systems in a multitude of free-living bacteria, but were afterwards found to also be widespread in bacterial chromosomes. TA loci comprise two genes, one coding for a stable toxin whose overexpression kills the cell or causes growth stasis, and the other coding for an unstable antitoxin that counteracts toxin action. Of the currently known six types of TA systems, in Bacillus subtilis, so far only type I and type II TA systems were found, all encoded on the chromosome. Here, we review our present knowledge of these systems, the mechanisms of antitoxin and toxin action, and the regulation of their expression, and we discuss their evolution and possible physiological role.
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Affiliation(s)
- Sabine Brantl
- Friedrich-Schiller-Universität Jena, Matthias-Schleiden-Institut, AG Bakteriengenetik, Philosophenweg 12, D-07743 Jena, Germany.
| | - Peter Müller
- Friedrich-Schiller-Universität Jena, Matthias-Schleiden-Institut, AG Bakteriengenetik, Philosophenweg 12, D-07743 Jena, Germany.
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32
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Soutourina O. Type I Toxin-Antitoxin Systems in Clostridia. Toxins (Basel) 2019; 11:toxins11050253. [PMID: 31064056 PMCID: PMC6563280 DOI: 10.3390/toxins11050253] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 04/30/2019] [Accepted: 05/02/2019] [Indexed: 12/20/2022] Open
Abstract
Type I toxin-antitoxin (TA) modules are abundant in both bacterial plasmids and chromosomes and usually encode a small hydrophobic toxic protein and an antisense RNA acting as an antitoxin. The RNA antitoxin neutralizes toxin mRNA by inhibiting its translation and/or promoting its degradation. This review summarizes our current knowledge of the type I TA modules identified in Clostridia species focusing on the recent findings in the human pathogen Clostridium difficile. More than ten functional type I TA modules have been identified in the genome of this emerging enteropathogen that could potentially contribute to its fitness and success inside the host. Despite the absence of sequence homology, the comparison of these newly identified type I TA modules with previously studied systems in other Gram-positive bacteria, i.e., Bacillus subtilis and Staphylococcus aureus, revealed some important common traits. These include the conservation of characteristic sequence features for small hydrophobic toxic proteins, the localization of several type I TA within prophage or prophage-like regions and strong connections with stress response. Potential functions in the stabilization of genome regions, adaptations to stress conditions and interactions with CRISPR-Cas defence system, as well as promising applications of TA for genome-editing and antimicrobial developments are discussed.
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Affiliation(s)
- Olga Soutourina
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
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33
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Trinquier A, Ulmer JE, Gilet L, Figaro S, Hammann P, Kuhn L, Braun F, Condon C. tRNA Maturation Defects Lead to Inhibition of rRNA Processing via Synthesis of pppGpp. Mol Cell 2019; 74:1227-1238.e3. [PMID: 31003868 DOI: 10.1016/j.molcel.2019.03.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/07/2019] [Accepted: 03/24/2019] [Indexed: 02/03/2023]
Abstract
rRNAs and tRNAs universally require processing from longer primary transcripts to become functional for translation. Here, we describe an unsuspected link between tRNA maturation and the 3' processing of 16S rRNA, a key step in preparing the small ribosomal subunit for interaction with the Shine-Dalgarno sequence in prokaryotic translation initiation. We show that an accumulation of either 5' or 3' immature tRNAs triggers RelA-dependent production of the stringent response alarmone (p)ppGpp in the Gram-positive model organism Bacillus subtilis. The accumulation of (p)ppGpp and accompanying decrease in GTP levels specifically inhibit 16S rRNA 3' maturation. We suggest that cells can exploit this mechanism to sense potential slowdowns in tRNA maturation and adjust rRNA processing accordingly to maintain the appropriate functional balance between these two major components of the translation apparatus.
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MESH Headings
- Bacillus subtilis/genetics
- Bacillus subtilis/metabolism
- Base Sequence
- Gene Expression Regulation, Bacterial
- Guanosine Pentaphosphate/biosynthesis
- Guanosine Pentaphosphate/genetics
- Guanosine Triphosphate/metabolism
- Ligases/genetics
- Ligases/metabolism
- Nucleic Acid Conformation
- Peptide Chain Initiation, Translational
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Ribosome Subunits, Large, Bacterial/genetics
- Ribosome Subunits, Large, Bacterial/metabolism
- Ribosome Subunits, Small, Bacterial/genetics
- Ribosome Subunits, Small, Bacterial/metabolism
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Affiliation(s)
- Aude Trinquier
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Jonathan E Ulmer
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Laetitia Gilet
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Sabine Figaro
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS FR1589, 15 rue Descartes, 67084 Strasbourg Cedex, France
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS FR1589, 15 rue Descartes, 67084 Strasbourg Cedex, France
| | - Frédérique Braun
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Ciarán Condon
- UMR8261 (CNRS-Université Paris Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
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34
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Type I Toxin-Antitoxin Systems: Regulating Toxin Expression via Shine-Dalgarno Sequence Sequestration and Small RNA Binding. Microbiol Spectr 2019; 6. [PMID: 30051800 DOI: 10.1128/microbiolspec.rwr-0030-2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toxin-antitoxin (TA) systems are small genetic loci composed of two adjacent genes: a toxin and an antitoxin that prevents toxin action. Despite their wide distribution in bacterial genomes, the reasons for TA systems being on chromosomes remain enigmatic. In this review, we focus on type I TA systems, composed of a small antisense RNA that plays the role of an antitoxin to control the expression of its toxin counterpart. It does so by direct base-pairing to the toxin-encoding mRNA, thereby inhibiting its translation and/or promoting its degradation. However, in many cases, antitoxin binding is not sufficient to avoid toxicity. Several cis-encoded mRNA elements are also required for repression, acting to uncouple transcription and translation via the sequestration of the ribosome binding site. Therefore, both antisense RNA binding and compact mRNA folding are necessary to tightly control toxin synthesis and allow the presence of these toxin-encoding systems on bacterial chromosomes.
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35
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Abstract
ABSTRACT
Although bacterial genomes are usually densely protein-coding, genome-wide mapping approaches of transcriptional start sites revealed that a significant fraction of the identified promoters drive the transcription of noncoding RNAs. These can be
trans
-acting RNAs, mainly originating from intergenic regions and, in many studied examples, possessing regulatory functions. However, a significant fraction of these noncoding RNAs consist of natural antisense transcripts (asRNAs), which overlap other transcriptional units. Naturally occurring asRNAs were first observed to play a role in bacterial plasmid replication and in bacteriophage λ more than 30 years ago. Today’s view is that asRNAs abound in all three domains of life. There are several examples of asRNAs in bacteria with clearly defined functions. Nevertheless, many asRNAs appear to result from pervasive initiation of transcription, and some data point toward global functions of such widespread transcriptional activity, explaining why the search for a specific regulatory role is sometimes futile. In this review, we give an overview about the occurrence of antisense transcription in bacteria, highlight particular examples of functionally characterized asRNAs, and discuss recent evidence pointing at global relevance in RNA processing and transcription-coupled DNA repair.
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36
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Anacker ML, Drecktrah D, LeCoultre RD, Lybecker M, Samuels DS. RNase III Processing of rRNA in the Lyme Disease Spirochete Borrelia burgdorferi. J Bacteriol 2018; 200:e00035-18. [PMID: 29632096 PMCID: PMC5996687 DOI: 10.1128/jb.00035-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/04/2018] [Indexed: 02/08/2023] Open
Abstract
The rRNA genes of Borrelia (Borreliella) burgdorferi are unusually organized; the spirochete has a single 16S rRNA gene that is more than 3 kb from a tandem pair of 23S-5S rRNA operons. We generated an rnc null mutant in B. burgdorferi that exhibits a pleiotropic phenotype, including decreased growth rate and increased cell length. Here, we demonstrate that endoribonuclease III (RNase III) is, as expected, involved in processing the 23S rRNA in B. burgdorferi The 5' and 3' ends of the three rRNAs were determined in the wild type and rncBb mutants; the results suggest that RNase III in B. burgdorferi is required for the full maturation of the 23S rRNA but not for the 5S rRNA nor, curiously, for the 16S rRNA.IMPORTANCE Lyme disease, the most common tick-borne zoonosis in the Northern Hemisphere, is caused by the bacterium Borrelia (Borreliella) burgdorferi, a member of the deeply branching spirochete phylum. B. burgdorferi carries a limited suite of ribonucleases, enzymes that cleave RNA during processing and degradation. Several ribonucleases, including RNase III, are involved in the production of ribosomes, which catalyze translation and are a major target of antibiotics. This is the first study to dissect the role of an RNase in any spirochete. We demonstrate that an RNase III mutant is viable but has altered processing of rRNA.
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MESH Headings
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Borrelia burgdorferi/enzymology
- Borrelia burgdorferi/genetics
- Borrelia burgdorferi/metabolism
- Humans
- Lyme Disease/microbiology
- Operon
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/metabolism
- RNA, Ribosomal, 5S/genetics
- RNA, Ribosomal, 5S/metabolism
- Ribonuclease III/genetics
- Ribonuclease III/metabolism
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Affiliation(s)
- Melissa L Anacker
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Richard D LeCoultre
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Meghan Lybecker
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Department of Biology, University of Colorado, Colorado Springs, Colorado, USA
| | - D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, USA
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37
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Maeda T, Tanaka Y, Inui M. Glutamine-rich toxic proteins GrtA, GrtB and GrtC together with the antisense RNA AsgR constitute a toxin-antitoxin-like system in Corynebacterium glutamicum. Mol Microbiol 2018. [PMID: 29537126 DOI: 10.1111/mmi.13951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Corynebacterium glutamicum R grtA (cgR_2936), grtB (cgR_2934) and grtC (cgR_2933) genes were identified as paralogs encoding glutamine-rich toxic proteins. We also identified a new antisense small RNA AsgR (antisense sRNA for grtA) that overlaps the 3' end of the grtA gene. Single over-expressions of grtA, grtB and grtC resulted in complete inhibition of Escherichia coli cell growth. This growth was rescued by co-expression of AsgR. Similar effects were observed in C. glutamicum, although the toxicities of these proteins were moderate. Inhibition of AsgR transcription resulted in increased levels and prolonged half-lives of grtA, grtB and grtC mRNAs. We also found that the expression levels of grtA, grtB and grtC were increased in an RNase III deletion mutant. Primer extension analysis revealed the RNase III cleavage site to be in the 3' untranslated region (3'-UTR) of the grtA mRNA. The expression levels of grtA, grtB and grtC were increased after exposure to several stresses, including heat shock, treatment with penicillin G, lysozyme or H2 O2 . The deletions of grtABC and asgR genes resulted in decreased survival rate under several stresses. These results indicate that GrtABC and AsgR constitute a type I toxin-antitoxin-like system in C. glutamicum.
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Affiliation(s)
- Tomoya Maeda
- Research Institute of Innovative Technology for the Earth, Kyoto, Japan
| | - Yuya Tanaka
- Research Institute of Innovative Technology for the Earth, Kyoto, Japan
| | - Masayuki Inui
- Research Institute of Innovative Technology for the Earth, Kyoto, Japan.,Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
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38
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Gordon GC, Cameron JC, Pfleger BF. Distinct and redundant functions of three homologs of RNase III in the cyanobacterium Synechococcus sp. strain PCC 7002. Nucleic Acids Res 2018; 46:1984-1997. [PMID: 29373746 PMCID: PMC5829567 DOI: 10.1093/nar/gky041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/11/2018] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
RNase III is a ribonuclease that recognizes and cleaves double-stranded RNA. Across bacteria, RNase III is involved in rRNA maturation, CRISPR RNA maturation, controlling gene expression, and turnover of messenger RNAs. Many organisms have only one RNase III while others have both a full-length RNase III and another version that lacks a double-stranded RNA binding domain (mini-III). The genome of the cyanobacterium Synechococcus sp. strain PCC 7002 (PCC 7002) encodes three homologs of RNase III, two full-length and one mini-III, that are not essential even when deleted in combination. To discern if each enzyme had distinct responsibilities, we collected and sequenced global RNA samples from the wild type strain, the single, double, and triple RNase III mutants. Approximately 20% of genes were differentially expressed in various mutants with some operons and regulons showing complex changes in expression levels between mutants. Two RNase III's had a role in 23S rRNA maturation and the third was involved in copy number regulation one of six native plasmids. In vitro, purified RNase III enzymes were capable of cleaving some of the known Escherichia coli RNase III target sequences, highlighting the remarkably conserved substrate specificity between organisms yet complex regulation of gene expression.
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Affiliation(s)
- Gina C Gordon
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jeffrey C Cameron
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
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39
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Reif C, Löser C, Brantl S. Bacillus subtilis Type I antitoxin SR6 Promotes Degradation of Toxin yonT mRNA and Is Required to Prevent Toxic yoyJ Overexpression. Toxins (Basel) 2018; 10:toxins10020074. [PMID: 29414903 PMCID: PMC5848175 DOI: 10.3390/toxins10020074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 01/30/2018] [Accepted: 02/04/2018] [Indexed: 11/19/2022] Open
Abstract
yonT/SR6 is the second type I toxin-antitoxin (TA) system encoded on prophage SPβ in the B. subtilis chromosome. The yonT ORF specifying a 58 aa toxin is transcribed on a polycistronic mRNA under control of the yonT promoter. The antitoxin SR6 is a 100 nt antisense RNA that overlaps yonT at its 3′ end and the downstream gene yoyJ encoding a second, much weaker, toxin at its 5′ end. SR6 displays a half-life of >60 min, whereas yonT mRNA is less stable with a half-life of ≈8 min. SR6 is in significant excess over yonT mRNA except in minimal medium with glucose. It interacts with the 3′ UTR of yonT mRNA, thereby promoting its degradation by RNase III. By contrast, SR6 does not affect the amount or half-life of yoyJ mRNA. However, in its absence, a yoyJ overexpression plasmid could not be established in Bacillus subtilis suggesting that SR6 inhibits yoyJ translation by directly binding to its ribosome-binding site. While the amounts of both yonT RNA and SR6 were affected by vancomycin, manganese, heat-shock and ethanol stress as well as iron limitation, oxygen stress decreased only the amount of SR6.
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Affiliation(s)
- Celine Reif
- Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, D-07743 Jena, Germany.
| | - Charlotte Löser
- Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, D-07743 Jena, Germany.
| | - Sabine Brantl
- Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, D-07743 Jena, Germany.
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40
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Aguado LC, tenOever BR. RNase III Nucleases and the Evolution of Antiviral Systems. Bioessays 2017; 40. [PMID: 29266287 DOI: 10.1002/bies.201700173] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/26/2017] [Indexed: 01/15/2023]
Abstract
Every living entity requires the capacity to defend against viruses in some form. From bacteria to plants to arthropods, cells retain the capacity to capture genetic material, process it in a variety of ways, and subsequently use it to generate pathogen-specific small RNAs. These small RNAs can then be used to provide specificity to an otherwise non-specific nuclease, generating a potent antiviral system. While small RNA-based defenses in chordates are less utilized, the protein-based antiviral invention in this phylum appears to have derived from components of the same ancestral small RNA machinery. Based on recent evidence, it would seem that RNase III nucleases have been reiteratively repurposed over billions of years to provide cells with the capacity to recognize and destroy unwanted genetic material. Here we describe an overview of what is known on this subject and provide a model for how these defenses may have evolved.
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Affiliation(s)
- Lauren C Aguado
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, 10029, New York, USA
| | - Benjamin R tenOever
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, 10029, New York, USA
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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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Arnion H, Korkut DN, Masachis Gelo S, Chabas S, Reignier J, Iost I, Darfeuille F. Mechanistic insights into type I toxin antitoxin systems in Helicobacter pylori: the importance of mRNA folding in controlling toxin expression. Nucleic Acids Res 2017; 45:4782-4795. [PMID: 28077560 PMCID: PMC5416894 DOI: 10.1093/nar/gkw1343] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 12/22/2016] [Indexed: 12/16/2022] Open
Abstract
Type I toxin-antitoxin (TA) systems have been identified in a wide range of bacterial genomes. Here, we report the characterization of a new type I TA system present on the chromosome of the major human gastric pathogen, Helicobacter pylori. We show that the aapA1 gene encodes a 30 amino acid peptide whose artificial expression in H. pylori induces cell death. The synthesis of this toxin is prevented by the transcription of an antitoxin RNA, named IsoA1, expressed on the opposite strand of the toxin gene. We further reveal additional layers of post-transcriptional regulation that control toxin expression: (i) transcription of the aapA1 gene generates a full-length transcript whose folding impedes translation (ii) a 3΄ end processing of this message generates a shorter transcript that, after a structural rearrangement, becomes translatable (iii) but this rearrangement also leads to the formation of two stem-loop structures allowing formation of an extended duplex with IsoA1 via kissing-loop interactions. This interaction ensures both the translation inhibition of the AapA1 active message and its rapid degradation by RNase III, thus preventing toxin synthesis under normal growth conditions. Finally, a search for homologous mRNA structures identifies similar TA systems in a large number of Helicobacter and Campylobacter genomes.
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Affiliation(s)
- Hélène Arnion
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Dursun Nizam Korkut
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Sara Masachis Gelo
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Sandrine Chabas
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Jérémy Reignier
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Isabelle Iost
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Fabien Darfeuille
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
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Wen J, Harp JR, Fozo EM. The 5΄ UTR of the type I toxin ZorO can both inhibit and enhance translation. Nucleic Acids Res 2017; 45:4006-4020. [PMID: 27903909 PMCID: PMC5397157 DOI: 10.1093/nar/gkw1172] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/14/2016] [Indexed: 01/30/2023] Open
Abstract
Many bacterial type I toxin mRNAs possess a long 5΄ untranslated region (UTR) that serves as the target site of the corresponding antitoxin sRNA. This is the case for the zorO-orzO type I system where the OrzO antitoxin base pairs to the 174-nucleotide zorO 5΄ UTR. Here, we demonstrate that the full-length 5΄ UTR of the zorO type I toxin hinders its own translation independent of the sRNA whereas a processed 5΄ UTR (zorO Δ28) promotes translation. The full-length zorO 5΄ UTR folds into an extensive secondary structure sequestering the ribosome binding site (RBS). Processing of the 5΄ UTR does not alter the RBS structure, but opens a large region (EAP region) located upstream of the RBS. Truncation of this EAP region impairs zorO translation, but this defect can be rescued upon exposing the RBS. Additionally, the region spanning +35 to +50 of the zorO mRNA is needed for optimal translation of zorO. Importantly, the positive and negative effects on translation imparted by the 5΄ UTR can be transferred onto a reporter gene, indicative that the 5΄ UTR can solely drive regulation. Moreover, we show that the OrzO sRNA can inhibit zorO translation via base pairing to the of the EAP region.
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Affiliation(s)
- Jia Wen
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - John R Harp
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
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Small RNA mediated repression of subtilisin production in Bacillus licheniformis. Sci Rep 2017; 7:5699. [PMID: 28720814 PMCID: PMC5516005 DOI: 10.1038/s41598-017-05628-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/31/2017] [Indexed: 01/08/2023] Open
Abstract
The species Bacillus licheniformis includes important strains that are used in industrial production processes. Currently the physiological model used to adapt these processes is based on the closely related model organism B. subtilis. In this study we found that both organisms reveal significant differences in the regulation of subtilisin, their main natural protease and a product of industrial fermentation processes. We identified and characterized a novel antisense sRNA AprAs, which represents an RNA based repressor of apr, the gene encoding for the industrial relevant subtilisin protease. Reduction of the AprAs level leads to an enhanced proteolytic activity and an increase of Apr protein expression in the mutant strain. A vector based complementation of the AprAs deficient mutant confirmed this effect and demonstrated the necessity of cis transcription for full efficiency. A comparative analysis of the corresponding genome loci from B. licheniformis and B. subtilis revealed the absence of an aprAs promoter in B. subtilis and indicates that AprAs is a B. licheniformis species specific phenomenon. The discovery of AprAs is of great biotechnological interest since subtilisin Carlsberg is one of the main products of industrial fermentation by B. licheniformis.
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Abstract
Bacterial pathogens must endure or adapt to different environments and stresses during transmission and infection. Posttranscriptional gene expression control by regulatory RNAs, such as small RNAs and riboswitches, is now considered central to adaptation in many bacteria, including pathogens. The study of RNA-based regulation (riboregulation) in pathogenic species has provided novel insight into how these bacteria regulate virulence gene expression. It has also uncovered diverse mechanisms by which bacterial small RNAs, in general, globally control gene expression. Riboregulators as well as their targets may also prove to be alternative targets or provide new strategies for antimicrobials. In this article, we present an overview of the general mechanisms that bacteria use to regulate with RNA, focusing on examples from pathogens. In addition, we also briefly review how deep sequencing approaches have aided in opening new perspectives in small RNA identification and the study of their functions. Finally, we discuss examples of riboregulators in two model pathogens that control virulence factor expression or survival-associated phenotypes, such as stress tolerance, biofilm formation, or cell-cell communication, to illustrate how riboregulation factors into regulatory networks in bacterial pathogens.
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Enzymatic activity necessary to restore the lethality due to Escherichia coli RNase E deficiency is distributed among bacteria lacking RNase E homologues. PLoS One 2017; 12:e0177915. [PMID: 28542621 PMCID: PMC5436854 DOI: 10.1371/journal.pone.0177915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/05/2017] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli RNase E (Eco-RNase E), encoded by rne (Eco-rne), is considered the global RNA decay initiator. Although Eco-RNase E is an essential gene product in E. coli, some bacterial species, such as Bacillus subtilis, do not possess Eco-RNase E sequence homologues. B. subtilis instead possesses RNase J1/J2 (Bsu-RNase J1/J2) and RNase Y (Bsu-RNase Y) to execute RNA decay. Here we found that E. coli lacking the Eco-rne gene (Δrne E. coli) was viable conditional on M9 minimal media by introducing Bsu-RNase J1/J2 or Bsu-RNase Y. We also cloned an extremely short Eco-RNase E homologue (Wpi-RNase E) and a canonical sized Bsu-RNase J1/J2 homologue (Wpi-RNase J) from Wolbachia pipientis, an α-proteobacterial endosymbiont of arthropods. We found that Wpi-RNase J restored the colony-forming ability (CFA) of Δrne E. coli, whereas Wpi-RNase E did not. Unexpectedly, Wpi-RNase E restored defective CFA due to lack of Eco-RNase G, a paralogue of Eco-RNase E. Our results indicate that bacterial species that lack Eco-RNase E homologues or bacterial species that possess Eco-RNase E homologues which lack Eco-RNase E-like activities have a modest Eco-RNase E-like function using RNase J and/or RNase Y. These results suggest that Eco-RNase E-like activities might distribute among a wide array of bacteria and that functions of RNases may have changed dynamically during evolutionary divergence of bacterial lineages.
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Lu W, Xin Z, Shida W, Jiyao L, Xin X. [Role of small noncoding RNA in the regulation of bacterial virulence]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2017; 34:433-438. [PMID: 28317367 DOI: 10.7518/hxkq.2016.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the long-term interaction between pathogens and host, the pathogens regulate the expression of related viru-lence genes to fit the host environment in response to the changes in the host microenvironment. Gene expression was believed to be controlled mainly at the level of transcription initiation by repressors or activators. Recent studies have revealed that small noncoding RNAs (sRNAs) are key regulators in bacterial pathogenesis. sRNA in bacteria is a noncoding RNA with length ranging from 50 to 500 nucleotides. Pathogens can sense the changes in the host environment and consequently regulate the expression of virulence genes by sRNAs. This condition promotes the ability of pathogens to survive within the host, which is beneficial to the invasion and pathogenicity of pathogens. In contrast to transcriptional factors, sRNA-mediated gene regu-lation makes rapid and sensitive responses to environmental cues. Many sRNAs involved in bacterial virulence and pathogenesis have been identified. These sRNAs are key components of coordinated regulation networks, playing important roles in regulating the expression of virulence genes at post-transcriptional level. This review aims to provide an overview on the molecular mechanisms and roles of sRNAs in the regulation of bacterial virulence.
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Affiliation(s)
- Wang Lu
- State Key Laboratory of Oral Diseases, Dept. of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zheng Xin
- State Key Laboratory of Oral Diseases, Dept. of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Wang Shida
- State Key Laboratory of Oral Diseases, Dept. of General Clinic, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Li Jiyao
- State Key Laboratory of Oral Diseases, Dept. of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Xu Xin
- State Key Laboratory of Oral Diseases, Dept. of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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RNA Sequencing Identifies New RNase III Cleavage Sites in Escherichia coli and Reveals Increased Regulation of mRNA. mBio 2017; 8:mBio.00128-17. [PMID: 28351917 PMCID: PMC5371410 DOI: 10.1128/mbio.00128-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ribonucleases facilitate rapid turnover of RNA, providing cells with another mechanism to adjust transcript and protein levels in response to environmental conditions. While many examples have been documented, a comprehensive list of RNase targets is not available. To address this knowledge gap, we compared levels of RNA sequencing coverage of Escherichia coli and a corresponding RNase III mutant to expand the list of known RNase III targets. RNase III is a widespread endoribonuclease that binds and cleaves double-stranded RNA in many critical transcripts. RNase III cleavage at novel sites found in aceEF, proP, tnaC, dctA, pheM, sdhC, yhhQ, glpT, aceK, and gluQ accelerated RNA decay, consistent with previously described targets wherein RNase III cleavage initiates rapid degradation of secondary messages by other RNases. In contrast, cleavage at three novel sites in the ahpF, pflB, and yajQ transcripts led to stabilized secondary transcripts. Two other novel sites in hisL and pheM overlapped with transcriptional attenuators that likely serve to ensure turnover of these highly structured RNAs. Many of the new RNase III target sites are located on transcripts encoding metabolic enzymes. For instance, two novel RNase III sites are located within transcripts encoding enzymes near a key metabolic node connecting glycolysis and the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase activity was increased in an rnc deletion mutant compared to the wild-type (WT) strain in early stationary phase, confirming the novel link between RNA turnover and regulation of pathway activity. Identification of these novel sites suggests that mRNA turnover may be an underappreciated mode of regulating metabolism. The concerted action and overlapping functions of endoribonucleases, exoribonucleases, and RNA processing enzymes complicate the study of global RNA turnover and recycling of specific transcripts. More information about RNase specificity and activity is needed to make predictions of transcript half-life and to design synthetic transcripts with optimal stability. RNase III does not have a conserved target sequence but instead recognizes RNA secondary structure. Prior to this study, only a few RNase III target sites in E. coli were known, so we used RNA sequencing to provide a more comprehensive list of cleavage sites and to examine the impact of RNase III on transcript degradation. With this added information on how RNase III participates in transcript regulation and recycling, a more complete picture of RNA turnover can be developed for E. coli. Similar approaches could be used to augment our understanding of RNA turnover in other bacteria.
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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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Abstract
Gene organization and control are described by models conceived in the 1960s. These models explain basic gene regulatory mechanisms and underpin current genome annotation. However, such models struggle to explain recent genome-scale observations. For example, accounts of RNA synthesis initiating within genes, widespread antisense transcription and non-canonical DNA binding by gene regulatory proteins are difficult to reconcile with traditional thinking. As a result, unexpected observations have often been dismissed and downstream consequences ignored. In this paper I will argue that, to fully understand the biology of bacterial chromosomes, we must embrace their hidden layers of complexity.
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Affiliation(s)
- David C Grainger
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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