101
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Raina M, King A, Bianco C, Vanderpool CK. Dual-Function RNAs. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0032-2018. [PMID: 30191807 PMCID: PMC6130917 DOI: 10.1128/microbiolspec.rwr-0032-2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Indexed: 12/30/2022] Open
Abstract
Bacteria are known to use RNA, either as mRNAs encoding proteins or as noncoding small RNAs (sRNAs), to regulate numerous biological processes. However, a few sRNAs have two functions: they act as base-pairing RNAs and encode a small protein with additional regulatory functions. Thus, these so called "dual-function" sRNAs can serve as both a riboregulator and an mRNA. In some cases, these two functions can act independently within the same pathway, while in other cases, the base-pairing function and protein function act in different pathways. Here, we discuss the five known dual-function sRNAs-SgrS from enteric species, RNAIII and Psm-mec from Staphylococcus aureus, Pel RNA from Streptococcus pyogenes, and SR1 from Bacillus subtilis-and review their mechanisms of action and roles in regulating diverse biological processes. We also discuss the prospect of finding additional dual-function sRNAs and future challenges in studying the overlap and competition between the functions.
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Affiliation(s)
- Medha Raina
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Alisa King
- Department of Microbiology, University of Illinois, Urbana, IL 61801
| | - Colleen Bianco
- Department of Microbiology, University of Illinois, Urbana, IL 61801
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102
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Asmar AT, Collet JF. Lpp, the Braun lipoprotein, turns 50—major achievements and remaining issues. FEMS Microbiol Lett 2018; 365:5071948. [DOI: 10.1093/femsle/fny199] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/10/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Abir T Asmar
- WELBIO, Université catholique de Louvain, avenue Hippocrate 75, Brussels 1200, Belgium
- De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Brussels 1200, Belgium
| | - Jean-François Collet
- WELBIO, Université catholique de Louvain, avenue Hippocrate 75, Brussels 1200, Belgium
- De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Brussels 1200, Belgium
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103
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Cheah HL, Raabe CA, Lee LP, Rozhdestvensky TS, Citartan M, Ahmed SA, Tang TH. Bacterial regulatory RNAs: complexity, function, and putative drug targeting. Crit Rev Biochem Mol Biol 2018; 53:335-355. [PMID: 29793351 DOI: 10.1080/10409238.2018.1473330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Over the past decade, RNA-deep sequencing has uncovered copious non-protein coding RNAs (npcRNAs) in bacteria. Many of them are key players in the regulation of gene expression, taking part in various regulatory circuits, such as metabolic responses to different environmental stresses, virulence, antibiotic resistance, and host-pathogen interactions. This has contributed to the high adaptability of bacteria to changing or even hostile environments. Their mechanisms include the regulation of transcriptional termination, modulation of translation, and alteration of messenger RNA (mRNA) stability, as well as protein sequestration. Here, the mechanisms of gene expression by regulatory bacterial npcRNAs are comprehensively reviewed and supplemented with well-characterized examples. This class of molecules and their mechanisms of action might be useful targets for the development of novel antibiotics.
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Affiliation(s)
- Hong-Leong Cheah
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Carsten A Raabe
- b Institute of Experimental Pathology, Centre for Molecular Biology of Inflammation , University of Münster , Münster , Germany.,c Brandenburg Medical School (MHB) , Neuruppin , Germany.,d Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation , University of Münster , Münster , Germany
| | - Li-Pin Lee
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Timofey S Rozhdestvensky
- e Medical Faculty, Transgenic Mouse and Genome Engineering Model Core Facility (TRAM) , University of Münster , Münster , Germany
| | - Marimuthu Citartan
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Siti Aminah Ahmed
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Thean-Hock Tang
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
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104
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Zhao X, Liu R, Tang H, Osei-Adjei G, Xu S, Zhang Y, Huang X. A 3' UTR-derived non-coding RNA RibS increases expression of cfa and promotes biofilm formation of Salmonella enterica serovar Typhi. Res Microbiol 2018; 169:279-288. [PMID: 29751065 DOI: 10.1016/j.resmic.2018.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 01/09/2023]
Abstract
Bacterial non-coding RNAs (ncRNAs) are widely studied and found to play important roles in regulating various cellular processes. Recently, many ncRNAs have been discovered to be transcribed or processed from 3' untranslated regions (3' UTRs). Here we reported a novel 3' UTR-derived ncRNA, RibS, which could influence biofilm formation of Salmonella enterica serovar Typhi (S. Typhi). RibS was confirmed to be a ∼700 nt processed product produced by RNase III-catalyzed cleavage from the 3' UTR of riboflavin synthase subunit alpha mRNA, RibE. Overexpression of RibS increased the expression of the cyclopropane fatty acid synthase gene, cfa, which was located at the antisense strand. Biofilm formation of S. Typhi was enhanced by overexpressing RibS both in the wild type strain and cfa deletion mutant. Deletion of cfa attenuated biofilm formation of S. Typhi, while complementation of cfa partly restored the phenotype. Moreover, overexpressing cfa enhanced the biofilm formation of S. Typhi. In summary, RibS has been identified as a novel ncRNA derived from the 3' UTR of RibE that promotes biofilm formation of S. Typhi, and it appears to do so, at least in part, by increasing the expression of cfa.
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Affiliation(s)
- Xin Zhao
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Rui Liu
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Hao Tang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - George Osei-Adjei
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Shungao Xu
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Xinxiang Huang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
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105
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Fitzgerald DM, Smith C, Lapierre P, Wade JT. The evolutionary impact of intragenic FliA promoters in proteobacteria. Mol Microbiol 2018; 108:361-378. [PMID: 29476659 PMCID: PMC5943157 DOI: 10.1111/mmi.13941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 12/12/2022]
Abstract
In Escherichia coli, one sigma factor recognizes the majority of promoters, and six 'alternative' sigma factors recognize specific subsets of promoters. The alternative sigma factor FliA (σ28 ) recognizes promoters upstream of many flagellar genes. We previously showed that most E. coli FliA binding sites are located inside genes. However, it was unclear whether these intragenic binding sites represent active promoters. Here, we construct and assay transcriptional promoter-lacZ fusions for all 52 putative FliA promoters previously identified by ChIP-seq. These experiments, coupled with integrative analysis of published genome-scale transcriptional datasets, strongly suggest that most intragenic FliA binding sites are active promoters that transcribe highly unstable RNAs. Additionally, we show that widespread intragenic FliA-dependent transcription may be a conserved phenomenon, but that specific promoters are not themselves conserved. We conclude that intragenic FliA-dependent promoters and the resulting RNAs are unlikely to have important regulatory functions. Nonetheless, one intragenic FliA promoter is broadly conserved and constrains evolution of the overlapping protein-coding gene. Thus, our data indicate that intragenic regulatory elements can influence bacterial protein evolution and suggest that the impact of intragenic regulatory sequences on genome evolution should be considered more broadly.
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Affiliation(s)
- Devon M. Fitzgerald
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
| | - Carol Smith
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Pascal Lapierre
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Joseph T. Wade
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
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106
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Mohanty BK, Kushner SR. Enzymes Involved in Posttranscriptional RNA Metabolism in Gram-Negative Bacteria. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0011-2017. [PMID: 29676246 PMCID: PMC5912700 DOI: 10.1128/microbiolspec.rwr-0011-2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 02/08/2023] Open
Abstract
Gene expression in Gram-negative bacteria is regulated at many levels, including transcription initiation, RNA processing, RNA/RNA interactions, mRNA decay, and translational controls involving enzymes that alter translational efficiency. In this review, we discuss the various enzymes that control transcription, translation, and RNA stability through RNA processing and degradation. RNA processing is essential to generate functional RNAs, while degradation helps control the steady-state level of each individual transcript. For example, all the pre-tRNAs are transcribed with extra nucleotides at both their 5' and 3' termini, which are subsequently processed to produce mature tRNAs that can be aminoacylated. Similarly, rRNAs that are transcribed as part of a 30S polycistronic transcript are matured to individual 16S, 23S, and 5S rRNAs. Decay of mRNAs plays a key role in gene regulation through controlling the steady-state level of each transcript, which is essential for maintaining appropriate protein levels. In addition, degradation of both translated and nontranslated RNAs recycles nucleotides to facilitate new RNA synthesis. To carry out all these reactions, Gram-negative bacteria employ a large number of endonucleases, exonucleases, RNA helicases, and poly(A) polymerase, as well as proteins that regulate the catalytic activity of particular RNases. Under certain stress conditions, an additional group of specialized endonucleases facilitate the cell's ability to adapt and survive. Many of the enzymes, such as RNase E, RNase III, polynucleotide phosphorylase, RNase R, and poly(A) polymerase I, participate in multiple RNA processing and decay pathways.
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Affiliation(s)
| | - Sidney R Kushner
- Department of Genetics
- Department of Microbiology, University of Georgia, Athens, GA 30602
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107
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Small RNA-mediated regulation in bacteria: A growing palette of diverse mechanisms. Gene 2018; 656:60-72. [PMID: 29501814 DOI: 10.1016/j.gene.2018.02.068] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/19/2018] [Accepted: 02/27/2018] [Indexed: 11/23/2022]
Abstract
Small RNAs (sRNAs) in bacteria have evolved with diverse mechanisms to balance their target gene expression in response to changes in the environment. Accumulating studies on bacterial regulatory processes firmly established that sRNAs modulate their target gene expression generally at the posttranscriptional level. Identification of large number of sRNAs by advanced technologies, like deep sequencing, tilling microarray, indicates the existence of a plethora of distinctive sRNA-mediated regulatory mechanisms in bacteria. Types of the novel mechanisms are increasing with the discovery of new sRNAs. Complementary base pairing between sRNAs and target RNAs assisted by RNA chaperones like Hfq and ProQ, in many occasions, to regulate the cognate gene expression is prevalent in sRNA mechanisms. sRNAs, in most studied cases, can directly base pair with target mRNA to remodel its expression. Base pairing can happen either in the untranslated regions or in the coding regions of mRNA to activate/repress its translation. sRNAs also act as target mimic to titrate away different regulatory RNAs from its target. Other mechanism includes the sequestration of regulatory proteins, especially transcription factors, by sRNAs. Numerous sRNAs, following analogous mechanism, are widespread in bacteria, and thus, has drawn immense attention for the development of RNA-based technologies. Nevertheless, typical sRNA mechanisms are also discovered to be confined in some bacteria. Analysis of the sRNA mechanisms unravels their existence in both the single step processes and the complex regulatory networks with a global effect on cell physiology. This review deals with the diverse array of mechanisms, which sRNAs follow to maintain bacterial lifestyle.
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108
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Vidovic S, Medihala P, Dynes JJ, Daida P, Vujanovic V, Hitchcock AP, Shetty D, Zhang H, Brown DR, Lawrence JR, Korber DR. Importance of the RpoE Regulon in Maintaining the Lipid Bilayer during Antimicrobial Treatment with the Polycationic Agent, Chlorhexidine. Proteomics 2018; 18. [PMID: 29280319 DOI: 10.1002/pmic.201700285] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 11/23/2017] [Indexed: 12/28/2022]
Abstract
The emergence of multidrug resistance in bacteria has reached alarming levels. To solve this growing problem, discovery of novel cellular targets or pathways important for antimicrobial resistance is urgently needed. In this study, we explored how the alternative sigma factor, RpoE, protects Escherichia coli O157 against the toxic effects of the polycationic antimicrobial agent, chlorhexidine (CHX). Susceptibility of this organism to CHX was found to directly correlate to the growth rate, with the faster replicating wild-type being more susceptible to CHX than its more slowly replicating ΔrpoE O157 mutant. Once the wild-type and rpoE mutant strains had undergone growth arrest (entered the stationary growth phase), their resistance to CHX became entirely dependent on the functionality of RpoE. The RpoE regulon plays a critical role in maintaining the integrity of the asymmetric lipid bilayer of E. coli, thereby preventing the intracellular accumulation of CHX. Finally, using a single-cell, high-resolution, synchrotron-based approach, we discovered a subpopulation of the rpoE mutant strain with no detectable intracellular CHX, a predominant characteristic of the wild-type CHX-resistant population. This finding reveals a role of phenotypic heterogeneity in antimicrobial resistance.
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Affiliation(s)
- Sinisa Vidovic
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Prabhakara Medihala
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Canada
| | - James J Dynes
- Canadian Light Source, Inc., University of Saskatchewan, Saskatoon, Canada
| | - Prasad Daida
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Vladimir Vujanovic
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Adam P Hitchcock
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Canada
| | - Deeksha Shetty
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Haixia Zhang
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Canada
| | - David R Brown
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | | | - Darren R Korber
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Canada
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109
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Dam S, Pagès JM, Masi M. Stress responses, outer membrane permeability control and antimicrobial resistance in Enterobacteriaceae. MICROBIOLOGY-SGM 2018; 164:260-267. [PMID: 29458656 DOI: 10.1099/mic.0.000613] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bacteria have evolved several strategies to survive a myriad of harmful conditions in the environment and in hosts. In Gram-negative bacteria, responses to nutrient limitation, oxidative or nitrosative stress, envelope stress, exposure to antimicrobials and other growth-limiting stresses have been linked to the development of antimicrobial resistance. This results from the activation of protective changes to cell physiology (decreased outer membrane permeability), resistance transporters (drug efflux pumps), resistant lifestyles (biofilms, persistence) and/or resistance mutations (target mutations, production of antibiotic modification/degradation enzymes). In targeting and interfering with essential physiological mechanisms, antimicrobials themselves are considered as stresses to which protective responses have also evolved. In this review, we focus on envelope stress responses that affect the expression of outer membrane porins and their impact on antimicrobial resistance. We also discuss evidences that indicate the role of antimicrobials as signaling molecules in activating envelope stress responses.
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Affiliation(s)
- Sushovan Dam
- UMR_MD-1, Aix-Marseille Univ. & IRBA, 27 Boulevard Jean Moulin, 13005 Marseille, France
| | - Jean-Marie Pagès
- UMR_MD-1, Aix-Marseille Univ. & IRBA, 27 Boulevard Jean Moulin, 13005 Marseille, France
| | - Muriel Masi
- UMR_MD-1, Aix-Marseille Univ. & IRBA, 27 Boulevard Jean Moulin, 13005 Marseille, France
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110
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Hör J, Gorski SA, Vogel J. Bacterial RNA Biology on a Genome Scale. Mol Cell 2018; 70:785-799. [PMID: 29358079 DOI: 10.1016/j.molcel.2017.12.023] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 12/11/2017] [Accepted: 12/22/2017] [Indexed: 12/16/2022]
Abstract
Bacteria are an exceedingly diverse group of organisms whose molecular exploration is experiencing a renaissance. While the classical view of bacterial gene expression was relatively simple, the emerging view is more complex, encompassing extensive post-transcriptional control involving riboswitches, RNA thermometers, and regulatory small RNAs (sRNAs) associated with the RNA-binding proteins CsrA, Hfq, and ProQ, as well as CRISPR/Cas systems that are programmed by RNAs. Moreover, increasing interest in members of the human microbiota and environmental microbial communities has highlighted the importance of understudied bacterial species with largely unknown transcriptome structures and RNA-based control mechanisms. Collectively, this creates a need for global RNA biology approaches that can rapidly and comprehensively analyze the RNA composition of a bacterium of interest. We review such approaches with a focus on RNA-seq as a versatile tool to investigate the different layers of gene expression in which RNA is made, processed, regulated, modified, translated, and turned over.
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Affiliation(s)
- Jens Hör
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Stanislaw A Gorski
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Jörg Vogel
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Helmholtz Institute for RNA-based Infection Research (HIRI), 97080 Würzburg, Germany.
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111
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112
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Asmar AT, Ferreira JL, Cohen EJ, Cho SH, Beeby M, Hughes KT, Collet JF. Communication across the bacterial cell envelope depends on the size of the periplasm. PLoS Biol 2017; 15:e2004303. [PMID: 29257832 PMCID: PMC5736177 DOI: 10.1371/journal.pbio.2004303] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/10/2017] [Indexed: 12/28/2022] Open
Abstract
The cell envelope of gram-negative bacteria, a structure comprising an outer (OM) and an inner (IM) membrane, is essential for life. The OM and the IM are separated by the periplasm, a compartment that contains the peptidoglycan. The OM is tethered to the peptidoglycan via the lipoprotein, Lpp. However, the importance of the envelope's multilayered architecture remains unknown. Here, when we removed physical coupling between the OM and the peptidoglycan, cells lost the ability to sense defects in envelope integrity. Further experiments revealed that the critical parameter for the transmission of stress signals from the envelope to the cytoplasm, where cellular behaviour is controlled, is the IM-to-OM distance. Augmenting this distance by increasing the length of the lipoprotein Lpp destroyed signalling, whereas simultaneously increasing the length of the stress-sensing lipoprotein RcsF restored signalling. Our results demonstrate the physiological importance of the size of the periplasm. They also reveal that strict control over the IM-to-OM distance is required for effective envelope surveillance and protection, suggesting that cellular architecture and the structure of transenvelope protein complexes have been evolutionarily co-optimised for correct function. Similar strategies are likely at play in cellular compartments surrounded by 2 concentric membranes, such as chloroplasts and mitochondria.
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Affiliation(s)
- Abir T. Asmar
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Josie L. Ferreira
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Eli J. Cohen
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Seung-Hyun Cho
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kelly T. Hughes
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Jean-François Collet
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
- WELBIO, Université catholique de Louvain, Brussels, Belgium
- * E-mail:
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113
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Potts AH, Vakulskas CA, Pannuri A, Yakhnin H, Babitzke P, Romeo T. Global role of the bacterial post-transcriptional regulator CsrA revealed by integrated transcriptomics. Nat Commun 2017; 8:1596. [PMID: 29150605 PMCID: PMC5694010 DOI: 10.1038/s41467-017-01613-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 10/03/2017] [Indexed: 12/12/2022] Open
Abstract
CsrA is a post-transcriptional regulatory protein that is widely distributed among bacteria. This protein influences bacterial lifestyle decisions by binding to the 5′ untranslated and/or early coding regions of mRNA targets, causing changes in translation initiation, RNA stability, and/or transcription elongation. Here, we assess the contribution of CsrA to gene expression in Escherichia coli on a global scale. UV crosslinking immunoprecipitation and sequencing (CLIP-seq) identify RNAs that interact directly with CsrA in vivo, while ribosome profiling and RNA-seq uncover the impact of CsrA on translation, RNA abundance, and RNA stability. This combination of approaches reveals unprecedented detail about the regulatory role of CsrA, including novel binding targets and physiological roles, such as in envelope function and iron homeostasis. Our findings highlight the integration of CsrA throughout the E. coli regulatory network, where it orchestrates vast effects on gene expression. The RNA-binding protein CsrA regulates the expression of hundreds of bacterial genes. Here, Potts et al. use several approaches to assess the contribution of CsrA to global gene expression in E. coli, revealing new binding targets and physiological roles such as in envelope function and iron homeostasis.
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Affiliation(s)
- Anastasia H Potts
- Department of Microbiology and Cell Science, University of Florida, Institute of Food and Agricultural Sciences, Gainesville, FL, 32611-0700, USA
| | - Christopher A Vakulskas
- Department of Microbiology and Cell Science, University of Florida, Institute of Food and Agricultural Sciences, Gainesville, FL, 32611-0700, USA.,Integrated DNA Technologies, Molecular Genetics Department, 1710 Commercial Park, Coralville, IA, 52241, USA
| | - Archana Pannuri
- Department of Microbiology and Cell Science, University of Florida, Institute of Food and Agricultural Sciences, Gainesville, FL, 32611-0700, USA
| | - Helen Yakhnin
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Tony Romeo
- Department of Microbiology and Cell Science, University of Florida, Institute of Food and Agricultural Sciences, Gainesville, FL, 32611-0700, USA.
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114
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Kavita K, de Mets F, Gottesman S. New aspects of RNA-based regulation by Hfq and its partner sRNAs. Curr Opin Microbiol 2017; 42:53-61. [PMID: 29125938 PMCID: PMC10367044 DOI: 10.1016/j.mib.2017.10.014] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 10/15/2017] [Accepted: 10/19/2017] [Indexed: 12/30/2022]
Abstract
Hfq, an RNA chaperone, promotes the pairing of small RNAs (sRNAs) to target mRNAs, mediating post-transcriptional regulation of mRNA stability and translation. This regulation contributes to bacterial adaptation during stress and pathogenesis. Recent advances in sequencing techniques demonstrate the presence of sRNAs encoded not only in intergenic regions but also from the 3' and 5' UTRs of mRNAs, expanding sRNA regulatory networks. Additional layers of regulation by Hfq and its associated RNAs continue to be found. Newly identified RNA sponges modulate the activity of some sRNAs. A subset of sRNAs are proving to be bifunctional, able to pair with targets and also encoding small ORFs or binding other RNA binding proteins, such as CsrA. In addition, there are accumulating examples of Hfq inhibiting mRNA translation in the absence of sRNAs.
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Affiliation(s)
- Kumari Kavita
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Francois de Mets
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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115
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Impact of bacterial sRNAs in stress responses. Biochem Soc Trans 2017; 45:1203-1212. [PMID: 29101308 PMCID: PMC5730939 DOI: 10.1042/bst20160363] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 12/11/2022]
Abstract
Bacterial life is harsh and involves numerous environmental and internal challenges that are perceived as stresses. Consequently, adequate responses to survive, cope with, and counteract stress conditions have evolved. In the last few decades, a class of small, non-coding RNAs (sRNAs) has been shown to be involved as key players in stress responses. This review will discuss — primarily from an enterobacterial perspective — selected stress response pathways that involve antisense-type sRNAs. These include themes of how bacteria deal with severe envelope stress, threats of DNA damage, problems with poisoning due to toxic sugar intermediates, issues of iron homeostasis, and nutrient limitation/starvation. The examples discussed highlight how stress relief can be achieved, and how sRNAs act mechanistically in regulatory circuits. For some cases, we will propose scenarios that may suggest why contributions from post-transcriptional control by sRNAs, rather than transcriptional control alone, appear to be a beneficial and universally selected feature.
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116
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Chao Y, Li L, Girodat D, Förstner KU, Said N, Corcoran C, Śmiga M, Papenfort K, Reinhardt R, Wieden HJ, Luisi BF, Vogel J. In Vivo Cleavage Map Illuminates the Central Role of RNase E in Coding and Non-coding RNA Pathways. Mol Cell 2017; 65:39-51. [PMID: 28061332 PMCID: PMC5222698 DOI: 10.1016/j.molcel.2016.11.002] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/26/2016] [Accepted: 10/31/2016] [Indexed: 01/21/2023]
Abstract
Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 3' fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators.
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Affiliation(s)
- Yanjie Chao
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Lei Li
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Dylan Girodat
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Konrad U Förstner
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Nelly Said
- Laboratory of Structural Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Colin Corcoran
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Michał Śmiga
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Kai Papenfort
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Department of Biology I, Microbiology, Ludwig-Maximilians-Universität Munich, 82152 Martinsried, Germany
| | - Richard Reinhardt
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Jörg Vogel
- Institute of Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Helmholtz Institute for RNA-based Infection Research (HIRI), 97080 Würzburg, Germany.
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117
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Programmed Ribosomal Frameshifting Generates a Copper Transporter and a Copper Chaperone from the Same Gene. Mol Cell 2017; 65:207-219. [PMID: 28107647 DOI: 10.1016/j.molcel.2016.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 11/23/2016] [Accepted: 12/13/2016] [Indexed: 12/18/2022]
Abstract
Metal efflux pumps maintain ion homeostasis in the cell. The functions of the transporters are often supported by chaperone proteins, which scavenge the metal ions from the cytoplasm. Although the copper ion transporter CopA has been known in Escherichia coli, no gene for its chaperone had been identified. We show that the CopA chaperone is expressed in E. coli from the same gene that encodes the transporter. Some ribosomes translating copA undergo programmed frameshifting, terminate translation in the -1 frame, and generate the 70 aa-long polypeptide CopA(Z), which helps cells survive toxic copper concentrations. The high efficiency of frameshifting is achieved by the combined stimulatory action of a "slippery" sequence, an mRNA pseudoknot, and the CopA nascent chain. Similar mRNA elements are not only found in the copA genes of other bacteria but are also present in ATP7B, the human homolog of copA, and direct ribosomal frameshifting in vivo.
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118
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Heidrich N, Bauriedl S, Barquist L, Li L, Schoen C, Vogel J. The primary transcriptome of Neisseria meningitidis and its interaction with the RNA chaperone Hfq. Nucleic Acids Res 2017; 45:6147-6167. [PMID: 28334889 PMCID: PMC5449619 DOI: 10.1093/nar/gkx168] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/02/2017] [Indexed: 12/15/2022] Open
Abstract
Neisseria meningitidis is a human commensal that can also cause life-threatening meningitis and septicemia. Despite growing evidence for RNA-based regulation in meningococci, their transcriptome structure and output of regulatory small RNAs (sRNAs) are incompletely understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptome of N. meningitidis strain 8013. Annotation of 1625 transcriptional start sites defines transcription units for most protein-coding genes but also reveals a paucity of classical σ70-type promoters, suggesting the existence of activators that compensate for the lack of −35 consensus sequences in N. meningitidis. The transcriptome maps also reveal 65 candidate sRNAs, a third of which were validated by northern blot analysis. Immunoprecipitation with the RNA chaperone Hfq drafts an unexpectedly large post-transcriptional regulatory network in this organism, comprising 23 sRNAs and hundreds of potential mRNA targets. Based on this data, using a newly developed gfp reporter system we validate an Hfq-dependent mRNA repression of the putative colonization factor PrpB by the two trans-acting sRNAs RcoF1/2. Our genome-wide RNA compendium will allow for a better understanding of meningococcal transcriptome organization and riboregulation with implications for colonization of the human nasopharynx.
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Affiliation(s)
- Nadja Heidrich
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
| | - Saskia Bauriedl
- Institute for Hygiene and Microbiology (IHM), University of Würzburg, D-97080 Würzburg, Germany
| | - Lars Barquist
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
| | - Lei Li
- Division of Biostatistics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christoph Schoen
- Institute for Hygiene and Microbiology (IHM), University of Würzburg, D-97080 Würzburg, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany.,Helmholtz Institute for RNA-based Infection Research (HIRI), D-97080 Würzburg, Germany
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119
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Ellis MJ, Trussler RS, Charles O, Haniford DB. A transposon-derived small RNA regulates gene expression in Salmonella Typhimurium. Nucleic Acids Res 2017; 45:5470-5486. [PMID: 28335027 PMCID: PMC5435999 DOI: 10.1093/nar/gkx094] [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: 09/21/2016] [Accepted: 02/06/2017] [Indexed: 12/30/2022] Open
Abstract
Bacterial sRNAs play an important role in regulating many cellular processes including metabolism, outer membrane homeostasis and virulence. Although sRNAs were initially found in intergenic regions, there is emerging evidence that protein coding regions of the genome are a rich reservoir of sRNAs. Here we report that the 5΄UTR of IS200 transposase mRNA (tnpA) is processed to produce regulatory RNAs that affect expression of over 70 genes in Salmonella Typhimurium. We provide evidence that the tnpA derived sRNA base-pairs with invF mRNA to repress expression. As InvF is a transcriptional activator of SPI-1 encoded and other effector proteins, tnpA indirectly represses these genes. We show that deletion of IS200 elements in S. Typhimurium increases invasion in vitro and reduces growth rate, while over-expression of tnpA suppresses invasion. Our work indicates that tnpA acts as an sRNA ‘sponge’ that sets a threshold for activation of Salmonella pathogenicity island (SPI)-1 effector proteins and identifies a new class of ‘passenger gene’ for bacterial transposons, providing the first example of a bacterial transposon producing a regulatory RNA that controls host gene expression.
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Affiliation(s)
- Michael J Ellis
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ryan S Trussler
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Onella Charles
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - David B Haniford
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
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120
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Melamed S, Peer A, Faigenbaum-Romm R, Gatt YE, Reiss N, Bar A, Altuvia Y, Argaman L, Margalit H. Global Mapping of Small RNA-Target Interactions in Bacteria. Mol Cell 2017; 63:884-97. [PMID: 27588604 PMCID: PMC5145812 DOI: 10.1016/j.molcel.2016.07.026] [Citation(s) in RCA: 255] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 04/25/2016] [Accepted: 07/27/2016] [Indexed: 02/07/2023]
Abstract
Small RNAs (sRNAs) associated with the RNA chaperon protein Hfq are key posttranscriptional regulators of gene expression in bacteria. Deciphering the sRNA-target interactome is an essential step toward understanding the roles of sRNAs in the cellular networks. We developed a broadly applicable methodology termed RIL-seq (RNA interaction by ligation and sequencing), which integrates experimental and computational tools for in vivo transcriptome-wide identification of interactions involving Hfq-associated sRNAs. By applying this methodology to Escherichia coli we discovered an extensive network of interactions involving RNA pairs showing sequence complementarity. We expand the ensemble of targets for known sRNAs, uncover additional Hfq-bound sRNAs encoded in various genomic regions along with their trans encoded targets, and provide insights into binding and possible cycling of RNAs on Hfq. Comparison of the sRNA interactome under various conditions has revealed changes in the sRNA repertoire as well as substantial re-wiring of the network between conditions. A widely applicable method for in vivo global mapping of small RNA interactome Substantial re-wiring of the network upon changes in cellular conditions Regulatory circuits involving two regulators derived from the same transcript sRNAs acting in trans are encoded within almost every possible genomic element
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Affiliation(s)
- Sahar Melamed
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Asaf Peer
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Raya Faigenbaum-Romm
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Yair E Gatt
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Niv Reiss
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Amir Bar
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Yael Altuvia
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Liron Argaman
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Hanah Margalit
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
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121
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Xia H, Yang X, Tang Q, Ye J, Wu H, Zhang H. EsrE-A yigP Locus-Encoded Transcript-Is a 3' UTR sRNA Involved in the Respiratory Chain of E. coli. Front Microbiol 2017; 8:1658. [PMID: 28900423 PMCID: PMC5581919 DOI: 10.3389/fmicb.2017.01658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 08/15/2017] [Indexed: 01/20/2023] Open
Abstract
The yigP locus is widely conserved among γ-proteobacteria. Mutation of the yigP locus impacts aerobic growth of Gram-negative bacteria. However, the underlying mechanism of how the yigP locus influences aerobic growth remains largely unknown. Here, we demonstrated that the yigP locus in Escherichia coli encodes two transcripts; the mRNA of ubiquinone biosynthesis protein, UbiJ, and the 3′ untranslated region small regulatory RNA (sRNA), EsrE. EsrE is an independent transcript that is transcribed using an internal promoter of the yigP locus. Surprisingly, we found that both the EsrE sRNA and UbiJ protein were required for Q8 biosynthesis, and were sufficient to rescue the growth defect ascribed to deletion of the yigP locus. Moreover, our data showed that EsrE targeted multiple mRNAs involved in several cellular processes including murein biosynthesis and the tricarboxylic acid cycle. Among these targets, sdhD mRNA that encodes one subunit of succinate dehydrogenase (SDH), was significantly activated. Our findings provided an insight into the important function of EsrE in bacterial adaptation to various environments, as well as coordinating different aspects of bacterial physiology.
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Affiliation(s)
- Hui Xia
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China
| | - Xichen Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China
| | - Qiongwei Tang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China
| | - Jiang Ye
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China
| | - Haizhen Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China.,Department of Applied Biology, East China University of Science and TechnologyShanghai, China
| | - Huizhan Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and TechnologyShanghai, China.,Department of Applied Biology, East China University of Science and TechnologyShanghai, China
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122
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Guilbaud M, Bruzaud J, Bouffartigues E, Orange N, Guillot A, Aubert-Frambourg A, Monnet V, Herry JM, Chevalier S, Bellon-Fontaine MN. Proteomic Response of Pseudomonas aeruginosa PAO1 Adhering to Solid Surfaces. Front Microbiol 2017; 8:1465. [PMID: 28824592 PMCID: PMC5541441 DOI: 10.3389/fmicb.2017.01465] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is a pathogenic micro-organism responsible for many hospital-acquired infections. It is able to adhere to solid surfaces and develop an immobilized community or so-called biofilm. Many studies have been focusing on the use of specific materials to prevent the formation of these biofilms, but the reactivity of the bacteria in contact to surfaces remains unknown. The aim of this study was to evaluate the impact of the abiotic surface on the physiology of adherent bacteria. Three different materials, stainless steel (SS), glass (G), and polystyrene (PS) that were relevant to industrial or medical environments were characterized at the physicochemical level in terms of their hydrophobicity and roughness. We showed that SS was moderately hydrophilic and rough, potentially containing crevices, G was hydrophilic and smooth while PS was hydrophobic and smooth. We further showed that P. aeruginosa cells were more likely able to adhere to SS and G rather than PS surfaces under our experimental conditions. The physiological response of P. aeruginosa when adhering to each of these materials was then evaluated by global proteomic analysis. The abundance of 70 proteins was shown to differ between the materials suggesting that their abundance was modified as a function of the material to which bacteria adhered. Our data lead to enabling the identification of abundance patterns that appeared to be specific to a given surface. Taken together, our data showed that P. aeruginosa is capable of sensing and responding to a surface probably via specific programmes to adapt its physiological response accordingly.
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Affiliation(s)
- Morgan Guilbaud
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Jérôme Bruzaud
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Emeline Bouffartigues
- Laboratoire de Microbiologie, Signaux et Microenvironnement, Normandie Université, Université de Rouen-NormandieRouen, France
| | - Nicole Orange
- Laboratoire de Microbiologie, Signaux et Microenvironnement, Normandie Université, Université de Rouen-NormandieRouen, France
| | - Alain Guillot
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Anne Aubert-Frambourg
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Véronique Monnet
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Jean-Marie Herry
- Micalis Institute, INRA, AgroParisTech, Université Paris-SaclayJouy-en-Josas, France
| | - Sylvie Chevalier
- Laboratoire de Microbiologie, Signaux et Microenvironnement, Normandie Université, Université de Rouen-NormandieRouen, France
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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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124
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Small and Smaller-sRNAs and MicroRNAs in the Regulation of Toxin Gene Expression in Prokaryotic Cells: A Mini-Review. Toxins (Basel) 2017; 9:toxins9060181. [PMID: 28556797 PMCID: PMC5488031 DOI: 10.3390/toxins9060181] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/09/2017] [Accepted: 05/26/2017] [Indexed: 12/14/2022] Open
Abstract
Non-coding small RNAs (sRNAs) have been identified in the wide range of bacteria (also pathogenic species) and found to play an important role in the regulation of many processes, including toxin gene expression. The best characterized prokaryotic sRNAs regulate gene expression by base pairing with mRNA targets and fall into two broad classes: cis-encoded sRNAs (also called antisense RNA) and trans-acting sRNAs. Molecules from the second class are frequently considered as the most related to eukaryotic microRNAs. Interestingly, typical microRNA-size RNA molecules have also been reported in prokaryotic cells, although they have received little attention up to now. In this work we have collected information about all three types of small prokaryotic RNAs in the context of the regulation of toxin gene expression.
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125
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Appropriate Regulation of the σ E-Dependent Envelope Stress Response Is Necessary To Maintain Cell Envelope Integrity and Stationary-Phase Survival in Escherichia coli. J Bacteriol 2017; 199:JB.00089-17. [PMID: 28373273 DOI: 10.1128/jb.00089-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/27/2017] [Indexed: 12/18/2022] Open
Abstract
The alternative sigma factor σE is a key component of the Escherichia coli response to cell envelope stress and is required for viability even in the absence of stress. The activity of σE increases during entry into stationary phase, suggesting an important role for σE when nutrients are limiting. Elevated σE activity has been proposed to activate a pathway leading to the lysis of nonculturable cells that accumulate during early stationary phase. To better understand σE-directed cell lysis and the role of σE in stationary phase, we investigated the effects of elevated σE activity in cultures grown for 10 days. We demonstrate that high σE activity is lethal for all cells in stationary phase, not only those that are nonculturable. Spontaneous mutants with reduced σE activity, due primarily to point mutations in the region of σE that binds the -35 promoter motif, arise and take over cultures within 5 to 6 days after entry into stationary phase. High σE activity leads to large reductions in the levels of outer membrane porins and increased membrane permeability, indicating membrane defects. These defects can be counteracted and stationary-phase lethality delayed significantly by stabilizing membranes with Mg2+ and buffering the growth medium or by deleting the σE-dependent small RNAs (sRNAs) MicA, RybB, and MicL, which inhibit the expression of porins and Lpp. Expression of these sRNAs also reverses the loss of viability following depletion of σE activity. Our results demonstrate that appropriate regulation of σE activity, ensuring that it is neither too high nor too low, is critical for envelope integrity and cell viability.IMPORTANCE The Gram-negative cell envelope and cytoplasm differ significantly, and separate responses have evolved to combat stress in each compartment. An array of cell envelope stress responses exist, each of which is focused on different parts of the envelope. The σE response is conserved in many enterobacteria and is tuned to monitor pathways for the maturation and delivery of outer membrane porins, lipoproteins, and lipopolysaccharide to the outer membrane. The activity of σE is tightly regulated to match the production of σE regulon members to the needs of the cell. In E. coli, loss of σE results in lethality. Here we demonstrate that excessive σE activity is also lethal and results in decreased membrane integrity, the very phenotype the system is designed to prevent.
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126
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Identification of the Lyso-Form N-Acyl Intramolecular Transferase in Low-GC Firmicutes. J Bacteriol 2017; 199:JB.00099-17. [PMID: 28320885 DOI: 10.1128/jb.00099-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/14/2017] [Indexed: 12/25/2022] Open
Abstract
Bacterial lipoproteins are embedded in the cell membrane of both Gram-positive and Gram-negative bacteria, where they serve numerous functions central to cell envelope physiology. Lipoproteins are tethered to the membrane by an N-acyl-S-(mono/di)-acyl-glyceryl-cysteine anchor that is variously acylated depending on the genus. In several low-GC, Gram-positive firmicutes, a monoacyl-glyceryl-cysteine with an N-terminal fatty acid (known as the lyso form) has been reported, though how it is formed is unknown. Here, through an intergenic complementation rescue assay in Escherichia coli, we report the identification of a common orthologous transmembrane protein in both Enterococcus faecalis and Bacillus cereus that is capable of forming lyso-form lipoproteins. When deleted from the native host, lipoproteins remain diacylated with a free N terminus, as maturation to the N-acylated lyso form is abolished. Evidence is presented suggesting that the previously unknown gene product functions through a novel intramolecular transacylation mechanism, transferring a fatty acid from the diacylglycerol moiety to the α-amino group of the lipidated cysteine. As such, the discovered gene has been named lipoprotein intramolecular transacylase (lit), to differentiate it from the gene for the intermolecular N-acyltransferase (lnt) involved in triacyl lipoprotein biosynthesis in Gram-negative organisms.IMPORTANCE This study identifies a new enzyme, conserved among low-GC, Gram-positive bacteria, that is involved in bacterial lipoprotein biosynthesis and synthesizes lyso-form lipoproteins. Its discovery is an essential first step in determining the physiological role of N-terminal lipoprotein acylation in Gram-positive bacteria and how these modifications impact bacterial cell envelope function.
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127
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Dersch P, Khan MA, Mühlen S, Görke B. Roles of Regulatory RNAs for Antibiotic Resistance in Bacteria and Their Potential Value as Novel Drug Targets. Front Microbiol 2017; 8:803. [PMID: 28529506 PMCID: PMC5418344 DOI: 10.3389/fmicb.2017.00803] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/19/2017] [Indexed: 01/23/2023] Open
Abstract
The emergence of antibiotic resistance mechanisms among bacterial pathogens increases the demand for novel treatment strategies. Lately, the contribution of non-coding RNAs to antibiotic resistance and their potential value as drug targets became evident. RNA attenuator elements in mRNA leader regions couple expression of resistance genes to the presence of the cognate antibiotic. Trans-encoded small RNAs (sRNAs) modulate antibiotic tolerance by base-pairing with mRNAs encoding functions important for resistance such as metabolic enzymes, drug efflux pumps, or transport proteins. Bacteria respond with extensive changes of their sRNA repertoire to antibiotics. Each antibiotic generates a unique sRNA profile possibly causing downstream effects that may help to overcome the antibiotic challenge. In consequence, regulatory RNAs including sRNAs and their protein interaction partners such as Hfq may prove useful as targets for antimicrobial chemotherapy. Indeed, several compounds have been developed that kill bacteria by mimicking ligands for riboswitches controlling essential genes, demonstrating that regulatory RNA elements are druggable targets. Drugs acting on sRNAs are considered for combined therapies to treat infections. In this review, we address how regulatory RNAs respond to and establish resistance to antibiotics in bacteria. Approaches to target RNAs involved in intrinsic antibiotic resistance or virulence for chemotherapy will be discussed.
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Affiliation(s)
- Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Muna A Khan
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
| | - Sabrina Mühlen
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
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128
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Small regulatory bacterial RNAs regulating the envelope stress response. Biochem Soc Trans 2017; 45:417-425. [PMID: 28408482 PMCID: PMC5736990 DOI: 10.1042/bst20160367] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 02/05/2017] [Accepted: 02/07/2017] [Indexed: 12/21/2022]
Abstract
Most bacteria encode a large repertoire of RNA-based regulatory mechanisms. Recent discoveries have revealed that the expression of many genes is controlled by a plethora of base-pairing noncoding small regulatory RNAs (sRNAs), regulatory RNA-binding proteins and RNA-degrading enzymes. Some of these RNA-based regulated processes respond to stress conditions and are involved in the maintenance of cellular homeostasis. They achieve it by either direct posttranscriptional repression of several mRNAs, including blocking access to ribosome and/or directing them to RNA degradation when the synthesis of their cognate proteins is unwanted, or by enhanced translation of some key stress-regulated transcriptional factors. Noncoding RNAs that regulate the gene expression by binding to regulatory proteins/transcriptional factors often act negatively by sequestration, preventing target recognition. Expression of many sRNAs is positively regulated by stress-responsive sigma factors like RpoE and RpoS, and two-component systems like PhoP/Q, Cpx and Rcs. Some of these regulatory RNAs act via a feedback mechanism on their own regulators, which is best reflected by recent discoveries, concerning the regulation of cell membrane composition by sRNAs in Escherichia coli and Salmonella, which are highlighted here.
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129
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Prasse D, Förstner KU, Jäger D, Backofen R, Schmitz RA. sRNA 154 a newly identified regulator of nitrogen fixation in Methanosarcina mazei strain Gö1. RNA Biol 2017; 14:1544-1558. [PMID: 28296572 DOI: 10.1080/15476286.2017.1306170] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Trans-encoded sRNA154 is exclusively expressed under nitrogen (N)-deficiency in Methanosarcina mazei strain Gö1. The sRNA154 deletion strain showed a significant decrease in growth under N-limitation, pointing toward a regulatory role of sRNA154 in N-metabolism. Aiming to elucidate its regulatory function we characterized sRNA154 by means of biochemical and genetic approaches. 24 homologs of sRNA154 were identified in recently reported draft genomes of Methanosarcina strains, demonstrating high conservation in sequence and predicted secondary structure with two highly conserved single stranded loops. Transcriptome studies of sRNA154 deletion mutants by an RNA-seq approach uncovered nifH- and nrpA-mRNA, encoding the α-subunit of nitrogenase and the transcriptional activator of the nitrogen fixation (nif)-operon, as potential targets besides other components of the N-metabolism. Furthermore, results obtained from stability, complementation and western blot analysis, as well as in silico target predictions combined with electrophoretic mobility shift-assays, argue for a stabilizing effect of sRNA154 on the polycistronic nif-mRNA and nrpA-mRNA by binding with both loops. Further identified N-related targets were studied, which demonstrates that translation initiation of glnA2-mRNA, encoding glutamine synthetase2, appears to be affected by sRNA154 masking the ribosome binding site, whereas glnA1-mRNA appears to be stabilized by sRNA154. Overall, we propose that sRNA154 has a crucial regulatory role in N-metabolism in M. mazei by stabilizing the polycistronic mRNA encoding nitrogenase and glnA1-mRNA, as well as allowing a feed forward regulation of nif-gene expression by stabilizing nrpA-mRNA. Consequently, sRNA154 represents the first archaeal sRNA, for which a positive posttranscriptional regulation is demonstrated as well as inhibition of translation initiation.
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Affiliation(s)
- Daniela Prasse
- a Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel , Am Botanischen Garten 1-9, Kiel , Germany
| | - Konrad U Förstner
- b Zentrum für Infektionsforschung , Universität Würzburg , Josef Schneider-Str. 2/ Bau D15, Würzburg
| | - Dominik Jäger
- a Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel , Am Botanischen Garten 1-9, Kiel , Germany
| | - Rolf Backofen
- c Institut für Informatik, Albert-Ludwigs-Universität zu Freiburg , Georges-Koehler-Allee, Freiburg , Germany
| | - Ruth A Schmitz
- a Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel , Am Botanischen Garten 1-9, Kiel , Germany
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130
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García-Bayona L, Guo MS, Laub MT. Contact-dependent killing by Caulobacter crescentus via cell surface-associated, glycine zipper proteins. eLife 2017; 6:e24869. [PMID: 28323618 PMCID: PMC5380434 DOI: 10.7554/elife.24869] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/20/2017] [Indexed: 12/18/2022] Open
Abstract
Most bacteria are in fierce competition with other species for limited nutrients. Some bacteria can kill nearby cells by secreting bacteriocins, a diverse group of proteinaceous antimicrobials. However, bacteriocins are typically freely diffusible, and so of little value to planktonic cells in aqueous environments. Here, we identify an atypical two-protein bacteriocin in the α-proteobacterium Caulobacter crescentus that is retained on the surface of producer cells where it mediates cell contact-dependent killing. The bacteriocin-like proteins CdzC and CdzD harbor glycine-zipper motifs, often found in amyloids, and CdzC forms large, insoluble aggregates on the surface of producer cells. These aggregates can drive contact-dependent killing of other organisms, or Caulobacter cells not producing the CdzI immunity protein. The Cdz system uses a type I secretion system and is unrelated to previously described contact-dependent inhibition systems. However, Cdz-like systems are found in many bacteria, suggesting that this form of contact-dependent inhibition is common.
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Affiliation(s)
- Leonor García-Bayona
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
- Graduate Program in Microbiology, Massachusetts Institute of Technology, Cambridge, United States
| | - Monica S Guo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
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131
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New RNA-seq approaches for the study of bacterial pathogens. Curr Opin Microbiol 2017; 35:78-87. [DOI: 10.1016/j.mib.2017.01.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 12/17/2022]
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132
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Colameco S, Elliot MA. Non-coding RNAs as antibiotic targets. Biochem Pharmacol 2016; 133:29-42. [PMID: 28012959 DOI: 10.1016/j.bcp.2016.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/12/2016] [Indexed: 02/07/2023]
Abstract
Antibiotics inhibit a wide range of essential processes in the bacterial cell, including replication, transcription, translation and cell wall synthesis. In many instances, these antibiotics exert their effects through association with non-coding RNAs. This review highlights many classical antibiotic targets (e.g. rRNAs and the ribosome), explores a number of emerging targets (e.g. tRNAs, RNase P, riboswitches and small RNAs), and discusses the future directions and challenges associated with non-coding RNAs as antibiotic targets.
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Affiliation(s)
- Savannah Colameco
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Marie A Elliot
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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133
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da Silva RAG, Churchward CP, Karlyshev AV, Eleftheriadou O, Snabaitis AK, Longman MR, Ryan A, Griffin R. The role of apolipoprotein N-acyl transferase, Lnt, in the lipidation of factor H binding protein of Neisseria meningitidis strain MC58 and its potential as a drug target. Br J Pharmacol 2016; 174:2247-2260. [PMID: 27784136 DOI: 10.1111/bph.13660] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/06/2016] [Accepted: 10/13/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The level of cell surface expression of the meningococcal vaccine antigen, Factor H binding protein (FHbp) varies between and within strains and this limits the breadth of strains that can be targeted by FHbp-based vaccines. The molecular pathway controlling expression of FHbp at the cell surface, including its lipidation, sorting to the outer membrane and export, and the potential regulation of this pathway have not been investigated until now. This knowledge will aid our evaluation of FHbp vaccines. EXPERIMENTAL APPROACH A meningococcal transposon library was screened by whole cell immuno-dot blotting using an anti-FHbp antibody to identify a mutant with reduced binding and the disrupted gene was determined. KEY RESULTS In a mutant with markedly reduced binding, the transposon was located in the lnt gene which encodes apolipoprotein N-acyl transferase, Lnt, responsible for the addition of the third fatty acid to apolipoproteins prior to their sorting to the outer membrane. We provide data indicating that in the Lnt mutant, FHbp is diacylated and its expression within the cell is reduced 10 fold, partly due to inhibition of transcription. Furthermore the Lnt mutant showed 64 fold and 16 fold increase in susceptibility to rifampicin and ciprofloxacin respectively. CONCLUSION AND IMPLICATIONS We speculate that the inefficient sorting of diacylated FHbp in the meningococcus results in its accumulation in the periplasm inducing an envelope stress response to down-regulate its expression. We propose Lnt as a potential novel drug target for combination therapy with antibiotics. LINKED ARTICLES This article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.14/issuetoc.
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Affiliation(s)
- R A G da Silva
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - C P Churchward
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A V Karlyshev
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - O Eleftheriadou
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A K Snabaitis
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - M R Longman
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A Ryan
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - R Griffin
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
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134
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Narita SI, Tokuda H. Bacterial lipoproteins; biogenesis, sorting and quality control. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1414-1423. [PMID: 27871940 DOI: 10.1016/j.bbalip.2016.11.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022]
Abstract
Bacterial lipoproteins are a subset of membrane proteins localized on either leaflet of the lipid bilayer. These proteins are anchored to membranes through their N-terminal lipid moiety attached to a conserved Cys. Since the protein moiety of most lipoproteins is hydrophilic, they are expected to play various roles in a hydrophilic environment outside the cytoplasmic membrane. Gram-negative bacteria such as Escherichia coli possess an outer membrane, to which most lipoproteins are sorted. The Lol pathway plays a central role in the sorting of lipoproteins to the outer membrane after lipoprotein precursors are processed to mature forms in the cytoplasmic membrane. Most lipoproteins are anchored to the inner leaflet of the outer membrane with their protein moiety in the periplasm. However, recent studies indicated that some lipoproteins further undergo topology change in the outer membrane, and play critical roles in the biogenesis and quality control of the outer membrane. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Affiliation(s)
| | - Hajime Tokuda
- University of Morioka, Takizawa, Iwate 020-0694, Japan.
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135
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The Small RNA GcvB Promotes Mutagenic Break Repair by Opposing the Membrane Stress Response. J Bacteriol 2016; 198:3296-3308. [PMID: 27698081 PMCID: PMC5116933 DOI: 10.1128/jb.00555-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/22/2016] [Indexed: 12/19/2022] Open
Abstract
Microbes and human cells possess mechanisms of mutagenesis activated by stress responses. Stress-inducible mutagenesis mechanisms may provide important models for mutagenesis that drives host-pathogen interactions, antibiotic resistance, and possibly much of evolution generally. In Escherichia coli, repair of DNA double-strand breaks is switched to a mutagenic mode, using error-prone DNA polymerases, via the SOS DNA damage and general (σS) stress responses. We investigated small RNA (sRNA) clients of Hfq, an RNA chaperone that promotes mutagenic break repair (MBR), and found that GcvB promotes MBR by allowing a robust σS response, achieved via opposing the membrane stress (σE) response. Cells that lack gcvB were MBR deficient and displayed reduced σS-dependent transcription but not reduced σS protein levels. The defects in MBR and σS-dependent transcription in ΔgcvB cells were alleviated by artificially increasing σS levels, implying that GcvB promotes mutagenesis by allowing a normal σS response. ΔgcvB cells were highly induced for the σE response, and blocking σE response induction restored both mutagenesis and σS-promoted transcription. We suggest that GcvB may promote the σS response and mutagenesis indirectly, by promoting membrane integrity, which keeps σE levels lower. At high levels, σE might outcompete σS for binding RNA polymerase and so reduce the σS response and mutagenesis. The data show the delicate balance of stress response modulation of mutagenesis. IMPORTANCE Mutagenesis mechanisms upregulated by stress responses promote de novo antibiotic resistance and cross-resistance in bacteria, antifungal drug resistance in yeasts, and genome instability in cancer cells under hypoxic stress. This paper describes the role of a small RNA (sRNA) in promoting a stress-inducible-mutagenesis mechanism, mutagenic DNA break repair in Escherichia coli The roles of many sRNAs in E. coli remain unknown. This study shows that ΔgcvB cells, which lack the GcvB sRNA, display a hyperactivated membrane stress response and reduced general stress response, possibly because of sigma factor competition for RNA polymerase. This results in a mutagenic break repair defect. The data illuminate a function of GcvB sRNA in opposing the membrane stress response, and thus indirectly upregulating mutagenesis.
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136
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Waters SA, McAteer SP, Kudla G, Pang I, Deshpande NP, Amos TG, Leong KW, Wilkins MR, Strugnell R, Gally DL, Tollervey D, Tree JJ. Small RNA interactome of pathogenic E. coli revealed through crosslinking of RNase E. EMBO J 2016; 36:374-387. [PMID: 27836995 PMCID: PMC5286369 DOI: 10.15252/embj.201694639] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 10/06/2016] [Accepted: 10/11/2016] [Indexed: 02/04/2023] Open
Abstract
RNA sequencing studies have identified hundreds of non‐coding RNAs in bacteria, including regulatory small RNA (sRNA). However, our understanding of sRNA function has lagged behind their identification due to a lack of tools for the high‐throughput analysis of RNA–RNA interactions in bacteria. Here we demonstrate that in vivo sRNA–mRNA duplexes can be recovered using UV‐crosslinking, ligation and sequencing of hybrids (CLASH). Many sRNAs recruit the endoribonuclease, RNase E, to facilitate processing of mRNAs. We were able to recover base‐paired sRNA–mRNA duplexes in association with RNase E, allowing proximity‐dependent ligation and sequencing of cognate sRNA–mRNA pairs as chimeric reads. We verified that this approach captures bona fide sRNA–mRNA interactions. Clustering analyses identified novel sRNA seed regions and sets of potentially co‐regulated target mRNAs. We identified multiple mRNA targets for the pathotype‐specific sRNA Esr41, which was shown to regulate colicin sensitivity and iron transport in E. coli. Numerous sRNA interactions were also identified with non‐coding RNAs, including sRNAs and tRNAs, demonstrating the high complexity of the sRNA interactome.
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Affiliation(s)
- Shafagh A Waters
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sean P McAteer
- The Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Grzegorz Kudla
- MRC Human Genetic Unit, University of Edinburgh, Edinburgh, UK
| | - Ignatius Pang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Systems Biology Initiative, University of New South Wales, Sydney, NSW, Australia
| | - Nandan P Deshpande
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Systems Biology Initiative, University of New South Wales, Sydney, NSW, Australia
| | - Timothy G Amos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Kai Wen Leong
- Peter Doherty Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Systems Biology Initiative, University of New South Wales, Sydney, NSW, Australia
| | - Richard Strugnell
- Peter Doherty Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - David L Gally
- The Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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137
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Grabowicz M, Silhavy TJ. Envelope Stress Responses: An Interconnected Safety Net. Trends Biochem Sci 2016; 42:232-242. [PMID: 27839654 DOI: 10.1016/j.tibs.2016.10.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 12/14/2022]
Abstract
The Escherichia coli cell envelope is a protective barrier at the frontline of interaction with the environment. Fidelity of envelope biogenesis must be monitored to establish and maintain a contiguous barrier. Indeed, the envelope must also be repaired and modified in response to environmental assaults. Envelope stress responses (ESRs) sense envelope damage or defects and alter the transcriptome to mitigate stress. Here, we review recent insights into the stress-sensing mechanisms of the σE and Cpx systems and the interaction of these ESRs. Small RNAs (sRNAs) are increasingly prominent regulators of the transcriptional response to stress. These fast-acting regulators also provide avenues for inter-ESR regulation that could be important when cells face multiple contemporaneous stresses, as is the case during infection.
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Affiliation(s)
- Marcin Grabowicz
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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138
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Mechanistic study of base-pairing small regulatory RNAs in bacteria. Methods 2016; 117:67-76. [PMID: 27693881 DOI: 10.1016/j.ymeth.2016.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 09/22/2016] [Indexed: 11/24/2022] Open
Abstract
In all three kingdoms of life, RNA is not only involved in the expression of genetic information, but also carries out extremely diverse cellular functions. This versatility is essentially due to the fact that RNA molecules can exploit the power of base pairing to allow them to fold into a wide variety of structures through which they can perform diverse roles, but also to selectively target and bind to other nucleic acids. This is true in particular for bacterial small regulatory RNAs that act by imperfect base-pairing with target mRNAs, and thereby control their expression through different mechanisms. Here we outline an overview of in vivo and in vitro approaches that are currently used to gain mechanistic insights into how these sRNAs control gene expression in bacteria.
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139
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Klein G, Stupak A, Biernacka D, Wojtkiewicz P, Lindner B, Raina S. Multiple Transcriptional Factors Regulate Transcription of the rpoE Gene in Escherichia coli under Different Growth Conditions and When the Lipopolysaccharide Biosynthesis Is Defective. J Biol Chem 2016; 291:22999-23019. [PMID: 27629414 DOI: 10.1074/jbc.m116.748954] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Indexed: 12/22/2022] Open
Abstract
The RpoE σ factor is essential for the viability of Escherichia coli RpoE regulates extracytoplasmic functions including lipopolysaccharide (LPS) translocation and some of its non-stoichiometric modifications. Transcription of the rpoE gene is positively autoregulated by EσE and by unknown mechanisms that control the expression of its distally located promoter(s). Mapping of 5' ends of rpoE mRNA identified five new transcriptional initiation sites (P1 to P5) located distal to EσE-regulated promoter. These promoters are activated in response to unique signals. Of these P2, P3, and P4 defined major promoters, recognized by RpoN, RpoD, and RpoS σ factors, respectively. Isolation of trans-acting factors, in vitro transcriptional and gel retardation assays revealed that the RpoN-recognized P2 promoter is positively regulated by a QseE/F two-component system and NtrC activator, whereas the RpoD-regulated P3 promoter is positively regulated by a Rcs system in response to defects in LPS core biosynthesis, overproduction of certain lipoproteins, and the global regulator CRP. Strains synthesizing Kdo2-LA LPS caused up to 7-fold increase in the rpoEP3 activity, which was abrogated in Δ(waaC rcsB). Overexpression of a novel 73-nucleotide sRNA rirA (RfaH interacting RNA) generated by the processing of 5' UTR of the waaQ mRNA induces the rpoEP3 promoter activity concomitant with a decrease in LPS content and defects in the O-antigen incorporation. In the presence of RNA polymerase, RirA binds LPS regulator RfaH known to prevent premature transcriptional termination of waaQ and rfb operons. RirA in excess could titrate out RfaH causing LPS defects and the activation of rpoE transcription.
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Affiliation(s)
- Gracjana Klein
- From the Unit of Bacterial Genetics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland and
| | - Anna Stupak
- From the Unit of Bacterial Genetics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland and
| | - Daria Biernacka
- From the Unit of Bacterial Genetics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland and
| | - Pawel Wojtkiewicz
- From the Unit of Bacterial Genetics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland and
| | - Buko Lindner
- the Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany
| | - Satish Raina
- From the Unit of Bacterial Genetics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland and
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140
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Colgan AM, Kröger C, Diard M, Hardt WD, Puente JL, Sivasankaran SK, Hokamp K, Hinton JCD. The Impact of 18 Ancestral and Horizontally-Acquired Regulatory Proteins upon the Transcriptome and sRNA Landscape of Salmonella enterica serovar Typhimurium. PLoS Genet 2016; 12:e1006258. [PMID: 27564394 PMCID: PMC5001712 DOI: 10.1371/journal.pgen.1006258] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/25/2016] [Indexed: 11/24/2022] Open
Abstract
We know a great deal about the genes used by the model pathogen Salmonella enterica serovar Typhimurium to cause disease, but less about global gene regulation. New tools for studying transcripts at the single nucleotide level now offer an unparalleled opportunity to understand the bacterial transcriptome, and expression of the small RNAs (sRNA) and coding genes responsible for the establishment of infection. Here, we define the transcriptomes of 18 mutants lacking virulence-related global regulatory systems that modulate the expression of the SPI1 and SPI2 Type 3 secretion systems of S. Typhimurium strain 4/74. Using infection-relevant growth conditions, we identified a total of 1257 coding genes that are controlled by one or more regulatory system, including a sub-class of genes that reflect a new level of cross-talk between SPI1 and SPI2. We directly compared the roles played by the major transcriptional regulators in the expression of sRNAs, and discovered that the RpoS (σ38) sigma factor modulates the expression of 23% of sRNAs, many more than other regulatory systems. The impact of the RNA chaperone Hfq upon the steady state levels of 280 sRNA transcripts is described, and we found 13 sRNAs that are co-regulated with SPI1 and SPI2 virulence genes. We report the first example of an sRNA, STnc1480, that is subject to silencing by H-NS and subsequent counter-silencing by PhoP and SlyA. The data for these 18 regulatory systems is now available to the bacterial research community in a user-friendly online resource, SalComRegulon. The transcriptional networks and the functions of small regulatory RNAs of Salmonella enterica serovar Typhimurium are being studied intensively. S. Typhimurium is becoming the ideal model pathogen for linking transcriptional and post-transcriptional gene regulation to bacterial virulence. Here, we systematically defined the regulatory factors responsible for controlling the expression of S. Typhimurium coding genes and sRNAs under infection-relevant growth conditions. As well as confirming published regulatory inputs for Salmonella pathogenicity islands, such as the positive role played by Fur in the expression of SPI1, we report, for the first time, the global impact of the FliZ, HilE and PhoB/R transcription factors and identify 124 sRNAs that belong to virulence-associated regulons. We found a subset of genes of known and unknown function that are regulated by both HilD and SsrB, highlighting the cross-talk mechanisms that control Salmonella virulence. An integrative analysis of the regulatory datasets revealed 5 coding genes of unknown function that may play novel roles in virulence. We hope that the SalComRegulon resource will be a dynamic database that will be constantly updated to inspire new hypothesis-driven experimentation, and will contribute to the construction of a comprehensive transcriptional network for S. Typhimurium.
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Affiliation(s)
- Aoife M. Colgan
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Carsten Kröger
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Médéric Diard
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | | | - José L. Puente
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico
| | - Sathesh K. Sivasankaran
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College, Dublin, Ireland
| | - Jay C. D. Hinton
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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141
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Sievers S, Lund A, Menendez-Gil P, Nielsen A, Storm Mollerup M, Lambert Nielsen S, Buch Larsson P, Borch-Jensen J, Johansson J, Kallipolitis BH. The multicopy sRNA LhrC controls expression of the oligopeptide-binding protein OppA in Listeria monocytogenes. RNA Biol 2016; 12:985-97. [PMID: 26176322 DOI: 10.1080/15476286.2015.1071011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Listeria monocytogenes is the causative agent of the foodborne disease listeriosis. During infection, L. monocytogenes produces an array of non-coding RNAs, including the multicopy sRNA LhrC. These five, nearly identical sRNAs are highly induced in response to cell envelope stress and target the virulence adhesin lapB at the post-transcriptional level. Here, we demonstrate that LhrC controls expression of additional genes encoding cell envelope-associated proteins with virulence function. Using transcriptomics and proteomics, we identified a set of genes affected by LhrC in response to cell envelope stress. Three targets were significantly down-regulated by LhrC at both the RNA and protein level: lmo2349, tcsA and oppA. All three genes encode membrane-associated proteins: A putative substrate binding protein of an amino acid ABC transporter (Lmo2349); the CD4+ T cell-stimulating antigen TcsA, and the oligopeptide binding protein OppA, of which the latter 2 are required for full virulence of L. monocytogenes. For OppA, we show that LhrC acts by direct base paring to the ribosome binding site of the oppA mRNA, leading to an impediment of its translation and a decreased mRNA level. The sRNA-mRNA interaction depends on 2 of 3 CU-rich regions in LhrC allowing binding of 2 oppA mRNAs to a single LhrC molecule. Finally, we found that LhrC contributes to infection in macrophage-like cells. These findings demonstrate a central role for LhrC in controlling the level of OppA and other virulence-associated cell envelope proteins in response to cell envelope stress.
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Affiliation(s)
- Susanne Sievers
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark.,b Institute for Microbiology; Ernst-Moritz-Arndt-University Greifswald ; Greifswald , Germany.,d These authors equally contributed to this work
| | - Anja Lund
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark.,d These authors equally contributed to this work
| | - Pilar Menendez-Gil
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Aaraby Nielsen
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Maria Storm Mollerup
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Stine Lambert Nielsen
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Pernille Buch Larsson
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Jonas Borch-Jensen
- a Department of Biochemistry and Molecular Biology ; University of Southern Denmark ; Odense , Denmark
| | - Jörgen Johansson
- c Department of Molecular Biology ; Umeå University ; Umeå , Sweden
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142
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Fröhlich KS, Haneke K, Papenfort K, Vogel J. The target spectrum of SdsR small RNA in Salmonella. Nucleic Acids Res 2016; 44:10406-10422. [PMID: 27407104 PMCID: PMC5137417 DOI: 10.1093/nar/gkw632] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/11/2016] [Accepted: 06/29/2016] [Indexed: 12/28/2022] Open
Abstract
Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these ‘core sRNAs’ of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σS and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD. However, sdsR genes are present in almost all enterobacterial genomes, suggesting that additional, conserved targets of this sRNA must exist. Here, we have combined SdsR pulse-expression with whole genome transcriptomics to discover 20 previously unknown candidate targets of SdsR which include mRNAs coding for physiologically important regulators such as the carbon utilization regulator, CRP, the nucleoid-associated chaperone, StpA and the antibiotic resistance transporter, TolC. Processing of SdsR by RNase E results in two cellular SdsR variants with distinct target spectra. While the overall physiological role of this orphan core sRNA remains to be fully understood, the new SdsR targets present valuable leads to determine sRNA functions in resting bacteria.
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Affiliation(s)
- Kathrin S Fröhlich
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany.,Department of Biology I, Microbiology, Ludwig-Maximilians-University Munich, D-82152 Martinsried, Germany
| | - Katharina Haneke
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
| | - Kai Papenfort
- Department of Biology I, Microbiology, Ludwig-Maximilians-University Munich, D-82152 Martinsried, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
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143
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Wroblewska Z, Olejniczak M. Hfq assists small RNAs in binding to the coding sequence of ompD mRNA and in rearranging its structure. RNA (NEW YORK, N.Y.) 2016; 22:979-94. [PMID: 27154968 PMCID: PMC4911921 DOI: 10.1261/rna.055251.115] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 04/01/2016] [Indexed: 05/23/2023]
Abstract
The bacterial protein Hfq participates in the regulation of translation by small noncoding RNAs (sRNAs). Several mechanisms have been proposed to explain the role of Hfq in the regulation by sRNAs binding to the 5'-untranslated mRNA regions. However, it remains unknown how Hfq affects those sRNAs that target the coding sequence. Here, the contribution of Hfq to the annealing of three sRNAs, RybB, SdsR, and MicC, to the coding sequence of Salmonella ompD mRNA was investigated. Hfq bound to ompD mRNA with tight, subnanomolar affinity. Moreover, Hfq strongly accelerated the rates of annealing of RybB and MicC sRNAs to this mRNA, and it also had a small effect on the annealing of SdsR. The experiments using truncated RNAs revealed that the contributions of Hfq to the annealing of each sRNA were individually adjusted depending on the structures of interacting RNAs. In agreement with that, the mRNA structure probing revealed different structural contexts of each sRNA binding site. Additionally, the annealing of RybB and MicC sRNAs induced specific conformational changes in ompD mRNA consistent with local unfolding of mRNA secondary structure. Finally, the mutation analysis showed that the long AU-rich sequence in the 5'-untranslated mRNA region served as an Hfq binding site essential for the annealing of sRNAs to the coding sequence. Overall, the data showed that the functional specificity of Hfq in the annealing of each sRNA to the ompD mRNA coding sequence was determined by the sequence and structure of the interacting RNAs.
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Affiliation(s)
- Zuzanna Wroblewska
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznań, 61-614 Poznań, Poland
| | - Mikolaj Olejniczak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznań, 61-614 Poznań, Poland
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144
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Shiver AL, Osadnik H, Kritikos G, Li B, Krogan N, Typas A, Gross CA. A Chemical-Genomic Screen of Neglected Antibiotics Reveals Illicit Transport of Kasugamycin and Blasticidin S. PLoS Genet 2016; 12:e1006124. [PMID: 27355376 PMCID: PMC4927156 DOI: 10.1371/journal.pgen.1006124] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/23/2016] [Indexed: 12/11/2022] Open
Abstract
Fighting antibiotic resistance requires a deeper understanding of the genetic factors that determine the antibiotic susceptibility of bacteria. Here we describe a chemical-genomic screen in Escherichia coli K-12 that was designed to discover new aspects of antibiotic resistance by focusing on a set of 26 antibiotics and other stresses with poorly characterized mode-of-action and determinants of resistance. We show that the screen identifies new resistance determinants for these antibiotics including a common signature from two antimicrobials, kasugamycin and blasticidin S, used to treat crop diseases like rice blast and fire blight. Following this signature, we further investigated the mechanistic basis for susceptibility to kasugamycin and blasticidin S in E. coli using both genetic and biochemical approaches. We provide evidence that these compounds hijack an overlapping set of peptide ABC-importers to enter the bacterial cell. Loss of uptake may be an underappreciated mechanism for the development of kasugamycin resistance in bacterial plant pathogens. Bacterial species differ in their susceptibility to antibiotics but the reason for these differences remains an open question. Understanding the genetic basis of antibiotic susceptibility will be critical for predicting the efficacy of new antibiotics and possibly finding new antibiotic targets. Here we report a large-scale study that connects bacterial genes to antibiotics, using a set of antibiotics that were chosen to include poorly characterized compounds. We discovered genes that confer resistance to a number of neglected antibiotics, expanding our knowledge of gene function and antibiotic resistance in Escherichia coli K-12. Starting from this large-scale screen, we then investigated how two antibiotics with a common history, kasugamycin and blasticidin S, enter bacterial cells. Both mimic naturally occurring nutrients to trick E. coli into actively bringing them inside. Kasugamycin is used to control microbes that cause agricultural diseases and mutations that reduce uptake like those we describe here may be an underappreciated factor in the development of resistance to kasugamycin.
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Affiliation(s)
- Anthony L. Shiver
- Graduate Group in Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Hendrik Osadnik
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, United States of America
| | - George Kritikos
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Bo Li
- Department of Chemistry, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Nevan Krogan
- QB3, California Institute for Quantitative Biosciences, San Francisco, California, United States of America
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California, United States of America
- Gladstone Institutes, San Francisco, California, United States of America
| | - Athanasios Typas
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Carol A. Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, United States of America
- QB3, California Institute for Quantitative Biosciences, San Francisco, California, United States of America
- Department of Cell and Tissue Biology, University of California, San Francisco, California, United States of America
- * E-mail:
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145
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Fröhlich KS, Papenfort K. Interplay of regulatory RNAs and mobile genetic elements in enteric pathogens. Mol Microbiol 2016; 101:701-13. [DOI: 10.1111/mmi.13428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Kathrin S. Fröhlich
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
| | - Kai Papenfort
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
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146
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Hao Y, Updegrove TB, Livingston NN, Storz G. Protection against deleterious nitrogen compounds: role of σS-dependent small RNAs encoded adjacent to sdiA. Nucleic Acids Res 2016; 44:6935-48. [PMID: 27166377 PMCID: PMC5001591 DOI: 10.1093/nar/gkw404] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/02/2016] [Indexed: 11/16/2022] Open
Abstract
Here, we report the characterization of a set of small, regulatory RNAs (sRNAs) expressed from an Escherichia coli locus we have denoted sdsN located adjacent to the LuxR-homolog gene sdiA. Two longer sRNAs, SdsN137 and SdsN178 are transcribed from two σS-dependent promoters but share the same terminator. Low temperature, rich nitrogen sources and the Crl and NarP transcription factors differentially affect the levels of the SdsN transcripts. Whole genome expression analysis after pulse overexpression of SdsN137 and assays of lacZ fusions revealed that the SdsN137 directly represses the synthesis of the nitroreductase NfsA, which catalyzes the reduction of the nitrogroup (NO2) in nitroaromatic compounds and the flavohemoglobin HmpA, which has aerobic nitric oxide (NO) dioxygenase activity. Consistent with this regulation, SdsN137 confers resistance to nitrofurans. In addition, SdsN137 negatively regulates synthesis of NarP. Interestingly, SdsN178 is defective at regulating the above targets due to unusual binding to the Hfq protein, but cleavage leads to a shorter form, SdsN124, able to repress nfsA and hmpA.
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Affiliation(s)
- Yue Hao
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, USA
| | - Taylor B Updegrove
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, USA
| | - Natasha N Livingston
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, 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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147
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Strobel EJ, Watters KE, Loughrey D, Lucks JB. RNA systems biology: uniting functional discoveries and structural tools to understand global roles of RNAs. Curr Opin Biotechnol 2016; 39:182-191. [PMID: 27132125 DOI: 10.1016/j.copbio.2016.03.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/24/2016] [Accepted: 03/31/2016] [Indexed: 12/11/2022]
Abstract
RNAs assume sophisticated structures that are active in myriad cellular processes. In this review, we highlight newly identified ribozymes, riboswitches, and small RNAs, some of which control the function of cellular metabolic and gene expression networks. We then examine recent developments in genome-wide RNA structure probing technologies that are yielding new insights into the structural landscape of the transcriptome. Finally, we discuss how these RNA 'structomic' methods can address emerging questions in RNA systems biology, from the mechanisms behind long non-coding RNAs to new bases for human diseases.
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Affiliation(s)
- Eric J Strobel
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Kyle E Watters
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - David Loughrey
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Julius B Lucks
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States.
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148
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Gifsy-1 Prophage IsrK with Dual Function as Small and Messenger RNA Modulates Vital Bacterial Machineries. PLoS Genet 2016; 12:e1005975. [PMID: 27057757 PMCID: PMC4825925 DOI: 10.1371/journal.pgen.1005975] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 03/14/2016] [Indexed: 11/20/2022] Open
Abstract
While an increasing number of conserved small regulatory RNAs (sRNAs) are known to function in general bacterial physiology, the roles and modes of action of sRNAs from horizontally acquired genomic regions remain little understood. The IsrK sRNA of Gifsy-1 prophage of Salmonella belongs to the latter class. This regulatory RNA exists in two isoforms. The first forms, when a portion of transcripts originating from isrK promoter reads-through the IsrK transcription-terminator producing a translationally inactive mRNA target. Acting in trans, the second isoform, short IsrK RNA, binds the inactive transcript rendering it translationally active. By switching on translation of the first isoform, short IsrK indirectly activates the production of AntQ, an antiterminator protein located upstream of isrK. Expression of antQ globally interferes with transcription termination resulting in bacterial growth arrest and ultimately cell death. Escherichia coli and Salmonella cells expressing AntQ display condensed chromatin morphology and localization of UvrD to the nucleoid. The toxic phenotype of AntQ can be rescued by co-expression of the transcription termination factor, Rho, or RNase H, which protects genomic DNA from breaks by resolving R-loops. We propose that AntQ causes conflicts between transcription and replication machineries and thus promotes DNA damage. The isrK locus represents a unique example of an island-encoded sRNA that exerts a highly complex regulatory mechanism to tune the expression of a toxic protein.
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149
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Holmqvist E, Wright PR, Li L, Bischler T, Barquist L, Reinhardt R, Backofen R, Vogel J. Global RNA recognition patterns of post-transcriptional regulators Hfq and CsrA revealed by UV crosslinking in vivo. EMBO J 2016; 35:991-1011. [PMID: 27044921 PMCID: PMC5207318 DOI: 10.15252/embj.201593360] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/26/2016] [Indexed: 12/22/2022] Open
Abstract
The molecular roles of many RNA‐binding proteins in bacterial post‐transcriptional gene regulation are not well understood. Approaches combining in vivo UV crosslinking with RNA deep sequencing (CLIP‐seq) have begun to revolutionize the transcriptome‐wide mapping of eukaryotic RNA‐binding protein target sites. We have applied CLIP‐seq to chart the target landscape of two major bacterial post‐transcriptional regulators, Hfq and CsrA, in the model pathogen Salmonella Typhimurium. By detecting binding sites at single‐nucleotide resolution, we identify RNA preferences and structural constraints of Hfq and CsrA during their interactions with hundreds of cellular transcripts. This reveals 3′‐located Rho‐independent terminators as a universal motif involved in Hfq–RNA interactions. Additionally, Hfq preferentially binds 5′ to sRNA‐target sites in mRNAs, and 3′ to seed sequences in sRNAs, reflecting a simple logic in how Hfq facilitates sRNA–mRNA interactions. Importantly, global knowledge of Hfq sites significantly improves sRNA‐target predictions. CsrA binds AUGGA sequences in apical loops and targets many Salmonella virulence mRNAs. Overall, our generic CLIP‐seq approach will bring new insights into post‐transcriptional gene regulation by RNA‐binding proteins in diverse bacterial species.
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Affiliation(s)
- Erik Holmqvist
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Patrick R Wright
- Bioinformatics Group, Department of Computer Science, Albert Ludwig University Freiburg, Freiburg, Germany
| | - Lei Li
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Thorsten Bischler
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Lars Barquist
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Richard Reinhardt
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, Albert Ludwig University Freiburg, Freiburg, Germany BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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150
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Sin C, Chiarugi D, Valleriani A. Quantitative assessment of ribosome drop-off in E. coli. Nucleic Acids Res 2016; 44:2528-37. [PMID: 26935582 PMCID: PMC4824120 DOI: 10.1093/nar/gkw137] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/24/2016] [Indexed: 11/14/2022] Open
Abstract
Premature ribosome drop-off is one of the major errors in translation of mRNA by ribosomes. However, repeated analyses of Ribo-seq data failed to quantify its strength inE. coli Relying on a novel highly sensitive data analysis method we show that a significant rate of ribosome drop-off is measurable and can be quantified also when cells are cultured under non-stressing conditions. Moreover, we find that the drop-off rate is highly variable, depending on multiple factors. In particular, under environmental stress such as amino acid starvation or ethanol intoxication, the drop-off rate markedly increases.
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Affiliation(s)
- Celine Sin
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Davide Chiarugi
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Angelo Valleriani
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
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