1
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Zhu W, Xi L, Qiao J, Du D, Wang Y, Morigen. Involvement of OxyR and Dps in the repression of replication initiation by DsrA small RNA in Escherichia coli. Gene 2023; 882:147659. [PMID: 37482259 DOI: 10.1016/j.gene.2023.147659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
Regulation of the cell cycle process is an effective measure to ensure the stability and fidelity of genetic material during the reproduction of bacteria under different stresses. The small RNA DsrA helps bacteria adapt to environments by binding to multiple targets, but its association with the cell cycle remains unclear. Detection by flow cytometry, we first found that the knockout of dsrA promoted replication initiation, and corresponding overexpression of DsrA inhibited replication initiation in Escherichia coli. The absence of the chaperone protein Hfq, the DNA replication negative regulator protein Dps, or the transcription factor OxyR, was found to cause DsrA to no longer inhibit replication initiation. Excess DsrA promotes expression of the oxyR and dps gene, whereas β-galactosidase activity assay showed that deleting oxyR limited the enhancement of dps promoter transcriptional activity by DsrA. OxyR is a known positive regulator of Dps. Our data suggests that the effect of DsrA on replication initiation requires Hfq and that the upregulation of Dps expression by OxyR in response to DsrA levels may be a potential regulatory pathway for the negative regulation of DNA replication initiation.
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Affiliation(s)
- Weiwei Zhu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Lingjun Xi
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Jiaxin Qiao
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Dongdong Du
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Yao Wang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Morigen
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China.
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2
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Carrier MC, Lalaouna D, Massé E. Hfq protein and GcvB small RNA tailoring of oppA target mRNA to levels allowing translation activation by MicF small RNA in Escherichia coli. RNA Biol 2023; 20:59-76. [PMID: 36860088 PMCID: PMC9988348 DOI: 10.1080/15476286.2023.2179582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
Traffic of molecules across the bacterial membrane mainly relies on porins and transporters, whose expression must adapt to environmental conditions. To ensure bacterial fitness, synthesis and assembly of functional porins and transporters are regulated through a plethora of mechanisms. Among them, small regulatory RNAs (sRNAs) are known to be powerful post-transcriptional regulators. In Escherichia coli, the MicF sRNA is known to regulate only four targets, a very narrow targetome for a sRNA responding to various stresses, such as membrane stress, osmotic shock, or thermal shock. Using an in vivo pull-down assay combined with high-throughput RNA sequencing, we sought to identify new targets of MicF to better understand its role in the maintenance of cellular homoeostasis. Here, we report the first positively regulated target of MicF, the oppA mRNA. The OppA protein is the periplasmic component of the Opp ATP-binding cassette (ABC) oligopeptide transporter and regulates the import of short peptides, some of them bactericides. Mechanistic studies suggest that oppA translation is activated by MicF through a mechanism of action involving facilitated access to a translation-enhancing region in oppA 5'UTR. Intriguingly, MicF activation of oppA translation depends on cross-regulation by negative trans-acting effectors, the GcvB sRNA and the RNA chaperone protein Hfq.
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Affiliation(s)
- Marie-Claude Carrier
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - David Lalaouna
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Eric Massé
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
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3
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Balakrishnan R, Mori M, Segota I, Zhang Z, Aebersold R, Ludwig C, Hwa T. Principles of gene regulation quantitatively connect DNA to RNA and proteins in bacteria. Science 2022; 378:eabk2066. [PMID: 36480614 PMCID: PMC9804519 DOI: 10.1126/science.abk2066] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein concentrations are set by a complex interplay between gene-specific regulatory processes and systemic factors, including cell volume and shared gene expression machineries. Elucidating this interplay is crucial for discerning and designing gene regulatory systems. We quantitatively characterized gene-specific and systemic factors that affect transcription and translation genome-wide for Escherichia coli across many conditions. The results revealed two design principles that make regulation of gene expression insulated from concentrations of shared machineries: RNA polymerase activity is fine-tuned to match translational output, and translational characteristics are similar across most messenger RNAs (mRNAs). Consequently, in bacteria, protein concentration is set primarily at the promoter level. A simple mathematical formula relates promoter activities and protein concentrations across growth conditions, enabling quantitative inference of gene regulation from omics data.
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Affiliation(s)
- Rohan Balakrishnan
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374
| | - Matteo Mori
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374
| | - Igor Segota
- Departments of Medicine and Pharmacology, University of California at San Diego, La Jolla, California 92093
| | - Zhongge Zhang
- Section of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093
| | - Ruedi Aebersold
- Faculty of Science, University of Zurich, Zurich, Switzerland.,Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Switzerland
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University of Munich (TUM), Freising, Germany
| | - Terence Hwa
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374.,Section of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093.,CORRESPONDING AUTHOR: Terence Hwa ()
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4
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Cossa A, Trépout S, Wien F, Groen J, Le Brun E, Turbant F, Besse L, Pereiro E, Arluison V. Cryo soft X-ray tomography to explore Escherichia coli nucleoid remodeling by Hfq master regulator. J Struct Biol 2022; 214:107912. [PMID: 36283630 DOI: 10.1016/j.jsb.2022.107912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 09/28/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022]
Abstract
The bacterial chromosomic DNA is packed within a membrane-less structure, the nucleoid, due to the association of DNA with proteins called Nucleoid Associated Proteins (NAPs). Among these NAPs, Hfq is one of the most intriguing as it plays both direct and indirect roles on DNA structure. Indeed, Hfq is best known to mediate post-transcriptional regulation by using small noncoding RNA (sRNA). Although Hfq presence in the nucleoid has been demonstrated for years, its precise role is still unclear. Recently, it has been shown in vitro that Hfq forms amyloid-like structures through its C-terminal region, hence belonging to the bridging family of NAPs. Here, using cryo soft X-ray tomography imaging of native unlabeled cells and using a semi-automatic analysis and segmentation procedure, we show that Hfq significantly remodels the Escherichia coli nucleoid. More specifically, Hfq influences nucleoid density especially during the stationary growth phase when it is more abundant. Our results indicate that Hfq could regulate nucleoid compaction directly via its interaction with DNA, but also at the post-transcriptional level via its interaction with RNAs. Taken together, our findings reveal a new role for this protein in nucleoid remodeling in vivo, that may serve in response to stress conditions and in adapting to changing environments.
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Affiliation(s)
- Antoine Cossa
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France; Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Sylvain Trépout
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France; Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria 3800, Australia.
| | - Frank Wien
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France
| | - Johannes Groen
- Mistral Beamline, Alba Light Source, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Etienne Le Brun
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; Department of Molecular Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Laetitia Besse
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France
| | - Eva Pereiro
- Mistral Beamline, Alba Light Source, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; Université Paris Cité, UFR Sciences du vivant, 75006 Paris cedex, France.
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5
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DsrA Modulates Central Carbon Metabolism and Redox Balance by Directly Repressing pflB Expression in Salmonella Typhimurium. Microbiol Spectr 2022; 10:e0152221. [PMID: 35107349 PMCID: PMC8809350 DOI: 10.1128/spectrum.01522-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacterial small RNAs (sRNAs) function as vital regulators in response to various environmental stresses by base pairing with target mRNAs. The sRNA DsrA, an important posttranscriptional regulator, has been reported to play a crucial role in defense against oxidative stress in Salmonella enterica serovar Typhimurium, but its regulatory mechanism remains unclear. The transcriptome sequencing (RNA-seq) results in this study showed that the genes involved in glycolysis, pyruvate metabolism, the tricarboxylic acid (TCA) cycle, and NADH-dependent respiration exhibited significantly different expression patterns between S. Typhimurium wild type (WT) and the dsrA deletion mutant (ΔdsrA strain) before and after H2O2 treatment. This indicated the importance of DsrA in regulating central carbon metabolism (CCM) and NAD(H) homeostasis of S. Typhimurium. To reveal the direct target of DsrA action, fusion proteins of six candidate genes (acnA, srlE, tdcB, nuoH, katG, and pflB) with green fluorescent protein (GFP) were constructed, and the fluorescence analysis showed that the expression of pflB encoding pyruvate-formate lyase was repressed by DsrA. Furthermore, site-directed mutagenesis and RNase E-dependent experiments showed that the direct base pairing of DsrA with pflB mRNA could recruit RNase E to degrade pflB mRNA and reduce the stability of pflB mRNA. In addition, the NAD+/NADH ratio in WT-ppflB-pdsrA was significantly lower than that in WT-ppflB, suggesting that the repression of pflB by DsrA could contribute greatly to the redox balance in S. Typhimurium. Taken together, a novel target of DsrA was identified, and its regulatory role was clarified, which demonstrated that DsrA could modulate CCM and redox balance by directly repressing pflB expression in S. Typhimurium. IMPORTANCE Small RNA DsrA plays an important role in defending against oxidative stress in bacteria. In this study, we identified a novel target (pflB, encoding pyruvate-formate lyase) of DsrA and demonstrated its potential regulatory mechanism in S. Typhimurium by transcriptome analysis. In silico prediction revealed a direct base pairing between DsrA and pflB mRNA, which was confirmed in site-directed mutagenesis experiments. The interaction of DsrA-pflB mRNA could greatly contribute to the regulation of central carbon metabolism and intracellular redox balance in S. Typhimurium. These findings provided a better understanding of the critical roles of small RNA in central metabolism and stress responses in foodborne pathogens.
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6
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Tepavčević J, Yarrington K, Fung B, Lin X, Visick KL. sRNA chaperone Hfq controls bioluminescence and other phenotypes through Qrr1-dependent and -independent mechanisms in Vibrio fischeri. Gene X 2022; 809:146048. [PMID: 34756963 PMCID: PMC8673744 DOI: 10.1016/j.gene.2021.146048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 10/26/2021] [Indexed: 02/01/2023] Open
Abstract
Colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri depends on bacterial biofilm formation, motility, and bioluminescence. Previous work has demonstrated an inhibitory role for the small RNA (sRNA) Qrr1 in quorum-induced bioluminescence of V. fischeri, but the contribution of the corresponding sRNA chaperone, Hfq, was not examined. We thus hypothesized that V. fischeri Hfq similarly functions to inhibit bacterial bioluminescence as well as regulate other key steps of symbiosis, including bacterial biofilm formation and motility. Surprisingly, deletion of hfq increased luminescence of V. fischeri beyond what was observed for the loss of qrr1 sRNA. Epistasis experiments revealed that, while Hfq contributes to the Qrr1-dependent regulation of light production, it also functions independently of Qrr1 and its downstream target, LitR. This Hfq-dependent, Qrr1-independent regulation of bioluminescence is also independent of the major repressor of light production in V. fischeri, ArcA. We further determined that Hfq is required for full motility of V. fischeri in a mechanism that partially depends on the Qrr1/LitR regulators. Finally, Hfq also appears to function in the control of biofilm formation: loss of Hfq delayed the timing and diminished the extent of wrinkled colony development, but did not eliminate the production of SYP-polysaccharide-dependent cohesive colonies. Furthermore, loss of Hfq enhanced production of cellulose and resulted in increased Congo red binding. Together, these findings point to Hfq as an important regulator of multiple phenotypes relevant to symbiosis between V. fischeri and its squid host.
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Affiliation(s)
- Jovanka Tepavčević
- Department of Biology, Wheaton College, Wheaton, Illinois, USA,Corresponding author
| | - Kaiti Yarrington
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Brittany Fung
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
| | - Xijin Lin
- Department of Biology, Wheaton College, Wheaton, Illinois, USA
| | - Karen L. Visick
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
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7
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Naskulwar K, Peña-Castillo L. sRNARFTarget: a fast machine-learning-based approach for transcriptome-wide sRNA target prediction. RNA Biol 2021; 19:44-54. [PMID: 34965197 PMCID: PMC8794260 DOI: 10.1080/15476286.2021.2012058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) are key regulators of gene expression in many processes related to adaptive responses. A multitude of sRNAs have been identified in many bacterial species; however, their function has yet to be elucidated. A key step to understand sRNAs function is to identify the mRNAs these sRNAs bind to. There are several computational methods for sRNA target prediction, and the most accurate one is CopraRNA which is based on comparative-genomics. However, species-specific sRNAs are quite common and CopraRNA cannot be used for these sRNAs. The most commonly used transcriptome-wide sRNA target prediction method and second-most-accurate method is IntaRNA. However, IntaRNA can take hours to run on a bacterial transcriptome. Here we present sRNARFTarget, a machine-learning-based method for transcriptome-wide sRNA target prediction applicable to any sRNA. We comparatively assessed the performance of sRNARFTarget, CopraRNA and IntaRNA in three bacterial species. Our results show that sRNARFTarget outperforms IntaRNA in terms of accuracy, ranking of true interacting pairs, and running time. However, CopraRNA substantially outperforms the other two programsin terms of accuracy. Thus, we suggest using CopraRNA when homolog sequences of the sRNA are available, and sRNARFTarget for transcriptome-wide prediction or for species-specific sRNAs. sRNARFTarget is available at https://github.com/BioinformaticsLabAtMUN/sRNARFTarget.
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Affiliation(s)
- Kratika Naskulwar
- Department of Computer Science, Memorial University of Newfoundland, St. John's, Canada
| | - Lourdes Peña-Castillo
- Department of Computer Science, Memorial University of Newfoundland, St. John's, Canada.,Department of Biology, Memorial University of Newfoundland, St. John's, Canada
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8
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Sauder AB, Kendall MM. A pathogen-specific sRNA influences enterohemorrhagic Escherichia coli fitness and virulence in part by direct interaction with the transcript encoding the ethanolamine utilization regulatory factor EutR. Nucleic Acids Res 2021; 49:10988-11004. [PMID: 34591974 PMCID: PMC8565329 DOI: 10.1093/nar/gkab863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 01/07/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 relies on sRNAs to coordinate expression of metabolic and virulence factors to colonize the host. Here, we focus on the sRNA, named MavR (metabolism and virulence regulator), that is conserved among pathogenic Enterobacteriaceae. MavR is constitutively expressed under in vitro conditions that promote EHEC virulence gene expression. Using MS2-affinity purification coupled with RNA sequencing, the eutR transcript was identified as a putative target of MavR. EutR is a transcription factor that promotes expression of genes required for ethanolamine metabolism as well as virulence factors important for host colonization. MavR binds to the eutR coding sequence to protect the eutR transcript from RNase E-mediated degradation. Ultimately, MavR promotes EutR expression and in turn ethanolamine utilization and ethanolamine-dependent growth. RNAseq analyses revealed that MavR also affected expression of genes important for other metabolic pathways, motility, oxidative stress and attaching and effacing lesion formation, which contribute to EHEC colonization of the gastrointestinal tract. In support of the idea that MavR-dependent gene expression affects fitness during infection, deletion of mavR resulted in significant (∼10- to 100-fold) attenuation in colonization of the mammalian intestine. Altogether, these studies reveal an important, extensive, and robust phenotype for a bacterial sRNA in host-pathogen interactions.
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Affiliation(s)
- Amber B Sauder
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Melissa M Kendall
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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9
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Evguenieva-Hackenberg E. Riboregulation in bacteria: From general principles to novel mechanisms of the trp attenuator and its sRNA and peptide products. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1696. [PMID: 34651439 DOI: 10.1002/wrna.1696] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/25/2021] [Accepted: 09/10/2021] [Indexed: 12/26/2022]
Abstract
Gene expression strategies ensuring bacterial survival and competitiveness rely on cis- and trans-acting RNA-regulators (riboregulators). Among the cis-acting riboregulators are transcriptional and translational attenuators, and antisense RNAs (asRNAs). The trans-acting riboregulators are small RNAs (sRNAs) that bind proteins or base pairs with other RNAs. This classification is artificial since some regulatory RNAs act both in cis and in trans, or function in addition as small mRNAs. A prominent example is the archetypical, ribosome-dependent attenuator of tryptophan (Trp) biosynthesis genes. It responds by transcription attenuation to two signals, Trp availability and inhibition of translation, and gives rise to two trans-acting products, the attenuator sRNA rnTrpL and the leader peptide peTrpL. In Escherichia coli, rnTrpL links Trp availability to initiation of chromosome replication and in Sinorhizobium meliloti, it coordinates regulation of split tryptophan biosynthesis operons. Furthermore, in S. meliloti, peTrpL is involved in mRNA destabilization in response to antibiotic exposure. It forms two types of asRNA-containing, antibiotic-dependent ribonucleoprotein complexes (ARNPs), one of them changing the target specificity of rnTrpL. The posttranscriptional role of peTrpL indicates two emerging paradigms: (1) sRNA reprograming by small molecules and (2) direct involvement of antibiotics in regulatory RNPs. They broaden our view on RNA-based mechanisms and may inspire new approaches for studying, detecting, and using antibacterial compounds. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.
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10
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Binding of the RNA Chaperone Hfq on Target mRNAs Promotes the Small RNA RyhB-Induced Degradation in Escherichia coli. Noncoding RNA 2021; 7:ncrna7040064. [PMID: 34698252 PMCID: PMC8544716 DOI: 10.3390/ncrna7040064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/03/2021] [Accepted: 09/20/2021] [Indexed: 11/16/2022] Open
Abstract
Many RNA-RNA interactions depend on molecular chaperones to form and remain stable in living cells. A prime example is the RNA chaperone Hfq, which is a critical effector involved in regulatory interactions between small RNAs (sRNAs) and cognate target mRNAs in Enterobacteriaceae. While there is a great deal of in vitro biochemical evidence supporting the model that Hfq enhances rates or affinities of sRNA:mRNA interactions, there is little corroborating in vivo evidence. Here we used in vivo tools including reporter genes, co-purification assays, and super-resolution microscopy to analyze the role of Hfq in RyhB-mediated regulation, and we found that Hfq is often unnecessary for efficient RyhB:mRNA complex formation in vivo. Remarkably, our data suggest that a primary function of Hfq is to promote RyhB-induced cleavage of mRNA targets by RNase E. Moreover, our work indicates that Hfq plays a more limited role in dictating regulatory outcomes following sRNAs RybB and DsrA complex formation with specific target mRNAs. Our investigation helps evaluate the roles played by Hfq in some RNA-mediated regulation.
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11
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Turbant F, Wu P, Wien F, Arluison V. The Amyloid Region of Hfq Riboregulator Promotes DsrA: rpoS RNAs Annealing. BIOLOGY 2021; 10:biology10090900. [PMID: 34571778 PMCID: PMC8468756 DOI: 10.3390/biology10090900] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/30/2021] [Accepted: 09/05/2021] [Indexed: 11/16/2022]
Abstract
Hfq is a bacterial RNA chaperone which promotes the pairing of small noncoding RNAs to target mRNAs, allowing post-transcriptional regulation. This RNA annealing activity has been attributed for years to the N-terminal region of the protein that forms a toroidal structure with a typical Sm-fold. Nevertheless, many Hfqs, including that of Escherichia coli, have a C-terminal region with unclear functions. Here we use a biophysical approach, Synchrotron Radiation Circular Dichroism (SRCD), to probe the interaction of the E. coli Hfq C-terminal amyloid region with RNA and its effect on RNA annealing. This C-terminal region of Hfq, which has been described to be dispensable for sRNA:mRNA annealing, has an unexpected and significant effect on this activity. The functional consequences of this novel property of the amyloid region of Hfq in relation to physiological stress are discussed.
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Affiliation(s)
- Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France;
| | - Pengzhi Wu
- Department of Biology, ETH Zürich, 8093 Zürich, Switzerland;
| | - Frank Wien
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France
- Correspondence: (F.W.); or (V.A.); Tel.: +33-(0)169359665 (F.W.); +33-(0)169083282 (V.A.)
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France;
- UFR Sciences du Vivant, Université de Paris, 75006 Paris, France
- Correspondence: (F.W.); or (V.A.); Tel.: +33-(0)169359665 (F.W.); +33-(0)169083282 (V.A.)
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12
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Smallets S, Kendall MM. Post-transcriptional regulation in attaching and effacing pathogens: integration of environmental cues and the impact on gene expression and host interactions. Curr Opin Microbiol 2021; 63:238-243. [PMID: 34450388 DOI: 10.1016/j.mib.2021.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/04/2021] [Indexed: 11/25/2022]
Abstract
To establish infection, enteric pathogens integrate environmental cues to navigate the gastrointestinal tract and precisely control expression of virulence determinants. Emerging data indicate that post-transcriptional and post-translational gene regulation plays a key role in virulence regulation and pathogen adaptation to the host environment. Here, we highlight recent studies that reveal how physiologically relevant signals initiate post-transcriptional and post-translational regulatory circuits and the impact on virulence gene expression in the attaching and effacing pathogens, enteropathogenic Escherichia coli, enterohemorrhagic E. coli O157:H7, and Citrobacter rodentium.
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Affiliation(s)
- Sarah Smallets
- Department of Biology, University of Virginia, 485 McCormick Rd., Charlottesville, VA, 22904, USA
| | - Melissa M Kendall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave., Charlottesville, VA, 22908, USA.
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13
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Wu Y, Wang S, Nie W, Wang P, Fu L, Ahmad I, Zhu B, Chen G. A key antisense sRNA modulates the oxidative stress response and virulence in Xanthomonas oryzae pv. oryzicola. PLoS Pathog 2021; 17:e1009762. [PMID: 34297775 PMCID: PMC8336823 DOI: 10.1371/journal.ppat.1009762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/04/2021] [Accepted: 06/27/2021] [Indexed: 11/18/2022] Open
Abstract
Pathogens integrate multiple environmental signals to navigate the host and control the expression of virulence genes. In this process, small regulatory noncoding RNAs (sRNAs) may function in gene expression as post-transcriptional regulators. In this study, the sRNA Xonc3711 functioned in the response of the rice pathogen, Xanthomonas oryzae pv. oryzicola (Xoc), to oxidative stress. Xonc3711 repressed production of the DNA-binding protein Xoc_3982 by binding to the xoc_3982 mRNA within the coding region. Mutational analysis showed that regulation required an antisense interaction between Xonc3711 and xoc_3982 mRNA, and RNase E was needed for degradation of the xoc_3982 transcript. Deletion of Xonc3711 resulted in a lower tolerance to oxidative stress due to the repression of flagella-associated genes and reduced biofilm formation. Furthermore, ChIP-seq and electrophoretic mobility shift assays showed that Xoc_3982 repressed the transcription of effector xopC2, which contributes to virulence in Xoc BLS256. This study describes how sRNA Xonc3711 modulates multiple traits in Xoc via signals perceived from the external environment. Small, stable RNA species perform diverse functions in both prokaryotes and eukaryotes. In this study, the sRNA Xonc3711 decreased the production of DNA-binding protein Xoc_3982 in the bacterium Xanthomonas oryzae pv. oryzicola (Xoc) by base pairing with the xoc_3982 transcript. When Xonc3711 was mutated, Xoc was impaired in its ability to form flagella and produce biofilms, which reduced Xoc tolerance to oxidative stress. We also discovered that the DNA-binding protein Xoc_3982 represses the expression of xopC2, which encodes an effector protein, and reduces its expression. Our results show that Xonc3711 modulates and integrates multiple systems in Xoc to protect cells from oxidative damage.
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Affiliation(s)
- Yan Wu
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Wenhan Nie
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Peihong Wang
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Luoyi Fu
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Iftikhar Ahmad
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, Pakistan
| | - Bo Zhu
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (BZ); (GC)
| | - Gongyou Chen
- Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai Cooperative Innovation Center for Modern Seed Industry, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (BZ); (GC)
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14
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Mihailovic MK, Ekdahl AM, Chen A, Leistra AN, Li B, González Martínez J, Law M, Ejindu C, Massé É, Freddolino PL, Contreras LM. Uncovering Transcriptional Regulators and Targets of sRNAs Using an Integrative Data-Mining Approach: H-NS-Regulated RseX as a Case Study. Front Cell Infect Microbiol 2021; 11:696533. [PMID: 34327153 PMCID: PMC8313858 DOI: 10.3389/fcimb.2021.696533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial small RNAs (sRNAs) play a vital role in pathogenesis by enabling rapid, efficient networks of gene attenuation during infection. In recent decades, there has been a surge in the number of proposed and biochemically-confirmed sRNAs in both Gram-positive and Gram-negative pathogens. However, limited homology, network complexity, and condition specificity of sRNA has stunted complete characterization of the activity and regulation of these RNA regulators. To streamline the discovery of the expression of sRNAs, and their post-transcriptional activities, we propose an integrative in vivo data-mining approach that couples DNA protein occupancy, RNA-seq, and RNA accessibility data with motif identification and target prediction algorithms. We benchmark the approach against a subset of well-characterized E. coli sRNAs for which a degree of in vivo transcriptional regulation and post-transcriptional activity has been previously reported, finding support for known regulation in a large proportion of this sRNA set. We showcase the abilities of our method to expand understanding of sRNA RseX, a known envelope stress-linked sRNA for which a cellular role has been elusive due to a lack of native expression detection. Using the presented approach, we identify a small set of putative RseX regulators and targets for experimental investigation. These findings have allowed us to confirm native RseX expression under conditions that eliminate H-NS repression as well as uncover a post-transcriptional role of RseX in fimbrial regulation. Beyond RseX, we uncover 163 putative regulatory DNA-binding protein sites, corresponding to regulation of 62 sRNAs, that could lead to new understanding of sRNA transcription regulation. For 32 sRNAs, we also propose a subset of top targets filtered by engagement of regions that exhibit binding site accessibility behavior in vivo. We broadly anticipate that the proposed approach will be useful for sRNA-reliant network characterization in bacteria. Such investigations under pathogenesis-relevant environmental conditions will enable us to deduce complex rapid-regulation schemes that support infection.
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Affiliation(s)
- Mia K Mihailovic
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Alyssa M Ekdahl
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Angela Chen
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Abigail N Leistra
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Bridget Li
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Javier González Martínez
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Matthew Law
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Cindy Ejindu
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Éric Massé
- Department of Biochemistry and Functional Genomics, Universitéde Sherbrooke, RNA Group, Sherbrooke, QC, Canada
| | - Peter L Freddolino
- Department of Biological Chemistry and Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
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15
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Carrier MC, Ng Kwan Lim E, Jeannotte G, Massé E. Trans-Acting Effectors Versus RNA Cis-Elements: A Tightly Knit Regulatory Mesh. Front Microbiol 2021; 11:609237. [PMID: 33384678 PMCID: PMC7769764 DOI: 10.3389/fmicb.2020.609237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/10/2020] [Indexed: 11/13/2022] Open
Abstract
Prokaryotic organisms often react instantly to environmental variations to ensure their survival. They can achieve this by rapidly and specifically modulating translation, the critical step of protein synthesis. The translation machinery responds to an array of cis-acting elements, located on the RNA transcript, which dictate the fate of mRNAs. These cis-encoded elements, such as RNA structures or sequence motifs, interact with a variety of regulators, among them small regulatory RNAs. These small regulatory RNAs (sRNAs) are especially effective at modulating translation initiation through their interaction with cis-encoded mRNA elements. Here, through selected examples of canonical and non-canonical regulatory events, we demonstrate the intimate connection between mRNA cis-encoded features and sRNA-dependent translation regulation. We also address how sRNA-based mechanistic studies can drive the discovery of new roles for cis-elements. Finally, we briefly overview the challenges of using translation regulation by synthetic regulators as a tool.
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Affiliation(s)
- Marie-Claude Carrier
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Evelyne Ng Kwan Lim
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Gabriel Jeannotte
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- Department of Biochemistry and Functional Genomics, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
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16
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Lott SC, Voigt K, Lambrecht SJ, Hess WR, Steglich C. A framework for the computational prediction and analysis of non-coding RNAs in microbial environmental populations and their experimental validation. THE ISME JOURNAL 2020; 14:1955-1965. [PMID: 32346084 PMCID: PMC7368042 DOI: 10.1038/s41396-020-0658-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 03/22/2020] [Accepted: 04/07/2020] [Indexed: 11/09/2022]
Abstract
Small regulatory RNAs and antisense RNAs play important roles in the regulation of gene expression in bacteria but are underexplored, especially in natural populations. While environmentally relevant microbes often are not amenable to genetic manipulation or cannot be cultivated in the laboratory, extensive metagenomic and metatranscriptomic datasets for these organisms might be available. Hence, dedicated workflows for specific analyses are needed to fully benefit from this information. Here, we identified abundant sRNAs from oceanic environmental populations of the ecologically important primary producer Prochlorococcus starting from a metatranscriptomic differential RNA-Seq (mdRNA-Seq) dataset. We tracked their homologs in laboratory isolates, and we provide a framework for their further detailed characterization. Several of the experimentally validated sRNAs responded to ecologically relevant changes in cultivation conditions. The expression of the here newly discovered sRNA Yfr28 was highly stimulated in low-nitrogen conditions. Its predicted top targets include mRNAs encoding cell division proteins, a sigma factor, and several enzymes and transporters, suggesting a pivotal role of Yfr28 in the coordination of primary metabolism and cell division. A cis-encoded antisense RNA was identified as a possible positive regulator of atpF encoding subunit b' of the ATP synthase complex. The presented workflow will also be useful for other environmentally relevant microorganisms for which experimental validation abilities are frequently limiting although there is wealth of sequence information available.
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Affiliation(s)
- Steffen C Lott
- University of Freiburg, Faculty of Biology, D-79104, Freiburg, Germany
| | - Karsten Voigt
- University of Freiburg, Faculty of Biology, D-79104, Freiburg, Germany
| | - S Joke Lambrecht
- University of Freiburg, Faculty of Biology, D-79104, Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, D-79104, Freiburg, Germany
| | - Claudia Steglich
- University of Freiburg, Faculty of Biology, D-79104, Freiburg, Germany.
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17
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Iosub IA, van Nues RW, McKellar SW, Nieken KJ, Marchioretto M, Sy B, Tree JJ, Viero G, Granneman S. Hfq CLASH uncovers sRNA-target interaction networks linked to nutrient availability adaptation. eLife 2020; 9:54655. [PMID: 32356726 PMCID: PMC7213987 DOI: 10.7554/elife.54655] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/30/2020] [Indexed: 01/10/2023] Open
Abstract
By shaping gene expression profiles, small RNAs (sRNAs) enable bacteria to efficiently adapt to changes in their environment. To better understand how Escherichia coli acclimatizes to nutrient availability, we performed UV cross-linking, ligation and sequencing of hybrids (CLASH) to uncover Hfq-associated RNA-RNA interactions at specific growth stages. We demonstrate that Hfq CLASH robustly captures bona fide RNA-RNA interactions. We identified hundreds of novel sRNA base-pairing interactions, including many sRNA-sRNA interactions and involving 3’UTR-derived sRNAs. We rediscovered known and identified novel sRNA seed sequences. The sRNA-mRNA interactions identified by CLASH have strong base-pairing potential and are highly enriched for complementary sequence motifs, even those supported by only a few reads. Yet, steady state levels of most mRNA targets were not significantly affected upon over-expression of the sRNA regulator. Our results reinforce the idea that the reproducibility of the interaction, not base-pairing potential, is a stronger predictor for a regulatory outcome.
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Affiliation(s)
- Ira Alexandra Iosub
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Stuart William McKellar
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Karen Jule Nieken
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Brandon Sy
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Jai Justin Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | | | - Sander Granneman
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom
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18
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Desgranges E, Caldelari I, Marzi S, Lalaouna D. Navigation through the twists and turns of RNA sequencing technologies: Application to bacterial regulatory RNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194506. [PMID: 32068131 DOI: 10.1016/j.bbagrm.2020.194506] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/20/2022]
Abstract
Discovered in the 1980s, small regulatory RNAs (sRNAs) are now considered key actors in virtually all aspects of bacterial physiology and virulence. Together with transcriptional and translational regulatory proteins, they integrate and often are hubs of complex regulatory networks, responsible for bacterial response/adaptation to various perceived stimuli. The recent development of powerful RNA sequencing technologies has facilitated the identification and characterization of sRNAs (length, structure and expression conditions) and their RNA targets in several bacteria. Nevertheless, it could be very difficult for non-experts to understand the advantages and drawbacks related to each offered option and, consequently, to make an informed choice. Therefore, the main goal of this review is to provide a guide to navigate through the twists and turns of high-throughput RNA sequencing technologies, with a specific focus on those applied to the study of sRNAs. This article is part of a Special Issue entitled: RNA and gene control in bacteria edited by Dr. M. Guillier and F. Repoila.
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Affiliation(s)
- Emma Desgranges
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - Stefano Marzi
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - David Lalaouna
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France.
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19
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Georg J, Lalaouna D, Hou S, Lott SC, Caldelari I, Marzi S, Hess WR, Romby P. The power of cooperation: Experimental and computational approaches in the functional characterization of bacterial sRNAs. Mol Microbiol 2019; 113:603-612. [PMID: 31705780 PMCID: PMC7154689 DOI: 10.1111/mmi.14420] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/30/2019] [Accepted: 11/06/2019] [Indexed: 12/17/2022]
Abstract
Trans‐acting small regulatory RNAs (sRNAs) are key players in the regulation of gene expression in bacteria. There are hundreds of different sRNAs in a typical bacterium, which in contrast to eukaryotic microRNAs are more heterogeneous in length, sequence composition, and secondary structure. The vast majority of sRNAs function post‐transcriptionally by binding to other RNAs (mRNAs, sRNAs) through rather short regions of imperfect sequence complementarity. Besides, every single sRNA may interact with dozens of different target RNAs and impact gene expression either negatively or positively. These facts contributed to the view that the entirety of the regulatory targets of a given sRNA, its targetome, is challenging to identify. However, recent developments show that a more comprehensive sRNAs targetome can be achieved through the combination of experimental and computational approaches. Here, we give a short introduction into these methods followed by a description of two sRNAs, RyhB, and RsaA, to illustrate the particular strengths and weaknesses of these approaches in more details. RyhB is an sRNA involved in iron homeostasis in Enterobacteriaceae, while RsaA is a modulator of virulence in Staphylococcus aureus. Using such a combined strategy, a better appreciation of the sRNA‐dependent regulatory networks is now attainable.
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Affiliation(s)
- Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - David Lalaouna
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Shengwei Hou
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Steffen C Lott
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Isabelle Caldelari
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany.,Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France
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20
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Zheng J, Zheng J, Ma Y, Zuo G, Feng Y. The role of Lys2-Cl - -Lys2 salt linkages in oligomeric intermediates of RbsD protein in Escherichia coli. J Basic Microbiol 2019; 60:185-194. [PMID: 31588591 DOI: 10.1002/jobm.201900337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/07/2019] [Accepted: 09/13/2019] [Indexed: 11/06/2022]
Abstract
As a homo-oligomeric protein, the disassembly of Escherichia coli RbsD decamer produces a urea-unfolded oligomeric intermediate structure, as the dissociation speed of the protein is lower than that of the unfolding process. There are five Lys2-Cl- -Lys2 salt linkages to connect these subunits. To explore the role of the salt linkages in these oligomeric intermediates, the Lys2Ala mutated in the N-terminal of E. coli RbsD protein subunit was designed. It was found that the RbsD mutation protein (RbsD:K2A) loses its minor larger oligomers, which exist in RbsD, and displays other several oligomeric states (less than decamers), meanwhile the state of the oligomers depends on the protein concentration. It was also found that compared with RbsD, the crosslinking capability of the subunits of RbsD:K2A is weaker, while the crosslinking rate of dimers is higher, RbsD:K2A needs to substantially adjust its conformation to meet the space requirements when combined with d-ribose. On the basis of these results, we suggest that Lys2-Cl- -Lys2 salt linkages in E. coli RbsD protein play an important role in stabilizing the intermediate products of oligomers and maintaining interaction between the intermediate products of oligomers, which may shed light on the study of these oligomeric proteins.
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Affiliation(s)
- Jing Zheng
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jie Zheng
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Yuanwu Ma
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Guocai Zuo
- School of Software and Information Engineering, Hunan Software Vocational Institute, Xiangtan, China
| | - Yongjun Feng
- School of Life Science, Beijing Institute of Technology, Beijing, China
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21
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Lalaouna D, Prévost K, Laliberté G, Houé V, Massé E. Contrasting silencing mechanisms of the same target mRNA by two regulatory RNAs in Escherichia coli. Nucleic Acids Res 2019; 46:2600-2612. [PMID: 29294085 PMCID: PMC5861431 DOI: 10.1093/nar/gkx1287] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/18/2017] [Indexed: 12/21/2022] Open
Abstract
Small RNAs are key components of complex regulatory networks. These molecules can integrate multiple cellular signals to control specific target mRNAs. The recent development of high-throughput methods tremendously helped to characterize the full targetome of sRNAs. Using MS2-affinity purification coupled with RNA sequencing (MAPS) technology, we reveal the targetomes of two sRNAs, CyaR and RprA. Interestingly, both CyaR and RprA interact with the 5′-UTR of hdeD mRNA, which encodes an acid-resistance membrane protein. We demonstrate that CyaR classically binds to the RBS of hdeD, interfering with translational initiation. We identified an A/U-rich motif on hdeD, which is bound by the RNA chaperone Hfq. Our results indicate that binding of this motif by Hfq is required for CyaR-induced degradation of hdeD mRNA. Additional data suggest that two molecules of RprA must bind the 5′-UTR of hdeD to block translation initiation. Surprisingly, while both CyaR and RprA sRNAs bind to the same motif on hdeD mRNA, RprA solely acts at the translational level, leaving the target RNA intact. By interchanging the seed region of CyaR and RprA sRNAs, we also swap their regulatory behavior. These results suggest that slight changes in the seed region could modulate the regulation of target mRNAs.
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Affiliation(s)
- David Lalaouna
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Karine Prévost
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Guillaume Laliberté
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Vincent Houé
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Eric Massé
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec, Canada
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22
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The sRNA DicF integrates oxygen sensing to enhance enterohemorrhagic Escherichia coli virulence via distinctive RNA control mechanisms. Proc Natl Acad Sci U S A 2019; 116:14210-14215. [PMID: 31235565 DOI: 10.1073/pnas.1902725116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
To establish infection, enteric pathogens integrate environmental cues to navigate the gastrointestinal tract (GIT) and precisely control expression of virulence determinants. During passage through the GIT, pathogens encounter relatively high levels of oxygen in the small intestine before transit to the oxygen-limited environment of the colon. However, how bacterial pathogens sense oxygen availability and coordinate expression of virulence traits is not resolved. Here, we demonstrate that enterohemorrhagic Escherichia coli O157:H7 (EHEC) regulates virulence via the oxygen-responsive small RNA DicF. Under oxygen-limited conditions, DicF enhances global expression of the EHEC type three secretion system, which is a key virulence factor required for host colonization, through the transcriptional activator PchA. Mechanistically, the pchA coding sequence (CDS) base pairs with the 5' untranslated region of the mRNA to sequester the ribosome binding site (RBS) and inhibit translation. DicF disrupts pchA cis-interactions by binding to the pchA CDS, thereby unmasking the pchA RBS and promoting PchA expression. These findings uncover a feed-forward regulatory pathway that involves distinctive mechanisms of RNA-based regulation and that provides spatiotemporal control of EHEC virulence.
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23
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Gehrke EJ, Zhang X, Pimentel-Elardo SM, Johnson AR, Rees CA, Jones SE, Hindra, Gehrke SS, Turvey S, Boursalie S, Hill JE, Carlson EE, Nodwell JR, Elliot MA. Silencing cryptic specialized metabolism in Streptomyces by the nucleoid-associated protein Lsr2. eLife 2019; 8:47691. [PMID: 31215866 PMCID: PMC6584129 DOI: 10.7554/elife.47691] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022] Open
Abstract
Lsr2 is a nucleoid-associated protein conserved throughout the actinobacteria, including the antibiotic-producing Streptomyces. Streptomyces species encode paralogous Lsr2 proteins (Lsr2 and Lsr2-like, or LsrL), and we show here that of the two, Lsr2 has greater functional significance. We found that Lsr2 binds AT-rich sequences throughout the chromosome, and broadly represses gene expression. Strikingly, specialized metabolic clusters were over-represented amongst its targets, and the cryptic nature of many of these clusters appears to stem from Lsr2-mediated repression. Manipulating Lsr2 activity in model species and uncharacterized isolates resulted in the production of new metabolites not seen in wild type strains. Our results suggest that the transcriptional silencing of biosynthetic clusters by Lsr2 may protect Streptomyces from the inappropriate expression of specialized metabolites, and provide global control over Streptomyces’ arsenal of signaling and antagonistic compounds.
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Affiliation(s)
- Emma J Gehrke
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Xiafei Zhang
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | | | - Andrew R Johnson
- Department of Chemistry, Indiana University, Bloomington, United States
| | - Christiaan A Rees
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Stephanie E Jones
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Hindra
- Department of Biology, McMaster University, Hamilton, Canada
| | - Sebastian S Gehrke
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Sonya Turvey
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Suzanne Boursalie
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Jane E Hill
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Erin E Carlson
- Department of Chemistry, Indiana University, Bloomington, United States.,Department of Chemistry, University of Minnesota, Minneapolis, United States
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Marie A Elliot
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
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24
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Kim W, Choi JS, Kim D, Shin D, Suk S, Lee Y. Mechanisms for Hfq-Independent Activation of rpoS by DsrA, a Small RNA, in Escherichia coli. Mol Cells 2019; 42:426-439. [PMID: 31085808 PMCID: PMC6537650 DOI: 10.14348/molcells.2019.0040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023] Open
Abstract
Many small RNAs (sRNAs) regulate gene expression by base pairing to their target messenger RNAs (mRNAs) with the help of Hfq in Escherichia coli. The sRNA DsrA activates translation of the rpoS mRNA in an Hfq-dependent manner, but this activation ability was found to partially bypass Hfq when DsrA is overproduced. The precise mechanism by which DsrA bypasses Hfq is unknown. In this study, we constructed strains lacking all three rpoS-activating sRNAs (i.e., ArcZ, DsrA, and RprA) in hfq+ and Hfq- backgrounds, and then artificially regulated the cellular DsrA concentration in these strains by controlling its ectopic expression. We then examined how the expression level of rpoS was altered by a change in the concentration of DsrA. We found that the translation and stability of the rpoS mRNA are both enhanced by physiological concentrations of DsrA regardless of Hfq, but that depletion of Hfq causes a rapid degradation of DsrA and thereby decreases rpoS mRNA stability. These results suggest that the observed Hfq dependency of DsrA-mediated rpoS activation mainly results from the destabilization of DsrA in the absence of Hfq, and that DsrA itself contributes to the translational activation and stability of the rpoS mRNA in an Hfq-independent manner.
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Affiliation(s)
- Wonkyong Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Jee Soo Choi
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Daun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Doohang Shin
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Shinae Suk
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Younghoon Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
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25
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Caulobacter crescentus Hfq structure reveals a conserved mechanism of RNA annealing regulation. Proc Natl Acad Sci U S A 2019; 116:10978-10987. [PMID: 31076551 PMCID: PMC6561178 DOI: 10.1073/pnas.1814428116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In many bacteria, the RNA chaperone protein Hfq binds to hundreds of small noncoding RNAs and improves their efficacy by aiding base pairing to target mRNAs. Hfq proteins contain a variable C-terminal domain (CTD), usually structurally disordered, which was recently demonstrated to inhibit Hfq from mediating nonspecific RNA annealing. We obtained a new structure that shows how this inhibition is achieved in Caulobacter crescentus Hfq. The structural data and chaperone assays provide an initial view of the little-known mechanism of small RNA regulation in Caulobacter. In addition, this work demonstrates how the Hfq CTD has evolved to meet the needs for species-specific selectivity in RNA binding and pairing of regulatory RNAs with cognate targets. We have solved the X-ray crystal structure of the RNA chaperone protein Hfq from the alpha-proteobacterium Caulobacter crescentus to 2.15-Å resolution, resolving the conserved core of the protein and the entire C-terminal domain (CTD). The structure reveals that the CTD of neighboring hexamers pack in crystal contacts, and that the acidic residues at the C-terminal tip of the protein interact with positive residues on the rim of Hfq, as has been recently proposed for a mechanism of modulating RNA binding. De novo computational models predict a similar docking of the acidic tip residues against the core of Hfq. We also show that C. crescentus Hfq has sRNA binding and RNA annealing activities and is capable of facilitating the annealing of certain Escherichia coli sRNA:mRNA pairs in vivo. Finally, we describe how the Hfq CTD and its acidic tip residues provide a mechanism to modulate annealing activity and substrate specificity in various bacteria.
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26
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Abstract
Small regulatory RNAs are now recognized as key regulators of gene expression in bacteria. They accumulate under specific conditions, most often because their synthesis is directly controlled by transcriptional regulators, including but not limited to alternative sigma factors and response regulators of two-component systems. In turn, small RNAs regulate, mostly at the posttranscriptional level, expression of multiple genes, among which are genes encoding transcriptional regulators. Small RNAs are thus embedded in mixed regulatory circuits combining transcriptional and posttranscriptional controls, and whose properties are discussed here.
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27
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Carrier MC, Morin C, Massé E. On the Prowl: An In Vivo Method to Identify RNA Partners of a sRNA. Methods Enzymol 2018; 612:251-268. [PMID: 30502945 DOI: 10.1016/bs.mie.2018.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bacterial cells dispose of numerous strategies to regulate gene expression. Small regulatory RNAs (sRNA) are pervasive molecules that allow gene expression regulation with exquisite precision. These molecules can bind mRNAs and negatively or positively modify their stability and interfere with translation. However, many features of sRNAs render identification of new targets or RNA interacting partners increasingly complex. In this chapter, we present a detailed procedure of MAPS, an in vivo technique based on the copurification of any type of RNA bound to an MS2-tagged sRNA. By focusing on the interaction between two RNAs rather than the outcome of this interaction, MAPS has proven useful in identifying unprecedented sRNA-RNA interactions. Below, we describe how to prepare MAPS samples and how to analyze RNA sequencing data files to determine enrichment ratios of different RNAs in an experimental condition vs a control condition. MAPS can be applied to most sRNAs of Escherichia coli and Salmonella spp., and can be easily optimized to more distant bacterial species.
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Affiliation(s)
- Marie-Claude Carrier
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Claire Morin
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada.
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28
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Lalaouna D, Desgranges E, Caldelari I, Marzi S. MS2-Affinity Purification Coupled With RNA Sequencing Approach in the Human Pathogen Staphylococcus aureus. Methods Enzymol 2018; 612:393-411. [PMID: 30502950 DOI: 10.1016/bs.mie.2018.08.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Staphylococcus aureus is a Gram-positive major human pathogen involved in a wide range of human infectious diseases (from minor skin infections to septicemia, endocarditis or toxic shock syndrome). The treatment of S. aureus infections is very challenging due to the emergence of multiple antibiotic-resistant isolates. The high diversity of clinical symptoms caused by S. aureus depends on the precise expression of numerous virulence factors and stress response pathways, which are tightly regulated at every level (transcriptional, posttranscriptional, translational, and posttranslational). During the last two decades, it has become evident that small regulatory RNAs (sRNAs) play a major role in fast adaptive responses, mainly by targeting mRNA translation. sRNAs act as antisense RNAs by forming noncontiguous pairings with their target mRNAs and their mechanisms of action vary according to the interaction site. To obtain a global and detailed view of the regulatory networks involved in the adaptive processes of S. aureus, we have adapted the MAPS approach to get individual sRNA targetomes. We also set up different strategies to validate MAPS results and establish sRNA regulatory activities. As this method has been first developed in Gram-negative bacteria, we provide here a protocol for its application in S. aureus and highlight underlying differences. Finally, we discuss several points that have been and could be further improved and provide a workflow file for the automatic analysis of the sequencing in Galaxy.
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Affiliation(s)
- David Lalaouna
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC-CNRS, Strasbourg, France
| | - Emma Desgranges
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC-CNRS, Strasbourg, France
| | - Isabelle Caldelari
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC-CNRS, Strasbourg, France.
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC-CNRS, Strasbourg, France.
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29
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After the Fact(or): Posttranscriptional Gene Regulation in Enterohemorrhagic Escherichia coli O157:H7. J Bacteriol 2018; 200:JB.00228-18. [PMID: 29967119 DOI: 10.1128/jb.00228-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To adapt to ever-changing environments, pathogens quickly alter gene expression. This can occur through transcriptional, posttranscriptional, or posttranslational regulation. Historically, transcriptional regulation has been thoroughly studied to understand pathogen niche adaptation, whereas posttranscriptional and posttranslational gene regulation has only relatively recently been appreciated to play a central role in bacterial pathogenesis. Posttranscriptional regulation may involve chaperones, nucleases, and/or noncoding small RNAs (sRNAs) and typically controls gene expression by altering the stability and/or translation of the target mRNA. In this review, we highlight the global importance of posttranscriptional regulation to enterohemorrhagic Escherichia coli (EHEC) gene expression and discuss specific mechanisms of how EHEC regulates expression of virulence factors critical to host colonization and disease progression. The low infectious dose of this intestinal pathogen suggests that EHEC is particularly well adapted to respond to the host environment.
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30
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A Modular Genetic System for High-Throughput Profiling and Engineering of Multi-Target Small RNAs. Methods Mol Biol 2018. [PMID: 29484604 DOI: 10.1007/978-1-4939-7634-8_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
RNA biology and RNA engineering are subjects of growing interest due to recent advances in our understanding of the diverse cellular functions of RNAs, including their roles as genetic regulators. The noncoding small RNAs (sRNAs) of bacteria are a fundamental basis of regulatory control that can regulate gene expression via antisense base-pairing to one or more target mRNAs. The sRNAs can be customized to generate a range of mRNA translation rates and stabilities. The sRNAs can be applied as a platform for metabolic engineering, to control expression of genes of interest by following relatively straightforward design rules (Kushwaha et al., ACS Synth Biol 5:795-809, 2016). However, the ab initio design of functional sRNAs to precise specifications of gene control is not yet possible. Consequently, there is a need for tools to rapidly profile uncharacterized sRNAs in vivo, to screen sRNAs against "new/novel" targets, and (in the case of metabolic engineering) to develop engineered sRNAs for regulatory function against multiple desired mRNA targets. To address this unmet need, we previously constructed a modular genetic system for assaying sRNA activity in vivo against specifiable mRNA sequences, using microtiter plate assays for high-throughput productivity. This sRNA design platform consists of three modular plasmids: one plasmid contains an inducible sRNA and the RNA chaperone Hfq; the second contains an inducible fluorescent reporter protein and a LacY mutant transporter protein for inducer molecules; and the third plasmid contains a second inducible fluorescent reporter protein. The second reporter gene makes it possible to screen for sRNA regulators that have activity against multiple mRNAs. We describe the protocol for engineering sRNAs with novel regulatory activity using this system. This sRNA prototyping regimen could also be employed for validating predicted mRNA targets of uncharacterized, naturally occurring sRNAs or for testing hypotheses about the predicted roles of genes, including essential genes, in cellular metabolism and other processes, by using customized antisense sRNAs to knock down or tune down gene expression.
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31
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Identification of New Bacterial Small RNA Targets Using MS2 Affinity Purification Coupled to RNA Sequencing. Methods Mol Biol 2018; 1737:77-88. [PMID: 29484588 DOI: 10.1007/978-1-4939-7634-8_5] [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: 12/24/2022]
Abstract
Small regulatory RNAs (sRNAs) are ubiquitous regulatory molecules expressed in living cells. In prokaryotes, sRNAs usually bind to target mRNAs to either promote their degradation or interfere with translation initiation. Because a single sRNA can regulate a considerable number of target mRNAs, we seek to identify those targets rapidly and reliably. Here, we present a robust method based on the co-purification of target mRNAs bound to MS2-tagged sRNAs expressed in vivo. After purification of the tagged-sRNA, we use RNAseq to determine the identity of all RNA interacting partners and their enrichment level. We describe how to analyze the RNAseq data through the Galaxy Project Platform bioinformatics tools to identify new mRNA targets. This technique is applicable to most sRNAs of E. coli and Salmonella.
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32
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Leistra AN, Amador P, Buvanendiran A, Moon-Walker A, Contreras LM. Rational Modular RNA Engineering Based on In Vivo Profiling of Structural Accessibility. ACS Synth Biol 2017; 6:2228-2240. [PMID: 28796489 DOI: 10.1021/acssynbio.7b00185] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Bacterial small RNAs (sRNAs) have been established as powerful parts for controlling gene expression. However, development and application of engineered sRNAs has primarily focused on regulating novel synthetic targets. In this work, we demonstrate a rational modular RNA engineering approach that uses in vivo structural accessibility measurements to tune the regulatory activity of a multisubstrate sRNA for differential control of its native target network. Employing the CsrB global sRNA regulator as a model system, we use published in vivo structural accessibility data to infer the contribution of its local structures (substructures) to function and select a subset for engineering. We then modularly recombine the selected substructures, differentially representing those of presumed high or low functional contribution, to build a library of 21 CsrB variants. Using fluorescent translational reporter assays, we demonstrate that the CsrB variants achieve a 5-fold gradient of control of well-characterized Csr network targets. Interestingly, results suggest that less conserved local structures within long, multisubstrate sRNAs may represent better targets for rational engineering than their well-conserved counterparts. Lastly, mapping the impact of sRNA variants on a signature Csr network phenotype indicates the potential of this approach for tuning the activity of global sRNA regulators in the context of metabolic engineering applications.
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Affiliation(s)
- Abigail N. Leistra
- McKetta
Department of Chemical Engineering, University of Texas at Austin, 200
E. Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
| | - Paul Amador
- Microbiology
Graduate Program, University of Texas at Austin, 100 E. 24th Street
Stop A6500, Austin, Texas 78712, United States
| | - Aishwarya Buvanendiran
- Biological
Sciences Program College of Natural Sciences, University of Texas at Austin, 120 Inner Campus Drive Stop G2500, Austin, Texas 78712, United States
| | - Alex Moon-Walker
- Biological
Sciences Program College of Natural Sciences, University of Texas at Austin, 120 Inner Campus Drive Stop G2500, Austin, Texas 78712, United States
| | - Lydia M. Contreras
- McKetta
Department of Chemical Engineering, University of Texas at Austin, 200
E. Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
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33
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Wu P, Liu X, Yang L, Sun Y, Gong Q, Wu J, Shi Y. The important conformational plasticity of DsrA sRNA for adapting multiple target regulation. Nucleic Acids Res 2017; 45:9625-9639. [PMID: 28934467 PMCID: PMC5766208 DOI: 10.1093/nar/gkx570] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 06/22/2017] [Indexed: 01/08/2023] Open
Abstract
In bacteria, small non-coding RNAs (sRNAs) could function in gene regulations under variable stress responses. DsrA is an ∼90-nucleotide Hfq-dependent sRNA found in Escherichia coli. It regulates the translation and degradation of multiple mRNAs, such as rpoS, hns, mreB and rbsD mRNAs. However, its functional structure and particularly how it regulates multiple mRNAs remain obscure. Using NMR, we investigated the solution structures of the full-length and isolated stem-loops of DsrA. We first solved the NMR structure of the first stem-loop (SL1), and further studied the melting process of the SL1 induced by the base-pairing with the rpoS mRNA and the A-form duplex formation of the DsrA/rpoS complex. The secondary structure of the second stem-loop (SL2) was also determined, which contains a lower stem and an upper stem with distinctive stability. Interestingly, two conformational states of SL2 in dynamic equilibrium were observed in our NMR spectra, suggesting that the conformational selection may occur during the base-pairing between DsrA and mRNAs. In summary, our study suggests that the conformational plasticity of DsrA may represent a special mechanism sRNA employed to deal with its multiple regulatory targets of mRNA.
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Affiliation(s)
- Pengzhi Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Xiaodan Liu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Lingna Yang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Yitong Sun
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Jihui Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
| | - Yunyu Shi
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Anhui 230027, China
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34
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Bacterial pathogen gene regulation: a DNA-structure-centred view of a protein-dominated domain. Clin Sci (Lond) 2017; 130:1165-77. [PMID: 27252403 DOI: 10.1042/cs20160024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/15/2016] [Indexed: 02/03/2023]
Abstract
The mechanisms used by bacterial pathogens to regulate the expression of their genes, especially their virulence genes, have been the subject of intense investigation for several decades. Whole genome sequencing projects, together with more targeted studies, have identified hundreds of DNA-binding proteins that contribute to the patterns of gene expression observed during infection as well as providing important insights into the nature of the gene products whose expression is being controlled by these proteins. Themes that have emerged include the importance of horizontal gene transfer to the evolution of pathogens, the need to impose regulatory discipline upon these imported genes and the important roles played by factors normally associated with the organization of genome architecture as regulatory principles in the control of virulence gene expression. Among these architectural elements is the structure of DNA itself, its variable nature at a topological rather than just at a base-sequence level and its ability to play an active (as well as a passive) part in the gene regulation process.
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35
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Ryan D, Mukherjee M, Suar M. The expanding targetome of small RNAs in Salmonella Typhimurium. Biochimie 2017; 137:69-77. [DOI: 10.1016/j.biochi.2017.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 03/10/2017] [Indexed: 10/20/2022]
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36
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Analysis of sucrose-induced small RNAs in Streptococcus mutans in the presence of different sucrose concentrations. Appl Microbiol Biotechnol 2017; 101:5739-5748. [PMID: 28567481 DOI: 10.1007/s00253-017-8346-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/06/2017] [Accepted: 05/10/2017] [Indexed: 01/09/2023]
Abstract
Streptococcus mutans (S. mutans) is the major pathogen contributing to dental caries. Sucrose is an important carbohydrate source for S. mutans and is crucial for dental caries. Small RNAs (sRNAs) are key post-transcriptional regulators of stress adaptation and virulence in bacteria. Here, for the first time, we created three replicate RNA libraries exposed to either 1 or 5% sucrose. The expression levels of sRNAs and target genes (gtfB, gtfC, and spaP) related to virulence were assessed. In addition, some phenotypic traits were evaluated. We obtained 2125 sRNA candidates with at least 100 average reads in 1% sucrose or 5% sucrose. Of these candidates, 2 were upregulated and 20 were downregulated in 1% sucrose. Six of these 22 differentially expressed sRNAs were validated by qRT-PCR. The expression level of target gene gtfB was higher in 1% sucrose. The adherence ratio of S. mutans was higher in 1% sucrose than in 5% sucrose. The synthesis of water-insoluble glucans (WIGs) was significantly higher in 5% sucrose than in 1% sucrose. These data suggest that a series of sRNAs can be induced in response to sucrose, and that some sRNAs might be involved in the regulation of phenotypes, providing new insight into the prevention of caries.
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37
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Lahiry A, Stimple SD, Wood DW, Lease RA. Retargeting a Dual-Acting sRNA for Multiple mRNA Transcript Regulation. ACS Synth Biol 2017; 6:648-658. [PMID: 28067500 DOI: 10.1021/acssynbio.6b00261] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Multitargeting small regulatory RNAs (sRNAs) represent a potentially useful tool for metabolic engineering applications. Natural multitargeting sRNAs govern bacterial gene expression by binding to the translation initiation regions of protein-coding mRNAs through base pairing. We designed an Escherichia coli based genetic system to create and assay dual-acting retargeted-sRNA variants. The variants can be assayed for coordinate translational regulation of two alternate mRNA leaders fused to independent reporter genes. Accordingly, we began with the well-characterized E. coli native DsrA sRNA. The merits of using DsrA include its well-characterized separation of function into two independently folded stem-loop domains, wherein alterations at one stem do not necessarily abolish activity at the other stem. Expression of the sRNA and each reporter mRNA was independently controlled by small inducer molecules, allowing precise quantification of the regulatory effects of each sRNA:mRNA interaction in vivo with a microtiter plate assay. Using this system, we semirationally designed DsrA variants screened in E. coli for their ability to regulate key mRNA leader sequences from the Clostridium acetobutylicum n-butanol synthesis pathway. To coordinate intervention at two points in a metabolic pathway, we created bifunctional sRNA prototypes by combining sequences from two singly retargeted DsrA variants. This approach constitutes a platform for designing sRNAs to specifically target arbitrary mRNA transcript sequences, and thus provides a generalizable tool for retargeting and characterizing multitarget sRNAs for metabolic engineering.
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Affiliation(s)
- Ashwin Lahiry
- Department
of Microbiology, The Ohio State University, 484 W. 12th Avenue, Columbus, Ohio 43210, United States
| | - Samuel D. Stimple
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
| | - David W. Wood
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
- Department
of Microbiology, The Ohio State University, 484 W. 12th Avenue, Columbus, Ohio 43210, United States
| | - Richard A. Lease
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
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38
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Lalaouna D, Prévost K, Eyraud A, Massé E. Identification of unknown RNA partners using MAPS. Methods 2016; 117:28-34. [PMID: 27876680 DOI: 10.1016/j.ymeth.2016.11.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/05/2016] [Accepted: 11/17/2016] [Indexed: 01/02/2023] Open
Abstract
Recent advances in high-throughput sequencing have led to an explosion in the rate of small regulatory RNAs (sRNAs) discovery among bacteria. However, only a handful of them are functionally characterized. Most of the time, little to no targets are known. In Lalaouna et al. (2015), we proposed a new technology to uncover sRNAs targetome, which is based on the MS2-affinity purification (MAPS). We were able to prove its efficiency by applying it on well-characterized sRNAs of Escherichia coli. Thereafter, we adapted the procedure to other kind of RNA (mRNAs and tRNA-derived RNA fragments) and bacteria (pathogenic or Gram-positive strains). Here, we clearly report all improvements and adjustments made to MAPS technology since it was originally reported.
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Affiliation(s)
- David Lalaouna
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Karine Prévost
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Alex Eyraud
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Eric Massé
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada.
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39
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Fan Y, Evans CR, Ling J. Reduced Protein Synthesis Fidelity Inhibits Flagellar Biosynthesis and Motility. Sci Rep 2016; 6:30960. [PMID: 27468805 PMCID: PMC4965754 DOI: 10.1038/srep30960] [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: 05/18/2016] [Accepted: 07/12/2016] [Indexed: 01/02/2023] Open
Abstract
Accurate translation of the genetic information from DNA to protein is maintained by multiple quality control steps from bacteria to mammals. Genetic and environmental alterations have been shown to compromise translational quality control and reduce fidelity during protein synthesis. The physiological impact of increased translational errors is not fully understood. While generally considered harmful, translational errors have recently been shown to benefit cells under certain stress conditions. In this work, we describe a novel regulatory pathway in which reduced translational fidelity downregulates expression of flagellar genes and suppresses bacterial motility. Electron microscopy imaging shows that the error-prone Escherichia coli strain lacks mature flagella. Further genetic analyses reveal that translational errors upregulate expression of a small RNA DsrA through enhancing its transcription, and deleting DsrA from the error-prone strain restores motility. DsrA regulates expression of H-NS and RpoS, both of which regulate flagellar genes. We demonstrate that an increased level of DsrA in the error-prone strain suppresses motility through the H-NS pathway. Our work suggests that bacteria are capable of switching on and off the flagellar system by altering translational fidelity, which may serve as a previously unknown mechanism to improve fitness in response to environmental cues.
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Affiliation(s)
- Yongqiang Fan
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Christopher R Evans
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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40
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Abstract
In the last few decades, small regulatory RNA (sRNA) molecules emerged as key regulators in every kingdom of life. Resolving the full targetome of sRNAs has however remained a challenge. To address this, we used an in vivo tagging MS2-affinity purification protocol coupled with RNA sequencing technology, namely MAPS, to assemble full bacterial small RNAs targetomes. The impressive potential of MAPS has been supported by a number of reports. Here, we concisely overview RNA-tagging history that preceded the development of the MAPS assay and expose the range of possible uses of this technology.
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Affiliation(s)
- Marie-Claude Carrier
- a Department of Biochemistry , RNA Group, Université de Sherbrooke , Sherbrooke, Québec , Canada
| | - David Lalaouna
- a Department of Biochemistry , RNA Group, Université de Sherbrooke , Sherbrooke, Québec , Canada
| | - Eric Massé
- a Department of Biochemistry , RNA Group, Université de Sherbrooke , Sherbrooke, Québec , Canada
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Lalaouna D, Massé E. The spectrum of activity of the small RNA DsrA: not so narrow after all. Curr Genet 2015; 62:261-4. [PMID: 26607444 DOI: 10.1007/s00294-015-0533-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/27/2015] [Accepted: 10/28/2015] [Indexed: 11/28/2022]
Abstract
For a long time, the small regulatory RNA DsrA has been considered as a regulator with a narrow spectrum of action due to its restricted targetome. Since the first reports on DsrA characterization, only two targets of DsrA have been described: rpoS and hns mRNAs, encoding the sigma factor σS and the nucleoid-associated protein H-NS, respectively. Recently, the scope of DsrA targetome has been expanded by the characterization of two negatively regulated mRNAs, mreB and rbsD, involved in cell wall biosynthesis and ribose metabolism, respectively. In this review, we summarize new insights in DsrA-mediated regulation and emphasize the versatility of DsrA modes of action.
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Affiliation(s)
- David Lalaouna
- RNA Group, Department of Biochemistry, Université de Sherbrooke, 3201 Jean Mignault Street, Sherbrooke, QC, J1E 4K8, Canada
| | - Eric Massé
- RNA Group, Department of Biochemistry, Université de Sherbrooke, 3201 Jean Mignault Street, Sherbrooke, QC, J1E 4K8, Canada.
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