1
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Ganske A, Busch LM, Hentschker C, Reder A, Michalik S, Surmann K, Völker U, Mäder U. Exploring the targetome of IsrR, an iron-regulated sRNA controlling the synthesis of iron-containing proteins in Staphylococcus aureus. Front Microbiol 2024; 15:1439352. [PMID: 39035440 PMCID: PMC11257911 DOI: 10.3389/fmicb.2024.1439352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 06/25/2024] [Indexed: 07/23/2024] Open
Abstract
Staphylococcus aureus is a common colonizer of the skin and nares of healthy individuals, but also a major cause of severe human infections. During interaction with the host, pathogenic bacteria must adapt to a variety of adverse conditions including nutrient deprivation. In particular, they encounter severe iron limitation in the mammalian host through iron sequestration by haptoglobin and iron-binding proteins, a phenomenon called "nutritional immunity." In most bacteria, including S. aureus, the ferric uptake regulator (Fur) is the key regulator of iron homeostasis, which primarily acts as a transcriptional repressor of genes encoding iron acquisition systems. Moreover, Fur can control the expression of trans-acting small regulatory RNAs that play an important role in the cellular iron-sparing response involving major changes in cellular metabolism under iron-limiting conditions. In S. aureus, the sRNA IsrR is controlled by Fur, and most of its predicted targets are iron-containing proteins and other proteins related to iron metabolism and iron-dependent pathways. To characterize the IsrR targetome on a genome-wide scale, we combined proteomics-based identification of potential IsrR targets using S. aureus strains either lacking or constitutively expressing IsrR with an in silico target prediction approach, thereby suggesting 21 IsrR targets, of which 19 were negatively affected by IsrR based on the observed protein patterns. These included several Fe-S cluster- and heme-containing proteins, such as TCA cycle enzymes and catalase encoded by katA. IsrR affects multiple metabolic pathways connected to the TCA cycle as well as the oxidative stress response of S. aureus and links the iron limitation response to metabolic remodeling. In contrast to the majority of target mRNAs, the IsrR-katA mRNA interaction is predicted upstream of the ribosome binding site, and further experiments including mRNA half-life measurements demonstrated that IsrR, in addition to inhibiting translation initiation, can downregulate target protein levels by affecting mRNA stability.
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Affiliation(s)
| | | | | | | | | | | | | | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
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2
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Loiseau L, Vergnes A, Ezraty B. Methionine oxidation under anaerobic conditions in Escherichia coli. Mol Microbiol 2022; 118:387-402. [PMID: 36271735 DOI: 10.1111/mmi.14971] [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: 05/08/2022] [Revised: 07/18/2022] [Accepted: 08/04/2022] [Indexed: 01/07/2023]
Abstract
Repairing oxidative-targeted macromolecules is a central mechanism necessary for living organisms to adapt to oxidative stress. Reactive oxygen and chlorine species preferentially oxidize sulfur-containing amino acids in proteins. Among these amino acids, methionine can be converted into methionine sulfoxide. This post-translational oxidation can be reversed by methionine sulfoxide reductases, Msr enzymes. In Gram-negative bacteria, the antioxidant MsrPQ system is involved in the repair of periplasmic oxidized proteins. Surprisingly, in this study, we observed in Escherichia coli that msrPQ was highly expressed in the absence of oxygen. We have demonstrated that the anaerobic induction of msrPQ was due to chlorate (ClO3 - ) contamination of the Casamino Acids. Molecular investigation led us to determine that the reduction of chlorate to the toxic oxidizing agent chlorite (ClO2 - ) by the three nitrate reductases (NarA, NarZ, and Nap) led to methionine oxidation of periplasmic proteins. In response to this stress, the E. coli HprSR two-component system was activated, leading to the over-production of MsrPQ. This study, therefore, supports the idea that methionine oxidation in proteins is part of chlorate toxicity, and that MsrPQ can be considered as an anti-chlorate/chlorite defense system in bacteria. Finally, this study challenges the traditional view of the absence of Met-oxidation during anaerobiosis.
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Affiliation(s)
- Laurent Loiseau
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille University, CNRS, Marseille, France
| | - Alexandra Vergnes
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille University, CNRS, Marseille, France
| | - Benjamin Ezraty
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille University, CNRS, Marseille, France
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3
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Jha T, Mendel J, Cho H, Choudhary M. Prediction of Bacterial sRNAs Using Sequence-Derived Features and Machine Learning. Bioinform Biol Insights 2022; 16:11779322221118335. [PMID: 36016866 PMCID: PMC9397377 DOI: 10.1177/11779322221118335] [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: 03/23/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022] Open
Abstract
Small ribonucleic acid (sRNA) sequences are 50–500 nucleotide long, noncoding RNA (ncRNA) sequences that play an important role in regulating transcription and translation within a bacterial cell. As such, identifying sRNA sequences within an organism’s genome is essential to understand the impact of the RNA molecules on cellular processes. Recently, numerous machine learning models have been applied to predict sRNAs within bacterial genomes. In this study, we considered the sRNA prediction as an imbalanced binary classification problem to distinguish minor positive sRNAs from major negative ones within imbalanced data and then performed a comparative study with six learning algorithms and seven assessment metrics. First, we collected numerical feature groups extracted from known sRNAs previously identified in Salmonella typhimurium LT2 (SLT2) and Escherichia coli K12 (E. coli K12) genomes. Second, as a preliminary study, we characterized the sRNA-size distribution with the conformity test for Benford’s law. Third, we applied six traditional classification algorithms to sRNA features and assessed classification performance with seven metrics, varying positive-to-negative instance ratios, and utilizing stratified 10-fold cross-validation. We revisited important individual features and feature groups and found that classification with combined features perform better than with either an individual feature or a single feature group in terms of Area Under Precision-Recall curve (AUPR). We reconfirmed that AUPR properly measures classification performance on imbalanced data with varying imbalance ratios, which is consistent with previous studies on classification metrics for imbalanced data. Overall, eXtreme Gradient Boosting (XGBoost), even without exploiting optimal hyperparameter values, performed better than the other five algorithms with specific optimal parameter settings. As a future work, we plan to extend XGBoost further to a large amount of published sRNAs in bacterial genomes and compare its classification performance with recent machine learning models’ performance.
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Affiliation(s)
- Tony Jha
- Department of Mathematics, University of California, Berkeley, Berkeley, CA, USA
| | - Jovinna Mendel
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Hyuk Cho
- Department of Computer Science, Sam Houston State University, Huntsville, TX, USA
| | - Madhusudan Choudhary
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
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4
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Nakashima Y, Shiiyama N, Urabe T, Yamashita H, Yasuda S, Igoshi K, Kinoshita H. Functions of small RNAs in Lactobacillus casei-Pediococcus group of lactic acid bacteria using fragment analysis. FEMS Microbiol Lett 2021; 367:5928547. [PMID: 33068404 DOI: 10.1093/femsle/fnaa154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Small RNAs (sRNA) are non-cording RNAs composed of 50∼400 nt responsible for coordinating the adaption of Escherichia coli and other bacteria to changing environmental conditions, including pH and temperature. However, the role of sRNAs in lactic acid bacteria (LAB) has not yet been clarified. In this study, we used the Lactobacillus casei-Pediococcus group to evaluate the function of sRNAs in LAB, using RNA sequencing in the exponential growth phase and stationary phase to map and analyze sRNA fragments, which were categorized as Pediococcus pentosaceus and Lactobacillus paracasei. We evaluated the role of sRNAs in nutrient synthesis for cell growth in exponential growth phase and in protein and biofilm biosynthesis for cell body durability. During exponential growth, the sRNA fragments were found to be involved in the stress response in Pediococcus pentosaceus and in environmental adaption in Lactobacillus paracasei. The results suggest that the function of sRNA can be characterized from sRNA fragments using RNA sequencing during the exponential growth and stationary phases in Lactobacillus casei-Pediococcus group.
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Affiliation(s)
- Yuki Nakashima
- Graduate School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Narumi Shiiyama
- Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Taihei Urabe
- Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Hideji Yamashita
- Graduate School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan.,Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Shin Yasuda
- Graduate School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan.,Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Keiji Igoshi
- Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
| | - Hideki Kinoshita
- Graduate School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan.,Department of Bioscience, School of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto-shi, Kumamoto, Japan
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5
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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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6
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Kappler U, Nasreen M, McEwan A. New insights into the molecular physiology of sulfoxide reduction in bacteria. Adv Microb Physiol 2019; 75:1-51. [PMID: 31655735 DOI: 10.1016/bs.ampbs.2019.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Sulfoxides occur in biology as products of the S-oxygenation of small molecules as well as in peptides and proteins and their formation is often associated with oxidative stress and can affect biological function. In bacteria, sulfoxide damage can be reversed by different types of enzymes. Thioredoxin-dependent peptide methionine sulfoxide reductases (MSR proteins) repair oxidized methionine residues and are found in all Domains of life. In bacteria MSR proteins are often found in the cytoplasm but in some bacteria, including pathogenic Neisseria, Streptococci, and Haemophilus they are extracytoplasmic. Mutants lacking MSR proteins are often sensitive to oxidative stress and in pathogens exhibit decreased virulence as indicated by reduced survival in host cell or animal model systems. Molybdenum enzymes are also known to reduce S-oxides and traditionally their physiological role was considered to be in anaerobic respiration using dimethylsulfoxide (DMSO) as an electron acceptor. However, it now appears that some enzymes (MtsZ) of the DMSO reductase family of Mo enzymes use methionine sulfoxide as preferred physiological substrate and thus may be involved in scavenging/recycling of this amino acid. Similarly, an enzyme (MsrP/YedY) of the sulfite oxidase family of Mo enzymes has been shown to be involved in repair of methionine sulfoxides in periplasmic proteins. Again, some mutants deficient in Mo-dependent sulfoxide reductases exhibit reduced virulence, and there is evidence that these Mo enzymes and some MSR systems are induced by hypochlorite produced by the innate immune system. This review describes recent advances in the understanding of the molecular microbiology of MSR systems and the broadening of the role of Mo-dependent sulfoxide reductase to encompass functions beyond anaerobic respiration.
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Affiliation(s)
- Ulrike Kappler
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Marufa Nasreen
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Alastair McEwan
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
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7
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Mann M, Wright PR, Backofen R. IntaRNA 2.0: enhanced and customizable prediction of RNA-RNA interactions. Nucleic Acids Res 2019; 45:W435-W439. [PMID: 28472523 PMCID: PMC5570192 DOI: 10.1093/nar/gkx279] [Citation(s) in RCA: 398] [Impact Index Per Article: 79.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/02/2017] [Indexed: 01/01/2023] Open
Abstract
The IntaRNA algorithm enables fast and accurate prediction of RNA-RNA hybrids by incorporating seed constraints and interaction site accessibility. Here, we introduce IntaRNAv2, which enables enhanced parameterization as well as fully customizable control over the prediction modes and output formats. Based on up to date benchmark data, the enhanced predictive quality is shown and further improvements due to more restrictive seed constraints are highlighted. The extended web interface provides visualizations of the new minimal energy profiles for RNA-RNA interactions. These allow a detailed investigation of interaction alternatives and can reveal potential interaction site multiplicity. IntaRNAv2 is freely available (source and binary), and distributed via the conda package manager. Furthermore, it has been included into the Galaxy workflow framework and its already established web interface enables ad hoc usage.
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Affiliation(s)
- Martin Mann
- Bioinformatics, Computer Science, University of Freiburg, Georges-Koehler-Allee 106, 79110 Freiburg, Germany
| | - Patrick R Wright
- Bioinformatics, Computer Science, University of Freiburg, Georges-Koehler-Allee 106, 79110 Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics, Computer Science, University of Freiburg, Georges-Koehler-Allee 106, 79110 Freiburg, Germany.,Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Schaenzlestr. 18, 79104 Freiburg, Germany
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8
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Makukhin N, Havelka V, Poláchová E, Rampírová P, Tarallo V, Strisovsky K, Míšek J. Resolving oxidative damage to methionine by an unexpected membrane-associated stereoselective reductase discovered using chiral fluorescent probes. FEBS J 2019; 286:4024-4035. [PMID: 31166082 DOI: 10.1111/febs.14951] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/24/2019] [Accepted: 06/04/2019] [Indexed: 10/26/2022]
Abstract
Nonenzymatic oxidative processes in living organisms are among the inevitable consequences of respiration and environmental conditions. These oxidative processes can lead to the formation of two stereoisomers (R and S) of methionine sulfoxide, and the redox balance between methionine and methionine sulfoxide in proteins has profound implications on their function. Methionine oxidation can be reverted enzymatically by methionine sulfoxide reductases (Msrs). The two enzyme classes known to fulfill this role are MsrA, reducing the (S)-isomer, and MsrB, reducing the (R)-isomer of methionine sulfoxide. They are strictly stereoselective and conserved throughout the tree of life. Under stress conditions such as stationary phase and nutrient starvation, Escherichia coli upregulates the expression of MsrA but a similar effect has not been described for MsrB, raising the conundrum of which pathway enables reduction of the (R)-isomer of methionine sulfoxide in these conditions. Using the recently developed chiral fluorescent probes Sulfox-1, we show that in stationary phase-stressed E. coli, MsrA does have a stereocomplementary activity reducing the (R)-isomer of methionine sulfoxide. However, this activity is not provided by MsrB as expected, but instead by the DMSO reductase complex DmsABC, widely conserved in bacteria. This finding reveals an unexpected diversity in the metabolic enzymes of redox regulation concerning methionine, which should be taken into account in any antibacterial strategies exploiting oxidative stress. DATABASE: The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD013610.
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Affiliation(s)
- Nikolai Makukhin
- Department of Organic Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Václav Havelka
- Department of Organic Chemistry, Faculty of Science, Charles University, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Edita Poláchová
- First Faculty of Medicine, Charles University, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Petra Rampírová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Vincenzo Tarallo
- Department of Organic Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Kvido Strisovsky
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Prague, Czech Republic
| | - Jiří Míšek
- Department of Organic Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
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9
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sRNA Target Prediction Organizing Tool (SPOT) Integrates Computational and Experimental Data To Facilitate Functional Characterization of Bacterial Small RNAs. mSphere 2019; 4:4/1/e00561-18. [PMID: 30700509 PMCID: PMC6354806 DOI: 10.1128/msphere.00561-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Small RNAs (sRNAs) regulate gene expression in diverse bacteria by interacting with mRNAs to change their structure, stability, or translation. Hundreds of sRNAs have been identified in bacteria, but characterization of their regulatory functions is limited by difficulty with sensitive and accurate identification of mRNA targets. Thus, new robust methods of bacterial sRNA target identification are in demand. Here, we describe our small RNA target prediction organizing tool (SPOT), which streamlines the process of sRNA target prediction by providing a single pipeline that combines available computational prediction tools with customizable results filtering based on experimental data. SPOT allows the user to rapidly produce a prioritized list of predicted sRNA-target mRNA interactions that serves as a basis for further experimental characterization. This tool will facilitate elucidation of sRNA regulons in bacteria, allowing new discoveries regarding the roles of sRNAs in bacterial stress responses and metabolic regulation. Small RNAs (sRNAs) posttranscriptionally regulate mRNA targets, typically under conditions of environmental stress. Although hundreds of sRNAs have been discovered in diverse bacterial genomes, most sRNAs remain uncharacterized, even in model organisms. Identification of mRNA targets directly regulated by sRNAs is rate-limiting for sRNA functional characterization. To address this, we developed a computational pipeline that we named SPOT for sRNA target prediction organizing tool. SPOT incorporates existing computational tools to search for sRNA binding sites, allows filtering based on experimental data, and organizes the results into a standardized report. SPOT sensitivity (number of correctly predicted targets/number of total known targets) was equal to or exceeded any individual method when used on 12 characterized sRNAs. Using SPOT, we generated a set of target predictions for the sRNA RydC, which was previously shown to positively regulate cfa mRNA, encoding cyclopropane fatty acid synthase. SPOT identified cfa along with additional putative mRNA targets, which we then tested experimentally. Our results demonstrated that in addition to cfa mRNA, RydC also regulates trpE and pheA mRNAs, which encode aromatic amino acid biosynthesis enzymes. Our results suggest that SPOT can facilitate elucidation of sRNA target regulons to expand our understanding of the many regulatory roles played by bacterial sRNAs. IMPORTANCE Small RNAs (sRNAs) regulate gene expression in diverse bacteria by interacting with mRNAs to change their structure, stability, or translation. Hundreds of sRNAs have been identified in bacteria, but characterization of their regulatory functions is limited by difficulty with sensitive and accurate identification of mRNA targets. Thus, new robust methods of bacterial sRNA target identification are in demand. Here, we describe our small RNA target prediction organizing tool (SPOT), which streamlines the process of sRNA target prediction by providing a single pipeline that combines available computational prediction tools with customizable results filtering based on experimental data. SPOT allows the user to rapidly produce a prioritized list of predicted sRNA-target mRNA interactions that serves as a basis for further experimental characterization. This tool will facilitate elucidation of sRNA regulons in bacteria, allowing new discoveries regarding the roles of sRNAs in bacterial stress responses and metabolic regulation.
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10
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Genetic regulation of longevity and age-associated diseases through the methionine sulfoxide reductase system. Biochim Biophys Acta Mol Basis Dis 2018; 1865:1756-1762. [PMID: 30481589 DOI: 10.1016/j.bbadis.2018.11.016] [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] [Received: 05/31/2018] [Revised: 09/25/2018] [Accepted: 11/14/2018] [Indexed: 12/13/2022]
Abstract
Methionine sulfoxide reductase enzymes are a protective system against biological oxidative stress in aerobic organisms. Modifications to this antioxidant system have been shown to impact the lifespan of several model system organisms. In humans, methionine oxidation of critical proteins and deficiencies in the methionine sulfoxide reductase system have been linked to age-related diseases, including cancer and neurodegenerative disease. Substrates for methionine sulfoxide reductases have been reviewed multiple times, and are still an active area of discovery. In contrast, less is known about the genetic regulation of methionine sulfoxide reductases. In this review, we discuss studies on the genetic regulation of the methionine sulfoxide reductase system with relevance to longevity and age-related diseases. A better understanding of genetic regulation for methionine sulfoxide reductases may lead to new therapeutic approaches for age-related diseases in the future.
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11
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Singh VK, Singh K, Baum K. The Role of Methionine Sulfoxide Reductases in Oxidative Stress Tolerance and Virulence of Staphylococcus aureus and Other Bacteria. Antioxidants (Basel) 2018; 7:antiox7100128. [PMID: 30274148 PMCID: PMC6210949 DOI: 10.3390/antiox7100128] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/19/2018] [Accepted: 09/26/2018] [Indexed: 11/18/2022] Open
Abstract
Methionine sulfoxide reductases (MSRA1 and MSRB) are proteins overproduced in Staphylococcus aureus during exposure with cell wall-active antibiotics. Later studies identified the presence of two additional MSRA proteins (MSRA2 and MSRA3) in S. aureus. These MSR proteins have been characterized in many other bacteria as well. This review provides the current knowledge about the conditions and regulatory network that mimic the expression of these MSR encoding genes and their role in defense from oxidative stress and virulence.
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Affiliation(s)
- Vineet K Singh
- Department of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA.
| | | | - Kyle Baum
- Department of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA.
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12
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Abstract
ABSTRACT
While iron is essential to sustain growth, its excess can be detrimental to the cell by generating highly toxic reactive oxygen species. Regulation of iron homeostasis thus plays a vital role in almost all living organisms. During the last 15 years, the small RNA (sRNA) RyhB has been shown to be a key actor of iron homeostasis regulation in bacteria. Through multiple molecular mechanisms, RyhB represses expendable iron-utilizing proteins, promotes siderophore production, and coordinates Fe-S cluster cofactor biogenesis, thereby establishing a so-called iron-sparing response. In this review, we will summarize knowledge on how sRNAs control iron homeostasis mainly through studies on RyhB in
Escherichia coli
. The parallel roles and modes of action of other sRNAs in different bacteria will also be described. Finally, we will discuss what questions remain to be answered concerning this important stress response regulation by sRNAs.
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13
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Small RNA-mediated regulation in bacteria: A growing palette of diverse mechanisms. Gene 2018; 656:60-72. [PMID: 29501814 DOI: 10.1016/j.gene.2018.02.068] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/19/2018] [Accepted: 02/27/2018] [Indexed: 11/23/2022]
Abstract
Small RNAs (sRNAs) in bacteria have evolved with diverse mechanisms to balance their target gene expression in response to changes in the environment. Accumulating studies on bacterial regulatory processes firmly established that sRNAs modulate their target gene expression generally at the posttranscriptional level. Identification of large number of sRNAs by advanced technologies, like deep sequencing, tilling microarray, indicates the existence of a plethora of distinctive sRNA-mediated regulatory mechanisms in bacteria. Types of the novel mechanisms are increasing with the discovery of new sRNAs. Complementary base pairing between sRNAs and target RNAs assisted by RNA chaperones like Hfq and ProQ, in many occasions, to regulate the cognate gene expression is prevalent in sRNA mechanisms. sRNAs, in most studied cases, can directly base pair with target mRNA to remodel its expression. Base pairing can happen either in the untranslated regions or in the coding regions of mRNA to activate/repress its translation. sRNAs also act as target mimic to titrate away different regulatory RNAs from its target. Other mechanism includes the sequestration of regulatory proteins, especially transcription factors, by sRNAs. Numerous sRNAs, following analogous mechanism, are widespread in bacteria, and thus, has drawn immense attention for the development of RNA-based technologies. Nevertheless, typical sRNA mechanisms are also discovered to be confined in some bacteria. Analysis of the sRNA mechanisms unravels their existence in both the single step processes and the complex regulatory networks with a global effect on cell physiology. This review deals with the diverse array of mechanisms, which sRNAs follow to maintain bacterial lifestyle.
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14
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Falcone M, Ferrara S, Rossi E, Johansen HK, Molin S, Bertoni G. The Small RNA ErsA of Pseudomonas aeruginosa Contributes to Biofilm Development and Motility through Post-transcriptional Modulation of AmrZ. Front Microbiol 2018; 9:238. [PMID: 29497413 PMCID: PMC5819304 DOI: 10.3389/fmicb.2018.00238] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/31/2018] [Indexed: 11/13/2022] Open
Abstract
The small RNA ErsA of Pseudomonas aeruginosa was previously suggested to be involved in biofilm formation via negative post-transcriptional regulation of the algC gene that encodes the virulence-associated enzyme AlgC, which provides sugar precursors for the synthesis of several polysaccharides. In this study, we show that a knock-out ersA mutant strain forms a flat and uniform biofilm, not characterized by mushroom-multicellular structures typical of a mature biofilm. Conversely, the knock-out mutant strain showed enhanced swarming and twitching motilities. To assess the influence of ErsA on the P. aeruginosa transcriptome, we performed RNA-seq experiments comparing the knock-out mutant with the wild-type. More than 160 genes were found differentially expressed in the knock-out mutant. Parts of these genes, important for biofilm formation and motility regulation, are known to belong also to the AmrZ transcriptional regulator regulon. Here, we show that ErsA binds in vitro and positively regulates amrZ mRNA at post-transcriptional level in vivo suggesting an interesting contribution of the ErsA-amrZ mRNA interaction in biofilm development at several regulatory levels.
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Affiliation(s)
- Marilena Falcone
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Silvia Ferrara
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Elio Rossi
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Helle K Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Giovanni Bertoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
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15
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Lee HJ, Gottesman S. sRNA roles in regulating transcriptional regulators: Lrp and SoxS regulation by sRNAs. Nucleic Acids Res 2016; 44:6907-23. [PMID: 27137887 PMCID: PMC5001588 DOI: 10.1093/nar/gkw358] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/21/2016] [Indexed: 11/13/2022] Open
Abstract
Post-transcriptional regulation of transcription factors contributes to regulatory circuits. We created translational reporter fusions for multiple central regulators in Escherichia coli and examined the effect of Hfq-dependent non-coding RNAs on these fusions. This approach yields an 'RNA landscape,' identifying Hfq-dependent sRNAs that regulate a given fusion. No significant sRNA regulation of crp or fnr was detected. hns was regulated only by DsrA, as previously reported. Lrp and SoxS were both found to be regulated post-transcriptionally. Lrp, ' L: eucine-responsive R: egulatory P: rotein,' regulates genes involved in amino acid biosynthesis and catabolism and other cellular functions. sRNAs DsrA, MicF and GcvB each independently downregulate the lrp translational fusion, confirming previous reports for MicF and GcvB. MicF and DsrA interact with an overlapping site early in the lrp ORF, while GcvB acts upstream at two independent sites in the long lrp leader. Surprisingly, GcvB was found to be responsible for significant downregulation of lrp after oxidative stress; MicF also contributed. SoxS, an activator of genes used to combat oxidative stress, is negatively regulated by sRNA MgrR. This study demonstrates that while not all global regulators are subject to sRNA regulation, post-transcriptional control by sRNAs allows multiple environmental signals to affect synthesis of the transcriptional regulator.
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Affiliation(s)
- Hyun-Jung Lee
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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16
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Kim JN. Roles of two RyhB paralogs in the physiology of Salmonella enterica. Microbiol Res 2016; 186-187:146-52. [PMID: 27242152 DOI: 10.1016/j.micres.2016.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/07/2016] [Accepted: 04/10/2016] [Indexed: 11/18/2022]
Abstract
Salmonella has evolved complicated regulatory systems to regulate the expression of virulence determinants that are acquired by horizontal gene transfer in response to various environmental niches. Among these, small RNA (sRNA)-mediated regulation exhibits unique features, distinct from those of protein factor-mediated regulation, which may provide benefits for a pathogen coping with the complex stress conditions encountered during host infection. Specifically, iron acquisition by this pathogenic bacterium is important for cellular processes such as energy metabolism and DNA replication. Many studies on the role of RyhB sRNA have begun to unveil the essential nature of iron acquisition in allowing the organism to persist and develop pathogenicity. The Salmonella genome encodes two RyhB paralogs, RyhB-1 and RyhB-2, which are known to act singularly or together on target expression. Based on the mechanism of Escherichia coli RyhB function, this review proposes a possible model to show how two Salmonella RyhB paralogs regulate the level of target mRNAs by sensing environmental inputs or conditions. This review also describes the involvement of Salmonella RyhBs in diverse functions including nitrate homeostasis, adaptive system to oxidative stress, and intracellular survival. Thus, the two Salmonella RyhBs play a critical role in the regulation of gene expression that appears to be essential for persistence and pathogenesis of Salmonella spp.
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Affiliation(s)
- Jeong Nam Kim
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, United States.
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17
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Regulation of Expression of Oxacillin-Inducible Methionine Sulfoxide Reductases in Staphylococcus aureus. Int J Microbiol 2015; 2015:617925. [PMID: 26483841 PMCID: PMC4592908 DOI: 10.1155/2015/617925] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/26/2015] [Accepted: 09/02/2015] [Indexed: 11/29/2022] Open
Abstract
Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) in Staphylococcus aureus. To understand the regulation of this locus, reporter strains were constructed by integrating a DNA fragment consisting of the msrA1/msrB promoter in front of a promoterless lacZ gene in the chromosome of wild-type and MsrA1-, MsrB-, MsrA1/MsrB-, and SigB-deficient methicillin-sensitive S. aureus strain SH1000 and methicillin-resistant S. aureus strain COL. These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000. In S. aureus strain COL, the highest level of β-galactosidase activity was observed under the conditions when both MsrA1 and MsrB proteins were absent. The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.
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18
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Becker KW, Skaar EP. Metal limitation and toxicity at the interface between host and pathogen. FEMS Microbiol Rev 2014; 38:1235-49. [PMID: 25211180 DOI: 10.1111/1574-6976.12087] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 08/09/2014] [Accepted: 08/31/2014] [Indexed: 12/14/2022] Open
Abstract
Metals are required cofactors for numerous fundamental processes that are essential to both pathogen and host. They are coordinated in enzymes responsible for DNA replication and transcription, relief from oxidative stress, and cellular respiration. However, excess transition metals can be toxic due to their ability to cause spontaneous, redox cycling and disrupt normal metabolic processes. Vertebrates have evolved intricate mechanisms to limit the availability of some crucial metals while concurrently flooding sites of infection with antimicrobial concentrations of other metals. To compete for limited metal within the host while simultaneously preventing metal toxicity, pathogens have developed a series of metal regulatory, acquisition, and efflux systems. This review will cover the mechanisms by which pathogenic bacteria recognize and respond to host-induced metal scarcity and toxicity.
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Affiliation(s)
- Kyle W Becker
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
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Drazic A, Winter J. The physiological role of reversible methionine oxidation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1367-82. [PMID: 24418392 DOI: 10.1016/j.bbapap.2014.01.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/17/2013] [Accepted: 01/02/2014] [Indexed: 01/04/2023]
Abstract
Sulfur-containing amino acids such as cysteine and methionine are particularly vulnerable to oxidation. Oxidation of cysteine and methionine in their free amino acid form renders them unavailable for metabolic processes while their oxidation in the protein-bound state is a common post-translational modification in all organisms and usually alters the function of the protein. In the majority of cases, oxidation causes inactivation of proteins. Yet, an increasing number of examples have been described where reversible cysteine oxidation is part of a sophisticated mechanism to control protein function based on the redox state of the protein. While for methionine the dogma is still that its oxidation inhibits protein function, reversible methionine oxidation is now being recognized as a powerful means of triggering protein activity. This mode of regulation involves oxidation of methionine to methionine sulfoxide leading to activated protein function, and inactivation is accomplished by reduction of methionine sulfoxide back to methionine catalyzed by methionine sulfoxide reductases. Given the similarity to thiol-based redox-regulation of protein function, methionine oxidation is now established as a novel mode of redox-regulation of protein function. This article is part of a Special Issue entitled: Thiol-Based Redox Processes.
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Affiliation(s)
- Adrian Drazic
- Center for Integrated Protein Science Munich (CiPS(M)) at the Department Chemie, Technische Universität München, 85747 Garching, Germany
| | - Jeannette Winter
- Center for Integrated Protein Science Munich (CiPS(M)) at the Department Chemie, Technische Universität München, 85747 Garching, Germany.
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