1
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Sprenger M, Siemers M, Krautwurst S, Papenfort K. Small RNAs direct attack and defense mechanisms in a quorum sensing phage and its host. Cell Host Microbe 2024; 32:727-738.e6. [PMID: 38579715 DOI: 10.1016/j.chom.2024.03.010] [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: 11/21/2023] [Revised: 02/02/2024] [Accepted: 03/13/2024] [Indexed: 04/07/2024]
Abstract
Many, if not all, bacteria use quorum sensing (QS) to control collective behaviors, and more recently, QS has also been discovered in bacteriophages (phages). Phages can produce communication molecules of their own, or "listen in" on the host's communication processes, to switch between lytic and lysogenic modes of infection. Here, we study the interaction of Vibrio cholerae with the lysogenic phage VP882, which is activated by the QS molecule DPO. We discover that induction of VP882 results in the binding of phage transcripts to the major RNA chaperone Hfq, which in turn outcompetes and downregulates host-encoded small RNAs (sRNAs). VP882 itself also encodes Hfq-binding sRNAs, and we demonstrate that one of these sRNAs, named VpdS, promotes phage replication by regulating host and phage mRNA levels. We further show that host-encoded sRNAs can antagonize phage replication by downregulating phage mRNA expression and thus might be part of the host's phage defense arsenal.
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Affiliation(s)
- Marcel Sprenger
- Friedrich Schiller University, Institute of Microbiology, 07745 Jena, Germany
| | - Malte Siemers
- Friedrich Schiller University, Institute of Microbiology, 07745 Jena, Germany; Microverse Cluster, Friedrich Schiller University Jena, 07743 Jena, Germany
| | | | - Kai Papenfort
- Friedrich Schiller University, Institute of Microbiology, 07745 Jena, Germany; Microverse Cluster, Friedrich Schiller University Jena, 07743 Jena, Germany.
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2
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Andrews K, Landeryou T, Sicheritz-Pontén T, Nale JY. Diverse Prophage Elements of Salmonella enterica Serovars Show Potential Roles in Bacterial Pathogenicity. Cells 2024; 13:514. [PMID: 38534358 DOI: 10.3390/cells13060514] [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: 12/22/2023] [Revised: 01/26/2024] [Accepted: 03/08/2024] [Indexed: 03/28/2024] Open
Abstract
Nontyphoidal salmonellosis is an important foodborne and zoonotic infection that causes significant global public health concern. Diverse serovars are multidrug-resistant and encode several virulence indicators; however, little is known on the role prophages play in driving these traits. Here, we extracted prophages from seventy-five Salmonella genomes which represent the fifteen important serovars in the United Kingdom. We analyzed the intact prophages for the presence of virulence genes and established their genomic relationships. We identified 615 prophages from the Salmonella strains, from which 195 prophages are intact, 332 are incomplete, while 88 are questionable. The average prophage carriage was found to be 'extreme' in S. Heidelberg, S. Inverness, and S. Newport (10.2-11.6 prophages/strain), 'high' in S. Infantis, S. Stanley, S. Typhimurium, and S. Virchow (8.2-9.0 prophages/strain), 'moderate' in S. Agona, S. Braenderup, S. Bovismorbificans, S. Choleraesuis, S. Dublin, and S. Java (6.0-7.8 prophages/strain), and 'low' in S. Javiana and S. Enteritidis (5.8 prophages/strain). Cumulatively, 61 virulence genes (1500 gene copies) were detected from representative intact prophages and linked to Salmonella delivery/secretion system (42.62%), adherence (32.7%), magnesium uptake (3.88%), regulation (5%), stress/survival (1.6%), toxins (10%), and antivirulence (1.6%). Diverse clusters were formed among the intact prophages and with bacteriophages of other enterobacteria, suggesting different lineages and associations. Our work provides a strong body of data to support the contributions diverse prophages make to the pathogenicity of Salmonella, including thirteen previously unexplored serovars.
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Affiliation(s)
- Kirstie Andrews
- Centre for Epidemiology and Planetary Health, School of Veterinary Medicine, Scotland's Rural College, Inverness IV2 5NA, UK
| | - Toby Landeryou
- Centre for Epidemiology and Planetary Health, School of Veterinary Medicine, Scotland's Rural College, Inverness IV2 5NA, UK
| | - Thomas Sicheritz-Pontén
- Center for Evolutionary Hologenomics, The Globe Institute, University of Copenhagen, 1353 Copenhagen, Denmark
| | - Janet Yakubu Nale
- Centre for Epidemiology and Planetary Health, School of Veterinary Medicine, Scotland's Rural College, Inverness IV2 5NA, UK
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3
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Elgrably-Weiss M, Hussain F, Georg J, Shraiteh B, Altuvia S. Balanced cell division is secured by two different regulatory sites in OxyS RNA. RNA (NEW YORK, N.Y.) 2024; 30:124-135. [PMID: 38071477 PMCID: PMC10798246 DOI: 10.1261/rna.079836.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/09/2023] [Indexed: 01/18/2024]
Abstract
The hydrogen peroxide-induced small RNA OxyS has been proposed to originate from the 3' UTR of a peroxide mRNA. Unexpectedly, phylogenetic OxyS targetome predictions indicate that most OxyS targets belong to the category of "cell cycle," including cell division and cell elongation. Previously, we reported that Escherichia coli OxyS inhibits cell division by repressing expression of the essential transcription termination factor nusG, thereby leading to the expression of the KilR protein, which interferes with the function of the major cell division protein, FtsZ. By interfering with cell division, OxyS brings about cell-cycle arrest, thus allowing DNA damage repair. Cell division and cell elongation are opposing functions to the extent that inhibition of cell division requires a parallel inhibition of cell elongation for the cells to survive. In this study, we report that in addition to cell division, OxyS inhibits mepS, which encodes an essential peptidoglycan endopeptidase that is responsible for cell elongation. Our study indicates that cell-cycle arrest and balancing between cell division and cell elongation are important and conserved functions of the oxidative stress-induced sRNA OxyS.
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Affiliation(s)
- Maya Elgrably-Weiss
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, 91120 Jerusalem, Israel
| | - Fayyaz Hussain
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, 79104 Freiburg, Germany
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, 79104 Freiburg, Germany
| | - Bushra Shraiteh
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, 91120 Jerusalem, Israel
| | - Shoshy Altuvia
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, 91120 Jerusalem, Israel
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4
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T N, Govindarajan S, Munavar MH. trans-translation system is important for maintaining genome integrity during DNA damage in bacteria. Res Microbiol 2023; 174:104136. [PMID: 37690591 DOI: 10.1016/j.resmic.2023.104136] [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: 04/21/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/12/2023]
Abstract
DNA integrity in bacteria is regulated by various factors that act on the DNA. trans-translation has previously been shown to be important for the survival of Escherichia coli cells exposed to certain DNA-damaging agents. However, the mechanisms underlying this sensitivity are poorly understood. In this study, we explored the involvement of the trans-translation system in the maintenance of genome integrity using various DNA-damaging agents and mutant backgrounds. Relative viability assays showed that SsrA-defective cells were sensitive to DNA-damaging agents, such as nalidixic acid (NA), ultraviolet radiation (UV), and methyl methanesulfonate (MMS). The viability of SsrA-defective cells was rescued by deleting sulA, although the expression of SulA was not more pronounced in SsrA-defective cells than in wild-type cells. Live cell imaging using a Gam-GFP fluorescent reporter showed increased double-strand breaks (DSBs) in SsrA-defective cells during DNA damage. We also showed that the ribosome rescue function of SsrA was sufficient for DNA damage tolerance. DNA damage sensitivity can be alleviated by partial uncoupling of transcription and translation by using sub-lethal concentrations of ribosome inhibiting antibiotic (tetracycline) or by mutating the gene coding for RNase H (rnhA). Taken together, our results highlight the importance of trans-translation system in maintaining genome integrity and bacterial survival during DNA damage.
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Affiliation(s)
- Nagarajan T
- Department of Molecular Biology, School of Biological Sciences, Madurai Kamaraj University, Madurai, India; Department of Biological Sciences, SRM University-AP, Amaravati, India
| | | | - M Hussain Munavar
- Department of Molecular Biology, School of Biological Sciences, Madurai Kamaraj University, Madurai, India.
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5
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Early antitermination in the atypical coliphage mEp021 mediated by the Gp17 protein. Arch Virol 2023; 168:92. [PMID: 36795170 DOI: 10.1007/s00705-023-05721-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 01/09/2023] [Indexed: 02/17/2023]
Abstract
The coliphage mEp021 belongs to a phage group with a unique immunity repressor, and its life cycle requires the host factor Nus. mEp021 has been classified as non-lambdoid based on its specific characteristics. The mEp021 genome carries a gene encoding an Nλ-like antiterminator protein, termed Gp17, and three nut sites (nutL, nutR1, and nutR2). Analysis of plasmid constructs containing these nut sites, a transcription terminator, and a GFP reporter gene showed high levels of fluorescence when Gp17 was expressed, but not in its absence. Like lambdoid N proteins, Gp17 has an arginine-rich motif (ARM), and mutations in its arginine codons inhibit its function. In infection assays using the mutant phage mEp021ΔGp17::Kan (where gp17 has been deleted), gene transcripts located downstream of transcription terminators were obtained only when Gp17 was expressed. In contrast to phage lambda, mEp021 virus particle production was partially restored (>1/3 relative to wild type) when nus mutants (nusA1, nusB5, nusC60, and nusE71) were infected with mEp021 and Gp17 was overexpressed. Our results suggest that RNA polymerase reads through the third nut site (nutR2), which is more than 7.9 kbp downstream of nutR1.
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6
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Govindarajan S, Borges A, Karambelkar S, Bondy-Denomy J. Distinct Subcellular Localization of a Type I CRISPR Complex and the Cas3 Nuclease in Bacteria. J Bacteriol 2022; 204:e0010522. [PMID: 35389256 PMCID: PMC9112876 DOI: 10.1128/jb.00105-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/17/2022] [Indexed: 12/30/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems are prokaryotic adaptive immune systems that have been well characterized biochemically, but in vivo spatiotemporal regulation and cell biology remain largely unaddressed. Here, we used fluorescent fusion proteins introduced at the chromosomal CRISPR-Cas locus to study the localization of the type I-F CRISPR-Cas system in Pseudomonas aeruginosa. When lacking a target in the cell, the Cascade complex is broadly nucleoid bound, while Cas3 is diffuse in the cytoplasm. When targeted to an integrated prophage, however, the CRISPR RNA (crRNA)-guided type I-F Cascade complex and a majority of Cas3 molecules in the cell are recruited to a single focus. Nucleoid association of the Csy proteins that form the Cascade complex is crRNA dependent and specifically inhibited by the expression of anti-CRISPR AcrIF2, which blocks protospacer adjacent motif (PAM) binding. The Cas9 nuclease is also nucleoid localized, only when single guide RNA (sgRNA) bound, which is abolished by the PAM-binding inhibitor AcrIIA4. Our findings reveal PAM-dependent nucleoid surveillance and spatiotemporal regulation in type I CRISPR-Cas that separates the nuclease-helicase Cas3 from the crRNA-guided surveillance complex. IMPORTANCE CRISPR-Cas systems, the prokaryotic adaptive immune systems, are largely understood using structural biology, biochemistry, and genetics. How CRISPR-Cas effectors are organized within cells is currently not well understood. By investigating the cell biology of the type I-F CRISPR-Cas system, we show that the surveillance complex, which "patrols" the cell to find targets, is largely nucleoid bound, while Cas3 nuclease is cytoplasmic. Nucleoid localization is also conserved for class 2 CRISPR-Cas single protein effector Cas9. Our observation of differential localization of the surveillance complex and Cas3 reveals a new layer of posttranslational spatiotemporal regulation to prevent autoimmunity.
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Affiliation(s)
- Sutharsan Govindarajan
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Adair Borges
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Shweta Karambelkar
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, California, USA
- Innovative Genomics Institute, Berkeley, California, USA
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7
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Abstract
Small RNAs (sRNAs) are important gene regulators in bacteria, but it is unclear how new sRNAs originate and become part of regulatory networks that coordinate bacterial response to environmental stimuli. Using a covariance modeling-based approach, we analyzed the presence of hundreds of sRNAs in more than a thousand genomes across Enterobacterales, a bacterial order with a confluence of factors that allows robust genome-scale sRNA analyses: several well-studied organisms with fairly conserved genome structures, an established phylogeny, and substantial nucleotide diversity within a narrow evolutionary space. We discovered that a majority of sRNAs arose recently, and uncovered protein-coding genes as a potential source from which new sRNAs arise. A detailed investigation of the emergence of OxyS, a peroxide-responding sRNA, revealed that it evolved from a fragment of a peroxidase messenger RNA. Importantly, although it replaced the ancestral peroxidase, OxyS continues to be part of the ancestral peroxide-response regulon, indicating that an sRNA that arises from a protein-coding gene would inherently be part of the parental protein's regulatory network. This new insight provides a fresh framework for understanding sRNA origin and regulatory integration in bacteria.
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Affiliation(s)
- Madeline C Krieger
- Department of Biology, Portland State University, Portland, OR, USA
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - H Auguste Dutcher
- Department of Biology, Portland State University, Portland, OR, USA
- Laboratory of Genetics and Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Andrew J Ashford
- Department of Biology, Portland State University, Portland, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Rahul Raghavan
- Department of Biology, Portland State University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, The University of Texas at San Antonio, San Antonio, TX, USA
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8
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Clostridioides difficile - phage relationship the RNA way. Curr Opin Microbiol 2021; 66:1-10. [PMID: 34922145 DOI: 10.1016/j.mib.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/06/2021] [Accepted: 11/28/2021] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile (formerly Clostridium difficile)-associated diarrhea is currently the most frequently occurring nosocomial diarrhea worldwide. During its infection cycle this pathogen needs to survive in phage-rich gut communities. Recent data strongly suggest that regulatory RNAs control gene expression in C. difficile and many of these RNAs appear to modulate C. difficile-phage interactions. Of the 200 regulatory RNAs identified by deep sequencing and targeted approaches, many function as antitoxins within type I toxin-antitoxin modules and CRISPR RNAs for anti-phage defenses. In this review, we discuss recent insights into the role of RNAs in modulating interactions between C. difficile and phages in light of intriguing data in other prokaryotes.
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9
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Basu P, Altuvia S. RelA binding of mRNAs modulates translation or sRNA-mRNA basepairing depending on the position of the GGAG site. Mol Microbiol 2021; 117:143-159. [PMID: 34523176 DOI: 10.1111/mmi.14812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/12/2021] [Accepted: 09/12/2021] [Indexed: 11/26/2022]
Abstract
Previously, we reported that RelA protein facilitates Hfq-mediated mRNA-sRNA regulation by binding sRNAs carrying a Shine-Dalgarno-like GGAG sequence. In turn, sRNA-Hfq monomers are stabilized, enabling the attachment of more Hfq subunits to form a functional hexamer. Here, using CLIP-seq, we present a global analysis of RelA-bound RNAs showing that RelA interacts with sRNAs as well as with mRNAs carrying a GGAG motif. RelA binding of mRNAs carrying GGAG at position -7 relative to the initiation codon (AUG) inhibits translation by interfering with the binding of 30S ribosomes. The extent of inhibition depends on the distance of GGAG relative to the AUG, as shortening the spacing between GGAG and AUG abrogates RelA-mediated inhibition. Interestingly, RelA binding of target mRNAs carrying GGAG in the coding sequence or close to AUG facilitates target gene regulation by sRNA partners that lack GGAG. However, translation inhibition caused by RelA binding of mRNAs carrying GGAG at position -7 relative to the AUG renders sRNA-mRNA basepairing regulation ineffective. Our study indicates that by binding RNAs carrying GGAG the ribosome-associated RelA protein inhibits translation of specific newly synthesized incoming mRNAs or enables basepairing regulation by their respective sRNA partners, thereby introducing a new regulatory concept for the bacterial response.
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Affiliation(s)
- Pallabi Basu
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Shoshy Altuvia
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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10
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Zhang K, Zhang Y, Wang Z, Li Y, Xu H, Jiao X, Li Q. Characterization of CRISPR array in Salmonella enterica from asymptomatic people and patients. Int J Food Microbiol 2021; 355:109338. [PMID: 34333443 DOI: 10.1016/j.ijfoodmicro.2021.109338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
Salmonella enterica is a major foodborne pathogen causing symptomatic diseases or asymptomatic infections in humans. To reveal the genetic difference of Salmonella strains from patients to that from asymptomatic people, we used CRISPR typing to analyze the phylogenetic relationship of 180 clinical strains during 2017-2018 in Jiangsu, China. The CRISPR typing divided these isolates into 76 CRISPR types with a discriminatory power of 97.6%. S. Typhimurium and its monophasic variants of 6 CRISPR types are the significant serotypes causing both human diseases and asymptomatic infection, while S. Enteritidis mainly resulted in diseases and shared one CRISPR type. The spacer HadB20 displayed as a new molecular marker to differentiate ST34-S. Typhimurium monophasic variant from ST19-S. Typhimurium. S. Derby, S. London, and S. Senftenberg frequently caused asymptomatic infection with diverse CRISPR types, while S. Mbandaka and S. Meleagridis, occasionally isolated from patients, had conserved CRISPR types. Additionally, 30 of 516 newly identified spacers showed homology to sequences in both plasmids and bacteriophages. Interestingly, some spacers from one serotype showed homology to the correspondent prophage or plasmid sequences in another serotype; and more than two spacers identified in one strain showed homology to the sequences located in the identical plasmids or phages, revealing the constant evolution of Salmonella CRISPR arrays during the interactions between bacteria and phages or plasmids.
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Affiliation(s)
- Kai Zhang
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China
| | - Yue Zhang
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China
| | - Zhenyu Wang
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China
| | - Yang Li
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China
| | - Haiyan Xu
- Nantong Center for Disease Control and Prevention, Nantong, China
| | - Xinan Jiao
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China
| | - Qiuchun Li
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China.
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11
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Basu P, Elgrably-Weiss M, Hassouna F, Kumar M, Wiener R, Altuvia S. RNA binding of Hfq monomers promotes RelA-mediated hexamerization in a limiting Hfq environment. Nat Commun 2021; 12:2249. [PMID: 33883550 PMCID: PMC8060364 DOI: 10.1038/s41467-021-22553-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 03/20/2021] [Indexed: 02/02/2023] Open
Abstract
The RNA chaperone Hfq, acting as a hexamer, is a known mediator of post-transcriptional regulation, expediting basepairing between small RNAs (sRNAs) and their target mRNAs. However, the intricate details associated with Hfq-RNA biogenesis are still unclear. Previously, we reported that the stringent response regulator, RelA, is a functional partner of Hfq that facilitates Hfq-mediated sRNA-mRNA regulation in vivo and induces Hfq hexamerization in vitro. Here we show that RelA-mediated Hfq hexamerization requires an initial binding of RNA, preferably sRNA to Hfq monomers. By interacting with a Shine-Dalgarno-like sequence (GGAG) in the sRNA, RelA stabilizes the initially unstable complex of RNA bound-Hfq monomer, enabling the attachment of more Hfq subunits to form a functional hexamer. Overall, our study showing that RNA binding to Hfq monomers is at the heart of RelA-mediated Hfq hexamerization, challenges the previous concept that only Hfq hexamers can bind RNA.
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Affiliation(s)
- Pallabi Basu
- grid.9619.70000 0004 1937 0538Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Maya Elgrably-Weiss
- grid.9619.70000 0004 1937 0538Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Fouad Hassouna
- grid.9619.70000 0004 1937 0538Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Manoj Kumar
- grid.9619.70000 0004 1937 0538Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Reuven Wiener
- grid.9619.70000 0004 1937 0538Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Shoshy Altuvia
- grid.9619.70000 0004 1937 0538Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
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12
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Abstract
Enterohemorrhagic E. coli is a significant human pathogen that can cause severe disease due to the release of Shiga toxins. The toxins are encoded within lysogenic bacteriophage and controlled by antitermination of the phage late promoter, PR′. This promoter is always active, but terminated immediately downstream during lysogeny. A byproduct of antitermination regulation is transcription of a short RNA that is thought to be nonfunctional. Here we demonstrate that in Shiga toxin-encoding phages, this short RNA is a Hfq-binding regulatory small RNA. The small RNA represses toxin production threefold under lysogenic conditions and promotes high cell density growth. Lysogenic bacteriophages are highly abundant and our results suggest that antiterminated phage promoters may be a rich source of regulatory RNAs. Enterohemorrhagic Escherichia coli is a significant human pathogen that causes disease ranging from hemorrhagic colitis to hemolytic uremic syndrome. The latter can lead to potentially fatal renal failure and is caused by the release of Shiga toxins that are encoded within lambdoid bacteriophages. The toxins are encoded within the late transcript of the phage and are regulated by antitermination of the PR′ late promoter during lytic induction of the phage. During lysogeny, the late transcript is prematurely terminated at tR′ immediately downstream of PR′, generating a short RNA that is a byproduct of antitermination regulation. We demonstrate that this short transcript binds the small RNA chaperone Hfq, and is processed into a stable 74-nt regulatory small RNA that we have termed StxS. StxS represses expression of Shiga toxin 1 under lysogenic conditions through direct interactions with the stx1AB transcript. StxS acts in trans to activate expression of the general stress response sigma factor, RpoS, through direct interactions with an activating seed sequence within the 5′ UTR. Activation of RpoS promotes high cell density growth under nutrient-limiting conditions. Many phages utilize antitermination to regulate the lytic/lysogenic switch and our results demonstrate that short RNAs generated as a byproduct of this regulation can acquire regulatory small RNA functions that modulate host fitness.
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13
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Bloch S, Lewandowska N, Węgrzyn G, Nejman-Faleńczyk B. Bacteriophages as sources of small non-coding RNA molecules. Plasmid 2020; 113:102527. [PMID: 32768406 DOI: 10.1016/j.plasmid.2020.102527] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 01/10/2023]
Abstract
Bacteriophages play an essential role in the transferring of genes that contribute to the bacterial virulence and whose products are dangerous to human health. Interestingly, phages carrying virulence genes are mostly temperate and in contrast to lytic phages undergo both lysogenic and lytic cycles. Importantly, expression of the majority of phage genes and subsequent production of phage encoded proteins is suppressed during lysogeny. The expression of the majority of phage genes is tightly linked to lytic development. Among others, small non-coding RNAs (sRNAs) of phage origin are involved in the regulation of phage gene expression and thus play an important role in both phage and host development. In the case of bacteria, sRNAs affect processes such as virulence, colonization ability, motility and cell growth or death. In turn, in the case of phages, they play essential roles during the early stage of infection, maintaining the state of lysogeny and silencing the expression of late structural genes, thereby regulating the transition between phage life cycles. Interestingly, sRNAs have been identified in both lytic and temperate phages and they have been discussed in this work according to this classification. Particular attention was paid to viral sRNAs resembling eukaryotic microRNAs.
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Affiliation(s)
- Sylwia Bloch
- Laboratory of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kładki 24, 80-822 Gdańsk, Poland
| | - Natalia Lewandowska
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland
| | - Bożena Nejman-Faleńczyk
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
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14
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Abstract
The opportunistic human pathogen Pseudomonas aeruginosa possesses multiple quorum sensing systems that regulate and coordinate production of virulence factors and adaptation to different environments. Despite extensive research, the regulatory elements that play a role in this complex network are still not fully understood. By using several RNA sequencing techniques, we were able to identify a small regulatory RNA we named RhlS. RhlS increases translation of RhlI, a key enzyme in the quorum sensing pathway, and represses the fpvA mRNA encoding one of the siderophore pyoverdine receptors. Our results highlight a new regulatory layer of P. aeruginosa quorum sensing and contribute to the growing understanding of the role regulatory RNAs play in bacterial physiology. N-Acyl homoserine lactone (AHL) quorum sensing (QS) controls expression of over 200 genes in Pseudomonas aeruginosa. There are two AHL regulatory systems: the LasR-LasI circuit and the RhlR-RhlI system. We mapped transcription termination sites affected by AHL QS in P. aeruginosa, and in doing so we identified AHL-regulated small RNAs (sRNAs). Of interest, we noted that one particular sRNA was located within the rhlI locus. We found that rhlI, which encodes the enzyme that produces the AHL N-butanoyl-homoserine lactone (C4-HSL), is controlled by a 5′ untranslated region (UTR)-derived sRNA we name RhlS. We also identified an antisense RNA encoded opposite the beginning of the rhlI open reading frame, which we name asRhlS. RhlS accumulates as wild-type cells enter stationary phase and is required for the production of normal levels of C4-HSL through activation of rhlI translation. RhlS also directly posttranscriptionally regulates at least one other unlinked gene, fpvA. The asRhlS appears to be expressed at maximal levels during logarithmic growth, and we suggest RhlS may act antagonistically to the asRhlS to regulate rhlI translation. The rhlI-encoded sRNAs represent a novel aspect of RNA-mediated tuning of P. aeruginosa QS.
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15
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Abstract
The study of bacteriophages (phages) and prophages has provided key insights into almost every cellular process as well as led to the discovery of unexpected new mechanisms and the development of valuable tools. This is exemplified for RNA-based regulation. For instance, the characterization and exploitation of the antiphage CRISPR (clustered regularly interspaced short palindromic repeat) systems is revolutionizing molecular biology. Phage-encoded proteins such as the RNA-binding MS2 protein, which is broadly used to isolate tagged RNAs, also have been developed as valuable tools. Hfq, the RNA chaperone protein central to the function of many base-pairing small RNAs (sRNAs), was first characterized as a bacterial host factor required for Qβ phage replication. The ongoing studies of RNAs are continuing to reveal regulatory connections between infecting phages, prophages, and bacteria and to provide novel insights. There are bacterial and prophage sRNAs that regulate prophage genes, which impact bacterial virulence as well as bacterial cell killing. Conversely, phage- and prophage-encoded sRNAs modulate the expression of bacterial genes modifying metabolism. An interesting subcategory of the prophage-encoded sRNAs are sponge RNAs that inhibit the activities of bacterial-encoded sRNAs. Phages also affect posttranscriptional regulation in bacteria through proteins that inhibit or alter the activities of key bacterial proteins involved in posttranscriptional regulation. However, what is most exciting about phage and prophage research, given the millions of phage-encoded genes that have not yet been characterized, is the vast potential for discovering new RNA regulators and novel mechanisms and for gaining insight into the evolution of regulatory RNAs.
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16
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Wahl A, Battesti A, Ansaldi M. Prophages in Salmonella enterica: a driving force in reshaping the genome and physiology of their bacterial host? Mol Microbiol 2018; 111:303-316. [PMID: 30466179 PMCID: PMC7380047 DOI: 10.1111/mmi.14167] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2018] [Indexed: 12/11/2022]
Abstract
Thanks to the exponentially increasing number of publicly available bacterial genome sequences, one can now estimate the important contribution of integrated viral sequences to the diversity of bacterial genomes. Indeed, temperate bacteriophages are able to stably integrate the genome of their host through site‐specific recombination and transmit vertically to the host siblings. Lysogenic conversion has been long acknowledged to provide additional functions to the host, and particularly to bacterial pathogen genomes where prophages contribute important virulence factors. This review aims particularly at highlighting the current knowledge and questions about lysogeny in Salmonella genomes where functional prophages are abundant, and where genetic interactions between host and prophages are of particular importance for human health considerations.
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Affiliation(s)
- Astrid Wahl
- Laboratoire de Chimie Bactérienne, UMR7283, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France
| | - Aurélia Battesti
- Laboratoire de Chimie Bactérienne, UMR7283, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France
| | - Mireille Ansaldi
- Laboratoire de Chimie Bactérienne, UMR7283, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, Aix-Marseille Université, Marseille, France
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17
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Abstract
Despite the central role of bacterial noncoding small RNAs (sRNAs) in posttranscriptional regulation, little is understood about their evolution. Here we compile what has been studied to date and trace a life cycle of sRNAs-from their mechanisms of emergence, through processes of change and frequent neofunctionalization, to their loss from bacterial lineages. Because they possess relatively unrestrictive structural requirements, we find that sRNA origins are varied, and include de novo emergence as well as formation from preexisting genetic elements via duplication events and horizontal gene transfer. The need for only partial complementarity to their mRNA targets facilitates apparent rapid change, which also contributes to significant challenges in tracing sRNAs across broad evolutionary distances. We document that recently emerged sRNAs in particular evolve quickly, mirroring dynamics observed in microRNAs, their functional analogs in eukaryotes. Mutations in mRNA-binding regions, transcriptional regulator or sigma factor binding sites, and protein-binding regions are all likely sources of shifting regulatory roles of sRNAs. Finally, using examples from the few evolutionary studies available, we examine cases of sRNA loss and describe how these may be the result of adaptive in addition to neutral processes. We highlight the need for more-comprehensive analyses of sRNA evolutionary patterns as a means to improve novel sRNA detection, enhance genome annotation, and deepen our understanding of regulatory networks in bacteria.
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18
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Raina M, King A, Bianco C, Vanderpool CK. Dual-Function RNAs. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0032-2018. [PMID: 30191807 PMCID: PMC6130917 DOI: 10.1128/microbiolspec.rwr-0032-2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Indexed: 12/30/2022] Open
Abstract
Bacteria are known to use RNA, either as mRNAs encoding proteins or as noncoding small RNAs (sRNAs), to regulate numerous biological processes. However, a few sRNAs have two functions: they act as base-pairing RNAs and encode a small protein with additional regulatory functions. Thus, these so called "dual-function" sRNAs can serve as both a riboregulator and an mRNA. In some cases, these two functions can act independently within the same pathway, while in other cases, the base-pairing function and protein function act in different pathways. Here, we discuss the five known dual-function sRNAs-SgrS from enteric species, RNAIII and Psm-mec from Staphylococcus aureus, Pel RNA from Streptococcus pyogenes, and SR1 from Bacillus subtilis-and review their mechanisms of action and roles in regulating diverse biological processes. We also discuss the prospect of finding additional dual-function sRNAs and future challenges in studying the overlap and competition between the functions.
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Affiliation(s)
- Medha Raina
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Alisa King
- Department of Microbiology, University of Illinois, Urbana, IL 61801
| | - Colleen Bianco
- Department of Microbiology, University of Illinois, Urbana, IL 61801
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19
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Abstract
Piscirickettsia salmonis, a fastidious Gram-negative intracellular facultative bacterium, is the causative agent o Piscirickettsiosis. P. salmonis has broad host range with a nearly worldwide distribution, causing significant mortality. The molecular regulatory mechanisms of P. salmonis pathogenesis are relatively unknown, mainly due to its difficult in vitro culture and genomic differences between genogroups. Bacterial non-coding RNAs (ncRNAs) are important post-transcriptional regulators of bacterial physiology and virulence that are predominantly transcribed from intergenic regions (trans-acting) or antisense strand of open reading frames (cis-acting). The repertoire of ncRNAs present in the genome of P. salmonis and its possible role in bacterial physiology and pathogenesis are unknown. Here, we predicted and analyzed the core ncRNAs of P. salmonis base on structure and correlate this prediction to RNA sequencing data. We identified a total of 69 ncRNA classes related to tRNAs, rRNA, thermoregulators, antitoxins, ribozymes, riboswitches, miRNAs and antisense-RNAs. Among these ncRNAs, 29 classes of ncRNAs are shared between all P. salmonis genomes, constituting the core ncRNAs of P. salmonis. The ncRNA core of P. salmonis could serve to develop diagnostic tools and explore the role of ncRNA in fish pathogenesis.
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20
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Zhuge X, Sun Y, Xue F, Tang F, Ren J, Li D, Wang J, Jiang M, Dai J. A Novel PhoP/PhoQ Regulation Pathway Modulates the Survival of Extraintestinal Pathogenic Escherichia coli in Macrophages. Front Immunol 2018; 9:788. [PMID: 29719540 PMCID: PMC5913352 DOI: 10.3389/fimmu.2018.00788] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/29/2018] [Indexed: 12/12/2022] Open
Abstract
The extraintestinal pathogenic Escherichia coli (ExPEC) is a typical facultative intracellular bacterial pathogen. Sensing the environmental stimuli and undertaking adaptive change are crucial for ExPEC to successfully colonize in specific extraintestinal niches. The previous studies show that pathogens exploit two-component systems (TCSs) in response to the host environments during its infection. The PhoP/PhoQ is a typical TCS which is ubiquitous in Gram-negative bacteria. However, there is an incompletely understanding about critical regulatory roles of PhoP/PhoQ in ExPEC pathogenesis. Conjugative ColV-related plasmids are responsible for ExPEC virulence, which is associated with ExPEC zoonotic risk. In this study, the molecular characteristics of HlyF, Mig-14 ortholog (Mig-14p), and OmpT variant (OmpTp) encoded by ColV plasmids were identified. Mig-14p and OmpTp played important roles in conferring ExPEC resistance to cationic antimicrobial peptides (CAMPs) during the infection. Moreover, HlyF and Mig-14p acted as intracellular survival factors to promote ExPEC resistance to macrophages killing. The hlyF and Mig-14p formed an operon in ExPEC ColV plasmid, and PhoP acted as a transcriptional activator of hlyF operon by directly binding to the P hlyF promoter. The acidic pH and CAMPs could additively stimulate ExPEC PhoQ/PhoP activities to upregulate the expression of HlyF and Mig-14p. Our studies revealed that the novel PhoP/PhoQ-HlyF signaling pathway directly upregulates the production of ExPEC outer membrane vesicles. Furthermore, our study first clarified that this PhoP/PhoQ-HlyF pathway was essential for ExPEC intracellular survival in macrophages. It was required to prevent the fusion of ExPEC-containing phagosomes with lysosomes. Moreover, PhoP/PhoQ-HlyF pathway facilitated the inhibition of the phagolysosomal acidification and disruption of the phagolysosomal membranes. In addition, this pathway might promote the formation of ExPEC-containing autophagosome during ExPEC replication in macrophages. Collectively, our studies suggested that PhoP/PhoQ system and CloV plasmids could facilitate ExPEC survival and replication within macrophages.
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Affiliation(s)
- Xiangkai Zhuge
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Center for Post-Doctoral Studies of Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yu Sun
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Feng Xue
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Fang Tang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jianluan Ren
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Dezhi Li
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Juanfang Wang
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Min Jiang
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Jianjun Dai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
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21
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Azam MS, Vanderpool CK. Translational regulation by bacterial small RNAs via an unusual Hfq-dependent mechanism. Nucleic Acids Res 2018; 46:2585-2599. [PMID: 29294046 PMCID: PMC5861419 DOI: 10.1093/nar/gkx1286] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 12/08/2017] [Accepted: 12/21/2017] [Indexed: 01/06/2023] Open
Abstract
In bacteria, the canonical mechanism of translational repression by small RNAs (sRNAs) involves sRNA-mRNA base pairing that occludes the ribosome binding site (RBS), directly preventing translation. In this mechanism, the sRNA is the direct regulator, while the RNA chaperone Hfq plays a supporting role by stabilizing the sRNA. There are a few examples where the sRNA does not directly interfere with ribosome binding, yet translation of the target mRNA is still inhibited. Mechanistically, this non-canonical regulation by sRNAs is poorly understood. Our previous work demonstrated repression of the mannose transporter manX mRNA by the sRNA SgrS, but the regulatory mechanism was unknown. Here, we report that manX translation is controlled by a molecular role-reversal mechanism where Hfq, not the sRNA, is the direct repressor. Hfq binding adjacent to the manX RBS is required for sRNA-mediated translational repression. Translation of manX is also regulated by another sRNA, DicF, via the same non-canonical Hfq-dependent mechanism. Our results suggest that the sRNAs recruit Hfq to its binding site or stabilize the mRNA-Hfq complex. This work adds to the growing number of examples of diverse mechanisms of translational regulation by sRNAs in bacteria.
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Affiliation(s)
- Muhammad S Azam
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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22
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Barshishat S, Elgrably-Weiss M, Edelstein J, Georg J, Govindarajan S, Haviv M, Wright PR, Hess WR, Altuvia S. OxyS small RNA induces cell cycle arrest to allow DNA damage repair. EMBO J 2018; 37:413-426. [PMID: 29237698 PMCID: PMC5793797 DOI: 10.15252/embj.201797651] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 11/13/2017] [Accepted: 11/20/2017] [Indexed: 11/10/2022] Open
Abstract
To maintain genome integrity, organisms employ DNA damage response, the underlying principles of which are conserved from bacteria to humans. The bacterial small RNA OxyS of Escherichia coli is induced upon oxidative stress and has been implicated in protecting cells from DNA damage; however, the mechanism by which OxyS confers genome stability remained unknown. Here, we revealed an OxyS-induced molecular checkpoint relay, leading to temporary cell cycle arrest to allow damage repair. By repressing the expression of the essential transcription termination factor nusG, OxyS enables read-through transcription into a cryptic prophage encoding kilR The KilR protein interferes with the function of the major cell division protein FtsZ, thus imposing growth arrest. This transient growth inhibition facilitates DNA damage repair, enabling cellular recovery, thereby increasing viability following stress. The OxyS-mediated growth arrest represents a novel tier of defense, introducing a new regulatory concept into bacterial stress response.
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Affiliation(s)
- Shir Barshishat
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Maya Elgrably-Weiss
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Jonathan Edelstein
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Sutharsan Govindarajan
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Meytal Haviv
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Patrick R Wright
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Shoshy Altuvia
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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23
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Ellis MJ, Carfrae LA, Macnair CR, Trussler RS, Brown ED, Haniford DB. Silent but deadly: IS200 promotes pathogenicity in Salmonella Typhimurium. RNA Biol 2017; 15:176-181. [PMID: 29120256 DOI: 10.1080/15476286.2017.1403001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Bacterial transposons were long thought of as selfish mobile genetic elements that propagate at the expense of 'host' bacterium fitness. However, limited transposition can benefit the host organism by promoting DNA rearrangements and facilitating horizontal gene transfer. Here we discuss and provide context for our recently published work which reported the surprising finding that an otherwise dormant transposon, IS200, encodes a regulatory RNA in Salmonella Typhimurium. This previous work identified a trans-acting sRNA that is encoded in the 5'UTR of IS200 transposase mRNA (tnpA). This sRNA represses expression of genes encoded within Salmonella Pathogenicity Island 1 (SPI-1), and accordingly limits invasion into non-phagocytic cells in vitro. We present new data here that shows IS200 elements are important for colonization of the mouse gastrointestinal tract. We discuss our previous and current findings in the context of transposon biology and suggest that otherwise 'silent' transposons may in fact play an important role in controlling host gene expression.
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Affiliation(s)
- Michael J Ellis
- a Department of Biochemistry , University of Western Ontario , London , ON Canada
| | - Lindsey A Carfrae
- b Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research , McMaster University , Hamilton , ON Canada
| | - Craig R Macnair
- b Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research , McMaster University , Hamilton , ON Canada
| | - Ryan S Trussler
- a Department of Biochemistry , University of Western Ontario , London , ON Canada
| | - Eric D Brown
- b Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research , McMaster University , Hamilton , ON Canada
| | - David B Haniford
- a Department of Biochemistry , University of Western Ontario , London , ON Canada
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24
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Ellis MJ, Trussler RS, Charles O, Haniford DB. A transposon-derived small RNA regulates gene expression in Salmonella Typhimurium. Nucleic Acids Res 2017; 45:5470-5486. [PMID: 28335027 PMCID: PMC5435999 DOI: 10.1093/nar/gkx094] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/06/2017] [Indexed: 12/30/2022] Open
Abstract
Bacterial sRNAs play an important role in regulating many cellular processes including metabolism, outer membrane homeostasis and virulence. Although sRNAs were initially found in intergenic regions, there is emerging evidence that protein coding regions of the genome are a rich reservoir of sRNAs. Here we report that the 5΄UTR of IS200 transposase mRNA (tnpA) is processed to produce regulatory RNAs that affect expression of over 70 genes in Salmonella Typhimurium. We provide evidence that the tnpA derived sRNA base-pairs with invF mRNA to repress expression. As InvF is a transcriptional activator of SPI-1 encoded and other effector proteins, tnpA indirectly represses these genes. We show that deletion of IS200 elements in S. Typhimurium increases invasion in vitro and reduces growth rate, while over-expression of tnpA suppresses invasion. Our work indicates that tnpA acts as an sRNA ‘sponge’ that sets a threshold for activation of Salmonella pathogenicity island (SPI)-1 effector proteins and identifies a new class of ‘passenger gene’ for bacterial transposons, providing the first example of a bacterial transposon producing a regulatory RNA that controls host gene expression.
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Affiliation(s)
- Michael J Ellis
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ryan S Trussler
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Onella Charles
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - David B Haniford
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
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25
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Small and Smaller-sRNAs and MicroRNAs in the Regulation of Toxin Gene Expression in Prokaryotic Cells: A Mini-Review. Toxins (Basel) 2017; 9:toxins9060181. [PMID: 28556797 PMCID: PMC5488031 DOI: 10.3390/toxins9060181] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/09/2017] [Accepted: 05/26/2017] [Indexed: 12/14/2022] Open
Abstract
Non-coding small RNAs (sRNAs) have been identified in the wide range of bacteria (also pathogenic species) and found to play an important role in the regulation of many processes, including toxin gene expression. The best characterized prokaryotic sRNAs regulate gene expression by base pairing with mRNA targets and fall into two broad classes: cis-encoded sRNAs (also called antisense RNA) and trans-acting sRNAs. Molecules from the second class are frequently considered as the most related to eukaryotic microRNAs. Interestingly, typical microRNA-size RNA molecules have also been reported in prokaryotic cells, although they have received little attention up to now. In this work we have collected information about all three types of small prokaryotic RNAs in the context of the regulation of toxin gene expression.
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26
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Hershko-Shalev T, Odenheimer-Bergman A, Elgrably-Weiss M, Ben-Zvi T, Govindarajan S, Seri H, Papenfort K, Vogel J, Altuvia S. Correction: Gifsy-1 Prophage IsrK with Dual Function as Small and Messenger RNA Modulates Vital Bacterial Machineries. PLoS Genet 2017; 13:e1006725. [PMID: 28410372 PMCID: PMC5391912 DOI: 10.1371/journal.pgen.1006725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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27
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Smirnov A, Wang C, Drewry LL, Vogel J. Molecular mechanism of mRNA repression in trans by a ProQ-dependent small RNA. EMBO J 2017; 36:1029-1045. [PMID: 28336682 PMCID: PMC5391140 DOI: 10.15252/embj.201696127] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 02/05/2017] [Accepted: 02/10/2017] [Indexed: 12/26/2022] Open
Abstract
Research into post-transcriptional control of mRNAs by small noncoding RNAs (sRNAs) in the model bacteria Escherichia coli and Salmonella enterica has mainly focused on sRNAs that associate with the RNA chaperone Hfq. However, the recent discovery of the protein ProQ as a common binding partner that stabilizes a distinct large class of structured sRNAs suggests that additional RNA regulons exist in these organisms. The cellular functions and molecular mechanisms of these new ProQ-dependent sRNAs are largely unknown. Here, we report in Salmonella Typhimurium the mode-of-action of RaiZ, a ProQ-dependent sRNA that is made from the 3' end of the mRNA encoding ribosome-inactivating protein RaiA. We show that RaiZ is a base-pairing sRNA that represses in trans the mRNA of histone-like protein HU-α. RaiZ forms an RNA duplex with the ribosome-binding site of hupA mRNA, facilitated by ProQ, to prevent 30S ribosome loading and protein synthesis of HU-α. Similarities and differences between ProQ- and Hfq-mediated regulation will be discussed.
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Affiliation(s)
- Alexandre Smirnov
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Chuan Wang
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Lisa L Drewry
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany .,Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
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28
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Gimpel M, Brantl S. Dual-function small regulatory RNAs in bacteria. Mol Microbiol 2016; 103:387-397. [PMID: 27750368 DOI: 10.1111/mmi.13558] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/10/2016] [Accepted: 10/11/2016] [Indexed: 12/31/2022]
Abstract
Dual-function sRNAs are a subgroup of small regulatory RNAs that act on the one hand as base-pairing sRNAs to inhibit or activate target gene expression and on the other hand as peptide-encoding mRNAs that function either in the same or in another metabolic pathway. Here, we review and compare the five currently known and intensively characterized dual-function sRNAs with regard to their two functions, their biological role, their evolutionary conservation and their requirements for RNA chaperones. Furthermore, we summarize the data available on five potential dual-function sRNAs, whose base-pairing function is well established whereas the role of their encoded peptides has not yet been elucidated. In addition, we provide three examples for RNAs with more than one function that do not fall into the above-mentioned category. With the application of RNAseq, peptidomics and transcriptomics it can be expected that the number of dual-function sRNAs will considerably increase within the next years, thus enhancing our knowledge on the regulatory potential of these RNAs.
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Affiliation(s)
- Matthias Gimpel
- Biologisch-Pharmazeutische Fakultät, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, AG Bakteriengenetik, Philosophenweg 12, Jena, D-07743, Germany
| | - Sabine Brantl
- Biologisch-Pharmazeutische Fakultät, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, AG Bakteriengenetik, Philosophenweg 12, Jena, D-07743, Germany
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29
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Fröhlich KS, Papenfort K. Interplay of regulatory RNAs and mobile genetic elements in enteric pathogens. Mol Microbiol 2016; 101:701-13. [DOI: 10.1111/mmi.13428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Kathrin S. Fröhlich
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
| | - Kai Papenfort
- Department of Biology I, Microbiology; Ludwig-Maximilians-University Munich; 82152 Martinsried Germany
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