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Differential Chromosome- and Plasmid-Borne Resistance of Escherichia coli hfq Mutants to High Concentrations of Various Antibiotics. Int J Mol Sci 2021; 22:ijms22168886. [PMID: 34445592 PMCID: PMC8396180 DOI: 10.3390/ijms22168886] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 12/14/2022] Open
Abstract
The Hfq protein is a bacterial RNA chaperone, involved in many molecular interactions, including control of actions of various small RNA regulatory molecules. We found that the presence of Hfq was required for survival of plasmid-containing Escherichia coli cells against high concentrations of chloramphenicol (plasmid p27cmr), tetracycline (pSC101, pBR322) and ampicillin (pBR322), as hfq+ strains were more resistant to these antibiotics than the hfq-null mutant. In striking contrast, production of Hfq resulted in low resistance to high concentrations of kanamycin when the antibiotic-resistance marker was chromosome-borne, with deletion of hfq resulting in increasing bacterial survival. These results were observed both in solid and liquid medium, suggesting that antibiotic resistance is an intrinsic feature of these strains rather than a consequence of adaptation. Despite its major role as RNA chaperone, which also affects mRNA stability, Hfq was not found to significantly affect kan and tet mRNAs turnover. Nevertheless, kan mRNA steady-state levels were higher in the hfq-null mutant compared to the hfq+ strain, suggesting that Hfq can act as a repressor of kan expression.This observation does correlate with the enhanced resistance to high levels of kanamycin observed in the hfq-null mutant. Furthermore, dependency on Hfq for resistance to high doses of tetracycline was found to depend on plasmid copy number, which was only observed when the resistance marker was expressed from a low copy plasmid (pSC101) but not from a medium copy plasmid (pBR322). This suggests that Hfq may influence survival against high doses of antibiotics through mechanisms that remain to be determined. Studies with pBR322Δrom may also suggest an interplay between Hfq and Rom in the regulation of ColE1-like plasmid replication. Results of experiments with a mutant devoid of the part of the hfq gene coding for the C-terminal region of Hfq suggested that this region, as well as the N-terminal region, may be involved in the regulation of expression of antibiotic resistance in E. coli independently.
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Gómez-García G, Ruiz-Enamorado A, Yuste L, Rojo F, Moreno R. Expression of the ISPpu9 transposase of Pseudomonas putida KT2440 is regulated by two small RNAs and the secondary structure of the mRNA 5'-untranslated region. Nucleic Acids Res 2021; 49:9211-9228. [PMID: 34379788 PMCID: PMC8450116 DOI: 10.1093/nar/gkab672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/23/2021] [Accepted: 07/26/2021] [Indexed: 11/20/2022] Open
Abstract
Insertion sequences (ISs) are mobile genetic elements that only carry the information required for their own transposition. Pseudomonas putida KT2440, a model bacterium, has seven copies of an IS called ISPpu9 inserted into repetitive extragenic palindromic sequences. This work shows that the gene for ISPpu9 transposase, tnp, is regulated by two small RNAs (sRNAs) named Asr9 and Ssr9, which are encoded upstream and downstream of tnp, respectively. The tnp mRNA has a long 5′-untranslated region (5′-UTR) that can fold into a secondary structure that likely includes the ribosome-binding site (RBS). Mutations weakening this structure increased tnp mRNA translation. Asr9, an antisense sRNA complementary to the 5′-UTR, was shown to be very stable. Eliminating Asr9 considerably reduced tnp mRNA translation, suggesting that it helps to unfold this secondary structure, exposing the RBS. Ectopic overproduction of Asr9 increased the transposition frequency of a new ISPpu9 entering the cell by conjugation, suggesting improved tnp expression. Ssr9 has significant complementarity to Asr9 and annealed to it in vitro forming an RNA duplex; this would sequester it and possibly facilitate its degradation. Thus, the antisense Asr9 sRNA likely facilitates tnp expression, improving transposition, while Ssr9 might counteract Asr9, keeping tnp expression low.
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Affiliation(s)
- Guillermo Gómez-García
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
| | - Angel Ruiz-Enamorado
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
| | - Luis Yuste
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
| | - Fernando Rojo
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
| | - Renata Moreno
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid 28049, Spain
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Liu S, Yuan S, Gao X, Tao X, Yu W, Li X, Chen S, Xu A. Functional regulation of an ancestral RAG transposon ProtoRAG by a trans-acting factor YY1 in lancelet. Nat Commun 2020; 11:4515. [PMID: 32908127 PMCID: PMC7481187 DOI: 10.1038/s41467-020-18261-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 08/09/2020] [Indexed: 01/04/2023] Open
Abstract
The discovery of ancestral RAG transposons in early deuterostomia reveals the origin of vertebrate V(D)J recombination. Here, we analyze the functional regulation of a RAG transposon, ProtoRAG, in lancelet. We find that a specific interaction between the cis-acting element within the TIR sequences of ProtoRAG and a trans-acting factor, lancelet YY1-like (bbYY1), is important for the transcriptional regulation of lancelet RAG-like genes (bbRAG1L and bbRAG2L). Mechanistically, bbYY1 suppresses the transposition of ProtoRAG; meanwhile, bbYY1 promotes host DNA rejoins (HDJ) and TIR-TIR joints (TTJ) after TIR-dependent excision by facilitating the binding of bbRAG1L/2 L to TIR-containing DNA, and by interacting with the bbRAG1L/2 L complex. Our data thus suggest that bbYY1 has dual functions in fine-tuning the activity of ProtoRAG and maintaining the genome stability of the host.
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Affiliation(s)
- Song Liu
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Shaochun Yuan
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266237, Qingdao, People's Republic of China.
| | - Xiaoman Gao
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Xin Tao
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Wenjuan Yu
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Xu Li
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Shangwu Chen
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Anlong Xu
- State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China.
- School of Life Sciences, Beijing University of Chinese Medicine, 100029, Beijing, People's Republic of China.
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Ritzert JT, Minasov G, Embry R, Schipma MJ, Satchell KJF. The Cyclic AMP Receptor Protein Regulates Quorum Sensing and Global Gene Expression in Yersinia pestis during Planktonic Growth and Growth in Biofilms. mBio 2019; 10:e02613-19. [PMID: 31744922 PMCID: PMC6867900 DOI: 10.1128/mbio.02613-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 12/16/2022] Open
Abstract
Cyclic AMP (cAMP) receptor protein (Crp) is an important transcriptional regulator of Yersinia pestis Expression of crp increases during pneumonic plague as the pathogen depletes glucose and forms large biofilms within lungs. To better understand control of Y. pestis Crp, we determined a 1.8-Å crystal structure of the protein-cAMP complex. We found that compared to Escherichia coli Crp, C helix amino acid substitutions in Y. pestis Crp did not impact the cAMP dependency of Crp to bind DNA promoters. To investigate Y. pestis Crp-regulated genes during plague pneumonia, we performed RNA sequencing on both wild-type and Δcrp mutant bacteria growing in planktonic and biofilm states in minimal media with glucose or glycerol. Y. pestis Crp was found to dramatically alter expression of hundreds of genes in a manner dependent upon carbon source and growth state. Gel shift assays confirmed direct regulation of the malT and ptsG promoters, and Crp was then linked to Y. pestis growth on maltose as a sole carbon source. Iron regulation genes ybtA and fyuA were found to be indirectly regulated by Crp. A new connection between carbon source and quorum sensing was revealed as Crp was found to regulate production of acyl-homoserine lactones (AHLs) through direct and indirect regulation of genes for AHL synthetases and receptors. AHLs were subsequently identified in the lungs of Y. pestis-infected mice when crp expression was highest in Y. pestis biofilms. Thus, in addition to the well-studied pla gene, other Crp-regulated genes likely have important functions during plague infection.IMPORTANCE Bacterial pathogens have evolved extensive signaling pathways to translate environmental signals into changes in gene expression. While Crp has long been appreciated for its role in regulating metabolism of carbon sources in many bacterial species, transcriptional profiling has revealed that this protein regulates many other aspects of bacterial physiology. The plague pathogen Y. pestis requires this global regulator to survive in blood, skin, and lungs. During disease progression, this organism adapts to changes within these niches. In addition to regulating genes for metabolism of nonglucose sugars, we found that Crp regulates genes for virulence, metal acquisition, and quorum sensing by direct or indirect mechanisms. Thus, this single transcriptional regulator, which responds to changes in available carbon sources, can regulate multiple critical behaviors for causing disease.
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Affiliation(s)
- Jeremy T Ritzert
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - George Minasov
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Genomics of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ryan Embry
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Matthew J Schipma
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Center for Structural Genomics of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Escherichia coli as a host for metabolic engineering. Metab Eng 2018; 50:16-46. [DOI: 10.1016/j.ymben.2018.04.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/21/2022]
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Babakhani S, Oloomi M. Transposons: the agents of antibiotic resistance in bacteria. J Basic Microbiol 2018; 58:905-917. [PMID: 30113080 DOI: 10.1002/jobm.201800204] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/08/2018] [Accepted: 07/31/2018] [Indexed: 12/29/2022]
Abstract
Transposons are a group of mobile genetic elements that are defined as a DNA sequence. Transposons can jump into different places of the genome; for this reason, they are called jumping genes. However, some transposons are always kept at the insertion site in the genome. Most transposons are inactivated and as a result, cannot move. Transposons are divided into two main groups: retrotransposons (class І) and DNA transposons (class ІІ). Retrotransposons are often found in eukaryotes. DNA transposons can be found in both eukaryotes and prokaryotes. The bacterial transposons belong to the DNA transposons and the Tn family, which are usually the carrier of additional genes for antibiotic resistance. Transposons can transfer from a plasmid to other plasmids or from a DNA chromosome to plasmid and vice versa that cause the transmission of antibiotic resistance genes in bacteria. The treatment of bacterial infectious diseases is difficult because of existing antibiotic resistance that part of this antibiotic resistance is caused by transposons. Bacterial infectious diseases are responsible for the increasing rise in world mortality rate. In this review, transposons and their roles have been studied in bacterial antibiotic resistance, in detail.
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Affiliation(s)
- Sajad Babakhani
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mana Oloomi
- Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
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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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Cech GM, Szalewska-Pałasz A, Kubiak K, Malabirade A, Grange W, Arluison V, Węgrzyn G. The Escherichia Coli Hfq Protein: An Unattended DNA-Transactions Regulator. Front Mol Biosci 2016; 3:36. [PMID: 27517037 PMCID: PMC4963395 DOI: 10.3389/fmolb.2016.00036] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/13/2016] [Indexed: 11/17/2022] Open
Abstract
The Hfq protein was discovered in Escherichia coli as a host factor for bacteriophage Qβ RNA replication. Subsequent studies indicated that Hfq is a pleiotropic regulator of bacterial gene expression. The regulatory role of Hfq is ascribed mainly to its function as an RNA-chaperone, facilitating interactions between bacterial non-coding RNA and its mRNA target. Thus, it modulates mRNA translation and stability. Nevertheless, Hfq is able to interact with DNA as well. Its role in the regulation of DNA-related processes has been demonstrated. In this mini-review, it is discussed how Hfq interacts with DNA and what is the role of this protein in regulation of DNA transactions. Particularly, Hfq has been demonstrated to be involved in the control of ColE1 plasmid DNA replication, transposition, and possibly also transcription. Possible mechanisms of these Hfq-mediated regulations are described and discussed.
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Affiliation(s)
- Grzegorz M Cech
- Department of Molecular Biology, University of Gdańsk Gdańsk, Poland
| | | | - Krzysztof Kubiak
- Department of Molecular Biology, University of GdańskGdańsk, Poland; Laboratoire Léon Brillouin, CEA, Centre National de la Recherche Scientifique, Université Paris Saclay, CEA SaclayGif-sur-Yvette, France; IPCMS/Centre National de la Recherche ScientifiqueStrasbourg, France
| | - Antoine Malabirade
- Laboratoire Léon Brillouin, CEA, Centre National de la Recherche Scientifique, Université Paris Saclay, CEA Saclay Gif-sur-Yvette, France
| | - Wilfried Grange
- IPCMS/Centre National de la Recherche ScientifiqueStrasbourg, France; Universite Paris Diderot, UFR Science du VivantParis, France
| | - Veronique Arluison
- Laboratoire Léon Brillouin, CEA, Centre National de la Recherche Scientifique, Université Paris Saclay, CEA SaclayGif-sur-Yvette, France; Universite Paris Diderot, UFR Science du VivantParis, France
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk Gdańsk, Poland
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Ellis MJ, Haniford DB. Riboregulation of bacterial and archaeal transposition. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:382-98. [DOI: 10.1002/wrna.1341] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/07/2016] [Accepted: 01/10/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Michael J. Ellis
- Department of Biochemistry; University of Western Ontario; London Canada
| | - David B. Haniford
- Department of Biochemistry; University of Western Ontario; London Canada
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10
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Gebert D, Rosenkranz D. RNA-based regulation of transposon expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:687-708. [DOI: 10.1002/wrna.1310] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/08/2015] [Accepted: 09/13/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Daniel Gebert
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
| | - David Rosenkranz
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
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Ellis MJ, Trussler RS, Haniford DB. A cis-encoded sRNA, Hfq and mRNA secondary structure act independently to suppress IS200 transposition. Nucleic Acids Res 2015; 43:6511-27. [PMID: 26044710 PMCID: PMC4513863 DOI: 10.1093/nar/gkv584] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/22/2015] [Indexed: 12/13/2022] Open
Abstract
IS200 is found throughout Enterobacteriaceae and transposes at a notoriously low frequency. In addition to the transposase protein (TnpA), IS200 encodes an uncharacterized Hfq-binding sRNA that is encoded opposite to the tnpA 5'UTR. In the current work we asked if this sRNA represses tnpA expression. We show here that the IS200 sRNA (named art200 for antisense regulator of transposase IS200) basepairs with tnpA to inhibit translation initiation. Unexpectedly, art200-tnpA pairing is limited to 40 bp, despite 90 nt of perfect complementarity. Additionally, we show that Hfq and RNA secondary structure in the tnpA 5'UTR each repress tnpA expression in an art200-independent manner. Finally, we show that disrupting translational control of tnpA expression leads to increased IS200 transposition in E. coli. The current work provides new mechanistic insight into why IS200 transposition is so strongly suppressed. The possibility of art200 acting in trans to regulate a yet-unidentified target is discussed as well as potential applications of the IS200 system for designing novel riboregulators.
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Affiliation(s)
- Michael J Ellis
- Department of Biochemistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Ryan S Trussler
- Department of Biochemistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - David B Haniford
- Department of Biochemistry, University of Western Ontario, London, ON, N6A 5C1, Canada
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Papenfort K, Vanderpool CK. Target activation by regulatory RNAs in bacteria. FEMS Microbiol Rev 2015; 39:362-78. [PMID: 25934124 DOI: 10.1093/femsre/fuv016] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2015] [Indexed: 12/15/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) are commonly known to repress gene expression by base pairing to target mRNAs. In many cases, sRNAs base pair with and sequester mRNA ribosome-binding sites, resulting in translational repression and accelerated transcript decay. In contrast, a growing number of examples of translational activation and mRNA stabilization by sRNAs have now been documented. A given sRNA often employs a conserved region to interact with and regulate both repressed and activated targets. However, the mechanisms underlying activation differ substantially from repression. Base pairing resulting in target activation can involve sRNA interactions with the 5(') untranslated region (UTR), the coding sequence or the 3(') UTR of the target mRNAs. Frequently, the activities of protein factors such as cellular ribonucleases and the RNA chaperone Hfq are required for activation. Bacterial sRNAs, including those that function as activators, frequently control stress response pathways or virulence-associated functions required for immediate responses to changing environments. This review aims to summarize recent advances in knowledge regarding target mRNA activation by bacterial sRNAs, highlighting the molecular mechanisms and biological relevance of regulation.
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Affiliation(s)
- Kai Papenfort
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA Department of Biology I, Ludwig-Maximilians-University Munich, 82152 Martinsried, Germany
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Jiang K, Zhang C, Guttula D, Liu F, van Kan JA, Lavelle C, Kubiak K, Malabirade A, Lapp A, Arluison V, van der Maarel JRC. Effects of Hfq on the conformation and compaction of DNA. Nucleic Acids Res 2015; 43:4332-41. [PMID: 25824948 PMCID: PMC4417175 DOI: 10.1093/nar/gkv268] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 12/14/2022] Open
Abstract
Hfq is a bacterial pleiotropic regulator that mediates several aspects of nucleic acids metabolism. The protein notably influences translation and turnover of cellular RNAs. Although most previous contributions concentrated on Hfq's interaction with RNA, its association to DNA has also been observed in vitro and in vivo. Here, we focus on DNA-compacting properties of Hfq. Various experimental technologies, including fluorescence microscopy imaging of single DNA molecules confined inside nanofluidic channels, atomic force microscopy and small angle neutron scattering have been used to follow the assembly of Hfq on DNA. Our results show that Hfq forms a nucleoprotein complex, changes the mechanical properties of the double helix and compacts DNA into a condensed form. We propose a compaction mechanism based on protein-mediated bridging of DNA segments. The propensity for bridging is presumably related to multi-arm functionality of the Hfq hexamer, resulting from binding of the C-terminal domains to the duplex. Results are discussed in regard to previous results obtained for H-NS, with important implications for protein binding related gene regulation.
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Affiliation(s)
- Kai Jiang
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Ce Zhang
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Durgarao Guttula
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Fan Liu
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Jeroen A van Kan
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Christophe Lavelle
- Genomes Structure and Instability, Sorbonne Universities, National Museum of Natural History, Inserm U 1154, CNRS UMR 7196, 75005 Paris, France
| | - Krzysztof Kubiak
- Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA-Saclay, Gif sur Yvette Cedex 91191, France Department of Molecular Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Antoine Malabirade
- Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA-Saclay, Gif sur Yvette Cedex 91191, France
| | - Alain Lapp
- Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA-Saclay, Gif sur Yvette Cedex 91191, France
| | - Véronique Arluison
- Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA-Saclay, Gif sur Yvette Cedex 91191, France Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
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