1
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Marton Menendez A, Nesbitt DJ. Thermodynamic compensation to temperature extremes in B. subtilis vs T. maritima lysine riboswitches. Biophys J 2024; 123:3331-3345. [PMID: 39091026 DOI: 10.1016/j.bpj.2024.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 06/17/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
T. maritima and B. subtilis are bacteria that inhabit significantly different thermal environments, ∼80 vs. ∼40°C, yet employ similar lysine riboswitches to aid in the transcriptional regulation of the genes involved in the synthesis and transport of amino acids. Despite notable differences in G-C basepair frequency and primary sequence, the aptamer moieties of each riboswitch have striking similarities in tertiary structure, with several conserved motifs and long-range interactions. To explore genetic adaptation in extreme thermal environments, we compare the kinetic and thermodynamic behaviors in T. maritima and B. subtilis lysine riboswitches via single-molecule fluorescence resonance energy transfer analysis. Kinetic studies reveal that riboswitch folding rates increase with lysine concentration while the unfolding rates are independent of lysine. This indicates that both riboswitches bind lysine through an induced-fit ("bind-then-fold") mechanism, with lysine binding necessarily preceding conformational changes. Temperature-dependent van't Hoff studies reveal qualitative similarities in the thermodynamic landscapes for both riboswitches in which progression from the open, lysine-unbound state to both transition states (‡) and closed, lysine-bound conformations is enthalpically favored yet entropically penalized, with comparisons of enthalpic and entropic contributions extrapolated to a common [K+] = 100 mM in quantitative agreement. Finally, temperature-dependent Eyring analysis reveals the TMA and BSU riboswitches to have remarkably similar folding/unfolding rate constants when extrapolated to their respective (40 and 80°C) environmental temperatures. Such behavior suggests a shared strategy for ligand binding and aptamer conformational change in the two riboswitches, based on thermodynamic adaptations in number of G-C basepairs and/or modifications in tertiary structure that stabilize the ligand-unbound conformation to achieve biocompetence under both hyperthermophilic and mesothermophilic conditions.
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Affiliation(s)
- Andrea Marton Menendez
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado; Department of Chemistry, University of Colorado Boulder, Boulder, Colorado.
| | - David J Nesbitt
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado; Department of Chemistry, University of Colorado Boulder, Boulder, Colorado; Department of Physics, University of Colorado Boulder, Boulder, Colorado.
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2
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Liu Y, Ge H, Marchisio MA. Hybrid Boolean gates show that Cas12c controls transcription activation effectively in the yeast S. cerevisiae. Front Bioeng Biotechnol 2023; 11:1267174. [PMID: 37771576 PMCID: PMC10523329 DOI: 10.3389/fbioe.2023.1267174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/30/2023] [Indexed: 09/30/2023] Open
Abstract
Among CRISPR-Cas systems, type V CRISPR-Cas12c is of significant interest because Cas12c recognizes a very simple PAM (TN) and has the ability to silence gene expression without cleaving the DNA. We studied how new transcription factors for the yeast Saccharomyces cerevisiae can be built on Cas12c. We found that, upon fusion to a strong activation domain, Cas12c is an efficient activator. Its functionality was proved as a component of hybrid Boolean gates, i.e., logic circuits that mix transcriptional and translational control (the latter reached via tetracycline-responsive riboswitches). Moreover, Cas12c activity can be strongly inhibited by the anti-CRISPR AcrVA1 protein. Thus, Cas12c has the potential to be a new tool to control the activation of gene expression within yeast synthetic gene circuits.
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3
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Mahendran G, Jayasinghe OT, Thavakumaran D, Arachchilage GM, Silva GN. Key players in regulatory RNA realm of bacteria. Biochem Biophys Rep 2022; 30:101276. [PMID: 35592614 PMCID: PMC9111926 DOI: 10.1016/j.bbrep.2022.101276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Precise regulation of gene expression is crucial for living cells to adapt for survival in diverse environmental conditions. Among the common cellular regulatory mechanisms, RNA-based regulators play a key role in all domains of life. Discovery of regulatory RNAs have made a paradigm shift in molecular biology as many regulatory functions of RNA have been identified beyond its canonical roles as messenger, ribosomal and transfer RNA. In the complex regulatory RNA network, riboswitches, small RNAs, and RNA thermometers can be identified as some of the key players. Herein, we review the discovery, mechanism, and potential therapeutic use of these classes of regulatory RNAs mainly found in bacteria. Being highly adaptive organisms that inhabit a broad range of ecological niches, bacteria have adopted tight and rapid-responding gene regulation mechanisms. This review aims to highlight how bacteria utilize versatile RNA structures and sequences to build a sophisticated gene regulation network. The three major classes of prokaryotic ncRNAs and their characterized mechanisms of operation in gene regulation. sRNAs emerging as major players in global gene regulatory networks. Riboswitch mediated gene control mechanisms through on/off switches in response to ligand binding. RNA thermo sensors for temperature-dependent gene expression. Therapeutic importance of ncRNAs and computational approaches involved in the discovery of ncRNAs.
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Affiliation(s)
- Gowthami Mahendran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Oshadhi T. Jayasinghe
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Dhanushika Thavakumaran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, 06520-8103, USA
- PTC Therapeutics Inc, South Plainfield, NJ, 07080, USA
| | - Gayathri N. Silva
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Corresponding author.
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4
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Machtel P, Wasilewska-Burczyk A, Zacharjasz J, Grzywacz K. PTT-quant: a new method for direct identification and absolute quantification of premature transcription termination events, following the example of bacterial riboswitches. Appl Microbiol Biotechnol 2022; 106:1557-1570. [PMID: 35122156 PMCID: PMC8882085 DOI: 10.1007/s00253-022-11809-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 12/01/2022]
Abstract
Regulation of gene expression by premature termination of transcription has been well described in all domains of life, including metazoans, yeast, plants, and bacteria. Although methods for identification of such regulatory events by sequencing are available, the focused biochemical studies of the mechanism are hampered by lack of highly sensitive and accurate experimental methods. Here, we propose a new method for absolute quantification of premature transcription termination events, PTT-quant. It is based on highly sensitive two-step digital droplet PCR protocol, coupled with normalized cDNA synthesis attained by site-specific pre-cleavage of investigated transcripts with RNase H. As a consequence, our method enables the reliable and sensitive quantification of both, prematurely terminated and full-length transcripts. By application of our method to investigation of transcriptional riboswitches in Bacillus subtilis, we were able to precisely measure the dynamics of S-adenosylmethionine (SAM) riboswitch induction, which turned to be ~ 23% higher in comparison the results obtained without cDNA synthesis normalization. Key points • A novel method for quantification of premature transcription termination events was established. • PTT-quant measures absolute concentration of full-length and terminated transcripts. • RNase H and the digital droplet PCR technique is used in PTT-quant.
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Affiliation(s)
- Piotr Machtel
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Poznań, Poland
| | | | - Julian Zacharjasz
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Poznań, Poland
| | - Kamilla Grzywacz
- Institute of Bioorganic Chemistry Polish Academy of Sciences, Poznań, Poland.
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5
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Vargas-Junior V, Antunes D, Guimarães AC, Caffarena E. In silico investigation of riboswitches in fungi: structural and dynamical insights into TPP riboswitches in Aspergillus oryzae. RNA Biol 2022; 19:90-103. [PMID: 34989318 PMCID: PMC8786325 DOI: 10.1080/15476286.2021.2015174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Riboswitches are RNA sensors affecting post-transcriptional processes through their ability to bind to small molecules. Thiamine pyrophosphate (TPP) riboswitch plays a crucial role in regulating genes involved in synthesizing or transporting thiamine and phosphorylated derivatives in bacteria, archaea, plants, and fungi. Although TPP riboswitch is reasonably well known in bacteria, there is a gap in the knowledge of the fungal TPP riboswitches structure and dynamics, involving mainly sequence variation and TPP interaction with the aptamers. On the other hand, the increase of fungal infections and antifungal resistance raises the need for new antifungal therapies. In this work, we used computational approaches to build three-dimensional models for the three TPP riboswitches identified in Aspergillus oryzae, in which we studied their structure, dynamics, and binding free energy change (ΔGbind) with TPP. Interaction patterns between the TPP and the surrounding nucleotides were conserved among the three models, evidencing high structural conservation. Furthermore, we show that the TPP riboswitch from the A. oryzae NMT1 gene behaves similarly to the E. coli thiA gene concerning the ΔGbind. In contrast, mutations in the fungal TPP riboswitches from THI4 and the nucleoside transporter genes led to structural differences, affecting the binding-site volume, hydrogen bond occupancy, and ΔGbind. Besides, the number of water molecules surrounding TPP influenced the ΔGbind considerably. Notably, our ΔGbind estimation agreed with previous experimental data, reinforcing the relationship between sequence conservation and TPP interaction.
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Affiliation(s)
- Valdemir Vargas-Junior
- Computational Biophysics and Molecular Modeling Group, Scientific Computing Programme (Procc - Fiocruz), Rio de Janeiro, Brazil
| | - Deborah Antunes
- Laboratory of Functional Genomics and Bioinformatics, Oswaldo Cruz Institute (Ioc - Fiocruz), Rio de Janeiro, Brazil
| | - Ana Carolina Guimarães
- Laboratory of Functional Genomics and Bioinformatics, Oswaldo Cruz Institute (Ioc - Fiocruz), Rio de Janeiro, Brazil
| | - Ernesto Caffarena
- Computational Biophysics and Molecular Modeling Group, Scientific Computing Programme (Procc - Fiocruz), Rio de Janeiro, Brazil
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6
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Felden B, Augagneur Y. Diversity and Versatility in Small RNA-Mediated Regulation in Bacterial Pathogens. Front Microbiol 2021; 12:719977. [PMID: 34447363 PMCID: PMC8383071 DOI: 10.3389/fmicb.2021.719977] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial gene expression is under the control of a large set of molecules acting at multiple levels. In addition to the transcription factors (TFs) already known to be involved in global regulation of gene expression, small regulatory RNAs (sRNAs) are emerging as major players in gene regulatory networks, where they allow environmental adaptation and fitness. Developments in high-throughput screening have enabled their detection in the entire bacterial kingdom. These sRNAs influence a plethora of biological processes, including but not limited to outer membrane synthesis, metabolism, TF regulation, transcription termination, virulence, and antibiotic resistance and persistence. Almost always noncoding, they regulate target genes at the post-transcriptional level, usually through base-pair interactions with mRNAs, alone or with the help of dedicated chaperones. There is growing evidence that sRNA-mediated mechanisms of actions are far more diverse than initially thought, and that they go beyond the so-called cis- and trans-encoded classifications. These molecules can be derived and processed from 5' untranslated regions (UTRs), coding or non-coding sequences, and even from 3' UTRs. They usually act within the bacterial cytoplasm, but recent studies showed sRNAs in extracellular vesicles, where they influence host cell interactions. In this review, we highlight the various functions of sRNAs in bacterial pathogens, and focus on the increasing examples of widely diverse regulatory mechanisms that might compel us to reconsider what constitute the sRNA.
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Affiliation(s)
- Brice Felden
- Inserm, Bacterial Regulatory RNAs and Medicine (BRM) - UMR_S 1230, Rennes, France
| | - Yoann Augagneur
- Inserm, Bacterial Regulatory RNAs and Medicine (BRM) - UMR_S 1230, Rennes, France
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7
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The Role of RNA Secondary Structure in Regulation of Gene Expression in Bacteria. Int J Mol Sci 2021; 22:ijms22157845. [PMID: 34360611 PMCID: PMC8346122 DOI: 10.3390/ijms22157845] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 11/28/2022] Open
Abstract
Due to the high exposition to changing environmental conditions, bacteria have developed many mechanisms enabling immediate adjustments of gene expression. In many cases, the required speed and plasticity of the response are provided by RNA-dependent regulatory mechanisms. This is possible due to the very high dynamics and flexibility of an RNA structure, which provide the necessary sensitivity and specificity for efficient sensing and transduction of environmental signals. In this review, we will discuss the current knowledge about known bacterial regulatory mechanisms which rely on RNA structure. To better understand the structure-driven modulation of gene expression, we describe the basic theory on RNA structure folding and dynamics. Next, we present examples of multiple mechanisms employed by RNA regulators in the control of bacterial transcription and translation.
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8
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Bush JA, Williams CC, Meyer SM, Tong Y, Haniff HS, Childs-Disney JL, Disney MD. Systematically Studying the Effect of Small Molecules Interacting with RNA in Cellular and Preclinical Models. ACS Chem Biol 2021; 16:1111-1127. [PMID: 34166593 PMCID: PMC8867596 DOI: 10.1021/acschembio.1c00014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The interrogation and manipulation of biological systems by small molecules is a powerful approach in chemical biology. Ideal compounds selectively engage a target and mediate a downstream phenotypic response. Although historically small molecule drug discovery has focused on proteins and enzymes, targeting RNA is an attractive therapeutic alternative, as many disease-causing or -associated RNAs have been identified through genome-wide association studies. As the field of RNA chemical biology emerges, the systematic evaluation of target validation and modulation of target-associated pathways is of paramount importance. In this Review, through an examination of case studies, we outline the experimental characterization, including methods and tools, to evaluate comprehensively the impact of small molecules that target RNA on cellular phenotype.
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Affiliation(s)
- Jessica A Bush
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Christopher C Williams
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Samantha M Meyer
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Yuquan Tong
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Hafeez S Haniff
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Jessica L Childs-Disney
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Matthew D Disney
- The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
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9
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Born J, Weitzel K, Suess B, Pfeifer F. A Synthetic Riboswitch to Regulate Haloarchaeal Gene Expression. Front Microbiol 2021; 12:696181. [PMID: 34211452 PMCID: PMC8241225 DOI: 10.3389/fmicb.2021.696181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/21/2021] [Indexed: 11/13/2022] Open
Abstract
In recent years, synthetic riboswitches have become increasingly important to construct genetic circuits in all three domains of life. In bacteria, synthetic translational riboswitches are often employed that modulate gene expression by masking the Shine-Dalgarno (SD) sequence in the absence or presence of a cognate ligand. For (halo-)archaeal translation, a SD sequence is not strictly required. The application of synthetic riboswitches in haloarchaea is therefore limited so far, also because of the molar intracellular salt concentrations found in these microbes. In this study, we applied synthetic theophylline-dependent translational riboswitches in the archaeon Haloferax volcanii. The riboswitch variants A through E and E∗ were chosen since they not only mask the SD sequence but also the AUG start codon by forming a secondary structure in the absence of the ligand theophylline. Upon addition of the ligand, the ribosomal binding site and start codon become accessible for translation initiation. Riboswitch E mediated a dose-dependent, up to threefold activation of the bgaH reporter gene expression. Raising the salt concentration of the culture media from 3 to 4 M NaCl resulted in a 12-fold increase in the switching capacity of riboswitch E, and switching activity increased up to 26-fold when the cultivating temperature was reduced from 45 to 30°C. To construct a genetic circuit, riboswitch E was applied to regulate the synthesis of the transcriptional activator GvpE allowing a dose-dependent activation of the mgfp6 reporter gene under P pA promoter control.
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Affiliation(s)
| | | | - Beatrix Suess
- Synthetic RNA Biology, Department of Biology, Technical University Darmstadt, Darmstadt, Germany.,Centre of Synthetic Biology, Technical University Darmstadt, Darmstadt, Germany
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10
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Drogalis LK, Batey RT. Requirements for efficient ligand-gated co-transcriptional switching in designed variants of the B. subtilis pbuE adenine-responsive riboswitch in E. coli. PLoS One 2020; 15:e0243155. [PMID: 33259551 PMCID: PMC7707468 DOI: 10.1371/journal.pone.0243155] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/16/2020] [Indexed: 11/18/2022] Open
Abstract
Riboswitches, generally located in the 5'-leader of bacterial mRNAs, direct expression via a small molecule-dependent structural switch that informs the transcriptional or translational machinery. While the structure and function of riboswitch effector-binding (aptamer) domains have been intensely studied, only recently have the requirements for efficient linkage between small molecule binding and the structural switch in the cellular and co-transcriptional context begun to be actively explored. To address this aspect of riboswitch function, we have performed a structure-guided mutagenic analysis of the B. subtilis pbuE adenine-responsive riboswitch, one of the simplest riboswitches that employs a strand displacement switching mechanism to regulate transcription. Using a cell-based fluorescent protein reporter assay to assess ligand-dependent regulatory activity in E. coli, these studies revealed previously unrecognized features of the riboswitch. Within the aptamer domain, local and long-range conformational dynamics influenced by sequences within helices have a significant effect upon efficient regulatory switching. Sequence features of the expression platform including the pre-aptamer leader sequence, a toehold helix and an RNA polymerase pause site all serve to promote strong ligand-dependent regulation. By optimizing these features, we were able to improve the performance of the B. subtilis pbuE riboswitch in E. coli from 5.6-fold induction of reporter gene expression by the wild type riboswitch to over 120-fold in the top performing designed variant. Together, these data point to sequence and structural features distributed throughout the riboswitch required to strike a balance between rates of ligand binding, transcription and secondary structural switching via a strand exchange mechanism and yield new insights into the design of artificial riboswitches.
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MESH Headings
- Adenine/metabolism
- Aptamers, Nucleotide/chemistry
- Aptamers, Nucleotide/genetics
- Aptamers, Nucleotide/metabolism
- Bacillus subtilis/genetics
- Bacillus subtilis/metabolism
- Escherichia coli K12/genetics
- Genes, Reporter
- Genetic Variation
- Ligands
- Models, Genetic
- Models, Molecular
- Mutagenesis
- Nucleic Acid Conformation
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- Riboswitch/genetics
- Transcription, Genetic
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Affiliation(s)
- Lea K. Drogalis
- Department of Biochemistry, University of Colorado, Boulder, Colorado, United States of America
| | - Robert T. Batey
- Department of Biochemistry, University of Colorado, Boulder, Colorado, United States of America
- * E-mail:
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11
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Synthetic small regulatory RNAs in microbial metabolic engineering. Appl Microbiol Biotechnol 2020; 105:1-12. [PMID: 33201273 DOI: 10.1007/s00253-020-10971-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 02/06/2023]
Abstract
Small regulatory RNAs (sRNAs) finely control gene expression in prokaryotes and synthetic sRNA has become a useful high-throughput approach to tackle current challenges in metabolic engineering because of its many advantages compared to conventional gene knockouts. In this review, we first focus on the modular structures of sRNAs and rational design strategies of synthetic sRNAs on the basis of their modular structures. The wide applications of synthetic sRNAs in bacterial metabolic engineering, with or without the aid of heterogeneously expressed Hfq protein, were also covered. In addition, we give attention to the improvements in implementing synthetic sRNAs, which make the synthetic sRNA strategy universally applicable in metabolic engineering and synthetic biology. KEY POINTS: • Synthetic sRNAs can be rationally designed based on modular structures of natural sRNAs. • Synthetic sRNAs were widely used for metabolic engineering in various microorganisms. • Several technological improvements made the synthetic sRNA strategy more applicable.
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12
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McCluskey K, Boudreault J, St-Pierre P, Perez-Gonzalez C, Chauvier A, Rizzi A, Beauregard PB, Lafontaine DA, Penedo JC. Unprecedented tunability of riboswitch structure and regulatory function by sub-millimolar variations in physiological Mg2. Nucleic Acids Res 2020; 47:6478-6487. [PMID: 31045204 PMCID: PMC6614840 DOI: 10.1093/nar/gkz316] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 02/06/2023] Open
Abstract
Riboswitches are cis-acting regulatory RNA biosensors that rival the efficiency of those found in proteins. At the heart of their regulatory function is the formation of a highly specific aptamer–ligand complex. Understanding how these RNAs recognize the ligand to regulate gene expression at physiological concentrations of Mg2+ ions and ligand is critical given their broad impact on bacterial gene expression and their potential as antibiotic targets. In this work, we used single-molecule FRET and biochemical techniques to demonstrate that Mg2+ ions act as fine-tuning elements of the amino acid-sensing lysC aptamer's ligand-free structure in the mesophile Bacillus subtilis. Mg2+ interactions with the aptamer produce encounter complexes with strikingly different sensitivities to the ligand in different, yet equally accessible, physiological ionic conditions. Our results demonstrate that the aptamer adapts its structure and folding landscape on a Mg2+-tunable scale to efficiently respond to changes in intracellular lysine of more than two orders of magnitude. The remarkable tunability of the lysC aptamer by sub-millimolar variations in the physiological concentration of Mg2+ ions suggests that some single-aptamer riboswitches have exploited the coupling of cellular levels of ligand and divalent metal ions to tightly control gene expression.
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Affiliation(s)
- Kaley McCluskey
- SUPA School of Physics and Astronomy, University of St. Andrews, Scotland KY16 9SS, UK
| | - Julien Boudreault
- Département de Biologie, Université de Sherbrooke, Québec, Canada J1K 2R1
| | - Patrick St-Pierre
- Département de Biologie, Université de Sherbrooke, Québec, Canada J1K 2R1
| | - Cibran Perez-Gonzalez
- SUPA School of Physics and Astronomy, University of St. Andrews, Scotland KY16 9SS, UK.,Centre SÈVE, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Adrien Chauvier
- Département de Biologie, Université de Sherbrooke, Québec, Canada J1K 2R1
| | - Adrien Rizzi
- Département de Chimie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Pascale B Beauregard
- Centre SÈVE, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | | | - J Carlos Penedo
- SUPA School of Physics and Astronomy, University of St. Andrews, Scotland KY16 9SS, UK.,Biomedical Sciences Research Complex, School of Biology, University of St. Andrews, Scotland KY16 9ST, UK
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13
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Bédard ASV, Hien EDM, Lafontaine DA. Riboswitch regulation mechanisms: RNA, metabolites and regulatory proteins. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194501. [PMID: 32036061 DOI: 10.1016/j.bbagrm.2020.194501] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 12/17/2022]
Abstract
Riboswitches are RNA sensors that have been shown to modulate the expression of downstream genes by altering their structure upon metabolite binding. Riboswitches are unique among cellular regulators in that metabolite detection is strictly performed using RNA interactions with the sensed metabolite and in which no regulatory protein is needed to mediate the interaction. However, recent studies have shed light on riboswitch control mechanisms relying on protein regulators to harness metabolite binding for the mediation of gene expression, thereby increasing the range of cellular factors involved in riboswitch regulation. The interaction between riboswitches and proteins adds another level of evolutionary pressure as riboswitches must maintain key residues for metabolite detection, structural switching and protein binding sites. Here, we review regulatory mechanisms involving Escherichia coli riboswitches that have recently been shown to rely on regulatory proteins. We also discuss the implication of such protein-based riboswitch regulatory mechanisms for genetic regulation.
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Affiliation(s)
- Anne-Sophie Vézina Bédard
- Department of biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Elsa D M Hien
- Department of biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Daniel A Lafontaine
- Department of biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada.
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14
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Reprogramming bacteria with RNA regulators. Biochem Soc Trans 2019; 47:1279-1289. [DOI: 10.1042/bst20190173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/20/2022]
Abstract
Abstract
The revolution of genomics and growth of systems biology urged the creation of synthetic biology, an engineering discipline aiming at recreating and reprogramming cellular functions for industrial needs. There has been a huge effort in synthetic biology to develop versatile and programmable genetic regulators that would enable the precise control of gene expression. Synthetic RNA components have emerged as a solution, offering a diverse range of programmable functions, including signal sensing, gene regulation and the modulation of molecular interactions. Owing to their compactness, structure and way of action, several types of RNA devices that act on DNA, RNA and protein have been characterized and applied in synthetic biology. RNA-based approaches are more ‘economical' for the cell, since they are generally not translated. These RNA-based strategies act on a much shorter time scale than transcription-based ones and can be more efficient than protein-based mechanisms. In this review, we explore these RNA components as building blocks in the RNA synthetic biology field, first by explaining their natural mode of action and secondly discussing how these RNA components have been exploited to rewire bacterial regulatory circuitry.
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15
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Wang F, Sun LZ, Sun T, Chang S, Xu X. Helix-Based RNA Landscape Partition and Alternative Secondary Structure Determination. ACS OMEGA 2019; 4:15407-15413. [PMID: 31572840 PMCID: PMC6761681 DOI: 10.1021/acsomega.9b01430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
RNA is a versatile macromolecule with the ability to fold into and interconvert between multiple functional conformations. The elucidation of the RNA folding landscape, especially the knowledge of alternative structures, is critical to uncover the physical mechanism of RNA functions. Here, we introduce a helix-based strategy for RNA folding landscape partition and alternative secondary structure determination. The benchmark test of 27 RNAs involving alternative stable structures shows that the model has the ability to divide the whole landscape into distinct partitions at the secondary structure level and predict the representative structures for each partition. Furthermore, the predicted structures and equilibrium populations of metastable conformations for the 2'dG-sensing riboswitch reveal the allosteric conformational switch on transcript length, which is consistent with the experimental study, indicating the importance of metastable states for RNA-based gene regulation. The model delivers a starting point for the landscape-based strategy toward the RNA folding mechanism and functions.
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Affiliation(s)
- Fengfei Wang
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Li-Zhen Sun
- Department
of Applied Physics, Zhejiang University
of Technology, Hangzhou, Zhejiang 310023, China
| | - Tingting Sun
- Department
of Physics, Zhejiang University of Science
and Technology, Hangzhou, Zhejiang 310023, China
| | - Shan Chang
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Xiaojun Xu
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
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16
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Guo Y, Cui X, Ou L, Isowaki C, Masuda Y, Honjoh KI, Miyamoto T. Effects of Sucrose on Heat Resistance and Gene Expression in <i>Salmonella</i> Typhimurium. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2019. [DOI: 10.3136/fstr.25.903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Yue Guo
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University
| | - Xiaowen Cui
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University
| | - Liushu Ou
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University
| | - Chika Isowaki
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University
| | - Yoshimitsu Masuda
- Division of Food Science and Biotechnology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University
| | - Ken-ichi Honjoh
- Division of Food Science and Biotechnology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University
| | - Takahisa Miyamoto
- Division of Food Science and Biotechnology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University
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17
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Li X, Chen F, Xiao J, Chou SH, Li X, He J. Genome-wide Analysis of the Distribution of Riboswitches and Function Analyses of the Corresponding Downstream Genes in Prokaryotes. Curr Bioinform 2018. [DOI: 10.2174/1574893613666180423145812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Riboswitches are structured elements that usually reside in the noncoding
regions of mRNAs, with which various ligands bind to control a wide variety of downstream gene
expressions. To date, more than twenty different classes of riboswitches have been characterized to
sense various metabolites, including purines and their derivatives, coenzymes, amino acids, and metal
ions, etc.
</P><P>
Objective: This study aims to study the genome-wide analysis of the distribution of riboswitches and
function analyses of the corresponding downstream genes in prokaryotes.
Results:
In this study, we have completed a genome context analysis of 27 riboswitches to elucidate
their metabolic capacities of riboswitch-mediated gene regulation from the completely-sequenced 3,079
prokaryotic genomes. Furthermore, Cluster of Orthologous Groups of proteins (COG) annotation was
applied to predict and classify the possible functions of corresponding downstream genes of these
riboswitches. We found that they could all be successfully annotated and grouped into 20 different COG
functional categories, in which the two main clusters "coenzyme metabolism [H]" and "amino acid
transport and metabolism [E]" were the most significantly enriched.
Conclusion:
Riboswitches are found to be widespread in bacteria, among which three main classes of
TPP-, cobalamin- and SAM-riboswitch were the most widely distributed. We found a wide variety of
functions were associated with the corresponding downstream genes, suggesting that a wide extend of
regulatory roles were mediated by these riboswitches in prokaryotes.
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Affiliation(s)
- Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Fang Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jinfeng Xiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shan-Ho Chou
- Institute of Biochemistry and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Xuming Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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18
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Leistra AN, Curtis NC, Contreras LM. Regulatory non-coding sRNAs in bacterial metabolic pathway engineering. Metab Eng 2018; 52:190-214. [PMID: 30513348 DOI: 10.1016/j.ymben.2018.11.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/31/2018] [Accepted: 11/29/2018] [Indexed: 12/11/2022]
Abstract
Non-coding RNAs (ncRNAs) are versatile and powerful controllers of gene expression that have been increasingly linked to cellular metabolism and phenotype. In bacteria, identified and characterized ncRNAs range from trans-acting, multi-target small non-coding RNAs to dynamic, cis-encoded regulatory untranslated regions and riboswitches. These native regulators have inspired the design and construction of many synthetic RNA devices. In this work, we review the design, characterization, and impact of ncRNAs in engineering both native and exogenous metabolic pathways in bacteria. We also consider the opportunities afforded by recent high-throughput approaches for characterizing sRNA regulators and their corresponding networks to showcase their potential applications and impact in engineering bacterial metabolism.
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Affiliation(s)
- Abigail N Leistra
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA
| | - Nicholas C Curtis
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA.
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19
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Metabolic heterogeneity in clonal microbial populations. Curr Opin Microbiol 2018; 45:30-38. [DOI: 10.1016/j.mib.2018.02.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 11/22/2022]
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20
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The evolving interface between synthetic biology and functional metagenomics. Nat Chem Biol 2018; 14:752-759. [DOI: 10.1038/s41589-018-0100-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 06/13/2018] [Indexed: 12/15/2022]
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21
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Cheah HL, Raabe CA, Lee LP, Rozhdestvensky TS, Citartan M, Ahmed SA, Tang TH. Bacterial regulatory RNAs: complexity, function, and putative drug targeting. Crit Rev Biochem Mol Biol 2018; 53:335-355. [PMID: 29793351 DOI: 10.1080/10409238.2018.1473330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Over the past decade, RNA-deep sequencing has uncovered copious non-protein coding RNAs (npcRNAs) in bacteria. Many of them are key players in the regulation of gene expression, taking part in various regulatory circuits, such as metabolic responses to different environmental stresses, virulence, antibiotic resistance, and host-pathogen interactions. This has contributed to the high adaptability of bacteria to changing or even hostile environments. Their mechanisms include the regulation of transcriptional termination, modulation of translation, and alteration of messenger RNA (mRNA) stability, as well as protein sequestration. Here, the mechanisms of gene expression by regulatory bacterial npcRNAs are comprehensively reviewed and supplemented with well-characterized examples. This class of molecules and their mechanisms of action might be useful targets for the development of novel antibiotics.
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Affiliation(s)
- Hong-Leong Cheah
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Carsten A Raabe
- b Institute of Experimental Pathology, Centre for Molecular Biology of Inflammation , University of Münster , Münster , Germany.,c Brandenburg Medical School (MHB) , Neuruppin , Germany.,d Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation , University of Münster , Münster , Germany
| | - Li-Pin Lee
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Timofey S Rozhdestvensky
- e Medical Faculty, Transgenic Mouse and Genome Engineering Model Core Facility (TRAM) , University of Münster , Münster , Germany
| | - Marimuthu Citartan
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Siti Aminah Ahmed
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
| | - Thean-Hock Tang
- a Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia , Kepala Batas , Malaysia
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22
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Abstract
Noncoding RNAs (ncRNAs) regulating virulence have been identified in most pathogens. This review discusses RNA-mediated mechanisms exploited by bacterial pathogens to successfully infect and colonize their hosts. It discusses the most representative RNA-mediated regulatory mechanisms employed by two intracellular [Listeria monocytogenes and Salmonella enterica serovar Typhimurium (S. Typhimurium)] and two extracellular (Vibrio cholerae and Staphylococcus aureus) bacterial pathogens. We review the RNA-mediated regulators (e.g., thermosensors, riboswitches, cis- and trans-encoded RNAs) used for adaptation to the specific niches colonized by these bacteria (intestine, blood, or the intracellular environment, for example) in the framework of the specific pathophysiological aspects of the diseases caused by these microorganisms. A critical discussion of the newest findings in the field of bacterial ncRNAs shows how examples in model pathogens could pave the way for the discovery of new mechanisms in other medically important bacterial pathogens.
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Affiliation(s)
- Juan J Quereda
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France; , .,Institut National de la Santé et de la Recherche Médicale, U604, Paris F-75015, France.,Institut National de la Recherche Agronomique, USC2020, Paris F-75015, France
| | - Pascale Cossart
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France; , .,Institut National de la Santé et de la Recherche Médicale, U604, Paris F-75015, France.,Institut National de la Recherche Agronomique, USC2020, Paris F-75015, France
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23
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Wang X, He Q, Yang Y, Wang J, Haning K, Hu Y, Wu B, He M, Zhang Y, Bao J, Contreras LM, Yang S. Advances and prospects in metabolic engineering of Zymomonas mobilis. Metab Eng 2018; 50:57-73. [PMID: 29627506 DOI: 10.1016/j.ymben.2018.04.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/31/2018] [Accepted: 04/01/2018] [Indexed: 12/22/2022]
Abstract
Biorefinery of biomass-based biofuels and biochemicals by microorganisms is a competitive alternative of traditional petroleum refineries. Zymomonas mobilis is a natural ethanologen with many desirable characteristics, which makes it an ideal industrial microbial biocatalyst for commercial production of desirable bioproducts through metabolic engineering. In this review, we summarize the metabolic engineering progress achieved in Z. mobilis to expand its substrate and product ranges as well as to enhance its robustness against stressful conditions such as inhibitory compounds within the lignocellulosic hydrolysates and slurries. We also discuss a few metabolic engineering strategies that can be applied in Z. mobilis to further develop it as a robust workhorse for economic lignocellulosic bioproducts. In addition, we briefly review the progress of metabolic engineering in Z. mobilis related to the classical synthetic biology cycle of "Design-Build-Test-Learn", as well as the progress and potential to develop Z. mobilis as a model chassis for biorefinery practices in the synthetic biology era.
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Affiliation(s)
- Xia Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Qiaoning He
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Yongfu Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Jingwen Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Katie Haning
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Yun Hu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Bo Wu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Mingxiong He
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Yaoping Zhang
- DOE-Great Lakes Bioenergy Research Center (GLBRC), University of Wisconsin-Madison, Madison, WI, United States.
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Lydia M Contreras
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
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24
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Singh P, Kumar N, Jethva M, Yadav S, Kumari P, Thakur A, Kushwaha HR. Riboswitch regulation in cyanobacteria is independent of their habitat adaptations. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2018; 24:315-324. [PMID: 29515325 PMCID: PMC5834989 DOI: 10.1007/s12298-018-0504-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 12/13/2017] [Accepted: 01/02/2018] [Indexed: 01/17/2024]
Abstract
Cyanobacteria are one of the ancient bacterial species occupying a variety of habitats with diverse metabolic preferences. RNA regulators like riboswitches play significant role in controlling the gene expression in prokaryotes. The taxonomic distribution of riboswitches suggests that they might be one of the oldest mechanisms of gene control system. In this paper, we analyzed the distribution of different riboswitch families in various cyanobacterial genomes. It was observed that only four riboswitch classes were abundant in cyanobacteria, B12-element (Cob)/AdoCbl/AdoCbl-variant riboswitch being the most abundant. The analysis suggests that riboswitch mode of regulation is present in cyanobacterial species irrespective of their habitat types. A large number of unidentified genes regulated by riboswitches listed in this analysis indicate the wide range of targets for these riboswitch families. The analysis revealed a large number of genes regulated by riboswitches which may assist in elaborating the diversity among the cyanobacterial species.
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Affiliation(s)
- Payal Singh
- Synthetic Biology and Biofuel, ternational Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Nilesh Kumar
- Synthetic Biology and Biofuel, ternational Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Minesh Jethva
- Synthetic Biology and Biofuel, ternational Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Saurabh Yadav
- Department of Biotechnology, Hemwati Nandan Bahuguna Garhwal University, Srinagar Garhwal, Uttarakhand India
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25
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Liu W, Rochat T, Toffano-Nioche C, Le Lam TN, Bouloc P, Morvan C. Assessment of Bona Fide sRNAs in Staphylococcus aureus. Front Microbiol 2018. [PMID: 29515534 PMCID: PMC5826253 DOI: 10.3389/fmicb.2018.00228] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bacterial regulatory RNAs have been extensively studied for over a decade, and are progressively being integrated into the complex genetic regulatory network. Transcriptomic arrays, recent deep-sequencing data and bioinformatics suggest that bacterial genomes produce hundreds of regulatory RNAs. However, while some have been authenticated, the existence of the others varies according to strains and growth conditions, and their detection fluctuates with the methodologies used for data acquisition and interpretation. For example, several small RNA (sRNA) candidates are now known to be parts of UTR transcripts. Accurate annotation of regulatory RNAs is a complex task essential for molecular and functional studies. We defined bona fide sRNAs as those that (i) likely act in trans and (ii) are not expressed from the opposite strand of a coding gene. Using published data and our own RNA-seq data, we reviewed hundreds of Staphylococcus aureus putative regulatory RNAs using the DETR'PROK computational pipeline and visual inspection of expression data, addressing the question of which transcriptional signals correspond to sRNAs. We conclude that the model strain HG003, a NCTC8325 derivative commonly used for S. aureus genetic regulation studies, has only about 50 bona fide sRNAs, indicating that these RNAs are less numerous than commonly stated. Among them, about half are associated to the S. aureus sp. core genome and a quarter are possibly expressed in other Staphylococci. We hypothesize on their features and regulation using bioinformatic approaches.
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Affiliation(s)
- Wenfeng Liu
- Institute for Integrative Biology of the Cell (I2BC), CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Tatiana Rochat
- VIM, Institut National de la Recherche Agronomique, Université Paris-Saclay, Institut National de la Recherche Agronomique Centre Jouy-en-Josas, Jouy-en-Josas, France
| | - Claire Toffano-Nioche
- Institute for Integrative Biology of the Cell (I2BC), CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Thao Nguyen Le Lam
- Institute for Integrative Biology of the Cell (I2BC), CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Philippe Bouloc
- Institute for Integrative Biology of the Cell (I2BC), CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Claire Morvan
- Institute for Integrative Biology of the Cell (I2BC), CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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26
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Khani A, Popp N, Kreikemeyer B, Patenge N. A Glycine Riboswitch in Streptococcus pyogenes Controls Expression of a Sodium:Alanine Symporter Family Protein Gene. Front Microbiol 2018. [PMID: 29527194 PMCID: PMC5829553 DOI: 10.3389/fmicb.2018.00200] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Regulatory RNAs play important roles in the control of bacterial gene expression. In this study, we investigated gene expression regulation by a putative glycine riboswitch located in the 5'-untranslated region of a sodium:alanine symporter family (SAF) protein gene in the group A Streptococcus pyogenes serotype M49 strain 591. Glycine-dependent gene expression mediated by riboswitch activity was studied using a luciferase reporter gene system. Maximal reporter gene expression was observed in the absence of glycine and in the presence of low glycine concentrations. Differences in glycine-dependent gene expression were not based on differential promoter activity. Expression of the SAF protein gene and the downstream putative cation efflux protein gene was investigated in wild-type bacteria by RT-qPCR transcript analyses. During growth in the presence of glycine (≥1 mM), expression of the genes were downregulated. Northern blot analyses revealed premature transcription termination in the presence of high glycine concentrations. Growth in the presence of 0.1 mM glycine led to the production of a full-length transcript. Furthermore, stability of the SAF protein gene transcript was drastically reduced in the presence of glycine. We conclude that the putative glycine riboswitch in S. pyogenes serotype M49 strain 591 represses expression of the SAF protein gene and the downstream putative cation efflux protein gene in the presence of high glycine concentrations. Sequence and secondary structure comparisons indicated that the streptococcal riboswitch belongs to the class of tandem aptamer glycine riboswitches.
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Affiliation(s)
- Afsaneh Khani
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Nicole Popp
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Nadja Patenge
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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27
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Abstract
Ethanolamine (EA) is a valuable source of carbon and/or nitrogen for bacteria capable of its catabolism. Because it is derived from the membrane phospholipid phosphatidylethanolamine, it is particularly prevalent in the gastrointestinal tract, which is membrane rich due to turnover of the intestinal epithelium and the resident microbiota. Intriguingly, many gut pathogens carry the eut (ethanolamine utilization) genes. EA utilization has been studied for about 50 years, with most of the early work occurring in just a couple of species of Enterobacteriaceae. Once the metabolic pathways and enzymes were characterized by biochemical approaches, genetic screens were used to map the various activities to the eut genes. With the rise of genomics, the diversity of bacteria containing the eut genes and surprising differences in eut gene content were recognized. Some species contain nearly 20 genes and encode many accessory proteins, while others contain only the core catabolic enzyme. Moreover, the eut genes are regulated by very different mechanisms, depending on the organism and the eut regulator encoded. In the last several years, exciting progress has been made in elucidating the complex regulatory mechanisms that govern eut gene expression. Furthermore, a new appreciation for how EA contributes to infection and colonization in the host is emerging. In addition to providing an overview of EA-related biology, this minireview will give special attention to these recent advances.
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28
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Gyulev IS, Willson BJ, Hennessy RC, Krabben P, Jenkinson ER, Thomas GH. Part by Part: Synthetic Biology Parts Used in Solventogenic Clostridia. ACS Synth Biol 2018; 7:311-327. [PMID: 29186949 DOI: 10.1021/acssynbio.7b00327] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solventogenic Clostridia are of interest to the chemical industry because of their natural ability to produce chemicals such as butanol, acetone and ethanol from diverse feedstocks. Their use as whole cell factories presents multiple metabolic engineering targets that could lead to improved sustainability and profitability of Clostridium industrial processes. However, engineering efforts have been held back by the scarcity of genetic and synthetic biology tools. Over the past decade, genetic tools to enable transformation and chromosomal modifications have been developed, but the lack of a broad palette of synthetic biology parts remains one of the last obstacles to the rapid engineered improvement of these species for bioproduction. We have systematically reviewed existing parts that have been used in the modification of solventogenic Clostridia, revealing a narrow range of empirically chosen and nonengineered parts that are in current use. The analysis uncovers elements, such as promoters, transcriptional terminators and ribosome binding sites where increased fundamental knowledge is needed for their reliable use in different applications. Together, the review provides the most comprehensive list of parts used and also presents areas where an improved toolbox is needed for full exploitation of these industrially important bacteria.
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Affiliation(s)
- Ivan S. Gyulev
- Department
of Biology, University of York, Wentworth Way, York YO10 5DD, United Kingdom
| | - Benjamin J. Willson
- Department
of Biology, University of York, Wentworth Way, York YO10 5DD, United Kingdom
| | - Rosanna C. Hennessy
- Department
of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, 1871, Denmark
| | - Preben Krabben
- Green Biologics Limited, Milton Park, Abingdon, Oxfordshire OX14 4RU, United Kingdom
| | | | - Gavin H. Thomas
- Department
of Biology, University of York, Wentworth Way, York YO10 5DD, United Kingdom
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29
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Pintacuda G, Young AN, Cerase A. Function by Structure: Spotlights on Xist Long Non-coding RNA. Front Mol Biosci 2017; 4:90. [PMID: 29302591 PMCID: PMC5742192 DOI: 10.3389/fmolb.2017.00090] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/05/2017] [Indexed: 12/29/2022] Open
Abstract
Recent experimental evidence indicates that lncRNAs can act as regulatory molecules in the context of development and disease. Xist, the master regulator of X chromosome inactivation, is a classic example of how lncRNAs can exert multi-layered and fine-tuned regulatory functions, by acting as a molecular scaffold for recruitment of distinct protein factors. In this review, we discuss the methodologies employed to define Xist RNA structures and the tight interplay between structural clues and functionality of lncRNAs. This model of modular function dictated by structure, can be also generalized to other lncRNAs, beyond the field of X chromosome inactivation, to explain common features of similarly folded RNAs.
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Affiliation(s)
- Greta Pintacuda
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Andrea Cerase
- European Molecular Biology Laboratory, Monterotondo, Italy
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30
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Stamatopoulou V, Apostolidi M, Li S, Lamprinou K, Papakyriakou A, Zhang J, Stathopoulos C. Direct modulation of T-box riboswitch-controlled transcription by protein synthesis inhibitors. Nucleic Acids Res 2017; 45:10242-10258. [PMID: 28973457 PMCID: PMC5622331 DOI: 10.1093/nar/gkx663] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/18/2017] [Indexed: 11/14/2022] Open
Abstract
Recently, it was discovered that exposure to mainstream antibiotics activate numerous bacterial riboregulators that control antibiotic resistance genes including metabolite-binding riboswitches and other transcription attenuators. However, the effects of commonly used antibiotics, many of which exhibit RNA-binding properties, on the widespread T-box riboswitches, remain unknown. In Staphylococcus aureus, a species-specific glyS T-box controls the supply of glycine for both ribosomal translation and cell wall synthesis, making it a promising target for next-generation antimicrobials. Here, we report that specific protein synthesis inhibitors could either significantly increase T-box-mediated transcription antitermination, while other compounds could suppress it, both in vitro and in vivo. In-line probing of the full-length T-box combined with molecular modelling and docking analyses suggest that the antibiotics that promote transcription antitermination stabilize the T-box:tRNA complex through binding specific positions on stem I and the Staphylococcal-specific stem Sa. By contrast, the antibiotics that attenuate T-box transcription bind to other positions on stem I and do not interact with stem Sa. Taken together, our results reveal that the transcription of essential genes controlled by T-box riboswitches can be directly modulated by commonly used protein synthesis inhibitors. These findings accentuate the regulatory complexities of bacterial response to antimicrobials that involve multiple riboregulators.
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Affiliation(s)
| | - Maria Apostolidi
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Shuang Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Bethesda, MD 20892, USA
| | - Katerina Lamprinou
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Athanasios Papakyriakou
- Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos', Athens, Greece
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Bethesda, MD 20892, USA
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31
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Sass A, Kiekens S, Coenye T. Identification of small RNAs abundant in Burkholderia cenocepacia biofilms reveal putative regulators with a potential role in carbon and iron metabolism. Sci Rep 2017; 7:15665. [PMID: 29142288 PMCID: PMC5688073 DOI: 10.1038/s41598-017-15818-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 11/02/2017] [Indexed: 12/23/2022] Open
Abstract
Small RNAs play a regulatory role in many central metabolic processes of bacteria, as well as in developmental processes such as biofilm formation. Small RNAs of Burkholderia cenocepacia, an opportunistic pathogenic beta-proteobacterium, are to date not well characterised. To address that, we performed genome-wide transcriptome structure analysis of biofilm grown B. cenocepacia J2315. 41 unannotated short transcripts were identified in intergenic regions of the B. cenocepacia genome. 15 of these short transcripts, highly abundant in biofilms, widely conserved in Burkholderia sp. and without known function, were selected for in-depth analysis. Expression profiling showed that most of these sRNAs are more abundant in biofilms than in planktonic cultures. Many are also highly abundant in cells grown in minimal media, suggesting they are involved in adaptation to nutrient limitation and growth arrest. Their computationally predicted targets include a high proportion of genes involved in carbon metabolism. Expression and target genes of one sRNA suggest a potential role in regulating iron homoeostasis. The strategy used for this study to detect sRNAs expressed in B. cenocepacia biofilms has successfully identified sRNAs with a regulatory function.
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Affiliation(s)
- Andrea Sass
- Department of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Sanne Kiekens
- Department of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Department of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium.
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Mukherjee S, Barash D, Sengupta S. Comparative genomics and phylogenomic analyses of lysine riboswitch distributions in bacteria. PLoS One 2017; 12:e0184314. [PMID: 28873470 PMCID: PMC5584792 DOI: 10.1371/journal.pone.0184314] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/22/2017] [Indexed: 12/22/2022] Open
Abstract
Riboswitches are cis-regulatory elements that regulate the expression of genes involved in biosynthesis or transport of a ligand that binds to them. Among the nearly 40 classes of riboswitches discovered so far, three are known to regulate the concentration of biologically encoded amino acids glycine, lysine, and glutamine. While some comparative genomics studies of riboswitches focusing on their gross distribution across different bacterial taxa have been carried out recently, systematic functional annotation and analysis of lysine riboswitches and the genes they regulate are still lacking. We analyzed 2785 complete bacterial genome sequences to systematically identify 468 lysine riboswitches (not counting hits from multiple strains of the same species) and obtain a detailed phylogenomic map of gene-specific lysine riboswitch distribution across diverse prokaryotic phyla. We find that lysine riboswitches are most abundant in Firmicutes and Gammaproteobacteria where they are found upstream to both biosynthesis and/or transporter genes. They are relatively rare in all other prokaryotic phyla where if present they are primarily found upstream to operons containing many lysine biosynthesis genes. The genome-wide study of the genetic organisation of the lysine riboswitches show considerable variation both within and across different Firmicute orders. Correlating the location of a riboswitch with its genomic context and its phylogenetic relationship with other evolutionarily related riboswitch carrying species, enables identification and annotation of many lysine biosynthesis, transporter and catabolic genes. It also reveals previously unknown patterns of lysine riboswitch distribution and gene/operon regulation and allows us to draw inferences about the possible point of origin of lysine riboswitches. Additionally, evidence of horizontal transfer of riboswitches was found between Firmicutes and Actinobacteria. Our analysis provides a useful resource that will lead to a better understanding of the evolution of these regulatory elements and prove to be beneficial for exploiting riboswitches for developing targeted therapies.
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Affiliation(s)
- Sumit Mukherjee
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Danny Barash
- Department of Computer Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Supratim Sengupta
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
- * E-mail:
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Abstract
The judicious choice of promoter to drive gene expression remains one of the most important considerations for synthetic biology applications. Constitutive promoter sequences isolated from nature are often used in laboratory settings or small-scale commercial production streams, but unconventional microbial chassis for new synthetic biology applications require well-characterized, robust and orthogonal promoters. This review provides an overview of the opportunities and challenges for synthetic promoter discovery and design, including molecular methodologies, such as saturation mutagenesis of flanking regions and mutagenesis by error-prone PCR, as well as the less familiar use of computational and statistical analyses for de novo promoter design.
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34
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Sedlyarova N, Rescheneder P, Magán A, Popitsch N, Rziha N, Bilusic I, Epshtein V, Zimmermann B, Lybecker M, Sedlyarov V, Schroeder R, Nudler E. Natural RNA Polymerase Aptamers Regulate Transcription in E. coli. Mol Cell 2017; 67:30-43.e6. [PMID: 28648779 PMCID: PMC5535762 DOI: 10.1016/j.molcel.2017.05.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 04/10/2017] [Accepted: 05/23/2017] [Indexed: 01/19/2023]
Abstract
In search for RNA signals that modulate transcription via direct interaction with RNA polymerase (RNAP), we deep sequenced an E. coli genomic library enriched for RNAP-binding RNAs. Many natural RNAP-binding aptamers, termed RAPs, were mapped to the genome. Over 60% of E. coli genes carry RAPs in their mRNA. Combining in vitro and in vivo approaches, we characterized a subset of inhibitory RAPs (iRAPs) that promote Rho-dependent transcription termination. A representative iRAP within the coding region of the essential gene, nadD, greatly reduces its transcriptional output in stationary phase and under oxidative stress, demonstrating that iRAPs control gene expression in response to changing environment. The mechanism of iRAPs involves active uncoupling of transcription and translation, making nascent RNA accessible to Rho. iRAPs encoded in the antisense strand also promote gene expression by reducing transcriptional interference. In essence, our work uncovers a broad class of cis-acting RNA signals that globally control bacterial transcription.
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Affiliation(s)
- Nadezda Sedlyarova
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria
| | - Philipp Rescheneder
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna & Medical University of Vienna, 1030 Vienna, Austria
| | - Andrés Magán
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria
| | - Niko Popitsch
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, 1090 Vienna, Austria
| | - Natascha Rziha
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria
| | - Ivana Bilusic
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Bob Zimmermann
- Department of Molecular Evolution and Development, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Meghan Lybecker
- University of Colorado, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA
| | - Vitaly Sedlyarov
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Renée Schroeder
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria.
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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35
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Abstract
Bacterial pathogens must endure or adapt to different environments and stresses during transmission and infection. Posttranscriptional gene expression control by regulatory RNAs, such as small RNAs and riboswitches, is now considered central to adaptation in many bacteria, including pathogens. The study of RNA-based regulation (riboregulation) in pathogenic species has provided novel insight into how these bacteria regulate virulence gene expression. It has also uncovered diverse mechanisms by which bacterial small RNAs, in general, globally control gene expression. Riboregulators as well as their targets may also prove to be alternative targets or provide new strategies for antimicrobials. In this article, we present an overview of the general mechanisms that bacteria use to regulate with RNA, focusing on examples from pathogens. In addition, we also briefly review how deep sequencing approaches have aided in opening new perspectives in small RNA identification and the study of their functions. Finally, we discuss examples of riboregulators in two model pathogens that control virulence factor expression or survival-associated phenotypes, such as stress tolerance, biofilm formation, or cell-cell communication, to illustrate how riboregulation factors into regulatory networks in bacterial pathogens.
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36
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Villa JK, Amador P, Janovsky J, Bhuyan A, Saldanha R, Lamkin TJ, Contreras LM. A Genome-Wide Search for Ionizing-Radiation-Responsive Elements in Deinococcus radiodurans Reveals a Regulatory Role for the DNA Gyrase Subunit A Gene's 5' Untranslated Region in the Radiation and Desiccation Response. Appl Environ Microbiol 2017; 83:e00039-17. [PMID: 28411225 PMCID: PMC5452802 DOI: 10.1128/aem.00039-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/07/2017] [Indexed: 12/19/2022] Open
Abstract
Tight regulation of gene expression is important for the survival of Deinococcus radiodurans, a model bacterium of extreme stress resistance. Few studies have examined the use of regulatory RNAs as a possible contributing mechanism to ionizing radiation (IR) resistance, despite their proffered efficient and dynamic gene expression regulation under IR stress. This work presents a transcriptome-based approach for the identification of stress-responsive regulatory 5' untranslated region (5'-UTR) elements in D. radiodurans R1 that can be broadly applied to other bacteria. Using this platform and an in vivo fluorescence screen, we uncovered the presence of a radiation-responsive regulatory motif in the 5' UTR of the DNA gyrase subunit A gene. Additional screens under H2O2-induced oxidative stress revealed the specificity of the response of this element to IR stress. Further examination of the sequence revealed a regulatory motif of the radiation and desiccation response (RDR) in the 5' UTR that is necessary for the recovery of D. radiodurans from high doses of IR. Furthermore, we suggest that it is the preservation of predicted RNA structure, in addition to DNA sequence consensus of the motif, that permits this important regulatory ability.IMPORTANCEDeinococcus radiodurans is an extremely stress-resistant bacterium capable of tolerating up to 3,000 times more ionizing radiation than human cells. As an integral part of the stress response mechanism of this organism, we suspect that it maintains stringent control of gene expression. However, understanding of its regulatory pathways remains incomplete to date. Untranslated RNA elements have been demonstrated to play crucial roles in gene regulation throughout bacteria. In this work, we focus on searching for and characterizing responsive RNA elements under radiation stress and propose that multiple levels of gene regulation work simultaneously to enable this organism to efficiently recover from exposure to ionizing radiation. The model we propose serves as a generic template to investigate similar mechanisms of gene regulation under stress that have likely evolved in other bacterial species.
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Affiliation(s)
- Jordan K Villa
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Paul Amador
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Justin Janovsky
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Arijit Bhuyan
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas,USA
| | | | - Thomas J Lamkin
- Air Force Research Laboratory/XPRA Wright-Patterson AFB, Ohio, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas,USA
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37
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Dersch P, Khan MA, Mühlen S, Görke B. Roles of Regulatory RNAs for Antibiotic Resistance in Bacteria and Their Potential Value as Novel Drug Targets. Front Microbiol 2017; 8:803. [PMID: 28529506 PMCID: PMC5418344 DOI: 10.3389/fmicb.2017.00803] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/19/2017] [Indexed: 01/23/2023] Open
Abstract
The emergence of antibiotic resistance mechanisms among bacterial pathogens increases the demand for novel treatment strategies. Lately, the contribution of non-coding RNAs to antibiotic resistance and their potential value as drug targets became evident. RNA attenuator elements in mRNA leader regions couple expression of resistance genes to the presence of the cognate antibiotic. Trans-encoded small RNAs (sRNAs) modulate antibiotic tolerance by base-pairing with mRNAs encoding functions important for resistance such as metabolic enzymes, drug efflux pumps, or transport proteins. Bacteria respond with extensive changes of their sRNA repertoire to antibiotics. Each antibiotic generates a unique sRNA profile possibly causing downstream effects that may help to overcome the antibiotic challenge. In consequence, regulatory RNAs including sRNAs and their protein interaction partners such as Hfq may prove useful as targets for antimicrobial chemotherapy. Indeed, several compounds have been developed that kill bacteria by mimicking ligands for riboswitches controlling essential genes, demonstrating that regulatory RNA elements are druggable targets. Drugs acting on sRNAs are considered for combined therapies to treat infections. In this review, we address how regulatory RNAs respond to and establish resistance to antibiotics in bacteria. Approaches to target RNAs involved in intrinsic antibiotic resistance or virulence for chemotherapy will be discussed.
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Affiliation(s)
- Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Muna A Khan
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
| | - Sabrina Mühlen
- Department of Molecular Infection Biology, Helmholtz Centre for Infection ResearchBraunschweig, Germany
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of ViennaVienna, Austria
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38
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Chen X, Gao C, Guo L, Hu G, Luo Q, Liu J, Nielsen J, Chen J, Liu L. DCEO Biotechnology: Tools To Design, Construct, Evaluate, and Optimize the Metabolic Pathway for Biosynthesis of Chemicals. Chem Rev 2017; 118:4-72. [DOI: 10.1021/acs.chemrev.6b00804] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xiulai Chen
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liang Guo
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Guipeng Hu
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Qiuling Luo
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jia Liu
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jens Nielsen
- Department
of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
- Novo
Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK2800 Lyngby, Denmark
| | - Jian Chen
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- State
Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Department
of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
- Key
Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
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39
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Dual-Targeting Small-Molecule Inhibitors of the Staphylococcus aureus FMN Riboswitch Disrupt Riboflavin Homeostasis in an Infectious Setting. Cell Chem Biol 2017; 24:576-588.e6. [PMID: 28434876 DOI: 10.1016/j.chembiol.2017.03.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/03/2017] [Accepted: 03/23/2017] [Indexed: 11/22/2022]
Abstract
Riboswitches are bacterial-specific, broadly conserved, non-coding RNA structural elements that control gene expression of numerous metabolic pathways and transport functions essential for cell growth. As such, riboswitch inhibitors represent a new class of potential antibacterial agents. Recently, we identified ribocil-C, a highly selective inhibitor of the flavin mononucleotide (FMN) riboswitch that controls expression of de novo riboflavin (RF, vitamin B2) biosynthesis in Escherichia coli. Here, we provide a mechanistic characterization of the antibacterial effects of ribocil-C as well as of roseoflavin (RoF), an antimetabolite analog of RF, among medically significant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis. We provide genetic, biophysical, computational, biochemical, and pharmacological evidence that ribocil-C and RoF specifically inhibit dual FMN riboswitches, separately controlling RF biosynthesis and uptake processes essential for MRSA growth and pathogenesis. Such a dual-targeting mechanism is specifically required to develop broad-spectrum Gram-positive antibacterial agents targeting RF metabolism.
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40
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Li C, Lv D, Zhang L, Yang F, Wang C, Su J, Zhang Y. Approach to the unfolding and folding dynamics of add A-riboswitch upon adenine dissociation using a coarse-grained elastic network model. J Chem Phys 2017; 145:014104. [PMID: 27394096 DOI: 10.1063/1.4954992] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Riboswitches are noncoding mRNA segments that can regulate the gene expression via altering their structures in response to specific metabolite binding. We proposed a coarse-grained Gaussian network model (GNM) to examine the unfolding and folding dynamics of adenosine deaminase (add) A-riboswitch upon the adenine dissociation, in which the RNA is modeled by a nucleotide chain with interaction networks formed by connecting adjoining atomic contacts. It was shown that the adenine binding is critical to the folding of the add A-riboswitch while the removal of the ligand can result in drastic increase of the thermodynamic fluctuations especially in the junction regions between helix domains. Under the assumption that the native contacts with the highest thermodynamic fluctuations break first, the iterative GNM simulations showed that the unfolding process of the adenine-free add A-riboswitch starts with the denature of the terminal helix stem, followed by the loops and junctions involving ligand binding pocket, and then the central helix domains. Despite the simplified coarse-grained modeling, the unfolding dynamics and pathways are shown in close agreement with the results from atomic-level MD simulations and the NMR and single-molecule force spectroscopy experiments. Overall, the study demonstrates a new avenue to investigate the binding and folding dynamics of add A-riboswitch molecule which can be readily extended for other RNA molecules.
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Affiliation(s)
- Chunhua Li
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Dashuai Lv
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Lei Zhang
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Feng Yang
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Cunxin Wang
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Jiguo Su
- College of Science, Yanshan University, Qinhuangdao 066004, China
| | - Yang Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 45108, USA
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41
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New RNA-seq approaches for the study of bacterial pathogens. Curr Opin Microbiol 2017; 35:78-87. [DOI: 10.1016/j.mib.2017.01.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 12/17/2022]
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42
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Sedlyarova N, Shamovsky I, Bharati BK, Epshtein V, Chen J, Gottesman S, Schroeder R, Nudler E. sRNA-Mediated Control of Transcription Termination in E. coli. Cell 2016; 167:111-121.e13. [PMID: 27662085 DOI: 10.1016/j.cell.2016.09.004] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Accepted: 09/01/2016] [Indexed: 12/16/2022]
Abstract
Bacterial small RNAs (sRNAs) have been implicated in various aspects of post-transcriptional gene regulation. Here, we demonstrate that sRNAs also act at the level of transcription termination. We use the rpoS gene, which encodes a general stress sigma factor σ(S), as a model system, and show that sRNAs DsrA, ArcZ, and RprA bind the rpoS 5'UTR to suppress premature Rho-dependent transcription termination, both in vitro and in vivo. sRNA-mediated antitermination markedly stimulates transcription of rpoS during the transition to the stationary phase of growth, thereby facilitating a rapid adjustment of bacteria to global metabolic changes. Next generation RNA sequencing and bioinformatic analysis indicate that Rho functions as a global "attenuator" of transcription, acting at the 5'UTR of hundreds of bacterial genes, and that its suppression by sRNAs is a widespread mode of bacterial gene regulation.
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Affiliation(s)
- Nadezda Sedlyarova
- Department of Biochemistry and Cellbiology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ilya Shamovsky
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Binod K Bharati
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Jiandong Chen
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Renée Schroeder
- Department of Biochemistry and Cellbiology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, 1030 Vienna, Austria
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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43
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Mg2+-dependent translational speed bump acts to regulate gene transcription. Proc Natl Acad Sci U S A 2016; 113:14881-14883. [PMID: 27994154 DOI: 10.1073/pnas.1618222114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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44
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Noro E, Mori M, Makino G, Takai Y, Ohnuma S, Sato A, Tomita M, Nakahigashi K, Kanai A. Systematic characterization of artificial small RNA-mediated inhibition of Escherichia coli growth. RNA Biol 2016; 14:206-218. [PMID: 27981881 PMCID: PMC5324740 DOI: 10.1080/15476286.2016.1270001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A new screening system for artificial small RNAs (sRNAs) that inhibit the growth of Escherichia coli was constructed. In this system, we used a plasmid library to express RNAs of ∼120 nucleotides, each with a random 30-nucleotide sequence that can recognize its target mRNA(s). After approximately 60,000 independent colonies were screened, several plasmids that inhibited bacterial growth were isolated. To understand the inhibitory mechanism, we focused on one sRNA, S-20, that exerted a strong inhibitory effect. A time-course analysis of the proteome of S-20-expressing E. coli and a bioinformatic analysis were used to identify potential S-20 target mRNAs, and suggested that S-20 binds the translation initiation sites of several mRNAs encoding enzymes such as peroxiredoxin (osmC), glycyl-tRNA synthetase α subunit (glyQ), uncharacterized protein ygiM, and tryptophan synthase β chain (trpB). An in vitro translation analysis of chimeric luciferase-encoding mRNAs, each containing a potential S-20 target sequence, indicated that the translation of these mRNAs was inhibited in the presence of S-20. A gel shift analysis combined with the analysis of a series of S-20 mutants suggested that S-20 targets multiple mRNAs that are responsible for inhibiting E. coli growth. These data also suggest that S-20 acts like an endogenous sRNA and that E. coli can utilize artificial sRNAs.
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Affiliation(s)
- Emiko Noro
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan
| | - Masaru Mori
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan.,b Systems Biology Program, Graduate School of Media and Governance, Keio University , Fujisawa , Japan
| | - Gakuto Makino
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan.,c Faculty of Environment and Information Studies, Keio University , Fujisawa , Japan
| | - Yuki Takai
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan
| | - Sumiko Ohnuma
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan
| | - Asako Sato
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan
| | - Masaru Tomita
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan.,b Systems Biology Program, Graduate School of Media and Governance, Keio University , Fujisawa , Japan.,c Faculty of Environment and Information Studies, Keio University , Fujisawa , Japan
| | - Kenji Nakahigashi
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan.,b Systems Biology Program, Graduate School of Media and Governance, Keio University , Fujisawa , Japan
| | - Akio Kanai
- a Institute for Advanced Biosciences, Keio University , Tsuruoka , Japan.,b Systems Biology Program, Graduate School of Media and Governance, Keio University , Fujisawa , Japan.,c Faculty of Environment and Information Studies, Keio University , Fujisawa , Japan
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Abstract
Small regulatory RNAs comprise critically important modulators of gene expression in bacteria, yet very little is known about their prevalence and functions in Rickettsia species. R. conorii, the causative agent of Mediterranean spotted fever, is a tick-borne pathogen that primarily infects microvascular endothelium in humans. We have determined the transcriptional landscape of R. conorii during infection of Human Microvascular Endothelial Cells (HMECs) by strand-specific RNA sequencing to identify 4 riboswitches, 13 trans-acting (intergenic), and 22 cis-acting (antisense) small RNAs (termed ‘Rc_sR’s). Independent expression of four novel trans-acting sRNAs (Rc_sR31, Rc_sR33, Rc_sR35, and Rc_sR42) and known bacterial sRNAs (6S, RNaseP_bact_a, ffs, and α-tmRNA) was next confirmed by Northern hybridization. Comparative analysis during infection of HMECs vis-à-vis tick AAE2 cells revealed significantly higher expression of Rc_sR35 and Rc_sR42 in HMECs, whereas Rc_sR31 and Rc_sR33 were expressed at similar levels in both cell types. We further predicted a total of 502 genes involved in all important biological processes as potential targets of Rc_sRs and validated the interaction of Rc_sR42 with cydA (cytochrome d ubiquinol oxidase subunit I). Our findings constitute the first evidence of the existence of post-transcriptional riboregulatory mechanisms in R. conorii and interactions between a novel Rc_sR and its target mRNA.
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46
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Qian S, Cirino PC. Using metabolite-responsive gene regulators to improve microbial biosynthesis. Curr Opin Chem Eng 2016. [DOI: 10.1016/j.coche.2016.08.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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47
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Slinger BL, Meyer MM. RNA regulators responding to ribosomal protein S15 are frequent in sequence space. Nucleic Acids Res 2016; 44:9331-9341. [PMID: 27580716 PMCID: PMC5100602 DOI: 10.1093/nar/gkw754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/19/2016] [Indexed: 02/07/2023] Open
Abstract
There are several natural examples of distinct RNA structures that interact with the same ligand to regulate the expression of homologous genes in different organisms. One essential question regarding this phenomenon is whether such RNA regulators are the result of convergent or divergent evolution. Are the RNAs derived from some common ancestor and diverged to the point where we cannot identify the similarity, or have multiple solutions to the same biological problem arisen independently? A key variable in assessing these alternatives is how frequently such regulators arise within sequence space. Ribosomal protein S15 is autogenously regulated via an RNA regulator in many bacterial species; four apparently distinct regulators have been functionally validated in different bacterial phyla. Here, we explore how frequently such regulators arise within a partially randomized sequence population. We find many RNAs that interact specifically with ribosomal protein S15 from Geobacillus kaustophilus with biologically relevant dissociation constants. Furthermore, of the six sequences we characterize, four show regulatory activity in an Escherichia coli reporter assay. Subsequent footprinting and mutagenesis analysis indicates that protein binding proximal to regulatory features such as the Shine–Dalgarno sequence is sufficient to enable regulation, suggesting that regulation in response to S15 is relatively easily acquired.
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Affiliation(s)
- Betty L Slinger
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| | - Michelle M Meyer
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
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48
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Dar D, Prasse D, Schmitz RA, Sorek R. Widespread formation of alternative 3′ UTR isoforms via transcription termination in archaea. Nat Microbiol 2016; 1:16143. [DOI: 10.1038/nmicrobiol.2016.143] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/14/2016] [Indexed: 12/12/2022]
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49
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Howe JA, Xiao L, Fischmann TO, Wang H, Tang H, Villafania A, Zhang R, Barbieri CM, Roemer T. Atomic resolution mechanistic studies of ribocil: A highly selective unnatural ligand mimic of the E. coli FMN riboswitch. RNA Biol 2016; 13:946-954. [PMID: 27485612 PMCID: PMC5056776 DOI: 10.1080/15476286.2016.1216304] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Bacterial riboswitches are non-coding RNA structural elements that direct gene expression in numerous metabolic pathways. The key regulatory roles of riboswitches, and the urgent need for new classes of antibiotics to treat multi-drug resistant bacteria, has led to efforts to develop small-molecules that mimic natural riboswitch ligands to inhibit metabolic pathways and bacterial growth. Recently, we reported the results of a phenotypic screen targeting the riboflavin biosynthesis pathway in the Gram-negative bacteria Escherichia coli that led to the identification of ribocil, a small molecule inhibitor of the flavin mononucleotide (FMN) riboswitch controlling expression of this biosynthetic pathway. Although ribocil is structurally distinct from FMN, ribocil functions as a potent and highly selective synthetic mimic of the natural ligand to repress riboswitch-mediated ribB gene expression and inhibit bacterial growth both in vitro and in vivo. Herein, we expand our analysis of ribocil; including mode of binding in the FMN binding pocket of the riboswitch, mechanisms of resistance and structure-activity relationship guided efforts to generate more potent analogs.
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Affiliation(s)
- John A Howe
- a Merck Research Laboratories , Kenilworth , NJ , USA
| | - Li Xiao
- a Merck Research Laboratories , Kenilworth , NJ , USA
| | | | - Hao Wang
- a Merck Research Laboratories , Kenilworth , NJ , USA
| | - Haifeng Tang
- a Merck Research Laboratories , Kenilworth , NJ , USA
| | | | - Rumin Zhang
- a Merck Research Laboratories , Kenilworth , NJ , USA
| | | | - Terry Roemer
- a Merck Research Laboratories , Kenilworth , NJ , USA
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50
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Abstract
Enteric pathogens of the family Enterobacteriaceae colonize various niches within animals and humans in which they compete with intestinal commensals and are attacked by the host immune system. To survive these hostile environments they possess complex, multilayer regulatory networks that coordinate the control of virulence factors, host-adapted metabolic functions and stress resistance. An important part of these intricate control networks are RNA-based control systems that enable the pathogen to fine-tune its responses. Recent next-generation sequencing approaches revealed a large repertoire of conserved and species-specific riboregulators, including numerous cis- and trans-acting non-coding RNAs, sensory RNA elements (RNA thermometers, riboswitches), regulatory RNA-binding proteins and RNA degrading enzymes which regulate colonization factors, toxins, host defense processes and virulence-relevant physiological and metabolic processes. All of which are important cues for pathogens to sense and respond to fluctuating conditions during the infection. This review covers infection-relevant riboregulators of E. coli, Salmonella, Shigella and Yersinia, highlights their versatile regulatory mechanisms, complex target regulons and functions, and discusses emerging topics and future challenges to fully understand and exploit RNA-based control to combat bacterial infections.
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Affiliation(s)
- Ann Kathrin Heroven
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
| | - Aaron M Nuss
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
| | - Petra Dersch
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
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