1
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Developing New Tools to Fight Human Pathogens: A Journey through the Advances in RNA Technologies. Microorganisms 2022; 10:microorganisms10112303. [DOI: 10.3390/microorganisms10112303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/12/2022] [Accepted: 11/15/2022] [Indexed: 11/22/2022] Open
Abstract
A long scientific journey has led to prominent technological advances in the RNA field, and several new types of molecules have been discovered, from non-coding RNAs (ncRNAs) to riboswitches, small interfering RNAs (siRNAs) and CRISPR systems. Such findings, together with the recognition of the advantages of RNA in terms of its functional performance, have attracted the attention of synthetic biologists to create potent RNA-based tools for biotechnological and medical applications. In this review, we have gathered the knowledge on the connection between RNA metabolism and pathogenesis in Gram-positive and Gram-negative bacteria. We further discuss how RNA techniques have contributed to the building of this knowledge and the development of new tools in synthetic biology for the diagnosis and treatment of diseases caused by pathogenic microorganisms. Infectious diseases are still a world-leading cause of death and morbidity, and RNA-based therapeutics have arisen as an alternative way to achieve success. There are still obstacles to overcome in its application, but much progress has been made in a fast and effective manner, paving the way for the solid establishment of RNA-based therapies in the future.
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2
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Romero J, Islam MT, Taylor R, Grayson C, Schoenrock A, Wong A. High-throughput design of bacterial anti-sense RNAs using CAREng. BIOINFORMATICS ADVANCES 2022; 2:vbac069. [PMID: 36699397 PMCID: PMC9710602 DOI: 10.1093/bioadv/vbac069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/19/2022] [Accepted: 09/23/2022] [Indexed: 01/28/2023]
Abstract
Summary Short RNA (sRNA) modulation of gene expression is an increasingly popular tool for bacterial functional genomics. Antisense pairing between an sRNA and a target messenger RNA results in post-transcriptional down-regulation of a specific gene and can thus be used both for investigating individual gene function and for large-scale genetic screens. sRNAs have several advantages over knockout libraries in studies of gene function, including inducibility, the capacity to interrogate essential genes and easy portability to multiple genetic backgrounds. High-throughput, systematic design of antisense RNAs will increase the efficiency and repeatability of sRNA screens. To this end, we present CAREng, the Computer-Automated sRNA Engineer. CAREng designs antisense RNAs for all coding sequences in a given genome, while checking for potential off-targets. Availability and implementation CAREng is available as a Python script and through a web portal (https://caren.carleton.ca). Supplementary information Supplementary data are available at Bioinformatics Advances online.
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Affiliation(s)
- Jazmin Romero
- Research Computing Services, Carleton University, Ottawa K1S 5B6, Canada
| | - Md Tanvir Islam
- Research Computing Services, Carleton University, Ottawa K1S 5B6, Canada
| | - Ryan Taylor
- Research Computing Services, Carleton University, Ottawa K1S 5B6, Canada
| | - Cathryn Grayson
- Department of Biology, Carleton University, Ottawa K1S 5B6, Canada
| | - Andrew Schoenrock
- Research Computing Services, Carleton University, Ottawa K1S 5B6, Canada
| | - Alex Wong
- To whom correspondence should be addressed.
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3
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Köbel T, Melo Palhares R, Fromm C, Szymanski W, Angelidou G, Glatter T, Georg J, Berghoff BA, Schindler D. An Easy-to-Use Plasmid Toolset for Efficient Generation and Benchmarking of Synthetic Small RNAs in Bacteria. ACS Synth Biol 2022; 11:2989-3003. [PMID: 36044590 PMCID: PMC9486967 DOI: 10.1021/acssynbio.2c00164] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synthetic biology approaches life from the perspective of an engineer. Standardized and de novo design of genetic parts to subsequently build reproducible and controllable modules, for example, for circuit design, is a key element. To achieve this, natural systems and elements often serve as a blueprint for researchers. Regulation of protein abundance is controlled at DNA, mRNA, and protein levels. Many tools for the activation or repression of transcription or the destabilization of proteins are available, but easy-to-handle minimal regulatory elements on the mRNA level are preferable when translation needs to be modulated. Regulatory RNAs contribute considerably to regulatory networks in all domains of life. In particular, bacteria use small regulatory RNAs (sRNAs) to regulate mRNA translation. Slowly, sRNAs are attracting the interest of using them for broad applications in synthetic biology. Here, we promote a "plug and play" plasmid toolset to quickly and efficiently create synthetic sRNAs to study sRNA biology or their application in bacteria. We propose a simple benchmarking assay by targeting the acrA gene of Escherichia coli and rendering cells sensitive toward the β-lactam antibiotic oxacillin. We further highlight that it may be necessary to test multiple seed regions and sRNA scaffolds to achieve the desired regulatory effect. The described plasmid toolset allows quick construction and testing of various synthetic sRNAs based on the user's needs.
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Affiliation(s)
- Tania
S. Köbel
- RG
Schindler, Max-Planck-Institute for Terrestrial
Microbiology, Karl-von-Frisch-Street
10, 35043 Marburg, Germany,MaxGENESYS
Biofoundry, Max-Planck-Institute for Terrestrial
Microbiology, Karl-von-Frisch-Street
10, 35043 Marburg, Germany
| | - Rafael Melo Palhares
- RG
Schindler, Max-Planck-Institute for Terrestrial
Microbiology, Karl-von-Frisch-Street
10, 35043 Marburg, Germany,Institute
for Microbiology and Molecular Biology, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Christin Fromm
- Institute
for Microbiology and Molecular Biology, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Witold Szymanski
- Mass
Spectrometry and Proteomics Core Facility, Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Street 10, 35043 Marburg, Germany
| | - Georgia Angelidou
- Mass
Spectrometry and Proteomics Core Facility, Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Street 10, 35043 Marburg, Germany
| | - Timo Glatter
- Mass
Spectrometry and Proteomics Core Facility, Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Street 10, 35043 Marburg, Germany
| | - Jens Georg
- Institut
für Biologie III, Albert-Ludwigs-Universität
Freiburg, Schänzlestraße
1, 79104 Freiburg, Germany
| | - Bork A. Berghoff
- Institute
for Microbiology and Molecular Biology, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany,
| | - Daniel Schindler
- RG
Schindler, Max-Planck-Institute for Terrestrial
Microbiology, Karl-von-Frisch-Street
10, 35043 Marburg, Germany,MaxGENESYS
Biofoundry, Max-Planck-Institute for Terrestrial
Microbiology, Karl-von-Frisch-Street
10, 35043 Marburg, Germany,
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4
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Han Y, Li C, Yan Y, Lin M, Ke X, Zhang Y, Zhan Y. Post-transcriptional control of bacterial nitrogen metabolism by regulatory noncoding RNAs. World J Microbiol Biotechnol 2022; 38:126. [PMID: 35666348 PMCID: PMC9170634 DOI: 10.1007/s11274-022-03287-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/12/2022] [Indexed: 12/04/2022]
Abstract
Nitrogen metabolism is the most basic process of material and energy metabolism in living organisms, and processes involving the uptake and use of different nitrogen sources are usually tightly regulated at the transcriptional and post-transcriptional levels. Bacterial regulatory noncoding RNAs are novel post-transcriptional regulators that repress or activate the expression of target genes through complementarily pairing with target mRNAs; therefore, these noncoding RNAs play an important regulatory role in many physiological processes, such as bacterial substance metabolism and stress response. In recent years, a study found that noncoding RNAs play a vital role in the post-transcriptional regulation of nitrogen metabolism, which is currently a hot topic in the study of bacterial nitrogen metabolism regulation. In this review, we present an overview of recent advances that increase our understanding on the regulatory roles of bacterial noncoding RNAs and describe in detail how noncoding RNAs regulate biological nitrogen fixation and nitrogen metabolic engineering. Furthermore, our goal is to lay a theoretical foundation for better understanding the molecular mechanisms in bacteria that are involved in environmental adaptations and metabolically-engineered genetic modifications.
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Affiliation(s)
- Yueyue Han
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chao Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongliang Yan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Min Lin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiubin Ke
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yunhua Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China. .,School of Resources and Environment, Anhui Agricultural University, Hefei, China.
| | - Yuhua Zhan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
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5
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Li Y, Mensah EO, Fordjour E, Bai J, Yang Y, Bai Z. Recent advances in high-throughput metabolic engineering: Generation of oligonucleotide-mediated genetic libraries. Biotechnol Adv 2022; 59:107970. [PMID: 35550915 DOI: 10.1016/j.biotechadv.2022.107970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 04/05/2022] [Accepted: 05/04/2022] [Indexed: 02/07/2023]
Abstract
The preparation of genetic libraries is an essential step to evolve microorganisms and study genotype-phenotype relationships by high-throughput screening/selection. As the large-scale synthesis of oligonucleotides becomes easy, cheap, and high-throughput, numerous novel strategies have been developed in recent years to construct high-quality oligo-mediated libraries, leveraging state-of-art molecular biology tools for genome editing and gene regulation. This review presents an overview of recent advances in creating and characterizing in vitro and in vivo genetic libraries, based on CRISPR/Cas, regulatory RNAs, and recombineering, primarily for Escherichia coli and Saccharomyces cerevisiae. These libraries' applications in high-throughput metabolic engineering, strain evolution and protein engineering are also discussed.
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Affiliation(s)
- Ye Li
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, Wuxi 214122, China.
| | - Emmanuel Osei Mensah
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Eric Fordjour
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jing Bai
- School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Yankun Yang
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhonghu Bai
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, Wuxi 214122, China.
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6
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Dwijayanti A, Storch M, Stan GB, Baldwin GS. A modular RNA interference system for multiplexed gene regulation. Nucleic Acids Res 2022; 50:1783-1793. [PMID: 35061908 PMCID: PMC8860615 DOI: 10.1093/nar/gkab1301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
The rational design and realisation of simple-to-use genetic control elements that are modular, orthogonal and robust is essential to the construction of predictable and reliable biological systems of increasing complexity. To this effect, we introduce modular Artificial RNA interference (mARi), a rational, modular and extensible design framework that enables robust, portable and multiplexed post-transcriptional regulation of gene expression in Escherichia coli. The regulatory function of mARi was characterised in a range of relevant genetic contexts, demonstrating its independence from other genetic control elements and the gene of interest, and providing new insight into the design rules of RNA based regulation in E. coli, while a range of cellular contexts also demonstrated it to be independent of growth-phase and strain type. Importantly, the extensibility and orthogonality of mARi enables the simultaneous post-transcriptional regulation of multi-gene systems as both single-gene cassettes and poly-cistronic operons. To facilitate adoption, mARi was designed to be directly integrated into the modular BASIC DNA assembly framework. We anticipate that mARi-based genetic control within an extensible DNA assembly framework will facilitate metabolic engineering, layered genetic control, and advanced genetic circuit applications.
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Affiliation(s)
| | - Marko Storch
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.,Department of Bioengineering, Bessemer Building, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - Geoff S Baldwin
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
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7
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Roux C, Etienne TA, Hajnsdorf E, Ropers D, Carpousis AJ, Cocaign-Bousquet M, Girbal L. The essential role of mRNA degradation in understanding and engineering E. coli metabolism. Biotechnol Adv 2021; 54:107805. [PMID: 34302931 DOI: 10.1016/j.biotechadv.2021.107805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 06/28/2021] [Accepted: 07/14/2021] [Indexed: 11/17/2022]
Abstract
Metabolic engineering strategies are crucial for the development of bacterial cell factories with improved performance. Until now, optimal metabolic networks have been designed based on systems biology approaches integrating large-scale data on the steady-state concentrations of mRNA, protein and metabolites, sometimes with dynamic data on fluxes, but rarely with any information on mRNA degradation. In this review, we compile growing evidence that mRNA degradation is a key regulatory level in E. coli that metabolic engineering strategies should take into account. We first discuss how mRNA degradation interacts with transcription and translation, two other gene expression processes, to balance transcription regulation and remove poorly translated mRNAs. The many reciprocal interactions between mRNA degradation and metabolism are also highlighted: metabolic activity can be controlled by changes in mRNA degradation and in return, the activity of the mRNA degradation machinery is controlled by metabolic factors. The mathematical models of the crosstalk between mRNA degradation dynamics and other cellular processes are presented and discussed with a view towards novel mRNA degradation-based metabolic engineering strategies. We show finally that mRNA degradation-based strategies have already successfully been applied to improve heterologous protein synthesis. Overall, this review underlines how important mRNA degradation is in regulating E. coli metabolism and identifies mRNA degradation as a key target for innovative metabolic engineering strategies in biotechnology.
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Affiliation(s)
- Charlotte Roux
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France; UMR8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Thibault A Etienne
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France; Univ. Grenoble Alpes, Inria, 38000 Grenoble, France.
| | - Eliane Hajnsdorf
- UMR8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | | | - A J Carpousis
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France; LMGM, Université de Toulouse, CNRS, UPS, CBI, 31062 Toulouse, France.
| | | | - Laurence Girbal
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France.
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8
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Recent advances in tuning the expression and regulation of genes for constructing microbial cell factories. Biotechnol Adv 2021; 50:107767. [PMID: 33974979 DOI: 10.1016/j.biotechadv.2021.107767] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/29/2021] [Accepted: 05/05/2021] [Indexed: 12/14/2022]
Abstract
To overcome environmental problems caused by the use of fossil resources, microbial cell factories have become a promising technique for the sustainable and eco-friendly development of valuable products from renewable resources. Constructing microbial cell factories with high titers, yields, and productivity requires a balance between growth and production; to this end, tuning gene expression and regulation is necessary to optimise and precisely control complicated metabolic fluxes. In this article, we review the current trends and advances in tuning gene expression and regulation and consider their engineering at each of the three stages of gene regulation: genomic, mRNA, and protein. In particular, the technological approaches utilised in a diverse range of genetic-engineering-based tools for the construction of microbial cell factories are reviewed and representative applications of these strategies are presented. Finally, the prospects for strategies and systems for tuning gene expression and regulation are discussed.
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9
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Bak G, Choi JS, Kim W, Suk S, Lee Y. An Effective Method for Specific Gene Silencing in Escherichia coli Using Artificial Small RNA. Methods Mol Biol 2021; 2323:233-247. [PMID: 34086285 DOI: 10.1007/978-1-0716-1499-0_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Knockdown or silencing of a specific gene presents a powerful strategy for elucidating gene function in a variety of organisms. To date, efficient silencing methods have been established in eukaryotes, but not bacteria. In this chapter, an efficient and versatile gene silencing method using artificial small RNA (afsRNA) is described. For this purpose, target-recognizing sequences were introduced in specially designed RNA scaffolds to exist as single-stranded stretches in afsRNA. The translation initiation region of target genes was used as the sequence for afsRNA recognition, based on the theory that this site is usually highly accessible to ribosomes, and therefore, possibly, afsRNA. Two genes transcribed as monocistrons were tested with our protocol. Both genes were effectively silenced by their cognate afsRNAs.
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Affiliation(s)
- Geunu Bak
- Department of Chemistry, KAIST , Daejeon, South Korea
| | - Jee Soo Choi
- Department of Chemistry, KAIST , Daejeon, South Korea
| | - Wonkyeong Kim
- Department of Chemistry, KAIST , Daejeon, South Korea
| | - Shinae Suk
- Department of Chemistry, KAIST , Daejeon, South Korea
| | - Younghoon Lee
- Department of Chemistry, KAIST , Daejeon, South Korea.
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10
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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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11
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Van Brempt M, Clauwaert J, Mey F, Stock M, Maertens J, Waegeman W, De Mey M. Predictive design of sigma factor-specific promoters. Nat Commun 2020; 11:5822. [PMID: 33199691 PMCID: PMC7670410 DOI: 10.1038/s41467-020-19446-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
To engineer synthetic gene circuits, molecular building blocks are developed which can modulate gene expression without interference, mutually or with the host's cell machinery. As the complexity of gene circuits increases, automated design tools and tailored building blocks to ensure perfect tuning of all components in the network are required. Despite the efforts to develop prediction tools that allow forward engineering of promoter transcription initiation frequency (TIF), such a tool is still lacking. Here, we use promoter libraries of E. coli sigma factor 70 (σ70)- and B. subtilis σB-, σF- and σW-dependent promoters to construct prediction models, capable of both predicting promoter TIF and orthogonality of the σ-specific promoters. This is achieved by training a convolutional neural network with high-throughput DNA sequencing data from fluorescence-activated cell sorted promoter libraries. This model functions as the base of the online promoter design tool (ProD), providing tailored promoters for tailored genetic systems.
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Affiliation(s)
- Maarten Van Brempt
- Centre for Synthetic Biology (CSB), Department of Biotechnology, Ghent University, 9000, Ghent, Belgium
| | - Jim Clauwaert
- KERMIT, Department of Data Analysis and Mathematical Modelling, Ghent University, 9000, Ghent, Belgium
| | - Friederike Mey
- Centre for Synthetic Biology (CSB), Department of Biotechnology, Ghent University, 9000, Ghent, Belgium
| | - Michiel Stock
- KERMIT, Department of Data Analysis and Mathematical Modelling, Ghent University, 9000, Ghent, Belgium
| | - Jo Maertens
- Centre for Synthetic Biology (CSB), Department of Biotechnology, Ghent University, 9000, Ghent, Belgium
| | - Willem Waegeman
- KERMIT, Department of Data Analysis and Mathematical Modelling, Ghent University, 9000, Ghent, Belgium
| | - Marjan De Mey
- Centre for Synthetic Biology (CSB), Department of Biotechnology, Ghent University, 9000, Ghent, Belgium.
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12
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Apura P, Saramago M, Peregrina A, Viegas SC, Carvalho SM, Saraiva LM, Arraiano CM, Domingues S. Tailor-made sRNAs: a plasmid tool to control the expression of target mRNAs in Pseudomonas putida. Plasmid 2020; 109:102503. [PMID: 32209400 DOI: 10.1016/j.plasmid.2020.102503] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/02/2020] [Accepted: 03/06/2020] [Indexed: 11/25/2022]
Abstract
Pseudomonas putida is a highly attractive production system for industrial needs. However, for its improvement as a biocatalyst at the industrial level, modulation of its gene expression is urgently needed. We report the construction of a plasmid expressing a small RNA-based system with the potential to be used for different purposes. Due to the small RNAs modular composition, the design facilities and ability to tune gene expression, they constitute a powerful tool in genetic and metabolic engineering. In the tool presented here, customized sRNAs are expressed from a plasmid and specifically directed to any region of a chosen target. Expression of these customized sRNAs is shown to differentially modulate the level of endogenous and heterologous reporter genes. The antisense interaction of the sRNA with the mRNA produces different outcomes. Depending on the particularity of each sRNA-target mRNA pair, we demonstrate the duality of this system, which is able either to decrease or increase the expression of the same given gene. This system combines high specificity with the potential to be widely applied, due to its predicted ability to modulate the expression of virtually any given gene. This plasmid can be used to redesign P. putida metabolism, fulfilling an important industrial gap.
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Affiliation(s)
- Patrícia Apura
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Margarida Saramago
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Alexandra Peregrina
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sandra C Viegas
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
| | - Sandra M Carvalho
- Molecular Mechanisms of Pathogen Resistance Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Lígia M Saraiva
- Molecular Mechanisms of Pathogen Resistance Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Cecília M Arraiano
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
| | - Susana Domingues
- Control of Gene Expression Lab, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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13
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Abstract
In light of the rising prevalence of antimicrobial resistance (AMR) and the slow pace of new antimicrobial development, there has been increasing interest in the development of adjuvants that improve or restore the effectiveness of existing drugs. Here, we use a novel small RNA (sRNA) screening approach to identify genes whose knockdown increases ciprofloxacin (CIP) sensitivity in a resistant strain of Escherichia coli 5000 sRNA constructs were initially screened on a gyrA S83L background, ultimately leading to 30 validated genes whose disruption reduces CIP resistance. This set includes genes involved in DNA replication, repair, recombination, efflux, and other regulatory systems. Our findings increase understanding of the functional interactions of DNA Gyrase, and may aid in the development of new therapeutic approaches for combating AMR.
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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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Advances in engineered trans-acting regulatory RNAs and their application in bacterial genome engineering. J Ind Microbiol Biotechnol 2019; 46:819-830. [PMID: 30887255 DOI: 10.1007/s10295-019-02160-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 03/05/2019] [Indexed: 12/15/2022]
Abstract
Small noncoding RNAs, a large class of ancient posttranscriptional regulators, are increasingly recognized and utilized as key modulators of gene expression in a broad range of microorganisms. Owing to their small molecular size and the central role of Watson-Crick base pairing in defining their interactions, structure and function, numerous diverse types of trans-acting RNA regulators that are functional at the DNA, mRNA and protein levels have been experimentally characterized. It has become increasingly clear that most small RNAs play critical regulatory roles in many processes and are, therefore, considered to be powerful tools for genetic engineering and synthetic biology. The trans-acting regulatory RNAs accelerate this ability to establish potential framework for genetic engineering and genome-scale engineering, which allows RNA structure characterization, easier to design and model compared to DNA or protein-based systems. In this review, we summarize recent advances in engineered trans-acting regulatory RNAs that are used in bacterial genome-scale engineering and in novel cellular capabilities as well as their implementation in wide range of biotechnological, biological and medical applications.
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16
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Dwidar M, Yokobayashi Y. Riboswitch Signal Amplification by Controlling Plasmid Copy Number. ACS Synth Biol 2019; 8:245-250. [PMID: 30682247 DOI: 10.1021/acssynbio.8b00454] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Riboswitches are cis-acting RNA devices in mRNAs that control gene expression in response to chemical inputs. As RNA aptamers that recognize diverse classes of molecules can be isolated by in vitro selection, synthetic riboswitches hold promise for various applications in synthetic biology. One of the major drawbacks of riboswitches, however, is their limited dynamic range. A high level of gene expression in the OFF state (leakage) is also a common problem. To address these challenges, we designed and constructed a dual-riboswitch plasmid in which two genes are controlled by theophylline-activated riboswitches. One riboswitch controls the gene of interest, and another riboswitch controls RepL, a phage-derived replication protein that regulates the plasmid copy number. This single-plasmid system afforded an ON/OFF ratio as high as 3900. Furthermore, we used the system to control CRISPR interference (CRISPRi) targeting endogenous genes, and successfully observed expected phenotypic changes in Escherichia coli.
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Affiliation(s)
- Mohammed Dwidar
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904 0495, Japan
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17
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Norouzi M, Pickford AR, Butt LE, Vincent HA, Callaghan AJ. Application of mRNA Arrays for the Production of mCherry Reporter-Protein Arrays for Quantitative Gene Expression Analysis. ACS Synth Biol 2019; 8:207-215. [PMID: 30682244 DOI: 10.1021/acssynbio.8b00266] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The development of programmable regulators that precisely and predictably control gene expression is a major goal of synthetic biology. Consequently, rapid high-throughput biochemical methods capable of quantitatively analyzing all components of gene expression would be of value in the characterization and optimization of regulator performance. In this study we demonstrate a novel application of RNA arrays, involving the production of reporter-protein arrays, to gene expression analysis. This method enables simultaneous quantification of both the transcription and post-transcription/translation components of gene expression, and it also allows the assessment of the orthogonality of multiple regulators. We use our method to directly compare the performance of a series of previously characterized synthetic post-transcriptional riboregulators, thus demonstrating its utility in the development of synthetic regulatory modules and evaluation of gene expression regulation in general.
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Affiliation(s)
- Masoud Norouzi
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
| | - Andrew R. Pickford
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
| | - Louise E. Butt
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
| | - Helen A. Vincent
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
| | - Anastasia J. Callaghan
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
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18
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Soto-Aceves MP, Cocotl-Yañez M, Merino E, Castillo-Juárez I, Cortés-López H, González-Pedrajo B, Díaz-Guerrero M, Servín-González L, Soberón-Chávez G. Inactivation of the quorum-sensing transcriptional regulators LasR or RhlR does not suppress the expression of virulence factors and the virulence of Pseudomonas aeruginosa PAO1. MICROBIOLOGY-SGM 2019; 165:425-432. [PMID: 30707095 DOI: 10.1099/mic.0.000778] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pseudomonas aeruginosa is an environmental bacterium but is also an opportunistic pathogen. The aim of this work is to evaluate the contribution of P. aeruginosa LasR and RhlR transcriptional regulators of the quorum-sensing response (QSR) to the production of virulence factors, and to its virulence in a mouse abscess model. The QSR is a complex regulatory network that modulates the expression of several virulence factors, including elastase, pyocyanin and rhamnolipids. LasR, when complexed with the auto-inducer 3-oxo-dodecanoyl lactone (3O-C12-HSL), produced by LasI, is at the top of the QSR regulatory cascade since it activates transcription of some genes encoding virulence factors (such as the gene coding for elastase, lasB) and also transcription of both rhlR and rhlI, encoding the synthase of the auto-inducer butanoyl-homoserine lactone (C4-HSL). In turn RhlR, coupled with C4-HSL, activates the transcription of genes encoding for the enzymes involved in pyocyanin and rhamnolipid production. Several efforts have been made to obtain inhibitors of LasR activity that would suppress the QSR. However, these attempts have used chemical compounds that might not be specific for LasR inactivation. In this work we show that individual inactivation of either lasR or rhlR did not block the QSR, nor did it impair P. aeruginosa virulence, and that even a lasR rhlR double mutant still presented residual virulence, even lacking the production of virulence factors. These results show that the inhibition of either lasR or rhlR is not a straightforward approach to blocking P. aeruginosa virulence, due to the great complexity of the QSR.
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Affiliation(s)
- Martín P Soto-Aceves
- 1Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Apdo, Postal 70228, Ciudad Universitaria, 04510, CDMX, México
| | - Miguel Cocotl-Yañez
- 2Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, CDMX, México
| | - Enrique Merino
- 3Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Mor, México
| | | | | | - Bertha González-Pedrajo
- 5Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, CDMX, México
| | - Miguel Díaz-Guerrero
- 5Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, CDMX, México
| | - Luis Servín-González
- 1Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Apdo, Postal 70228, Ciudad Universitaria, 04510, CDMX, México
| | - Gloria Soberón-Chávez
- 1Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México Apdo, Postal 70228, Ciudad Universitaria, 04510, CDMX, México
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Abstract
In bacteria and archaea, small RNAs (sRNAs) regulate complex networks through antisense interactions with target mRNAs in trans, and riboswitches regulate gene expression in cis based on the ability to bind small-molecule ligands. Although our understanding and characterization of these two important regulatory RNA classes is far from complete, these RNA-based mechanisms have proven useful for a wide variety of synthetic biology applications. Besides classic and contemporary applications in the realm of metabolic engineering and orthogonal gene control, this review also covers newer applications of regulatory RNAs as biosensors, logic gates, and tools to determine RNA-RNA interactions. A separate section focuses on critical insights gained and challenges posed by fundamental studies of sRNAs and riboswitches that should aid future development of synthetic regulatory RNAs.
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20
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Riboregulator elements as tools to engineer gene expression in cyanobacteria. Appl Microbiol Biotechnol 2018; 102:7717-7723. [DOI: 10.1007/s00253-018-9221-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 01/01/2023]
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21
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Stevens JT, Carothers JM. Programming Gene Expression by Engineering Transcript Stability Control and Processing in Bacteria. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jason T. Stevens
- University of Washington; Center for Synthetic Biology, Molecular Engineering and Sciences Institute, Departments of Chemical Engineering and Bioengineering; 4000 15th Ave NE, Seattle WA 98195-1654 USA
| | - James M. Carothers
- University of Washington; Center for Synthetic Biology, Molecular Engineering and Sciences Institute, Departments of Chemical Engineering and Bioengineering; 4000 15th Ave NE, Seattle WA 98195-1654 USA
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22
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Lee YJ, Kim SJ, Moon TS. Multilevel Regulation of Bacterial Gene Expression with the Combined STAR and Antisense RNA System. ACS Synth Biol 2018; 7:853-865. [PMID: 29429328 DOI: 10.1021/acssynbio.7b00322] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Synthetic small RNA regulators have emerged as a versatile tool to predictably control bacterial gene expression. Owing to their simple design principles, small size, and highly orthogonal behavior, these engineered genetic parts have been incorporated into genetic circuits. However, efforts to achieve more sophisticated cellular functions using RNA regulators have been hindered by our limited ability to integrate different RNA regulators into complex circuits. Here, we present a combined RNA regulatory system in Escherichia coli that uses small transcription activating RNA (STAR) and antisense RNA (asRNA) to activate or deactivate target gene expression in a programmable manner. Specifically, we demonstrated that the activated target output by the STAR system can be deactivated by expressing two different types of asRNAs: one binds to and sequesters the STAR regulator, affecting the transcription process, while the other binds to the target mRNA, affecting the translation process. We improved deactivation efficiencies (up to 96%) by optimizing each type of asRNA and then integrating the two optimized asRNAs into a single circuit. Furthermore, we demonstrated that the combined STAR and asRNA system can control gene expression in a reversible way and can regulate expression of a gene in the genome. Lastly, we constructed and simultaneously tested two A AND NOT B logic gates in the same cell to show sophisticated multigene regulation by the combined system. Our approach establishes a methodology for integrating multiple RNA regulators to rationally control multiple genes.
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Affiliation(s)
- Young Je Lee
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Soo-Jung Kim
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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23
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Sakamoto I, Abe K, Kawai S, Tsukakoshi K, Sakai Y, Sode K, Ikebukuro K. Improving the induction fold of riboregulators for cyanobacteria. RNA Biol 2018; 15:353-358. [PMID: 29303421 DOI: 10.1080/15476286.2017.1422470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Cyanobacteria are ideal cellular factories for biochemical production because of their ability to fix CO2 by photosynthesis and convert this molecule into biochemicals. Previously, we engineered a riboregulator that enables post-transcriptional gene regulation in the cyanobacterium Synechocystis sp. PCC 6803. Here, we improved the riboregulator by designing two RNA species, taRNA and crRNA, to enhance its induction fold. We inserted nucleotides into the crRNA loop to enhance intermolecular hybridization and successfully improved its induction fold. The engineered riboregulator exhibited a higher induction fold than the previously engineered riboregulator in both Escherichia coli and Synechocystis sp. PCC 6803. This improved riboregulator can be used to control gene expression over a wide dynamic range in cyanobacteria.
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Affiliation(s)
- Ippei Sakamoto
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Koichi Abe
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Sumiya Kawai
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Kaori Tsukakoshi
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Yuta Sakai
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Koji Sode
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
| | - Kazunori Ikebukuro
- a Department of Biotechnology and Life Science , Tokyo University of Agriculture and Technology , Koganei , Tokyo , Japan
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24
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Lee YJ, Moon TS. Design rules of synthetic non-coding RNAs in bacteria. Methods 2018; 143:58-69. [PMID: 29309838 DOI: 10.1016/j.ymeth.2018.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/31/2017] [Accepted: 01/03/2018] [Indexed: 12/21/2022] Open
Abstract
One of the long-term goals of synthetic biology is to develop designable genetic parts with predictable behaviors that can be utilized to implement diverse cellular functions. The discovery of non-coding RNAs and their importance in cellular processing have rapidly attracted researchers' attention towards designing functional non-coding RNA molecules. These synthetic non-coding RNAs have simple design principles governed by Watson-Crick base pairing, but exhibit increasingly complex functions. Importantly, due to their specific and modular behaviors, synthetic non-coding RNAs have been widely adopted to modulate transcription and translation of target genes. In this review, we summarize various design rules and strategies employed to engineer synthetic non-coding RNAs. Specifically, we discuss how RNA molecules can be transformed into powerful regulators and utilized to control target gene expression. With the establishment of generalizable non-coding RNA design rules, the research community will shift its focus to RNA regulators from protein regulators.
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Affiliation(s)
- Young Je Lee
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
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25
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Kim SK, Seong W, Han GH, Lee DH, Lee SG. CRISPR interference-guided multiplex repression of endogenous competing pathway genes for redirecting metabolic flux in Escherichia coli. Microb Cell Fact 2017; 16:188. [PMID: 29100516 PMCID: PMC5670510 DOI: 10.1186/s12934-017-0802-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/30/2017] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Multiplex control of metabolic pathway genes is essential for maximizing product titers and conversion yields of fuels, chemicals, and pharmaceuticals in metabolic engineering. To achieve this goal, artificial transcriptional regulators, such as clustered regularly interspaced short palindromic repeats (CRISPR) interference (CRISPRi), have been developed to specifically repress genes of interest. RESULTS In this study, we deployed a tunable CRISPRi system for multiplex repression of competing pathway genes and, thus, directed carbon flux toward production of molecules of interest in Escherichia coli. The tunable CRISPRi system with an array of sgRNAs successfully repressed four endogenous genes (pta, frdA, ldhA, and adhE) individually and in double, triple, or quadruple combination that are involved in the formation of byproducts (acetate, succinate, lactate, and ethanol) and the consumption of NADH in E. coli. Single-target CRISPRi effectively reduced the amount of each byproduct and, interestingly, pta repression also decreased ethanol production (41%), whereas ldhA repression increased ethanol production (197%). CRISPRi-mediated multiplex repression of competing pathway genes also resulted in simultaneous reductions of acetate, succinate, lactate, and ethanol production in E. coli. Among 15 conditions repressing byproduct-formation genes, we chose the quadruple-target CRISPRi condition to produce n-butanol in E. coli as a case study. When heterologous n-butanol-pathway enzymes were introduced into E. coli simultaneously repressing the expression of the pta, frdA, ldhA, and adhE genes via CRISPRi, n-butanol yield and productivity increased up to 5.4- and 3.2-fold, respectively. CONCLUSIONS We demonstrated the tunable CRISPRi system to be a robust platform for multiplex modulation of endogenous gene expression that can be used to enhance biosynthetic pathway productivity, with n-butanol as the test case. CRISPRi applications potentially enable the development of microbial "smart cell" factories capable of producing other industrially valuable products.
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Affiliation(s)
- Seong Keun Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141 Republic of Korea
| | - Wonjae Seong
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141 Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
| | - Gui Hwan Han
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141 Republic of Korea
| | - Dae-Hee Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141 Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
| | - Seung-Goo Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141 Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
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26
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Ghodasara A, Voigt CA. Balancing gene expression without library construction via a reusable sRNA pool. Nucleic Acids Res 2017; 45:8116-8127. [PMID: 28609783 PMCID: PMC5737548 DOI: 10.1093/nar/gkx530] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/07/2017] [Indexed: 01/06/2023] Open
Abstract
Balancing protein expression is critical when optimizing genetic systems. Typically, this requires library construction to vary the genetic parts controlling each gene, which can be expensive and time-consuming. Here, we develop sRNAs corresponding to 15nt ‘target’ sequences that can be inserted upstream of a gene. The targeted gene can be repressed from 1.6- to 87-fold by controlling sRNA expression using promoters of different strength. A pool is built where six sRNAs are placed under the control of 16 promoters that span a ∼103-fold range of strengths, yielding ∼107 combinations. This pool can simultaneously optimize up to six genes in a system. This requires building only a single system-specific construct by placing a target sequence upstream of each gene and transforming it with the pre-built sRNA pool. The resulting library is screened and the top clone is sequenced to determine the promoter controlling each sRNA, from which the fold-repression of the genes can be inferred. The system is then rebuilt by rationally selecting parts that implement the optimal expression of each gene. We demonstrate the versatility of this approach by using the same pool to optimize a metabolic pathway (β-carotene) and genetic circuit (XNOR logic gate).
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Affiliation(s)
- Amar Ghodasara
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Christopher A Voigt
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
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27
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Lahiry A, Stimple SD, Wood DW, Lease RA. Retargeting a Dual-Acting sRNA for Multiple mRNA Transcript Regulation. ACS Synth Biol 2017; 6:648-658. [PMID: 28067500 DOI: 10.1021/acssynbio.6b00261] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Multitargeting small regulatory RNAs (sRNAs) represent a potentially useful tool for metabolic engineering applications. Natural multitargeting sRNAs govern bacterial gene expression by binding to the translation initiation regions of protein-coding mRNAs through base pairing. We designed an Escherichia coli based genetic system to create and assay dual-acting retargeted-sRNA variants. The variants can be assayed for coordinate translational regulation of two alternate mRNA leaders fused to independent reporter genes. Accordingly, we began with the well-characterized E. coli native DsrA sRNA. The merits of using DsrA include its well-characterized separation of function into two independently folded stem-loop domains, wherein alterations at one stem do not necessarily abolish activity at the other stem. Expression of the sRNA and each reporter mRNA was independently controlled by small inducer molecules, allowing precise quantification of the regulatory effects of each sRNA:mRNA interaction in vivo with a microtiter plate assay. Using this system, we semirationally designed DsrA variants screened in E. coli for their ability to regulate key mRNA leader sequences from the Clostridium acetobutylicum n-butanol synthesis pathway. To coordinate intervention at two points in a metabolic pathway, we created bifunctional sRNA prototypes by combining sequences from two singly retargeted DsrA variants. This approach constitutes a platform for designing sRNAs to specifically target arbitrary mRNA transcript sequences, and thus provides a generalizable tool for retargeting and characterizing multitarget sRNAs for metabolic engineering.
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Affiliation(s)
- Ashwin Lahiry
- Department
of Microbiology, The Ohio State University, 484 W. 12th Avenue, Columbus, Ohio 43210, United States
| | - Samuel D. Stimple
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
| | - David W. Wood
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
- Department
of Microbiology, The Ohio State University, 484 W. 12th Avenue, Columbus, Ohio 43210, United States
| | - Richard A. Lease
- Department
of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States
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28
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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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29
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Hoynes-O’Connor A, Moon TS. Development of Design Rules for Reliable Antisense RNA Behavior in E. coli. ACS Synth Biol 2016; 5:1441-1454. [PMID: 27434774 DOI: 10.1021/acssynbio.6b00036] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A key driver of synthetic biology is the development of designable genetic parts with predictable behaviors that can be quickly implemented in complex genetic systems. However, the intrinsic complexity of gene regulation can make the rational design of genetic parts challenging. This challenge is apparent in the design of antisense RNA (asRNA) regulators. Though asRNAs are well-known regulators, the literature governing their design is conflicting and leaves the synthetic biology community without clear asRNA design rules. The goal of this study is to perform a comprehensive experimental characterization and statistical analysis of 121 unique asRNA regulators in order to resolve the conflicts that currently exist in the literature. asRNAs usually consist of two regions, the Hfq binding site and the target binding region (TBR). First, the behaviors of several high-performing Hfq binding sites were compared, in terms of their ability to improve repression efficiencies and their orthogonality. Next, a large-scale analysis of TBR design parameters identified asRNA length, the thermodynamics of asRNA-mRNA complex formation, and the percent of target mismatch as key parameters for TBR design. These parameters were used to develop simple asRNA design rules. Finally, these design rules were applied to construct both a simple and a complex genetic circuit containing different asRNAs, and predictable behavior was observed in both circuits. The results presented in this study will drive synthetic biology forward by providing useful design guidelines for the construction of asRNA regulators with predictable behaviors.
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Affiliation(s)
- Allison Hoynes-O’Connor
- Department
of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department
of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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30
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Zhao Y, Fan J, Li J, Li J, Zhou X, Li C. Visualized and precise design of artificial small RNAs for regulating T7 RNA polymerase and enhancing recombinant protein folding in Escherichia coli. Synth Syst Biotechnol 2016; 1:265-270. [PMID: 29062952 PMCID: PMC5625733 DOI: 10.1016/j.synbio.2016.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 11/18/2022] Open
Abstract
Small non-coding RNAs (sRNAs) have received much attention in recent years due to their unique biological properties, which can efficiently and specifically tune target gene expressions in bacteria. Inspired by natural sRNAs, recent works have proposed the use of artificial sRNAs (asRNAs) as genetic tools to regulate desired gene that has been applied in several fields, such as metabolic engineering and bacterial physiology studies. However, the rational design of asRNAs is still a challenge. In this study, we proposed structure and length as two criteria to implement rational visualized and precise design of asRNAs. T7 expression system was one of the most useful recombinant protein expression systems. However, it was deeply limited by the formation of inclusion body. To settle this problem, we designed a series of asRNAs to inhibit the T7 RNA polymerase (Gene1) expression to balance the rate between transcription and folding of recombinant protein. Based on the heterologous expression of Aspergillus oryzae Li-3 glucuronidase in E. coli, the asRNA-antigene1-17bp can effectively decrease the inclusion body and increase the enzyme activity by 169.9%.
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31
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Gu P, Su T, Wang Q, Liang Q, Qi Q. Tunable switch mediated shikimate biosynthesis in an engineered non-auxotrophic Escherichia coli. Sci Rep 2016; 6:29745. [PMID: 27406890 PMCID: PMC4942831 DOI: 10.1038/srep29745] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/23/2016] [Indexed: 12/28/2022] Open
Abstract
Shikimate is a key intermediate in the synthesis of neuraminidase inhibitors. Compared with traditional methods, microbial production of shikimate has the advantages of environmental friendliness, low cost, feed stock renewability, and product selectivity and diversity. Despite these advantages, shikimate kinase I and II respectively encoded by aroK and aroL are inactivated in most shikimate microbial producers, thus requiring the addition of aromatic compounds during the fermentation process. To overcome this problem, we constructed a non-auxotrophic, shikimate-synthesising strain of Escherichia coli. By inactivation of repressor proteins, blocking of competitive pathways and overexpression of key enzymes, we increased the shikimate production of wild-type E. coli BW25113 to 1.73 g/L. We then designed a tunable switch that can conditionally decrease gene expression and substituted it for the original aroK promoters. Expression of aroK in the resulting P-9 strain was maintained at a high level during the growth phase and then reduced at a suitable time by addition of an optimal concentration of inducer. In 5-L fed-batch fermentation, strain P-9 produced 13.15 g/L shikimate without the addition of any aromatic compounds. The tunable switch developed in this study is an efficient tool for regulating indispensable genes involved in critical metabolic pathways.
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Affiliation(s)
- Pengfei Gu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
| | - Tianyuan Su
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
| | - Qian Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
| | - Quanfeng Liang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
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32
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Lee YJ, Hoynes-O'Connor A, Leong MC, Moon TS. Programmable control of bacterial gene expression with the combined CRISPR and antisense RNA system. Nucleic Acids Res 2016; 44:2462-73. [PMID: 26837577 PMCID: PMC4797300 DOI: 10.1093/nar/gkw056] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 12/16/2022] Open
Abstract
A central goal of synthetic biology is to implement diverse cellular functions by predictably controlling gene expression. Though research has focused more on protein regulators than RNA regulators, recent advances in our understanding of RNA folding and functions have motivated the use of RNA regulators. RNA regulators provide an advantage because they are easier to design and engineer than protein regulators, potentially have a lower burden on the cell and are highly orthogonal. Here, we combine the CRISPR system from Streptococcus pyogenes and synthetic antisense RNAs (asRNAs) in Escherichia coli strains to repress or derepress a target gene in a programmable manner. Specifically, we demonstrate for the first time that the gene target repressed by the CRISPR system can be derepressed by expressing an asRNA that sequesters a small guide RNA (sgRNA). Furthermore, we demonstrate that tunable levels of derepression can be achieved (up to 95%) by designing asRNAs that target different regions of a sgRNA and by altering the hybridization free energy of the sgRNA-asRNA complex. This new system, which we call the combined CRISPR and asRNA system, can be used to reversibly repress or derepress multiple target genes simultaneously, allowing for rational reprogramming of cellular functions.
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Affiliation(s)
- Young Je Lee
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Allison Hoynes-O'Connor
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Matthew C Leong
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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33
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Tools and Principles for Microbial Gene Circuit Engineering. J Mol Biol 2016; 428:862-88. [DOI: 10.1016/j.jmb.2015.10.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/26/2022]
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34
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Becker J, Gießelmann G, Hoffmann SL, Wittmann C. Corynebacterium glutamicum for Sustainable Bioproduction: From Metabolic Physiology to Systems Metabolic Engineering. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 162:217-263. [DOI: 10.1007/10_2016_21] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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35
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36
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Meyer S, Chappell J, Sankar S, Chew R, Lucks JB. Improving fold activation of small transcription activating RNAs (STARs) with rational RNA engineering strategies. Biotechnol Bioeng 2015; 113:216-25. [PMID: 26134708 DOI: 10.1002/bit.25693] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/04/2015] [Accepted: 06/23/2015] [Indexed: 01/16/2023]
Abstract
Regulatory RNAs have become integral components of the synthetic biology and bioengineering toolbox for controlling gene expression. We recently expanded this toolbox by creating small transcription activating RNAs (STARs) that act by disrupting the formation of a target transcriptional terminator hairpin placed upstream of a gene. While STARs are a promising addition to the repertoire of RNA regulators, much work remains to be done to optimize the fold activation of these systems. Here we apply rational RNA engineering strategies to improve the fold activation of two STAR regulators. We demonstrate that a combination of promoter strength tuning and multiple RNA engineering strategies can improve fold activation from 5.4-fold to 13.4-fold for a STAR regulator derived from the pbuE riboswitch terminator. We then validate the generality of our approach and show that these same strategies improve fold activation from 2.1-fold to 14.6-fold for an unrelated STAR regulator, opening the door to creating a range of additional STARs to use in a broad array of biotechnologies. We also establish that the optimizations preserve the orthogonality of these STARs between themselves and a set of RNA transcriptional repressors, enabling these optimized STARs to be used in sophisticated circuits.
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Affiliation(s)
- Sarai Meyer
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853
| | - James Chappell
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853
| | - Sitara Sankar
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853
| | - Rebecca Chew
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853
| | - Julius B Lucks
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853.
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37
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Zess EK, Begemann MB, Pfleger BF. Construction of new synthetic biology tools for the control of gene expression in the cyanobacterium Synechococcus sp. strain PCC 7002. Biotechnol Bioeng 2015; 113:424-32. [PMID: 26192329 DOI: 10.1002/bit.25713] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 06/24/2015] [Accepted: 07/14/2015] [Indexed: 12/18/2022]
Abstract
Predictive control of gene expression is an essential tool for developing synthetic biological systems. The current toolbox for controlling gene expression in cyanobacteria is a barrier to more in-depth genetic analysis and manipulation. Towards relieving this bottleneck, this work describes the use of synthetic biology to construct an anhydrotetracycline-based induction system and adapt a trans-acting small RNA (sRNA) system for use in the cyanobacterium Synechococcus sp. strain PCC 7002. An anhydrotetracycline-inducible promoter was developed to maximize intrinsic strength and dynamic range. The resulting construct, PEZtet , exhibited tight repression and a maximum 32-fold induction upon addition of anhydrotetracycline. Additionally, a sRNA system based on the Escherichia coli IS10 RNA-IN/OUT regulator was adapted for use in Synechococcus sp. strain PCC 7002. This system exhibited 70% attenuation of target gene expression, providing a demonstration of the use of sRNAs for differential gene expression in cyanobacteria. These systems were combined to produce an inducible sRNA system, which demonstrated 59% attenuation of target gene expression. Lastly, the role of Hfq, a critical component of sRNA systems in E. coli, was investigated. Genetic studies showed that the Hfq homolog in Synechococcus sp. strain PCC 7002 did not impact repression by the engineered sRNA system. In summary, this work describes new synthetic biology tools that can be applied to physiological studies, metabolic engineering, or sRNA platforms in Synechococcus sp. strain PCC 7002.
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Affiliation(s)
- Erin K Zess
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin, 53706
| | - Matthew B Begemann
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin, 53706.,Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1550 Linden Dr., Madison, Wisconsin, 53706
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, Wisconsin, 53706. .,Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1550 Linden Dr., Madison, Wisconsin, 53706.
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38
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Massaiu I, Pasotti L, Casanova M, Politi N, Zucca S, Cusella De Angelis MG, Magni P. Quantification of the gene silencing performances of rationally-designed synthetic small RNAs. SYSTEMS AND SYNTHETIC BIOLOGY 2015; 9:107-23. [PMID: 26279705 DOI: 10.1007/s11693-015-9177-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 06/12/2015] [Accepted: 07/27/2015] [Indexed: 11/30/2022]
Abstract
Small RNAs (sRNAs) are genetic tools for the efficient and specific tuning of target genes expression in bacteria. Inspired by naturally occurring sRNAs, recent works proposed the use of artificial sRNAs in synthetic biology for predictable repression of the desired genes. Their potential was demonstrated in several application fields, such as metabolic engineering and bacterial physiology studies. Guidelines for the rational design of novel sRNAs have been recently proposed. According to these guidelines, in this work synthetic sRNAs were designed, constructed and quantitatively characterized in Escherichia coli. An sRNA targeting the reporter gene RFP was tested by measuring the specific gene silencing when RFP was expressed at different transcription levels, under the control of different promoters, in different strains, and in single-gene or operon architecture. The sRNA level was tuned by using plasmids maintained at different copy numbers. Results demonstrated that RFP silencing worked as expected in an sRNA and mRNA expression-dependent fashion. A mathematical model was used to support sRNA characterization and to estimate an efficiency-related parameter that can be used to compare the performance of the designed sRNA. Gene silencing was also successful when RFP was placed in a two-gene synthetic operon, while the non-target gene (GFP) in the operon was not considerably affected. Finally, silencing was evaluated for another designed sRNA targeting the endogenous lactate dehydrogenase gene. The quantitative study performed in this work elucidated interesting performance-related and context-dependent features of synthetic sRNAs that will strongly support predictable gene silencing in disparate basic or applied research studies.
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Affiliation(s)
- Ilaria Massaiu
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - Lorenzo Pasotti
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - Michela Casanova
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - Nicolò Politi
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - Susanna Zucca
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | | | - Paolo Magni
- Laboratory of Bioinformatics, Mathematical Modelling and Synthetic Biology, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy ; Centre for Health Technologies, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
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39
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Paired-termini antisense RNA mediated inhibition of DoxR in Streptomyces peucetius ATCC 27952. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0810-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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40
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Chappell J, Watters KE, Takahashi MK, Lucks JB. A renaissance in RNA synthetic biology: new mechanisms, applications and tools for the future. Curr Opin Chem Biol 2015; 28:47-56. [PMID: 26093826 DOI: 10.1016/j.cbpa.2015.05.018] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/15/2015] [Accepted: 05/19/2015] [Indexed: 01/01/2023]
Abstract
Since our ability to engineer biological systems is directly related to our ability to control gene expression, a central focus of synthetic biology has been to develop programmable genetic regulatory systems. Researchers are increasingly turning to RNA regulators for this task because of their versatility, and the emergence of new powerful RNA design principles. Here we review advances that are transforming the way we use RNAs to engineer biological systems. First, we examine new designable RNA mechanisms that are enabling large libraries of regulators with protein-like dynamic ranges. Next, we review emerging applications, from RNA genetic circuits to molecular diagnostics. Finally, we describe new experimental and computational tools that promise to accelerate our understanding of RNA folding, function and design.
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Affiliation(s)
- James Chappell
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Kyle E Watters
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Melissa K Takahashi
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Julius B Lucks
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States.
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41
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Chaudhary AK, Na D, Lee EY. Rapid and high-throughput construction of microbial cell-factories with regulatory noncoding RNAs. Biotechnol Adv 2015; 33:914-30. [PMID: 26027891 DOI: 10.1016/j.biotechadv.2015.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/27/2015] [Accepted: 05/27/2015] [Indexed: 12/11/2022]
Abstract
Due to global crises such as pollution and depletion of fossil fuels, sustainable technologies based on microbial cell-factories have been garnering great interest as an alternative to chemical factories. The development of microbial cell-factories is imperative in cutting down the overall manufacturing cost. Thus, diverse metabolic engineering strategies and engineering tools have been established to obtain a preferred genotype and phenotype displaying superior productivity. However, these tools are limited to only a handful of genes with permanent modification of a genome and significant labor costs, and this is one of the bottlenecks associated with biofactory construction. Therefore, a groundbreaking rapid and high-throughput engineering tool is needed for efficient construction of microbial cell-factories. During the last decade, copious small noncoding RNAs (ncRNAs) have been discovered in bacteria. These are involved in substantial regulatory roles like transcriptional and post-transcriptional gene regulation by modulating mRNA elongation, stability, or translational efficiency. Because of their vulnerability, ncRNAs can be used as another layer of conditional control over gene expression without modifying chromosomal sequences, and hence would be a promising high-throughput tool for metabolic engineering. Here, we review successful design principles and applications of ncRNAs for high-throughput metabolic engineering or physiological studies of diverse industrially important microorganisms.
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Affiliation(s)
- Amit Kumar Chaudhary
- Department of Chemical Engineering, Kyung Hee University, Gyeonggi-do 446-701, Republic of Korea
| | - Dokyun Na
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Republic of Korea.
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Gyeonggi-do 446-701, Republic of Korea.
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42
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Sakai Y, Abe K, Nakashima S, Ellinger JJ, Ferri S, Sode K, Ikebukuro K. Scaffold-fused riboregulators for enhanced gene activation in Synechocystis sp. PCC 6803. Microbiologyopen 2015; 4:533-40. [PMID: 25865486 PMCID: PMC4554450 DOI: 10.1002/mbo3.257] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 02/27/2015] [Accepted: 03/09/2015] [Indexed: 12/29/2022] Open
Abstract
Cyanobacteria are an attractive host for biofuel production because they can produce valuable chemical compounds from CO2 fixed by photosynthesis. However, the available genetic tools that enable precise gene regulation for the applications of synthetic biology are insufficient. Previously, we engineered an RNA-based posttranscriptional regulator, termed riboregulator, for the control of target gene expression in cyanobacterium Synechocystis sp. PCC 6803. Moreover, we enhanced the gene regulation ability of the riboregulators in Escherichia coli by fusing and engineering a scaffold sequence derived from naturally occurring E. coli noncoding small RNAs. Here, we demonstrated that the scaffold sequence fused to the riboregulators improved their gene regulation ability in Synechocystis sp. PCC 6803. To further improve gene regulation, we expressed an exogenous RNA chaperone protein that is responsible for noncoding small RNA-mediated gene regulation, which resulted in higher target gene expression. The scaffold sequence derived from natural E. coli noncoding small RNAs is effective for designing RNA-based genetic tools and scaffold-fused riboregulators are a strong RNA-tool to regulate gene expression in cyanobacteria.
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Affiliation(s)
- Yuta Sakai
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Koichi Abe
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Saki Nakashima
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - James J Ellinger
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Stefano Ferri
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Koji Sode
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Kazunori Ikebukuro
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.,CREST, Japan Science and Technology Agency, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
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43
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Tsai CH, Liao R, Chou B, Contreras LM. Transcriptional analysis of Deinococcus radiodurans reveals novel small RNAs that are differentially expressed under ionizing radiation. Appl Environ Microbiol 2015; 81:1754-64. [PMID: 25548054 PMCID: PMC4325154 DOI: 10.1128/aem.03709-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/19/2014] [Indexed: 02/08/2023] Open
Abstract
Small noncoding RNAs (sRNAs) are posttranscriptional regulators that have been identified in multiple species and shown to play essential roles in responsive mechanisms to environmental stresses. The natural ability of specific bacteria to resist high levels of radiation has been of high interest to mechanistic studies of DNA repair and biomolecular protection. Deinococcus radiodurans is a model extremophile for radiation studies that can survive doses of ionizing radiation of >12,000 Gy, 3,000 times higher than for most vertebrates. Few studies have investigated posttranscriptional regulatory mechanisms of this organism that could be relevant in its general gene regulatory patterns. In this study, we identified 199 potential sRNA candidates in D. radiodurans by whole-transcriptome deep sequencing analysis and confirmed the expression of 41 sRNAs by Northern blotting and reverse transcriptase PCR (RT-PCR). A total of 8 confirmed sRNAs showed differential expression during recovery after acute ionizing radiation (15 kGy). We have also found and confirmed 7 sRNAs in Deinococcus geothermalis, a closely related radioresistant species. The identification of several novel sRNAs in Deinococcus bacteria raises important questions about the evolution and nature of global gene regulation in radioresistance.
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Affiliation(s)
- Chen-Hsun Tsai
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Rick Liao
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Brendan Chou
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
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44
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Creating small transcription activating RNAs. Nat Chem Biol 2015; 11:214-20. [PMID: 25643173 DOI: 10.1038/nchembio.1737] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 11/25/2014] [Indexed: 12/28/2022]
Abstract
We expanded the mechanistic capability of small RNAs by creating an entirely synthetic mode of regulation: small transcription activating RNAs (STARs). Using two strategies, we engineered synthetic STAR regulators to disrupt the formation of an intrinsic transcription terminator placed upstream of a gene in Escherichia coli. This resulted in a group of four highly orthogonal STARs that had up to 94-fold activation. By systematically modifying sequence features of this group, we derived design principles for STAR function, which we then used to forward engineer a STAR that targets a terminator found in the Escherichia coli genome. Finally, we showed that STARs could be combined in tandem to create previously unattainable RNA-only transcriptional logic gates. STARs provide a new mechanism of regulation that will expand our ability to use small RNAs to construct synthetic gene networks that precisely control gene expression.
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45
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Bak G, Choi JS, Kim W, Suk S, Lee Y. An Effective Method for Specific Gene Silencing in Escherichia coli Using Artificial Small RNA. Methods Mol Biol 2015; 1316:211-225. [PMID: 25967064 DOI: 10.1007/978-1-4939-2730-2_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Knockdown or silencing of a specific gene presents a powerful strategy for elucidating gene function in a variety of organisms. To date, efficient silencing methods have been established in eukaryotes, but not bacteria. In this chapter, an efficient and versatile gene silencing method using artificial small RNA (afsRNA) is described. For this purpose, target-recognizing sequences were introduced in specially designed RNA scaffolds to exist as single-stranded stretches in afsRNA. The translation initiation region of target genes was used as the sequence for afsRNA recognition, based on the theory that this site is usually highly accessible to ribosomes, and therefore, possibly, afsRNA. Two genes transcribed as monocistrons were tested with our protocol. Both genes were effectively silenced by their cognate afsRNAs.
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Affiliation(s)
- Geunu Bak
- Department of Chemistry, KAIST, Daejeon, 305-701, Korea
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46
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Nielsen AAK, Voigt CA. Multi-input CRISPR/Cas genetic circuits that interface host regulatory networks. Mol Syst Biol 2014; 10:763. [PMID: 25422271 PMCID: PMC4299604 DOI: 10.15252/msb.20145735] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/26/2014] [Accepted: 10/29/2014] [Indexed: 12/24/2022] Open
Abstract
Genetic circuits require many regulatory parts in order to implement signal processing or execute algorithms in cells. A potentially scalable approach is to use dCas9, which employs small guide RNAs (sgRNAs) to repress genetic loci via the programmability of RNA:DNA base pairing. To this end, we use dCas9 and designed sgRNAs to build transcriptional logic gates and connect them to perform computation in living cells. We constructed a set of NOT gates by designing five synthetic Escherichia coli σ70 promoters that are repressed by corresponding sgRNAs, and these interactions do not exhibit crosstalk between each other. These sgRNAs exhibit high on-target repression (56- to 440-fold) and negligible off-target interactions (< 1.3-fold). These gates were connected to build larger circuits, including the Boolean-complete NOR gate and a 3-gate circuit consisting of four layered sgRNAs. The synthetic circuits were connected to the native E. coli regulatory network by designing output sgRNAs to target an E. coli transcription factor (malT). This converts the output of a synthetic circuit to a switch in cellular phenotype (sugar utilization, chemotaxis, phage resistance).
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Affiliation(s)
- Alec A K Nielsen
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Christopher A Voigt
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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47
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Copeland MF, Politz MC, Pfleger BF. Application of TALEs, CRISPR/Cas and sRNAs as trans-acting regulators in prokaryotes. Curr Opin Biotechnol 2014; 29:46-54. [PMID: 24632195 PMCID: PMC4162867 DOI: 10.1016/j.copbio.2014.02.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/28/2014] [Accepted: 02/13/2014] [Indexed: 01/09/2023]
Abstract
The last several years have witnessed an explosion in the understanding and use of novel, versatile trans-acting elements. TALEs, CRISPR/Cas, and sRNAs can be easily fashioned to bind any specific sequence of DNA (TALEs, CRISPR/Cas) or RNA (sRNAs) because of the simple rules governing their interactions with nucleic acids. This unique property enables these tools to repress the expression of genes at the transcriptional or post-transcriptional levels, respectively, without prior manipulation of cis-acting and/or chromosomal target DNA sequences. These tools are now being harnessed by synthetic biologists, particularly those in the eukaryotic community, for genome-wide regulation, editing, or epigenetic studies. Here we discuss the exciting opportunities for using TALEs, CRISPR/Cas, and sRNAs as synthetic trans-acting regulators in prokaryotes.
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Affiliation(s)
- Matthew F Copeland
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Mark C Politz
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Brian F Pfleger
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA.
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Fine-Tuning of the Fatty Acid Pathway by Synthetic Antisense RNA for Enhanced (2S)-Naringenin Production from l-Tyrosine in Escherichia coli. Appl Environ Microbiol 2014; 80:7283-92. [PMID: 25239896 DOI: 10.1128/aem.02411-14] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/12/2014] [Indexed: 12/26/2022] Open
Abstract
Malonyl coenzyme A (malonyl-CoA) is an important precursor for the synthesis of natural products, such as polyketides and flavonoids. The majority of this cofactor often is consumed for producing fatty acids and phospholipids, leaving only a small amount of cellular malonyl-CoA available for producing the target compound. The tuning of malonyl-CoA into heterologous pathways yields significant phenotypic effects, such as growth retardation and even cell death. In this study, fine-tuning of the fatty acid pathway in Escherichia coli with antisense RNA (asRNA) to balance the demands on malonyl-CoA for target-product synthesis and cell health was proposed. To establish an efficient asRNA system, the relationship between sequence and function for asRNA was explored. It was demonstrated that the gene-silencing effect of asRNA could be tuned by directing asRNA to different positions in the 5'-UTR (untranslated region) of the target gene. Based on this principle, the activity of asRNA was quantitatively tailored to balance the need for malonyl-CoA in cell growth and the production of the main flavonoid precursor, (2S)-naringenin. Appropriate inhibitory efficiency of the anti-fabB/fabF asRNA improved the production titer by 431% (391 mg/liter). Therefore, the strategy presented in this study provided a useful tool for the fine-tuning of endogenous gene expression in bacteria.
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49
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A versatile framework for microbial engineering using synthetic non-coding RNAs. Nat Rev Microbiol 2014; 12:341-54. [DOI: 10.1038/nrmicro3244] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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50
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Sakai Y, Abe K, Nakashima S, Yoshida W, Ferri S, Sode K, Ikebukuro K. Improving the gene-regulation ability of small RNAs by scaffold engineering in Escherichia coli. ACS Synth Biol 2014; 3:152-62. [PMID: 24328142 DOI: 10.1021/sb4000959] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Noncoding small RNAs are involved in transcriptional and post-transcriptional gene regulation of target mRNAs by modulating mRNA elongation, stability, or translational efficiency. Many natural trans-encoded small RNAs contain a scaffold that allows binding of the RNA chaperone protein Hfq for conditional gene regulation. Here, we improved the gene regulation abilities of small RNAs by directly fusing the natural Escherichia coli trans-encoded small RNA-derived scaffolds, including Hfq-binding and rho-independent transcription terminator sequences, to the 3' end of the small RNAs that mediate RNA-based gene regulation. As target small RNAs to improve their gene regulation abilities, we selected small RNAs of artificial post-transcriptional riboregulators and transcriptional attenuators. Four different small RNA scaffolds were fused to the riboregulator and attenuator-derived small RNAs. Mutations were introduced into the best small RNA scaffold to improve its gene-regulation ability further. As a result, mutations predicted to stabilize the secondary structures of the small RNA scaffolds dramatically increased its ability to regulate gene expression of both the post-transcriptional riboregulator and transcriptional attenuator systems. We believe our engineered small RNA scaffolds are applicable to other RNA regulators for improving regulatory activity, and engineered small RNA scaffolds may present a valuable strategy to regulate target gene expression strongly.
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Affiliation(s)
- Yuta Sakai
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Koichi Abe
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Saki Nakashima
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Wataru Yoshida
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Stefano Ferri
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Koji Sode
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Kazunori Ikebukuro
- Department
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
- Japan Science and Technology Agency, CREST, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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