51
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Xiu Y, Jang S, Jones JA, Zill NA, Linhardt RJ, Yuan Q, Jung GY, Koffas MAG. Naringenin-responsive riboswitch-based fluorescent biosensor module for Escherichia coli co-cultures. Biotechnol Bioeng 2017; 114:2235-2244. [PMID: 28543037 DOI: 10.1002/bit.26340] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/11/2017] [Accepted: 05/16/2017] [Indexed: 12/29/2022]
Abstract
The ability to design and construct combinatorial synthetic metabolic pathways has far exceeded our capacity for efficient screening and selection of the resulting microbial strains. The need for high-throughput rapid screening techniques is of upmost importance for the future of synthetic biology and metabolic engineering. Here we describe the development of an RNA riboswitch-based biosensor module with dual fluorescent reporters, and demonstrate a high-throughput flow cytometry-based screening method for identification of naringenin over producing Escherichia coli strains in co-culture. Our efforts helped identify a number of key operating parameters that affect biosensor performance, including the selection of promoter and linker elements within the sensor-actuator domain, and the effect of host strain, fermentation time, and growth medium on sensor dynamic range. The resulting biosensor demonstrates a high correlation between specific fluorescence of the biosensor strain and naringenin titer produced by the second member of the synthetic co-culture system. This technique represents a novel application for synthetic microbial co-cultures and can be expanded from naringenin to any metabolite if a suitable riboswitch is identified. The co-culture technique presented here can be applied to a variety of target metabolites in combination with the SELEX approach for aptamer design. Due to the compartmentalization of the two genetic constructs responsible for production and detection into separate cells and application as independent modules of a synthetic microbial co-culture we have subsequently reduced the need for re-optimization of the producer module when the biosensor is replaced or removed. Biotechnol. Bioeng. 2017;114: 2235-2244. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yu Xiu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, China.,Beijing Key Laboratory of Bioactive Substances and Functional Food, Beijing Union University, Beijing, China.,Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Sungho Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, Korea
| | - J Andrew Jones
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York.,Department of Chemistry, Hamilton College, Clinton, New York
| | - Nicholas A Zill
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Robert J Linhardt
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, China
| | - Gyoo Yeol Jung
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, Korea.,School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, Korea
| | - Mattheos A G Koffas
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
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52
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Ausländer S, Ausländer D, Fussenegger M. Synthetische Biologie - die Synthese der Biologie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201609229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Simon Ausländer
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
| | - David Ausländer
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering; ETH Zürich; Mattenstrasse 26 4058 Basel Schweiz
- Faculty of Science; Universität Basel; Mattenstrasse 26 4058 Basel Schweiz
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53
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Ausländer S, Ausländer D, Fussenegger M. Synthetic Biology-The Synthesis of Biology. Angew Chem Int Ed Engl 2017; 56:6396-6419. [PMID: 27943572 DOI: 10.1002/anie.201609229] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/17/2016] [Indexed: 01/01/2023]
Abstract
Synthetic biology concerns the engineering of man-made living biomachines from standardized components that can perform predefined functions in a (self-)controlled manner. Different research strategies and interdisciplinary efforts are pursued to implement engineering principles to biology. The "top-down" strategy exploits nature's incredible diversity of existing, natural parts to construct synthetic compositions of genetic, metabolic, or signaling networks with predictable and controllable properties. This mainly application-driven approach results in living factories that produce drugs, biofuels, biomaterials, and fine chemicals, and results in living pills that are based on engineered cells with the capacity to autonomously detect and treat disease states in vivo. In contrast, the "bottom-up" strategy seeks to be independent of existing living systems by designing biological systems from scratch and synthesizing artificial biological entities not found in nature. This more knowledge-driven approach investigates the reconstruction of minimal biological systems that are capable of performing basic biological phenomena, such as self-organization, self-replication, and self-sustainability. Moreover, the syntheses of artificial biological units, such as synthetic nucleotides or amino acids, and their implementation into polymers inside living cells currently set the boundaries between natural and artificial biological systems. In particular, the in vitro design, synthesis, and transfer of complete genomes into host cells point to the future of synthetic biology: the creation of designer cells with tailored desirable properties for biomedicine and biotechnology.
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Affiliation(s)
- Simon Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - David Ausländer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland.,Faculty of Science, University of Basel, Mattenstrasse 26, 4058, Basel, Switzerland
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54
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Hallberg ZF, Su Y, Kitto RZ, Hammond MC. Engineering and In Vivo Applications of Riboswitches. Annu Rev Biochem 2017; 86:515-539. [PMID: 28375743 DOI: 10.1146/annurev-biochem-060815-014628] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Riboswitches are common gene regulatory units mostly found in bacteria that are capable of altering gene expression in response to a small molecule. These structured RNA elements consist of two modular subunits: an aptamer domain that binds with high specificity and affinity to a target ligand and an expression platform that transduces ligand binding to a gene expression output. Significant progress has been made in engineering novel aptamer domains for new small molecule inducers of gene expression. Modified expression platforms have also been optimized to function when fused with both natural and synthetic aptamer domains. As this field expands, the use of these privileged scaffolds has permitted the development of tools such as RNA-based fluorescent biosensors. In this review, we summarize the methods that have been developed to engineer new riboswitches and highlight applications of natural and synthetic riboswitches in enzyme and strain engineering, in controlling gene expression and cellular physiology, and in real-time imaging of cellular metabolites and signals.
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Affiliation(s)
- Zachary F Hallberg
- Department of Chemistry, University of California, Berkeley, California 94720;
| | - Yichi Su
- Department of Chemistry, University of California, Berkeley, California 94720;
| | - Rebekah Z Kitto
- Department of Chemistry, University of California, Berkeley, California 94720;
| | - Ming C Hammond
- Department of Chemistry, University of California, Berkeley, California 94720; .,Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
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55
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Genetic biosensors for small-molecule products: Design and applications in high-throughput screening. Front Chem Sci Eng 2017. [DOI: 10.1007/s11705-017-1629-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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56
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Etzel M, Mörl M. Synthetic Riboswitches: From Plug and Pray toward Plug and Play. Biochemistry 2017; 56:1181-1198. [PMID: 28206750 DOI: 10.1021/acs.biochem.6b01218] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In synthetic biology, metabolic engineering, and gene therapy, there is a strong demand for orthogonal or externally controlled regulation of gene expression. Here, RNA-based regulatory devices represent a promising emerging alternative to proteins, allowing a fast and direct control of gene expression, as no synthesis of regulatory proteins is required. Besides programmable ribozyme elements controlling mRNA stability, regulatory RNA structures in untranslated regions are highly interesting for engineering approaches. Riboswitches are especially well suited, as they show a modular composition of sensor and response elements, allowing a free combination of different modules in a plug-and-play-like mode. The sensor or aptamer domain specifically interacts with a trigger molecule as a ligand, modulating the activity of the adjacent response domain that controls the expression of the genes located downstream, in most cases at the level of transcription or translation. In this review, we discuss the recent advances and strategies for designing such synthetic riboswitches based on natural or artificial components and readout systems, from trial-and-error approaches to rational design strategies. As the past several years have shown dramatic development in this fascinating field of research, we can give only a limited overview of the basic riboswitch design principles that is far from complete, and we apologize for not being able to consider every successful and interesting approach described in the literature.
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Affiliation(s)
- Maja Etzel
- Institute for Biochemistry, Leipzig University , Brüderstrasse 34, 04103 Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University , Brüderstrasse 34, 04103 Leipzig, Germany
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57
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Min BE, Hwang HG, Lim HG, Jung GY. Optimization of industrial microorganisms: recent advances in synthetic dynamic regulators. ACTA ACUST UNITED AC 2017; 44:89-98. [DOI: 10.1007/s10295-016-1867-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 12/27/2022]
Abstract
Abstract
Production of biochemicals by industrial fermentation using microorganisms requires maintaining cellular production capacity, because maximal productivity is economically important. High-productivity microbial strains can be developed using static engineering, but these may not maintain maximal productivity throughout the culture period as culture conditions and cell states change dynamically. Additionally, economic reasons limit heterologous protein expression using inducible promoters to prevent metabolic burden for commodity chemical and biofuel production. Recently, synthetic and systems biology has been used to design genetic circuits, precisely controlling gene expression or influencing genetic behavior toward a desired phenotype. Development of dynamic regulators can maintain cellular phenotype in a maximum production state in response to factors including cell concentration, oxygen, temperature, pH, and metabolites. Herein, we introduce dynamic regulators of industrial microorganism optimization and discuss metabolic flux fine control by dynamic regulators in response to metabolites or extracellular stimuli, robust production systems, and auto-induction systems using quorum sensing.
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Affiliation(s)
- Byung Eun Min
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Hwang
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Lim
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Gyoo Yeol Jung
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
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58
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Design and Construction of Generalizable RNA-Protein Hybrid Controllers by Level-Matched Genetic Signal Amplification. Cell Syst 2016; 3:549-562.e7. [PMID: 27840078 DOI: 10.1016/j.cels.2016.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 05/21/2016] [Accepted: 10/10/2016] [Indexed: 12/30/2022]
Abstract
For synthetic biology applications, protein-based transcriptional genetic controllers are limited in terms of orthogonality, modularity, and portability. Although ribozyme-based switches can address these issues, their current two-stage architectures and limited dynamic range hinder their broader incorporation into systems-level genetic controllers. Here, we address these challenges by implementing an RNA-protein hybrid controller with a three-stage architecture that introduces a transcription-based amplifier between an RNA sensor and a protein actuator. To facilitate the construction of these more complex circuits, we use a model-guided strategy to efficiently match the activities of stages. The presence of the amplifier enabled the three-stage controller to have up to 200-fold higher gene expression than its two-stage counterpart and made it possible to implement higher-order controllers, such as multilayer Boolean logic and feedback systems. The modularity inherent in the three-stage architecture along with the sensing flexibility of RNA devices presents a generalizable framework for designing and building sophisticated genetic control systems.
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59
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Biofuel metabolic engineering with biosensors. Curr Opin Chem Biol 2016; 35:150-158. [PMID: 27768949 DOI: 10.1016/j.cbpa.2016.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 11/21/2022]
Abstract
Metabolic engineering offers the potential to renewably produce important classes of chemicals, particularly biofuels, at an industrial scale. DNA synthesis and editing techniques can generate large pathway libraries, yet identifying the best variants is slow and cumbersome. Traditionally, analytical methods like chromatography and mass spectrometry have been used to evaluate pathway variants, but such techniques cannot be performed with high throughput. Biosensors - genetically encoded components that actuate a cellular output in response to a change in metabolite concentration - are therefore a promising tool for rapid and high-throughput evaluation of candidate pathway variants. Applying biosensors can also dynamically tune pathways in response to metabolic changes, improving balance and productivity. Here, we describe the major classes of biosensors and briefly highlight recent progress in applying them to biofuel-related metabolic pathway engineering.
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60
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Functional mining of transporters using synthetic selections. Nat Chem Biol 2016; 12:1015-1022. [DOI: 10.1038/nchembio.2189] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 07/28/2016] [Indexed: 12/11/2022]
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61
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Skjoedt ML, Snoek T, Kildegaard KR, Arsovska D, Eichenberger M, Goedecke TJ, Rajkumar AS, Zhang J, Kristensen M, Lehka BJ, Siedler S, Borodina I, Jensen MK, Keasling JD. Engineering prokaryotic transcriptional activators as metabolite biosensors in yeast. Nat Chem Biol 2016; 12:951-958. [DOI: 10.1038/nchembio.2177] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 06/30/2016] [Indexed: 01/30/2023]
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62
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Wang Y, Beal PA. Probing RNA recognition by human ADAR2 using a high-throughput mutagenesis method. Nucleic Acids Res 2016; 44:9872-9880. [PMID: 27614075 PMCID: PMC5175354 DOI: 10.1093/nar/gkw799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 08/30/2016] [Accepted: 08/31/2016] [Indexed: 01/05/2023] Open
Abstract
Adenosine deamination is one of the most prevalent post-transcriptional modifications in mRNA. In humans, ADAR1 and ADAR2 catalyze this modification and their malfunction correlates with disease. Recently our laboratory reported crystal structures of the human ADAR2 deaminase domain bound to duplex RNA revealing a protein loop that binds the RNA on the 5′ side of the modification site. This 5′ binding loop appears to be one contributor to substrate specificity differences between ADAR family members. In this study, we endeavored to reveal detailed structure–activity relationships in this loop to advance our understanding of RNA recognition by ADAR2. To achieve this goal, we established a high-throughput mutagenesis approach which allows rapid screening of ADAR variants in single yeast cells and provides quantitative evaluation for enzymatic activity. Using this approach, we determined the importance of specific amino acids at 19 different positions in the ADAR2 5′ binding loop and revealed six residues that provide essential structural elements supporting the fold of the loop and key RNA-binding functional groups. This work provided new insight into RNA recognition by ADAR2 and established a new tool for defining structure–function relationships in ADAR reactions.
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Affiliation(s)
- Yuru Wang
- Department of Chemistry, University of California, One Shields Ave, Davis, CA 95616, USA
| | - Peter A Beal
- Department of Chemistry, University of California, One Shields Ave, Davis, CA 95616, USA
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63
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Kushwaha M, Rostain W, Prakash S, Duncan JN, Jaramillo A. Using RNA as Molecular Code for Programming Cellular Function. ACS Synth Biol 2016; 5:795-809. [PMID: 26999422 DOI: 10.1021/acssynbio.5b00297] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
RNA is involved in a wide-range of important molecular processes in the cell, serving diverse functions: regulatory, enzymatic, and structural. Together with its ease and predictability of design, these properties can lead RNA to become a useful handle for biological engineers with which to control the cellular machinery. By modifying the many RNA links in cellular processes, it is possible to reprogram cells toward specific design goals. We propose that RNA can be viewed as a molecular programming language that, together with protein-based execution platforms, can be used to rewrite wide ranging aspects of cellular function. In this review, we catalogue developments in the use of RNA parts, methods, and associated computational models that have contributed to the programmability of biology. We discuss how RNA part repertoires have been combined to build complex genetic circuits, and review recent applications of RNA-based parts and circuitry. We explore the future potential of RNA engineering and posit that RNA programmability is an important resource for firmly establishing an era of rationally designed synthetic biology.
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Affiliation(s)
- Manish Kushwaha
- Warwick
Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry, CV4 7AL, U.K
| | - William Rostain
- Warwick
Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry, CV4 7AL, U.K
- iSSB, Genopole,
CNRS, UEVE, Université Paris-Saclay, Évry, France
| | - Satya Prakash
- Warwick
Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry, CV4 7AL, U.K
| | - John N. Duncan
- Warwick
Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry, CV4 7AL, U.K
| | - Alfonso Jaramillo
- Warwick
Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry, CV4 7AL, U.K
- iSSB, Genopole,
CNRS, UEVE, Université Paris-Saclay, Évry, France
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64
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Engineering a microbial platform for de novo biosynthesis of diverse methylxanthines. Metab Eng 2016; 38:191-203. [PMID: 27519552 DOI: 10.1016/j.ymben.2016.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/24/2016] [Accepted: 08/09/2016] [Indexed: 11/20/2022]
Abstract
Engineered microbial biosynthesis of plant natural products can support manufacturing of complex bioactive molecules and enable discovery of non-naturally occurring derivatives. Purine alkaloids, including caffeine (coffee), theophylline (antiasthma drug), theobromine (chocolate), and other methylxanthines, play a significant role in pharmacology and food chemistry. Here, we engineered the eukaryotic microbial host Saccharomyces cerevisiae for the de novo biosynthesis of methylxanthines. We constructed a xanthine-to-xanthosine conversion pathway in native yeast central metabolism to increase endogenous purine flux for the production of 7-methylxanthine, a key intermediate in caffeine biosynthesis. Yeast strains were further engineered to produce caffeine through expression of several enzymes from the coffee plant. By expressing combinations of different N-methyltransferases, we were able to demonstrate re-direction of flux to an alternate pathway and develop strains that support the production of diverse methylxanthines. We achieved production of 270μg/L, 61μg/L, and 3700μg/L of caffeine, theophylline, and 3-methylxanthine, respectively, in 0.3-L bench-scale batch fermentations. The constructed strains provide an early platform for de novo production of methylxanthines and with further development will advance the discovery and synthesis of xanthine derivatives.
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65
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Rugbjerg P, Genee HJ, Jensen K, Sarup-Lytzen K, Sommer MOA. Molecular Buffers Permit Sensitivity Tuning and Inversion of Riboswitch Signals. ACS Synth Biol 2016; 5:632-8. [PMID: 27138234 PMCID: PMC4949582 DOI: 10.1021/acssynbio.5b00213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Predictable integration
of foreign biological signals and parts
remains a key challenge in the systematic engineering of synthetic
cellular actuations, and general methods to improve signal transduction
and sensitivity are needed. To address this problem we modeled and
built a molecular signal buffer network in Saccharomyces cerevisiae inspired by chemical pH buffer systems. The molecular buffer system
context-insulates a riboswitch enabling synthetic control of colony
formation and modular signal manipulations. The riboswitch signal
is relayed to a transcriptional activation domain of a split transcription
factor, while interacting DNA-binding domains mediate the transduction
of signal and form an interacting molecular buffer. The molecular
buffer system enables modular signal inversion through integration
with repressor modules. Further, tuning of input sensitivity was achieved
through perturbation of the buffer pair ratio guided by a mathematical
model. Such buffered signal tuning networks will be useful for domestication
of RNA-based sensors enabling tunable outputs and library-wide selections
for drug discovery and metabolic engineering.
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Affiliation(s)
- Peter Rugbjerg
- Novo Nordisk Foundation Center
for Biosustainability, Technical University of Denmark, Kogle Allé
6, DK-2970 Hørsholm, Denmark
| | - Hans Jasper Genee
- Novo Nordisk Foundation Center
for Biosustainability, Technical University of Denmark, Kogle Allé
6, DK-2970 Hørsholm, Denmark
| | - Kristian Jensen
- Novo Nordisk Foundation Center
for Biosustainability, Technical University of Denmark, Kogle Allé
6, DK-2970 Hørsholm, Denmark
| | - Kira Sarup-Lytzen
- Novo Nordisk Foundation Center
for Biosustainability, Technical University of Denmark, Kogle Allé
6, DK-2970 Hørsholm, Denmark
| | - Morten Otto Alexander Sommer
- Novo Nordisk Foundation Center
for Biosustainability, Technical University of Denmark, Kogle Allé
6, DK-2970 Hørsholm, Denmark
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66
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Abstract
Bacterial genomes encode the biosynthetic potential to produce hundreds of thousands of complex molecules with diverse applications, from medicine to agriculture and materials. Accessing these natural products promises to reinvigorate drug discovery pipelines and provide novel routes to synthesize complex chemicals. The pathways leading to the production of these molecules often comprise dozens of genes spanning large areas of the genome and are controlled by complex regulatory networks with some of the most interesting molecules being produced by non-model organisms. In this Review, we discuss how advances in synthetic biology--including novel DNA construction technologies, the use of genetic parts for the precise control of expression and for synthetic regulatory circuits--and multiplexed genome engineering can be used to optimize the design and synthesis of pathways that produce natural products.
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67
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Hwang C, Carothers JM. Label-free selection of RNA aptamers for metabolic engineering. Methods 2016; 106:37-41. [PMID: 27339940 DOI: 10.1016/j.ymeth.2016.06.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/15/2016] [Accepted: 06/19/2016] [Indexed: 01/18/2023] Open
Abstract
RNA aptamers can be assembled into genetic regulatory devices that sense and respond to levels of specific cellular metabolites and thus serve an integral part of designing dynamic control into engineered metabolic pathways. Here, we describe a practical method for generating specific and high affinity aptamers to enable the wider use of in vitro selection and a broader application of aptamers for metabolic engineering. Conventional selection methods involving either radioactive labeling of RNA or the use of label-free methods such as SPR to track aptamer enrichment require resources that are not widely accessible to research groups. We present a label-free selection method that uses small volume spectrophotometers to track RNA enrichment paired with previously characterized affinity chromatography methods. Borrowing techniques used in solid phase peptide synthesis, we present an approach for immobilizing a wide range of metabolites to an amino PEGA matrix. As an illustration, we detail laboratory techniques employed to generate aptamers that bind p-aminophenylalanine, a metabolic precursor for bio-based production of plastics and the pristinamycin family of antibiotics. We focused on the development of methods for ligand immobilization, selection via affinity chromatography, and nucleic acid quantification that can be performed with common laboratory equipment.
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Affiliation(s)
- Chuhern Hwang
- Departments of Chemical Engineering and Bioengineering, Molecular Engineering and Sciences Institute, and Center for Synthetic Biology, University of Washington, Seattle, WA 98195, United States
| | - James M Carothers
- Departments of Chemical Engineering and Bioengineering, Molecular Engineering and Sciences Institute, and Center for Synthetic Biology, University of Washington, Seattle, WA 98195, United States.
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68
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Wang Z, Cirino PC. New and improved tools and methods for enhanced biosynthesis of natural products in microorganisms. Curr Opin Biotechnol 2016; 42:159-168. [PMID: 27284635 DOI: 10.1016/j.copbio.2016.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 12/28/2022]
Abstract
Engineering efficient biosynthesis of natural products in microorganisms requires optimizing gene expression levels to balance metabolite flux distributions and to minimize accumulation of toxic intermediates. Such metabolic optimization is challenged with identifying the right gene targets, and then determining and achieving appropriate gene expression levels. After decades of having a relatively limited set of gene regulation tools available, metabolic engineers are recently enjoying an ever-growing repertoire of more precise and tunable gene expression platforms. Here we review recent applications of natural and designed transcriptional and translational regulatory machinery for engineering biosynthesis of natural products in microorganisms. Customized trans-acting RNAs (sgRNA, asRNA and sRNA), along with appropriate accessory proteins, are allowing for unparalleled tuning of gene expression. Meanwhile metabolite-responsive transcription factors and riboswitches have been implemented in strain screening and evolution, and in dynamic gene regulation. Further refinements and expansions on these platform technologies will circumvent many long-term obstacles in natural products biosynthesis.
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Affiliation(s)
- Zhiqing Wang
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA
| | - Patrick C Cirino
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA.
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69
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Jang S, Lee B, Jeong HH, Jin SH, Jang S, Kim SG, Jung GY, Lee CS. On-chip analysis, indexing and screening for chemical producing bacteria in a microfluidic static droplet array. LAB ON A CHIP 2016; 16:1909-16. [PMID: 27102263 DOI: 10.1039/c6lc00118a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Economic production of chemicals from microbes necessitates development of high-producing strains and an efficient screening technology is crucial to maximize the effect of the most popular strain improvement method, the combinatorial approach. However, high-throughput screening has been limited for assessment of diverse intracellular metabolites at the single-cell level. Herein, we established a screening platform that couples a microfluidic static droplet array (SDA) and an artificial riboswitch to analyse intracellular metabolite concentration from single microbial cells. Using this system, we entrapped single Escherichia coli cells in SDA to measure intracellular l-tryptophan concentrations. It was validated that intracellular l-tryptophan concentration can be evaluated by the fluorescence from the riboswitch. Moreover, high-producing strains were successfully screened from a mutagenized library, exhibiting up to 145% productivity compared to its parental strain. This platform will be widely applicable to strain improvement for diverse metabolites by developing new artificial riboswitches.
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Affiliation(s)
- Sungho Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 790-784, Korea.
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70
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Synthetic Evolution of Metabolic Productivity Using Biosensors. Trends Biotechnol 2016; 34:371-381. [DOI: 10.1016/j.tibtech.2016.02.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 11/23/2022]
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71
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Billingsley JM, DeNicola AB, Tang Y. Technology development for natural product biosynthesis in Saccharomyces cerevisiae. Curr Opin Biotechnol 2016; 42:74-83. [PMID: 26994377 DOI: 10.1016/j.copbio.2016.02.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/23/2022]
Abstract
The explosion of genomic sequence data and the significant advancements in synthetic biology have led to the development of new technologies for natural products discovery and production. Using powerful genetic tools, the yeast Saccharomyces cerevisiae has been engineered as a production host for natural product pathways from bacterial, fungal, and plant species. With an expanding library of characterized genetic parts, biosynthetic pathways can be refactored for optimized expression in yeast. New engineering strategies have enabled the increased production of valuable secondary metabolites by tuning metabolic pathways. Improvements in high-throughput screening methods have facilitated the rapid identification of variants with improved biosynthetic capabilities. In this review, we focus on the molecular tools and engineering strategies that have recently empowered heterologous natural product biosynthesis.
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Affiliation(s)
- John M Billingsley
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, United States
| | - Anthony B DeNicola
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, United States
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, United States; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, United States.
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72
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McKeague M, Wong RS, Smolke CD. Opportunities in the design and application of RNA for gene expression control. Nucleic Acids Res 2016; 44:2987-99. [PMID: 26969733 PMCID: PMC4838379 DOI: 10.1093/nar/gkw151] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 02/29/2016] [Indexed: 12/15/2022] Open
Abstract
The past decade of synthetic biology research has witnessed numerous advances in the development of tools and frameworks for the design and characterization of biological systems. Researchers have focused on the use of RNA for gene expression control due to its versatility in sensing molecular ligands and the relative ease by which RNA can be modeled and designed compared to proteins. We review the recent progress in the field with respect to RNA-based genetic devices that are controlled through small molecule and protein interactions. We discuss new approaches for generating and characterizing these devices and their underlying components. We also highlight immediate challenges, future directions and recent applications of synthetic RNA devices in engineered biological systems.
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Affiliation(s)
- Maureen McKeague
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Remus S Wong
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Christina D Smolke
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
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73
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Abstract
A central challenge in the field of metabolic engineering is the efficient identification of a metabolic pathway genotype that maximizes specific productivity over a robust range of process conditions. Here we review current methods for optimizing specific productivity of metabolic pathways in living cells. New tools for library generation, computational analysis of pathway sequence-flux space, and high-throughput screening and selection techniques are discussed.
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Affiliation(s)
- Justin R Klesmith
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Timothy A Whitehead
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA; Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA
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74
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Ma KC, Perli SD, Lu TK. Foundations and Emerging Paradigms for Computing in Living Cells. J Mol Biol 2016; 428:893-915. [DOI: 10.1016/j.jmb.2016.02.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/13/2016] [Accepted: 02/15/2016] [Indexed: 01/11/2023]
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75
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Gu P, Su T, Qi Q. Novel technologies provide more engineering strategies for amino acid-producing microorganisms. Appl Microbiol Biotechnol 2016; 100:2097-105. [PMID: 26754821 DOI: 10.1007/s00253-015-7276-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/20/2015] [Accepted: 12/23/2015] [Indexed: 10/22/2022]
Abstract
Traditionally, amino acid-producing strains were obtained by random mutagenesis and subsequent selection. With the development of genetic and metabolic engineering techniques, various microorganisms with high amino acid production yields are now constructed by rational design of targeted biosynthetic pathways. Recently, novel technologies derived from systems and synthetic biology have emerged and open a new promising avenue towards the engineering of amino acid production microorganisms. In this review, these approaches, including rational engineering of rate-limiting enzymes, real-time sensing of end-products, pathway optimization on the chromosome, transcription factor-mediated strain improvement, and metabolic modeling and flux analysis, were summarized with regard to their application in microbial amino acid production.
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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
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
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76
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Boock JT, Gupta A, Prather KLJ. Screening and modular design for metabolic pathway optimization. Curr Opin Biotechnol 2015; 36:189-98. [DOI: 10.1016/j.copbio.2015.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/07/2015] [Accepted: 08/10/2015] [Indexed: 11/26/2022]
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77
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Wei KY, Smolke CD. Engineering dynamic cell cycle control with synthetic small molecule-responsive RNA devices. J Biol Eng 2015; 9:21. [PMID: 26594238 PMCID: PMC4654890 DOI: 10.1186/s13036-015-0019-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/27/2015] [Indexed: 01/08/2023] Open
Abstract
Background The cell cycle plays a key role in human health and disease, including development and cancer. The ability to easily and reversibly control the mammalian cell cycle could mean improved cellular reprogramming, better tools for studying cancer, more efficient gene therapy, and improved heterologous protein production for medical or industrial applications. Results We engineered RNA-based control devices to provide specific and modular control of gene expression in response to exogenous inputs in living cells. Specifically, we identified key regulatory nodes that arrest U2-OS cells in the G0/1 or G2/M phases of the cycle. We then optimized the most promising key regulators and showed that, when these optimized regulators are placed under the control of a ribozyme switch, we can inducibly and reversibly arrest up to ~80 % of a cellular population in a chosen phase of the cell cycle. Characterization of the reliability of the final cell cycle controllers revealed that the G0/1 control device functions reproducibly over multiple experiments over several weeks. Conclusions To our knowledge, this is the first time synthetic RNA devices have been used to control the mammalian cell cycle. This RNA platform represents a general class of synthetic biology tools for modular, dynamic, and multi-output control over mammalian cells. Electronic supplementary material The online version of this article (doi:10.1186/s13036-015-0019-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kathy Y Wei
- Department of Bioengineering, Stanford University, 443 Via Ortega, MC 4245, Stanford, CA 94305 USA
| | - Christina D Smolke
- Department of Bioengineering, Stanford University, 443 Via Ortega, MC 4245, Stanford, CA 94305 USA
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78
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Fletcher E, Krivoruchko A, Nielsen J. Industrial systems biology and its impact on synthetic biology of yeast cell factories. Biotechnol Bioeng 2015; 113:1164-70. [PMID: 26524089 DOI: 10.1002/bit.25870] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/01/2015] [Accepted: 10/28/2015] [Indexed: 02/04/2023]
Abstract
Engineering industrial cell factories to effectively yield a desired product while dealing with industrially relevant stresses is usually the most challenging step in the development of industrial production of chemicals using microbial fermentation processes. Using synthetic biology tools, microbial cell factories such as Saccharomyces cerevisiae can be engineered to express synthetic pathways for the production of fuels, biopharmaceuticals, fragrances, and food flavors. However, directing fluxes through these synthetic pathways towards the desired product can be demanding due to complex regulation or poor gene expression. Systems biology, which applies computational tools and mathematical modeling to understand complex biological networks, can be used to guide synthetic biology design. Here, we present our perspective on how systems biology can impact synthetic biology towards the goal of developing improved yeast cell factories. Biotechnol. Bioeng. 2016;113: 1164-1170. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Eugene Fletcher
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden
| | - Anastasia Krivoruchko
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden. .,Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, SE-412 96 Gothenburg, Sweden. .,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2970, Hørsholm, Denmark.
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79
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Peters G, Coussement P, Maertens J, Lammertyn J, De Mey M. Putting RNA to work: Translating RNA fundamentals into biotechnological engineering practice. Biotechnol Adv 2015; 33:1829-44. [PMID: 26514597 DOI: 10.1016/j.biotechadv.2015.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/13/2015] [Accepted: 10/22/2015] [Indexed: 11/19/2022]
Abstract
Synthetic biology, in close concert with systems biology, is revolutionizing the field of metabolic engineering by providing novel tools and technologies to rationally, in a standardized way, reroute metabolism with a view to optimally converting renewable resources into a broad range of bio-products, bio-materials and bio-energy. Increasingly, these novel synthetic biology tools are exploiting the extensive programmable nature of RNA, vis-à-vis DNA- and protein-based devices, to rationally design standardized, composable, and orthogonal parts, which can be scaled and tuned promptly and at will. This review gives an extensive overview of the recently developed parts and tools for i) modulating gene expression ii) building genetic circuits iii) detecting molecules, iv) reporting cellular processes and v) building RNA nanostructures. These parts and tools are becoming necessary armamentarium for contemporary metabolic engineering. Furthermore, the design criteria, technological challenges, and recent metabolic engineering success stories of the use of RNA devices are highlighted. Finally, the future trends in transforming metabolism through RNA engineering are critically evaluated and summarized.
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Affiliation(s)
- Gert Peters
- Centre of Expertise Industrial Biotechnology and Biocatalysis, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Pieter Coussement
- Centre of Expertise Industrial Biotechnology and Biocatalysis, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Jo Maertens
- Centre of Expertise Industrial Biotechnology and Biocatalysis, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Jeroen Lammertyn
- BIOSYST-MeBioS, KU Leuven, Willem de Croylaan 42, 3001 Louvain, Belgium
| | - Marjan De Mey
- Centre of Expertise Industrial Biotechnology and Biocatalysis, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
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80
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Bott M. Need for speed - finding productive mutations using transcription factor-based biosensors, fluorescence-activated cell sorting and recombineering. Microb Biotechnol 2015; 8:8-10. [PMID: 25627839 PMCID: PMC4321356 DOI: 10.1111/1751-7915.12248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Michael Bott
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, D-52428, Germany
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81
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Development of biosensors and their application in metabolic engineering. Curr Opin Chem Biol 2015; 28:1-8. [DOI: 10.1016/j.cbpa.2015.05.013] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/04/2015] [Accepted: 05/14/2015] [Indexed: 01/30/2023]
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82
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Liu D, Evans T, Zhang F. Applications and advances of metabolite biosensors for metabolic engineering. Metab Eng 2015; 31:35-43. [DOI: 10.1016/j.ymben.2015.06.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 06/23/2015] [Indexed: 01/01/2023]
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83
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Liu Y, Li Q, Zheng P, Zhang Z, Liu Y, Sun C, Cao G, Zhou W, Wang X, Zhang D, Zhang T, Sun J, Ma Y. Developing a high-throughput screening method for threonine overproduction based on an artificial promoter. Microb Cell Fact 2015; 14:121. [PMID: 26296345 PMCID: PMC4546291 DOI: 10.1186/s12934-015-0311-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/04/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND L-Threonine is an important amino acid for animal feed. Though the industrial fermentation technology of threonine achieved a very high level, there is still significant room to further improve the industrial strains. The biosensor-based high-throughput screening (HTS) technology has demonstrated its powerful applications. Unfortunately, for most of valuable fine chemicals such as threonine, a HTS system has not been established mainly due to the absence of a suitable biosensor. In this study, we developed a HTS method to gain high-yielding threonine-producing strains. RESULTS Novel threonine sensing promoters including cysJp and cysHp were discovered by proteomic analyses of Escherichia coli in response to extracellular threonine challenges. The HTS method was constructed using a device composed of the fused cysJp and cysHp as a promoter and a linked enhanced green fluorescent protein gene as a reporter. More than 400 strains were selected with fluorescence activated cell sorting technology from a library of 20 million mutants and tested within 1 week. Thirty-four mutants have higher productivities than the starting industrial producer. One mutant produced 17.95 % more threonine in a 5-L jar fermenter. CONCLUSIONS This method should play a functional role for continuous improvement of threonine industry. Additionally, the threonine sensor construction using promoters obtained by proteomics analyses is so convenient that it would be easily extended to develop HTS models for other biochemicals.
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Affiliation(s)
- Ya'nan Liu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, People's Republic of China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Qinggang Li
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Ping Zheng
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Zhidan Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Yongfei Liu
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Cunmin Sun
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Guoqiang Cao
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Wenjuan Zhou
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Xiaowei Wang
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, 211800, People's Republic of China.
| | - Dawei Zhang
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Tongcun Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, People's Republic of China.
| | - Jibin Sun
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Yanhe Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
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84
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Meyer A, Pellaux R, Potot S, Becker K, Hohmann HP, Panke S, Held M. Optimization of a whole-cell biocatalyst by employing genetically encoded product sensors inside nanolitre reactors. Nat Chem 2015. [PMID: 26201745 DOI: 10.1038/nchem.2301] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Microcompartmentalization offers a high-throughput method for screening large numbers of biocatalysts generated from genetic libraries. Here we present a microcompartmentalization protocol for benchmarking the performance of whole-cell biocatalysts. Gel capsules served as nanolitre reactors (nLRs) for the cultivation and analysis of a library of Bacillus subtilis biocatalysts. The B. subtilis cells, which were co-confined with E. coli sensor cells inside the nLRs, converted the starting material cellobiose into the industrial product vitamin B2. Product formation triggered a sequence of reactions in the sensor cells: (1) conversion of B2 into flavin mononucleotide (FMN), (2) binding of FMN by a RNA riboswitch and (3) self-cleavage of RNA, which resulted in (4) the synthesis of a green fluorescent protein (GFP). The intensity of GFP fluorescence was then used to isolate B. subtilis variants that convert cellobiose into vitamin B2 with elevated efficiency. The underlying design principles of the assay are general and enable the development of similar protocols, which ultimately will speed up the optimization of whole-cell biocatalysts.
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Affiliation(s)
- Andreas Meyer
- 1] Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland [2] FGen GmbH, Basel 4057, Switzerland
| | - René Pellaux
- 1] Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland [2] FGen GmbH, Basel 4057, Switzerland
| | | | - Katja Becker
- Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland
| | | | - Sven Panke
- Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland
| | - Martin Held
- Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland
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85
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Cole RH, de Lange N, Gartner ZJ, Abate AR. Compact and modular multicolour fluorescence detector for droplet microfluidics. LAB ON A CHIP 2015; 15:2754-8. [PMID: 26032595 PMCID: PMC4505729 DOI: 10.1039/c5lc00333d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Multicolour fluorescence detection is often necessary in droplet microfluidics, but typical detection systems are complex, bulky, and expensive. We present a compact and modular detection system capable of sub-nanomolar sensitivity utilizing an optical fibre array to encode spectral information recorded by a single photodetector.
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Affiliation(s)
- Russell H. Cole
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, USA
| | - Niek de Lange
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Wageningen, the Netherlands
| | - Zev J. Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, USA
| | - Adam R. Abate
- Department of Bioengineering and Therapeutic Sciences, California Institute for Quantitative Biosciences, University of California, San Francisco, California, USA
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86
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Fehér T, Libis V, Carbonell P, Faulon JL. A Sense of Balance: Experimental Investigation and Modeling of a Malonyl-CoA Sensor in Escherichia coli. Front Bioeng Biotechnol 2015; 3:46. [PMID: 25905101 PMCID: PMC4389729 DOI: 10.3389/fbioe.2015.00046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 03/23/2015] [Indexed: 01/26/2023] Open
Abstract
Production of value-added chemicals in microorganisms is regarded as a viable alternative to chemical synthesis. In the past decade, several engineered pathways producing such chemicals, including plant secondary metabolites in microorganisms have been reported; upscaling their production yields, however, was often challenging. Here, we analyze a modular device designed for sensing malonyl-CoA, a common precursor for both fatty acid and flavonoid biosynthesis. The sensor can be used either for high-throughput pathway screening in synthetic biology applications or for introducing a feedback circuit to regulate production of the desired chemical. Here, we used the sensor to compare the performance of several predicted malonyl-CoA-producing pathways, and validated the utility of malonyl-CoA reductase and malonate-CoA transferase for malonyl-CoA biosynthesis. We generated a second-order dynamic linear model describing the relation of the fluorescence generated by the sensor to the biomass of the host cell representing a filter/amplifier with a gain that correlates with the level of induction. We found the time constants describing filter dynamics to be independent of the level of induction but distinctively clustered for each of the production pathways, indicating the robustness of the sensor. Moreover, by monitoring the effect of the copy-number of the production plasmid on the dose–response curve of the sensor, we managed to coarse-tune the level of pathway expression to maximize malonyl-CoA synthesis. In addition, we provide an example of the sensor’s use in analyzing the effect of inducer or substrate concentrations on production levels. The rational development of models describing sensors, supplemented with the power of high-throughput optimization provide a promising potential for engineering feedback loops regulating enzyme levels to maximize productivity yields of synthetic metabolic pathways.
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Affiliation(s)
- Tamás Fehér
- Institute of Systems and Synthetic Biology, University of Evry Val d'Essonne , Evry , France ; Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences , Szeged , Hungary
| | - Vincent Libis
- Institute of Systems and Synthetic Biology, University of Evry Val d'Essonne , Evry , France ; Paris Diderot University , Paris , France
| | - Pablo Carbonell
- Institute of Systems and Synthetic Biology, University of Evry Val d'Essonne , Evry , France ; Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences, Hospital del Mar Medical Research Institute (IMIM), Universitat Pompeu Fabra , Barcelona , Spain ; SYNBIOCHEM Center, Manchester Institute of Biotechnology, School of Chemistry, University of Manchester , Manchester , UK
| | - Jean-Loup Faulon
- Institute of Systems and Synthetic Biology, University of Evry Val d'Essonne , Evry , France ; SYNBIOCHEM Center, Manchester Institute of Biotechnology, School of Chemistry, University of Manchester , Manchester , UK
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87
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Kowalsky CA, Klesmith JR, Stapleton JA, Kelly V, Reichkitzer N, Whitehead TA. High-resolution sequence-function mapping of full-length proteins. PLoS One 2015; 10:e0118193. [PMID: 25790064 PMCID: PMC4366243 DOI: 10.1371/journal.pone.0118193] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/06/2015] [Indexed: 11/18/2022] Open
Abstract
Comprehensive sequence-function mapping involves detailing the fitness contribution of every possible single mutation to a gene by comparing the abundance of each library variant before and after selection for the phenotype of interest. Deep sequencing of library DNA allows frequency reconstruction for tens of thousands of variants in a single experiment, yet short read lengths of current sequencers makes it challenging to probe genes encoding full-length proteins. Here we extend the scope of sequence-function maps to entire protein sequences with a modular, universal sequence tiling method. We demonstrate the approach with both growth-based selections and FACS screening, offer parameters and best practices that simplify design of experiments, and present analytical solutions to normalize data across independent selections. Using this protocol, sequence-function maps covering full sequences can be obtained in four to six weeks. Best practices introduced in this manuscript are fully compatible with, and complementary to, other recently published sequence-function mapping protocols.
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Affiliation(s)
- Caitlin A. Kowalsky
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Justin R. Klesmith
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
| | - James A. Stapleton
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Vince Kelly
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Nolan Reichkitzer
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Timothy A. Whitehead
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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88
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Lee SW, Oh MK. A synthetic suicide riboswitch for the high-throughput screening of metabolite production in Saccharomyces cerevisiae. Metab Eng 2015; 28:143-150. [DOI: 10.1016/j.ymben.2015.01.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 12/27/2014] [Accepted: 01/07/2015] [Indexed: 01/08/2023]
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89
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Eckdahl TT, Campbell AM, Heyer LJ, Poet JL, Blauch DN, Snyder NL, Atchley DT, Baker EJ, Brown M, Brunner EC, Callen SA, Campbell JS, Carr CJ, Carr DR, Chadinha SA, Chester GI, Chester J, Clarkson BR, Cochran KE, Doherty SE, Doyle C, Dwyer S, Edlin LM, Evans RA, Fluharty T, Frederick J, Galeota-Sprung J, Gammon BL, Grieshaber B, Gronniger J, Gutteridge K, Henningsen J, Isom B, Itell HL, Keffeler EC, Lantz AJ, Lim JN, McGuire EP, Moore AK, Morton J, Nakano M, Pearson SA, Perkins V, Parrish P, Pierson CE, Polpityaarachchige S, Quaney MJ, Slattery A, Smith KE, Spell J, Spencer M, Taye T, Trueblood K, Vrana CJ, Whitesides ET. Programmed evolution for optimization of orthogonal metabolic output in bacteria. PLoS One 2015; 10:e0118322. [PMID: 25714374 PMCID: PMC4340930 DOI: 10.1371/journal.pone.0118322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/13/2015] [Indexed: 11/18/2022] Open
Abstract
Current use of microbes for metabolic engineering suffers from loss of metabolic output due to natural selection. Rather than combat the evolution of bacterial populations, we chose to embrace what makes biological engineering unique among engineering fields - evolving materials. We harnessed bacteria to compute solutions to the biological problem of metabolic pathway optimization. Our approach is called Programmed Evolution to capture two concepts. First, a population of cells is programmed with DNA code to enable it to compute solutions to a chosen optimization problem. As analog computers, bacteria process known and unknown inputs and direct the output of their biochemical hardware. Second, the system employs the evolution of bacteria toward an optimal metabolic solution by imposing fitness defined by metabolic output. The current study is a proof-of-concept for Programmed Evolution applied to the optimization of a metabolic pathway for the conversion of caffeine to theophylline in E. coli. Introduced genotype variations included strength of the promoter and ribosome binding site, plasmid copy number, and chaperone proteins. We constructed 24 strains using all combinations of the genetic variables. We used a theophylline riboswitch and a tetracycline resistance gene to link theophylline production to fitness. After subjecting the mixed population to selection, we measured a change in the distribution of genotypes in the population and an increased conversion of caffeine to theophylline among the most fit strains, demonstrating Programmed Evolution. Programmed Evolution inverts the standard paradigm in metabolic engineering by harnessing evolution instead of fighting it. Our modular system enables researchers to program bacteria and use evolution to determine the combination of genetic control elements that optimizes catabolic or anabolic output and to maintain it in a population of cells. Programmed Evolution could be used for applications in energy, pharmaceuticals, chemical commodities, biomining, and bioremediation.
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Affiliation(s)
- Todd T. Eckdahl
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
- * E-mail:
| | - A. Malcolm Campbell
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Laurie J. Heyer
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Jeffrey L. Poet
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - David N. Blauch
- Department of Chemistry, Davidson College, Davidson, North Carolina, United States of America
| | - Nicole L. Snyder
- Department of Chemistry, Davidson College, Davidson, North Carolina, United States of America
| | - Dustin T. Atchley
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Erich J. Baker
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Micah Brown
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Elizabeth C. Brunner
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Sean A. Callen
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Jesse S. Campbell
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Caleb J. Carr
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - David R. Carr
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Spencer A. Chadinha
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Grace I. Chester
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Josh Chester
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Ben R. Clarkson
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Kelly E. Cochran
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Shannon E. Doherty
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Catherine Doyle
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Sarah Dwyer
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Linnea M. Edlin
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Rebecca A. Evans
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Taylor Fluharty
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Janna Frederick
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Jonah Galeota-Sprung
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Betsy L. Gammon
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Brandon Grieshaber
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Jessica Gronniger
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Katelyn Gutteridge
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Joel Henningsen
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Bradley Isom
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Hannah L. Itell
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Erica C. Keffeler
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Andrew J. Lantz
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Jonathan N. Lim
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Erin P. McGuire
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Alexander K. Moore
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Jerrad Morton
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Meredith Nakano
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Sara A. Pearson
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Virginia Perkins
- Department of Computer Science, Math and Physics, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Phoebe Parrish
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Claire E. Pierson
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Sachith Polpityaarachchige
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Michael J. Quaney
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Abagael Slattery
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Kathryn E. Smith
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Jackson Spell
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Morgan Spencer
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
| | - Telavive Taye
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - Kamay Trueblood
- Department of Biology, Missouri Western State University, Saint Joseph, Missouri, United States of America
| | - Caroline J. Vrana
- Department of Biology, Davidson College, Davidson, North Carolina, United States of America
| | - E. Tucker Whitesides
- Department of Mathematics and Computer Science, Davidson College, Davidson, North Carolina, United States of America
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90
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Stevens JT, Carothers JM. Designing RNA-based genetic control systems for efficient production from engineered metabolic pathways. ACS Synth Biol 2015; 4:107-15. [PMID: 25314371 DOI: 10.1021/sb400201u] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Engineered metabolic pathways can be augmented with dynamic regulatory controllers to increase production titers by minimizing toxicity and helping cells maintain homeostasis. We investigated the potential for dynamic RNA-based genetic control systems to increase production through simulation analysis of an engineered p-aminostyrene (p-AS) pathway in E. coli. To map the entire design space, we formulated 729 unique mechanistic models corresponding to all of the possible control topologies and mechanistic implementations in the system under study. Two thousand sampled simulations were performed for each of the 729 system designs to relate the potential effects of dynamic control to increases in p-AS production (total of 3 × 10(6) simulations). Our analysis indicates that dynamic control strategies employing aptazyme-regulated expression devices (aREDs) can yield >10-fold improvements over static control. We uncovered generalizable trends in successful control architectures and found that highly performing RNA-based control systems are experimentally tractable. Analyzing the metabolic control state space to predict optimal genetic control strategies promises to enhance the design of metabolic pathways.
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Affiliation(s)
- Jason T. Stevens
- Departments of Chemical Engineering and Bioengineering, Molecular Engineering & Sciences Institute, and Center for Synthetic Biology, University of Washington, Seattle, Washington 98195, United States
| | - James M. Carothers
- Departments of Chemical Engineering and Bioengineering, Molecular Engineering & Sciences Institute, and Center for Synthetic Biology, University of Washington, Seattle, Washington 98195, United States
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91
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Liu W, Jiang R. Combinatorial and high-throughput screening approaches for strain engineering. Appl Microbiol Biotechnol 2015; 99:2093-104. [DOI: 10.1007/s00253-015-6400-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/09/2015] [Accepted: 01/10/2015] [Indexed: 12/31/2022]
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92
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Tsai CS, Kwak S, Turner TL, Jin YS. Yeast synthetic biology toolbox and applications for biofuel production. FEMS Yeast Res 2015; 15:1-15. [PMID: 25195615 DOI: 10.1111/1567-1364.12206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/16/2014] [Accepted: 08/31/2014] [Indexed: 01/04/2023] Open
Abstract
Yeasts are efficient biofuel producers with numerous advantages outcompeting bacterial counterparts. While most synthetic biology tools have been developed and customized for bacteria especially for Escherichia coli, yeast synthetic biological tools have been exploited for improving yeast to produce fuels and chemicals from renewable biomass. Here we review the current status of synthetic biological tools and their applications for biofuel production, focusing on the model strain Saccharomyces cerevisiae We describe assembly techniques that have been developed for constructing genes, pathways, and genomes in yeast. Moreover, we discuss synthetic parts for allowing precise control of gene expression at both transcriptional and translational levels. Applications of these synthetic biological approaches have led to identification of effective gene targets that are responsible for desirable traits, such as cellulosic sugar utilization, advanced biofuel production, and enhanced tolerance against toxic products for biofuel production from renewable biomass. Although an array of synthetic biology tools and devices are available, we observed some gaps existing in tool development to achieve industrial utilization. Looking forward, future tool development should focus on industrial cultivation conditions utilizing industrial strains.
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Affiliation(s)
- Ching-Sung Tsai
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Suryang Kwak
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Timothy L Turner
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yong-Su Jin
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA .,Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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93
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Jensen MK, Keasling JD. Recent applications of synthetic biology tools for yeast metabolic engineering. FEMS Yeast Res 2015; 15:1-10. [PMID: 25041737 DOI: 10.1111/1567-1364.12185] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/04/2014] [Accepted: 07/10/2014] [Indexed: 11/29/2022] Open
Abstract
The last 20 years of metabolic engineering has enabled bio-based production of fuels and chemicals from renewable carbon sources using cost-effective bioprocesses. Much of this work has been accomplished using engineered microorganisms that act as chemical factories. Although the time required to engineer microbial chemical factories has steadily decreased, improvement is still needed. Through the development of synthetic biology tools for key microbial hosts, it should be possible to further decrease the development times and improve the reliability of the resulting microorganism. Together with continuous decreases in price and improvements in DNA synthesis, assembly and sequencing, synthetic biology tools will rationalize time-consuming strain engineering, improve control of metabolic fluxes, and diversify screening assays for cellular metabolism. This review outlines some recently developed synthetic biology tools and their application to improve production of chemicals and fuels in yeast. Finally, we provide a perspective for the challenges that lie ahead.
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Affiliation(s)
- Michael K Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Jay D Keasling
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.,Joint BioEnergy Institute, Emeryville, CA, USA.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Chemical and Biomolecular Engineering & Department of Bioengineering University of California, Berkeley, CA, USA
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94
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Trausch JJ, Batey RT. Design of Modular “Plug-and-Play” Expression Platforms Derived from Natural Riboswitches for Engineering Novel Genetically Encodable RNA Regulatory Devices. Methods Enzymol 2015; 550:41-71. [DOI: 10.1016/bs.mie.2014.10.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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95
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Abstract
Computational protein design, a process that searches for mutants with desired improved properties, plays a central role in the conception of many synthetic biology devices including biosensors, bioproduction, or regulation circuits. To that end, a rational workflow for computational protein design is described here consisting of (a) searching in the sequence, structure or chemical spaces for the desired function and associated protein templates; (b) finding the list of potential hot regions to mutate in the parent proteins; and (c) performing in silico screening of mutants with predicted improved properties.
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96
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Si T, Xiao H, Zhao H. Rapid prototyping of microbial cell factories via genome-scale engineering. Biotechnol Adv 2014; 33:1420-32. [PMID: 25450192 DOI: 10.1016/j.biotechadv.2014.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/13/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
Abstract
Advances in reading, writing and editing genetic materials have greatly expanded our ability to reprogram biological systems at the resolution of a single nucleotide and on the scale of a whole genome. Such capacity has greatly accelerated the cycles of design, build and test to engineer microbes for efficient synthesis of fuels, chemicals and drugs. In this review, we summarize the emerging technologies that have been applied, or are potentially useful for genome-scale engineering in microbial systems. We will focus on the development of high-throughput methodologies, which may accelerate the prototyping of microbial cell factories.
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Affiliation(s)
- Tong Si
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Han Xiao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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97
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Xiao H, Bao Z, Zhao H. High Throughput Screening and Selection Methods for Directed Enzyme Evolution. Ind Eng Chem Res 2014; 54:4011-4020. [PMID: 26074668 PMCID: PMC4461044 DOI: 10.1021/ie503060a] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 02/08/2023]
Abstract
Successful
evolutionary enzyme engineering requires a high throughput
screening or selection method, which considerably increases the chance
of obtaining desired properties and reduces the time and cost. In
this review, a series of high throughput screening and selection methods
are illustrated with significant and recent examples. These high throughput
strategies are also discussed with an emphasis on compatibility with
phenotypic analysis during directed enzyme evolution. Lastly, certain
limitations of current methods, as well as future developments, are
briefly summarized.
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Affiliation(s)
- Han Xiao
- Department of Chemical and Biomolecular Engineering, Department of Biochemistry, and Departments of Chemistry and Bioengineering and Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Zehua Bao
- Department of Chemical and Biomolecular Engineering, Department of Biochemistry, and Departments of Chemistry and Bioengineering and Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, Department of Biochemistry, and Departments of Chemistry and Bioengineering and Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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98
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Kennedy AB, Vowles JV, d'Espaux L, Smolke CD. Protein-responsive ribozyme switches in eukaryotic cells. Nucleic Acids Res 2014; 42:12306-21. [PMID: 25274734 PMCID: PMC4231745 DOI: 10.1093/nar/gku875] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genetic devices that directly detect and respond to intracellular concentrations of proteins are important synthetic biology tools, supporting the design of biological systems that target, respond to or alter specific cellular states. Here, we develop ribozyme-based devices that respond to protein ligands in two eukaryotic hosts, yeast and mammalian cells, to regulate the expression of a gene of interest. Our devices allow for both gene-ON and gene-OFF response upon sensing the protein ligand. As part of our design process, we describe an in vitro characterization pipeline for prescreening device designs to identify promising candidates for in vivo testing. The in vivo gene-regulatory activities in the two types of eukaryotic cells correlate with in vitro cleavage activities determined at different physiologically relevant magnesium concentrations. Finally, localization studies with the ligand demonstrate that ribozyme switches respond to ligands present in the nucleus and/or cytoplasm, providing new insight into their mechanism of action. By extending the sensing capabilities of this important class of gene-regulatory device, our work supports the implementation of ribozyme-based devices in applications requiring the detection of protein biomarkers.
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Affiliation(s)
- Andrew B Kennedy
- Department of Bioengineering, 443 Via Ortega, MC 4245 Stanford University, Stanford, CA 94305, USA
| | - James V Vowles
- Division of Chemistry and Chemical Engineering, 1200 E. California Boulevard, MC 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - Leo d'Espaux
- Division of Chemistry and Chemical Engineering, 1200 E. California Boulevard, MC 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christina D Smolke
- Department of Bioengineering, 443 Via Ortega, MC 4245 Stanford University, Stanford, CA 94305, USA
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99
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Redden H, Morse N, Alper HS. The synthetic biology toolbox for tuning gene expression in yeast. FEMS Yeast Res 2014; 15:1-10. [DOI: 10.1111/1567-1364.12188] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/28/2014] [Accepted: 07/15/2014] [Indexed: 02/04/2023] Open
Affiliation(s)
- Heidi Redden
- Department for Molecular Biosciences; The University of Texas at Austin; Austin TX USA
| | - Nicholas Morse
- McKetta Department of Chemical Engineering; The University of Texas at Austin; Austin TX USA
| | - Hal S. Alper
- Department for Molecular Biosciences; The University of Texas at Austin; Austin TX USA
- McKetta Department of Chemical Engineering; The University of Texas at Austin; Austin TX USA
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100
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Frommer J, Appel B, Müller S. Ribozymes that can be regulated by external stimuli. Curr Opin Biotechnol 2014; 31:35-41. [PMID: 25146171 DOI: 10.1016/j.copbio.2014.07.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/30/2014] [Indexed: 12/20/2022]
Abstract
Ribozymes have been known for about 30 years, and nowadays are understood well enough to be turned into useful tools for a number of applications in vitro and in vivo. Allosteric ribozymes switch on and off their activity in response to a specific chemical (ligand) or physical (temperature, light) signal. The possibility of controlling ribozyme activity by external stimuli is of particular relevance for applications in different fields, such as environmental and medicinal diagnostics, molecular computing, control of gene expression and others. Herein, we review recent advances and describe selected examples of addressable ribozymes.
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Affiliation(s)
- Jennifer Frommer
- Ernst Moritz Arndt University Greifswald, Institute for Biochemistry, Felix Hausdorff Str. 4, D-17487 Greifswald, Germany
| | - Bettina Appel
- Ernst Moritz Arndt University Greifswald, Institute for Biochemistry, Felix Hausdorff Str. 4, D-17487 Greifswald, Germany
| | - Sabine Müller
- Ernst Moritz Arndt University Greifswald, Institute for Biochemistry, Felix Hausdorff Str. 4, D-17487 Greifswald, Germany.
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