1
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Widney KA, Yang DD, Rusch LM, Copley SD. CRISPR-Cas9-assisted genome editing in E. coli elevates the frequency of unintended mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.584922. [PMID: 38562785 PMCID: PMC10983943 DOI: 10.1101/2024.03.19.584922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cas-assisted lambda Red recombineering techniques have rapidly become a mainstay of bacterial genome editing. Such techniques have been used to construct both individual mutants and massive libraries to assess the effects of genomic changes. We have found that a commonly used Cas9-assisted editing method results in unintended mutations elsewhere in the genome in 26% of edited clones. The unintended mutations are frequently found over 200 kb from the intended edit site and even over 10 kb from potential off-target sites. We attribute the high frequency of unintended mutations to error-prone polymerases expressed in response to dsDNA breaks introduced at the edit site. Most unintended mutations occur in regulatory or coding regions and thus may have phenotypic effects. Our findings highlight the risks associated with genome editing techniques involving dsDNA breaks in E. coli and likely other bacteria and emphasize the importance of sequencing the genomes of edited cells to ensure the absence of unintended mutations.
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Affiliation(s)
- Karl A. Widney
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Dong-Dong Yang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Leo M. Rusch
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Shelley D. Copley
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
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2
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Kehila D, Tokuriki N. Measuring differential fitness costs and interactions between genetic cassettes using fluorescent spectrophotometry. Appl Environ Microbiol 2024; 90:e0141923. [PMID: 38299817 PMCID: PMC10880626 DOI: 10.1128/aem.01419-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/10/2023] [Indexed: 02/02/2024] Open
Abstract
In this article, we present a method for designing, executing, and analyzing data from a microbial competition experiment. We use fluorescent reporters to label different competing strains and resolve individual growth curves using a fluorescent spectrophotometer. Our comprehensive data analysis pipeline integrates multiple experiments to simultaneously infer sources of variation, extract selection coefficients, and estimate the genetic contributions to fitness for various synthetic genetic cassettes (SGCs). To demonstrate the method, we employ a synthetic biological system based on Escherichia coli. Strains carry 1 of 10 different plasmids and one of three genomically integrated fluorescent markers. All strains are co-cultured to obtain real-time measurements of optical density (total population density) and fluorescence (sub-population densities). We identify challenges in calibrating between fluorescence and density and of fluorescent proteins maturing at different rates. To resolve these issues, we compare two methods of fluorescence calibration and correct for maturation by measuring in vivo maturation times. We provide evidence of genetic interactions occurring between our SGCs and further show how to use our statistical model to test some hypotheses about microbial growth and the costs of protein expression.IMPORTANCEFluorescently labeled co-cultures are becoming increasingly popular. The approach proposed here offers a high standard for experimental design and data analysis to measure selection coefficients and growth rates in competition. Measuring competitive differences is useful in many laboratory studies, allowing for fitness cost-correction of growth rates and ecological interactions and testing hypotheses in synthetic biology. Using time-resolved growth curves, rather than endpoint measurements, for competition assays allows us to construct a detailed scientific model that can be used to ask questions about fine-grained phenomena, such as bacterial growth dynamics, as well as higher-level phenomena, such as the interactions between synthetic cassette expression.
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Affiliation(s)
- Dan Kehila
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nobuhiko Tokuriki
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
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3
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Yang DD, Rusch LM, Widney KA, Morgenthaler AB, Copley SD. Synonymous edits in the Escherichia coli genome have substantial and condition-dependent effects on fitness. Proc Natl Acad Sci U S A 2024; 121:e2316834121. [PMID: 38252823 PMCID: PMC10835057 DOI: 10.1073/pnas.2316834121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
CRISPR-Cas-based genome editing is widely used in bacteria at scales ranging from construction of individual mutants to massively parallel libraries. This procedure relies on guide RNA-directed cleavage of the genome followed by repair with a template that introduces a desired mutation along with synonymous "immunizing" mutations to prevent re-cleavage of the genome after editing. Because the immunizing mutations do not change the protein sequence, they are often assumed to be neutral. However, synonymous mutations can change mRNA structures in ways that alter levels of the encoded proteins. We have tested the assumption that immunizing mutations are neutral by constructing a library of over 50,000 edits that consist of only synonymous mutations in Escherichia coli. Thousands of edits had substantial effects on fitness during growth of E. coli on acetate, a poor carbon source that is toxic at high concentrations. The percentage of high-impact edits varied considerably between genes and at different positions within genes. We reconstructed clones with high-impact edits and found that 69% indeed had significant effects on growth in acetate. Interestingly, fewer edits affected fitness during growth in glucose, a preferred carbon source, suggesting that changes in protein expression caused by synonymous mutations may be most important when an organism encounters challenging conditions. Finally, we showed that synonymous edits can have widespread effects; a synonymous edit at the 5' end of ptsI altered expression of hundreds of genes. Our results suggest that the synonymous immunizing edits introduced during CRISPR-Cas-based genome editing should not be assumed to be innocuous.
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Affiliation(s)
- Dong-Dong Yang
- Department of Molecular, Cellular and Developmental Biology and the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO80309
| | - Leo M. Rusch
- Department of Molecular, Cellular and Developmental Biology and the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO80309
| | - Karl A. Widney
- Department of Molecular, Cellular and Developmental Biology and the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO80309
| | - Andrew B. Morgenthaler
- Department of Molecular, Cellular and Developmental Biology and the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO80309
- Amyris, Inc., Emeryville, CA94608
| | - Shelley D. Copley
- Department of Molecular, Cellular and Developmental Biology and the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO80309
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4
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Collias D, Vialetto E, Yu J, Co K, Almási ÉDH, Rüttiger AS, Achmedov T, Strowig T, Beisel CL. Systematically attenuating DNA targeting enables CRISPR-driven editing in bacteria. Nat Commun 2023; 14:680. [PMID: 36754958 PMCID: PMC9908933 DOI: 10.1038/s41467-023-36283-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Abstract
Bacterial genome editing commonly relies on chromosomal cleavage with Cas nucleases to counter-select against unedited cells. However, editing normally requires efficient recombination and high transformation efficiencies, which are unavailable in most strains. Here, we show that systematically attenuating DNA targeting activity enables RecA-mediated repair in different bacteria, allowing chromosomal cleavage to drive genome editing. Attenuation can be achieved by altering the format or expression strength of guide (g)RNAs; using nucleases with reduced cleavage activity; or engineering attenuated gRNAs (atgRNAs) with disruptive hairpins, perturbed nuclease-binding scaffolds, non-canonical PAMs, or guide mismatches. These modifications greatly increase cell counts and even improve the efficiency of different types of edits for Cas9 and Cas12a in Escherichia coli and Klebsiella oxytoca. We further apply atgRNAs to restore ampicillin sensitivity in Klebsiella pneumoniae, establishing a resistance marker for genetic studies. Attenuating DNA targeting thus offers a counterintuitive means to achieve CRISPR-driven editing across bacteria.
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Affiliation(s)
- Daphne Collias
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany.,Department of Chemical and Biomolecular Engineering, North Carolina State University, 27695, Raleigh, NC, USA
| | - Elena Vialetto
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany
| | - Jiaqi Yu
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany
| | - Khoa Co
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany
| | - Éva D H Almási
- Helmholtz Centre for Infection Research (HZI), 38124, Braunschweig, Germany
| | - Ann-Sophie Rüttiger
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany
| | - Tatjana Achmedov
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany
| | - Till Strowig
- Helmholtz Centre for Infection Research (HZI), 38124, Braunschweig, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Braunschweig, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany. .,Department of Chemical and Biomolecular Engineering, North Carolina State University, 27695, Raleigh, NC, USA. .,Medical Faculty, University of Würzburg, 97080, Würzburg, Germany.
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5
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Li C, Du Y, Zhang T, Wang H, Hou Z, Zhang Y, Cui W, Chen W. "Genetic scissors" CRISPR/Cas9 genome editing cutting-edge biocarrier technology for bone and cartilage repair. Bioact Mater 2022; 22:254-273. [PMID: 36263098 PMCID: PMC9554751 DOI: 10.1016/j.bioactmat.2022.09.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/13/2022] [Accepted: 09/28/2022] [Indexed: 12/02/2022] Open
Abstract
CRISPR/Cas9 is a revolutionary genome editing technology with the tremendous advantages such as precisely targeting/shearing ability, low cost and convenient operation, becoming an efficient and indispensable tool in biological research. As a disruptive technique, CRISPR/Cas9 genome editing has a great potential to realize a future breakthrough in the clinical bone and cartilage repairing as well. This review highlights the research status of CRISPR/Cas9 system in bone and cartilage repair, illustrates its mechanism for promoting osteogenesis and chondrogenesis, and explores the development tendency of CRISPR/Cas9 in bone and cartilage repair to overcome the current limitations.
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Affiliation(s)
- Chao Li
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China,Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, PR China
| | - Yawei Du
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, PR China
| | - Tongtong Zhang
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China
| | - Haoran Wang
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China,Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, PR China
| | - Zhiyong Hou
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China
| | - Yingze Zhang
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China
| | - Wenguo Cui
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, PR China,Corresponding author.
| | - Wei Chen
- Department of Orthopaedics, The Third Hospital of Hebei Medical University, Orthopaedic Research Institution of Hebei Province, NHC Key Laboratory of Intelligent Orthopaedic Equipment, No.139 Ziqiang Road, Shijiazhuang, 050051, PR China,Corresponding author.
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6
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Bubnov DM, Yuzbashev TV, Khozov AA, Melkina OE, Vybornaya TV, Stan GB, Sineoky SP. Robust counterselection and advanced λRed recombineering enable markerless chromosomal integration of large heterologous constructs. Nucleic Acids Res 2022; 50:8947-8960. [PMID: 35920321 PMCID: PMC9410887 DOI: 10.1093/nar/gkac649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/07/2022] [Accepted: 07/20/2022] [Indexed: 11/17/2022] Open
Abstract
Despite advances in bacterial genome engineering, delivery of large synthetic constructs remains challenging in practice. In this study, we propose a straightforward and robust approach for the markerless integration of DNA fragments encoding whole metabolic pathways into the genome. This approach relies on the replacement of a counterselection marker with cargo DNA cassettes via λRed recombineering. We employed a counterselection strategy involving a genetic circuit based on the CI repressor of λ phage. Our design ensures elimination of most spontaneous mutants, and thus provides a counterselection stringency close to the maximum possible. We improved the efficiency of integrating long PCR-generated cassettes by exploiting the Ocr antirestriction function of T7 phage, which completely prevents degradation of unmethylated DNA by restriction endonucleases in wild-type bacteria. The employment of highly restrictive counterselection and ocr-assisted λRed recombineering allowed markerless integration of operon-sized cassettes into arbitrary genomic loci of four enterobacterial species with an efficiency of 50–100%. In the case of Escherichia coli, our strategy ensures simple combination of markerless mutations in a single strain via P1 transduction. Overall, the proposed approach can serve as a general tool for synthetic biology and metabolic engineering in a range of bacterial hosts.
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Affiliation(s)
- Dmitrii M Bubnov
- Bioresource Center Russian National Collection of Industrial Microorganisms (BRC VKPM), State Research Institute for Genetics and Selection of Industrial Microorganisms of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute' - GosNIIgenetika), 1-st Dorozhny pr., 1, Moscow 117545, Russia.,Kurchatov Complex of Genetic Research, NRC 'Kurchatov Institute', Kurchatov Square, 1, Moscow 123098, Russia
| | - Tigran V Yuzbashev
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Andrey A Khozov
- Bioresource Center Russian National Collection of Industrial Microorganisms (BRC VKPM), State Research Institute for Genetics and Selection of Industrial Microorganisms of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute' - GosNIIgenetika), 1-st Dorozhny pr., 1, Moscow 117545, Russia.,Kurchatov Complex of Genetic Research, NRC 'Kurchatov Institute', Kurchatov Square, 1, Moscow 123098, Russia.,Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Lenin's Hills 1-12, Moscow 119234, Russia
| | - Olga E Melkina
- Kurchatov Complex of Genetic Research, NRC 'Kurchatov Institute', Kurchatov Square, 1, Moscow 123098, Russia.,Laboratory of Bacterial Genetics, NRC 'Kurchatov Institute' - GosNIIgenetika, 1-st Dorozhny pr., 1, Moscow 117545, Russia
| | - Tatiana V Vybornaya
- Bioresource Center Russian National Collection of Industrial Microorganisms (BRC VKPM), State Research Institute for Genetics and Selection of Industrial Microorganisms of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute' - GosNIIgenetika), 1-st Dorozhny pr., 1, Moscow 117545, Russia.,Kurchatov Genomic Center, NRC 'Kurchatov Institute' - GosNIIgenetika, 1-st Dorozhny pr., 1, Moscow 117545, Russia
| | - Guy-Bart Stan
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Sergey P Sineoky
- Bioresource Center Russian National Collection of Industrial Microorganisms (BRC VKPM), State Research Institute for Genetics and Selection of Industrial Microorganisms of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute' - GosNIIgenetika), 1-st Dorozhny pr., 1, Moscow 117545, Russia.,Kurchatov Complex of Genetic Research, NRC 'Kurchatov Institute', Kurchatov Square, 1, Moscow 123098, Russia
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7
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Qin Z, Yu S, Liu L, Wang L, Chen J, Zhou J. A SacB-based system for diverse and multiple genome editing in Gluconobacter oxydans. J Biotechnol 2021; 338:31-39. [PMID: 34246659 DOI: 10.1016/j.jbiotec.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022]
Abstract
Gluconobacter oxydans is an important industrial bacterial strain widely used to produce a lot of useful products. However, very few gene editing tools are available for G. oxydans. This study aimed to develop an efficient genome editing method for G. oxydans using SacB as a counter-selectable marker. A plasmid that could express the kanamycin resistance gene in both E. coli and G. oxydans was constructed using the screened shuttle promoter P116. After optimizing the genome editing conditions, the derivative plasmids could be effectively utilized for diverse genome editing, such as gene deletion, insertion, replacement, and in situ modification in G. oxydans WSH-003. In addition, the SacB-based system also achieved multiple gene editing in G. oxydans. Moreover, the genome of the industrial strain G. oxydans WSH-003 was modified and the growth rate and substrate conversion rate of the strain successfully increased using this system. The system could also have potential to be applied in different G. oxydans strains. The process established in this study also provides a reference for constructing genetic tools for many other genetically recalcitrant bacteria.
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Affiliation(s)
- Zhijie Qin
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Shiqin Yu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Li Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Lingling Wang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Jian Chen
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China.
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8
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Escherichia coli as a platform microbial host for systems metabolic engineering. Essays Biochem 2021; 65:225-246. [PMID: 33956149 DOI: 10.1042/ebc20200172] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/19/2022]
Abstract
Bio-based production of industrially important chemicals and materials from non-edible and renewable biomass has become increasingly important to resolve the urgent worldwide issues including climate change. Also, bio-based production, instead of chemical synthesis, of food ingredients and natural products has gained ever increasing interest for health benefits. Systems metabolic engineering allows more efficient development of microbial cell factories capable of sustainable, green, and human-friendly production of diverse chemicals and materials. Escherichia coli is unarguably the most widely employed host strain for the bio-based production of chemicals and materials. In the present paper, we review the tools and strategies employed for systems metabolic engineering of E. coli. Next, representative examples and strategies for the production of chemicals including biofuels, bulk and specialty chemicals, and natural products are discussed, followed by discussion on materials including polyhydroxyalkanoates (PHAs), proteins, and nanomaterials. Lastly, future perspectives and challenges remaining for systems metabolic engineering of E. coli are discussed.
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9
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Li Q, Sun B, Chen J, Zhang Y, Jiang Y, Yang S. A modified pCas/pTargetF system for CRISPR-Cas9-assisted genome editing in Escherichia coli. Acta Biochim Biophys Sin (Shanghai) 2021; 53:620-627. [PMID: 33764372 DOI: 10.1093/abbs/gmab036] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Indexed: 12/14/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)-associated nuclease 9 (Cas9)-based genome editing tool pCas/pTargetF system that we established previously has been widely used in Escherichia coli MG1655. However, this system failed to manipulate the genome of E. coli BL21(DE3), owing to the potential higher leaky transcription of the gRNA-pMB1 specific to pTargetF in this strain. In this study, we modified the pCas/pTargetF system by replacing the promoter of gRNA-pMB1 with a tightly regulated promoter PrhaB, changing the replicon of pCas to a nontemperature-sensitive replicon, adding the sacB gene into pCas, and replacing the original N20-specific sequence of pTargetF with ccdB gene. We call this updated system as pEcCas/pEcgRNA. We found that gRNA-pMB1 indeed showed a slightly higher leaky expression in the pCas/pTargetF system compared with pEcCas/pEcgRNA. We also confirmed that genome editing can successfully be performed in BL21(DE3) by pEcCas/pEcgRNA with high efficiency. The application of pEcCas/pEcgRNA was then expanded to the E. coli B strain BL21 StarTM (DE3), K-12 strains MG1655, DH5α, CGMCC3705, Nissle1917, W strain ATCC9637, and also another species of Enterobacteriaceae, Tatumella citrea DSM13699, without any specific modifications. Finally, the plasmid curing process was optimized to shorten the time from $\sim$60 h to $\sim$32 h. The entire protocol (including plasmid construction, editing, electroporation and mutant verification, and plasmid elimination) took only $\sim$5.5 days per round in the pEcCas/pEcgRNA system, whereas it took $\sim$7.5 days in the pCas/pTargetF system. This study established a faster-acting genome editing tool that can be used in a wider range of E. coli strains and will also be useful for other Enterobacteriaceae species.
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Affiliation(s)
- Qi Li
- College of Life Sciences, Sichuan Normal University, Chengdu 610101, China
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Bingbing Sun
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jun Chen
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yiwen Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Jiang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou 313000, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou 313000, China
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10
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Fenster JA, Eckert CA. High-Throughput Functional Genomics for Energy Production. Curr Opin Biotechnol 2020; 67:7-14. [PMID: 33152605 DOI: 10.1016/j.copbio.2020.09.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/14/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
Functional genomics remains a foundational field for establishing genotype-phenotype relationships that enable strain engineering. High-throughput (HTP) methods accelerate the Design-Build-Test-Learn cycle that currently drives synthetic biology towards a forward engineering future. Trackable mutagenesis techniques including transposon insertion sequencing and CRISPR-Cas-mediated genome editing allow for rapid fitness profiling of a collection, or library, of mutants to discover beneficial mutations. Due to the relative speed of these experiments compared to adaptive evolution experiments, iterative rounds of mutagenesis can be implemented for next-generation metabolic engineering efforts to design complex production and tolerance phenotypes. Additionally, the expansion of these mutagenesis techniques to novel bacteria are opening up industrial microbes that show promise for establishing a bio-based economy.
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Affiliation(s)
- Jacob A Fenster
- Chemical and Biological Engineering, University of Colorado, Boulder CO, United States; Renewable and Sustainable Energy Institute, University of Colorado, Boulder CO, United States
| | - Carrie A Eckert
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder CO, United States; National Renewable Energy Laboratory, Golden CO, United States.
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Pines G, Fankhauser RG, Eckert CA. Predicting Drug Resistance Using Deep Mutational Scanning. Molecules 2020; 25:E2265. [PMID: 32403408 PMCID: PMC7248951 DOI: 10.3390/molecules25092265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/05/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
Drug resistance is a major healthcare challenge, resulting in a continuous need to develop new inhibitors. The development of these inhibitors requires an understanding of the mechanisms of resistance for a critical mass of occurrences. Recent genome editing technologies based on high-throughput DNA synthesis and sequencing may help to predict mutations resulting in resistance by testing large mutagenesis libraries. Here we describe the rationale of this approach, with examples and relevance to drug development and resistance in malaria.
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Affiliation(s)
- Gur Pines
- Department of Entomology, Agricultural Research Organization, Volcani Center, P.O.B 15159, Rishon LeZion 7505101, Israel
| | - Reilly G. Fankhauser
- Department of Dermatology, Oregon Health & Science University, Baird Hall 3225 SW Pavilion Loop, Portland, OR 97239, USA;
| | - Carrie A. Eckert
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, 027 UCB, Boulder, CO 80309, USA
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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