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Liu Q, Zhu J, Liu N, Sun W, Yu B, Niu H, Liu D, Ouyang P, Ying H, Chen Y, Zhao G, Chen T. Type I fimbriae subunit fimA enhances Escherichia coli biofilm formation but affects L-threonine carbon distribution. Front Bioeng Biotechnol 2022; 10:904636. [PMID: 36338119 PMCID: PMC9633679 DOI: 10.3389/fbioe.2022.904636] [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: 06/14/2022] [Accepted: 10/03/2022] [Indexed: 11/22/2022] Open
Abstract
The biofilm (BF) provides favorable growth conditions to cells, which has been exploited in the field of industrial biotechnology. Based on our previous research works on type I fimbriae for the biosynthesis of L-threonine (LT) in Escherichia coli, in this study, a fimA-overexpressing strain was engineered, which improved BF formation under industrial fermentation conditions. The morphological observation and characterization of BF formation were conducted to verify the function of the subunit FimA. However, it was not suitable for repeated-batch immobilized fermentation as the LT titer was not elevated significantly. The underlying molecular mechanisms of BF formation and the LT carbon flux were explored by transcriptomic analysis. The results showed that fimA regulated E. coli BF formation but affected LT carbon distribution. This study will stimulate thoughts about how the fimbriae gene regulated biofilms and amino acid excretion and will bring some consideration and provide a reference for the development of BF-based biomanufacturing processes in E. coli.
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Affiliation(s)
- Qingguo Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- Nanjing Hi-Tech Biological Technology Research Institute Co., Ltd., Nanjing, China
| | - Jiaqing Zhu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Na Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Wenjun Sun
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Bin Yu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Huanqing Niu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Dong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Pingkai Ouyang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Hanjie Ying
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Yong Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Gulin Zhao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- *Correspondence: Tianpeng Chen, ; Gulin Zhao,
| | - Tianpeng Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- *Correspondence: Tianpeng Chen, ; Gulin Zhao,
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2
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Zhang Z, Su W, Bao Y, Huang Q, Ye K, Liu P, Chu X. Modular reconstruction and optimization of the trans-4-hydroxy-L-proline synthesis pathway in Escherichia coli. Microb Cell Fact 2022; 21:159. [PMID: 35953819 PMCID: PMC9367115 DOI: 10.1186/s12934-022-01884-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/26/2022] [Indexed: 11/24/2022] Open
Abstract
Background In recent years, there has been a growing demand for microbial production of trans-4-hydroxy-L-proline (t4Hyp), which is a value-added amino acid and has been widely used in the fields of medicine, food, and cosmetics. In this study, a multivariate modular metabolic engineering approach was used to remove the bottleneck in the synthesis pathway of t4Hyp. Results Escherichia coli t4Hyp synthesis was performed using two modules: a α-ketoglutarate (α-KG) synthesis module (K module) and L-proline synthesis with hydroxylation module (H module). First, α-KG attrition was reduced, and then, L-proline consumption was inhibited. Subsequently, to improve the contribution to proline synthesis with hydroxylation, optimization of gene overexpression, promotor, copy number, and the fusion system was performed. Finally, optimization of the H and K modules was performed in combination to balance metabolic flow. Using the final module H1K4 in a shaking flask culture, 8.80 g/L t4Hyp was produced, which was threefold higher than that produced by the W0 strain. Conclusions These strategies demonstrate that a microbial cell factory can be systematically optimized by modular engineering for efficient production of t4Hyp. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01884-4.
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Affiliation(s)
- Zhenyu Zhang
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China
| | - Weike Su
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China.,School of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China
| | - Yunyun Bao
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China
| | - Qianqian Huang
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China
| | - Kai Ye
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China
| | - Pengfu Liu
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China.
| | - Xiaohe Chu
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, People's Republic of China.
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3
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Saleski TE, Chung MT, Carruthers DN, Khasbaatar A, Kurabayashi K, Lin XN. Optimized gene expression from bacterial chromosome by high-throughput integration and screening. SCIENCE ADVANCES 2021; 7:7/7/eabe1767. [PMID: 33579713 PMCID: PMC7880599 DOI: 10.1126/sciadv.abe1767] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/30/2020] [Indexed: 06/01/2023]
Abstract
Chromosomal integration of recombinant genes is desirable compared with expression from plasmids due to increased stability, reduced cell-to-cell variability, and elimination of the need for antibiotics for plasmid maintenance. Here, we present a new approach for tuning pathway gene expression levels via random integration and high-throughput screening. We demonstrate multiplexed gene integration and expression-level optimization for isobutanol production in Escherichia coli The integrated strains could, with far lower expression levels than plasmid-based expression, produce high titers (10.0 ± 0.9 g/liter isobutanol in 48 hours) and yields (69% of the theoretical maximum). Close examination of pathway expression in the top-performing, as well as other isolates, reveals the complexity of cellular metabolism and regulation, underscoring the need for precise optimization while integrating pathway genes into the chromosome. We expect this method for pathway integration and optimization can be readily extended to a wide range of pathways and chassis to create robust and efficient production strains.
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Affiliation(s)
- Tatyana E Saleski
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Meng Ting Chung
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - David N Carruthers
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Azzaya Khasbaatar
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Katsuo Kurabayashi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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4
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Xu X, Zhong H, Liu W, Tao Y. Extension of Genetic Marker List Using Unnatural Amino Acid System: An Efficient Genomic Modification Strategy in Escherichia coli. Front Bioeng Biotechnol 2020; 8:145. [PMID: 32411679 PMCID: PMC7198746 DOI: 10.3389/fbioe.2020.00145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/12/2020] [Indexed: 11/24/2022] Open
Abstract
Genetic manipulations including chromosome engineering are essential techniques used to restructure cell metabolism. Lambda/Red (λ/Red)-mediated recombination is the most commonly applied approach for chromosomal modulation in Escherichia coli. However, the efficiency of this method is significantly hampered by the laborious removal of the selectable markers. To overcome the problem, the integration helper plasmid was constructed, pSBC1a-CtR, which contains Red recombinase, Cre recombinase, and exogenous orthogonal aminoacyl-transfer RNA (tRNA) synthetase/tRNA pairs, allows an unnatural amino acid (UAA) to be genetically encoded at the defined site of the antibiotic resistance gene-encoded protein. When UAAs are not in the culture medium, there was no expression in the antibiotic resistance gene-encoded protein. Accordingly, the next procedure of antibiotic gene excising is not needed. To verify this method, poxB gene was knocked out successfully. Furthermore, sequential deletion of three target genes (galR, ptsG, and pgi) was able to generate neurosporene-producing strain marked by high growth rate. Thus, the site-specific incorporation UAA mutagenesis system were used to control and expand the use of conditional selectable marker, and the technique is used to facilitate a rapid continuous genome editing in Escherichia coli.
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Affiliation(s)
- Xinyi Xu
- Engineering Research Center of Molecular and & Neuroimaging, Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.,Chinese Academy of Sciences Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | | | - Weifeng Liu
- Chinese Academy of Sciences Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yong Tao
- Chinese Academy of Sciences Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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5
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Chen T, Liu N, Ren P, Xi X, Yang L, Sun W, Yu B, Ying H, Ouyang P, Liu D, Chen Y. Efficient Biofilm-Based Fermentation Strategies for L-Threonine Production by Escherichia coli. Front Microbiol 2019; 10:1773. [PMID: 31428070 PMCID: PMC6688125 DOI: 10.3389/fmicb.2019.01773] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/18/2019] [Indexed: 12/03/2022] Open
Abstract
Biofilms provide cells favorable growth conditions, which have been exploited in industrial biotechnological processes. However, industrial application of the biofilm has not yet been reported in Escherichia coli, one of the most important platform strains, though the biofilm has been extensively studied for pathogenic reasons. Here, we engineered E. coli by overexpressing the fimH gene, which successfully enhanced its biofilm formation under industrial aerobic cultivation conditions. Subsequently, a biofilm-based immobilized fermentation strategy was developed. L-threonine production was increased from 10.5 to 14.1 g/L during batch fermentations and further to 17.5 g/L during continuous (repeated-batch) fermentations with enhanced productivities. Molecular basis for the enhanced biofilm formation and L-threonine biosynthesis was also studied by transcriptome analysis. This study goes beyond the conventional research focusing on pathogenic aspects of E. coli biofilm and represents a successful application case of engineered E. coli biofilm to industrial processes.
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Affiliation(s)
- Tianpeng Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Na Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Peifang Ren
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Xun Xi
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Leyun Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Wenjun Sun
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Bin Yu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Hanjie Ying
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
| | - Pingkai Ouyang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
| | - Dong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
| | - Yong Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.,Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
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6
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Enhanced biosynthesis of γ-aminobutyric acid (GABA) in Escherichia coli by pathway engineering. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2018.10.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Ryu YS, Chandran SP, Kim K, Lee SK. Oligo- and dsDNA-mediated genome editing using a tetA dual selection system in Escherichia coli. PLoS One 2017; 12:e0181501. [PMID: 28719630 PMCID: PMC5515457 DOI: 10.1371/journal.pone.0181501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 07/03/2017] [Indexed: 12/26/2022] Open
Abstract
The ability to precisely and seamlessly modify a target genome is needed for metabolic engineering and synthetic biology techniques aimed at creating potent biosystems. Herein, we report on a promising method in Escherichia coli that relies on the insertion of an optimized tetA dual selection cassette followed by replacement of the same cassette with short, single-stranded DNA (oligos) or long, double-stranded DNA and the isolation of recombinant strains by negative selection using NiCl2. This method could be rapidly and successfully used for genome engineering, including deletions, insertions, replacements, and point mutations, without inactivation of the methyl-directed mismatch repair (MMR) system and plasmid cloning. The method we describe here facilitates positive genome-edited recombinants with selection efficiencies ranging from 57 to 92%. Using our method, we increased lycopene production (3.4-fold) by replacing the ribosome binding site (RBS) of the rate-limiting gene (dxs) in the 1-deoxy-D-xylulose-5-phosphate (DXP) biosynthesis pathway with a strong RBS. Thus, this method could be used to achieve scarless, proficient, and targeted genome editing for engineering E. coli strains.
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Affiliation(s)
- Young Shin Ryu
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Sathesh-Prabu Chandran
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Kyungchul Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Sung Kuk Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
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8
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Hook C, Samsonov V, Ublinskaya A, Kuvaeva T, Andreeva E, Gorbacheva L, Stoynova N. A novel approach for Escherichia coli genome editing combining in vivo cloning and targeted long-length chromosomal insertion. J Microbiol Methods 2016; 130:83-91. [DOI: 10.1016/j.mimet.2016.08.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/18/2016] [Accepted: 08/23/2016] [Indexed: 02/06/2023]
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9
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L-Tryptophan Production in Escherichia coli Improved by Weakening the Pta-AckA Pathway. PLoS One 2016; 11:e0158200. [PMID: 27348810 PMCID: PMC4922666 DOI: 10.1371/journal.pone.0158200] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/13/2016] [Indexed: 11/24/2022] Open
Abstract
Acetate accumulation during the fermentation process of Escherichia coli FB-04, an L-tryptophan production strain, is detrimental to L-tryptophan production. In an initial attempt to reduce acetate formation, the phosphate acetyltransferase gene (pta) from E. coli FB-04 was deleted, forming strain FB-04(Δpta). Unfortunately, FB-04(Δpta) exhibited a growth defect. Therefore, pta was replaced with a pta variant (pta1) from E. coli CCTCC M 2016009, forming strain FB-04(pta1). Pta1 exhibits lower catalytic capacity and substrate affinity than Pta because of a single amino acid substitution (Pro69Leu). FB-04(pta1) lacked the growth defect of FB-04(Δpta) and showed improved fermentation performance. Strain FB-04(pta1) showed a 91% increase in L-tryptophan yield in flask fermentation experiments, while acetate production decreased by 35%, compared with its parent FB-04. Throughout the fed-batch fermentation process, acetate accumulation by FB-04(pta1) was slower than that by FB-04. The final L-tryptophan titer of FB-04(pta1) reached 44.0 g/L, representing a 15% increase over that of FB-04. Metabolomics analysis showed that the pta1 genomic substitution slightly decreased carbon flux through glycolysis and significantly increased carbon fluxes through the pentose phosphate and common aromatic pathways. These results indicate that this strategy enhances L-tryptophan production and decreases acetate accumulation during the L-tryptophan fermentation process.
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10
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Tokunaga A, Anai H, Hanada K. Mechanisms of gene targeting in higher eukaryotes. Cell Mol Life Sci 2016; 73:523-33. [PMID: 26507245 PMCID: PMC11108335 DOI: 10.1007/s00018-015-2073-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/14/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
Abstract
Targeted genome modifications using techniques that alter the genomic information of interest have contributed to multiple studies in both basic and applied biology. Traditionally, in gene targeting, the target-site integration of a targeting vector by homologous recombination is used. However, this strategy has several technical problems. The first problem is the extremely low frequency of gene targeting, which makes obtaining recombinant clones an extremely labor intensive task. The second issue is the limited number of biomaterials to which gene targeting can be applied. Traditional gene targeting hardly occurs in most of the human adherent cell lines. However, a new approach using designer nucleases that can introduce site-specific double-strand breaks in genomic DNAs has increased the efficiency of gene targeting. This new method has also expanded the number of biomaterials to which gene targeting could be applied. Here, we summarize various strategies for target gene modification, including a comparison of traditional gene targeting with designer nucleases.
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Affiliation(s)
- Akinori Tokunaga
- The Tokunaga Laboratory, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan
- Section of Physiology, Department of Integrative Aging Neuroscience, National Center for Geriatrics and Gerontology (NCGG), 7-430, Morioka-cho, Obu, Aichi, 474-8511, Japan
| | - Hirofumi Anai
- Clinical Engineering Research Center, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan
| | - Katsuhiro Hanada
- Clinical Engineering Research Center, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan.
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11
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Wang Y, Zhang C, Gong T, Zuo Z, Zhao F, Fan X, Yang C, Song C. An upp-based markerless gene replacement method for genome reduction and metabolic pathway engineering in Pseudomonas mendocina NK-01 and Pseudomonas putida KT2440. J Microbiol Methods 2015; 113:27-33. [DOI: 10.1016/j.mimet.2015.03.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 11/25/2022]
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12
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Generation of an attenuated strain oral vaccine candidate using a novel double selection platform in Escherichia coli. Appl Microbiol Biotechnol 2014; 99:855-67. [PMID: 25301580 DOI: 10.1007/s00253-014-6099-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
Abstract
Live attenuated bacteria delivered orally are interesting tools for mucosal immunization. The objective of this study was to construct a novel counter-selection platform based on an attenuated wild-type Escherichia coli (E. coli) strain and to utilize it for the delivery of LTR192G-STaA13Q fusion protein as an oral vaccine. First, a counter-selectable marker, namely, PRPL-Kil, was inserted into an attenuated wild-type E. coli strain through the use of the red and G-DOC homologous recombination systems to construct the counter-selection platform, and PRPL-Kil was subsequently replaced by the LT192-STa13 fusion gene to construct the oral vaccine O142 (yaiT::LT192-STa13) (ER-A). Subsequently, BALB/c mice were orogastrically inoculated with ER-A. Our results showed that ER-A could induce the production of specific IgA and IgG against fimbriae (F41) and enterotoxins (LT and STa), with neutralizing activity in BALB/c mice. In addition, assays of cellular immune responses showed that the stimulation index (SI) values of immunized mice were significantly higher than those of control mice (P<0.05), and revealed a marked shift toward Th2-mediated immunity. These findings suggest that ER-A is a suitable candidate for an oral vaccine strain to protect animals from enter toxigenic Escherichia coli (ETEC) infection.
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13
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Grudniak AM, Pawlak K, Bartosik K, Wolska KI. Physiological consequences of mutations in the htpG heat shock gene of Escherichia coli. Mutat Res 2013; 745-746:1-5. [PMID: 23618614 DOI: 10.1016/j.mrfmmm.2013.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 04/12/2013] [Accepted: 04/17/2013] [Indexed: 10/26/2022]
Abstract
Mutation of the heat shock gene, htpG, causes severe defects of several cellular functions in Escherichia coli. A null htpG mutant constructed by gene replacement was impaired in the biosynthesis and secretion of several enzymes, and in biofilm formation and proteolysis. A significant decrease in the activity of β-lactamase in the ΔhtpG mutant was observed at 42°C. The alkaline phosphatase activity in sonicates of cells propagated at this raised temperature was lower in the ΔhtpG mutant than in the wild-type strain. The ability of the ΔhtpG mutant to degrade abnormal proteins was also impaired compared with the wild-type, but was increased at 42°C. Assays based on bioluminescence and crystal violet staining demonstrated that biofilm formation was diminished in the ΔhtpG mutant at the elevated temperature. All these defects can be complemented upon introducing htpG wild allele.
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Affiliation(s)
- Anna M Grudniak
- Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
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