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Mahdizade Ari M, Dadgar L, Elahi Z, Ghanavati R, Taheri B. Genetically Engineered Microorganisms and Their Impact on Human Health. Int J Clin Pract 2024; 2024:6638269. [PMID: 38495751 PMCID: PMC10944348 DOI: 10.1155/2024/6638269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 11/20/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
The emergence of antibiotic-resistant strains, the decreased effectiveness of conventional therapies, and the side effects have led researchers to seek a safer, more cost-effective, patient-friendly, and effective method that does not develop antibiotic resistance. With progress in synthetic biology and genetic engineering, genetically engineered microorganisms effective in treatment, prophylaxis, drug delivery, and diagnosis have been developed. The present study reviews the types of genetically engineered bacteria and phages, their impacts on diseases, cancer, and metabolic and inflammatory disorders, the biosynthesis of these modified strains, the route of administration, and their effects on the environment. We conclude that genetically engineered microorganisms can be considered promising candidates for adjunctive treatment of diseases and cancers.
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Affiliation(s)
- Marzie Mahdizade Ari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | - Leila Dadgar
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Elahi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | | | - Behrouz Taheri
- Department of Biotechnology, School of Medicine, Ahvaz Jundishapour University of medical Sciences, Ahvaz, Iran
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2
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Duan J, Yuan B, Jia F, Li X, Chen C, Li G. Development of an Efficient and Seamless Genetic Manipulation Method for Xenorhabdus and Its Application for Enhancing the Production of Fabclavines. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:274-283. [PMID: 38109418 DOI: 10.1021/acs.jafc.3c04136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Xenorhabdus can produce numerous natural products, but their development has been hampered by the lack of a seamless genetic manipulation method. In this study, we compared several lethal genes and determined the sacB gene as the most effective counter-selection marker and then established a dual selection/counter-selection system by integrating neo and sacB genes into one cassette. This provides an efficient and seamless genetic manipulation method for Xenorhabdus. Using this method, DNA fragments ranging from 205 to 47,788 bp in length were seamlessly knocked out or replaced with impressively high positive rates of 80 to 100% in Xenorhabdus budapestensis XBD8. In addition, the method was successfully applied with good efficiency (45-100%) in Xenorhabdus nematophila CB6. To further validate the method, different constitutive promoters were used to replace the native fclC promoter in a batch experiment. The positivity rate remained consistently high, at 46.3%. In comparison to WT XBD8, the recombinant strain MX14 demonstrated a significant increase in the production of fabclavine 7 and fabclavine 8 by 4.97-fold and 3.22-fold, respectively, while the overall production of fabclavines was enhanced by 3.52-fold.
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Affiliation(s)
- Jiaqi Duan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Baoming Yuan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fenglian Jia
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaohui Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chang Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Beijing Green Agricultural Science and Technology Group Co., Ltd, Beijing 100193, China
| | - Guangyue Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-Product Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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3
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Thomason LC, Costantino N, Li X, Court DL. Recombineering: Genetic Engineering in Escherichia coli Using Homologous Recombination. Curr Protoc 2023; 3:e656. [PMID: 36779782 PMCID: PMC10037674 DOI: 10.1002/cpz1.656] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The bacterial chromosome and bacterial plasmids can be engineered in vivo by homologous recombination using either PCR products or synthetic double-stranded DNA (dsDNA) or single-stranded DNA as substrates. Multiple linear dsDNA molecules can be assembled into an intact plasmid. The technology of recombineering is possible because bacteriophage-encoded recombination proteins efficiently recombine sequences with homologies as short as 35 to 50 bases. Recombineering allows DNA sequences to be inserted or deleted without regard to the location of restriction sites and can also be used in combination with CRISPR/Cas targeting systems. © 2023 Wiley Periodicals LLC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. Basic Protocol: Making electrocompetent cells and transforming with linear DNA Support Protocol 1: Selection/counter-selections for genome engineering Support Protocol 2: Creating and screening for oligo recombinants by PCR Support Protocol 3: Other methods of screening for unselected recombinants Support Protocol 4: Curing recombineering plasmids containing a temperature-sensitive replication function Support Protocol 5: Removal of the prophage by recombineering Alternate Protocol 1: Using CRISPR/Cas9 as a counter-selection following recombineering Alternate Protocol 2: Assembly of linear dsDNA fragments into functional plasmids Alternate Protocol 3: Retrieval of alleles onto a plasmid by gap repair Alternate Protocol 4: Modifying multicopy plasmids with recombineering Support Protocol 6: Screening for unselected plasmid recombinants Alternate Protocol 5: Recombineering with an intact λ prophage Alternate Protocol 6: Targeting an infecting λ phage with the defective prophage strains.
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Affiliation(s)
- Lynn C. Thomason
- Molecular Control and Genetics Section, RNA Biology Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
| | - Nina Costantino
- formerly with Molecular Control and Genetics Section, RNA Biology Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
| | - Xintian Li
- Armata Pharmaceuticals, 4503 Glencoe Avenue, Marina del Rey, CA 90292
| | - Donald L. Court
- Emeritus, Molecular Control and Genetics Section, RNA Biology Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
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4
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Baas-Thomas MS, Oehm SB, Ostrov N, Church GM. Characterization of ColE1 Production for Robust tolC Plate Dual-Selection in E. coli. ACS Synth Biol 2022; 11:2009-2014. [PMID: 35666547 PMCID: PMC9208019 DOI: 10.1021/acssynbio.2c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Bacterial selection
is an indispensable tool for E. coli genetic
engineering. Marker genes allow for mutant isolation even
at low editing efficiencies. TolC is an especially
useful E. coli marker: its presence can be selected
for with sodium dodecyl sulfate, while its absence can be selected
for with the bactericidal protein ColE1. However, utilization of this
selection system is greatly limited by the lack of commercially available
ColE1 protein. Here, we provide a simple, plate-based, ColE1 negative-selection
protocol that does not require purification of ColE1. Using agar plates
containing a nonpurified lysate from a ColE1-production strain, we
achieved a stringent negative selection with an escape rate of 10–7. Using this powerful negative-selection assay, we
then performed the scarless deletion of multiple, large genomic loci
(>10 kb), screening only 12 colonies each. We hope this accessible
protocol for ColE1 production will lower the barrier of entry for
any lab that wishes to harness tolC’s dual
selection for genetic engineering.
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Affiliation(s)
| | - Sebastian B Oehm
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Nili Ostrov
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States.,Wyss Institute for Biologically Inspired Engineering, Boston, Massachusetts 02115, United States
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Chen W, Chen R, He L, Wu X. Development and optimization of Lysis gene E as a counter-selection marker with high stringency. Biotechnol J 2022; 17:e2100423. [PMID: 35373931 DOI: 10.1002/biot.202100423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 03/19/2022] [Accepted: 04/01/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Seamless modification of bacterial chromosomes is widely performed in both theoretical and practical research. For this purpose, excellent counter-selection marker genes with high stringency are needed. MAIN METHODS AND MAJOR RESULTS The lysis gene E was first constructed under the control of the PL promoter and the cI857 repressor. At 42°C, it could effectively kill Escherichia coli and seamless modification in this bacterium using E as a counter-selection marker was successfully conducted. It also works in another gram-negative strain, Serratia marcescens, under the control of the Arac/PBAD regulatory system. By combining lysis gene E and kil, the counter-selection frequencies of the PL -kil-sd-E cassette in E. coli reached 4.9 × 10-8 and 3.2 × 10-8 at two test loci, which are very close to frequencies observed with the best counter-selection systems reported, the inducible toxin systems. Under the control of the Arac/PBAD , the counter-selection frequency of PBAD -kil-sd-E in S. marcescens reached the level of 10-7 at four test loci. By expressing the araC gene from plasmid pKDsg-ack, 5- to 17-fold improvements in counter-selection stringency were observed at these loci. A surprisingly low counter-selection frequency of 4.9 × 10-9 was obtained at the marR-1 locus, which reflects the highest stringency for a counter-selection cassette reported thus far. Similarly, at the araB locus of E. coli, the counter-selection frequency of PBAD -kil-sd-E was 3 × 10-9 after introducing plasmid pKDsg-ack. CONCLUSIONS AND IMPLICATIONS We have developed and optimized a new universal counter-selection marker based on lysis gene E. The best counter-selection stringency of this new marker exceeds the inducible toxin system several fold. Our work can also provide inspiration for improving counter-selection stringency based on existing markers. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wei Chen
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, China.,Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Ruyi Chen
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Ling He
- Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Xiaotong Wu
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, China
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Wall DA, Tarrant SP, Wang C, Mills KV, Lennon CW. Intein Inhibitors as Novel Antimicrobials: Protein Splicing in Human Pathogens, Screening Methods, and Off-Target Considerations. Front Mol Biosci 2021; 8:752824. [PMID: 34692773 PMCID: PMC8529194 DOI: 10.3389/fmolb.2021.752824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/24/2021] [Indexed: 01/20/2023] Open
Abstract
Protein splicing is a post-translational process by which an intervening polypeptide, or intein, catalyzes its own removal from the flanking polypeptides, or exteins, concomitant with extein ligation. Although inteins are highly abundant in the microbial world, including within several human pathogens, they are absent in the genomes of metazoans. As protein splicing is required to permit function of essential proteins within pathogens, inteins represent attractive antimicrobial targets. Here we review key proteins interrupted by inteins in pathogenic mycobacteria and fungi, exciting discoveries that provide proof of concept that intein activity can be inhibited and that this inhibition has an effect on the host organism's fitness, and bioanalytical methods that have been used to screen for intein activity. We also consider potential off-target inhibition of hedgehog signaling, given the similarity in structure and function of inteins and hedgehog autoprocessing domains.
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Affiliation(s)
- Diana A Wall
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Seanan P Tarrant
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Chunyu Wang
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States.,Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Christopher W Lennon
- Department of Biological Sciences, Murray State University, Murray, KY, United States
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7
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Arukha AP, Freguia CF, Mishra M, Jha JK, Kariyawasam S, Fanger NA, Zimmermann EM, Fanger GR, Sahay B. Lactococcus lactis Delivery of Surface Layer Protein A Protects Mice from Colitis by Re-Setting Host Immune Repertoire. Biomedicines 2021; 9:1098. [PMID: 34572293 PMCID: PMC8470720 DOI: 10.3390/biomedicines9091098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022] Open
Abstract
Inflammatory bowel disease (IBD) is characterized by gastrointestinal inflammation comprised of Crohn's disease and ulcerative colitis. Centers for Disease Control and Prevention report that 1.3% of the population of the United States (approximately 3 million people) were affected by the disease in 2015, and the number keeps increasing over time. IBD has a multifactorial etiology, from genetic to environmental factors. Most of the IBD treatments revolve around disease management, by reducing the inflammatory signals. We previously identified the surface layer protein A (SlpA) of Lactobacillus acidophilus that possesses anti-inflammatory properties to mitigate murine colitis. Herein, we expressed SlpA in a clinically relevant, food-grade Lactococcus lactis to further investigate and characterize the protective mechanisms of the actions of SlpA. Oral administration of SlpA-expressing L. lactis (R110) mitigated the symptoms of murine colitis. Oral delivery of R110 resulted in a higher expression of IL-27 by myeloid cells, with a synchronous increase in IL-10 and cMAF in T cells. Consistent with murine studies, human dendritic cells exposed to R110 showed exquisite differential gene regulation, including IL-27 transcription, suggesting a shared mechanism between the two species, hence positioning R110 as potentially effective at treating colitis in humans.
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Affiliation(s)
- Ananta Prasad Arukha
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL 32608, USA; (A.P.A.); (M.M.)
- Comparative, Diagnostic and Population Medicine, University of Florida, Gainesville, FL 32608, USA;
| | | | - Meerambika Mishra
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL 32608, USA; (A.P.A.); (M.M.)
| | - Jyoti K. Jha
- Rise Therapeutics, Rockville, MD 20850, USA; (C.F.F.); (J.K.J.); (G.R.F.)
| | - Subhashinie Kariyawasam
- Comparative, Diagnostic and Population Medicine, University of Florida, Gainesville, FL 32608, USA;
| | | | - Ellen M. Zimmermann
- Division of Gastroenterology, University of Florida College of Medicine, Gainesville, FL 32608, USA;
| | - Gary R. Fanger
- Rise Therapeutics, Rockville, MD 20850, USA; (C.F.F.); (J.K.J.); (G.R.F.)
| | - Bikash Sahay
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL 32608, USA; (A.P.A.); (M.M.)
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8
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Griffin ME, Espinosa J, Becker JL, Luo JD, Carroll TS, Jha JK, Fanger GR, Hang HC. Enterococcus peptidoglycan remodeling promotes checkpoint inhibitor cancer immunotherapy. Science 2021; 373:1040-1046. [PMID: 34446607 DOI: 10.1126/science.abc9113] [Citation(s) in RCA: 142] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/27/2021] [Indexed: 12/17/2022]
Abstract
The antitumor efficacy of cancer immunotherapy can correlate with the presence of certain bacterial species within the gut microbiome. However, many of the molecular mechanisms that influence host response to immunotherapy remain elusive. In this study, we show that members of the bacterial genus Enterococcus improve checkpoint inhibitor immunotherapy in mouse tumor models. Active enterococci express and secrete orthologs of the NlpC/p60 peptidoglycan hydrolase SagA that generate immune-active muropeptides. Expression of SagA in nonprotective E. faecalis was sufficient to promote immunotherapy response, and its activity required the peptidoglycan sensor NOD2. Notably, SagA-engineered probiotics or synthetic muropeptides also augmented anti-PD-L1 antitumor efficacy. Taken together, our data suggest that microbiota species with specialized peptidoglycan remodeling activity and muropeptide-based therapeutics may enhance cancer immunotherapy and could be leveraged as next-generation adjuvants.
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Affiliation(s)
- Matthew E Griffin
- Departments of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.,Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA.,Bioinformatics Resource Center, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA.,Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA.,Departments of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Juliel Espinosa
- Departments of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.,Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Jessica L Becker
- Departments of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.,Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Ji-Dung Luo
- Bioinformatics Resource Center, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Thomas S Carroll
- Bioinformatics Resource Center, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Jyoti K Jha
- Rise Therapeutics, 1405 Research Blvd. Suite 220, Rockville, MD 20850, USA
| | - Gary R Fanger
- Rise Therapeutics, 1405 Research Blvd. Suite 220, Rockville, MD 20850, USA
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA. .,Departments of Immunology and Microbiology and Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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9
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Repurposing CRISPR-Cas Systems as Genetic Tools for the Enterobacteriales. EcoSal Plus 2021; 9:eESP00062020. [PMID: 34125584 DOI: 10.1128/ecosalplus.esp-0006-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Over the last decade, the study of CRISPR-Cas systems has progressed from a newly discovered bacterial defense mechanism to a diverse suite of genetic tools that have been applied across all domains of life. While the initial applications of CRISPR-Cas technology fulfilled a need to more precisely edit eukaryotic genomes, creative "repurposing" of this adaptive immune system has led to new approaches for genetic analysis of microorganisms, including improved gene editing, conditional gene regulation, plasmid curing and manipulation, and other novel uses. The main objective of this review is to describe the development and current state-of-the-art use of CRISPR-Cas techniques specifically as it is applied to members of the Enterobacteriales. While many of the applications covered have been initially developed in Escherichia coli, we also highlight the potential, along with the limitations, of this technology for expanding the availability of genetic tools in less-well-characterized non-model species, including bacterial pathogens.
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10
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Garewal N, Goyal N, Pathania S, Kaur J, Singh K. Gauging the trends of pseudogenes in plants. Crit Rev Biotechnol 2021; 41:1114-1129. [PMID: 33993808 DOI: 10.1080/07388551.2021.1901648] [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] [Indexed: 12/21/2022]
Abstract
Pseudogenes, the debilitated parts of ancient genes, were previously scrapped off as junk or discarded genes with no functional significance. Pseudogenes have come under scrutiny for their functionality, since recent studies have unveiled their importance in the regulation of their corresponding parent genes and various biological mechanisms. Despite the enormous occurrence of pseudogenes in plants, the lack of experimental validation has contributed toward their unresolved roles in gene regulation. Contrarily, most of the studies associated with gene regulation have been mainly reported for humans, mice, and other mammalian genomes. Consequently, in order to present a cumulative report on plant-based pseudogenes research, an attempt has been made to assemble multiple studies presenting the pseudogene classification, the prediction and the determination of comparative accuracies of various computational pipelines, and recent trends in analyzing their biological functions, and regulatory mechanisms. This review represents the classical, as well as the recent advances on pseudogene identification and their potential roles in transcriptional regulation, which could possibly invigorate the quality of genome annotation, evolutionary analysis, and complexity surrounding the regulatory pathways in plants. Thus, when the ambiguous boundary girdling the pseudogenes eventually recedes on account of their explicit orchestration role, research in flora would no longer saunter compared to that on fauna.
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Affiliation(s)
- Naina Garewal
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Neetu Goyal
- Department of Biotechnology, Panjab University, Chandigarh, India
| | | | - Jagdeep Kaur
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Kashmir Singh
- Department of Biotechnology, Panjab University, Chandigarh, India
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11
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Chiefari E, Arcidiacono B, Mirabelli M, Brunetti FS, Greco E, Foti DP, Brunetti A. Methods to Study Protein-Binding to Pseudogene Transcripts. Methods Mol Biol 2021; 2324:187-202. [PMID: 34165716 DOI: 10.1007/978-1-0716-1503-4_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
One of the most commonly described biological feature of processed pseudogenes is the ability to influence the expression of their parental coding genes. As evidenced in several studies, the high sequence similarity between these RNA pairs sets up a certain level of competition for posttranscriptional regulators, including, among others, RNA-binding proteins (RBPs). RBPs may affect, positively or negatively, the stability of bound mRNAs, so that, if an overexpressed pseudogene competes with its homologous coding gene, the downstream protein synthesis would change, with potential pathological consequences. Given these premises, a rigorous and comprehensive understanding of interactions between pseudogene-parental gene RNA pairs and RBPs could provide further insights into the biological bases of complex diseases, such as cancer, cardiovascular disease, and type 2 diabetes, identifying novel predictive and/or prognostic biomarkers.Herein, we detail easily adaptable protocols of plasmid-based molecular cloning and RNA-electrophoretic mobility shift assay (EMSA) used in our laboratory for determining the interaction between a cytoplasmatic stabilizing protein (αCP1) and the pseudogene-parental gene RNA pair HMGA1-p /HMGA1. We also offer a general overview of RNA immunoprecipitation procedures and present novel bioinformatic tools for predicting RBPs binding sites on pseudogene transcripts.
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Affiliation(s)
- Eusebio Chiefari
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy
| | - Biagio Arcidiacono
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy
| | - Maria Mirabelli
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy
| | | | - Emanuela Greco
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy
| | - Daniela Patrizia Foti
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy
| | - Antonio Brunetti
- Department of Health Sciences, University of Catanzaro "Magna Græcia", Catanzaro, Italy.
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12
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Thomson NM, Zhang C, Trampari E, Pallen MJ. Creation of Golden Gate constructs for gene doctoring. BMC Biotechnol 2020; 20:54. [PMID: 33028286 PMCID: PMC7542709 DOI: 10.1186/s12896-020-00648-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/21/2020] [Indexed: 11/21/2022] Open
Abstract
Background Gene doctoring is an efficient recombination-based genetic engineering approach to mutagenesis of the bacterial chromosome that combines the λ-Red recombination system with a suicide donor plasmid that is cleaved in vivo to generate linear DNA fragments suitable for recombination. The use of a suicide donor plasmid makes Gene Doctoring more efficient than other recombineering technologies. However, generation of donor plasmids typically requires multiple cloning and screening steps. Results We constructed a simplified acceptor plasmid, called pDOC-GG, for the assembly of multiple DNA fragments precisely and simultaneously to form a donor plasmid using Golden Gate assembly. Successful constructs can easily be identified through blue-white screening. We demonstrated proof of principle by inserting a gene for green fluorescent protein into the chromosome of Escherichia coli. We also provided related genetic parts to assist in the construction of mutagenesis cassettes with a tetracycline-selectable marker. Conclusions Our plasmid greatly simplifies the construction of Gene Doctoring donor plasmids and allows for the assembly of complex, multi-part insertion or deletion cassettes with a free choice of target sites and selection markers. The tools we developed are applicable to gene editing for a wide variety of purposes in Enterobacteriaceae and potentially in other diverse bacterial families.
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Affiliation(s)
- Nicholas M Thomson
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK
| | - Chuanzhen Zhang
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Key Laboratory for Veterinary Drug Development and Safety evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Eleftheria Trampari
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK
| | - Mark J Pallen
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK. .,School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TU, UK. .,School of Veterinary Medicine, University of Surrey, Daphne Jackson Road, Guildford, Surrey, GU2 7AL, UK.
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13
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Jing W, Liu J, Wu S, Chen Q, Li X, Liu Y. Development of a Method for Simultaneous Generation of Multiple Genetic Modification in Salmonella enterica Serovar Typhimurium. Front Genet 2020; 11:563491. [PMID: 33193646 PMCID: PMC7544003 DOI: 10.3389/fgene.2020.563491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/19/2020] [Indexed: 01/29/2023] Open
Abstract
To comprehensively analyze bacterial gene function, it is important to simultaneously generate multiple genetic modifications within the target gene. However, current genetic engineering approaches, which mainly use suicide vector- or λ red homologous recombination-based systems, are tedious and technically difficult to perform. Here, we developed a flexible and easy method to simultaneously construct multiple modifications at the same locus on the Salmonella enterica serovar Typhimurium chromosome. The method combines an efficient seamless assembly system in vitro, red homologous recombination in vivo, and counterselection marker sacB. To test this method, with the seamless assembly system, various modification fragments for target genes cpxR, cpxA, and acrB were rapidly and efficiently constructed in vitro. sacBKan cassettes generated via polymerase chain reaction were inserted into the target loci in the genome of Salmonella Typhimurium strain CVCC541. The resulting pKD46-containing kanamycin-resistant recombinants were selected and used as intermediate strains. Multiple target gene modifications were then carried out simultaneously via allelic exchange using various homologous recombinogenic DNA fragments to replace the sacBKan cassettes in the chromosomes of the intermediate strains. Using this method, we successfully carried out site-directed mutagenesis, seamless deletion, and 3 × FLAG tagging of the target genes. This method can be used in any bacterial species that supports sacB gene activity and λ red-mediated recombination, allowing in-depth functional analysis of bacterial genes.
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Affiliation(s)
- Wenxian Jing
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Juan Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Shanshan Wu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Qiwei Chen
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xuerui Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yongsheng Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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14
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Fels U, Gevaert K, Van Damme P. Bacterial Genetic Engineering by Means of Recombineering for Reverse Genetics. Front Microbiol 2020; 11:548410. [PMID: 33013782 PMCID: PMC7516269 DOI: 10.3389/fmicb.2020.548410] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 08/14/2020] [Indexed: 12/11/2022] Open
Abstract
Serving a robust platform for reverse genetics enabling the in vivo study of gene functions primarily in enterobacteriaceae, recombineering -or recombination-mediated genetic engineering-represents a powerful and relative straightforward genetic engineering tool. Catalyzed by components of bacteriophage-encoded homologous recombination systems and only requiring short ∼40–50 base homologies, the targeted and precise introduction of modifications (e.g., deletions, knockouts, insertions and point mutations) into the chromosome and other episomal replicons is empowered. Furthermore, by its ability to make use of both double- and single-stranded linear DNA editing substrates (e.g., PCR products or oligonucleotides, respectively), lengthy subcloning of specific DNA sequences is circumvented. Further, the more recent implementation of CRISPR-associated endonucleases has allowed for more efficient screening of successful recombinants by the selective purging of non-edited cells, as well as the creation of markerless and scarless mutants. In this review we discuss various recombineering strategies to promote different types of gene modifications, how they are best applied, and their possible pitfalls.
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Affiliation(s)
- Ursula Fels
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.,VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Petra Van Damme
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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15
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Güell M. Conjugative Assembly Genome Engineering (CAGE). Methods Mol Biol 2020; 2075:399-409. [PMID: 31584178 DOI: 10.1007/978-1-4939-9877-7_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Conjugative assembly genome engineering (CAGE) enables the transfer of large chromosomal regions from a donor to a recipient. Specific regions of the donor chromosome can be introduced in the recipient genome by the directed insertion of an origin of transfer and two selection cassettes. Multiple paired CAGE experiments can be combined to generate chimeric chromosomes from different donor strains.
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Affiliation(s)
- Marc Güell
- Departament de Ciències Experimentals i de la Salut, Universidad Pompeu Fabra, Barcelona, Spain.
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16
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Fu L, Xie C, Jin Z, Tu Z, Han L, Jin M, Xiang Y, Zhang A. The prokaryotic Argonaute proteins enhance homology sequence-directed recombination in bacteria. Nucleic Acids Res 2019; 47:3568-3579. [PMID: 30698806 PMCID: PMC6468240 DOI: 10.1093/nar/gkz040] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 02/01/2023] Open
Abstract
Argonaute proteins are present and conserved in all domains of life. Recently characterized prokaryotic Argonaute proteins (pAgos) participates in host defense by DNA interference. Here, we report that the Natronobacterium gregoryi Argonaute (NgAgo) enhances gene insertions or deletions in Pasteurella multocida and Escherichia coli at efficiencies of 80–100%. Additionally, the effects are in a homologous arms-dependent but guide DNA- and potential enzyme activity-independent manner. Interestingly, such effects were also observed in other pAgos fragments including Thermus thermophilus Argonaute (TtAgo), Aquifex aeolicus Argonaute (AaAgo) and Pyrococcus furiosus Argonaute (PfAgo). The underlying mechanism of the NgAgo system is a positive selection process mainly through its PIWI-like domain interacting with recombinase A (recA) to enhance recA-mediated DNA strand exchange. Our study reveals a novel system for enhancing homologous sequence-guided gene editing in bacteria.
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Affiliation(s)
- Lei Fu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Caiyun Xie
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zehua Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zizhuo Tu
- Shanghai East Hospital, School of Life Sciences and Technology, Advanced Institute of Translational Medicine, Tongji University, Shanghai 200092, China
| | - Li Han
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China.,Key Laboratory of Development of Veterinary Diagnostic Products (Ministry of Agriculture), International Research Center for Animal Disease (Ministry of Science and Technology), Wuhan, Hubei 430070, China
| | - Yaozu Xiang
- Shanghai East Hospital, School of Life Sciences and Technology, Advanced Institute of Translational Medicine, Tongji University, Shanghai 200092, China
| | - Anding Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China.,Key Laboratory of Development of Veterinary Diagnostic Products (Ministry of Agriculture), International Research Center for Animal Disease (Ministry of Science and Technology), Wuhan, Hubei 430070, China
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17
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Chen W, Li Y, Wu G, Zhao L, Lu L, Wang P, Zhou J, Cao C, Li S. Simple and efficient genome recombineering using kil counter-selection in Escherichia coli. J Biotechnol 2019; 294:58-66. [PMID: 30768999 DOI: 10.1016/j.jbiotec.2019.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 01/04/2019] [Accepted: 01/19/2019] [Indexed: 01/01/2023]
Abstract
Seamless modification of the Escherichia coli genome using positive selection / negative selection is widely used in metabolic engineering and functional genome analysis. Some excellent negative selection systems have been reported, of which tetA-sacB and inducible toxins system are prominent. To expand the existing negative selection toolkit, we constructed a new negative selection marker system based on kil gene of lambda prophage. The selection stringency of kil was measured and compared with the most widely used counter-selection gene, sacB, at the lacI, ack, and dbpa loci using different E. coli strains. At all these loci of tested strains, the selection stringency of kil significantly exceeds that of sacB by 2- to 28-fold. When dsDNA fragments were employed for recombination, the efficiency for isolating the correct recombinant of kil was significantly higher than that of sacB. This new negative selection system does not require special media or extended incubation time. However, our system cannot be used in host strains containing temperature-sensitive kil gene. A Red system providing plasmid without kil gene is recommended for use together with our system. Our counter-selection system is expected to be an addition to the engineering arsenal of E. coli.
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Affiliation(s)
- Wei Chen
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; Beijing Institute of Biotechnology, Beijing 100850, China
| | - Yujuan Li
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Guangjin Wu
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Lingfeng Zhao
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Li Lu
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Peng Wang
- Beijing Institute of Biotechnology, Beijing 100850, China
| | - Jianguang Zhou
- Beijing Institute of Biotechnology, Beijing 100850, China
| | - Cheng Cao
- Beijing Institute of Biotechnology, Beijing 100850, China.
| | - Shanhu Li
- Beijing Institute of Biotechnology, Beijing 100850, China.
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18
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Ji X, Lu P, van der Veen S. Development of a dual-antimicrobial counterselection method for markerless genetic engineering of bacterial genomes. Appl Microbiol Biotechnol 2019; 103:1465-1474. [PMID: 30607491 DOI: 10.1007/s00253-018-9565-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 11/28/2022]
Abstract
Markerless genetic engineering of bacterial genomes is commonly performed by two-step homologous recombination methods using vectors carrying flanking regions of the target gene for site-specific vector integration and counterselection markers to provide positive selection pressure on the second recombination step resulting in vector excision. Here, we provide the proof-of-principle of a novel counterselection method that exploits antagonistic activities between bactericidal and bacteriostatic antibiotics and which can provide selection pressure on the second recombination step by selective killing of bacteria retaining the antibiotic selection marker. This method was optimized for the bacterial pathogens Listeria monocytogenes and Neisseria meningitidis by screening for antagonistic activities between the bactericidal aminoglycosides kanamycin, streptomycin, and gentamicin in combination with the bacteriostatic antibiotics chloramphenicol and erythromycin. The largest difference in selective killing of both L. monocytogenes and N. meningitidis containing an antibiotic selection marker versus wild-type bacteria was observed for the combination of erythromycin, gentamicin, and ermC as antibiotic selection marker. Therefore, this combination was used to generate two markerless deletion mutants for both L. monocytogenes and N. meningitidis. After applying the dual-antimicrobial selection pressure on cultures during the second recombination step, surviving colonies were replica plated on agar with and without erythromycin. On average, 12-13% of the randomly selected bacterial colonies had lost the selection marker due to a second recombination event and approximately half of these colonies were the desired markerless in-frame deletion mutants. Therefore, this method proved to be easy and fast and should be applicable to a wide variety of bacterial species.
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Affiliation(s)
- Xuemeng Ji
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ping Lu
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Stijn van der Veen
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China. .,Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China. .,State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
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19
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Wang C, Tan Z, Niu B, Tsang KY, Tai A, Chan WCW, Lo RLK, Leung KKH, Dung NWF, Itoh N, Zhang MQ, Chan D, Cheah KSE. Inhibiting the integrated stress response pathway prevents aberrant chondrocyte differentiation thereby alleviating chondrodysplasia. eLife 2018; 7:37673. [PMID: 30024379 PMCID: PMC6053305 DOI: 10.7554/elife.37673] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/05/2018] [Indexed: 12/16/2022] Open
Abstract
The integrated stress response (ISR) is activated by diverse forms of cellular stress, including endoplasmic reticulum (ER) stress, and is associated with diseases. However, the molecular mechanism(s) whereby the ISR impacts on differentiation is incompletely understood. Here, we exploited a mouse model of Metaphyseal Chondrodysplasia type Schmid (MCDS) to provide insight into the impact of the ISR on cell fate. We show the protein kinase RNA-like ER kinase (PERK) pathway that mediates preferential synthesis of ATF4 and CHOP, dominates in causing dysplasia by reverting chondrocyte differentiation via ATF4-directed transactivation of Sox9. Chondrocyte survival is enabled, cell autonomously, by CHOP and dual CHOP-ATF4 transactivation of Fgf21. Treatment of mutant mice with a chemical inhibitor of PERK signaling prevents the differentiation defects and ameliorates chondrodysplasia. By preventing aberrant differentiation, titrated inhibition of the ISR emerges as a rationale therapeutic strategy for stress-induced skeletal disorders.
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Affiliation(s)
- Cheng Wang
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Zhijia Tan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Ben Niu
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Kwok Yeung Tsang
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Andrew Tai
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Wilson C W Chan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Rebecca L K Lo
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Keith K H Leung
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Nelson W F Dung
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Nobuyuki Itoh
- Graduate School of Pharmaceutical Sciences, University of Kyoto, Kyoto, Japan
| | - Michael Q Zhang
- Department of Biological Sciences, Center for Systems Biology, The University of Texas at Dallas, Richardson, United States.,MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, China
| | - Danny Chan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
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20
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Freed E, Fenster J, Smolinski SL, Walker J, Henard CA, Gill R, Eckert CA. Building a genome engineering toolbox in nonmodel prokaryotic microbes. Biotechnol Bioeng 2018; 115:2120-2138. [PMID: 29750332 DOI: 10.1002/bit.26727] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/02/2018] [Accepted: 03/10/2018] [Indexed: 12/26/2022]
Abstract
The realization of a sustainable bioeconomy requires our ability to understand and engineer complex design principles for the development of platform organisms capable of efficient conversion of cheap and sustainable feedstocks (e.g., sunlight, CO2 , and nonfood biomass) into biofuels and bioproducts at sufficient titers and costs. For model microbes, such as Escherichia coli, advances in DNA reading and writing technologies are driving the adoption of new paradigms for engineering biological systems. Unfortunately, microbes with properties of interest for the utilization of cheap and renewable feedstocks, such as photosynthesis, autotrophic growth, and cellulose degradation, have very few, if any, genetic tools for metabolic engineering. Therefore, it is important to develop "design rules" for building a genetic toolbox for novel microbes. Here, we present an overview of our current understanding of these rules for the genetic manipulation of prokaryotic microbes and the available genetic tools to expand our ability to genetically engineer nonmodel systems.
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Affiliation(s)
- Emily Freed
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Jacob Fenster
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | | | - Julie Walker
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Calvin A Henard
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO
| | - Ryan Gill
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | - Carrie A Eckert
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
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21
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Bai H, Deng A, Liu S, Cui D, Qiu Q, Wang L, Yang Z, Wu J, Shang X, Zhang Y, Wen T. A Novel Tool for Microbial Genome Editing Using the Restriction-Modification System. ACS Synth Biol 2018; 7:98-106. [PMID: 28968490 DOI: 10.1021/acssynbio.7b00254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Scarless genetic manipulation of genomes is an essential tool for biological research. The restriction-modification (R-M) system is a defense system in bacteria that protects against invading genomes on the basis of its ability to distinguish foreign DNA from self DNA. Here, we designed an R-M system-mediated genome editing (RMGE) technique for scarless genetic manipulation in different microorganisms. For bacteria with Type IV REase, an RMGE technique using the inducible DNA methyltransferase gene, bceSIIM (RMGE-bceSIIM), as the counter-selection cassette was developed to edit the genome of Escherichia coli. For bacteria without Type IV REase, an RMGE technique based on a restriction endonuclease (RMGE-mcrA) was established in Bacillus subtilis. These techniques were successfully used for gene deletion and replacement with nearly 100% counter-selection efficiencies, which were higher and more stable compared to conventional methods. Furthermore, precise point mutation without limiting sites was achieved in E. coli using RMGE-bceSIIM to introduce a single base mutation of A128C into the rpsL gene. In addition, the RMGE-mcrA technique was applied to delete the CAN1 gene in Saccharomyces cerevisiae DAY414 with 100% counter-selection efficiency. The effectiveness of the RMGE technique in E. coli, B. subtilis, and S. cerevisiae suggests the potential universal usefulness of this technique for microbial genome manipulation.
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Affiliation(s)
- Hua Bai
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Aihua Deng
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuwen Liu
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Di Cui
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qidi Qiu
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Laiyou Wang
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhao Yang
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Wu
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiuling Shang
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Zhang
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tingyi Wen
- CAS
Key Laboratory of Pathogenic Microbiology and Immunology, Institute
of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- Savaid
Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
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22
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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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23
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Characterization of Inducible ccdB Gene as a Counterselectable Marker in Escherichia coli Recombineering. Curr Microbiol 2017; 74:961-964. [PMID: 28573338 DOI: 10.1007/s00284-017-1273-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/27/2017] [Indexed: 02/04/2023]
Abstract
Recombineering is a homologous-based DNA cloning and modification technique. Recombineering-mediated chromosomal gene knock-in usually involves a selectable/counterselectable cassette. Though a variety of selectable/counterselectable cassettes were developed; however, a specifically designed gene deletion strain or minimal medium is often required. Herein, we describe a novel selectable/counterselectable cassette Plac-ccdB-aacC1 in which aacC1 (gentamicin resistance gene) is used as the selectable marker for the homologous arm-flanked cassette knock-in, while the IPTG inducible ccdB gene is used as the counterselectable marker for chromosomal gene knock-in. The counterselection is achieved via supplementing 1 mM IPTG in the LB agar medium. An oligonucleotide designed to evade the mismatch repair system was utilized to engineer an Escherichia coli DH10B-derived gyrA462 strain that was used to as the host for the plasmid harboring the Plac-ccdB-aacC1 cassette. By using the Plac-ccdB-aacC1 cassette, a linear-linear homologous recombination (LLHR) system was generated by knocking a 6.2 kb araC-PBAD-redγ-recET-recA DNA fragment into the E. coli DH10B chromosome. The functional of the LLHR recombineering system was characterized by cloning of the target DNA from PCR product as well as from the genomic DNA mixture. The Plac-ccdB-aacC1 cassette will be a useful tool in E. coli recombineering.
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24
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Oesterle S, Wuethrich I, Panke S. Toward Genome-Based Metabolic Engineering in Bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2017; 101:49-82. [PMID: 29050667 DOI: 10.1016/bs.aambs.2017.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Prokaryotes modified stably on the genome are of great importance for production of fine and commodity chemicals. Traditional methods for genome engineering have long suffered from imprecision and low efficiencies, making construction of suitable high-producer strains laborious. Here, we review the recent advances in discovery and refinement of molecular precision engineering tools for genome-based metabolic engineering in bacteria for chemical production, with focus on the λ-Red recombineering and the clustered regularly interspaced short palindromic repeats/Cas9 nuclease systems. In conjunction, they enable the integration of in vitro-synthesized DNA segments into specified locations on the chromosome and allow for enrichment of rare mutants by elimination of unmodified wild-type cells. Combination with concurrently developing improvements in important accessory technologies such as DNA synthesis, high-throughput screening methods, regulatory element design, and metabolic pathway optimization tools has resulted in novel efficient microbial producer strains and given access to new metabolic products. These new tools have made and will likely continue to make a big impact on the bioengineering strategies that transform the chemical industry.
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25
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Wang Y. PlantRGDB: A Database of Plant Retrocopied Genes. PLANT & CELL PHYSIOLOGY 2017; 58:e2. [PMID: 28111365 DOI: 10.1093/pcp/pcw210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/17/2016] [Indexed: 05/26/2023]
Abstract
RNA-based gene duplication, known as retrocopy, plays important roles in gene origination and genome evolution. The genomes of many plants have been sequenced, offering an opportunity to annotate and mine the retrocopies in plant genomes. However, comprehensive and unified annotation of retrocopies in these plants is still lacking. In this study I constructed the PlantRGDB (Plant Retrocopied Gene DataBase), the first database of plant retrocopies, to provide a putatively complete centralized list of retrocopies in plant genomes. The database is freely accessible at http://probes.pw.usda.gov/plantrgdb or http://aegilops.wheat.ucdavis.edu/plantrgdb. It currently integrates 49 plant species and 38,997 retrocopies along with characterization information. PlantRGDB provides a user-friendly web interface for searching, browsing and downloading the retrocopies in the database. PlantRGDB also offers graphical viewer-integrated sequence information for displaying the structure of each retrocopy. The attributes of the retrocopies of each species are reported using a browse function. In addition, useful tools, such as an advanced search and BLAST, are available to search the database more conveniently. In conclusion, the database will provide a web platform for obtaining valuable insight into the generation of retrocopies and will supplement research on gene duplication and genome evolution in plants.
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Affiliation(s)
- Yi Wang
- USDA-ARS, Western Regional Research Center, Crop Improvement and Genetics Research Unit, Albany, CA, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
- USDA-ARS, Plant Gene Expression Center, Albany, CA, USA
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26
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Torres L, Krüger A, Csibra E, Gianni E, Pinheiro VB. Synthetic biology approaches to biological containment: pre-emptively tackling potential risks. Essays Biochem 2016; 60:393-410. [PMID: 27903826 PMCID: PMC5264511 DOI: 10.1042/ebc20160013] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 12/29/2022]
Abstract
Biocontainment comprises any strategy applied to ensure that harmful organisms are confined to controlled laboratory conditions and not allowed to escape into the environment. Genetically engineered microorganisms (GEMs), regardless of the nature of the modification and how it was established, have potential human or ecological impact if accidentally leaked or voluntarily released into a natural setting. Although all evidence to date is that GEMs are unable to compete in the environment, the power of synthetic biology to rewrite life requires a pre-emptive strategy to tackle possible unknown risks. Physical containment barriers have proven effective but a number of strategies have been developed to further strengthen biocontainment. Research on complex genetic circuits, lethal genes, alternative nucleic acids, genome recoding and synthetic auxotrophies aim to design more effective routes towards biocontainment. Here, we describe recent advances in synthetic biology that contribute to the ongoing efforts to develop new and improved genetic, semantic, metabolic and mechanistic plans for the containment of GEMs.
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Affiliation(s)
- Leticia Torres
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K.
| | - Antje Krüger
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Eszter Csibra
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Edoardo Gianni
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Vitor B Pinheiro
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K.
- Birkbeck, Department of Biological Sciences, University of London, Malet Street, WC1E 7HX, U.K
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Evolutionary direction of processed pseudogenes. SCIENCE CHINA-LIFE SCIENCES 2016; 59:839-49. [PMID: 27333782 DOI: 10.1007/s11427-016-5074-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/08/2016] [Indexed: 10/21/2022]
Abstract
While some pseudogenes have been reported to play important roles in gene regulation, little is known about the possible relationship between pseudogene functions and evolutionary process of pseudogenes, or about the forces responsible for the pseudogene evolution. In this study, we characterized human processed pseudogenes in terms of evolutionary dynamics. Our results show that pseudogenes tend to evolve toward: lower GC content, strong dinucleotide bias, reduced abundance of transcription factor binding motifs and short palindromes, and decreased ability to form nucleosomes. We explored possible evolutionary forces that shaped the evolution pattern of pseudogenes, and concluded that mutations in pseudogenes are likely determined, at least partially, by neighbor-dependent mutational bias and recombination-associated selection.
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Abstract
The bacteriophage λ Red homologous recombination system has been studied over the past 50 years as a model system to define the mechanistic details of how organisms exchange DNA segments that share extended regions of homology. The λ Red system proved useful as a system to study because recombinants could be easily generated by co-infection of genetically marked phages. What emerged from these studies was the recognition that replication of phage DNA was required for substantial Red-promoted recombination in vivo, and the critical role that double-stranded DNA ends play in allowing the Red proteins access to the phage DNA chromosomes. In the past 16 years, however, the λ Red recombination system has gained a new notoriety. When expressed independently of other λ functions, the Red system is able to promote recombination of linear DNA containing limited regions of homology (∼50 bp) with the Escherichia coli chromosome, a process known as recombineering. This review explains how the Red system works during a phage infection, and how it is utilized to make chromosomal modifications of E. coli with such efficiency that it changed the nature and number of genetic manipulations possible, leading to advances in bacterial genomics, metabolic engineering, and eukaryotic genetics.
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Affiliation(s)
- Kenan C Murphy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605
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29
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Liu Y, Yang M, Chen J, Yan D, Cheng W, Wang Y, Thygesen A, Chen R, Xing J, Wang Q, Ma Y. PCR-Based Seamless Genome Editing with High Efficiency and Fidelity in Escherichia coli. PLoS One 2016; 11:e0149762. [PMID: 27019283 PMCID: PMC4809717 DOI: 10.1371/journal.pone.0149762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/04/2016] [Indexed: 11/18/2022] Open
Abstract
Efficiency and fidelity are the key obstacles for genome editing toolboxes. In the present study, a PCR-based tandem repeat assisted genome editing (TRAGE) method with high efficiency and fidelity was developed. The design of TRAGE is based on the mechanism of repair of spontaneous double-strand breakage (DSB) via replication fork reactivation. First, cat-sacB cassette flanked by tandem repeat sequence was integrated into target site in chromosome assisted by Red enzymes. Then, for the excision of the cat-sacB cassette, only subculturing is needed. The developed method was successfully applied for seamlessly deleting, substituting and inserting targeted genes using PCR products. The effects of different manipulations including sucrose addition time, subculture times in LB with sucrose and stages of inoculation on the efficiency were investigated. With our recommended procedure, seamless excision of cat-sacB cassette can be realized in 48 h efficiently. We believe that the developed method has great potential for seamless genome editing in E. coli.
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Affiliation(s)
- Yilan Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Maohua Yang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Jinjin Chen
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Daojiang Yan
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Wanwan Cheng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Yanyan Wang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Anders Thygesen
- Center of Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Ruonan Chen
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Jianmin Xing
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
- * E-mail: (JX); (QW)
| | - Qinhong Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
- * E-mail: (JX); (QW)
| | - Yanhe Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
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30
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REPLACR-mutagenesis, a one-step method for site-directed mutagenesis by recombineering. Sci Rep 2016; 6:19121. [PMID: 26750263 PMCID: PMC4707547 DOI: 10.1038/srep19121] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 12/04/2015] [Indexed: 12/22/2022] Open
Abstract
Mutagenesis is an important tool to study gene regulation, model disease-causing mutations and for functional characterisation of proteins. Most of the current methods for mutagenesis involve multiple step procedures. One of the most accurate methods for genetically altering DNA is recombineering, which uses bacteria expressing viral recombination proteins. Recently, the use of in vitro seamless assembly systems using purified enzymes for multiple-fragment cloning as well as mutagenesis is gaining ground. Although these in vitro isothermal reactions are useful when cloning multiple fragments, for site-directed mutagenesis it is unnecessary. Moreover, the use of purified enzymes in vitro is not only expensive but also more inaccurate than the high-fidelity recombination inside bacteria. Here we present a single-step method, named REPLACR-mutagenesis (Recombineering of Ends of linearised PLAsmids after PCR), for creating mutations (deletions, substitutions and additions) in plasmids by in vivo recombineering. REPLACR-mutagenesis only involves transformation of PCR products in bacteria expressing Red/ET recombineering proteins. Modifications in a variety of plasmids up to bacterial artificial chromosomes (BACs; 144 kb deletion) have been achieved by this method. The presented method is more robust, involves fewer steps and is cost-efficient.
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Khetrapal V, Mehershahi K, Rafee S, Chen S, Lim CL, Chen SL. A set of powerful negative selection systems for unmodified Enterobacteriaceae. Nucleic Acids Res 2015; 43:e83. [PMID: 25800749 PMCID: PMC4513841 DOI: 10.1093/nar/gkv248] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 03/10/2015] [Indexed: 12/21/2022] Open
Abstract
Creation of defined genetic mutations is a powerful method for dissecting mechanisms of bacterial disease; however, many genetic tools are only developed for laboratory strains. We have designed a modular and general negative selection strategy based on inducible toxins that provides high selection stringency in clinical Escherichia coli and Salmonella isolates. No strain- or species-specific optimization is needed, yet this system achieves better selection stringency than all previously reported negative selection systems usable in unmodified E. coli strains. The high stringency enables use of negative instead of positive selection in phage-mediated generalized transduction and also allows transfer of alleles between arbitrary strains of E. coli without requiring phage. The modular design should also allow further extension to other bacteria. This negative selection system thus overcomes disadvantages of existing systems, enabling definitive genetic experiments in both lab and clinical isolates of E. coli and other Enterobacteriaceae.
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Affiliation(s)
- Varnica Khetrapal
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074
| | - Kurosh Mehershahi
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074
| | - Shazmina Rafee
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074
| | - Siyi Chen
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074
| | - Chiew Ling Lim
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074
| | - Swaine L Chen
- National University of Singapore, Department of Medicine, Yong Loo Lin School of Medicine, 1E Kent Ridge Road, NUHS Tower Block, Level 10, Singapore 119074 Genome Institute of Singapore, Infectious Diseases Group, 60 Biopolis Street, Genome, #02-01, Singapore 138672
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32
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Wright O, Delmans M, Stan GB, Ellis T. GeneGuard: A modular plasmid system designed for biosafety. ACS Synth Biol 2015; 4:307-16. [PMID: 24847673 DOI: 10.1021/sb500234s] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Synthetic biology applications in biosensing, bioremediation, and biomining envision the use of engineered microbes beyond a contained laboratory. Deployment of such microbes in the environment raises concerns of unchecked cellular proliferation or unwanted spread of synthetic genes. While antibiotic-resistant plasmids are the most utilized vectors for introducing synthetic genes into bacteria, they are also inherently insecure, acting naturally to propagate DNA from one cell to another. To introduce security into bacterial synthetic biology, we here took on the task of completely reformatting plasmids to be dependent on their intended host strain and inherently disadvantageous for others. Using conditional origins of replication, rich-media compatible auxotrophies, and toxin-antitoxin pairs we constructed a mutually dependent host-plasmid platform, called GeneGuard. In this, replication initiators for the R6K or ColE2-P9 origins are provided in trans by a specified host, whose essential thyA or dapA gene is translocated from a genomic to a plasmid location. This reciprocal arrangement is stable for at least 100 generations without antibiotic selection and is compatible for use in LB medium and soil. Toxin genes ζ or Kid are also employed in an auxiliary manner to make the vector disadvantageous for strains not expressing their antitoxins. These devices, in isolation and in concert, severely reduce unintentional plasmid propagation in E. coli and B. subtilis and do not disrupt the intended E. coli host's growth dynamics. Our GeneGuard system comprises several versions of modular cargo-ready vectors, along with their requisite genomic integration cassettes, and is demonstrated here as an efficient vector for heavy-metal biosensors.
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Affiliation(s)
- Oliver Wright
- Centre
for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Mihails Delmans
- Centre
for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Guy-Bart Stan
- Centre
for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Tom Ellis
- Centre
for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
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Tominaga M, Kawai-Noma S, Kawagishi I, Sowa Y, Saito K, Umeno D. Liquid-based iterative recombineering method tolerant to counter-selection escapes. PLoS One 2015; 10:e0119818. [PMID: 25775434 PMCID: PMC4361647 DOI: 10.1371/journal.pone.0119818] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/16/2015] [Indexed: 11/24/2022] Open
Abstract
Selection-based recombineering is a flexible and proven technology to precisely modify bacterial genomes at single base resolution. It consists of two steps of homologous recombination followed by selection/counter-selection. However, the shortage of efficient counter-selectable markers limits the throughput of this method. Additionally, the emergence of ‘selection escapees’ can affect recombinant pools generated through this method, and they must be manually removed at each step of selection-based recombineering. Here, we report a series of efforts to improve the throughput and robustness of selection-based recombineering and to achieve seamless and automatable genome engineering. Using the nucleoside kinase activity of herpes simplex virus thymidine kinase (hsvTK) on the non-natural nucleoside dP, a highly efficient, rapid, and liquid-based counter-selection system was established. By duplicating hsvtk gene, combined with careful control of the population size for the subsequent round, we effectively eliminated selection escapes, enabling seamless and multiple insertions/replacement of gene-size fragments in the chromosome. Four rounds of recombineering could thus be completed in 10 days, requiring only liquid handling and without any need for colony isolation or genotype confirmation. The simplicity and robustness of our method make it broadly accessible for multi-locus chromosomal modifications.
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Affiliation(s)
- Masahiro Tominaga
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Shigeko Kawai-Noma
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Ikuro Kawagishi
- Department of Frontier Bioscience, Hosei University, 3-7-2, Koganei, Tokyo 184-8584, Japan
| | - Yoshiyuki Sowa
- Department of Frontier Bioscience, Hosei University, 3-7-2, Koganei, Tokyo 184-8584, Japan
- Research Center for Micro-Nano Technology, Hosei University, 3-11-15 Midori-cho, Tokyo 184-8584, Japan
| | - Kyoichi Saito
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Daisuke Umeno
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- * E-mail:
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34
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Jeong J, Seo HN, Jung YK, Lee J, Ryu G, Lee W, Kwon E, Ryoo K, Kim J, Cho HY, Cho KM, Park JH, Bang D. Repetitive genomic insertion of gene-sized dsDNAs by targeting the promoter region of a counter-selectable marker. Sci Rep 2015; 5:8712. [PMID: 25736821 PMCID: PMC4348660 DOI: 10.1038/srep08712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/30/2015] [Indexed: 11/18/2022] Open
Abstract
Genome engineering can be used to produce bacterial strains with a wide range of desired phenotypes. However, the incorporation of gene-sized DNA fragments is often challenging due to the intricacy of the procedure, off-target effects, and low insertion efficiency. Here we report a genome engineering method enabling the continuous incorporation of gene-sized double-stranded DNAs (dsDNAs) into the Escherichia coli genome. DNA substrates are inserted without introducing additional marker genes, by synchronously turning an endogenous counter-selectable marker gene ON and OFF. To accomplish this, we utilized λ Red protein-mediated recombination to insert dsDNAs within the promoter region of a counter-selectable marker gene, tolC. By repeatedly switching the marker gene ON and OFF, a number of desired gene-sized dsDNAs can be inserted consecutively. With this method, we successfully inserted approximately 13 kb gene clusters to generate engineered E. coli strains producing 1,4-butanediol (1,4-BDO).
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Affiliation(s)
- Jaehwan Jeong
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Han Na Seo
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Yu Kyung Jung
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea
| | - Jeewon Lee
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Gyuri Ryu
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Wookjae Lee
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Euijin Kwon
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Keunsoo Ryoo
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
| | - Jungyeon Kim
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K
| | - Hwa-Young Cho
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea
| | - Kwang Myung Cho
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea
| | - Jin Hwan Park
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea
| | - Duhee Bang
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
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Excision of unstable artificial gene-specific inverted repeats mediates scar-free gene deletions in Escherichia coli. Appl Biochem Biotechnol 2014; 175:1858-67. [PMID: 25427592 DOI: 10.1007/s12010-014-1402-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/12/2014] [Indexed: 01/13/2023]
Abstract
Inverted repeat and palindromic sequences have the propensity to form non-beta cruciform structures during DNA replication, leading to perturbations within the genome or plasmid replicon. In this study, the tolerance of the Escherichia coli genome to inverted repeat sequences from 25 to 1200 bp was investigated. Genomic inverted repeats were readily created via the homologous insertion of an overlap extension PCR product containing a gene-specific region of the genome together with thyA coding sequence, creating inverted repeat sequences of various lengths flanking the thyA selection marker in the resulting genome. Inverted repeat sequences below 100 bp were stably propagated, while those above and up to 1200 bp were found to be transiently unstable under auxotrophic thymine selection. Excision efficiency improves with increases of the inverted repeat until 600-800 bp, indicating that the genomic stability of inverted repeat sequences is due to secondary structure formation. Its effectiveness of creating precise and scar-free gene deletions was further demonstrated by deleting a number of genes in E. coli. The procedure can be readily adapted for sequence integration and point mutations in E. coli genome. It also has the potential for applications on other bacteria for efficient gene deletions.
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36
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Application of Molecular Approaches for Understanding Foodborne Salmonella Establishment in Poultry Production. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/813275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Salmonellosis in the United States is one of the most costly foodborne diseases. Given that Salmonella can originate from a wide variety of environments, reduction of this organism at all stages of poultry production is critical. Salmonella species can encounter various environmental stress conditions which can dramatically influence their survival and colonization. Current knowledge of Salmonella species metabolism and physiology in relation to colonization is traditionally based on studies conducted primarily with tissue culture and animal infection models. Consequently, while there is some information about environmental signals that control Salmonella growth and colonization, much still remains unknown. Genetic tools for comprehensive functional genomic analysis of Salmonella offer new opportunities for not only achieving a better understanding of Salmonella pathogens but also designing more effective intervention strategies. Now the function(s) of each single gene in the Salmonella genome can be directly assessed and previously unknown genetic factors that are required for Salmonella growth and survival in the poultry production cycle can be elucidated. In particular, delineating the host-pathogen relationships involving Salmonella is becoming very helpful for identifying optimal targeted gene mutagenesis strategies to generate improved vaccine strains. This represents an opportunity for development of novel vaccine approaches for limiting Salmonella establishment in early phases of poultry production. In this review, an overview of Salmonella issues in poultry, a general description of functional genomic technologies, and their specific application to poultry vaccine developments are discussed.
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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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38
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Ma NJ, Moonan DW, Isaacs FJ. Precise manipulation of bacterial chromosomes by conjugative assembly genome engineering. Nat Protoc 2014; 9:2285-300. [PMID: 25188631 PMCID: PMC5568562 DOI: 10.1038/nprot.2014.081] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Conjugative assembly genome engineering (CAGE) is a precise method of genome assembly using conjugation to hierarchically combine distinct genotypes from multiple Escherichia coli strains into a single chimeric genome. CAGE permits large-scale transfer of specified genomic regions between strains without constraints imposed by in vitro manipulations. Strains are assembled in a pairwise manner by establishing a donor strain that harbors conjugation machinery and a recipient strain that receives DNA from the donor. Within strain pairs, targeted placement of a conjugal origin of transfer and selectable markers in donor and recipient genomes enables the controlled transfer and selection of desired donor-recipient chimeric genomes. By design, selectable markers act as genomic anchor points, and they are recycled in subsequent rounds of hierarchical genome transfer. A single round of CAGE can be completed in a week, thus enabling four rounds (hierarchical assembly of 16 strains) of CAGE to be completed in roughly 1 month.
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Affiliation(s)
- Natalie J Ma
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA. [2] Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Daniel W Moonan
- 1] Systems Biology Institute, Yale University, West Haven, Connecticut, USA. [2] Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Farren J Isaacs
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA. [2] Systems Biology Institute, Yale University, West Haven, Connecticut, USA
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Krishnakumar R, Grose C, Haft DH, Zaveri J, Alperovich N, Gibson DG, Merryman C, Glass JI. Simultaneous non-contiguous deletions using large synthetic DNA and site-specific recombinases. Nucleic Acids Res 2014; 42:e111. [PMID: 24914053 PMCID: PMC4132700 DOI: 10.1093/nar/gku509] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toward achieving rapid and large scale genome modification directly in a target organism, we have developed a new genome engineering strategy that uses a combination of bioinformatics aided design, large synthetic DNA and site-specific recombinases. Using Cre recombinase we swapped a target 126-kb segment of the Escherichia coli genome with a 72-kb synthetic DNA cassette, thereby effectively eliminating over 54 kb of genomic DNA from three non-contiguous regions in a single recombination event. We observed complete replacement of the native sequence with the modified synthetic sequence through the action of the Cre recombinase and no competition from homologous recombination. Because of the versatility and high-efficiency of the Cre-lox system, this method can be used in any organism where this system is functional as well as adapted to use with other highly precise genome engineering systems. Compared to present-day iterative approaches in genome engineering, we anticipate this method will greatly speed up the creation of reduced, modularized and optimized genomes through the integration of deletion analyses data, transcriptomics, synthetic biology and site-specific recombination.
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Affiliation(s)
- Radha Krishnakumar
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
| | - Carissa Grose
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
| | - Daniel H Haft
- Bioinformatics, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
| | - Jayshree Zaveri
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
| | - Nina Alperovich
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
| | - Daniel G Gibson
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 4120 Torrey Pines Road, La Jolla, CA 92037, USA Synthetic Genomics Inc., 11149 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Chuck Merryman
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 4120 Torrey Pines Road, La Jolla, CA 92037, USA
| | - John I Glass
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Dr., Rockville, MD 20850, USA
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40
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Dainat J, Pontarotti P. Methods to study the occurrence and the evolution of pseudogenes through a phylogenetic approach. Methods Mol Biol 2014; 1167:87-99. [PMID: 24823773 DOI: 10.1007/978-1-4939-0835-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
During the last few years, the study of pseudogenes has excited enthusiasm, because it has been proven that at least some of them are involved in important biological processes. An accurate detection and analysis of pseudogenes can be achieved using comparative methods, but only the use of phylogenetic tools can provide accurate information about their birth, their evolution and their death, hence about the impact that they have on genes and genomes. Here, phylogenetic methods that allow studying pseudogene history are described.
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Affiliation(s)
- Jacques Dainat
- Evolutionary Biology and Modeling Group, Aix-Marseille Université, LATP - UMR 7353, 3 Place Victor Hugo - Case 19, 13331, Marseille Cedex 3, France,
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41
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High-efficiency scarless genetic modification in Escherichia coli by using lambda red recombination and I-SceI cleavage. Appl Environ Microbiol 2014; 80:3826-34. [PMID: 24747889 DOI: 10.1128/aem.00313-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic modifications of bacterial chromosomes are important for both fundamental and applied research. In this study, we developed an efficient, easy-to-use system for genetic modification of the Escherichia coli chromosome, a two-plasmid method involving lambda Red (λ-Red) recombination and I-SceI cleavage. An intermediate strain is generated by integration of a resistance marker gene(s) and I-SceI recognition sites in or near the target gene locus, using λ-Red PCR targeting. The intermediate strain is transformed with a donor plasmid carrying the target gene fragment with the desired modification flanked by I-SceI recognition sites, together with a bifunctional helper plasmid for λ-Red recombination and I-SceI endonuclease. I-SceI cleavage of the chromosome and the donor plasmid allows λ-Red recombination between chromosomal breaks and linear double-stranded DNA from the donor plasmid. Genetic modifications are introduced into the chromosome, and the placement of the I-SceI sites determines the nature of the recombination and the modification. This method was successfully used for cadA knockout, gdhA knock-in, seamless deletion of pepD, site-directed mutagenesis of the essential metK gene, and replacement of metK with the Rickettsia S-adenosylmethionine transporter gene. This effective method can be used with both essential and nonessential gene modifications and will benefit basic and applied genetic research.
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42
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Thomason LC, Sawitzke JA, Li X, Costantino N, Court DL. Recombineering: genetic engineering in bacteria using homologous recombination. CURRENT PROTOCOLS IN MOLECULAR BIOLOGY 2014; 106:1.16.1-1.16.39. [PMID: 24733238 DOI: 10.1002/0471142727.mb0116s106] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The bacterial chromosome and bacterial plasmids can be engineered in vivo by homologous recombination using PCR products and synthetic oligonucleotides as substrates. This is possible because bacteriophage-encoded recombination proteins efficiently recombine sequences with homologies as short as 35 to 50 bases. Recombineering allows DNA sequences to be inserted or deleted without regard to location of restriction sites. This unit first describes preparation of electrocompetent cells expressing the recombineering functions and their transformation with dsDNA or ssDNA. It then presents support protocols that describe several two-step selection/counter-selection methods of making genetic alterations without leaving any unwanted changes in the targeted DNA, and a method for retrieving onto a plasmid a genetic marker (cloning by retrieval) from the Escherichia coli chromosome or a co-electroporated DNA fragment. Additional protocols describe methods to screen for unselected mutations, removal of the defective prophage from recombineering strains, and other useful techniques.
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Affiliation(s)
- Lynn C Thomason
- Basic Science Program, GRCBL-Molecular Control & Genetics Section, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc, Frederick, Maryland
| | - James A Sawitzke
- Molecular Control and Genetics Section, Gene Regulation and Chromosome Biology, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
| | - Xintian Li
- Molecular Control and Genetics Section, Gene Regulation and Chromosome Biology, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
| | - Nina Costantino
- Molecular Control and Genetics Section, Gene Regulation and Chromosome Biology, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
| | - Donald L Court
- Molecular Control and Genetics Section, Gene Regulation and Chromosome Biology, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland
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43
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Gregg CJ, Lajoie MJ, Napolitano MG, Mosberg JA, Goodman DB, Aach J, Isaacs FJ, Church GM. Rational optimization of tolC as a powerful dual selectable marker for genome engineering. Nucleic Acids Res 2014; 42:4779-90. [PMID: 24452804 PMCID: PMC3985617 DOI: 10.1093/nar/gkt1374] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Selection has been invaluable for genetic manipulation, although counter-selection has historically exhibited limited robustness and convenience. TolC, an outer membrane pore involved in transmembrane transport in E. coli, has been implemented as a selectable/counter-selectable marker, but counter-selection escape frequency using colicin E1 precludes using tolC for inefficient genetic manipulations and/or with large libraries. Here, we leveraged unbiased deep sequencing of 96 independent lineages exhibiting counter-selection escape to identify loss-of-function mutations, which offered mechanistic insight and guided strain engineering to reduce counter-selection escape frequency by ∼40-fold. We fundamentally improved the tolC counter-selection by supplementing a second agent, vancomycin, which reduces counter-selection escape by 425-fold, compared colicin E1 alone. Combining these improvements in a mismatch repair proficient strain reduced counter-selection escape frequency by 1.3E6-fold in total, making tolC counter-selection as effective as most selectable markers, and adding a valuable tool to the genome editing toolbox. These improvements permitted us to perform stable and continuous rounds of selection/counter-selection using tolC, enabling replacement of 10 alleles without requiring genotypic screening for the first time. Finally, we combined these advances to create an optimized E. coli strain for genome engineering that is ∼10-fold more efficient at achieving allelic diversity than previous best practices.
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Affiliation(s)
- Christopher J Gregg
- Department of Genetics and Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA 02115, USA, Program in Chemical Biology, Harvard University, Cambridge, MA 02138, USA, Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA and Molecular, Cellular, Developmental and Systems Biology Institute, Yale University, New Haven, CT 06516, USA
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Abstract
The number of complete genome sequences explodes more and more with each passing year. Thus, methods for genome annotation need to be honed constantly to handle the deluge of information. Annotation of pseudogenes (i.e., gene copies that appear not to make a functional protein) in genomes is a persistent problem; here, we overview pseudogene annotation methods that are based on the detection of sequence homology in genomic DNA.
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Affiliation(s)
- Paul M Harrison
- Department of Biology, McGill University, Stewart Biology Building, 1205 Doctor Penfield Avenue, Montreal, QC, Canada, H3A 1B1,
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45
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Wang H, Bian X, Xia L, Ding X, Müller R, Zhang Y, Fu J, Stewart AF. Improved seamless mutagenesis by recombineering using ccdB for counterselection. Nucleic Acids Res 2013; 42:e37. [PMID: 24369425 PMCID: PMC3950717 DOI: 10.1093/nar/gkt1339] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recombineering, which is the use of homologous recombination for DNA engineering in Escherichia coli, usually uses antibiotic selection to identify the intended recombinant. When combined in a second step with counterselection using a small molecule toxin, seamless products can be obtained. Here, we report the advantages of a genetic strategy using CcdB as the counterselectable agent. Expression of CcdB is toxic to E. coli in the absence of the CcdA antidote so counterselection is initiated by the removal of CcdA expression. CcdB counterselection is robust and does not require titrations or experiment-to-experiment optimization. Because counterselection strategies necessarily differ according to the copy number of the target, we describe two variations. For multi-copy targets, we use two E. coli hosts so that counterselection is exerted by the transformation step that is needed to separate the recombined and unrecombined plasmids. For single copy targets, we put the ccdA gene onto the temperature-sensitive pSC101 Red expression plasmid so that counterselection is exerted by the standard temperature shift to remove the expression plasmid. To reduce unwanted intramolecular recombination, we also combined CcdB counterselection with Redα omission. These options improve the use of counterselection in recombineering with BACs, plasmids and the E. coli chromosome.
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Affiliation(s)
- Hailong Wang
- Hunan Provincial Key Laboratory for Microbial Molecular Biology-State Key Laboratory Breeding Base of Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, People's Republic of China, Department of Genomics, Dresden University of Technology, BioInnovations-Zentrum, Tatzberg 47-51, 01307 Dresden, Germany, Shandong University-Helmholtz Joint Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu 27, 250100 Jinan, People's Republic of China, Helmholtz Institute for Pharmaceutical Research, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, PO Box 151150, 66041 Saarbrücken, Germany and Gene Bridges GmbH, Building C2.3, Saarland University, 66123 Saarbrücken, Germany
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46
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Li XT, Thomason LC, Sawitzke JA, Costantino N, Court DL. Positive and negative selection using the tetA-sacB cassette: recombineering and P1 transduction in Escherichia coli. Nucleic Acids Res 2013; 41:e204. [PMID: 24203710 PMCID: PMC3905872 DOI: 10.1093/nar/gkt1075] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The two-step process of selection and counter-selection is a standard way to enable genetic modification and engineering of bacterial genomes using homologous recombination methods. The tetA and sacB genes are contained in a DNA cassette and confer a novel dual counter-selection system. Expression of tetA confers bacterial resistance to tetracycline (TcR) and also causes sensitivity to the lipophillic chelator fusaric acid; sacB causes sensitivity to sucrose. These two genes are introduced as a joint DNA cassette into Escherichia coli by selection for TcR. A medium containing both fusaric acid and sucrose has been developed, in which, coexpression of tetA-sacB is orders of magnitude more sensitive as a counter-selection agent than either gene alone. In conjunction with the homologous recombination methods of recombineering and P1 transduction, this powerful system has been used to select changes in the bacterial genome that cannot be directly detected by other counter-selection systems.
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Affiliation(s)
- Xin-Tian Li
- Molecular Control and Genetics Section, Gene Regulation and Chromosome Biology, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA and Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702, USA
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47
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Wright O, Stan GB, Ellis T. Building-in biosafety for synthetic biology. Microbiology (Reading) 2013; 159:1221-1235. [DOI: 10.1099/mic.0.066308-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Oliver Wright
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Tom Ellis
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
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48
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Chan WL, Yang WK, Huang HD, Chang JG. pseudoMap: an innovative and comprehensive resource for identification of siRNA-mediated mechanisms in human transcribed pseudogenes. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2013; 2013:bat001. [PMID: 23396300 PMCID: PMC3567485 DOI: 10.1093/database/bat001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RNA interference (RNAi) is a gene silencing process within living cells, which is controlled by the RNA-induced silencing complex with a sequence-specific manner. In flies and mice, the pseudogene transcripts can be processed into short interfering RNAs (siRNAs) that regulate protein-coding genes through the RNAi pathway. Following these findings, we construct an innovative and comprehensive database to elucidate siRNA-mediated mechanism in human transcribed pseudogenes (TPGs). To investigate TPG producing siRNAs that regulate protein-coding genes, we mapped the TPGs to small RNAs (sRNAs) that were supported by publicly deep sequencing data from various sRNA libraries and constructed the TPG-derived siRNA-target interactions. In addition, we also presented that TPGs can act as a target for miRNAs that actually regulate the parental gene. To enable the systematic compilation and updating of these results and additional information, we have developed a database, pseudoMap, capturing various types of information, including sequence data, TPG and cognate annotation, deep sequencing data, RNA-folding structure, gene expression profiles, miRNA annotation and target prediction. As our knowledge, pseudoMap is the first database to demonstrate two mechanisms of human TPGs: encoding siRNAs and decoying miRNAs that target the parental gene. pseudoMap is freely accessible at http://pseudomap.mbc.nctu.edu.tw/. Database URL:http://pseudomap.mbc.nctu.edu.tw/
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Affiliation(s)
- Wen-Ling Chan
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu, Taiwan
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49
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Shyam K Sharan KB, Sharan SK. Manipulating the Mouse Genome Using Recombineering. ADVANCES IN GENETICS 2013; 2. [PMID: 31404315 DOI: 10.4172/2169-0111.1000108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genetically engineered mouse models are indispensable for understanding the biological function of genes, understanding the genetic basis of human diseases and for preclinical testing of novel therapies. Generation of such mouse models has been possible because of our ability to manipulate the mouse genome. Recombineering is a highly efficient recombination-based method of genetic engineering that has revolutionized our ability to generate mouse models. Since recombineering technology is not dependent on the availability of restriction enzyme recognition sites, it allows us to modify the genome with great precision. It requires homology arms as short as 40 bases for recombination, which makes it relatively easy to generate targeting constructs to insert, change or delete either a single nucleotide or a DNA fragment several kb in size; insert selectable markers, reporter genes or add epitope tags to any gene of interest. In this review, we focus on the development of recombineering technology and its application in the generation of transgenic and knockout or knock-in mouse models. High throughput generation of gene targeting vectors, used to construct knockout alleles in mouse embryonic stem cells, is now feasible because of this technology. The challenge now is to use the "designer" mice to develop novel therapies to prevent, cure or effectively manage some the most debilitating human diseases.
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Affiliation(s)
| | - Shyam K Sharan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702
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50
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Gu X, Li C, Cai Y, Dong H, Xu W, Tian H, Yang J. Construction of Lactococcus lactis thyA-null using the Red recombination system. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-012-0548-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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