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Malik T, Klenow L, Karyolaimos A, Gier JWD, Daniels R. Silencing Transcription from an Influenza Reverse Genetics Plasmid in E. coli Enhances Gene Stability. ACS Synth Biol 2023; 12:432-445. [PMID: 36716395 PMCID: PMC9942234 DOI: 10.1021/acssynbio.2c00358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Reverse genetics (RG) systems have been instrumental for determining the molecular aspects of viral replication, pathogenesis, and for the development of therapeutics. Here, we demonstrate that genes encoding the influenza surface antigens hemagglutinin and neuraminidase have varying stability when cloned into a common RG plasmid and transformed into Escherichia coli. Using GFP as a reporter, we demonstrate that E. coli expresses the target genes in the RG plasmid at low levels. Incorporating lac operators or a transcriptional terminator into the plasmid reduced expression and stabilized the viral genes to varying degrees. Sandwiching the viral gene between two lac operators provided the largest contribution to stability and we confirmed the stabilization is Lac repressor-dependent and crucial for subsequent plasmid propagations in E. coli. Viruses rescued from the lac operator-stabilized plasmid displayed similar kinetics and titers to the original plasmid in two different viral backbones. Together, these results indicate that silencing transcription from the plasmid in E. coli helps to maintain the correct influenza gene sequence and that the lac operator addition does not impair virus production. It is envisaged that sandwiching DNA segments between lac operators can be used for reducing DNA segment instability in any plasmid that is propagated in E. coli which express the Lac repressor.
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Affiliation(s)
- Tahir Malik
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Laura Klenow
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Alexandros Karyolaimos
- Department
of Biochemistry and Biophysics, Stockholm
University, 10691 Stockholm, Sweden
| | - Jan-Willem de Gier
- Department
of Biochemistry and Biophysics, Stockholm
University, 10691 Stockholm, Sweden
| | - Robert Daniels
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States,
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Wu Y, You L, Li S, Ma M, Wu M, Ma L, Bock R, Chang L, Zhang J. In vivo Assembly in Escherichia coli of Transformation Vectors for Plastid Genome Engineering. Front Plant Sci 2017; 8:1454. [PMID: 28871270 PMCID: PMC5566966 DOI: 10.3389/fpls.2017.01454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/04/2017] [Indexed: 05/03/2023]
Abstract
Plastid transformation for the expression of recombinant proteins and entire metabolic pathways has become a promising tool for plant biotechnology. However, large-scale application of this technology has been hindered by some technical bottlenecks, including lack of routine transformation protocols for agronomically important crop plants like rice or maize. Currently, there are no standard or commercial plastid transformation vectors available for the scientific community. Construction of a plastid transformation vector usually requires tedious and time-consuming cloning steps. In this study, we describe the adoption of an in vivo Escherichia coli cloning (iVEC) technology to quickly assemble a plastid transformation vector. The method enables simple and seamless build-up of a complete plastid transformation vector from five DNA fragments in a single step. The vector assembled for demonstration purposes contains an enhanced green fluorescent protein (GFP) expression cassette, in which the gfp transgene is driven by the tobacco plastid ribosomal RNA operon promoter fused to the 5' untranslated region (UTR) from gene10 of bacteriophage T7 and the transcript-stabilizing 3'UTR from the E. coli ribosomal RNA operon rrnB. Successful transformation of the tobacco plastid genome was verified by Southern blot analysis and seed assays. High-level expression of the GFP reporter in the transplastomic plants was visualized by confocal microscopy and Coomassie staining, and GFP accumulation was ~9% of the total soluble protein. The iVEC method represents a simple and efficient approach for construction of plastid transformation vector, and offers great potential for the assembly of increasingly complex vectors for synthetic biology applications in plastids.
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Affiliation(s)
- Yuyong Wu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
| | - Lili You
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
| | - Shengchun Li
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
| | - Meiqi Ma
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
| | - Mengting Wu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
| | - Lixin Ma
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
- Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei UniversityWuhan, China
| | - Ralph Bock
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
- Department III, Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam, Germany
| | - Ling Chang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
- Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei UniversityWuhan, China
- *Correspondence: Ling Chang
| | - Jiang Zhang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei UniversityWuhan, China
- Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei UniversityWuhan, China
- Jiang Zhang
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