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Wang W, An X, Yan K, Li Q. Construction and Application of Orthogonal T7 Expression System in Eukaryote: An Overview. Adv Biol (Weinh) 2023; 7:e2200218. [PMID: 36464626 DOI: 10.1002/adbi.202200218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Indexed: 12/12/2022]
Abstract
The T7 system is an orthogonal transcription-system, which is characterized by simplicity, higher efficiency, and higher processivity, and it is used for protein or mRNA synthesis in various biological-systems. In comparison with prokaryotes, the construction of the T7 expression system is still on-going in eukaryotes, but it shows greatly applicable prospects. In the present paper, development of T7 expression system construction in eukaryotes is reviewed, including its construction in animal (mammalian cells, trypanosomatid protozoa, Xenopus oocytes, zebrafish), plant, and microorganism and its application in vaccine production and gene therapy. In addition, the innate challenges of T7 expression system construction in eukaryote and its potential application in vaccine production and gene therapy are discussed.
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Affiliation(s)
- Wenya Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Xiaoyan An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Kun Yan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Qiang Li
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China
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2
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Karki U, Fang H, Guo W, Unnold-Cofre C, Xu J. Cellular engineering of plant cells for improved therapeutic protein production. Plant Cell Rep 2021; 40:1087-1099. [PMID: 33837823 PMCID: PMC8035600 DOI: 10.1007/s00299-021-02693-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/29/2021] [Indexed: 05/07/2023]
Abstract
In vitro cultured plant cells, in particular the tobacco BY-2 cell, have demonstrated their potential to provide a promising bioproduction platform for therapeutic proteins by integrating the merits of whole-plant cultivation systems with those of microbial and mammalian cell cultures. Over the past three decades, substantial progress has been made in improving the plant cell culture system, resulting in a few commercial success cases, such as taliglucerase alfa (Elelyso®), the first FDA-approved recombinant pharmaceutical protein derived from plant cells. However, compared to the major expression hosts (bacteria, yeast, and mammalian cells), plant cells are still largely underutilized, mainly due to low productivity and non-human glycosylation. Modern molecular biology tools, in particular RNAi and the latest genome editing technology CRISPR/Cas9, have been used to modulate the genome of plant cells to create new cell lines that exhibit desired "traits" for producing therapeutic proteins. This review highlights the recent advances in cellular engineering of plant cells towards improved recombinant protein production, including creating cell lines with deficient protease levels or humanized glycosylation, and considers potential development in the future.
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Affiliation(s)
- Uddhab Karki
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR, 72401, USA
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, 72401, USA
| | - Hong Fang
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR, 72401, USA
- College of Agriculture, Arkansas State University, Jonesboro, AR, 72401, USA
| | - Wenzheng Guo
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR, 72401, USA
| | - Carmela Unnold-Cofre
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, 72401, USA
| | - Jianfeng Xu
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR, 72401, USA.
- College of Agriculture, Arkansas State University, Jonesboro, AR, 72401, USA.
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Koczka K, Ernst W, Palmberger D, Klausberger M, Nika L, Grabherr R. Development of a Dual-Vector System Utilizing MicroRNA Mimics of the Autographa californica miR-1 for an Inducible Knockdown in Insect Cells. Int J Mol Sci 2019; 20:E533. [PMID: 30691228 PMCID: PMC6387257 DOI: 10.3390/ijms20030533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 11/16/2022] Open
Abstract
The baculovirus-insect cell expression system is a popular tool for the manufacturing of various attractive recombinant products. Over the years, several attempts have been made to engineer and further improve this production platform by targeting host or baculoviral genes by RNA interference. In this study, an inducible knockdown system was established in insect (Sf9) cells by combining an artificial microRNA precursor mimic of baculoviral origin and the bacteriophage T7 transcription machinery. Four structurally different artificial precursor constructs were created and tested in a screening assay. The most efficient artificial microRNA construct resulted in a 69% reduction in the fluorescence intensity of the target enhanced yellow fluorescent protein (eYFP). Next, recombinant baculoviruses were created carrying either the selected artificial precursor mimic under the transcriptional control of the T7 promoter or solely the T7 RNA polymerase under a baculoviral promoter. Upon co-infecting Sf9 cells with these two viruses, the fluorescence intensity of eYFP was suppressed by ~30⁻40% on the protein level. The reduction in the target mRNA level was demonstrated with real-time quantitative PCR. The presented inducible knockdown system may serve as an important and valuable tool for basic baculovirus-insect cell research and for the improvement of production processes using this platform.
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Affiliation(s)
- Krisztina Koczka
- Austrian Centre of Industrial Biotechnology - acib, A-1190 Vienna, Austria.
- Department of Biotechnology, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
| | - Wolfgang Ernst
- Austrian Centre of Industrial Biotechnology - acib, A-1190 Vienna, Austria.
- Department of Biotechnology, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
| | - Dieter Palmberger
- Austrian Centre of Industrial Biotechnology - acib, A-1190 Vienna, Austria.
| | - Miriam Klausberger
- Austrian Centre of Industrial Biotechnology - acib, A-1190 Vienna, Austria.
- Department of Biotechnology, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
| | - Lisa Nika
- Department of Biotechnology, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
| | - Reingard Grabherr
- Austrian Centre of Industrial Biotechnology - acib, A-1190 Vienna, Austria.
- Department of Biotechnology, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
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Abstract
Bacteriophage T7 promoter and RNA polymerase (T7-Pol) are widely used for recombinant protein expression in bacteria. In plants, there exists conflicting results regarding the efficacy of protein expression from T7-Pol-derived mRNAs. To reconcile these contradictory observations, the expression of green fluorescent protein (GFP) from T7 constructs was evaluated in tobacco protoplasts. T7 constructs transcribed by a nuclearly targeted T7-Pol did not express GFP in plant protoplasts, however T7-Pol lacking a nuclear targeting signal was able to translate cytosolically transcribed mRNAs, but only if the messages contained a viral translation enhancer. GFP expression was further evaluated at the plant level by using agroinfiltration-mediated transient expression system. Unlike for cytosolic expression, nuclear T7 transcripts containing a viral translation enhancer element did not express GFP, and modifications designed to stabilize and facilitate export of T7 transcripts to the cytosol did not improve the expression. We conclude that expression of nuclear T7 constructs is not feasible in tobacco cells, but cytosolic transcription provides an alternative means to over-express RNAs directly in the cytosol.
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Affiliation(s)
- Hyukho Sheen
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
| | - K Andrew White
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
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5
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Abstract
Twenty years ago, breakthroughs for reverse genetics analyses of negative-strand RNA (NSR) viruses were achieved by devising conditions for generation of infectious viruses in susceptible cells. Recombinant strategies have subsequently been engineered for members of all vertebrate NSR virus families, and research arising from these advances has profoundly increased understanding of infection cycles, pathogenesis, and complexities of host interactions of animal NSR viruses. These strategies also permitted development of many applications, including attenuated vaccines and delivery vehicles for therapeutic and biotechnology proteins. However, for a variety of reasons, it was difficult to devise procedures for reverse genetics analyses of plant NSR viruses. In this review, we discuss advances that have circumvented these problems and resulted in construction of a recombinant system for Sonchus yellow net nucleorhabdovirus. We also discuss possible extensions to other plant NSR viruses as well as the applications that may emanate from recombinant analyses of these pathogens.
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Affiliation(s)
- Andrew O Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720;
| | - Zhenghe Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058 China;
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Shih PM, Liang Y, Loqué D. Biotechnology and synthetic biology approaches for metabolic engineering of bioenergy crops. Plant J 2016; 87:103-17. [PMID: 27030440 DOI: 10.1111/tpj.13176] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 05/26/2023]
Abstract
The Green Revolution has fuelled an exponential growth in human population since the mid-20th century. Due to population growth, food and energy demands will soon surpass supply capabilities. To overcome these impending problems, significant improvements in genetic engineering will be needed to complement breeding efforts in order to accelerate the improvement of agronomical traits. The new field of plant synthetic biology has emerged in recent years and is expected to support rapid, precise, and robust engineering of plants. In this review, we present recent advances made in the field of plant synthetic biology, specifically in genome editing, transgene expression regulation, and bioenergy crop engineering, with a focus on traits related to lignocellulose, oil, and soluble sugars. Ultimately, progress and innovation in these fields may facilitate the development of beneficial traits in crop plants to meet society's bioenergy needs.
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Affiliation(s)
- Patrick M Shih
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4th Floor, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Yan Liang
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4th Floor, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Dominique Loqué
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4th Floor, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Université Lyon 1, INSA de Lyon, CNRS, UMR5240, Microbiologie, Adaptation et Pathogénie, 10 rue Raphaël Dubois, F-69622, Villeurbanne, France
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7
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Kim HJ, Lim JW, Jeong H, Lee SJ, Lee DW, Kim T, Lee SJ. Development of a highly specific and sensitive cadmium and lead microbial biosensor using synthetic CadC-T7 genetic circuitry. Biosens Bioelectron 2016; 79:701-8. [DOI: 10.1016/j.bios.2015.12.101] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 12/08/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
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Chou C, Young DD, Deiters A. Photocaged t7 RNA polymerase for the light activation of transcription and gene function in pro- and eukaryotic cells. Chembiochem 2010; 11:972-7. [PMID: 20301166 DOI: 10.1002/cbic.201000041] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A light-activatable bacteriophage T7 RNA polymerase (T7RNAP) has been generated through the site-specific introduction of a photocaged tyrosine residue at the crucial position Tyr639 within the active site of the enzyme. The photocaged tyrosine disrupts polymerase activity by blocking the incoming nucleotide from reaching the active site of the enzyme. However, a brief irradiation with nonphototoxic UV light of 365 nm removes the ortho-nitrobenzyl caging group from Tyr639 and restores the RNA polymerase activity of T7RNAP. The complete orthogonality of T7RNAP to all endogenous RNA polymerases in pro- and eukaryotic systems allowed for the photochemical activation of gene expression in bacterial and mammalian cells. Specifically, E. coli cells were engineered to produce photocaged T7RNAP in the presence of a GFP reporter gene under the control of a T7 promoter. UV irradiation of these cells led to the spatiotemporal activation of GFP expression. In an analogous fashion, caged T7RNAP was transfected into human embryonic kidney (HEK293T) cells. Irradiation with UV light led to the activation of T7RNAP, thereby inducing RNA polymerization and expression of a luciferase reporter gene in tissue culture. The ability to achieve spatiotemporal regulation of orthogonal RNA synthesis enables the precise dissection and manipulation of a wide range of cellular events, including gene function.
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Affiliation(s)
- Chungjung Chou
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
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Lim HS, Vaira AM, Domier LL, Lee SC, Kim HG, Hammond J. Efficiency of VIGS and gene expression in a novel bipartite potexvirus vector delivery system as a function of strength of TGB1 silencing suppression. Virology 2010; 402:149-63. [PMID: 20381827 DOI: 10.1016/j.virol.2010.03.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 02/07/2010] [Accepted: 03/14/2010] [Indexed: 11/27/2022]
Abstract
We have developed plant virus-based vectors for virus-induced gene silencing (VIGS) and protein expression, based on Alternanthera mosaic virus (AltMV), for infection of a wide range of host plants including Nicotiana benthamiana and Arabidopsis thaliana by either mechanical inoculation of in vitro transcripts or via agroinfiltration. In vivo transcripts produced by co-agroinfiltration of bacteriophage T7 RNA polymerase resulted in T7-driven AltMV infection from a binary vector in the absence of the Cauliflower mosaic virus 35S promoter. An artificial bipartite viral vector delivery system was created by separating the AltMV RNA-dependent RNA polymerase and Triple Gene Block (TGB)123-Coat protein (CP) coding regions into two constructs each bearing the AltMV 5' and 3' non-coding regions, which recombined in planta to generate a full-length AltMV genome. Substitution of TGB1 L(88)P, and equivalent changes in other potexvirus TGB1 proteins, affected RNA silencing suppression efficacy and suitability of the vectors from protein expression to VIGS.
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Affiliation(s)
- Hyoun-Sub Lim
- USDA-ARS, Plant Sciences Institute, Molecular Plant Pathology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
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Jamal A, Ko K, Kim HS, Choo YK, Joung H, Ko K. Role of genetic factors and environmental conditions in recombinant protein production for molecular farming. Biotechnol Adv 2009; 27:914-923. [PMID: 19698776 DOI: 10.1016/j.biotechadv.2009.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 07/19/2009] [Accepted: 07/21/2009] [Indexed: 01/03/2023]
Abstract
Plants are generally considered to represent a promising heterologous expression system for the production of valuable recombinant proteins. Minimal upstream plant production cost is a salient feature driving the development of plant expression systems used for the synthesis of recombinant proteins. For such a plant expression system to be fully effective, it is first essential to improve plant productivity by plant biomass after inserting genes of interest into a suitable plant. Plant productivity is related closely to its growth and development, both of which are affected directly by environmental factors. These environmental factors that affect the cultivation conditions mainly include temperature, light, salinity, drought, nutrition, insects and pests. In addition, genetic factors that affect gene expression at the transcriptional, translational, and post-translational levels are considered to be important factors related to gene expression in plants. Thus, these factors influence both the quality and quantity of recombinant protein produced in transgenic plants. Among the genetic factors, the post-translational process is of particular interest as it influences subcellular localization, protein glycosylation, assembly and folding of therapeutic proteins, consequently affecting both protein quantity and biological quality. In this review, we discuss the effects of cultivation condition and genetic factors on recombinant protein production in transgenic plants.
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Affiliation(s)
- Arshad Jamal
- School of Food Science/Technology, College of Natural Resources, Yeungnam University, Gyeonbuk 712-749, Republic of Korea
| | - Kinarm Ko
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Hyun-Soon Kim
- Plant Genomics Research Center, KRIBB, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Young-Kug Choo
- Department of Biological Science, College of Natural Sciences, Institute of Biotechnology Wonkwang University, Iksan, Chonbuk 570-749, Republic of Korea
| | - Hyouk Joung
- Plant Genomics Research Center, KRIBB, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Kisung Ko
- Department of Biological Science, College of Natural Sciences, Institute of Biotechnology Wonkwang University, Iksan, Chonbuk 570-749, Republic of Korea.
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Sharma AK, Sharma MK. Plants as bioreactors: Recent developments and emerging opportunities. Biotechnol Adv 2009; 27:811-832. [PMID: 19576278 PMCID: PMC7125752 DOI: 10.1016/j.biotechadv.2009.06.004] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 06/15/2009] [Accepted: 06/16/2009] [Indexed: 12/18/2022]
Abstract
In recent years, the use of plants as bioreactors has emerged as an exciting area of research and significant advances have created new opportunities. The driving forces behind the rapid growth of plant bioreactors include low production cost, product safety and easy scale up. As the yield and concentration of a product is crucial for commercial viability, several strategies have been developed to boost up protein expression in transgenic plants. Augmenting tissue-specific transcription, elevating transcript stability, tissue-specific targeting, translation optimization and sub-cellular accumulation are some of the strategies employed. Various kinds of products that are currently being produced in plants include vaccine antigens, medical diagnostics proteins, industrial and pharmaceutical proteins, nutritional supplements like minerals, vitamins, carbohydrates and biopolymers. A large number of plant-derived recombinant proteins have reached advanced clinical trials. A few of these products have already been introduced in the market.
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Affiliation(s)
- Arun K Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India.
| | - Manoj K Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
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Jia H, Van Loock B, Liao M, Verbelen JP, Vissenberg K. Combination of the ALCR/alcA ethanol switch and GAL4/VP16-UAS enhancer trap system enables spatial and temporal control of transgene expression in Arabidopsis. Plant Biotechnol J 2007; 5:477-82. [PMID: 17442066 DOI: 10.1111/j.1467-7652.2007.00255.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The experimental control of gene expression in specific tissues or cells at defined time points is a useful tool for the analysis of gene function. GAL4/VP16-UAS enhancer trap lines can be used to selectively express genes in specific tissues or cells, and an ethanol-inducible system can help to control the time of expression. In this study, the combination of the two methods allowed the successful regulation of gene expression in both time and space. For this purpose, a binary vector, 962-UAS::GUS, was constructed in which the ALCR activator and beta-glucuronidase (GUS) reporter gene were placed under the control of upstream activator sequence (UAS) elements and the alcA response element, respectively. Three different GAL4/VP16-UAS enhancer trap lines of Arabidopsis were transformed, resulting in transgenic plants in which GUS activity was detected only on ethanol induction and exclusively in the predicted tissues of the enhancer trap lines. As a library of different enhancer trap lines with distinct green fluorescent protein (GFP) patterns exist, transformation with a similar vector, in which GUS is replaced by another gene, would enable the control of the time and place of transgene expression. We have constructed two vectors for easy cloning of the gene of interest, one with a polylinker site and one that is compatible with the GATEWAY vector conversion system. The method can be extended to other species when enhancer trap lines become available.
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Affiliation(s)
- Hongge Jia
- University of Antwerp, Department of Biology, Plant Physiology and Morphology, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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Liang R, Liu X, Liu J, Ren Q, Liang P, Lin Z, Xie X. A T7-expression system under temperature control could create temperature-sensitive phenotype of target gene in Escherichia coli. J Microbiol Methods 2007; 68:497-506. [PMID: 17169451 DOI: 10.1016/j.mimet.2006.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/16/2006] [Accepted: 10/19/2006] [Indexed: 11/20/2022]
Abstract
Temperature-sensitive (TS) mutants of a gene are ones of which the activity or phenotype is very similar to that of wild type only at certain temperature and they provide extremely powerful tool for studying protein function in vivo. Here we report a novel strategy to generate TS phenotype of the interest gene in Escherichia coli based on a temperature-sensitive T7-expression system. A TS T7-RNA polymerase is generated by interrupting it with a TS intein from Saccharomyces cerevisiae vacuolar ATPase subunit (VMA), resulting that the gene flanked by T7-promoter and T7-terminator will be transcribed only at the permissive temperature (18 degrees C), not at the restrictive temperature (37 degrees C). The feasibility to create TS phenotype of this strategy was detected using lacZ as target. Reverse transcriptase polymerase chain reaction (PCR) indicated that at 18 degrees C, transcripts of T7-promoter controlled lacZ were at least 85 times more than those at 37 degrees C. Western blot analysis and enzymatic assay showed that large amounts of active His6-tagged LacZ produced at 18 degrees C but little at 37 degrees C. This strategy appears more promising than other TS creation methods because the target is pre-designed, no modification is introduced, and only simple DNA manipulation is required.
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Affiliation(s)
- Rubing Liang
- College of Life Science and Technology, Shanghai Jiaotong University, 800 Dong-Chuan Road, Shanghai 200240, China
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14
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Abstract
Several vector systems are available for tissue-specific transactivation or chemical induction of transgene expression in plants. The choice facing researchers is which promoter system to commit to as this determines the range and characteristics of the expression resources available. The decision will not be the same for all species or applications. We present some general discussion on the use of these technologies and review in detail the properties in various (mainly angiosperm) species of the most promising: mGal4:VP16/UAS and pOp/LhG4 for transactivation, and the alc-switch, GVE/VGE, GVG, pOp6/LhGR, and XVE systems for chemical induction.
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Affiliation(s)
- Ian Moore
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
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15
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Abstract
Rice biotechnology has made rapid advances since the first transgenic rice plants were produced 15 years ago. Over the past decade, this progress has resulted in the development of high frequency, routine and reproducible genetic transformation protocols for rice. This technology has been applied to produce rice plants that withstand several abiotic stresses, as well as to gain tolerance against various pests and diseases. In addition, quality improving and increased nutritional value traits have also been introduced into rice. Most of these gains were not possible through conventional breeding technologies. Transgenic rice system has been used to understand the process of transformation itself, the integration pattern of transgene as well as to modulate gene expression. Field trials of transgenic rice, especially insect-resistant rice, have recently been performed and several other studies that are prerequisite for safe release of transgenic crops have been initiated. New molecular improvisations such as inducible expression of transgene and selectable marker-free technology will help in producing superior transgenic product. It is also a step towards alleviating public concerns relating to issues of transgenic technology and to gain regulatory approval. Knowledge gained from rice can also be applied to improve other cereals. The completion of the rice genome sequencing together with a rich collection of full-length cDNA resources has opened up a plethora of opportunities, paving the way to integrate data from the large-scale projects to solve specific biological problems.
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Affiliation(s)
- Shavindra Bajaj
- Gene Technology, The Horticulture and Food Research Institute of New Zealand Limited (HortResearch) 120 Mt. Albert Road, Private Bag 92169, Auckland, New Zealand.
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