51
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Pang X, Tong Y, Xue W, Yang YF, Chen X, Liu J, Chen D. Expression and characterization of recombinant human lactoferrin in edible alga Chlamydomonas reinhardtii. Biosci Biotechnol Biochem 2019; 83:851-859. [DOI: 10.1080/09168451.2019.1569498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
ABSTRACT
Lactoferrin (LF) is a naturally occurring iron-binding glycoprotein with a variety of biological functions. It has increasing demand every year and huge market potential. In this study, we explored the feasibility of expressing human LF (hLF) in edible algae C. reinhardtii. A codon-optimized hLF gene was synthesized, inserted into pCAMBIA-1301C and transformed into C. reinhardtii SP strain. In total, 7 hLF-expressing clones were selected with clone 121 exhibiting the highest expression level. The hLF-containing algal extract significantly inhibited the growth of bacteria such as Escherichia coli and Klebsiella variicola. During acute toxicity experiment no acute toxicity was detected, especially on changes of the body weight and histopathology of organs. The recombinant hLF possessed a similar or modestly reduced stability compared to commercial hLF standard. Our data indicated that expression of hLF in C. reinhardtii is feasible and paved a way to commercial production of lactoferrin using edible Chlamydomonas expression system.
Abbreviations: atrazine chlorohydrolase gene (atzA); bovine serum albumin (BSA); human LF (hLF); lactoferrin (LF); Luria-Bertani (LB); quantitative reverse transcriptase PCR (qRT-PCR) ; SDS polyacrylamide gel electrophoresis (SDS-PAGE); Tris-acetate phosphate (TAP); western blotting (WB)
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Affiliation(s)
- Xiaonan Pang
- College of Life Sciences, Nankai University, Tianjin, China
| | - Yuxi Tong
- College of Life Sciences, Nankai University, Tianjin, China
| | - Wenzhi Xue
- College of Life Sciences, Nankai University, Tianjin, China
| | - Yi-feng Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Xiwen Chen
- College of Life Sciences, Nankai University, Tianjin, China
| | - Jia Liu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Defu Chen
- College of Life Sciences, Nankai University, Tianjin, China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
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52
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Armarego-Marriott T, Kowalewska Ł, Burgos A, Fischer A, Thiele W, Erban A, Strand D, Kahlau S, Hertle A, Kopka J, Walther D, Reich Z, Schöttler MA, Bock R. Highly Resolved Systems Biology to Dissect the Etioplast-to-Chloroplast Transition in Tobacco Leaves. PLANT PHYSIOLOGY 2019; 180:654-681. [PMID: 30862726 PMCID: PMC6501100 DOI: 10.1104/pp.18.01432] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/19/2019] [Indexed: 05/17/2023]
Abstract
Upon exposure to light, plant cells quickly acquire photosynthetic competence by converting pale etioplasts into green chloroplasts. This developmental transition involves the de novo biogenesis of the thylakoid system and requires reprogramming of metabolism and gene expression. Etioplast-to-chloroplast differentiation involves massive changes in plastid ultrastructure, but how these changes are connected to specific changes in physiology, metabolism, and expression of the plastid and nuclear genomes is poorly understood. Here, we describe a new experimental system in the dicotyledonous model plant tobacco (Nicotiana tabacum) that allows us to study the leaf deetiolation process at the systems level. We have determined the accumulation kinetics of photosynthetic complexes, pigments, lipids, and soluble metabolites and recorded the dynamic changes in plastid ultrastructure and in the nuclear and plastid transcriptomes. Our data describe the greening process at high temporal resolution, resolve distinct genetic and metabolic phases during deetiolation, and reveal numerous candidate genes that may be involved in light-induced chloroplast development and thylakoid biogenesis.
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Affiliation(s)
| | - Łucja Kowalewska
- Faculty of Biology, Department of Plant Anatomy and Cytology, University of Warsaw, 02-096 Warszawa, Poland
| | - Asdrubal Burgos
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Laboratorio de Biotecnología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, CP 45200 Zapopan, Jalisco, Mexico
| | - Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Alexander Erban
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Deserah Strand
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- targenomix GmbH, 14476 Potsdam, Germany
| | - Alexander Hertle
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Joachim Kopka
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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53
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Das S, Bansal M. Variation of gene expression in plants is influenced by gene architecture and structural properties of promoters. PLoS One 2019; 14:e0212678. [PMID: 30908494 PMCID: PMC6433290 DOI: 10.1371/journal.pone.0212678] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 02/07/2019] [Indexed: 12/03/2022] Open
Abstract
In higher eukaryotes, gene architecture and structural properties of promoters have emerged as significant factors influencing variation in number of transcripts (expression level) and specificity of gene expression in a tissue (expression breadth), which eventually shape the phenotype. In this study, transcriptome data of different tissue types at various developmental stages of A. thaliana, O. sativa, S. bicolor and Z. mays have been used to understand the relationship between properties of gene components and its expression. Our findings indicate that in plants, among all gene architecture and structural properties of promoters, compactness of genes in terms of intron content is significantly linked to gene expression level and breadth, whereas in human an exactly opposite scenario is seen. In plants, for the first time we have carried out a quantitative estimation of effect of a particular trait on expression level and breadth, by using multiple regression analysis and it confirms that intron content of primary transcript (as %) is a powerful determinant of expression breadth. Similarly, further regression analysis revealed that among structural properties of the promoters, stability is negatively linked to expression breadth, while DNase1 sensitivity strongly governs gene expression breadth in monocots and gene expression level in dicots. In addition, promoter regions of tissue specific genes are found to be enriched with TATA box and Y-patch motifs. Finally, multi copy orthologous genes in plants are found to be longer, highly regulated and tissue specific.
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Affiliation(s)
- Sanjukta Das
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Manju Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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54
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Tabatabaei I, Dal Bosco C, Bednarska M, Ruf S, Meurer J, Bock R. A highly efficient sulfadiazine selection system for the generation of transgenic plants and algae. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:638-649. [PMID: 30144344 PMCID: PMC6381783 DOI: 10.1111/pbi.13004] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 08/17/2018] [Indexed: 05/02/2023]
Abstract
The genetic transformation of plant cells is critically dependent on the availability of efficient selectable marker gene. Sulfonamides are herbicides that, by inhibiting the folic acid biosynthetic pathway, suppress the growth of untransformed cells. Sulfonamide resistance genes that were previously developed as selectable markers for plant transformation were based on the assumption that, in plants, the folic acid biosynthetic pathway resides in the chloroplast compartment. Consequently, the Sul resistance protein, a herbicide-insensitive dihydropteroate synthase, was targeted to the chloroplast. Although these vectors produce transgenic plants, the transformation efficiencies are low compared to other markers. Here, we show that this inefficiency is due to the erroneous assumption that the folic acid pathway is located in chloroplasts. When the RbcS transit peptide was replaced by a transit peptide for protein import into mitochondria, the compartment where folic acid biosynthesis takes place in yeast, much higher resistance to sulfonamide and much higher transformation efficiencies are obtained, suggesting that current sul vectors are likely to function due to low-level mistargeting of the resistance protein to mitochondria. We constructed a series of optimized transformation vectors and demonstrate that they produce transgenic events at very high frequency in both the seed plant tobacco and the green alga Chlamydomonas reinhardtii. Co-transformation experiments in tobacco revealed that sul is even superior to nptII, the currently most efficient selectable marker gene, and thus provides an attractive marker for the high-throughput genetic transformation of plants and algae.
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Affiliation(s)
- Iman Tabatabaei
- Max‐Planck‐Institut für Molekulare PflanzenphysiologiePotsdam‐GolmGermany
| | - Cristina Dal Bosco
- Department für Biologie ILudwig‐Maximilians‐Universität MünchenMünchenGermany
- Present address:
Pioneer Hi‐Bred Northern Europe Service Division GmbHEschbachGermany
| | - Marta Bednarska
- Max‐Planck‐Institut für Molekulare PflanzenphysiologiePotsdam‐GolmGermany
| | - Stephanie Ruf
- Max‐Planck‐Institut für Molekulare PflanzenphysiologiePotsdam‐GolmGermany
| | - Jörg Meurer
- Department für Biologie ILudwig‐Maximilians‐Universität MünchenMünchenGermany
| | - Ralph Bock
- Max‐Planck‐Institut für Molekulare PflanzenphysiologiePotsdam‐GolmGermany
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55
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Ruf S, Forner J, Hasse C, Kroop X, Seeger S, Schollbach L, Schadach A, Bock R. High-efficiency generation of fertile transplastomic Arabidopsis plants. NATURE PLANTS 2019; 5:282-289. [PMID: 30778165 PMCID: PMC6420123 DOI: 10.1038/s41477-019-0359-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/07/2019] [Indexed: 05/20/2023]
Abstract
The development of technologies for the stable genetic transformation of plastid (chloroplast) genomes has been a boon to both basic and applied research. However, extension of the transplastomic technology to major crops and model plants has proven extremely challenging, and the species range of plastid transformation is still very much limited in that most species currently remain recalcitrant to plastid genome engineering. Here, we report an efficient plastid transformation technology for the model plant Arabidopsis thaliana that relies on root-derived microcalli as a source tissue for biolistic transformation. The method produces fertile transplastomic plants at high frequency when combined with a clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9)-generated knockout allele of a nuclear locus that enhances sensitivity to the selection agent used for isolation of transplastomic events. Our work makes the model organism of plant biology amenable to routine engineering of the plastid genome, facilitates the combination of plastid engineering with the power of Arabidopsis nuclear genetics, and informs the future development of plastid transformation protocols for other recalcitrant species.
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Affiliation(s)
- Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Joachim Forner
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Claudia Hasse
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Xenia Kroop
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Stefanie Seeger
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Laura Schollbach
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Anne Schadach
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany.
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56
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Yang X, Peng J, Pan J. Nourseothricin N-acetyl transferase (NAT), a new selectable marker for nuclear gene expression in Chlamydomonas. PLANT METHODS 2019; 15:140. [PMID: 31827577 PMCID: PMC6862857 DOI: 10.1186/s13007-019-0526-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/13/2019] [Indexed: 05/16/2023]
Abstract
BACKGROUND Chlamydomonas reinhardtii is a unicellular green alga, which is a most commonly used model organism for basic research and biotechnological applications. Generation of transgenic strains, which usually requires selectable markers, is instrumental in such studies/applications. Compared to other organisms, the number of selectable markers is limited in this organism. Nourseothricin (NTC) N-acetyl transferase (NAT) has been reported as a selectable marker in a variety of organisms but not including C. reinhardtii. Thus, we investigated whether NAT was useful and effective for selection of transgenic strains in C. reinhardtii. The successful use of NAT would provide alterative choice for selectable markers in this organism and likely in other microalgae. RESULTS C. reinhardtii was sensitive to NTC at concentrations as low as 5 µg/ml. There was no cross-resistance to nourseothricin in strains that had been transformed with hygromycin B and/or paromomycin resistance genes. A codon-optimized NAT from Streptomyces noursei was synthesized and assembled into different expression vectors followed by transformation into Chlamydomonas. Around 500 transformants could be obtained by using 50 ng DNA on selection with 10 µg/ml NTC. The transformants exhibited normal growth rate and were stable at least for 10 months on conditions even without selection. We successfully tested that NAT could be used as a selectable marker for ectopic expression of IFT54-HA in strains with paromomycin and hygromycin B resistance markers. We further showed that the selection rate for IFT54-HA positive clones was greatly increased by fusing IFT54-HA to NAT and processing with the FMDV 2A peptide. CONCLUSIONS This work represents the first demonstration of stable expression of NAT in the nuclear genome of C. reinhardtii and provides evidence that NAT can be used as an effective selectable marker for transgenic strains. It provides alterative choice for selectable markers in C. reinhardtii. NAT is compatible with paromomycin and hygromycin B resistance genes, which allows for multiple selections.
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Affiliation(s)
- Xinjia Yang
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Jialin Peng
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Junmin Pan
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000 Shandong China
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57
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Vinyard WA, Fleming AM, Ma J, Burrows CJ. Characterization of G-Quadruplexes in Chlamydomonas reinhardtii and the Effects of Polyamine and Magnesium Cations on Structure and Stability. Biochemistry 2018; 57:6551-6561. [PMID: 30411886 DOI: 10.1021/acs.biochem.8b00749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydomonas reinhardtii is a green alga with a very GC-rich genome (67%) and a high density of potential G-quadruplex-forming sequences (PQSs). Using the Ensembl Plants DNA database, 19 PQSs were selected, and their ability to fold in vitro was examined using four experimental methods. Our results support in vitro folding of 18 of the 19 PQSs selected for study. The high physiological polyamine concentrations in C. reinhardtii create unique conditions for studying G4 folding. We investigated whether high polyamine concentrations affect the stability and structural fold of two polymorphic G4s selected from the cohort of PQSs. The two polymorphic G4s selected were found to be greatly stabilized when studied at the physiologically high polyamine concentrations. Lastly, the effects of physiologically relevant Mg2+ concentrations were tested on both of the polymorphic G4s, and one of the G4s shifted from a dynamic mixture of folds to favor a parallel fold in the presence of Mg2+. Our work supports the concept of folding of G4s under the unique conditions observed in C. reinhardtii, and these structures, being located in promoter regions of DNA repair and photosynthetic genes, might be relevant structures in the physiology of C. reinhardtii.
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Affiliation(s)
- W Andrew Vinyard
- Department of Chemistry , University of Utah , Salt Lake City , Utah 84112-0850 , United States
| | - Aaron M Fleming
- Department of Chemistry , University of Utah , Salt Lake City , Utah 84112-0850 , United States
| | - Jingwei Ma
- Department of Chemistry , University of Utah , Salt Lake City , Utah 84112-0850 , United States
| | - Cynthia J Burrows
- Department of Chemistry , University of Utah , Salt Lake City , Utah 84112-0850 , United States
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58
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Crozet P, Navarro FJ, Willmund F, Mehrshahi P, Bakowski K, Lauersen KJ, Pérez-Pérez ME, Auroy P, Gorchs Rovira A, Sauret-Gueto S, Niemeyer J, Spaniol B, Theis J, Trösch R, Westrich LD, Vavitsas K, Baier T, Hübner W, de Carpentier F, Cassarini M, Danon A, Henri J, Marchand CH, de Mia M, Sarkissian K, Baulcombe DC, Peltier G, Crespo JL, Kruse O, Jensen PE, Schroda M, Smith AG, Lemaire SD. Birth of a Photosynthetic Chassis: A MoClo Toolkit Enabling Synthetic Biology in the Microalga Chlamydomonas reinhardtii. ACS Synth Biol 2018; 7:2074-2086. [PMID: 30165733 DOI: 10.1021/acssynbio.8b00251] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microalgae are regarded as promising organisms to develop innovative concepts based on their photosynthetic capacity that offers more sustainable production than heterotrophic hosts. However, to realize their potential as green cell factories, a major challenge is to make microalgae easier to engineer. A promising approach for rapid and predictable genetic manipulation is to use standardized synthetic biology tools and workflows. To this end we have developed a Modular Cloning toolkit for the green microalga Chlamydomonas reinhardtii. It is based on Golden Gate cloning with standard syntax, and comprises 119 openly distributed genetic parts, most of which have been functionally validated in several strains. It contains promoters, UTRs, terminators, tags, reporters, antibiotic resistance genes, and introns cloned in various positions to allow maximum modularity. The toolkit enables rapid building of engineered cells for both fundamental research and algal biotechnology. This work will make Chlamydomonas the next chassis for sustainable synthetic biology.
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Affiliation(s)
- Pierre Crozet
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | | | - Felix Willmund
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Kamil Bakowski
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kyle J. Lauersen
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Maria-Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Pascaline Auroy
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Aleix Gorchs Rovira
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Susana Sauret-Gueto
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Justus Niemeyer
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Benjamin Spaniol
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Jasmine Theis
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Raphael Trösch
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Lisa-Desiree Westrich
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Baier
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Wolfgang Hübner
- Biomolecular Photonics, Department of Physics, Bielefeld University, Bielefeld, 33615, Germany
| | - Felix de Carpentier
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Mathieu Cassarini
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Antoine Danon
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Julien Henri
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Christophe H. Marchand
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Marcello de Mia
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Kevin Sarkissian
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - David C. Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - José-Luis Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Olaf Kruse
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Poul-Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Schroda
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Stéphane D. Lemaire
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
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Replication of bacterial plasmids in the nucleus of the red alga Porphyridium purpureum. Nat Commun 2018; 9:3451. [PMID: 30150628 PMCID: PMC6110788 DOI: 10.1038/s41467-018-05651-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/19/2018] [Indexed: 11/25/2022] Open
Abstract
Rhodophytes (red algae) are a diverse group of algae with great ecological and economic importance. However, tools for post-genomic research on red algae are still largely lacking. Here, we report the development of an efficient genetic transformation system for the model rhodophyte Porphyridium purpureum. We show that transgenes can be expressed to unprecedented levels of up to 5% of the total soluble protein. Surprisingly, the transgenic DNA is maintained episomally, as extrachromosomal high-copy number plasmid. The bacterial replication origin confers replication in the algal nucleus, thus providing an intriguing example of a prokaryotic replication origin functioning in a eukaryotic system. The extended presence of bacterial episomal elements may provide an evolutionary explanation for the frequent natural occurrence of extrachromosomal plasmids in red algae, and may also have contributed to the high rate of horizontal gene transfer from bacteria to the nuclear genome of Porphyridium purpureum and other rhodophytes. Genetic tools for research on red algae (rhodophytes) are lacking. Here, Li and Bock present an efficient genetic transformation system for a model rhodophyte, and show that the transgenic DNA can be maintained as an extrachromosomal multi-copy plasmid in the algal nucleus.
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60
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Baier T, Wichmann J, Kruse O, Lauersen KJ. Intron-containing algal transgenes mediate efficient recombinant gene expression in the green microalga Chlamydomonas reinhardtii. Nucleic Acids Res 2018; 46:6909-6919. [PMID: 30053227 PMCID: PMC6061784 DOI: 10.1093/nar/gky532] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/16/2018] [Accepted: 06/08/2018] [Indexed: 12/27/2022] Open
Abstract
Among green freshwater microalgae, Chlamydomonas reinhardtii has the most comprehensive and developed molecular toolkit, however, advanced genetic and metabolic engineering driven from the nuclear genome is generally hindered by inherently low transgene expression levels. Progressive strain development and synthetic promoters have improved the capacity of transgene expression; however, the responsible regulatory mechanisms are still not fully understood. Here, we elucidate the sequence specific dynamics of native regulatory element insertion into nuclear transgenes. Systematic insertions of the first intron of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit 2 (rbcS2i1) throughout codon-optimized coding sequences (CDS) generates optimized algal transgenes which express reliably in C. reinhardtii. The optimal rbcS2i1 insertion site for efficient splicing was systematically determined and improved gene expression rates were shown using a codon-optimized sesquiterpene synthase CDS. Sequential insertions of rbcS2i1 were found to have a step-wise additive effect on all levels of transgene expression, which is likely correlated to a synergy of transcriptional machinery recruitment and mimicking the short average exon lengths natively found in the C. reinhardtii genome. We further demonstrate the value of this optimization with five representative transgene examples and provide guidelines for the design of any desired sequence with this strategy.
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MESH Headings
- Abies/enzymology
- Abies/genetics
- Chlamydomonas reinhardtii/genetics
- Codon/genetics
- DNA, Plant/genetics
- DNA, Recombinant/genetics
- Gene Expression Regulation, Plant
- Genes, Plant
- Genes, Synthetic
- Introns
- Isomerases/biosynthesis
- Isomerases/genetics
- Mutagenesis, Insertional
- Plant Proteins/biosynthesis
- Plant Proteins/genetics
- Pogostemon/enzymology
- Pogostemon/genetics
- Protein Engineering
- RNA Splicing
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Recombinant Proteins/biosynthesis
- Ribulose-Bisphosphate Carboxylase/genetics
- Transgenes
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Affiliation(s)
- Thomas Baier
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Julian Wichmann
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Olaf Kruse
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Kyle J Lauersen
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
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Geng S, Miyagi A, Umen JG. Evolutionary divergence of the sex-determining gene MID uncoupled from the transition to anisogamy in volvocine algae. Development 2018; 145:dev.162537. [PMID: 29549112 DOI: 10.1242/dev.162537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/13/2018] [Indexed: 12/28/2022]
Abstract
Volvocine algae constitute a unique comparative model for investigating the evolution of oogamy from isogamous mating types. The sex- or mating type-determining gene MID encodes a conserved RWP-RK transcription factor found in either the MT- or male mating locus of dioecious volvocine species. We previously found that MID from the isogamous species Chlamydomonas reinhardtii (CrMID) could not induce ectopic spermatogenesis when expressed heterologously in Volvox carteri females, suggesting coevolution of Mid function with gamete dimorphism. Here we found that ectopic expression of MID from the anisogamous species Pleodorina starrii (PsMID) could efficiently induce spermatogenesis when expressed in V. carteri females and, unexpectedly, that GpMID from the isogamous species Gonium pectorale was also able to induce V. carteri spermatogenesis. Neither VcMID nor GpMID could complement a C. reinhardtii mid mutant, at least partly owing to instability of heterologous Mid proteins. Our data show that Mid divergence was not a major contributor to the transition between isogamy and anisogamy/oogamy in volvocine algae, and instead implicate changes in cis-regulatory interactions and/or trans-acting factors of the Mid network in the evolution of sexual dimorphism.
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Affiliation(s)
- Sa Geng
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
| | - Ayano Miyagi
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
| | - James G Umen
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
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Lin D, Li L, Xie T, Yin Q, Saksena N, Wu R, Li W, Dai G, Ma J, Zhou X, Chen X. Codon usage variation of Zika virus: The potential roles of NS2B and NS4A in its global pandemic. Virus Res 2018; 247:71-83. [PMID: 29428601 DOI: 10.1016/j.virusres.2018.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/18/2022]
Abstract
A comprehensive demonstration of Zika virus (ZIKV) molecular evolution is essential for understanding its adaptation and expansion in its recent pandemics. Despite several studies on mutations and codon usage in ZIKVs, the variations in codon usage patterns across individual genes and their biological implication remains unclear. Here, we performed a gene-by-gene comparison of the codon usage variation in ZIKVs of the African and Asian lineages. We found that besides the evidence of positive selection (Ka/Ks >1) in the Asian lineage of the ZIKV genome, codon usage patterns were gene-specific and codon usage variation of ZIKV genes, was possibly constrained by their individual functional features, such as transmembrane domains, or antigenicity. In particular, the NS2B and NS4A genes showed distinct codon usage patterns, clearly separating them from the clusters of other genes in the correspondence analysis (CA). In the Asian lineage, the NS2B and NS4A genes showed the highest codon usage bias (ENC values: 51.01 ± 0.72 and 48.89 ± 0.99 respectively), and were subjected to the highest translation selection (ENCobs/ENCexp ratio: 0.847 ± 0.0297 and 0.828 ± 0.0233 respectively) in comparison to the African lineages of ZIKV. The CpG frequency of the NS2B showed a gradual ascending trend in the Asian ZIKV lineages, while in NS4A it was constrained along with the expansion of the Asian lineage. Furthermore, between the African and Asian lineages, differentiated and specific over-represented codons were more prominent in the NS2B and NS4A. Together, our study implies that ZIKVs are in the process of evolutionary fine tuning their codon as seen in the recent pandemics, and NS2B and NS4A could have played a potential role in the molecular evolution of the Asian lineage and their establishment.
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Affiliation(s)
- Dechun Lin
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, Guangdong, China; BGI-Shenzhen, Shenzhen 518083, Guangdong, China; China National Genebank, BGI-Shenzhen, Shenzhen 518083, Guangdong, China.
| | - Liqiang Li
- BGI-Shenzhen, Shenzhen 518083, Guangdong, China; China National Genebank, BGI-Shenzhen, Shenzhen 518083, Guangdong, China.
| | - Tian Xie
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Qingqing Yin
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Nitin Saksena
- BGI-Shenzhen, Shenzhen 518083, Guangdong, China; China National Genebank, BGI-Shenzhen, Shenzhen 518083, Guangdong, China.
| | - Rangke Wu
- The School of Foreign Studies, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Wanyu Li
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Geyang Dai
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Jinmin Ma
- BGI-Shenzhen, Shenzhen 518083, Guangdong, China; China National Genebank, BGI-Shenzhen, Shenzhen 518083, Guangdong, China; Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Xiaohong Zhou
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Xiaoguang Chen
- Department of Pathogen Biology, Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, China.
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Tailored carbon partitioning for phototrophic production of (E)-α-bisabolene from the green microalga Chlamydomonas reinhardtii. Metab Eng 2018; 45:211-222. [DOI: 10.1016/j.ymben.2017.12.010] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 11/27/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022]
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64
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Blaby-Haas CE, Page MD, Merchant SS. Using YFP as a Reporter of Gene Expression in the Green Alga Chlamydomonas reinhardtii. Methods Mol Biol 2018; 1755:135-148. [PMID: 29671268 PMCID: PMC6448394 DOI: 10.1007/978-1-4939-7724-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The unicellular green alga Chlamydomonas reinhardtii is a valuable experimental system in plant biology for studying metal homeostasis. Analyzing transcriptional regulation with promoter-fusion constructs in C. reinhardtii is a powerful method for connecting metal-responsive regulation with cis-regulatory elements, but overcoming expression-level variability between transformants and optimizing experimental conditions can be laborious. Here, we provide detailed protocols for the high-throughput cultivation of C. reinhardtii and assaying Venus fluorescence as a reporter for promoter activity. We also describe procedural considerations for relating metal supply to transcriptional activity.
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Affiliation(s)
| | - M Dudley Page
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA, USA
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65
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Scharff LB, Ehrnthaler M, Janowski M, Childs LH, Hasse C, Gremmels J, Ruf S, Zoschke R, Bock R. Shine-Dalgarno Sequences Play an Essential Role in the Translation of Plastid mRNAs in Tobacco. THE PLANT CELL 2017; 29:3085-3101. [PMID: 29133466 PMCID: PMC5757275 DOI: 10.1105/tpc.17.00524] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/27/2017] [Accepted: 11/08/2017] [Indexed: 05/23/2023]
Abstract
In prokaryotic systems, the translation initiation of many, though not all, mRNAs depends on interaction between a sequence element upstream of the start codon (the Shine-Dalgarno sequence [SD]) and a complementary sequence in the 3' end of the 16S rRNA (anti-Shine-Dalgarno sequence [aSD]). Although many chloroplast mRNAs harbor putative SDs in their 5' untranslated regions and the aSD displays strong conservation, the functional relevance of SD-aSD interactions in plastid translation is unclear. Here, by generating transplastomic tobacco (Nicotiana tabacum) mutants with point mutations in the aSD coupled with genome-wide analysis of translation by ribosome profiling, we provide a global picture of SD-dependent translation in plastids. We observed a pronounced correlation between weakened predicted SD-aSD interactions and reduced translation efficiency. However, multiple lines of evidence suggest that the strength of the SD-aSD interaction is not the only determinant of the translational output of many plastid mRNAs. Finally, the translation efficiency of mRNAs with strong secondary structures around the start codon is more dependent on the SD-aSD interaction than weakly structured mRNAs. Thus, our data reveal the importance of the aSD in plastid translation initiation, uncover chloroplast genes whose translation is influenced by SD-aSD interactions, and provide insights into determinants of translation efficiency in plastids.
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Affiliation(s)
- Lars B Scharff
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Miriam Ehrnthaler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Marcin Janowski
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Liam H Childs
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Claudia Hasse
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Jürgen Gremmels
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
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66
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López-Paz C, Liu D, Geng S, Umen JG. Identification of Chlamydomonas reinhardtii endogenous genic flanking sequences for improved transgene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:1232-1244. [PMID: 28980350 PMCID: PMC5718938 DOI: 10.1111/tpj.13731] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 09/17/2017] [Accepted: 09/22/2017] [Indexed: 05/03/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular green alga that has attracted interest due to its potential biotechnological applications, and as a model for algal biofuel and energy metabolism. Despite all the advantages that this unicellular alga offers, poor and inconsistent expression of nuclear transgenes remains an obstacle for basic and applied research. We used a data-mining strategy to identify highly expressed genes in Chlamydomonas whose flanking sequences were tested for the ability to drive heterologous nuclear transgene expression. Candidates identified in this search included two ribosomal protein genes, RPL35a and RPL23, and ferredoxin, FDX1, whose flanking regions including promoters, terminators and untranslated sequences could drive stable luciferase transgene expression to significantly higher levels than the commonly used Hsp70A-RBCS2 (AR) hybrid promoter/terminator sequences. The RPL23 flanking sequences were further tested using the zeocin resistance gene sh-ble as a reporter in monocistronic and dicistronic constructs, and consistently yielded higher numbers of zeocin-resistant transformants and higher levels of resistance than AR- or PSAD-based vectors. Chlamydomonas RPL23 sequences also enabled transgene expression in Volvox carteri. Our study provides an additional benchmark for strong constitutive expression of transgenes in Chlamydomonas, and develops a general approach for identifying flanking sequences that can be used to drive transgene expression for any organism where transcriptome data are available.
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Affiliation(s)
- Cristina López-Paz
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
| | - Dianyi Liu
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
- Department of Biology, University of Missouri, One University Boulevard, St. Louis, MO 63121, USA
| | - Sa Geng
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
| | - James G. Umen
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA
- Corresponding author: James G. Umen, Donald Danforth Plant Science Center 975 N. Warson Rd., St. Louis, MO 63132, Tel: (314) 587-1689,
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67
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Affiliation(s)
- Xiuren Zhang
- Department of Biochemistry and Biophysics at Texas A&M University, College Station, Texas, USA.
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68
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Sidorenko LV, Lee TF, Woosley A, Moskal WA, Bevan SA, Merlo PAO, Walsh TA, Wang X, Weaver S, Glancy TP, Wang P, Yang X, Sriram S, Meyers BC. GC-rich coding sequences reduce transposon-like, small RNA-mediated transgene silencing. NATURE PLANTS 2017; 3:875-884. [PMID: 29085072 DOI: 10.1038/s41477-017-0040-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 09/29/2017] [Indexed: 05/04/2023]
Abstract
The molecular basis of transgene susceptibility to silencing is poorly characterized in plants; thus, we evaluated several transgene design parameters as means to reduce heritable transgene silencing. Analyses of Arabidopsis plants with transgenes encoding a microalgal polyunsaturated fatty acid (PUFA) synthase revealed that small RNA (sRNA)-mediated silencing, combined with the use of repetitive regulatory elements, led to aggressive transposon-like silencing of canola-biased PUFA synthase transgenes. Diversifying regulatory sequences and using native microalgal coding sequences (CDSs) with higher GC content improved transgene expression and resulted in a remarkable trans-generational stability via reduced accumulation of sRNAs and DNA methylation. Further experiments in maize with transgenes individually expressing three crystal (Cry) proteins from Bacillus thuringiensis (Bt) tested the impact of CDS recoding using different codon bias tables. Transgenes with higher GC content exhibited increased transcript and protein accumulation. These results demonstrate that the sequence composition of transgene CDSs can directly impact silencing, providing design strategies for increasing transgene expression levels and reducing risks of heritable loss of transgene expression.
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Affiliation(s)
| | - Tzuu-Fen Lee
- Delaware Biotechnology Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
- Dupont Pioneer, Johnston, IA, 50131, USA
| | - Aaron Woosley
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - William A Moskal
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Scott A Bevan
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - P Ann Owens Merlo
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Terence A Walsh
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Xiujuan Wang
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Staci Weaver
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Todd P Glancy
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - PoHao Wang
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Xiaozeng Yang
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
- Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, 100097, Beijing, China
| | - Shreedharan Sriram
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Blake C Meyers
- Delaware Biotechnology Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA.
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA.
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69
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Ramos‐Martinez EM, Fimognari L, Sakuragi Y. High-yield secretion of recombinant proteins from the microalga Chlamydomonas reinhardtii. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:1214-1224. [PMID: 28207991 PMCID: PMC5552477 DOI: 10.1111/pbi.12710] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 02/07/2017] [Accepted: 02/12/2017] [Indexed: 05/11/2023]
Abstract
Microalga-based biomanufacturing of recombinant proteins is attracting growing attention due to its advantages in safety, metabolic diversity, scalability and sustainability. Secretion of recombinant proteins can accelerate the use of microalgal platforms by allowing post-translational modifications and easy recovery of products from the culture media. However, currently, the yields of secreted recombinant proteins are low, which hampers the commercial application of this strategy. This study aimed at expanding the genetic tools for enhancing secretion of recombinant proteins in Chlamydomonas reinhardtii, a widely used green microalga as a model organism and a potential industrial biotechnology platform. We demonstrated that the putative signal sequence from C. reinhardtii gametolysin can assist the secretion of the yellow fluorescent protein Venus into the culture media. To increase the secretion yields, Venus was C-terminally fused with synthetic glycomodules comprised of tandem serine (Ser) and proline (Pro) repeats of 10 and 20 units [hereafter (SP)n , wherein n = 10 or 20]. The yields of the (SP)n -fused Venus were higher than Venus without the glycomodule by up to 12-fold, with the maximum yield of 15 mg/L. Moreover, the presence of the glycomodules conferred an enhanced proteolytic protein stability. The Venus-(SP)n proteins were shown to be glycosylated, and a treatment of the cells with brefeldin A led to a suggestion that glycosylation of the (SP)n glycomodules starts in the endoplasmic reticulum (ER). Taken together, the results demonstrate the utility of the gametolysin signal sequence and (SP)n glycomodule to promote a more efficient biomanufacturing of microalgae-based recombinant proteins.
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Affiliation(s)
- Erick Miguel Ramos‐Martinez
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksberg C, CopenhagenDenmark
| | - Lorenzo Fimognari
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksberg C, CopenhagenDenmark
| | - Yumiko Sakuragi
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksberg C, CopenhagenDenmark
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70
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Cheng X, Liu G, Ke W, Zhao L, Lv B, Ma X, Xu N, Xia X, Deng X, Zheng C, Huang K. Building a multipurpose insertional mutant library for forward and reverse genetics in Chlamydomonas. PLANT METHODS 2017; 13:36. [PMID: 28515773 PMCID: PMC5430608 DOI: 10.1186/s13007-017-0183-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 05/02/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND The unicellular green alga, Chlamydomonas reinhardtii, is a classic model for studying flagella and biofuel. However, precise gene editing, such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated protein (Cas9) system, is not widely used in this organism. Screening of random insertional mutant libraries by polymerase chain reaction provides an alternate strategy to obtain null mutants of individual gene. But building, screening, and maintaining such a library was time-consuming and expensive. RESULTS By selecting a suitable parental strain, keeping individual mutants using the agar plate, and designing an insertion cassette-specific primer for library screening, we successfully generated and maintained ~150,000 insertional mutants of Chlamydomonas, which was used for both reverse and forward genetics analysis. We obtained 26 individual mutants corresponding to 20 genes and identified 967 motility-defect mutants including 10 mutants with defective accumulation of intraflagellar transport complex at the basal body. We also obtained 929 mutants defective in oil droplet assembly after nitrogen deprivation. Furthermore, a new insertion cassette with splicing donor sequences at both ends was also constructed, which increased the efficiency of gene interruption. CONCLUSION In summary, this library provides a multifunctional platform both for obtaining mutants of interested genes and for screening of mutants with specific phenotype.
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Affiliation(s)
- Xi Cheng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Gai Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Wenting Ke
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Lijuan Zhao
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Bo Lv
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Xiaocui Ma
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Nannan Xu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Xiaoling Xia
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Xuan Deng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Chunlei Zheng
- College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
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Ponndorf D, Ehmke S, Walliser B, Thoss K, Unger C, Görs S, Daş G, Metges CC, Broer I, Nausch H. Stable production of cyanophycinase in Nicotiana benthamiana and its functionality to hydrolyse cyanophycin in the murine intestine. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:605-613. [PMID: 27808470 PMCID: PMC5399006 DOI: 10.1111/pbi.12658] [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] [Received: 07/08/2016] [Revised: 10/05/2016] [Accepted: 10/30/2016] [Indexed: 05/09/2023]
Abstract
Food supplementation with the conditionally essential amino acid arginine (Arg) has been shown to have nutritional benefits. Degradation of cyanophycin (CGP), a peptide polymer used for nitrogen storage by cyanobacteria, requires cyanophycinase (CGPase) and results in the release of β-aspartic acid (Asp)-Arg dipeptides. The simultaneous production of CGP and CGPase in plants could be a convenient source of Arg dipeptides. Different variants of the cphB coding region from Thermosynechococcus elongatus BP-1 were transiently expressed in Nicotiana benthamiana plants. Translation and enzyme stability were optimized to produce high amounts of active CGPase. Protein stability was increased by the translational fusion of CGPase to the green fluorescent protein (GFP) or to the transit peptide of the small subunit of RuBisCO for peptide production in the chloroplasts. Studies in mice showed that plant-expressed CGP fed in combination with plant-made CGPase was hydrolysed in the intestine, and high levels of ß-Asp-Arg dipeptides were found in plasma, demonstrating dipeptide absorption. However, the lack of an increase in Asp and Arg or its metabolite ornithine in plasma suggests that Arg from CGP was not bioavailable in this mouse group. Intestinal degradation of CGP by CGPase led to low intestinal CGP content 4 h after consumption, but after ingestion of CGP alone, high CGP concentrations remained in the large intestine; this indicated that intact CGP was transported from the small to the large intestine and that CGP was resistant to colonic microbes.
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Affiliation(s)
- Daniel Ponndorf
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
| | - Sven Ehmke
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
- Present address: Paraxel International GmbHKlinikum am Westend, Haus 18, SpandauerDamm 130, 14050BerlinGermany
| | - Benjamin Walliser
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
| | - Kerstin Thoss
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
| | - Christoph Unger
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
| | - Solvig Görs
- Leibniz Institute for Farm Animal Biology (FBN)Institute of Nutritional Physiology ‘Oskar Kellner’DummerstorfGermany
| | - Gürbüz Daş
- Leibniz Institute for Farm Animal Biology (FBN)Institute of Nutritional Physiology ‘Oskar Kellner’DummerstorfGermany
| | - Cornelia C. Metges
- Leibniz Institute for Farm Animal Biology (FBN)Institute of Nutritional Physiology ‘Oskar Kellner’DummerstorfGermany
| | - Inge Broer
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
| | - Henrik Nausch
- Faculty of Agricultural and Environmental SciencesDepartment of Agrobiotechnology and Risk Assessment for Bio‐ and Gene TechnologyUniversity of RostockRostockGermany
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Anderson MS, Muff TJ, Georgianna DR, Mayfield SP. Towards a synthetic nuclear transcription system in green algae: Characterization of Chlamydomonas reinhardtii nuclear transcription factors and identification of targeted promoters. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Nausch H, Broer I. Cyanophycinase CphE from P. alcaligenes produced in different compartments of N. benthamiana degrades high amounts of cyanophycin in plant extracts. Appl Microbiol Biotechnol 2017; 101:2397-2413. [PMID: 27942753 DOI: 10.1007/s00253-016-8020-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/17/2016] [Accepted: 11/21/2016] [Indexed: 12/11/2022]
Abstract
One of the major constraints in pig and poultry farming is the supply of protein-rich forage, containing sufficient amounts of key amino acids such as arginine (Ufaz and Galili 2008). Since these are underrepresented in plant proteins, the usage of plants as feed is limited. The heterologous production of the cyanobacterial storage polymer cyanophycin granule polypeptide (CGP) in plastids increases the amount of arginine substantially (Huhns et al. 2008; Huhns et al. 2009; Nausch et al. 2016a). CGP degradation releases arginine-aspartate dipeptides. CGP is stable in plants because its degradation is exclusively restricted to bacterial cyanophycinases (CGPases; Law et al. 2009). Since animals are also unable to digest CGP, CGPases need to be co-delivered with CGP-containing plant feed in order to release the dipeptides in the gastrointestinal tract of animals during digestion. Therefore, an extracellular CGPase, CphE from Pseudomonas alcaligenes DIP-1, was targeted to the cytosol, ER, and apoplasm of Nicotiana benthamiana. Translocation to the chloroplast was not successful. Although CphE accumulated in high amounts in the cytosol, only moderate levels were present in the ER, while the enzyme was nearly undetectable in the apoplasm. This correlates with the higher instability of post-translationally modified CphE in crude plant extracts. In addition, the production in the ER led to an increased number and size of necroses compared with cytosolic expression and might therefore interfere with the endogenous metabolism in the ER. Due to the high and robust enzyme activity, even moderate CphE concentrations were sufficient to degrade CGP in plant extracts.
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Affiliation(s)
- Henrik Nausch
- Faculty of Agricultural and Environmental Sciences, Department of Agrobiotechnology and Risk Assessment for Bio- und Gene Technology, University of Rostock, Justus-von-Liebig Weg 8, 18059, Rostock, VM, Germany.
| | - Inge Broer
- Faculty of Agricultural and Environmental Sciences, Department of Agrobiotechnology and Risk Assessment for Bio- und Gene Technology, University of Rostock, Justus-von-Liebig Weg 8, 18059, Rostock, VM, Germany
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74
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Wen Y, Zou Z, Li H, Xiang Z, He N. Analysis of codon usage patterns in Morus notabilis based on genome and transcriptome data. Genome 2017; 60:473-484. [PMID: 28177830 DOI: 10.1139/gen-2016-0129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Codons play important roles in regulating gene expression levels and mRNA half-lives. However, codon usage and related studies in multicellular organisms still lag far behind those in unicellular organisms. In this study, we describe for the first time genome-wide patterns of codon bias in Morus notabilis (mulberry tree), and analyze genome-wide codon usage in 12 other species within the order Rosales. The codon usage of M. notabilis was affected by nucleotide composition, mutation pressure, nature selection, and gene expression level. Translational selection optimal codons were identified and highly expressed genes of M. notabilis tended to use the optimal codons. Genes with higher expression levels have shorter coding region and lower amino acid complexity. Housekeeping genes showed stronger translational selection, which, notably, was not caused by the large differences between the expression level of housekeeping genes and other genes.
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Affiliation(s)
- Yan Wen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China.,State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China
| | - Ziliang Zou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China.,State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China
| | - Hongshun Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China.,State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China.,State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China
| | - Ningjia He
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China.,State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road, Beibei, Chongqing 400715, China
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Hiss M, Schneider L, Grosche C, Barth MA, Neu C, Symeonidi A, Ullrich KK, Perroud PF, Schallenberg-Rüdinger M, Rensing SA. Combination of the Endogenous lhcsr1 Promoter and Codon Usage Optimization Boosts Protein Expression in the Moss Physcomitrella patens. FRONTIERS IN PLANT SCIENCE 2017; 8:1842. [PMID: 29163577 PMCID: PMC5671511 DOI: 10.3389/fpls.2017.01842] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 10/10/2017] [Indexed: 05/13/2023]
Abstract
The moss Physcomitrella patens is used both as an evo-devo model and biotechnological production system for metabolites and pharmaceuticals. Strong in vivo expression of genes of interest is important for production of recombinant proteins, e.g., selectable markers, fluorescent proteins, or enzymes. In this regard, the choice of the promoter sequence as well as codon usage optimization are two important inside factors to consider in order to obtain optimum protein accumulation level. To reliably quantify fluorescence, we transfected protoplasts with promoter:GFP fusion constructs and measured fluorescence intensity of living protoplasts in a plate reader system. We used the red fluorescent protein mCherry under 2x 35S promoter control as second reporter to normalize for different transfection efficiencies. We derived a novel endogenous promoter and compared deletion variants with exogenous promoters. We used different codon-adapted green fluorescent protein (GFP) genes to evaluate the influence of promoter choice and codon optimization on protein accumulation in P. patens, and show that the promoter of the gene of P. patens chlorophyll a/b binding protein lhcsr1 drives expression of GFP in protoplasts significantly (more than twofold) better than the commonly used 2x 35S promoter or the rice actin1 promoter. We identified a shortened 677 bp version of the lhcsr1 promoter that retains full activity in protoplasts. The codon optimized GFP yields significantly (more than twofold) stronger fluorescence signals and thus demonstrates that adjusting codon usage in P. patens can increase expression strength. In combination, new promotor and codon optimized GFP conveyed sixfold increased fluorescence signal.
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Affiliation(s)
- Manuel Hiss
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | - Lucas Schneider
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | - Christopher Grosche
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | - Melanie A. Barth
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | - Christina Neu
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | | | - Kristian K. Ullrich
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
| | | | | | - Stefan A. Rensing
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
- BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
- *Correspondence: Stefan A. Rensing,
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76
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Analysis of codon usage patterns in Ginkgo biloba reveals codon usage tendency from A/U-ending to G/C-ending. Sci Rep 2016; 6:35927. [PMID: 27808241 PMCID: PMC5093902 DOI: 10.1038/srep35927] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/07/2016] [Indexed: 11/08/2022] Open
Abstract
As one of the most ancient tree species, the codon usage pattern analysis of Ginkgo biloba is a useful way to understand its evolutionary and genetic mechanisms. Several studies have been conducted on angiosperms, but seldom on gymnosperms. Based on RNA-Seq data of the G. biloba transcriptome, amount to 17,579 unigenes longer than 300 bp were selected and analyzed from 68,547 candidates. The codon usage pattern tended towards more frequently use of A/U-ending codons, which showed an obvious gradient progressing from gymnosperms to dicots to monocots. Meanwhile, analysis of high/low-expression unigenes revealed that high-expression unigenes tended to use G/C-ending codons together with more codon usage bias. Variation of unigenes with different functions suggested that unigenes involving in environment adaptation use G/C-ending codons more frequently with more usage bias, and these results were consistent with the conclusion that the formation of G. biloba codon usage bias was dominated by natural selection.
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77
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Lauersen KJ, Baier T, Wichmann J, Wördenweber R, Mussgnug JH, Hübner W, Huser T, Kruse O. Efficient phototrophic production of a high-value sesquiterpenoid from the eukaryotic microalga Chlamydomonas reinhardtii. Metab Eng 2016; 38:331-343. [DOI: 10.1016/j.ymben.2016.07.013] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/17/2016] [Accepted: 07/26/2016] [Indexed: 02/07/2023]
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Abstract
The genetic, physiological and metabolic diversity of microalgae has driven fundamental research into photosynthesis, flagella structure and function, and eukaryotic evolution. Within the last 10 years these organisms have also been investigated as potential biotechnology platforms, for example to produce high value compounds such as long chain polyunsaturated fatty acids, pigments and antioxidants, and for biodiesel precursors, in particular triacylglycerols (TAGs). Transformation protocols, molecular tools and genome sequences are available for a number of model species including the green alga Chlamydomonas reinhardtii and the diatom Phaeodactylum tricornutum, although for both species there are bottlenecks to be overcome to allow rapid and predictable genetic manipulation. One approach to do this would be to apply the principles of synthetic biology to microalgae, namely the cycle of Design-Build-Test, which requires more robust, predictable and high throughput methods. In this mini-review we highlight recent progress in the areas of improving transgene expression, genome editing, identification and design of standard genetic elements (parts), and the use of microfluidics to increase throughput. We suggest that combining these approaches will provide the means to establish algal synthetic biology, and that application of standard parts and workflows will avoid parallel development and capitalize on lessons learned from other systems.
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Barahimipour R, Neupert J, Bock R. Efficient expression of nuclear transgenes in the green alga Chlamydomonas: synthesis of an HIV antigen and development of a new selectable marker. PLANT MOLECULAR BIOLOGY 2016; 90:403-18. [PMID: 26747175 PMCID: PMC4766212 DOI: 10.1007/s11103-015-0425-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/23/2015] [Indexed: 05/18/2023]
Abstract
The unicellular green alga Chlamydomonas reinhardtii has become an invaluable model system in plant biology. There is also considerable interest in developing this microalga into an efficient production platform for biofuels, pharmaceuticals, green chemicals and industrial enzymes. However, the production of foreign proteins in the nucleocytosolic compartment of Chlamydomonas is greatly hampered by the inefficiency of transgene expression from the nuclear genome. We have recently addressed this limitation by isolating mutant algal strains that permit high-level transgene expression and by determining the contributions of GC content and codon usage to gene expression efficiency. Here we have applied these new tools and explored the potential of Chlamydomonas to produce a recombinant biopharmaceutical, the HIV antigen P24. We show that a codon-optimized P24 gene variant introduced into our algal expression strains give rise to recombinant protein accumulation levels of up to 0.25% of the total cellular protein. Moreover, in combination with an expression strain, a resynthesized nptII gene becomes a highly efficient selectable marker gene that facilitates the selection of transgenic algal clones at high frequency. By establishing simple principles of successful transgene expression, our data open up new possibilities for biotechnological research in Chlamydomonas.
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Affiliation(s)
- Rouhollah Barahimipour
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Juliane Neupert
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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