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Melis A, Hidalgo Martinez DA, Betterle N. Perspectives of cyanobacterial cell factories. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01056-4. [PMID: 37966575 DOI: 10.1007/s11120-023-01056-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023]
Abstract
Cyanobacteria are prokaryotic photosynthetic microorganisms that can generate, in addition to biomass, useful chemicals and proteins/enzymes, essentially from sunlight, carbon dioxide, and water. Selected aspects of cyanobacterial production (isoprenoids and high-value proteins) and scale-up methods suitable for product generation and downstream processing are addressed in this review. The work focuses on the challenge and promise of specialty chemicals and proteins production, with isoprenoid products and biopharma proteins as study cases, and the challenges encountered in the expression of recombinant proteins/enzymes, which underline the essence of synthetic biology with these microorganisms. Progress and the current state-of-the-art in these targeted topics are emphasized.
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Affiliation(s)
- Anastasios Melis
- Department of Plant and Microbial Biology, University of California, MC-3102, Berkeley, CA, 94720-3102, USA.
| | - Diego Alberto Hidalgo Martinez
- Department of Biology, Healthcare and the Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain
| | - Nico Betterle
- SoLELab, Department of Biotechnology, University of Verona, 37134, Verona, Italy
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Jackson HO, Taunt HN, Mordaka PM, Kumari S, Smith AG, Purton S. CpPosNeg: A positive-negative selection strategy allowing multiple cycles of marker-free engineering of the Chlamydomonas plastome. Biotechnol J 2022; 17:e2200088. [PMID: 35509114 DOI: 10.1002/biot.202200088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/19/2022] [Accepted: 04/23/2022] [Indexed: 02/02/2023]
Abstract
The chloroplast represents an attractive compartment for light-driven biosynthesis of recombinant products, and advanced synthetic biology tools are available for engineering the chloroplast genome ( = plastome) of several algal and plant species. However, producing commercial lines will likely require several plastome manipulations. This presents issues with respect to selectable markers, since there are a limited number available, they can be used only once in a serial engineering strategy, and it is undesirable to retain marker genes for antibiotic resistance in the final transplastome. To address these problems, we have designed a rapid iterative selection system, known as CpPosNeg, for the green microalga Chlamydomonas reinhardtii that allows creation of marker-free transformants starting from wild-type strains. The system employs a dual marker encoding a fusion protein of E. coli aminoglycoside adenyltransferase (AadA: conferring spectinomycin resistance) and a variant of E. coli cytosine deaminase (CodA: conferring sensitivity to 5-fluorocytosine). Initial selection on spectinomycin allows stable transformants to be established and driven to homoplasmy. Subsequent selection on 5-fluorocytosine results in rapid loss of the dual marker through intramolecular recombination between the 3'UTR of the marker and the 3'UTR of the introduced transgene. We demonstrate the versatility of the CpPosNeg system by serial introduction of reporter genes into the plastome.
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Affiliation(s)
- Harry O Jackson
- Department of Structural and Molecular Biology, University College London, London, UK
| | - Henry N Taunt
- Department of Structural and Molecular Biology, University College London, London, UK
| | - Paweł M Mordaka
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Sujata Kumari
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London, UK
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Overcoming Poor Transgene Expression in the Wild-Type Chlamydomonas Chloroplast: Creation of Highly Mosquitocidal Strains of Chlamydomonas reinhardtii. Microorganisms 2022; 10:microorganisms10061087. [PMID: 35744605 PMCID: PMC9229432 DOI: 10.3390/microorganisms10061087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 12/10/2022] Open
Abstract
High-level expression of transgenes in the chloroplast of wild-type Chlamydomonas reinhardtii (C. reinhardtii) remains challenging for many genes (e.g., the cry toxin genes from Bacillus thuringiensis israelensis). The bottleneck is presumed to be post-transcriptional and mediated by the 5′ element and the coding region. Using 5′ elements from highly expressed photosynthesis genes such as atpA did not improve the outcome with cry11A regardless of the promoter. However, when we employed the 5′ UTR from mature rps4 mRNA with clean fusions to promoters, production of the rCry11A protein became largely promoter-dependent. The best results were obtained with the native 16S rrn promoter (−91 to −1). When it was fused to the mature 5′ rps4 UTR, rCry11A protein levels were ~50% higher than was obtained with the inducible system, or ~0.6% of total protein. This level was sufficient to visualize the 73-kDa rCry11A protein on Coomassie-stained gels of total algal protein. In addition, analysis of the expression of these transgenes by RT-PCR indicated that RNA levels roughly correlated with protein production. Live cell bioassays using the best strains as food for 3rd instar Aedes aegypti larvae showed that most larvae were killed even when the cell concentration was as low as 2 × 104 cells/mL. Finally, the results indicate that these highly toxic strains are also quite stable, and thus represent a key milestone in using C. reinhardtii for mosquito control.
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Carro MDLM, Gonorazky G, Soto D, Mamone L, Bagnato C, Pagnussat LA, Beligni MV. Expression of Chlamydomonas reinhardtii chloroplast diacylglycerol acyltransferase 3 is induced by light in concert with triacylglycerol accumulation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:262-276. [PMID: 35043497 DOI: 10.1111/tpj.15671] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 12/15/2021] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
Considerable progress has been made towards the understanding of triacylglycerol (TAG) accumulation in algae. One key aspect is finding conditions that trigger TAG production without reducing cell division. Previously, we identified a soluble diacylglycerol acyltransferase (DGAT), related to plant DGAT3, with heterologous DGAT activity. In this work, we demonstrate that Chlamydomonas reinhardtii DGAT3 localizes to the chloroplast and that its expression is induced by light, in correspondence with TAG accumulation. Dgat3 mRNAs and TAGs increase in both wild-type and starch-deficient cells grown with acetate upon transferring them from dark or low light to higher light levels, albeit affected by the particularities of each strain. The response of dgat3 mRNAs and TAGs to light depends on the pre-existing levels of TAGs, suggesting the existence of a negative regulatory loop in the synthesis pathway, although an effect of TAG turnover cannot be ruled out. Altogether, these results hint towards a possible role of DGAT3 in light-dependent TAG accumulation in C. reinhardtii.
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Affiliation(s)
- María de Las Mercedes Carro
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, B7608FBY, Mar del Plata, Argentina
| | - Gabriela Gonorazky
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, B7608FBY, Mar del Plata, Argentina
| | - Débora Soto
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, B7608FBY, Mar del Plata, Argentina
| | - Leandro Mamone
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, B7608FBY, Mar del Plata, Argentina
| | - Carolina Bagnato
- Instituto de Energía y Desarrollo Sustentable (IEDS), Comisión Nacional de Energía Atómica, Centro Atómico Bariloche, 8400, San Carlos de Bariloche, Argentina
| | - Luciana A Pagnussat
- Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, B7620EMA, Balcarce, Argentina
| | - María Verónica Beligni
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, B7608FBY, Mar del Plata, Argentina
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Harnessing the Algal Chloroplast for Heterologous Protein Production. Microorganisms 2022; 10:microorganisms10040743. [PMID: 35456794 PMCID: PMC9025058 DOI: 10.3390/microorganisms10040743] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
Photosynthetic microbes are gaining increasing attention as heterologous hosts for the light-driven, low-cost production of high-value recombinant proteins. Recent advances in the manipulation of unicellular algal genomes offer the opportunity to establish engineered strains as safe and viable alternatives to conventional heterotrophic expression systems, including for their use in the feed, food, and biopharmaceutical industries. Due to the relatively small size of their genomes, algal chloroplasts are excellent targets for synthetic biology approaches, and are convenient subcellular sites for the compartmentalized accumulation and storage of products. Different classes of recombinant proteins, including enzymes and peptides with therapeutical applications, have been successfully expressed in the plastid of the model organism Chlamydomonas reinhardtii, and of a few other species, highlighting the emerging potential of transplastomic algal biotechnology. In this review, we provide a unified view on the state-of-the-art tools that are available to introduce protein-encoding transgenes in microalgal plastids, and discuss the main (bio)technological bottlenecks that still need to be addressed to develop robust and sustainable green cell biofactories.
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Hidalgo Martinez D, Betterle N, Melis A. Phycocyanin Fusion Constructs for Heterologous Protein Expression Accumulate as Functional Heterohexameric Complexes in Cyanobacteria. ACS Synth Biol 2022; 11:1152-1166. [PMID: 35257571 DOI: 10.1021/acssynbio.1c00449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Overexpression of heterologous proteins from plants, bacteria, and human as fusion constructs in cyanobacteria has been documented in the literature. Typically, the heterologous protein "P" of interest is expressed as a fusion with the abundant CpcB β-subunit of phycocyanin (PC), which was placed in the leader sequence position. The working hypothesis for such overexpressions is that CpcB*P fusion proteins somehow accumulate in a soluble and stable form in the cytosol of the cyanobacteria, retaining the activity of the trailing heterologous "P" protein of interest. The present work revealed a substantially different and previously unobvious picture, comprising the following properties of the above-mentioned CpcB*P fusion constructs: (i) the CpcB*P proteins assemble as functional (α,β*P)3CpcG heterohexameric discs, where α is the CpcA α-subunit of PC, β*P is the CpcB*P fusion protein, the asterisk denotes fusion, and CpcG is the 28.9 kDa PC disc linker polypeptide CpcG1. (ii) The (α,β*P)3CpcG1 complexes covalently bind one open tetrapyrrole bilin co-factor per α-subunit and two bilins per β-subunit. (iii) The (α,β*P)3CpcG1 heterohexameric discs are functionally attached to the Synechocystis allophycocyanin (AP) core cylinders and efficiently transfer excitation energy from the assembled (α,β*P)3CpcG1 heterohexamer to the PSII reaction center, enhancing the rate of photochemical charge separation and electron transfer activity in this photosystem. (iv) In addition to the human interferon α-2 and tetanus toxin fragment C tested in this work, we have shown that enzymes such as the plant-origin isoprene synthase, β-phellandrene synthase, geranyl diphosphate synthase, and geranyl linalool synthase are also overexpressed, while retaining their catalytic activity in the respective fusion construct configuration. (v) Folding models for the (α,β*P)3CpcG1 heterohexameric discs showed the recombinant proteins P to be radially oriented with respect to the (α,β)3 compact disc. Elucidation of the fusion construct configuration and function will pave the way for the rational design of fusion constructs harboring and overexpressing multiple proteins of scientific and commercial interest.
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Affiliation(s)
- Diego Hidalgo Martinez
- Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Nico Betterle
- Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Anastasios Melis
- Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
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Zhang X, Betterle N, Hidalgo Martinez D, Melis A. Recombinant Protein Stability in Cyanobacteria. ACS Synth Biol 2021; 10:810-825. [PMID: 33684287 DOI: 10.1021/acssynbio.0c00610] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The living cell possesses extraordinary molecular and biochemical mechanisms by which to recognize and efficiently remove foreign, damaged, or denatured proteins. This essential function has been a barrier to the overexpression of recombinant proteins in most expression systems. A notable exception is the overexpression in E. coli of recombinant proteins, most of which, however, end-up as "inclusion bodies", i.e., cytoplasmic aggregates of proteins that are inaccessible to the cell's proteasome. "Fusion constructs as protein overexpression vectors" proved to be unparalleled in their ability to cause substantial accumulation of recombinant proteins from plants, animals, and bacteria, as soluble proteins in unicellular cyanobacteria. Recombinant protein levels in the range of 10-20% of the total cellular protein can be achieved. The present work investigated this unique property in the context of recombinant protein stability in Synechocystis sp. PCC 6803 by developing and applying an in vivo cellular tobacco etch virus cleavage system with the objective of separating the target heterologous proteins from their fusion leader sequences. The work provides new insights about the overexpression, cellular stability, and exploitation of transgenes with commercial interest, highly expressed in a cyanobacterial biofactory. The results support the notion that eukaryotic plant- and animal-origin recombinant proteins are unstable, when free in the cyanobacterial cytosol but stable when in a fusion configuration with a highly expressed cyanobacterial native or heterologous protein. Included in this analysis are recombinant proteins of the plant isoprenoid biosynthetic pathway (isoprene synthase, β-phellandrene synthase, geranyl diphosphate synthase), the human interferon protein, as well as prokaryotic proteins (tetanus toxin fragment C and the antibiotic resistance genes kanamycin and chloramphenicol). The future success of synthetic biology approaches with cyanobacteria and other systems would require overexpression of pathway enzymes to attain product volume, and the work reported in this paper sets the foundation for such recombinant pathway enzyme overexpression.
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Affiliation(s)
- Xianan Zhang
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Nico Betterle
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Diego Hidalgo Martinez
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
| | - Anastasios Melis
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, United States
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Jackson HO, Taunt HN, Mordaka PM, Smith AG, Purton S. The Algal Chloroplast as a Testbed for Synthetic Biology Designs Aimed at Radically Rewiring Plant Metabolism. FRONTIERS IN PLANT SCIENCE 2021; 12:708370. [PMID: 34630459 PMCID: PMC8497815 DOI: 10.3389/fpls.2021.708370] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/10/2021] [Indexed: 05/04/2023]
Abstract
Sustainable and economically viable support for an ever-increasing global population requires a paradigm shift in agricultural productivity, including the application of biotechnology to generate future crop plants. Current genetic engineering approaches aimed at enhancing the photosynthetic efficiency or composition of the harvested tissues involve relatively simple manipulations of endogenous metabolism. However, radical rewiring of central metabolism using new-to-nature pathways, so-called "synthetic metabolism", may be needed to really bring about significant step changes. In many cases, this will require re-programming the metabolism of the chloroplast, or other plastids in non-green tissues, through a combination of chloroplast and nuclear engineering. However, current technologies for sophisticated chloroplast engineering ("transplastomics") of plants are limited to just a handful of species. Moreover, the testing of metabolic rewiring in the chloroplast of plant models is often impractical given their obligate phototrophy, the extended time needed to create stable non-chimeric transplastomic lines, and the technical challenges associated with regeneration of whole plants. In contrast, the unicellular green alga, Chlamydomonas reinhardtii is a facultative heterotroph that allows for extensive modification of chloroplast function, including non-photosynthetic designs. Moreover, chloroplast engineering in C. reinhardtii is facile, with the ability to generate novel lines in a matter of weeks, and a well-defined molecular toolbox allows for rapid iterations of the "Design-Build-Test-Learn" (DBTL) cycle of modern synthetic biology approaches. The recent development of combinatorial DNA assembly pipelines for designing and building transgene clusters, simple methods for marker-free delivery of these clusters into the chloroplast genome, and the pre-existing wealth of knowledge regarding chloroplast gene expression and regulation in C. reinhardtii further adds to the versatility of transplastomics using this organism. Herein, we review the inherent advantages of the algal chloroplast as a simple and tractable testbed for metabolic engineering designs, which could then be implemented in higher plants.
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Affiliation(s)
- Harry O. Jackson
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Henry N. Taunt
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Pawel M. Mordaka
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
- *Correspondence: Saul Purton
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Kumar G, Shekh A, Jakhu S, Sharma Y, Kapoor R, Sharma TR. Bioengineering of Microalgae: Recent Advances, Perspectives, and Regulatory Challenges for Industrial Application. Front Bioeng Biotechnol 2020; 8:914. [PMID: 33014997 PMCID: PMC7494788 DOI: 10.3389/fbioe.2020.00914] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/15/2020] [Indexed: 01/14/2023] Open
Abstract
Microalgae, due to their complex metabolic capacity, are being continuously explored for nutraceuticals, pharmaceuticals, and other industrially important bioactives. However, suboptimal yield and productivity of the bioactive of interest in local and robust wild-type strains are of perennial concerns for their industrial applications. To overcome such limitations, strain improvement through genetic engineering could play a decisive role. Though the advanced tools for genetic engineering have emerged at a greater pace, they still remain underused for microalgae as compared to other microorganisms. Pertaining to this, we reviewed the progress made so far in the development of molecular tools and techniques, and their deployment for microalgae strain improvement through genetic engineering. The recent availability of genome sequences and other omics datasets form diverse microalgae species have remarkable potential to guide strategic momentum in microalgae strain improvement program. This review focuses on the recent and significant improvements in the omics resources, mutant libraries, and high throughput screening methodologies helpful to augment research in the model and non-model microalgae. Authors have also summarized the case studies on genetically engineered microalgae and highlight the opportunities and challenges that are emerging from the current progress in the application of genome-editing to facilitate microalgal strain improvement. Toward the end, the regulatory and biosafety issues in the use of genetically engineered microalgae in commercial applications are described.
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Affiliation(s)
- Gulshan Kumar
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Ajam Shekh
- Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, India
| | - Sunaina Jakhu
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Yogesh Sharma
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Ritu Kapoor
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Tilak Raj Sharma
- Division of Crop Science, Indian Council of Agricultural Research, New Delhi, India
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Betterle N, Hidalgo Martinez D, Melis A. Cyanobacterial Production of Biopharmaceutical and Biotherapeutic Proteins. FRONTIERS IN PLANT SCIENCE 2020; 11:237. [PMID: 32194609 PMCID: PMC7062967 DOI: 10.3389/fpls.2020.00237] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Efforts to express human therapeutic proteins in photosynthetic organisms have been described in the literature. Regarding microalgae, most of the research entailed a heterologous transformation of the chloroplast, but transformant cells failed to accumulate the desired recombinant proteins in high quantity. The present work provides methods and DNA construct formulations for over-expressing in photosynthetic cyanobacteria, at the protein level, human-origin bio-pharmaceutical and bio-therapeutic proteins. Proof-of-concept evidence is provided for the design and reduction to practice of "fusion constructs as protein overexpression vectors" for the generation of the bio-therapeutic protein interferon alpha-2 (IFN). IFN is a member of the Type I interferon cytokine family, well-known for its antiviral and anti-proliferative functions. Fusion construct formulations enabled accumulation of IFN up to 12% of total cellular protein in soluble form. In addition, the work reports on the isolation and purification of the fusion IFN protein and preliminary verification of its antiviral activity. Combining the expression and purification protocols developed here, it is possible to produce fairly large quantities of interferon in these photosynthetic microorganisms, generated from sunlight, CO2, and H2O.
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Naghshbandi MP, Tabatabaei M, Aghbashlo M, Aftab MN, Iqbal I. Metabolic Engineering of Microalgae for Biofuel Production. Methods Mol Biol 2019; 1980:153-172. [PMID: 30666564 DOI: 10.1007/7651_2018_205] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Microalgae are considered as promising cell factories for the production of various types of biofuels, including bioethanol, biodiesel, and biohydrogen by using carbon dioxide and sunlight. In spite of unique advantages of these microorganisms, the commercialization of microalgal biofuels has been hindered by poor economic features. Metabolic engineering is among the most promising strategies put forth to overcome this challenge. In this chapter, metabolic pathways involved in lipid and hydrogen production by microalgae are reviewed and discussed. Moreover, metabolic and genetic engineering approaches investigated for improving the rate of lipid (as a feedstock for biodiesel production) and biohydrogen synthesis are presented. Finally, genetic engineering tools and approaches employed for engineering microalgal metabolic pathways are elaborated. A thorough step-by-step protocol for reconstructing the metabolic pathway of various microorganisms including microalgae is also presented.
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Affiliation(s)
- Mohammad Pooya Naghshbandi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Meisam Tabatabaei
- Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran. .,Biofuel Research Team (BRTeam), Karaj, Iran.
| | - Mortaza Aghbashlo
- Department of Mechanical Engineering of Agricultural Machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
| | - Muhammad Nauman Aftab
- Institute of Industrial Biotechnology, Government College University, Lahore, Pakistan
| | - Irfana Iqbal
- Department of Zoology, Lahore College for Women University, Lahore, Pakistan
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Carrera Pacheco SE, Hankamer B, Oey M. Optimising light conditions increases recombinant protein production in Chlamydomonas reinhardtii chloroplasts. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Dyo YM, Purton S. The algal chloroplast as a synthetic biology platform for production of therapeutic proteins. Microbiology (Reading) 2018; 164:113-121. [DOI: 10.1099/mic.0.000599] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Yuliya M. Dyo
- Molecular Research of Microalgae Laboratory, M. A. Ajtkhozhin Institute of Molecular Biology and Biochemistry, Almaty, Kazakhstan
- Department of Biotechnology, Kazakh National Research Technology University, Almaty, Kazakhstan
| | - Saul Purton
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
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Richter LV, Yang H, Yazdani M, Hanson MR, Ahner BA. A downstream box fusion allows stable accumulation of a bacterial cellulase in Chlamydomonas reinhardtii chloroplasts. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:133. [PMID: 29760775 PMCID: PMC5944112 DOI: 10.1186/s13068-018-1127-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/23/2018] [Indexed: 05/17/2023]
Abstract
BACKGROUND We investigated strategies to improve foreign protein accumulation in the chloroplasts of the model algae Chlamydomonas reinhardtii and tested the outcome in both standard culture conditions as well as one pertinent to algal biofuel production. The downstream box (DB) of the TetC or NPTII genes, the first 15 codons following the start codon, was N-terminally fused to the coding region of cel6A, an endoglucanase from Thermobifida fusca. We also employed a chimeric regulatory element, consisting of the 16S rRNA promoter and the atpA 5'UTR, previously reported to enhance protein expression, to regulate the expression of the TetC-cel6A gene. We further investigated the accumulation of TetC-Cel6A under N-deplete growth conditions. RESULTS Both of the DB fusions improved intracellular accumulation of Cel6A in transplastomic C. reinhardtii strains though the TetC DB was much more effective than the NPTII DB. Furthermore, using the chimeric regulatory element, the TetC-Cel6A protein accumulation displayed a significant increase to 0.3% total soluble protein (TSP), whereas NPTII-Cel6A remained too low to quantify. Comparable levels of TetC- and NPTII-cel6A transcripts were observed, which suggests that factors other than transcript abundance mediate the greater TetC-Cel6A accumulation. The TetC-Cel6A accumulation was stable regardless of the growth stage, and the transplastomic strain growth rate was not altered. When transplastomic cells were suspended in N-deplete medium, cellular levels of TetC-Cel6A increased over time along with TSP, and were greater than those in cells suspended in N-replete medium. CONCLUSIONS The DB fusion holds great value as a tool to enhance foreign protein accumulation in C. reinhardtii chloroplasts and its influence is related to translation or other post-transcriptional processes. Our results also suggest that transplastomic protein production can be compatible with algal biofuel production strategies. Cells displayed a consistent accumulation of recombinant protein throughout the growth phase and nitrogen starvation, a strategy used to induce lipid production in algae, led to higher cellular heterologous protein content. The latter result is contrary to what might have been expected a priori and is an important result for the development of future algal biofuel systems, which will likely require co-products for economic sustainability.
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Affiliation(s)
- Lubna V. Richter
- Department of Biological and Environmental Engineering, Cornell University, 111 Wing Drive, Ithaca, NY USA
| | - Huijun Yang
- Department of Biological and Environmental Engineering, Cornell University, 111 Wing Drive, Ithaca, NY USA
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, NY USA
| | - Mohammad Yazdani
- Department of Biological and Environmental Engineering, Cornell University, 111 Wing Drive, Ithaca, NY USA
| | - Maureen R. Hanson
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, NY USA
| | - Beth A. Ahner
- Department of Biological and Environmental Engineering, Cornell University, 111 Wing Drive, Ithaca, NY USA
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Jagadevan S, Banerjee A, Banerjee C, Guria C, Tiwari R, Baweja M, Shukla P. Recent developments in synthetic biology and metabolic engineering in microalgae towards biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:185. [PMID: 29988523 PMCID: PMC6026345 DOI: 10.1186/s13068-018-1181-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/20/2018] [Indexed: 05/03/2023]
Abstract
In the wake of the uprising global energy crisis, microalgae have emerged as an alternate feedstock for biofuel production. In addition, microalgae bear immense potential as bio-cell factories in terms of producing key chemicals, recombinant proteins, enzymes, lipid, hydrogen and alcohol. Abstraction of such high-value products (algal biorefinery approach) facilitates to make microalgae-based renewable energy an economically viable option. Synthetic biology is an emerging field that harmoniously blends science and engineering to help design and construct novel biological systems, with an aim to achieve rationally formulated objectives. However, resources and tools used for such nuclear manipulation, construction of synthetic gene network and genome-scale reconstruction of microalgae are limited. Herein, we present recent developments in the upcoming field of microalgae employed as a model system for synthetic biology applications and highlight the importance of genome-scale reconstruction models and kinetic models, to maximize the metabolic output by understanding the intricacies of algal growth. This review also examines the role played by microalgae as biorefineries, microalgal culture conditions and various operating parameters that need to be optimized to yield biofuel that can be economically competitive with fossil fuels.
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Affiliation(s)
- Sheeja Jagadevan
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004 India
| | - Avik Banerjee
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004 India
| | - Chiranjib Banerjee
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004 India
| | - Chandan Guria
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004 India
| | - Rameshwar Tiwari
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001 India
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian Institute of Technology, Hauz-Khas, New Delhi 110016 India
| | - Mehak Baweja
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001 India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001 India
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Shi J, Huang T, Chai S, Guo Y, Wei J, Dou S, Li L, Liu G. Identification of Reference and Biomarker Proteins in Chlamydomonas reinhardtii Cultured under Different Stress Conditions. Int J Mol Sci 2017; 18:ijms18081822. [PMID: 28829403 PMCID: PMC5578208 DOI: 10.3390/ijms18081822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 11/25/2022] Open
Abstract
Reference proteins and biomarkers are important for the quantitative evaluation of protein abundance. Chlamydomonasreinhardtii was grown under five stress conditions (dark, cold, heat, salt, and glucose supplementation), and the OD750 and total protein contents were evaluated on days 0, 1, 2, 4, and 6 of culture. Antibodies for 20 candidate proteins were generated, and the protein expression patterns were examined by western blotting. Reference protein(s) for each treatment were identified by calculating the Pearson’s correlation coefficient (PCC) between target protein abundance and total protein content. Histone H3, beta tubulin 1 (TUB-1), ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (RBCL), and mitochondrial F1F0 ATP synthase subunit 6 (ATPs-6) were the top reference proteins, because they were expressed stably under multiple stress conditions. The average relative-fold change (ARF) value of each protein was calculated to identify biomarkers. Heat shock protein 90B (HSP90B), flagellar associated protein (FAP127) and ATP synthase CF0 A subunit (ATPs-A) were suitable biomarkers for multiple treatments, while receptor of activated protein kinase C1 (RCK1), biotin carboxylase (BCR1), mitochondrial phosphate carrier protein (MPC1), and rubisco large subunit N-methyltransferase (RMT1) were suitable biomarkers for the dark, cold, heat, and glucose treatments, respectively.
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Affiliation(s)
- Jianan Shi
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Teng Huang
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Shuaijie Chai
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Yalu Guo
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Jian Wei
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Shijuan Dou
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Liyun Li
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
| | - Guozhen Liu
- Institute of Bioenergy, College of Life Sciences, Hebei Agricultural University, Baoding 071001, Hebei, China.
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Sawyer A, Bai Y, Lu Y, Hemschemeier A, Happe T. Compartmentalisation of [FeFe]-hydrogenase maturation in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:1134-1143. [PMID: 28295776 DOI: 10.1111/tpj.13535] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/01/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Molecular hydrogen (H2 ) can be produced in green microalgae by [FeFe]-hydrogenases as a direct product of photosynthesis. The Chlamydomonas reinhardtii hydrogenase HYDA1 contains a catalytic site comprising a classic [4Fe4S] cluster linked to a unique 2Fe sub-cluster. From in vitro studies it appears that the [4Fe4S] cluster is incorporated first by the housekeeping FeS cluster assembly machinery, followed by the 2Fe sub-cluster, whose biosynthesis requires the specific maturases HYDEF and HYDG. To investigate the maturation process in vivo, we expressed HYDA1 from the C. reinhardtii chloroplast and nuclear genomes (with and without a chloroplast transit peptide) in a hydrogenase-deficient mutant strain, and examined the cellular enzymatic hydrogenase activity, as well as in vivo H2 production. The transformants expressing HYDA1 from the chloroplast genome displayed levels of H2 production comparable to the wild type, as did the transformants expressing full-length HYDA1 from the nuclear genome. In contrast, cells equipped with cytoplasm-targeted HYDA1 produced inactive enzyme, which could only be activated in vitro after reconstitution of the [4Fe4S] cluster. This indicates that the HYDA1 FeS cluster can only be built by the chloroplastic FeS cluster assembly machinery. Further, the expression of a bacterial hydrogenase gene, CPI, from the C. reinhardtii chloroplast genome resulted in H2 -producing strains, demonstrating that a hydrogenase with a very different structure can fulfil the role of HYDA1 in vivo and that overexpression of foreign hydrogenases in C. reinhardtii is possible. All chloroplast transformants were stable and no toxic effects were seen from HYDA1 or CPI expression.
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Affiliation(s)
- Anne Sawyer
- AG Photobiotechnologie, Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Yu Bai
- AG Photobiotechnologie, Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, 44801, Bochum, Germany
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yinghua Lu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Anja Hemschemeier
- AG Photobiotechnologie, Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Thomas Happe
- AG Photobiotechnologie, Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, 44801, Bochum, Germany
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Identification of gene transcripts involved in lipid biosynthesis in Chlamydomonas reinhardtii under nitrogen, iron and sulfur deprivation. World J Microbiol Biotechnol 2016; 32:55. [DOI: 10.1007/s11274-016-2008-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/04/2016] [Indexed: 10/22/2022]
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Hlavova M, Turoczy Z, Bisova K. Improving microalgae for biotechnology — From genetics to synthetic biology. Biotechnol Adv 2015; 33:1194-203. [DOI: 10.1016/j.biotechadv.2015.01.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/11/2015] [Accepted: 01/17/2015] [Indexed: 01/01/2023]
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The potential of transgenic green microalgae; a robust photobioreactor to produce recombinant therapeutic proteins. World J Microbiol Biotechnol 2014; 30:2783-96. [PMID: 25115849 DOI: 10.1007/s11274-014-1714-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 07/30/2014] [Indexed: 02/01/2023]
Abstract
Microalgae have been used in food, cosmetic, and biofuel industries as a natural source of lipids, vitamins, pigments and antioxidants for a long time. Green microalgae, as potent photobioreactors, can be considered as an economical expression system to produce recombinant therapeutical proteins at large-scale due to low cost of production and scaling-up capitalization owning to the inexpensive medium requirement, fast growth rate, and the ease of manipulation. These microalgae possess all benefit eukaryotic expression systems including the ability of post-translational modifications required for proper folding and stability of active proteins. Among the many items regarded as recombinant protein production, this review compares the different expression systems with green microalgae like Dunaliella by viewing the nuclear/chloroplast transformation challenges/benefits, related selection markers/reporter genes, and crucial factors/strategies affecting the increase of foreign protein expression in microalgae transformants. Some important factors were discussed regarding the increase of protein yielding in microalgae transformants including: transformation-associated genotypic modifications, endogenous regulatory factors, promoters, codon optimization, enhancer elements, and milking of recombinant protein.
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Light-Induced Production of An Antibody Fragment and Malaria Vaccine Antigen from Chlamydomonas reinhardtii. Processes (Basel) 2014. [DOI: 10.3390/pr2030625] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Rosales-Mendoza S. Future directions for the development of Chlamydomonas-based vaccines. Expert Rev Vaccines 2014; 12:1011-9. [PMID: 24053395 DOI: 10.1586/14760584.2013.825455] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Besides serving as a valuable model in biological sciences, Chamydomonas reinhardtii has been used during the last decade in the biotechnology arena to establish models for the low cost production of vaccines. Antigens from various pathogens including Plasmodium falciparum, foot and mouth disease virus, Staphylococcus aureus, classical swine fever virus (CSFV) as well as some auto-antigens, have been produced in C. reinhardtii. Although some of them have been functionally characterized with promising results, this review identifies future directions for the advancement in the exploitation of this robust and safe vaccine production platform. The present analysis reflects that important immunological implications exist for this system and remain unexplored, including the possible adjuvant effects of algae biomolecules, the effect of bioencapsulation on immunogenicity and the possible development of whole-cell vaccines as an approach to trigger cytotoxic immune responses. Recently described molecular strategies that aim to optimize the expression of nuclear-encoded target antigens are also discussed.
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Affiliation(s)
- Sergio Rosales-Mendoza
- Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6, SLP, 78210, México +52 444 826 2440 +52 444 826 2440
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Sauer MLA, Xu B, Sutton F. Metabolic labeling with stable isotope nitrogen (15N) to follow amino acid and protein turnover of three plastid proteins in Chlamydomonas reinhardtii. Proteome Sci 2014; 12:14. [PMID: 24580857 PMCID: PMC3943399 DOI: 10.1186/1477-5956-12-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/18/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The length of time that a protein remains available to perform its function is significantly influenced by its turnover rate. Knowing the turnover rate of proteins involved in different processes is important to determining how long a function might progress even when the stimulus has been removed and no further synthesis of the particular proteins occurs. In this article, we describe the use of 15N-metabolic labeling coupled to GC-MS to follow the turnover of free amino acids and LC-MS/MS to identify and LC-MS to follow the turnover of specific proteins in Chlamydomonas reinhardtii. RESULTS To achieve the metabolic labeling, the growth medium was formulated with standard Tris acetate phosphate medium (TAP) in which14NH4Cl was replaced with 15NH415NO3 and (14NH4)6Mo7O24.4H2O was replaced with Na2MoO4.2H2O. This medium designated 15N-TAP allowed CC-125 algal cells to grow normally. Mass isotopic distribution revealed successful 15N incorporation into 13 amino acids with approximately 98% labeling efficiency. Tryptic digestion of the 55 kDa SDS-PAGE bands from 14N- and 15N-labeled crude algal protein extracts followed by LC-MS/MS resulted in the identification of 27 proteins. Of these, five displayed peptide sequence confidence levels greater than 95% and protein sequence coverage greater than 25%. These proteins were the RuBisCo large subunit, ATP synthase CF1 alpha and beta subunits, the mitochondrial protein (F1F0 ATP synthase) and the cytosolic protein (S-adenosyl homocysteine hydroxylase). These proteins were present in both labeled and unlabeled samples. Once the newly synthesized 15N-labeled free amino acids and proteins obtained maximum incorporation of the 15N-label, turnover rates were determined after transfer of cells into 14N-TAP medium. The t½ values were determined for the three plastid proteins (RuBisCo, ATP synthase CF1 alpha and beta) by following the reduction of the 15N-fractional abundance over time. CONCLUSION We describe a more rapid and non-radioactive method to measure free amino acid and protein turnover. Our approach is applicable for determination of protein turnover for various proteins, which will lead to a better understanding of the relationship between protein lifetime and functionality.
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Affiliation(s)
| | - Bing Xu
- Plant Science Department, South Dakota State University, Brookings, SD 57007, USA
| | - Fedora Sutton
- Plant Science Department, South Dakota State University, Brookings, SD 57007, USA
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Chen HC, Melis A. Marker-free genetic engineering of the chloroplast in the green microalga Chlamydomonas reinhardtii. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:818-28. [PMID: 23647698 DOI: 10.1111/pbi.12073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/05/2013] [Accepted: 03/20/2013] [Indexed: 05/11/2023]
Abstract
The work applied a transgene expression method based on the replacement of an inactive rbcL gene as the selection marker in Chlamydomonas reinhardtii chloroplasts. The native rbcL gene in strain CC2653 has a point mutation that causes early translation termination, thus resulting in a photosynthesis mutant. Recovery of rbcL function for selection is offered along with the heterologous expression of the alcohol dehydrogenase ADH1 gene from Saccharomyces cerevisiae in the Chlamydomonas chloroplast. The CrCpADH1 gene was inserted via double homologous recombination in the psaB-rbcL chloroplast intergenic region of recipient strain CC2653, using the psaB and rbcL gene sequences for the double homologous recombination. This transformation conferred a functional rbcL gene and expression of the CrCpADH1 transgene in the recipient strain. This method alleviated the need to use antibiotics for selection, resulting in a negligible number of false positives during screening, and attaining a transformation efficiency greater than 90%. The approach also ensured segregation of chloroplast DNA copies, so as to achieve homoplasmy of the transformant chloroplast DNA, with a concomitant elimination of recipient strain Cp DNA. High levels of steady-state CrCpADH1 transcripts were detected in the homoplasmic transformants. However, CrCpADH1 protein levels were attenuated under continuous illumination growth conditions due to oxygen accumulation in the cells. Under conditions of low oxygen partial pressure, or anoxia, accumulation of CrCpADH1 protein in the cells and ethanol in the growth medium was observed. A metabolic pathway for ethanol production is proposed in Chlamydomonas, mediated by the chloroplast-localized CrCpADH1 transgenic enzyme.
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Affiliation(s)
- Hsu-Ching Chen
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
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Wijffels RH, Kruse O, Hellingwerf KJ. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae. Curr Opin Biotechnol 2013; 24:405-13. [DOI: 10.1016/j.copbio.2013.04.004] [Citation(s) in RCA: 285] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/28/2013] [Accepted: 04/10/2013] [Indexed: 11/16/2022]
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Pourmir A, Noor-Mohammadi S, Johannes TW. Production of xylitol by recombinant microalgae. J Biotechnol 2013; 165:178-83. [PMID: 23597921 DOI: 10.1016/j.jbiotec.2013.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/05/2013] [Accepted: 04/09/2013] [Indexed: 11/16/2022]
Abstract
Microalgae have received significant attention recently as a potential low-cost host for the production of next-generation biofuels and natural products. Here we show that the chloroplast genome of the eukaryotic green microalga Chlamydomonas reinhardtii can be genetically engineered to produce xylitol through the introduction of a gene encoding a xylose reductase (XR) from the fungi Neurospora crassa. Increased levels of heterologous protein accumulation and xylitol production were achieved by synthesizing the XR gene in the chloroplast codon bias and by driving expression of the codon-optimized XR gene using a 16S/atpA promoter/5'-UTR fusion. These results demonstrate the feasibility of engineering microalgae to produce xylitol, and show the importance of codon optimizing the XR gene and using the 16S/atpA promoter/5'-UTR fusion to express XR in the chloroplast of C. reinhardtii.
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Affiliation(s)
- Azadeh Pourmir
- Department of Chemical Engineering, The University of Tulsa, 800 S. Tucker Drive, Tulsa, OK 74104, USA
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Rosales-Mendoza S, Paz-Maldonado LMT, Soria-Guerra RE. Chlamydomonas reinhardtii as a viable platform for the production of recombinant proteins: current status and perspectives. PLANT CELL REPORTS 2012; 31:479-94. [PMID: 22080228 DOI: 10.1007/s00299-011-1186-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 05/03/2023]
Abstract
Chlamydomonas reinhardtii has many advantages compared with traditional systems for the molecular farming of recombinant proteins. These include low production costs, rapid scalability at pilot level, absence of human pathogens and the ability to fold and assemble complex proteins accurately. Currently, the successful expression of several proteins with pharmaceutical relevance has been reported from the nuclear and the chloroplastic genome of this alga, demonstrating its usefulness for biotechnological applications. However, several factors affect the level of recombinant protein expression in Chlamydomonas such as enhancer elements, codon dependency, sensitivity to proteases and transformation-associated genotypic modification. The present review outlines a number of strategies to increase protein yields and summarizes recent achievements in algal protein production including biopharmaceuticals such as vaccines, antibodies, hormones and enzymes with implications on health-related approaches. The current status of bioreactor developments for algal culture and the challenges of scale-up and optimization processes are also discussed.
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Affiliation(s)
- Sergio Rosales-Mendoza
- Laboratorio de Biofarmacéuticos Recombinantes, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6, 78210 San Luis Potosí, SLP, Mexico.
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Bally J, Job C, Belghazi M, Job D. Metabolic adaptation in transplastomic plants massively accumulating recombinant proteins. PLoS One 2011; 6:e25289. [PMID: 21966485 PMCID: PMC3178635 DOI: 10.1371/journal.pone.0025289] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 08/31/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. METHODOLOGY/PRINCIPAL FINDINGS Here we used proteomics to characterize tobacco (Nicotiana tabacum) plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD) or a green fluorescent protein (GFP). While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO(2) metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. CONCLUSIONS/SIGNIFICANCE The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation.
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Affiliation(s)
- Julia Bally
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
| | - Claudette Job
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
| | - Maya Belghazi
- Centre d'Analyse Protéomique de Marseille, Institut Fédératif de Recherche Jean Roche, Marseille, France
| | - Dominique Job
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
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Maliga P, Bock R. Plastid biotechnology: food, fuel, and medicine for the 21st century. PLANT PHYSIOLOGY 2011; 155:1501-10. [PMID: 21239622 PMCID: PMC3091108 DOI: 10.1104/pp.110.170969] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 01/12/2011] [Indexed: 05/18/2023]
Affiliation(s)
- Pal Maliga
- Waksman Institute, Rutgers University, Piscataway, New Jersey 08854, USA.
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