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Carrera-Pacheco SE, Hankamer B, Oey M. Environmental and nuclear influences on microalgal chloroplast gene expression. TRENDS IN PLANT SCIENCE 2023; 28:955-967. [PMID: 37080835 DOI: 10.1016/j.tplants.2023.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/09/2023] [Accepted: 03/18/2023] [Indexed: 05/03/2023]
Abstract
Microalgal chloroplasts, such as those of the model organism Chlamydomonas reinhardtii, are emerging as a new platform to produce recombinant proteins, including industrial enzymes, diagnostics, as well as animal and human therapeutics. Improving transgene expression and final recombinant protein yields, at laboratory and industrial scales, require optimization of both environmental and cellular factors. Most studies on C. reinhardtii have focused on optimization of cellular factors. Here, we review the regulatory influences of environmental factors, including light (cycle time, intensity, and quality), carbon source (CO2 and organic), and temperature. In particular, we summarize their influence via the redox state, cis-elements, and trans-factors on biomass and recombinant protein production to support the advancement of emerging large-scale light-driven biotechnology applications.
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Affiliation(s)
- Saskya E Carrera-Pacheco
- Centro de Investigación Biomédica (CENBIO), Facultad de Ciencias de la Salud Eugenio Espejo, Universidad UTE, Quito 170527, Ecuador
| | - Ben Hankamer
- The University of Queensland, Institute for Molecular Bioscience, 306 Carmody Road, St Lucia, Australia.
| | - Melanie Oey
- The University of Queensland, Institute for Molecular Bioscience, 306 Carmody Road, St Lucia, Australia.
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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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Oberleitner L, Poschmann G, Macorano L, Schott-Verdugo S, Gohlke H, Stühler K, Nowack ECM. The Puzzle of Metabolite Exchange and Identification of Putative Octotrico Peptide Repeat Expression Regulators in the Nascent Photosynthetic Organelles of Paulinella chromatophora. Front Microbiol 2020; 11:607182. [PMID: 33329499 PMCID: PMC7729196 DOI: 10.3389/fmicb.2020.607182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022] Open
Abstract
The endosymbiotic acquisition of mitochondria and plastids more than one billion years ago was central for the evolution of eukaryotic life. However, owing to their ancient origin, these organelles provide only limited insights into the initial stages of organellogenesis. The cercozoan amoeba Paulinella chromatophora contains photosynthetic organelles-termed chromatophores-that evolved from a cyanobacterium ∼100 million years ago, independently from plastids in plants and algae. Despite the more recent origin of the chromatophore, it shows tight integration into the host cell. It imports hundreds of nucleus-encoded proteins, and diverse metabolites are continuously exchanged across the two chromatophore envelope membranes. However, the limited set of chromatophore-encoded solute transporters appears insufficient for supporting metabolic connectivity or protein import. Furthermore, chromatophore-localized biosynthetic pathways as well as multiprotein complexes include proteins of dual genetic origin, suggesting that mechanisms evolved that coordinate gene expression levels between chromatophore and nucleus. These findings imply that similar to the situation in mitochondria and plastids, also in P. chromatophora nuclear factors evolved that control metabolite exchange and gene expression in the chromatophore. Here we show by mass spectrometric analyses of enriched insoluble protein fractions that, unexpectedly, nucleus-encoded transporters are not inserted into the chromatophore inner envelope membrane. Thus, despite the apparent maintenance of its barrier function, canonical metabolite transporters are missing in this membrane. Instead we identified several expanded groups of short chromatophore-targeted orphan proteins. Members of one of these groups are characterized by a single transmembrane helix, and others contain amphipathic helices. We hypothesize that these proteins are involved in modulating membrane permeability. Thus, the mechanism generating metabolic connectivity of the chromatophore fundamentally differs from the one for mitochondria and plastids, but likely rather resembles the poorly understood mechanism in various bacterial endosymbionts in plants and insects. Furthermore, our mass spectrometric analysis revealed an expanded family of chromatophore-targeted helical repeat proteins. These proteins show similar domain architectures as known organelle-targeted expression regulators of the octotrico peptide repeat type in algae and plants. Apparently these chromatophore-targeted proteins evolved convergently to plastid-targeted expression regulators and are likely involved in gene expression control in the chromatophore.
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Affiliation(s)
- Linda Oberleitner
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Gereon Poschmann
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Luis Macorano
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stephan Schott-Verdugo
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Faculty of Engineering, Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Talca, Chile
| | - Holger Gohlke
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Jülich Supercomputing Centre, John von Neumann Institute for Computing, Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Kai Stühler
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Molecular Proteomics Laboratory, Biologisch-Medizinisches Forschungszentrum, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Eva C. M. Nowack
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Assembly of Mitochondrial Complex I Requires the Low-Complexity Protein AMC1 in Chlamydomonas reinhardtii. Genetics 2020; 214:895-911. [PMID: 32075865 DOI: 10.1534/genetics.120.303029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/05/2020] [Indexed: 11/18/2022] Open
Abstract
Complex I is the first enzyme involved in the mitochondrial electron transport chain. With >40 subunits of dual genetic origin, the biogenesis of complex I is highly intricate and poorly understood. We used Chlamydomonas reinhardtii as a model system to reveal factors involved in complex I biogenesis. Two insertional mutants, displaying a complex I assembly defect characterized by the accumulation of a 700 kDa subcomplex, were analyzed. Genetic analyses showed these mutations were allelic and mapped to the gene AMC1 (Cre16.g688900) encoding a low-complexity protein of unknown function. The complex I assembly and activity in the mutant was restored by complementation with the wild-type gene, confirming AMC1 is required for complex I biogenesis. The N terminus of AMC1 targets a reporter protein to yeast mitochondria, implying that AMC1 resides and functions in the Chlamydomonas mitochondria. Accordingly, in both mutants, loss of AMC1 function results in decreased abundance of the mitochondrial nd4 transcript, which encodes the ND4 membrane subunit of complex I. Loss of ND4 in a mitochondrial nd4 mutant is characterized by a membrane arm assembly defect, similar to that exhibited by loss of AMC1. These results suggest AMC1 is required for the production of mitochondrially-encoded complex I subunits, specifically ND4. We discuss the possible modes of action of AMC1 in mitochondrial gene expression and complex I biogenesis.
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Wittkopp TM, Saroussi S, Yang W, Johnson X, Kim RG, Heinnickel ML, Russell JJ, Phuthong W, Dent RM, Broeckling CD, Peers G, Lohr M, Wollman FA, Niyogi KK, Grossman AR. GreenCut protein CPLD49 of Chlamydomonas reinhardtii associates with thylakoid membranes and is required for cytochrome b 6 f complex accumulation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:1023-1037. [PMID: 29602195 DOI: 10.1111/tpj.13915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 02/23/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
The GreenCut encompasses a suite of nucleus-encoded proteins with orthologs among green lineage organisms (plants, green algae), but that are absent or poorly conserved in non-photosynthetic/heterotrophic organisms. In Chlamydomonas reinhardtii, CPLD49 (Conserved in Plant Lineage and Diatoms49) is an uncharacterized GreenCut protein that is critical for maintaining normal photosynthetic function. We demonstrate that a cpld49 mutant has impaired photoautotrophic growth under high-light conditions. The mutant exhibits a nearly 90% reduction in the level of the cytochrome b6 f complex (Cytb6 f), which impacts linear and cyclic electron transport, but does not compromise the ability of the strain to perform state transitions. Furthermore, CPLD49 strongly associates with thylakoid membranes where it may be part of a membrane protein complex with another GreenCut protein, CPLD38; a mutant null for CPLD38 also impacts Cytb6 f complex accumulation. We investigated several potential functions of CPLD49, with some suggested by protein homology. Our findings are congruent with the hypothesis that CPLD38 and CPLD49 are part of a novel thylakoid membrane complex that primarily modulates accumulation, but also impacts the activity of the Cytb6 f complex. Based on motifs of CPLD49 and the activities of other CPLD49-like proteins, we suggest a role for this putative dehydrogenase in the synthesis of a lipophilic thylakoid membrane molecule or cofactor that influences the assembly and activity of Cytb6 f.
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Affiliation(s)
- Tyler M Wittkopp
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Shai Saroussi
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Wenqiang Yang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Xenie Johnson
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint Paul lez Durance, France
| | - Rick G Kim
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Mark L Heinnickel
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - James J Russell
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Witchukorn Phuthong
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Rachel M Dent
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720-3102, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Corey D Broeckling
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523, USA
| | - Graham Peers
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Martin Lohr
- Institut für Molekulare Physiologie - Pflanzenbiochemie, Johannes Gutenberg-Universität, 55099, Mainz, Germany
| | | | - Krishna K Niyogi
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720-3102, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
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