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Zhang L, Ruan J, Gao F, Xin Q, Che LP, Cai L, Liu Z, Kong M, Rochaix JD, Mi H, Peng L. Thylakoid protein FPB1 synergistically cooperates with PAM68 to promote CP47 biogenesis and Photosystem II assembly. Nat Commun 2024; 15:3122. [PMID: 38600073 PMCID: PMC11006888 DOI: 10.1038/s41467-024-46863-y] [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] [Received: 03/08/2023] [Accepted: 03/13/2024] [Indexed: 04/12/2024] Open
Abstract
In chloroplasts, insertion of proteins with multiple transmembrane domains (TMDs) into thylakoid membranes usually occurs in a co-translational manner. Here, we have characterized a thylakoid protein designated FPB1 (Facilitator of PsbB biogenesis1) which together with a previously reported factor PAM68 (Photosynthesis Affected Mutant68) is involved in assisting the biogenesis of CP47, a subunit of the Photosystem II (PSII) core. Analysis by ribosome profiling reveals increased ribosome stalling when the last TMD segment of CP47 emerges from the ribosomal tunnel in fpb1 and pam68. FPB1 interacts with PAM68 and both proteins coimmunoprecipitate with SecY/E and Alb3 as well as with some ribosomal components. Thus, our data indicate that, in coordination with the SecY/E translocon and the Alb3 integrase, FPB1 synergistically cooperates with PAM68 to facilitate the co-translational integration of the last two CP47 TMDs and the large loop between them into thylakoids and the PSII core complex.
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Affiliation(s)
- Lin Zhang
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Junxiang Ruan
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Fudan Gao
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Qiang Xin
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Li-Ping Che
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Lujuan Cai
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Zekun Liu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Mengmeng Kong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai, 200032, China
| | - Jean-David Rochaix
- Departments of Molecular Biology and Plant Biology, University of Geneva, 1211, Geneva, Switzerland
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai, 200032, China
| | - Lianwei Peng
- Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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2
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Keller JM, Frieboes MJ, Jödecke L, Kappel S, Wulff N, Rindfleisch T, Sandoval-Ibanez O, Gerlach I, Thiele W, Bock R, Eirich J, Finkemeier I, Schünemann D, Zoschke R, Schöttler MA, Armbruster U. Eukaryote-specific assembly factor DEAP2 mediates an early step of photosystem II assembly in Arabidopsis. PLANT PHYSIOLOGY 2023; 193:1970-1986. [PMID: 37555435 PMCID: PMC10602607 DOI: 10.1093/plphys/kiad446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 08/10/2023]
Abstract
The initial step of oxygenic photosynthesis is the thermodynamically challenging extraction of electrons from water and the release of molecular oxygen. This light-driven process, which is the basis for most life on Earth, is catalyzed by photosystem II (PSII) within the thylakoid membrane of photosynthetic organisms. The biogenesis of PSII requires a controlled step-wise assembly process of which the early steps are considered to be highly conserved between plants and their cyanobacterial progenitors. This assembly process involves auxiliary proteins, which are likewise conserved. In the present work, we used Arabidopsis (Arabidopsis thaliana) as a model to show that in plants, a eukaryote-exclusive assembly factor facilitates the early assembly step, during which the intrinsic antenna protein CP47 becomes associated with the PSII reaction center (RC) to form the RC47 intermediate. This factor, which we named DECREASED ELECTRON TRANSPORT AT PSII (DEAP2), works in concert with the conserved PHOTOSYNTHESIS AFFECTED MUTANT 68 (PAM68) assembly factor. The deap2 and pam68 mutants showed similar defects in PSII accumulation and assembly of the RC47 intermediate. The combined lack of both proteins resulted in a loss of functional PSII and the inability of plants to grow photoautotrophically on the soil. While overexpression of DEAP2 partially rescued the pam68 PSII accumulation phenotype, this effect was not reciprocal. DEAP2 accumulated at 20-fold higher levels than PAM68, together suggesting that both proteins have distinct functions. In summary, our results uncover eukaryotic adjustments to the PSII assembly process, which involve the addition of DEAP2 for the rapid progression from RC to RC47.
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Affiliation(s)
- Jakob-Maximilian Keller
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Maureen Julia Frieboes
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Ludwig Jödecke
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Sandrine Kappel
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Natalia Wulff
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Tobias Rindfleisch
- Computational Biology Unit, Department of Chemistry, University of Bergen, 5008 Bergen, Norway
| | - Omar Sandoval-Ibanez
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Ines Gerlach
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany
| | - Danja Schünemann
- Molecular Biology of Plant Organelles, Ruhr University Bochum, 44780 Bochum, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, 14476 Potsdam, Germany
- Institute of Molecular Photosynthesis, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- CEPLAS - Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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3
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Small I, Melonek J, Bohne AV, Nickelsen J, Schmitz-Linneweber C. Plant organellar RNA maturation. THE PLANT CELL 2023; 35:1727-1751. [PMID: 36807982 PMCID: PMC10226603 DOI: 10.1093/plcell/koad049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/17/2023] [Indexed: 05/30/2023]
Abstract
Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery-and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in.
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Affiliation(s)
- Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | | | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
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4
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Wang F, Dischinger K, Westrich LD, Meindl I, Egidi F, Trösch R, Sommer F, Johnson X, Schroda M, Nickelsen J, Willmund F, Vallon O, Bohne AV. One-helix protein 2 is not required for the synthesis of photosystem II subunit D1 in Chlamydomonas. PLANT PHYSIOLOGY 2023; 191:1612-1633. [PMID: 36649171 PMCID: PMC10022639 DOI: 10.1093/plphys/kiad015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
In land plants and cyanobacteria, co-translational association of chlorophyll (Chl) to the nascent D1 polypeptide, a reaction center protein of photosystem II (PSII), requires a Chl binding complex consisting of a short-chain dehydrogenase (high chlorophyll fluorescence 244 [HCF244]/uncharacterized protein 39 [Ycf39]) and one-helix proteins (OHP1 and OHP2 in chloroplasts) of the light-harvesting antenna complex superfamily. Here, we show that an ohp2 mutant of the green alga Chlamydomonas (Chlamydomonas reinhardtii) fails to accumulate core PSII subunits, in particular D1 (encoded by the psbA mRNA). Extragenic suppressors arose at high frequency, suggesting the existence of another route for Chl association to PSII. The ohp2 mutant was complemented by the Arabidopsis (Arabidopsis thaliana) ortholog. In contrast to land plants, where psbA translation is prevented in the absence of OHP2, ribosome profiling experiments showed that the Chlamydomonas mutant translates the psbA transcript over its full length. Pulse labeling suggested that D1 is degraded during or immediately after translation. The translation of other PSII subunits was affected by assembly-controlled translational regulation. Proteomics showed that HCF244, a translation factor which associates with and is stabilized by OHP2 in land plants, still partly accumulates in the Chlamydomonas ohp2 mutant, explaining the persistence of psbA translation. Several Chl biosynthesis enzymes overaccumulate in the mutant membranes. Partial inactivation of a D1-degrading protease restored a low level of PSII activity in an ohp2 background, but not photoautotrophy. Taken together, our data suggest that OHP2 is not required for psbA translation in Chlamydomonas, but is necessary for D1 stabilization.
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Affiliation(s)
- Fei Wang
- Molecular Plant Sciences, LMU Munich, Planegg-Martinsried 82152, Germany
- UMR 7141, Centre National de la Recherche Scientifique/Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | | | - Lisa Désirée Westrich
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Irene Meindl
- Molecular Plant Sciences, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Felix Egidi
- Molecular Plant Sciences, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Raphael Trösch
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Frederik Sommer
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Xenie Johnson
- UMR 7141, Centre National de la Recherche Scientifique/Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Joerg Nickelsen
- Molecular Plant Sciences, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Olivier Vallon
- UMR 7141, Centre National de la Recherche Scientifique/Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
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5
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Gao LL, Hong ZH, Wang Y, Wu GZ. Chloroplast proteostasis: A story of birth, life, and death. PLANT COMMUNICATIONS 2023; 4:100424. [PMID: 35964157 PMCID: PMC9860172 DOI: 10.1016/j.xplc.2022.100424] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 06/02/2023]
Abstract
Protein homeostasis (proteostasis) is a dynamic balance of protein synthesis and degradation. Because of the endosymbiotic origin of chloroplasts and the massive transfer of their genetic information to the nucleus of the host cell, many protein complexes in the chloroplasts are constituted from subunits encoded by both genomes. Hence, the proper function of chloroplasts relies on the coordinated expression of chloroplast- and nucleus-encoded genes. The biogenesis and maintenance of chloroplast proteostasis are dependent on synthesis of chloroplast-encoded proteins, import of nucleus-encoded chloroplast proteins from the cytosol, and clearance of damaged or otherwise undesired "old" proteins. This review focuses on the regulation of chloroplast proteostasis, its interaction with proteostasis of the cytosol, and its retrograde control over nuclear gene expression. We also discuss significant issues and perspectives for future studies and potential applications for improving the photosynthetic performance and stress tolerance of crops.
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Affiliation(s)
- Lin-Lin Gao
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Zheng-Hui Hong
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yinsong Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Guo-Zhang Wu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
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6
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Zhou D, Mehmood F, Lin P, Cheng T, Wang H, Shi S, Zhang J, Meng J, Zheng K, Poczai P. Characterization of the Evolutionary Pressure on Anisodus tanguticus Maxim. with Complete Chloroplast Genome Sequence. Genes (Basel) 2022; 13:2125. [PMID: 36421800 PMCID: PMC9690199 DOI: 10.3390/genes13112125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/06/2022] [Accepted: 11/07/2022] [Indexed: 10/15/2023] Open
Abstract
Anisodus tanguticus Maxim. (Solanaceae), a traditional endangered Tibetan herb, is endemic to the Qinghai-Tibet Plateau. Here, we report the de novo assembled chloroplast (cp) genome sequences of A. tanguticus (155,765 bp). The cp contains a pair of inverted repeated (IRa and IRb) regions of 25,881 bp that are separated by a large single copy (LSC) region (86,516 bp) and a small single copy SSC (17,487 bp) region. A total of 132 functional genes were annotated in the cp genome, including 87 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Moreover, 199 simple sequence repeats (SSR) and 65 repeat structures were detected. Comparative plastome analyses revealed a conserved gene order and high similarity of protein-coding sequences. The A. tanguticus cp genome exhibits contraction and expansion, which differs from Przewalskia tangutica and other related Solanaceae species. We identified 30 highly polymorphic regions, mostly belonging to intergenic spacer regions (IGS), which may be suitable for the development of robust and cost-effective markers for inferring the phylogeny of the genus Anisodus and family Solanaceae. Analysis of the Ka/Ks ratios of the Hyoscyameae tribe revealed significant positive selection exerted on the cemA, rpoC2, and clpP genes, which suggests that protein metabolism may be an important strategy for A. tanguticus and other species in Hyoscyameae in adapting to the adverse environment on the Qinghai-Tibetan Plateau. Phylogenetic analysis revealed that A. tanguticus clustered closer with Hyoscyamus niger than P. tangutica. Our results provide reliable genetic information for future exploration of the taxonomy and phylogenetic evolution of the Hyoscyameae tribe and related species.
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Affiliation(s)
- Dangwei Zhou
- The College of Pharmacy, Qinghai Nationalities University, Xining 810007, China
- Key Laboratory of Adaptation and Evolution of Plateau Biota (AEPB), Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Furrukh Mehmood
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
- Department of Biochemistry, Faculty of Sciences, University of Sialkot, Daska Road, Punjab 51040, Pakistan
| | - Pengcheng Lin
- The College of Pharmacy, Qinghai Nationalities University, Xining 810007, China
| | - Tingfeng Cheng
- Key Laboratory of Adaptation and Evolution of Plateau Biota (AEPB), Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Huan Wang
- Key Laboratory of Adaptation and Evolution of Plateau Biota (AEPB), Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Shenbo Shi
- Key Laboratory of Adaptation and Evolution of Plateau Biota (AEPB), Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Jinkui Zhang
- The College of Pharmacy, Qinghai Nationalities University, Xining 810007, China
| | - Jing Meng
- The College of Pharmacy, Qinghai Nationalities University, Xining 810007, China
| | - Kun Zheng
- The College of Pharmacy, Qinghai Nationalities University, Xining 810007, China
| | - Péter Poczai
- Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland
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7
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Fages‐Lartaud M, Hundvin K, Hohmann‐Marriott MF. Mechanisms governing codon usage bias and the implications for protein expression in the chloroplast of Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:919-945. [PMID: 36071273 PMCID: PMC9828097 DOI: 10.1111/tpj.15970] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 05/30/2023]
Abstract
Chloroplasts possess a considerably reduced genome that is decoded via an almost minimal set of tRNAs. These features make an excellent platform for gaining insights into fundamental mechanisms that govern protein expression. Here, we present a comprehensive and revised perspective of the mechanisms that drive codon selection in the chloroplast of Chlamydomonas reinhardtii and the functional consequences for protein expression. In order to extract this information, we applied several codon usage descriptors to genes with different expression levels. We show that highly expressed genes strongly favor translationally optimal codons, while genes with lower functional importance are rather affected by directional mutational bias. We demonstrate that codon optimality can be deduced from codon-anticodon pairing affinity and, for a small number of amino acids (leucine, arginine, serine, and isoleucine), tRNA concentrations. Finally, we review, analyze, and expand on the impact of codon usage on protein yield, secondary structures of mRNA, translation initiation and termination, and amino acid composition of proteins, as well as cotranslational protein folding. The comprehensive analysis of codon choice provides crucial insights into heterologous gene expression in the chloroplast of C. reinhardtii, which may also be applicable to other chloroplast-containing organisms and bacteria.
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Affiliation(s)
- Maxime Fages‐Lartaud
- Department of BiotechnologyNorwegian University of Science and TechnologyTrondheimN‐7491Norway
| | - Kristoffer Hundvin
- Department of BiotechnologyNorwegian University of Science and TechnologyTrondheimN‐7491Norway
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8
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Sandoval-Ibáñez O, Rolo D, Ghandour R, Hertle AP, Armarego-Marriott T, Sampathkumar A, Zoschke R, Bock R. De-etiolation-induced protein 1 (DEIP1) mediates assembly of the cytochrome b 6f complex in Arabidopsis. Nat Commun 2022; 13:4045. [PMID: 35831297 PMCID: PMC9279372 DOI: 10.1038/s41467-022-31758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/01/2022] [Indexed: 11/26/2022] Open
Abstract
The conversion of light energy to chemical energy by photosynthesis requires the concerted action of large protein complexes in the thylakoid membrane. Recent work has provided fundamental insights into the three-dimensional structure of these complexes, but how they are assembled from hundreds of parts remains poorly understood. Particularly little is known about the biogenesis of the cytochrome b6f complex (Cytb6f), the redox-coupling complex that interconnects the two photosystems. Here we report the identification of a factor that guides the assembly of Cytb6f in thylakoids of chloroplasts. The protein, DE-ETIOLATION-INDUCED PROTEIN 1 (DEIP1), resides in the thylakoid membrane and is essential for photoautotrophic growth. Knock-out mutants show a specific loss of Cytb6f, and are defective in complex assembly. We demonstrate that DEIP1 interacts with the two cytochrome subunits of the complex, PetA and PetB, and mediates the assembly of intermediates in Cytb6f biogenesis. The identification of DEIP1 provides an entry point into the study of the assembly pathway of a crucial complex in photosynthetic electron transfer. The Cytb6f complex is a multi-subunit enzyme that couples the two photosystems during the light reactions of photosynthesis. Here the authors show that the thylakoid-localized DEIP1 protein interacts with the PetA and PetB subunits, and is essential for Cytb6f complex assembly in Arabidopsis.
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Affiliation(s)
- Omar Sandoval-Ibáñez
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - David Rolo
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Rabea Ghandour
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Alexander P Hertle
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Tegan Armarego-Marriott
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Arun Sampathkumar
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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9
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Zhu D, Xiong H, Wu J, Zheng C, Lu D, Zhang L, Xu X. Protein Targeting Into the Thylakoid Membrane Through Different Pathways. Front Physiol 2022; 12:802057. [PMID: 35095563 PMCID: PMC8790069 DOI: 10.3389/fphys.2021.802057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/07/2021] [Indexed: 01/19/2023] Open
Abstract
In higher plants, chloroplasts are essential semi-autonomous organelles with complex compartments. As part of these sub-organellar compartments, the sheet-like thylakoid membranes contain abundant light-absorbing chlorophylls bound to the light-harvesting proteins and to some of the reaction center proteins. About half of the thylakoid membrane proteins are encoded by nuclear genes and synthesized in the cytosol as precursors before being imported into the chloroplast. After translocation across the chloroplast envelope by the Toc/Tic system, these proteins are subsequently inserted into or translocated across the thylakoid membranes through distinct pathways. The other half of thylakoid proteins are encoded by the chloroplast genome, synthesized in the stroma and integrated into the thylakoid through a cotranslational process. Much progress has been made in identification and functional characterization of new factors involved in protein targeting into the thylakoids, and new insights into this process have been gained. In this review, we introduce the distinct transport systems mediating the translocation of substrate proteins from chloroplast stroma to the thylakoid membrane, and present the recent advances in the identification of novel components mediating these pathways. Finally, we raise some unanswered questions involved in the targeting of chloroplast proteins into the thylakoid membrane, along with perspectives for future research.
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Affiliation(s)
- Dan Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Haibo Xiong
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Jianghao Wu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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10
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Kong M, Wu Y, Wang Z, Qu W, Lan Y, Chen X, Liu Y, Shahnaz P, Yang Z, Yu Q, Mi H. A Novel Chloroplast Protein RNA Processing 8 Is Required for the Expression of Chloroplast Genes and Chloroplast Development in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2021; 12:700975. [PMID: 34956248 PMCID: PMC8695849 DOI: 10.3389/fpls.2021.700975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
Chloroplast development involves the coordinated expression of both plastids- and nuclear-encoded genes in higher plants. However, the underlying mechanism still remains largely unknown. In this study, we isolated and characterized an Arabidopsis mutant with an albino lethality phenotype named RNA processing 8 (rp8). Genetic complementation analysis demonstrated that the gene AT4G37920 (RP8) was responsible for the mutated phenotype. The RP8 gene was strongly expressed in photosynthetic tissues at both transcription and translation protein levels. The RP8 protein is localized in the chloroplast and associated with the thylakoid. Disruption of the RP8 gene led to a defect in the accumulation of the rpoA mature transcript, which reduced the level of the RpoA protein, and affected the transcription of PEP-dependent genes. The abundance of the chloroplast rRNA, including 23S, 16S, 4.5S, and 5S rRNA, were reduced in the rp8 mutant, respectively, and the amounts of chloroplast ribosome proteins, such as, PRPS1(uS1c), PRPS5(uS5c), PRPL2 (uL2c), and PRPL4 (uL4c), were substantially decreased in the rp8 mutant, which indicated that knockout of RP8 seriously affected chloroplast translational machinery. Accordingly, the accumulation of photosynthetic proteins was seriously reduced. Taken together, these results indicate that the RP8 protein plays an important regulatory role in the rpoA transcript processing, which is required for the expression of chloroplast genes and chloroplast development in Arabidopsis.
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Affiliation(s)
- Mengmeng Kong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yaozong Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ziyuan Wang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Wantong Qu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xin Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yanyun Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Perveen Shahnaz
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Zhongnan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Qingbo Yu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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11
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Shirokikh NE. Translation complex stabilization on messenger RNA and footprint profiling to study the RNA responses and dynamics of protein biosynthesis in the cells. Crit Rev Biochem Mol Biol 2021; 57:261-304. [PMID: 34852690 DOI: 10.1080/10409238.2021.2006599] [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] [Indexed: 01/28/2023]
Abstract
During protein biosynthesis, ribosomes bind to messenger (m)RNA, locate its protein-coding information, and translate the nucleotide triplets sequentially as codons into the corresponding sequence of amino acids, forming proteins. Non-coding mRNA features, such as 5' and 3' untranslated regions (UTRs), start sites or stop codons of different efficiency, stretches of slower or faster code and nascent polypeptide interactions can alter the translation rates transcript-wise. Most of the homeostatic and signal response pathways of the cells converge on individual mRNA control, as well as alter the global translation output. Among the multitude of approaches to study translational control, one of the most powerful is to infer the locations of translational complexes on mRNA based on the mRNA fragments protected by these complexes from endonucleolytic hydrolysis, or footprints. Translation complex profiling by high-throughput sequencing of the footprints allows to quantify the transcript-wise, as well as global, alterations of translation, and uncover the underlying control mechanisms by attributing footprint locations and sizes to different configurations of the translational complexes. The accuracy of all footprint profiling approaches critically depends on the fidelity of footprint generation and many methods have emerged to preserve certain or multiple configurations of the translational complexes, often in challenging biological material. In this review, a systematic summary of approaches to stabilize translational complexes on mRNA for footprinting is presented and major findings are discussed. Future directions of translation footprint profiling are outlined, focusing on the fidelity and accuracy of inference of the native in vivo translation complex distribution on mRNA.
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Affiliation(s)
- Nikolay E Shirokikh
- Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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12
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Anderson SA, Satyanarayan MB, Wessendorf RL, Lu Y, Fernandez DE. A homolog of GuidedEntry of Tail-anchored proteins3 functions in membrane-specific protein targeting in chloroplasts of Arabidopsis. THE PLANT CELL 2021; 33:2812-2833. [PMID: 34021351 PMCID: PMC8408437 DOI: 10.1093/plcell/koab145] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/18/2021] [Indexed: 05/12/2023]
Abstract
The chloroplasts and mitochondria of photosynthetic eukaryotes contain proteins that are closely related to cytosolic Guided Entry of Tail-anchored proteins3 (Get3). Get3 is a targeting factor that efficiently escorts tail-anchored (TA) proteins to the ER. Because other components of the cytosolic-targeting pathway appear to be absent in organelles, previous investigators have asserted that organellar Get3 homologs are unlikely to act as targeting factors. However, we show here both that the Arabidopsis thaliana chloroplast homolog designated as GET3B is structurally similar to cytosolic Get3 proteins and that it selectively binds a thylakoid-localized TA protein. Based on genetic interactions between a get3b mutation and mutations affecting the chloroplast signal recognition particle-targeting pathway, as well as changes in the abundance of photosynthesis-related proteins in mutant plants, we propose that GET3B acts primarily to direct proteins to the thylakoids. Furthermore, through molecular complementation experiments, we show that function of GET3B depends on its ability to hydrolyze ATP, and this is consistent with action as a targeting factor. We propose that GET3B and related organellar Get3 homologs play a role that is analogous to that of cytosolic Get3 proteins, and that GET3B acts as a targeting factor in the chloroplast stroma to deliver TA proteins in a membrane-specific manner.
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Affiliation(s)
- Stacy A. Anderson
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Manasa B. Satyanarayan
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008, USA
| | - Ryan L. Wessendorf
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008, USA
| | - Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008, USA
| | - Donna E. Fernandez
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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13
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Fu HY, Ghandour R, Ruf S, Zoschke R, Bock R, Schöttler MA. The availability of neither D2 nor CP43 limits the biogenesis of photosystem II in tobacco. PLANT PHYSIOLOGY 2021; 185:1111-1130. [PMID: 33793892 PMCID: PMC8133689 DOI: 10.1093/plphys/kiaa052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
The pathway of photosystem II (PSII) assembly is well understood, and multiple auxiliary proteins supporting it have been identified, but little is known about rate-limiting steps controlling PSII biogenesis. In the cyanobacterium Synechocystis PCC6803 and the green alga Chlamydomonas reinhardtii, indications exist that the biosynthesis of the chloroplast-encoded D2 reaction center subunit (PsbD) limits PSII accumulation. To determine the importance of D2 synthesis for PSII accumulation in vascular plants and elucidate the contributions of transcriptional and translational regulation, we modified the 5'-untranslated region of psbD via chloroplast transformation in tobacco (Nicotiana tabacum). A drastic reduction in psbD mRNA abundance resulted in a strong decrease in PSII content, impaired photosynthetic electron transport, and retarded growth under autotrophic conditions. Overexpression of the psbD mRNA also increased transcript abundance of psbC (the CP43 inner antenna protein), which is co-transcribed with psbD. Because translation efficiency remained unaltered, translation output of pbsD and psbC increased with mRNA abundance. However, this did not result in increased PSII accumulation. The introduction of point mutations into the Shine-Dalgarno-like sequence or start codon of psbD decreased translation efficiency without causing pronounced effects on PSII accumulation and function. These data show that neither transcription nor translation of psbD and psbC are rate-limiting for PSII biogenesis in vascular plants and that PSII assembly and accumulation in tobacco are controlled by different mechanisms than in cyanobacteria or in C. reinhardtii.
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Affiliation(s)
- Han-Yi Fu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Rabea Ghandour
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Reimo Zoschke
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Mark Aurel Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
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14
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Westrich LD, Gotsmann VL, Herkt C, Ries F, Kazek T, Trösch R, Armbruster L, Mühlenbeck JS, Ramundo S, Nickelsen J, Finkemeier I, Wirtz M, Storchová Z, Räschle M, Willmund F. The versatile interactome of chloroplast ribosomes revealed by affinity purification mass spectrometry. Nucleic Acids Res 2021; 49:400-415. [PMID: 33330923 PMCID: PMC7797057 DOI: 10.1093/nar/gkaa1192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022] Open
Abstract
In plant cells, chloroplast gene expression is predominantly controlled through post-transcriptional regulation. Such fine-tuning is vital for precisely orchestrating protein complex assembly as for the photosynthesis machinery and for quickly responding to environmental changes. While regulation of chloroplast protein synthesis is of central importance, little is known about the degree and nature of the regulatory network, mainly due to challenges associated with the specific isolation of transient ribosome interactors. Here, we established a ribosome affinity purification method, which enabled us to broadly uncover putative ribosome-associated proteins in chloroplasts. Endogenously tagging of a protein of the large or small subunit revealed not only interactors of the holo complex, but also preferential interactors of the two subunits. This includes known canonical regulatory proteins as well as several new proteins belonging to the categories of protein and RNA regulation, photosystem biogenesis, redox control and metabolism. The sensitivity of the here applied screen was validated for various transiently interacting proteins. We further provided evidence for the existence of a ribosome-associated Nα-acetyltransferase in chloroplasts and its ability to acetylate substrate proteins at their N-terminus. The broad set of ribosome interactors underscores the potential to regulate chloroplast gene expression on the level of protein synthesis.
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Affiliation(s)
- Lisa Désirée Westrich
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Vincent Leon Gotsmann
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Claudia Herkt
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Fabian Ries
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Tanja Kazek
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Raphael Trösch
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
| | - Laura Armbruster
- Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany
| | - Jens Stephan Mühlenbeck
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 7, 48149 Münster, Germany
| | - Silvia Ramundo
- Department of Biochemistry and Biophysics, University of California, 600 16th St, N316, San Francisco, CA 94143, USA
| | - Jörg Nickelsen
- Department of Molecular Plant Science, University of Munich, Grosshaderner-Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 7, 48149 Münster, Germany
| | - Markus Wirtz
- Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany
| | - Zuzana Storchová
- Molecular Genetics, University of Kaiserslautern, Paul-Ehrlich-Str. 24, 67663 Kaiserslautern, Germany
| | - Markus Räschle
- Molecular Genetics, University of Kaiserslautern, Paul-Ehrlich-Str. 24, 67663 Kaiserslautern, Germany
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Str. 23, 67663 Kaiserslautern, Germany
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15
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Klasek L, Inoue K, Theg SM. Chloroplast Chaperonin-Mediated Targeting of a Thylakoid Membrane Protein. THE PLANT CELL 2020; 32:3884-3901. [PMID: 33093145 PMCID: PMC7721336 DOI: 10.1105/tpc.20.00309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/11/2020] [Accepted: 10/21/2020] [Indexed: 05/08/2023]
Abstract
Posttranslational protein targeting requires chaperone assistance to direct insertion-competent proteins to integration pathways. Chloroplasts integrate nearly all thylakoid transmembrane proteins posttranslationally, but mechanisms in the stroma that assist their insertion remain largely undefined. Here, we investigated how the chloroplast chaperonin (Cpn60) facilitated the thylakoid integration of Plastidic type I signal peptidase 1 (Plsp1) using in vitro targeting assays. Cpn60 bound Plsp1 in the stroma. In isolated chloroplasts, the membrane integration of imported Plsp1 correlated with its dissociation from Cpn60. When the Plsp1 residues that interacted with Cpn60 were removed, Plsp1 did not integrate into the membrane. These results suggested Cpn60 was an intermediate in thylakoid targeting of Plsp1. In isolated thylakoids, the integration of Plsp1 decreased when Cpn60 was present in excess of cpSecA1, the stromal motor of the cpSec1 translocon that inserts unfolded Plsp1 into the thylakoid. An excess of cpSecA1 favored integration. Introducing Cpn60's obligate substrate RbcL displaced Cpn60-bound Plsp1; then, the released Plsp1 exhibited increased accessibility to cpSec1. These in vitro targeting experiments support a model in which Cpn60 captures and then releases insertion-competent Plsp1, whereas cpSecA1 recognizes free Plsp1 for integration. Thylakoid transmembrane proteins in the stroma can interact with Cpn60 to shield themselves from the aqueous environment.
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Affiliation(s)
- Laura Klasek
- Department of Plant Biology, University of California Davis, Davis, California 95616
| | - Kentaro Inoue
- Department of Plant Sciences, University of California Davis, Davis, California 95616
| | - Steven M Theg
- Department of Plant Biology, University of California Davis, Davis, California 95616
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16
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Kage U, Powell JJ, Gardiner DM, Kazan K. Ribosome profiling in plants: what is not lost in translation? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5323-5332. [PMID: 32459844 DOI: 10.1093/jxb/eraa227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/05/2020] [Indexed: 05/03/2023]
Abstract
Translation is a highly dynamic cellular process whereby genetic information residing in an mRNA molecule is converted into a protein that in turn executes specific functions. However, pre-synthesized mRNA levels do not always correlate with corresponding protein levels, suggesting that translational control plays an essential role in gene regulation. A better understanding of how gene expression is regulated during translation will enable the discovery of new genes and mechanisms that control important traits in plants. Therefore, in recent years, several methods have been developed to analyse the translatome; that is, all mRNAs being actively translated at a given time, tissue, and/or developmental stage. Ribosome profiling or ribo-seq is one such technology revolutionizing our ability to analyse the translatome and in turn understand translational control of gene expression. Ribo-seq involves isolating mRNA-ribosome complexes, treating them with a RNase, and then identifying ribosome-protected mRNA regions by deep sequencing. Here, we briefly review recent ribosome profiling studies that revealed new insights into plant biology. Manipulation of novel genes identified using ribosome profiling could prove useful for increasing yield through improved biotic and abiotic stress tolerance.
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Affiliation(s)
- Udaykumar Kage
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, St Lucia, QLD, Australia
| | - Jonathan J Powell
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, St Lucia, QLD, Australia
| | - Donald M Gardiner
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, St Lucia, QLD, Australia
| | - Kemal Kazan
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, St Lucia, QLD, Australia
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17
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Light-induced psbA translation in plants is triggered by photosystem II damage via an assembly-linked autoregulatory circuit. Proc Natl Acad Sci U S A 2020; 117:21775-21784. [PMID: 32817480 DOI: 10.1073/pnas.2007833117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The D1 reaction center protein of photosystem II (PSII) is subject to light-induced damage. Degradation of damaged D1 and its replacement by nascent D1 are at the heart of a PSII repair cycle, without which photosynthesis is inhibited. In mature plant chloroplasts, light stimulates the recruitment of ribosomes specifically to psbA mRNA to provide nascent D1 for PSII repair and also triggers a global increase in translation elongation rate. The light-induced signals that initiate these responses are unclear. We present action spectrum and genetic data indicating that the light-induced recruitment of ribosomes to psbA mRNA is triggered by D1 photodamage, whereas the global stimulation of translation elongation is triggered by photosynthetic electron transport. Furthermore, mutants lacking HCF136, which mediates an early step in D1 assembly, exhibit constitutively high psbA ribosome occupancy in the dark and differ in this way from mutants lacking PSII for other reasons. These results, together with the recent elucidation of a thylakoid membrane complex that functions in PSII assembly, PSII repair, and psbA translation, suggest an autoregulatory mechanism in which the light-induced degradation of D1 relieves repressive interactions between D1 and translational activators in the complex. We suggest that the presence of D1 in this complex coordinates D1 synthesis with the need for nascent D1 during both PSII biogenesis and PSII repair in plant chloroplasts.
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18
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Recent advances in ribosome profiling for deciphering translational regulation. Methods 2020; 176:46-54. [DOI: 10.1016/j.ymeth.2019.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 05/02/2019] [Accepted: 05/15/2019] [Indexed: 12/16/2022] Open
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19
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Teubner M, Lenzen B, Espenberger LB, Fuss J, Nickelsen J, Krause K, Ruwe H, Schmitz-Linneweber C. The Chloroplast Ribonucleoprotein CP33B Quantitatively Binds the psbA mRNA. PLANTS 2020; 9:plants9030367. [PMID: 32192026 PMCID: PMC7154868 DOI: 10.3390/plants9030367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 01/25/2023]
Abstract
Chloroplast RNAs are stabilized and processed by a multitude of nuclear-encoded RNA-binding proteins, often in response to external stimuli like light and temperature. A particularly interesting RNA-based regulation occurs with the psbA mRNA, which shows light-dependent translation. Recently, the chloroplast ribonucleoprotein CP33B was identified as a ligand of the psbA mRNA. We here characterized the interaction of CP33B with chloroplast RNAs in greater detail using a combination of RIP-chip, quantitative dot-blot, and RNA-Bind-n-Seq experiments. We demonstrate that CP33B prefers psbA over all other chloroplast RNAs and associates with the vast majority of the psbA transcript pool. The RNA sequence target motif, determined in vitro, does not fully explain CP33B's preference for psbA, suggesting that there are other determinants of specificity in vivo.
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Affiliation(s)
- Marlene Teubner
- Institute of Biology, Department of Life Sciences, Humboldt University Berlin, 10115 Berlin, Germany; (M.T.); (B.L.); (L.B.E.); (H.R.)
| | - Benjamin Lenzen
- Institute of Biology, Department of Life Sciences, Humboldt University Berlin, 10115 Berlin, Germany; (M.T.); (B.L.); (L.B.E.); (H.R.)
| | - Lucas Bernal Espenberger
- Institute of Biology, Department of Life Sciences, Humboldt University Berlin, 10115 Berlin, Germany; (M.T.); (B.L.); (L.B.E.); (H.R.)
| | - Janina Fuss
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway; (J.F.); (K.K.)
| | - Jörg Nickelsen
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, 82152 Planegg-Martinsried, Germany;
| | - Kirsten Krause
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway; (J.F.); (K.K.)
| | - Hannes Ruwe
- Institute of Biology, Department of Life Sciences, Humboldt University Berlin, 10115 Berlin, Germany; (M.T.); (B.L.); (L.B.E.); (H.R.)
| | - Christian Schmitz-Linneweber
- Institute of Biology, Department of Life Sciences, Humboldt University Berlin, 10115 Berlin, Germany; (M.T.); (B.L.); (L.B.E.); (H.R.)
- Correspondence: ; Tel.: ++49-30-2093-49700
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20
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Co-Translational Protein Folding and Sorting in Chloroplasts. PLANTS 2020; 9:plants9020214. [PMID: 32045984 PMCID: PMC7076657 DOI: 10.3390/plants9020214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 01/22/2023]
Abstract
Cells depend on the continuous renewal of their proteome composition during the cell cycle and in order to replace aberrant proteins or to react to changing environmental conditions. In higher eukaryotes, protein synthesis is achieved by up to five million ribosomes per cell. With the fast kinetics of translation, the large number of newly made proteins generates a substantial burden for protein homeostasis and requires a highly orchestrated cascade of factors promoting folding, sorting and final maturation. Several of the involved factors directly bind to translating ribosomes for the early processing of emerging nascent polypeptides and the translocation of ribosome nascent chain complexes to target membranes. In plant cells, protein synthesis also occurs in chloroplasts serving the expression of a relatively small set of 60–100 protein-coding genes. However, most of these proteins, together with nucleus-derived subunits, form central complexes majorly involved in the essential processes of photosynthetic light reaction, carbon fixation, metabolism and gene expression. Biogenesis of these heterogenic complexes adds an additional level of complexity for protein biogenesis. In this review, we summarize the current knowledge about co-translationally binding factors in chloroplasts and discuss their role in protein folding and ribosome translocation to thylakoid membranes.
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21
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Exploring the Link between Photosystem II Assembly and Translation of the Chloroplast psbA mRNA. PLANTS 2020; 9:plants9020152. [PMID: 31991763 PMCID: PMC7076361 DOI: 10.3390/plants9020152] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022]
Abstract
Photosystem II (PSII) in chloroplasts and cyanobacteria contains approximately fifteen core proteins, which organize numerous pigments and prosthetic groups that mediate the light-driven water-splitting activity that drives oxygenic photosynthesis. The PSII reaction center protein D1 is subject to photodamage, whose repair requires degradation of damaged D1 and its replacement with nascent D1. Mechanisms that couple D1 synthesis with PSII assembly and repair are poorly understood. We address this question by using ribosome profiling to analyze the translation of chloroplast mRNAs in maize and Arabidopsis mutants with defects in PSII assembly. We found that OHP1, OHP2, and HCF244, which comprise a recently elucidated complex involved in PSII assembly and repair, are each required for the recruitment of ribosomes to psbA mRNA, which encodes D1. By contrast, HCF136, which acts upstream of the OHP1/OHP2/HCF244 complex during PSII assembly, does not have this effect. The fact that the OHP1/OHP2/HCF244 complex brings D1 into proximity with three proteins with dual roles in PSII assembly and psbA ribosome recruitment suggests that this complex is the hub of a translational autoregulatory mechanism that coordinates D1 synthesis with need for nascent D1 during PSII biogenesis and repair.
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22
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Sun Y, Valente-Paterno M, Bakhtiari S, Law C, Zhan Y, Zerges W. Photosystem Biogenesis Is Localized to the Translation Zone in the Chloroplast of Chlamydomonas. THE PLANT CELL 2019; 31:3057-3072. [PMID: 31591163 PMCID: PMC6925001 DOI: 10.1105/tpc.19.00263] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/18/2019] [Accepted: 10/07/2019] [Indexed: 05/04/2023]
Abstract
Intracellular processes can be localized for efficiency or regulation. For example, localized mRNA translation by chloroplastic ribosomes occurs in the biogenesis of PSII, one of the two photosystems of the photosynthetic electron transport chain in the chloroplasts of plants and algae. The biogenesis of PSI and PSII requires the synthesis and assembly of their constituent polypeptide subunits, pigments, and cofactors. Although these biosynthetic pathways are well characterized, less is known about when and where they occur in developing chloroplasts. Here, we used fluorescence microscopy in the unicellular alga Chlamydomonas reinhardtii to reveal spatiotemporal organization in photosystem biogenesis. We focused on translation by chloroplastic ribosomes and chlorophyll biosynthesis in two developmental contexts of active photosystem biogenesis: (1) growth of the mature chloroplast and (2) greening of a nonphotosynthetic chloroplast. The results reveal that a translation zone is the primary location of the biogenesis of PSI and PSII. This discretely localized region within the chloroplast contrasts with the distributions of photosystems throughout this organelle and, therefore, is likely a hub where anabolic pathways converge for photosystem biogenesis.plantcell;31/12/3057/FX1F1fx1.
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Affiliation(s)
- Yi Sun
- Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Melissa Valente-Paterno
- Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Shiva Bakhtiari
- Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Christopher Law
- Centre for Microscopy and Cellular Imaging, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Yu Zhan
- Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - William Zerges
- Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada
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23
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Hristou A, Gerlach I, Stolle DS, Neumann J, Bischoff A, Dünschede B, Nowaczyk MM, Zoschke R, Schünemann D. Ribosome-Associated Chloroplast SRP54 Enables Efficient Cotranslational Membrane Insertion of Key Photosynthetic Proteins. THE PLANT CELL 2019; 31:2734-2750. [PMID: 31444312 PMCID: PMC6881123 DOI: 10.1105/tpc.19.00169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/12/2019] [Accepted: 08/22/2019] [Indexed: 05/20/2023]
Abstract
Key proteins of the photosynthetic complexes are encoded in the chloroplast genome and cotranslationally inserted into the thylakoid membrane. However, the molecular details of this process are largely unknown. Here, we demonstrate by ribosome profiling that the conserved chloroplast signal recognition particle subunit (cpSRP54) is required for efficient cotranslational targeting of several central photosynthetic proteins, such as the PSII PsbA (D1) subunit, in Arabidopsis (Arabidopsis thaliana). High-resolution analysis of membrane-associated and soluble ribosome footprints revealed that the SRP-dependent membrane targeting of PsbA is already initiated at an early translation step before exposure of the nascent chain from the ribosome. In contrast to cytosolic SRP, which contacts the ribosome close to the peptide tunnel exit site, analysis of the cpSRP54/ribosome binding interface revealed a direct interaction of cpSRP54 and the ribosomal subunit uL4, which is not located at the tunnel exit site but forms a part of the internal peptide tunnel wall by a loop domain. The plastid-specific C-terminal tail region of cpSRP54 plays a crucial role in uL4 binding. Our data indicate a novel mechanism of SRP-dependent membrane protein transport with the cpSRP54/uL4 interaction as a central element in early initiation of cotranslational membrane targeting.
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Affiliation(s)
- Athina Hristou
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Ines Gerlach
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Dominique S Stolle
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Jennifer Neumann
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Annika Bischoff
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Beatrix Dünschede
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Danja Schünemann
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
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24
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Fujita T, Kurihara Y, Iwasaki S. The Plant Translatome Surveyed by Ribosome Profiling. PLANT & CELL PHYSIOLOGY 2019; 60:1917-1926. [PMID: 31004488 DOI: 10.1093/pcp/pcz059] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/31/2019] [Indexed: 06/09/2023]
Abstract
Although transcriptome changes have long been recognized as a mechanism to induce tentative substitution of expressed genes in diverse biological processes in plants, the regulation of translation-the final step of the central dogma of molecular biology-emerged as an alternative and prominent layer in defining the output of genes. Despite these demands, the genome-wide analysis of protein synthesis has posed technical challenges, resulting in the plant translatome being poorly understood. The development of ribosome profiling promises to address the hidden aspects of translation, and its application to plants is revolutionizing our knowledge of the translatome. This review outlines the array of recent findings provided by ribosome profiling and illustrates the power of the versatile technique in green organisms.
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Affiliation(s)
- Tomoya Fujita
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Yukio Kurihara
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
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25
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Fernandez DE. Two paths diverged in the stroma: targeting to dual SEC translocase systems in chloroplasts. PHOTOSYNTHESIS RESEARCH 2018; 138:277-287. [PMID: 29951837 DOI: 10.1007/s11120-018-0541-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
Chloroplasts inherited systems and strategies for protein targeting, translocation, and integration from their cyanobacterial ancestor. Unlike cyanobacteria however, chloroplasts in green algae and plants contain two distinct SEC translocase/integrase systems: the SEC1 system in the thylakoid membrane and the SEC2 system in the inner envelope membrane. This review summarizes the mode of action of SEC translocases, identification of components of the SEC2 system, evolutionary history of SCY and SECA genes, and previous work on the co- and post-translational targeting of lumenal and thylakoid membrane proteins to the SEC1 system. Recent work identifying substrates for the SEC2 system and potential features that may contribute to inner envelope targeting are also discussed.
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Affiliation(s)
- Donna E Fernandez
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI, 53706, USA.
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26
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Albanese P, Manfredi M, Re A, Marengo E, Saracco G, Pagliano C. Thylakoid proteome modulation in pea plants grown at different irradiances: quantitative proteomic profiling in a non-model organism aided by transcriptomic data integration. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:786-800. [PMID: 30118564 DOI: 10.1111/tpj.14068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/03/2018] [Accepted: 08/13/2018] [Indexed: 05/02/2023]
Abstract
Plant thylakoid membranes contain hundreds of proteins that closely interact to cope with ever-changing environmental conditions. We investigated how Pisum sativum L. (pea) grown at different irradiances optimizes light-use efficiency through the differential accumulation of thylakoid proteins. Thylakoid membranes from plants grown under low (LL), moderate (ML) and high (HL) light intensity were characterized by combining chlorophyll fluorescence measurements with quantitative label-free proteomic analysis. Protein sequences retrieved from available transcriptomic data considerably improved thylakoid proteome profiling, increasing the quantifiable proteins from 63 to 194. The experimental approach used also demonstrates that this integrative omics strategy is powerful for unravelling protein isoforms and functions that are still unknown in non-model organisms. We found that the different growth irradiances affect the electron transport kinetics but not the relative abundance of photosystems (PS) I and II. Two acclimation strategies were evident. The behaviour of plants acclimated to LL was compared at higher irradiances: (i) in ML, plants turn on photoprotective responses mostly modulating the PSII light-harvesting capacity, either accumulating Lhcb4.3 or favouring the xanthophyll cycle; (ii) in HL, plants reduce the pool of light-harvesting complex II and enhance the PSII repair cycle. When growing at ML and HL, plants accumulate ATP synthase, boosting both cyclic and linear electron transport by finely tuning the ΔpH across the membrane and optimizing protein trafficking by adjusting the thylakoid architecture. Our results provide a quantitative snapshot of how plants coordinate light harvesting, electron transport and protein synthesis by adjusting the thylakoid membrane proteome in a light-dependent manner.
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Affiliation(s)
- Pascal Albanese
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Environment Park, Via Livorno 60, 10144, Torino, Italy
| | - Marcello Manfredi
- ISALIT-Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121, Alessandria, Italy
- Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121, Alessandria, Italy
| | - Angela Re
- Center for Sustainable Future Technologies-CSFT@POLITO, Istituto Italiano di Tecnologia, Corso Trento 21, 10129, Torino, Italy
| | - Emilio Marengo
- Department of Science and Technological Innovation, University of Eastern Piedmont, Viale T. Michel 11, 15121, Alessandria, Italy
| | - Guido Saracco
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Environment Park, Via Livorno 60, 10144, Torino, Italy
| | - Cristina Pagliano
- Applied Science and Technology Department-BioSolar Lab, Politecnico di Torino, Environment Park, Via Livorno 60, 10144, Torino, Italy
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27
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Macedo-Osorio KS, Pérez-España VH, Garibay-Orijel C, Guzmán-Zapata D, Durán-Figueroa NV, Badillo-Corona JA. Intercistronic expression elements (IEE) from the chloroplast of Chlamydomonas reinhardtii can be used for the expression of foreign genes in synthetic operons. PLANT MOLECULAR BIOLOGY 2018; 98:303-317. [PMID: 30225747 DOI: 10.1007/s11103-018-0776-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/31/2018] [Indexed: 05/21/2023]
Abstract
Two intercistronic regions were identified as functional intercistronic expression elements (IEE) for the simultaneous expression of aphA-6 and gfp in a synthetic operon in the chloroplast of C. reinhardtii. Chlamydomonas reinhardtii, a biflagellate photosynthetic microalga, has been widely used in basic and applied science. Already three decades ago, Chlamydomonas had its chloroplast genome transformed and to this day constitutes the only alga routinely used in transplastomic technology. Despite the fact that over a 100 foreign genes have been expressed from the chloroplast genome, little has been done to address the challenge of expressing multiple genes in the form of operons, a development that is needed and crucial to push forward metabolic engineering and synthetic biology in this organism. Here, we studied five intercistronic regions and investigated if they can be used as intercistronic expression elements (IEE) in synthetic operons to drive the expression of foreign genes in the chloroplast of C. reinhardtii. The intercistronic regions were those from the psbB-psbT, psbN-psbH, psaC-petL, petL-trnN and tscA-chlN chloroplast operons, and the foreign genes were the aminoglycoside 3'-phosphotransferase (aphA-6), which confers resistance to kanamycin, and the green fluorescent protein gene (gfp). While all the intercistronic regions yielded lines that were resistant to kanamycin, only two (obtained with intercistronic regions from psbN-psbH and tscA-chlN) were identified as functional IEEs, yielding lines in which the second cistron (gfp) was translated and generated GFP. The IEEs we have identified could be useful for the stacking of genes for metabolic engineering or synthetic biology circuits in the chloroplast of C. reinhardtii.
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Affiliation(s)
- Karla S Macedo-Osorio
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Av. Acueducto SN, Col. Barrio la Laguna Ticoman, Mexico City, Mexico
| | - Víctor H Pérez-España
- Universidad Autónoma del Estado de Hidalgo, Escuela Superior de Apan, Carretera Apan Calpulalpan km 8, Col. Chimalpa-Tlalayote, Apan, Hidalgo, Mexico
| | - Claudio Garibay-Orijel
- Labcitec, Camino a Atzacoalco 99, Col. Constitución de la República, Mexico City, Mexico
| | - Daniel Guzmán-Zapata
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Av. Acueducto SN, Col. Barrio la Laguna Ticoman, Mexico City, Mexico
| | - Noé V Durán-Figueroa
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Av. Acueducto SN, Col. Barrio la Laguna Ticoman, Mexico City, Mexico
| | - Jesús A Badillo-Corona
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Av. Acueducto SN, Col. Barrio la Laguna Ticoman, Mexico City, Mexico.
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28
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Trösch R, Barahimipour R, Gao Y, Badillo-Corona JA, Gotsmann VL, Zimmer D, Mühlhaus T, Zoschke R, Willmund F. Commonalities and differences of chloroplast translation in a green alga and land plants. NATURE PLANTS 2018; 4:564-575. [PMID: 30061751 DOI: 10.1038/s41477-018-0211-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/02/2018] [Indexed: 06/08/2023]
Abstract
Chloroplast gene expression is a fascinating and highly regulated process, which was mainly studied on specific genes in a few model organisms including the unicellular green alga Chlamydomonas (Chlamydomonas reinhardtii) and the embryophyte (land) plants tobacco (Nicotiana tabacum) and Arabidopsis (Arabidopsis thaliana). However, a direct plastid genome-wide interspecies comparison of chloroplast gene expression that includes translation was missing. We adapted a targeted chloroplast ribosome profiling approach to quantitatively compare RNA abundance and translation output between Chlamydomonas, tobacco and Arabidopsis. The re-analysis of established chloroplast mutants confirmed the capability of the approach by detecting known as well as previously undetected translation defects (including the potential photosystem II assembly-dependent regulation of PsbH). Systematic comparison of the algal and land plant wild-type gene expression showed that, for most genes, the steady-state translation output is highly conserved among the three species, while the levels of transcript accumulation are more distinct. Whereas in Chlamydomonas transcript accumulation and translation output are closely balanced, this correlation is less obvious in embryophytes, indicating more pronounced translational regulation. Altogether, this suggests that green algae and land plants evolved different strategies to achieve conserved levels of protein synthesis.
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Affiliation(s)
- Raphael Trösch
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Yang Gao
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Vincent Leon Gotsmann
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Kaiserslautern, Germany
| | - David Zimmer
- Computational Systems Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Kaiserslautern, Germany.
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29
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Perez Boerema A, Aibara S, Paul B, Tobiasson V, Kimanius D, Forsberg BO, Wallden K, Lindahl E, Amunts A. Structure of the chloroplast ribosome with chl-RRF and hibernation-promoting factor. NATURE PLANTS 2018; 4:212-217. [PMID: 29610536 DOI: 10.1038/s41477-018-0129-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 03/05/2018] [Indexed: 06/08/2023]
Abstract
Oxygenic photosynthesis produces oxygen and builds a variety of organic compounds, changing the chemistry of the air, the sea and fuelling the food chain on our planet. The photochemical reactions underpinning this process in plants take place in the chloroplast. Chloroplasts evolved ~1.2 billion years ago from an engulfed primordial diazotrophic cyanobacterium, and chlororibosomes are responsible for synthesis of the core proteins driving photochemical reactions. Chlororibosomal activity is spatiotemporally coupled to the synthesis and incorporation of functionally essential co-factors, implying the presence of chloroplast-specific regulatory mechanisms and structural adaptation of the chlororibosome1,2. Despite recent structural information3-6, some of these aspects remained elusive. To provide new insights into the structural specialities and evolution, we report a comprehensive analysis of the 2.9-3.1 Å resolution electron cryo-microscopy structure of the spinach chlororibosome in complex with its recycling factor and hibernation-promoting factor. The model reveals a prominent channel extending from the exit tunnel to the chlororibosome exterior, structural re-arrangements that lead to increased surface area for translocon binding, and experimental evidence for parallel and convergent evolution of chloro- and mitoribosomes.
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Affiliation(s)
- Annemarie Perez Boerema
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Shintaro Aibara
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Bijoya Paul
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Dari Kimanius
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Björn O Forsberg
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Karin Wallden
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Erik Lindahl
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - A Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
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30
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Zoschke R, Bock R. Chloroplast Translation: Structural and Functional Organization, Operational Control, and Regulation. THE PLANT CELL 2018; 30:745-770. [PMID: 29610211 PMCID: PMC5969280 DOI: 10.1105/tpc.18.00016] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 05/20/2023]
Abstract
Chloroplast translation is essential for cellular viability and plant development. Its positioning at the intersection of organellar RNA and protein metabolism makes it a unique point for the regulation of gene expression in response to internal and external cues. Recently obtained high-resolution structures of plastid ribosomes, the development of approaches allowing genome-wide analyses of chloroplast translation (i.e., ribosome profiling), and the discovery of RNA binding proteins involved in the control of translational activity have greatly increased our understanding of the chloroplast translation process and its regulation. In this review, we provide an overview of the current knowledge of the chloroplast translation machinery, its structure, organization, and function. In addition, we summarize the techniques that are currently available to study chloroplast translation and describe how translational activity is controlled and which cis-elements and trans-factors are involved. Finally, we discuss how translational control contributes to the regulation of chloroplast gene expression in response to developmental, environmental, and physiological cues. We also illustrate the commonalities and the differences between the chloroplast and bacterial translation machineries and the mechanisms of protein biosynthesis in these two prokaryotic systems.
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Affiliation(s)
- Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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31
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Allen JF. Translating photosynthesis. NATURE PLANTS 2018; 4:199-200. [PMID: 29610533 DOI: 10.1038/s41477-018-0132-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- John F Allen
- Research Department of Genetics, Evolution and Environment, University College London, London, UK.
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32
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Legen J, Ruf S, Kroop X, Wang G, Barkan A, Bock R, Schmitz-Linneweber C. Stabilization and translation of synthetic operon-derived mRNAs in chloroplasts by sequences representing PPR protein-binding sites. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:8-21. [PMID: 29418028 DOI: 10.1111/tpj.13863] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 12/28/2017] [Accepted: 01/17/2018] [Indexed: 05/08/2023]
Abstract
The chloroplast is a prime target for genetic engineering in plants, offering various advantages over nuclear transformation. For example, chloroplasts allow the expression of polycistronic transcripts and thus to engineer complex metabolic pathways. Each cistron within such a longer transcript needs its own expression elements. Within the 5'-UTR, such expression elements are needed for stabilizing mRNAs and for translation of the downstream reading frame. One of the few effective expression elements used so far in transplastomic approaches is the intercistronic expression element (IEE). The IEE is derived from the psbT-psbH intergenic region and includes a target sequence of the RNA binding protein HCF107. We here show that excessive expression of the IEE can lead to specific defects of endogenous chloroplast mRNA stabilization, likely via depletion of HCF107. Key players in chloroplast transcript stabilization and translation are pentatricopeptide repeat (PPR) proteins, which are structurally related to HCF107. PPR proteins that stabilize mRNAs leave behind short RNA footprints that are indicators of their activity. We identified such sRNAs in tobacco, and demonstrate that they are sufficient to stabilize and stimulate translation of mRNAs from synthetic dicistronic transgenes in chloroplasts. Thus, minimal sequence elements are generally adequate to support key steps in chloroplast gene expression, i.e. RNA stability and translation. Furthermore, our analysis expands the repertoire of available expression elements to facilitate the assembly and expression of multi-gene ensembles in the chloroplast.
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Affiliation(s)
- Julia Legen
- Institut für Biologie, Humboldt-Universität Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, Berlin, 10115, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP), Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Xenia Kroop
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP), Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Gongwei Wang
- Institut für Biologie, Humboldt-Universität Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, Berlin, 10115, Germany
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP), Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
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33
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McCormick S. Binding sites for pentatricopeptide repeat proteins differentially activate chloroplast transgenes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:6-7. [PMID: 29575498 DOI: 10.1111/tpj.13886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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34
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Gawroński P, Jensen PE, Karpiński S, Leister D, Scharff LB. Pausing of Chloroplast Ribosomes Is Induced by Multiple Features and Is Linked to the Assembly of Photosynthetic Complexes. PLANT PHYSIOLOGY 2018; 176:2557-2569. [PMID: 29298822 PMCID: PMC5841727 DOI: 10.1104/pp.17.01564] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/02/2018] [Indexed: 05/11/2023]
Abstract
Many mRNAs contain pause sites that briefly interrupt the progress of translation. Specific features that induce ribosome pausing have been described; however, their individual contributions to pause-site formation, and the overall biological significance of ribosome pausing, remain largely unclear. We have taken advantage of the compact genome of chloroplasts to carry out a plastid genome-wide survey of pause sites, as a basis for studying the impact of pausing on posttranslational processes. Based on ribosomal profiling of Arabidopsis (Arabidopsis thaliana) chloroplast mRNAs, we demonstrate that a combination of factors-mRNA secondary structure, internal Shine-Dalgarno sequences, and positively charged amino acids in the nascent peptide chain-explains 95% of the major pause sites on plastid mRNAs, whereas codon usage has little impact. The distribution of the pause sites is nonrandom and conforms to distinct patterns in the vicinity of sequences coding for transmembrane domains, which depend on their orientation within the membrane as well as being next to sequences coding for cofactor binding sites. We found strong indications that the mechanisms causing ribosomal pausing and at least some of the ribosomes pause sites are conserved between distantly related plant species. In addition, the positions of features that cause pausing are well conserved in photoautotrophic plants, but less so in their nonphotosynthetic, parasitic relatives, implying that the synthesis and assembly of photosynthetic multiprotein complexes requires localized ribosome pausing.
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Affiliation(s)
- Piotr Gawroński
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
- Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland
| | - Poul Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Stanisław Karpiński
- Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland
- Plant Breeding and Acclimatization Institute, National Research Institute, Radzików, 05-870 Błonie, Poland
| | - Dario Leister
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
- Plant Molecular Biology, Department Biology I, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Lars B Scharff
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
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Abstract
The plastids, including chloroplasts, are a group of interrelated organelles that confer photoautotrophic growth and the unique metabolic capabilities that are characteristic of plant systems. Plastid biogenesis relies on the expression, import, and assembly of thousands of nuclear encoded preproteins. Plastid proteomes undergo rapid remodeling in response to developmental and environmental signals to generate functionally distinct plastid types in specific cells and tissues. In this review, we will highlight the central role of the plastid protein import system in regulating and coordinating the import of functionally related sets of preproteins that are required for plastid-type transitions and maintenance.
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Króliczewski J, Bartoszewski R, Króliczewska B. Chloroplast PetD protein: evidence for SRP/Alb3-dependent insertion into the thylakoid membrane. BMC PLANT BIOLOGY 2017; 17:213. [PMID: 29162052 PMCID: PMC5697057 DOI: 10.1186/s12870-017-1176-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/13/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND In thylakoid membrane, each monomer of the dimeric complex of cytochrome b 6 f is comprised of eight subunits that are both nucleus- and plastid-encoded. Proper cytochrome b 6 f complex integration into the thylakoid membrane requires numerous regulatory factors for coordinated transport, insertion and assembly of the subunits. Although, the chloroplast-encoded cytochrome b 6 f subunit IV (PetD) consists of three transmembrane helices, the signal and the mechanism of protein integration into the thylakoid membrane have not been identified. RESULTS Here, we demonstrate that the native PetD subunit cannot incorporate into the thylakoid membranes spontaneously, but that proper integration occurs through the post-translational signal recognition particle (SRP) pathway. Furthermore, we show that PetD insertion into thylakoid membrane involves the coordinated action of cpFTSY, cpSRP54 and ALB3 insertase. CONCLUSIONS PetD subunit integration into the thylakoid membrane is a post-translational and an SRP-dependent process that requires the formation of the cpSRP-cpFtsY-ALB3-PetD complex. This data provides a new insight into the molecular mechanisms by which membrane proteins integration into the thylakoid membrane is accomplished and is not limited to PetD.
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Affiliation(s)
- Jarosław Króliczewski
- Faculty of Biotechnology, University of Wrocław, Fryderyka Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Rafał Bartoszewski
- Department of Biology and Pharmaceutical Botany Medical University of Gdańsk, Hallera 107, 80-416 Gdansk, Poland
| | - Bożena Króliczewska
- Department of Animal Physiology and Biostructure, Faculty of Veterinary Medicine Wroclaw University of Environmental and Life Sciences, C.K Norwida 31, 50-375 Wrocław, Poland
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Hsu PY, Benfey PN. Small but Mighty: Functional Peptides Encoded by Small ORFs in Plants. Proteomics 2017; 18:e1700038. [PMID: 28759167 DOI: 10.1002/pmic.201700038] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/26/2017] [Indexed: 12/18/2022]
Abstract
Peptides encoded by small open reading frames (sORFs, usually <100 codons) play critical regulatory roles in plant development and environmental responses. Despite their importance, only a small number of these peptides have been identified and characterized. Genomic studies have revealed that many plant genomes contain thousands of possible sORFs, which could potentially encode small peptides. The challenge is to distinguish translated sORFs from nontranslated ones. Here, we highlight advances in methodologies for identifying these hidden sORFs in plant genomes, including ribosome profiling and proteomics. We also examine the evidence for new peptides arising from sORFs and discuss their functions in plant development, environmental responses, and translational control.
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Affiliation(s)
| | - Philip N Benfey
- Department of Biology, Duke University, Durham, NC, USA.,Howard Hughes Medical Institute, Duke University, Durham, NC, USA
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38
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Wang S, Yang CI, Shan SO. SecA mediates cotranslational targeting and translocation of an inner membrane protein. J Cell Biol 2017; 216:3639-3653. [PMID: 28928132 PMCID: PMC5674894 DOI: 10.1083/jcb.201704036] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/17/2017] [Accepted: 08/02/2017] [Indexed: 12/02/2022] Open
Abstract
Proteins are thought to be delivered to the bacterial plasma membrane cotranslationally by signal recognition particle or posttranslationally by SecA. Wang et al. identify a new membrane protein–targeting pathway in bacteria in which SecA cotranslationally recognizes and targets the inner membrane protein RodZ, which harbors an internal transmembrane domain. Protein targeting to the bacterial plasma membrane was generally thought to occur via two major pathways: cotranslational targeting by signal recognition particle (SRP) and posttranslational targeting by SecA and SecB. Recently, SecA was found to also bind ribosomes near the nascent polypeptide exit tunnel, but the function of this SecA–ribosome contact remains unclear. In this study, we show that SecA cotranslationally recognizes the nascent chain of an inner membrane protein, RodZ, with high affinity and specificity. In vitro reconstitution and in vivo targeting assays show that SecA is necessary and sufficient to direct the targeting and translocation of RodZ to the bacterial plasma membrane in an obligatorily cotranslational mechanism. Sequence elements upstream and downstream of the RodZ transmembrane domain dictate nascent polypeptide selection by SecA instead of the SRP machinery. These findings identify a new route for the targeting of inner membrane proteins in bacteria and highlight the diversity of targeting pathways that enables an organism to accommodate diverse nascent proteins.
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Affiliation(s)
- Shuai Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Chien-I Yang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
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39
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Stable Membrane-Association of mRNAs in Etiolated, Greening and Mature Plastids. Int J Mol Sci 2017; 18:ijms18091881. [PMID: 28858216 PMCID: PMC5618530 DOI: 10.3390/ijms18091881] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 12/24/2022] Open
Abstract
Chloroplast genes are transcribed as polycistronic precursor RNAs that give rise to a multitude of processing products down to monocistronic forms. Translation of these mRNAs is realized by bacterial type 70S ribosomes. A larger fraction of these ribosomes is attached to chloroplast membranes. This study analyzed transcriptome-wide distribution of plastid mRNAs between soluble and membrane fractions of purified plastids using microarray analyses and validating RNA gel blot hybridizations. To determine the impact of light on mRNA localization, we used etioplasts, greening plastids and mature chloroplasts from Zea mays as a source for membrane and soluble extracts. The results show that the three plastid types display an almost identical distribution of RNAs between the two organellar fractions, which is confirmed by quantitative RNA gel blot analyses. Furthermore, they reveal that different RNAs processed from polycistronic precursors show transcript-autonomous distribution between stroma and membrane fractions. Disruption of ribosomes leads to release of mRNAs from membranes, demonstrating that attachment is likely a direct consequence of translation. We conclude that plastid mRNA distribution is a stable feature of different plastid types, setting up rapid chloroplast translation in any plastid type.
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40
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Schönberg A, Rödiger A, Mehwald W, Galonska J, Christ G, Helm S, Thieme D, Majovsky P, Hoehenwarter W, Baginsky S. Identification of STN7/STN8 kinase targets reveals connections between electron transport, metabolism and gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:1176-1186. [PMID: 28295753 DOI: 10.1111/tpj.13536] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 05/18/2023]
Abstract
The thylakoid-associated kinases STN7 and STN8 are involved in short- and long-term acclimation of photosynthetic electron transport to changing light conditions. Here we report the identification of STN7/STN8 in vivo targets that connect photosynthetic electron transport with metabolism and gene expression. Comparative phosphoproteomics with the stn7 and stn8 single and double mutants identified two proteases, one RNA-binding protein, a ribosomal protein, the large subunit of Rubisco and a ferredoxin-NADP reductase as targets for the thylakoid-associated kinases. Phosphorylation of three of the above proteins can be partially complemented by STN8 in the stn7 single mutant, albeit at lower efficiency, while phosphorylation of the remaining three proteins strictly depends on STN7. The properties of the STN7-dependent phosphorylation site are similar to those of phosphorylated light-harvesting complex proteins entailing glycine or another small hydrophobic amino acid in the -1 position. Our analysis uncovers the STN7/STN8 kinases as mediators between photosynthetic electron transport, its immediate downstream sinks and long-term adaptation processes affecting metabolite accumulation and gene expression.
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Affiliation(s)
- Anna Schönberg
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Anja Rödiger
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Wiebke Mehwald
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Johann Galonska
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Gideon Christ
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Stefan Helm
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Domenika Thieme
- Proteomeanalytik, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany
| | - Petra Majovsky
- Proteomeanalytik, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany
| | | | - Sacha Baginsky
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany
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41
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Zoschke R, Chotewutmontri P, Barkan A. Translation and Co-translational Membrane Engagement of Plastid-encoded Chlorophyll-binding Proteins Are Not Influenced by Chlorophyll Availability in Maize. FRONTIERS IN PLANT SCIENCE 2017; 8:385. [PMID: 28400776 PMCID: PMC5368244 DOI: 10.3389/fpls.2017.00385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/07/2017] [Indexed: 05/11/2023]
Abstract
Chlorophyll is an indispensable constituent of the photosynthetic machinery in green organisms. Bound by apoproteins of photosystems I and II, chlorophyll performs light-harvesting and charge separation. Due to the phototoxic nature of free chlorophyll and its precursors, chlorophyll synthesis is regulated to comply with the availability of nascent chlorophyll-binding apoproteins. Conversely, the synthesis and co-translational insertion of such proteins into the thylakoid membrane have been suggested to be influenced by chlorophyll availability. In this study, we addressed these hypotheses by using ribosome profiling to examine the synthesis and membrane targeting of chlorophyll-binding apoproteins in chlorophyll-deficient chlH maize mutants (Zm-chlH). ChlH encodes the H subunit of the magnesium chelatase (also known as GUN5), which catalyzes the first committed step in chlorophyll synthesis. Our results show that the number and distribution of ribosomes on plastid mRNAs encoding chlorophyll-binding apoproteins are not substantially altered in Zm-chlH mutants, suggesting that chlorophyll has no impact on ribosome dynamics. Additionally, a Zm-chlH mutation does not change the amino acid position at which nascent chlorophyll-binding apoproteins engage the thylakoid membrane, nor the efficiency with which membrane-engagement occurs. Together, these results provide evidence that chlorophyll availability does not selectively activate the translation of plastid mRNAs encoding chlorophyll apoproteins. Our results imply that co- or post-translational proteolysis of apoproteins is the primary mechanism that adjusts apoprotein abundance to chlorophyll availability in plants.
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Affiliation(s)
- Reimo Zoschke
- Max Planck Institute of Molecular Plant PhysiologyPotsdam, Germany
- *Correspondence: Reimo Zoschke,
| | | | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, EugeneOR, USA
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42
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Daniell H, Chan HT, Pasoreck EK. Vaccination via Chloroplast Genetics: Affordable Protein Drugs for the Prevention and Treatment of Inherited or Infectious Human Diseases. Annu Rev Genet 2016; 50:595-618. [PMID: 27893966 PMCID: PMC5496655 DOI: 10.1146/annurev-genet-120215-035349] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Plastid-made biopharmaceuticals treat major metabolic or genetic disorders, including Alzheimer's, diabetes, hypertension, hemophilia, and retinopathy. Booster vaccines made in chloroplasts prevent global infectious diseases, such as tuberculosis, malaria, cholera, and polio, and biological threats, such as anthrax and plague. Recent advances in this field include commercial-scale production of human therapeutic proteins in FDA-approved cGMP facilities, development of tags to deliver protein drugs to targeted human cells or tissues, methods to deliver precise doses, and long-term stability of protein drugs at ambient temperature, maintaining their efficacy. Codon optimization utilizing valuable information from sequenced chloroplast genomes enhanced expression of eukaryotic human or viral genes in chloroplasts and offered unique insights into translation in chloroplasts. Support from major biopharmaceutical companies, development of hydroponic production systems, and evaluation by regulatory agencies, including the CDC, FDA, and USDA, augur well for advancing this novel concept to the clinic and revolutionizing affordable healthcare.
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Affiliation(s)
- Henry Daniell
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
| | - Hui-Ting Chan
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
| | - Elise K Pasoreck
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
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43
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Króliczewski J, Piskozub M, Bartoszewski R, Króliczewska B. ALB3 Insertase Mediates Cytochrome b 6 Co-translational Import into the Thylakoid Membrane. Sci Rep 2016; 6:34557. [PMID: 27698412 PMCID: PMC5048292 DOI: 10.1038/srep34557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/15/2016] [Indexed: 01/10/2023] Open
Abstract
The cytochrome b6 f complex occupies an electrochemically central position in the electron-transport chain bridging the photosynthetic reaction center of PS I and PS II. In plants, the subunits of these thylakoid membrane protein complexes are both chloroplast and nuclear encoded. How the chloroplast-encoded subunits of multi-spanning cytochrome b6 are targeted and inserted into the thylakoid membrane is not fully understood. Experimental approaches to evaluate the cytochrome b6 import mechanism in vivo have been limited to bacterial membranes and were not a part of the chloroplast environment. To evaluate the mechanism governing cytochrome b6 integration in vivo, we performed a comparative analysis of both native and synthetic cytochrome b6 insertion into purified thylakoids. Using biophysical and biochemical methods, we show that cytochrome b6 insertion into the thylakoid membrane is a non-spontaneous co-translational process that involves ALB3 insertase. Furthermore, we provided evidence that CSP41 (chloroplast stem-loop-binding protein of 41 kDa) interacts with RNC-cytochrome b6 complexes, and may be involved in cytochrome b6 (petB) transcript stabilization or processing.
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Affiliation(s)
- Jarosław Króliczewski
- Laboratory of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław Poland
| | - Małgorzata Piskozub
- Amplicon Sp. z o. o., Wrocław, Poland
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Rafał Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Bożena Króliczewska
- Department of Animal Physiology and Biostructure, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
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44
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Kwon KC, Chan HT, León IR, Williams-Carrier R, Barkan A, Daniell H. Codon Optimization to Enhance Expression Yields Insights into Chloroplast Translation. PLANT PHYSIOLOGY 2016; 172:62-77. [PMID: 27465114 PMCID: PMC5074611 DOI: 10.1104/pp.16.00981] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 07/25/2016] [Indexed: 05/20/2023]
Abstract
Codon optimization based on psbA genes from 133 plant species eliminated 105 (human clotting factor VIII heavy chain [FVIII HC]) and 59 (polio VIRAL CAPSID PROTEIN1 [VP1]) rare codons; replacement with only the most highly preferred codons decreased transgene expression (77- to 111-fold) when compared with the codon usage hierarchy of the psbA genes. Targeted proteomic quantification by parallel reaction monitoring analysis showed 4.9- to 7.1-fold or 22.5- to 28.1-fold increase in FVIII or VP1 codon-optimized genes when normalized with stable isotope-labeled standard peptides (or housekeeping protein peptides), but quantitation using western blots showed 6.3- to 8-fold or 91- to 125-fold increase of transgene expression from the same batch of materials, due to limitations in quantitative protein transfer, denaturation, solubility, or stability. Parallel reaction monitoring, to our knowledge validated here for the first time for in planta quantitation of biopharmaceuticals, is especially useful for insoluble or multimeric proteins required for oral drug delivery. Northern blots confirmed that the increase of codon-optimized protein synthesis is at the translational level rather than any impact on transcript abundance. Ribosome footprints did not increase proportionately with VP1 translation or even decreased after FVIII codon optimization but is useful in diagnosing additional rate-limiting steps. A major ribosome pause at CTC leucine codons in the native gene of FVIII HC was eliminated upon codon optimization. Ribosome stalls observed at clusters of serine codons in the codon-optimized VP1 gene provide an opportunity for further optimization. In addition to increasing our understanding of chloroplast translation, these new tools should help to advance this concept toward human clinical studies.
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Affiliation(s)
- Kwang-Chul Kwon
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
| | - Hui-Ting Chan
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
| | - Ileana R León
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
| | - Rosalind Williams-Carrier
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
| | - Alice Barkan
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
| | - Henry Daniell
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030 (K.-C.K., H.-T.C., H.D.);Global Research, Novo Nordisk, Malov DK-2760, Denmark (I.R.L.); andInstitute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229 (R.W.-C., A.B.)
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45
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Chotewutmontri P, Barkan A. Dynamics of Chloroplast Translation during Chloroplast Differentiation in Maize. PLoS Genet 2016; 12:e1006106. [PMID: 27414025 PMCID: PMC4945096 DOI: 10.1371/journal.pgen.1006106] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/13/2016] [Indexed: 11/18/2022] Open
Abstract
Chloroplast genomes in land plants contain approximately 100 genes, the majority of which reside in polycistronic transcription units derived from cyanobacterial operons. The expression of chloroplast genes is integrated into developmental programs underlying the differentiation of photosynthetic cells from non-photosynthetic progenitors. In C4 plants, the partitioning of photosynthesis between two cell types, bundle sheath and mesophyll, adds an additional layer of complexity. We used ribosome profiling and RNA-seq to generate a comprehensive description of chloroplast gene expression at four stages of chloroplast differentiation, as displayed along the maize seedling leaf blade. The rate of protein output of most genes increases early in development and declines once the photosynthetic apparatus is mature. The developmental dynamics of protein output fall into several patterns. Programmed changes in mRNA abundance make a strong contribution to the developmental shifts in protein output, but output is further adjusted by changes in translational efficiency. RNAs with prioritized translation early in development are largely involved in chloroplast gene expression, whereas those with prioritized translation in photosynthetic tissues are generally involved in photosynthesis. Differential gene expression in bundle sheath and mesophyll chloroplasts results primarily from differences in mRNA abundance, but differences in translational efficiency amplify mRNA-level effects in some instances. In most cases, rates of protein output approximate steady-state protein stoichiometries, implying a limited role for proteolysis in eliminating unassembled or damaged proteins under non-stress conditions. Tuned protein output results from gene-specific trade-offs between translational efficiency and mRNA abundance, both of which span a large dynamic range. Analysis of ribosome footprints at sites of RNA editing showed that the chloroplast translation machinery does not generally discriminate between edited and unedited RNAs. However, editing of ACG to AUG at the rpl2 start codon is essential for translation initiation, demonstrating that ACG does not serve as a start codon in maize chloroplasts.
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Affiliation(s)
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
- * E-mail:
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46
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Breiman A, Fieulaine S, Meinnel T, Giglione C. The intriguing realm of protein biogenesis: Facing the green co-translational protein maturation networks. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1864:531-50. [PMID: 26555180 DOI: 10.1016/j.bbapap.2015.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/05/2015] [Indexed: 01/13/2023]
Abstract
The ribosome is the cell's protein-making factory, a huge protein-RNA complex, that is essential to life. Determining the high-resolution structures of the stable "core" of this factory was among the major breakthroughs of the past decades, and was awarded the Nobel Prize in 2009. Now that the mysteries of the ribosome appear to be more traceable, detailed understanding of the mechanisms that regulate protein synthesis includes not only the well-known steps of initiation, elongation, and termination but also the less comprehended features of the co-translational events associated with the maturation of the nascent chains. The ribosome is a platform for co-translational events affecting the nascent polypeptide, including protein modifications, folding, targeting to various cellular compartments for integration into membrane or translocation, and proteolysis. These events are orchestrated by ribosome-associated protein biogenesis factors (RPBs), a group of a dozen or more factors that act as the "welcoming committee" for the nascent chain as it emerges from the ribosome. In plants these factors have evolved to fit the specificity of different cellular compartments: cytoplasm, mitochondria and chloroplast. This review focuses on the current state of knowledge of these factors and their interaction around the exit tunnel of dedicated ribosomes. Particular attention has been accorded to the plant system, highlighting the similarities and differences with other organisms.
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Affiliation(s)
- Adina Breiman
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay 91198 Gif-sur-Yvette cedex, France; Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel
| | - Sonia Fieulaine
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay 91198 Gif-sur-Yvette cedex, France
| | - Thierry Meinnel
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay 91198 Gif-sur-Yvette cedex, France
| | - Carmela Giglione
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay 91198 Gif-sur-Yvette cedex, France.
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