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Su T, Zhang XF, Wu GZ. Functional conservation of GENOMES UNCOUPLED1 in plastid-to-nucleus retrograde signaling in tomato. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 343:112053. [PMID: 38417718 DOI: 10.1016/j.plantsci.2024.112053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/20/2024] [Accepted: 02/24/2024] [Indexed: 03/01/2024]
Abstract
Retrograde signaling between plastids and the nucleus is vital for chloroplast biogenesis and environmental responses. GENOMES UNCOUPLED1 (GUN1) was proposed to be a central integrator of multiple retrograde signaling pathways in the model plant Arabidopsis thaliana (Arabidopsis). However, the function of GUN1 orthologs in other plant species has not been well studied. Here, we found that many GUN1 orthologs from the Solanaceae family have a short N-terminus before the first pentatricopeptide repeat (PPR) motif which is predicted as intrinsically disordered regions (IDRs). Functional analyses of tomato (Solanum lycopersicum L.) GUN1 (SlGUN1), which does not contain N-terminal IDRs, show that it can complement the GUN phenotype of the Arabidopsis gun1 mutant (Atgun1). However, in contrast to the AtGUN1 protein, which does contain the N-terminal IDRs, the SlGUN1 protein is highly accumulated even after chloroplast biogenesis is completed, suggesting that the N-terminal IDRs may determine the stability of the GUN1 protein. Furthermore, we generated tomato Slgun1 genome-edited mutants via the CRISPR-Cas9 system. The Slgun1 mutants exhibited a typical GUN phenotype under lincomycin (Lin) or norflurazon (NF) treatment. Moreover, Slgun1 mutants are hypersensitive to low concentrations of Lin or NF. Taken together, our results suggest that, although lacking the N-terminal IDRs, SlGUN1 plays conserved roles in plastid retrograde signaling in tomato plants.
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Affiliation(s)
- Tong Su
- Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Xiao-Fan Zhang
- Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Guo-Zhang Wu
- Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China.
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2
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Kwok van der Giezen F, Honkanen S, Colas des Francs-Small C, Bond C, Small I. Applications of Synthetic Pentatricopeptide Repeat Proteins. PLANT & CELL PHYSIOLOGY 2024; 65:503-515. [PMID: 38035801 PMCID: PMC11094755 DOI: 10.1093/pcp/pcad150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/20/2023] [Accepted: 11/29/2023] [Indexed: 12/02/2023]
Abstract
RNA-binding proteins play integral roles in the regulation of essential processes in cells and as such are attractive targets for engineering to manipulate gene expression at the RNA level. Expression of transcripts in chloroplasts and mitochondria is heavily regulated by pentatricopeptide repeat (PPR) proteins. The diverse roles of PPR proteins and their naturally modular architecture make them ideal candidates for engineering. Synthetic PPR proteins are showing great potential to become valuable tools for controlling the expression of plastid and mitochondrial transcripts. In this review, by 'synthetic', we mean both rationally modified natural PPR proteins and completely novel proteins designed using the principles learned from their natural counterparts. We focus on the many different applications of synthetic PPR proteins, covering both their use in basic research to learn more about protein-RNA interactions and their use to achieve specific outcomes in RNA processing and the control of gene expression. We describe the challenges associated with the design, construction and deployment of synthetic PPR proteins and provide perspectives on how they might be assembled and used in future biotechnology applications.
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Affiliation(s)
- Farley Kwok van der Giezen
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Suvi Honkanen
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Catherine Colas des Francs-Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Charles Bond
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
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Yi S, Guo X, Lou W, Mao S, Luan G, Lu X. Structure, Regulation, and Significance of Cyanobacterial and Chloroplast Adenosine Triphosphate Synthase in the Adaptability of Oxygenic Photosynthetic Organisms. Microorganisms 2024; 12:940. [PMID: 38792770 PMCID: PMC11124002 DOI: 10.3390/microorganisms12050940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
In cyanobacteria and chloroplasts (in algae and plants), ATP synthase plays a pivotal role as a photosynthetic membrane complex responsible for producing ATP from adenosine diphosphate and inorganic phosphate, utilizing a proton motive force gradient induced by photosynthesis. These two ATP synthases exhibit similarities in gene organization, amino acid sequences of subunits, structure, and functional mechanisms, suggesting that cyanobacterial ATP synthase is probably the evolutionary precursor to chloroplast ATP synthase. In this review, we explore the precise synthesis and assembly of ATP synthase subunits to address the uneven stoichiometry within the complex during transcription, translation, and assembly processes. We also compare the regulatory strategies governing ATP synthase activity to meet varying energy demands in cyanobacteria and chloroplasts amid fluctuating natural environments. Furthermore, we delve into the role of ATP synthase in stress tolerance and photosynthetic carbon fixation efficiency in oxygenic photosynthetic organisms (OPsOs), along with the current researches on modifying ATP synthase to enhance carbon fixation efficiency under stress conditions. This review aims to offer theoretical insights and serve as a reference for understanding the functional mechanisms of ATP synthase, sparking innovative ideas for enhancing photosynthetic carbon fixation efficiency by utilizing ATP synthase as an effective module in OPsOs.
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Affiliation(s)
- Siyan Yi
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China;
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry & Technology, Changsha 410004, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (X.G.); (G.L.); (X.L.)
| | - Xin Guo
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (X.G.); (G.L.); (X.L.)
- College of Live Science, Henan University, Kaifeng 450001, China
| | - Wenjing Lou
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (X.G.); (G.L.); (X.L.)
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
| | - Shaoming Mao
- College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China;
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry & Technology, Changsha 410004, China
| | - Guodong Luan
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (X.G.); (G.L.); (X.L.)
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
| | - Xuefeng Lu
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (X.G.); (G.L.); (X.L.)
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
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4
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K. Raval P, MacLeod AI, Gould SB. A molecular atlas of plastid and mitochondrial proteins reveals organellar remodeling during plant evolutionary transitions from algae to angiosperms. PLoS Biol 2024; 22:e3002608. [PMID: 38713727 PMCID: PMC11135702 DOI: 10.1371/journal.pbio.3002608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 05/29/2024] [Accepted: 03/28/2024] [Indexed: 05/09/2024] Open
Abstract
Algae and plants carry 2 organelles of endosymbiotic origin that have been co-evolving in their host cells for more than a billion years. The biology of plastids and mitochondria can differ significantly across major lineages and organelle changes likely accompanied the adaptation to new ecological niches such as the terrestrial habitat. Based on organelle proteome data and the genomes of 168 phototrophic (Archaeplastida) versus a broad range of 518 non-phototrophic eukaryotes, we screened for changes in plastid and mitochondrial biology across 1 billion years of evolution. Taking into account 331,571 protein families (or orthogroups), we identify 31,625 protein families that are unique to primary plastid-bearing eukaryotes. The 1,906 and 825 protein families are predicted to operate in plastids and mitochondria, respectively. Tracing the evolutionary history of these protein families through evolutionary time uncovers the significant remodeling the organelles experienced from algae to land plants. The analyses of gained orthogroups identifies molecular changes of organelle biology that connect to the diversification of major lineages and facilitated major transitions from chlorophytes en route to the global greening and origin of angiosperms.
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Affiliation(s)
- Parth K. Raval
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alexander I. MacLeod
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sven B. Gould
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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Huynh SD, Melonek J, Colas des Francs-Small C, Bond CS, Small I. A unique C-terminal domain contributes to the molecular function of Restorer-of-fertility proteins in plant mitochondria. THE NEW PHYTOLOGIST 2023; 240:830-845. [PMID: 37551058 DOI: 10.1111/nph.19166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/10/2023] [Indexed: 08/09/2023]
Abstract
Restorer-of-fertility (Rf) genes encode pentatricopeptide repeat (PPR) proteins that are targeted to mitochondria where they specifically bind to transcripts that induce cytoplasmic male sterility and repress their expression. In searching for a molecular signature unique to this class of proteins, we found that a majority of known Rf proteins have a distinct domain, which we called RfCTD (Restorer-of-fertility C-terminal domain), and its presence correlates with the ability to induce cleavage of the mitochondrial RNA target. A screen of 219 angiosperm genomes from 123 genera using a sequence profile that can quickly and accurately identify RfCTD sequences revealed considerable variation in RFL/RfCTD gene numbers across flowering plants. We observed that plant genera with bisexual flowers have significantly higher numbers of RFL genes compared to those with unisexual flowers, consistent with a role of these proteins in restoration of male fertility. We show that removing the RfCTD from the RFL protein RNA PROCESSING FACTOR 2-nad6 prevented cleavage of its RNA target, the nad6 transcript, in Arabidopsis thaliana mitochondria. We provide a simple way of identifying putative Rf candidates in genome sequences, new insights into the molecular mode of action of Rf proteins and the evolution of fertility restoration in flowering plants.
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Affiliation(s)
- Sang Dang Huynh
- School of Molecular Sciences, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Joanna Melonek
- School of Molecular Sciences, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Catherine Colas des Francs-Small
- School of Molecular Sciences, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Charles S Bond
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Ian Small
- School of Molecular Sciences, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA, 6009, Australia
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Zhang Y, Tian L, Lu C. Chloroplast gene expression: Recent advances and perspectives. PLANT COMMUNICATIONS 2023; 4:100611. [PMID: 37147800 PMCID: PMC10504595 DOI: 10.1016/j.xplc.2023.100611] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/11/2023] [Accepted: 05/01/2023] [Indexed: 05/07/2023]
Abstract
Chloroplasts evolved from an ancient cyanobacterial endosymbiont more than 1.5 billion years ago. During subsequent coevolution with the nuclear genome, the chloroplast genome has remained independent, albeit strongly reduced, with its own transcriptional machinery and distinct features, such as chloroplast-specific innovations in gene expression and complicated post-transcriptional processing. Light activates the expression of chloroplast genes via mechanisms that optimize photosynthesis, minimize photodamage, and prioritize energy investments. Over the past few years, studies have moved from describing phases of chloroplast gene expression to exploring the underlying mechanisms. In this review, we focus on recent advances and emerging principles that govern chloroplast gene expression in land plants. We discuss engineering of pentatricopeptide repeat proteins and its biotechnological effects on chloroplast RNA research; new techniques for characterizing the molecular mechanisms of chloroplast gene expression; and important aspects of chloroplast gene expression for improving crop yield and stress tolerance. We also discuss biological and mechanistic questions that remain to be answered in the future.
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Affiliation(s)
- Yi Zhang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Lin Tian
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Congming Lu
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China.
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Honkanen S, Small I. The GENOMES UNCOUPLED1 protein has an ancient, highly conserved role but not in retrograde signalling. THE NEW PHYTOLOGIST 2022; 236:99-113. [PMID: 35708656 PMCID: PMC9545484 DOI: 10.1111/nph.18318] [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: 03/05/2022] [Accepted: 06/07/2022] [Indexed: 06/01/2023]
Abstract
The pentatricopeptide repeat protein GENOMES UNCOUPLED1 (GUN1) is required for chloroplast-to-nucleus signalling when plastid translation becomes inhibited during chloroplast development in Arabidopsis thaliana, but its exact molecular function remains unknown. We analysed GUN1 sequences in land plants and streptophyte algae. We tested functional conservation by complementation of the Arabidopsis gun1 mutant with GUN1 genes from the streptophyte alga Coleochate orbicularis or the liverwort Marchantia polymorpha. We also analysed the transcriptomes of M. polymorpha gun1 knockout mutant lines during chloroplast development. GUN1 evolved within the streptophyte algal ancestors of land plants and is highly conserved among land plants but missing from the Rafflesiaceae that lack chloroplast genomes. GUN1 genes from C. orbicularis and M. polymorpha suppress the cold-sensitive phenotype of the Arabidopsis gun1 mutant and restore typical retrograde responses to treatments with inhibitors of plastid translation, even though M. polymorpha responds very differently to such treatments. Our findings suggest that GUN1 is an ancient protein that evolved within the streptophyte algal ancestors of land plants before the first plants colonized land more than 470 million years ago. Its primary role is likely to be in chloroplast gene expression and its role in chloroplast retrograde signalling probably evolved more recently.
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Affiliation(s)
- Suvi Honkanen
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular SciencesThe University of Western AustraliaCrawleyWA6009Australia
| | - Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular SciencesThe University of Western AustraliaCrawleyWA6009Australia
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8
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Andrade-Marcial M, Pacheco-Arjona R, Góngora-Castillo E, De-la-Peña C. Chloroplastic pentatricopeptide repeat proteins (PPR) in albino plantlets of Agave angustifolia Haw. reveal unexpected behavior. BMC PLANT BIOLOGY 2022; 22:352. [PMID: 35850575 PMCID: PMC9295523 DOI: 10.1186/s12870-022-03742-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Pentatricopeptide repeat (PPR) proteins play an essential role in the post-transcriptional regulation of genes in plastid genomes. Although important advances have been made in understanding the functions of these genes, there is little information available on chloroplastic PPR genes in non-model plants and less in plants without chloroplasts. In the present study, a comprehensive and multifactorial bioinformatic strategy was applied to search for putative PPR genes in the foliar and meristematic tissues of green and albino plantlets of the non-model plant Agave angustifolia Haw. RESULTS A total of 1581 PPR transcripts were identified, of which 282 were chloroplastic. Leaf tissue in the albino plantlets showed the highest levels of expression of chloroplastic PPRs. The search for hypothetical targets of 12 PPR sequences in the chloroplast genes of A. angustifolia revealed their action on transcripts related to ribosomes and translation, photosystems, ATP synthase, plastid-encoded RNA polymerase and RuBisCO. CONCLUSIONS Our results suggest that the expression of PPR genes depends on the state of cell differentiation and plastid development. In the case of the albino leaf tissue, which lacks functional chloroplasts, it is possible that anterograde and retrograde signaling networks are severely compromised, leading to a compensatory anterograde response characterized by an increase in the expression of PPR genes.
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Affiliation(s)
- M Andrade-Marcial
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - R Pacheco-Arjona
- Facultad de Medicina Veterinaria y Zootecnia, Consejo Nacional de Ciencia y Tecnología- Universidad Autónoma de Yucatán, Mérida, Mexico
| | - E Góngora-Castillo
- Consejo Nacional de Ciencia y Tecnología-Unidad De Biotecnología, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - C De-la-Peña
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico.
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CAF Proteins Help SOT1 Regulate the Stability of Chloroplast ndhA Transcripts. Int J Mol Sci 2021; 22:ijms222312639. [PMID: 34884441 PMCID: PMC8657633 DOI: 10.3390/ijms222312639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/20/2021] [Accepted: 11/20/2021] [Indexed: 12/26/2022] Open
Abstract
Protein-mediated RNA stabilization plays profound roles in chloroplast gene expression. Genetic studies have indicated that chloroplast ndhA transcripts, encoding a key subunit of the NADH dehydrogenase-like complex that mediates photosystem I cyclic electron transport and facilitates chlororespiration, are stabilized by PPR53 and its orthologs, but the underlying mechanisms are unclear. Here, we report that CHLOROPLAST RNA SPLICING 2 (CRS2)-ASSOCIATED FACTOR (CAF) proteins activate SUPPRESSOR OF THYLAKOID FORMATION 1 (SOT1), an ortholog of PPR53 in Arabidopsis thaliana, enhancing their affinity for the 5' ends of ndhA transcripts to stabilize these molecules while inhibiting the RNA endonuclease activity of the SOT1 C-terminal SMR domain. In addition, we established that SOT1 improves the splicing efficiency of ndhA by facilitating the association of CAF2 with the ndhA intron, which may be due to the SOT1-mediated stability of the ndhA transcripts. Our findings shed light on the importance of PPR protein interaction partners in moderating RNA metabolism.
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Wu GZ, Bock R. GUN control in retrograde signaling: How GENOMES UNCOUPLED proteins adjust nuclear gene expression to plastid biogenesis. THE PLANT CELL 2021; 33:457-474. [PMID: 33955483 PMCID: PMC8136882 DOI: 10.1093/plcell/koaa048] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/03/2020] [Indexed: 05/08/2023]
Abstract
Communication between cellular compartments is vital for development and environmental adaptation. Signals emanating from organelles, so-called retrograde signals, coordinate nuclear gene expression with the developmental stage and/or the functional status of the organelle. Plastids (best known in their green photosynthesizing differentiated form, the chloroplasts) are the primary energy-producing compartment of plant cells, and the site for the biosynthesis of many metabolites, including fatty acids, amino acids, nucleotides, isoprenoids, tetrapyrroles, vitamins, and phytohormone precursors. Signals derived from plastids regulate the accumulation of a large set of nucleus-encoded proteins, many of which localize to plastids. A set of mutants defective in retrograde signaling (genomes uncoupled, or gun) was isolated over 25 years ago. While most GUN genes act in tetrapyrrole biosynthesis, resolving the molecular function of GUN1, the proposed integrator of multiple retrograde signals, has turned out to be particularly challenging. Based on its amino acid sequence, GUN1 was initially predicted to be a plastid-localized nucleic acid-binding protein. Only recently, mechanistic information on the function of GUN1 has been obtained, pointing to a role in plastid protein homeostasis. This review article summarizes our current understanding of GUN-related retrograde signaling and provides a critical appraisal of the various proposed roles for GUNs and their respective pathways.
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Affiliation(s)
- Guo-Zhang Wu
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240 Shanghai, China
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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The Arabidopsis NOT4A E3 ligase promotes PGR3 expression and regulates chloroplast translation. Nat Commun 2021; 12:251. [PMID: 33431870 PMCID: PMC7801604 DOI: 10.1038/s41467-020-20506-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022] Open
Abstract
Chloroplast function requires the coordinated action of nuclear- and chloroplast-derived proteins, including several hundred nuclear-encoded pentatricopeptide repeat (PPR) proteins that regulate plastid mRNA metabolism. Despite their large number and importance, regulatory mechanisms controlling PPR expression are poorly understood. Here we show that the Arabidopsis NOT4A ubiquitin-ligase positively regulates the expression of PROTON GRADIENT REGULATION 3 (PGR3), a PPR protein required for translating several thylakoid-localised photosynthetic components and ribosome subunits within chloroplasts. Loss of NOT4A function leads to a strong depletion of cytochrome b6f and NAD(P)H dehydrogenase (NDH) complexes, as well as plastid 30 S ribosomes, which reduces mRNA translation and photosynthetic capacity, causing pale-yellow and slow-growth phenotypes. Quantitative transcriptome and proteome analysis of the not4a mutant reveal it lacks PGR3 expression, and that its molecular defects resemble those of a pgr3 mutant. Furthermore, we show that normal plastid function is restored to not4a through transgenic PGR3 expression. Our work identifies NOT4A as crucial for ensuring robust photosynthetic function during development and stress-response, through promoting PGR3 production and chloroplast translation.
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12
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Su HG, Li B, Song XY, Ma J, Chen J, Zhou YB, Chen M, Min DH, Xu ZS, Ma YZ. Genome-Wide Analysis of the DYW Subgroup PPR Gene Family and Identification of GmPPR4 Responses to Drought Stress. Int J Mol Sci 2019; 20:E5667. [PMID: 31726763 PMCID: PMC6888332 DOI: 10.3390/ijms20225667] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/25/2019] [Accepted: 11/06/2019] [Indexed: 12/11/2022] Open
Abstract
Pentatricopeptide-repeat (PPR) proteins were identified as a type of nucleus coding protein that is composed of multiple tandem repeats. It has been reported that PPR genes play an important role in RNA editing, plant growth and development, and abiotic stresses in plants. However, the functions of PPR proteins remain largely unknown in soybean. In this study, 179 DYW subgroup PPR genes were identified in soybean genome (Glycine max Wm82.a2.v1). Chromosomal location analysis indicated that DYW subgroup PPR genes were mapped to all 20 chromosomes. Phylogenetic relationship analysis revealed that DYW subgroup PPR genes were categorized into three distinct Clusters (I to III). Gene structure analysis showed that most PPR genes were featured by a lack of intron. Gene duplication analysis demonstrated 30 PPR genes (15 pairs; ~35.7%) were segmentally duplicated among Cluster I PPR genes. Furthermore, we validated the mRNA expression of three genes that were highly up-regulated in soybean drought- and salt-induced transcriptome database and found that the expression levels of GmPPR4 were induced under salt and drought stresses. Under drought stress condition, GmPPR4-overexpressing (GmPPR4-OE) plants showed delayed leaf rolling; higher content of proline (Pro); and lower contents of H2O2, O2- and malondialdehyde (MDA) compared with the empty vector (EV)-control plants. GmPPR4-OE plants exhibited increased transcripts of several drought-inducible genes compared with EV-control plants. Our results provided a comprehensive analysis of the DYW subgroup PPR genes and an insight for improving the drought tolerance in soybean.
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Affiliation(s)
- Hong-Gang Su
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China;
| | - Bo Li
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
| | - Xin-Yuan Song
- Agro-Biotechnology Research Institute, Jilin Academy of Agriculture Sciences, Changchun 130033, China;
| | - Jian Ma
- College of Agronomy, Jilin Agricultural University, Changchun 130118, China;
| | - Jun Chen
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
| | - Yong-Bin Zhou
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
| | - Ming Chen
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
| | - Dong-Hong Min
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China;
| | - Zhao-Shi Xu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
| | - You-Zhi Ma
- Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; (H.-G.S.); (B.L.); (J.C.); (Y.-B.Z.); (M.C.)
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Yuan N, Wang J, Zhou Y, An D, Xiao Q, Wang W, Wu Y. EMB-7L is required for embryogenesis and plant development in maize involved in RNA splicing of multiple chloroplast genes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 287:110203. [PMID: 31481208 DOI: 10.1016/j.plantsci.2019.110203] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 05/21/2023]
Abstract
Embryo and endosperm originate from the double fertilization, but they have different developmental fates and biological functions. We identified a previously undescribed maize seed mutant, wherein the embryo appears to be more severely affected than the endosperm (embryo-specific, emb). In the W22 background, the emb embryo arrests at the transition stage whereas its endosperm appears nearly normal in size. At maturity, the embryo in W22-emb is apparently small or even invisible. In contrast, the emb endosperm develops into a relative normal size. We cloned the mutant gene on the Chromosome 7L and designated it emb-7L. This gene is generally expressed, but it has a relatively higher expression level in leaves. Emb-7L encodes a chloroplast-localized P-type pentatricopeptide repeat (PPR) protein, consistent with the severe chloroplast deficiency in emb-7L albino seedling leaves. Full transcriptome analysis of the leaves of WT and emb-7L seedlings reveals that transcription of chloroplast protein-encoding genes are dramatically variable with pre-mRNA intron splicing apparently affected in a tissue-dependent pattern and the chloroplast structure and activity were dramatically affected including chloroplast membrane and photosynthesis machinery component and synthesis of metabolic products (e.g., fatty acids, amino acids, starch).
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Affiliation(s)
- Ningning Yuan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jiechen Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yong Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Dong An
- College of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiao Xiao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wenqin Wang
- College of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Yongrui Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
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14
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Rojas M, Ruwe H, Miranda RG, Zoschke R, Hase N, Schmitz-Linneweber C, Barkan A. Unexpected functional versatility of the pentatricopeptide repeat proteins PGR3, PPR5 and PPR10. Nucleic Acids Res 2019; 46:10448-10459. [PMID: 30125002 PMCID: PMC6212717 DOI: 10.1093/nar/gky737] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/06/2018] [Indexed: 02/02/2023] Open
Abstract
Pentatricopeptide repeat (PPR) proteins are a large family of helical repeat proteins that bind RNA in mitochondria and chloroplasts. Sites of PPR action have been inferred primarily from genetic data, which have led to the view that most PPR proteins act at a very small number of sites in vivo. Here, we report new functions for three chloroplast PPR proteins that had already been studied in depth. Maize PPR5, previously shown to promote trnG splicing, is also required for rpl16 splicing. Maize PPR10, previously shown to bind the atpI-atpH and psaJ-rpl33 intercistronic regions, also stabilizes a 3′-end downstream from psaI. Arabidopsis PGR3, shown previously to bind upstream of petL, also binds the rpl14-rps8 intercistronic region where it stabilizes a 3′-end and stimulates rps8 translation. These functions of PGR3 are conserved in maize. The discovery of new functions for three proteins that were already among the best characterized members of the PPR family implies that functional repertoires of PPR proteins are more complex than have been appreciated. The diversity of sequences bound by PPR10 and PGR3 in vivo highlights challenges of predicting binding sites of native PPR proteins based on the amino acid code for nucleotide recognition by PPR motifs.
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Affiliation(s)
- Margarita Rojas
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Hannes Ruwe
- Department of Life Sciences, Institute of Biology, Humboldt University Berlin, 10115 Berlin, Germany
| | - Rafael G Miranda
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Reimo Zoschke
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Nora Hase
- Department of Life Sciences, Institute of Biology, Humboldt University Berlin, 10115 Berlin, Germany
| | | | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
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15
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Zhang Y, Lu C. The Enigmatic Roles of PPR-SMR Proteins in Plants. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900361. [PMID: 31380188 PMCID: PMC6662315 DOI: 10.1002/advs.201900361] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/03/2019] [Indexed: 05/21/2023]
Abstract
The pentatricopeptide repeat (PPR) protein family, with more than 400 members, is one of the largest and most diverse protein families in land plants. A small subset of PPR proteins contain a C-terminal small MutS-related (SMR) domain. Although there are relatively few PPR-SMR proteins, they play essential roles in embryo development, chloroplast biogenesis and gene expression, and plastid-to-nucleus retrograde signaling. Here, recent advances in understanding the roles of PPR-SMR proteins and the SMR domain based on a combination of genetic, biochemical, and physiological analyses are described. In addition, the potential of the PPR-SMR protein SOT1 to serve as a tool for RNA manipulation is highlighted.
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Affiliation(s)
- Yi Zhang
- State Key Laboratory of Crop BiologyCollege of Life SciencesShandong Agricultural UniversityTaianShandong271018P. R. China
| | - Congming Lu
- State Key Laboratory of Crop BiologyCollege of Life SciencesShandong Agricultural UniversityTaianShandong271018P. R. China
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16
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Dogra V, Duan J, Lee KP, Kim C. Impaired PSII proteostasis triggers a UPR-like response in the var2 mutant of Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3075-3088. [PMID: 30989223 PMCID: PMC6598079 DOI: 10.1093/jxb/erz151] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/25/2019] [Indexed: 05/18/2023]
Abstract
Cellular protein homeostasis (proteostasis) is maintained through the balance between de novo synthesis and proteolysis. The unfolded/misfolded protein response (UPR) that is triggered by stressed endoplasmic reticulum (ER) also plays an important role in proteostasis in both plants and animals. Although ER-triggered UPR has been extensively studied in plants, the molecular mechanisms underlying mitochondrial and chloroplastic UPRs are largely uncharacterized despite the fact that these organelles are sites of production of harmful reactive oxygen species (ROS), which damage proteins. In this study, we demonstrate that chloroplasts of the Arabidopsis yellow leaf variegation 2 (var2) mutant, which lacks the metalloprotease FtsH2, accumulate damaged chloroplast proteins and trigger a UPR-like response, namely the accumulation of a suite of chloroplast proteins involved in protein quality control (PQC). These PQC proteins include heat-shock proteins, chaperones, proteases, and ROS detoxifiers. Given that FtsH2 functions primarily in photosystem II proteostasis, the accumulation of PQC-related proteins may balance the FtsH2 deficiency. Moreover, the apparent up-regulation of the cognate transcripts indicates that the accumulation of PQC-related proteins in var2 is probably mediated by retrograde signaling, indicating the occurrence of a UPR-like response in var2.
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Affiliation(s)
- Vivek Dogra
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jianli Duan
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Keun Pyo Lee
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- Correspondence:
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17
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Zhang L, Zhou W, Che L, Rochaix JD, Lu C, Li W, Peng L. PPR Protein BFA2 Is Essential for the Accumulation of the atpH/F Transcript in Chloroplasts. FRONTIERS IN PLANT SCIENCE 2019; 10:446. [PMID: 31031784 PMCID: PMC6474325 DOI: 10.3389/fpls.2019.00446] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 03/25/2019] [Indexed: 05/04/2023]
Abstract
As a fascinating and complicated nanomotor, chloroplast ATP synthase comprises nine subunits encoded by both the nuclear and plastid genomes. Because of its uneven subunit stoichiometry, biogenesis of ATP synthase and expression of plastid-encoded ATP synthase genes requires assistance by nucleus-encoded factors involved in transcriptional, post-transcriptional, and translational steps. In this study, we report a P-class pentatricopeptide repeat (PPR) protein BFA2 (Biogenesis Factor required for ATP synthase 2) that is essential for accumulation of the dicistronic atpH/F transcript in Arabidopsis chloroplasts. A loss-of-function mutation in BFA2 results in a specific reduction of more than 3/4 of chloroplast ATP synthase, which is likely due to the absence of dicistronic atpH/F transcript. BFA2 protein contains 22 putative PPR motifs and exclusively localizes in the chloroplast. Bioinformatics and Electrophoretic Mobility Shift Assays (EMSA) analysis showed that BFA2 binds to the consensus sequence of the atpF-atpA intergenic region in a sequence-specific manner. However, translation initiation of the atpA was not affected in the bfa2 mutant. Thus, we propose that the chloroplast PPR protein BFA2 mainly acts as barrier to prevent the atpH/F transcript degradation by exoribonucleases by binding to the consensus sequence of the atpF-atpA intergenic region.
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Affiliation(s)
- Lin Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Wen Zhou
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Liping Che
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jean-David Rochaix
- Departments of Molecular Biology and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Congming Lu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Wenjing Li
- College of Life Sciences, Langfang Normal University, Langfang, China
- *Correspondence: Wenjing Li, Lianwei Peng,
| | - Lianwei Peng
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
- *Correspondence: Wenjing Li, Lianwei Peng,
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18
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Zhang S, Zhang H, Xia Y, Xiong L. The caseinolytic protease complex component CLPC1 in Arabidopsis maintains proteome and RNA homeostasis in chloroplasts. BMC PLANT BIOLOGY 2018; 18:192. [PMID: 30208840 PMCID: PMC6136230 DOI: 10.1186/s12870-018-1396-0] [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: 01/01/2018] [Accepted: 08/27/2018] [Indexed: 05/18/2023]
Abstract
BACKGROUND Homeostasis of the proteome is critical to the development of chloroplasts and also affects the expression of certain nuclear genes. CLPC1 facilitates the translocation of chloroplast pre-proteins and mediates protein degradation. RESULTS We found that proteins involved in photosynthesis are dramatically decreased in their abundance in the clpc1 mutant, whereas many proteins involved in chloroplast transcription and translation were increased in the mutant. Expression of the full-length CLPC1 protein, but not of the N-terminus-deleted CLPC1 (ΔN), in the clpc1 mutant background restored the normal levels of most of these proteins. Interestingly, the ΔN complementation line could also restore some proteins affected by the mutation to normal levels. We also found that that the clpc1 mutation profoundly affects transcript levels of chloroplast genes. Sense transcripts of many chloroplast genes are up-regulated in the clpc1 mutant. The level of SVR7, a PPR protein, was affected by the clpc1 mutation. We showed that SVR7 might be a target of CLPC1 as CLPC1-SVR7 interaction was detected through co-immunoprecipitation. CONCLUSION Our study indicates that in addition to its role in maintaining proteome homeostasis, CLPC1 and likely the CLP proteasome complex also play a role in transcriptome homeostasis through its functions in maintaining proteome homeostasis.
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Affiliation(s)
- Shoudong Zhang
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
- Centre for Soybean Research, Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, Special Administrative Region China
| | - Huoming Zhang
- Core labs, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
| | - Yiji Xia
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
- Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Shatin, Hong Kong SAR, China
- Partner State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
| | - Liming Xiong
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900 Saudi Arabia
- Texas A&M AgriLife Research Center, Dallas, TX 75252 USA
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843 USA
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19
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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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20
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RNA-stabilization factors in chloroplasts of vascular plants. Essays Biochem 2018; 62:51-64. [PMID: 29453323 PMCID: PMC5897788 DOI: 10.1042/ebc20170061] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/02/2018] [Accepted: 01/12/2018] [Indexed: 12/23/2022]
Abstract
In contrast to the cyanobacterial ancestor, chloroplast gene expression is predominantly governed on the post-transcriptional level such as modifications of the RNA sequence, decay rates, exo- and endonucleolytic processing as well as translational events. The concerted function of numerous chloroplast RNA-binding proteins plays a fundamental and often essential role in all these processes but our understanding of their impact in regulation of RNA degradation is only at the beginning. Moreover, metabolic processes and post-translational modifications are thought to affect the function of RNA protectors. These protectors contain a variety of different RNA-recognition motifs, which often appear as multiple repeats. They are required for normal plant growth and development as well as diverse stress responses and acclimation processes. Interestingly, most of the protectors are plant specific which reflects a fast-evolving RNA metabolism in chloroplasts congruent with the diverging RNA targets. Here, we mainly focused on the characteristics of known chloroplast RNA-binding proteins that protect exonuclease-sensitive sites in chloroplasts of vascular plants.
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21
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Mohanta TK, Bashir T, Hashem A, Abd Allah EF, Bae H. Genome Editing Tools in Plants. Genes (Basel) 2017; 8:E399. [PMID: 29257124 PMCID: PMC5748717 DOI: 10.3390/genes8120399] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/08/2017] [Accepted: 12/15/2017] [Indexed: 12/23/2022] Open
Abstract
Genome editing tools have the potential to change the genomic architecture of a genome at precise locations, with desired accuracy. These tools have been efficiently used for trait discovery and for the generation of plants with high crop yields and resistance to biotic and abiotic stresses. Due to complex genomic architecture, it is challenging to edit all of the genes/genomes using a particular genome editing tool. Therefore, to overcome this challenging task, several genome editing tools have been developed to facilitate efficient genome editing. Some of the major genome editing tools used to edit plant genomes are: Homologous recombination (HR), zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), pentatricopeptide repeat proteins (PPRs), the CRISPR/Cas9 system, RNA interference (RNAi), cisgenesis, and intragenesis. In addition, site-directed sequence editing and oligonucleotide-directed mutagenesis have the potential to edit the genome at the single-nucleotide level. Recently, adenine base editors (ABEs) have been developed to mutate A-T base pairs to G-C base pairs. ABEs use deoxyadeninedeaminase (TadA) with catalytically impaired Cas9 nickase to mutate A-T base pairs to G-C base pairs.
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Affiliation(s)
| | - Tufail Bashir
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Korea.
| | - Abeer Hashem
- Botany and Microbiology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
- Mycology and Plant Disease Survey Department, Plant Pathology Research Institute, Agriculture Research Center, Giza 12619, Egypt.
| | - Elsayed Fathi Abd Allah
- Plant Production Department, College of Food and Agriculture Science, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Hanhong Bae
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Korea.
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22
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Liu YJ, Liu X, Chen H, Zheng P, Wang W, Wang L, Zhang J, Tu J. A Plastid-Localized Pentatricopeptide Repeat Protein is Required for Both Pollen Development and Plant Growth in Rice. Sci Rep 2017; 7:11484. [PMID: 28904339 PMCID: PMC5597598 DOI: 10.1038/s41598-017-10727-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/14/2017] [Indexed: 11/18/2022] Open
Abstract
Several mitochondrial-targeted pentatricopeptide repeat (PPR) proteins involved in pollen development have been reported to be fertility restorer (Rf) proteins. However, the roles of plastid-localized PPR proteins in plant male reproduction are poorly defined. Here, we described a plastid-localized PPR-SMR protein, OsPPR676, which is required for plant growth and pollen development in rice. In this study, OsPPR676 was confirmed to be an interacted protein with Osj10gBTF3, β-subunit of nascent polypeptide-associated complex (β-NAC), by bimolecular fluorescence complementation assays, indicating that both proteins are probably involved in the same regulatory pathway of pollen development. Compared with other chloroplast-rich tissues, OsPPR676 was only weakly expressed in anther, but in the Mei and YM stages of pollen development, its expression was relatively strong in the tapetum. Disruption of OsPPR676 resulted in growth retardation of plants and partial sterility of pollens. Phenotypic analysis of different osppr676 mutant lines implied that the SMR domain was not essential for the function of OsPPR676. We further demonstrated that OsPPR676 is essential for production of plastid atpB subunit, and then plays crucial roles in biosynthesis of fatty acids, carbohydrates, and other organic matters via affecting activity of ATP synthase.
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Affiliation(s)
- Yu-Jun Liu
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China.,State Key Lab of Agrobiotechnology, School of Life Science, The Chinese University of Hong Kong, N.T., Hong Kong, P. R. China
| | - Xuejiao Liu
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China
| | - Hao Chen
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China
| | - Peng Zheng
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China
| | - Wenyi Wang
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China
| | - Liangchao Wang
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China
| | - Jianhua Zhang
- State Key Lab of Agrobiotechnology, School of Life Science, The Chinese University of Hong Kong, N.T., Hong Kong, P. R. China.
| | - Jumin Tu
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, P. R. China.
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23
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Ferrari R, Tadini L, Moratti F, Lehniger MK, Costa A, Rossi F, Colombo M, Masiero S, Schmitz-Linneweber C, Pesaresi P. CRP1 Protein: (dis)similarities between Arabidopsis thaliana and Zea mays. FRONTIERS IN PLANT SCIENCE 2017; 8:163. [PMID: 28261232 PMCID: PMC5309229 DOI: 10.3389/fpls.2017.00163] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/26/2017] [Indexed: 05/25/2023]
Abstract
Biogenesis of chloroplasts in higher plants is initiated from proplastids, and involves a series of processes by which a plastid able to perform photosynthesis, to synthesize amino acids, lipids, and phytohormones is formed. All plastid protein complexes are composed of subunits encoded by the nucleus and chloroplast genomes, which require a coordinated gene expression to produce the correct concentrations of organellar proteins and to maintain organelle function. To achieve this, hundreds of nucleus-encoded factors are imported into the chloroplast to control plastid gene expression. Among these factors, members of the Pentatricopeptide Repeat (PPR) containing protein family have emerged as key regulators of the organellar post-transcriptional processing. PPR proteins represent a large family in plants, and the extent to which PPR functions are conserved between dicots and monocots deserves evaluation, in light of differences in photosynthetic metabolism (C3 vs. C4) and localization of chloroplast biogenesis (mesophyll vs. bundle sheath cells). In this work we investigated the role played in the process of chloroplast biogenesis by At5g42310, a member of the Arabidopsis PPR family which we here refer to as AtCRP1 (Chloroplast RNA Processing 1), providing a comparison with the orthologous ZmCRP1 protein from Zea mays. Loss-of-function atcrp1 mutants are characterized by yellow-albinotic cotyledons and leaves owing to defects in the accumulation of subunits of the thylakoid protein complexes. As in the case of ZmCRP1, AtCRP1 associates with the 5' UTRs of both psaC and, albeit very weakly, petA transcripts, indicating that the role of CRP1 as regulator of chloroplast protein synthesis has been conserved between maize and Arabidopsis. AtCRP1 also interacts with the petB-petD intergenic region and is required for the generation of petB and petD monocistronic RNAs. A similar role has been also attributed to ZmCRP1, although the direct interaction of ZmCRP1 with the petB-petD intergenic region has never been reported, which could indicate that AtCRP1 and ZmCRP1 differ, in part, in their plastid RNA targets.
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Affiliation(s)
- Roberto Ferrari
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Luca Tadini
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Fabio Moratti
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
| | | | - Alex Costa
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Fabio Rossi
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli studi di MilanoMilano, Italy
| | - Monica Colombo
- Centro Ricerca e Innovazione, Fondazione Edmund MachSan Michele all’Adige, Italy
| | - Simona Masiero
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | | | - Paolo Pesaresi
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli studi di MilanoMilano, Italy
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Abstract
Numerous attempts have been made to identify and engineer sequence-specific RNA endonucleases, as these would allow for efficient RNA manipulation. However, no natural RNA endonuclease that recognizes RNA in a sequence-specific manner has been described to date. Here, we report that SUPPRESSOR OF THYLAKOID FORMATION 1 (SOT1), an Arabidopsis pentatricopeptide repeat (PPR) protein with a small MutS-related (SMR) domain, has RNA endonuclease activity. We show that the SMR moiety of SOT1 performs the endonucleolytic maturation of 23S and 4.5S rRNA through the PPR domain, specifically recognizing a 13-nucleotide RNA sequence in the 5' end of the chloroplast 23S-4.5S rRNA precursor. In addition, we successfully engineered the SOT1 protein with altered PPR motifs to recognize and cleave a predicted RNA substrate. Our findings point to SOT1 as an exciting tool for RNA manipulation.
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25
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Nishida I. 2016 Awards in the Journal of Plant Research. JOURNAL OF PLANT RESEARCH 2016; 129:1011-1012. [PMID: 27558684 DOI: 10.1007/s10265-016-0858-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Ikuo Nishida
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-Ku, Saitama, 338-8570, Japan.
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26
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Wang D, Liu H, Zhai G, Wang L, Shao J, Tao Y. OspTAC2 encodes a pentatricopeptide repeat protein and regulates rice chloroplast development. J Genet Genomics 2016; 43:601-608. [PMID: 27760723 DOI: 10.1016/j.jgg.2016.09.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 08/24/2016] [Accepted: 09/13/2016] [Indexed: 11/17/2022]
Abstract
Functional chloroplast generation depends on the precise coordination of gene expression between the plastid and the nucleus and is essential for plant growth and development. In this study, a rice (Oryza sativa) mutant that exhibited albino and seedling-lethal phenotypes was isolated from a60Co-irradiated rice population. The mutant gene was identified as an ortholog of the Arabidopsis plastid transcriptionally active chromosome protein 2 (pTAC2) gene, and the mutant strain was designated osptac2. Sequence and transcription analyses showed that OspTAC2 encodes a putative chloroplast protein consisting of 10 pentratricopeptide repeat (PPR) domains and a C-terminal small MutS-related (SMR) domain. Cytological observations via microscopy showed that the OspTAC2-green fluorescent fusion protein is localized in the chloroplasts. Transmission electron microscopy revealed that the chloroplast of the osptac2 mutant lacks an organized thylakoid membrane. The transcript levels of all investigated PEP (plastid-encoded RNA polymerase)-dependent genes were dramatically reduced in the osptac2 mutant, whereas the transcript levels of NEP (nuclear-encoded polymerase)-dependent genes were increased. These results suggest that OspTAC2 plays a critical role in chloroplast development and indicate that the molecular function of the OspTAC2 gene is conserved in rice and Arabidopsis.
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Affiliation(s)
- Dekai Wang
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Heqin Liu
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Guowei Zhai
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Liangsheng Wang
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853-1801, USA
| | - Jianfeng Shao
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yuezhi Tao
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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27
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Zhang L, Duan Z, Zhang J, Peng L. BIOGENESIS FACTOR REQUIRED FOR ATP SYNTHASE 3 Facilitates Assembly of the Chloroplast ATP Synthase Complex. PLANT PHYSIOLOGY 2016; 171:1291-306. [PMID: 27208269 PMCID: PMC4902607 DOI: 10.1104/pp.16.00248] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/12/2016] [Indexed: 05/04/2023]
Abstract
Thylakoid membrane-localized chloroplast ATP synthases use the proton motive force generated by photosynthetic electron transport to produce ATP from ADP. Although it is well known that the chloroplast ATP synthase is composed of more than 20 proteins with α3β3γ1ε1δ1I1II1III14IV1 stoichiometry, its biogenesis process is currently unclear. To unravel the molecular mechanisms underlying the biogenesis of chloroplast ATP synthase, we performed extensive screening for isolating ATP synthase mutants in Arabidopsis (Arabidopsis thaliana). In the recently identified bfa3 (biogenesis factors required for ATP synthase 3) mutant, the levels of chloroplast ATP synthase subunits were reduced to approximately 25% of wild-type levels. In vivo labeling analysis showed that assembly of the CF1 component of chloroplast ATP synthase was less efficient in bfa3 than in the wild type, indicating that BFA3 is required for CF1 assembly. BFA3 encodes a chloroplast stromal protein that is conserved in higher plants, green algae, and a few species of other eukaryotic algae, and specifically interacts with the CF1β subunit. The BFA3 binding site was mapped to a region in the catalytic site of CF1β. Several residues highly conserved in eukaryotic CF1β are crucial for the BFA3-CF1β interaction, suggesting a coevolutionary relationship between BFA3 and CF1β. BFA3 appears to function as a molecular chaperone that transiently associates with unassembled CF1β at its catalytic site and facilitates subsequent association with CF1α during assembly of the CF1 subcomplex of chloroplast ATP synthase.
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Affiliation(s)
- Lin Zhang
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China (L.Z., Z.D., J.Z., L.P.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (L.Z., Z.D.)
| | - Zhikun Duan
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China (L.Z., Z.D., J.Z., L.P.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (L.Z., Z.D.)
| | - Jiao Zhang
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China (L.Z., Z.D., J.Z., L.P.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (L.Z., Z.D.)
| | - Lianwei Peng
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China (L.Z., Z.D., J.Z., L.P.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (L.Z., Z.D.)
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28
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Zoschke R, Watkins KP, Miranda RG, Barkan A. The PPR-SMR protein PPR53 enhances the stability and translation of specific chloroplast RNAs in maize. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:594-606. [PMID: 26643268 PMCID: PMC4777676 DOI: 10.1111/tpj.13093] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/19/2015] [Accepted: 11/24/2015] [Indexed: 05/09/2023]
Abstract
Pentatricopeptide repeat (PPR) proteins are helical repeat proteins that bind RNA and influence gene expression in mitochondria and chloroplasts. Several PPR proteins in plants harbor a carboxy-terminal small-MutS-related (SMR) domain, but the functions of the SMR appendage are unknown. To address this issue, we studied a maize PPR-SMR protein denoted PPR53 (GRMZM2G438524), which is orthologous to the Arabidopsis protein SOT1 (AT5G46580). Null ppr53 alleles condition a chlorotic, seedling-lethal phenotype and a reduction in plastid ribosome content. Plastome-wide transcriptome and translatome analyses revealed strong defects in the expression of the ndhA and rrn23 genes, which were superimposed on secondary effects resulting from a decrease in plastid ribosome content. Transcripts with processed 5'-ends mapping approximately 70 nucleotides upstream of rrn23 and ndhA are absent in ppr53 mutants, and the translational efficiency of the residual ndhA mRNAs is reduced. Recombinant PPR53 binds with high affinity and specificity to the 5' proximal region of the PPR53-dependent 23S rRNA, suggesting that PPR53 protects this RNA via a barrier mechanism similar to that described for several PPR proteins lacking SMR motifs. However, recombinant PPR53 did not bind with high affinity to the ndhA 5' untranslated region, suggesting that PPR53's RNA-stabilization and translation-enhancing effects at the ndhA locus involve the participation of other factors.
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Affiliation(s)
- Reimo Zoschke
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | | | - Rafael G. Miranda
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
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29
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Wu W, Liu S, Ruwe H, Zhang D, Melonek J, Zhu Y, Hu X, Gusewski S, Yin P, Small ID, Howell KA, Huang J. SOT1, a pentatricopeptide repeat protein with a small MutS-related domain, is required for correct processing of plastid 23S-4.5S rRNA precursors in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:607-21. [PMID: 26800847 DOI: 10.1111/tpj.13126] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 01/12/2016] [Indexed: 05/22/2023]
Abstract
Ribosomal RNA processing is essential for plastid ribosome biogenesis, but is still poorly understood in higher plants. Here, we show that SUPPRESSOR OF THYLAKOID FORMATION1 (SOT1), a plastid-localized pentatricopeptide repeat (PPR) protein with a small MutS-related domain, is required for maturation of the 23S-4.5S rRNA dicistron. Loss of SOT1 function leads to slower chloroplast development, suppression of leaf variegation, and abnormal 23S and 4.5S processing. Predictions based on the PPR motif sequences identified the 5' end of the 23S-4.5S rRNA dicistronic precursor as a putative SOT1 binding site. This was confirmed by electrophoretic mobility shift assay, and by loss of the abundant small RNA 'footprint' associated with this site in sot1 mutants. We found that more than half of the 23S-4.5S rRNA dicistrons in sot1 mutants contain eroded and/or unprocessed 5' and 3' ends, and that the endonucleolytic cleavage product normally released from the 5' end of the precursor is absent in a sot1 null mutant. We postulate that SOT1 binding protects the 5' extremity of the 23S-4.5S rRNA dicistron from exonucleolytic attack, and favours formation of the RNA structure that allows endonucleolytic processing of its 5' and 3' ends.
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MESH Headings
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Base Sequence
- Binding Sites/genetics
- Blotting, Western
- Gene Expression Regulation, Plant
- Mutation
- Plants, Genetically Modified
- Plastids/genetics
- Plastids/metabolism
- Protein Binding
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Wenjuan Wu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sheng Liu
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Hannes Ruwe
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, 430070, China
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Yajuan Zhu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Xupeng Hu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sandra Gusewski
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ian D Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Centre of Excellence in Computational Systems Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Katharine A Howell
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Jirong Huang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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30
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Schöttler MA, Tóth SZ, Boulouis A, Kahlau S. Photosynthetic complex stoichiometry dynamics in higher plants: biogenesis, function, and turnover of ATP synthase and the cytochrome b6f complex. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2373-400. [PMID: 25540437 DOI: 10.1093/jxb/eru495] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During plant development and in response to fluctuating environmental conditions, large changes in leaf assimilation capacity and in the metabolic consumption of ATP and NADPH produced by the photosynthetic apparatus can occur. To minimize cytotoxic side reactions, such as the production of reactive oxygen species, photosynthetic electron transport needs to be adjusted to the metabolic demand. The cytochrome b6f complex and chloroplast ATP synthase form the predominant sites of photosynthetic flux control. Accordingly, both respond strongly to changing environmental conditions and metabolic states. Usually, their contents are strictly co-regulated. Thereby, the capacity for proton influx into the lumen, which is controlled by electron flux through the cytochrome b6f complex, is balanced with proton efflux through ATP synthase, which drives ATP synthesis. We discuss the environmental, systemic, and metabolic signals triggering the stoichiometry adjustments of ATP synthase and the cytochrome b6f complex. The contribution of transcriptional and post-transcriptional regulation of subunit synthesis, and the importance of auxiliary proteins required for complex assembly in achieving the stoichiometry adjustments is described. Finally, current knowledge on the stability and turnover of both complexes is summarized.
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Affiliation(s)
- Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Szilvia Z Tóth
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Alix Boulouis
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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31
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Manna S. An overview of pentatricopeptide repeat proteins and their applications. Biochimie 2015; 113:93-9. [PMID: 25882680 DOI: 10.1016/j.biochi.2015.04.004] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/03/2015] [Indexed: 01/24/2023]
Abstract
Pentatricopeptide repeat (PPR) proteins are a large family of modular RNA-binding proteins which mediate several aspects of gene expression primarily in organelles but also in the nucleus. These proteins facilitate processing, splicing, editing, stability and translation of RNAs. While major advances in PPR research have been achieved with plant PPR proteins, the significance of non-plant PPR proteins is becoming of increasing importance. PPR proteins are classified into different subclasses based on their domain architecture, which is often a reflection of their function. This review provides an overview of the significant findings regarding the functions, evolution and applications of PPR proteins. Horizontal gene transfer appears to have played a major role in the sporadic phylogenetic distribution of different PPR subclasses in both eukaryotes and prokaryotes. Additionally, the use of synthetic biology and protein engineering to create designer PPR proteins to control gene expression in vivo is discussed. This review also highlights some of the aspects of PPR research that require more attention particularly in non-plant organisms. This includes the lack of research into the recently discovered PPR-TGM subclass, which is not only the first PPR subclass absent from plants but present in economically and clinically-relevant pathogens. Investigation into the structure and function of PPR-TGM proteins in these pathogens presents a novel opportunity for the exploitation of PPR proteins as drug targets to prevent disease.
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Affiliation(s)
- Sam Manna
- Department of Microbiology, La Trobe University, Melbourne, Victoria, Australia.
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32
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Belcher S, Williams-Carrier R, Stiffler N, Barkan A. Large-scale genetic analysis of chloroplast biogenesis in maize. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1004-16. [PMID: 25725436 DOI: 10.1016/j.bbabio.2015.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/16/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND Chloroplast biogenesis involves a collaboration between several thousand nuclear genes and ~100 genes in the chloroplast. Many of the nuclear genes are of cyanobacterial ancestry and continue to perform their ancestral function. However, many others evolved subsequently and comprise a diverse set of proteins found specifically in photosynthetic eucaryotes. Genetic approaches have been key to the discovery of nuclear genes that participate in chloroplast biogenesis, especially those lacking close homologs outside the plant kingdom. SCOPE OF REVIEW This article summarizes contributions from a genetic resource in maize, the Photosynthetic Mutant Library (PML). The PML collection consists of ~2000 non-photosynthetic mutants induced by Mu transposons. We include a summary of mutant phenotypes for 20 previously unstudied maize genes, including genes encoding chloroplast ribosomal proteins, a PPR protein, tRNA synthetases, proteins involved in plastid transcription, a putative ribosome assembly factor, a chaperonin 60 isoform, and a NifU-domain protein required for Photosystem I biogenesis. MAJOR CONCLUSIONS Insertions in 94 maize genes have been linked thus far to visible and molecular phenotypes with the PML collection. The spectrum of chloroplast biogenesis genes that have been genetically characterized in maize is discussed in the context of related efforts in other organisms. This comparison shows how distinct organismal attributes facilitate the discovery of different gene classes, and reveals examples of functional divergence between monocot and dicot plants. GENERAL SIGNIFICANCE These findings elucidate the biology of an organelle whose activities are fundamental to agriculture and the biosphere. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Susan Belcher
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | | | - Nicholas Stiffler
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
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33
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Rühle T, Leister D. Assembly of F1F0-ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:849-60. [PMID: 25667968 DOI: 10.1016/j.bbabio.2015.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 12/31/2022]
Abstract
F1F0-ATP synthases are multimeric protein complexes and common prerequisites for their correct assembly are (i) provision of subunits in appropriate relative amounts, (ii) coordination of membrane insertion and (iii) avoidance of assembly intermediates that uncouple the proton gradient or wastefully hydrolyse ATP. Accessory factors facilitate these goals and assembly occurs in a modular fashion. Subcomplexes common to bacteria and mitochondria, but in part still elusive in chloroplasts, include a soluble F1 intermediate, a membrane-intrinsic, oligomeric c-ring, and a membrane-embedded subcomplex composed of stator subunits and subunit a. The final assembly step is thought to involve association of the preformed F1-c10-14 with the ab2 module (or the ab8-stator module in mitochondria)--mediated by binding of subunit δ in bacteria or OSCP in mitochondria, respectively. Despite the common evolutionary origin of F1F0-ATP synthases, the set of auxiliary factors required for their assembly in bacteria, mitochondria and chloroplasts shows clear signs of evolutionary divergence. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Thilo Rühle
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
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34
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Gully BS, Shah KR, Lee M, Shearston K, Smith NM, Sadowska A, Blythe AJ, Bernath-Levin K, Stanley WA, Small ID, Bond CS. The design and structural characterization of a synthetic pentatricopeptide repeat protein. ACTA ACUST UNITED AC 2015; 71:196-208. [PMID: 25664731 DOI: 10.1107/s1399004714024869] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 11/12/2014] [Indexed: 11/10/2022]
Abstract
Proteins of the pentatricopeptide repeat (PPR) superfamily are characterized by tandem arrays of a degenerate 35-amino-acid α-hairpin motif. PPR proteins are typically single-stranded RNA-binding proteins with essential roles in organelle biogenesis, RNA editing and mRNA maturation. A modular, predictable code for sequence-specific binding of RNA by PPR proteins has recently been revealed, which opens the door to the de novo design of bespoke proteins with specific RNA targets, with widespread biotechnological potential. Here, the design and production of a synthetic PPR protein based on a consensus sequence and the determination of its crystal structure to 2.2 Å resolution are described. The crystal structure displays helical disorder, resulting in electron density representing an infinite superhelical PPR protein. A structural comparison with related tetratricopeptide repeat (TPR) proteins, and with native PPR proteins, reveals key roles for conserved residues in directing the structure and function of PPR proteins. The designed proteins have high solubility and thermal stability, and can form long tracts of PPR repeats. Thus, consensus-sequence synthetic PPR proteins could provide a suitable backbone for the design of bespoke RNA-binding proteins with the potential for high specificity.
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Affiliation(s)
- Benjamin S Gully
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Kunal R Shah
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Mihwa Lee
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Kate Shearston
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nicole M Smith
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Agata Sadowska
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Amanda J Blythe
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Kalia Bernath-Levin
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Will A Stanley
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ian D Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Charles S Bond
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
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35
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Gully BS, Cowieson N, Stanley WA, Shearston K, Small ID, Barkan A, Bond CS. The solution structure of the pentatricopeptide repeat protein PPR10 upon binding atpH RNA. Nucleic Acids Res 2015; 43:1918-26. [PMID: 25609698 PMCID: PMC4330388 DOI: 10.1093/nar/gkv027] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The pentatricopeptide repeat (PPR) protein family is a large family of RNA-binding proteins that is characterized by tandem arrays of a degenerate 35-amino-acid motif which form an α-solenoid structure. PPR proteins influence the editing, splicing, translation and stability of specific RNAs in mitochondria and chloroplasts ZEA MAYS: PPR10 is amongst the best studied PPR proteins, where sequence-specific binding to two RNA transcripts, ATPH: and PSAJ, HAS BEEN DEMONSTRATED TO FOLLOW: a recognition code where the identity of two amino acids per repeat determines the base-specificity. A recently solved ZmPPR10: PSAJ: complex crystal structure suggested a homodimeric complex with considerably fewer sequence-specific protein-RNA contacts than inferred PREVIOUSLY: Here we describe the solution structure of the ZmPPR10: ATPH: complex using size-exclusion chromatography-coupled synchrotron small-angle X-ray scattering (SEC-SY-SAXS). Our results support prior evidence that PPR10 binds RNA as a monomer, and that it does so in a manner that is commensurate with a canonical and predictable RNA-binding mode across much of the RNA-protein interface.
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Affiliation(s)
- Benjamin S Gully
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nathan Cowieson
- SAXSWAXS beamline, Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria, Australia
| | - Will A Stanley
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Kate Shearston
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ian D Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Charles S Bond
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
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36
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Abstract
Pentatricopeptide repeat (PPR) proteins constitute one of the largest protein families in land plants, with more than 400 members in most species. Over the past decade, much has been learned about the molecular functions of these proteins, where they act in the cell, and what physiological roles they play during plant growth and development. A typical PPR protein is targeted to mitochondria or chloroplasts, binds one or several organellar transcripts, and influences their expression by altering RNA sequence, turnover, processing, or translation. Their combined action has profound effects on organelle biogenesis and function and, consequently, on photosynthesis, respiration, plant development, and environmental responses. Recent breakthroughs in understanding how PPR proteins recognize RNA sequences through modular base-specific contacts will help match proteins to potential binding sites and provide a pathway toward designing synthetic RNA-binding proteins aimed at desired targets.
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Affiliation(s)
- Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97405;
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37
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Manna S, Barth C. Identification of a novel pentatricopeptide repeat subfamily with a C-terminal domain of bacterial origin acquired via ancient horizontal gene transfer. BMC Res Notes 2013; 6:525. [PMID: 24321137 PMCID: PMC4029402 DOI: 10.1186/1756-0500-6-525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/29/2013] [Indexed: 11/10/2022] Open
Abstract
Background Pentatricopeptide repeat (PPR) proteins are a large family of sequence-specific RNA binding proteins involved in organelle RNA metabolism. Very little is known about the origin and evolution of these proteins, particularly outside of plants. Here, we report the identification of a novel subfamily of PPR proteins not found in plants and explore their evolution. Results We identified a novel subfamily of PPR proteins, which all contain a C-terminal tRNA guanine methyltransferase (TGM) domain, suggesting a predicted function not previously associated with PPR proteins. This group of proteins, which we have named the PPR-TGM subfamily, is found in distantly related eukaryotic lineages including cellular slime moulds, entamoebae, algae and diatoms, but appears to be the first PPR subfamily absent from plants. Each PPR-TGM protein identified is predicted to have different subcellular locations, thus we propose that these proteins have roles in tRNA metabolism in all subcellular locations, not just organelles. We demonstrate that the TGM domain is not only similar to bacterial TGM proteins, but that it is most similar to chlamydial TGMs in particular, despite the absence of PPR proteins in bacteria. Based on our data, we postulate that this subfamily of PPR proteins evolved from a TGM-encoding gene of a member of the Chlamydiae, which was obtained via ancient prokaryote-to-eukaryote horizontal gene transfer. Following its acquisition, the N-terminus of the encoded TGM protein must have been extended to include PPR motifs, possibly to confer additional functions to the protein, giving rise to the PPR-TGM subfamily. Conclusions The identification of a unique PPR subfamily which originated from the Chlamydiae group of bacteria offers novel insight into the origin and evolution of PPR proteins not previously considered. It also provides further understanding into their roles in non-organellar RNA metabolism.
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Affiliation(s)
| | - Christian Barth
- Department of Microbiology, La Trobe University, Melbourne, VIC 3086, Australia.
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38
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Abstract
Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome.
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Affiliation(s)
- Nicolas J Tourasse
- UMR 7141 CNRS/UPMC; Institut de Biologie Physico-Chimique; F-75005 Paris, France
| | - Yves Choquet
- UMR 7141 CNRS/UPMC; Institut de Biologie Physico-Chimique; F-75005 Paris, France
| | - Olivier Vallon
- UMR 7141 CNRS/UPMC; Institut de Biologie Physico-Chimique; F-75005 Paris, France
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39
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Liu S, Melonek J, Boykin LM, Small I, Howell KA. PPR-SMRs: ancient proteins with enigmatic functions. RNA Biol 2013; 10:1501-10. [PMID: 24004908 PMCID: PMC3858433 DOI: 10.4161/rna.26172] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A small subset of the large pentatricopeptide repeat (PPR) protein family in higher plants contain a C-terminal small MutS-related (SMR) domain. Although few in number, they figure prominently in the chloroplast biogenesis and retrograde signaling literature due to their striking mutant phenotypes. In this review, we summarize current knowledge of PPR-SMR proteins focusing on Arabidopsis and maize proteomic and mutant studies. We also examine their occurrence in other organisms and have determined by phylogenetic analysis that, while they are limited to species that contain chloroplasts, their presence in algae and early branching land plant lineages indicates that the coupling of PPR motifs and an SMR domain into a single protein occurred early in the evolution of the Viridiplantae clade. In addition, we discuss their possible function and have examined conservation between SMR domains from Arabidopsis PPR proteins with those from other species that have been shown to possess endonucleolytic activity.
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Affiliation(s)
- Sheng Liu
- Australian Research Council Centre of Excellence in Plant Energy Biology; The University of Western Australia; Crawley, WA Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology; The University of Western Australia; Crawley, WA Australia
| | - Laura M Boykin
- Centre of Excellence in Computational Systems Biology; The University of Western Australia; Crawley, WA Australia
| | - Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology; The University of Western Australia; Crawley, WA Australia; Centre of Excellence in Computational Systems Biology; The University of Western Australia; Crawley, WA Australia
| | - Katharine A Howell
- Australian Research Council Centre of Excellence in Plant Energy Biology; The University of Western Australia; Crawley, WA Australia
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