1
|
Schwestka J, Zeh L, Tschofen M, Schubert F, Arcalis E, Esteve-Gasent M, Pedrazzini E, Vitale A, Stoger E. Generation of multi-layered protein bodies in N. benthamiana for the encapsulation of vaccine antigens. FRONTIERS IN PLANT SCIENCE 2023; 14:1109270. [PMID: 36733717 PMCID: PMC9887037 DOI: 10.3389/fpls.2023.1109270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 01/02/2023] [Indexed: 06/18/2023]
Abstract
The ability of plants to assemble particulate structures such as virus-like particles and protein storage organelles allows the direct bioencapsulation of recombinant proteins during the manufacturing process, which holds promise for the development of new drug delivery vehicles. Storage organelles found in plants such as protein bodies (PBs) have been successfully used as tools for accumulation and encapsulation of recombinant proteins. The fusion of sequences derived from 27-kDa-γ-zein, a major storage protein of maize, with a protein of interest leads to the incorporation of the chimeric protein into the stable and protected environment inside newly induced PBs. While this procedure has proven successful for several, but not all recombinant proteins, the aim of this study was to refine the technology by using a combination of PB-forming proteins, thereby generating multi-layered protein assemblies in N. benthamiana. We used fluorescent proteins to demonstrate that up to three proteinaceous components can be incorporated into different layers. In addition to 27-kDa-γ-zein, which is essential for PB initiation, 16-kDa-γ-zein was identified as a key element to promote the incorporation of a third zein-component into the core of the PBs. We show that a vaccine antigen could be incorporated into the matrix of multi-layered PBs, and the protein microparticles were characterized by confocal and electron microscopy as well as flow cytometry. In future, this approach will enable the generation of designer PBs that serve as drug carriers and integrate multiple components that can be functionalized in different ways.
Collapse
Affiliation(s)
- Jennifer Schwestka
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Lukas Zeh
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Marc Tschofen
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Fabian Schubert
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Elsa Arcalis
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Maria Esteve-Gasent
- Department of Veterinary Pathobiology, College of Veterinary Medicine, College Station, TX, United States
| | - Emanuela Pedrazzini
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche (CNR), Milano, Italy
| | - Alessandro Vitale
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche (CNR), Milano, Italy
| | - Eva Stoger
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| |
Collapse
|
2
|
Arcalís E, Hörmann-Dietrich U, Zeh L, Stoger E. 3D Electron Microscopy Gives a Clue: Maize Zein Bodies Bud From Central Areas of ER Sheets. FRONTIERS IN PLANT SCIENCE 2020; 11:809. [PMID: 32595683 PMCID: PMC7301906 DOI: 10.3389/fpls.2020.00809] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/19/2020] [Indexed: 05/27/2023]
Abstract
Zeins are the main storage proteins in maize seed endosperm, and the onset of zein synthesis in young seeds challenges the endomembrane system and results in the formation of storage organelles. Even though zeins lack a conventional endoplasmic reticulum (ER) retention signal, they accumulate within the ER and assemble in conspicuous ER-derived protein bodies (PBs) stabilized by disulfide bridge formation and hydrophobic interaction between zein chains. Zein body formation during seed development has been extensively studied, as well as the mechanisms that lead to the initiation of PBs. However, the exact course of the PB formation process and the spatial relationship with the ER remain unclear. The development of serial block face scanning electron microscopy (SBF-SEM) techniques that allow three-dimensional imaging combined with the high resolution of electron microscopy provides new perspectives on the study of the plant endomembrane system. Here, we demonstrate that (i) the ER of maize seeds is mainly formed by massive sheets and (ii) PBs are not budding from tubules or the edge of sheets, but protrude from the entire surface of the ER sheet.
Collapse
Affiliation(s)
| | | | | | - Eva Stoger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| |
Collapse
|
3
|
Kim WS, Krishnan HB. Impact of co-expression of maize 11 and 18 kDa δ-zeins and 27 kDa γ-zein in transgenic soybeans on protein body structure and sulfur amino acid content. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 280:340-347. [PMID: 30824013 DOI: 10.1016/j.plantsci.2018.12.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 05/27/2023]
Abstract
The methionine-rich seed storage proteins of maize have been expressed in transgenic plants as a means to improve the overall sulfur amino acid content of seed. Previous attempts to increase the sulfur amino acid content of soybean seeds by this approach has met with limited success. It has been shown co-expression of different class of zeins can result in their stable accumulation in transgenic plants. In this study, conventional crosses between transgenic plants individually expressing 11, 18 kDa δ-zeins and 27 kDa γ-zein were made to obtain plants that simultaneously express both the δ-zein and γ-zein. Transmission electron microscopic observation of thin-sections of transgenic soybean seeds revealed that the zeins accumulated in ER-derived protein bodies (PBs) which were found sparsely scattered in cytoplasm. The size of these PBs varied from 0.2 to 0.6 μm in soybean plants individually expressing 11, 18 kDa δ-zeins and 27 kDa γ-zein. In contrast, soybeans co-expressing the 18 kDa δ-zein and 27 kDa γ-zein the PBs was 3-4 times larger. Electron microscopic observation also revealed the sequestration of PBs inside the vacuoles where they could be subjected to degradation by vacuolar proteases. Amino acid analysis of transgenic soybean individually expressing 11, 18 kDa δ-zeins and 27 kDa γ-zein revealed only a minimal increase in the overall methionine content compared to the wild-type. In contrast, plants co-expressing 18 kDa δ-zein and 27 kDa γ-zein showed a significant increase (27%) in the methionine content compared to the control seeds.
Collapse
Affiliation(s)
- Won-Seok Kim
- Plant Science Division, University of Missouri, Columbia, MO 65211, United States
| | - Hari B Krishnan
- Plant Science Division, University of Missouri, Columbia, MO 65211, United States; Plant Genetics Research, USDA-Agricultural Research Service, Columbia, MO 65211, United States.
| |
Collapse
|
4
|
Joshi JB, Geetha S, Singh B, Kumar KK, Kokiladevi E, Arul L, Balasubramanian P, Sudhakar D. A maize α-zein promoter drives an endosperm-specific expression of transgene in rice. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2015; 21:35-42. [PMID: 25649529 PMCID: PMC4312335 DOI: 10.1007/s12298-014-0268-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
An alpha-zein promoter isolated from maize containing P-box, E motif sequence TGTAAAGT, opaque-2 box and TATA box was studied for its tissue-specific expression in rice. A 1,098 bp promoter region of alpha-zein gene, fused to the upstream of gusA reporter gene was used for transforming rice immature embryos (ASD 16 or IR 64) via the particle bombardment-mediated method. PCR analysis of putative transformants demonstrated the presence of transgenes (the zein promoter, gusA and hpt). Nineteen out of 37 and two out of five events generated from ASD 16 and IR 64 were found to be GUS-positive. A histological staining analysis performed on sections of mature T1 seeds revealed that the GUS expression was limited to the endosperm and not to the pericarp or the endothelial region. GUS expression was observed only in the following seed development stages : milky (14-15 DAF), soft dough (17-18 DAF), hard dough (20-23 DAF), and mature stages (28-30 DAF) of zein-gusA transformed (T0) plants. On the contrary a constitutive expression of GUS was evident in CaMV35S-gusA plants. PCR and Southern blotting analyses on T1 plants demonstrated a stable integration and inheritance of transgene in the subsequent T1 generation. GUS assay on T2 seeds revealed that the expression of gusA gene driven by alpha-zein promoter was stable and tissue-specific over two generations. Results suggest that this alpha-zein promoter could serve as an alternative promoter to drive endosperm-specific expression of transgenes in rice and other cereal transformation experiments.
Collapse
Affiliation(s)
- J. Beslin Joshi
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - S. Geetha
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - Birla Singh
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - K. K. Kumar
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - E. Kokiladevi
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - L. Arul
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - P. Balasubramanian
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| | - D. Sudhakar
- Department of Plant Molecular Biology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641 003 India
| |
Collapse
|
5
|
Arcalis E, Ibl V, Peters J, Melnik S, Stoger E. The dynamic behavior of storage organelles in developing cereal seeds and its impact on the production of recombinant proteins. FRONTIERS IN PLANT SCIENCE 2014; 5:439. [PMID: 25232360 PMCID: PMC4153030 DOI: 10.3389/fpls.2014.00439] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 08/15/2014] [Indexed: 05/22/2023]
Abstract
Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins, which are ultimately deposited either within protein bodies derived from the endoplasmic reticulum, or in protein storage vacuoles (PSVs). During seed maturation endosperm cells undergo a rapid sequence of developmental changes, including extensive reorganization and rearrangement of the endomembrane system and protein transport via several developmentally regulated trafficking routes. Storage organelles have been characterized in great detail by the histochemical analysis of fixed immature tissue samples. More recently, in vivo imaging and the use of tonoplast markers and fluorescent organelle tracers have provided further insight into the dynamic morphology of PSVs in different cell layers of the developing endosperm. This is relevant for biotechnological applications in the area of molecular farming because seed storage organelles in different cereal crops offer alternative subcellular destinations for the deposition of recombinant proteins that can reduce proteolytic degradation, allow control over glycan structures and increase the efficacy of oral delivery. We discuss how the specialized architecture and developmental changes of the endomembrane system in endosperm cells may influence the subcellular fate and post-translational modification of recombinant glycoproteins in different cereal species.
Collapse
Affiliation(s)
| | | | | | | | - Eva Stoger
- *Correspondence: Eva Stoger, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria e-mail:
| |
Collapse
|
6
|
Peters J, Sabalza M, Ramessar K, Christou P, Capell T, Stöger E, Arcalís E. Efficient recovery of recombinant proteins from cereal endosperm is affected by interaction with endogenous storage proteins. Biotechnol J 2013; 8:1203-12. [PMID: 23960004 DOI: 10.1002/biot.201300068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/02/2013] [Accepted: 08/16/2013] [Indexed: 01/02/2023]
Abstract
Cereal seeds are versatile platforms for the production of recombinant proteins because they provide a stable environment for protein accumulation. Endogenous seed storage proteins, however, include several prolamin-type polypeptides that aggregate and crosslink via intermolecular disulfide bridges, which could potentially interact with multimeric recombinant proteins such as antibodies, which assemble in the same manner. We investigated this possibility by sequentially extracting a human antibody expressed in maize endosperm, followed by precipitation in vitro with zein. We provide evidence that a significant proportion of the antibody pool interacts with zein and therefore cannot be extracted using non-reducing buffers. Immunolocalization experiments demonstrated that antibodies targeted for secretion were instead retained within zein bodies because of such covalent interactions. Our findings suggest that the production of soluble recombinant antibodies in maize could be enhanced by eliminating or minimizing interactions with endogenous storage proteins.
Collapse
Affiliation(s)
- Jenny Peters
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | | | | | | | | | | |
Collapse
|
7
|
Saito Y, Shigemitsu T, Yamasaki R, Sasou A, Goto F, Kishida K, Kuroda M, Tanaka K, Morita S, Satoh S, Masumura T. Formation mechanism of the internal structure of type I protein bodies in rice endosperm: relationship between the localization of prolamin species and the expression of individual genes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:1043-55. [PMID: 22348505 DOI: 10.1111/j.1365-313x.2012.04947.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rice prolamins, a group of seed storage proteins, are synthesized on the rough endoplasmic reticulum (ER) and form type I protein bodies (PB-Is) in endosperm cells. Rice prolamins are encoded by a multigene family. In this study, the spatial accumulation patterns of various prolamin species in rice endosperm cells were investigated to determine the mechanism of formation of the internal structure of PB-Is. Immunofluorescence microscopic analysis of mature endosperm cells showed that the 10 kDa prolamin is mainly localized in the core of the PB-Is, the 13b prolamin is localized in the inner layer surrounding the core and the outermost layer, and the 13a and 16 kDa prolamins are localized in the middle layer. Real-time RT-PCR analysis showed that expression of the mRNA for 10 kDa prolamin precedes expression of 13a, 13b-1 and 16 kDa prolamin in the developing stages. mRNA expression for 13b-2 prolamin occurred after that of the other prolamin species. Immunoelectron microscopy of developing seeds showed that the 10 kDa prolamin polypeptide initially accumulates in the ER, and then 13b, 13a, 16 kDa and 13b prolamins are stacked in layers within the ER. Studies with transgenic rice seeds expressing prolamin-GFP fusion proteins under the control of native and constitutive promoters indicated that the temporal expression pattern of prolamin genes influenced the localization of prolamin proteins within the PB-Is. These findings indicate that the control of gene expression of prolamin species contributes to the internal structure of PB-Is.
Collapse
Affiliation(s)
- Yuhi Saito
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Ibl V, Stoger E. The formation, function and fate of protein storage compartments in seeds. PROTOPLASMA 2012; 249:379-92. [PMID: 21614590 DOI: 10.1007/s00709-011-0288-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 05/12/2011] [Indexed: 05/07/2023]
Abstract
Seed storage proteins (SSPs) have been studied for more than 250 years because of their nutritional value and their impact on the use of grain in food processing. More recently, the use of seeds for the production of recombinant proteins has rekindled interest in the behavior of SSPs and the question how they are able to accumulate as stable storage reserves. Seed cells produce vast amounts of SSPs with different subcellular destinations creating an enormous logistic challenge for the endomembrane system. Seed cells contain several different storage organelles including the complex and dynamic protein storage vacuoles (PSVs) and other protein bodies (PBs) derived from the endoplasmic reticulum (ER). Storage proteins destined for the PSV may pass through or bypass the Golgi, using different vesicles that follow different routes through the cell. In addition, trafficking may depend on the plant species, tissue and developmental stage, showing that the endomembrane system is capable of massive reorganization. Some SSPs contain sorting signals or interact with membranes or with other proteins en route in order to reach their destination. The ability of SSPs to form aggregates is particularly important in the formation or ER-derived PBs, a mechanism that occurs naturally in response to overloading with proteins that cannot be transported and that can be used to induce artificial storage bodies in vegetative tissues. In this review, we summarize recent findings that provide insight into the formation, function, and fate of storage organelles and describe tools that can be used to study them.
Collapse
Affiliation(s)
- Verena Ibl
- Department for Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | | |
Collapse
|
9
|
da Silva LS, Jung R, Zhao ZY, Glassman K, Taylor J, Taylor JR. Effect of suppressing the synthesis of different kafirin sub-classes on grain endosperm texture, protein body structure and protein nutritional quality in improved sorghum lines. J Cereal Sci 2011. [DOI: 10.1016/j.jcs.2011.04.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
10
|
Reyes FC, Chung T, Holding D, Jung R, Vierstra R, Otegui MS. Delivery of prolamins to the protein storage vacuole in maize aleurone cells. THE PLANT CELL 2011; 23:769-84. [PMID: 21343414 PMCID: PMC3077793 DOI: 10.1105/tpc.110.082156] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 01/28/2011] [Accepted: 02/12/2011] [Indexed: 05/18/2023]
Abstract
Zeins, the prolamin storage proteins found in maize (Zea mays), accumulate in accretions called protein bodies inside the endoplasmic reticulum (ER) of starchy endosperm cells. We found that genes encoding zeins, α-globulin, and legumin-1 are transcribed not only in the starchy endosperm but also in aleurone cells. Unlike the starchy endosperm, aleurone cells accumulate these storage proteins inside protein storage vacuoles (PSVs) instead of the ER. Aleurone PSVs contain zein-rich protein inclusions, a matrix, and a large system of intravacuolar membranes. After being assembled in the ER, zeins are delivered to the aleurone PSVs in atypical prevacuolar compartments that seem to arise at least partially by autophagy and consist of multilayered membranes and engulfed cytoplasmic material. The zein-containing prevacuolar compartments are neither surrounded by a double membrane nor decorated by AUTOPHAGY RELATED8 protein, suggesting that they are not typical autophagosomes. The PSV matrix contains glycoproteins that are trafficked through a Golgi-multivesicular body (MVB) pathway. MVBs likely fuse with the multilayered, autophagic compartments before merging with the PSV. The presence of similar PSVs also containing prolamins and large systems of intravacuolar membranes in wheat (Triticum aestivum) and barley (Hordeum vulgare) starchy endosperm suggests that this trafficking mechanism may be common among cereals.
Collapse
Affiliation(s)
| | - Taijoon Chung
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - David Holding
- Department of Agronomy and Horticulture, Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68588-0665
| | - Rudolf Jung
- Pioneer Hi-Bred International, a DuPont Company, Johnston, Iowa 50131
| | - Richard Vierstra
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Marisa S. Otegui
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706
- Address correspondence to
| |
Collapse
|
11
|
Kawakatsu T, Takaiwa F. Cereal seed storage protein synthesis: fundamental processes for recombinant protein production in cereal grains. PLANT BIOTECHNOLOGY JOURNAL 2010; 8:939-53. [PMID: 20731787 DOI: 10.1111/j.1467-7652.2010.00559.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cereal seeds provide an ideal production platform for high-value products such as pharmaceuticals and industrial materials because seeds have ample and stable space for the deposition of recombinant products without loss of activity at room. Seed storage proteins (SSPs) are predominantly synthesized and stably accumulated in maturing endosperm tissue. Therefore, understanding the molecular mechanisms regulating SSP expression and accumulation is expected to provide valuable information for producing higher amounts of recombinant products. SSP levels are regulated by several steps at the transcriptional (promoters, transcription factors), translational and post-translational levels (modification, processing trafficking, and deposition). Our objective is to develop a seed production platform capable of producing very high yields of recombinant product. Towards this goal, we review here the individual regulatory steps controlling SSP synthesis and accumulation.
Collapse
Affiliation(s)
- Taiji Kawakatsu
- Transgenic Crop Research & Development Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | | |
Collapse
|
12
|
Wu Y, Messing J. RNA interference-mediated change in protein body morphology and seed opacity through loss of different zein proteins. PLANT PHYSIOLOGY 2010; 153:337-47. [PMID: 20237020 PMCID: PMC2862413 DOI: 10.1104/pp.110.154690] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 03/15/2010] [Indexed: 05/19/2023]
Abstract
Opaque or nonvitreous phenotypes relate to the seed architecture of maize (Zea mays) and are linked to loci that control the accumulation and proper deposition of storage proteins, called zeins, into specialized organelles in the endosperm, called protein bodies. However, in the absence of null mutants of each type of zein (i.e. alpha, beta, gamma, and delta), the molecular contribution of these proteins to seed architecture remains unclear. Here, a double null mutant for the delta-zeins, the 22-kD alpha-zein, the beta-zein, and the gamma-zein RNA interference (RNAi; designated as z1CRNAi, betaRNAi, and gammaRNAi, respectively) and their combinations have been examined. While the delta-zein double null mutant had negligible effects on protein body formation, the betaRNAi and gammaRNAi alone only cause slight changes. Substantial loss of the 22-kD alpha-zeins by z1CRNAi resulted in protein body budding structures, indicating that a sufficient amount of the 22-kD zeins is necessary for maintenance of a normal protein body shape. Among different mutant combinations, only the combined betaRNAi and gammaRNAi resulted in drastic morphological changes, while other combinations did not. Overexpression of alpha-kafirins, the homologues of the maize 22-kD alpha-zeins in sorghum (Sorghum bicolor), in the beta/gammaRNAi mutant failed to offset the morphological alterations, indicating that beta- and gamma-zeins have redundant and unique functions in the stabilization of protein bodies. Indeed, opacity of the beta/gammaRNAi mutant was caused by incomplete embedding of the starch granules rather than by reducing the vitreous zone.
Collapse
|
13
|
Washida H, Sugino A, Kaneko S, Crofts N, Sakulsingharoj C, Kim D, Choi SB, Hamada S, Ogawa M, Wang C, Esen A, Higgins TJV, Okita TW. Identification of cis-localization elements of the maize 10-kDa delta-zein and their use in targeting RNAs to specific cortical endoplasmic reticulum subdomains. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:146-155. [PMID: 19508424 DOI: 10.1111/j.1365-313x.2009.03944.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The RNAs for the storage proteins of rice (Oryza sativa), prolamines and glutelins, which are stored as inclusions in the lumen of the endoplasmic reticulum (ER) and storage vacuoles, respectively, are targeted by specific cis-localization elements to distinct subdomains of the cortical ER. Glutelin RNA has one or more cis-localization elements (zip codes) at the 3' end of the RNA, whereas prolamine has two cis-elements; one located in the 5' end of the coding sequence and a second residing in the 3'-untranslated region (UTR). We had earlier demonstrated that the RNAs for the maize zeins ('prolamine' class) are localized to the spherical protein body ER (PB-ER) in developing maize endosperm. As the PB-ER localization of the 10-kDa delta-zein RNA is maintained in developing rice seeds, we determined the number and proximate location of their cis-localization elements by expressing GFP fusions containing various zein RNA sequences in transgenic rice and analyzing their spatial distribution on the cortical ER by in situ RT-PCR and confocal microscopy. Four putative cis-localization elements were identified; three in the coding sequences and one in the 3'-UTR. Two of these zip codes are required for restricted localization to the PB-ER. Using RNA targeting determinants we show, by mis-targeting the storage protein RNAs from their normal destination on the cortical ER, that the coded proteins are redirected from their normal site of deposition. Targeting of RNA to distinct cortical ER subdomains may be the underlying basis for the variable use of the ER lumen or storage vacuole as the final storage deposition site of storage proteins among flowering plant species.
Collapse
Affiliation(s)
- Haruhiko Washida
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Saito Y, Kishida K, Takata K, Takahashi H, Shimada T, Tanaka K, Morita S, Satoh S, Masumura T. A green fluorescent protein fused to rice prolamin forms protein body-like structures in transgenic rice. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:615-27. [PMID: 19129168 PMCID: PMC2651459 DOI: 10.1093/jxb/ern311] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 10/22/2008] [Accepted: 11/10/2008] [Indexed: 05/19/2023]
Abstract
Prolamins, a group of rice (Oryza sativa) seed storage proteins, are synthesized on the rough endoplasmic reticulum (ER) and deposited in ER-derived type I protein bodies (PB-Is) in rice endosperm cells. The accumulation mechanism of prolamins, which do not possess the well-known ER retention signal, remains unclear. In order to elucidate whether the accumulation of prolamin in the ER requires seed-specific factors, the subcellular localization of the constitutively expressed green fluorescent protein fused to prolamin (prolamin-GFP) was examined in seeds, leaves, and roots of transgenic rice plants. The prolamin-GFP fusion proteins accumulated not only in the seeds but also in the leaves and roots. Microscopic observation of GFP fluorescence and immunocytochemical analysis revealed that prolamin-GFP fusion proteins specifically accumulated in PB-Is in the endosperm, whereas they were deposited in the electron-dense structures in the leaves and roots. The ER chaperone BiP was detected in the structures in the leaves and roots. The results show that the aggregation of prolamin-GFP fusion proteins does not depend on the tissues, suggesting that the prolamin-GFP fusion proteins accumulate in the ER by forming into aggregates. The findings bear out the importance of the assembly of prolamin molecules and the interaction of prolamin with BiP in the formation of ER-derived PBs.
Collapse
Affiliation(s)
- Yuhi Saito
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Koichi Kishida
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Kenji Takata
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Hideyuki Takahashi
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Takeaki Shimada
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Kunisuke Tanaka
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
| | - Shigeto Morita
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
- Kyoto Prefectural Institute of Agricultural Biotechnology, Kitainayazuma, Seika-cho, Soraku-gun, Kyoto 619-0244, Japan
| | - Shigeru Satoh
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
- Kyoto Prefectural Institute of Agricultural Biotechnology, Kitainayazuma, Seika-cho, Soraku-gun, Kyoto 619-0244, Japan
| | - Takehiro Masumura
- Laboratory of Genetic Engineering, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan
- Kyoto Prefectural Institute of Agricultural Biotechnology, Kitainayazuma, Seika-cho, Soraku-gun, Kyoto 619-0244, Japan
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
15
|
Holding DR, Otegui MS, Li B, Meeley RB, Dam T, Hunter BG, Jung R, Larkins BA. The maize floury1 gene encodes a novel endoplasmic reticulum protein involved in zein protein body formation. THE PLANT CELL 2007; 19:2569-82. [PMID: 17693529 PMCID: PMC2002605 DOI: 10.1105/tpc.107.053538] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The maize (Zea mays) floury1 (fl1) mutant was first reported almost 100 years ago, but its molecular identity has remained unknown. We report the cloning of Fl1, which encodes a novel zein protein body membrane protein with three predicted transmembrane domains and a C-terminal plant-specific domain of unknown function (DUF593). In wild-type endosperm, the FL1 protein accumulates at a high level during the period of zein synthesis and protein body development and declines to a low level at kernel maturity. Immunogold labeling showed that FL1 resides in the endoplasmic reticulum surrounding the protein body. Zein protein bodies in fl1 mutants are of normal size, shape, and abundance. However, mutant protein bodies ectopically accumulate 22-kD alpha-zeins in the gamma-zein-rich periphery and center of the core, rather than their normal discrete location in a ring at outer edge of the core. The 19-kD alpha-zein is uniformly distributed throughout the core in wild-type protein bodies, and this distribution is unaffected in fl1 mutants. Pairwise yeast two-hybrid experiments showed that FL1 DUF593 interacts with the 22-kD alpha-zein. Results of these studies suggest that FL1 participates in protein body formation by facilitating the localization of 22-kD alpha-zein and that this is essential for the formation of vitreous endosperm.
Collapse
Affiliation(s)
- David R Holding
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, 85721, USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Washida H, Crofts AJ, Hamada S, Okita TW. Targeting of RNAs to ER Subdomains and its Relationship to Protein Localization. PLANT CELL MONOGRAPHS 2006. [DOI: 10.1007/7089_064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|