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Chevalier Q, Huchelmann A, Debié P, Mercier P, Hartmann M, Vonthron-Sénécheau C, Bach TJ, Schaller H, Hemmerlin A. Methyl-Jasmonate Functions as a Molecular Switch Promoting Cross-Talk between Pathways for the Biosynthesis of Isoprenoid Backbones Used to Modify Proteins in Plants. PLANTS (BASEL, SWITZERLAND) 2024; 13:1110. [PMID: 38674519 PMCID: PMC11055089 DOI: 10.3390/plants13081110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/03/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
In plants, the plastidial mevalonate (MVA)-independent pathway is required for the modification with geranylgeranyl groups of CaaL-motif proteins, which are substrates of protein geranylgeranyltransferase type-I (PGGT-I). As a consequence, fosmidomycin, a specific inhibitor of 1-deoxy-d-xylulose (DX)-5 phosphate reductoisomerase/DXR, the second enzyme in this so-called methylerythritol phosphate (MEP) pathway, also acts as an effective inhibitor of protein prenylation. This can be visualized in plant cells by confocal microscopy by expressing GFP-CaM-CVIL, a prenylation sensor protein. After treatment with fosmidomycin, the plasma membrane localization of this GFP-based sensor is altered, and a nuclear distribution of fluorescence is observed instead. In tobacco cells, a visual screen of conditions allowing membrane localization in the presence of fosmidomycin identified jasmonic acid methyl esther (MeJA) as a chemical capable of gradually overcoming inhibition. Using Arabidopsis protein prenyltransferase loss-of-function mutant lines expressing GFP-CaM-CVIL proteins, we demonstrated that in the presence of MeJA, protein farnesyltransferase (PFT) can modify the GFP-CaM-CVIL sensor, a substrate the enzyme does not recognize under standard conditions. Similar to MeJA, farnesol and MVA also alter the protein substrate specificity of PFT, whereas DX and geranylgeraniol have limited or no effect. Our data suggest that MeJA adjusts the protein substrate specificity of PFT by promoting a metabolic cross-talk directing the origin of the prenyl group used to modify the protein. MVA, or an MVA-derived metabolite, appears to be a key metabolic intermediate for this change in substrate specificity.
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Affiliation(s)
- Quentin Chevalier
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
- Centre National de la Recherche Scientifique, Laboratoire d’Innovation Thérapeutique, Université de Strasbourg, CEDEX, F-67401 Illkirch, France;
| | - Alexandre Huchelmann
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Pauline Debié
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Pierre Mercier
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Michael Hartmann
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Catherine Vonthron-Sénécheau
- Centre National de la Recherche Scientifique, Laboratoire d’Innovation Thérapeutique, Université de Strasbourg, CEDEX, F-67401 Illkirch, France;
| | - Thomas J. Bach
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Hubert Schaller
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
| | - Andréa Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (IBMP), Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France; (Q.C.); (P.D.); (P.M.); (M.H.); (T.J.B.); (H.S.)
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do Carmo Santos ML, Santos TA, Dos Santos Lopes N, Macedo Ferreira M, Martins Alves AM, Pirovani CP, Micheli F. The selenium-independent phospholipid hydroperoxide glutathione peroxidase from Theobroma cacao (TcPHGPX) protects plant cells against damages and cell death. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108332. [PMID: 38224638 DOI: 10.1016/j.plaphy.2023.108332] [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: 09/28/2023] [Revised: 12/02/2023] [Accepted: 12/31/2023] [Indexed: 01/17/2024]
Abstract
Proteins from the glutathione peroxidase (GPX) family, such as GPX4 or PHGPX in animals, are extensively studied for their antioxidant functions and apoptosis inhibition. GPXs can be selenium-independent or selenium-dependent, with selenium acting as a potential cofactor for GPX activity. However, the relationship of plant GPXs to these functions remains unclear. Recent research indicated an upregulation of Theobroma cacao phospholipid hydroperoxide glutathione peroxidase gene (TcPHGPX) expression during early witches' broom disease stages, suggesting the use of antioxidant mechanisms as a plant defense strategy to reduce disease progression. Witches' broom disease, caused by the hemibiotrophic fungus Moniliophthora perniciosa, induces cell death through elicitors like MpNEP2 in advanced infection stages. In this context, in silico and in vitro analyses of TcPHGPX's physicochemical and functional characteristics may elucidate its antioxidant potential and effects against cell death, enhancing understanding of plant GPXs and informing strategies to control witches' broom disease. Results indicated TcPHGPX interaction with selenium compounds, mainly sodium selenite, but without improving the protein function. Protein-protein interaction network suggested cacao GPXs association with glutathione and thioredoxin metabolism, engaging in pathways like signaling, peroxide detection for ABA pathway components, and anthocyanin transport. Tests on tobacco cells revealed that TcPHGPX reduced cell death, associated with decreased membrane damage and H2O2 production induced by MpNEP2. This study is the first functional analysis of TcPHGPX, contributing to knowledge about plant GPXs and supporting studies for witches' broom disease control.
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Affiliation(s)
- Maria Luíza do Carmo Santos
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Taís Araújo Santos
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Natasha Dos Santos Lopes
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Monaliza Macedo Ferreira
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Akyla Maria Martins Alves
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Carlos Priminho Pirovani
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil
| | - Fabienne Micheli
- Universidade Estadual de Santa Cruz (UESC), Departamento de Ciências Biológicas (DCB), Centro de Biotecnologia e Genética (CBG), Rodovia Ilhéus-Itabuna, Km 16, 45662-900, Ilhéus, BA, Brazil; CIRAD, UMR AGAP, F-34398, Montpellier, France.
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Liao P, Lung SC, Chan WL, Hu M, Kong GKW, Bach TJ, Hao Q, Lo C, Chye ML. Overexpression and Inhibition of 3-Hydroxy-3-Methylglutaryl-CoA Synthase Affect Central Metabolic Pathways in Tobacco. PLANT & CELL PHYSIOLOGY 2021; 62:205-218. [PMID: 33340324 DOI: 10.1093/pcp/pcaa154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/28/2020] [Indexed: 06/12/2023]
Abstract
Little has been established on the relationship between the mevalonate (MVA) pathway and other metabolic pathways except for the sterol and glucosinolate biosynthesis pathways. In the MVA pathway, 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS) catalyzes the condensation of acetoacetyl-CoA and acetyl-CoA to form 3-hydroxy-3-methylglutaryl-coenzyme A. Our previous studies had shown that, while the recombinant Brassica juncea HMGS1 (BjHMGS1) mutant S359A displayed 10-fold higher enzyme activity than wild-type (wt) BjHMGS1, transgenic tobacco overexpressing S359A (OE-S359A) exhibited higher sterol content, growth rate and seed yield than OE-wtBjHMGS1. Herein, untargeted proteomics and targeted metabolomics were employed to understand the phenotypic effects of HMGS overexpression in tobacco by examining which other metabolic pathways were affected. Sequential window acquisition of all theoretical mass spectra quantitative proteomics analysis on OE-wtBjHMGS1 and OE-S359A identified the misregulation of proteins in primary metabolism and cell wall modification, while some proteins related to photosynthesis and the tricarboxylic acid cycle were upregulated in OE-S359A. Metabolomic analysis indicated corresponding changes in carbohydrate, amino acid and fatty acid contents in HMGS-OEs, and F-244, a specific inhibitor of HMGS, was applied successfully on tobacco to confirm these observations. Finally, the crystal structure of acetyl-CoA-liganded S359A revealed that improved activity of S359A likely resulted from a loss in hydrogen bonding between Ser359 and acyl-CoA, which is evident in wtBjHMGS1. This work suggests that regulation of plant growth by HMGS can influence the central metabolic pathways. Furthermore, this study demonstrates that the application of the HMGS-specific inhibitor (F-244) in tobacco represents an effective approach for studying the HMGS/MVA pathway.
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Affiliation(s)
- Pan Liao
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Shiu-Cheung Lung
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wai Lung Chan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Menglong Hu
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | | | - Thomas J Bach
- Centre National de la Recherche Scientifique, UPR 2357, Institut de Biologie Mol�culaire des Plantes, Universit� de Strasbourg, Strasbourg 67084, France
| | - Quan Hao
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, CUHK, Shatin, New Territories, Hong Kong, China
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Sarkar D, Maranas CD. SNPeffect: identifying functional roles of SNPs using metabolic networks. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:512-531. [PMID: 32167625 PMCID: PMC9328443 DOI: 10.1111/tpj.14746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/20/2020] [Indexed: 05/04/2023]
Abstract
Genetic sources of phenotypic variation have been a focus of plant studies aimed at improving agricultural yield and understanding adaptive processes. Genome-wide association studies identify the genetic background behind a trait by examining associations between phenotypes and single-nucleotide polymorphisms (SNPs). Although such studies are common, biological interpretation of the results remains a challenge; especially due to the confounding nature of population structure and the systematic biases thus introduced. Here, we propose a complementary analysis (SNPeffect) that offers putative genotype-to-phenotype mechanistic interpretations by integrating biochemical knowledge encoded in metabolic models. SNPeffect is used to explain differential growth rate and metabolite accumulation in A. thaliana and P. trichocarpa accessions as the outcome of SNPs in enzyme-coding genes. To this end, we also constructed a genome-scale metabolic model for Populus trichocarpa, the first for a perennial woody tree. As expected, our results indicate that growth is a complex polygenic trait governed by carbon and energy partitioning. The predicted set of functional SNPs in both species are associated with experimentally characterized growth-determining genes and also suggest putative ones. Functional SNPs were found in pathways such as amino acid metabolism, nucleotide biosynthesis, and cellulose and lignin biosynthesis, in line with breeding strategies that target pathways governing carbon and energy partition.
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Affiliation(s)
- Debolina Sarkar
- Department of Chemical EngineeringPennsylvania State UniversityUniversity ParkPAUSA
| | - Costas D. Maranas
- Department of Chemical EngineeringPennsylvania State UniversityUniversity ParkPAUSA
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Wei H, Xu C, Movahedi A, Sun W, Li D, Zhuge Q. Characterization and Function of 3-Hydroxy-3-Methylglutaryl-CoA Reductase in Populus trichocarpa: Overexpression of PtHMGR Enhances Terpenoids in Transgenic Poplar. FRONTIERS IN PLANT SCIENCE 2019; 10:1476. [PMID: 31803212 PMCID: PMC6872958 DOI: 10.3389/fpls.2019.01476] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 10/24/2019] [Indexed: 05/26/2023]
Abstract
In the mevalonic acid (MVA) pathway, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) is considered the first rate-limiting enzyme in isoprenoid biosynthesis. In this study, we cloned a full-length cDNA from Populus trichocarpa with an open reading frame of 1,734 bp. The deduced PtHMGR sequence contained two HMG-CoA motifs and two NADPH motifs, which exhibited homology with HMGR proteins from other species. Subsequently, truncated PtHMGR was expressed in Escherichia coli BL21 (DE3) cells, and enzyme activity analysis revealed that the truncated PtHMGR protein could catalyze the reaction of HMG-CoA and NADPH to form MVA. Relative expression analysis suggests that PtHMGR expression varies among tissues and that PtHMGR responds significantly to abscisic acid (ABA), NaCl, PEG6000, hydrogen peroxide (H2O2), and cold stresses. We used polymerase chain reaction (PCR) analysis to select transgenic Nanlin 895 poplars (Populus× euramericana cv.) and quantitative reverse-transcription PCR (qRT-PCR) to show that PtHMGR expression levels were 3- to 10-fold higher in transgenic lines than in wild-type (WT) poplars. qRT-PCR was also used to determine transcript levels of methylerythritol phosphate (MEP)-, MVA-, and downstream-related genes, indicating that overexpression of PtHMGR not only affects expression levels of MVA-related genes, but also those of MEP-related genes. We also measured the content of terpenoids including ABA, gibberellic acid (GA), carotenes, and lycopene. PtHMGR overexpression significantly increased ABA, GA, carotene, and lycopene content, indicating that PtHMGR participates in the regulation of terpenoid compound synthesis.
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Affiliation(s)
- Hui Wei
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Chen Xu
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
- Jiangsu Provincial Key Construction Laboratory of Special Biomass Resource Utilization, Nanjing Xiaozhuang University, Nanjing, China
| | - Ali Movahedi
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Weibo Sun
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Dawei Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Qiang Zhuge
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
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Hemmerlin A, Huchelmann A, Tritsch D, Schaller H, Bach TJ. The specific molecular architecture of plant 3-hydroxy-3-methylglutaryl-CoA lyase. J Biol Chem 2019; 294:16186-16197. [PMID: 31515272 DOI: 10.1074/jbc.ra119.008839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/20/2019] [Indexed: 11/06/2022] Open
Abstract
3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase (HMGL) is involved in branched-chain amino acid catabolism leading to acetyl-CoA production. Here, using bioinformatics analyses and protein sequence alignments, we found that in Arabidopsis thaliana a single gene encodes two HMGL isoforms differing in size (51 kDa, HMGL51 and 46 kDa, HMGL46). Similar to animal HMGLs, both isoforms comprised a C-terminal type 1 peroxisomal retention motif, and HMGL51 contained a mitochondrial leader peptide. We observed that only a shortened HMGL (35 kDa, HMGL35) is conserved across all kingdoms of life. Most notably, all plant HMGLs also contained a specific N-terminal extension (P100) that is located between the N-terminal mitochondrial targeting sequence TP35 and HMGL35 and is absent in bacteria and other eukaryotes. Interestingly, using HMGL enzyme assays, we found that rather than HMGL46, homodimeric recombinant HMGL35 is the active enzyme catalyzing acetyl-CoA and acetoacetate synthesis when incubated with (S)-HMG-CoA. This suggested that the plant-specific P100 peptide may inactivate HMGL according to specific physiological requirements. Therefore, we investigated whether the P100 peptide in HMGL46 alters its activity, possibly by modifying the HMGL46 structure. We found that induced expression of a cytosolic HMGL35 version in A. thaliana delays germination and leads to rapid wilting and chlorosis in mature plants. Our results suggest that in plants, P100-mediated HMGL inactivation outside of peroxisomes or mitochondria is crucial, protecting against potentially cytotoxic effects of HMGL activity while it transits to these organelles.
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Affiliation(s)
- Andréa Hemmerlin
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Alexandre Huchelmann
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Denis Tritsch
- Institut de Chimie de Strasbourg, 4 rue Blaise Pascal, F-67081 Strasbourg, France
| | - Hubert Schaller
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
| | - Thomas J Bach
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg, France
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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/31/2015] [Indexed: 03/26/2024] Open
Abstract
In a preceding study we have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was there demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, in this initial study complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established now new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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Gas-Pascual E, Simonovik B, Schaller H, Bach TJ. Inhibition of Cycloartenol Synthase (CAS) Function in Tobacco BY-2 Cells. Lipids 2015; 50:761-72. [PMID: 26033687 DOI: 10.1007/s11745-015-4036-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 05/15/2015] [Indexed: 01/06/2023]
Abstract
Tobacco BY-2 cell suspensions are our preferred model for studying isoprenoid biosynthesis pathways, due to their easy genetic transformation and the efficient absorption of metabolic precursors, intermediates, and/or inhibitors. Using this model system, we have analyzed the effects of chemical and genetic blockage of cycloartenol synthase (CAS, EC 5.4.99.8), an oxidosqualene cyclase that catalyzes the first committed step in the sterol pathway of plants. BY-2 cells were treated with RO 48-8071, a potent inhibitor of oxidosqualene cyclization. Short-term treatments (24 h) resulted in accumulation of oxidosqualene with no changes in the final sterol products. Interestingly, long-term treatments (6 days) induced down-regulation in gene expression not only of CAS but also of the SMT2 gene coding sterol methyltransferase 2 (EC 2.1.1.41). This explains some of the increase in 24-methyl sterols at the expense of the 24-ethyl sterols stigmasterol and sitosterol. In our alternative strategy, CAS gene expression was partially blocked by using an inducible artificial microRNA. The limited effectiveness of this approach might be explained by some dependence of the machinery for RNAi formation on an operating MVA/sterol pathway. For comparison we checked the effect of RO 48-8071 on a green cell suspension of Arabidopsis and on seedlings, containing a small spectrum of triterpenes besides phytosterols. Triterpenes remained essentially unaffected, but phytosterol accumulation was clearly diminished.
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Affiliation(s)
- Elisabet Gas-Pascual
- Department of Horticulture and Crop Science, The Ohio State University, Wooster, OH, 44691, USA
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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 11/20/2022] Open
Abstract
We have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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Liao P, Wang H, Hemmerlin A, Nagegowda DA, Bach TJ, Wang M, Chye ML. Past achievements, current status and future perspectives of studies on 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS) in the mevalonate (MVA) pathway. PLANT CELL REPORTS 2014; 33:1005-22. [PMID: 24682521 DOI: 10.1007/s00299-014-1592-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 02/24/2014] [Indexed: 05/09/2023]
Abstract
HMGS functions in phytosterol biosynthesis, development and stress responses. F-244 could specifically-inhibit HMGS in tobacco BY-2 cells and Brassica seedlings. An update on HMGS from higher plants is presented. 3-Hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS) is the second enzyme in the mevalonate pathway of isoprenoid biosynthesis and catalyzes the condensation of acetoacetyl-CoA and acetyl-CoA to produce S-3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). Besides HMG-CoA reductase (HMGR), HMGS is another key enzyme in the regulation of cholesterol and ketone bodies in mammals. In plants, it plays an important role in phytosterol biosynthesis. Here, we summarize the past investigations on eukaryotic HMGS with particular focus on plant HMGS, its enzymatic properties, gene expression, protein structure, and its current status of research in China. An update of the findings on HMGS from animals (human, rat, avian) to plants (Brassica juncea, Hevea brasiliensis, Arabidopsis thaliana) will be discussed. Current studies on HMGS have been vastly promoted by developments in biochemistry and molecular biology. Nonetheless, several limitations have been encountered, thus some novel advances in HMGS-related research that have recently emerged will be touched on.
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Affiliation(s)
- Pan Liao
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China,
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11
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Denev I, Deneva B, Batchvarova R. The Biosynthetic Origin of Germination Stimulants for Orobanche Ramosa (L.) in Tobacco and Arabidopsis. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2007.10817413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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12
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Zhao S, Wang L, Liu L, Liang Y, Sun Y, Wu J. Both the mevalonate and the non-mevalonate pathways are involved in ginsenoside biosynthesis. PLANT CELL REPORTS 2014; 33:393-400. [PMID: 24258243 DOI: 10.1007/s00299-013-1538-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 10/17/2013] [Accepted: 11/04/2013] [Indexed: 05/06/2023]
Abstract
KEY MESSAGE When one of them was inhibited, the two pathways could compensate with each other to guarantee normal growth. Moreover, the sterol biosynthesis inhibitor miconazole could enhance ginsenoside level. ABSTRACT Ginsenosides, a kind of triterpenoid saponins derived from isopentenyl pyrophosphate (IPP), represent the main pharmacologically active constituents of ginseng. In plants, two pathways contribute to IPP biosynthesis, namely, the mevalonate pathway in cytosol and the non-mevalonate pathway in plastids. This motivates biologists to clarify the roles of the two pathways in biosynthesis of IPP-derived compounds. Here, we demonstrated that both pathways are involved in ginsenoside biosynthesis, based on the analysis of the effects from suppressing either or both of the pathways on ginsenoside accumulation in Panax ginseng hairy roots with mevinolin and fosmidomycin as specific inhibitors for the mevalonate and the non-mevalonate pathways, respectively. Furthermore, the sterol biosynthesis inhibitor miconazole could enhance ginsenoside levels in the hairy roots. These results shed some light on the way toward better understanding of ginsenoside biosynthesis.
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Affiliation(s)
- Shoujing Zhao
- College of Biological and Agricultural Engineering, Jilin University, Changchun, 130022, China
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Huchelmann A, Gastaldo C, Veinante M, Zeng Y, Heintz D, Tritsch D, Schaller H, Rohmer M, Bach TJ, Hemmerlin A. S-carvone suppresses cellulase-induced capsidiol production in Nicotiana tabacum by interfering with protein isoprenylation. PLANT PHYSIOLOGY 2014; 164:935-50. [PMID: 24367019 PMCID: PMC3912117 DOI: 10.1104/pp.113.232546] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 12/20/2013] [Indexed: 05/27/2023]
Abstract
S-Carvone has been described as a negative regulator of mevalonic acid (MVA) production by interfering with 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGR) activity, a key player in isoprenoid biosynthesis. The impact of this monoterpene on the production of capsidiol in Nicotiana tabacum, an assumed MVA-derived sesquiterpenoid phytoalexin produced in response to elicitation by cellulase, was investigated. As expected, capsidiol production, as well as early stages of elicitation such as hydrogen peroxide production or stimulation of 5-epi-aristolochene synthase activity, were repressed. Despite the lack of capsidiol synthesis, apparent HMGR activity was boosted. Feeding experiments using (1-13C)Glc followed by analysis of labeling patterns by 13C-NMR, confirmed an MVA-dependent biosynthesis; however, treatments with fosmidomycin, an inhibitor of the MVA-independent 2-C-methyl-D-erythritol 4-phosphate (MEP) isoprenoid pathway, unexpectedly down-regulated the biosynthesis of this sesquiterpene as well. We postulated that S-carvone does not directly inhibit the production of MVA by inactivating HMGR, but possibly targets an MEP-derived isoprenoid involved in the early steps of the elicitation process. A new model is proposed in which the monoterpene blocks an MEP pathway-dependent protein geranylgeranylation necessary for the signaling cascade. The production of capsidiol was inhibited when plants were treated with some inhibitors of protein prenylation or by further monoterpenes. Moreover, S-carvone hindered isoprenylation of a prenylable GFP indicator protein expressed in N. tabacum cell lines, which can be chemically complemented with geranylgeraniol. The model was further validated using N. tabacum cell extracts or recombinant N. tabacum protein prenyltransferases expressed in Escherichia coli. Our study endorsed a reevaluation of the effect of S-carvone on plant isoprenoid metabolism.
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Affiliation(s)
- Alexandre Huchelmann
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Clément Gastaldo
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Mickaël Veinante
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | | | - Dimitri Heintz
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Denis Tritsch
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Hubert Schaller
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Michel Rohmer
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
| | - Thomas J. Bach
- Unité Propre de Recherche 2357, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, conventionné avec l’Université de Strasbourg, F-67083 Strasbourg, France (Al.H., M.V., Y.Z., D.H., H.S., T.J.B., An.H.); and
- Institut de Chimie Unité Mixte de Recherche 7177, Université de Strasbourg/Centre National de la Recherche Scientifique, F-67070 Strasbourg, France (C.G., D.T., M.R.)
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Villela-Dias C, Camillo LR, de Oliveira GAP, Sena JAL, Santiago AS, de Sousa STP, Mendes JS, Pirovani CP, Alvim FC, Costa MGC. Nep1-like protein from Moniliophthora perniciosa induces a rapid proteome and metabolome reprogramming in cells of Nicotiana benthamiana. PHYSIOLOGIA PLANTARUM 2014; 150:1-17. [PMID: 23586401 DOI: 10.1111/ppl.12061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 04/01/2013] [Accepted: 04/08/2013] [Indexed: 06/02/2023]
Abstract
NEP1 (necrosis- and ethylene-inducing peptide 1)-like proteins (NLPs) have been identified in a variety of taxonomically unrelated plant pathogens and share a common characteristic of inducing responses of plant defense and cell death in dicotyledonous plants. Even though some aspects of NLP action have been well characterized, nothing is known about the global range of modifications in proteome and metabolome of NLP-treated plant cells. Here, using both proteomic and metabolomic approaches we were able to identify the global molecular and biochemical changes in cells of Nicotiana benthamiana elicited by short-term treatment with MpNEP2, a NLP of Moniliophthora perniciosa, the basidiomycete responsible for the witches' broom disease on cocoa (Theobroma cacao L.). Approximately 100 protein spots were collected from 2-DE gels in each proteome, with one-third showing more than twofold differences in the expression values. Fifty-three such proteins were identified by mass spectrometry (MS)/MS and mapped into specific metabolic pathways and cellular processes. Most MpNEP2 upregulated proteins are involved in nucleotide-binding function and oxidoreductase activity, whereas the downregulated proteins are mostly involved in glycolysis, response to stress and protein folding. Thirty metabolites were detected by gas spectrometry (GC)/MS and semi-quantified, of which eleven showed significant differences between the treatments, including proline, alanine, myo-inositol, ethylene, threonine and hydroxylamine. The global changes described affect the reduction-oxidation reactions, ATP biosynthesis and key signaling molecules as calcium and hydrogen peroxide. These findings will help creating a broader understanding of NLP-mediated cell death signaling in plants.
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Affiliation(s)
- Cristiano Villela-Dias
- Laboratório de Proteômica, Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil; Mars Center for Cocoa Science, CP 55, Itajuipe, Bahia, Brazil
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15
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Ramak P, Kazempour Osaloo S, Ebrahimzadeh H, Sharifi M, Behmanesh M. Inhibition of the mevalonate pathway enhances carvacrol biosynthesis and DXR gene expression in shoot cultures of Satureja khuzistanica Jamzad. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:1187-93. [PMID: 23611428 DOI: 10.1016/j.jplph.2013.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 03/22/2013] [Accepted: 03/24/2013] [Indexed: 05/25/2023]
Abstract
Carvacrol is a major component of Satureja khuzistanica Jamzad (≤90%) that has significant antimicrobial and antioxidant properties. Considering the specific capabilities of S. khuzistanica to produce highly pure carvacrol, this plant is an important potential source of carvacrol that could address the abundant consumption and increasing demand for this monoterpene in current world markets. This research was performed to better understand the process of biosynthesis and accumulation of carvacrol in S. khuzistanica. Tests were performed on shoot cultures of S. khuzistanica in Linsmaier-Skoog (LS) medium treated with different concentrations of fosmidomycin (an inhibitor of the non-mevalonate pathway) and mevinolin (an inhibitor of the mevalonate pathway) for 21 days at the following concentrations: 0, 10, 25, 50, 75 and 100 μM. The present study demonstrated that the MEP pathway is the major pathway that provides IPP for the biosynthesis of carvacrol, and the expression and activity levels of the DXR enzyme have a critical effect on carvacrol biosynthesis. Surprisingly, Mevinolin at concentrations of 75 and 100 μM increased the carvacrol content and the DXR activity and gene expression in S. khuzistanica plantlets.
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Affiliation(s)
- Parvin Ramak
- Department of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, 14115-154, Tehran, Iran.
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16
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Hartmann M, Hemmerlin A, Gas-Pascual E, Gerber E, Tritsch D, Rohmer M, Bach TJ. The effect of MEP pathway and other inhibitors on the intracellular localization of a plasma membrane-targeted, isoprenylable GFP reporter protein in tobacco BY-2 cells. F1000Res 2013; 2:170. [PMID: 24555083 DOI: 10.12688/f1000research.2-170.v1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/01/2013] [Indexed: 11/20/2022] Open
Abstract
We have established anin vivovisualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, based on the expression of a dexamethasone-inducible GFP fused to the carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with known inhibitors like oxoclomazone and fosmidomycin, as well as inhibition of the protein geranylgeranyltransferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect the localization. During the present work, this test system has been used to examine the effect of newly designed inhibitors of the MEP pathway and inhibitors of sterol biosynthesis such as squalestatin, terbinafine and Ro48-8071. In addition, we also studied the impact of different post-prenylation inhibitors or those suspected to affect the transport of proteins to the plasma membrane on the localization of the geranylgeranylable fusion protein GFP-BD-CVIL.
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Affiliation(s)
- Michael Hartmann
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Institute of Biological Chemistry, Washington State University, Pullman WA, 99164-6340, USA
| | - Andrea Hemmerlin
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France
| | - Elisabet Gas-Pascual
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Department of Horticulture and Crop Science, Ohio State University, Wooster OH, 44691, USA
| | - Esther Gerber
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Deinove SA, F-34830 Clapiers, France
| | - Denis Tritsch
- UMR 7177 CNRS, Laboratoire de Chimie et Biochimie des Microorganismes, Institut de Chimie de Strasbourg, Université de Strasbourg, F-67008 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS, Laboratoire de Chimie et Biochimie des Microorganismes, Institut de Chimie de Strasbourg, Université de Strasbourg, F-67008 Strasbourg, France
| | - Thomas J Bach
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France
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Hartmann M, Hemmerlin A, Gas-Pascual E, Gerber E, Tritsch D, Rohmer M, Bach TJ. The effect of MEP pathway and other inhibitors on the intracellular localization of a plasma membrane-targeted, isoprenylable GFP reporter protein in tobacco BY-2 cells. F1000Res 2013; 2:170. [PMID: 24555083 PMCID: PMC3886798 DOI: 10.12688/f1000research.2-170.v2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/12/2013] [Indexed: 11/20/2022] Open
Abstract
We have established an
in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, based on the expression of a dexamethasone-inducible GFP fused to the carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with known inhibitors like oxoclomazone and fosmidomycin, as well as inhibition of the protein geranylgeranyltransferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect the localization. During the present work, this test system has been used to examine the effect of newly designed inhibitors of the MEP pathway and inhibitors of sterol biosynthesis such as squalestatin, terbinafine and Ro48-8071. In addition, we also studied the impact of different post-prenylation inhibitors or those suspected to affect the transport of proteins to the plasma membrane on the localization of the geranylgeranylable fusion protein GFP-BD-CVIL.
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Affiliation(s)
- Michael Hartmann
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Institute of Biological Chemistry, Washington State University, Pullman WA, 99164-6340, USA
| | - Andrea Hemmerlin
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France
| | - Elisabet Gas-Pascual
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Department of Horticulture and Crop Science, Ohio State University, Wooster OH, 44691, USA
| | - Esther Gerber
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France ; Current address: Deinove SA, F-34830 Clapiers, France
| | - Denis Tritsch
- UMR 7177 CNRS, Laboratoire de Chimie et Biochimie des Microorganismes, Institut de Chimie de Strasbourg, Université de Strasbourg, F-67008 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS, Laboratoire de Chimie et Biochimie des Microorganismes, Institut de Chimie de Strasbourg, Université de Strasbourg, F-67008 Strasbourg, France
| | - Thomas J Bach
- Département Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, F-67083 Strasbourg, France
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Hemmerlin A. Post-translational events and modifications regulating plant enzymes involved in isoprenoid precursor biosynthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 203-204:41-54. [PMID: 23415327 DOI: 10.1016/j.plantsci.2012.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 12/05/2012] [Accepted: 12/20/2012] [Indexed: 05/23/2023]
Abstract
Identification of regulatory enzymes is fundamental for engineering metabolic pathways such as the isoprenoid one. All too often, investigation of gene expression remains the major trend in unraveling regulation mechanisms of the isoprenoid cytosolic mevalonate and the plastid-localized methylerythritol phosphate metabolic pathways. But such metabolic regulatory enzymes are frequently multilevel-regulated, especially at a post-translational level. A prominent example is the endoplasmic reticulum-bound 3-hydroxy-3-methylglutaryl coenzyme A reductase catalyzing the synthesis of mevalonic acid. Despite the discovery and the intense efforts made to understand regulation of the methylerythritol phosphate pathway, this enzyme remains a leading player in the regulation of the whole isoprenoid pathway. Strict correlation between this enzyme's gene expression, protein level and enzyme activity is not observed, thus confirming multilevel-regulation. In this context, besides post-translational modifications of proteins, we have to consider feedback of metabolic flow and allosteric regulation, alternative protein structures, targeted proteolysis and/or redox regulation. Such multilevel-regulation processes deliver a range of benefits including rapid response to environmental and physiological challenges or metabolic fluctuations. This review specially emphasizes essential functions of these post-translational events that permit the close regulation of key enzymes involved in plant isoprenoid precursor biosynthesis.
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Affiliation(s)
- Andréa Hemmerlin
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, IBMP-CNRS-UPR2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg Cedex, France.
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19
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Kumar S, Hahn FM, Baidoo E, Kahlon TS, Wood DF, McMahan CM, Cornish K, Keasling JD, Daniell H, Whalen MC. Remodeling the isoprenoid pathway in tobacco by expressing the cytoplasmic mevalonate pathway in chloroplasts. Metab Eng 2012; 14:19-28. [PMID: 22123257 PMCID: PMC5767336 DOI: 10.1016/j.ymben.2011.11.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 10/20/2011] [Accepted: 11/08/2011] [Indexed: 01/06/2023]
Abstract
Metabolic engineering to enhance production of isoprenoid metabolites for industrial and medical purposes is an important goal. The substrate for isoprenoid synthesis in plants is produced by the mevalonate pathway (MEV) in the cytosol and by the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway in plastids. A multi-gene approach was employed to insert the entire cytosolic MEV pathway into the tobacco chloroplast genome. Molecular analysis confirmed the site-specific insertion of seven transgenes and homoplasmy. Functionality was demonstrated by unimpeded growth on fosmidomycin, which specifically inhibits the MEP pathway. Transplastomic plants containing the MEV pathway genes accumulated higher levels of mevalonate, carotenoids, squalene, sterols, and triacyglycerols than control plants. This is the first time an entire eukaryotic pathway with six enzymes has been transplastomically expressed in plants. Thus, we have developed an important tool to redirect metabolic fluxes in the isoprenoid biosynthesis pathway and a viable multigene strategy for engineering metabolism in plants.
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Affiliation(s)
- Shashi Kumar
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
- Yulex Corporation, Maricopa, AZ, United States
| | - Frederick M. Hahn
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
| | - Edward Baidoo
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, United States
| | - Talwinder S. Kahlon
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
| | - Delilah F. Wood
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
| | - Colleen M. McMahan
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
| | | | - Jay D. Keasling
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, United States
| | - Henry Daniell
- Department of Molecular Biology & Microbiology, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Maureen C. Whalen
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA, United States
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20
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Hemmerlin A, Harwood JL, Bach TJ. A raison d'être for two distinct pathways in the early steps of plant isoprenoid biosynthesis? Prog Lipid Res 2011; 51:95-148. [PMID: 22197147 DOI: 10.1016/j.plipres.2011.12.001] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/28/2011] [Accepted: 12/05/2011] [Indexed: 12/12/2022]
Abstract
When compared to other organisms, plants are atypical with respect to isoprenoid biosynthesis: they utilize two distinct and separately compartmentalized pathways to build up isoprene units. The co-existence of these pathways in the cytosol and in plastids might permit the synthesis of many vital compounds, being essential for a sessile organism. While substrate exchange across membranes has been shown for a variety of plant species, lack of complementation of strong phenotypes, resulting from inactivation of either the cytosolic pathway (growth and development defects) or the plastidial pathway (pigment bleaching), seems to be surprising at first sight. Hundreds of isoprenoids have been analyzed to determine their biosynthetic origins. It can be concluded that in angiosperms, under standard growth conditions, C₂₀-phytyl moieties, C₃₀-triterpenes and C₄₀-carotenoids are made nearly exclusively within compartmentalized pathways, while mixed origins are widespread for other types of isoprenoid-derived molecules. It seems likely that this coexistence is essential for the interaction of plants with their environment. A major purpose of this review is to summarize such observations, especially within an ecological and functional context and with some emphasis on regulation. This latter aspect still requires more work and present conclusions are preliminary, although some general features seem to exist.
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Affiliation(s)
- Andréa Hemmerlin
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, IBMP-CNRS-UPR2357, Université de Strasbourg, 28 Rue Goethe, F-67083 Strasbourg Cedex, France.
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21
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Andrews M, Huizinga DH, Crowell DN. The CaaX specificities of Arabidopsis protein prenyltransferases explain era1 and ggb phenotypes. BMC PLANT BIOLOGY 2010; 10:118. [PMID: 20565889 PMCID: PMC3017772 DOI: 10.1186/1471-2229-10-118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 06/18/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND Protein prenylation is a common post-translational modification in metazoans, protozoans, fungi, and plants. This modification, which mediates protein-membrane and protein-protein interactions, is characterized by the covalent attachment of a fifteen-carbon farnesyl or twenty-carbon geranylgeranyl group to the cysteine residue of a carboxyl terminal CaaX motif. In Arabidopsis, era1 mutants lacking protein farnesyltransferase exhibit enlarged meristems, supernumerary floral organs, an enhanced response to abscisic acid (ABA), and drought tolerance. In contrast, ggb mutants lacking protein geranylgeranyltransferase type 1 exhibit subtle changes in ABA and auxin responsiveness, but develop normally. RESULTS We have expressed recombinant Arabidopsis protein farnesyltransferase (PFT) and protein geranylgeranyltransferase type 1 (PGGT1) in E. coli and characterized purified enzymes with respect to kinetic constants and substrate specificities. Our results indicate that, whereas PFT exhibits little specificity for the terminal amino acid of the CaaX motif, PGGT1 exclusively prenylates CaaX proteins with a leucine in the terminal position. Moreover, we found that different substrates exhibit similar K(m) but different k(cat) values in the presence of PFT and PGGT1, indicating that substrate specificities are determined primarily by reactivity rather than binding affinity. CONCLUSIONS The data presented here potentially explain the relatively strong phenotype of era1 mutants and weak phenotype of ggb mutants. Specifically, the substrate specificities of PFT and PGGT1 suggest that PFT can compensate for loss of PGGT1 in ggb mutants more effectively than PGGT1 can compensate for loss of PFT in era1 mutants. Moreover, our results indicate that PFT and PGGT1 substrate specificities are primarily due to differences in catalysis, rather than differences in substrate binding.
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Affiliation(s)
- Michelle Andrews
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | - David H Huizinga
- Department of Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA
- Dow AgroSciences LLC, Indianapolis, IN 46268, USA
| | - Dring N Crowell
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
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22
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Tang J, Kobayashi K, Suzuki M, Matsumoto S, Muranaka T. The mitochondrial PPR protein LOVASTATIN INSENSITIVE 1 plays regulatory roles in cytosolic and plastidial isoprenoid biosynthesis through RNA editing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:456-66. [PMID: 19929879 DOI: 10.1111/j.1365-313x.2009.04082.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Unlike animals, plants synthesize isoprenoids via two pathways, the cytosolic mevalonate (MVA) pathway and the plastidial 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway. Little information is known about the mechanisms that regulate these complex biosynthetic networks over multiple organelles. To understand such regulatory mechanisms of the biosynthesis of isoprenoids in plants, we previously characterized the Arabidopsis mutant, lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, specific inhibitors of the MVA and MEP pathways, respectively. LOI1 encodes a pentatricopeptide repeat (PPR) protein localized in mitochondria that is thought to have RNA binding ability and function in post-transcriptional regulation of mitochondrial gene expression. LOI1 belongs to the DYW subclass of PPR proteins, which is hypothesized to be correlated with RNA editing. As a result of analysis of RNA editing of mitochondrial genes in loi1, a defect in RNA editing of three genes, nad4, ccb203 and cox3, was identified in loi1. These genes are related to the respiratory chain. Wild type (WT) treated with some respiration inhibitors mimicked the loi1 phenotype. Interestingly, HMG-CoA reductase activity of WT treated with lovastatin combined with antimycin A, an inhibitor of complex III in the respiratory chain, was higher than that of WT treated with only lovastatin, despite the lack of alteration of transcript or protein levels of HMGR. These results suggest that HMGR enzyme activity is regulated through the respiratory cytochrome pathway. Although various mechanisms exist for isoprenoid biosynthesis, our studies demonstrate the novel possibility that mitochondrial respiration plays potentially regulatory roles in isoprenoid biosynthesis.
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Affiliation(s)
- Jianwei Tang
- RIKEN Plant Science Center, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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23
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Gerber E, Hemmerlin A, Bach TJ. Chapter 9 The Role of Plastids in Protein Geranylgeranylation in Tobacco BY-2 Cells. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/978-90-481-8531-3_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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24
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Huang JZ, Cheng TC, Wen PJ, Hsieh MH, Chen FC. Molecular characterization of the Oncidium orchid HDR gene encoding 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase, the last step of the methylerythritol phosphate pathway. PLANT CELL REPORTS 2009; 28:1475-86. [PMID: 19636561 DOI: 10.1007/s00299-009-0747-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2009] [Revised: 07/06/2009] [Accepted: 07/10/2009] [Indexed: 05/23/2023]
Abstract
Two pathways are used by higher plants for the biosynthesis of isoprenoid precursors: the mevalonate pathway in the cytosol and a 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway in the plastids, with 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR) catalyzing the last step in the MEP pathway. In order to understand the contribution of MEP pathway in isoprenoid biosynthesis of Oncidium orchid, a full-length cDNA corresponding to HDR from the flower tissues of Oncidium Gower Ramsey was cloned. The deduced OncHDR amino acid sequence contains a plastid signal peptide at the N-terminus and four conserved cysteine residues. RT-PCR analysis of HDR in Oncidium flowering plants revealed ubiquitous expression in organs and tissues, with preferential expression in the floral organs. Phylogenetic analysis revealed evolutionary conservation of the encoding HDR protein sequence. The genomic sequence of the HDR in Oncidium is similar to that in Arabidopsis, grape, and rice in structure. Successful complementation by OncHDR of an E. coli hdr(-) mutant confirmed its function. Transgenic tobacco carrying the OncHDR promoter-GUS gene fusion showed expression in most tissues, as well as in reproductive organs, as revealed by histochemical staining. Light induced strong GUS expression driven by the OncHDR promoter in transgenic tobacco seedlings. Taken together, our data suggest a role for OncHDR as a light-activated gene.
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Affiliation(s)
- Jian-Zhi Huang
- Institute of Biotechnology, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
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25
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Suzuki M, Nakagawa S, Kamide Y, Kobayashi K, Ohyama K, Hashinokuchi H, Kiuchi R, Saito K, Muranaka T, Nagata N. Complete blockage of the mevalonate pathway results in male gametophyte lethality. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2055-64. [PMID: 19363204 PMCID: PMC2682496 DOI: 10.1093/jxb/erp073] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 02/23/2009] [Accepted: 02/23/2009] [Indexed: 05/20/2023]
Abstract
Plants have two isoprenoid biosynthetic pathways: the cytosolic mevalonate (MVA) pathway and the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Since the discovery of the MEP pathway, possible metabolic cross-talk between these pathways has prompted intense research. Although many studies have shown the existence of such cross-talk using feeding experiments, it remains to be determined if native cross-talk, rather than exogenously applied metabolites, can compensate for complete blockage of the MVA pathway. Previously, Arabidopsis mutants for HMG1 and HMG2 encoding HMG-CoA reductase (HMGR) were isolated. Although it was shown that HMGR1 is a functional HMGR, the enzyme activity of HMGR2 has not been confirmed. It is demonstrated here that HMG2 encodes a functional reductase with similar activity to HMGR1, using enzyme assays and complementation experiments. To estimate the contribution of native cross-talk, an attempt was made to block the MVA pathway by making double mutants lacking both HMG1 and HMG2, but no double homozygotes were detected in the progeny of self-pollinated HMG1/hmg1 hmg2/hmg2 plants. hmg1 hmg2 male gametophytes appeared to be lethal based on crossing experiments, and microscopy indicated that approximately 50% of the microspores from the HMG1/hmg1 hmg2/hmg2 plant appeared shrunken and exhibited poorly defined endoplasmic reticulum membranes. In situ hybridization showed that HMG1 transcripts were expressed in both the tapetum and microspores, while HMG2 mRNA appeared only in microspores. It is concluded that native cross-talk from the plastid cannot compensate for complete blockage of the MVA pathway, at least during male gametophyte development, because either HMG1 or HMG2 is required for male gametophyte development.
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Affiliation(s)
- Masashi Suzuki
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Shoko Nakagawa
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Science, Japan Women's University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo, 112-8681 Japan
| | - Yukiko Kamide
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Keiko Kobayashi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Kiyoshi Ohyama
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Hiromi Hashinokuchi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Reiko Kiuchi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Kazuki Saito
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, Chiba, 263-8522 Japan
| | - Toshiya Muranaka
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813 Japan
| | - Noriko Nagata
- Graduate School of Science, Japan Women's University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo, 112-8681 Japan
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26
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Gerber E, Hemmerlin A, Hartmann M, Heintz D, Hartmann MA, Mutterer J, Rodríguez-Concepción M, Boronat A, Van Dorsselaer A, Rohmer M, Crowell DN, Bach TJ. The plastidial 2-C-methyl-D-erythritol 4-phosphate pathway provides the isoprenyl moiety for protein geranylgeranylation in tobacco BY-2 cells. THE PLANT CELL 2009; 21:285-300. [PMID: 19136647 PMCID: PMC2648074 DOI: 10.1105/tpc.108.063248] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 12/12/2008] [Accepted: 12/19/2008] [Indexed: 05/07/2023]
Abstract
Protein farnesylation and geranylgeranylation are important posttranslational modifications in eukaryotic cells. We visualized in transformed Nicotiana tabacum Bright Yellow-2 (BY-2) cells the geranylgeranylation and plasma membrane localization of GFP-BD-CVIL, which consists of green fluorescent protein (GFP) fused to the C-terminal polybasic domain (BD) and CVIL isoprenylation motif from the Oryza sativa calmodulin, CaM61. Treatment with fosmidomycin (Fos) or oxoclomazone (OC), inhibitors of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, caused mislocalization of the protein to the nucleus, whereas treatment with mevinolin, an inhibitor of the cytosolic mevalonate pathway, did not. The nuclear localization of GFP-BD-CVIL in the presence of MEP pathway inhibitors was completely reversed by all-trans-geranylgeraniol (GGol). Furthermore, 1-deoxy-d-xylulose (DX) reversed the effects of OC, but not Fos, consistent with the hypothesis that OC blocks 1-deoxy-d-xylulose 5-phosphate synthesis, whereas Fos inhibits its conversion to 2-C-methyl-d-erythritol 4-phosphate. By contrast, GGol and DX did not rescue the nuclear mislocalization of GFP-BD-CVIL in the presence of a protein geranylgeranyltransferase type 1 inhibitor. Thus, the MEP pathway has an essential role in geranylgeranyl diphosphate (GGPP) biosynthesis and protein geranylgeranylation in BY-2 cells. GFP-BD-CVIL is a versatile tool for identifying pharmaceuticals and herbicides that interfere either with GGPP biosynthesis or with protein geranylgeranylation.
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Affiliation(s)
- Esther Gerber
- Institut de Biologie Moléculaire des Plantes (Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357, associated with the Université Louis Pasteur), F-67083 Strasbourg, France
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27
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Huizinga DH, Omosegbon O, Omery B, Crowell DN. Isoprenylcysteine methylation and demethylation regulate abscisic acid signaling in Arabidopsis. THE PLANT CELL 2008; 20:2714-28. [PMID: 18957507 PMCID: PMC2590716 DOI: 10.1105/tpc.107.053389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Isoprenylated proteins bear an isoprenylcysteine methyl ester at the C terminus. Although isoprenylated proteins have been implicated in meristem development and negative regulation of abscisic acid (ABA) signaling, the functional role of the terminal methyl group has not been described. Here, we show that transgenic Arabidopsis thaliana plants overproducing isoprenylcysteine methyltransferase (ICMT) exhibit ABA insensitivity in stomatal closure and seed germination assays, establishing ICMT as a negative regulator of ABA signaling. By contrast, transgenic plants overproducing isoprenylcysteine methylesterase (ICME) exhibit ABA hypersensitivity in stomatal closure and seed germination assays. Thus, ICME is a positive regulator of ABA signaling. To test the hypothesis that ABA signaling is under feedback regulation at the level of isoprenylcysteine methylation, we examined the effect of ABA on ICMT and ICME gene expression. Interestingly, ABA induces ICME gene expression, establishing a positive feedback loop whereby ABA promotes ABA responsiveness of plant cells via induction of ICME expression, which presumably results in the demethylation and inactivation of isoprenylated negative regulators of ABA signaling. These results suggest strategies for metabolic engineering of crop species for drought tolerance by targeted alterations in isoprenylcysteine methylation.
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Affiliation(s)
- David H Huizinga
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202-5132, USA
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28
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Towler MJ, Weathers PJ. Evidence of artemisinin production from IPP stemming from both the mevalonate and the nonmevalonate pathways. PLANT CELL REPORTS 2007; 26:2129-36. [PMID: 17710406 DOI: 10.1007/s00299-007-0420-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 06/29/2007] [Accepted: 07/19/2007] [Indexed: 05/03/2023]
Abstract
The potent antimalarial sesquiterpene lactone, artemisinin, is produced in low quantities by the plant Artemisia annua L. The source and regulation of the isopentenyl diphosphate (IPP) used in the biosynthesis of artemisinin has not been completely characterized. Terpenoid biosynthesis occurs in plants via two IPP-generating pathways: the mevalonate pathway in the cytosol, and the non-mevalonate pathway in plastids. Using inhibitors specific to each pathway, it is possible to resolve which supplies the IPP precursor to the end product. Here, we show the effects of inhibition on the two pathways leading to IPP for artemisinin production in plants. We grew young (7-14 days post cotyledon) plants in liquid culture, and added mevinolin to the medium to inhibit the mevalonate pathway, or fosmidomycin to inhibit the non-mevalonate pathway. Artemisinin levels were measured after 7-14 days incubation, and production was significantly reduced by each inhibitor compared to controls, thus, it appears that IPP from both pathways is used in artemisinin production. Also when grown in miconazole, an inhibitor of sterol biosynthesis, there was a significant increase in artemisinin compared to controls suggesting that carbon was shifted from sterols into sesquiterpenes. Collectively these results indicate that artemisinin is probably biosynthesized from IPP pools from both the plastid and the cytosol, and that carbon from competing pathways can be channeled toward sesquiterpenes. This information will help advance our understanding of the regulation of in planta production of artemisinin.
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Affiliation(s)
- Melissa J Towler
- Department of Biology/Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
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29
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Ohyama K, Suzuki M, Masuda K, Yoshida S, Muranaka T. Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis. Chem Pharm Bull (Tokyo) 2007; 55:1518-21. [DOI: 10.1248/cpb.55.1518] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | | | | | - Toshiya Muranaka
- RIKEN Plant Science Center
- Kihara Institute for Biological Research, Yokohama City University
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30
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Hemmerlin A, Reents R, Mutterer J, Feldtrauer JF, Waldmann H, Bach TJ. Monitoring farnesol-induced toxicity in tobacco BY-2 cells with a fluorescent analog. Arch Biochem Biophys 2006; 448:93-103. [PMID: 16307722 DOI: 10.1016/j.abb.2005.10.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 09/28/2005] [Accepted: 10/02/2005] [Indexed: 11/16/2022]
Abstract
In a previous study (A. Hemmerlin, T.J. Bach, Plant Physiol. 123 (2000) 1257-1268), we have demonstrated that above a critical concentration, treatment with all-trans-farnesol induces cell-death in Nicotiana tabacum L. cv Bright Yellow-2 (TBY-2) cells. Now we used a fluorescent analog of farnesol (Fol(FLUO)), in which an isoprene unit is replaced by the fluorochrome 7-nitrobenz-2-oxa-1,3-diazol-4-yl, to visualize how cell integrity is affected. Fol(FLUO) exhibited the same toxicity as the natural compound and was shown to be readily taken up by TBY-2 cells, followed by integration into subcellular membrane structures. Although the plasma membrane seemed not to be labeled, Fol(FLUO) was associated with the tonoplast, endoplasmic reticulum, and Golgi apparatus or lipid bodies. Longer exposure times and increased Fol(FLUO) accumulation triggered the formation and proliferation of new membrane structures of as yet unknown function. Finally, at even higher and clearly cytotoxic concentrations of the analog, the cell contents became clearly disorganized, with cell swelling and ultimately plasmolysis.
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Affiliation(s)
- Andréa Hemmerlin
- C.N.R.S., Institut de Biologie Moléculaire des Plantes, Département Isoprénoïdes, Université Louis Pasteur, 28 rue Goethe, F-67083 Strasbourg, France
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31
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Espunya MC, López-Giráldez T, Hernan I, Carballo M, Martínez MC. Differential expression of genes encoding protein kinase CK2 subunits in the plant cell cycle. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:3183-92. [PMID: 16263904 DOI: 10.1093/jxb/eri315] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Protein kinase CK2 is a ubiquitous Ser/Thr/Tyr kinase essential for cell viability in eukaryotes. It comprises alpha catalytic and beta regulatory subunits, which combine to form the classical tetrameric structure, alpha2beta2. Although CK2 is a component of the network that controls the eukaryotic cell cycle, very little is known about the expression patterns of genes encoding its constituent subunits, especially in plants. A study of the complexity of CK2alpha- and CK2beta-encoding genes in BY-2 cells was undertaken in this work, and cloning of the different members of the gene families was performed. The expression of the individual members of each family in relation to cell proliferation was measured by real time RT-PCR. The data obtained provide an accurate understanding of the transcriptional regulation of CK2 in relation to the cell cycle and cell proliferation.
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Affiliation(s)
- M Carme Espunya
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Barcelona, E-08193 Bellaterra (Barcelona), Spain
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32
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Nagegowda DA, Ramalingam S, Hemmerlin A, Bach TJ, Chye ML. Brassica juncea HMG-CoA synthase: localization of mRNA and protein. PLANTA 2005; 221:844-56. [PMID: 15770484 DOI: 10.1007/s00425-005-1497-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 01/29/2005] [Indexed: 05/24/2023]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme-A (HMG-CoA) synthase (HMGS; EC 2.3.3.10) synthesizes HMG-CoA, a substrate for mevalonate biosynthesis in the isoprenoid pathway. It catalyzes the condensation of acetyl-CoA with acetoacetyl-CoA (AcAc-CoA) to yield S-HMG-CoA and HS-CoA. In Brassica juncea (Indian mustard), HMGS is encoded by four isogenes (BjHMGS1-BjHMGS4). We have already enzymatically characterized recombinant BjHMGS1 expressed in Escherichia coli, and have identified its residues that are significant in catalysis. To further study HMGS mRNA expression that is developmentally regulated in flowers and seedlings, we have examined its mRNA distribution by in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR). We observed predominant localization of HMGS mRNA in the stigmas and ovules of flower buds and in the piths of seedling hypocotyls. RT-PCR analysis revealed that BjHMGS1 and BjHMGS2 but not BjHMGS3 and BjHMGS4were expressed in floral buds. To investigate the subcellular localization of BjHMGS1, we fused BjHMGS1 translationally in-frame either to the N- or C-terminus of green fluorescent protein (GFP). BjHMGS1-GFP and GFP-BjHMGS1 fusions were used in particle gun bombardment of onion epidermal cells and tobacco BY-2 cells. The GFP-BjHMGS1 construct was also used in agroinfiltration of tobacco leaves. Both GFP-fusion proteins were observed transiently expressed in the cytosol on confocal microscopy of onion epidermal cells, tobacco BY-2 cells, and agroinfiltrated tobacco leaves. Further, subcellular fractionation of total proteins from transgenic plants expressing GFP-BjHMGS1 derived from Agrobacterium-mediated transformation confirmed that BjHMGS1 is a cytosolic enzyme. We suggest that the presence of BjHMGS isoforms is likely related to the specialization of each in different cellular and metabolic processes rather than to a different intracellular compartmentation of the enzyme.
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Affiliation(s)
- Dinesh A Nagegowda
- Department of Botany, The University of Hong Kong, Pokfulam, Hong Kong, China
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Nagegowda D, Bach T, Chye ML. Brassica juncea 3-hydroxy-3-methylglutaryl (HMG)-CoA synthase 1: expression and characterization of recombinant wild-type and mutant enzymes. Biochem J 2005; 383:517-27. [PMID: 15233626 PMCID: PMC1133745 DOI: 10.1042/bj20040721] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
3-hydroxy-3-methylglutaryl (HMG)-CoA synthase (HMGS; EC 2.3.3.10) is the second enzyme in the cytoplasmic mevalonate pathway of isoprenoid biosynthesis, and catalyses the condensation of acetyl-CoA with acetoacetyl-CoA (AcAc-CoA) to yield S-HMG-CoA. In this study, we have first characterized in detail a plant HMGS, Brassica juncea HMGS1 (BjHMGS1), as a His6-tagged protein from Escherichia coli. Native gel electrophoresis analysis showed that the enzyme behaves as a homodimer with a calculated mass of 105.8 kDa. It is activated by 5 mM dithioerythreitol and is inhibited by F-244 which is specific for HMGS enzymes. It has a pH optimum of 8.5 and a temperature optimum of 35 degrees C, with an energy of activation of 62.5 J x mol(-1). Unlike cytosolic HMGS from chicken and cockroach, cations like Mg2+, Mn2+, Zn2+ and Co2+ did not stimulate His6-BjHMGS1 activity in vitro; instead all except Mg2+ were inhibitory. His6-BjHMGS1 has an apparent K(m-acetyl-CoA) of 43 microM and a V(max) of 0.47 micromol x mg(-1) x min(-1), and was inhibited by one of the substrates (AcAc-CoA) and by both products (HMG-CoA and HS-CoA). Site-directed mutagenesis of conserved amino acid residues in BjHMGS1 revealed that substitutions R157A, H188N and C212S resulted in a decreased V(max), indicating some involvement of these residues in catalytic capacity. Unlike His6-BjHMGS1 and its soluble purified mutant derivatives, the H188N mutant did not display substrate inhibition by AcAc-CoA. Substitution S359A resulted in a 10-fold increased specific activity. Based on these kinetic analyses, we generated a novel double mutation H188N/S359A, which resulted in a 10-fold increased specific activity, but still lacking inhibition by AcAc-CoA, strongly suggesting that His-188 is involved in conferring substrate inhibition on His6-BjHMGS1. Substitution of an aminoacyl residue resulting in loss of substrate inhibition has never been previously reported for any HMGS.
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Affiliation(s)
- Dinesh A. Nagegowda
- *Department of Botany, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Thomas J. Bach
- †Centre National de la Recherche Scientifique, UPR 2357, Institut de Biologie. Moléculaire des Plantes, 28 rue Goethe, 67083 Strasbourg Cedex, France
| | - Mee-Len Chye
- *Department of Botany, The University of Hong Kong, Pokfulam, Hong Kong, China
- To whom correspondence should be addressed (email )
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Hemmerlin A, Gerber E, Feldtrauer JF, Wentzinger L, Hartmann MA, Tritsch D, Hoeffler JF, Rohmer M, Bach TJ. A review of tobacco BY-2 cells as an excellent system to study the synthesis and function of sterols and other isoprenoids. Lipids 2004; 39:723-35. [PMID: 15638240 DOI: 10.1007/s11745-004-1289-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate (IPP), the universal precursor for isoprenoid biosynthesis. In this paper we review findings and observations made primarily with tobacco BY-2 cells (TBY-2), which have proven to be an excellent system in which to study the two biosynthetic pathways. A major advantage of these cells as an experimental system is their ability to readily take up specific inhibitors and stably- and/or radiolabeled precursors. This permits the functional elucidation of the role of isoprenoid end products and intermediates. Because TBY-2 cells undergo rapid cell division and can be synchronized within the cell cycle, they constitute a highly suitable test system for determination of those isoprenoids and intermediates that act as cell cycle inhibitors, thus giving an indication of which branches of the isoprenoid pathway are essential. Through chemical complementation; and use of precursors, intracellular compartmentation can be elucidated, as well as the extent to which the plastidial and cytosolic pathways contribute to the syntheses of specific groups of isoprenoids (e.g., sterols) via exchange of intermediates across membranes. These topics are discussed in the context of the pertinent literature.
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Affiliation(s)
- Andréa Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (UPR 2357), Département Fonctions et Biosynthèse des Isoprénoïdes, Université Louis Pasteur, F-67083 Strasbourg, France
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Suzuki M, Kamide Y, Nagata N, Seki H, Ohyama K, Kato H, Masuda K, Sato S, Kato T, Tabata S, Yoshida S, Muranaka T. Loss of function of 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 (HMG1) in Arabidopsis leads to dwarfing, early senescence and male sterility, and reduced sterol levels. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:750-761. [PMID: 14871314 DOI: 10.1111/j.1365-313x.2004.02003.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the first committed step in the cytosolic isoprenoid biosynthesis pathway in higher plants. To understand the contribution of HMGR to plant development, we isolated T-DNA insertion mutants for HMG1 and HMG2. The hmg1 and hmg2 mutants were both more sensitive than the wild type (WT) to lovastatin, an inhibitor of HMGR. The hmg2 mutant showed no visible phenotype under normal growth conditions. In contrast, the hmg1 mutant exhibited dwarfing, early senescence, and sterility. Expression of senescence-associated genes 12 (SAG12), a marker gene for senescence, was induced in the hmg1 mutant at an earlier stage than in the WT. Levels of trans-cytokinins--hormones known to inhibit senescence--were not lower in hmg1. The mutant did not have the typical appearance of brassinosteroid (BR)-deficient mutants, except for a dwarf phenotype, because of the suppression of cell elongation. The expression of several genes involved in cell elongation was suppressed in hmg1. WT plants treated exogenously with inhibitors of sterol biosynthesis had similar gene expression and sterility characteristics as the hmg1 mutants. Pleiotropic phenotypes were rescued by feeding with squalene, the precursor of sterols and triterpenoids. The sterol levels in hmg1 mutants were lower than in the WT. These findings suggest that HMG1 plays a critical role in triterpene biosynthesis, and that sterols and/or triterpenoids contribute to cell elongation, senescence, and fertility.
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Affiliation(s)
- Masashi Suzuki
- Plant Science Center, RIKEN, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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Hemmerlin A, Hoeffler JF, Meyer O, Tritsch D, Kagan IA, Grosdemange-Billiard C, Rohmer M, Bach TJ. Cross-talk between the cytosolic mevalonate and the plastidial methylerythritol phosphate pathways in tobacco bright yellow-2 cells. J Biol Chem 2003; 278:26666-76. [PMID: 12736259 DOI: 10.1074/jbc.m302526200] [Citation(s) in RCA: 252] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate, the universal precursor for isoprenoid biosynthesis. The key enzyme of the cytoplasmic mevalonic acid (MVA) pathway is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). Treatment of Tobacco Bright Yellow-2 (TBY-2) cells by the HMGR-specific inhibitor mevinolin led to growth reduction and induction of apparent HMGR activity, in parallel to an increase in protein representing two HMGR isozymes. Maximum induction was observed at 24 h. 1-Deoxy-d-xylulose (DX), the dephosphorylated first precursor of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, complemented growth inhibition by mevinolin in the low millimolar concentration range. Furthermore, DX partially re-established feedback repression of mevinolin-induced HMGR activity. Incorporation studies with [1,1,1,4-2H4]DX showed that sterols, normally derived from MVA, in the presence of mevinolin are synthesized via the MEP pathway. Fosmidomycin, an inhibitor of 1-deoxy-d-xylulose-5-phosphate reductoisomerase, the second enzyme of the MEP pathway, was utilized to study the reverse complementation. Growth inhibition by fosmidomycin of TBY-2 cells could be partially overcome by MVA. Chemical complementation was further substantiated by incorporation of [2-13C]MVA into plastoquinone, representative of plastidial isoprenoids. Best rates of incorporation of exogenous stably labeled precursors were observed in the presence of both inhibitors, thereby avoiding internal isotope dilution.
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Affiliation(s)
- Andréa Hemmerlin
- CNRS, UPR 2357, Institut de Biologie Moléculaire des Plantes, 28 Rue Goethe, 67083 Strasbourg Cedex, France
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Miyazawa Y, Kato H, Muranaka T, Yoshida S. Amyloplast formation in cultured tobacco BY-2 cells requires a high cytokinin content. PLANT & CELL PHYSIOLOGY 2002; 43:1534-41. [PMID: 12514251 DOI: 10.1093/pcp/pcf173] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
When cytokinin-autonomous tobacco BY-2 cell cultures are transferred into 2,4-dichlorophenoxyacetic acid (2,4-D)-deprived medium, amyloplast development is initiated. Using this in vitro amyloplast-inducing system, the role of cytokinins in amyloplast formation was investigated. We show that addition of lovastatin, an inhibitor of mevalonate synthesis, to amyloplast-inducing medium reduced starch accumulation. Microscopic observation also revealed that lovastatin treatment decreased starch deposition; however, the overall morphologies of cells and plastids were less affected than control cell cultures. In addition, lovastatin lowered the transcription level of the ADP-glucose pyrophosphorylase small subunit (AgpS) gene. Application of mevalonate or zeatin dramatically restored the decrease in starch deposition, and restored AgpS mRNA accumulation. Moreover, addition of other molecules with cytokinin activity, such as adenine- and phenylurea-type compounds, restored starch accumulation and AgpS transcript levels, whereas other isopentenyl pyrophosphate-derived phytohormones did not. Liquid chromatography-mass spectrometry/mass spectrometry quantification of endogenous cytokinins revealed that endogenous cytokinins increased when BY-2 cells were transferred into 2,4-D-deprived medium from conventional medium containing 2,4-D. In addition, lovastatin treatment decreased endogenous cytokinins to some extent when cultured under 2,4-D-deprived conditions. Our results suggest that both 2,4-D deprivation and an increase in endogenous cytokinins have important roles in accelerating the changes in plastid morphology, starch accumulation, and AgpS gene expression.
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Affiliation(s)
- Yutaka Miyazawa
- Plant Functions Laboratory, RIKEN, 2-1, Hirosawa, Wako, Saitama, 351-0198 Japan.
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Shindia AA. Some nutritional factors influencing mevinolin production by Aspergillus terreus strain. Folia Microbiol (Praha) 2002; 46:413-6. [PMID: 11899474 DOI: 10.1007/bf02814431] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Aspergillus terreus produces the hypocholesterolemic compound mevinolin. Its growth and mevinolin production were affected by the composition of the culture medium. Both were at a maximum with glucose (6%) as the sole carbon source and in the presence of a mixture of yeast extract and sodium nitrate as nitrogen source. Influence of the concentration of some inorganic salts are also discussed.
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Affiliation(s)
- A A Shindia
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig, Egypt
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Hoeffler JF, Hemmerlin A, Grosdemange-Billiard C, Bach TJ, Rohmer M. Isoprenoid biosynthesis in higher plants and in Escherichia coli: on the branching in the methylerythritol phosphate pathway and the independent biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate. Biochem J 2002; 366:573-83. [PMID: 12010124 PMCID: PMC1222787 DOI: 10.1042/bj20020337] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2002] [Revised: 04/26/2002] [Accepted: 05/15/2002] [Indexed: 11/17/2022]
Abstract
In the bacterium Escherichia coli, the mevalonic-acid (MVA)-independent 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway is characterized by two branches leading separately to isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The signature of this branching is the retention of deuterium in DMAPP and the deuterium loss in IPP after incorporation of 1-[4-(2)H]deoxy-d-xylulose ([4-(2)H]DX). Feeding tobacco BY-2 cell-suspension cultures with [4-(2)H]DX resulted in deuterium retention in the isoprene units derived from DMAPP, as well as from IPP in the plastidial isoprenoids, phytoene and plastoquinone, synthesized via the MEP pathway. This labelling pattern represents direct evidence for the presence of the DMAPP branch of the MEP pathway in a higher plant, and shows that IPP can be synthesized from DMAPP in plant plastids, most probably via a plastidial IPP isomerase.
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Affiliation(s)
- Jean-François Hoeffler
- Université Louis Pasteur/CNRS, Institut Le Bel, 4 rue Blaise Pascal, 67070 Strasbourg cedex, France
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Houot V, Etienne P, Petitot AS, Barbier S, Blein JP, Suty L. Hydrogen peroxide induces programmed cell death features in cultured tobacco BY-2 cells, in a dose-dependent manner. JOURNAL OF EXPERIMENTAL BOTANY 2001. [PMID: 11479338 DOI: 10.1093/jxb/52.361.1721] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Active oxygen species (AOS), especially hydrogen peroxide, play a critical role in the defence of plants against invading pathogens and in the hypersensitive response (HR). This is characterized by the induction of a massive production of AOS and the rapid appearance of necrotic lesions is considered as a programmed cell death (PCD) process during which a limited number of cells die at the site of infection. This work was aimed at investigating the mode of cell death observed in cultures of BY-2 tobacco cells exposed to H(2)O(2). It was shown that H(2)O(2) is able to induce various morphological cell death features in cultured tobacco BY-2 cells. The hallmarks of cell death observed with fluorescent and electron microscopy differed greatly with the amount of H(2)O(2) added to the cell culture. The appearance of nuclear fragmentation similar to 'apoptotic bodies' associated with a fragmentation of the nuclear DNA into small fragments appear for almost 18% of the cells treated with 12.5 mM H(2)O(2). The early stages of the induction of this PCD process consisted in cell shrinkage and chromatin condensation at the periphery of the nucleus. Above 50 mM, H(2)O(2) induces high necrotic cell death. These data suggest that H(2)O(2)-induced cell damage is associated with the induction of various cell death processes that could be involved differently in plant defence reactions.
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Affiliation(s)
- V Houot
- UMR INRA-Université de Bourgogne, Phytopharmacie et Biochimie des Interactions Cellulaires, INRA BP 86510, 21065 Dijon cedex, France
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Hemmerlin A, Bach TJ. Farnesol-induced cell death and stimulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in tobacco cv bright yellow-2 cells. PLANT PHYSIOLOGY 2000; 123:1257-68. [PMID: 10938345 PMCID: PMC59085 DOI: 10.1104/pp.123.4.1257] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2000] [Accepted: 02/21/2000] [Indexed: 05/20/2023]
Abstract
Growth inhibition of tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells by mevinolin, a specific inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) could be partially overcome by the addition of farnesol. However, farnesol alone inhibited cell division and growth as measured by determination of fresh weight increase. When 7-d-old tobacco cv Bright Yellow-2 cells were diluted 40-fold into fresh culture, the cells exhibited a dose-dependent sensitivity to farnesol, with 25 microM sufficient to cause 100% cell death, as measured by different staining techniques, cytometry, and monitoring of fragmentation of genomic DNA. Cells were less sensitive to the effects of farnesol when diluted only 4-fold. Farnesol was absorbed by the cells, as examined by [1-(3)H]farnesol uptake, with a greater relative enrichment by the more diluted cells. Both mevinolin and farnesol treatments stimulated apparent HMGR activity. The stimulation by farnesol was also reflected in corresponding changes in the steady-state levels of HMGR mRNA and enzyme protein with respect to HMGR gene expression and enzyme protein accumulation.
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Affiliation(s)
- A Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, Département Isoprénoïdes, Institut de Botanique, Université Louis Pasteur, 28 rue Goethe, F-67083 Strasbourg, France
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Korth KL, Jaggard DA, Dixon RA. Developmental and light-regulated post-translational control of 3-hydroxy-3-methylglutaryl-CoA reductase levels in potato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 23:507-516. [PMID: 10972877 DOI: 10.1046/j.1365-313x.2000.00821.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In plants, the first committed step in the cytosolic pathway for biosynthesis of isoprenoids is catalysed by 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR). We have added an eight amino-acid-residue epitope tag to a potato (Solanum tuberosum L.) HMGR isoform and expressed this novel protein (HMGR-FLAG) in transgenic plants. Despite high levels of transcript accumulation in all leaf stages of transgenic plants, high levels of HMGR-FLAG protein were found only in apical meristematic tissue, suggesting post-translational regulation of potato HMGR affected by plant development. Protein immunoblots, and determination of enzymatic activity and transcript accumulation in the HMGR-FLAG transgenic and the non-transgenic parental plant lines, show that HMGR levels decrease dramatically in the dark. Again, the mechanism of this control occurs at a post-translational level. After 2.5 h in darkness, levels of HMGR-FLAG are approximately one-half of those in plants in the light; protein levels recover rapidly when dark-treated plants are returned to the light. In non-transgenic plants, hmg transcript levels are reduced in the dark, whereas dark treatments do not affect transgene hmg transcripts expressed under the control of a constitutive promoter. Furthermore, transcripts for HMGR-FLAG remain associated with polyribosomes in dark-treated tissues. Addition of inhibitors of cysteine proteases during microsomal protein extraction is required for recovery of immunoreactive HMGR-FLAG. The epitope-tagged isozyme has been used to show for the first time that a regulated decrease in plant HMGR activity correlates closely with a loss of the HMGR protein. We have used whole plants to demonstrate that developmental and light-regulated control of HMGR occurs post-translationally in vivo.
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Affiliation(s)
- K L Korth
- Department of Plant Pathology, 217 Plant Science Building, University of Arkansas, Fayetteville, AR 72701, USA.
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Alex D, Bach TJ, Chye ML. Expression of Brassica juncea 3-hydroxy-3-methylglutaryl CoA synthase is developmentally regulated and stress-responsive. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 22:415-426. [PMID: 10849357 DOI: 10.1046/j.1365-313x.2000.00751.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS) is an enzyme in mevalonate biosynthesis. In plants, investigations have focused on HMG CoA reductase (HMGR) and less is known of the preceding enzyme, HMGS. To understand the regulation of HMGS, we have isolated a Brassica juncea cDNA encoding HMGS, BjHMGS1, for use as a hybridization probe in Northern blot analyses. BjHMGS is expressed in all plant organs and shows developmental regulation in flower, seed and seedling, with highest expression in early development. In seedlings, expression is highest in young hypocotyls and is induced during the greening of etiolated cotyledons. BjHMGS is down-regulated by abscisic acid, osmotic stress and dehydration, the effects of which arrested seedling growth. Thus BjHMGS expression shows correlation with rapid cell division and growth, like HMGR. This is not unexpected, as mevalonate is the precursor to many essential isoprenoid compounds, including sterols for membrane biogenesis. Wounding, methyl jasmonate or salicylic acid induce BjHMGS expression, suggesting that, like HMGR, HMGS is involved in defence. As in animals, coordinated regulation of HMGS with HMGR occurred in B. juncea upon germination and in response to salicylic acid. HMGS assays confirmed that Escherichia coli-expressed recombinant BjHMGS1 shows HMGS activity that is inhibited by F244, a specific inhibitor of HMGS. Southern blot analysis revealed gene families encoding HMGS in Brassica species and a summation of homologous genes in the fusion amphidiploid genome of B. juncea, a bi-parental species derived from diploids B. nigra and B. campestris.
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Affiliation(s)
- D Alex
- Department of Botany, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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Laureys F, Smets R, Lenjou M, Van Bockstaele D, Inzé D, Van Onckelen H. A low content in zeatin type cytokinins is not restrictive for the occurrence of G1/S transition in tobacco BY-2 cells. FEBS Lett 1999; 460:123-8. [PMID: 10571073 DOI: 10.1016/s0014-5793(99)01264-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Theories on the importance of cytokinins in G1/S transition control are manifold and contradictory. By establishing a double A(phi-PZ block, maximal synchronization of a BY-2 suspension culture was obtained to investigate the effect of cytokinin depletion on G1/S transition. Lovastatin was used as a specific inhibitor of cytokinin biosynthesis. Flow cytometry showed that the G1/S transition occurred regardless of the cytokinin drop. This observation indicates an extremely low dose requiry for that stage of the cell cycle. It is very likely that precisely the downregulation of zeatin type cytokinins matters for the G1/S transition to occur, since cytokinin addition at early G1 blocked the cycle at G1/S.
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Affiliation(s)
- F Laureys
- Department of Biology, Universiteit Antwerpen, Wilrijk, Belgium
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