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Cupp JD, Nielsen BL. Arabidopsis thaliana organellar DNA polymerase IB mutants exhibit reduced mtDNA levels with a decrease in mitochondrial area density. PHYSIOLOGIA PLANTARUM 2013; 149:91-103. [PMID: 23167278 DOI: 10.1111/ppl.12009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/31/2012] [Accepted: 10/31/2012] [Indexed: 05/04/2023]
Abstract
Plant organelle genomes are complex and the mechanisms for their replication and maintenance remain unclear. Arabidopsis thaliana has two DNA polymerase genes, DNA polymerase IA (polIA) and polIB, that are dual targeted to mitochondria and chloroplasts and are differentially expressed in primary plant tissues. PolIB gene expression occurs at higher levels in tissues not primary for photosynthesis. Arabidopsis T-DNA polIB mutants have a 30% reduction in relative mitochondrial DNA (mtDNA) levels, but also exhibit a 70% increase in polIA gene expression. The polIB mutant shows an increase in mitochondrial numbers but a significant decrease in mitochondrial area density within the hypocotyl epidermis, shoot apex and root tips. Chloroplast numbers are not significantly different in mesophyll protoplasts. These mutants do not have a significant difference in total dark mitorespiration levels but exhibit a difference in light respiration levels and photosynthesis capacity. Organelle-encoded genes for components of respiration and photosynthesis are upregulated in polIB mutants. The mutants exhibited slow growth in conjunction with a decreased rate of cell expansion and other secondary phenotypic effects. Evidence suggests that early plastid development and DNA levels are directly affected by a polIB mutation but are resolved to wild-type levels over time. However, mitochondria numbers and DNA levels never reach wild-type levels in the polIB mutant. We propose that both polIA and polIB are required for mtDNA replication. The results suggest that polIB mutants undergo an adjustment in cell homeostasis, enabling them to maintain functional mitochondria at the cost of normal cell expansion and plant growth.
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Affiliation(s)
- John D Cupp
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
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52
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Kwasniak M, Majewski P, Skibior R, Adamowicz A, Czarna M, Sliwinska E, Janska H. Silencing of the nuclear RPS10 gene encoding mitochondrial ribosomal protein alters translation in arabidopsis mitochondria. THE PLANT CELL 2013; 25:1855-67. [PMID: 23723321 PMCID: PMC3694710 DOI: 10.1105/tpc.113.111294] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hardly anything is known about translational control of plant mitochondrial gene expression. Here, we provide evidence for differential translation of mitochondrial transcripts in Arabidopsis thaliana. We found that silencing of the nuclear RPS10 gene encoding mitochondrial ribosomal protein S10 disturbs the ratio between the small and large subunits of mitoribosomes, with an excess of the latter. Moreover, a portion of the small subunits are incomplete, lacking at least the S10 protein. rps10 cells also have an increased mitochondrial DNA copy number per cell, causing an upregulation of all mitochondrial transcripts. Mitochondrial translation is also altered so that it largely overrides the hyperaccumulation of transcripts, and as a consequence, only ribosomal proteins are oversynthesized, whereas oxidative phosphorylation subunits are downregulated. Expression of nuclear-encoded components of mitoribosomes and oxidative phosphorylation system (OXPHOS) complexes seems to be less affected. The ultimate coordination of expression of the nuclear and mitochondrial genomes occurs at the complex assembly level. These findings indicate that mitoribosomes can regulate gene expression by varying the efficiency of translation of mRNAs for OXPHOS and ribosomal proteins.
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Affiliation(s)
| | - Pawel Majewski
- Department of Biotechnology, University of Wroclaw, 51-148 Wroclaw, Poland
| | - Renata Skibior
- Department of Biotechnology, University of Wroclaw, 51-148 Wroclaw, Poland
| | | | - Malgorzata Czarna
- Department of Biotechnology, University of Wroclaw, 51-148 Wroclaw, Poland
| | - Elwira Sliwinska
- Department of Plant Genetics, Physiology, and Biotechnology, University of Technological and Life Sciences, 85-789 Bydgoszcz, Poland
| | - Hanna Janska
- Department of Biotechnology, University of Wroclaw, 51-148 Wroclaw, Poland
- Address correspondence to
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Duncan O, van der Merwe MJ, Daley DO, Whelan J. The outer mitochondrial membrane in higher plants. TRENDS IN PLANT SCIENCE 2013; 18:207-17. [PMID: 23291162 DOI: 10.1016/j.tplants.2012.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/29/2012] [Accepted: 12/05/2012] [Indexed: 05/11/2023]
Abstract
The acquisition and integration of intracellular organelles, such as mitochondria and plastids, were important steps in the emergence of complex multicellular life. Although the outer membranes of these organelles have lost many of the functions of their free-living bacterial ancestor, others were acquired during organellogenesis. To date, the biological roles of these proteins have not been systematically characterized. In this review, we discuss the evolutionary origins and functions of outer membrane mitochondrial (OMM) proteins in Arabidopsis thaliana. Our analysis, using phylogenetic inference, indicates that several OMM proteins either acquired novel functional roles or were recruited from other subcellular localizations during evolution in Arabidopsis. These observations suggest the existence of novel communication routes and functions between organelles within plant cells.
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Affiliation(s)
- Owen Duncan
- ARC Centre of Excellence in Plant Energy Biology, MCS Building M316, University of Western Australia, Crawley, WA 6009, Australia
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55
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Zhang B, Carrie C, Ivanova A, Narsai R, Murcha MW, Duncan O, Wang Y, Law SR, Albrecht V, Pogson B, Giraud E, Van Aken O, Whelan J. LETM proteins play a role in the accumulation of mitochondrially encoded proteins in Arabidopsis thaliana and AtLETM2 displays parent of origin effects. J Biol Chem 2012; 287:41757-73. [PMID: 23043101 PMCID: PMC3516725 DOI: 10.1074/jbc.m112.383836] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 10/01/2012] [Indexed: 11/06/2022] Open
Abstract
The Arabidopsis thaliana genome contains two genes with homology to the mitochondrial protein LETM1 (leucine zipper-EF-hand-containing transmembrane protein). Inactivation of both genes, Atletm1 and Atletm2, together is lethal. Plants that are hemizygous for AtLETM2 and homozygous for Atletm1 (letm1(-/-) LETM2(+/-)) displayed a mild retarded growth phenotype during early seedling growth. It was shown that accumulation of mitochondrial proteins was reduced in hemizygous (letm1(-/-) LETM2(+/-)) plants. Examination of respiratory chain proteins by Western blotting, blue native PAGE, and enzymatic activity assays revealed that the steady state level of ATP synthase was reduced in abundance, whereas the steady state levels of other respiratory chain proteins remained unchanged. The absence of a functional maternal AtLETM2 allele in an Atletm1 mutant background resulted in early seed abortion. Reciprocal crosses revealed that maternally, but not paternally, derived AtLETM2 was absolutely required for seed development. This requirement for a functional maternal allele of AtLETM2 was confirmed using direct sequencing of reciprocal crosses of Col-0 and Ler accessions. Furthermore, AtLETM2 promoter β-glucuronidase constructs displayed exclusive maternal expression patterns.
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Affiliation(s)
- Botao Zhang
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Chris Carrie
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Aneta Ivanova
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Reena Narsai
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
- Centre for Computational Systems Biology, Bayliss Building M316 University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia and
| | - Monika W. Murcha
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Owen Duncan
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Yan Wang
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Simon R. Law
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Verónica Albrecht
- the Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton 2601, Australian Capital Territory, Australia
| | - Barry Pogson
- the Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton 2601, Australian Capital Territory, Australia
| | - Estelle Giraud
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - Olivier Van Aken
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
| | - James Whelan
- From the Australian Research Council Centre of Excellence in Plant Energy Biology and
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Duchêne AM, Giegé P. Dual localized mitochondrial and nuclear proteins as gene expression regulators in plants? FRONTIERS IN PLANT SCIENCE 2012; 3:221. [PMID: 23056004 PMCID: PMC3457046 DOI: 10.3389/fpls.2012.00221] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 09/10/2012] [Indexed: 05/29/2023]
Abstract
Mitochondria heavily depend on the coordinated expression of both mitochondrial and nuclear genomes because some of their most significant activities are held by multi-subunit complexes composed of both mitochondrial and nuclear encoded proteins. Thus, precise communication and signaling pathways are believed to exist between the two compartments. Proteins dual localized to both mitochondria and the nucleus make excellent candidates for a potential involvement in the envisaged communication. Here, we review the identified instances of dual localized nucleo-mitochondrial proteins with an emphasis on plant proteins and discuss their functions, which are seemingly mostly related to gene expression regulation. We discuss whether dual localization could be achieved by dual targeting and/or by re-localization and try to apprehend the signals required for the respective processes. Finally, we propose that in some instances, dual localized mitochondrial and nuclear proteins might act as retrograde signaling molecules for mitochondrial biogenesis.
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Affiliation(s)
| | - Philippe Giegé
- *Correspondence: Philippe Giegé, Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, University of Strasbourg, 12 Rue du General Zimmer, 67084 Strasbourg, France. e-mail:
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57
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Comelli RN, Welchen E, Kim HJ, Hong JC, Gonzalez DH. Delta subclass HD-Zip proteins and a B-3 AP2/ERF transcription factor interact with promoter elements required for expression of the Arabidopsis cytochrome c oxidase 5b-1 gene. PLANT MOLECULAR BIOLOGY 2012; 80:157-167. [PMID: 22669746 DOI: 10.1007/s11103-012-9935-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/20/2012] [Indexed: 06/01/2023]
Abstract
We have identified transcription factors that interact with a promoter region involved in expression of the Arabidopsis thaliana COX5b-1 gene, which encodes an isoform of the cytochrome c oxidase zinc binding subunit. Elements with the core sequence ATCATT, involved in induction by sugars, are recognized both in vitro and in one-hybrid assays in yeast by HD-Zip proteins from the delta subclass and, though less efficiently, by the trihelix transcription factor GT-3b. DistalB-like elements (CCACTTG), required for induction by abscisic acid (ABA), interact with ESE1, a member of the B-3 subgroup of AP2/ERF transcription factors. The HD-Zip protein Athb-21 and ESE1 are able to interact in yeast two-hybrid assays with the ABA responsive element binding factor AREB2/ABF4, which binds to a G-box absolutely required for expression of the COX5b-1 gene. Overexpression of the identified transcription factors in plants produces an increase in COX5b-1 transcript levels. Moreover, these factors are able to induce the expression of a reporter gene located in plants under the control of the relevant COX5b-1 promoter regions required for expression. Analysis of promoter regions of COX5b genes from different plant species suggests that the identified transcription factors were recruited for the regulation of COX5b gene expression at different stages during the evolution of dicot plants.
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Affiliation(s)
- Raúl N Comelli
- Instituto de Agrobiotecnología del Litoral, Cátedra de Biología Celular y Molecular, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina
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58
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Li L, Carrie C, Nelson C, Whelan J, Millar AH. Accumulation of newly synthesized F1 in vivo in arabidopsis mitochondria provides evidence for modular assembly of the plant F1Fo ATP synthase. J Biol Chem 2012; 287:25749-57. [PMID: 22674576 DOI: 10.1074/jbc.m112.373506] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
F(1) subcomplex in mitochondrial samples is often considered to be a breakage product of the F(1)F(O) ATP synthase during sample handling and electrophoresis. We have used a progressive (15)N incorporation strategy to investigate the plant F(1)F(O) ATP synthase assembly model and the apparently free F(1) in plant mitochondria which is found in both the inner membrane and matrix. We show that subunits within F(1) in the inner membrane and matrix had a relatively higher (15)N incorporation rate than corresponding subunits in intact membrane F(1)F(O). This demonstrates that free F(1) was a newer pool with a faster turnover rate consistent with it being an assembly intermediate in vivo. Import of [(35)S]Met-labeled F(1) subunit precursors into Arabidopsis mitochondria showed the rapid accumulation of F(1) assembly intermediates. The different (15)N incorporation rate in matrix F(1), inner membrane F(1) and intact F(1)F(O) demonstrates these three represent different protein populations and are likely step by step intermediates during the assembly process of plant mitochondrial ATP synthase. The potential biological implications of in vivo accumulation of enzymatically active F(1) in mitochondria are discussed.
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Affiliation(s)
- Lei Li
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley WA 6009, Western Australia, Australia
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59
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Wang Y, Carrie C, Giraud E, Elhafez D, Narsai R, Duncan O, Whelan J, Murcha MW. Dual location of the mitochondrial preprotein transporters B14.7 and Tim23-2 in complex I and the TIM17:23 complex in Arabidopsis links mitochondrial activity and biogenesis. THE PLANT CELL 2012; 24:2675-95. [PMID: 22730406 PMCID: PMC3406907 DOI: 10.1105/tpc.112.098731] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Interactions between the respiratory chain and protein import complexes have been previously reported in Saccharomyces cerevisiae, but the biological significance of such interactions remains unknown. Characterization of two mitochondrial preprotein and amino acid transport proteins from Arabidopsis thaliana, NADH dehydrogenase B14.7 like (B14.7 [encoded by At2g42210]) and Translocase of the inner membrane subunit 23-2 (Tim23-2 [encoded by At1g72750]), revealed both proteins are present in respiratory chain complex I and the Translocase of the Inner Membrane 17:23. Whereas depletion of B14.7 by T-DNA insertion is lethal, Tim23-2 can be depleted without lethality. Subtle overexpression of Tim23-2 results in a severe delayed growth phenotype and revealed an unexpected, inverse correlation between the abundance of Tim23-2 and the abundance of respiratory complex I. This newly discovered relationship between protein import and respiratory function was confirmed through the investigation of independent complex I knockout mutants, which were found to have correspondingly increased levels of Tim23-2. This increase in Tim23-2 was also associated with delayed growth phenotypes, increased abundance of other import components, and an increased capacity for mitochondrial protein import. Analysis of the Tim23-2-overexpressing plants through global quantitation of transcript abundance and in-organelle protein synthesis assays revealed widespread alterations in transcript abundance of genes encoding mitochondrial proteins and altered rates of mitochondrial protein translation, indicating a pivotal relationship between the machinery of mitochondrial biogenesis and mitochondrial function.
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Affiliation(s)
- Yan Wang
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Chris Carrie
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Estelle Giraud
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Dina Elhafez
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Reena Narsai
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
- Centre for Computational Systems Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Owen Duncan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Monika W. Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
- Address correspondence to
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60
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Tan YF, Millar AH, Taylor NL. Components of mitochondrial oxidative phosphorylation vary in abundance following exposure to cold and chemical stresses. J Proteome Res 2012; 11:3860-79. [PMID: 22574745 DOI: 10.1021/pr3003535] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Plant mitochondria are highly responsive organelles that vary their metabolism in response to a wide range of chemical and environmental conditions. Quantitative proteomics studies have begun to allow the analysis of these large-scale protein changes in mitochondria. However studies of the integral membrane proteome of plant mitochondria, arguably the site responsible for the most fundamental mitochondrial processes of oxidative phosphorylation, protein import and metabolite transport, remain a technical challenge. Here we have investigated the changes in protein abundance in response to a number of chemical stresses and cold. In addition to refining the subcellular localization of 66 proteins, we have been able to characterize 596 protein × treatment combinations following a range of stresses. To date it has been assumed that the main mitochondrial response to stress involved the induction of alternative respiratory proteins such as AOX, UCPs, and alternative NAD(P)H dehydrogenases; we now provide evidence for a number of very specific protein abundance changes that have not been highlighted previously by transcript studies. This includes both previously characterized stress responsive proteins as well as major components of oxidative phosphorylation, protein import/export, and metabolite transport.
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Affiliation(s)
- Yew-Foon Tan
- ARC Centre of Excellence in Plant Energy Biology, MCS Building M316, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Western Australia, Australia
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61
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Welchen E, Hildebrandt TM, Lewejohann D, Gonzalez DH, Braun HP. Lack of cytochrome c in Arabidopsis decreases stability of Complex IV and modifies redox metabolism without affecting Complexes I and III. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:990-1001. [PMID: 22551905 DOI: 10.1016/j.bbabio.2012.04.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/09/2012] [Accepted: 04/11/2012] [Indexed: 12/12/2022]
Abstract
We studied the role of cytochrome c (CYTc), which mediates electron transfer between Complexes III and IV, in cellular events related with mitochondrial respiration, plant development and redox homeostasis. We analyzed single and double homozygous mutants in both CYTc-encoding genes from Arabidopsis: CYTC-1 and CYTC-2. While individual mutants were similar to wild-type, knock-out of both genes produced an arrest of embryo development, showing that CYTc function is essential at early stages of plant development. Mutants in which CYTc levels were extremely reduced respective to wild-type had smaller rosettes with a pronounced decrease in parenchymatic cell size and an overall delay in development. Mitochondria from these mutants had lower respiration rates and a relative increase in alternative respiration. Furthermore, the decrease in CYTc severely affected the activity and the amount of Complex IV, without affecting Complexes I and III. Reactive oxygen species levels were reduced in these mutants, which showed induction of genes encoding antioxidant enzymes. Ascorbic acid levels were not affected, suggesting that a small amount of CYTc is enough to support its normal synthesis. We postulate that, in addition to its role as an electron carrier between Complexes III and IV, CYTc influences Complex IV levels in plants, probably reflecting a role of this protein in Complex IV stability. This double function of CYTc most likely explains why it is essential for plant survival.
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Affiliation(s)
- Elina Welchen
- Instituto de Agrobiotecnología del Litoral (IAL), CONICET, Universidad Nacional del Litoral, Santa Fe, Argentina.
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62
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Law SR, Narsai R, Taylor NL, Delannoy E, Carrie C, Giraud E, Millar AH, Small I, Whelan J. Nucleotide and RNA metabolism prime translational initiation in the earliest events of mitochondrial biogenesis during Arabidopsis germination. PLANT PHYSIOLOGY 2012; 158:1610-27. [PMID: 22345507 PMCID: PMC3320173 DOI: 10.1104/pp.111.192351] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Accepted: 02/13/2012] [Indexed: 05/18/2023]
Abstract
Mitochondria play a crucial role in germination and early seedling growth in Arabidopsis (Arabidopsis thaliana). Morphological observations of mitochondria revealed that mitochondrial numbers, typical size, and oval morphology were evident after 12 h of imbibition in continuous light (following 48 h of stratification). The transition from a dormant to an active metabolic state was punctuated by an early molecular switch, characterized by a transient burst in the expression of genes encoding mitochondrial proteins. Factors involved in mitochondrial transcription and RNA processing were overrepresented among these early-expressed genes. This was closely followed by an increase in the transcript abundance of genes encoding proteins involved in mitochondrial DNA replication and translation. This burst in the expression of factors implicated in mitochondrial RNA and DNA metabolism was accompanied by an increase in transcripts encoding components required for nucleotide biosynthesis in the cytosol and increases in transcript abundance of specific members of the mitochondrial carrier protein family that have previously been associated with nucleotide transport into mitochondria. Only after these genes peaked in expression and largely declined were typical mitochondrial numbers and morphology observed. Subsequently, there was an increase in transcript abundance for various bioenergetic and metabolic functions of mitochondria. The coordination of nucleus- and organelle-encoded gene expression was also examined by quantitative reverse transcription-polymerase chain reaction, specifically for components of the mitochondrial electron transport chain and the chloroplastic photosynthetic machinery. Analysis of protein abundance using western-blot analysis and mass spectrometry revealed that for many proteins, patterns of protein and transcript abundance changes displayed significant positive correlations. A model for mitochondrial biogenesis during germination is proposed, in which an early increase in the abundance of transcripts encoding biogenesis functions (RNA metabolism and import components) precedes a later cascade of gene expression encoding the bioenergetic and metabolic functions of mitochondria.
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Affiliation(s)
| | | | | | | | | | | | | | | | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology (S.R.L., R.N., N.L.T., E.D., C.C., E.G., A.H.M., I.S., J.W.), Centre for Computational Systems Biology (R.N., I.S.), and Centre for Comparative Analysis of Biomolecular Networks (N.L.T., A.H.M.), University of Western Australia, Crawley 6009, Western Australia, Australia
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63
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Cardi T, Giegé P, Kahlau S, Scotti N. Expression Profiling of Organellar Genes. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2012. [DOI: 10.1007/978-94-007-2920-9_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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64
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Burch-Smith TM, Brunkard JO, Choi YG, Zambryski PC. Organelle-nucleus cross-talk regulates plant intercellular communication via plasmodesmata. Proc Natl Acad Sci U S A 2011; 108:E1451-60. [PMID: 22106293 PMCID: PMC3251100 DOI: 10.1073/pnas.1117226108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We use Arabidopsis thaliana embryogenesis as a model system for studying intercellular transport via plasmodesmata (PD). A forward genetic screen for altered PD transport identified increased size exclusion limit (ise) 1 and ise2 mutants with increased intercellular transport of fluorescent 10-kDa tracers. Both ise1 and ise2 exhibit increased formation of twinned and branched PD. ISE1 encodes a mitochondrial DEAD-box RNA helicase, whereas ISE2 encodes a DEVH-type RNA helicase. Here, we show that ISE2 foci are localized to the chloroplast stroma. Surprisingly, plastid development is defective in both ise1 and ise2 mutant embryos. In an effort to understand how RNA helicases that localize to different organelles have similar impacts on plastid and PD development/function, we performed whole-genome expression analyses. The most significantly affected class of transcripts in both mutants encode products that target to and enable plastid function. These results reinforce the importance of plastid-mitochondria-nucleus cross-talk, add PD as a critical player in the plant cell communication network, and thereby illuminate a previously undescribed signaling pathway dubbed organelle-nucleus-plasmodesmata signaling. Several genes with roles in cell wall synthesis and modification are also differentially expressed in both mutants, providing new targets for investigating PD development and function.
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Affiliation(s)
| | | | - Yoon Gi Choi
- Functional Genomics Laboratory, University of California, Berkeley, CA 94720
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65
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Liu L, Sanosaka M, Lei S, Bestwick ML, Frey JH, Surovtseva YV, Shadel GS, Cooper MP. LRP130 protein remodels mitochondria and stimulates fatty acid oxidation. J Biol Chem 2011; 286:41253-41264. [PMID: 21971050 PMCID: PMC3308838 DOI: 10.1074/jbc.m111.276121] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/21/2011] [Indexed: 11/06/2022] Open
Abstract
Impaired oxidative phosphorylation (OXPHOS) is implicated in several metabolic disorders. Even though mitochondrial DNA encodes several subunits critical for OXPHOS, the metabolic consequence of activating mitochondrial transcription remains unclear. We show here that LRP130, a protein involved in Leigh syndrome, increases hepatic β-fatty acid oxidation. Using convergent genetic and biochemical approaches, we demonstrate LRP130 complexes with the mitochondrial RNA polymerase to activate mitochondrial transcription. Activation of mitochondrial transcription is associated with increased OXPHOS activity, increased supercomplexes, and denser cristae, independent of mitochondrial biogenesis. Consistent with increased oxidative phosphorylation, ATP levels are increased in both cells and mouse liver, whereas coupled respiration is increased in cells. We propose activation of mitochondrial transcription remodels mitochondria and enhances oxidative metabolism.
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Affiliation(s)
- Lijun Liu
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Masato Sanosaka
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Shi Lei
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Megan L Bestwick
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Joseph H Frey
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Yulia V Surovtseva
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Gerald S Shadel
- Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Marcus P Cooper
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
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66
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Kühn K, Carrie C, Giraud E, Wang Y, Meyer EH, Narsai R, des Francs-Small CC, Zhang B, Murcha MW, Whelan J. The RCC1 family protein RUG3 is required for splicing of nad2 and complex I biogenesis in mitochondria of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:1067-80. [PMID: 21623974 DOI: 10.1111/j.1365-313x.2011.04658.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We have identified a mitochondrial protein (RUG3) that is required for accumulation of mitochondrial respiratory chain complex I. RUG3 is related to human REGULATOR OF CHROMOSOME CONDENSATION 1 (RCC1) and Arabidopsis UV-B RESISTANCE 8 (UVR8). Although the family of RCC1-like proteins in Arabidopsis has over 20 members, UVR8 is the sole plant representative of this family to have been functionally characterized. Mitochondria from Arabidopsis plants lacking a functional RUG3 gene showed greatly reduced complex I abundance and activity. In contrast, accumulation of complexes III, IV and V of the oxidative phosphorylation system and the capacity for succinate-dependent respiration were unaffected. A comprehensive study of processes contributing to complex I biogenesis in rug3 mutants revealed that RUG3 is required for efficient splicing of the nad2 mRNA, which encodes a complex I subunit. A comparison of the formation of complex I assembly intermediates between rug3 and wild type mitochondria indicated that NAD2 enters the assembly pathway at an early stage. Remarkably, rug3 mutants displayed increased capacities for import of nucleus-encoded mitochondrial proteins into the organelle and showed moderately increased mitochondrial transcript levels. This observation is consistent with global transcript changes indicating enhanced mitochondrial biogenesis in the rug3 mutant in response to the complex I defect.
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Affiliation(s)
- Kristina Kühn
- Australian Research Council Centre of Excellence in Plant Energy Biology, M316, University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
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67
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Leister D, Wang X, Haberer G, Mayer KF, Kleine T. Intracompartmental and intercompartmental transcriptional networks coordinate the expression of genes for organellar functions. PLANT PHYSIOLOGY 2011; 157:386-404. [PMID: 21775496 PMCID: PMC3165886 DOI: 10.1104/pp.111.177691] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Genes for mitochondrial and chloroplast proteins are distributed between the nuclear and organellar genomes. Organelle biogenesis and metabolism, therefore, require appropriate coordination of gene expression in the different compartments to ensure efficient synthesis of essential multiprotein complexes of mixed genetic origin. Whereas organelle-to-nucleus signaling influences nuclear gene expression at the transcriptional level, organellar gene expression (OGE) is thought to be primarily regulated posttranscriptionally. Here, we show that intracompartmental and intercompartmental transcriptional networks coordinate the expression of genes for organellar functions. Nearly 1,300 ATH1 microarray-based transcriptional profiles of nuclear and organellar genes for mitochondrial and chloroplast proteins in the model plant Arabidopsis (Arabidopsis thaliana) were analyzed. The activity of genes involved in organellar energy production (OEP) or OGE in each of the organelles and in the nucleus is highly coordinated. Intracompartmental networks that link the OEP and OGE gene sets serve to synchronize the expression of nucleus- and organelle-encoded proteins. At a higher regulatory level, coexpression of organellar and nuclear OEP/OGE genes typically modulates chloroplast functions but affects mitochondria only when chloroplast functions are perturbed. Under conditions that induce energy shortage, the intercompartmental coregulation of photosynthesis genes can even override intracompartmental networks. We conclude that dynamic intracompartmental and intercompartmental transcriptional networks for OEP and OGE genes adjust the activity of organelles in response to the cellular energy state and environmental stresses, and we identify candidate cis-elements involved in the transcriptional coregulation of nuclear genes. Regarding the transcriptional regulation of chloroplast genes, novel tentative target genes of σ factors are identified.
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68
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Liere K, Weihe A, Börner T. The transcription machineries of plant mitochondria and chloroplasts: Composition, function, and regulation. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1345-60. [PMID: 21316793 DOI: 10.1016/j.jplph.2011.01.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 01/07/2011] [Accepted: 01/10/2011] [Indexed: 05/04/2023]
Abstract
Although genomes of mitochondria and plastids are very small compared to those of their bacterial ancestors, the transcription machineries of these organelles are of surprising complexity. With respect to the number of different RNA polymerases per organelle, the extremes are represented on one hand by chloroplasts of eudicots which use one bacterial-type RNA polymerase and two phage-type RNA polymerases to transcribe their genes, and on the other hand by Physcomitrella possessing three mitochondrial RNA polymerases of the phage type. Transcription of genes/operons is often driven by multiple promoters in both organelles. This review describes the principle components of the transcription machineries (RNA polymerases, transcription factors, promoters) and the division of labor between the different RNA polymerases. While regulation of transcription in mitochondria seems to be only of limited importance, the plastid genes of higher plants respond to exogenous and endogenous cues rather individually by altering their transcriptional activities.
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Affiliation(s)
- Karsten Liere
- Institut für Biologie/Genetik, Humboldt-Universität zu Berlin, Chausseestrasse 117, Berlin, Germany
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69
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Xiang L, Le Roy K, Bolouri-Moghaddam MR, Vanhaecke M, Lammens W, Rolland F, Van den Ende W. Exploring the neutral invertase-oxidative stress defence connection in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:3849-62. [PMID: 21441406 PMCID: PMC3134342 DOI: 10.1093/jxb/err069] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Over the past decades, considerable advances have been made in understanding the crucial role and the regulation of sucrose metabolism in plants. Among the various sucrose-catabolizing enzymes, alkaline/neutral invertases (A/N-Invs) have long remained poorly studied. However, recent findings have demonstrated the presence of A/N-Invs in various organelles in addition to the cytosol, and their importance for plant development and stress tolerance. A cytosolic (At-A/N-InvG, At1g35580) and a mitochondrial (At-A/N-InvA, At1g56560) member of the A/N-Invs have been analysed in more detail in Arabidopsis and it was found that At-A/N-InvA knockout plants show an even more severe growth phenotype than At-A/N-InvG knockout plants. The absence of either A/N-Inv was associated with higher oxidative stress defence gene expression, while transient overexpression of At-A/N-InvA and At-A/N-InvG in leaf mesophyll protoplasts down-regulated the oxidative stress-responsive ascorbate peroxidase 2 (APX2) promoter. Moreover, up-regulation of the APX2 promoter by hydrogen peroxide or abscisic acid could be blocked by adding metabolizable sugars or ascorbate. A hypothetical model is proposed in which both mitochondrial and cytosolic A/N-Invs can generate glucose as a substrate for mitochondria-associated hexokinase, contributing to mitochondrial reactive oxygen species homeostasis.
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Affiliation(s)
- Li Xiang
- KULeuven, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Katrien Le Roy
- KULeuven, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Mohammad-Reza Bolouri-Moghaddam
- Department of Agronomy, Plant Breeding and Biotechnology, Faculty of Crop Science, Sari Agricultural Science and Natural Resources University, Sari, Iran
| | - Mieke Vanhaecke
- KULeuven, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Willem Lammens
- KULeuven, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Filip Rolland
- KULeuven, Laboratory of Functional Biology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Wim Van den Ende
- KULeuven, Laboratory of Molecular Plant Physiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
- To whom correspondence should be addressed. E-mail:
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70
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Wang J, Wang Y, Wang Z, Liu L, Zhu XG, Ma X. Synchronization of cytoplasmic and transferred mitochondrial ribosomal protein gene expression in land plants is linked to Telo-box motif enrichment. BMC Evol Biol 2011; 11:161. [PMID: 21668973 PMCID: PMC3212954 DOI: 10.1186/1471-2148-11-161] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 06/13/2011] [Indexed: 02/08/2023] Open
Abstract
Background Chloroplasts and mitochondria evolved from the endosymbionts of once free-living eubacteria, and they transferred most of their genes to the host nuclear genome during evolution. The mechanisms used by plants to coordinate the expression of such transferred genes, as well as other genes in the host nuclear genome, are still poorly understood. Results In this paper, we use nuclear-encoded chloroplast (cpRPGs), as well as mitochondrial (mtRPGs) and cytoplasmic (euRPGs) ribosomal protein genes to study the coordination of gene expression between organelles and the host. Results show that the mtRPGs, but not the cpRPGs, exhibit strongly synchronized expression with euRPGs in all investigated land plants and that this phenomenon is linked to the presence of a telo-box DNA motif in the promoter regions of mtRPGs and euRPGs. This motif is also enriched in the promoter regions of genes involved in DNA replication. Sequence analysis further indicates that mtRPGs, in contrast to cpRPGs, acquired telo-box from the host nuclear genome. Conclusions Based on our results, we propose a model of plant nuclear genome evolution where coordination of activities in mitochondria and chloroplast and other cellular functions, including cell cycle, might have served as a strong selection pressure for the differential acquisition of telo-box between mtRPGs and cpRPGs. This research also highlights the significance of physiological needs in shaping transcriptional regulatory evolution.
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Affiliation(s)
- Jie Wang
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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71
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Yoshida K, Watanabe CK, Hachiya T, Tholen D, Shibata M, Terashima I, Noguchi K. Distinct responses of the mitochondrial respiratory chain to long- and short-term high-light environments in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2011; 34:618-28. [PMID: 21251020 DOI: 10.1111/j.1365-3040.2010.02267.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In order to ensure the cooperative function with the photosynthetic system, the mitochondrial respiratory chain needs to flexibly acclimate to a fluctuating light environment. The non-phosphorylating alternative oxidase (AOX) is a notable respiratory component that may support a cellular redox homeostasis under high-light (HL) conditions. Here we report the distinct acclimatory manner of the respiratory chain to long- and short-term HL conditions and the crucial function of AOX in Arabidopsis thaliana leaves. Plants grown under HL conditions (HL plants) possessed a larger ubiquinone (UQ) pool and a higher amount of cytochrome c oxidase than plants grown under low light conditions (LL plants). These responses in HL plants may be functional for efficient ATP production and sustain the fast plant growth. When LL plants were exposed to short-term HL stress (sHL), the UQ reduction level was transiently elevated. In the wild-type plant, the UQ pool was re-oxidized concomitantly with an up-regulation of AOX. On the other hand, the UQ reduction level of the AOX-deficient aox1a mutant remained high. Furthermore, the plastoquinone pool was also more reduced in the aox1a mutant under such conditions. These results suggest that AOX plays an important role in rapid acclimation of the respiratory chain to sHL, which may support efficient photosynthetic performance.
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Affiliation(s)
- Keisuke Yoshida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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72
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Hammani K, Gobert A, Hleibieh K, Choulier L, Small I, Giegé P. An Arabidopsis dual-localized pentatricopeptide repeat protein interacts with nuclear proteins involved in gene expression regulation. THE PLANT CELL 2011; 23:730-40. [PMID: 21297037 PMCID: PMC3077779 DOI: 10.1105/tpc.110.081638] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Following the endosymbiotic acquisition of mitochondria by eukaryotic cells, most of the genes in this organelle were transferred to the nucleus. To maintain mitochondrial biogenesis and function, nuclear and mitochondrial genomes require regulated and coordinated expression. In plant organelles, nuclear-encoded proteins targeted to the organelles control posttranscriptional and posttranslational mechanisms. Pentatricopeptide repeat (PPR) proteins are good candidates to play such regulatory roles. Here, we identify PNM1 (for PPR protein localized to the nucleus and mitochondria 1), a novel PPR protein that is dual localized to mitochondria and nuclei in Arabidopsis thaliana, as observed by green fluorescent protein fusions and immunodetection on subcellular fractions and on histological sections. Genetic complementation showed that loss of PNM1 function in mitochondria, but not in nuclei, is lethal for the embryo. In mitochondria, it is associated with polysomes and may play a role in translation. A genetic screen in yeast identified protein partners of PNM1. These partners, the nucleosome assembly protein NAP1, and the transcription factor TCP8 interact with PNM1 in the nucleus in planta. Furthermore, TCP8 can bind the promoter of PNM1. This suggests that PNM1 might be involved in the regulation of its own gene expression in the nucleus and could thus play a role in gene expression adjustments between mitochondria and the nucleus.
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Affiliation(s)
- Kamel Hammani
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg Cedex, France
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Anthony Gobert
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg Cedex, France
| | - Kamal Hleibieh
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg Cedex, France
| | - Laurence Choulier
- Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg, Centre National de la Recherche Scientifique/Université de Strasbourg, 67400 Illkirch Cedex, France
| | - Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg Cedex, France
- Address correspondence to
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73
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Leister D, Kleine T. Role of intercompartmental DNA transfer in producing genetic diversity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 291:73-114. [PMID: 22017974 DOI: 10.1016/b978-0-12-386035-4.00003-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In eukaryotic cells, genes are found in three compartments-the nucleus, mitochondria, and plastids-and extensive gene transfer has occurred between them. Most organellar genes in the nucleus migrated there long ago, but transfer is ongoing and ubiquitous. It now generates mostly noncoding nuclear DNA, can also disrupt gene functions, and reshape genes by adding novel exons. Plastid or nuclear sequences have also contributed to the formation of mitochondrial tRNA genes. It is now clear that organelle-to-nucleus DNA transfer involves the escape of DNA molecules from the organelles at times of stress or at certain developmental stages, and their subsequent incorporation at sites of double-stranded breaks in nuclear DNA by nonhomologous recombination. Intercompartmental DNA transfer thus appears to be an inescapable phenomenon that has had a broad impact on eukaryotic evolution, affecting DNA repair, gene and genome evolution, and redirecting proteins to different target compartments.
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Affiliation(s)
- Dario Leister
- Lehrstuhl für Molekularbiologie der Pflanzen, Department Biologie I, Ludwig-Maximilians-Universität München-LMU, Planegg-Martinsried, Germany
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74
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Busi MV, Gomez-Lobato ME, Rius SP, Turowski VR, Casati P, Zabaleta EJ, Gomez-Casati DF, Araya A. Effect of mitochondrial dysfunction on carbon metabolism and gene expression in flower tissues of Arabidopsis thaliana. MOLECULAR PLANT 2011; 4:127-43. [PMID: 20978083 DOI: 10.1093/mp/ssq065] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We characterized the transcriptomic response of transgenic plants carrying a mitochondrial dysfunction induced by the expression of the unedited form of the ATP synthase subunit 9. The u-ATP9 transgene driven by A9 and APETALA3 promoters induce mitochondrial dysfunction revealed by a decrease in both oxygen uptake and adenine nucleotides (ATP, ADP) levels without changes in the ATP/ADP ratio. Furthermore, we measured an increase in ROS accumulation and a decrease in glutathione and ascorbate levels with a concomitant oxidative stress response. The transcriptome analysis of young Arabidopsis flowers, validated by qRT-PCR and enzymatic or functional tests, showed dramatic changes in u-ATP9 plants. Both lines display a modification in the expression of various genes involved in carbon, lipid, and cell wall metabolism, suggesting that an important metabolic readjustment occurs in plants with a mitochondrial dysfunction. Interestingly, transcript levels involved in mitochondrial respiration, protein synthesis, and degradation are affected. Moreover, the levels of several mRNAs encoding for transcription factors and DNA binding proteins were also changed. Some of them are involved in stress and hormone responses, suggesting that several signaling pathways overlap. Indeed, the transcriptome data revealed that the mitochondrial dysfunction dramatically alters the expression of genes involved in signaling pathways, including those related to ethylene, absicic acid, and auxin signal transduction. Our data suggest that the mitochondrial dysfunction model used in this report may be useful to uncover the retrograde signaling mechanism between the nucleus and mitochondria in plant cells.
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Affiliation(s)
- Maria V Busi
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH) CONICET/UNSAM, Chascomús, Argentina
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75
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Millar AH, Whelan J, Soole KL, Day DA. Organization and regulation of mitochondrial respiration in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2011; 62:79-104. [PMID: 21332361 DOI: 10.1146/annurev-arplant-042110-103857] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mitochondrial respiration in plants provides energy for biosynthesis, and its balance with photosynthesis determines the rate of plant biomass accumulation. We describe recent advances in our understanding of the mitochondrial respiratory machinery of cells, including the presence of a classical oxidative phosphorylation system linked to the cytosol by transporters, discussed alongside nonphosphorylating (and, therefore, non-energy conserving) bypasses that alter the efficiency of ATP synthesis and play a role in oxidative stress responses in plants. We consider respiratory regulation in the context of the contrasting roles mitochondria play in different tissues, from photosynthetic leaves to nutrient-acquiring roots. We focus on the molecular nature of this regulation at transcriptional and post-transcriptional levels that allow the respiratory apparatus of plants to help shape organ development and the response of plants to environmental stress. We highlight the challenges for future research considering spatial and temporal changes of respiration in response to changing climatic conditions.
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Affiliation(s)
- A Harvey Millar
- Australian Research Council Center of Excellence in Plant Energy Biology, University of Western Australia, M316 Crawley, Western Australia 6009, Australia
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76
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Preuten T, Cincu E, Fuchs J, Zoschke R, Liere K, Börner T. Fewer genes than organelles: extremely low and variable gene copy numbers in mitochondria of somatic plant cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:948-59. [PMID: 21143676 DOI: 10.1111/j.1365-313x.2010.04389.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plant mitochondrial genomes are split into sub-genomes, i.e. genes are distributed across various sub-genomic molecules. To investigate whether copy numbers vary between individual mitochondrial genes, we used quantitative real-time PCR in combination with flow cytometric determination of nuclear DNA quantities to determine absolute per-cell-copy numbers of four mitochondrial genes in various Arabidopsis organs and the leaves of tobacco (Nicotiana tabacum) and barley (Hordeum vulgare). The copy numbers of the investigated mitochondrial genes (atp1, rps4, nad6 and cox1) not only differed from each other, but also varied between organs and changed during the development of cotyledons and leaves in Arabidopsis. We found no correlation between altered gene copy numbers, transcript levels and O(2) consumption. However, per cell, both the number of mitochondria and the number of gene copies increased with growing cell size. Gene copy numbers varied from approximately 40 (cox1 in young leaves) to approximately 280 (atp1 in mature leaves), and the mean number of mitochondria was approximately 300 in young leaves and 450 in mature leaves. Thus, cells are polyploid with respect to their mitochondrial genomes, but individual mitochondria may contain only part of the genome or even no DNA at all. Our data supports structural models of the mitochondrial genome in non-dividing cells of angiosperms that predict localization of the genes on sub-genomic molecules rather than master chromosomes. The data indicate control of the number of individual genes according to the genotype and developmental program(s) via amplification and/or degradation of sub-genomic molecules.
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Affiliation(s)
- Tobias Preuten
- Institut für Biologie, Humboldt-Universität, Chausseestraße 117, D-10115 Berlin, Germany
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77
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Sung TY, Tseng CC, Hsieh MH. The SLO1 PPR protein is required for RNA editing at multiple sites with similar upstream sequences in Arabidopsis mitochondria. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:499-511. [PMID: 20497377 DOI: 10.1111/j.1365-313x.2010.04258.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In Arabidopsis, RNA editing changes more than 500 cytidines to uridines in mitochondrial transcripts. The editing enzyme and co-factors involved in these processes are largely unknown. We have identified a nuclear gene SLOW GROWTH1 (SLO1) encoding an E motif-containing pentatricopeptide repeat protein that is required for RNA editing of nad4 and nad9 in Arabidopsis mitochondria. The SLO1 protein is localized to the mitochondrion, and its absence gives rise to small plants with slow growth and delayed development. A survey of approximately 500 mitochondrial RNA editing sites in Arabidopsis reveals that the editing of two sites, nad4-449 and nad9-328, is abolished in the slo1 mutants. Sequence comparison in the upstream (from -1 to -15 bp) of nad4-449 and nad9-328 editing sites shows that nine of the 15 nucleotides are identical. In addition to RNA editing, we used RNA gel blot analysis to compare the abundance and banding patterns of mitochondrial transcripts between the wild type and slo1 mutants. Of the 79 genes and open reading frames examined, steady-state levels of 56 mitochondrial transcripts are increased in the slo1 mutants. These results suggest that the SLO1 protein may indirectly regulate plant growth and development via affecting mitochondrial RNA editing and gene expression.
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Affiliation(s)
- Tzu-Ying Sung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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78
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Pfannschmidt T. Plastidial retrograde signalling--a true "plastid factor" or just metabolite signatures? TRENDS IN PLANT SCIENCE 2010; 15:427-35. [PMID: 20580596 DOI: 10.1016/j.tplants.2010.05.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 05/17/2010] [Accepted: 05/17/2010] [Indexed: 05/03/2023]
Abstract
The genetic compartments of plant cells, nuclei, plastids and mitochondria exchange information by anterograde (nucleus-to-organelle) and retrograde (organelle-to-nucleus) signalling. These avenues of communication coordinate activities during the organelles' development and function. Despite extensive research retrograde signalling remains poorly understood. The proposed cytosolic signalling pathways and the putative organellar signalling molecules remain elusive, and a clear functional distinction from the signalling cascades of other cellular perception systems (i.e. photoreceptors or phytohormones) is difficult to obtain. Notwithstanding the stagnant progress, some basic assumptions about the process have remained virtually unchanged for many years, potentially obstructing the view on alternative routes for retrograde communication. Here, I critically assess the current models of retrograde signalling and discuss novel ideas and potential connections.
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Affiliation(s)
- Thomas Pfannschmidt
- Institute of General Botany and Plant Physiology, Department of Plant Physiology, University of Jena, Dornburger Str. 159, 07743 Jena, Germany.
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79
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Naydenov NG, Khanam S, Siniauskaya M, Nakamura C. Profiling of mitochondrial transcriptome in germinating wheat embryos and seedlings subjected to cold, salinity and osmotic stresses. Genes Genet Syst 2010; 85:31-42. [DOI: 10.1266/ggs.85.31] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Nayden G. Naydenov
- Laboratory of Plant Genetics, Department of Agroenvironmental Science, Graduate School of Agricultural Science, Kobe University
| | - Sakina Khanam
- Laboratory of Plant Genetics, Department of Agroenvironmental Science, Graduate School of Agricultural Science, Kobe University
| | - Maryna Siniauskaya
- Laboratory of Plant Genetics, Department of Agroenvironmental Science, Graduate School of Agricultural Science, Kobe University
| | - Chiharu Nakamura
- Laboratory of Plant Genetics, Department of Agroenvironmental Science, Graduate School of Agricultural Science, Kobe University
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80
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Comelli RN, Gonzalez DH. Divergent regulatory mechanisms in the response of respiratory chain component genes to carbohydrates suggests a model for gene evolution after duplication. PLANT SIGNALING & BEHAVIOR 2009; 4:1179-81. [PMID: 20514241 PMCID: PMC2819451 DOI: 10.4161/psb.4.12.10045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 09/10/2009] [Accepted: 09/10/2009] [Indexed: 05/10/2023]
Abstract
The biogenesis of the plant mitochondrial respiratory chain needs the coordinated synthesis and assembly of the products of more than 100 genes located in the nucleus and within the organelle. One of the factors that regulate the expression of nuclear genes is the availability of carbohydrates. This regulation operates at the transcriptional level through elements present in the promoter regions of respiratory chain component genes. Recent studies of the promoters of two Arabidopsis genes that encode subunit 5b of cytochrome c oxidase suggest that these genes use different molecular mechanisms to respond to carbohydrates. A model is postulated in which one of the genes retained ancient expression characteristics while the other one incorporated novel response elements that allowed a progressive divergence of regulatory mechanisms.
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Affiliation(s)
- Raúl N Comelli
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
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81
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Van Aken O, Zhang B, Carrie C, Uggalla V, Paynter E, Giraud E, Whelan J. Defining the mitochondrial stress response in Arabidopsis thaliana. MOLECULAR PLANT 2009; 2:1310-24. [PMID: 19995732 DOI: 10.1093/mp/ssp053] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
To obtain a global overview of how mitochondria respond to stress, we aimed to define the plant mitochondrial stress response (MSR). By combining a set of 1196 Arabidopsis thaliana genes that putatively encode mitochondrial proteins with 16 microarray experiments on stress-related conditions, 45 nuclear encoded genes were defined as widely stress-responsive. Using green fluorescent protein (GFP) fusion assays, the mitochondrial targeting of a large number of these proteins was tested, confirming in total 26 proteins as mitochondrially targeted. Several of these proteins were observed to be dual targeted to mitochondria and plastids, including the small heat shock proteins sHSP23.5 and sHSP23.6. In addition to the well defined stress components of mitochondria, such as alternative oxidases, nicotinamide adenine dinucleotide (NAD(P)H) dehydrogenases, and heat shock proteins, a variety of other proteins, many with unknown function, were identified. The mitochondrial carrier protein family was over-represented in the stress-responsive genes, suggesting that stress induces altered needs for metabolite transport across the mitochondrial inner membrane. Although the genes encoding many of these proteins contain common cis-acting regulatory elements, it was apparent that a number of distinct regulatory processes or signals likely triggered the MSR. Therefore, these genes provide new model systems to study mitochondrial retrograde regulation, in addition to the widely used alternative oxidase model. Additionally, as changes in proteins responsive to stress did not correlate well with changes at a transcript level, it suggests that post-transcriptional mechanisms also play an important role in defining the MSR.
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Affiliation(s)
- Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, MCS Building M316, University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia
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82
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Comelli RN, Gonzalez DH. Identification of regulatory elements involved in expression and induction by sucrose and UV-B light of the Arabidopsis thaliana COX5b-2 gene, encoding an isoform of cytochrome c oxidase subunit 5b. PHYSIOLOGIA PLANTARUM 2009; 137:213-224. [PMID: 19781003 DOI: 10.1111/j.1399-3054.2009.01285.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The promoter sequences required for expression of the Arabidopsis thaliana COX5b-2 gene, encoding an isoform of cytochrome c oxidase subunit 5b, were analyzed using plants transformed with deleted and mutagenized forms of the promoter fused to gus. A 1000-bp promoter fragment produces expression in root and shoot meristems, leaf and cotyledon tips, and anthers. Deletion analysis indicated the presence of positive and negative regulatory elements. A regulatory element located between -660 and -620 from the translation start site was identified as a G-box by mutagenic analysis. Mutation of the G-box, that is present within the coding region of the preceding gene in the genome, increases expression of COX5b-2 in cotyledon and leaf lamina and abolishes induction by ultraviolet-B (UV-B) light, which presumably acts through the removal of an inhibitory factor. Identified positive regulatory elements include a site II element (TGGGCC), a related element with the sequence TGGGTC and four initiator elements (YTCANTYY) that completely abolish expression when mutated in combination. Site II elements are also involved in the response to sucrose. The results imply that the COX5b-2 gene has retained expression characteristics presented by most respiratory chain component genes, but its expression mechanisms have diverged from those employed by COX5b-1, the other gene encoding cytochrome c oxidase subunit 5b in Arabidopsis.
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Affiliation(s)
- Raúl N Comelli
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, Santa Fe, Argentina
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83
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Hinrichsen I, Bolle N, Paun L, Kempken F. RNA processing in plant mitochondria is independent of transcription. PLANT MOLECULAR BIOLOGY 2009; 70:663-668. [PMID: 19412686 DOI: 10.1007/s11103-009-9498-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 04/18/2009] [Indexed: 05/27/2023]
Abstract
We analyzed the ability of plant mitochondria to process introduced RNA. Arabidopsis thaliana cox2 transcripts were synthesized in vitro. The in vitro transcribed mRNA was electroporated into maize and cauliflower mitochondria and incubated in organello. RNA was isolated and RT-PCR was carried out to analyze RNA processing. Our data indicate that cox2 transcripts introduced into isolated plant mitochondria are processed completely. This is the first report of in organello editing of introduced transcripts. We also found that none of the transcription, translation, or respiration inhibitors we used influenced RNA splicing or RNA editing of the cox2 transcript. Thus, our data also demonstrate that plant mitochondrial RNA processing may be independent of both transcription and respiratory regulation.
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Affiliation(s)
- Inga Hinrichsen
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
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84
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Mufarrege EF, Curi GC, Gonzalez DH. Common sets of promoter elements determine the expression characteristics of three Arabidopsis genes encoding isoforms of mitochondrial cytochrome c oxidase subunit 6b. PLANT & CELL PHYSIOLOGY 2009; 50:1393-1399. [PMID: 19493962 DOI: 10.1093/pcp/pcp080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The promoters of the three Arabidopsis nuclear genes encoding mitochondrial cytochrome c oxidase subunit 6b (AtCOX6b) have similar expression patterns, with preferential expression in anthers and meristems, and are induced by sucrose and etiolation. Additionally, induction of AtCOX6b-1 by GA(3) and AtCOX6b-3 by 6-benzylaminopurine was observed. Site II elements (TGGGCC/T) present in the three promoters bind common nuclear proteins and are important for basal and induced expression. Induction by sucrose requires, in addition, the integrity of elements with the sequence TACTAA. The results imply the participation of common regulatory factors in the expression of the three Arabidopsis COX6b genes.
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Affiliation(s)
- Eduardo F Mufarrege
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
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85
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Comelli RN, Viola IL, Gonzalez DH. Characterization of promoter elements required for expression and induction by sucrose of the Arabidopsis COX5b-1 nuclear gene, encoding the zinc-binding subunit of cytochrome c oxidase. PLANT MOLECULAR BIOLOGY 2009; 69:729-743. [PMID: 19125337 DOI: 10.1007/s11103-008-9451-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 12/17/2008] [Indexed: 05/27/2023]
Abstract
Arabidopsis COX5b-1 encodes an isoform of the zinc binding subunit 5b of mitochondrial cytochrome c oxidase. A promoter region required for expression and induction by sucrose of this gene was analyzed using plants stably transformed with mutagenized promoter fragments fused to the gus reporter gene. Promoter dependent expression is absolutely dependent on a G-box present at -228 from the translation start site. This element interacts in vitro and in vivo with transcription factors from the bZip family, preferentially with the abscisic acid-responsive element binding factor AREB2/ABF4. A region located upstream of the G-box (-333/-259) contains elements with the core sequence ATCATT and distalB-like sequences (CCACTTG) that are required for expression in vegetative tissues. These sequences bind different sets of proteins present in plant nuclear extracts and participate in induction by sucrose (ATCATT) and abscisic acid (distalB) of the COX5b-1 promoter. We propose that the COX5b-1 promoter has acquired novel regulatory mechanisms during evolution after gene duplication. These novel mechanisms have allowed the diversification of expression patterns, but also the conservation of some responses that, as induction by sucrose, are shared by COX5b-1 and other genes encoding components of the mitochondrial respiratory chain. Conservation of these responses may be a pre-requisite for the successful incorporation of new regulatory elements in this class of genes.
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Affiliation(s)
- Raúl N Comelli
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina
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86
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Skinner DJ, Gasser CS. Expression-based discovery of candidate ovule development regulators through transcriptional profiling of ovule mutants. BMC PLANT BIOLOGY 2009; 9:29. [PMID: 19291320 PMCID: PMC2664812 DOI: 10.1186/1471-2229-9-29] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 03/16/2009] [Indexed: 05/05/2023]
Abstract
BACKGROUND Arabidopsis ovules comprise four morphologically distinct parts: the nucellus, which contains the embryo sac, two integuments that become the seed coat, and the funiculus that anchors the ovule within the carpel. Analysis of developmental mutants has shown that ovule morphogenesis relies on tightly regulated genetic interactions that can serve as a model for developmental regulation. Redundancy, pleiotropic effects and subtle phenotypes may preclude identification of mutants affecting some processes in screens for phenotypic changes. Expression-based gene discovery can be used access such obscured genes. RESULTS Affymetrix microarrays were used for expression-based gene discovery to identify sets of genes expressed in either or both integuments. The genes were identified by comparison of pistil mRNA from wild type with mRNA from two mutants; inner no outer (ino, which lacks the outer integument), and aintegumenta (ant, which lacks both integuments). Pools of pistils representing early and late stages of ovule development were evaluated and data from the three genotypes were used to designate genes that were predominantly expressed in the integuments using pair-wise and cluster analyses. Approximately two hundred genes were found to have a high probability of preferential expression in these structures, and the predictive nature of the expression classes was confirmed with reverse transcriptase polymerase chain reaction and in situ hybridization. CONCLUSION The results showed that it was possible to use a mutant, ant, with broad effects on plant phenotype to identify genes expressed specifically in ovules, when coupled with predictions from known gene expression patterns, or in combination with a more specific mutant, ino. Robust microarray averaging (RMA) analysis of array data provided the most reliable comparisons, especially for weakly expressed genes. The studies yielded an over-abundance of transcriptional regulators in the identified genes, and these form a set of candidate genes for evaluation of roles in ovule development using reverse genetics.
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Affiliation(s)
- Debra J Skinner
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
- Department of Crop Science, University of Illinois, Urbana, IL 61801, USA
| | - Charles S Gasser
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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87
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Rigas S, Daras G, Laxa M, Marathias N, Fasseas C, Sweetlove LJ, Hatzopoulos P. Role of Lon1 protease in post-germinative growth and maintenance of mitochondrial function in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2009; 181:588-600. [PMID: 19076295 DOI: 10.1111/j.1469-8137.2008.02701.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Maintenance of protein quality control and turnover is essential for cellular homeostasis. In plant organelles this biological process is predominantly performed by ATP-dependent proteases. Here, a genetic screen was performed that led to the identification of Arabidopsis thaliana Lon1 protease mutants that exhibit a post-embryonic growth retardation phenotype. Translational fusion to yellow fluorescent protein revealed AtLon1 subcellular localization in plant mitochondria, and the AtLon1 gene could complement the respiratory-deficient phenotype of the yeast PIM1 gene homolog. AtLon1 is highly expressed in rapidly growing plant organs of embryonic origin, including cotyledons and primary roots, and in inflorescences, which have increased mitochondria numbers per cell to fulfill their high energy requirements. In lon1 mutants, the expression of both mitochondrial and nuclear genes encoding respiratory proteins was normal. However, mitochondria isolated from lon1 mutants had a lower capacity for respiration of succinate and cytochrome c via complexes II and IV, respectively. Furthermore, the activity of key enzymes of the tricarboxylic acid (TCA) cycle was significantly reduced. Additionally, mitochondria in lon1 mutants had an aberrant morphology. These results shed light on the developmental mechanisms of selective proteolysis in plant mitochondria and suggest a critical role for AtLon1 protease in organelle biogenesis and seedling establishment.
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Affiliation(s)
- Stamatis Rigas
- Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, Athens 118 55, Greece
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88
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Welchen E, Viola IL, Kim HJ, Prendes LP, Comelli RN, Hong JC, Gonzalez DH. A segment containing a G-box and an ACGT motif confers differential expression characteristics and responses to the Arabidopsis Cytc-2 gene, encoding an isoform of cytochrome c. JOURNAL OF EXPERIMENTAL BOTANY 2008; 60:829-845. [PMID: 19098132 DOI: 10.1093/jxb/ern331] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sequences required for the expression of Cytc-2 (At4g10040), one of two cytochrome c genes from Arabidopsis thaliana, were characterized using plants transformed with deleted and mutagenized promoter fragments fused to gus. These studies indicated that a region containing a G-box and an ACGT motif is essential for expression. Mutation of the ACGT motif causes a complete loss of expression, while mutation of the G-box causes decreased expression in aerial parts and abolishes expression in roots and induction by environmental factors. Upstream located site II elements are required for maximal expression, mainly in reproductive tissues, and maximal induction by different factors. One-hybrid screenings allowed the identification of transcription factors from the bZIP and bHLH families that interact mainly with the G-box. Four of these factors were able to bind to the Cytc-2 promoter in vitro and in transactivation assays in Arabidopsis. Analysis of available microarray data indicated that the bZIP transcription factors share expression characteristics with the Cytc-2 gene, suggesting that they act as mediators of its response to tissue-specific, environmental, and metabolic conditions. Site II elements interact with a TCP family protein and may co-ordinate the expression of the Cytc-2 gene with that of other respiratory chain components. A model is proposed for the evolution of the Cytc-2 gene through the incorporation of a segment containing a G-box and an ACGT motif into an ancestral gene that contained site II elements. This may have reduced the importance of site II elements for basal expression and conferred new responses to environmental factors.
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Affiliation(s)
- Elina Welchen
- Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina
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89
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Developmentally-specific transcripts from the ccmFN-rps1 locus in wheat mitochondria. Mol Genet Genomics 2008; 280:419-26. [PMID: 18766379 DOI: 10.1007/s00438-008-0375-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 08/19/2008] [Indexed: 10/21/2022]
Abstract
We have examined precursor and processed transcripts arising from the wheat mitochondrial ccmFN-rps1 region, which encodes a cytochrome c biogenesis component and S1 ribosomal protein, for the embryo-to-seedling stages of development. Northern analysis revealed 3.2-kb ccmFN-rps1 precursors, 2.6-kb bicistronic mRNA and 0.7-kb monocistronic rps1 transcripts, although their relative abundances were seen to shift during development. The 3.2-kb transcript levels peak during the 12-h to 2-day period, whereas 2.6-kb transcripts continue to increase during seedling growth, consistent with the newly-synthesized RNAs being more efficiently processed in later developmental stages. The 3.2-kb ccmFN-rps1 precursors consist of primary transcripts and 5'-processed RNAs based on pyrophosphatase-treated circular-RT-PCR analysis, whereas the 5' termini of 2.6-kb transcripts appear to be generated by endonucleolytic cleavage. The 0.7-kb rps1 transcripts are abundant during early germination but not in the seedlings; their 5' ends are heterogeneous and most of them lack the expected initiation codon. Notably all three size classes of RNAs share similar 3' termini. The 2.6-kb ccmFN-rps1 mRNAs exhibited full C-to-U editing at the sites examined, whereas the other two categories were slightly under-edited. A subset of all three-sized transcripts possessed short stretches of non-encoded adenosines, thus adding another layer of complexity to RNA level events in plant mitochondria.
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90
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Rayapuram N, Hagenmuller J, Grienenberger JM, Bonnard G, Giegé P. The three mitochondrial encoded CcmF proteins form a complex that interacts with CCMH and c-type apocytochromes in Arabidopsis. J Biol Chem 2008; 283:25200-25208. [PMID: 18644794 DOI: 10.1074/jbc.m802621200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three reading frames called ccmF(N1), ccmF(N2), and ccmF(c) are found in the mitochondrial genome of Arabidopsis. These sequences are similar to regions of the bacterial gene ccmF involved in cytochrome c maturation. ccmF genes are always absent from animal and fungi genomes but are found in mitochondrial genomes of land plant and several evolutionary distant eukaryotes. In Arabidopsis, ccmF(N2) despite the absence of a classical initiation codon is not a pseudo gene. The 3 ccmF genes of Arabidopsis are expressed at the protein level. Their products are integral proteins of the mitochondrial inner membrane with in total 11 to 13 predicted transmembrane helices. The conserved WWD domain of CcmF(N2) is localized in the inter membrane space. The 3 CcmF proteins are all detected in a high molecular mass complex of 500 kDa by Blue Native PAGE. Direct interaction between CcmF(N2) and both CcmF(N1) and CcmF(C) is shown with the yeast two-hybrid split ubiquitin system, but no interaction is observed between CcmF(N1) and CcmF(C). Similarly, interaction is detected between CcmF(N2) and apocytochrome c but also with apocytochrome c(1). Finally, CcmF(N1) and CcmF(N2) both interact with CCMH previously shown to interact as well with cytochrome c. This strengthens the hypothesis that CcmF and CCMH make a complex that performs the assembly of heme with c-type apocytochromes in plant mitochondria.
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Affiliation(s)
- Naganand Rayapuram
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 rue du général Zimmer, 67084 Strasbourg, France
| | - Jérémie Hagenmuller
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 rue du général Zimmer, 67084 Strasbourg, France
| | - Jean Michel Grienenberger
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 rue du général Zimmer, 67084 Strasbourg, France
| | - Géraldine Bonnard
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 rue du général Zimmer, 67084 Strasbourg, France
| | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes du CNRS, 12 rue du général Zimmer, 67084 Strasbourg, France.
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91
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Lee CP, Eubel H, O'Toole N, Millar AH. Heterogeneity of the Mitochondrial Proteome for Photosynthetic and Non-photosynthetic Arabidopsis Metabolism. Mol Cell Proteomics 2008; 7:1297-316. [DOI: 10.1074/mcp.m700535-mcp200] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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92
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Abstract
Following the acquisition of chloroplasts and mitochondria by eukaryotic cells during endosymbiotic evolution, most of the genes in these organelles were either lost or transferred to the nucleus. Encoding organelle-destined proteins in the nucleus allows for host control of the organelle. In return, organelles send signals to the nucleus to coordinate nuclear and organellar activities. In photosynthetic eukaryotes, additional interactions exist between mitochondria and chloroplasts. Here we review recent advances in elucidating the intracellular signalling pathways that coordinate gene expression between organelles and the nucleus, with a focus on photosynthetic plants.
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93
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Hammargren J, Rosenquist S, Jansson C, Knorpp C. A novel connection between nucleotide and carbohydrate metabolism in mitochondria: sugar regulation of the Arabidopsis nucleoside diphosphate kinase 3a gene. PLANT CELL REPORTS 2008; 27:529-534. [PMID: 18057937 DOI: 10.1007/s00299-007-0486-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/07/2007] [Accepted: 11/17/2007] [Indexed: 05/25/2023]
Abstract
Sugar metabolism is intricately connected with mitochondria through the conversion of sugars to ATP, and through the production of carbon skeletons that can be used in anabolic processes. Sugar molecules also take part in signalling cascades. In this study we investigated the impact of sucrose on the expression of the Arabidopsis thaliana Nucleoside Diphosphate Kinase gene family (NDPK, EC 2.7.4.6), focusing on NDPK3a, the product of which is located predominantly in mitochondria. Using quantitative PCR we show that the NDPK3a gene is subject to sucrose and glucose induction, while no other Arabidopsis NDPK gene are sucrose-inducible. The induction reaches a half-maximum after about 6 hours and is stable for at least 48 h. Sucrose and glucose inductions were found not to be affected by the presence of a hexokinase inhibitor, N-acetyl-glucosamine. Furthermore, turanose, a sucrose analogue that is not metabolised in plant cells, did not induce NDPK3a gene expression. An analysis of the NDPK3a gene revealed two WBOXHWISO1 boxes in the promoter region, elements that have previously been reported to be involved in sugar signalling in barley via the SUSIBA2 protein. SUSIBA2 belongs to the WRKY group of transcription factors. In this study we used two mutants containing T-DNA insertions in WRKY-genes, AtWrky4 and AtWrky34, to investigate the possible involvement of WRKY transcription factors in the sugar induction of NDPK3a.
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Affiliation(s)
- Jenni Hammargren
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
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94
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Khanam SM, Naydenov NG, Kadowaki KI, Nakamura C. Mitochondrial biogenesis as revealed by mitochondrial transcript profiles during germination and early seedling growth in wheat. Genes Genet Syst 2008; 82:409-20. [PMID: 17991996 DOI: 10.1266/ggs.82.409] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Germination of imbibed embryos is the initial stage of plant development that is accompanied by the burst of mitochondrial respiration. To understand the process of mitochondrial biogenesis during this critical stage in wheat development, we monitored changes in mitochondrial transcript profiles during the first 3 days by adopting a newly devised macroarray system. The whole experiment was conducted in the dark to avoid influences of photosynthesis. Dry quiescent embryos started respiration rapidly after imbibition and the rate of oxygen uptake increased to peak at the first day followed by a continuous decrease until the third day under this condition. Both the cytochrome and alternative electron transport pathways appeared to contribute to this initial burst. Shoot and root growth was also remarkable during this period. Mitochondrial transcriptome was studied by macroarray analysis using 28 mitochondrial protein-coding genes, 4 nuclear encoded mitochondria-targeted genes and 2 nuclear genes as control. All transcripts were present in dry embryos at different initial levels, and a large variability was observed in their abundance among individual genes throughout the tested period. Gene expression was categorized into four clusters according to the profiles of individual transcript accumulation. A majority of the genes encoding subunits of the respiratory complexes belonged to two major clusters, the time course of transcript accumulation of one cluster agreeing with that of respiratory development and the other remaining at high constant levels. The macroarray system devised in this study should be useful in monitoring mitochondrial biogenesis under various growth conditions and at different developmental stages in cereals.
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Affiliation(s)
- Sakina M Khanam
- Laboratory of Plant Genetics, Department of Agroenvironmental Science, Graduate School of Agricultural Science, Kobe University, Japan
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95
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Uyttewaal M, Mireau H, Rurek M, Hammani K, Arnal N, Quadrado M, Giegé P. PPR336 is Associated with Polysomes in Plant Mitochondria. J Mol Biol 2008; 375:626-36. [DOI: 10.1016/j.jmb.2007.11.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 11/02/2007] [Accepted: 11/05/2007] [Indexed: 11/30/2022]
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96
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Gonzalez DH, Welchen E, Attallah CV, Comelli RN, Mufarrege EF. Transcriptional coordination of the biogenesis of the oxidative phosphorylation machinery in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 51:105-16. [PMID: 17561924 DOI: 10.1111/j.1365-313x.2007.03121.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Publicly available microarray experiments were used to analyze Arabidopsis thaliana genes whose expression is correlated with that of nuclear genes encoding components of the oxidative phosphorylation machinery (OxPhos genes). This analysis indicated the existence of coordination in the expression of genes encoding components of the five respiratory complexes. For these genes, preferential expression was observed in anthers and roots, especially in the elongation zone, while reduced or very low relative expression was evident in leaves and mature pollen grains. A global induction of OxPhos genes by carbohydrates, photo-destruction of chloroplasts, inhibition of cellulose synthesis, release from dormancy and germination, among other conditions, was also observed. Cluster analysis of the response of Arabidopsis genes to a set of 15 treatments allowed the identification of DNA motifs, known as site II, that are frequently present in the upstream regions of genes with responses like those of OxPhos genes. Mutagenic analysis of site II motifs in several genes encoding respiratory chain components showed that they actively participate in transcription of these genes. We conclude that an important number of nuclear genes encoding components of the five respiratory complexes show coordinated expression under various circumstances, and that site II elements and the putative proteins that interact with them are, together with as yet unidentified factors, important actors in this coordinated response.
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Affiliation(s)
- Daniel H Gonzalez
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina.
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97
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Wormuth D, Heiber I, Shaikali J, Kandlbinder A, Baier M, Dietz KJ. Redox regulation and antioxidative defence in Arabidopsis leaves viewed from a systems biology perspective. J Biotechnol 2007; 129:229-48. [PMID: 17207878 DOI: 10.1016/j.jbiotec.2006.12.006] [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: 08/29/2006] [Revised: 11/11/2006] [Accepted: 12/04/2006] [Indexed: 12/18/2022]
Abstract
Redox regulation is a central control element in cell metabolism. It is employed to adjust photosynthesis and the antioxidant defence system of leaves to the prevailing environment. During recent years progress has been made in describing the redox-dependent alterations in metabolism, the thiol/disulfide proteome, the redox-dependent and cross-talking signalling pathways and the target genes of redox regulation. Some transcription factors have been identified as proteins that perform thiol/disulfide transitions linked to the redox-regulation of specific plant promoters. In addition first mathematical models have been designed to simulate antioxidant defence and predict its response. Taken together, a profound experimental data set has been generated which allows to approach a systems biology type of understanding of antioxidant defence in photosynthesising cells in the near future. Since oxidative stress is likely to limit plant growth under stress, such a systematic understanding of antioxidant defence will help to define novel targets for breeding stress-tolerant plants.
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Affiliation(s)
- Dennis Wormuth
- Biochemistry and Physiology of Plants, Faculty of Biology, W5, Bielefeld University, 33501 Bielefeld, Germany
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98
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Howell KA, Cheng K, Murcha MW, Jenkin LE, Millar AH, Whelan J. Oxygen initiation of respiration and mitochondrial biogenesis in rice. J Biol Chem 2007; 282:15619-31. [PMID: 17383966 DOI: 10.1074/jbc.m609866200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rice growth under aerobic and anaerobic conditions allowed aspects of mitochondrial biogenesis to be identified as dependent on or independent of an oxygen signal. Analysis of transcripts encoding mitochondrial components found that a subset of these genes respond to oxygen (defined as aerobic), whereas others are relatively unaffected by oxygen availability. Mitochondria formed during growth in anaerobic conditions had reduced protein levels of tricarboxylic acid cycle components and cytochrome-containing complexes of the respiratory chain and repressed respiratory functionality. In general, the capacity of the general import pathway was found to be significantly lower in mitochondria isolated from tissue grown under anaerobic conditions, whereas the carrier import pathway capacity was not affected by changes in oxygen availability. Transcript levels of genes encoding components of the protein import apparatus were generally not affected by the absence of oxygen, and their protein abundance was severalfold higher in mitochondria isolated from anaerobically grown tissue. However, both transcript and protein abundances of the subunits of the mitochondrial processing peptidase, which in plants is integrated into the cytochrome bc(1) complex, were repressed under anaerobic conditions. Therefore, in this system, an increase in import capacity is correlated with an increase in the abundance of the cytochrome bc(1) complex, which is ultimately dependent on the presence of oxygen, providing a link between the respiratory chain and protein import apparatus.
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Affiliation(s)
- Katharine A Howell
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia
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99
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Baxter CJ, Redestig H, Schauer N, Repsilber D, Patil KR, Nielsen J, Selbig J, Liu J, Fernie AR, Sweetlove LJ. The metabolic response of heterotrophic Arabidopsis cells to oxidative stress. PLANT PHYSIOLOGY 2007; 143:312-25. [PMID: 17122072 PMCID: PMC1761969 DOI: 10.1104/pp.106.090431] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 11/10/2006] [Indexed: 05/12/2023]
Abstract
To cope with oxidative stress, the metabolic network of plant cells must be reconfigured either to bypass damaged enzymes or to support adaptive responses. To characterize the dynamics of metabolic change during oxidative stress, heterotrophic Arabidopsis (Arabidopsis thaliana) cells were treated with menadione and changes in metabolite abundance and (13)C-labeling kinetics were quantified in a time series of samples taken over a 6 h period. Oxidative stress had a profound effect on the central metabolic pathways with extensive metabolic inhibition radiating from the tricarboxylic acid cycle and including large sectors of amino acid metabolism. Sequential accumulation of metabolites in specific pathways indicated a subsequent backing up of glycolysis and a diversion of carbon into the oxidative pentose phosphate pathway. Microarray analysis revealed a coordinated transcriptomic response that represents an emergency coping strategy allowing the cell to survive the metabolic hiatus. Rather than attempt to replace inhibited enzymes, transcripts encoding these enzymes are in fact down-regulated while an antioxidant defense response is mounted. In addition, a major switch from anabolic to catabolic metabolism is signaled. Metabolism is also reconfigured to bypass damaged steps (e.g. induction of an external NADH dehydrogenase of the mitochondrial respiratory chain). The overall metabolic response of Arabidopsis cells to oxidative stress is remarkably similar to the superoxide and hydrogen peroxide stimulons of bacteria and yeast (Saccharomyces cerevisiae), suggesting that the stress regulatory and signaling pathways of plants and microbes may share common elements.
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Affiliation(s)
- Charles J Baxter
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
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100
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Fernández-Silva P, Acín-Pérez R, Fernández-Vizarra E, Pérez-Martos A, Enriquez JA. In Vivo and In Organello Analyses of Mitochondrial Translation. Methods Cell Biol 2007; 80:571-88. [PMID: 17445714 DOI: 10.1016/s0091-679x(06)80028-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- P Fernández-Silva
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza 50013, Spain
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