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Gray MW, Burger G, Derelle R, Klimeš V, Leger MM, Sarrasin M, Vlček Č, Roger AJ, Eliáš M, Lang BF. The draft nuclear genome sequence and predicted mitochondrial proteome of Andalucia godoyi, a protist with the most gene-rich and bacteria-like mitochondrial genome. BMC Biol 2020; 18:22. [PMID: 32122349 PMCID: PMC7050145 DOI: 10.1186/s12915-020-0741-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023] Open
Abstract
Background Comparative analyses have indicated that the mitochondrion of the last eukaryotic common ancestor likely possessed all the key core structures and functions that are widely conserved throughout the domain Eucarya. To date, such studies have largely focused on animals, fungi, and land plants (primarily multicellular eukaryotes); relatively few mitochondrial proteomes from protists (primarily unicellular eukaryotic microbes) have been examined. To gauge the full extent of mitochondrial structural and functional complexity and to identify potential evolutionary trends in mitochondrial proteomes, more comprehensive explorations of phylogenetically diverse mitochondrial proteomes are required. In this regard, a key group is the jakobids, a clade of protists belonging to the eukaryotic supergroup Discoba, distinguished by having the most gene-rich and most bacteria-like mitochondrial genomes discovered to date. Results In this study, we assembled the draft nuclear genome sequence for the jakobid Andalucia godoyi and used a comprehensive in silico approach to infer the nucleus-encoded portion of the mitochondrial proteome of this protist, identifying 864 candidate mitochondrial proteins. The A. godoyi mitochondrial proteome has a complexity that parallels that of other eukaryotes, while exhibiting an unusually large number of ancestral features that have been lost particularly in opisthokont (animal and fungal) mitochondria. Notably, we find no evidence that the A. godoyi nuclear genome has or had a gene encoding a single-subunit, T3/T7 bacteriophage-like RNA polymerase, which functions as the mitochondrial transcriptase in all eukaryotes except the jakobids. Conclusions As genome and mitochondrial proteome data have become more widely available, a strikingly punctuate phylogenetic distribution of different mitochondrial components has been revealed, emphasizing that the pathways of mitochondrial proteome evolution are likely complex and lineage-specific. Unraveling this complexity will require comprehensive comparative analyses of mitochondrial proteomes from a phylogenetically broad range of eukaryotes, especially protists. The systematic in silico approach described here offers a valuable adjunct to direct proteomic analysis (e.g., via mass spectrometry), particularly in cases where the latter approach is constrained by sample limitation or other practical considerations.
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Affiliation(s)
- Michael W Gray
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Gertraud Burger
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
| | - Romain Derelle
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Vladimír Klimeš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Michelle M Leger
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.,Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain
| | - Matt Sarrasin
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
| | - Čestmír Vlček
- Current address: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - B Franz Lang
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
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Curi GC, Chan RL, Gonzalez DH. The leader intron of Arabidopsis thaliana genes encoding cytochrome c oxidase subunit 5c promotes high-level expression by increasing transcript abundance and translation efficiency. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:2563-71. [PMID: 16061502 DOI: 10.1093/jxb/eri250] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The involvement of regions located upstream of the translation start site in the expression of two Arabidopsis thaliana nuclear COX5c genes encoding subunit 5c of mitochondrial cytochrome c oxidase has been analysed. It was observed that these regions, which include a leader intron, direct the tissue-specific expression of the gus reporter gene, mainly in root and shoot meristems, actively growing tissues and vascular strands. Expression was also observed in flowers, specifically localized in anthers, stigma, and the receptacle, and in developing seeds. GUS activity measurements in protein extracts from transformed plants indicated that expression levels are higher than those observed with the constitutive CaMV 35S promoter. Removal of the leader intron produced a significant decrease in expression to values only slightly higher than those observed with a promoterless gus gene. Histochemical staining of plants transformed with the intronless construct revealed expression only in pollen, suggesting that regulatory elements capable of directing pollen-specific expression are present upstream of the intron. The COX5c-2 intron also increased GUS expression levels when fused in the correct orientation with the promoter of the unrelated COX5b-1 gene. Comparison of GUS activity values with the transcript levels suggests that the intron also increases translation efficiency of the corresponding mRNA. The results obtained point to an essential role of the intron present in the 5'-non-coding region of all known COX5c genes in directing the expression of these genes in plants.
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Affiliation(s)
- Graciela C Curi
- Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina
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Millar AH, Eubel H, Jänsch L, Kruft V, Heazlewood JL, Braun HP. Mitochondrial cytochrome c oxidase and succinate dehydrogenase complexes contain plant specific subunits. PLANT MOLECULAR BIOLOGY 2004; 56:77-90. [PMID: 15604729 DOI: 10.1007/s11103-004-2316-2] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Respiratory oxidative phosphorylation represents a central functionality in plant metabolism, but the subunit composition of the respiratory complexes in plants is still being defined. Most notably, complex II (succinate dehydrogenase) and complex IV (cytochrome c oxidase) are the least defined in plant mitochondria. Using Arabidopsis mitochondrial samples and 2D Blue-native/SDS-PAGE, we have separated complex II and IV from each other and displayed their individual subunits for analysis by tandem mass spectrometry and Edman sequencing. Complex II can be discretely separated from other complexes on Blue-native gels and consists of eight protein bands. It contains the four classical SDH subunits as well as four subunits unknown in mitochondria from other eukaryotes. Five of these proteins have previously been identified, while three are newly identified in this study. Complex IV consists of 9-10 protein bands, however, it is more diffuse in Blue-native gels and co-migrates in part with the translocase of the outer membrane (TOM) complex. Differential analysis of TOM and complex IV reveals that complex IV probably contains eight subunits with similarity to known complex IV subunits from other eukaryotes and a further six putative subunits which all represent proteins of unknown function in Arabidopsis . Comparison of the Arabidopsis data with Blue-native/SDS-PAGE separation of potato and bean mitochondria confirmed the protein band complexity of these two respiratory complexes in plants. Two-dimensional Blue-native/Blue-native PAGE, using digitonin followed by dodecylmaltoside in successive dimensions, separated a diffusely staining complex containing both TOM and complex IV. This suggests that the very similar mass of these complexes will likely prevent high purity separations based on size. The documented roles of several of the putative complex IV subunits in hypoxia response and ozone stress, and similarity between new complex II subunits and recently identified plant specific subunits of complex I, suggest novel biological insights can be gained from respiratory complex composition analysis.
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Affiliation(s)
- A Harvey Millar
- Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
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Ohtsu K, Nakazono M, Tsutsumi N, Hirai A. Characterization and expression of the genes for cytochrome c oxidase subunit VIb (COX6b) from rice and Arabidopsis thaliana. Gene 2001; 264:233-9. [PMID: 11250078 DOI: 10.1016/s0378-1119(01)00334-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many of the subunits of cytochrome c oxidase (COX) in the mitochondria of higher plants are encoded by nuclear genes. These genes are less characterized compared to mitochondrial-encoded genes. We previously isolated a cDNA encoding COX6b (designated OsCOX6b1 in this study) from the rice nuclear genome and analyzed its expression. The deduced protein had an extended N-terminus compared with human and yeast COX6b proteins. In this study, we identified another COX6b gene (OsCOX6b2) in rice and revealed that it was actually expressed. The deduced protein of this gene did not have an extended N-terminus and had about the same size as the human and yeast proteins. Genomic Southern hybridization analysis revealed that there was at least one OsCOX6b-homologus sequences in the rice genome other than OsCOX6b1 and OsCOX6b2. Furthermore, we identified three COX6b genes in a dicotyledonous plant, Arabidopsis thaliana. One of these genes (AtCOX6b1) was relatively long, with a length similar to that of OsCOX6b1, and the other two (AtCOX6b2 and AtCOX6b3) were shorter, with lengths similar to the length of OsCOX6b2. Genomic Southern hybridization analysis indicated there were no additional COX6b genes in the Arabidopsis genome. The coding regions of OsCOX6b1 and AtCOX6b1 were separated by four introns and those of OsCOX6b2, AtCOX6b2 and AtCOX6b3 were separated by three introns. A Northern hybridization analysis showed that OsCOX6b1, AtCOX6b1 and AtCOX6b3 were expressed in all organs examined, although with some differences in the amount of expression among the organs. OsCOX6b2 and AtCOX6b2 were strongly expressed in roots but most of the transcripts of AtCOX6b2 were degraded. The evolution of COX6b genes from rice and Arabidopsis is discussed.
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MESH Headings
- Amino Acid Sequence
- Arabidopsis/enzymology
- Arabidopsis/genetics
- Blotting, Northern
- Blotting, Southern
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Plant/chemistry
- DNA, Plant/genetics
- Electron Transport Complex IV/genetics
- Exons
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genes, Plant/genetics
- Introns
- Isoenzymes/genetics
- Molecular Sequence Data
- Oryza/enzymology
- Oryza/genetics
- Phylogeny
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
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Affiliation(s)
- K Ohtsu
- Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
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Adams KL, Daley DO, Qiu YL, Whelan J, Palmer JD. Repeated, recent and diverse transfers of a mitochondrial gene to the nucleus in flowering plants. Nature 2000; 408:354-7. [PMID: 11099041 DOI: 10.1038/35042567] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A central component of the endosymbiotic theory for the bacterial origin of the mitochondrion is that many of its genes were transferred to the nucleus. Most of this transfer occurred early in mitochondrial evolution; functional transfer of mitochondrial genes has ceased in animals. Although mitochondrial gene transfer continues to occur in plants, no comprehensive study of the frequency and timing of transfers during plant evolution has been conducted. Here we report frequent loss (26 times) and transfer to the nucleus of the mitochondrial gene rps10 among 277 diverse angiosperms. Characterization of nuclear rps10 genes from 16 out of 26 loss lineages implies that many independent, RNA-mediated rps10 transfers occurred during recent angiosperm evolution; each of the genes may represent a separate functional gene transfer. Thus, rps10 has been transferred to the nucleus at a surprisingly high rate during angiosperm evolution. The structures of several nuclear rps10 genes reveal diverse mechanisms by which transferred genes become activated, including parasitism of pre-existing nuclear genes for mitochondrial or cytoplasmic proteins, and activation without gain of a mitochondrial targeting sequence.
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Affiliation(s)
- K L Adams
- Department of Biology, Indiana University, Bloomington 47405, USA
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Hamanaka S, Ohtsu K, Kadowaki K, Nakazono M, Hirai A. Identification of cDNA encoding cytochrome c oxidase subunit 5c (COX5c) from rice: comparison of its expression with nuclear-encoded and mitochondrial-encoded COX genes. Genes Genet Syst 1999; 74:71-5. [PMID: 10586516 DOI: 10.1266/ggs.74.71] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Little is presently known about the nuclear-encoded genes for cytochrome c oxidase (COX) in higher plants. In rice, only the nuclear-encoded COX5b gene has been reported. To understand the relationship between the expression of nuclear-encoded and mitochondrial-encoded COX genes in rice, we first characterized a cDNA encoding one of the other nuclear COX genes, COX5c, which encodes 63 amino acids. The deduced amino acid sequence of COX5c from rice was highly homologous to that from sweet potato. Genomic Southern hybridization indicated that the rice COX5c subunit is encoded by a single copy of the COX5c gene. Furthermore, we compared the expression patterns of the nuclear-encoded COX5c and COX5b genes with the expression pattern of the mitochondrial-encoded COX1 gene among several organs by Northern blot analysis. The results suggested that regulatory systems of expression between the nuclear-encoded and the mitochondrial-encoded COX genes are different among different organs in rice.
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Affiliation(s)
- S Hamanaka
- Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, Japan
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Emmermann M, Braun HP, Schmitz UK. The ADP/ATP translocator from potato has a long amino-terminal extension. Curr Genet 1991; 20:405-10. [PMID: 1807831 DOI: 10.1007/bf00317069] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ADP/ATP translocator is an abundant protein of the mitochondrial inner membrane, which in fungi and mammals is synthesized without a presequence. Here we report that the translocator from potato has an amino-terminal extension which may function in mitochondrial targeting. Several cDNA clones encoding the nucleotide sequence of the ADP/ATP translocator have been isolated from potato leaf and tuber cDNA libraries constructed in lambda phages. Only one class of cDNA clones was found but possibly different translocator genes are expressed in other tissues. High levels of transcripts for the translocator are found in all tissues analysed. Sequence determination of the complete insert of one of the clones reveals a long open reading frame of 1158 bp encoding a protein of 386 amino acids corresponding to a calculated molecular weight of 42 kDa. In contrast, the ADP/ATP translocator proteins from fungi and mammals are significantly smaller. Comparison of the Neurospora translocator with the potato protein shows about 75% sequence homology, being confined to the region after amino acid 85 of the potato polypeptide. Antibodies directed against the fungal translocator recognize a protein of 30 kDa in the inner membrane of potato mitochondria, suggesting that the mature protein has a similar size as the translocators from fungi and mammals. Thus, the additional segment of the potato ADP/ATP translocator forms an amino-terminal extension which may be involved in the import of the protein into plant mitochondria.
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Affiliation(s)
- M Emmermann
- Institut für Genbiologische Forschung Berlin GmbH, Federal Republic of Germany
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