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Mao XL, Eriani G, Zhou XL. ADATs: roles in tRNA editing and relevance to disease. Acta Biochim Biophys Sin (Shanghai) 2024. [PMID: 39034823 DOI: 10.3724/abbs.2024125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024] Open
Abstract
Transfer RNAs (tRNAs) play central roles in protein biosynthesis. Post-transcriptional RNA modifications affect tRNA function and stability. Among these modifications, RNA editing is a widespread RNA modification in three domains of life. Proteins of the adenosine deaminase acting on tRNA (ADAT) family were discovered more than 20 years ago. They catalyze the deamination of adenosine to inosine (A-to-I) or cytidine to uridine (C-to-U) during tRNA maturation. The most studied example is the TadA- or ADAT2/3-mediated A-to-I conversion of the tRNA wobble position in the anticodon of prokaryotic or eukaryotic tRNAs, respectively. This review provides detailed information on A-to-I and C-to-U editing of tRNAs in different domains of life, presents recent new findings on ADATs for DNA editing, and finally comments on the association of mutations in the ADAT3 gene with intellectual disability.
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Affiliation(s)
- Xue-Ling Mao
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, 2 allée Konrad Roentgen, 67084 Strasbourg, France
| | - Xiao-Long Zhou
- Key Laboratory of RNA Innovation, Science and Engineering, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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2
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Afonin DA, Gerasimov ES, Škodová-Sveráková I, Záhonová K, Gahura O, Albanaz ATS, Myšková E, Bykova A, Paris Z, Lukeš J, Opperdoes FR, Horváth A, Zimmer SL, Yurchenko V. Blastocrithidia nonstop mitochondrial genome and its expression are remarkably insulated from nuclear codon reassignment. Nucleic Acids Res 2024; 52:3870-3885. [PMID: 38452217 DOI: 10.1093/nar/gkae168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/09/2024] Open
Abstract
The canonical stop codons of the nuclear genome of the trypanosomatid Blastocrithidia nonstop are recoded. Here, we investigated the effect of this recoding on the mitochondrial genome and gene expression. Trypanosomatids possess a single mitochondrion and protein-coding transcripts of this genome require RNA editing in order to generate open reading frames of many transcripts encoded as 'cryptogenes'. Small RNAs that can number in the hundreds direct editing and produce a mitochondrial transcriptome of unusual complexity. We find B. nonstop to have a typical trypanosomatid mitochondrial genetic code, which presumably requires the mitochondrion to disable utilization of the two nucleus-encoded suppressor tRNAs, which appear to be imported into the organelle. Alterations of the protein factors responsible for mRNA editing were also documented, but they have likely originated from sources other than B. nonstop nuclear genome recoding. The population of guide RNAs directing editing is minimal, yet virtually all genes for the plethora of known editing factors are still present. Most intriguingly, despite lacking complex I cryptogene guide RNAs, these cryptogene transcripts are stochastically edited to high levels.
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MESH Headings
- Genome, Mitochondrial
- RNA Editing
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Open Reading Frames/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Trypanosomatina/genetics
- Trypanosomatina/metabolism
- Codon/genetics
- Mitochondria/genetics
- Mitochondria/metabolism
- Codon, Terminator/genetics
- RNA, Guide, Kinetoplastida/genetics
- RNA, Guide, Kinetoplastida/metabolism
- Genetic Code
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
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Affiliation(s)
- Dmitry A Afonin
- Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Evgeny S Gerasimov
- Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051, Russia
| | - Ingrid Škodová-Sveráková
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Kristína Záhonová
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV 252 50 Vestec, Czechia
- Division of Infectious Diseases, Department of Medicine, University of Alberta, T6G 2R3 Edmonton, Alberta, Canada
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Amanda T S Albanaz
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Eva Myšková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Anastassia Bykova
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czechia
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czechia
| | - Fred R Opperdoes
- De Duve Institute, Université Catholique de Louvain, 1200 Brussels, Belgium
| | - Anton Horváth
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia
| | - Sara L Zimmer
- University of Minnesota Medical School, Duluth Campus, Duluth, MN 55812, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
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3
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Ahuja N, Cao X, Schultz DT, Picciani N, Lord A, Shao S, Jia K, Burdick DR, Haddock SHD, Li Y, Dunn CW. Giants among Cnidaria: Large Nuclear Genomes and Rearranged Mitochondrial Genomes in Siphonophores. Genome Biol Evol 2024; 16:evae048. [PMID: 38502059 PMCID: PMC10980510 DOI: 10.1093/gbe/evae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 02/20/2024] [Accepted: 03/07/2024] [Indexed: 03/20/2024] Open
Abstract
Siphonophores (Cnidaria: Hydrozoa) are abundant predators found throughout the ocean and are important constituents of the global zooplankton community. They range in length from a few centimeters to tens of meters. They are gelatinous, fragile, and difficult to collect, so many aspects of the biology of these roughly 200 species remain poorly understood. To survey siphonophore genome diversity, we performed Illumina sequencing of 32 species sampled broadly across the phylogeny. Sequencing depth was sufficient to estimate nuclear genome size from k-mer spectra in six specimens, ranging from 0.7 to 2.3 Gb, with heterozygosity estimates between 0.69% and 2.32%. Incremental k-mer counting indicates k-mer peaks can be absent with nearly 20× read coverage, suggesting minimum genome sizes range from 1.4 to 5.6 Gb in the 25 samples without peaks in the k-mer spectra. This work confirms most siphonophore nuclear genomes are large relative to the genomes of other cnidarians, but also identifies several with reduced size that are tractable targets for future siphonophore nuclear genome assembly projects. We also assembled complete mitochondrial genomes for 33 specimens from these new data, indicating a conserved gene order shared among nonsiphonophore hydrozoans, Cystonectae, and some Physonectae, revealing the ancestral mitochondrial gene order of siphonophores. Our results also suggest extensive rearrangement of mitochondrial genomes within other Physonectae and in Calycophorae. Though siphonophores comprise a small fraction of cnidarian species, this survey greatly expands our understanding of cnidarian genome diversity. This study further illustrates both the importance of deep phylogenetic sampling and the utility of k-mer-based genome skimming in understanding the genomic diversity of a clade.
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Affiliation(s)
- Namrata Ahuja
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Xuwen Cao
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Darrin T Schultz
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Natasha Picciani
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Arianna Lord
- Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Shengyuan Shao
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Kejue Jia
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | | | - Yuanning Li
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Casey W Dunn
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
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Anuntasomboon P, Siripattanapipong S, Unajak S, Choowongkomon K, Burchmore R, Leelayoova S, Mungthin M, E-Kobon T. Identification of a unique conserved region from a kinetoplastid genome of Leishmania orientalis (formerly named Leishmania siamensis) strain PCM2 in Thailand. Sci Rep 2023; 13:19644. [PMID: 37950023 PMCID: PMC10638283 DOI: 10.1038/s41598-023-46638-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023] Open
Abstract
Mitochondrial DNAs (mtDNAs) appear in almost all eukaryotic species and are useful molecular markers for phylogenetic studies and species identification. Kinetoplast DNAs (kDNAs) are structurally complex circular mtDNA networks in kinetoplastids, divided into maxicircles and minicircles. Despite several kDNAs of many Leishmania species being examined, the kDNAs of the new species, Leishmania orientalis (formerly named Leishmania siamensis) strain PCM2, have not been explored. This study aimed to investigate the maxicircle and minicircle DNAs of L. orientalis strain PCM2 using hybrid genome sequencing technologies and bioinformatic analyses. The kDNA sequences were isolated and assembled using the SPAdes hybrid assembler from the Illumina short-read and PacBio long-read data. Circular contigs of the maxicircle and minicircle DNAs were reconstructed and confirmed by BLASTn and rKOMICs programs. The kDNA genome was annotated by BLASTn before the genome comparison and phylogenetic analysis by progressiveMauve, MAFFT, and MEGA programs. The maxicircle of L. orientalis strain PCM2 (18,215 bp) showed 99.92% similarity and gene arrangement to Leishmania enriettii strain LEM3045 maxicircle with variation in the 12s rRNA gene and divergent region. Phylogenetics of the whole sequence, coding regions, divergent regions, and 12s rRNA gene also confirmed this relationship and subgenera separation. The identified 105 classes of minicircles (402-1177 bp) were clustered monophyletically and related to the Leishmania donovani minicircles. The kinetoplast maxicircle and minicircle DNAs of L. orientalis strain PCM2 contained a unique conserved region potentially useful for specific diagnosis of L. orientalis and further exploration of this parasite population genetics in Thailand and related regions.
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Affiliation(s)
- Pornchai Anuntasomboon
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand
| | | | - Sasimanas Unajak
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | | | - Richard Burchmore
- Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Saovanee Leelayoova
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Teerasak E-Kobon
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand.
- Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand.
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Kachale A, Pavlíková Z, Nenarokova A, Roithová A, Durante IM, Miletínová P, Záhonová K, Nenarokov S, Votýpka J, Horáková E, Ross RL, Yurchenko V, Beznosková P, Paris Z, Valášek LS, Lukeš J. Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment. Nature 2023; 613:751-758. [PMID: 36631608 DOI: 10.1038/s41586-022-05584-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 11/18/2022] [Indexed: 01/13/2023]
Abstract
Cognate tRNAs deliver specific amino acids to translating ribosomes according to the standard genetic code, and three codons with no cognate tRNAs serve as stop codons. Some protists have reassigned all stop codons as sense codons, neglecting this fundamental principle1-4. Here we analyse the in-frame stop codons in 7,259 predicted protein-coding genes of a previously undescribed trypanosomatid, Blastocrithidia nonstop. We reveal that in this species in-frame stop codons are underrepresented in genes expressed at high levels and that UAA serves as the only termination codon. Whereas new tRNAsGlu fully cognate to UAG and UAA evolved to reassign these stop codons, the UGA reassignment followed a different path through shortening the anticodon stem of tRNATrpCCA from five to four base pairs (bp). The canonical 5-bp tRNATrp recognizes UGG as dictated by the genetic code, whereas its shortened 4-bp variant incorporates tryptophan also into in-frame UGA. Mimicking this evolutionary twist by engineering both variants from B. nonstop, Trypanosoma brucei and Saccharomyces cerevisiae and expressing them in the last two species, we recorded a significantly higher readthrough for all 4-bp variants. Furthermore, a gene encoding B. nonstop release factor 1 acquired a mutation that specifically restricts UGA recognition, robustly potentiating the UGA reassignment. Virtually the same strategy has been adopted by the ciliate Condylostoma magnum. Hence, we describe a previously unknown, universal mechanism that has been exploited in unrelated eukaryotes with reassigned stop codons.
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Affiliation(s)
- Ambar Kachale
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Zuzana Pavlíková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Adriana Roithová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Ignacio M Durante
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Petra Miletínová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Serafim Nenarokov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Jan Votýpka
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Institute of Microbiology, Czech Academy of Sciences, Třeboň, Czech Republic
| | | | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Petra Beznosková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
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6
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Anuntasomboon P, Siripattanapipong S, Unajak S, Choowongkomon K, Burchmore R, Leelayoova S, Mungthin M, E-kobon T. Identification of a conserved maxicircle and unique minicircles as part of the mitochondrial genome of Leishmania martiniquensis strain PCM3 in Thailand. Parasit Vectors 2022; 15:459. [PMID: 36510327 PMCID: PMC9743726 DOI: 10.1186/s13071-022-05592-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The mitochondrial DNA of trypanosomatids, including Leishmania, is known as kinetoplast DNAs (kDNAs). The kDNAs form networks of hundreds of DNA circles that are evidently interlocked and require complex RNA editing. Previous studies showed that kDNA played a role in drug resistance, adaptation, and survival of Leishmania. Leishmania martiniquensis is one of the most frequently observed species in Thailand, and its kDNAs have not been illustrated. METHODS This study aimed to extract the kDNA sequences from Illumina short-read and PacBio long-read whole-genome sequence data of L. martiniquensis strain PCM3 priorly isolated from the southern province of Thailand. A circular maxicircle DNA was reconstructed by de novo assembly using the SPAdes program, while the minicircle sequences were retrieved and assembled by the rKOMIC tool. The kDNA contigs were confirmed by blasting to the NCBI database, followed by comparative genomic and phylogenetic analysis. RESULTS We successfully constructed the complete circular sequence of the maxicircle (19,008 bp) and 214 classes of the minicircles from L. martiniquensis strain PCM3. The genome comparison and annotation showed that the maxicircle structure of L. martiniquensis strain PCM3 was similar to those of L. enriettii strain LEM3045 (84.29%), L. arabica strain LEM1108 (82.79%), and L. tarentolae (79.2%). Phylogenetic analysis also showed unique evolution of the minicircles of L. martiniquensis strain PCM3 from other examined Leishmania species. CONCLUSIONS This was the first report of the complete maxicircle and 214 minicircles of L. martiniquensis strain PCM3 using integrated whole-genome sequencing data. The information will be helpful for further improvement of diagnosis methods and monitoring genetic diversity changes of this parasite.
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Affiliation(s)
- Pornchai Anuntasomboon
- grid.9723.f0000 0001 0944 049XDepartment of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand ,grid.9723.f0000 0001 0944 049XOmics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand
| | - Suradej Siripattanapipong
- grid.10223.320000 0004 1937 0490Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sasimanas Unajak
- grid.9723.f0000 0001 0944 049XDepartment of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Kiattawee Choowongkomon
- grid.9723.f0000 0001 0944 049XDepartment of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Richard Burchmore
- grid.8756.c0000 0001 2193 314XGlasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Saovanee Leelayoova
- grid.10223.320000 0004 1937 0490Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Mathirut Mungthin
- grid.10223.320000 0004 1937 0490Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Teerasak E-kobon
- grid.9723.f0000 0001 0944 049XDepartment of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand ,grid.9723.f0000 0001 0944 049XOmics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand
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7
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Paris Z, Svobodová M, Kachale A, Horáková E, Nenarokova A, Lukeš J. A mitochondrial cytidine deaminase is responsible for C to U editing of tRNA Trp to decode the UGA codon in Trypanosoma brucei. RNA Biol 2021; 18:278-286. [PMID: 34224320 PMCID: PMC8677022 DOI: 10.1080/15476286.2021.1940445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In kinetoplastid protists, all mitochondrial tRNAs are encoded in the nucleus and imported from the cytoplasm to maintain organellar translation. This also applies to the tryptophanyl tRNA (tRNATrp) encoded by a single-copy nuclear gene, with a CCA anticodon to read UGG codon used in the cytosolic translation. Yet, in the mitochondrion it is unable to decode the UGA codon specifying tryptophan. Following mitochondrial import of tRNATrp, this problem is solved at the RNA level by a single C34 to U34 editing event that creates the UCA anticodon, recognizing UGA. To identify the enzyme responsible for this critical editing activity, we scrutinized the genome of Trypanosoma brucei for putative cytidine deaminases as the most likely candidates. Using RNAi silencing and poisoned primer extension, we have identified a novel deaminase enzyme, named here TbmCDAT for mitochondrial Cytidine Deaminase Acting on tRNA, which is responsible for this organelle-specific activity in T. brucei. The ablation of TbmCDAT led to the downregulation of mitochondrial protein synthesis, supporting its role in decoding the UGA tryptophan codon.
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Affiliation(s)
- Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Budweis, Czech Republic
| | - Michaela Svobodová
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic
| | - Ambar Kachale
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Budweis, Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Science, České Budějovice, Budweis, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Budweis, Czech Republic
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8
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Ceriotti LF, Roulet ME, Sanchez-Puerta MV. Plastomes in the holoparasitic family Balanophoraceae: Extremely high AT content, severe gene content reduction, and two independent genetic code changes. Mol Phylogenet Evol 2021; 162:107208. [PMID: 34029719 DOI: 10.1016/j.ympev.2021.107208] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 05/11/2021] [Accepted: 05/19/2021] [Indexed: 12/29/2022]
Abstract
The transition to a heterotrophic lifestyle in angiosperms is characterized by convergent evolutionary changes. Plastid genome remodeling includes dramatic functional and physical reductions with the highest degrees observed in fully heterotrophic plants. Genes related to photosynthesis are generally absent or pseudogenized, while a few genes related to other metabolic processes that take place within the plastid are almost invariably maintained. The family Balanophoraceae consists of root holoparasites that present reduced plastid genomes with an extraordinarily elevated AT content and the single genetic code change ever documented in land plant plastomes (the stop codon TAG now codes for tryptophan). Here, we studied the plastomes of Lophophytum leandri and Ombrophytum subterraneum (Balanophoraceae) that showed the remarkable absence of the gene trnE, a highly biased nucleotide composition, and an independent genetic code change (the standard stop codon TGA codes for tryptophan). This is the second genetic code change identified in land plant plastomes. Analysis of the transcriptome of Lophophytum indicated that the entire C5 pathway typical of plants is conserved despite the lack of trnE in its plastome. A hypothetical model of plastome evolution in the Balanophoraceae is presented.
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Affiliation(s)
- Luis Federico Ceriotti
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina; Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA Mendoza, Argentina
| | - M Emilia Roulet
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina
| | - M Virginia Sanchez-Puerta
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina; Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA Mendoza, Argentina.
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9
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Záhonová K, Lax G, Sinha SD, Leonard G, Richards TA, Lukeš J, Wideman JG. Single-cell genomics unveils a canonical origin of the diverse mitochondrial genomes of euglenozoans. BMC Biol 2021; 19:103. [PMID: 34001130 PMCID: PMC8130358 DOI: 10.1186/s12915-021-01035-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/22/2021] [Indexed: 12/28/2022] Open
Abstract
Background The supergroup Euglenozoa unites heterotrophic flagellates from three major clades, kinetoplastids, diplonemids, and euglenids, each of which exhibits extremely divergent mitochondrial characteristics. Mitochondrial genomes (mtDNAs) of euglenids comprise multiple linear chromosomes carrying single genes, whereas mitochondrial chromosomes are circular non-catenated in diplonemids, but circular and catenated in kinetoplastids. In diplonemids and kinetoplastids, mitochondrial mRNAs require extensive and diverse editing and/or trans-splicing to produce mature transcripts. All known euglenozoan mtDNAs exhibit extremely short mitochondrial small (rns) and large (rnl) subunit rRNA genes, and absence of tRNA genes. How these features evolved from an ancestral bacteria-like circular mitochondrial genome remains unanswered. Results We sequenced and assembled 20 euglenozoan single-cell amplified genomes (SAGs). In our phylogenetic and phylogenomic analyses, three SAGs were placed within kinetoplastids, 14 within diplonemids, one (EU2) within euglenids, and two SAGs with nearly identical small subunit rRNA gene (18S) sequences (EU17/18) branched as either a basal lineage of euglenids, or as a sister to all euglenozoans. Near-complete mitochondrial genomes were identified in EU2 and EU17/18. Surprisingly, both EU2 and EU17/18 mitochondrial contigs contained multiple genes and one tRNA gene. Furthermore, EU17/18 mtDNA possessed several features unique among euglenozoans including full-length rns and rnl genes, six mitoribosomal genes, and nad11, all likely on a single chromosome. Conclusions Our data strongly suggest that EU17/18 is an early-branching euglenozoan with numerous ancestral mitochondrial features. Collectively these data contribute to untangling the early evolution of euglenozoan mitochondria. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01035-y.
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Affiliation(s)
- Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Gordon Lax
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Savar D Sinha
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, USA
| | - Guy Leonard
- Department of Zoology, University of Oxford, Oxford, UK
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
| | - Jeremy G Wideman
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, USA.
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10
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Berg MD, Brandl CJ. Transfer RNAs: diversity in form and function. RNA Biol 2021; 18:316-339. [PMID: 32900285 PMCID: PMC7954030 DOI: 10.1080/15476286.2020.1809197] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/31/2020] [Accepted: 08/08/2020] [Indexed: 12/11/2022] Open
Abstract
As the adaptor that decodes mRNA sequence into protein, the basic aspects of tRNA structure and function are central to all studies of biology. Yet the complexities of their properties and cellular roles go beyond the view of tRNAs as static participants in protein synthesis. Detailed analyses through more than 60 years of study have revealed tRNAs to be a fascinatingly diverse group of molecules in form and function, impacting cell biology, physiology, disease and synthetic biology. This review analyzes tRNA structure, biosynthesis and function, and includes topics that demonstrate their diversity and growing importance.
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Affiliation(s)
- Matthew D. Berg
- Department of Biochemistry, The University of Western Ontario, London, Canada
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11
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Wolff P, Villette C, Zumsteg J, Heintz D, Antoine L, Chane-Woon-Ming B, Droogmans L, Grosjean H, Westhof E. Comparative patterns of modified nucleotides in individual tRNA species from a mesophilic and two thermophilic archaea. RNA (NEW YORK, N.Y.) 2020; 26:1957-1975. [PMID: 32994183 PMCID: PMC7668247 DOI: 10.1261/rna.077537.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/09/2020] [Indexed: 05/22/2023]
Abstract
To improve and complete our knowledge of archaeal tRNA modification patterns, we have identified and compared the modification pattern (type and location) in tRNAs of three very different archaeal species, Methanococcus maripaludis (a mesophilic methanogen), Pyrococcus furiosus (a hyperthermophile thermococcale), and Sulfolobus acidocaldarius (an acidophilic thermophilic sulfolobale). Most abundant isoacceptor tRNAs (79 in total) for each of the 20 amino acids were isolated by two-dimensional gel electrophoresis followed by in-gel RNase digestions. The resulting oligonucleotide fragments were separated by nanoLC and their nucleotide content analyzed by mass spectrometry (MS/MS). Analysis of total modified nucleosides obtained from complete digestion of bulk tRNAs was also performed. Distinct base- and/or ribose-methylations, cytidine acetylations, and thiolated pyrimidines were identified, some at new positions in tRNAs. Novel, some tentatively identified, modifications were also found. The least diversified modification landscape is observed in the mesophilic Methanococcus maripaludis and the most complex one in Sulfolobus acidocaldarius Notable observations are the frequent occurrence of ac4C nucleotides in thermophilic archaeal tRNAs, the presence of m7G at positions 1 and 10 in Pyrococcus furiosus tRNAs, and the use of wyosine derivatives at position 37 of tRNAs, especially those decoding U1- and C1-starting codons. These results complete those already obtained by others with sets of archaeal tRNAs from Methanocaldococcus jannaschii and Haloferax volcanii.
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Affiliation(s)
- Philippe Wolff
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Claire Villette
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Julie Zumsteg
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Laura Antoine
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Béatrice Chane-Woon-Ming
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
| | - Louis Droogmans
- Laboratoire de Chimie Biologique, Université Libre de Bruxelles, Institut Labiris, B-1070, Belgium
| | - Henri Grosjean
- Laboratoire de Chimie Biologique, Université Libre de Bruxelles, Institut Labiris, B-1070, Belgium
| | - Eric Westhof
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084, Strasbourg, France
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12
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Accornero F, Ross RL, Alfonzo JD. From canonical to modified nucleotides: balancing translation and metabolism. Crit Rev Biochem Mol Biol 2020; 55:525-540. [PMID: 32933330 DOI: 10.1080/10409238.2020.1818685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Every type of nucleic acid in cells may undergo some kind of post-replicative or post-transcriptional chemical modification. Recent evidence has highlighted their importance in biology and their chemical complexity. In the following pages, we will describe new discoveries of modifications, with a focus on tRNA and mRNA. We will highlight current challenges and advances in modification detection and we will discuss how changes in nucleotide post-transcriptional modifications may affect cell homeostasis leading to malfunction. Although, RNA modifications prevail in all forms of life, the present review will focus on eukaryotic systems, where the great degree of intracellular compartmentalization provides barriers and filters for the level at which a given RNA is modified and will of course affect its fate and function. Additionally, although we will mention rRNA modification and modifications of the mRNA 5'-CAP structure, this will only be discussed in passing, as many substantive reviews have been written on these subjects. Here we will not spend much time describing all the possible modifications that have been observed; truly a daunting task. For reference, Bujnicki and coworkers have created MODOMICS, a useful repository for all types of modifications and their associated enzymes. Instead we will discuss a few examples, which illustrate our arguments on the connection of modifications, metabolism and ultimately translation. The fact remains, a full understanding of the long reach of nucleic acid modifications in cells requires both a global and targeted study of unprecedented scale, which at the moment may well be limited only by technology.
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Affiliation(s)
- Federica Accornero
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA.,The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Robert L Ross
- Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, OH, USA
| | - Juan D Alfonzo
- The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, USA
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13
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A search for the physical basis of the genetic code. Biosystems 2020; 195:104148. [DOI: 10.1016/j.biosystems.2020.104148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 01/01/2023]
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14
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Shikha S, Schneider A. The single CCA-adding enzyme of T. brucei has distinct functions in the cytosol and in mitochondria. J Biol Chem 2020; 295:6138-6150. [PMID: 32234763 DOI: 10.1074/jbc.ra119.011877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/23/2020] [Indexed: 12/27/2022] Open
Abstract
tRNAs universally carry a CCA nucleotide triplet at their 3'-ends. In eukaryotes, the CCA is added post-transcriptionally by the CCA-adding enzyme (CAE). The mitochondrion of the parasitic protozoan Trypanosoma brucei lacks tRNA genes and therefore imports all of its tRNAs from the cytosol. This has generated interest in the tRNA modifications and their distribution in this organism, including how CCA is added to tRNAs. Here, using a BLAST search for genes encoding putative CAE proteins in T. brucei, we identified a single ORF, Tb927.9.8780, as a potential candidate. Knockdown of this putative protein, termed TbCAE, resulted in the accumulation of truncated tRNAs, abolished translation, and inhibited both total and mitochondrial CCA-adding activities, indicating that TbCAE is located both in the cytosol and mitochondrion. However, mitochondrially localized tRNAs were much less affected by the TbCAE ablation than the other tRNAs. Complementation assays revealed that the N-terminal 10 amino acids of TbCAE are dispensable for its activity and mitochondrial localization and that deletion of 10 further amino acids abolishes both. A growth arrest caused by the TbCAE knockdown was rescued by the expression of the cytosolic isoform of yeast CAE, even though it was not imported into mitochondria. This finding indicated that the yeast enzyme complements the essential function of TbCAE by adding CCA to the primary tRNA transcripts. Of note, ablation of the mitochondrial TbCAE activity, which likely has a repair function, only marginally affected growth.
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Affiliation(s)
- Shikha Shikha
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
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15
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Warren JM, Sloan DB. Interchangeable parts: The evolutionarily dynamic tRNA population in plant mitochondria. Mitochondrion 2020; 52:144-156. [PMID: 32184120 DOI: 10.1016/j.mito.2020.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/06/2020] [Accepted: 03/11/2020] [Indexed: 01/31/2023]
Abstract
Transfer RNAs (tRNAs) remain one of the very few classes of genes still encoded in the mitochondrial genome. These key components of the protein translation system must interact with a large enzymatic network of nuclear-encoded gene products to maintain mitochondrial function. Plants have an evolutionarily dynamic mitochondrial tRNA population, including ongoing tRNA gene loss and replacement by both horizontal gene transfer from diverse sources and import of nuclear-expressed tRNAs from the cytosol. Thus, plant mitochondria represent an excellent model for understanding how anciently divergent genes can act as "interchangeable parts" during the evolution of complex molecular systems. In particular, understanding the integration of the mitochondrial translation system with elements of the corresponding machinery used in cytosolic protein synthesis is a key area for eukaryotic cellular evolution. Here, we review the increasingly detailed phylogenetic data about the evolutionary history of mitochondrial tRNA gene loss, transfer, and functional replacement that has created extreme variation in mitochondrial tRNA populations across plant species. We describe emerging tRNA-seq methods with promise for refining our understanding of the expression and subcellular localization of tRNAs. Finally, we summarize current evidence and identify open questions related to coevolutionary changes in nuclear-encoded enzymes that have accompanied turnover in mitochondrial tRNA populations.
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Affiliation(s)
- Jessica M Warren
- Department of Biology, Colorado State University, Fort Collins, CO, USA.
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO, USA
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16
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Guo Q, Ng PQ, Shi S, Fan D, Li J, Zhao J, Wang H, David R, Mittal P, Do T, Bock R, Zhao M, Zhou W, Searle I. Arabidopsis TRM5 encodes a nuclear-localised bifunctional tRNA guanine and inosine-N1-methyltransferase that is important for growth. PLoS One 2019; 14:e0225064. [PMID: 31756231 PMCID: PMC6874348 DOI: 10.1371/journal.pone.0225064] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/28/2019] [Indexed: 12/30/2022] Open
Abstract
Modified nucleosides in tRNAs are critical for protein translation. N1-methylguanosine-37 and N1-methylinosine-37 in tRNAs, both located at the 3'-adjacent to the anticodon, are formed by Trm5. Here we describe Arabidopsis thaliana AtTRM5 (At3g56120) as a Trm5 ortholog. Attrm5 mutant plants have overall slower growth as observed by slower leaf initiation rate, delayed flowering and reduced primary root length. In Attrm5 mutants, mRNAs of flowering time genes are less abundant and correlated with delayed flowering. We show that AtTRM5 complements the yeast trm5 mutant, and in vitro methylates tRNA guanosine-37 to produce N1-methylguanosine (m1G). We also show in vitro that AtTRM5 methylates tRNA inosine-37 to produce N1-methylinosine (m1I) and in Attrm5 mutant plants, we show a reduction of both N1-methylguanosine and N1-methylinosine. We also show that AtTRM5 is localized to the nucleus in plant cells. Proteomics data showed that photosynthetic protein abundance is affected in Attrm5 mutant plants. Finally, we show tRNA-Ala aminoacylation is not affected in Attrm5 mutants. However the abundance of tRNA-Ala and tRNA-Asp 5' half cleavage products are deduced. Our findings highlight the bifunctionality of AtTRM5 and the importance of the post-transcriptional tRNA modifications m1G and m1I at tRNA position 37 in general plant growth and development.
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Affiliation(s)
- Qianqian Guo
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Pei Qin Ng
- School of Biological Sciences, School of Agriculture, Food and Wine, The University of Adelaide and Shanghai Jiao Tong University Joint International Centre for Agriculture and Health, The University of Adelaide, Adelaide, Adelaide, Australia
| | - Shanshan Shi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Diwen Fan
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jun Li
- School of Biological Sciences, School of Agriculture, Food and Wine, The University of Adelaide and Shanghai Jiao Tong University Joint International Centre for Agriculture and Health, The University of Adelaide, Adelaide, Adelaide, Australia
| | - Jing Zhao
- School of Biological Sciences, School of Agriculture, Food and Wine, The University of Adelaide and Shanghai Jiao Tong University Joint International Centre for Agriculture and Health, The University of Adelaide, Adelaide, Adelaide, Australia
| | - Hua Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Rakesh David
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Adelaide, Australia
| | - Parul Mittal
- Adelaide Proteomics Centre, School of Biological Sciences, The University of Adelaide, SA, Australia
| | - Trung Do
- School of Biological Sciences, School of Agriculture, Food and Wine, The University of Adelaide and Shanghai Jiao Tong University Joint International Centre for Agriculture and Health, The University of Adelaide, Adelaide, Adelaide, Australia
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Ming Zhao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wenbin Zhou
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Iain Searle
- School of Biological Sciences, School of Agriculture, Food and Wine, The University of Adelaide and Shanghai Jiao Tong University Joint International Centre for Agriculture and Health, The University of Adelaide, Adelaide, Adelaide, Australia
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17
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Noutahi E, Calderon V, Blanchette M, El-Mabrouk N, Lang BF. Rapid Genetic Code Evolution in Green Algal Mitochondrial Genomes. Mol Biol Evol 2019; 36:766-783. [PMID: 30698742 PMCID: PMC6551751 DOI: 10.1093/molbev/msz016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Genetic code deviations involving stop codons have been previously reported in mitochondrial genomes of several green plants (Viridiplantae), most notably chlorophyte algae (Chlorophyta). However, as changes in codon recognition from one amino acid to another are more difficult to infer, such changes might have gone unnoticed in particular lineages with high evolutionary rates that are otherwise prone to codon reassignments. To gain further insight into the evolution of the mitochondrial genetic code in green plants, we have conducted an in-depth study across mtDNAs from 51 green plants (32 chlorophytes and 19 streptophytes). Besides confirming known stop-to-sense reassignments, our study documents the first cases of sense-to-sense codon reassignments in Chlorophyta mtDNAs. In several Sphaeropleales, we report the decoding of AGG codons (normally arginine) as alanine, by tRNA(CCU) of various origins that carry the recognition signature for alanine tRNA synthetase. In Chromochloris, we identify tRNA variants decoding AGG as methionine and the synonymous codon CGG as leucine. Finally, we find strong evidence supporting the decoding of AUA codons (normally isoleucine) as methionine in Pycnococcus. Our results rely on a recently developed conceptual framework (CoreTracker) that predicts codon reassignments based on the disparity between DNA sequence (codons) and the derived protein sequence. These predictions are then validated by an evaluation of tRNA phylogeny, to identify the evolution of new tRNAs via gene duplication and loss, and structural modifications that lead to the assignment of new tRNA identities and a change in the genetic code.
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Affiliation(s)
- Emmanuel Noutahi
- Département d'Informatique et de Recherche opérationnelle (DIRO), Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
| | - Virginie Calderon
- Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
| | - Mathieu Blanchette
- School of Computer Science, McGill University, McConnell Engineering Bldg., Montréal, QC H3A 0E9, Canada
- McGill Centre for Bioinformatics, McGill University, Montréal, QC, Canada
| | - Nadia El-Mabrouk
- Département d'Informatique et de Recherche opérationnelle (DIRO), Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
| | - Bernd Franz Lang
- Département de Biochimie, Centre Robert Cedergren, Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
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18
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A precedented nuclear genetic code with all three termination codons reassigned as sense codons in the syndinean Amoebophrya sp. ex Karlodinium veneficum. PLoS One 2019; 14:e0212912. [PMID: 30818350 PMCID: PMC6394959 DOI: 10.1371/journal.pone.0212912] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 02/12/2019] [Indexed: 02/06/2023] Open
Abstract
Amoebophrya is part of an enigmatic, diverse, and ubiquitous marine alveolate lineage known almost entirely from anonymous environmental sequencing. Two cultured Amoebophrya strains grown on core dinoflagellate hosts were used for transcriptome sequencing. BLASTx using different genetic codes suggests that Amoebophyra sp. ex Karlodinium veneficum uses the three typical stop codons (UAA, UAG, and UGA) to encode amino acids. When UAA and UAG are translated as glutamine about half of the alignments have better BLASTx scores, and when UGA is translated as tryptophan one fifth have better scores. However, the sole stop codon appears to be UGA based on conserved genes, suggesting contingent translation of UGA. Neither host sequences, nor sequences from the second strain, Amoebophrya sp. ex Akashiwo sanguinea had similar results in BLASTx searches. A genome survey of Amoebophyra sp. ex K. veneficum showed no evidence for transcript editing aside from mitochondrial transcripts. The dynein heavy chain (DHC) gene family was surveyed and of 14 transcripts only two did not use UAA, UAG, or UGA in a coding context. Overall the transcriptome displayed strong bias for A or U in third codon positions, while the tRNA genome survey showed bias against codons ending in U, particularly for amino acids with two codons ending in either C or U. Together these clues suggest contingent translation mechanisms in Amoebophyra sp. ex K. veneficum and a phylogenetically distinct instance of genetic code modification.
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Dixit S, Henderson JC, Alfonzo JD. Multi-Substrate Specificity and the Evolutionary Basis for Interdependence in tRNA Editing and Methylation Enzymes. Front Genet 2019; 10:104. [PMID: 30838029 PMCID: PMC6382703 DOI: 10.3389/fgene.2019.00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
Among tRNA modification enzymes there is a correlation between specificity for multiple tRNA substrates and heteromultimerization. In general, enzymes that modify a conserved residue in different tRNA sequences adopt a heterodimeric structure. Presumably, such changes in the oligomeric state of enzymes, to gain multi-substrate recognition, are driven by the need to accommodate and catalyze a particular reaction in different substrates while maintaining high specificity. This review focuses on two classes of enzymes where the case for multimerization as a way to diversify molecular recognition can be made. We will highlight several new themes with tRNA methyltransferases and will also discuss recent findings with tRNA editing deaminases. These topics will be discussed in the context of several mechanisms by which heterodimerization may have been achieved during evolution and how these mechanisms might impact modifications in different systems.
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Affiliation(s)
| | | | - Juan D. Alfonzo
- Department of Microbiology, The Ohio State Biochemistry Program, The Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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20
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Recent advances in trypanosomatid research: genome organization, expression, metabolism, taxonomy and evolution. Parasitology 2018; 146:1-27. [PMID: 29898792 DOI: 10.1017/s0031182018000951] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Unicellular flagellates of the family Trypanosomatidae are obligatory parasites of invertebrates, vertebrates and plants. Dixenous species are aetiological agents of a number of diseases in humans, domestic animals and plants. Their monoxenous relatives are restricted to insects. Because of the high biological diversity, adaptability to dramatically different environmental conditions, and omnipresence, these protists have major impact on all biotic communities that still needs to be fully elucidated. In addition, as these organisms represent a highly divergent evolutionary lineage, they are strikingly different from the common 'model system' eukaryotes, such as some mammals, plants or fungi. A number of excellent reviews, published over the past decade, were dedicated to specialized topics from the areas of trypanosomatid molecular and cell biology, biochemistry, host-parasite relationships or other aspects of these fascinating organisms. However, there is a need for a more comprehensive review that summarizing recent advances in the studies of trypanosomatids in the last 30 years, a task, which we tried to accomplish with the current paper.
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21
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Wang Q, Tang G. The mitochondrial genomes of two walnut pests, Gastrolina depressa depressa and G. depressa thoracica (Coleoptera: Chrysomelidae), and phylogenetic analyses. PeerJ 2018; 6:e4919. [PMID: 29888134 PMCID: PMC5993032 DOI: 10.7717/peerj.4919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 05/16/2018] [Indexed: 11/20/2022] Open
Abstract
In this study, the mitochondrial genomes (mitogenomes) of two walnut leaf insect pests, Gastrolina depressa depressa and G. depressa thoracica, were sequenced by Sanger sequencing technology. The mitogenome of G. depressa thoracica was complete at 16,109 bp in length, while the mitogenome of G. depressa depressa (14,277 bp) was partial. The genomic analyses indicated that both mitogenomes have the typical gene content and arrangement. The formerly identified elements, 'TAGTA' between trnSer(UCN) and nad2, and 'ATGATAA' between atp8 and atp6, were more conserved than that between nad4L and nad4, which was 'ATGTTAA' in Coleoptera excluding Polyphaga. Phylogenetic analyses of the 13 protein-coding genes from 36 coleopteran species well supported a close affinity between the subfamily Chrysomelinae including G. depressa thoracica and G. depressa depressa and Galerucinae, as well as a sister relationship of ((Eumolpinae + Cryptocephalinae) + Cassidinae) within Chrysomelidae.
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Affiliation(s)
- Qiqi Wang
- Key Laboratory of State Forestry Administration on Management of Western Forest Bio-Disaster, College of Forestry, Northwest A&F University, Yangling, Shaanxi, China.,Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guanghui Tang
- Key Laboratory of State Forestry Administration on Management of Western Forest Bio-Disaster, College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
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22
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Koh CS, Sarin LP. Transfer RNA modification and infection – Implications for pathogenicity and host responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:419-432. [DOI: 10.1016/j.bbagrm.2018.01.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/04/2018] [Accepted: 01/19/2018] [Indexed: 12/19/2022]
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23
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Tuorto F, Lyko F. Genome recoding by tRNA modifications. Open Biol 2017; 6:rsob.160287. [PMID: 27974624 PMCID: PMC5204126 DOI: 10.1098/rsob.160287] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/14/2016] [Indexed: 11/12/2022] Open
Abstract
RNA modifications are emerging as an additional regulatory layer on top of the primary RNA sequence. These modifications are particularly enriched in tRNAs where they can regulate not only global protein translation, but also protein translation at the codon level. Modifications located in or in the vicinity of tRNA anticodons are highly conserved in eukaryotes and have been identified as potential regulators of mRNA decoding. Recent studies have provided novel insights into how these modifications orchestrate the speed and fidelity of translation to ensure proper protein homeostasis. This review highlights the prominent modifications in the tRNA anticodon loop: queuosine, inosine, 5-methoxycarbonylmethyl-2-thiouridine, wybutosine, threonyl-carbamoyl-adenosine and 5-methylcytosine. We discuss the functional relevance of these modifications in protein translation and their emerging role in eukaryotic genome recoding during cellular adaptation and disease.
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Affiliation(s)
- Francesca Tuorto
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
| | - Frank Lyko
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany
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24
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Editing and methylation at a single site by functionally interdependent activities. Nature 2017; 542:494-497. [PMID: 28230119 DOI: 10.1038/nature21396] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/18/2017] [Indexed: 02/02/2023]
Abstract
Nucleic acids undergo naturally occurring chemical modifications. Over 100 different modifications have been described and every position in the purine and pyrimidine bases can be modified; often the sugar is also modified. Despite recent progress, the mechanism for the biosynthesis of most modifications is not fully understood, owing, in part, to the difficulty associated with reconstituting enzyme activity in vitro. Whereas some modifications can be efficiently formed with purified components, others may require more intricate pathways. A model for modification interdependence, in which one modification is a prerequisite for another, potentially explains a major hindrance in reconstituting enzymatic activity in vitro. This model was prompted by the earlier discovery of tRNA cytosine-to-uridine editing in eukaryotes, a reaction that has not been recapitulated in vitro and the mechanism of which remains unknown. Here we show that cytosine 32 in the anticodon loop of Trypanosoma brucei tRNAThr is methylated to 3-methylcytosine (m3C) as a pre-requisite for C-to-U deamination. Formation of m3C in vitro requires the presence of both the T. brucei m3C methyltransferase TRM140 and the deaminase ADAT2/3. Once formed, m3C is deaminated to 3-methyluridine (m3U) by the same set of enzymes. ADAT2/3 is a highly mutagenic enzyme, but we also show that when co-expressed with the methyltransferase its mutagenicity is kept in check. This helps to explain how T. brucei escapes 'wholesale deamination' of its genome while harbouring both enzymes in the nucleus. This observation has implications for the control of another mutagenic deaminase, human AID, and provides a rationale for its regulation.
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Abstract
All types of nucleic acids in cells undergo naturally occurring chemical modifications, including DNA, rRNA, mRNA, snRNA, and most prominently tRNA. Over 100 different modifications have been described and every position in the purine and pyrimidine bases can be modified; often the sugar is also modified [1]. In tRNA, the function of modifications varies; some modulate global and/or local RNA structure, and others directly impact decoding and may be essential for viability. Whichever the case, the overall importance of modifications is highlighted by both their evolutionary conservation and the fact that organisms use a substantial portion of their genomes to encode modification enzymes, far exceeding what is needed for the de novo synthesis of the canonical nucleotides themselves [2]. Although some modifications occur at exactly the same nucleotide position in tRNAs from the three domains of life, many can be found at various positions in a particular tRNA and their location may vary between and within different tRNAs. With this wild array of chemical diversity and substrate specificities, one of the big challenges in the tRNA modification field has been to better understand at a molecular level the modes of substrate recognition by the different modification enzymes; in this realm RNA binding rests at the heart of the problem. This chapter will focus on several examples of modification enzymes where their mode of RNA binding is well understood; from these, we will try to draw general conclusions and highlight growing themes that may be applicable to the RNA modification field at large.
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Abstract
Apolipoprotein B mRNA Editing Catalytic Polypeptide-like 1 or APOBEC1 was discovered in 1993 as the zinc-dependent cytidine deaminase responsible for the production of an in frame stop codon in apoB mRNA through modification of cytidine at nucleotide position 6666 to uridine. At the time of this discovery there was much speculation concerning the mechanism of base modification RNA editing which has been rekindled by the discovery of multiple C to U RNA editing events in the 3′ UTRs of mRNAs and the finding that other members of the APOBEC family while able to bind RNA, have the biological function of being DNA mutating enzymes. Current research is addressing the mechanism for these nucleotide modification events that appear not to adhere to the mooring sequence-dependent model for APOBEC1 involving the assembly of a multi protein containing editosome. This review will summarize our current understanding of the structure and function of APOBEC proteins and examine how RNA binding to them may be a regulatory mechanism.
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Affiliation(s)
- Harold C Smith
- a University of Rochester, School of Medicine and Dentistry , Department of Biochemistry and Biophysics , Rochester , NY , USA
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27
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Kayal E, Bentlage B, Collins AG. Insights into the transcriptional and translational mechanisms of linear organellar chromosomes in the box jellyfish Alatina alata (Cnidaria: Medusozoa: Cubozoa). RNA Biol 2016; 13:799-809. [PMID: 27267414 DOI: 10.1080/15476286.2016.1194161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In most animals, the mitochondrial genome is characterized by its small size, organization into a single circular molecule, and a relative conservation of the number of encoded genes. In box jellyfish (Cubozoa, Cnidaria), the mitochondrial genome is organized into 8 linear mito-chromosomes harboring between one and 4 genes each, including 2 extra protein-coding genes: mt-polB and orf314. Such an organization challenges the traditional view of mitochondrial DNA (mtDNA) expression in animals. In this study, we investigate the pattern of mitochondrial gene expression in the box jellyfish Alatina alata, as well as several key nuclear-encoded molecular pathways involved in the processing of mitochondrial gene transcription. RESULTS Read coverage of DNA-seq data is relatively uniform for all 8 mito-chromosomes, suggesting that each mito-chromosome is present in equimolar proportion in the mitochondrion. Comparison of DNA and RNA-seq based assemblies indicates that mito-chromosomes are transcribed into individual transcripts in which the beginning and ending are highly conserved. Expression levels for mt-polB and orf314 are similar to those of other mitochondrial-encoded genes, which provides further evidence for them having functional roles in the mitochondrion. Survey of the transcriptome suggests recognition of the mitochondrial tRNA-Met by the cytoplasmic aminoacyl-tRNA synthetase counterpart and C-to-U editing of the cytoplasmic tRNA-Trp after import into the mitochondrion. Moreover, several mitochondrial ribosomal proteins appear to be lost. CONCLUSIONS This study represents the first survey of mitochondrial gene expression of the linear multi-chromosomal mtDNA in box jellyfish (Cubozoa). Future exploration of small RNAs and the proteome of the mitochondrion will test the hypotheses presented herein.
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Affiliation(s)
- Ehsan Kayal
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA
| | - Bastian Bentlage
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA
| | - Allen G Collins
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA.,b National Systematics Laboratory of NOAA's Fisheries Service, National Museum of Natural History , Washington , DC , USA
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28
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Faktorová D, Dobáková E, Peña-Diaz P, Lukeš J. From simple to supercomplex: mitochondrial genomes of euglenozoan protists. F1000Res 2016. [PMID: 27018240 DOI: 10.12688/f1000research.8040.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitochondria are double membrane organelles of endosymbiotic origin, best known for constituting the centre of energetics of a eukaryotic cell. They contain their own mitochondrial genome, which as a consequence of gradual reduction during evolution typically contains less than two dozens of genes. In this review, we highlight the extremely diverse architecture of mitochondrial genomes and mechanisms of gene expression between the three sister groups constituting the phylum Euglenozoa - Euglenida, Diplonemea and Kinetoplastea. The earliest diverging euglenids possess a simplified mitochondrial genome and a conventional gene expression, whereas both are highly complex in the two other groups. The expression of their mitochondrial-encoded proteins requires extensive post-transcriptional modifications guided by complex protein machineries and multiple small RNA molecules. Moreover, the least studied diplonemids, which have been recently discovered as a highly abundant component of the world ocean plankton, possess one of the most complicated mitochondrial genome organisations known to date.
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Affiliation(s)
- Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Dobáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Departments of Biochemistry and Genetics, Faculty of Natural Sciences, Comenius Universtity, Bratislava, Slovakia
| | - Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Canadian Institute for Adavanced Research, Toronto, Ontario, Canada
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29
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Faktorová D, Dobáková E, Peña-Diaz P, Lukeš J. From simple to supercomplex: mitochondrial genomes of euglenozoan protists. F1000Res 2016; 5. [PMID: 27018240 PMCID: PMC4806707 DOI: 10.12688/f1000research.8040.2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/15/2016] [Indexed: 01/06/2023] Open
Abstract
Mitochondria are double membrane organelles of endosymbiotic origin, best known for constituting the centre of energetics of a eukaryotic cell. They contain their own mitochondrial genome, which as a consequence of gradual reduction during evolution typically contains less than two dozens of genes. In this review, we highlight the extremely diverse architecture of mitochondrial genomes and mechanisms of gene expression between the three sister groups constituting the phylum Euglenozoa - Euglenida, Diplonemea and Kinetoplastea. The earliest diverging euglenids possess a simplified mitochondrial genome and a conventional gene expression, whereas both are highly complex in the two other groups. The expression of their mitochondrial-encoded proteins requires extensive post-transcriptional modifications guided by complex protein machineries and multiple small RNA molecules. Moreover, the least studied diplonemids, which have been recently discovered as a highly abundant component of the world ocean plankton, possess one of the most complicated mitochondrial genome organisations known to date.
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Affiliation(s)
- Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Dobáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Departments of Biochemistry and Genetics, Faculty of Natural Sciences, Comenius Universtity, Bratislava, Slovakia
| | - Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Canadian Institute for Adavanced Research, Toronto, Ontario, Canada
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30
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Zíková A, Hampl V, Paris Z, Týč J, Lukeš J. Aerobic mitochondria of parasitic protists: Diverse genomes and complex functions. Mol Biochem Parasitol 2016; 209:46-57. [PMID: 26906976 DOI: 10.1016/j.molbiopara.2016.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/16/2016] [Accepted: 02/17/2016] [Indexed: 02/08/2023]
Abstract
In this review the main features of the mitochondria of aerobic parasitic protists are discussed. While the best characterized organelles are by far those of kinetoplastid flagellates and Plasmodium, we also consider amoebae Naegleria and Acanthamoeba, a ciliate Ichthyophthirius and related lineages. The simplistic view of the mitochondrion as just a power house of the cell has already been abandoned in multicellular organisms and available data indicate that this also does not apply for protists. We discuss in more details the following mitochondrial features: genomes, post-transcriptional processing, translation, biogenesis of iron-sulfur complexes, heme metabolism and the electron transport chain. Substantial differences in all these core mitochondrial features between lineages are compatible with the view that aerobic protists harbor organelles that are more complex and flexible than previously appreciated.
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Affiliation(s)
- Alena Zíková
- Institute of Parasitology, Biology Centre, České Budějovice (Budweis), Czech Republic; University of South Bohemia, Faculty of Science, České Budějovice (Budweis), Czech Republic.
| | - Vladimír Hampl
- Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, České Budějovice (Budweis), Czech Republic
| | - Jiří Týč
- Institute of Parasitology, Biology Centre, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, České Budějovice (Budweis), Czech Republic; University of South Bohemia, Faculty of Science, České Budějovice (Budweis), Czech Republic; Canadian Institute for Advanced Research, Toronto, Canada.
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31
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Dobáková E, Flegontov P, Skalický T, Lukeš J. Unexpectedly Streamlined Mitochondrial Genome of the Euglenozoan Euglena gracilis. Genome Biol Evol 2015; 7:3358-67. [PMID: 26590215 PMCID: PMC4700960 DOI: 10.1093/gbe/evv229] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2015] [Indexed: 11/29/2022] Open
Abstract
In this study, we describe the mitochondrial genome of the excavate flagellate Euglena gracilis. Its gene complement is reduced as compared with the well-studied sister groups Diplonemea and Kinetoplastea. We have identified seven protein-coding genes: Three subunits of respiratory complex I (nad1, nad4, and nad5), one subunit of complex III (cob), and three subunits of complex IV (cox1, cox2, and a highly divergent cox3). Moreover, fragments of ribosomal RNA genes have also been identified. Genes encoding subunits of complex V, ribosomal proteins and tRNAs were missing, and are likely located in the nuclear genome. Although mitochondrial genomes of diplonemids and kinetoplastids possess the most complex RNA processing machineries known, including trans-splicing and editing of the uridine insertion/deletion type, respectively, our transcriptomic data suggest their total absence in E. gracilis. This finding supports a scenario in which the complex mitochondrial processing machineries of both sister groups evolved relatively late in evolution from a streamlined genome and transcriptome of their common predecessor.
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Affiliation(s)
- Eva Dobáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic Departments of Biochemistry and Genetics, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Pavel Flegontov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Tomáš Skalický
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic Canadian Institute for Advanced Research, Toronto, Ontario, Canada
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32
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Machnicka MA, Olchowik A, Grosjean H, Bujnicki JM. Distribution and frequencies of post-transcriptional modifications in tRNAs. RNA Biol 2015; 11:1619-29. [PMID: 25611331 DOI: 10.4161/15476286.2014.992273] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Functional tRNA molecules always contain a wide variety of post-transcriptionally modified nucleosides. These modifications stabilize tRNA structure, allow for proper interaction with other macromolecules and fine-tune the decoding of mRNAs during translation. Their presence in functionally important regions of tRNA is conserved in all domains of life. However, the identities of many of these modified residues depend much on the phylogeny of organisms the tRNAs are found in, attesting for domain-specific strategies of tRNA maturation. In this work we present a new tool, tRNAmodviz web server (http://genesilico.pl/trnamodviz) for easy comparative analysis and visualization of modification patterns in individual tRNAs, as well as in groups of selected tRNA sequences. We also present results of comparative analysis of tRNA sequences derived from 7 phylogenetically distinct groups of organisms: Gram-negative bacteria, Gram-positive bacteria, cytosol of eukaryotic single cell organisms, Fungi and Metazoa, cytosol of Viridiplantae, mitochondria, plastids and Euryarchaeota. These data update the study conducted 20 y ago with the tRNA sequences available at that time.
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33
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Ling J, O'Donoghue P, Söll D. Genetic code flexibility in microorganisms: novel mechanisms and impact on physiology. Nat Rev Microbiol 2015; 13:707-721. [PMID: 26411296 DOI: 10.1038/nrmicro3568] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The genetic code, initially thought to be universal and immutable, is now known to contain many variations, including biased codon usage, codon reassignment, ambiguous decoding and recoding. As a result of recent advances in the areas of genome sequencing, biochemistry, bioinformatics and structural biology, our understanding of genetic code flexibility has advanced substantially in the past decade. In this Review, we highlight the prevalence, evolution and mechanistic basis of genetic code variations in microorganisms, and we discuss how this flexibility of the genetic code affects microbial physiology.
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Affiliation(s)
- Jiqiang Ling
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada.,Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA.,Department of Chemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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34
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Hamashima K, Kanai A. Alternative genetic code for amino acids and transfer RNA revisited. Biomol Concepts 2015; 4:309-18. [PMID: 25436582 DOI: 10.1515/bmc-2013-0002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 02/20/2013] [Indexed: 11/15/2022] Open
Abstract
The genetic code is highly conserved among all organisms and its evolution is thought to be strictly limited. However, an increasing number of studies have reported non-standard codes in prokaryotic and eukaryotic genomes. Most of these deviations from the standard code are attributable to tRNA changes relating to, for example, codon/anticodon base pairing and tRNA/aminoacyl-tRNA synthetase recognition. In this review, we focus on tRNA, a key molecule in the translation of the genetic code, and summarize the most recently published information on the evolutionary divergence of the tRNAs. Surprisingly, although higher eukaryotes, such as the nematode (worm), utilize the standard genetic code, newly identified nematode-specific tRNAs (nev-tRNAs) translate nucleotides in a manner that transgresses the code. Furthermore, a variety of additional functions of tRNAs, beyond their translation of the genetic code, have emerged rapidly. We also review these intriguing new aspects of tRNA, which have potential impacts on translational control, RNA silencing, antibiotic resistance, RNA biosynthesis, and transcriptional regulation.
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35
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Kohn AB, Sanford RS, Yoshida MA, Moroz LL. Parallel Evolution and Lineage-Specific Expansion of RNA Editing in Ctenophores. Integr Comp Biol 2015; 55:1111-20. [PMID: 26089435 DOI: 10.1093/icb/icv065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
RNA editing is a process of targeted alterations of nucleotides in all types of RNA molecules (e.g., rRNA, tRNA, mRNA, and miRNA). As a result, the transcriptional output differs from its genomic DNA template. RNA editing can be defined both by biochemical mechanisms and by enzymes that perform these reactions. There are high levels of RNA editing detected in the mammalian nervous system, suggesting that nervous systems use this mechanism to increase protein diversity, because the post-transcription modifications lead to new gene products with novel functions. By re-annotating the ctenophore genomes, we found that the number of predicted RNA-editing enzymes is comparable to the numbers in mammals, but much greater than in other non-bilaterian basal metazoans. However, the overall molecular diversity of RNA-editing enzymes in ctenophores is lower, suggesting a possible "compensation" by an expansion of the ADAT1-like subfamily in this lineage. In two genera of ctenophores, Pleurobrachia and Mnemiopsis, there are high levels of expression for RNA-editing enzymes in their aboral organs, the integrative center involved in control of locomotion and geotaxis. This finding supports the hypothesis that RNA editing is correlated with the complexity of tissues and behaviors. Smaller numbers of RNA-editing enzymes in Porifera and Placozoa also correlates with the primary absence of neural and muscular systems in these lineages. In ctenophores, the expansion of the RNA-editing machinery can also provide mechanisms that support the remarkable capacity for regeneration in these animals. In summary, despite their compact genomes, a wide variety of epigenomic mechanisms employed by ctenophores and other non-bilaterian basal metazoans can provide novel insights into the evolutionary origins of biological novelties.
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Affiliation(s)
- Andrea B Kohn
- *The Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA
| | - Rachel S Sanford
- *The Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA
| | - Masa-aki Yoshida
- *The Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA; Research fellow of the Japan Society for the Promotion of Science; Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Leonid L Moroz
- *The Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St Augustine, FL 32080, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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36
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Salinas-Giegé T, Giegé R, Giegé P. tRNA biology in mitochondria. Int J Mol Sci 2015; 16:4518-59. [PMID: 25734984 PMCID: PMC4394434 DOI: 10.3390/ijms16034518] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/23/2015] [Accepted: 01/29/2015] [Indexed: 01/23/2023] Open
Abstract
Mitochondria are the powerhouses of eukaryotic cells. They are considered as semi-autonomous because they have retained genomes inherited from their prokaryotic ancestor and host fully functional gene expression machineries. These organelles have attracted considerable attention because they combine bacterial-like traits with novel features that evolved in the host cell. Among them, mitochondria use many specific pathways to obtain complete and functional sets of tRNAs as required for translation. In some instances, tRNA genes have been partially or entirely transferred to the nucleus and mitochondria require precise import systems to attain their pool of tRNAs. Still, tRNA genes have also often been maintained in mitochondria. Their genetic arrangement is more diverse than previously envisaged. The expression and maturation of mitochondrial tRNAs often use specific enzymes that evolved during eukaryote history. For instance many mitochondria use a eukaryote-specific RNase P enzyme devoid of RNA. The structure itself of mitochondrial encoded tRNAs is also very diverse, as e.g., in Metazoan, where tRNAs often show non canonical or truncated structures. As a result, the translational machinery in mitochondria evolved adapted strategies to accommodate the peculiarities of these tRNAs, in particular simplified identity rules for their aminoacylation. Here, we review the specific features of tRNA biology in mitochondria from model species representing the major eukaryotic groups, with an emphasis on recent research on tRNA import, maturation and aminoacylation.
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Affiliation(s)
- Thalia Salinas-Giegé
- Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg Cedex, France.
| | - Richard Giegé
- Institut de Biologie Moléculaire et Cellulaire, CNRS and Université de Strasbourg, 15 rue René Descartes, F-67084 Strasbourg Cedex, France.
| | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg Cedex, France.
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37
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Verner Z, Basu S, Benz C, Dixit S, Dobáková E, Faktorová D, Hashimi H, Horáková E, Huang Z, Paris Z, Peña-Diaz P, Ridlon L, Týč J, Wildridge D, Zíková A, Lukeš J. Malleable mitochondrion of Trypanosoma brucei. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:73-151. [PMID: 25708462 DOI: 10.1016/bs.ircmb.2014.11.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The importance of mitochondria for a typical aerobic eukaryotic cell is undeniable, as the list of necessary mitochondrial processes is steadily growing. Here, we summarize the current knowledge of mitochondrial biology of an early-branching parasitic protist, Trypanosoma brucei, a causative agent of serious human and cattle diseases. We present a comprehensive survey of its mitochondrial pathways including kinetoplast DNA replication and maintenance, gene expression, protein and metabolite import, major metabolic pathways, Fe-S cluster synthesis, ion homeostasis, organellar dynamics, and other processes. As we describe in this chapter, the single mitochondrion of T. brucei is everything but simple and as such rivals mitochondria of multicellular organisms.
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Affiliation(s)
- Zdeněk Verner
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Present address: Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia; Present address: Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Somsuvro Basu
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Present address: Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Germany
| | - Corinna Benz
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Sameer Dixit
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Dobáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Present address: Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Hassan Hashimi
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Zhenqiu Huang
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Lucie Ridlon
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic; Present address: Salk Institute, La Jolla, San Diego, USA
| | - Jiří Týč
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - David Wildridge
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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Betat H, Long Y, Jackman JE, Mörl M. From end to end: tRNA editing at 5'- and 3'-terminal positions. Int J Mol Sci 2014; 15:23975-98. [PMID: 25535083 PMCID: PMC4284800 DOI: 10.3390/ijms151223975] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 12/10/2014] [Accepted: 12/16/2014] [Indexed: 01/29/2023] Open
Abstract
During maturation, tRNA molecules undergo a series of individual processing steps, ranging from exo- and endonucleolytic trimming reactions at their 5'- and 3'-ends, specific base modifications and intron removal to the addition of the conserved 3'-terminal CCA sequence. Especially in mitochondria, this plethora of processing steps is completed by various editing events, where base identities at internal positions are changed and/or nucleotides at 5'- and 3'-ends are replaced or incorporated. In this review, we will focus predominantly on the latter reactions, where a growing number of cases indicate that these editing events represent a rather frequent and widespread phenomenon. While the mechanistic basis for 5'- and 3'-end editing differs dramatically, both reactions represent an absolute requirement for generating a functional tRNA. Current in vivo and in vitro model systems support a scenario in which these highly specific maturation reactions might have evolved out of ancient promiscuous RNA polymerization or quality control systems.
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Affiliation(s)
- Heike Betat
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany.
| | - Yicheng Long
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, the Ohio State University, Columbus, OH 43210, USA.
| | - Jane E Jackman
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, the Ohio State University, Columbus, OH 43210, USA.
| | - Mario Mörl
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany.
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39
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Liu M, Zhang Z, Peng Z. The mitochondrial genome of the water spiderArgyroneta aquatica(Araneae: Cybaeidae). ZOOL SCR 2014. [DOI: 10.1111/zsc.12090] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Mingxin Liu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education); Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education); School of Life Science; Southwest University; Chongqing 400715 China
| | - Zhisheng Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education); Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education); School of Life Science; Southwest University; Chongqing 400715 China
| | - Zuogang Peng
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education); Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education); School of Life Science; Southwest University; Chongqing 400715 China
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40
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Zhou W, Karcher D, Bock R. Identification of enzymes for adenosine-to-inosine editing and discovery of cytidine-to-uridine editing in nucleus-encoded transfer RNAs of Arabidopsis. PLANT PHYSIOLOGY 2014; 166:1985-97. [PMID: 25315605 PMCID: PMC4256874 DOI: 10.1104/pp.114.250498] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 10/11/2014] [Indexed: 05/18/2023]
Abstract
In all organisms, transfer RNAs (tRNAs) contain numerous modified nucleotides. For many base modifications in tRNAs, the functional significance is not well understood, and the enzymes performing the modification reactions are unknown. Here, we have studied members of a family of putative nucleotide deaminases in the model plant Arabidopsis (Arabidopsis thaliana). We show that two Arabidopsis genes encoding homologs of yeast (Saccharomyces cerevisiae) tRNA adenosine deaminases catalyze adenosine-to-inosine editing in position 34 of several cytosolic tRNA species. The encoded proteins (AtTAD2 and AtTAD3, for tRNA-specific adenosine deaminase) localize to the nucleus and interact with each other in planta in bimolecular fluorescence complementation and coimmunoprecipitation assays. Both AtTAD2 and AtTAD3 are encoded by essential genes whose knockout is lethal and leads to arrested embryo development at the globular stage. Knockdown mutants for AtTAD2 and AtTAD3 display reduced growth and inefficient editing from adenosine to inosine in six nucleus-encoded tRNA species. Moreover, upon comparison of DNA and complementary DNA sequences, we discovered cytidine-to-uridine RNA editing in position 32 of two nucleus-encoded serine tRNAs, tRNA-serine(AGA) and tRNA-serine(GCT). This adds a unique type of RNA editing to the modifications occurring in nuclear genome-encoded RNAs in plants.
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Affiliation(s)
- Wenbin Zhou
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
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41
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Abad MG, Long Y, Kinchen RD, Schindel ET, Gray MW, Jackman JE. Mitochondrial tRNA 5'-editing in Dictyostelium discoideum and Polysphondylium pallidum. J Biol Chem 2014; 289:15155-65. [PMID: 24737330 DOI: 10.1074/jbc.m114.561514] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Mitochondrial tRNA (mt-tRNA) 5'-editing was first described more than 20 years ago; however, the first candidates for 5'-editing enzymes were only recently identified in a eukaryotic microbe (protist), the slime mold Dictyostelium discoideum. In this organism, eight of 18 mt-tRNAs are predicted to be edited based on the presence of genomically encoded mismatched nucleotides in their aminoacyl-acceptor stem sequences. Here, we demonstrate that mt-tRNA 5'-editing occurs at all predicted sites in D. discoideum as evidenced by changes in the sequences of isolated mt-tRNAs compared with the expected sequences encoded by the mitochondrial genome. We also identify two previously unpredicted editing events in which G-U base pairs are edited in the absence of any other genomically encoded mismatches. A comparison of 5'-editing in D. discoideum with 5'-editing in another slime mold, Polysphondylium pallidum, suggests organism-specific idiosyncrasies in the treatment of U-G/G-U pairs. In vitro activities of putative D. discoideum editing enzymes are consistent with the observed editing reactions and suggest an overall lack of tRNA substrate specificity exhibited by the repair component of the editing enzyme. Although the presence of terminal mismatches in mt-tRNA sequences is highly predictive of the occurrence of mt-tRNA 5'-editing, the variability in treatment of U-G/G-U base pairs observed here indicates that direct experimental evidence of 5'-editing must be obtained to understand the complete spectrum of mt-tRNA editing events in any species.
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Affiliation(s)
- Maria G Abad
- From the Department of Chemistry and Biochemistry, Center for RNA Biology and
| | - Yicheng Long
- From the Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210 and
| | - R Dimitri Kinchen
- From the Department of Chemistry and Biochemistry, Center for RNA Biology and
| | - Elinor T Schindel
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Michael W Gray
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jane E Jackman
- From the Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210 and
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42
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43
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Pham JS, Dawson KL, Jackson KE, Lim EE, Pasaje CFA, Turner KEC, Ralph SA. Aminoacyl-tRNA synthetases as drug targets in eukaryotic parasites. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 4:1-13. [PMID: 24596663 PMCID: PMC3940080 DOI: 10.1016/j.ijpddr.2013.10.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 01/02/2023]
Abstract
Aminoacyl-tRNA synthetases are essential and many aaRS inhibitors kill parasites. We examine compound inhibitors tested experimentally against parasite aaRSs. Successful inhibitors were discovered by both phenotype and target-based approaches. Selectivity and resistance are ongoing challenges for development of parasite drugs.
Aminoacyl-tRNA synthetases are central enzymes in protein translation, providing the charged tRNAs needed for appropriate construction of peptide chains. These enzymes have long been pursued as drug targets in bacteria and fungi, but the past decade has seen considerable research on aminoacyl-tRNA synthetases in eukaryotic parasites. Existing inhibitors of bacterial tRNA synthetases have been adapted for parasite use, novel inhibitors have been developed against parasite enzymes, and tRNA synthetases have been identified as the targets for compounds in use or development as antiparasitic drugs. Crystal structures have now been solved for many parasite tRNA synthetases, and opportunities for selective inhibition are becoming apparent. For different biological reasons, tRNA synthetases appear to be promising drug targets against parasites as diverse as Plasmodium (causative agent of malaria), Brugia (causative agent of lymphatic filariasis), and Trypanosoma (causative agents of Chagas disease and human African trypanosomiasis). Here we review recent developments in drug discovery and target characterisation for parasite aminoacyl-tRNA synthetases.
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Affiliation(s)
- James S Pham
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Karen L Dawson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Katherine E Jackson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Erin E Lim
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Charisse Flerida A Pasaje
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Kelsey E C Turner
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
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44
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Rubio MAT, Paris Z, Gaston KW, Fleming IMC, Sample P, Trotta CR, Alfonzo JD. Unusual noncanonical intron editing is important for tRNA splicing in Trypanosoma brucei. Mol Cell 2013; 52:184-92. [PMID: 24095278 DOI: 10.1016/j.molcel.2013.08.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/16/2013] [Accepted: 08/20/2013] [Indexed: 02/01/2023]
Abstract
In cells, tRNAs are synthesized as precursor molecules bearing extra sequences at their 5' and 3' ends. Some tRNAs also contain introns, which, in archaea and eukaryotes, are cleaved by an evolutionarily conserved endonuclease complex that generates fully functional mature tRNAs. In addition, tRNAs undergo numerous posttranscriptional nucleotide chemical modifications. In Trypanosoma brucei, the single intron-containing tRNA (tRNA(Tyr)GUA) is responsible for decoding all tyrosine codons; therefore, intron removal is essential for viability. Using molecular and biochemical approaches, we show the presence of several noncanonical editing events, within the intron of pre-tRNA(Tyr)GUA, involving guanosine-to-adenosine transitions (G to A) and an adenosine-to-uridine transversion (A to U). The RNA editing described here is required for proper processing of the intron, establishing the functional significance of noncanonical editing with implications for tRNA processing in the deeply divergent kinetoplastid lineage and eukaryotes in general.
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Affiliation(s)
- Mary Anne T Rubio
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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45
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Cristodero M, Mani J, Oeljeklaus S, Aeberhard L, Hashimi H, Ramrath DJF, Lukeš J, Warscheid B, Schneider A. Mitochondrial translation factors of Trypanosoma brucei: elongation factor-Tu has a unique subdomain that is essential for its function. Mol Microbiol 2013; 90:744-55. [PMID: 24033548 DOI: 10.1111/mmi.12397] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2013] [Indexed: 11/28/2022]
Abstract
Mitochondrial translation in the parasitic protozoan Trypanosoma brucei relies on imported eukaryotic-type tRNAs as well as on bacterial-type ribosomes that have the shortest known rRNAs. Here we have identified the mitochondrial translation elongation factors EF-Tu, EF-Ts, EF-G1 and release factor RF1 of trypanosomatids and show that their ablation impairs growth and oxidative phosphorylation. In vivo labelling experiments and a SILAC-based analysis of the global proteomic changes induced by EF-Tu RNAi directly link EF-Tu to mitochondrial translation. Moreover, EF-Tu RNAi reveals downregulation of many nuclear encoded subunits of cytochrome oxidase as well as of components of the bc1-complex, whereas most cytosolic ribosomal proteins were upregulated. Interestingly, T. brucei EF-Tu has a 30-amino-acid-long, highly charged subdomain, which is unique to trypanosomatids. A combination of RNAi and complementation experiments shows that this subdomain is essential for EF-Tu function, but that it can be replaced by a similar sequence found in eukaryotic EF-1a, the cytosolic counterpart of EF-Tu. A recent cryo-electron microscopy study revealed that trypanosomatid mitochondrial ribosomes have a unique intersubunit space that likely harbours the EF-Tu binding site. These findings suggest that the trypanosomatid-specific EF-Tu subdomain serves as an adaption for binding to these unusual mitochondrial ribosomes.
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Affiliation(s)
- Marina Cristodero
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland
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46
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Paris Z, Horáková E, Rubio MAT, Sample P, Fleming IM, Armocida S, Lukeš J, Alfonzo JD. The T. brucei TRM5 methyltransferase plays an essential role in mitochondrial protein synthesis and function. RNA (NEW YORK, N.Y.) 2013; 19:649-658. [PMID: 23520175 PMCID: PMC3677280 DOI: 10.1261/rna.036665.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/01/2013] [Indexed: 06/01/2023]
Abstract
All tRNAs undergo post-transcriptional chemical modifications as part of their natural maturation pathway. Some modifications, especially those in the anticodon loop, play important functions in translational efficiency and fidelity. Among these, 1-methylguanosine, at position 37 (m(1)G37) of the anticodon loop in several tRNAs, is evolutionarily conserved and participates in translational reading frame maintenance. In eukaryotes, the tRNA methyltransferase TRM5 is responsible for m(1)G formation in nucleus-encoded as well as mitochondria-encoded tRNAs, reflecting the universal importance of this modification for protein synthesis. However, it is not clear what role, if any, mitochondrial TRM5 serves in organisms that do not encode tRNAs in their mitochondrial genomes. These organisms may easily satisfy the m(1)G37 requirement through their robust mitochondrial tRNA import mechanisms. We have explored this possibility in the parasitic protist Trypanosoma brucei and show that down-regulation of TRM5 by RNAi leads to the expected disappearance of m(1)G37, but with surprisingly little effect on cytoplasmic translation. On the contrary, lack of TRM5 causes a marked growth phenotype and a significant decrease in mitochondrial functions, including protein synthesis. These results suggest mitochondrial TRM5 may be needed to mature unmethylated tRNAs that reach the mitochondria and that could pose a problem for translational fidelity. This study also reveals an unexpected lack of import specificity between some fully matured and potentially defective tRNA species.
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Affiliation(s)
- Zdeněk Paris
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Eva Horáková
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, and Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Mary Anne T. Rubio
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Paul Sample
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ian M.C. Fleming
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Stephanie Armocida
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, and Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Juan D. Alfonzo
- Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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47
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Zhou W, Karcher D, Bock R. Importance of adenosine-to-inosine editing adjacent to the anticodon in an Arabidopsis alanine tRNA under environmental stress. Nucleic Acids Res 2013; 41:3362-72. [PMID: 23355609 PMCID: PMC3597679 DOI: 10.1093/nar/gkt013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In all organisms, transfer RNAs (tRNAs) undergo extensive post-transcriptional modifications. Although base modifications in the anticodon are known to alter decoding specificity or improve decoding accuracy, much less is known about the functional relevance of modifications in other positions of tRNAs. Here, we report the identification of an A-to-I tRNA editing enzyme that modifies the tRNA-Ala(AGC) in the model plant Arabidopsis thaliana. The enzyme is homologous to Tad1p, a yeast tRNA-specific adenosine deaminase, and it selectively deaminates the adenosine in the position 3'-adjacent to the anticodon (A37) to inosine. We show that the AtTAD1 protein is exclusively localized in the nucleus. The tad1 loss-of-function mutants isolated in Arabidopsis show normal accumulation of the tRNA-Ala(AGC), suggesting that the loss of the I37 modification does not affect tRNA stability. The tad1 knockout mutants display no discernible phenotype under standard growth conditions, but produce less biomass under environmental stress conditions. Our results provide the first evidence in support of a physiological relevance of the A37-to-I modification in eukaryotes.
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Affiliation(s)
| | | | - Ralph Bock
- *To whom correspondence should be addressed. Tel: +49 3315 67 8700; Fax: +49 3315 67 8701;
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48
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El Yacoubi B, Bailly M, de Crécy-Lagard V. Biosynthesis and Function of Posttranscriptional Modifications of Transfer RNAs. Annu Rev Genet 2012; 46:69-95. [DOI: 10.1146/annurev-genet-110711-155641] [Citation(s) in RCA: 380] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Basma El Yacoubi
- Department of Microbiology and Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700;
| | - Marc Bailly
- Department of Microbiology and Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700;
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700;
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49
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Lavrov DV, Pett W, Voigt O, Wörheide G, Forget L, Lang BF, Kayal E. Mitochondrial DNA of Clathrina clathrus (Calcarea, Calcinea): six linear chromosomes, fragmented rRNAs, tRNA editing, and a novel genetic code. Mol Biol Evol 2012; 30:865-80. [PMID: 23223758 DOI: 10.1093/molbev/mss274] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sponges (phylum Porifera) are a large and ancient group of morphologically simple but ecologically important aquatic animals. Although their body plan and lifestyle are relatively uniform, sponges show extensive molecular and genetic diversity. In particular, mitochondrial genomes from three of the four previously studied classes of Porifera (Demospongiae, Hexactinellida, and Homoscleromorpha) have distinct gene contents, genome organizations, and evolutionary rates. Here, we report the mitochondrial genome of Clathrina clathrus (Calcinea, Clathrinidae), a representative of the fourth poriferan class, the Calcarea, which proves to be the most unusual. Clathrina clathrus mitochondrial DNA (mtDNA) consists of six linear chromosomes 7.6-9.4 kb in size and encodes at least 37 genes: 13 protein codings, 2 ribosomal RNAs (rRNAs), and 24 transfer RNAs (tRNAs). Protein genes include atp9, which has now been found in all major sponge lineages, but no atp8. Our analyses further reveal the presence of a novel genetic code that involves unique reassignments of the UAG codons from termination to tyrosine and of the CGN codons from arginine to glycine. Clathrina clathrus mitochondrial rRNAs are encoded in three (srRNA) and ≥6 (lrRNA) fragments distributed out of order and on several chromosomes. The encoded tRNAs contain multiple mismatches in the aminoacyl acceptor stems that are repaired posttranscriptionally by 3'-end RNA editing. Although our analysis does not resolve the phylogenetic position of calcareous sponges, likely due to their high rates of mitochondrial sequence evolution, it confirms mtDNA as a promising marker for population studies in this group. The combination of unusual mitochondrial features in C. clathrus redefines the extremes of mtDNA evolution in animals and further argues against the idea of a "typical animal mtDNA."
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Affiliation(s)
- Dennis V Lavrov
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Iowa, USA.
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50
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Jackman JE, Alfonzo JD. Transfer RNA modifications: nature's combinatorial chemistry playground. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:35-48. [PMID: 23139145 DOI: 10.1002/wrna.1144] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Following synthesis, tRNAs are peppered by numerous chemical modifications which may differentially affect a tRNA's structure and function. Although modifications affecting the business ends of a tRNA are predictably important for cell viability, a majority of modifications play more subtle structural roles that can affect tRNA stability and folding. The current trend is that modifications act in concert and it is in the context of the specific sequence of a given tRNA that they impart their differing effects. Recent developments in the modification field have highlighted the diversity of modifications in tRNA. From these, the combinatorial nature of modifications in explaining previously described phenotypes derived from their absence has emerged as a growing theme.
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Affiliation(s)
- Jane E Jackman
- The Ohio State Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
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