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Muneretto G, Plazzi F, Passamonti M. Mitochondrion-to-nucleus communication mediated by RNA export: a survey of potential mechanisms and players across eukaryotes. Biol Lett 2024; 20:20240147. [PMID: 38982851 PMCID: PMC11283861 DOI: 10.1098/rsbl.2024.0147] [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: 03/20/2024] [Revised: 05/16/2024] [Accepted: 06/06/2024] [Indexed: 07/11/2024] Open
Abstract
The nucleus interacts with the other organelles to perform essential functions of the eukaryotic cell. Mitochondria have their own genome and communicate back to the nucleus in what is known as mitochondrial retrograde response. Information is transferred to the nucleus in many ways, leading to wide-ranging changes in nuclear gene expression and culminating with changes in metabolic, regulatory or stress-related pathways. RNAs are emerging molecules involved in this signalling. RNAs encode precise information and are involved in highly target-specific signalling, through a wide range of processes known as RNA interference. RNA-mediated mitochondrial retrograde response requires these molecules to exit the mitochondrion, a process that is still mostly unknown. We suggest that the proteins/complexes translocases of the inner membrane, polynucleotide phosphorylase, mitochondrial permeability transition pore, and the subunits of oxidative phosphorylation complexes may be responsible for RNA export.
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Affiliation(s)
- Giorgio Muneretto
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Federico Plazzi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Marco Passamonti
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
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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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Gao Y, Guo L, Wang F, Wang Y, Li P, Zhang D. Development of mitochondrial gene-editing strategies and their potential applications in mitochondrial hereditary diseases: a review. Cytotherapy 2024; 26:11-24. [PMID: 37930294 DOI: 10.1016/j.jcyt.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/07/2023]
Abstract
Mitochondrial DNA (mtDNA) is a critical genome contained within the mitochondria of eukaryotic cells, with many copies present in each mitochondrion. Mutations in mtDNA often are inherited and can lead to severe health problems, including various inherited diseases and premature aging. The lack of efficient repair mechanisms and the susceptibility of mtDNA to damage exacerbate the threat to human health. Heteroplasmy, the presence of different mtDNA genotypes within a single cell, increases the complexity of these diseases and requires an effective editing method for correction. Recently, gene-editing techniques, including programmable nucleases such as restriction endonuclease, zinc finger nuclease, transcription activator-like effector nuclease, clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated 9 and base editors, have provided new tools for editing mtDNA in mammalian cells. Base editors are particularly promising because of their high efficiency and precision in correcting mtDNA mutations. In this review, we discuss the application of these techniques in mitochondrial gene editing and their limitations. We also explore the potential of base editors for mtDNA modification and discuss the opportunities and challenges associated with their application in mitochondrial gene editing. In conclusion, this review highlights the advancements, limitations and opportunities in current mitochondrial gene-editing technologies and approaches. Our insights aim to stimulate the development of new editing strategies that can ultimately alleviate the adverse effects of mitochondrial hereditary diseases.
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Affiliation(s)
- Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Linlin Guo
- The Affiliated Cardiovascular Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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4
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Hajikarimlou M, Hooshyar M, Sunba N, Nazemof N, Moutaoufik MT, Phanse S, Said KB, Babu M, Holcik M, Samanfar B, Smith M, Golshani A. A Correlation between 3'-UTR of OXA1 Gene and Yeast Mitochondrial Translation. J Fungi (Basel) 2023; 9:jof9040445. [PMID: 37108900 PMCID: PMC10143089 DOI: 10.3390/jof9040445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/27/2023] [Accepted: 04/01/2023] [Indexed: 04/29/2023] Open
Abstract
Mitochondria possess their own DNA (mtDNA) and are capable of carrying out their transcription and translation. Although protein synthesis can take place in mitochondria, the majority of the proteins in mitochondria have nuclear origin. 3' and 5' untranslated regions of mRNAs (3'-UTR and 5'-UTR, respectively) are thought to play key roles in directing and regulating the activity of mitochondria mRNAs. Here we investigate the association between the presence of 3'-UTR from OXA1 gene on a prokaryotic reporter mRNA and mitochondrial translation in yeast. OXA1 is a nuclear gene that codes for mitochondrial inner membrane insertion protein and its 3'-UTR is shown to direct its mRNA toward mitochondria. It is not clear, however, if this mRNA may also be translated by mitochondria. In the current study, using a β-galactosidase reporter gene, we provide genetic evidence for a correlation between the presence of 3'-UTR of OXA1 on an mRNA and mitochondrial translation in yeast.
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Affiliation(s)
- Maryam Hajikarimlou
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Mohsen Hooshyar
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Noor Sunba
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Nazila Nazemof
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Mohamed Taha Moutaoufik
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Sadhena Phanse
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Kamaledin B Said
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
- Department of Pathology and Microbiology, College of Medicine, University of Hail, Hail P.O. Box 2240, Saudi Arabia
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Martin Holcik
- Department of Health Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Bahram Samanfar
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre (ORDC), Ottawa, ON K2H 8S2, Canada
| | - Myron Smith
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Ashkan Golshani
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
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5
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Duroux-Richard I, Apparailly F, Khoury M. Mitochondrial MicroRNAs Contribute to Macrophage Immune Functions Including Differentiation, Polarization, and Activation. Front Physiol 2021; 12:738140. [PMID: 34803730 PMCID: PMC8595120 DOI: 10.3389/fphys.2021.738140] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/22/2021] [Indexed: 12/22/2022] Open
Abstract
A subset of microRNA (miRNA) has been shown to play an important role in mitochondrial (mt) functions and are named MitomiR. They are present within or associated with mitochondria. Most of the mitochondrial miRNAs originate from the nucleus, while a very limited number is encoded by mtDNA. Moreover, the miRNA machinery including the Dicer and Argonaute has also been detected within mitochondria. Recent, literature has established a close relationship between miRNAs and inflammation. Indeed, specific miRNA signatures are associated with macrophage differentiation, polarization and functions. Nevertheless, the regulation of macrophage inflammatory pathways governed specifically by MitomiR and their implication in immune-mediated inflammatory disorders remain poorly studied. Here, we propose a hypothesis in which MitomiR play a key role in triggering macrophage differentiation and modulating their downstream activation and immune functions. We sustain this proposition by bioinformatic data obtained from either the human monocytic THP1 cell line or the purified mitochondrial fraction of PMA-induced human macrophages. Interestingly, 22% of the 754 assayed miRNAs were detected in the mitochondrial fraction and are either exclusively or highly enriched cellular miRNA. Furthermore, the in silico analysis performed in this study, identified a specific MitomiR signature associated with macrophage differentiation that was correlated with gene targets within the mitochondria genome or with mitochondrial pathways. Overall, our hypothesis and data suggest a previously unrecognized link between MitomiR and macrophage function and fate. We also suggest that the MitomiR-dependent control could be further enhanced through the transfer of mitochondria from donor to target cells, as a new strategy for MitomiR delivery.
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Affiliation(s)
| | - Florence Apparailly
- IRMB, INSERM, Université de Montpellier, CHU Montpellier, Montpellier, France.,Clinical Department for Osteoarticular Diseases, University Hospital of Montpellier, Montpellier, France
| | - Maroun Khoury
- Laboratory of Nano-Regenerative Medicine, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.,Cells for Cells and REGENERO, The Chilean Consortium for Regenerative Medicine, Santiago, Chile.,IMPACT, Center of Interventional Medicine for Precision and Advanced Cellular Therapy, Santiago, Chile
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6
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Purohit PK, Saini N. Mitochondrial microRNA (MitomiRs) in cancer and complex mitochondrial diseases: current status and future perspectives. Cell Mol Life Sci 2021; 78:1405-1421. [PMID: 33084945 PMCID: PMC11072739 DOI: 10.1007/s00018-020-03670-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 09/13/2020] [Accepted: 10/05/2020] [Indexed: 02/08/2023]
Abstract
Mitochondria are not only important for cellular bioenergetics but also lie at the heart of critical metabolic pathways. They can rapidly adjust themselves in response to changing conditions and the metabolic needs of the cell. Mitochondrial involvement as well as its dysfunction has been found to be associated with variety of pathological processes and diseases. mitomiRs are class of miRNA(s) that regulate mitochondrial gene expression and function. This review sheds light on the role of mitomiRs in regulating different biological processes-mitochondrial dynamics, oxidative stress, cell metabolism, chemoresistance, apoptosis,and their relevance in metabolic diseases, neurodegenerative disorders, and cancer. Insilico analysis of predicted targets of mitomiRs targeting energy metabolism identified several significantly altered pathways (needs in vivo validations) that may provide a new therapeutic approach for the treatment of human diseases. Last part of the review discusses about the clinical aspects of miRNA(s) and mitomiRs in Medicine.
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Affiliation(s)
- Paresh Kumar Purohit
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research, (AcSIR), Ghaziabad, 201 002, India
| | - Neeru Saini
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.
- Academy of Scientific and Innovative Research, (AcSIR), Ghaziabad, 201 002, India.
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7
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Dong Z, Pu L, Cui H. Mitoepigenetics and Its Emerging Roles in Cancer. Front Cell Dev Biol 2020; 8:4. [PMID: 32039210 PMCID: PMC6989428 DOI: 10.3389/fcell.2020.00004] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
In human beings, there is a ∼16,569 bp circular mitochondrial DNA (mtDNA) encoding 22 tRNAs, 12S and 16S rRNAs, 13 polypeptides that constitute the central core of ETC/OxPhos complexes, and some non-coding RNAs. Recently, mtDNA has been shown to have some covalent modifications such as methylation or hydroxylmethylation, which play pivotal epigenetic roles in mtDNA replication and transcription. Post-translational modifications of proteins in mitochondrial nucleoids such as mitochondrial transcription factor A (TFAM) also emerge as essential epigenetic modulations in mtDNA replication and transcription. Post-transcriptional modifications of mitochondrial RNAs (mtRNAs) including mt-rRNAs, mt-tRNAs and mt-mRNAs are important epigenetic modulations. Besides, mtDNA or nuclear DNA (n-DNA)-derived non-coding RNAs also play important roles in the regulation of translation and function of mitochondrial genes. These evidences introduce a novel concept of mitoepigenetics that refers to the study of modulations in the mitochondria that alter heritable phenotype in mitochondria itself without changing the mtDNA sequence. Since mitochondrial dysfunction contributes to carcinogenesis and tumor development, mitoepigenetics is also essential for cancer. Understanding the mode of actions of mitoepigenetics in cancers may shade light on the clinical diagnosis and prevention of these diseases. In this review, we summarize the present study about modifications in mtDNA, mtRNA and nucleoids and modulations of mtDNA/nDNA-derived non-coding RNAs that affect mtDNA translation/function, and overview recent studies of mitoepigenetic alterations in cancer.
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Affiliation(s)
- Zhen Dong
- State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, China.,Cancer Center, Medical Research Institute, Southwest University, Chongqing, China.,Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing, China.,Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, Southwest University, Chongqing, China
| | - Longjun Pu
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, China.,Cancer Center, Medical Research Institute, Southwest University, Chongqing, China.,Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing, China.,Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, Southwest University, Chongqing, China
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8
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Ayyub SA, Varshney U. Translation initiation in mammalian mitochondria- a prokaryotic perspective. RNA Biol 2019; 17:165-175. [PMID: 31696767 DOI: 10.1080/15476286.2019.1690099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
ATP is generated in mitochondria of eukaryotic cells by oxidative phosphorylation (OXPHOS). The OXPHOS complex, which is crucial for cellular metabolism, comprises of both nuclear and mitochondrially encoded subunits. Also, the occurrence of several pathologies because of mutations in the mitochondrial translation apparatus indicates the importance of mitochondrial translation and its regulation. The mitochondrial translation apparatus is similar to its prokaryotic counterpart due to a common origin of evolution. However, mitochondrial translation has diverged from prokaryotic translation in many ways by reductive evolution. In this review, we focus on mammalian mitochondrial translation initiation, a highly regulated step of translation, and present a comparison with prokaryotic translation.
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Affiliation(s)
- Shreya Ahana Ayyub
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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9
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Gammage PA, Moraes CT, Minczuk M. Mitochondrial Genome Engineering: The Revolution May Not Be CRISPR-Ized. Trends Genet 2018; 34:101-110. [PMID: 29179920 PMCID: PMC5783712 DOI: 10.1016/j.tig.2017.11.001] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/28/2017] [Accepted: 11/02/2017] [Indexed: 12/17/2022]
Abstract
In recent years mitochondrial DNA (mtDNA) has transitioned to greater prominence across diverse areas of biology and medicine. The recognition of mitochondria as a major biochemical hub, contributions of mitochondrial dysfunction to various diseases, and several high-profile attempts to prevent hereditary mtDNA disease through mitochondrial replacement therapy have roused interest in the organellar genome. Subsequently, attempts to manipulate mtDNA have been galvanized, although with few robust advances and much controversy. Re-engineered protein-only nucleases such as mtZFN and mitoTALEN function effectively in mammalian mitochondria, although efficient delivery of nucleic acids into the organelle remains elusive. Such an achievement, in concert with a mitochondria-adapted CRISPR/Cas9 platform, could prompt a revolution in mitochondrial genome engineering and biological understanding. However, the existence of an endogenous mechanism for nucleic acid import into mammalian mitochondria, a prerequisite for mitochondrial CRISPR/Cas9 gene editing, remains controversial.
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Affiliation(s)
- Payam A Gammage
- Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - Carlos T Moraes
- Miller School of Medicine, University of Miami, Miami, FL, USA.
| | - Michal Minczuk
- Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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10
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Revisiting trends on mitochondrial mega-channels for the import of proteins and nucleic acids. J Bioenerg Biomembr 2016; 49:75-99. [DOI: 10.1007/s10863-016-9662-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/25/2016] [Indexed: 12/14/2022]
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11
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Abstract
Intracellular trafficking of viruses and proteins commonly occurs via the early endosome in a process involving Rab5. The RNA Import Complex (RIC)-RNA complex is taken up by mammalian cells and targeted to mitochondria. Through RNA interference, it was shown that mito-targeting of the ribonucleoprotein (RNP) was dependent on caveolin 1 (Cav1), dynamin 2, Filamin A and NSF. Although a minor fraction of the RNP was transported to endosomes in a Rab5-dependent manner, mito-targeting was independent of Rab5 or other endosomal proteins, suggesting that endosomal uptake and mito-targeting occur independently. Sequential immunoprecipitation of the cytosolic vesicles showed the sorting of the RNP away from Cav1 in a process that was independent of the endosomal effector EEA1 but sensitive to nocodazole. However, the RNP was in two types of vesicle with or without Cav1, with membrane-bound, asymmetrically orientated RIC and entrapped RNA, but no endosomal components, suggesting vesicular sorting rather than escape of free RNP from endosomes. In vitro, RNP was directly transferred from the Type 2 vesicles to mitochondria. Live-cell imaging captured spherical Cav1− RNP vesicles emerging from the fission of large Cav+ particles. Thus, RNP appears to traffic by a different route than the classical Rab5-dependent pathway of viral transport.
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Affiliation(s)
- Joyita Mukherjee
- Genetic Engineering Laboratory, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Calcutta 700032, India Present address: Penn Institute for Regenerative Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Biraj Mahato
- Present address: Penn Institute for Regenerative Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Samit Adhya
- Genetic Engineering Laboratory, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Calcutta 700032, India Present address: Penn Institute for Regenerative Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA.
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12
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Koley S, Adhya S. A voltage-gated pore for translocation of tRNA. Biochem Biophys Res Commun 2013; 439:23-9. [PMID: 23958303 DOI: 10.1016/j.bbrc.2013.08.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 08/10/2013] [Indexed: 10/26/2022]
Abstract
Very little is known about how nucleic acids are translocated across membranes. The multi-subunit RNA Import Complex (RIC) from mitochondria of the kinetoplastid protozoon Leishmania tropica induces translocation of tRNAs across artificial or natural membranes, but the nature of the translocation pore remains unknown. We show that subunits RIC6 and RIC9 assemble on the membrane in presence of subunit RIC4A to form complex R3. Atomic Force Microscopy of R3 revealed particles with an asymmetric surface groove of ∼20 nm rim diameter and ∼1 nm depth. R3 induced translocation of tRNA into liposomes when the pH of the medium was lowered to ∼6 in the absence of ATP. R3-mediated tRNA translocation could also be induced at neutral pH by a K(+) diffusion potential with an optimum of 60-70 mV. Point mutations in the Cys2-His2 Fe-binding motif of RIC6, which is homologous to the respiratory Complex III Fe-S protein, abrogated import induced by low pH but not by K(+) diffusion potential. These results indicate that the R3 complex forms a pore that is gated by a proton-generated membrane potential and that the Fe-S binding region of RIC6 has a role in proton translocation. The tRNA import complex of L. tropica thus contains a novel macromolecular channel distinct from the mitochondrial protein import pore that is apparently involved in tRNA import in some species.
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Affiliation(s)
- Sandip Koley
- Genetic Engineering Laboratory, Molecular and Human Genetics Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Calcutta 700 032, India
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13
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Sokhi UK, Das SK, Dasgupta S, Emdad L, Shiang R, DeSalle R, Sarkar D, Fisher PB. Human polynucleotide phosphorylase (hPNPaseold-35): should I eat you or not--that is the question? Adv Cancer Res 2013; 119:161-90. [PMID: 23870512 DOI: 10.1016/b978-0-12-407190-2.00005-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
RNA degradation plays a fundamental role in maintaining cellular homeostasis whether it occurs as a surveillance mechanism eliminating aberrant mRNAs or during RNA processing to generate mature transcripts. 3'-5' exoribonucleases are essential mediators of RNA decay pathways, and one such evolutionarily conserved enzyme is polynucleotide phosphorylase (PNPase). The human homologue of this fascinating enzymatic protein (hPNPaseold-35) was cloned a decade ago in the context of terminal differentiation and senescence through a novel "overlapping pathway screening" approach. Since then, significant insights have been garnered about this exoribonuclease and its repertoire of expanding functions. The objective of this review is to provide an up-to-date perspective of the recent discoveries made relating to hPNPaseold-35 and the impact they continue to have on our comprehension of its expanding and diverse array of functions.
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14
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Sripada L, Tomar D, Singh R. Mitochondria: One of the destinations of miRNAs. Mitochondrion 2012; 12:593-9. [DOI: 10.1016/j.mito.2012.10.009] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 08/22/2012] [Accepted: 10/09/2012] [Indexed: 01/15/2023]
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15
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Jash S, Adhya S. Induction of muscle regeneration by RNA-mediated mitochondrial restoration. FASEB J 2012; 26:4187-97. [PMID: 22751011 DOI: 10.1096/fj.11-203232] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Skeletal muscle injury is associated with general down-regulation of mitochondrial function. Postinjury regeneration of skeletal muscle occurs through activation, proliferation, and differentiation of resident stem cells, including satellite cells and endothelial precursor cells. We wanted to determine the role of mitochondrial function in the regeneration process. Using a previously described method for complex-mediated delivery to intracellular mitochondria, a combination of polycistronic RNAs encoding the H strand of the rat mitochondrial genome was administered to injured rat quadriceps muscle, resulting in restoration of mitochondrial mRNA levels, organellar translation, and respiratory capacity. Intramuscular ATP levels were elevated on pcRNA treatment of injured muscle; concomitantly, levels of reactive oxygen species in the injured muscle were reduced. These effects combined to produce a notable increase in the rate of wound resolution, accompanied by reduction of fibrosis and acceleration of myogenesis, vasculogenesis, and resumption of muscle contractile function. There was evidence of proliferation of Pax7+ satellite cells, expression of muscle-specific regulatory factors in a specific time sequence, and formation of new myofibers in the regenerating muscle. RNA-induced wound resolution and satellite cell proliferation were sensitive to mitochondrial inhibitors, indicating the importance of oxidative phosphorylation. These results highlight the activation of endogenous stem cells through mitochondrial restoration as a possible alternative to implantation of cultured stem cells.
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Affiliation(s)
- Sukanta Jash
- Genetic Engineering Laboratory, Indian Institute of Chemical Biology, CSIR, 4 Raja S. C. Mullick Rd., Calcutta 700032, India
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16
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Niazi AK, Mileshina D, Cosset A, Val R, Weber-Lotfi F, Dietrich A. Targeting nucleic acids into mitochondria: progress and prospects. Mitochondrion 2012; 13:548-58. [PMID: 22609422 DOI: 10.1016/j.mito.2012.05.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 05/14/2012] [Indexed: 12/18/2022]
Abstract
Given the essential functions of these organelles in cell homeostasis, their involvement in incurable diseases and their potential in biotechnological applications, genetic transformation of mitochondria has been a long pursued goal that has only been reached in a couple of unicellular organisms. The challenge led scientists to explore a wealth of different strategies for mitochondrial delivery of DNA or RNA in living cells. These are the subject of the present review. Targeting DNA into the organelles currently shows promise but remarkably a number of alternative approaches based on RNA trafficking were also established and will bring as well major contributions.
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Affiliation(s)
- Adnan Khan Niazi
- Institut de Biologie Moléculaire des Plantes, CNRS and Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
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17
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Modulation of mitochondrial respiratory capacity by carrier-mediated transfer of RNA in vivo. Mitochondrion 2012; 12:262-70. [DOI: 10.1016/j.mito.2011.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 09/05/2011] [Accepted: 10/10/2011] [Indexed: 11/22/2022]
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18
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Seidman D, Johnson D, Gerbasi V, Golden D, Orlando R, Hajduk S. Mitochondrial membrane complex that contains proteins necessary for tRNA import in Trypanosoma brucei. J Biol Chem 2012; 287:8892-903. [PMID: 22267727 DOI: 10.1074/jbc.m111.300186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial genome of Trypanosoma brucei does not contain genes encoding tRNAs; instead this protozoan parasite must import nuclear-encoded tRNAs from the cytosol for mitochondrial translation. Previously, it has been shown that mitochondrial tRNA import requires ATP hydrolysis and a proteinaceous mitochondrial membrane component. However, little is known about the mitochondrial membrane proteins involved in tRNA binding and translocation into the mitochondrion. Here we report the purification of a mitochondrial membrane complex using tRNA affinity purification and have identified several protein components of the putative tRNA translocon by mass spectrometry. Using an in vivo tRNA import assay in combination with RNA interference, we have verified that two of these proteins, Tb11.01.4590 and Tb09.v1.0420, are involved in mitochondrial tRNA import. Using Protein C Epitope -Tobacco Etch Virus-Protein A Epitope (PTP)-tagged Tb11.01.4590, additional associated proteins were identified including Tim17 and other mitochondrial proteins necessary for mitochondrial protein import. Results presented here identify and validate two novel protein components of the putative tRNA translocon and provide additional evidence that mitochondrial tRNA and protein import have shared components in trypanosomes.
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Affiliation(s)
- David Seidman
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-7229, USA
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19
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Homblé F, Krammer EM, Prévost M. Plant VDAC: facts and speculations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1486-501. [PMID: 22155681 DOI: 10.1016/j.bbamem.2011.11.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/12/2011] [Accepted: 11/22/2011] [Indexed: 01/01/2023]
Abstract
The voltage-dependent anion-selective channel (VDAC) is the most abundant protein in the mitochondrial outer membrane and the major transport pathway for a large variety of compounds ranging from ions to large polymeric molecules such as DNA and tRNA. Plant VDACs feature a secondary structure content and electrophysiological properties akin to those of VDACs from other organisms. They however undergo a specific regulation. The general importance of VDAC in plant physiology has only recently emerged. Besides their role in metabolite transport, plant VDACs are also involved in the programmed cell death triggered in response to biotic and abiotic stresses. Moreover, their colocalization in non-mitochondrial membranes suggests a diversity of function. This review summarizes our current understanding of the structure and function of plant VDACs. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism.
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Affiliation(s)
- Fabrice Homblé
- Structure et Fontion des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles, Boulevard du Triomphe CP, Brussels, Belgium.
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20
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Rubio MAT, Hopper AK. Transfer RNA travels from the cytoplasm to organelles. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:802-17. [PMID: 21976284 DOI: 10.1002/wrna.93] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Transfer RNAs (tRNAs) encoded by the nuclear genome are surprisingly dynamic. Although tRNAs function in protein synthesis occurring on cytoplasmic ribosomes, tRNAs can transit from the cytoplasm to the nucleus and then again return to the cytoplasm by a process known as the tRNA retrograde process. Subsets of the cytoplasmic tRNAs are also imported into mitochondria and function in mitochondrial protein synthesis. The numbers of tRNA species that are imported into mitochondria differ among organisms, ranging from just a few to the entire set needed to decode mitochondrially encoded mRNAs. For some tRNAs, import is dependent on the mitochondrial protein import machinery, whereas the majority of tRNA mitochondrial import is independent of this machinery. Although cytoplasmic proteins and proteins located on the mitochondrial surface participating in the tRNA import process have been described for several organisms, the identity of these proteins differ among organisms. Likewise, the tRNA determinants required for mitochondrial import differ among tRNA species and organisms. Here, we present an overview and discuss the current state of knowledge regarding the mechanisms involved in the tRNA retrograde process and continue with an overview of tRNA import into mitochondria. Finally, we highlight areas of future research to understand the function and regulation of movement of tRNAs between the cytoplasm and organelles.
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Affiliation(s)
- Mary Anne T Rubio
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
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21
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In vivo study in Trypanosoma brucei links mitochondrial transfer RNA import to mitochondrial protein import. EMBO Rep 2011; 12:825-32. [PMID: 21720389 DOI: 10.1038/embor.2011.111] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/21/2011] [Accepted: 05/16/2011] [Indexed: 11/08/2022] Open
Abstract
Trypanosoma brucei imports all mitochondrial transfer RNAs (tRNAs) from the cytosol. By using cell lines that allow independent tetracycline-inducible RNA interference and isopropyl-β-D-thiogalactopyranoside-inducible expression of a tagged tRNA, we show that ablation of Tim17 and mitochondrial heat-shock protein 70, components of the inner-membrane protein translocation machinery, strongly inhibits import of newly synthesized tRNAs. These findings, together with previous results in yeast and plants, suggest that the requirement for mitochondrial protein-import factors might be a conserved feature of mitochondrial tRNA import in all systems.
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22
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Jash S, Adhya S. Suppression of reactive oxygen species in cells with multiple mitochondrial DNA deletions by exogenous protein-coding RNAs. Mitochondrion 2011; 11:607-14. [DOI: 10.1016/j.mito.2011.03.124] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/09/2011] [Accepted: 03/29/2011] [Indexed: 02/02/2023]
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23
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Necessary and sufficient factors for the import of transfer RNA into the kinetoplast mitochondrion. EMBO Rep 2011. [DOI: 10.1038/embor.2011.94] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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24
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Paris Z, Hashimi H, Lun S, Alfonzo JD, Lukeš J. Futile import of tRNAs and proteins into the mitochondrion of Trypanosoma brucei evansi. Mol Biochem Parasitol 2011; 176:116-20. [PMID: 21195112 PMCID: PMC3042029 DOI: 10.1016/j.molbiopara.2010.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 12/17/2010] [Accepted: 12/22/2010] [Indexed: 11/30/2022]
Abstract
Trypanosoma brucei brucei has two distinct developmental stages, the procyclic stage in the insect and the bloodstream stage in the mammalian host. The significance of each developmental stage is punctuated by specific changes in metabolism. In the insect, T. b. brucei is strictly dependent on mitochondrial function and thus respiration to generate the bulk of its ATP, whereas in the mammalian host it relies heavily on glycolysis. These observations have raised questions about the importance of mitochondrial function in the bloodstream stage. Peculiarly, akinetoplastic strains of Trypanosoma brucei evansi that lack mitochondrial DNA do exist in the wild and are developmentally locked in the glycolysis-dependent bloodstream stage. Using RNAi we show that two mitochondrion-imported proteins, mitochondrial RNA polymerase and guide RNA associated protein 1, are still imported into the nucleic acids-lacking organelle of T. b. evansi, making the need for these proteins futile. We also show that, like in the T. b. brucei procyclic stage, the mitochondria of both bloodstream stage of T. b. brucei and T. b. evansi import various tRNAs, including those that undergo thiolation. However, we were unable to detect mitochondrial thiolation in the akinetoplastic organelle. Taken together, these data suggest a lack of connection between nuclear and mitochondrial communication in strains of T. b. evansi that lost mitochondrial genome and that do not required an insect vector for survival.
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Affiliation(s)
- Zdenĕk Paris
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
| | - Hassan Hashimi
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Sijia Lun
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
| | - Juan D. Alfonzo
- Department of Microbiology and OSU Center for RNA Biology, The Ohio State University, Columbus, 43210 Ohio, USA
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
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25
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RNA-mediated restoration of mitochondrial function in cells harboring a Kearns Sayre Syndrome mutation. Mitochondrion 2011; 11:564-74. [PMID: 21406250 DOI: 10.1016/j.mito.2011.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/03/2011] [Indexed: 11/20/2022]
Abstract
Mutations in mitochondrial DNA (mtDNA) generate multi-system disorders due to failure of ATP production. A cybrid containing a 1.9-kb mtDNA deletion from a patient with Kearns Sayre Syndrome is respiration-defective and grows glycolytically. When treated with a ribonucleoprotein (RNP) complex of polycistronic RNA 1 (pcRNA1) containing mtDNA-encoded genes and a multi-subunit carrier complex R8, full-length pcRNA1 was transported to mitochondria. Translation of the pcRNA1-encoded mRNAs was observed in mitochondria from RNP-treated cells. Respiration of the cybrid was rescued to approximately 90% of normal within hours, switching the cells to aerobic growth. These findings have implications for the development of effective mitochondrial gene therapy.
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26
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Cristodero M, Seebeck T, Schneider A. Mitochondrial translation is essential in bloodstream forms of Trypanosoma brucei. Mol Microbiol 2010; 78:757-69. [PMID: 20969649 DOI: 10.1111/j.1365-2958.2010.07368.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The parasitic protozoa Trypanosoma brucei has a complex life cycle. Oxidative phosphorylation is highly active in the procyclic form but absent from bloodstream cells. The mitochondrial genome encodes several gene products that are required for oxidative phosphorylation, but it completely lacks tRNA genes. For mitochondrial translation to occur, the import of cytosolic tRNAs is therefore essential for procyclic T. brucei. Whether the same is true for the bloodstream form has not been studied so far. Here we show that the steady-state levels of mitochondrial tRNAs are essentially the same in both life stages. Editing of the imported tRNA(Trp) also occurs in both forms as well as in mitochondria of Trypanosoma evansi, which lacks a genome and a translation system. These results show that mitochondrial tRNA import is a constitutive process that must be mediated by proteins that are expressed in both forms of the life cycle and that are not encoded in the mitochondrial genome. Moreover, bloodstream cells lacking either mitochondria-specific translation elongation factor Tu or mitochondrial tryptophanyl-tRNA synthetase are not viable indicating that mitochondrial translation is also essential in this stage. Both of these proteins show trypanosomatid-specific features and may therefore be excellent novel drug targets.
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Affiliation(s)
- Marina Cristodero
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland
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27
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Wang G, Chen HW, Oktay Y, Zhang J, Allen EL, Smith GM, Fan KC, Hong JS, French SW, McCaffery JM, Lightowlers RN, Morse HC, Koehler CM, Teitell MA. PNPASE regulates RNA import into mitochondria. Cell 2010; 142:456-67. [PMID: 20691904 DOI: 10.1016/j.cell.2010.06.035] [Citation(s) in RCA: 270] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/20/2010] [Accepted: 05/13/2010] [Indexed: 02/04/2023]
Abstract
RNA import into mammalian mitochondria is considered essential for replication, transcription, and translation of the mitochondrial genome but the pathway(s) and factors that control this import are poorly understood. Previously, we localized polynucleotide phosphorylase (PNPASE), a 3' --> 5' exoribonuclease and poly-A polymerase, in the mitochondrial intermembrane space, a location lacking resident RNAs. Here, we show a new role for PNPASE in regulating the import of nuclear-encoded RNAs into the mitochondrial matrix. PNPASE reduction impaired mitochondrial RNA processing and polycistronic transcripts accumulated. Augmented import of RNase P, 5S rRNA, and MRP RNAs depended on PNPASE expression and PNPASE-imported RNA interactions were identified. PNPASE RNA processing and import activities were separable and a mitochondrial RNA targeting signal was isolated that enabled RNA import in a PNPASE-dependent manner. Combined, these data strongly support an unanticipated role for PNPASE in mediating the translocation of RNAs into mitochondria.
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Affiliation(s)
- Geng Wang
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA
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28
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Kolesnikova O, Kazakova H, Comte C, Steinberg S, Kamenski P, Martin RP, Tarassov I, Entelis N. Selection of RNA aptamers imported into yeast and human mitochondria. RNA (NEW YORK, N.Y.) 2010; 16:926-941. [PMID: 20348443 PMCID: PMC2856887 DOI: 10.1261/rna.1914110] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 02/01/2010] [Indexed: 05/29/2023]
Abstract
In the yeast Saccharomyces cerevisiae, nuclear DNA-encoded is partially imported into mitochondria. We previously found that the synthetic transcripts of yeast tRNA(Lys) and a number of their mutant versions could be specifically internalized by isolated yeast and human mitochondria. The mitochondrial targeting of tRNA(Lys) in yeast was shown to depend on the cytosolic precursor of mitochondrial lysyl-tRNA synthetase and the glycolytic enzyme enolase. Here we applied the approach of in vitro selection (SELEX) to broaden the spectrum of importable tRNA-derived molecules. We found that RNAs selected for their import into isolated yeast mitochondria have lost the potential to acquire a classical tRNA-shape. Analysis of conformational rearrangements in the importable RNAs by in-gel fluorescence resonance energy transfer (FRET) approach permitted us to suggest that protein factor binding and subsequent import require formation of an alternative structure, different from a classic L-form tRNA model. We show that in the complex with targeting protein factor, enolase 2, tRK1 adopts a particular conformation characterized by bringing together the 3'-end and the TPsiC loop. This is a first evidence for implication of RNA secondary structure rearrangement in the mechanism of mitochondrial import selectivity. Based on these data, a set of small RNA molecules with significantly improved efficiency of import into yeast and human mitochondria was constructed, opening the possibility of creating a new mitochondrial vector system able to target therapeutic oligoribonucleotides into deficient human mitochondria.
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MESH Headings
- Aptamers, Nucleotide/chemistry
- Aptamers, Nucleotide/genetics
- Aptamers, Nucleotide/metabolism
- Base Sequence
- Biological Transport, Active
- Fluorescence Resonance Energy Transfer
- Humans
- In Vitro Techniques
- Lysine-tRNA Ligase/metabolism
- Mitochondria/metabolism
- Models, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phosphopyruvate Hydratase/metabolism
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- SELEX Aptamer Technique
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Olga Kolesnikova
- UMR 7156, Université de Strasbourg/Centre National de la Recherche Scientifique (UdS/CNRS), 67084 Strasbourg, France
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29
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Lithgow T, Schneider A. Evolution of macromolecular import pathways in mitochondria, hydrogenosomes and mitosomes. Philos Trans R Soc Lond B Biol Sci 2010; 365:799-817. [PMID: 20124346 PMCID: PMC2817224 DOI: 10.1098/rstb.2009.0167] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
All eukaryotes require mitochondria for survival and growth. The origin of mitochondria can be traced down to a single endosymbiotic event between two probably prokaryotic organisms. Subsequent evolution has left mitochondria a collection of heterogeneous organelle variants. Most of these variants have retained their own genome and translation system. In hydrogenosomes and mitosomes, however, the entire genome was lost. All types of mitochondria import most of their proteome from the cytosol, irrespective of whether they have a genome or not. Moreover, in most eukaryotes, a variable number of tRNAs that are required for mitochondrial translation are also imported. Thus, import of macromolecules, both proteins and tRNA, is essential for mitochondrial biogenesis. Here, we review what is known about the evolutionary history of the two processes using a recently revised eukaryotic phylogeny as a framework. We discuss how the processes of protein import and tRNA import relate to each other in an evolutionary context.
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Affiliation(s)
- Trevor Lithgow
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland
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30
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Alfonzo JD, Söll D. Mitochondrial tRNA import--the challenge to understand has just begun. Biol Chem 2009; 390:717-22. [PMID: 19558325 DOI: 10.1515/bc.2009.101] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mitochondrial translation is important for the synthesis of proteins involved in oxidative phosphorylation, which yields the bulk of the ATP made in cells. During evolution most mitochondria-containing organisms have lost tRNA genes from their mitochondrial genomes. Thus, to support the essential process of nuanced mitochondrial translation, mechanisms to actively transport tRNAs from the cytoplasm across the mitochondrial membranes into the mitochondrion have evolved. Here, we review the currently known tRNA import mechanisms, comment on recent discoveries of various import factors, and suggest a rationale for forces that lie behind the evolution of mitochondrial tRNA import.
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Affiliation(s)
- Juan D Alfonzo
- Department of Microbiology, Ohio State University Biochemistry Program and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA.
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31
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Paris Z, Rubio MAT, Lukes J, Alfonzo JD. Mitochondrial tRNA import in Trypanosoma brucei is independent of thiolation and the Rieske protein. RNA (NEW YORK, N.Y.) 2009; 15:1398-1406. [PMID: 19465685 PMCID: PMC2704085 DOI: 10.1261/rna.1589109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 04/13/2009] [Indexed: 05/27/2023]
Abstract
Due to a complete lack of the tRNA genes in the mitochondrial genome of Trypanosoma brucei, all tRNAs needed for mitochondrial translation have to be imported into the organelle from the cytosol. A previous study showed that the modified nucleotide s(2)U could act as a negative determinant for mitochondrial tRNA import in another kinetoplastid, Leishmania tarentolae. We have investigated whether the same type of cytosolic control for tRNA retention exists in T. brucei. Based on Northern analysis with subcellular RNA fractions and in vitro import assays, we demonstrate that silencing of the cysteine desulfurase, TbNfs (TbIscS), the key enzyme in tRNA thiolation (s(2)U) and Fe-S cluster formation in vivo, has no effect on tRNA partitioning. This observation is especially surprising in light of a recent report suggesting that in L. tropica the Rieske Fe-S protein is an essential component of the RNA import complex (RIC). In line with the above observation, we also show that down-regulation of the Rieske protein by RNA interference, similar to the TbNfs knockdowns, has no effect on import. The data presented here supports the view that in T. brucei: (1) s(2)U is not a negative determinant for tRNA import; (2) the Rieske protein is not an essential component of the import machinery, and (3) since the Rieske protein is essential for respiration and maintenance of inner mitochondrial membrane potential, neither process plays a critical role in tRNA import. We therefore suggest that the T. brucei import machinery differs substantially from what has been described in Leishmania.
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Affiliation(s)
- Zdenek Paris
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005 Ceské Budejovice (Budweis), Czech Republic
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32
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Necessary and sufficient factors for the import of transfer RNA into the kinetoplast mitochondrion. EMBO Rep 2009. [DOI: 10.1038/embor.2008.241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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33
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Duchêne AM, Pujol C, Maréchal-Drouard L. Import of tRNAs and aminoacyl-tRNA synthetases into mitochondria. Curr Genet 2008; 55:1-18. [PMID: 19083240 DOI: 10.1007/s00294-008-0223-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/21/2008] [Accepted: 11/24/2008] [Indexed: 12/13/2022]
Abstract
During evolution, most of the bacterial genes from the ancestral endosymbiotic alpha-proteobacteria at the origin of mitochondria have been either lost or transferred to the nuclear genome. A crucial evolutionary step was the establishment of macromolecule import systems to allow the come back of proteins and RNAs into the organelle. Paradoxically, the few mitochondria-encoded protein genes remain essential and must be translated by a mitochondrial translation machinery mainly constituted by nucleus-encoded components. Two crucial partners of the mitochondrial translation machinery are the aminoacyl-tRNA synthetases and the tRNAs. All mitochondrial aminoacyl-tRNA synthetases and many tRNAs are imported from the cytosol into the mitochondria in eukaryotic cells. During the last few years, their origin and their import into the organelle have been studied in evolutionary distinct organisms and we review here what is known in this field.
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Affiliation(s)
- Anne-Marie Duchêne
- Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche du CNRS, Associated with Louis Pasteur University, 12 rue du Général Zimmer, 67084, Strasbourg Cedex, France.
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34
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Structural and functional association of Trypanosoma brucei MIX protein with cytochrome c oxidase complex. EUKARYOTIC CELL 2008; 7:1994-2003. [PMID: 18776036 PMCID: PMC2583542 DOI: 10.1128/ec.00204-08] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A mitochondrial inner membrane protein, designated MIX, seems to be essential for cell viability. The deletion of both alleles was not possible, and the deletion of a single allele led to a loss of virulence and aberrant mitochondrial segregation and cell division in Leishmania major. However, the mechanism by which MIX exerts its effect has not been determined. We show here that MIX is also expressed in the mitochondrion of Trypanosoma brucei, and using RNA interference, we found that its loss leads to a phenotype that is similar to that described for Leishmania. The loss of MIX also had a major effect on cytochrome c oxidase activity, on the mitochondrial membrane potential, and on the production of mitochondrial ATP by oxidative phosphorylation. Using a tandem affinity purification tag, we found that MIX is associated with a multiprotein complex that contains subunits of the mitochondrial cytochrome c oxidase complex (respiratory complex IV), the composition of which was characterized in detail. The specific function of MIX is unknown, but it appears to be important for the function of complex IV and for mitochondrial segregation and cell division in T. brucei.
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Mather MW, Vaidya AB. Mitochondria in malaria and related parasites: ancient, diverse and streamlined. J Bioenerg Biomembr 2008; 40:425-33. [PMID: 18814021 DOI: 10.1007/s10863-008-9176-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 08/23/2008] [Indexed: 10/21/2022]
Abstract
Parasitic organisms have emerged from nearly every corner of the eukaryotic kingdom and hence display tremendous diversity of form and function. This diversity extends to their mitochondria and mitochondrion-derived organelles. While the principles of the chemiosmotic theory apply to all these pathogens, the differences from their hosts provide opportunities for therapeutic development. In this review we discuss examples of mitochondrial systems from a deep-branching phylum, Apicomplexa. Many important human pathogens, such as malaria parasites, belong to this phylum. Unique features of their mitochondria are validated targets for drugs that are selectively toxic to the parasites.
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Affiliation(s)
- Michael W Mather
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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36
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Home P, Mukherjee S, Adhya S. A mosaic of RNA binding and protein interaction motifs in a bifunctional mitochondrial tRNA import factor from Leishmania tropica. Nucleic Acids Res 2008; 36:5552-61. [PMID: 18755708 PMCID: PMC2553583 DOI: 10.1093/nar/gkn536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proteins that participate in the import of cytosolic tRNAs into mitochondria have been identified in several eukaryotic species, but the details of their interactions with tRNA and other proteins are unknown. In the kinetoplastid protozoon Leishmania tropica, multiple proteins are organized into a functional import complex. RIC8A, a tRNA-binding subunit of this complex, has a C-terminal domain that functions as subunit 6b of ubiquinol cytochrome c reductase (complex III). We show that the N-terminal domain, unique to kinetoplastid protozoa, is structurally similar to the appended S15/NS1 RNA-binding domain of aminoacyl tRNA synthetases, with a helix–turn–helix motif. Structure-guided mutagenesis coupled with in vitro assays showed that helix α1 contacts tRNA whereas helix α2 targets the protein for assembly into the import complex. Inducible expression of a helix 1-deleted variant in L. tropica resulted in formation of an inactive import complex, while the helix 2-deleted variant was unable to assemble in vivo. Moreover, a protein-interaction assay showed that the C-terminal domain makes allosteric contacts with import receptor RIC1 complexed with tRNA. These results help explain the origin of the bifunctionality of RIC8A, and the allosteric changes accompanying docking and release of tRNA during import.
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Affiliation(s)
- Pratik Home
- Genetic Engineering Laboratory, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
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37
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Lee M, Choi JS, Ko KS. Mitochondria targeting delivery of nucleic acids. Expert Opin Drug Deliv 2008; 5:879-87. [DOI: 10.1517/17425247.5.8.879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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38
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Salinas T, Duchêne AM, Maréchal-Drouard L. Recent advances in tRNA mitochondrial import. Trends Biochem Sci 2008; 33:320-9. [DOI: 10.1016/j.tibs.2008.04.010] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 04/22/2008] [Accepted: 04/22/2008] [Indexed: 02/02/2023]
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39
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Kyriakouli DS, Boesch P, Taylor RW, Lightowlers RN. Progress and prospects: gene therapy for mitochondrial DNA disease. Gene Ther 2008; 15:1017-23. [DOI: 10.1038/gt.2008.91] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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40
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Basu S, Mukherjee S, Adhya S. Proton-guided movements of tRNA within the Leishmania mitochondrial RNA import complex. Nucleic Acids Res 2008; 36:1599-609. [PMID: 18250088 PMCID: PMC2275131 DOI: 10.1093/nar/gkn010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The RNA import complex (RIC) from the mitochondrion of the kinetoplastid protozoan Leishmania tropica contains two subunits that directly bind to import signals on two distinct subsets of tRNA and interact with each other allosterically. What happens to the tRNA subsequent to its loading on the complex is unknown. A third subunit-RIC9-has intrinsic affinity for both types of tRNA and is essential for import in vivo. Here we show that antibody against RIC9 inhibited the import of both types of tRNA into mitoplasts in vitro, but failed to inhibit the binding of these tRNAs to their respective receptors, indicating that RIC9 acts in a subsequent step. Using photoaffinity crosslinking-immunoprecipitation to detect translocation intermediates, it was observed that tRNA was transferred from its cognate receptor to RIC9, followed by translocation across the membrane and release as free tRNA in the inner compartment. Transfer required elevated temperatures and ATP, but ATP was substituted by acid pH. These tRNA movements were sensitive to uncouplers and inhibitors, suggesting distinct roles of the electrical and chemical components of the proton motive force generated by vectorial proton translocation accompanying ATP hydrolysis. By analysis of partially assembled complexes in L. tropica depleted of various subunits, and in vitro assembly assays, RIC9 was shown to make stable contacts with RIC8A, a tRNA receptor and RIC6, a membrane-embedded component. The results have implications for the mechanism of tRNA import.
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Affiliation(s)
- Sudarshana Basu
- Genetic Engineering Laboratory, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Calcutta 700 032, India
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41
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Mukherjee S, Mahata B, Mahato B, Adhya S. Targeted mRNA degradation by complex-mediated delivery of antisense RNAs to intracellular human mitochondria. Hum Mol Genet 2008; 17:1292-8. [DOI: 10.1093/hmg/ddn017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Adhya S. Leishmania mitochondrial tRNA importers. Int J Biochem Cell Biol 2007; 40:2681-5. [PMID: 18061510 DOI: 10.1016/j.biocel.2007.10.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 11/28/2022]
Abstract
The RNA Import Complex (RIC) is a multi-subunit protein complex from the mitochondria of the kinetoplastid protozoon Leishmania tropica that induces transport of tRNA across natural and artificial membranes. Leishmania, Trypanosoma and related genera of the order Kinetoplastidae are early diverging, atypical eukaryotes with unique RNA metabolic pathways, including the import of nucleus-encoded tRNAs into the mitochondrion to complement the deletion of all organelle-encoded tRNA genes. Biochemical and genetic studies of RIC are contributing to greater understanding of the mechanism of import. Additionally, RIC was shown to act as an efficient delivery vehicle for tRNA and other small RNAs into mitochondria within intact mammalian cells, indicating its applicability to the management of diseases caused by mitochondrial mutations.
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Affiliation(s)
- Samit Adhya
- Genetic Engineering Laboratory, Division of Molecular and Human Genetics, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Calcutta 700032, India.
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43
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Affiliation(s)
- Marc Mirande
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
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