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Bakare AB, Lesnefsky EJ, Iyer S. Leigh Syndrome: A Tale of Two Genomes. Front Physiol 2021; 12:693734. [PMID: 34456746 PMCID: PMC8385445 DOI: 10.3389/fphys.2021.693734] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/22/2021] [Indexed: 12/21/2022] Open
Abstract
Leigh syndrome is a rare, complex, and incurable early onset (typically infant or early childhood) mitochondrial disorder with both phenotypic and genetic heterogeneity. The heterogeneous nature of this disorder, based in part on the complexity of mitochondrial genetics, and the significant interactions between the nuclear and mitochondrial genomes has made it particularly challenging to research and develop therapies. This review article discusses some of the advances that have been made in the field to date. While the prognosis is poor with no current substantial treatment options, multiple studies are underway to understand the etiology, pathogenesis, and pathophysiology of Leigh syndrome. With advances in available research tools leading to a better understanding of the mitochondria in health and disease, there is hope for novel treatment options in the future.
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Affiliation(s)
- Ajibola B. Bakare
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Edward J. Lesnefsky
- Division of Cardiology, Pauley Heart Center, Department of Internal Medicine, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Physiology/Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biochemistry and Molecular Biology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Shilpa Iyer
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
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Cytochrome c oxidase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148335. [PMID: 33171185 DOI: 10.1016/j.bbabio.2020.148335] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 12/23/2022]
Abstract
Cytochrome c oxidase (COX) deficiency is characterized by a high degree of genetic and phenotypic heterogeneity, partly reflecting the extreme structural complexity, multiple post-translational modification, variable, tissue-specific composition, and the high number of and intricate connections among the assembly factors of this enzyme. In fact, decreased COX specific activity can manifest with different degrees of severity, affect the whole organism or specific tissues, and develop a wide spectrum of disease natural history, including disease onsets ranging from birth to late adulthood. More than 30 genes have been linked to COX deficiency, but the list is still incomplete and in fact constantly updated. We here discuss the current knowledge about COX in health and disease, focusing on genetic aetiology and link to clinical manifestations. In addition, information concerning either fundamental biological features of the enzymes or biochemical signatures of its defects have been provided by experimental in vivo models, including yeast, fly, mouse and fish, which expanded our knowledge on the functional features and the phenotypical consequences of different forms of COX deficiency.
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Wang Y, Zhou JB, Zeng QY, Wu S, Xue MQ, Fang P, Wang ED, Zhou XL. Hearing impairment-associated KARS mutations lead to defects in aminoacylation of both cytoplasmic and mitochondrial tRNA Lys. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1227-1239. [PMID: 32189241 DOI: 10.1007/s11427-019-1619-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/03/2020] [Indexed: 01/20/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are ubiquitously expressed, essential enzymes, synthesizing aminoacyl-tRNAs for protein synthesis. Functional defects of aaRSs frequently cause various human disorders. Human KARS encodes both cytosolic and mitochondrial lysyl-tRNA synthetases (LysRSs). Previously, two mutations (c.1129G>A and c.517T>C) were identified that led to hearing impairment; however, the underlying biochemical mechanism is unclear. In the present study, we found that the two mutations have no impact on the incorporation of LysRS into the multiple-synthetase complex in the cytosol, but affect the cytosolic LysRS level, its tertiary structure, and cytosolic tRNA aminoacylation in vitro. As for mitochondrial translation, the two mutations have little effect on the steady-state level, mitochondrial targeting, and tRNA binding affinity of mitochondrial LysRS. However, they exhibit striking differences in charging mitochondrial tRNALys, with the c.517T>C mutant being completely deficient in vitro and in vivo. We constructed two yeast genetic models, which are powerful tools to test the in vivo aminoacylation activity of KARS mutations at both the cytosolic and mitochondrial levels. Overall, our data provided biochemical insights into the potentially molecular pathological mechanism of KARS c.1129G>A and c.517T>C mutations and provided yeast genetic bases to investigate other KARS mutations in the future.
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Affiliation(s)
- Yong Wang
- State Key Laboratory of Molecular Biology, 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.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Jing-Bo Zhou
- State Key Laboratory of Molecular Biology, 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
| | - Qi-Yu Zeng
- State Key Laboratory of Molecular Biology, 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
| | - Siqi Wu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Mei-Qin Xue
- State Key Laboratory of Molecular Biology, 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
| | - Pengfei Fang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, 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. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, 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.
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Francisci S, Montanari A. Mitochondrial diseases: Yeast as a model for the study of suppressors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:666-673. [PMID: 28089773 DOI: 10.1016/j.bbamcr.2017.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/22/2016] [Accepted: 01/11/2017] [Indexed: 11/27/2022]
Abstract
Mitochondrial (mt) tRNA gene mutations are an important cause of human morbidity and are associated with different syndromes. We have previously shown that the mitochondrial protein synthesis elongation factor EF-Tu and isolated sequences from the carboxy-terminal domain of yeast and human mt leucyl-tRNA synthetases (LeuRS), have a wide range of suppression capability among different yeast mt tRNA mutants having defective respiratory phenotype. Here we show that the rescuing capability can be restricted to a specific sequence of six amino acids from the carboxy-terminal domain of mt LeuRS. On the other hand by overexpressing a mutated version of mt EF-Tu in a yeast strain deleted for the endogenous nuclear gene we identified the specific region involved in suppression. Results support the possibility that a small peptide could correct defects associated with many mt tRNA mutations, suggesting a novel therapy for mitochondrial diseases treatment. The involvement of the mt EF-Tu in cellular heat stress response has also been suggested.
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Affiliation(s)
- Silvia Francisci
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy.
| | - Arianna Montanari
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; Pasteur Institute Italy - Cenci Bolognetti Foundation, Sapienza University of Rome, Viale Regina Elena, 291, 00161 Rome, Italy.
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5
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Biolistic Transformation for Delivering DNA into the Mitochondria. Fungal Biol 2015. [DOI: 10.1007/978-3-319-10142-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Di Micco P, Fazzi D'Orsi M, Morea V, Frontali L, Francisci S, Montanari A. The yeast model suggests the use of short peptides derived from mt LeuRS for the therapy of diseases due to mutations in several mt tRNAs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:3065-74. [PMID: 25261707 DOI: 10.1016/j.bbamcr.2014.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 01/23/2023]
Abstract
We have previously established a yeast model of mitochondrial (mt) diseases. We showed that defective respiratory phenotypes due to point-mutations in mt tRNA(Leu(UUR)), tRNA(Ile) and tRNA(Val) could be relieved by overexpression of both cognate and non-cognate nuclearly encoded mt aminoacyl-tRNA synthetases (aaRS) LeuRS, IleRS and ValRS. More recently, we showed that the isolated carboxy-terminal domain (Cterm) of yeast mt LeuRS, and even short peptides derived from the human Cterm, have the same suppressing abilities as the whole enzymes. In this work, we extend these results by investigating the activity of a number of mt aaRS from either class I or II towards a panel of mt tRNAs. The Cterm of both human and yeast mt LeuRS has the same spectrum of activity as mt aaRS belonging to class I and subclass a, which is the most extensive among the whole enzymes. Yeast Cterm is demonstrated to be endowed with mt targeting activity. Importantly, peptide fragments β30_31 and β32_33, derived from the human Cterm, have even higher efficiency as well as wider spectrum of activity, thus opening new avenues for therapeutic intervention. Bind-shifting experiments show that the β30_31 peptide directly interacts with human mt tRNA(Leu(UUR)) and tRNA(Ile), suggesting that the rescuing activity of isolated peptide fragments is mediated by a chaperone-like mechanism. Wide-range suppression appears to be idiosyncratic of LeuRS and its fragments, since it is not shared by Cterminal regions derived from human mt IleRS or ValRS, which are expected to have very different structures and interactions with tRNAs.
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Affiliation(s)
- Patrizio Di Micco
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Mario Fazzi D'Orsi
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Veronica Morea
- National Research Council of Italy (CNR) - Institute of Biology, Molecular Medicine and Nanobiotechnology (IBMN), Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Laura Frontali
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Silvia Francisci
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Arianna Montanari
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
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7
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Pathological Mutations of the Mitochondrial Human Genome: the Instrumental Role of the Yeast S. cerevisiae. Diseases 2014. [DOI: 10.3390/diseases2010024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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8
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Montanari A, Zhou YF, D'Orsi MF, Bolotin-Fukuhara M, Frontali L, Francisci S. Analyzing the suppression of respiratory defects in the yeast model of human mitochondrial tRNA diseases. Gene 2013; 527:1-9. [PMID: 23727608 DOI: 10.1016/j.gene.2013.05.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/29/2013] [Accepted: 05/13/2013] [Indexed: 12/01/2022]
Abstract
The respiratory defects associated with mutations in human mitochondrial tRNA genes can be mimicked in yeast, which is the only organism easily amenable to mitochondrial transformation. This approach has shown that overexpression of several nuclear genes coding for factors involved in mitochondrial protein synthesis can alleviate the respiratory defects both in yeast and in human cells. The present paper analyzes in detail the effects of overexpressed yeast and human mitochondrial translation elongation factors EF-Tu. We studied the suppressing activity versus the function in mt translation of mutated versions of this factor and we obtained indications on the mechanism of suppression. Moreover from a more extended search for suppressor genes we isolated factors which might be active in mitochondrial biogenesis. Results indicate that the multiplicity of mitochondrial factors as well as their high variability of expression levels can account for the variable severity of mitochondrial diseases and might suggest possible therapeutic approaches.
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Affiliation(s)
- Arianna Montanari
- Department of Biology and Biotechnologies C. Darwin, Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
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9
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Montanari A, De Luca C, Di Micco P, Morea V, Frontali L, Francisci S. Structural and functional role of bases 32 and 33 in the anticodon loop of yeast mitochondrial tRNAIle. RNA (NEW YORK, N.Y.) 2011; 17:1983-1996. [PMID: 21914842 PMCID: PMC3198592 DOI: 10.1261/rna.2878711] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/20/2011] [Indexed: 05/31/2023]
Abstract
Previous work has demonstrated the usefulness of the yeast model to investigate the molecular mechanisms underlying defects due to base substitutions in mitochondrial tRNA genes, and to identify suppressing molecules endowed with potential clinical relevance. The present paper extends these investigations to two human equivalent yeast mutations located at positions 32 and 33 in the anticodon loop of tRNA(Ile). Notwithstanding the proximity of the two T>C base substitutions, the effects of these mutations have been found to be quite different in yeast, as they are in human. The T32C substitution has a very severe effect in yeast, consisting in a complete inhibition of growth on nonfermentable substrates. Conversely, respiratory defects caused by the T33C mutation could only be observed in a defined genetic context. Analyses of available sequences and selected tRNA three-dimensional structures were performed to provide explanations for the different behavior of these adjacent mutations. Examination of the effects of previously identified suppressors demonstrated that overexpression of the TUF1 gene did not rescue the defective phenotypes determined by either mutation, possibly as a consequence of the lack of interactions between EF-Tu and the tRNA anticodon arm in known structures. On the contrary, both the cognate IleRS and the noncognate LeuRS and ValRS are endowed with suppressing activities toward both mutations. This allows us to extend to the tRNA(Ile) mutants the cross-suppression activity of aminoacyl-tRNA synthetases previously demonstrated for tRNA(Leu) and tRNA(Val) mutants.
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Affiliation(s)
- Arianna Montanari
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Cristina De Luca
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Patrizio Di Micco
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, 00185 Rome, Italy
| | - Veronica Morea
- CNR—National Research Council of Italy, Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Laura Frontali
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Silvia Francisci
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
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10
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Francisci S, Montanari A, De Luca C, Frontali L. Peptides from aminoacyl-tRNA synthetases can cure the defects due to mutations in mt tRNA genes. Mitochondrion 2011; 11:919-23. [PMID: 21903180 PMCID: PMC3210327 DOI: 10.1016/j.mito.2011.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 07/28/2011] [Accepted: 08/04/2011] [Indexed: 11/29/2022]
Abstract
Recent results from several laboratories have confirmed that human and yeast leucyl- and valyl-tRNA synthetases can rescue the respiratory defects due to mutations in mitochondrial tRNA genes. In this report we show that this effect cannot be ascribed to the catalytic activity per se and that isolated domains of aminoacyl-tRNA synthetases and even short peptides thereof have suppressing effects.
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Affiliation(s)
- Silvia Francisci
- Department of Biology and Biotechnologies Charles Darwin, Pasteur Institute-Cenci Bolognetti Foundation and Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
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11
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Montanari A, De Luca C, Frontali L, Francisci S. Aminoacyl-tRNA synthetases are multivalent suppressors of defects due to human equivalent mutations in yeast mt tRNA genes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1050-7. [DOI: 10.1016/j.bbamcr.2010.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 04/22/2010] [Accepted: 05/05/2010] [Indexed: 12/01/2022]
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12
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Yarham JW, Elson JL, Blakely EL, McFarland R, Taylor RW. Mitochondrial tRNA mutations and disease. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 1:304-24. [DOI: 10.1002/wrna.27] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John W. Yarham
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Joanna L. Elson
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Emma L. Blakely
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert McFarland
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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De Luca C, Zhou Y, Montanari A, Morea V, Oliva R, Besagni C, Bolotin-Fukuhara M, Frontali L, Francisci S. Can yeast be used to study mitochondrial diseases? Biolistic tRNA mutants for the analysis of mechanisms and suppressors. Mitochondrion 2009; 9:408-17. [DOI: 10.1016/j.mito.2009.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 07/07/2009] [Accepted: 07/17/2009] [Indexed: 10/20/2022]
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Mitochondrial DNA mutations and human disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:113-28. [PMID: 19761752 DOI: 10.1016/j.bbabio.2009.09.005] [Citation(s) in RCA: 417] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/04/2009] [Accepted: 09/09/2009] [Indexed: 01/07/2023]
Abstract
Mitochondrial disorders are a group of clinically heterogeneous diseases, commonly defined by a lack of cellular energy due to oxidative phosphorylation (OXPHOS) defects. Since the identification of the first human pathological mitochondrial DNA (mtDNA) mutations in 1988, significant efforts have been spent in cataloguing the vast array of causative genetic defects of these disorders. Currently, more than 250 pathogenic mtDNA mutations have been identified. An ever-increasing number of nuclear DNA mutations are also being reported as the majority of proteins involved in mitochondrial metabolism and maintenance are nuclear-encoded. Understanding the phenotypic diversity and elucidating the molecular mechanisms at the basis of these diseases has however proved challenging. Progress has been hampered by the peculiar features of mitochondrial genetics, an inability to manipulate the mitochondrial genome, and difficulties in obtaining suitable models of disease. In this review, we will first outline the unique features of mitochondrial genetics before detailing the diseases and their genetic causes, focusing specifically on primary mtDNA genetic defects. The functional consequences of mtDNA mutations that have been characterised to date will also be discussed, along with current and potential future diagnostic and therapeutic advances.
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De Luca C, Besagni C, Frontali L, Bolotin-Fukuhara M, Francisci S. Mutations in yeast mt tRNAs: specific and general suppression by nuclear encoded tRNA interactors. Gene 2006; 377:169-76. [PMID: 16777356 DOI: 10.1016/j.gene.2006.04.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 03/30/2006] [Accepted: 04/05/2006] [Indexed: 11/24/2022]
Abstract
Mutations in mitochondrial tRNA genes can produce alterations in tRNA structure resulting in defective mitochondrial protein synthesis and hence respiratory defects. Such defects are often at the origin of neurodegenerative diseases in humans and can be easily studied in yeast since respiratory deficient mutants are viable. Several nuclear encoded tRNA interactors have been shown to rescue the mitochondrial defects due to mutations in mitochondrial tRNAs. Among these, we have identified the gene for the mitochondrial protein synthesis elongation factor EF-Tu and the specific mt aminoacyl-tRNA synthetases. We also observed that the respiratory defects and the effect of the TUF1 over-expression were strongly strain dependent. The importance of the nuclear background in which the mitochondrial mutation is expressed was investigated by changing the nuclear context. Finally, we demonstrated, using the RT-PCR method, the existence of significantly variable levels of the TUF1 transcript among strains with functional and dysfunctional mitochondria.
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Affiliation(s)
- C De Luca
- Department of Cell and Developmental Biology, Pasteur Institute-Cenci Bolognetti Foundation, University of Rome I, Italy
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16
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Francisci S, DE Luca C, Oliva R, Morea V, Tramontano A, Frontali L. Aminoacylation and conformational properties of yeast mitochondrial tRNA mutants with respiratory deficiency. RNA (NEW YORK, N.Y.) 2005; 11:914-27. [PMID: 15923375 PMCID: PMC1370776 DOI: 10.1261/rna.2260305] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We report the identification and characterization of eight yeast mitochondrial tRNA mutants, located in mitochondrial tRNA(Gln), tRNA(Arg2), tRNA(Ile), tRNA(His), and tRNA(Cys), the respiratory phenotypes of which exhibit various degrees of deficiency. The mutations consist in single-base substitutions, insertions, or deletions, and are distributed all over the tRNA sequence and structure. To identify the features responsible for the defective phenotypes, we analyzed the effect of the different mutations on the electrophoretic mobility and efficiency of acylation of the mutated tRNAs in comparison with the respective wild-type molecules. Five of the studied mutations determine both conformational changes and defective acylation, while two have neither or limited effect. However, variations in structure and acylation are not necessarily correlated; the remaining mutation affects the tRNA conformation, but not its acylation properties. Analysis of tRNA structures and of mitochondrial and cytoplasmic yeast tRNA sequences allowed us to propose explanations for the observed defects, which can be ascribed to either the loss of identity nucleotides or, more often, of specific secondary and/or tertiary interactions that are largely conserved in native mitochondrial and cytoplasmic tRNAs.
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Affiliation(s)
- Silvia Francisci
- Department of Cell and Developmental Biology, University of Rome La Sapienza, Italy.
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Heyers O, Walduck AK, Brindley PJ, Bleiss W, Lucius R, Dorbic T, Wittig B, Kalinna BH. Schistosoma mansoni miracidia transformed by particle bombardment infect Biomphalaria glabrata snails and develop into transgenic sporocysts. Exp Parasitol 2003; 105:174-8. [PMID: 14969695 DOI: 10.1016/j.exppara.2003.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2003] [Revised: 09/08/2003] [Accepted: 11/04/2003] [Indexed: 11/29/2022]
Abstract
Miracidia (and adults) of Schistosoma mansoni which had been subjected to particle bombardment with a plasmid DNA encoding enhanced green fluorescent protein (EGFP) under control of the S. mansoni heat shock protein 70 (HSP70) promoter and termination elements were shown to express the reporter gene. Bombarded miracidia were able to penetrate and establish in Biomphalaria glabrata the intermediate host snail. Gold particles could be detected in the germ balls of parasites in paraffin-sections of snail tissue. The bombarded miracidia were able to develop normally and to transform into mother sporocysts. Reporter gene activity could be determined at 10 days post-infection by RT-PCR in snail tissues, but not by microscopy or Western blot which probably reflected sub-optimal expression levels of constructs. Our findings indicated that it is feasible to return transgenic miracidia to the life cycle, a crucial step for the establishment of a transgenesis system for schistosomes.
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Affiliation(s)
- Oliver Heyers
- Department of Molecular Parasitology, Institute for Biology, Humboldt University Berlin, 10115 Berlin, Germany
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18
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Feuermann M, Francisci S, Rinaldi T, De Luca C, Rohou H, Frontali L, Bolotin-Fukuhara M. The yeast counterparts of human 'MELAS' mutations cause mitochondrial dysfunction that can be rescued by overexpression of the mitochondrial translation factor EF-Tu. EMBO Rep 2003; 4:53-8. [PMID: 12524521 PMCID: PMC1315813 DOI: 10.1038/sj.embor.embor713] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2002] [Revised: 10/25/2002] [Accepted: 11/06/2002] [Indexed: 11/09/2022] Open
Abstract
We have taken advantage of the similarity between human and yeast (Saccharomyces cerevisiae) mitochondrial tRNA(Leu)(UUR), and of the possibility of transforming yeast mitochondria, to construct yeast mitochondrial mutations in the gene encoding tRNA(Leu)(UUR) equivalent to the human A3243G, C3256T and T3291C mutations that have been found in patients with the neurodegenerative disease MELAS (for mitochondrial 'myopathy, encephalopathy, lactic acidosis and stroke-like episodes'). The resulting yeast cells (bearing the equivalent mutations A14G, C26T and T69C) were defective for growth on respiratory substrates, exhibited an abnormal mitochondrial morphology, and accumulated mitochondrial DNA deletions at a very high rate, a trait characteristic of severe mitochondrial defects in protein synthesis. This effect was specific at least in the pathogenic mutation T69C, because when we introduced A or G instead of C, the respiratory defect was absent or very mild. All defective phenotypes returned to normal when the mutant cells were transformed by multicopy plasmids carrying the gene encoding the mitochondrial elongation factor EF-Tu. The ability to create and analyse such mutated strains and to select correcting genes should make yeast a good model for the study of tRNAs and their interacting partners and a practical tool for the study of pathological mutations and of tRNA sequence polymorphisms.
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MESH Headings
- Amino Acid Substitution
- Base Sequence
- Biolistics
- DNA, Mitochondrial/genetics
- Gene Expression Regulation, Fungal
- Genetic Vectors/genetics
- Humans
- MELAS Syndrome/genetics
- Mitochondria/physiology
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation, Missense
- Peptide Elongation Factor Tu/genetics
- Peptide Elongation Factor Tu/physiology
- Phenotype
- Point Mutation
- Protein Biosynthesis
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Transfer, Leu/chemistry
- RNA, Transfer, Leu/genetics
- Recombinant Fusion Proteins/physiology
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/physiology
- Sequence Alignment
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- M. Feuermann
- Laboratoire de Génétique Moléculaire, Institut de Génétique et Microbiologie, Bâtiment 400, Université Paris Sud, 91405 Orsay Cedex, France
- These authors contributed equally to the work
| | - S. Francisci
- Pasteur Institute—Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome I 'La Sapienza', Piazzale Aldo Moro 5, I-00185 Rome, Italy
- These authors contributed equally to the work
- Tel/Fax: +39 06 4461980;
| | - T. Rinaldi
- Pasteur Institute—Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome I 'La Sapienza', Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - C. De Luca
- Pasteur Institute—Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome I 'La Sapienza', Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - H. Rohou
- Laboratoire de Génétique Moléculaire, Institut de Génétique et Microbiologie, Bâtiment 400, Université Paris Sud, 91405 Orsay Cedex, France
| | - L. Frontali
- Pasteur Institute—Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome I 'La Sapienza', Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - M. Bolotin-Fukuhara
- Laboratoire de Génétique Moléculaire, Institut de Génétique et Microbiologie, Bâtiment 400, Université Paris Sud, 91405 Orsay Cedex, France
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Abstract
Mitochondrial DNA (mtDNA) encodes a mere 13 polypeptides, all with well-defined cellular functions in mitochondrial energy metabolism. It was first sequenced over two decades ago, yet our understanding of the wider physiological role of mtDNA is surprisingly sketchy. Partly, this reflects the fact that the mitochondrial gene products are essential for life; that is, most mtDNA mutations are expected to be lethal. The technical difficulty of engineering mtDNA mutations has been a major handicap in furthering our understanding of the mitochondrial genetic system. Recent developments now offer some possibilities for the genetic manipulation of mtDNA and for elucidating its contribution to human development, physiology and disease.
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Affiliation(s)
- H T Jacobs
- Institute of Medical Technology and Tampere University Hospital, FIN-33014 University of Tampere, Tampere, Finland.
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20
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Current Awareness. Yeast 2001. [DOI: 10.1002/yea.685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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