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Davey-Young J, Hasan F, Tennakoon R, Rozik P, Moore H, Hall P, Cozma E, Genereaux J, Hoffman KS, Chan PP, Lowe TM, Brandl CJ, O’Donoghue P. Mistranslating the genetic code with leucine in yeast and mammalian cells. RNA Biol 2024; 21:1-23. [PMID: 38629491 PMCID: PMC11028032 DOI: 10.1080/15476286.2024.2340297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2024] [Indexed: 04/19/2024] Open
Abstract
Translation fidelity relies on accurate aminoacylation of transfer RNAs (tRNAs) by aminoacyl-tRNA synthetases (AARSs). AARSs specific for alanine (Ala), leucine (Leu), serine, and pyrrolysine do not recognize the anticodon bases. Single nucleotide anticodon variants in their cognate tRNAs can lead to mistranslation. Human genomes include both rare and more common mistranslating tRNA variants. We investigated three rare human tRNALeu variants that mis-incorporate Leu at phenylalanine or tryptophan codons. Expression of each tRNALeu anticodon variant in neuroblastoma cells caused defects in fluorescent protein production without significantly increased cytotoxicity under normal conditions or in the context of proteasome inhibition. Using tRNA sequencing and mass spectrometry we confirmed that each tRNALeu variant was expressed and generated mistranslation with Leu. To probe the flexibility of the entire genetic code towards Leu mis-incorporation, we created 64 yeast strains to express all possible tRNALeu anticodon variants in a doxycycline-inducible system. While some variants showed mild or no growth defects, many anticodon variants, enriched with G/C at positions 35 and 36, including those replacing Leu for proline, arginine, alanine, or glycine, caused dramatic reductions in growth. Differential phenotypic defects were observed for tRNALeu mutants with synonymous anticodons and for different tRNALeu isoacceptors with the same anticodon. A comparison to tRNAAla anticodon variants demonstrates that Ala mis-incorporation is more tolerable than Leu at nearly every codon. The data show that the nature of the amino acid substitution, the tRNA gene, and the anticodon are each important factors that influence the ability of cells to tolerate mistranslating tRNAs.
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Affiliation(s)
- Josephine Davey-Young
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Farah Hasan
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Rasangi Tennakoon
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Peter Rozik
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Henry Moore
- Department of Biomolecular Engineering, Baskin School of Engineering & UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Peter Hall
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Ecaterina Cozma
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | | | - Patricia P. Chan
- Department of Biomolecular Engineering, Baskin School of Engineering & UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Todd M. Lowe
- Department of Biomolecular Engineering, Baskin School of Engineering & UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Christopher J. Brandl
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Patrick O’Donoghue
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada
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2
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Klein Gunnewiek TM, Verboven AHA, Pelgrim I, Hogeweg M, Schoenmaker C, Renkema H, Beyrath J, Smeitink J, de Vries BBA, Hoen PBAC', Kozicz T, Nadif Kasri N. Sonlicromanol improves neuronal network dysfunction and transcriptome changes linked to m.3243A>G heteroplasmy in iPSC-derived neurons. Stem Cell Reports 2021; 16:2197-2212. [PMID: 34329596 PMCID: PMC8452519 DOI: 10.1016/j.stemcr.2021.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is often caused by an adenine to guanine variant at m.3243 (m.3243A>G) of the MT-TL1 gene. To understand how this pathogenic variant affects the nervous system, we differentiated human induced pluripotent stem cells (iPSCs) into excitatory neurons with normal (low heteroplasmy) and impaired (high heteroplasmy) mitochondrial function from MELAS patients with the m.3243A>G pathogenic variant. We combined micro-electrode array (MEA) measurements with RNA sequencing (MEA-seq) and found reduced expression of genes involved in mitochondrial respiration and presynaptic function, as well as non-cell autonomous processes in co-cultured astrocytes. Finally, we show that the clinical phase II drug sonlicromanol can improve neuronal network activity when treatment is initiated early in development. This was intricately linked with changes in the neuronal transcriptome. Overall, we provide insight in transcriptomic changes in iPSC-derived neurons with high m.3243A>G heteroplasmy, and show the pathology is partially reversible by sonlicromanol.
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Affiliation(s)
- Teun M Klein Gunnewiek
- Department of Medical Imaging, Anatomie, Radboud University Medical Center, Geert Grooteplein 10, Nijmegen, 6525 GA, the Netherlands; Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands
| | - Anouk H A Verboven
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands; Centre for Molecular and Biomolecular Informatics, Radboudumc, Nijmegen, the Netherlands
| | - Iris Pelgrim
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands; Khondrion B.V., Nijmegen, the Netherlands
| | - Mark Hogeweg
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands
| | - Chantal Schoenmaker
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands
| | | | | | | | - Bert B A de Vries
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands
| | - Peter-Bram A C 't Hoen
- Centre for Molecular and Biomolecular Informatics, Radboudumc, Nijmegen, the Netherlands
| | - Tamas Kozicz
- Department of Medical Imaging, Anatomie, Radboud University Medical Center, Geert Grooteplein 10, Nijmegen, 6525 GA, the Netherlands; Department of Laboratory Medicine and Pathology. Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, 55905 Rochester, MN, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, 55905 Rochester, MN, USA.
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, 6500 HB, the Netherlands.
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3
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de Boer E, Ockeloen CW, Matalonga L, Horvath R, Rodenburg RJ, Coenen MJH, Janssen M, Henssen D, Gilissen C, Steyaert W, Paramonov I, Trimouille A, Kleefstra T, Verloes A, Vissers LELM. A MT-TL1 variant identified by whole exome sequencing in an individual with intellectual disability, epilepsy, and spastic tetraparesis. Eur J Hum Genet 2021; 29:1359-1368. [PMID: 34075211 PMCID: PMC8440635 DOI: 10.1038/s41431-021-00900-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/25/2021] [Accepted: 04/15/2021] [Indexed: 11/09/2022] Open
Abstract
The genetic etiology of intellectual disability remains elusive in almost half of all affected individuals. Within the Solve-RD consortium, systematic re-analysis of whole exome sequencing (WES) data from unresolved cases with (syndromic) intellectual disability (n = 1,472 probands) was performed. This re-analysis included variant calling of mitochondrial DNA (mtDNA) variants, although mtDNA is not specifically targeted in WES. We identified a functionally relevant mtDNA variant in MT-TL1 (NC_012920.1:m.3291T > C; NC_012920.1:n.62T > C), at a heteroplasmy level of 22% in whole blood, in a 23-year-old male with severe intellectual disability, epilepsy, episodic headaches with emesis, spastic tetraparesis, brain abnormalities, and feeding difficulties. Targeted validation in blood and urine supported pathogenicity, with heteroplasmy levels of 23% and 58% in index, and 4% and 17% in mother, respectively. Interestingly, not all phenotypic features observed in the index have been previously linked to this MT-TL1 variant, suggesting either broadening of the m.3291T > C-associated phenotype, or presence of a co-occurring disorder. Hence, our case highlights the importance of underappreciated mtDNA variants identifiable from WES data, especially for cases with atypical mitochondrial phenotypes and their relatives in the maternal line.
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Affiliation(s)
- Elke de Boer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Charlotte W Ockeloen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Leslie Matalonga
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, John Van Geest Cambridge Centre for Brain Repair, Cambridge, UK
| | - Richard J Rodenburg
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marieke J H Coenen
- Department of Human Genetics, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mirian Janssen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dylan Henssen
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter Steyaert
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ida Paramonov
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Aurélien Trimouille
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
- MRGM, Maladies Rares: Génétique et Métabolisme, lNSERM U1211, Université de Bordeaux, Bordeaux, France
| | - Tjitske Kleefstra
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alain Verloes
- Département de Génétique, APHP Robert DEBRE University Hospital and INSERM U1141, Paris, France
| | - Lisenka E L M Vissers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Dineen EH, Torkamani A, Muse ED. Kickboxing a cardiomyopathy: mitochondrial sequencing provides answer for young athlete and her family. BMJ Case Rep 2021; 14:e237592. [PMID: 33431453 PMCID: PMC7802639 DOI: 10.1136/bcr-2020-237592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2020] [Indexed: 01/13/2023] Open
Abstract
Mitochondrial diseases are rare, often go undiagnosed and can lead to devastating cascades of multisystem organ dysfunction. This report of a young woman with hearing loss and gestational diabetes illustrates a novel presentation of a cardiomyopathy caused by a previously described mutation in a mitochondrial gene, MT-TL1. She initially had biventricular heart dysfunction and ventricular arrhythmia that ultimately recovered with beta blockade and time. She continues to participate in sport without decline. It is important to keep mitochondrial diseases in the differential diagnosis and understand the testing and management strategies in order to provide the best patient care.
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Affiliation(s)
- Elizabeth H Dineen
- Department of Cardiology, Prebys Cardiovascular Institute, Scripps Clinic, La Jolla, California, USA
| | - Ali Torkamani
- Scripps Research Translational Institute, La Jolla, California, USA
| | - Evan D Muse
- Department of Cardiology, Prebys Cardiovascular Institute, Scripps Clinic, La Jolla, California, USA
- Scripps Research Translational Institute, La Jolla, California, USA
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5
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Kim M, van Hoof A. Suppressors of mRNA Decapping Defects Restore Growth Without Major Effects on mRNA Decay Rates or Abundance. Genetics 2020; 216:1051-1069. [PMID: 32998951 PMCID: PMC7768250 DOI: 10.1534/genetics.120.303641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/28/2020] [Indexed: 01/09/2023] Open
Abstract
Faithful degradation of mRNAs is a critical step in gene expression, and eukaryotes share a major conserved mRNA decay pathway. In this major pathway, the two rate-determining steps in mRNA degradation are the initial gradual removal of the poly(A) tail, followed by removal of the cap structure. Removal of the cap structure is carried out by the decapping enzyme, containing the Dcp2 catalytic subunit. Although the mechanism and regulation of mRNA decay is well understood, the consequences of defects in mRNA degradation are less clear. Dcp2 has been reported as either essential or nonessential. Here, we clarify that Dcp2 is not absolutely required for spore germination and extremely slow growth, but in practical terms it is impossible to continuously culture dcp2∆ under laboratory conditions without suppressors arising. We show that null mutations in at least three different genes are each sufficient to restore growth to a dcp2∆, of which kap123∆ and tl(gag)g∆ appear the most specific. We show that kap123∆ and tl(gag)g∆ suppress dcp2 by mechanisms that are different from each other and from previously isolated dcp2 suppressors. The suppression mechanism for tL(GAG)G is determined by the unique GAG anticodon of this tRNA, and thus likely by translation of some CUC or CUU codons. Unlike previously reported suppressors of decapping defects, these suppressors do not detectably restore decapping or mRNA decay to normal rates, but instead allow survival while only modestly affecting RNA homeostasis. These results provide important new insight into the importance of decapping, resolve previously conflicting publications about the essentiality of DCP2, provide the first phenotype for a tl(gag)g mutant, and show that multiple distinct mechanisms can bypass Dcp2 requirement.
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Affiliation(s)
- Minseon Kim
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ambro van Hoof
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
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6
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O'Donnell L, Blakely EL, Baty K, Alexander M, Bogdanova-Mihaylova P, Craig J, Walsh R, Brett F, Taylor RW, Murphy SM. Chronic Progressive External Ophthalmoplegia due to a Rare de novo m.12334G>A MT-TL2 Mitochondrial DNA Variant1. J Neuromuscul Dis 2020; 7:355-360. [PMID: 32310184 DOI: 10.3233/jnd-200486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We describe a patient with chronic progressive external ophthalmoplegia (CPEO) due to a rare mitochondrial genetic variant. Muscle biopsy revealed numerous cytochrome c oxidase (COX)-deficient fibres, prompting sequencing of the entire mitochondrial genome in muscle which revealed a rare m.12334G>A variant in the mitochondrial (mt-) tRNALeu(CUN)(MT-TL2) gene. Analysis of several tissues showed this to be a de novo mutational event. Single fibre studies confirmed the segregation of high m.12334G>A heteroplasmy levels with the COX histochemical defect, confirming pathogenicity of the m.12334G>A MT-TL2 variant. This case illustrates the importance of pursuing molecular genetic analysis in clinically-affected tissues when mitochondrial disease is suspected.
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Affiliation(s)
- Luke O'Donnell
- Department of Neurology, Tallaght University Hospital, Tallaght, Dublin, Ireland
| | - Emma L Blakely
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Mitochondrial Diagnostic Laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Karen Baty
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Mitochondrial Diagnostic Laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Michael Alexander
- Department of Neurophysiology, Tallaght University Hospital, Tallaght, Dublin, Ireland
- Academic Unit of Neurology, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | | | - John Craig
- Department of Neurology, Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Ronan Walsh
- Department of Neurology, Hermitage Medical Clinic, Dublin, Ireland
| | - Francesca Brett
- Department of Neuropathology, Beaumont Hospital, Dublin, Ireland
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Mitochondrial Diagnostic Laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Sinead M Murphy
- Department of Neurology, Tallaght University Hospital, Tallaght, Dublin, Ireland
- Academic Unit of Neurology, Trinity College Dublin, The University of Dublin, Dublin, Ireland
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7
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Sanz MA, Almela EG, García-Moreno M, Marina AI, Carrasco L. A viral RNA motif involved in signaling the initiation of translation on non-AUG codons. RNA 2019; 25:431-452. [PMID: 30659060 PMCID: PMC6426287 DOI: 10.1261/rna.068858.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Noncanonical translation, and particularly initiation on non-AUG codons, are frequently used by viral and cellular mRNAs during virus infection and disease. The Sindbis virus (SINV) subgenomic mRNA (sgRNA) constitutes a unique model system to analyze the translation of a capped viral mRNA without the participation of several initiation factors. Moreover, sgRNA can initiate translation even when the AUG initiation codon is replaced by other codons. Using SINV replicons, we examined the efficacy of different codons in place of AUG to direct the synthesis of the SINV capsid protein. The substitution of AUG by CUG was particularly efficient in promoting the incorporation of leucine or methionine in similar percentages at the amino terminus of the capsid protein. Additionally, valine could initiate translation when the AUG is replaced by GUG. The ability of sgRNA to initiate translation on non-AUG codons was dependent on the integrity of a downstream stable hairpin (DSH) structure located in the coding region. The structural requirements of this hairpin to signal the initiation site on the sgRNA were examined in detail. Of interest, a virus bearing CUG in place of AUG in the sgRNA was able to infect cells and synthesize significant amounts of capsid protein. This virus infects the human haploid cell line HAP1 and the double knockout variant that lacks eIF2A and eIF2D. Collectively, these findings indicate that leucine-tRNA or valine-tRNA can participate in the initiation of translation of sgRNA by a mechanism dependent on the DSH. This mechanism does not involve the action of eIF2, eIF2A, or eIF2D.
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MESH Headings
- Capsid Proteins/biosynthesis
- Capsid Proteins/genetics
- Cell Line, Tumor
- Codon, Initiator/genetics
- Codon, Initiator/metabolism
- Eukaryotic Initiation Factor-2/deficiency
- Eukaryotic Initiation Factor-2/genetics
- Fibroblasts/metabolism
- Fibroblasts/virology
- Gene Expression Regulation
- Haploidy
- Host-Pathogen Interactions/genetics
- Humans
- Inverted Repeat Sequences
- Leucine/genetics
- Leucine/metabolism
- Methionine/genetics
- Methionine/metabolism
- Nucleic Acid Conformation
- Protein Biosynthesis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Transfer, Leu/genetics
- RNA, Transfer, Leu/metabolism
- RNA, Transfer, Val/genetics
- RNA, Transfer, Val/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Replicon
- Signal Transduction/genetics
- Sindbis Virus/genetics
- Sindbis Virus/metabolism
- Valine/genetics
- Valine/metabolism
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Affiliation(s)
- Miguel Angel Sanz
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Esther González Almela
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Manuel García-Moreno
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Ana Isabel Marina
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
| | - Luis Carrasco
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
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8
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Su T, Grady JP, Afshar S, McDonald SAC, Taylor RW, Turnbull DM, Greaves LC. Inherited pathogenic mitochondrial DNA mutations and gastrointestinal stem cell populations. J Pathol 2018; 246:427-432. [PMID: 30146801 PMCID: PMC6282723 DOI: 10.1002/path.5156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/02/2018] [Accepted: 08/12/2018] [Indexed: 01/07/2023]
Abstract
Inherited mitochondrial DNA (mtDNA) mutations cause mitochondrial disease, but mtDNA mutations also occur somatically and accumulate during ageing. Studies have shown that the mutation load of some inherited mtDNA mutations decreases over time in blood, suggesting selection against the mutation. However, it is unknown whether such selection occurs in other mitotic tissues, and where it occurs within the tissue. Gastrointestinal epithelium is a canonical mitotic tissue rapidly renewed by stem cells. Intestinal crypts (epithelium) undergo monoclonal conversion with a single stem cell taking over the niche and producing progeny. We show: (1) that there is a significantly lower mtDNA mutation load in the mitotic epithelium of the gastrointestinal tract when compared to the smooth muscle in the same tissue in patients with the pathogenic m.3243A>G and m.8344A>G mutations; (2) that there is considerable variation seen in individual crypts, suggesting changes in the stem cell population; (3) that this lower mutation load is reflected in the absence of a defect in oxidative phosphorylation in the epithelium. This suggests that there is selection against inherited mtDNA mutations in the gastrointestinal stem cells that is in marked contrast to the somatic mtDNA mutations that accumulate with age in epithelial stem cells leading to a biochemical defect. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Tianhong Su
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, Newcastle UniversityNewcastle upon TyneUK
| | - John P Grady
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, Newcastle UniversityNewcastle upon TyneUK
| | - Sorena Afshar
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and VitalityNewcastle upon TyneUK
| | - Stuart AC McDonald
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of LondonLondonUK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, Newcastle UniversityNewcastle upon TyneUK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, Newcastle UniversityNewcastle upon TyneUK
- LLHW Centre for Ageing and Vitality, Newcastle University Institute for Ageing, The Medical SchoolNewcastle upon TyneUK
| | - Laura C Greaves
- Wellcome Centre for Mitochondrial ResearchInstitute of Neuroscience, Newcastle UniversityNewcastle upon TyneUK
- LLHW Centre for Ageing and Vitality, Newcastle University Institute for Ageing, The Medical SchoolNewcastle upon TyneUK
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9
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Mühlhausen S, Schmitt HD, Pan KT, Plessmann U, Urlaub H, Hurst LD, Kollmar M. Endogenous Stochastic Decoding of the CUG Codon by Competing Ser- and Leu-tRNAs in Ascoidea asiatica. Curr Biol 2018; 28:2046-2057.e5. [PMID: 29910077 PMCID: PMC6041473 DOI: 10.1016/j.cub.2018.04.085] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/22/2018] [Accepted: 04/24/2018] [Indexed: 12/24/2022]
Abstract
Although the “universal” genetic code is now known not to be universal, and stop codons can have multiple meanings, one regularity remains, namely that for a given sense codon there is a unique translation. Examining CUG usage in yeasts that have transferred CUG away from leucine, we here report the first example of dual coding: Ascoidea asiatica stochastically encodes CUG as both serine and leucine in approximately equal proportions. This is deleterious, as evidenced by CUG codons being rare, never at conserved serine or leucine residues, and predominantly in lowly expressed genes. Related yeasts solve the problem by loss of function of one of the two tRNAs. This dual coding is consistent with the tRNA-loss-driven codon reassignment hypothesis, and provides a unique example of a proteome that cannot be deterministically predicted. Video Abstract
Ascoidea asiatica stochastically encodes CUG as leucine and serine It is the only known example of a proteome with non-deterministic features Stochastic encoding is caused by competing tRNALeu(CAG) and tRNASer(CAG) A. asiatica copes with stochastic encoding by avoiding CUG at key positions
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Affiliation(s)
- Stefanie Mühlhausen
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Hans Dieter Schmitt
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kuan-Ting Pan
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Uwe Plessmann
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Bioanalytics Group, Department of Clinical Chemistry, University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen, Germany
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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10
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Chichagova V, Hallam D, Collin J, Buskin A, Saretzki G, Armstrong L, Yu-Wai-Man P, Lako M, Steel DH. Human iPSC disease modelling reveals functional and structural defects in retinal pigment epithelial cells harbouring the m.3243A > G mitochondrial DNA mutation. Sci Rep 2017; 7:12320. [PMID: 28951556 PMCID: PMC5615077 DOI: 10.1038/s41598-017-12396-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 09/08/2017] [Indexed: 01/19/2023] Open
Abstract
The m.3243A > G mitochondrial DNA mutation was originally described in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The phenotypic spectrum of the m.3243A > G mutation has since expanded to include a spectrum of neuromuscular and ocular manifestations, including reduced vision with retinal degeneration, the underlying mechanism of which remains unclear. We used dermal fibroblasts, from patients with retinal pathology secondary to the m.3243A > G mutation to generate heteroplasmic induced pluripotent stem cell (hiPSC) clones. RPE cells differentiated from these hiPSCs contained morphologically abnormal mitochondria and melanosomes, and exhibited marked functional defects in phagocytosis of photoreceptor outer segments. These findings have striking similarities to the pathological abnormalities reported in RPE cells studied from post-mortem tissues of affected m.3243A > G mutation carriers. Overall, our results indicate that RPE cells carrying the m.3243A > G mutation have a reduced ability to perform the critical physiological function of phagocytosis. Aberrant melanosomal morphology may potentially have consequences on the ability of the cells to perform another important protective function, namely absorption of stray light. Our in vitro cell model could prove a powerful tool to further dissect the complex pathophysiological mechanisms that underlie the tissue specificity of the m.3243A > G mutation, and importantly, allow the future testing of novel therapeutic agents.
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Affiliation(s)
- Valeria Chichagova
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Joseph Collin
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Adriana Buskin
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Gabriele Saretzki
- Institute for Cell and Molecular Biosciences and The Ageing Biology Centre, Campus for Ageing and Vitality, Newcastle University, NE4 5PL, United Kingdom
| | - Lyle Armstrong
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, United Kingdom
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, United Kingdom
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, United Kingdom
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom.
| | - David H Steel
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom.
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11
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Zhu K, Li S, Chen H, Wang Y, Yu M, Wang H, Zhao W, Cao Y. Late onset MELAS with m.3243A > G mutation and its association with aneurysm formation. Metab Brain Dis 2017; 32:1069-1072. [PMID: 28321601 DOI: 10.1007/s11011-017-9989-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/03/2017] [Indexed: 10/19/2022]
Abstract
We reported a 53-year-old with late-onset mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) accompanied by aneurysm and large vessel dilations. Most studies have focused on microangiopathy causing stroke-like episodes. We report a case to describe large vessel involvement in clinical considerations, and possible mechanisms of aneurysm formation. We recommended regular angiographic examination for patients with MELAS.
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Affiliation(s)
- Kun Zhu
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China
- The 96th Class, 7-Year Program, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, China
| | - Shuang Li
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China
| | - Huan Chen
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China
| | - Yao Wang
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China
| | - Miao Yu
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China
- The 97th Class, 7-Year Program, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, China
| | - Hongyan Wang
- Department of Cadre, The Central Hospital of Jiamusi City, No. 256 Zhongshan Road, Xiangyang District, Jiamusi, Heilongjiang, 154002, China
| | - Weijie Zhao
- Department of Neurology, Capital Medical University Affiliated Beijing Friendship Hospital, No. 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Yunpeng Cao
- Department of Neurology, First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, Liaoning, 110001, China.
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12
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Zhang Y, Du X, Geng X, Chu C, Lu H, Shen Y, Chen R, Fang P, Feng Y, Zhang X, Chen Y, Zhou Y, Wang C, Jia W. Rapid Detection of the mt3243A > G Mutation Using Urine Sediment in Elderly Chinese Type 2 Diabetic Patients. J Diabetes Res 2017; 2017:4683857. [PMID: 28713835 PMCID: PMC5497653 DOI: 10.1155/2017/4683857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/15/2017] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE In this study, we aimed to identify mt3243A > G mutation carriers in a group of Chinese elderly type 2 diabetic patients by a rapid and noninvasive diagnostic system. METHODS DNA was extracted from blood, saliva, and urine sediment samples. The mutation screening and quantitation of heteroplasmy were performed by high-resolution melting (HRM) curve and pyrosequencing, respectively. Patients with mt3243A > G mutation underwent a detailed audiometric, ophthalmologic, neurological, and cardiac examination. RESULTS Two patients (2/1041) carrying the mt3243A > G mutation were detected among all type 2 diabetic patients. In patient 1, the heteroplasmy was 0.8%, 2.8%, and 14.7% in peripheral blood leukocytes, saliva, and urine sediment, respectively. In patient 2, the heteroplasmy was 5.3%, 8.4%, and 37.7% in peripheral blood leukocytes, saliva, and urine sediment, respectively. Both of the two patients showed hearing impairment. Abnormal ophthalmologic conditions and hyperintensity on T2-weighted magnetic resonance images were showed in patient 1. CONCLUSION The occurrence of mt3243 A > G mutation was 0.2% in Chinese elderly type 2 diabetic patients. Moreover, detection of mt3243 A > G mutation in urine sediment with high-resolution melting (HRM) curve and pyrosequencing is feasible in molecular genetic diagnosis.
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Affiliation(s)
- Yinan Zhang
- The Metabolic Diseases Biobank, Center for Translational Medicine, Shanghai Key Laboratory of Diabetes, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xiujuan Du
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xinqian Geng
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Chen Chu
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Huijuan Lu
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Yixie Shen
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Ruihua Chen
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Pingyan Fang
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Yanmei Feng
- Department of Otolaryngology Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xiaojie Zhang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Yan Chen
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Yanping Zhou
- Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai 200080, China
| | - Congrong Wang
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
- *Congrong Wang: and
| | - Weiping Jia
- Department of Endocrinology and Metabolism, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
- *Weiping Jia:
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Dvorakova V, Kolarova H, Magner M, Tesarova M, Hansikova H, Zeman J, Honzik T. The phenotypic spectrum of fifty Czech m.3243A>G carriers. Mol Genet Metab 2016; 118:288-95. [PMID: 27296531 DOI: 10.1016/j.ymgme.2016.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/04/2016] [Accepted: 06/05/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Mitochondrial myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes syndrome (MELAS) is a common mitochondrial disorder with varying multisystemic clinical manifestation. We present a comprehensive clinical picture of 50 Czech m.3243A>G carriers with emphasis on the sequence of symptoms in symptomatic patients. RESULTS Symptoms developed in 33 patients (66%) and 17 carriers remained unaffected (34%). The age of onset varied from 1month to 47years of age, with juvenile presentation occurring in 53% of patients. Myopathy was the most common presenting symptom (18%), followed by CPEO/ptosis and hearing loss, with the latter also being the most common second symptom. Stroke-like episodes (SLE) occurred in fourteen patients, although never as a first symptom, and were frequently preceded by migraines (58%). Rhabdomyolysis developed in two patients. The second symptom appeared 5.0±8.3years (range 0-28years) after the first, and the interval between the second and third symptom was 2.0±6.0years (range 0-21years). Four of our patients remained monosymptomatic up to 12years of follow-up. The sequence of symptoms according to their time of manifestation was migraines, myopathy, seizures, CPEO/ptosis, SLE, hearing loss, and diabetes mellitus. The average age at death was 32.4±17.7years (range 9-60years) in the juvenile form and 44.0±12.7years (range 35-53years) in the adult form. Some patients with SLE harboured very low heteroplasmy levels in various tissues. No threshold for any organ dysfunction could be determined based on these levels. CONCLUSIONS Sufficient knowledge of the timeline of the natural course of MELAS syndrome may improve the prediction and management of symptoms in patients with this mitochondrial disease.
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Affiliation(s)
- V Dvorakova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - H Kolarova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - M Magner
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - M Tesarova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - H Hansikova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - J Zeman
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - T Honzik
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic.
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14
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Modrzejewska M, Chrzanowska M, Modrzejewska A, Romanowska H, Ostrowska I, Giżewska M. [Ocular findings in MELAS syndrome – a case report]. Klin Oczna 2016; 118:301-307. [PMID: 29911364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a case of a child with MELAS syndrome (mitochondrial encephalo-myopathy with lactic acidosis and stroke-like episodes), discussing clinical manifestation, ocular findings and diagnostic challenges. Predominant ocular symptom was a transient complete visual loss, while the predominant ocular sign was a visual field defect. The diagnosia was based on clinical manifestation, laboratory tests, brain scans and genetic testing which confirmed the pathognomonic mutation in the MTTL1 gene encoding the mitochondrial tRNA for leucine 3243> G. Ocular examination demonstrated decreased visual acuity (with bilateral best corrected visual acuity of .1). Periodical, transient visual loss and visual field defects were clinically predominant. Specialist investigations were carried out, which demonstrated homonymous hemianopia (kinetic perimetry), bilateral partial optic nerve atrophy (RetCam). Funduscopy and electrophysiology mfERG study did not confirm features of retinitis pigmentosa. The brain scans revealed numerous small cortical ischemic lesions within the frontal, parietal and temporal lobes, post-stroke focal areas within the occipital lobes and diffuse calcifications of the basal ganglia. During several years of follow-up, visual field defects showed progressive concentric narrowing. The patient received a long-term treatment with arginine, coenzyme Q and vitamin D, both oral and intravenous, but no beneficial effect for the improvement of ophthalmic condition was observed. As it is the case in severe MELAS syndrome, the course of disease was fatal and the patientdied at the age of 14.
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15
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Finsterer J, Frank M, Mishra A. Genetic background and phenotypic heterogeneity of MELAS and maternally inherited diabetes and deafness. Int J Clin Exp Pathol 2015; 8:15439-15441. [PMID: 26823911 PMCID: PMC4713697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/23/2015] [Indexed: 06/05/2023]
Affiliation(s)
| | - Marlies Frank
- First Medical Department, Krankenanstalt RudolfstiftungVienna, Austria, Europe
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16
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El-Hattab AW, Adesina AM, Jones J, Scaglia F. MELAS syndrome: Clinical manifestations, pathogenesis, and treatment options. Mol Genet Metab 2015; 116:4-12. [PMID: 26095523 DOI: 10.1016/j.ymgme.2015.06.004] [Citation(s) in RCA: 349] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/14/2015] [Accepted: 06/14/2015] [Indexed: 12/13/2022]
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is one of the most frequent maternally inherited mitochondrial disorders. MELAS syndrome is a multi-organ disease with broad manifestations including stroke-like episodes, dementia, epilepsy, lactic acidemia, myopathy, recurrent headaches, hearing impairment, diabetes, and short stature. The most common mutation associated with MELAS syndrome is the m.3243A>G mutation in the MT-TL1 gene encoding the mitochondrial tRNA(Leu(UUR)). The m.3243A>G mutation results in impaired mitochondrial translation and protein synthesis including the mitochondrial electron transport chain complex subunits leading to impaired mitochondrial energy production. The inability of dysfunctional mitochondria to generate sufficient energy to meet the needs of various organs results in the multi-organ dysfunction observed in MELAS syndrome. Energy deficiency can also stimulate mitochondrial proliferation in the smooth muscle and endothelial cells of small blood vessels leading to angiopathy and impaired blood perfusion in the microvasculature of several organs. These events will contribute to the complications observed in MELAS syndrome particularly the stroke-like episodes. In addition, nitric oxide deficiency occurs in MELAS syndrome and can contribute to its complications. There is no specific consensus approach for treating MELAS syndrome. Management is largely symptomatic and should involve a multidisciplinary team. Unblinded studies showed that l-arginine therapy improves stroke-like episode symptoms and decreases the frequency and severity of these episodes. Additionally, carnitine and coenzyme Q10 are commonly used in MELAS syndrome without proven efficacy.
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Adekunle M Adesina
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Jeremy Jones
- Singleton Department of Radiology, Texas Children's Hospital, Houston, TX, USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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17
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Kaasalainen U, Olsson S, Rikkinen J. Evolution of the tRNALeu (UAA) Intron and Congruence of Genetic Markers in Lichen-Symbiotic Nostoc. PLoS One 2015; 10:e0131223. [PMID: 26098760 PMCID: PMC4476775 DOI: 10.1371/journal.pone.0131223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/29/2015] [Indexed: 01/16/2023] Open
Abstract
The group I intron interrupting the tRNALeu UAA gene (trnL) is present in most cyanobacterial genomes as well as in the plastids of many eukaryotic algae and all green plants. In lichen symbiotic Nostoc, the P6b stem-loop of trnL intron always involves one of two different repeat motifs, either Class I or Class II, both with unresolved evolutionary histories. Here we attempt to resolve the complex evolution of the two different trnL P6b region types. Our analysis indicates that the Class II repeat motif most likely appeared first and that independent and unidirectional shifts to the Class I motif have since taken place repeatedly. In addition, we compare our results with those obtained with other genetic markers and find strong evidence of recombination in the 16S rRNA gene, a marker widely used in phylogenetic studies on Bacteria. The congruence of the different genetic markers is successfully evaluated with the recently published software Saguaro, which has not previously been utilized in comparable studies.
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Affiliation(s)
- Ulla Kaasalainen
- Department of Geobiology, University of Göttingen, Göttingen, Germany
- * E-mail:
| | - Sanna Olsson
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jouko Rikkinen
- Department of Biosciences, University of Helsinki, Helsinki, Finland
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18
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Li W, Zhang W, Li F, Wang C. Mitochondrial genetic analysis in a Chinese family suffering from both mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes and diabetes. Int J Clin Exp Pathol 2015; 8:7022-7027. [PMID: 26261593 PMCID: PMC4525927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/20/2015] [Indexed: 06/04/2023]
Abstract
To investigate the mitochondrial mutations in patients suffering from both mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) and maternally inherited diabetes. MELAS was confirmed by muscle biopsy performed from the biceps muscle of the proband. Mitochondrial DNA (mtDNA) was isolated from peripheral blood mononuclear cells. The significant mtDNA loci of other 14 family members were further detected according to the sequencing results of the proband. Direct sequencing of PCR products was used to identify the mitochondrial mutations. The proband (III 1) and her brother (III 3) both harbored the tRNALeu (UUR) A3243G mutation, with heteroplasmic levels of 50% and 33% respectively. Moreover, another two mitochondrial variants, A8860G and A15326G, were also detected in the samples of all the family members. MELAS and diabetes can coexist in one patient, and the main cause for these diseases is the tRNALeu (UUR) A3243G mutation. However, other gene variants may contribute to its pathogenesis. This case also supports the concept that both syndromes can be regarded as two phenotypes of the same disease.
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Affiliation(s)
- Weiwei Li
- Department of Endocrinology, Qianfoshan Hospital, Shandong University 66 Jingshi Road, Jinan 250014, China
| | - Wei Zhang
- Department of Endocrinology, Qianfoshan Hospital, Shandong University 66 Jingshi Road, Jinan 250014, China
| | - Fang Li
- Department of Endocrinology, Qianfoshan Hospital, Shandong University 66 Jingshi Road, Jinan 250014, China
| | - Cailing Wang
- Department of Endocrinology, Qianfoshan Hospital, Shandong University 66 Jingshi Road, Jinan 250014, China
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Abstract
Population genetics of invading pests can be informative for understanding their ecology. In this study, we investigated population genetics of the invasive alfalfa weevil Hypera postica in Fukuoka Prefecture, Japan. We analyzed mitochondrial tRNALeu-COII, nuclear EF-1α gene fragments, and Wolbachia infection in relation to three leguminous host plants: Vicia angustifolia, Vicia villosa, and a new host Astragalus sinicus cultivated as a honey source and green manure crop. A parsimony network generated from mitochondrial gene sequences uncovered two major haplotypic groups, Western and Egyptian. In contrast to reported Wolbachia infection of the Western strain in the United States, none of our analyzed individuals were infected. The absence of Wolbachia may contribute to the stable coexistence of mitochondrial strains through inter-strain reproductive compatibility. Hypera postica genetic variants for the mitochondrial and nuclear genes were associated neither with host plant species nor with two geographic regions (Hisayama and Kama) within Fukuoka. Mitochondrial haplogroups were incongruent with nuclear genetic variants. Genetic diversity at the nuclear locus was the highest for the populations feeding on V. angustifolia. The nuclear data for A. sinicus-feeding populations indicated past sudden population growth and extended Bayesian skyline plot analysis based on the mitochondrial and nuclear data showed that the growth of A. sinicus-feeding population took place within the past 1000 years. These results suggest a shorter history of A. sinicus as a host plant compared with V. angustifolia and a recent rapid growth of H. postica population using the new host A. sinicus.
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Affiliation(s)
- S-I Iwase
- Institute of Biological Control, Faculty of Agriculture,Kyushu University,Fukuoka 812-8581,Japan
| | - K Nakahira
- Institute of Biological Control, Faculty of Agriculture,Kyushu University,Fukuoka 812-8581,Japan
| | - M Tuda
- Institute of Biological Control, Faculty of Agriculture,Kyushu University,Fukuoka 812-8581,Japan
| | - K Kagoshima
- Institute of Biological Control, Faculty of Agriculture,Kyushu University,Fukuoka 812-8581,Japan
| | - M Takagi
- Institute of Biological Control, Faculty of Agriculture,Kyushu University,Fukuoka 812-8581,Japan
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Fung AWS, Leung CCY, Fahlman RP. The determination of tRNALeu recognition nucleotides for Escherichia coli L/F transferase. RNA 2014; 20:1210-1222. [PMID: 24935875 PMCID: PMC4105747 DOI: 10.1261/rna.044529.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/28/2014] [Indexed: 06/03/2023]
Abstract
Escherichia coli leucyl/phenylalanyl-tRNA protein transferase catalyzes the tRNA-dependent post-translational addition of amino acids onto the N-terminus of a protein polypeptide substrate. Based on biochemical and structural studies, the current tRNA recognition model by L/F transferase involves the identity of the 3' aminoacyl adenosine and the sequence-independent docking of the D-stem of an aminoacyl-tRNA to the positively charged cluster on L/F transferase. However, this model does not explain the isoacceptor preference observed 40 yr ago. Using in vitro-transcribed tRNA and quantitative MALDI-ToF MS enzyme activity assays, we have confirmed that, indeed, there is a strong preference for the most abundant leucyl-tRNA, tRNA(Leu) (anticodon 5'-CAG-3') isoacceptor for L/F transferase activity. We further investigate the molecular mechanism for this preference using hybrid tRNA constructs. We identified two independent sequence elements in the acceptor stem of tRNA(Leu) (CAG)-a G₃:C₇₀ base pair and a set of 4 nt (C₇₂, A₄:U₆₉, C₆₈)-that are important for the optimal binding and catalysis by L/F transferase. This maps a more specific, sequence-dependent tRNA recognition model of L/F transferase than previously proposed.
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Affiliation(s)
- Angela Wai Shan Fung
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | | - Richard Peter Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7 Department of Oncology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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Leszczynska G, Leonczak P, Wozniak K, Malkiewicz A. Chemical synthesis of the 5-taurinomethyl(-2-thio)uridine modified anticodon arm of the human mitochondrial tRNA(Leu(UUR)) and tRNA(Lys). RNA 2014; 20:938-947. [PMID: 24757169 PMCID: PMC4024646 DOI: 10.1261/rna.044412.114] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
5-Taurinomethyluridine (τm(5)U) and 5-taurinomethyl-2-thiouridine (τm(5)s(2)U) are located at the wobble position of human mitochondrial (hmt) tRNA(Leu(UUR)) and tRNA(Lys), respectively. Both hypermodified units restrict decoding of the third codon letter to A and G. Pathogenic mutations in the genes encoding hmt-tRNA(Leu(UUR)) and hmt-tRNA(Lys) are responsible for the loss of the discussed modifications and, as a consequence, for the occurrence of severe mitochondrial dysfunctions (MELAS, MERRF). Synthetic oligoribonucleotides bearing modified nucleosides are a versatile tool for studying mechanisms of genetic message translation and accompanying pathologies at nucleoside resolution. In this paper, we present site-specific chemical incorporation of τm(5)U and τm(5)s(2)U into 17-mers related to the sequence of the anticodon arms hmt-tRNA(Leu(UUR)) and hmt-tRNA(Lys), respectively employing phosphoramidite chemistry on CPG support. Selected protecting groups for the sulfonic acid (4-(tert-butyldiphenylsilanyloxy)-2,2-dimethylbutyl) and the exoamine function (-C(O)CF3) are compatible with the blockage of the canonical monomeric units. The synthesis of τm(5)s(2)U-modified RNA fragment was performed under conditions eliminating the formation of side products of 2-thiocarbonyl group oxidation and/or oxidative desulphurization. The structure of the final oligomers was confirmed by mass spectroscopy and enzymatic cleavage data.
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Amornvit J, Pasutharnchat N, Pachinburavan M, Jongpiputvanich S, Joyjinda Y. Fulminant respiratory muscle paralysis, an expanding clinical spectrum of mitochondrial A3243G tRNALeu mutation. J Med Assoc Thai 2014; 97:467-472. [PMID: 24964690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mitochondrial disease is a group of rare disorders, caused by mitochondrial dysfunction. They are usually the result of mutations of either mitochondrial DNA or nuclear DNA. A3243G transition in the tRNALeu is one the most frequent mutations of the mitochondrial DNA. Phenotypic expression of this mutation varies. The most well-recognized phenotype is Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Isolated myopathy with respiratory muscle weakness in this mutation has been rarely documented. The authors reported a 20-year-old Asian female presenting with a fulminant hypoventilatory respiratory failure with mild weakness of the limbs. Electrophysiologic study showed evidences of myopathy. Restrictive physiology of the lungs was demonstrated by pulmonary function test. Subsarcolemmal accumulation of mitochondria was demonstrated by Gomori trichrome and succinate dehydrogenase stains. Genetic study revealed the A3243G mutation in mitochondrial DNA in peripheral blood Isolated mitochondrial myopathy severely affecting respiratory muscles may be considered as an uncommon clinical spectrum of A3243G mitochondrial disease.
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Abstract
We report the case of a 19-year-old Chinese female harboring the m.3291T>C mutation in the MT-TL1 gene encoding the mitochondrial transfer RNA for leucine. She presented with a complex phenotype characterized by progressive cerebellar ataxia, frequent myoclonus seizures, recurrent stroke-like episodes, migraine-like headaches with nausea and vomiting, and elevated resting lactate blood level. It is known that the myoclonus epilepsy with ragged-red fibers (MERRF) is characterized by cerebellar ataxia and myoclonus epilepsy, while that the mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is characterized by recurrent stroke-like episodes, migraine-like headaches, and elevated resting lactate blood level. So the patient's clinical manifestations suggest the presence of a MERRF/MELAS overlap syndrome. Muscle biopsy of the patient showed the presence of numerous scattered ragged-red fibers, some cytochrome c oxidase-deficient fibers, and several strongly succinate dehygrogenase-reactive vessels, suggestive of a mitochondrial disorder. Direct sequencing of the complete mitochondrial genome of the proband revealed no mutations other than the T-to-C transition at nucleotide position 3291. Restriction fragment length polymorphism analysis of the proband and her family revealed maternal inheritance of the mutation in a heteroplasmic manner. The analysis of aerobic respiration and glycolysis demonstrated that the fibroblasts from the patient had mitochondrial dysfunction. Our results suggest that the m.3291T>C is pathogenic. This study is the first to describe the m.3291T>C mutation in association with the MERRF/MELAS overlap syndrome.
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Affiliation(s)
- Kaiming Liu
- Laboratory of Neuromuscular Disorders and Department of Neurology, Qilu Hospital, Shandong University, Jinan, 250012, China
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24
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Perli E, Giordano C, Pisano A, Montanari A, Campese AF, Reyes A, Ghezzi D, Nasca A, Tuppen HA, Orlandi M, Di Micco P, Poser E, Taylor RW, Colotti G, Francisci S, Morea V, Frontali L, Zeviani M, d'Amati G. The isolated carboxy-terminal domain of human mitochondrial leucyl-tRNA synthetase rescues the pathological phenotype of mitochondrial tRNA mutations in human cells. EMBO Mol Med 2014; 6:169-82. [PMID: 24413190 PMCID: PMC3927953 DOI: 10.1002/emmm.201303198] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/16/2013] [Accepted: 10/17/2013] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial (mt) diseases are multisystem disorders due to mutations in nuclear or mtDNA genes. Among the latter, more than 50% are located in transfer RNA (tRNA) genes and are responsible for a wide range of syndromes, for which no effective treatment is available at present. We show that three human mt aminoacyl-tRNA syntethases, namely leucyl-, valyl-, and isoleucyl-tRNA synthetase are able to improve both viability and bioenergetic proficiency of human transmitochondrial cybrid cells carrying pathogenic mutations in the mt-tRNA(Ile) gene. Importantly, we further demonstrate that the carboxy-terminal domain of human mt leucyl-tRNA synthetase is both necessary and sufficient to improve the pathologic phenotype associated either with these "mild" mutations or with the "severe" m.3243A>G mutation in the mt-tRNA(L)(eu(UUR)) gene. Furthermore, we provide evidence that this small, non-catalytic domain is able to directly and specifically interact in vitro with human mt-tRNA(Leu(UUR)) with high affinity and stability and, with lower affinity, with mt-tRNA(Ile). Taken together, our results sustain the hypothesis that the carboxy-terminal domain of human mt leucyl-tRNA synthetase can be used to correct mt dysfunctions caused by mt-tRNA mutations.
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Affiliation(s)
- Elena Perli
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
| | - Carla Giordano
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
| | - Annalinda Pisano
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Department of Internal Medicine and Medical Specialties, Sapienza University of RomeRome, Italy
| | - Arianna Montanari
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | - Antonio F Campese
- Department of Molecular Medicine, Sapienza University of RomeRome, Italy
| | | | - Daniele Ghezzi
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCSMilan, Italy
| | - Alessia Nasca
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCSMilan, Italy
| | - Helen A Tuppen
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, UK
| | - Maurizia Orlandi
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Department of Molecular Medicine, Sapienza University of RomeRome, Italy
| | - Patrizio Di Micco
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of RomeRome, Italy
| | - Elena Poser
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of RomeRome, Italy
| | - Robert W Taylor
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, UK
| | - Gianni Colotti
- National Research Council of Italy, Institute of Molecular Biology and PathologyRome, Italy
| | - Silvia Francisci
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | - Veronica Morea
- National Research Council of Italy, Institute of Molecular Biology and PathologyRome, Italy
| | - Laura Frontali
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | | | - Giulia d'Amati
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
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25
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Gurudeeban S, Satyavani K, Ramanathan T. Phylogeny of Indian rhizophoraceae based on the molecular data from chloroplast tRNA(LEU)UAA intergenic sequences. Pak J Biol Sci 2013; 16:1130-7. [PMID: 24506012 DOI: 10.3923/pjbs.2013.1130.1137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molecular identification data of unexplored Indian Rhizophoraceae an eco-friendly mangroves are an imperative aspect in molecular phylogenetics. We describe the phylogenetic relationships among the Rhizophoraceae genus Rhizophora, Ceriops and Bruguiera using tRNA Leu (UAA) intron sequences as a molecular marker. The results of present study reveals congeneric relationship between R. apiculata, R. mucronata, B. gymnorhiza indicating a high degree of gene flow within them and the pairwise distribution of study plants among Rhizophoraceae family. The phylogram constructed using tRNA Leu sequence clearly clustered the species of the same genus in individual group. The stem-loop could be divided into two classes, both built up from two base pairing heptanucleotide repeats. Size variation was primarily caused by different numbers of repeats but some strains also contained additional sequences in this stem-loop. The statistical summaries of DNA sequence data can enable to identify the structural signature of the genome as well as to classify phylogenetic relationships among different species reflected in the difference of genetic diversity distributions within their DNA sequences.
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Affiliation(s)
- S Gurudeeban
- Marine Floral Biotechnology Laboratory, Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai 608502, Tamil Nadu, India
| | - K Satyavani
- Marine Floral Biotechnology Laboratory, Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai 608502, Tamil Nadu, India
| | - T Ramanathan
- Marine Floral Biotechnology Laboratory, Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai 608502, Tamil Nadu, India
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Banerjee D, Banerjee A, Mookherjee S, Vishal M, Mukhopadhyay A, Sen A, Basu A, Ray K. Mitochondrial genome analysis of primary open angle glaucoma patients. PLoS One 2013; 8:e70760. [PMID: 23940637 PMCID: PMC3733777 DOI: 10.1371/journal.pone.0070760] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 06/23/2013] [Indexed: 12/24/2022] Open
Abstract
Primary open angle glaucoma (POAG) is a multi-factorial optic disc neuropathy characterized by accelerating damage of the retinal ganglion cells and atrophy of the optic nerve head. The vulnerability of the optic nerve damage leading to POAG has been postulated to result from oxidative stress and mitochondrial dysfunction. In this study, we investigated the possible involvement of the mitochondrial genomic variants in 101 patients and 71 controls by direct sequencing of the entire mitochondrial genome. The number of variable positions in the mtDNA with respect to the revised Cambridge Reference Sequence (rCRS), have been designated "Segregating Sites". The segregating sites present only in the patients or controls have been designated "Unique Segregating Sites (USS)". The population mutation rate (θ = 4Neμ) as estimated by Watterson's θ (θw), considering only the USS, was significantly higher among the patients (p = 9.8 × 10(-15)) compared to controls. The difference in θw and the number of USS were more pronounced when restricted to the coding region (p<1.31 × 10(-21) and p = 0.006607, respectively). Further analysis of the region revealed non-synonymous variations were significantly higher in Complex I among the patients (p = 0.0053). Similar trends were retained when USS was considered only within complex I (frequency 0.49 vs 0.31 with p<0.0001 and mutation rate p-value <1.49×10(-43)) and ND5 within its gene cluster (frequency 0.47 vs 0.23 with p<0.0001 and mutation rate p-value <4.42×10(-47)). ND5 is involved in the proton pumping mechanism. Incidentally, glaucomatous trabecular meshwork cells have been reported to be more sensitive to inhibition of complex I activity. Thus mutations in ND5, expected to inhibit complex I activity, could lead to generation of oxidative stress and favor glaucomatous condition.
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Affiliation(s)
- Deblina Banerjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Antara Banerjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Suddhasil Mookherjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Mansi Vishal
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | | | | | - Analabha Basu
- National Institute of Biomedical Genomics, Kalyani, India
| | - Kunal Ray
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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Jung J, Choi HK. Recognition of two major clades and early diverged groups within the subfamily Cyperoideae (Cyperaceae) including Korean sedges. J Plant Res 2013; 126:335-349. [PMID: 23114970 DOI: 10.1007/s10265-012-0534-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 10/02/2012] [Indexed: 06/01/2023]
Abstract
We aim to present phylogenetic major groups within the subfamily Cyperoideae (Cyperaceae) on the basis of three molecular data sets; nuclear ribosomal internal transcribed spacer and 5.8S ribosomal RNA region, the ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene, and trnL intron and trnL-F intergenic spacer. Three molecular data and two combined data sets were used to obtain robust and detailed phylogenetic trees by using maximum parsimony and Bayesian inference, respectively. We analyzed 81 genera and 426 species of Cyperaceae, including Korean species. We suggest one early diverged group (EDGs), and two major clades (FAEC and SDC) within the subfamily Cyperoideae. And the clade EDGs comprises six tribes (Schoeneae, Bisboeckelereae, Sclerieae, Cryptangieae, Trilepideae, and Rhynchosporeae) at the basal nodes of Cyperoideae. The FAEC clade (posterior probability [PP]/bootstrap value [BS] = 1.00/85) comprises four tribes (Fuireneae, Abildgaardieae, Eleocharideae, Cypereae), and the SDC clade (PP/BS = 1.00/86) comprises three tribes (Scirpeae, Dulichieae, Cariceae). These three clades used for phylogenetic groups in our study will be useful for establishing the major lineage of the sedge family. The phylogeny of Korean sedges was also investigated within the whole phylogeny of Cyperaceae. The 20 genera of Korean sedges were placed in 10 tribes forming 14 clades.
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Affiliation(s)
- Jongduk Jung
- Department of Biological Science, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, South Korea
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28
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Katoh H, Inoue H, Kuchiki F, Ide Y, Uechi N, Iwanami T. Identification of a distinct lineage of Cacopsylla chinensis (Hemiptera: Psyllidae) in Japan on the basis of two mitochondrial DNA sequences. J Econ Entomol 2013; 106:536-542. [PMID: 23786037 DOI: 10.1603/ec12209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Psyllids are a menacing pests of pears (Pyrus spp.) grown in temperate and subtropical regions of the world, including Taiwan and China. Pear psyllids belong to the large genus Cacopsylla (Psyllidae: Psyllinae). Among the 28 psyllid species that infest pear trees, Cacopsylla chinensis (Yang and Li, 1981) is considered the most harmful. Two psyllid outbreaks involving exotic species affected Japanese pear (Pyrus pyrifolia variety culta) orchards in the Saga Prefecture in July and November 2011. The psyllids were morphologically identical to the summer and winter forms of C. chinensis. In this study, we performed DNA sequence analysis of the mitochondrial cytochrome oxidase I-leucine tRNA-cytochrome oxidase II (COI-tRNA(Leu)-COII) and 16S rDNA regions to elucidate the phylogenetic relationships among 82 summer-form psyllids, five winter-form psyllids from several orchards in Japan, and those reported from Taiwan and China. The sequences of the COI-tRNA(LEU)-COII and 16S rDNA regions were identical among all 87 psyllids from Japan, regardless of summer/winter forms or orchards in Saga, Japan. Comparison of nucleotide sequences and phylogenetic analysis differentiated Japanese psyllids from the Taiwanese and Chinese C. chinensis isolates, with approximately 8 and 7% nucleotide difference in the COI-tRNA(LEU)-COII and 16S rDNA regions, respectively. The results suggest that C. chinensis possess a high level of genetic variability and that the psyllids responsible for the outbreak in Saga, Japan belong to a distinct lineage of C. chinensis.
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Affiliation(s)
- H Katoh
- NARO Institute of Fruit Tree Science, Fujimoto 2-1, Tsukuba, Ibaraki 305-8605, Japan
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29
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Jiang C, Zhang YH, Chen M, Yuan Y, Lin SF, Wu ZG. [Authentication of Lonicera japonica using bidirectional PCR amplification of specific alleles]. Zhongguo Zhong Yao Za Zhi 2012; 37:3752-3757. [PMID: 23627173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To identify SNP in flos Lonicerae, and authenticate Lonicera japonica from its adulterants and the mixture by using bidirectional PCR amplification of specific alleles (Bi-PASA). METHOD SNP of L. japonica and its adulterants was identified by using ClustulW to align trnL-trnF sequences of the Lonicera genus from GenBank database. Bi-PASA primer was designed and the PCR reaction systems including annealing temperature optimized. Optimized result was performed in 84 samples to authenticate L. japonica, its adulterants and the mixture. RESULT When the annealing temperature was 61 degrees C, DNA from L. japonica would be amplified 468 bp whereas PCR products from all of the 9 adulterants were 324 bp. The established method also can detect 5% of intentional adulteration DNA into L. japonica. CONCLUSION The Bi-SPASA could authenticate L. japonica from its adulterants and the mixture.
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MESH Headings
- Alleles
- DNA Barcoding, Taxonomic/methods
- DNA, Plant/analysis
- DNA, Plant/genetics
- Flowers/genetics
- Lonicera/classification
- Lonicera/genetics
- Plants, Medicinal/classification
- Plants, Medicinal/genetics
- Polymerase Chain Reaction/methods
- Polymorphism, Single Nucleotide
- RNA, Transfer, Leu/genetics
- RNA, Transfer, Phe/genetics
- Reproducibility of Results
- Species Specificity
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Affiliation(s)
- Chao Jiang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
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30
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Procaccio V, Neckelmann N, Paquis-Flucklinger V, Bannwarth S, Jimenez R, Davila A, Poole JC, Wallace DC. Detection of Low Levels of the Mitochondrial tRNALeu(UUR) 3243A>G Mutation in Blood Derived from Patients with Diabetes. Mol Diagn Ther 2012; 10:381-9. [PMID: 17154655 DOI: 10.1007/bf03256215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Mutations in the human mitochondrial genome have been suspected to play a significant role in the etiological development of mitochondrial diabetes. Detection of the 3243A>G mutation in the mitochondrial transfer RNALeu(UUR) gene (MTTL1), especially at low heteroplasmy levels, is highly desirable since it facilitates the diagnosis and subsequent management of the disease. The proportions of mutant mitochondrial DNA (mtDNA) can vary between tissues and are usually significantly higher in muscle than in blood, but muscle biopsies from patients with diabetes are rarely available. METHODS Here, we describe a technique that can not only determine the presence of MTTL1 3243A>G, but can also estimate the percentage of mutant DNA. The technique is based on the use of the WAVE system for the high-performance liquid chromatography (HPLC)-mediated analysis of mutation-specific restriction fragments derived from mutant PCR amplicons. PCR amplicon restriction fragment analysis by HPLC (PARFAH) can also be used for the detection of other mutations. RESULTS This PARFAH analytical approach led to the discovery of the 3243A>G mutation in blood samples from a series of patients who had initially been reported to lack the mutation, even though matrilineal relatives had been shown to harbor the mutation associated with maternally inherited diabetes and deafness (MIDD) or mitochondrial myopathy encephalopathy lactic acidosis stroke-like episodes (MELAS) phenotypes. We have established that the PARFAH method can reliably detect as little as 1% mutant DNA in a sample, which would normally be missed by commonly used gel electrophoresis or sequencing methods. CONCLUSIONS The PARFAH method not only provides a sensitive, high-throughput, and cost-effective strategy for the detection of low levels of mtDNA mutations in peripheral tissues, but also facilitates the estimation of the percentage of mutant DNA in the sample. The fact that samples can be readily obtained from peripheral tissues in many cases will avoid the need for invasive muscle biopsies. Our ability to detect low levels of mtDNA mutations in blood samples of carriers will allow us to reassess the prevalence of the MTTL1 3243A>G mutation in patients with diabetes.
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Affiliation(s)
- Vincent Procaccio
- Center for Molecular and Mitochondrial Medicine and Genetics, Department of Pediatrics, University of California, Irvine, California 92697, USA.
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31
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García E, Sánchez R, Partida M, de Mingo ML, Calatayud M, Martínez G, Hawkins F. [Patient with diabetes and impaired hearing]. Endocrinol Nutr 2012; 59:220-222. [PMID: 22153565 DOI: 10.1016/j.endonu.2011.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 08/22/2011] [Indexed: 05/31/2023]
MESH Headings
- Adult
- DNA, Mitochondrial/genetics
- Deafness/diagnosis
- Deafness/drug therapy
- Deafness/genetics
- Diabetes Mellitus, Type 2/diagnosis
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/genetics
- Epilepsy/etiology
- Female
- Genes, Mitochondrial
- Hearing Loss, Bilateral/genetics
- Hearing Loss, Conductive/genetics
- Hearing Loss, Mixed Conductive-Sensorineural/genetics
- Humans
- Hypoglycemia/etiology
- Insulin/therapeutic use
- Mitochondrial Diseases
- Mutation, Missense
- Pedigree
- Polymorphism, Restriction Fragment Length
- RNA, Transfer, Leu/genetics
- Ubiquinone/therapeutic use
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32
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Desquiret-Dumas V, Gueguen N, Barth M, Chevrollier A, Hancock S, Wallace DC, Amati-Bonneau P, Henrion D, Bonneau D, Reynier P, Procaccio V. Metabolically induced heteroplasmy shifting and l-arginine treatment reduce the energetic defect in a neuronal-like model of MELAS. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1019-29. [PMID: 22306605 DOI: 10.1016/j.bbadis.2012.01.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 11/17/2022]
Abstract
The m.3243A>G variant in the mitochondrial tRNA(Leu(UUR)) gene is a common mitochondrial DNA (mtDNA) mutation. Phenotypic manifestations depend mainly on the heteroplasmy, i.e. the ratio of mutant to normal mtDNA copies. A high percentage of mutant mtDNA is associated with a severe, life-threatening neurological syndrome known as MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes). MELAS is described as a neurovascular disorder primarily affecting the brain and blood vessels, but the pathophysiology of the disease is poorly understood. We developed a series of cybrid cell lines at two different mutant loads: 70% and 100% in the nuclear background of a neuroblastoma cell line (SH-SY5Y). We investigated the impact of the mutation on the metabolism and mitochondrial respiratory chain activity of the cybrids. The m.3243A>G mitochondrial mutation induced a metabolic switch towards glycolysis in the neuronal cells and produced severe defects in respiratory chain assembly and activity. We used two strategies to compensate for the biochemical defects in the mutant cells: one consisted of lowering the glucose content in the culture medium, and the other involved the addition of l-arginine. The reduction of glucose significantly shifted the 100% mutant cells towards the wild-type, reaching a 90% mutant level and restoring respiratory chain complex assembly. The addition of l-arginine, a nitric oxide (NO) donor, improved complex I activity in the mutant cells in which the defective NO metabolism had led to a relative shortage of NO. Thus, metabolically induced heteroplasmy shifting and l-arginine therapy may constitute promising therapeutic strategies against MELAS.
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Affiliation(s)
- Valerie Desquiret-Dumas
- Department of Biochemistry and Genetics, Angers University Hospital, School of Medicine, Angers, F-49000, France
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33
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Hao ZX, Feng R, Wang ED, Zhu G. 1H, 15N chemical shift assignments of the imino groups in the base pairs of Escherichia coli tRNA(Leu) (CAG). Biomol NMR Assign 2011; 5:71-74. [PMID: 20931304 DOI: 10.1007/s12104-010-9270-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/22/2010] [Indexed: 05/30/2023]
Abstract
tRNA molecules are the adaptors in ribosome-based protein biosynthesis and are stabilized by Mg(2+). However, the detailed mechanism for the Mg(2+) mediated stability is not fully understood. To study the effects of Mg(2+) on conformational flexibility of Escherichia coli tRNA(Leu) (CAG) at millisecond timescale, we applied NMR spectroscopic approach to measure proton exchange rates of imino groups in the presence of different concentration of Mg(2+) and correlated them with the corresponding aminoacylation activity of tRNA(Leu). Here, we report the first part of the above mentioned study, the (1)H, (15)N chemical shift assignments of the imino groups in all base pairs of Escherichia coli tRNA(Leu) (CAG) based on 2D (1)H-(15)N TROSY, 2D NOESY and 3D NOESY-HMQC experiments. This work laid the foundation for the NMR study of tRNA(Leu) (BMRB deposits with accession number 17078).
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Affiliation(s)
- Zhan-Xi Hao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Graduate School of the Chinese Academy of Sciences, Shanghai, China
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Abstract
The case of a middle-aged woman with early-onset diabetes mellitus, hypertrophic cardiomyopathy, premature sensorineural hearing loss and neuropsychiatric symptoms is described. The patient's family history revealed the classical pattern of maternally inherited diabetes and deafness (MIDD) and isolation of mitochondrial DNA from peripheral blood leucocytes showed an A3243G transition in the gene encoding for the tRNA(Leu(UUR)). Thus, the suspected diagnosis of a mitochondrial disorder was confirmed. Cardiac involvement turned out to be the dominating clinical feature in the patient. She died of cardiogenic shock and multiple organ failure within 1 year of diagnosis. Three out of nine affected family members had hypertrophic cardiomyopathy.
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Affiliation(s)
- Bernhard Gerber
- Hematology Clinic, University Hospital Zurich, Zurich, Switzerland.
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35
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Tan SH, Aris EM, Surin J, Omar B, Kurahashi H, Mohamed Z. Sequence variation in the cytochrome oxidase subunit I and II genes of two commonly found blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) in Malaysia. Trop Biomed 2009; 26:173-181. [PMID: 19901904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The mitochondiral DNA region encompassing the cytochrome oxidase subunit I (COI) and cytochrome oxidase subunit II (COII) genes of two Malaysian blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) were studied. This region, which spans 2303bp and includes the COI, tRNA leucine and partial COII was sequenced from adult fly and larval specimens, and compared. Intraspecific variations were observed at 0.26% for Ch. megacephala and 0.17% for Ch. rufifacies, while sequence divergence between the two species was recorded at a minimum of 141 out of 2303 sites (6.12%). Results obtained in this study are comparable to published data, and thus support the use of DNA sequence to facilitate and complement morphology-based species identification.
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Affiliation(s)
- Siew Hwa Tan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
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Oexle K, Oberle J, Finckh B, Kohlschütter A, Nagy M, Seibel P, Seissler J, Hübner C. Islet cell antibodies in diabetes mellitus associated with a mitochondrial tRNA(Leu(UUR)) gene mutation. Exp Clin Endocrinol Diabetes 2009; 104:212-7. [PMID: 8817238 DOI: 10.1055/s-0029-1211445] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An A3243G point mutation of the mitochondrial tRNA(Leu(UUR)) gene was detected in a Caucasian family with maternal diabetes mellitus and signs of mitochondrial dysfunction such as muscular hypotonia, encephalopathy, lactic acidosis, stroke-like episodes (MELAS), neurosensory hearing loss, cardial pre-excitation, and short stature. Low levels (10 JDF) of islet cell antibodies (ICA) in insulin-treated diabetes of the mother and impaired glucose tolerance with high levels of ICA (80 JDF) in her older son indicated that mitochondrial diabetes mellitus may involve beta cell damage. Furthermore, exocrine pancreas cell damage may also occur since the stroke-like episodes of this son were combined with pancreatitis. In all family members HLA types and plasma antioxidants were determined. Normal concentrations of hydro- and lipophilic antioxidants (including ubiquinol-10) were found.
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Affiliation(s)
- K Oexle
- Department of Pediatrics, Humboldt-University Medical Center (Charité), Berlin, Germany
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37
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Akbari M, Skjelbred C, Følling I, Sagen J, Krokan HE. A gel electrophoresis method for detection of mitochondrial DNA mutation (3243 tRNALeu (UUR)) applied to a Norwegian family with diabetes mellitus and hearing loss. Scand J Clin Lab Invest 2009; 64:86-92. [PMID: 15115244 DOI: 10.1080/00365510410004209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Blood cells of selected patients from a large Norwegian family with maternally transmitted diabetes mellitus, hearing loss and muscular dysfunction were screened for possible A3243G mutation tRNA(Leu (UUR)) in mitochondrial DNA. We selected 7 patients from 3 of the 4 generations of the family and 10 unrelated healthy control subjects for mutation analysis using denaturing gradient gel electrophoresis (DGGE) and both manual and automated DNA sequencing. The A3243G mutation was found in peripheral blood cells of all 7 patients, but in none of the controls. The mutation was in the form of heteroplasmy and the amount of mutant DNA was found to be between 10% and 35% of total mtDNA in individual patients. This is the first report of a Norwegian family with maternally inherited diabetes and hearing loss carrying the A3243G mutation in mitochondrial DNA.
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Affiliation(s)
- M Akbari
- Institute of Cancer Research and Molecular Biology, Regional Hospital Trondheim, Norwegian University of Science and Technology, Trondheim, Norway.
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38
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Wang J, Schully KL, Pettis GS. Growth-regulated expression of a bacteriocin, produced by the sweet potato pathogen Streptomyces ipomoeae, that exhibits interstrain inhibition. Appl Environ Microbiol 2009; 75:1236-42. [PMID: 19114519 PMCID: PMC2648181 DOI: 10.1128/aem.01598-08] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 12/19/2008] [Indexed: 11/20/2022] Open
Abstract
Certain strains of the bacterial sweet potato pathogen Streptomyces ipomoeae produce the bacteriocin ipomicin, which inhibits other sensitive strains of the same species. Within the signal-sequence-encoding portion of the ipomicin structural gene ipoA exists a single rare TTA codon, which is recognized in Streptomyces bacteria by the temporally accumulating bldA leucyl tRNA. In this study, ipomicin was shown to stably accumulate in culture supernatants of S. ipomoeae in a growth-regulated manner that did not coincide with the pattern of ipoA expression. Similar growth-regulated production of ipomicin in Streptomyces coelicolor containing the cloned ipoA gene was found to be directly dependent on translation of the ipoA TTA codon by the bldA leucyl tRNA. The results here suggest that bldA-dependent translation of the S. ipomoeae ipoA gene leads to growth-regulated production of the ipomicin precursor, which upon processing to the mature form and secretion stably accumulates in the extracellular environment. To our knowledge, this is the first example of bldA regulation of a bacteriocin in the streptomycetes.
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Affiliation(s)
- Jing Wang
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Abstract
MELAS is the most dominant clinical features among mitochondrial disorders. However the natural course of MELAS has not been clarified yet. In order to elucidate the natural course of MELAS, we have done the Japanese Cohort study on MELAS. By the age of onset, we divided MELAS into two subgroups, a juvenile form (onset is less than 18 years of age) and an adult form (onset is more than 18 years of age). Juvenile form is significantly different from adult form not only in the mean age of onset, but the mean age of death and survival rate (juvenile has 3.2 times higher chance of death than adult). Our date indicate that juvenile form of MELAS is more severe and poor prognosis than those seen in adult form. Based on the hypothesis that MELAS is caused by impaired vasodilation in an intracerebral artery, we evaluated the effects of administering L-arginine, a nitric oxide precursor. Patients were administered L-arginine intravenously at acute phase, or per orally at interictal phase. L-arginine infusions significantly improved all stroke-like symptoms suggesting stroke within 30 min, and oral administration significantly decreased frequency and severity of stroke-like episodes. L-arginine therapy showed promise in treating stroke-like episodes in MELAS.
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Affiliation(s)
- Yasutoshi Koga
- Department of Pediatrics and Child Health, Kurume University School of Medicine
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40
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Takahashi Y, Iida K, Takeno R, Kitazawa R, Kitazawa S, Kitamura H, Fujioka Y, Yamada H, Kanda F, Ohta S, Nishimaki K, Fujimoto M, Kondo T, Iguchi G, Takahashi K, Kaji H, Okimura Y, Chihara K. Hepatic failure and enhanced oxidative stress in mitochondrial diabetes. Endocr J 2008; 55:509-14. [PMID: 18445996 DOI: 10.1507/endocrj.k07e-091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial diabetes is characterized by diabetes and hearing loss in maternal transmission with a heteroplasmic A3243G mutation in the mitochondrial gene. In patients with the mutation, it has been reported that hepatic involvement is rarely observed. We demonstrated a case of hypertrophic cardiomyopathy and hepatic failure with mitochondrial diabetes. To clarify the pathogenesis we analyzed the mitochondrial ultrastructure in the myocytes, the reactive oxygen species (ROS) production in the liver and the status of heteroplasmy of the mitochondrial A3243G mutation in the organs involved. In cardiomyocytes and skeletal muscle, electron microscopic analysis demonstrated typical morphological mitochondrial abnormalities. Immunohistochemical analysis demonstrated enhanced ROS production associated with marked steatosis in the liver, which is often associated with mitochondrial dysfunction. Analysis of the A3243G mutation revealed a substantial ratio of heteroplasmy in these organs including the liver. The presence of steatosis and enhanced oxidative stress in the liver suggested that hepatic failure was associated with mitochondrial dysfunction.
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Affiliation(s)
- Yutaka Takahashi
- Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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Abstract
Two species of thalloid liverworts, Blasia pusilla and Cavicularia densa, form stable symbioses with nitrogen-fixing cyanobacteria. Both bryophytes promote the persistence of their cyanobacterial associations by producing specialized gemmae, which facilitate the simultaneous dispersal of the host and its nitrogen-fixing symbionts. Here the genetic diversity of cyanobacterial symbionts of Blasia and Cavicularia is examined. The results indicate that the primary symbionts of both bryophytes are closely related and belong to a specific group of symbiotic Nostoc strains. Related strains have previously been reported from hornworts and cycads, and from many terricolous cyanolichens. The evolutionary origins of all these symbioses may trace back to pre-Permian times. While the laboratory strain Nostoc punctiforme PCC 73102 has been widely used in experimental studies of bryophyte-Nostoc associations, sequence-identical cyanobionts have not yet been identified from thalloid liverworts in the field.
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Affiliation(s)
- Jouko Rikkinen
- Department of Biological and Environmental Sciences, PO Box 65, University of Helsinki, FIN-00014 Helsinki, Finland.
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Miyata Y, Sugita C, Maruyama K, Sugita M. RNA editing in the anticodon of tRNA Leu (CAA) occurs before group I intron splicing in plastids of a moss Takakia lepidozioides S. Hatt. & Inoue. Plant Biol (Stuttg) 2008; 10:250-255. [PMID: 18304199 DOI: 10.1111/j.1438-8677.2007.00027.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
RNA editing of cytidine (C) to uridine (U) transitions occurs in plastids and mitochondria of most land plants. In this study, we amplified and sequenced the group I intron-containing tRNA Leu gene, trnL-CAA, from Takakia lepidozioides, a moss. DNA sequence analysis revealed that the T. lepidozioides tRNA Leu gene consisted of a 35-bp 5' exon, a 469-bp group I intron and a 50-bp 3' exon. The intron was inserted between the first and second position of the tRNA Leu anticodon. In general, plastid tRNA Leu genes with a group I intron code for a TAA anticodon in most land plants. This strongly suggests that the first nucleotide of the CAA anticodon could be edited in T. lepidozioides plastids. To investigate this possibility, we analysed cDNAs derived from the trnL-CAA transcripts. We demonstrated that the first nucleotide C of the anticodon was edited to create a canonical UAA anticodon in T. lepidozioides plastids. cDNA sequencing analyses of the spliced or unspliced tRNA Leu transcripts revealed that, while the spliced tRNA was completely edited, editing in the unspliced tRNAs were only partial. This is the first experimental evidence that the anticodon editing of tRNA occurs before RNA splicing in plastids. This suggests that this editing is a prerequisite to splicing of pre-tRNA Leu.
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Affiliation(s)
- Y Miyata
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
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Montanari A, Besagni C, De Luca C, Morea V, Oliva R, Tramontano A, Bolotin-Fukuhara M, Frontali L, Francisci S. Yeast as a model of human mitochondrial tRNA base substitutions: investigation of the molecular basis of respiratory defects. RNA 2008; 14:275-283. [PMID: 18065717 PMCID: PMC2212258 DOI: 10.1261/rna.740108] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 10/16/2007] [Indexed: 05/25/2023]
Abstract
We investigate the relationships between acylation defects and structure alterations due to base substitutions in yeast mitochondrial (mt) tRNA(UUR)(Leu). The studied substitutions are equivalent to the A3243G and T3250C human pathogenetic tRNA mutations. Our data show that both mutations can produce tRNA(UUR)(Leu) acylation defects, although to a different extent. For mutant A14G (equivalent to MELAS A3243G base substitution), the presence of the tRNA and its defective aminoacylation could be observed only in the nuclear context of W303, a strain where the protein synthesis defects caused by tRNA base substitutions are far less severe than in previously studied strains. For mutant T20C (equivalent to the MM/CPEO human T3250C mutation), the acylation defect was less severe, and a thermosensitive acylation could be detected also in the MCC123 strain. The correlation between the severity of the in vivo phenotypes of yeast tRNA mutants and those obtained in in vitro studies of human tRNA mutants supports the view that yeast is a suitable model to study the cellular and molecular effects of tRNA mutations involved in human pathologies. Furthermore, the yeast model offers the possibility of modulating the severity of yeast respiratory phenotypes by studying the tRNA mutants in different nuclear contexts. The nucleotides at positions 14 and 20 are both highly conserved in yeast and human mt tRNAs; however, the different effect of their mutations can be explained by structure analyses and quantum mechanics calculations that can shed light on the molecular mechanisms responsible for the experimentally determined defects of the mutants.
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MESH Headings
- Acetylation
- Base Sequence
- Cell Respiration/genetics
- Humans
- Models, Biological
- Mutation
- Nucleic Acid Conformation
- Phenotype
- RNA/chemistry
- RNA/genetics
- RNA/metabolism
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Mitochondrial
- RNA, Transfer, Leu/chemistry
- RNA, Transfer, Leu/genetics
- RNA, Transfer, Leu/metabolism
- Saccharomyces cerevisiae/genetics
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Affiliation(s)
- Arianna Montanari
- Department of Cell and Developmental Biology, Pasteur Institute-Fondazione Cenci Bolognetti, University Sapienza, 00185 Rome, Italy
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Nishioka J, Akita Y, Yatsuga S, Katayama K, Matsuishi T, Ishibashi M, Koga Y. Inappropriate intracranial hemodynamics in the natural course of MELAS. Brain Dev 2008; 30:100-5. [PMID: 17664050 DOI: 10.1016/j.braindev.2007.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 06/22/2007] [Accepted: 06/24/2007] [Indexed: 11/17/2022]
Abstract
The abnormalities of intracranial hemodynamics associated with strokelike episodes in MELAS are variable depend on the time phase from the onset of strokelike episodes and on the progression of the dementia state. To clarify the regional cerebral blood flows (rCBF) in the natural course of MELAS is very important to understand the pathogenic mechanism of this disorder, either cytopathy, angiopathy or both. We analyzed the serial studies of brain statistical parametric mapping (SPM) 99 single photon emission computed tomography (SPECT) in 5 MELAS patients in maximum 10 years interval, who fulfilled the clinical, pathological and genetic criteria of MELAS, and have an A3243G mutation in the mitochondrial tRNA(Leu(UUR)) gene. SPM is a proven and effective method for the voxel-by-voxel analysis of functional images which show the advantage in its promise of fully automated neurophysiological imaging analysis throughout the whole brain using various statistical analyses. SPECT acquisition was initiated and was reconstructed by iterative algorithm and were processed and analyzed with SPM 99 for Windows software. Statistics were displayed as Z scores (threshold: P < 0.01). The inappropriate intracranial hemodynamics was found not only at the acute but at the interictal phase, and was getting worse as the disease progress. Hypoperfusion in the posterior cingulate cortex was always observed (corrected P < 0.01) in MELAS patients, which is the typical finding reported in Alzheimer's disease. The inappropriate intracranial hemodynamics is a common feature and may be related with mitochondrial angiopathy in the natural course of MELAS.
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Affiliation(s)
- Junko Nishioka
- Department of Pediatrics and Child Health, Kurume University School of Medicine, Kurume City, Fukuoka, Japan
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45
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Hyvärinen AK, Pohjoismäki JLO, Reyes A, Wanrooij S, Yasukawa T, Karhunen PJ, Spelbrink JN, Holt IJ, Jacobs HT. The mitochondrial transcription termination factor mTERF modulates replication pausing in human mitochondrial DNA. Nucleic Acids Res 2007; 35:6458-74. [PMID: 17884915 PMCID: PMC2095818 DOI: 10.1093/nar/gkm676] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The mammalian mitochondrial transcription termination factor mTERF binds with high affinity to a site within the tRNA(Leu(UUR)) gene and regulates the amount of read through transcription from the ribosomal DNA into the remaining genes of the major coding strand of mitochondrial DNA (mtDNA). Electrophoretic mobility shift assays (EMSA) and SELEX, using mitochondrial protein extracts from cells induced to overexpress mTERF, revealed novel, weaker mTERF-binding sites, clustered in several regions of mtDNA, notably in the major non-coding region (NCR). Such binding in vivo was supported by mtDNA immunoprecipitation. Two-dimensional neutral agarose gel electrophoresis (2DNAGE) and 5' end mapping by ligation-mediated PCR (LM-PCR) identified the region of the canonical mTERF-binding site as a replication pause site. The strength of pausing was modulated by the expression level of mTERF. mTERF overexpression also affected replication pausing in other regions of the genome in which mTERF binding was found. These results indicate a role for TERF in mtDNA replication, in addition to its role in transcription. We suggest that mTERF could provide a system for coordinating the passage of replication and transcription complexes, analogous with replication pause-region binding proteins in other systems, whose main role is to safeguard the integrity of the genome whilst facilitating its efficient expression.
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Affiliation(s)
- Anne K. Hyvärinen
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Jaakko L. O. Pohjoismäki
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Aurelio Reyes
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Sjoerd Wanrooij
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Takehiro Yasukawa
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Pekka J. Karhunen
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Johannes N. Spelbrink
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Ian J. Holt
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
| | - Howard T. Jacobs
- Institute of Medical Technology and Tampere University Hospital, FI-33014, University of Tampere, Finland, MRC-Dunn Human Nutrition Unit, Cambridge, UK, Department of Forensic Medicine and Tampere University Hospital, FI-33014, University of Tampere, Finland and Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, UK
- *To whom correspondence should be addressed. +358 3 3551 7731+358 3 3551 7710; E-mail:
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46
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Hesketh A, Bucca G, Laing E, Flett F, Hotchkiss G, Smith CP, Chater KF. New pleiotropic effects of eliminating a rare tRNA from Streptomyces coelicolor, revealed by combined proteomic and transcriptomic analysis of liquid cultures. BMC Genomics 2007; 8:261. [PMID: 17678549 PMCID: PMC2000904 DOI: 10.1186/1471-2164-8-261] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 08/02/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Streptomyces coelicolor, bldA encodes the only tRNA for a rare leucine codon, UUA. This tRNA is unnecessary for growth, but is required for some aspects of secondary metabolism and morphological development. We describe a transcriptomic and proteomic analysis of the effects of deleting bldA on cellular processes during submerged culture: conditions relevant to the industrial production of antibiotics. RESULTS At the end of rapid growth, a co-ordinated transient up-regulation of about 100 genes, including many for ribosomal proteins, was seen in the parent strain but not the DeltabldA mutant. Increased basal levels of the signal molecule ppGpp in the mutant strain may be responsible for this difference. Transcripts or proteins from a further 147 genes classified as bldA-influenced were mostly expressed late in culture in the wild-type, though others were significantly transcribed during exponential growth. Some were involved in the biosynthesis of seven secondary metabolites; and some have probable roles in reorganising metabolism after rapid growth. Many of the 147 genes were "function unknown", and may represent unknown aspects of Streptomyces biology. Only two of the 147 genes contain a TTA codon, but some effects of bldA could be traced to TTA codons in regulatory genes or polycistronic operons. Several proteins were affected post-translationally by the bldA deletion. There was a statistically significant but weak positive global correlation between transcript and corresponding protein levels. Different technical limitations of the two approaches were a major cause of discrepancies in the results obtained with them. CONCLUSION Although deletion of bldA has very conspicuous effects on the gross phenotype, the bldA molecular phenotype revealed by the "dualomic" approach has shown that only about 2% of the genome is affected; but this includes many previously unknown effects at a variety of different levels, including post-translational changes in proteins and global cellular physiology.
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Affiliation(s)
- Andy Hesketh
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK
| | - Giselda Bucca
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Emma Laing
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Fiona Flett
- Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester, M1 7ND, UK
| | - Graham Hotchkiss
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Colin P Smith
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Keith F Chater
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK
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47
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Janssen GMC, Hensbergen PJ, van Bussel FJ, Balog CIA, Maassen JA, Deelder AM, Raap AK. The A3243G tRNALeu(UUR) mutation induces mitochondrial dysfunction and variable disease expression without dominant negative acting translational defects in complex IV subunits at UUR codons. Hum Mol Genet 2007; 16:2472-81. [PMID: 17656376 DOI: 10.1093/hmg/ddm203] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in the mitochondrial tRNA(Leu(UUR)) gene are associated with a large variety of human diseases through a largely undisclosed mechanism. The A3243G tRNA(Leu(UUR)) mutation leads to reduction of mitochondrial DNA (mtDNA)-encoded proteins and oxidative phosphorylation activity even when the cells are competent in mitochondrial translation. These two aspects led to the suggestion that a dominant negative factor may underlie the diversity of disease expression. Here we test the hypothesis that A3243G tRNA(Leu(UUR)) generates such a dominant negative gain-of-function defect through misincorporation of amino acids at UUR codons of mtDNA-encoded proteins. Using an anti-complex IV immunocapture technique and mass spectrometry, we show that the mtDNA-encoded cytochrome c oxidase I (COX I) and COX II exist exclusively with the correct amino acid sequences in A3243G cells in a misassembled complex IV. A dominant negative component therefore cannot account for disease phenotype, leaving tissue-specific accumulation by mtDNA segregation as the most likely cause of variable mitochondrial disease expression.
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Affiliation(s)
- George M C Janssen
- Department of Molecular Cell Biology, Leiden University Medical Centre, Post Zone S1-P, Einthovenweg 20, PO Box 9600, 2300RC Leiden, The Netherlands.
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Ahari SE, Houshmand M, Panahi MSS, Kasraie S, Moin M, Bahar MA. Investigation on Mitochondrial tRNALeu/Lys, NDI and ATPase 6/8 in Iranian Multiple Sclerosis Patients. Cell Mol Neurobiol 2007; 27:695-700. [PMID: 17619138 DOI: 10.1007/s10571-007-9160-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2006] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
As with chromosomal DNA, the mitochondrial DNA (mtDNA) can contain mutations that are highly pathogenic . In fact, many diseases of the central nervous system are known to be caused by mutations in mtDNA. Dysfunction of the mitochondrial Respiratory Chain (RC) has been shown in patients with neurological disease including Alzheimer's disease (AD), Parkinson's disease (PD) and Multiple sclerosis (MS). MS is a demyelinating disease of central nervous system characterized by morphological hallmarks of inflammation, demyelination and axonal loss. Considering this importance, we decided to investigate several highly mutative parts of mtDNA for point mutations as MT-LTI (tRNA(Leucine1(UUA/G))), MT-NDI (NADH Dehydrogenase subunit 1), MT-COII (Cytochrome c oxidase subunit II), MT-TK (tRNA(Lysine)), MT-ATP8 (ATP synthase subunit F0 8) and MT-ATP6 (ATP synthase subunit F0 6) in 20 Iranian MS patients and 80 age-matched control subjects by PCR and automated DNA sequencing to evaluate any probable point mutations. Our results revealed that 15 (75%) out of 20 MS patients had point mutations. Some of point mutations were newly found in this study. This study suggested that point mutation occurred in mtDNA might be involved in pathogenesis of MS.
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Maeso E, Rueda A, Jiménez S, Del Hoyo P, Martín R, Cabello A, Mendoza LM, Arenas J, Campos Y. A novel mutation in the mitochondrial DNA tRNA Leu (UUR) gene associated with late-onset ocular myopathy. Neuromuscul Disord 2007; 17:415-8. [PMID: 17363246 DOI: 10.1016/j.nmd.2007.01.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/29/2006] [Accepted: 01/30/2007] [Indexed: 11/26/2022]
Abstract
We identified a novel G3283A transition in the mitochondrial DNA tRNA(Leu (UUR)) gene in a patient with ptosis, ophthalmoparesis and hyporeflexia. Muscle biopsy showed cytochrome oxidase positive ragged-red fibers, and defects of complexes I, III and IV of the mitochondrial respiratory chain. The mutation was heteroplasmic in muscle of the proband, being absent in her blood. Ragged-red fibers harbored greater levels of mutant genomes than normal fibers. The G3283A mutation affects a strictly conserved base pair in the TPsiC stem of the gene and was not found in controls, thus satisfying the accepted criteria for pathogenicity.
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Affiliation(s)
- E Maeso
- Centro de Investigación, Hospital 12 de Octubre, Avda. de Córdoba km 5.4, 28041 Madrid, Spain
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Mkaouar-Rebai E, Tlili A, Masmoudi S, Belguith N, Charfeddine I, Mnif M, Triki C, Fakhfakh F. Mutational analysis of the mitochondrial tRNALeu(UUR) gene in Tunisian patients with mitochondrial diseases. Biochem Biophys Res Commun 2007; 355:1031-7. [PMID: 17336924 DOI: 10.1016/j.bbrc.2007.02.083] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/14/2007] [Indexed: 11/29/2022]
Abstract
The mitochondrial tRNA(Leu(UUR)) gene (MTTL) is a hot spot for pathogenic mutations that are associated with mitochondrial diseases with various clinical features. Among these mutations, the A3243G mutation was associated with various types of mitochondrial multisystem disorders, such as MIDD, MELAS, MERRF, PEO, hypertrophic cardiomyopathy, and a subtype of Leigh syndrome. We screened 128 Tunisian patients for the A3243G mutation in the mitochondrial tRNA(Leu(UUR)) gene. This screening was carried out using PCR-RFLP with the restriction endonuclease ApaI. None of the 128 patients or the 100 controls tested were found to carry the mitochondrial A3243G mutation in the tRNA(Leu(UUR)) gene in homoplasmic or heteroplasmic form. After direct sequencing of the entire mitochondrial tRNA(Leu(UUR)) gene and a part of the mitochondrial NADH dehydrogenase 1, we found neither mutations nor polymorphisms in the MTTL1 gene in the tested patients and controls, and we confirmed the absence of the A3243G mutation in this gene. We also found a T3396C transition in the ND1 gene in one family with NSHL which was absent in the other patients and in 100 controls. Neither polymorphisms nor other mutations were found in the mitochondrial tRNA(Leu(UUR)) gene in the tested patients.
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Affiliation(s)
- Emna Mkaouar-Rebai
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine, 3029 Sfax, Tunisia.
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