Identification and characterization of mouse MTO1 gene related to mitochondrial tRNA modification

Li, Ronghua; Li, Xiaoming; Yan, Qinfeng; Mo, Jun Qin; Guan, Min‐Xin

doi:10.1016/s0167-4781(03)00160-x

Cited by 20 publications

(17 citation statements)

References 31 publications

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“…The gidA gene also appears to be involved, as suggested by indirect genetic evidence (15,16). Although MSS1 and MTO1 were found to be the respective homologs of the mnmE and gidA genes in both human and yeast (17,18), it has 4) were analyzed by APM gel electrophoresis and Northern blotting. The gels of lanes 1 and 2 contain APM, whereas the gels of lanes 3 and 4 lack APM.…”

Section: Identification Of Mitochondrial Trna-specific 2-thiouridylasmentioning

confidence: 99%

“…This indicates that the C5 and 2-thio modifications of the wobble uridine act synergistically in promoting cognate codon decoding efficiency. Because the human homologs of MSS1 and MTO1 have been shown to be localized in the mitochondria (17,18), it appears that these proteins are responsible for the initial steps taken to synthesize the m 5 U or m 5 s 2 U modifications of mt tRNAs. It is also likely that there are some unidentified genes other than MSS1 and MTO1 that participate in these modifications, including a putative taurine-transferase for the biosynthesis of m 5 U (5).…”

Section: Trna-modifying Enzymes and Mitochondrial Diseasesmentioning

confidence: 99%

“…In the case of the C5 modification of the wobble uridines, mnmE (trmE) and gidA are known to be required for the initial step in the modification of E. coli tRNAs, namely, mnm 5 U (5-methylaminomethyuridine) synthesis (14 -16). MSS1 and MTO1 were found to be the respective homologs of the mnmE and gidA genes in both human and yeast (17,18). The protein products of these genes were shown to localize in the mitochondria as a heterodimer complex, and their mutants are associated with respiratory defects (19).…”

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confidence: 99%

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Mitochondria-specific RNA-modifying Enzymes Responsible for the Biosynthesis of the Wobble Base in Mitochondrial tRNAs

Umeda

Suzuki

Yukawa

et al. 2005

Journal of Biological Chemistry

199

237

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Human mitochondrial (mt) tRNALys has a taurine-containing modified uridine, 5-taurinomethyl-2-thiouridine (m 5 s 2 U), at its anticodon wobble position. We previously found that the mt tRNA Lys , carrying the A8344G mutation from cells of patients with myoclonus epilepsy associated with ragged-red fibers (MERRF), lacks the m 5 s 2 U modification. Here we describe the identification and characterization of a tRNA-modifying enzyme MTU1 (mitochondrial tRNA-specific 2-thiouridylase 1) that is responsible for the 2-thiolation of the wobble position in human and yeast mt tRNAs. Disruption of the yeast MTU1 gene eliminated the 2-thio modification of mt tRNAs and impaired mitochondrial protein synthesis, which led to reduced respiratory activity. Furthermore, when MTO1 or MSS1, which are responsible for the C5 substituent of the modified uridine, was disrupted along with MTU1, a much more severe reduction in mitochondrial activity was observed. Thus, the C5 and 2-thio modifications act synergistically in promoting efficient cognate codon decoding. Partial inactivation of MTU1 in HeLa cells by small interference RNA also reduced their oxygen consumption and resulted in mitochondria with defective membrane potentials, which are similar phenotypic features observed in MERRF.The precise codon-anticodon pairing that occurs during translation requires a post-transcriptional modification at the anticodon first position (the wobble position) of the tRNA (1-4). In mammalian mitochondrial (mt) 1 tRNAs, we recently discovered novel taurine-bearing modified uridines at the wobble position, namely, 5-taurinomethyluridine (m 5 U) in mt tRNA Leu(UUR) and 5-taurinomethyl-2-thiouridine (m 5 s 2 U) in mt tRNA Lys (5). We then showed that these wobble modifications are generated by the direct incorporation of taurine supplied by the medium. This is the first time it has been shown that taurine is a component of biological macromolecules.We have also shown that the taurine-bearing modifications do not occur in mutant mt tRNAs that contain pathogenic point mutations that are associated with mitochondrial encephalomyopathies (6, 7). Point mutations in mt tRNA genes are known to be responsible for a wide spectrum of human diseases that are caused by mitochondrial dysfunction. We found that the mt tRNA Leu(UUR) molecules obtained from pathogenic cells of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) patients (8), who have either the A3243G or the T3271C mutation, lack the m 5 U modification (6). To examine decoding disorder of the mutant tRNA due to the wobble modification deficiency independent of the pathogenic point mutation itself, we used a molecular surgery to construct a mt tRNA Leu(UUR) lacking the taurine modification but without the pathogenic mutation. This "operated" mt tRNA Leu(UUR) without the taurine modification showed severely reduced UUG translation but no decrease in UUA translation. We thus concluded that the UUG codon-specific translational defect of the mutant mt tRNA Leu(UUR...

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Section: Identification Of Mitochondrial Trna-specific 2-thiouridylasmentioning

confidence: 99%

Section: Trna-modifying Enzymes and Mitochondrial Diseasesmentioning

confidence: 99%

mentioning

confidence: 99%

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Mitochondria-specific RNA-modifying Enzymes Responsible for the Biosynthesis of the Wobble Base in Mitochondrial tRNAs

Umeda

Suzuki

Yukawa

et al. 2005

Journal of Biological Chemistry

199

237

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“…4,5,6 The synthesis of mnm 5 s 2 U34 is a multiple step process catalyzed by an enzyme complex 7,8. Of these, MnmE (homolog of Mss1/Gtpbp3),8,9 GidA (homolog of Mto1)7,10 and MnmA/TrmU (homolog of Mto2)11,12 are components of the enzyme complex responsible for the biosynthesis of mnm 5 s 2 U34. In fact, MnmE and GidA assemble in a functional complex involved in the formation of carboxymethylaminomethyl (cmnm) group at position 5 of U 34 of several tRNAs including tRNA Lys , tRNA Glu and tRNA Gln ,7,8,13,14,15 while MnmA, together with other proteins, catalyzes the thiolation at position 2 of U 34 of tRNA Lys , tRNA Glu and tRNA Gln.…”

Section: Introductionmentioning

confidence: 99%

Combination of the Loss of cmnm5U34 with the Lack of s2U34 Modifications of tRNALys, tRNAGlu, and tRNAGln Altered Mitochondrial Biogenesis and Respiration

Wang¹,

Yan²,

Guan³

2010

Journal of Molecular Biology

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Yeast Saccharomyces cerevisiae MTO2, MTO1 and MSS1 genes encoded highly conserved tRNA modifying enzymes for the biosynthesis of cmnm 5 s 2 U 34 in mitochondrial tRNA Lys , tRNA Glu and tRNA Gln . In fact, Mto1p and Mss1p are involved in the biosynthesis of the cmnm 5 group (cmnm 5 U34), while Mto2p is responsible for the 2-thiouridylation (s 2 U 34 ) of these tRNAs. Previous studies showed that partial modifications at U 34 in mitochondrial tRNA enabled mto1, mto2 and mss1 strains to respire. In this report, we investigated the functional interaction between MTO2, MTO1 and MSS1 genes by using the mto2, mto1 and mss1 single, double and triple mutants. Strikingly, the deletion of MTO2 was synthetically lethal with a mutation of MSS1 or deletion of MTO1 on medium containing glycerol, but not on medium containing glucose. Interestingly, there were no detectable levels of 9 tRNAs including tRNA Lys , tRNA Glu and tRNA Gln in mto2/mss1, mto2/ mto1 and mto2/mto1/mss1 strains. Furthermore, mto2/mss1, mto2/mto1 and mto2/mto1/mss1 mutants exhibited extremely low levels of COX1 and CYTB mRNA, 15S and 21S rRNA as well as the complete loss of mitochondrial protein synthesis. The synthetic enhancement combinations likely resulted from the completely abolished modification at U 34 of tRNA Lys , tRNA Glu and tRNA Gln , caused by the combination of eliminating the 2-thiouridylation by the mto2 mutation with the absence of the cmnm 5 U34 by the mto1 or mss1 mutation. The complete loss of modifications at U 34 of tRNAs altered mitochondrial RNA metabolisms, causing a degradation of mitochondrial tRNA, mRNA and rRNAs. As a result, failures in mitochondrial RNA metabolisms were responsible for the complete loss of mitochondrial translation. Consequently, defects in mitochondrial protein synthesis caused the instability of their mitochondrial genomes, thus producing the respiratory deficient phenotypes. Therefore, our findings demonstrated a critical role of modifications at U 34 of tRNA Lys , tRNA Glu and tRNA Gln in maintenance of mitochondrial genome, mitochondrial RNA stability, translation and respiratory function.

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“…Mto1p/GidA is involved in the biosynthesis for the C5 modification of mnm 5 s 2 U34 of tRNA Lys , tRNA Glu and tRNA Gln in E. coli and yeast mitochondria (Yim et al, 2006; Umeda et al, 2005; Li et al, 2002, 2003). E. coli gidA mutants exhibited alterations in biosynthesis of mnm 5 s 2 U34 and translational frameshift (Brégeon et al, 2001; Yim et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Mutation in MTO1 involved in tRNA modification impairs mitochondrial RNA metabolism in the yeast Saccharomyces cerevisiae

2009

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The yeast MTO1 gene encodes an evolutionarily conserved protein for the biosynthesis of the 5-carboxymethylaminomethyl group of cmnm 5 s 2 U in the wobble position of mitochondrial tRNA. However, mto1 null mutant expressed the respiratory deficient phenotype only when coupled with the C1409G mutation of mitochondrial 15S rRNA. To further understand the role of MTO1 in mitochondrial RNA metabolism, the yeast mto1 null mutants carrying either wild-type (P S ) or 15S rRNA C1409G allele (P R ) have been characterized by examining the steady-state levels, aminoacylation capacity of mitochondrial tRNA, mitochondrial gene expression and petite formation. The steady-state levels of tRNA Lys , tRNA Glu , tRNA Gln , tRNA Leu , tRNA Gly , tRNA Arg and tRNA Phe were decreased significantly while those of tRNA Met and tRNA His were not affected in the mto1 strains carrying the P S allele. Strikingly, the combination of the mto1 and C1409G mutations gave rise to the synthetic phenotype for some of the tRNAs, especially in tRNA Lys , tRNA Met and tRNA Phe . Furthermore, the mto1 strains exhibited a marked reduction in the aminoacylation levels of mitochondrial tRNA Lys , tRNA Leu , tRNA Arg but almost no effect in those of tRNA His . In addition, the steady-state levels of mitochondrial COX1, COX2, COX3, ATP6 and ATP9 mRNA were markedly decreased in mto1 strains. These data strongly indicate that unmodified tRNA caused by the deletion of MTO1 gene caused the instability of mitochondrial tRNAs and mRNAs and an impairment of aminoacylation of mitochondrial tRNAs. Consequently, the deletion of MTO1 gene acts in synergy with the 15S rRNA C1409G mutation, leading to the loss of COX1 synthesis and subsequent respiratory deficient phenotype.

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Identification and characterization of mouse MTO1 gene related to mitochondrial tRNA modification

Cited by 20 publications

References 31 publications

Mitochondria-specific RNA-modifying Enzymes Responsible for the Biosynthesis of the Wobble Base in Mitochondrial tRNAs

Mitochondria-specific RNA-modifying Enzymes Responsible for the Biosynthesis of the Wobble Base in Mitochondrial tRNAs

Combination of the Loss of cmnm5U34 with the Lack of s2U34 Modifications of tRNALys, tRNAGlu, and tRNAGln Altered Mitochondrial Biogenesis and Respiration

Mutation in MTO1 involved in tRNA modification impairs mitochondrial RNA metabolism in the yeast Saccharomyces cerevisiae

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