Eukaryotic-type elongator tRNAMet of Trypanosoma brucei becomes formylated after import into mitochondria

@article{Tan2002EukaryotictypeET,
  title={Eukaryotic-type elongator tRNAMet of Trypanosoma brucei becomes formylated after import into mitochondria},
  author={Timothy H. P. Tan and Natacha Bochud-Allemann and E. Horn and A. Schneider},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={2002},
  volume={99},
  pages={1152 - 1157}
}
The mitochondrion of Trypanosoma brucei lacks tRNA genes. Its translation system therefore depends on the import of cytosolic, nucleus-encoded tRNAs. Thus, most trypanosomal tRNAs function in both the cytosol and the mitochondrion, and all are of the eukaryotic type. This is also the case for the elongator tRNAMet, whereas the only other trypanosomal tRNAMet, the eukaryotic initiator, is found exclusively in the cytosol. Unlike their cytosolic counterparts, organellar initiator tRNAsMet carry a… Expand
Mitochondrial Initiation Factor 2 of Trypanosoma brucei Binds Imported Formylated Elongator-type tRNAMet*
TLDR
The present study has identified initiation factor 2 of T. brucei and shown that its carboxyl-terminal domain specifically binds formylated trypanosomal elongator tRNAMet, suggesting that the main determinant recognized is theformylated methionine. Expand
The T-stem determines the cytosolic or mitochondrial localization of trypanosomal tRNAsMet.
TLDR
It was shown that the tRNA(Met) T-stem localization determinants are also functional in the context of two other tRNAs, and in vivo analysis of the modified nucleotides found in the initiator tRNA (Met) indicates that the T- stem localization determinant do not require modifieducleotides. Expand
Elongation factor 1a mediates the specificity of mitochondrial tRNA import in T. brucei
TLDR
It is shown that ablation of cytosolic eEF1a, but not of initiation factor 2, inhibits mitochondrial import of newly synthesized tRNAs well before translation or growth is affected. Expand
Location alters tRNA identity: Trypanosoma brucei's cytosolic elongator tRNAMet is both the initiator and elongator in mitochondria
  • N. Martin
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 2002
TLDR
The work of Tan et al. (4) in this issue of PNAS provides a second exception with several different twists as they show that the function of a tRNA in initiation and/or elongation depends on its location. Expand
Mitochondrial translation in absence of local tRNA aminoacylation and methionyl tRNAMet formylation in Apicomplexa
TLDR
This study reveals that aaRSs are either cytosolic, apicoplastic or shared between the two compartments by dual targeting but are absent from the mitochondrion of Apicomplexa, suggesting that tRNAs are very likely imported in their aminoacylated form. Expand
Mitochondrial translation is essential in bloodstream forms of Trypanosoma brucei
TLDR
The results show that mitochondrial tRNA import is a constitutive process that must be mediated by proteins that are expressed in both forms of the life cycle and that are not encoded in the mitochondrial genome. Expand
Mitochondrial tRNA Import in Toxoplasma gondii*
TLDR
Results provide the first experimental evidence for mitochondrial tRNA import in apicomplexans and indicate that the only other taxon that imports the whole set of mitochondrial tRNAs are the trypanosomatids. Expand
Dual targeting of a single tRNA(Trp) requires two different tryptophanyl-tRNA synthetases in Trypanosoma brucei.
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RNA interference analysis established that both Trp RS1 and TrpRS2 are essential for growth and required for cytosolic and mitochondrial tryptophanyl-tRNA formation, respectively, and the notion that, in an organism, all nuclear-encoded tRNAs assigned to a given amino acid are charged by a single aminoacyl-t RNA synthetase is not universally valid. Expand
Dual targeting of isoleucyl-tRNA synthetase in Trypanosoma brucei is mediated through alternative trans-splicing
TLDR
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Steady-state levels of imported tRNAs in Chlamydomonas mitochondria are correlated with both cytosolic and mitochondrial codon usages
TLDR
It is provided unprecedented evidence that the steady-state level of a mitochondrial tRNA is linked not only to the frequency of the cognate codon in mitochondria but also to its frequency in the cytosol, then allowing optimal mitochondrial translation. Expand
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TLDR
Import of heterologous tRNAs in their own genomic contexts supports the conclusion that no specific targeting signals are necessary to import t RNAs into mitochondria of T. brucei, but rather that the tRNA structure itself is sufficient to specify import. Expand
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The mutant tRNA(Tyr) has been expressed in transformed cells and its import into mitochondria has been demonstrated, suggesting that the modified cytidine residue is not required for import and therefore may be involved in adapting imported tRNAs to specific requirements of the mitochondrial translation machinery. Expand
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TLDR
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How does the cellular protein synthetic machinery distinguish initiator tRNA from all of the other tRNAs? What is the mechanism by which the initiator tRNA is sequestered for use exclusively inExpand
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