Wobble modification defect in tRNA disturbs codon-anticodon interaction in a mitochondrial disease

Takehiro Yasukawa, Tsutomu Suzuki, Norie Ishii, Shigeo Ohta, Kimitsuna Watanabe

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207 Citations (Scopus)


We previously showed that in mitochondrial tRNALys with an A8344G mutation responsible for myoclonus epilepsy associated with ragged-red fibers (MERRF), a subgroup of mitochondrial encephalomyopathic diseases, the normally modified wobble base (a 2-thiouridine derivative) remains unmodified. Since wobble base modifications are essential for translational efficiency and accuracy, we used mitochondrial components to estimate the translational activity in vitro of purified tRNALys carrying the mutation and found no mistranslation of non-cognate codons by the mutant tRNA, but almost complete loss of translational activity for cognate codons. This defective translation was not explained by a decline in aminoacylation or lowered affinity toward elongation factor Tu. However, when direct interaction of the codon with the mutant tRNALys defective anticodon was examined by ribosomal binding analysis, the wild-type but not the mutant tRNALys bound to an mRNAribosome complex. We therefore concluded that the anticodon base modification defect, which is forced by the pathogenic point mutation, disturbs codon-anticodon pairing in the mutant tRNALys, leading to a severe reduction in mitochondrial translation that eventually could result in the onset of MERRF.

Original languageEnglish
Pages (from-to)4794-4802
Number of pages9
JournalEMBO Journal
Issue number17
Publication statusPublished - Sept 3 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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