Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2005 May 17;102(20):7127-32. Epub 2005 May 3.

Specific correlation between the wobble modification deficiency in mutant tRNAs and the clinical features of a human mitochondrial disease.

Author information

1
Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

Abstract

Mutations in mtDNA are responsible for a variety of mitochondrial diseases, where the mitochondrial tRNA(Leu(UUR)) gene has especially hot spots for pathogenic mutations. Clinical features often depend on the tRNA species and/or positions of the mutations; however, molecular pathogenesis elucidating the relation between the location of the mutations and their leading phenotype are not fully understood. We report here that mitochondrial tRNAs(Leu(UUR)) harboring one of five mutations found in tissues from patients with symptoms of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) (A3243G, G3244A, T3258C, T3271C, and T3291C) lacked the normal taurine-containing modification (5-taurinomethyluridine) at the anticodon wobble position. In contrast, mitochondrial tRNAs(Leu(UUR)) with different mutations found in patients that have mitochondrial diseases but do not show the MELAS symptoms (G3242A, T3250C, C3254T, and A3280G) had the normal 5-taurinomethyluridine modifications. These observations were made by using a modified primer extension technique that can detect the modification deficiency in the extremely limited quantities of mutant tRNAs obtainable from patient tissues. These results strongly suggest deficient wobble modification could be a key molecular factor responsible for the phenotypic features of MELAS, which can explain why the different MELAS-associated mutations result in indistinguishable clinical features.

PMID:
15870203
PMCID:
PMC1129107
DOI:
10.1073/pnas.0500563102
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center