A pathogenic point mutation reduces stability of mitochondrial mutant tRNA(Ile).

ABSTRACT: Point mutations in mitochondrial tRNA genes are responsible for individual subgroups of mitochondrial encephalomyopathies. We have recently reported that point mutations in the tRNA(Leu)(UUR) and tRNA(Lys) genes cause a defect in the normal modification at the first nucleotide of the anticodon. As part of a systematic analysis of pathogenic mutant mitochondrial tRNAs, we purified tRNA(Ile) with a point mutation at nucleotide 4269 to determine its nucleotide sequence, including modified nucleotides. We found that, instead of causing a defect in the post-transcriptional modification, a pathogenic point mutation in the mitochondrial tRNA(Ile) reduced the stability of the mutant tRNA molecule, resulting in a low steady-state level of aminoacyl-tRNA. The reduced stability was confirmed by exami

SUBMITTER: Yasukawa T 

PROVIDER: S-EPMC110767 | biostudies-literature | 2000 Oct

REPOSITORIES: biostudies-literature