Phenotypical expression and molecular genetics of the nt-3243 mutation in the mitochondrial tRNA(LEU(UUR)) gene

V. Petruzzella, M. Hirano, C. T. Moraes, S. Dimauro, E. Bonilla, E. A. Schon

Research output: Contribution to journalArticle

Abstract

The morphological and genetic characteristics of isolated muscle fibers from patients harboring an A->G mutation at nt-3243 in the mitochondrial tRNA(Leu(UUR)) gene have been analysed. This mutation is associated with two distinct disorders, namely, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS3243) and progressive external ophthalmoplegia (PEO3243). Morphologically, the main distinctive feature in PEO3243 muscle sections is the presence of a subset of ragged-red fibers (RRF) with no cytochrome c oxidase activity, a feature which is present only rarely in MELAS3243 muscle. By single fiber PCR analysis, we have found that the two disorders exhibit a distinctive pattern in muscle of the distribution of the nt-3243 mutation. Furthermore, we have provided evidence that the focal concentration of the nt-3243 mutation in single muscle fibers induces impairment of respiratory chain function.

Original languageEnglish (US)
Pages (from-to)177-183
Number of pages7
JournalBulletin of Molecular Biology and Medicine
Volume20
Issue number3-4
StatePublished - Dec 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Clinical Biochemistry

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