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The effect on mitochondrial function of the tRNA Ser(UCN)/COI A7445G mtDNA point mutation associated with maternally‐inherited sensorineural deafness
Author(s) -
Hyslop Serena J.,
James Andrew M.,
Maw Marion,
FischelGhodsian Nathan,
Murphy Michael P.
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700202971
Subject(s) - mitochondrial dna , point mutation , biology , mutation , mitochondrion , genetics , transfer rna , human mitochondrial genetics , gene , rna
An A to G point mutation at nucleotide position 7445 in the mitochondrial DNA genome is associated with maternally‐inherited sensorineural deafness in two separate human pedigrees. To determine whether this point mutation [tRNASer(UCN)/COI A7445G] led to sensorineural deafness by affecting cellular energy metabolism we investigated the bioenergetic function of mitochondria in lymphoblastoid cultures established from these patients. Even though essentially all of the mitochondrial DNA in these cells contained the mutation at nucleotide position 7445, there was no effect on a number of mitochondrial bioenergetic functions (mitochondrial content, membrane potential in both intact and digitonin‐permeabilised cells, cellular ATP/ADP ratios and respiratory enzyme activity) when compared with control cells. The implications of these findings for both the aetiology of the sensorineural deafness associated with the A7445G mtDNA mutation, and the role of bioenergetic defects in mitochondrial DNA diseases in general, are discussed.