Repopulation of rho0 cells with mitochondria from a patient with a mitochondrial DNA point mutation in tRNA(Gly) results in respiratory chain dysfunction.
Familial hypertrophic ventricular cardiomyopathy has been demonstrated to be associated with a number of mitochondrial DNA (mtDNA) mutations. A fibroblast cell line carrying a mutation in its mtDNA at position 9997 in the gene encoding tRNA glycine was obtained from a patient with hypertrophic cardiomyopathy. To demonstrate that the etiology of this disease was a result of the mtDNA mutation, cybrid clones were constructed by fusion of enucleated patient skin fibroblasts to rho0 osteosarcoma cells. Clones carrying high levels of mutant mtDNA showed predominantly cytochrome c oxidase and complex I deficiency, as well as an elevated lactate/pyruvate (L/P) ratio, a biochemical marker characteristic of respiratory chain deficiencies. Pulse-labeling experiments demonstrated a strong negative correlation between the levels of newly synthesized mtDNA-encoded polypeptides and glycine content. These data suggest that the T9997C mutation in mtDNA is causative of respiratory chain dysfunction when present at high levels of heteroplasmy.
Raha
S
S
Department of Biochemistry, University of Toronto, Canada.
Merante
F
F
Shoubridge
E
E
Myint
A T
AT
Tein
I
I
Benson
L
L
Johns
T
T
Robinson
B H
BH
D015139:Blotting, Southern; D002312:Cardiomyopathy, Hypertrophic / Q000235:genetics; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics*; D004579:Electron Transport / Q000502:physiology*; D042963:Electron Transport Complex II; D014450:Electron Transport Complex III / Q000378:metabolism; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells; D019344:Lactic Acid / Q000378:metabolism; D008957:Models, Genetic; D009097:Multienzyme Complexes / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010641:Phenotype; D017354:Point Mutation; D019289:Pyruvic Acid / Q000378:metabolism; D011808:Quinone Reductases / Q000378:metabolism; D012353:RNA, Transfer, Gly / Q000235:genetics*; D013385:Succinate Dehydrogenase / Q000378:metabolism
D004272:DNA, Mitochondrial; D009097:Multienzyme Complexes; D012353:RNA, Transfer, Gly; D019344:Lactic Acid; D019289:Pyruvic Acid; D010088:Oxidoreductases; D042963:Electron Transport Complex II; D013385:Succinate Dehydrogenase; D011808:Quinone Reductases; D009245:NADH Dehydrogenase; D002950:Citrate (si)-Synthase; D014450:Electron Transport Complex III; D005998:Glycine