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Mitochondrial DNA background modifies the bioenergetics of NARP/MILS ATP6 mutant cells.
- Source :
-
Human molecular genetics [Hum Mol Genet] 2010 Jan 15; Vol. 19 (2), pp. 374-86. Date of Electronic Publication: 2009 Oct 29. - Publication Year :
- 2010
-
Abstract
- Mutations in the mitochondrial DNA (mtDNA) encoded subunit 6 of ATPase (ATP6) are associated with variable disease expression, ranging from adult onset neuropathy, ataxia and retinitis pigmentosa (NARP) to fatal childhood maternally inherited Leigh's syndrome (MILS). Phenotypical variations have largely been attributed to mtDNA heteroplasmy. However, there is often a discrepancy between the levels of mutant mtDNA and disease severity. Therefore, the correlation among genetic defect, bioenergetic impairment and clinical outcome in NARP/MILS remains to be elucidated. We investigated the bioenergetics of cybrids from five patients carrying different ATP6 mutations: three harboring the T8993G, one with the T8993C and one with the T9176G mutation. The bioenergetic defects varied dramatically, not only among different ATP6 mutants, but also among lines carrying the same T8993G mutation. Mutants with the most severe ATP synthesis impairment showed defective respiration and disassembly of respiratory chain complexes. This indicates that respiratory chain defects modulate the bioenergetic impairment in NARP/MILS cells. Sequencing of the entire mtDNA from the different mutant cell lines identified variations in structural genes, resulting in amino acid changes that destabilize the respiratory chain. Taken together, these results indicate that the mtDNA background plays an important role in modulating the biochemical defects and clinical outcome in NARP/MILS.
- Subjects :
- Cell Respiration
Cells, Cultured
DNA, Mitochondrial metabolism
Humans
Leigh Disease genetics
Leigh Disease metabolism
Mitochondrial Proton-Translocating ATPases metabolism
Molecular Sequence Data
Retinitis Pigmentosa genetics
Retinitis Pigmentosa metabolism
DNA, Mitochondrial genetics
Energy Metabolism
Leigh Disease enzymology
Mitochondrial Proton-Translocating ATPases genetics
Mutation
Retinitis Pigmentosa enzymology
Subjects
Details
- Language :
- English
- ISSN :
- 1460-2083
- Volume :
- 19
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Human molecular genetics
- Publication Type :
- Academic Journal
- Accession number :
- 19875463
- Full Text :
- https://doi.org/10.1093/hmg/ddp503