Low frequency of mtDNA point mutations in patients with PEO associated with POLG1 mutations
- 9 February 2005
- journal article
- Published by Springer Nature in European Journal of Human Genetics
- Vol. 13 (4) , 463-469
- https://doi.org/10.1038/sj.ejhg.5201341
Abstract
Mitochondrial myopathy in progressive external ophthalmoplegia (PEO) has been associated with POLG1 mutations. POLG1 encodes the catalytic subunit of polymerase and is the only polymerase known to be involved in mtDNA replication. It has two functionally different domains, one polymerase domain and one exonuclease domain with proofreading activity. In this study we have investigated whether mtDNA point mutations are involved, directly or indirectly, in the pathogenesis of PEO. Muscle biopsy specimens from patients with POLG1 mutations, affecting either the exonuclease or the polymerase domain, were investigated. Single cytochrome c oxidase (COX)-deficient muscle fibers were dissected and screened for clonally expanded mtDNA point mutations using a sensitive denaturing gradient gel electrophoresis analysis, in which three different regions of mtDNA, including five different tRNA genes, were investigated. To screen for randomly distributed mtDNA point mutations in muscle, two regions of mtDNA including deletion breakpoints were investigated by high-fidelity PCR, followed by cloning and sequencing. Long-range PCR revealed multiple mtDNA deletions in all the patients but not the controls. No point mutations were identified in single COX-deficient muscle fibers. Cloning and sequencing of muscle homogenate identified randomly distributed point mutations at very low frequency in patients and controls (POLG1 mutations.Keywords
This publication has 25 references indexed in Scilit:
- Structure-function defects of human mitochondrial DNA polymerase in autosomal dominant progressive external ophthalmoplegiaNature Structural & Molecular Biology, 2004
- ND5 is a hot-spot for multiple atypical mitochondrial DNA deletions in mitochondrial neurogastrointestinal encephalomyopathyHuman Molecular Genetics, 2003
- Novel POLG mutations in progressive external ophthalmoplegia mimicking mitochondrial neurogastrointestinal encephalomyopathyEuropean Journal of Human Genetics, 2003
- Mutations of mitochondrial DNA polymerase γA are a frequent cause of autosomal dominant or recessive progressive external ophthalmoplegiaAnnals of Neurology, 2002
- Active Site Mutation in DNA Polymerase γ Associated with Progressive External Ophthalmoplegia Causes Error-prone DNA SynthesisPublished by Elsevier ,2002
- Role of Adenine Nucleotide Translocator 1 in mtDNA MaintenanceScience, 2000
- Thymidine Phosphorylase Gene Mutations in MNGIE, a Human Mitochondrial DisorderScience, 1999
- Clonal expansion of mitochondrial DNA with multiple deletions in autosomal dominant progressive external ophthalmoplegiaAnnals of Neurology, 1996
- Cloning and Characterization of the Human Mitochondrial DNA Polymerase, DNA Polymerase γGenomics, 1996
- An autosomal dominant disorder with multiple deletions of mitochondrial DNA starting at the D-loop regionNature, 1989