The low abundance of clonally expanded mitochondrial DNA point mutations in aged substantia nigra neurons.
Clonally expanded mitochondrial DNA (mtDNA) deletions accumulate with age in human substantia nigra (SN) and high levels cause respiratory chain deficiency. In other human tissues, mtDNA point mutations clonally expand with age. Here, the abundance of mtDNA point mutations within single SN neurons from aged controls was investigated. From 31 single cytochrome c oxidase normal SN neurons, only one clonally expanded mtDNA point mutation was identified, suggesting in these neurons mtDNA point mutations occur rarely, whereas mtDNA deletions are frequently observed. This contrasts observations in mitotic tissues and suggests that different forms of mtDNA maintenance may exist in these two cell types.
Reeve
Amy K
AK
Newcastle University Centre for Brain Ageing and Vitality, Institute for Ageing and Health, Newcastle University, UK.
Krishnan
Kim J
KJ
Taylor
Geoffrey
G
Elson
Joanna L
JL
Bender
Andreas
A
Taylor
Robert W
RW
Morris
Christopher M
CM
Turnbull
Doug M
DM
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008938:Mitosis; D009474:Neurons / Q000166:cytology; D017354:Point Mutation; D013378:Substantia Nigra / Q000166:cytology* / Q000378:metabolism*
D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV