Mitochondrial DNA copy number - but not a mitochondrial tandem CC to TT transition - is increased in sun-exposed skin.
Mitochondrial DNA (mtDNA) mutations are causatively associated with photo-ageing and are used as biomarkers of UV exposure. The most prominent mitochondrial mutation is the common deletion (CD), which is induced in many tissues by oxidative stress. More photo-specific mutations might be CC to TT tandem transitions which arise from UV-induced cyclobutane pyrimidine dimers. As nucleotide excision repair is absent in mitochondria, this DNA damage can presumably not be repaired resulting in high mitochondrial mutation levels. Here, we analysed levels of the CD, a mitochondrial and a chromosomal tandem transition in epidermis and dermis from exposed and less UV-exposed skin. We also analysed mtDNA copy number, for which changes as a result of oxidative stress have been described in different experimental settings. Whereas mitochondrial tandem transition levels were surprisingly low with no discernible correlation with UV exposure, mtDNA copy number and CD were significantly increased in UV-exposed samples.
Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, Sigmaringen, Germany.
Daniel
D
Gebhard
Bettina
B
Mahler
Katja
K
Matt
Katharina
K
Burger
Jörg
J
Bergemann
D000005:Abdomen; D000368:Aged; D000375:Aging / Q000235:genetics / Q000528:radiation effects*; D001483:Base Sequence / Q000528:radiation effects*; D015415:Biomarkers; D003596:Cytosine; D056915:DNA Copy Number Variations / Q000528:radiation effects*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005546:Forehead; D006801:Humans; D009333:Neck; D011740:Pyrimidine Dimers / Q000528:radiation effects*; D017384:Sequence Deletion / Q000528:radiation effects*; D012867:Skin / Q000528:radiation effects*; D013472:Sunlight / Q000009:adverse effects*; D013941:Thymine; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D015415:Biomarkers; D004272:DNA, Mitochondrial; D011740:Pyrimidine Dimers; D016159:Tumor Suppressor Protein p53; D003596:Cytosine; D013941:Thymine
CC to TT transition; common deletion; mitochondrial DNA; mitochondrial DNA copy number; photo-ageing biomarker