title: Construction and characterization of a cell line deficient in repair of mitochondrial, but not nuclear, oxidative DNA damage.
abstract: Oxidative base lesions, such as 8-oxoguanine, accumulate in nuclear and mitochondrial DNAs under oxidative stress, resulting in cell death. However, it is not known whether only oxidative lesion accumulated in mitochondrial DNA is involved in such cell death. By introducing human cDNA encoding a nuclear form of 8-oxoG DNA glycosylase (hOGG1-1a) into immortalized mouse embryo fibroblasts lacking Ogg1 gene, we established a cell line which selectively accumulates 8-oxoguanine in mitochondrial DNA under oxidative stress. Selective accumulation of 8-oxoguanine in mitochondrial DNA in this cell line causes degradation of mitochondrial DNA followed by ATP depletion, mitochondrial membrane permeability transition, and Ca(2+) efflux, which in turn activates calpains to execute cell death. Knockdown of MUTYH which excises adenine opposite 8-oxoG in DNA prevents degradation of mitochondrial DNA and activation of calpain, thus suppressing the cell death induced by menadione.
authors.affiliation: Division of Neurofunctional Genomics, Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
authors.forename: Sugako
authors.initials: S
authors.lastname: Oka
authors.forename: Mizuki
authors.initials: M
authors.lastname: Ohno
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Nakabeppu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015139:Blotting, Southern; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D004249:DNA Damage; D045647:DNA Glycosylases / Q000502:physiology*; D004260:DNA Repair; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress
chemical_list: D004272:DNA, Mitochondrial; C024829:8-hydroxyguanine; D006147:Guanine; D000255:Adenosine Triphosphate; D045647:DNA Glycosylases; C485990:Ogg1 protein, mouse; C479058:oxoguanine glycosylase 1, human; D002154:Calpain; D002118:Calcium