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Mitochondrial and nuclear DNA base excision repair are affected differently by caloric restriction
Author(s) -
Stuart Jeff A.,
Karahalil Bensu,
Hogue Barbara A.,
SouzaPinto Nadja C.,
Bohr Vilhelm A.
Publication year - 2004
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.03-0890fje
Subject(s) - mitochondrial dna , base excision repair , dna glycosylase , uracil dna glycosylase , mitochondrion , caloric theory , ap site , dna repair , dna damage , nuclear dna , biology , oxidative phosphorylation , oxidative stress , dna , microbiology and biotechnology , chemistry , biochemistry , endocrinology , gene
Aging is strongly correlated with the accumulation of oxidative damage in DNA, particularly in mitochondria. Oxidative damage to both mitochondrial and nuclear DNA is repaired by the base excision repair (BER) pathway. The “mitochondrial theory of aging” suggests that aging results from declining mitochondrial function, due to high loads of damage and mutation in mitochondrial DNA (mtDNA). Restriction of caloric intake is the only intervention so far proven to slow the aging rate. However, the molecular mechanisms underlying such effects are still unclear. We used caloric‐restricted (CR) mice to investigate whether lifespan extension is associated with changes in mitochondrial BER activities. Mice were divided into two groups, receiving 100% (PF) or 60% (CR) of normal caloric intake, a regime that extends mean lifespan by ~40% in CR mice. Mitochondria isolated from CR mice had slightly higher uracil (UDG) and oxoguanine DNA glycosylase (OGG1) activities but marginally lower abasic endonuclease and polymerase γ gap‐filling activities, although these differences were tissue‐specific. Uracil‐ initiated BER synthesis incorporation activities were significantly lower in brain and kidney from CR mice but marginally enhanced in liver. However, nuclear repair synthesis activities were increased by CR, indicating differential regulation of BER in the two compartments. The results indicate that a general up‐regulation of mitochondrial BER does not occur in CR.