Quantification of oxidative DNA modifications in mitochondria

Hegler, Jutta; Bittner, Detlef; Boiteux, Serge; Epe, Bernd

doi:10.1093/carcin/14.11.2309

Cited by 51 publications

(23 citation statements)

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“…Various mutagenic oxidative lesions have been measured in mtDNA (21), but most studies have focused on 8-oxoguanine. Despite a 20-fold increase in the level of this lesion in the mtDNA of OGG1-null mice (16), no evidence for mitochondrial dysfunction was found in these animals, suggesting that the functional impact of this lesion in mtDNA is low (49).…”

Section: Discussionmentioning

confidence: 99%

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Removal of Oxidative DNA Damage via FEN1-Dependent Long-Patch Base Excision Repair in Human Cell Mitochondria

Liu

Sung

et al. 2008

Molecular and Cellular Biology

189

185

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Repair of oxidative DNA damage in mitochondria was thought limited to short-patch base excision repair (SP-BER) replacing a single nucleotide. However, certain oxidative lesions cannot be processed by SP-BER. Here we report that 2-deoxyribonolactone (dL), a major type of oxidized abasic site, inhibits replication by mitochondrial DNA (mtDNA) polymerase ␥ and interferes with SP-BER by covalently trapping polymerase ␥ during attempted dL excision. However, repair of dL was detected in human mitochondrial extracts, and we show that this repair is via long-patch BER (LP-BER) dependent on flap endonuclease 1 (FEN1), not previously known to be present in mitochondria. FEN1 was retained in protease-treated mitochondria and detected in mitochondrial nucleoids that contain known mitochondrial replication and transcription proteins.

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Section: Discussionmentioning

confidence: 99%

“…ROS generate a variety of oxidative DNA lesions by reacting with most atoms of the DNA bases and the deoxyribose sugars (21). Some of the base lesions are confirmed to be repaired in mitochondria by BER (5).…”

mentioning

confidence: 99%

Removal of Oxidative DNA Damage via FEN1-Dependent Long-Patch Base Excision Repair in Human Cell Mitochondria

Liu

Sung

et al. 2008

Molecular and Cellular Biology

189

185

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“…The content of one oxidative product, 8-oxo-dG, has been reported to occur with a severalfold-higher frequency in mtDNA than in nuclear DNA and to increase with age (31,43). Although some studies have failed to observe a high steady-state level of 8-oxo-dG in mtDNA (11,12), DNA backbone damage produced by oxidative stress can be documented and is subject to repair (9,12). Many of these repairable lesions in mtDNA may be processed by a base excision repair (BER) mechanism that should be maintained to permit repair of the frequent spontaneous base loss that occurs in any DNA (23,24).…”

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confidence: 99%

Efficient Repair of Abasic Sites in DNA by Mitochondrial Enzymes

Pinz

Bogenhagen

1998

Molecular and Cellular Biology

178

144

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Mutations in mitochondrial DNA (mtDNA) cause a variety of relatively rare human diseases and may contribute to the pathogenesis of other, more common degenerative diseases. This stimulates interest in the capacity of mitochondria to repair damage to mtDNA. Several recent studies have shown that some types of damage to mtDNA may be repaired, particularly if the lesions can be processed through a base excision mechanism that employs an abasic site as a common intermediate. In this paper, we demonstrate that a combination of enzymes purified from Xenopus laevis mitochondria efficiently repairs abasic sites in DNA. This repair pathway employs a mitochondrial class II apurinic/apyrimidinic (AP) endonuclease to cleave the DNA backbone on the 5 side of an abasic site. A deoxyribophosphodiesterase acts to remove the 5 sugar-phosphate residue left by AP endonuclease. mtDNA polymerase ␥ fills the resulting 1-nucleotide gap. The remaining nick is sealed by an mtDNA ligase. We report the first extensive purification of mtDNA ligase as a 100-kDa enzyme that functions with an enzyme-adenylate intermediate and is capable of ligating oligo(dT) strands annealed to poly(rA). These properties together with preliminary immunological evidence suggest that mtDNA may be related to nuclear DNA ligase III.

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“…Damage to circular DNA such as the mitochondrial genome can be detected using repair enzymes followed by observation of changes in form (supercoiled to circular, etc.) (42,43). A fourth method, used since 1985 to measure damage for the purposes of repair but only recently to measure endogenous damage, is the enzymatic/Southern blot method, more commonly referred to as the gene specific repair assay (44,45).…”

Section: Methods Used For the Measurement Of Oxidative Dna Damagementioning

confidence: 99%

Mitochondria, oxidative DNA damage, and aging

Anson

Bohr

2000

AGE

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Protection from reactive oxygen species (ROS) and from mitochondrial oxidative damage is well known to be necessary to longevity. The relevance of mitochondrial DNA (mtDNA) to aging is suggested by the fact that the two most commonly measured forms of mtDNA damage, deletions and the oxidatively induced lesion 8-oxo-dG, increase with age. The rate of increase is species-specific and correlates with maximum lifespan.It is less clear that failure or inadequacies in the protection from reactive oxygen species (ROS) and from mitochondrial oxidative damage are sufficient to explain senescence. DNA containing 8-oxo-dG is repaired by mitochondria, and the high ratio of mitochondrial to nuclear levels of 8-oxo-dG previously reported are now suspected to be due to methodological difficulties. Furthermore, MnSOD -/+ mice incur higher than wild type levels of oxidative damage, but do not display an aging phenotype. Together, these findings suggest that oxidative damage to mitochondria is lower than previously thought, and that higher levels can be tolerated without physiological consequence.A great deal of work remains before it will be known whether mitochondrial oxidative damage is a "clock" which controls the rate of aging. The increased level of 8-oxo-dG seen with age in isolated mitochondria needs explanation. It could be that a subset of cells lose the ability to protect or repair mitochondria, resulting in their incurring disproportionate levels of damage. Such an uneven distribution could exceed the reserve capacity of these cells and have serious physiological consequences.

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Quantification of oxidative DNA modifications in mitochondria

Cited by 51 publications

References 0 publications

Removal of Oxidative DNA Damage via FEN1-Dependent Long-Patch Base Excision Repair in Human Cell Mitochondria

Removal of Oxidative DNA Damage via FEN1-Dependent Long-Patch Base Excision Repair in Human Cell Mitochondria

Efficient Repair of Abasic Sites in DNA by Mitochondrial Enzymes

Mitochondria, oxidative DNA damage, and aging

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