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XB-ART-15370
Mol Cell Biol 1998 Mar 01;183:1257-65. doi: 10.1128/MCB.18.3.1257.
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Efficient repair of abasic sites in DNA by mitochondrial enzymes.

Pinz KG , Bogenhagen DF .


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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 gamma 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.

???displayArticle.pubmedLink??? 9488440
???displayArticle.pmcLink??? PMC108838
???displayArticle.link??? Mol Cell Biol


Species referenced: Xenopus laevis
GO keywords: mitochondrial DNA repair

???displayArticle.disOnts??? MERRF syndrome [+]
???displayArticle.omims??? MITOCHONDRIAL MYOPATHY, ENCEPHALOPATHY, LACTIC ACIDOSIS, AND STROKE-LIKE EPISODES; MELAS
References [+] :
Aoufouchi, Expression of DNA ligases I and II during oogenesis and early development of Xenopus laevis. 1992, Pubmed, Xenbase