Mammalian mitochondrial endonuclease activities specific for ultraviolet-irradiated DNA

Alan E. Tomkinson, R. Thomas Bonk, Joon Kim, Neil Bartfeld, Stuart Linn

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)


Mitochondrial forms of uracll DNA glycosylase and UV endonuclease have been purified and characterized from the mouse plasmacytoma cell line, MPC-11. As in other cell types, the mitochondrial uracll DNA glycosylase has properties very similar to those of the nuclear enzyme, although in this case the mitochondrial activity was also distinguishable by extreme sensitivity to dilution. Three mitochondrial UV endonuclease activities are also similar to nuclear enzymes; however, the relative amounts of these enzyme activities in the mitochondria is significantly different from that in the nucieus. in particular, mitochondria contain a much higher proportion of an activity analogous to UV endonuclease III. Nuclear UV endonuclease III activity is absent from XP group D fibrobiasts and XP group D lymphoblasts have reduced, but detectable levels of the mitochondrial form of this enzyme. This residual activity diflers in its properties from the normal mitochondrial form of UV endonuclease III, however. The presence of these enzyme activities which function in base excision repair suggests that such DNA repair occurs in mttochondrla. Alternatively, these enzymes might act to mark damaged mitochondrial genomes for subsequent degradation.

Original languageEnglish
Pages (from-to)929-935
Number of pages7
JournalNucleic acids research
Issue number4
Publication statusPublished - 1990 Feb 25
Externally publishedYes

ASJC Scopus subject areas

  • Genetics


Dive into the research topics of 'Mammalian mitochondrial endonuclease activities specific for ultraviolet-irradiated DNA'. Together they form a unique fingerprint.

Cite this