Absence of a pyrimidine dimer repair mechanism for mitochondrial DNA in mouse and human cells.

We have assayed the ability of mammalian cells to remove pyrimidine dimers from their mitochondrial DNA. The results indicate that pyrimidine dimers are not repaired for as long as 48 hr after UV irradiation. Furthermore, molecules containing pyrimidine dimers are unable to replicate and are simply diluted out in subsequent cell divisions.