Endogenous DNA damage and spontaneous mutagenesis in cultured mammalian cells.

This review describes the main molecular mechanisms of endogenous mutagenesis, with reference to the possible sources of the different DNA lesions, the types of mutation originated and the specific defense strategies employed by the cell. The analysis of mutations induced by mutagenic agents that mimic the effect of endogenous sources of damage is also considered, since it provides information on the possible effect of intracellular mutagens. Furthermore spontaneous mutational spectra of different target genes of mammalian cells are described and compared and the contribution of the different mutational sources is discussed.