UV-stimulated recombination in mammalian cells is not dependent upon DNA replication.

The ability of UV light to stimulate recombination between viruses in mammalian cells is well established. Here we provide evidence that UV can also stimulate recombination between irradiated plasmids transfected into mammalian COS-7 cells. As the plasmids used, pSVOcat and pRSVcat(amb38), are incapable of replication in mammalian cells it is likely that the stimulatory effect of UV on recombination is due to a direct effect on the DNA rather than a consequence of the accumulation of nicked and gapped DNA-replication intermediates.