Damage-induced recombination in the yeast Saccharomyces cerevisiae.

Prokaryotic and eukaryotic cells have developed a network of DNA repair systems that restore genomic integrity following DNA damage from endogenous and exogenous genotoxic sources. One of the mechanisms used to repair damaged chromosomes is genetic recombination, in which information present as a second chromosomal copy is used to repair a damaged region of the genome. In this review, I summarized what is known about the molecular and cellular mechanisms by which various DNA-damaging agents induce recombination in yeast. The yeast Saccharomyces cerevisiae has served as an excellent model organism to study the induction of recombination. It has helped to define the basic phenomenology and to isolate the genes involved in the process. Given the evolutionary conservation of the various DNA repair systems in eukaryotes, it is likely that the knowledge gathered about induced recombination in yeast is applicable to mammalian cells and thus to humans. Many carcinogens are known to induce recombination and to cause chromosomal rearrangements. An understanding of the mechanisms, by which genotoxic agents cause increased levels of recombination will have important consequences for the treatment of cancer, and for the assessment of risks arising from exposure to genotoxic agents in humans.