Genetic and Molecular Analysis of Dna Damage Repair and Tolerance Pathways

Radiation can damage cellular components, including DNA. Organisms have developed a panoply of means of dealing with DNA damage. Some repair paths have rather narrow substrate specificity (e.g. photolyases, which act on specific pyrimidine photoproducts in a specific type (e.g., DNA) and conformation (double-stranded B conformation) of nucleic acid. Others, for example, nucleotide excisio~ repair, deal with larger classes of damages, in this case bulky adducts in DNA. A detailed discussion of DNA repair mechanisms is beyond the scope of this article, but one can be. found in the excellent book of Friedberg et al. [1] for further detail. However, some DNA damages and paths for repair of those damages important for photobiology will be outlined below as a basis for the specific examples of genetic and molecular analysis that will be presented below.