Ultraviolet-Induced Damage and Its Repair in Human DNA

Electromagnetic radiation of appropriate wavelength and intensity can induce damage in cellular macromolecular structures. Ultraviolet (UV) radiation can, for example, damage many cellular structures, including membranes, protein, RNA, and, of course, DNA. Almost all cells, including human cells growing in tissue culture, show a striking lowering of viability after moderate doses of UV irradiation. There is evidence suggesting that damage to DNA is the primary event responsible for UV-induced cell degeneration and death (1–3). Although cause and effect has not been definitely established, a number of experimental correlations support the theory that UV-induced DNA pyrimidine dimers represent one of the principal causative agents in the death and mutation of mammalian cells. Certainly, the identification of dimers as inactivating agents in human cells has provided us with the best insight available into an understanding of the role of cellular DNA repair processes in environmental carcinogenesis.