DNA damage, photorepair, and survival in fish and human cells exposed to UV radiation

✍ Scribed by Farid E. Ahmed; Richard B. Setlow; Eleanor Grist; Neva Setlow

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 604 KB
• Volume: 22
• Category: Article
• ISSN: 0893-6692
• DOI: 10.1002/em.2850220105

✦ Synopsis

The effect of various wavelengths of UVB rodiation on the induction of cyclobutane pyrimidine dimers in fish cells and human fibroblasts and the repair of these lesions were studied using an UV-endonuclease to measure dimers (endonuclease sensitive sites) by sedimentation of radioactive DNA, by gel electrophoresis of unlabeled DNA, and by cell survival. The data show that fish cells have an efficient photoreactivation system at wavelength > 304 nm that reverses cytotoxicity and dimer formation after exposure to filtered sunlamp irradiation of a shorter wave-length (A > 290 nm). Shorter wavelengths in UVB (>304 nm) are more effective in photore-versa1 than longer ones (>320 nm). As a consequence, 5 0 4 5 % of dimers induced by these wavelengths in fish are photoreactivated while they are being formed. A maior cytotoxicological lesion is the cyclobutane pyrimidine dimers.

Cultured human fibroblasts do not possess such a repair system. These results indicate that sunlamp irradiation has wavelengths that both damage and repair DNA.