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Photoreactivation and excision repair of thymine dimers in ultraviolet-irradiated cultured fish cells

Journal Article · · Radiat. Res.; (United States)
DOI:https://doi.org/10.2307/3575727· OSTI ID:6929214
It was confirmed by colony-formation assays that cultured fish cells (CAF-MM1) are more sensitive to ultraviolet light (uv) than mammalian cells (mouse L cells). To study the high sensitivity of the fish cells, direct assay of thymine dimers was made by two-dimensional paper chromatography. The ratio of thymine dimers to thymine (TT/T) immediately after uv irradiation was proportional to uv dose and was 0.04% per 10 J/m/sup 2/ of uv. Similar values were also obtained in the mouse L cells used for comparison. When CAF-MM1 cells were incubated in the dark after uv irradiation, the value of TT/T did not change for up to 48 hr; that is, excision of dimers could not be detected. Visible light illumination immediately after uv irradiation reduced the amount of thymine dimers and increased the cell survival of CAF-MM1 cells. The results indicated a close relation between photoreactivation of dimers and the fraction of cells surviving. About half the thymine dimers could be photoreactivated upon exposure to visible light immediately after uv irradiation, but only 18% after 24 hr.
Research Organization:
Univ. of Tokyo, Japan
OSTI ID:
6929214
Journal Information:
Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 90:3; ISSN RAREA
Country of Publication:
United States
Language:
English