ULTRAVIOLET-INDUCED DNA-DAMAGE AND ITS PHOTOREPAIR IN TAIL FIN CELLS OF THE MEDAKA, ORYZIAS-LATIPES

To study UV-induced damage and its photorepair in vivo, endonuclease-s ensitive sites (ESS) induced by UV irradiation in the DNA of the tail fin of the Medaka, Oryzias latipes, were examined. Isolated fins were irradiated with UV-B, but no ESS were detected after increasing doses of UV-B up to 500 J/m2. Then fins were irradiated with UV-B and fin ce lls were dissociated by treatment with trypsin and EDTA. Ultraviolet-B -induced ESS were detected in the epithelial cells near the tissue sur face but not in the inner cells. The capacity for photorepair of both inner and outer epithelial cells and cells in fin ray was the same and was higher than that for a line of cultured cells, OL32.