Abstract
Exposure of ICR 2A frog [embryo] cells to 265, 289, 302 or 313 nm UV radiation caused a decrease in the MI [mitotic index] of the irradiated cells in a fluence-dependent fashion. Treatment of cells with PRL [photoreactivating light] immediately after UV-irradiation resulted in a smaller decrease in the MI, demonstrating that pyrimidine dimers played a role in the mitotic inhibition induced by these UV wavelengths. The effect of PRL on 313 nm-irradiated cells was much smaller than for the other wavelengths tested, indicating that non-dimer photoproducts were of importance in the mitotic inhibition induced by this UV wavelength.