Abstract
We found previously, using lacZ-transgenic mice, that mutation induction in UVB-exposed skin epidermis was suppressed at a higher dose range and saturated to a leveled mutant frequency (Ikehata and Ono, Mutat. Res., 508:41-47, 2002). This epidermal phenomenon of mutation induction suppression (MIS) to UVB genotoxicity would be a biological defensive response unidentified before. We also observed the MIS response in sunlight-exposed epidermis, and the saturated mutant frequencies reached there were more than twice of that seen in the UVB-irradiated (Ikehata et al., Mutat. Res., in press). We will report a study on wavelength-dependency of the MIS response using a monochromatic UV source. We will also show some data on a relation of apoptosis to MIS.
