X-RAY-RADIATION-INDUCED AND ULTRAVIOLET-RADIATION-INDUCED MUTATIONS IN MUTA(TM) MOUSE

To evaluate the usefulness of the transgenic Muta(TM) mouse for invest igating radiation-induced mutations in vivo, we have examined the effe cts of whole-body X irradiation and compared them to the effects of ul traviolet light. The spontaneous mutation frequencies in young adults were about 7 x 10(-5) in the spleen, liver and skin. The mutation freq uencies 1 week after a lethal dose of X radiation (8 Gy) were 3.2, 2.6 and 2.7 times the spontaneous levels in the spleen, liver and skin, r espectively. When the skin was irradiated with 10 kJ m(-2) of UVB, the mutation frequency increased about 6 times. The mutation frequencies induced by an acute dose of 4 Gy or by a fractionated dose of 11.7 Gy (0.15 Gy x 78 times, 3 times/week) in the spleen and liver were less t han 2-fold the spontaneous levels at 16 weeks after irradiation. A com parison of X and UV radiation was also conducted with cultured cells d erived from the mouse embryo. UVC of 5 3 m(-2) raised the mutation fre quency to 15 times that of unirradiated cells, while 10 Gy X rays rais ed it 2.6 times. The findings indicate that the Muta(TM) mouse is less sensitive to X-ray-induced mutation than UV-induced mutation. (C) 199 7 by Radiation Research Society.