Abstract
Radioadaptive response is a biological defense mechanism that is induced by low-dose ionizing irradiation for cellular resistance to the genotoxic effects of subsequent irradiation. The response is the acquisition of resistance to the induction of mutation, chromosome aberraion, and cell killing by ionizing radiation. We have shown that the radioadaptive response is mediated through the pathways involving protein kinase C and p38 mitogen-activated protein kinase. However, its molecular mechanism is still largely elusive. We examined mutations induced by ionizing radiation with or without radioadaptive response at the Hprt locus in mouse m5S cells. We analyzed the Hprt gene in 6-thioguanine-resistant mutants by amplification of all the nine exons of the mouse Hprt gene. Our results showed that the proportion of partial deletions was much higher in mutants isolated from the pre-exposed radioadaptive culture than in non-primed irradiated culture. [J Radiat Res 44:389-390 (2003)]
