Hypersensitivity for gene mutation induction following X-ray exposure during the gastrula stage of development in the mouse.

Abstract

The sensitivity of the mouse gastrula embryonic stage for radiation induced mutations was studied using pUR288 transgenic reporter mice. 7.5 days old gastrula stage embryos were irradiated with 1Gy of X-rays followed by mutation analysis of liver, bone marrow, testis, kidney, brain and intestine 6 weeks later in surviving offspring. In all organs, increases in mutation frequencies were observed with in the irradiated animals a clear evidence for clonal expansion of mutation carrying cells. On a per Gy basis the gastrula stage showed with respect to the pUR288 system the highest mutation rate so far recorded in the literature suggesting a higher radiosensitivity of this phase of development compared to later embryonic and adult stages.