A SHUTTLE VECTOR SYSTEM FOR STUDYING IONIZING RADIATION-INDUCED MUTAGENESIS IN MAMMALIAN-CELLS

A shuttle vector system was developed to quantitate and analyze ionizi ng radiation-induced mutation in mammalian host cells, COS-1 and CV-1. The shuttle vector pSV2-lacY, which was constructed to detect both po int mutations and deletions, was irradiated in vitro with Co-60 gamma rays before introduction into unirradiated host cells. The plasmid was then isolated and reintroduced into HB101 (lacY-) bacterial host cell s for identification of mutated lacY marker genes. Gamma-irradiation p roduced a decrease of the survival (recovery) and an increase of mutat ion of the shuttle vector. The mutated shuttle vector molecules were e xamined for structural changes by means of restriction endonuclease di gestion and agarose gel electrophoresis. A dose dependent increase was observed in the percentages of gross alteration events of total mutat ions in mammalian host. This system will be useful for studies of ioni zing radiation-induced mutagenesis.