The application of the restriction site mutation assay to the study of the induction of mutations in the tissues of rodents.

The restriction site mutation (RSM) assay has been developed as a methodology for the study of base changes induced in restriction enzyme recognition sequences. In principle, the RSM methodology may be used to the study mutation induction in any organ, of any species, for which DNA sequence information is available. This paper describes the analysis of the induction of base sequence changes in restriction enzyme recognition sites present in the p53 and alpha-haemoglobin genes of male mice exposed to 1-ethyl-1-nitrosourea. Our results demonstrate the induction of G-->A transitions and G-->T transversions in a number of restriction enzyme recognition sites (BamH1, Pst1, Ban1, Msp1, Alu1) in DNA extracted from a number of different tissues from animals harvested 2-7 days after exposure. The data presented indicates that the RSM methodology has considerable potential for development for the study of induced base changes in the endogenous genes of a variety of species.