Isoelectric focusing and electrophoresis combined as a method for defining new point mutations in the mouse.

Isoelectric focusing followed by electrophoresis is a method that allows the survey of the expression of an enormous number of genes in one organism when this method is used for separation of complex protein solutions from the tissue of the organism (protein-mapping method). This makes it possible to use this method for developing a test system aiming at the detection of newly induced or spontaneous point mutations in mammals. A large number of loci could be tested on a relatively small number of individuals. The protein-mapping method was used for the separation of mouse tissue extracts containing soluble proteins or total cell proteins. Several modifications of the method are described. The applicability of this method for defining genetic differences of proteins was demonstrated by an investigation of different strains of mice. Thereafter, a mutagenicity test was initiated with the protein-mapping method. Mice were treated with methyl-nitroso-urea as a potential mutagenic substance and the fetuses of the F1 generation were investigated. Preliminary results suggest that new point mutations were detected with this method.