Abstract
Breeding tests of chimaeric male mice which were produced with the embryonic stem cells (F1/1) carrying the neomycin phosphotransferase (neo) gene indicated chimaerism in their germ lines. Fifty to 100% of fertile chimaeric mice derived from four F1/1 cell lines carrying the neo gene were germ line chimaeras and germ lines in most of them were taken possession of derivations of F1/1 cells completely. Southern blot hybridization or polymerase chain reaction analysis of genomic DNAs confirmed that F1 and F2 generation of germ line chimaeric mice were transmitted with the neo gene. Genetic analysis of offspring obtained by mating F2 transgenic mice with ICR mice identified homozygous mice. These results suggest that F1/1 cells can be utilized for the production of transgenic mouse.
