Transfer of foreign DNA into the cells of developing mouse embryos by microprojectile bombardment

Mouse cells of developing embryos at the 2-4 cell, morula and blastocyst stages, were bombarded by high velocity tungsten microprojectiles. About 70% of developing embryos survived the bombardment. The general embryo structure did not change as a result of the bombardment. Penetration of the tungsten microparticles into the embryo cell nuclei was found at all stages being investigated, and tungsten particle localization on mitotic chromosomes was demonstrated. The total DNA of the mice born from the bombarded embryos was analyzed by dot-blot hybridization and PCR with post-hybridization. The most important results were obtained in experiments with blastocysts. In three cases of blastocyst bombardment, the presence of transferred plasmid DNA (pSV3-neo) was revealed. Transfected cells were shown to be located in the fetal membrane as well as in the embryo. The bombardment of mouse culture cells resulted in their transfection and the production of G418-resistant clones.