[The ballistic transfection of mammalian cells in vivo]

The method of ballistic transfection initially proposed for genetic transformation of plants was used for animal cells in vitro and in situ. The method consists in bombarding the transfected cells with microparticles of heavy metals carrying foreign DNA. Having penetrated in the cell nucleus, the microparticles transport the introduced gene. Successful genetic transformation of the cultured mouse cells and fish embryos was realized and this allowed to study mammalian cells in situ. The studies performed allowed us to demonstrate expression of the reporter genes of chloramphenicol acetyltransferase, galactosidase and neomycin phosphotransferase in the mouse liver, mammary gland and kidney explants, in the liver and cross-striated muscle of mouse and rat in situ and in developing mouse embryos at the stages of two-cell embryo, morula and blastocyst. All these genes were introduced by ballistic transfection. In the liver and cross-striated muscle the transgene activity was found within two-three months after transfection. Thus, the ballistic introduction of the foreign genes in the cells in situ was demonstrated and this opens possibilities for the use of this method in gene therapy. Methodical aspects of the bombarding and transfection are considered in detail and the published data on transfection and genetic transformation of mammalian cells are discussed.