Generation of genetically modified mice by spermatozoa transfection in vivo: Preliminary results

Mouse vas deferens were injected with a plasmid DNA encoding the GFP (Green Fluorescent Protein). The night after injection males were mated with norm al oestrus females, and the offspring were analyzed. From 53 newborns, 4 we re found positive by PCR for the GFP gene. In these positive animals, some tissues showed expression for GFP as evidenced by a strong green cytoplasmi c fluorescence. GFP expression was particularly patent in the liver (hepato cytes), kidney (renal corpuscle and tubules), abdominal wall, and lung. The se preliminary results indicate the possibility to use this method as a sim ple alternative procedure to create transgenic animals, and it could be esp ecially helpful in species in which the microinjection procedure is not fea sible. (C) 2000 Wiley-Liss, Inc.