Receptor-mediated transport of foreign DNA into preimplantation mammalian embryos

Mouse and rabbit preimplantation embryos with intact zona pellucida were in cubated for 3 hr with DNA-carrying constructs containing insulin as an inte rnalizable ligand: (insulin-polylysine)-DNA and (insulin-polylysine)-DNA-(s treptavidin-polylysine adenovirus). Video-intensified microscopy demonstrat ed that the constructs penetrated the zona pellucida and accumulated in the blastomere perinuclear space. The percentage of blastocysts formed was abo ut 70% after incubation of zygotes and two-cell embryos with the constructs . Foreign DNA was detected after 51 hr in 80% of rabbit embryos and after 9 6 hr in 73% of mouse embryos. Inclusion of various adenoviruses into the co nstruct improved foreign DNA preservation in early embryos. Blot hybridizat ion revealed genome-integrated foreign DNA in 12- and iii-day mouse embryos and in a newborn. Thus, the ligand-mediated mechanism can be employed for introducing foreign genetic material into early mammalian embryos; insulin provides for delivery inside the cell and to the nucleus, while adenoviruse s ensure release from endosomes. (C) 1999 Wiley-Liss, Inc.