ABSTRACT
Microinjection of DNA is currently the most efficient delivery method for making transgenic animals, and in particular for making transgenic livestock. The production of transgenic animals by cytoplasmic injection of DNA potentially offers several advantages to pronuclear microinjection. The transgenic mice produced from cytoplasmic injection of polylysine/DNA mixtures had genotypic and phenotypic characteristics similar to those produced by pronuclear microinjection. As is the case for pronuclear delivery of DNA alone, the mechanism by which polylysine enables DNA integration is not known. Because both the tertiary and quaternary conformations of DNA fragments are greatly altered by polylysine alone, the polylysine/DNA complex may be a more favorable substrate for achieving integration in embryos from injection into the cytoplasm than purified DNA alone.
