Application of Green Fluorescent Protein as a Marker for Selection of Transgenic Mouse Embryos before Implantation

In this study, we evaluated the application of green fluorescent protein (GFP) from the jellyfish Aequorea victoria, for efficient selection of possible transgenic and non-mosaic mouse embryos after microinjection. We injected 353 one-cell mouse zygotes with a DNA fragment carrying Gfp gene under the control of b-actin gene promoter. Eighty-seven per cent (307 embryos) of the injected embryos survived after microinjection. The surviving embryos were cultured for an additional day and then analysed for detection of GFP expression using a standard fluorescein isothiocyanate (FITC) filter set attached to a microscope. In this analysis, 34 % of the two-cell stage embryos (37 embryos out of 108) were found to be GFP positive. Of these GFP-positive embryos, 8 embryos out of 37 (21%) were found to be non-mosaic as GFP expression was detected in all the blastomeres. Our results show that the successful use of GFP as a vital marker for detection of mosaic embryos holds promise for potential application of this technology as a selection tool in the generation of transgenic animals.