Comparison of bioluminescence from bovine and mouse embryos after pronuclear microinjection with the firefly luciferase gene

Bioluminescence from pre-implantation bovine and mouse embryos after micro-injection of a firefly luciferase cDNA construct into their pronuclei were examined and compared using an imaging photon counting system, as a first step in evaluating the applicability of this luminescent marker for noninvasive selection of transgenic bovine embryos. Following injection of the gene construct, the bovine zygotes showed no notable impairment of their development in vitro. Light emission was also observed in the bovine embryos, but the rate was extremely low, and significantly lower (p < 0.01) than that of mouse embryos (0.4 versus 4.8%). In the future, integration of this gene construct into the genome of bioluminescent bovine embryos, together with its ability to be expressed in the offspring obtained and transmitted to the next generation, should be studied further.