In Vitro Culture of Mouse Embryos after Pronuclear Microinjection with sMTPGH Fusin Gene

The sheep metallothionein (sMT) pig growth hormone (PGH) gene was constructed, purified and microinjected into the pronucleus of fertilized mouse′s eggs. Then, the development capability of these transgenic embryos cultured in three different media was compared. In the experiment, the fertilized eggs overcame the 2 cell block and developed to blastocyst stage when cultured in the modified M16(mM16) medium. In addition, the mM16 that complemented with epidermal growth factor (EGF) further improved the blastocyst rates. The results showed that 12%, 68% and 90% of the microinjected embryos passed the 2 cell block and developed to 4 cell stage, and 0%, 20% and 43% of them developed to blastocyst stage in M16, mM16 and mM16+EGF media , respectively.Taurine may play an important role in overcoming the 2 cell block during embryo development.EGF is supposed to be involved in the elimination of the toxins came from the embryos or the media. The retained foreign gene was monitored by PCR in 57 blastocysts, 4 blastocysts were proved to be positive.The retention rate of foreign gene integrated in blastocyst was 7%. This method might provide a way to screen transgenic embryos in establishing transgenic farm animals.