• Korean Journal of Animal Reproduction
• /
• v.26 no.3
• /
• pp.205-214
• /
• 2002

There are many methods to introduce exogenous DNA into embryo to produce transgenic animals. Exogenous gene can be integrated into oocyte by sperm vector. In this study, sperm was used as a vector for a transgene, which is encoding enhanced green fluorescent protein (EGFP). The objective of this study was to investigate the expression of exogenous gene in bovine embryos after injection of spermatozoa cocultured with EGFP DNA fragment. Spermatozoa were plunged into liquid nitrogen and thawed several times or shook in 0.2% Triton X-100 to remove sperm membrane followed by DTT treatment. The injected oocytes were co-cultured with vero cells in CR1aa, and expression of EGFP gene was observed under fluorescent microscope. Blastocyst formation rates of oocytes injected with sperm treated with DTT, DTT-freezing or DTT-Triton X-100 were 34.7, 39.4 and 31.9%, respectively. The rates of EGFP expression in oocytes injected with 54 ng DNA after DTT-treated, DTT-freezing and DTT-Triton X-100-treated sperm were 0, 19.1 and 13.9%. On the other hands, expression rate of oocytes injected with sperm cocultured with 13.5, 27 and 63.5 ng of EFGP DNA were 6.7, 9.0 and 5.1%, respectively. When intact sperm was mixed with 63.5 ng/${mu}ell$ EGFP DNA fragment, and then electroporated before injection, the expression rate of injected oocyte was 2%. Unexpectedly, electro-poration could not increase the expression rate. These results suggest that sperm can be used as a transgene vector, even if the efficiency was low (19.1%).