Understanding the behavior of transgenes introduced into oocyte or embryos is essential for evaluating the methodologies for transgenic animal production. To date, many studies have reported the production of transgenic pig embryos with, however, low efficiency in environment of blastocyst production. The aim of present study was to determine the expression and duration of transgene transferred by intracytoplasmic sperm injection-mediated gene transfer (ICSI-MGT). Embryos obtained from the ICSI-MGT procedure were analysed for the expression of GFP and then for the transmission of the transgene. Briefly, fresh spermatozoa were bound to exogenous DNA after treatment by Triton X-100 and Lipofectin. When ICSI-MGT was performed using sperm heads with tails removed, the yield of blastocyst (25.3%), treated with Lipofectin (18.8%) and Triton X-100 (19.2%) were observed. Treatments of Lipofectin or Triton X-100 did not further improve the rates of blastocysts. Moreover, the apoptosis rates of embryos were obtained from the control and LIpofectin groups (8.7%, 9.7%, respectively), but were significantly higher in the Triton X-100 group (13.0%). Our results demonstrated that ICSI-MGT caused minimal damage to oocytes that could develop to full term. Moreover, the embryos derived by ICSI-MGT have shown prolonged exogenous DNA expression during preimplantation stage in vivo. However, more efforts will be required to improve the procedures of both sperm treatments cause of high frequency of mosaicisms.

INTRODUCTION
 MATERIALS AND METHODS
  1. In Vitro Maturation of Oocytes
  2. Sperm Collection and Treatments
  3. Intracytoplasmic Sperm Injection and Oocyte Activation
  4. Apoptosis Analysis and Cell Counting
  5. Embryo Transfer and Recovery
  6. Statistics
 RESULTS AND DISCUSSION
 REFERENCES

• Gi-Sun Im(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea)
• Jin-Ki Park(Dept. of Swine & Poultry Science, Korea National College of Agriculture and Fisheries, Jeonju 560-500, Korea)
• In-Sul Hwang(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea)
• Mi-Ryung Park(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea)
• Kyung-Woon Kim(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea)
• Chun-Gyu Park(CHO-A Biotechnology Research Institute, CHO-A Pharmaceutical Co., Ltd., Yeo-Ju 469-841, Korea)
• Joo-Hee Han(CHO-A Biotechnology Research Institute, CHO-A Pharmaceutical Co., Ltd., Yeo-Ju 469-841, Korea)
• NaRae Son(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea)
• Hak-Jae Chung(Animal Biotechnology Division, National Institute of Animal Science, Wanju 565-851, Korea) Correspondence