The technique of SCNT is now well established but still remains inefficient. The in vitro development of SCNT embryos is dependent upon numerous factors including the recipient cytoplast and karyoplast. Above all, the metaphase of the second meiotic division (MII)　oocytes have typically become the recipient of choice. Generally high level of MPF present in MII oocytes induces the transferred nucleus to enter mitotic division precociously and causes NEBD and PCC, which may be the critical role for nuclear reprogramming. In the present study we investigated the in vitro development and pregnancy of White-Hanwoo SCNT embryos treated with caffeine (a protein kinase phosphatase inhibitor). As results, the treatment of 10 mM caffeine for 6 h significantly increased MPF activity in bovine oocytes but does not affect the developmental competence to the blastocyst stage in bovine SCNT embryos. However, a significant increase in the mean cell number of blastocysts and the frequency of pregnant on 150 days of White-Hanwoo SCNT embryos produced using caffeine treated cytoplasts was observed. These results indicated that the recipient cytoplast treated with caffeine for a short period prior to reconstruction of SCNT embryos is able to increase the frequency of pregnancy in cow.

ABSTRACT   MATERIALS & METHODS    In Vitro Oocyte Maturation    Caffeine Treatment and Parthenogenetic Activation of In Vitro Mature MII Oocytes    Oocyte Enucleation    Donor Cell Culture    Cell Fusion and Activation    Culture of Reconstructed Embryos    MPF Activity Assay    Statistical Analysis   RESULTS    MPF Activity at Different Stages of Oocyte Maturation    Determination of the Optimal Concentration of Caffein    Determination of the Optimal Period of Exposure to Caffeine    Development of NT Embryos Reconstructed using CaffeineTreated Oocytes as Cytoplast Recipients   DISCUSSION   REFERENCES

• Joon-Hee Lee(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea and Institute of Agriculture & Life Science, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 660-701, Korea)
• Hee-Gyu Lee(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Sang-Ki Baik(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Sang-Jin Jin(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Song-Yi Moon(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Hye-Ju Eun(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Tae-Suk Kim(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea)
• Hae-Geum Park(Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 600-701, Korea and Animal Genetic Resources Station, National Institute of Animal Science, Rural Development Administration, Namwon 590-832, Korea)
• Yeoung-Gyu Ko(Animal Genetic Resources Station, National Institute of Animal Science, Rural Development Administration, Namwon 590-832, Korea)
• Sung-Woo Kim(Animal Genetic Resources Station, National Institute of Animal Science, Rural Development Administration, Namwon 590-832, Korea)
• Soo-Bong Park(Animal Genetic Resources Station, National Institute of Animal Science, Rural Development Administration, Namwon 590-832, Korea) Corresponding author