Control of MPF Activity of Recipient Oocytes and Subsequent Development and DNA Methylation of Somatic Cell Nuclear Transfer Bovine Embryos

We attempted to control the maturation promoting factor (MPF) activity and investigated the subsequent reprogramming of bovine somatic cell nuclear transfer (SCNT) embryos. Serum-starved adult skin fibroblasts were fused to enucleated oocytes treated with 2.5 mM caffeine or $150\;{\mu}M$ roscovitine. The MPF activity, nuclear remodeling patterns, chromosome constitutions and development of SCNT embryos were evaluated. Methylated DNA of embryos was detected at various developmental stages. The MPF activity was increased by caffeine treatment or reduced by roscovitine treatment (p<0.05). Blastocyst development was higher in the caffeine-treated groups (27.6%) than that of the roscovitine-treated group (8.3%, p<0.05). There was no difference in the apoptotic cell index among the three groups. However, the mean cell number of blastocysts was increased in the caffeine-treated group (p<0.05). Higher methylation levels were observed in the Day 3 embryos of the roscovitine-treated group (50.8%), whereas lower methylation levels were noted at Day 5 in the caffeine-treated group (12.5%, p<0.05). These results reveal that the increase in MPF activity via a caffeine-treatment creates a more suitable condition for nuclear reprogramming after SCNT.