OCT4-GFP expression in SCNT and ICSI embryos (C3HxOG2).

To test the requirement of first round DNA replication and cell division for reprogramming, pronuclear oocytes at 6 hours post activation (hpa) were cultured in 2 µg/mL aphidicolin (aph) or in 5 µg/mL cytochalasin B (CB) until 96 hpa. In parallel, pronuclear oocytes were allowed to cleave and reach the blastocyst stage. To test the requirement of second round DNA replication and cell division for reprogramming, 2-cell embryos at 24 hpa were cultured in 2 µg/mL aph or in 5 µg/mL CB until 96 hpa and were compared with time-matched blastocyst-stage embryos. For each treatment and type of embryo, results are given as frequencies of embryos expressing GFP/embryos imaged. These frequencies, given as percent, were analyzed using chi-square test and applying the Bonferroni correction for multiple comparisons.a,b: different superscripts within same row indicate significant difference (chi-square test).n.p.: not performed.