Differential gene and protein expression in pig nuclear transfer extraembryonic membranes and blastocyst stage embryos

The following experiments compared the efficiency of three fusion/activation protocols following somatic cell nuclear transfer (NT) with porcine fetal fibroblasts transfected with enhanced green fluorescent protein driven by the chicken beta-actin/rabbit beta-globin hybrid promoter (pCAGGEGFP). The three protocols included electrical fusion/activation (NT1), electrical fusion/activation followed by treatment with a reversible proteasomal inhibitor MG132 (NT2) and electrical fusion in low Ca followed by chemical activation with thimerosal/dithiothreitol (NT3). Data were collected at days 6, 12, 14, 30 and 114 of gestation. Fusion rates, blastocyst-stage mean cell numbers, recovery rates and pregnancy rates were calculated and compared between protocols. Fusion rates were significantly higher for NT1 and NT2 compared to NT3 (p<0.05). There was no significant difference in mean cell number. Pregnancy rate for NT2 was 100% (n=19) at all stages collected and was significantly higher than NT1 (71.4%,n=28; p<0.05), but was not significantly higher than NT3 (82.6%,n=23; p<0.15). Recovery rates were calculated based