Pluripotent-related gene expression analyses in single porcine recloned embryo

The developmental ability among embryos produced by three different techniques were examined: there were no significant differences in the developmental rate in porcine embryos produced by in vitro fertilization (IVF) and first generation of somatic cell nucleus transfer (SCNT), but the developmental rate dropped sharply at the 2- to four-cell stage in recloned (second generation of SCNT) embryos. In most recloned embryos, Oct4 and Klf4 were under-expressed at all stages, whereas Sox2 and Nanog were over-expressed at the two-cell stage. In contrast, Nanog was absent in IVF and SCNT embryos at the two-cell stage. The recloned embryos were treated with valproic acid to enhance developmental capacity and this led to an increase in the rate of blastocyst formation and total cell number compared with the findings for untreated recloned embryos (29.8 vs. 12.4 %, 39 vs. 25, respectively, p < 0.05).