EN
The study was carried out in order to evolve, adopt and optimize the new system for preparation of nuclear recipient cells at different stages preceding the somatic cell nuclear transfer (SCNT) in pigs, including in vitro maturation (IVM) of oocytes. The system was applied to facilitate and accelerate the epigenomic reprogrammability for gene expression of donor cell nuclei that had been transplanted into cytoplasmic microenvironment of recipient oocytes and subsequently underwent the dedifferentiating and re-establishing the totipotent epigenetically conditioned status of their transcriptional activity during the preimplantation development of cloned embryos. The use of trichostatin A (TSA)-mediated epigenetic modulation of in vitro-maturing porcine nuclear recipient oocytes that had been pre-treated with R-roscovitine (R-RSCV) resulted in significantly increased blastocyst formation rate among the cloned embryos compared to the R-RSCV- and TSA-unexposed group (almost 44% vs. 26%).