Experimental design for distinguishing the allelic origin of Oct4 mRNA in SCNT and fertilized embryos.

<p>(<b>A</b>) Enucleated C3H/HeN (for brevity, C3H) oocytes were transplanted with C57Bl/6J (for brevity, B6) cumulus cell nuclei to produce SCNT embryos, which were cultured in the presence of aphidicolin (Aph) or in normal medium, resulting in G1/S phase arrested pronuclear oocytes or in cleavage stages, respectively. Fertilized embryos were produced with intact C3H oocytes and B6 sperm and cultured the same way as the SCNT embryos. hpa: hours past activation. (<b>B</b>) Oct4 transcript from the C3H and B6 mouse strains can be distinguished by a restriction-enzyme-sensitive single nucleotide polymorphism (SNP). Oct4 transcript from C3H remains uncut (565 bp), while Oct4 transcript from B6 is cut (429 bp and 136 bp). If found positive for β-actin mRNA, embryos were then processed and analyzed individually.