Finding of bands of higher molecular weight than expected in three proteins in bovine preimplantation embryos

We report here the existence of bands of higher molecular weight after western blot analysis in three proteins – Skp1, p27 and IκBα in bovine preimplantation embryos. This finding is specific to preimplantation embryos (from the 2-cell stage to the blastocyst stage) and not differentiated fibroblast cells in which these bands were of expected molecular weight. We suggest that these bands of higher molecular weight represent a complex of proteins that are characteristic of preimplantation embryos.