Non-radioactive in situ hybridization of porcine embryos: A method to detect and localize the expression of early developmental genes

In situ hybridization is a method commonly used for detection and cellular localization of gene transcription in mammalian embryos. During implantation, cells of the blastocyst synthesize paracrine signaling molecules in an appropriate manner, via alterations in trophoblast gene expression. We used a digoxigenin-labeled probe for detection of mRNA encoding the embryo isoform of porcine cytochrome P350 aromatase, the terminal enzyme in the estrogen biosynthetic cascade, to localize the cells in which transcription of this gene occurs in late preimplantation-stage porcine embryos. Trophectodermal cells stained positive, indicating that transcription of the embryo aromatase isoform-encoding gene is active in these cells. Similar methods could be used to localize the expression of other early developmental genes in preimplantation porcine embryos.