Figure 7. Summary of Oct4 null phenotype and working model.
A) In normal embryos, Oct4 promotes survival of all three blastocyst lineages, facilitating transcription of components of multiple metabolic pathways, as well as lineage-specific, cell fate-determining transcription factors. B) In EPI cells, Oct4 induces expression of multiple genes, including signaling molecules such as Fgf4 that induce PE cell fate non cell-autonomously. In PE cells, Oct4 normally acts downstream of Mapk to promote expression of Sox17, Pdgfra, Gata4, Sox7, and eventually Gata6. In parallel, Mapk represses Nanog in an Oct4-independent manner in PE cells. Also in parallel, Oct4 represses expression of Cdx2 and other TE genes in all ICM cells.