The endodermal cells lie in the deepest layer of the hypoblast. (A) Confocal image of endodermal and mesodermal cells in Tg(sox17:EGFP) embryo at the 90% epiboly stage. Dextran-Alexa594 was injected into a Tg(sox17:EGFP) embryo at the one-cell stage. The endodermal cells, which have many filopodial processes, are yellowish green and mesodermal cells are red. (B) Reconstructed z-section at the level of the dashed line in A. The extra-embryonic YSL is also red. The endodermal cells occupy the space between the mesodermal cells and extra-embryonic YSL. (C) Schematic representation of B. YSL, yolk syncytial layer.
|