Figure 6

Sca-1 was expressed in the chorion of the mouse placenta at E8.5 (A; arrow). The inset in (A) is shown at higher magnification in (B) and from a serial section in (C), where protein expression is indicated by arrows. Controls in which no primary antibody was used showed no positive staining (not shown). Sca-1 was expressed in the labyrinth at E10.5 (D) and E16.5 (E). The inset in (E) shows Sca-1 expression (arrowhead, blue; ISH) in cytokeratin positive trophoblast of the labyrinth (brown; IHC). Epcam mRNA expression was also detected in the chorion and appeared to overlap with Sca-1 expression at E8.5 (F). At E10.5, Epcam expression was more broadly expressed in the labyrinth than Sca-1 (G, compare with D) but by E16.5, both Epcam mRNA and protein were appreciably reduced however still present in more cells in the labyrinth than Sca-1 (H,I, compare with E). ch, chorion; mes, embryonic mesoderm; lab, labyrinth. Scale bar = 100 um.