Fig. 4. Integrin ß8 expression in E9.5 placenta tissue. (A-D) Sections of E9.5 placenta hybridized with integrin ß8 antisense (A,C,D) or sense (B) probes showing localization of integrin ß8 to most of placenta tissues, notably in the trophoblast giant cells (A), labyrinthine layer and spongiotrophoblast layer (C). In the yolk sac, integrin ß8 appears to be expressed specifically in the endoderm cells (D, arrow). sp, spongiotrophoblast layer; lb, labyrinthine layer. Scale bar: 200 µm in C; 50 µm in D.