FTFII-I expression at E8. A. Embryo and placenta (5 ×), B. Embryo at ED8, head region (16 ×), C. Placenta at ED8 (32 ×), D. Embryo, brain region (32×). TFII-I immunoreactivity is present in both embryo and placenta at ED8. A and B. Extra-embryonic membranes demonstrate extensive TFII-I immunoreactivity in trophectoderm (TR) derivatives, as well as in yolk sac (YS) and amniotic membrane (AM). C and D. Within the embryo, neural ectoderm (NE) as well as mesoderm (M) shows TFII-I immunoreactivity. Of note, much of the immunoreactivity appears cytoplasmic in localization. Abbr.: AC-Amniotic Cavity, AM-Amniotic Membrane, CS-Cardio-vascular System, D-Prospective Diencephalon, HM-Head Mesenchyme, M-Mesoderm, NE-Neural Ectoderm, NG-Neural Groove, SE-Surface Ectoderm, TD-Trophoectoderm Derivatives, YS-Yolk Sac.