Fig. 5. E-cadherin expression in clustered PGC precursors at base of nascent allantois. Lateral view of embryos at (A-D) mid-streak (E6.75), (E-H) mid- to late streak (E7.0), and (I-L) early allantoic bud (E7.25) stage with anterior to left. (A-D) Oct4-GFP (A) and E-cadherin (B) expression was slightly and obviously lower in the distal portion of extra-embryonic mesoderm (dotted line). Arrows indicate boundary of epiblast and extra-embryonic mesoderm; exee, extra-embryonic ectoderm; exem, extra-embryonic mesoderm; epi, epiblast; ve, visceral endoderm. (E-H) Cells expressing intense GFP (E, solid line) form a cluster at the apical tip of the E-cadherin-expressing region (F) of extra-embryonic mesoderm. (I-L) Committed PGCs expressing PGC7 (I) dispersed in the most distal region in E-cadherin-expressing extra-embryonic mesoderm (J). (C,G,K) TOTO-3 staining of nuclei and (D,H,L) merged images. Scale bar: 50 µm (A-D,I-L) and 25 µm (E-H).