Figure 3
Only epiblast cells that contact the posterior part of the embryo become PGCs. (A) E5.75 Cerl:gfp embryo showing GFP expression exclusively in the AVE. (B) Cartoon depicting a transverse proximal section of a E5.75 Cerl:gfp embryo showing the anterior-posterior (A-P) and left-right (L-R) axes. (C) E5.75 Cerl:gfp embryo cut longitudinally through the L-R axis (red-dashed line in B) showing GFP expression in the AVE. (D) E5.75 embryo cut longitudinally through the L-R axis after 4 days culture stained for alkaline phosphatase-activity. Black arrow in D points to PGCs. Scale bar is 100 μm. (E) Quantification of the number or explant-pairs cut longitudinally through the L-R axis that exhibited PGCs after 4 days of culture in one explant-half (posterior), both explants-halves or in none of the explant-halves.