(A) In situ hybridization analysis of Er71. PS, primitive streak; Bl, blood islands; Al, allantois; Am, amnion; A, anterior; P, posterior; D, dorsal; V, ventral (B, C) Er71 expression analysis. RNA obtained from differentiating ES cells (B) or various cell populations sorted from day 2.75 EBs (C) was used to examine Er71 expression. The value normalized against Gapdh is shown on the Y-axis.