Fig. 4. (A) The effect of inhibition of Shh activity by anti-Shh (5E1) antibody addition during GT formation. GTs from 12.5 dpc embryos (A) were cultured for 96 hours with 5E1 antibody (C) or with control antibody (B). The region above the line corresponds to GT (A). GT formation was retarded by 5E1 antibody application but not with control antibody. Reduced cell proliferation of anti-Shh antibody treated GTs is shown by a graph (D; control treated cell number is shown as 100%). Cultures of 11.5 dpc derived GTs showed more prominent reduction. Scale bar: 250 µm in A-C.