Fig. 1. Eda-A1 suppresses BMP activity in developing incisors. Whole-mount in situ hybridization analysis of ameloblastin expression in E15 incisors cultured with protein-releasing beads for 1 day. (A) Some endogenous expression of ameloblastin is present in explants cultured with a BSA bead. (B) Ameloblastin was strongly induced by a Bmp4-releasing bead. (C) BSA-releasing beads (small and blue) were placed at the same time with the Bmp4 bead (large and white). (D) Eda-A1 beads (blue) had no major effect on Bmp4-induced expression of ameloblastin when applied simultaneously with the Bmp4 bead (white). (E) BSA beads (blue) applied 6 hours before the Bmp4 bead (white) had no effect on ameloblastin expression. (F) Introduction of Eda-A1-releasing beads (blue) 6 hours before the BMP bead (white) strongly inhibited the induction of ameloblastin. (G) The endogenous expression of ameloblastin was reduced in the presence of Eda-A1 (compare with A).