Figure 9
From: Fgf-dependent otic induction requires competence provided by Foxi1 and Dlx3b
Model summarizing the early events upstream of otic induction. During gastrulation, Fgf signaling antagonizes Bmp signaling that activates the competence factors Foxi1 and Dlx3b-4b (green). Foxi1 is activated by BMP signaling in a direct manner whereas Dlx3b-4b requires an additional factor X. It is unknown whether Fgf signaling inhibits Bmp signaling at a transcriptional or translational level (?). The proper balance of Bmp and Fgf signaling during gastrulation promotes the positioning and size of the preotic region leading to the induction of otic fate as indicated by Pax8 and Pax2a expression (blue).