Fig. 8. Model for the Fgf8- and Agrs-based signal exchange between neural and non-neural cells at the anterior neural plate border.

Fgf8 produced by the ANB cells induces the expression of Agrs in cells adjacent to the anterior non-neural ectoderm by mediating Ras-dva1 and Otx2. In turn, Agrs secreted by cells in the anterior non-neural ectoderm promote forebrain development through stimulation of both Fgf8 gene expression and Fgf8 protein signaling in the ANB cells.