Figure 7

The otx2 / gbx1 interface plays an essential role in midbrain-hindbrain boundary development. (A) Lateral view of a chimeric embryo stained for fgf8. The red arrowhead indicates ectopic fgf8 expression. (B) Lateral view of a chimeric embryo stained for pax2.1. The red arrowhead indicates ectopic pax2.1 expression. (C) Lateral view of a chimeric embryo stained for eng2. The red arrowhead indicates ectopic eng2 expression. (A', B', C') Close-up of the ectopic patch before biotin staining and (A", B", C") after biotin staining (brown). For all the three genes, ectopic expression is induced in gbx1-overexpressing cells within the otx2 domain (red arrowheads). (D) Summary table of the transplanted cells' positions and marker induction. Clones localized in the forebrain never induced ectopic fgf8, pax2.1 or eng2 expression.