Fig. 6. FGF8b and FGF17b proteins differentially regulate genes in mouse brain explants. Beads soaked in BSA, mouse FGF8b or human FGF17b, as indicated, were placed in midbrain explants and cultured for 48 hours. Wholemount RNA in situ analysis was then performed with the indicated probes. FGF8b strongly induces Gbx2 (E), Spry1 (H) and En1 (K), and represses Otx2 (B); FGF17b weakly induces En1 (L) and Spry1 (I).