Fig. 2. Expression of transgenic and endogenous FGF9. In family OVE1070, transgene expression was first detected in the dorsal presumptive RPE (rNR) at E10.5 by in situ hybridization using an SV40 riboprobe (A). At E11.5, the transgene remained expressed in the dorsal rNR and was also expressed in the posterior of the lens vesicle (LV) (B). By E12.5, transgene expression was turned off in the rNR and became restricted to the lens (C). In chimeric embryos (OVE1070: ROSA26) (D), clusters of ß-gal-positive cells (arrows) were present in the rNR, indicating that cells from ROSA26 mice (blue cells) were induced to become neural retinal cells by the transgenic FGF9 secreted from neighboring cells. During normal eye development (E,F), expression of endogenous Fgf9 was detected in the prospective neural retina but not in the prospective RPE at E10.0 (E) and E11.5 (F). Fgf9 is also expressed in the ventral (yellow arrow in E) but not dorsal (yellow arrowhead) region of the optic stalk. Abbreviations: D-V, dorsal-ventral orientation; L, lens; LP, lens pit; LV, lens vesicle; NR, neural retina; rNR, RPE-derived neural retina. Scale bars: 50 µm in A,B,D-F; 100 µm in C.
