Fig. 7

Fig. 7

Phenotypes of medaka embryos misexpressing Fgf8. Injection of Fgf8 mRNA and CMV:Fgf8 results predominantly in a strong eye/forebrain phenotype (A). In most cases, the forebrain is dramatically reduced, but more posterior structures appear normal (otic vesicle marked by an arrow). The midbrain appears dramatically expanded (arrowhead) and structures anterior to the midbrain became lost. (B and C) show examples of observed eye phenotypes after induction of the gfp:HSE:Fgf8 DNA at stage 14. (B2 and C2) gfp expression in the area encompassing the black square marks in the corresponding images (B and C). Embryos developing cyclopic eyes (B) exhibit misexpression not within the eye, but in the adjacent tissue (B2 dotted line indicates the border between the eye and the forebrain). Loss of one eye (C) correlated with misexpression on the same side of the embryo (C2 the dotted line demarcates gfp-positive and -negative cells), the other eye is marked by arrowheads. D and E show the embryo with the cyclopia phenotype (B) at a later embryonic stage (D) and a larval stage (E). An embryo induced at the two-somite stage (stage 19) exhibited reduced size of one eye marked by an arrowhead (F). A pigmentation phenotype in one eye (arrowhead) and an expanded otic vesicle (arrow) were seen for a larva induced during mid-gastrula (G). Ectopic otic vesicles were repeatedly observed, a magnification of such an embryo is shown in (H); the ectopic otic vesicle is marked by an arrow. Note that gfp, marking the Fgf8 misexpressing cells, is not seen within in the vesicle (H2); autofluorescing medaka cells are marked by an arrowhead. Abbreviations: cyc., cyclopic eye; od, oil droplet.