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Fig. 1. Expression of etv1 in the developing Xenopus laevis eye. Etv1 is detected by whole mount in situ hybridization during optic vesicle evagination (A, anterior view – bracket; inset, lateral view – arrow), in the pre-neurogenic optic vesicle (B, anterior view – bracket; inset, lateral view – arrow), and during the initial stages of retinal neurogenesis, (C and D, lateral view). By stage 29–30, etv1 is only expressed in the developing lens vesicle (E, lateral view – arrowhead). In situ hybridization on sections shows etv1 is most highly expressed in the ventral stalk and ventral optic vesicle at stage 24, with weaker expression in the neuroepithelium of the central to dorsal optic vesicle, and overlying surface ectoderm (F). At stage 28, etv1 is expressed throughout the retinal neuroepithelium and overlying surface ectoderm (G). At stage 29–30, the developing lens vesicle is strongly labeled, while there is no detectable expression of etv1 in the developing neural retina (H). At the end of embryonic retinal neurogenesis, etv1 is expressed in the photoreceptors of the outer nuclear layer but is absent from the rest of the central retina and also from progenitors in the ciliary marginal zone (I). Abbreviations: ov, optic vesicle; e, eye; lv, lens vesicle; se, surface ectoderm; ne, neuroepithelium; os, optic stalk; nr, neural retina; cmz, ciliary marginal zone; onl, outer nuclear layer. |
