Fig. 9.

τGFP expression in E17.5 eyes on 20 μ cryosections. (A–D) τGFP signal only (E–H) τGFP plus DAPI. (A, E) Line Y223 shows expression in corneal epithelium, lens epithelium, iris, and ciliary body (CB). In the retina strong expression is seen in the ganglion cell layer (GCL) including the retinal ganglion (RGC) and amacrine cells, with weak expression in a subset of cells in the neuroblast layer (NBL). The presence of GFP in the axons of the RGCs gives rise to the strong staining in the optic nerve (ON). (B, E) Expression in line Y001 is the same as for line Y223, with GFP signal in corneal epithelium, lens epithelium, iris/ciliary body and the GCL and a subset of cells in the NBL of the neural retina. (C, G) Expression in line Y001ΔDRR is severely reduced in comparison with Y001, with GFP signal remaining in the corneal epithelium and very weakly in the GCL and NBL, but absent from lens, ciliary body and the RGCs. (D, H) Line Y028 shows similar expression as Y001ΔDRR, but relatively stronger expression in a cell layer within the GCL, most likely to be amacrine cells, and in a subset of differentiating neuroblasts in the NBL (white arrowhead). Note that panels C, D, G and H required 20 times longer exposure time than panels A, B, E, F. CB, ciliary body, C, corneal epithelium, L, lens, GCL, ganglion cell layer, NBL, neuroblast layer, ON, optic nerve.