Fig. 6. pPax2^Pax6 transgenic mice develop ectopic Mitf-positive RPE. (A) Construct used to establish the transgenic mouse line pPax2^Pax6. A Pax2-genomic sequence (5 kb) driving expression in the optic nerve was coupled to full-length Pax6 cDNA (Schwarz et al., 2000). Bright-field photos (B,D,F,H) and immunohistochemical detection of Mitf (C,E,G,I) of 12 µm cryosections of E14.5 wild-type (B-E, wt) and transgenic (F-I, pPax2^Pax6) eyes. Mitf is confined mainly to the iris in the wild-type (C, ir) and transgenic eye (G). Higher magnifications reveal that the ectopic RPE on the transgenic optic nerve is Mitf positive (I, arrows). Arrows in G indicate the ectopic Mitf⁺ RPE on the optic nerve; arrowheads in E indicate the endogenous Mitf expression in the RPE. ir, iris; le, lens; nr, neural retina; on, optic nerve; rpe, retinal pigmented epithelium.