Fig. 1. Mitf is ectopically expressed in the Chx10^or-J/or-J NR. (A) In the eye of an E10.5 wild-type (+/+) embryo, Mitf mRNA is present only in the presumptive RPE (arrow). (B) In an E10.5 Chx10^or-J/or-J (J/J) mutant eye, Mitf is expressed normally in the presumptive RPE (arrow), and ectopically in the NR (arrowhead). (C) By E13.5, Mitf is localized to the RPE and presumptive ciliary margin (arrow) in a wild-type embryo. (D) E13.5 Chx10^or-J/or-J animals continue to misexpress Mitf in the NR (arrowhead). In addition, the presumptive ciliary margin domain (arrow) is expanded, as evidenced by a larger area of increased Mitf expression. (E) Mitf protein levels mirror the RPE and presumptive ciliary margin (arrow) Mitf mRNA expression domains in a wild-type E13.5 embryo. (F) Mitf protein is synthesized in the E13.5 Chx10^or-J/or-J NR (arrowhead) and the enlarged presumptive ciliary margin region can also be clearly identified (arrow). Scale bars: 25 µm in A,B,D; 32 µm in C; 50 µm in E,F.