A Regulatory Loop Involving PAX6, MITF, and WNT Signaling Controls Retinal Pigment Epithelium Development
Figure 3
Gene dose of Pax6 regulates dorsal RPE development in a hypomorphic Mitf mutant.
Sectioning and labeling was performed as for Figure 1. In contrast to single Mitfmi-ΔD/Mitfmi-ΔD mutants, there is dorsal RPE thickening in Pax6Sey-Neu/Pax6+; Mitfmi-ΔD/Mitfmi-ΔD mutants (arrows in B,E,H,K). Some cells in the thickened RPE are positive for CD138, a retinal progenitor marker (arrow in E), or TUJ1, a neuronal marker (arrow in K). Scale bar (A–C,G–I): 115 µm; (D–F,J–L): 90 µm. (M,N) Expression levels of the indicated RNAs in isolated RPE fractions based on quantitative RT-PCR (fold change relative to wild type). Results represent means and S.D. obtained from 3 biologically independent samples, each representing a pool of approximately 40 RPEs. Statistical significance of the results (see Experimental Procedures) is given for multiple pairwise comparisons.