FIGURE 5.

Pax6 is essential for CR1 enhancer function through a tandem of sites. A, a prediction of two Pax6-binding sites that resemble motifs 2-1 (site 2) and 2-2 (site 1) in CR1 of the mouse c-Maf locus. B, EMSA confirmation of Pax6 binding to sites 1 and 2. Five point mutations in these Pax6 binding sites were also tested as specific competitors. C, a diagrammatic summary of wild-type CR1 and two mutants, CR1^-Mut and CR1^-Del, in EGFP reporter constructs. D, temporal and spatial analysis of EGFP expression in the presence of two Pax6 mutants (C) in CR1 in transgenic mice. Analysis of additional CR1^-Mut and CR1^-Del transgenic lines is shown in supplemental Fig. S6. LP, lens pit; LV, lens vesicle; 1^oLF, primary lens fibers; RE, retina; RPE, retinal pigmented epithelium. Scale bars = 100 μm (C and D). Blue, DAPI; green, anti-GFP.