Figure 4 Expression Patterns of Several Novel Cone Genes Up-Regulated in rd7 In the wild-type images (wt), note the scattered, weakly positive cells at the scleral edge of the outer nuclear layer in a cone distribution. All of the genes show marked up-regulation in the rd7 mutant. Bub1b and Tcta show transcript localization predominantly to the inner segment of the photoreceptors. Retinas are oriented such that the scleral edge is up.