Figure 3. Differential expression of class III ubiquitin conjugating enzymes (E2s) in cells of the mouse retina. A-I: Shown here are representative photomicrographs of paraffin-embedded sections labeled with the indicated antibodies. Mouse age in weeks is shown in the bottom right corner of each panel. Abbreviations are as follows: RPE represents retinal pigment epithelium; OS represents outer segments; IS represents inner segments; ONL represents outer nuclear layer; OPL represents outer plexiform layer; INL represents inner nuclear layer; IPL represents inner plexiform layer; GCL represents ganglion cell layer. The magnification bar represents 50 μm, and all photomicrographs were taken at the same magnification. J-R: Enlarged sections are shown of images from (J) highlighting the presence or absence of RPE labeling with the various antibodies. Black arrowheads mark unlabeled RPE nuclei and white arrows indicate nuclei labeled with anti-UbcM2. The magnification bar represents 25 μm.