Aag-dependent alkylation-induced retinal degeneration in mature retina. Animals of genotypes as shown were untreated (Left) or treated at 6–8 weeks of age with either 75 mg/kg MMS (Center) or 60 mg/kg MNU (Right). At least 3 animals were treated per genotype, per drug. GL, ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; OS, outer segments. Representative photomicrographs are shown at a magnification of 400×. (Bars: 100 μm.)