UV light, radiation, poor nutrition, diabetes, steroid administration and estrogen deficiency have been associated with increased prevalence of cataracts. The goal of this laboratory is to determine expressed gene changes that are involved in cataract formation. Reverse transcriptase- polymerase chain reaction differential display (DD) is a technique that compares the levels of expressed genes between two conditions. This method has been used by our laboratory to analyze expressed gene differences in lenses of UVA-exposed guinea pigs. Guinea pigs exposed to 5 months of UVA light developed early signs of cataract, which included increased nuclear light scattering and a decrease in lens soluble proteins. By DD, two genes associated with neoplasia, EB1 and RIG (Regulated in Glioma), were found to be down regulated in UVA treated lenses. This data suggests that UVA stress in the lens is associated with malignant processes. Differential display has also been used to examine genes involved in protecting mouse lens cells from oxidative damage. Cells were conditioned to survive in high concentrations of hydrogen peroxide. Genes that were up regulated in these cells included glutathione peroxidase, catalase, reticulocalbin, and alphaB- crystallin. The altered expression of these genes is consistent with the function of these proteins in cellular stress response and defense. - cataract, UVA-light, oxidative stress, reverse transcriptase-polymerase chain reaction differential display