The light-absorbing pigments necessary for vision are on special membranes within photoreceptor cells in the eye. The maintenance of these membranes in the living eye occurs through processes of membrane shedding and renewal. This project will unravel this important visual mechanism by exploiting mutants of the famous fruit fly, Drosophila, that have particular visual deficits to correlate with observed ultrastructure in the eye. Electron microscopy and freeze-fracture techniques will be used to examine the stages of membrane turnover within the photoreceptor cells. Both abnormal diets and mutant flies with unusual periodicity of recycling will be used as probes to examine correlations of structure with visual function. This study will provide important new data on invertebrate photo- receptors, to compare with those of vertebrate eyes, and provides a novel genetic approach to an issue that is of crucial importance to vision in general.
