Two-Dimensional Gel Analysis of Polypeptides in Drosophila Compound Eyes

Abstract

Several years ago, we undertook an analysis of Drosophila eye proteins in the hope of identifying eye-specific proteins that might be involved in molecular mechanisms of visual excitation. We chose Drosophila melanogaster as an experimental organism because of its well-known genetics and the availability of a large number of mutants defective in visual function (Pak 1975; Pak 1979; Hall 1982). The approach we took was to apply two-dimensional Polyacrylamide gel electrophoresis (2-D gel) to the analysis of proteins in the compound eye of both wild-type and mutant flies. Fujitaand Hotta (Fujita and Hotta 1979; Hotta 1979) first applied this technique to Drosophila eyes and showed that three polypeptides observed in 2-D gel originate from the compound eye. In addition to these three, we found at least three other polypeptides that are specific to the photoreceptor layer (Matsumoto et al. 1982). Moreover, the three polypeptides we identified (designated as 80 K, 49 K, and 39 K) were found to alter their isoelectric points in response to a light stimulus in vivo (Matsumoto et al. 1982).