Identification of Drosophila wing imaginal disc proteins by two-dimensional gel analysis and microsequencing.

We have combined high-resolution two-dimensional (2D) gel electrophoresis with microsequencing techniques in order to identify proteins in the 2D gel database of wing imaginal discs of Drosophila melanogaster. First, a high-resolution 2D gel separation pattern of the [35S]methionine-labeled polypeptides from CME W2 cells, a stable cell line derived from wing imaginal discs, is presented and compared with the standard pattern of polypeptides of wing imaginal discs. These studies reveal significant qualitative and quantitative alterations in polypeptide expression between both samples. Second, we carried 2D PAGE to the preparative level using the CME W2 cell line mixed with radioactively labeled wing imaginal discs in order to identify some common polypeptides and subsequently characterized them by microsequencing techniques. Using these methods we obtained partial amino acid sequences of several Drosophila proteins of the 2D gel protein database. As an illustration we present 12 of them: 8 corresponding to proteins already known in Drosophila and the 4 showing homologies with proteins of other organisms.