IDENTIFICATION OF GENES THAT INTERACT WITH THE SINA GENE IN DROSOPHILA EYE DEVELOPMENT

The sina gene encodes a nuclear protein that is required for the corre ct development of R7 photoreceptor cells in the Drosophila eye. We con ducted a genetic screen for mutations that reduce the activity of sina and found mutations that define nine genes whose products may be requ ired for normal sina activity. Three of these genes also appear to be essential for signaling by the Sevenless-Ras pathway in R7 cells, of w hich one gene corresponds to the rolled locus (rl). The rl gene is kno wn to encode a mitogen-activated protein kinase necessary for signalin g by Ras. These results suggest that the products of these three genes may participate in a signaling pathway involving both Ras and Sina, p ossibly by functionally linking these two proteins.