NUCLEAR FACTORS IN SEVENLESS SIGNALING

Recent studies in both vertebrates and invertebrates support all 'hour glass' model for signal transduction from receptor tyrosine kilnases: Ras channels signals front diverse receptor tyrosine kinases into a co mmon cytoplasmic kinase cascade, the targets of which are an even more diverse collection of nuclear proteins. What are these nuclear factor s, and bow do they interact to direct specific cellular responses to a generic signal? The past year has brought considerable progress in ou r quest to answer these questions in one model genetic system, the Dro sophila eye.