The function of vestigial in Drosophila wing development: how are tissue-specific responses to signalling pathways specified?

The activities of conserved signal transduction pathways are central to the development of Drosophila wings, legs, and eyes. Yet, all these structures have characteristic morphologies, suggesting that additional factors provi de organ-specific information. One excellent candidate for such a function is Vestigial, which activity promotes the formation of wings. The biochemic al function of Vestigial is unknown, however, since no homologies with othe r proteins have been identified. Two recent reports show that Vestigial int eracts with the transcription factor Scalloped,((1,2)) forming an active co mplex that binds to specific DNA sequences and regulates gene expression in cooperation with several signalling pathways.((3)) These results illustrat e how tissue-specific transcription factors cooperate with general signalli ng pathways to regulate gene expression in a tissue-specific manner. (C) 19 99 John Wiley & Sons, Inc.