SIGNAL-TRANSDUCTION IN THE EARLY DROSOPHILA EMBRYO - WHEN GENETICS MEETS BIOCHEMISTRY

An elegant combination of genetic and biochemical approaches has been used to investigate a variety of signal transduction pathways in devel opmental processes. Here, we describe the 'terminal' signaling system in the Drosophila embryo, which is responsible for pattern formation i n the polar regions of the embryo. This pathway involves a membrane-bo und receptor tyrosine kinase (RTK) that is similar to other Drosophila RTKs, such as sevenless, and the mammalian RTKs, such as the epiderma l growth factor or platelet-derived growth factor receptors.