Three distinct roles for notch in Drosophila R7 photoreceptor specification.
Receptor tyrosine kinases (RTKs) and Notch (N) proteins are different types of transmembrane receptors that transduce extracellular signals and control cell fate.Here we examine cell fate specification in the Drosophila retina and ask how N acts together with the RTKs Sevenless (Sev) and the EGF receptor (DER) to specify the R7 photoreceptor.The re