Roles Played by Enhancer of Split Transcription Factors in R7 Photoreceptor Specification.

When a cell receives multiple developmental signals simultaneously, the intracellular transduction pathways triggered by those signals are coincidentally active. How then, do the cells decode the information contained within those multiple active pathways to derive a precise developmental directive? The specification of the Drosophila R7 photoreceptor is classic model system for investigating such questions. The R7 fate is specified by the combined actions of the of the Notch (N) and receptor tyrosine kinase (RTK) signaling pathways.