Part of the Notch signaling pathway. Expressed at the time when separation of neural and epidermal precursors cells occurs. Detected in the neuro-ectoderm of stage 9 embryos. At stage 10/11, accumulates at high levels in the presumptive mesoderm, however, it disappears quickly with the onset of germ band retraction. In eye disk, expression occurs close to, as well as posterior to the morphogenetic furrow. In the wing disk, found in the proneural clusters areas, the dorso-ventral boundary and vein/intervein regions.