Fig. 2.

Detecting Notch activity in wing imaginal discs. Expression of a Notch responsive reporter (A, NRE-GFP; detected using anti-GFP) and two Notch regulated genes (B, cut; C, wg; detected using indicated antibodies) in the third instar wing imaginal disc. All exhibit Notch-dependent expression at the d/v boundary (stripe indicated by white arrow) but otherwise their expression patterns differ. These differences highlight the strengths and the pitfalls associated with using different gene targets to read-out Notch activity. NRE-GFP reveals that there are low levels of Notch activity more broadly in the wing pouch (A), which are associated with wing-vein development. Neither cut nor wg report these other sites of Notch activity. Conversely, wg has an additional pattern of Notch-independent expression (C, rings surrounding the wing-pouch).