Fig. 1

E(spl)mγ expression reports Notch signalling at the transition zone. (a) Schematic model of the optic lobe transition (TZ) between NE cells into NBs. NE cells divide symmetrically to amplify their pool and transform into PI progenitors, expressing low levels of nuclear Dpn (blue). PI progenitors transform into PII progenitors, characterised by the expression of L’sc (red), and PII progenitors transform into NBs that divides asymmetrically and generate differentiated progeny. Modified from [8]. (b-b”’) Immunostaining of the optic lobe transition zone expressing the Notch reporter (b’) E(spl)mγ-GFP (green) and stained for (b”) Dl (red) and (b”’) Dpn (blue). (c) Schematic model of Notch signalling activation at the optic lobe transition zone, showing two peaks of Notch signalling activation in PI progenitors and in NBs. Scale bars are 20 μm