Fig. 2.

Notch signalling regulates PI progenitor fate and prevents PII progenitor conversion into neuroblasts. (a-Aa”) Staining of clone misexpressing the N^ICD in the optic lobe transition zone. Clone was marked by β-gal expression (blue) and marked by dotted lines; E(spl)mγ expression in green, and Dpn in red. (b-b”) Wild-type brain transition zone stained for E(spl)mγ in green, Dpn in red and Notch receptor in blue (b) or grey (b”). Arrows indicate the end of Notch receptor and Notch signalling activation (c-d”) Staining of clones misexpressing a full length Notch receptor (N^FL) for (c - d”) E(spl)mγ in green, Dpn in red (c, c”) and L’sc in red (d, d”). Arrows indicate E(spl)mγ activation after PI progenitor formation and (d-d”) a delay in PII progenitor transformation into NBs. Arrowheads show cells in the clone that do not activate Notch signalling (c-c”). Scale bars are 20 μm