Genetically labeled neurons in third instar larval brains and primary cell cultures. Fixed (A-F, H-J”) and live samples (G-G”). Anti-Elav (blue) labels nuclei of neurons in culture (B, D, F), anti-GFP (green) labels genetically identifiable cells and DAPI shows DNA. (A, B) Expression of UAS-CD8::GFP driven by pdf-Gal4 (pdf >CD8::GFP) reveals the eight LNs in the third instar brain (A) and in primary cell culture (B). (C, D) GH146 > CD8::GFP shows GFP-expression (green) in projection neurons of the antennal lobe and the developing optic ganglia (C) and in primary cell culture (D) (arrows indicate outgrowing neurites) (E, F) MB247 > CD8::GFP labels Kenyon cells in the mushroom bodies of the larval brain (E) and in cultured cells (F). (G, G’, G”) DIC images overlaid with confocal images shows living GFP-expressing cultured neurons and their neurite extensions (G’ is an overview, G’ and G” are higher magnifications). (H) Shown are secondary neurons in a mCD8::GFP labeled MARCM clone. Brain tissue is stained with anti-Dlg (red) (I) Dissociated secondary neurons reveal small extensions in culture. J, J’, J’’) Cells plated on Concanavalin A coated slides show neuronal extensions. Neurites are still visible after 5 h but have largely disappeared at 25 h after plating. Cell morphology is given by anti-Nrg staining (green).