Figure 8

Specific labeling of DM lineages by Dll-Gal4. Confocal images of third instar larval nervous system expressing mCD8::GFP (green) and H2B::RFP (red in A, B) under the control of Dll-GAL4 and immunostained with anti phospho-histone 3 (PH3, blue) and anti-prospero (PROS, red in C). Panels in the left column show merged views of individual channels presented in grey scale in the middle and right columns for clarity. Green dotted lines indicate the contours of the GFP-labeled domains. (A-A") Dorsal view of a larval central nervous system at low magnification reveals restricted expression of the reporter genes in the medial part of the brain hemispheres (B) in the optic lobes (OL) and a few cells in the ventral ganglia (VG). (B-B") Higher magnification of the dorsomedial area in the left brain hemisphere. Shown are three DM neuroblasts (asterisks) and their closely associated progeny cells. Scattered cells undergoing mitosis are observed throughout the cell clusters (arrows). (C-C") Three DM lineages marked by Dll-GAL4 expression lack expression of Prospero in the neuroblasts and their surrounding daughter IP cells (C; asterisks and white dots, respectively). IP cells undergoing mitosis (arrows) are marked by PH3 staining (C"; arrows). They show a crescent localization of prospero (C'; arrows) in contrast to the nuclear localization of the protein in most post-mitotic cells visible in the field.