Figure 1.

Drosophila glioma models to study cell-cell signaling interactions. Comparisons of overgrowth and glial cell numbers in the dorsal lobe of Drosophila larval brain from mature third instar larvae are shown for the following genotypes: wild-type (A), w; repo-Gal4[4.3] UAS-mCD8:GFP repo-flp5/yw; +/+; FRT82B Tub-Gal80/ UAS Ras^V12 FRT82B scrib² (B, C), UASAkt (D), and yw/UAS Akt; +/UAS Ras^V12; repo-Gal4 UASGFP/+ (E, F). All samples were stained for antibody against the glial-specific marker Repo (red). The samples in (A, B, D, E) show the surface view, and (C, F) show the medial view through the dorsal lobe of the brain. The glioma in (B, C) were generated using the MARCM approach, resulting in positively marked clones (green fluorescent protein expressing) of glial cells that are mutant for the tumor suppressor gene scribble and simultaneously overexpress oncogenic Ras. The glioma in (E, F) were induced by misexpression of oncogenic Ras and Akt in the glial cells using repo-Gal4. Note that both approaches cause overrepresentation of the glial cells specifically and cause overgrowth in the dorsal brain lobes compared with the normal wild-type controls. All images were scanned at identical magnification. Magnification, ×40. Abbreviation: MARCM, mosaic analysis with a repressible cell marker.