Figure 2.

Putative ecdysone-responsive genes are required for GSC and FSC maintenance. (A) The FLP/FRT technique was used to generate genetic mosaics. Mitotic recombination is mediated by heat-shock-induced expression of flippase (hsFLP). Homozygous mutant (mut) cells are identified by the absence of a GFP marker, which is linked to the wildtype allele. (B–E) Representative control mosaic (B, D) or ecdysone-responsive mutant mosaic (C, E) germaria labeled with anti-GFP (green), anti-Hts (red; fusomes and follicle cell membranes), and anti-LamC (red; nuclear envelope of cap cells). Dotted lines and asterisks demarcate wildtype GFP-negative GSCs (B) or FSCs (D); solid lines demarcate GFP-positive GSCs (B–C) or FSCs (D–E). In control mosaic germaria, where all cells are genetically wildtype, GFP-negative daughter germ cells (arrows, B) and follicle cells (arrows, D) co-exist with GFP-negative GSCs and FSCs. In Hrb27C mutant mosaics (C), GFP-negative daughter germ cells are frequently observed in the absence of their GFP-negative mother GSC. Similarly, pnt mutant mosaics (E) are frequently observed with GFP-negative follicle cells, but without a GFP-negative mother FSC. Scale bar, 10 µm.