Fig. 1. Ectopic expression of Ago1 increases the number of GSCs. (A) A schematic diagram of a Drosophila germarium with different cell types labeled by different colors: GSCs blue, CBs and cysts green, terminal filaments (TFs) gray, cap cells (CPCs) deep green, inner germarium sheath cells (IGSs) pink, follicle cells (FCs) and fusomes red. (B) Ovaries collected from wild-type (w¹¹¹⁸), P{hs-Ago1} and piwiEP; P{hs-gal4} flies before heat-shock and after 6 days and 10 days heat-shock treatment, as indicated, were stained with anti-Vasa (green) and anti-Hts (red) antibodies. Vasa-positive germ cells carrying spectrosomes were undifferentiated germ cells (GSCs/Cb and GSC-like cells). (C) A germarium from 10-day heat shock was morphologically tumorous; many GSC-like cells carrying spectrosomes (both panels) and differentiated germ cells carrying branched fusomes (right panel) were observed. Scale bar: 10 µm.