Fig. 2. Jak/Stat signalling is required in the Drosophila ovary for GSC maintenance. (A,B) Wild-type (A) and hop²⁷/hop²⁵ upd^YM55 (B) germaria stained with anti-Hts to visualise the clear reduction in the number of GSCs and developing cysts in the mutant condition. (C,D) nanos- Gal4/UASt-Src:GFP (C) and hop²⁷/hop²⁵; nanos-Gal4/UASt-Src:GFP (D) germaria dissected 10 days after eclosion (AE). They were double stained with anti-Hts (red) and anti-GFP (green) to visualise spectrosomes and to outline the germline cells, respectively. The spectrosome in C displays the typical `exclamation mark' shape (de Cuevas and Spradling, 1998); the spectrosome in D has lost its apical anchoring while still maintaining its connection with the cystoblast spectrosome and was therefore classified as an anchorless GSC spectrosome. The small `scar' of spectrosomal material left on the apical side, adjacent to the CpCs, suggests that the GSC spectrosome has severed its apical connection prior to accumulating basally. (E) Bar chart representing the mean number of GSCs (±s.d.) per germarium in hop²⁷/FM7 (control), hop²⁷/hop²⁵ and hop²⁷/hop²⁵ upd^YM55 germaria. Ovaries were dissected 2, 10 and 25 days AE. Black triangles indicate a statistically significant difference between the given experimental condition and its control (Student's t-test, P<0.01). (F) Bar chart showing the percentage of anchorless GSC figures in hop²⁷/FM7 (control), hop²⁷/hop²⁵ and hop²⁷/hop²⁵ upd^YM55 germaria dissected 2, 10 and 25 days AE. The number of germaria analysed for each experiment (n) shown in E,F is indicated in E. Asterisks, GSCs; CB, cystoblast. The white dashed lines delineate GSC-CB pairs. Scale bars: 10 µm.