Boi sequesters Hh on the surface of apical cells. (A and B) Wild-type (WT; A) or boi^e mutant (B) germaria showing Boi (green) and Hh (red) expression in apical cells (brackets). Redistributed Hh is indicated (B, arrows). (C) Rescue of Hh (red) and Boi (green) localization by wild-type boi expression in apical cells (bracket, boi^e; UAS-boi/+; babGal4/+). Nuclei are labeled (Draq5, blue). (D) Boi^ΔFN1 (green) lacks the Hh-binding domain and fails to rescue Hh (red) localization (brackets, boi^e; UAS-boi^ΔFN1/+; babGal4/+). Hh accumulates near FSCs (arrows) as in boi mutants. (E) Ihog expression (boi^e; ihog^EP/+; babGal4/+) rescues Hh localization (red). Germ cells are labeled (anti-Vasa, blue). (F) Mean cell number in the first stalk for each genotype is shown. *, significant differences relative to control (babGal4/+, P < 0.00002). **, significant differences relative to boi^e; babGal4/+ (P < 0.00002). (G) Mean numbers of dividing FSCs (PH3+) per germarium are shown. *, significant differences relative to control (babGal4/+, P < 0.001). **, significant differences relative to boi^e; babGal4/+, (P < 0.02). Error bars represent SEM.