Fig. 2. Loss of Ago1 disrupts GSC maintenance in Drosophila. Ovaries collected from {hs-Ago1; Ago1/Ago1} flies undergoing different treatments were stained with anti-Vasa (green) and anti-Hts (red) antibodies. (A) Example of a germarium from an {hs-Ago1; Ago1^k08121/Ago1^k0812} animal 3 days after withdrawal of heat shock, in which two GSCs were maintained well. (B-D) In Ago1 mutants germ cell development was severely defective. There were no GSCs maintained at day 15 after withdrawal of heat shock. Allele combinations of (B) Ago1^k08121/Ago1^k08121,(C) Ago1^k08121/Ago1¹⁴ and (D) Ago1^k08121/Ago1^EMS are shown. (E) Example of the germarium of a fly undergoing constitutive heat shock, in which two GSCs were maintained well. (F) AGO1 is expressed almost equally in ovary, embryo and adult. In Ago1^k08121/Ago1¹⁴ mutant flies rescued by the transgene P{hs-Ago1}, the AGO1 protein was undetectable at day 15 after withdrawal of heat-shock treatment. Scale bar: 10 µm.