Fig. 4.

Germ line-specific expression of RNA binding-defective yps and Ybx1 mutants severely compromises GSC development. Ovals indicate cap cells, whereas arrows and arrowheads point to spectrosomes in GSCs and CBs, respectively. (A–F′) Germ line-specific expression of yps^W68A, Ybx1^w65A, and Ybx1^F74A, but not of Ybx1^H87A, significantly decreases GSCs and increases CBs compared with overexpression of wild-type yps and Ybx1. F and F′ show results. Some yps and Ybx1 mutant-expressing germaria contain no GSCs (C and E) or one GSC (D), whereas other germaria accumulate many CBs (C′ and D). (G–K) Germ line-specific expression of yps or Ybx1 mutants except Ybx1^H87A decreases EdU⁺ GSCs compared with controls. In G, the arrow indicates EdU⁺ GSC. K shows quantification results.