Figure 6. egg knockdown in ECs causes EC gradual loss and increases BMP signaling in differentiated germ cells.

(A–E) RNAi-mediated knockdown of egg causes accumulation of single germ cells containing a spectrosome (arrowhead, A and C) in addition to endogenous GSCs (arrows, A and C), while removal of a copy dpp gene using dpp^hr4 or dpp^hr56 mutation can suppress the germ differentiation defect and thus increase normal germaria with two or three GSCs (arrows) and differentiated germ cells (B and D). The quantitative results are summarized in E. (F–H) RNAi-mediated dpp knockdown in ECs fails to suppress the germ cell differentiation defect caused by egg knockdown in ECs. Double knockdown germaria still accumulate excess spectrosome-containing single germ cells (arrowheads, F and G) in addition to endogenous GSCs (arrows, G). The quantitative results are summarized in H. (I–K) dally knockdown in ECs suppresses the germ cell differentiation defect evidenced by a decrease in spectrosome-containing single germ cells (arrowheads in I; endogenous GSCs indicated by arrows in J). K shows quantitative results. (L, M) egg knockdown in ECs (arrowheads, M) does not affect pERK expression in in comparison with control ECs (arrowheads, L). Ovals in L and M indicate cap cells. Scale bars: 10 µm.