Wunen and G protein signaling are not required for germ cell polarization. (A–E) Representative images of embryos at stage 9 stained for Vasa (green, germ cells), Rho1 (red), and actin (phalloidin, blue). Bars, 20 µm. Rho1 concentrates in tail region, and germ cells polarize in wild-type embryo and embryos in which G protein signaling was blocked (A), either by overexpression of Gαo GDP (B) or by removal of Gγ1 from germ cells (C). (D) In the absence of germ cell and somatic wunen (wun M⁻Z⁻), germ cells localize Rho1 and polarize similar to wild-type germ cells. (E) Polarization and Rho1 localization fail in absence of both wunen and tre1. (A′–E′) Rho1 intensity measurement portrayed in fire pseudocolor from black/blue (low) to yellow/white (highest). (C) Gγ1 GLCs (germline clone) require rescue in the somatic tissue (see Materials and methods) to allow for gastrulation. This rescue is not complete, as evident by abnormal posterior midgut morphology seen in many embryos. Germ cells, nonetheless, are still able to polarize (F and G). (F) Quantification of cortical Rho1 concentration graphed as per Fig. 3 E. Error bars represent standard deviation. (G) Polarization quantifications as in Fig. 3 G. For crossing schemes and genotypes, see Table S1.