Conserved domains in Tre1 GPCR are required for germ cell migration. (A) Schematic drawing of Tre1 protein and the location of the conserved domains. Amino acid alterations are listed to the right in red. (B) Scatterplots showing number of germ cells in the gonad in each genotype as a percentage of the total. Error bars represent standard deviation; +/− indicates transheterozygotes. At least 20 embryos were analyzed per genotype. ***, P < 0.001. There is no significant difference between tre1-null and tre1 NRY⁻NPIIY⁻. (C–G) Representative images of embryos at stage 14 stained for Vasa (green, germ cells), Eya (somatic gonad, red; gray in C′–G′), and actin (phalloidin, blue). All embryos shown lack maternal and zygotic contribution of endogenous tre1 gene, (tre1⁻) and inherited maternally provided Tre1 wild ype (tre1⁺; C) or mutated forms of the receptor expressed from the respective tre1 transgene under nanos promoter, nanos 5′ and 3′ UTRs (D–G). Bars, 50 µm. The somatic gonad is outlined in yellow hashes. For crossing schemes and genotypes, see Table S1.