Figure 6

Immunofluorescent localization of Rspo1 protein in E14.5 embryonic mouse gonads. A) Rspo1 immunofluorescence in a female gonad. Expression is detectable throughout the gonad, in cell cytoplasm and at the cell surface (e.g.; arrow). Transverse section. B) Background staining in male gonad. Transverse section. C) Double staining for Rspo1 (green) and Wt1 (red) in a female gonad. Most cells that are Rspo1⁺ and also Wt1⁺ (e.g., arrow). Some cells stain for Rspo1 but not Wt1 (e.g;. arrowhead). Transverse section. D) Wt1 (red) but not Rspo1 expression in the male gonad (arrows show Wt1 protein in the seminiferous cords). E) Double-staining for Rspo1 (green) and the meiotic germ cell marker, Scp3 (red), showing Rspo1 protein at the germ cell surface (arrow), and also in Scp3^- somatic cells (arrowhead). Transverse section. F) Double-staining for Rspo1 (green) and Scp3 (red) shows no expression in the male.