Figure 7

Immunofluorescent localization of RSPO1 protein in E8.5 and E12.5 embryonic chicken gonads (ten micron transverse sections). A) E8.5 left ovary. Double-staining for aromatase (red; medulla) and RSPO1 (green; cortex). B) E12. 5 left ovary. Double-staining for aromatase (red; medulla) and RSPO1 (green; cortex). C) E8.5 right female gonad, showing aromatase expression in the medulla, but no RSPO1 expression due to the reduced cortex. D) E8.5 testis, showing no expression of aromatase or RSPO1. E) High magnification view of the left ovarian cortex, showing RSPO1 expression (green) in the extracellular matrix and at the cell surface (e.g., arrows) and in cell cytoplasm (e.g., arrowhead). F) Loss of RSPO1 protein (green) in an E12.5 female left gonad treated with aromatase inhibitor at E3.5. Aromatase protein is weakly expressed (red), due to fadrozole inhibition, and the cortex is absent.