Fig. 7. FGFR2 colocalizes with SRY^EGFP and SOX9 in Sertoli cell precursors. In XY gonads at 11.5 dpc, nuclear FGFR2 (green) was detected in cells expressing EGFP under the control of the Sry promoter (red, found within the nucleus and cytoplasm). Cells where FGFR2 and EGFP colocalize are indicated by arrows (A). The EGFP reporter is also expressed in XX gonads. FGFR2 is detected in XX gonads at the coelomic surface, but is not found within the nucleus (B). Nuclear FGFR2 (green) was found in every nucleus labeled with SOX9 (red; C), while neither nuclear FGFR2 nor SOX9 was detected in the XX gonad (D). Blood cell autofluorescence was observed in both blue and red channels, and is pink. Red and green channels are separated in E-G to show the overlap of FGFR2 (green) and SOX9 (red). Germ cells and vasculature are labeled with PECAM and are blue. E-G are 200x magnification of the gonad shown in C. Scale bar: 25 µm.