Colocalization of Wt1 and EPO in the adult murine testis. Double-immunofluorescence labeling for Wt1 (red) and EPO (green) in sections of the adult testis. (B-C) Staining of Wt1. (A) Negative control. Wt1 is present only in the nuclei of Sertoli cells. (E-F) Staining of EPO. (D) Negative control. EPO is detected in various cell types of the testis, but colocalization with Wt1 is restricted to Sertoli cells (yellow fluorescence, I). Counter-staining with DAPI is also shown in slides used for negative controls. SeC indicates Sertoli cell; LeyC, Leydig cell; SpeG, spermatogonia; SP, sperm.