FIG. 5.

Ultrastructure of epididymal and testicular sperm from Spag6^−/− mice. (A) Immunoelectron microscopy localization of Spag6 in wild-type epididymal sperm using colloidal gold-labeled antibody. Spag6 is localized in the central apparatus. Control sections processed in the absence of primary antibody showed no specific localization (not shown). Inset, transverse section through a wild-type epididymal sperm viewed by transmission electron microscopy. (B) Ultrastructure of Spag6^−/− testicular sperm revealing normal flagellar architecture (C) Transverse section from a Spag6^−/− epididymal sperm lacking a central apparatus (arrowhead). (D) Transverse sections through Spag6^−/− epididymal sperm showing intact central apparatus microtubules but supernumerary (a) and disorganized outer dense fibers (b).