Fig. 4.

Izumo fails to relocate after the acrosome reaction in the absence of Tssk6. (A) Cauda epididymal sperm of WT and Tssk6-null (KO) mice was obtained as in the Materials and Methods, and total extracts were analyzed by western blot with anti-Izumo antibodies. The lower panel shows the same membrane re-probed with anti-tubulin mAb as a loading control. (B) Epifluorescence localization analysis of Izumo in WT sperm and Tssk6-null sperm (KO) in either intact sperm (No AR) or after Ca²⁺-ionophore-induced acrosome reaction (AR). Note that the PNA staining is lost in acrosome-reacted sperm of both WT and Tssk6-null mice. (C) The percentage of sperm presenting posterior head Izumo staining before (No AR) and after (AR) the acrosome reaction. Results represent the mean ± s.d. of four independent experiments in which 200 sperm were counted per condition (^***P<0.005).