Immunostaining analysis of sperm heads and tails in WT and KO mice. Sperm tails were observed by immunostaining for α-tubulin antibody (red), and counterstaining with the nuclear dye Hoechst 33342 (blue). Sperm were also observed by differential interference contrast (DIC) microscopy. Scale bars = 20 μm (upper) and 5 μm (lower). 