Movie S1.

Live imaging of sperm motility. Cauda epididymal sperm from wild-type (WT) and ACRBP-deficient (KO) mice were capacitated by incubation in TYH medium for 2 h and subjected to live-imaging analysis. KO sperm were morphologically divided into three groups (type 1/type 2, type 3, and type 4) and observed by video recording at 200 frames per second under a phase-contrast microscope equipped with a high-speed camera. Note that the type 1 KO sperm were indistinguishable from the type 2 sperm based on morphology, without staining of the acrosome and nucleus. Playback speed is 0.125-fold. (Magnification: 32×.)