Figure 7. Progesterone-induced changes in flagellar beat frequency and amplitude of control and CATSPER2^–/– sperm.

(A) Representative time-lapse overlays of 3 beat cycles before (Caged) and after (Uncaged) uncaging progesterone (2 μM) of a pivoting head-tethered capacitated control sperm from a donor. (B) Representative change of angle θ over time (solid line, upper panels) with the corresponding slope (dotted line) and fitted sine wave of the oscillation (lower panels) of control (black, left panel) and CATSPER2^–/– sperm (gold, right panel) from patient C1 before and after uncaging progesterone. The corresponding frequency and amplitude of the flagellar beat were derived from the fitted sine wave, and the rotation velocity, Ω (°·s^–1) were derived by the slope of the change of θ over time. The mean values (± SD) for 9 sperm from donors and patient C1 are provided in Supplemental Figure 8.