FIG. 3.
CATSPER channels are required for the ZP-induced [Ca2+]i rise in the sperm head. A) Recording from a wild-type sperm. Note that there were two phases of [Ca2+]i changes in this cell. B and C) Recordings from Catsper1-null sperm. The delayed response was present in the cell in C. Ca2+ ionophore ionomycin (10 μM) was applied as a control stimulus. D) A representative recording from a transgenic sperm expressing a GFP-CATSPER1 fusion protein in the Catsper1-null background. E) Percentage of cells responsive to ZP application within 2 min in wild-type (WT) (n = 24 imaging runs, 14 mice, 160 cells), Catsper1-null (Mut) (n = 11 imaging runs, five mice, 78 cells), and Catsper1-mutant mice rescued with the GFP-Catsper1 transgene (Tg) (n = 8 imaging runs, three mice, 86 cells). Cells from two Catsper1-null and the three Tg mice were imaged with Fura-2 AM, and the others were imaged with Fluo-4 AM. ΔF:F0 shown as ΔF/F0 (%) and F340:F380 shown as F340/F380.