Fig 3. GSA-1(GF) and knockdown of KIN-2/PKA-R induce Ca²⁺ signaling in an empty spermatheca.

(A) Normalized Ca²⁺ trace of a wild type ovulation before, during, and after transit. Ca²⁺ signal does not rise above basal levels before or after the transit. Time of entry, distal neck closure, and time the sp-ut valve opens and closes are indicated. (B) DIC image of a GSA-1(GF) animal; the spermatheca is indicated by a box. (B’) Ca²⁺ signaling in the unoccupied GSA-1(GF) spermatheca shown in B at an arbitrary timepoint before an ovulation event. Ca²⁺ repeatedly increases, peaks, and then drops to baseline levels. These pulses travel from the distal spermatheca through the bag to the sp-ut valve (S5 Movie). Average pixel intensity trace of the Ca²⁺ signal (C) and kymogram (C’) of the GSA-1(GF) spermatheca are shown. Knockdown of KIN-2 with RNAi results in a similarly pulsing unoccupied spermatheca, as shown by the average pixel intensity trace of the Ca²⁺ signal (D) and kymogram (D’) of a kin-2(RNAi) animal.