Insemination or phosphatidic acid induces an outwardly spiraling disk of elevated Ca²⁺ to produce the Ca²⁺ wave during Xenopus laevis fertilization.

ABSTRACT: During Xenopus fertilization, the initial intracellular calcium ((Ca²⁺)_i) release at the sperm-egg binding site (hot spot) has not been described without the use of inhibitors, nor related to underlying ER structure. Without inhibitors, we now report that sperm induce an initial hot spot after sperm addition to Xenopus eggs that was ~25 µm. This area is consistent with the size of ER patches and clusters of IP3 receptors that have enhanced activity. Furthermore, we find a new mechanism for the fertilization (Ca²⁺)_i wave; instead of outward diffusion of inositol 1,4,5-trisphosphate (IP₃), we find that the wave was generated by an outward, clockwise rotation of a ~63 µm disk of elevated (Ca²⁺)_i moving very rapidly a

SUBMITTER: Fees CP 

PROVIDER: S-EPMC6424626 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature