Sea urchin egg activation at fertilization is progressive, beginning at the point of sperm entry and moving across the egg with a velocity of 5 microns/s. This activation wave (Kacser, H., 1955, J. Exp. Biol., 32:451-467) has been suggested to be the result of a progressive release of calcium from a store within the egg cytoplasm (Jaffe, L. F., 1983, Dev. Biol., 99:265-276). The progressive release of calcium may be due to the production of inositol trisphosphate (InsP3), a second messenger. We show here that a wave of calcium release crosses the Lytechinus pictus egg; the peak of the wave travels with a velocity of 5 microns/s; microinjection of InsP3 causes the release of calcium within the egg; calcium release (as judged by fertilization envelope elevation) is abolished by prior injection of the calcium chelator EGTA; neomycin, an inhibitor of InsP3 production, does not prevent the release of calcium in response to InsP3 but does abolish the wave of calcium release; the egg cytoplasm rapidly buffers microinjected calcium; the calcium concentration required to cause fertilization membrane elevation when microinjected is very similar to that required to stimulate the production of InsP3 in vitro; and the progressive fertilization membrane elevation seen after microinjection of calcium buffers appears to be due to diffusion of the buffer across the egg cytoplasm rather than to the induction of the activation wave. We conclude that InsP3 diffuses through the egg cytoplasm much more readily than calcium ions and that calcium-stimulated production of InsP3 and InsP3-induced calcium release from an internal store can account for the progressive release of calcium at fertilization.
Skip Nav Destination
Article navigation
1 December 1986
Article|
December 01 1986
The part played by inositol trisphosphate and calcium in the propagation of the fertilization wave in sea urchin eggs.
K Swann
M Whitaker
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1986) 103 (6): 2333–2342.
Citation
K Swann, M Whitaker; The part played by inositol trisphosphate and calcium in the propagation of the fertilization wave in sea urchin eggs.. J Cell Biol 1 December 1986; 103 (6): 2333–2342. doi: https://doi.org/10.1083/jcb.103.6.2333
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionSuggested Content
Email alerts
Advertisement
Advertisement