Figure 5.

ω-Agatoxin TK inhibits membrane retrieval but not cortical granule exocytosis. Sea urchin eggs were incubated in ASW containing 100 μM TMR-Dex, either with (C and D) or without (A and B) 50 nM ω-agatoxin TK. Eggs were fertilized by the addition of sperm. After 15 minutes, the eggs were washed in ASW to remove extracellular TMR-Dex. Eggs were imaged on a Zeiss Axiophot microscope by using differential interference contrast optics (A and C) to visualize the elevation of the fertilization envelope and with a rhodamine filter set to visualize fluorescent inclusions (B and D). (Bar = 30 μm.)