(full paper is archived in the Miller Library)
Title: Search for a soluble protein factor from sea urchin sperm which would activate eggs when microinjected
Student Author(s): Roberts, Jennifer S
Location: Final Papers Biology 175H
Date: June 1990
Abstract: Two competing models have been proposed to explain the mechanism by which a sperm activates an egg at fertilization. One postulates a receptor while the other relies on fusion as the primary means of signal transduction. This study looked for a soluble activation factor which could act as a diffusible messenger between the fused sperm and egg. S. purpuratus sperm were lysed with 1% Triton to bring all solubilizable proteins and factors into solution. In a second set of experiments, sperm were permeabilized with hypotonic solution and then suspended in an extraction buffer of high salt and pH 8, designed to bring only soluble cytoplasmic elements into solution. Both sets of extracts were microinjected into eggs and activation was monitored by looking for the rise of the fertilization membrane. Under the various conditions used in this study, no soluble fraction from sperm activated the eggs when microinjected.