The Importance of Actin in the Acrosome Reaction
The effects of inhibitors of actin polymerization on the mouse fertilization process were investigated. Fertilization is composed of the following steps: sperm capacitation, sperm-zona pellucida binding, the acrosome reaction, penetration of the zona pellucida, sperm-oocyte membrane binding, sperm-egg fusion, egg activation, and the cortical reaction. In this research, we focused on two of these stages: sperm capacitation and the acrosome reaction. Fertilization experiments were conducted to study the function of protein components found in sperm and many cells, F-actin and G-actin. It has been proven that inhibition of actin polymerization by pharmacological agents will completely prevent motility, endocytosis, and phagocytosis. We collected mouse epididymal sperm by carefully puncturing the cauda and allowing sperm to swim out. We capacitated them and added ionophore to induce the acrosome in the presence or absence of actin polymerization inhibitors. Then we looked at the sperm by using Coomassic Blue G-250 stain to stain microscope slides When we looked at the sperm on the slides we saw a significant different in the number of acrosomes that did not reacted and the ones that did. This sperm had different concentrations of an actin inhibitor called Cytochalasin D and at the higher the concentration the higher the number of acrosomes that were intact. Our results suggest that actin polymerization represents an important regulatory pathway in sperm capacitation and the fertilization process.
University of Puerto Rico at Bayamón
Dr. David J. Miller
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