| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1984: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
In the present study, we analyzed the sperm receptor activity of the zona glycoproteins from mouse ovarian oocytes, and oligosaccharides in individual glycoproteins. For the determination of the glycoprotein that has the sperm binding activity, we used a in vitro binding assay. Capacitated sperm were tested for the binding to the glycoprotein immobilized on latex beads. The results indicated that ZP-3 glycoprotein had the highest capacity to bind sperm. However, no positive results were obtained in an attempt to determine the sperm components that had the binding activity to ZP-3.
Assuming that the ZP-3 glycoprotein might have the unique carbohydrates reflecting its functional difference from the rest of zona glycoproteins, gel chromatographic comparison of the oligosaccharides was made using isotopically labeled glycoproteins. All of the zona glycoproteins contained both O- and N-linked oligosaccharides, although carbohydrate content and ratio of the amount of O- and N-linked oligosaccharides siffered among the glycoproteins. N-linked carbohydrates had negative charge not released by sialidase, and contained N-acetylgalactosamine usally not found in N-linked oligosaccharides. All three glycoproteins showed the similar patterns on gel chromatography of both O- and N-linked oligosaccharides, and no characteristic difference of oligosaccharides has been detected among the glycoproteins. However, ZP-3 oligosaccharides from two-cell embryos gave altered patterns from unfertilized eggs, probably reflecting the functional modification of the zona pellucida in two-cell embryos. Future studies on these oligosaccharides that undergo the structural changes in fertilization could result in the elucidation of the mechanism of sperm-egg interaction.
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