Binding of Mouse Sperm to β-Galactose Residues on Egg Zona Pellucida and Asialofetuin-Coupled Beads

Abstract

Mouse eggs fixed with paraformaldehyde were incubated with various exoglycosidases and their sperm-binding activities were examined. The number of sperm bound per egg was increased by sialidase treatment and decreased by β-galactosidase treatment. No prominent reduction of sperm-binding was observed after α-galactosidase treatment. Mouse sperm also bound to asialofetuin-coupled agarose beads but not to fetuin-coupled beads. The sperm-binding was abolished when asialofetuin-gel was treated with β-galactosidase specific to the β1→4 linkage orN-Glycanase. Furthermore asialofetuin, but not β-galactosidase-treated asialofetuin, competitively inhibited the binding of sperm to the zona pellucida of live eggs. These results suggest that mouse sperm recognize β-galactose residues of the zona pellucida at the initial stage of the binding.