MODIFICATIONS OF CARBOHYDRATE RESIDUES AND ZP2 AND ZP3 GLYCOPROTEINS IN THE MOUSE ZONA-PELLUCIDA AFTER FERTILIZATION

Oligosaccharide side chains of zona pellucida (ZP) glycoproteins play a key role in the sperm-egg interaction phenomena during fertilization . In the present study, modifications of the ZP glycoproteins during t he fertilization process in the mouse were studied by the lectin-gold technique and immunocytochemistry in conjunction with quantitative ana lysis. Binding of PNA, RCA I, DSA, LFA, MAA, AAA, and anti-ZP2 and ant i-ZP3 antibodies was observed throughout the ZP of both unfertilized a nd fertilized eggs. However, HPA and BSAIB(4) labeling was found only in the inner region of the ZP. After neuraminidase treatment (Neu), HP A showed an affinity for the entire ZP. Labeling by LFA, WGA, MAA, PNA , BSAIB(4), and AAA decreased in the ZP of fertilized eggs; however, t here was an increase in the binding of RCA I. HPA and Neu-HPA increase d only in the inner region of the ZP. Immunoreactivity to antibodies a gainst ZP2 and ZP3 also decreased after fertilization. The present res ults demonstrate that 1) terminal carbohydrate residues contained in t he ZP glycoproteins are modified after fertilization and 2) inner and outer regions of the ZP contain different oligosaccharide side chains.