Participation of the nonreducing terminal beta-galactosyl residues of the neutral N-linked carbohydrate chains of porcine zona pellucida glycoproteins in sperm-egg binding.
The zona pellucida (ZP) surrounding the mammalian oocyte is composed of three glycoprotein components (ZPA, ZPB, and ZPC). Mammalian sperm bind to carbohydrate chains of a ZP glycoprotein in the initial phase of fertilization. Sperm-ligand carbohydrate chains have been characterized in mouse, cow, and pig. In pigs, triantennary/tetraantennary neutral complex-type chains from ZPB/ZPC mixture possess stronger sperm-binding activity than those of biantennary chains (Kudo et al., 1998: Eur J Biochem 252:492-499). Most of these oligosaccharides have beta-galactosyl residues at the nonreducing ends. This study used two in vitro competition assays to investigate the participation of the nonreducing terminal beta-galactosyl residues of the ligand active chains in porcine sperm binding. The removal of the nonreducing terminal beta-galactosyl residues from either the ligand active carbohydrate chains or endo-beta-galactosidase-digested glycoproteins significantly reduced their inhibition of sperm-egg binding, indicating that the beta-galactosyl residues at the nonreducing ends are involved in porcine sperm-egg binding. A correlation between the sperm-binding activity and in vitro fertilization rate is also presented.
Yonezawa
N
N
Graduate School of Science and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-shi, Chiba 163-8522, Japan.
Amari
S
S
Takahashi
K
K
Ikeda
K
K
Imai
F L
FL
Kanai
S
S
Kikuchi
K
K
Nakano
M
M
D000818:Animals; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D002417:Cattle; D004527:Egg Proteins / Q000737:chemistry* / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D005690:Galactose / Q000737:chemistry*; D006026:Glycoside Hydrolases / Q000737:chemistry; D008024:Ligands; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000502:physiology; D051379:Mice; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013552:Swine / Q000502:physiology; D015044:Zona Pellucida / Q000737:chemistry / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
D002241:Carbohydrates; D004527:Egg Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D006026:Glycoside Hydrolases; C026093:keratan-sulfate endo-1,4-beta-galactosidase; D005690:Galactose