Analysis of protein-linked glycosylation in a sperm-somatic cell adhesion system.
Murine sperm initiate fertilization by binding to the specialized extracellular matrix of their complementary eggs, known as the zona pellucida. On the basis of data reported in this study, mouse sperm also bind to rabbit erythrocytes with higher affinity than they do to murine eggs. This unusual interaction between a germ cell and a somatic cell ("sperm-somatic cell adhesion system") is also carbohydrate dependent based on its sensitivity to mild periodate oxidation. To determine what types of carbohydrate sequences could be involved in this interaction, the protein-linked oligosaccharides of rabbit erythrocytes were sequenced using novel matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry methods that enabled the analysis of individual components up to m/z 9000. The N-glycans are primarily complex biantennary and triantennary types terminated with Galalpha1-3Gal sequences. The majority of these oligosaccharides also possess one antenna consisting of a highly branched polylactosamine-type sequence that is also associated with many glycosphingolipids that coat rabbit erythrocytes. These erythrocytes also express Core 1 and Core 2 O-glycans terminated primarily with Galalpha1-3Gal sequences and to a lesser extent sialic acid. These results confirm that rabbit erythrocytes and mouse eggs present very different types of carbohydrate sequences on their surfaces. However, oligosaccharides terminated with beta1-6-linked N-acetyllactosamine or its alpha1-3 galactosylated analog are expressed on both the mouse zona pellucida and this somatic cell type. The far more abundant presentation of such sequences on rabbit erythrocytes compared with murine eggs could explain why mouse sperm display such exceptional affinity for this somatic cell type.
Sutton-Smith
Mark
M
Division of Molecular Biosciences, Imperial College London, London, SW7 2AZ, UK.
Wong
Nyet Kui
NK
Khoo
Kay-Hooi
KH
Wu
Sz-Wei
SW
Yu
Shin-Yi
SY
Patankar
Manish S
MS
Easton
Richard
R
Lattanzio
Frank A
FA
Morris
Howard R
HR
Dell
Anne
A
Clark
Gary F
GF
D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002448:Cell Adhesion / Q000502:physiology*; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000494:pharmacology; D011134:Polysaccharides / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011817:Rabbits; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism*; D015044:Zona Pellucida / Q000737:chemistry / Q000378:metabolism
D016877:Oxidants; D011134:Polysaccharides; D011506:Proteins; D010504:Periodic Acid