The involvement of beta-1,4-Galactosyltransferase and N-Acetylglucosamine residues in fertilization has been lost in the horse.
BACKGROUND
In human and rodents, sperm-zona pellucida binding is mediated by a sperm surface Galactosyltransferase that recognizes N-Acetylglucosamine residues on a glycoprotein ZPC. In large domestic mammals, the role of these molecules remains unclear: in bovine, they are involved in sperm-zona pellucida binding, whereas in porcine, they are not necessary. Our aim was to clarify the role of Galactosyltransferase and N-Acetylglucosamine residues in sperm-zona pellucida binding in ungulates. For this purpose, we analyzed the mechanism of sperm-zona pellucida interaction in a third ungulate: the horse, since the Galactosyltransferase and N-Acetylglucosamine residues have been localized on equine gametes.


METHODS
We masked the Galactosyltransferase and N-Acetylglucosamine residues before the co-incubation of gametes. Galactosyltransferase was masked either with an anti-Galactosyltransferase antibody or with the enzyme substrate, UDP Galactose. N-Acetylglucosamine residues were masked either with a purified Galactosyltransferase or with an anti-ZPC antibody.


CONCLUSIONS
The number of spermatozoa bound to the zona pellucida did not decrease after the masking of Galactosyltransferase or N-Acetylglucosamine. So, these two molecules may not be necessary in the mechanism of in vitro sperm-zona pellucida interaction in the horse.


CONCLUSIONS
The involvement of Galactosyltransferase and N-Acetylglucosamine residues in sperm-zona pellucida binding may have been lost during evolution in some ungulates, such as porcine and equine species.
Mugnier
Sylvie
S
INRA, UMR85 Physiologie de la Reproduction et des Comportements, CNRS, Haras Nationaux, Université de Tours, Nouzilly, France. sylvie.mugnier@tours.inra.fr
Boittin
Stéphane
S
Douet
Cécile
C
Monget
Philippe
P
Magistrini
Michèle
M
Goudet
Ghylène
G
D000117:Acetylglucosamine / Q000737:chemistry / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D005075:Biological Evolution; D002478:Cells, Cultured; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005615:Freezing; D006736:Horses / Q000235:genetics* / Q000502:physiology*; D008297:Male; D009237:N-Acetyllactosamine Synthase / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D012662:Semen Preservation; D013084:Sperm-Ovum Interactions / Q000187:drug effects / Q000276:immunology; D013094:Spermatozoa / Q000187:drug effects / Q000276:immunology; D014531:Uridine Diphosphate Galactose / Q000494:pharmacology; D015044:Zona Pellucida / Q000276:immunology / Q000378:metabolism
D000906:Antibodies; D014531:Uridine Diphosphate Galactose; D009237:N-Acetyllactosamine Synthase; D000117:Acetylglucosamine