Human sperm bind to the N-terminal domain of ZP2 in humanized zonae pellucidae in transgenic mice.
Fertilization requires taxon-specific gamete recognition, and human sperm do not bind to zonae pellucidae (ZP1-3) surrounding mouse eggs. Using transgenesis to replace endogenous mouse proteins with human homologues, gain-of-function sperm-binding assays were established to evaluate human gamete recognition. Human sperm bound only to zonae pellucidae containing human ZP2, either alone or coexpressed with other human zona proteins. Binding to the humanized matrix was a dominant effect that resulted in human sperm penetration of the zona pellucida and accumulation in the perivitelline space, where they were unable to fuse with mouse eggs. Using recombinant peptides, the site of gamete recognition was located to a defined domain in the N terminus of ZP2. These results provide experimental evidence for the role of ZP2 in mediating sperm binding to the zona pellucida and support a model in which human sperm-egg recognition is dependent on an N-terminal domain of ZP2, which is degraded after fertilization to provide a definitive block to polyspermy.
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA..
Boris
B
Baibakov
Nathan A
NA
Boggs
Belinda
B
Yauger
Galina
G
Baibakov
Jurrien
J
Dean
D000818:Animals; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C000606514:ZP1 protein, human; C000606515:ZP2 protein, human; D000072216:Zona Pellucida Glycoproteins; C000606519:Zp1 protein, mouse; C000606520:Zp2 protein, mouse