title: Murine and human zona pellucida 3 derived from mouse eggs express identical O-glycans.
abstract: Murine sperm initiate fertilization by binding to the outer covering of the egg known as the murine zona pellucida (mZP). This binding is thought to require the interaction of O-glycans linked to a specific mZP glycoprotein (mZP3) with egg-binding proteins coating the sperm plasma membrane. The precise molecular basis of this interaction remains to be resolved. In this study, we analyzed the O-glycosylation of the individual mZP glycoproteins by using ultrasensitive MS methods. We found that the majority of the O-glycans that are linked to mZP3 are core type 2 sequences terminated with sialic acid, lacNAc (Galbeta1-4GlcNAc), lacdiNAc (Gal-NAcbeta1-4GlcNAc), Galalpha1-3Gal, and NeuAcalpha2-3[GalNAcbeta1-4]Galbeta1-4 (Sda antigen). Many of these terminal sequences have been implicated previously in murine sperm-egg binding. Core type 1 O-glycans are also present and are generally unmodified, although some are terminated with sialic acid, beta-linked N-acetylhexosamine, or NeuAcalpha2-3[GalNAcbeta1-4]Galbeta1-4. Eggs expressing human ZP (huZP) glycoprotein huZP3, derived from transgenic mice, bind murine but not human sperm, implying that huZP3 acquires the same O-glycans as native mZP3. Sequencing of huZP3-associated O-glycans confirms that this implication is correct. The data obtained in this investigation may prove to be very useful for studies to determine the precise molecular basis of initial murine sperm-egg binding.
authors.affiliation: Department of Biological Sciences, Imperial College London, London SW7 2AZ, United Kingdom. a.dell@ic.ac.uk
authors.forename: Anne
authors.initials: A
authors.lastname: Dell
authors.forename: Sara
authors.initials: S
authors.lastname: Chalabi
authors.forename: Richard L
authors.initials: RL
authors.lastname: Easton
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Haslam
authors.forename: Mark
authors.initials: M
authors.lastname: Sutton-Smith
authors.forename: Manish S
authors.initials: MS
authors.lastname: Patankar
authors.forename: Frank
authors.initials: F
authors.lastname: Lattanzio
authors.forename: Maria
authors.initials: M
authors.lastname: Panico
authors.forename: Howard R
authors.initials: HR
authors.lastname: Morris
authors.forename: Gary F
authors.initials: GF
authors.lastname: Clark
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D004527:Egg Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D010053:Ovary / Q000166:cytology / Q000502:physiology; D010063:Ovum / Q000502:physiology*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification; D011956:Receptors, Cell Surface; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013084:Sperm-Ovum Interactions; D000072216:Zona Pellucida Glycoproteins
chemical_list: D004527:Egg Proteins; D008562:Membrane Glycoproteins; D009842:Oligopeptides; D011134:Polysaccharides; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins