title: Zona pellucida modifications in the mouse in the absence of oocyte activation.
abstract: Mouse oocytes arrested in metaphase II exhibit zona hardening and a reduced fertilization rate after exposure to the cryoprotectant dimethylsulfoxide (Johnson J, In Vitro Fertil Embryo Transfer 6:168-175, 1989) but do not undergo parthenogenetic activation (Johnson and Pickering, Development 100:313-324, 1987). This paper shows that dimethylsulfoxide causes proteolytic modification of the zona pellucida glycoprotein ZP2 and inhibition of sperm binding. These effects of dimethylsulfoxide are caused by premature exocytosis of the cortical granules, a process that is initiated usually on fertilization. A model for the mechanism of action of dimethylsulfoxide is proposed based on the combined effects of cytoskeletal modification and osmotic shock. The presence of serum before and during the exposure to dimethylsulfoxide was found to reduce significantly these deleterious effects on the mouse zona pellucida without inhibiting the cortical granule release. These results highlight the suitability of dimethylsulfoxide as a tool to study the mechanisms leading to cortical granule release. Use of dimethylsulfoxide allows the separation of oocyte parthenogenetic activation from cortical granule release, and addition of serum allows separation of cortical granule release from the action of the cortical granule contents. Their use allows a dissection of the mechanisms underlying each of these three related events.
authors.affiliation: Department of Anatomy, University of Cambridge, England.
authors.forename: C
authors.initials: C
authors.lastname: Vincent
authors.forename: K
authors.initials: K
authors.lastname: Turner
authors.forename: S J
authors.initials: SJ
authors.lastname: Pickering
authors.forename: M H
authors.initials: MH
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001769:Blood; D015550:Cell Degranulation / Q000187:drug effects; D003594:Cytoplasmic Granules / Q000502:physiology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004527:Egg Proteins; D005260:Female; D005307:Fertilization in Vitro; D006023:Glycoproteins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008954:Models, Biological; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010312:Parthenogenesis / Q000187:drug effects; D011956:Receptors, Cell Surface; D013084:Sperm-Ovum Interactions / Q000187:drug effects; D013094:Spermatozoa / Q000378:metabolism; D015044:Zona Pellucida / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
chemical_list: D004527:Egg Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; C000606520:Zp2 protein, mouse; D004121:Dimethyl Sulfoxide