title: Involvement of a sperm protein sensitive to sulfhydryl-depleting reagents in mouse sperm-egg fusion.
abstract: Effects of various sulfhydryl (SH)-depleting reagents on sperm-egg fusion were demonstrated. When sperm were treated with three plasma membrane-permeable SH-depleting reagents, N-ethyl-maleimide, sodium tetrathionate and 5,5'-dithiobis (2-nitro-benzoic acid), the rates of cleavage of eggs were significantly lower than those with control sperm. Neither the motility, penetration of the zona pellucida, acrosomal status of the sperm, nor sperm-egg binding was affected by the SH-depleting reagents. Fusion of sperm and zona-free egg was estimated by the sperm nuclear incorporation into the eggs, intracellular calcium mobilization, and cortical granule exocytosis in the eggs. Sperm-egg fusion was blocked dose-dependently when sperm were exposed to membrane-permeable SH-depleting reagents, but was not blocked by a membrane-impermeable SH-depleting reagent, eosin-5-maleimide. Blockage of fusion by sodium tetrathionate was completely reversed by an SH-reductant, dithiothreitol. These results suggest that a protein which is sensitive to SH-depleting reagents may play an important role in mouse sperm-egg fusion and that the functional SH region of the protein may be located at an intracellular site.
authors.affiliation: Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mammoto
authors.forename: N
authors.initials: N
authors.lastname: Masumoto
authors.forename: M
authors.initials: M
authors.lastname: Tahara
authors.forename: M
authors.initials: M
authors.lastname: Yoneda
authors.forename: T
authors.initials: T
authors.lastname: Nishizaki
authors.forename: K
authors.initials: K
authors.lastname: Tasaka
authors.forename: A
authors.initials: A
authors.lastname: Miyake
mesh_terms: D000177:Acrosome / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects; D002463:Cell Membrane Permeability; D003594:Cytoplasmic Granules / Q000502:physiology; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D013094:Spermatozoa / Q000187:drug effects*; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D013776:Tetrathionic Acid / Q000494:pharmacology; D015044:Zona Pellucida / Q000502:physiology
chemical_list: D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D013776:Tetrathionic Acid; D004228:Dithionitrobenzoic Acid; D005033:Ethylmaleimide; D002118:Calcium