title: Localization of rabbit sperm acrosin during the acrosome reaction induced by immobilized zona matrix.
abstract: To better understand the loss of the acrosomal cap on the surface of the zona pellucida and the function of the equatorial-postacrosomal region after the acrosome reaction, we have constructed an in vitro system using heat-solubilized zonae pellucidae dried onto a coverslip and incubated with capacitated spermatozoa. This system allows good optical resolution of spermatozoonzona interaction. Induction of the acrosome reaction by zonae on coverslips (30%) is comparable to the induction of the reaction reported previously for rabbit spermatozoa using solubilized zonae in solution. Antiserum to rabbit proacrosin, antiserum to a porcine 49-kDa proacrosin fragment, and antiserum to a porcine 14-kDa C-terminal acrosin fragment were utilized to monitor the acrosome reaction. Rabbit proacrosin/acrosin is not present on the surface of live, acrosome-intact, swimming spermatozoa. After contact with zona, the acrosome reaction begins and proacrosin/acrosin becomes available to bind antibody, first as a crescent in the apical region and then more posteriorly until the entire anterior acrosome is labeled. Proacrosin/acrosin remains on the equatorial and postacrosomal regions of acrosome-reacted spermatozoa and also remains associated with the acrosomal cap even after the spermatozoon is no longer associated with it. Further studies using zona-coated coverslips should lead to a more detailed understanding of the mechanism of zona penetration.
authors.affiliation: Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
authors.forename: R T
authors.initials: RT
authors.lastname: Richardson
authors.forename: B S
authors.initials: BS
authors.lastname: Nikolajczyk
authors.forename: L H
authors.initials: LH
authors.lastname: Abdullah
authors.forename: J C
authors.initials: JC
authors.lastname: Beavers
authors.forename: M G
authors.initials: MG
authors.lastname: O'Rand
mesh_terms: D000176:Acrosin / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D000177:Acrosome / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D007106:Immune Sera / Q000276:immunology; D008297:Male; D010446:Peptide Fragments / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D004792:Enzyme Precursors; D007106:Immune Sera; D010446:Peptide Fragments; C022438:proacrosin; D000176:Acrosin