Localization of rabbit sperm acrosin during the acrosome reaction induced by immobilized zona matrix
1991
Richardson, R.T. | Nikolajczyk, B.S. | Abdullah, L.H. | Beavers, J.C. | O'Rand, M.G.
To better understand the loss of the acrosomal cap on the surface of the zona pellucida and the function of the equatorial-postacrosomal ion 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 spermatozoon-zona interaction. Induction of the acrosome reaction by zonae on coverstips (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 tonger associated with it. Further studies using zona-coated coverslips should lead to a more detailed understanding of the mechanism of zona penetration.
显示更多 [+] 显示较少 [-]