Immunolocalization of proacrosin/acrosin in rabbit sperm during acrosome reaction and in spermatozoa recovered from the perivitelline space

Abstract

The participation of acrosin in mammalian sperm penetration through the zona pellucida has been amply debated. In this paper we report the immunolocalization--by silver enhanced immunogold technique using ACRO-8C10 monoclonal antibody to human acrosin--of proacrosin/acrosin on ejaculated rabbit spermatozoa incubated in vitro in a capacitating medium and on spermatozoa recovered from the perivitelline space. After incubation in a capacitating medium, four different patterns were observed: (1) no labeling on acrosome intact spermatozoa; (2) labeling on the rim of the head; (3) labeling on the whole acrosome area; and (4) no labeling on acrosome reacted spermatozoa. At the start of incubation, spermatozoa with pattern 1 were the most abundant, whereas at the end of the 32 h incubation period, patterns 2 and 3 were the most frequent. On the other hand, 625 perivitelline spermatozoa were recovered from 17 fertilized rabbit eggs, of which 26% were labeled with the antiacrosin monoclonal antibody ACRO-8C10 in two different areas: (1) only on the equatorial region; and (2) only on the postacrosomal area. These results are consistent with the idea that proacrosin/acrosin remains associated to the acrosome reacted spermatozoa for long periods of time, and that proacrosin/acrosin associated to perivitelline spermatozoa could be responsible for the second penetration of fresh rabbit eggs by perivitelline spermatozoa.

Purification, Characterization, and N-Terminal Amino Acid Sequence of the Adenylyl Cyclase-Activating Protease from Bovine Sperm1

“…These data are consistent with the earlier observation that once ninhibin has been extracted from sperm particles it is not possible to extract much acrosin and vice versa [41]. Moreover, the data are consistent with recent studies using immunolocalization to determine the distribution of rabbit acrosin in spermatozoa during acrosome reaction, in which proacrosin/acrosin was found to be associated with the acrosome-reacted spermatozoa for long periods of time [42].…”

“…Stability for both ninhibin and acrosin was best at approximately pH 4.3, at which activities changed the least under these exposure conditions. These apparent differ- ences, though, may well have been due to the variable presence of inhibitors and consequently different sets of auto-activated intermediates [8,[13][14][15]42]. Crude and purified preparations of bovine acrosin and ninhibin were compared with regard to their electrophoretic mobility on an SDS-polyacrylamide gel (Fig.…”

Mammalian Fertilization Misread? Sperm Penetration of the Eutherian Zona Pellucida Is Unlikely to be a Lytic Event

“…But this has proven difficult too. Acrosin or proteinase precursor is readily detected within the acrosome and in the matrix/OAM complex of reacted spermatozoa, and sometimes on the equatorial segment of reacted sperm heads, probably through secondary adsorption [72][73][74][75][76][77][78]. Some PH-20 molecules apparently remain anchored in association with the naked IAM [79].…”

Acrosin release and acrosin activity during incubation in capacitating media using fresh and frozen-thawed dog sperm

“…Many studies have examined changes in acrosin and to some extent proacrosin that occur during or subsequent to the acrosome reaction and capacitation in several species (Harrison et al, 1982;Nuzzo et al, 1990;Valdivia et al, 1994;De los Reyes and Barros, 2000;Moreno et al, 2002;Gaboriau et al, 2007). However, the dog proacrosin/acrosin system has not been extensively studied.…”

“…44: 139-144, 2011 MATERIAL AND METHODS Unless specified, reagents were purchased from Sigma Chemical Co. (St. Louis, MO, USA) and Monoclonal antibody AcrC5F10 was purchased from BIOSONDA (Santiago, Chile). Production of the antibody has been described elsewhere (Valdivia et al, 1994).…”