title: 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.
authors.affiliation: Embryology Laboratory, Faculty of Biological Sciences, P. Catholic University of Chile, Santiago.
authors.forename: M
authors.initials: M
authors.lastname: Valdivia
authors.forename: R
authors.initials: R
authors.lastname: Yunes
authors.forename: J
authors.initials: J
authors.lastname: Melendez
authors.forename: A E
authors.initials: AE
authors.lastname: de Ioannes
authors.forename: L
authors.initials: L
authors.lastname: Leyton
authors.forename: M I
authors.initials: MI
authors.lastname: Becker
authors.forename: C
authors.initials: C
authors.lastname: Barros
mesh_terms: D000176:Acrosin / Q000378:metabolism*; D000177:Acrosome / Q000378:metabolism; D000818:Animals; D004792:Enzyme Precursors / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D011817:Rabbits; D013075:Sperm Capacitation / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; C022438:proacrosin; D000176:Acrosin