Inhibition of mouse in vitro fertilization by an antibody against a unique 18-amino acid domain in the polysulfate-binding domain of proacrosin/acrosin.
OBJECTIVE
To determine the contribution of the polysulfate-binding domain (PSBD) of acrosin during sperm penetration.


METHODS
To inhibit the in vitro fertilization of mouse zona-intact oocytes by using a polyclonal antibody raised against an 18-amino acid peptide of proacrosin (anti-PSBD).


METHODS
Unit of Reproduction and Development, Faculty of Biological Sciences, Pontifical Catholic University of Chile.


METHODS
None.


METHODS
A polyclonal antibody against the 43IFMYHNNRRYHTCGGILL(60) peptide was raised in New Zealand female rabbits. The specificity of the antibody was evaluated by an ELISA. Zona-intact mouse oocytes were coincubated with capacitated spermatozoa for 3 hours in the presence of 0.63 mg/mL of the antibody or preimmune serum. As a control, we used zona-free mouse oocytes under the same experimental conditions.


METHODS
We evaluated the fertilization rate of zona-intact and zona-free mouse oocytes by phase-contrast microscopy. An oocyte was considered fertilized when at least one decondensed sperm head was found within the egg cytoplasm. We evaluated 50-60 mouse oocytes in each group in three independent experiments.


RESULTS
The anti-PSBD antibody inhibited the fertilization of zona-intact, but not zona-free, mouse oocytes, by capacitated spermatozoa. In addition, the binding of the anti-PSBD to proacrosin/acrosin in a solid-phase assay was inhibited in the presence of polysulfates (fucoidan).


CONCLUSIONS
The anti-PSBD directed against the PSBD of proacrosin/acrosin inhibited the penetration of capacitated mouse spermatozoa through the zona pellucida. This antibody may be a useful tool to define the roles of the different domains of proacrosin/acrosin during gamete interaction.
Moreno
Ricardo D
RD
Unit of Reproduction and Development, Faculty of Biological Sciences, Pontifical Catholic University of Chile, Santiago, Chile. rmoreno@genes.bio.puc.cl
Bustamante
E
E
Schatten
G
G
Barros
C
C
D000176:Acrosin / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites / Q000276:immunology; D004792:Enzyme Precursors / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D005260:Female; D005306:Fertilization / Q000502:physiology; D005307:Fertilization in Vitro; D005455:Fluorescent Antibody Technique; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology*; D011134:Polysaccharides / Q000378:metabolism; D013075:Sperm Capacitation; D013431:Sulfates / Q000378:metabolism*; D015044:Zona Pellucida / Q000502:physiology
D000906:Antibodies; D004792:Enzyme Precursors; D010446:Peptide Fragments; D011134:Polysaccharides; D013431:Sulfates; C007789:fucoidan; C022438:proacrosin; D000176:Acrosin