Presence of E- and N-cadherin in mouse gametes. Evaluation of their participation in fertilization

MARIN BRIGGILER, CLARA I; CAPECE, LORENA; LENTZ, EZEQUIEL; RIVERO, CINTIA; BUSSO, DOLORES; VEAUTE, CAROLINA; VAZQUEZ LEVIN, MÓNICA

Buenos Aires

Congreso; Reunión Anual de la Sociedad Argentina de Biología; 2003

PRESENCE of E- and N-cadherin in MOUSE gametes. evaluation of their participation in fertilization. Marín-Briggiler C, Capece L, Lentz E, Rivero C, Busso D, Veaute C, Vazquez-Levin M. IBYME-CONICET. Buenos Aires, Argentina.   Cadherins (cad) constitute a superfamily of adhesion molecules that mediate cell recognition. Several evidence suggest their participation in sperm-oocyte interaction. Objetive: 1) to immunolocalize E- and N-cad in mouse gametes; 2) to evaluate their participation in fertilization; 3) to determine E-cad molecular forms in protein extracts; and 4) to evaluate presence of E-cad epididymal transcripts. Material and Methods: 1) immunocytochemical studies were done in oocytes and in 2-h capacitated sperm with antiE- and antiN-cad antibodies; 2) in vitro fertilization (IVF) assays were carried out with sperm preincubated with 20 mg/ml of specific antibodies; 3) molecular forms of E-cad were detected in protein extracts subjected to 10% PAGE followed by Western inmunoblotting; 4) RT-PCR analysis was performed with E-cad specific primers. Results: 90% of the sperm were immunoreactive to E-cad, showing staining over the equatorial segment (60%) alone or in addition to a signal over the acrosome (30%). N-cad staining was detected in the acrosomal cap of  90% of the cells. At least 40% of the oocytes were immunoreactive to E-cad and N-cad. Sperm preincubation with antiE-cad significantly inhibited the IVF rate (antiE-cad: 37+20 %, Control: 63+18 % fertilized oocytes; p<0.05). Contrasting, preincubation with antiN-cad had no effect upon IVF. While protein sperm extracts revealed two E-cad forms (127 and 108 kDa), a 127-kDa form was detected in the epididymis. RT-PCR analysis showed the presence of E-cad transcript in this tissue. Conclusions: Expression of epididymal E-cad was confirmed by RNA and protein analysis. Localization of E-cad in fusogenic domains of both gametes and the inhibitory effect of antiE-cad antibodies upon fertilization strongly suggest its participation in sperm-oocyte interaction.