Inmunodetection of neural cadherin in bull spermatozoa

ARZONDO, MM; MARIN BRIGGILER, CI; CETICA, P; SALAMA, MF; VAZQUEZ LEVIN, M

Buenos Aires

Jornada; XI Jornadas Anuales de la Sociedad Argentina de Biología; 2009

Sociedad Argentina de Biología

Introduction: Epithelial (E-cad) and neural (N-cad) cadherin  proteins participate in cell-cell adhesion. Our group has characterized the expression of E-cad in bull sperm and its involvement in fertilization. However, no studies have been reported on the presence of N-cad in bull sperm. Aims: to immunodetect N-cad in frozen-thawed bull sperm. Methods: 1) N-cad protein sperm forms were identified; 2) N-cad localization patterns were characterized in non-capacitated (NC), heparin-capacitated (C-HEP) and its control (heparin + glucose: C-HGLU), and in A23187 Ca2+ ionophore-acrosome reacted sperm (R). To detect N-cad, the H-63 antibody (Sta Cruz Biotech) was used. Results & Discussion: In protein sperm extracts, the 135 kDa N-cad form was identified. In NC sperm, the main pattern (P1) (84±6; mean±SDM; n=36) showed a signal in the acrosomal and postacrosomal regions. Similar results were obtained with sperm incubated with H-63 prior to fixation. In C-HEP sperm, P1 was preponderant (63±9; n=21) but lower, with more cells with staining only in the acrosomal (P2) or postacrosomal (P3) regions. This shift was not found in C-HGLU sperm (P1: 82±18). In R-sperm suspensions, a staining pattern in the equatorial segment (P4) was observed (R: 22±6; control: 1±1; n=21). Over 90% of P4 cells were classified as R after co-localization with Pisum sativum agglutinin. This is the first report on bull sperm N-cad expression and its localization in cell regions involved in gamete interaction.