UNMASKING OF AN INTRAMEMBRANEOUS PROTEIN IN GUINEA PIG SPERM DURING EPIDIDYMAL TRANSIT

BURGOS MH.; FORNES MW.; VINCENTI AE.

San Luis

Congreso; 7mo Congreso Argentino de Ciencias Morfológicas; 1996

Universidad del Salvador

Mammalian spermatozoa display morphological, physiological and molecular changes during epididymal transit. In the guinea pig sperm an intramembranous protein originated in the testis and active in intergametic fusion was followed during the transit and identified with monoclonal antibody (PH30. Primakoff et al., J Cell Biol, 1987, 104:141). This protein was identified with immunocytochemical reactions applied to epididymis fixed by vascular perfusion with PAF (picric acid ? formalin) in each animal one epididymis was embedded in paraffin sectioned for light microscopy and treated with the antibody peroxidase reaction and the other, after plastic embedding and thin sections, was treated with the monoclonal antibody with gold for electron microscopy (TEM). This technique was also applied to freeze fracture replicas. In coincidence with the epididymal peristaltic waves and the intimate contact of spermatozoa with the epithelial stereocilia the unmasking of PH30 protein was observed to start at the level of the second portion of the corpus epididymis and localized in the postacrosomal region of the spermatozoon. This unmasking increases during the epididymal transit from 51% at the end of corpus to 98% in the caudal portion. Spermatozoa from caput epididymis which are negative to the antibody reaction, after 3 min treatment with trypsin 0,1 mg/ml become positive with the same localization in the postacrosomal region. We concluded that during contact of epithelial stereocilia with spermatozoa occurs the unmasking by a trypsin like action as a new evidence of a gamete-epididymal interaction. We gratefully acknowledge to Diana Myles the PH30 antibody. This work was supported by CONICET and CIUNC.