CONICET | Buscador de Institutos y Recursos Humanos

DYS/FXYD5EXPRESSION IN HUMAN AND MURINE TESTIS AND SPERMATOZOA. CO-LOCALIZATION STUDIES WITHEPITHELIAL CADHERIN AND ACTINSzapiro GJ, Besso MJ, Rosso M,Veiga MF, Marín-Briggiler CI, Vazquez-Levin MH. IBYME-CONICET-UBA, Buenos Aires, Argentina. (mhvazl@gmail.com)Dysadherin (Dys) is a cell membrane glycoprotein overexpressed in human tumors.It acts as a negative modulator of epithelial cadherin (Ecad), at least in part,by competing for the actin cytoskeleton. The murine homologue, FXYD5, isexpressed in normal adult mouse tissues. Our group has reported Ecad expressionin the male reproductive tract and spermatozoa in both human and murine species,and its participation in gamete interaction. The aim of the study was to evaluate Dys/FXDY5 expressionin human and murine testis and spermatozoa and its co-localization with Ecadand actin in the male gamete. Methodsinvolved 1)RT-PCR to detect transcripts, 2)SDS-PAGE/Western-Immunoblottingto immunodetect protein forms in cell and tissue extracts, 3)Immunohistochemistryto assess protein expression in the testis, 4)Fluorescence microscopy tocharacterize Dys/FXYD5 localization and co-localization with Ecad and actin/filamentousactin using antibodies and probes. Dys/FXYD5 was detected in both species: mRNAexpression in testis, protein forms in testis (human= 91KDa; murine = 75-66KDa) and sperm (human= 91KDa; murine= 35 and 66 kDa). A specific signal wasfound in the acrosome of testicular spermatids, the acrosome and flagellum ofejaculated (human) and cauda epididymis(murine) spermatozoa. Dys/FXYD5-actin and Dys/FXYD5-Ecad co-localized in the spermacrosomal region. Based on these findings, we propose Dys/FXYD5 as a modulator ofEcad-mediated adhesion by mechanisms involving competition for the actin cytoskeleton.Supported by a grant from CONICET(PIP2120) to MHVL.

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