RAFT: New Membrane Microdomains in Mouse Sperm

FORNES M.W.; BOARELLI PAOLA VANINA; CATTANEO C.B.; VINCENTI A.E; MONCLUS M.A.

Mendoza, Argentina

Simposio; Reunión Conjunta de: XXI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 10° Aniversario de BIOCELL y Reunión Fundacional de la Sociedad Argentina de Microscopía; 2003

Sociedad de Biología de Cuyo, Sociedad Argentina de Microscopía

Plasmatic membrana plays a critical role in sperm function. Acrosomal reaction, sperm capacitation and fertilization dependo n specific membrana domains. Recently it was fosussed the role of rafst domains. Sphingolipids, colesterol and specific proteins are present in these small microdomains and some of them have specific function in sperm live e.g. cholesterol lost has been envolved in sperm capacitation. But the exact arraignment and distribution during spermatogenesis. maturation and capacitation of sperm raft remains nuclear. In this paper we colocaliza the three raft components: Colesterol, sphingolipids and rafts proteins during spermiogenesis , maturation and capacitation. Colesterol was recognized by specific marker, Filipin. It is self fluorescent and also produce an ultrastructural modification of plasma membrana that could observe by freeze-fracture ethodology. Sphingolipids, GM1, was rcognized specifically by fraction b of cholera toxin (b CT) conjugated with alexa fluor. Protein, Caveolin1 was recognized by specific mab follow by secondary Ab coupled with FIAC. Fixed sperm isolated from inicial and final epididymal regions, paraffin testis sections and capacitated or not, Mouse sperm were procesed for fluorescent studies, observed in an invertid Nikon microscope and digital Picture by Metamorph software. GM1, colesterol and Caveolin1 were colocalized over the acrosomal regions of mature or mon-capacitated sperm. But capacitated ones, lost filipin fluorescente label, and a relocation of b CT –at the post acrosomal region – was verified. During spermatogenesis raft components were progresively located at the cell surface regions.