MEMBRANE MICRODOMAINS (RAFTS) AND FERTILIZATION

BOARELLI P; DE ROSAS J C; FORNES M W

Potrero de los Funes - San Luís

Congreso; SOCIEDAD DE BIOLOGIA DE CUYO. XXIV REUNION CIENTIFICA ANUAL 2006.; 2006

Sociedades de Biología de Cuyo.

Membrane microdomains (rafts) and fertilizationBoarelli, PV; De Rosas, JC; Fornès, MWLIAM – IHEM – Fac. Cs. Médicas – UNCuyo – CONICETpvboarelli@yahoo.com.ar Membrane microdomains (MD) are structures associated to specific functions and they are enriched in sphingolipids, cholesterol and proteins. These MD previously have been studied in diverse cellular models. The objectives of our work were the characterization of the MD components of the oocytes and their roll in the fertilization. In order to study the components of the MD, oocytes were incubated in HECM3. Later were fixed and marked: cholesterol by filipin III (FIII) and sphingolipids (GM1) by fraction beta cholera toxin (BCT). FIII is self-fluorescent and BCT is conjugated with Alexa Fluor(R). Samples were observed in a fluorescence microscope. In fecundation in vitro assay, we blocked lipids raft preincubating sperm with BCT (GM1) 15’. Then, mouse sperm were coincubated with hamster oocyte, and the sperm bounded were counted. Later, we blocked lipids of the MD in the oocytes and they were coincubated with spermatozoa non-blocking. First observations showed a binding decrement in sperm blocked with BCT (GM1) comparing with the control (not blocked). These results suggest that GMI, a classic raft component, and its redistribution after capacitation are involved in sperm – oocyte binding. However, in the blocked oocytes faced the sperm, they do not present a significant decrement