SPERM BINDING TO A VITELLINE ENVELOPE COMPONENT (GP 39) OF BUFO ARENARUM OOCYTE.

BARRERA, DANIEL; GARCÍA, ELINA VANESA; MICELI, DORA CRISTINA

Tafí del Valle-Tucumán

Jornada; XXIV Jornadas Científicas de la Asociación de Biología de Tucumán; 2007

Asociación de Biología de Tucumán

In Bufo arenarum fertilization, the vitelline envelope (VE) has an active participation in the gamete interaction. The first portion of the oviduct, Pars Recta (PR), synthesizes and secrets the serine protease oviductin. This enzyme produces specific and limit proteolysis of some glycoprotein components of the VE which might expose sperm binding sites. It was demonstrated that sperm binding, penetration and subsequent gamete fusion are improved by oviductin. The VE is composed for at least six glycoproteins : GP 122, 82, 48, 42, 39 and GP 34. In previous experiments we demonstrated that GP 39 shares common amino acid sequences with ZPC glycoprotein family. In order to discern whether the spermatozoa binds specifically to GP39 or not, we have obtained a polyclonal antibody against this purified GP. In vitro assay was developed for this aim: 150 ul of dissolved VE proteins (150 ug P) was incubated with 50 ul sperms suspension (7x107 sperm in the mixture reaction). The GP39 ?sperm binding was observed by immuno-citochemical assayed with biotin labeled second antibody and extravidin-FITC as amplifier. The label over sperm acrosome membrane was observed. This indicated specific binding of GP39. Given that GP39 belong to ZPC family and its concentration is increased in VE after oviductin action, its participation in the earlier fertilization event is feasible.