Biological characterization of a component (gp39) of the oocyte vitelline envelope in Bufo arenarum

BARRERA, DANIEL; GARCÍA, E. VANESA; MICELI, DORA C.

Buenos Aires

Jornada; X Jornadas de la Sociedad Argentina de Biología; 2008

Sociedad Argentina de Biología

In amphibians, the first portion of the oviduct or pars recta (PR) synthesizes and secretes a serine protease called oviductin. This enzyme produces a limited proteolysis of glycoproteins of the oocyte vitelline envelope (VE) during their transit through the PR. In consequence, the oocytes can be fertilizable by homologous sperm apparently by the exposure of sperm-binding sites on VE. Previous studies showed that oviductin action increases the relative amount of a VE glycoprotein of 39 kDa (gp39) and sequence analysis revealed that gp39 could be member of the ZPC proteins family. The aim of this work was to analyze if B. arenarum gp39 is involved in gamete interaction. For this purpose, spermatozoa were incubated with biotin conjugated VE glycoproteins. Also, we tested the sperm binding capacity to gp39 using antibodies generated against this gp in inmunocytochemical and inhibition of fertilization assays. The results showed that in vitro the sperm bind labeled gp39. Furthermore, the inhibitory effect of antibodies on fertilization indicated that gp39 might participate in sperm binding. Thus, considering the results obtained, it seems probable that B. arenarum gp39 is involved in the sperm adhesion mechanism to the oocyte envelope during fertilization.