Role of Alpha-SNAP in female fertility: lessons from a spontaneous mutant mouse.

BATIZ, LUIS FEDERICO; DE PAOLA, MATILDE; MICHAUT, MARCELA A.

Concon

Congreso; XXIX Reunión Anual de la Sociedad Chilena de Reproducción y Desarrollo; 2018

Sociedad Chilena de Reproducción y Desarrollo

In most mammals, the main mechanism that prevents polyspermy during fertilization is the cortical reaction. Cortical reaction is triggered by the sperm and consists in the secretion of the content of the cortical granules. The membranes of the cortical granules fuse with the plasma membrane of the oocyte. Several studies have suggested that this fusion of membranes is mediated by the SNAREs proteins. The aim of our work was to identify and characterize the alpha-SNAP protein in mouse oocytes and its implication in female fertility. In a first stage, we worked with oocytes from CF1 females. Results of RT-PCR, Western blot and immunofluorescence showed that alpha-SNAP is present in oocytes and it is localized mainly in the cortical region enriched in cortical granules. Through a functional assay that allows evaluating the function of the protein in the cortical reaction, we demonstrated that alpha-SNAP regulates the cortical reaction in mouse oocytes activated parthenogenetically. In a second stage, we analyzed the fertility of the hyh females (hydrocephalus with hop gait), which present a point mutation in the alpha-SNAP gene. In vitro fertilization assays (IVF) showed that the IVF rate was lower for hyh oocytes with a significant increase in the polyspermy rate. The functional analysis of the cortical reaction showed that hyh oocytes have an altered secretion of their cortical granules. Our results reveal that alpha-SNAP plays a fundamental role in female fertility.