Molecular identification and localization analysis of SNAPS and NSF during mouse oocyte maturation

DE PAOLA, MM; GALLO, GL; MAYORGA, LS; MICHAUT, M.A.

Mendoza

Congreso; 48º SAIB; 2012

SAIB

In mammals, the primary mechanism in preventing polyspermic fertilization involves cortical granules exocytosis (CGE). Several studies have suggested that CGE is a SNARE protein-mediated pathway; however, the molecular characterization of CGE is still incomplete. We hypothesized that the oocyte uses the same conserved membrane fusion machinery as neurons and human sperm, and the regulatory complex SNAP/NSF is present in mouse oocyte. We first investigated the expression of SNAP isoforms: , ß, and , and NSF by RT-PCR. The results show that the - and - SNAP(but not ß), and NSF are expressed in mouse oocyte. Western blot analyses indicate that these proteins are present during oocyte maturation and egg activation showing no variations between the different stages. Indirect immunofluorescence experiments revealed that -SNAP and NSF localized mainly in the cortical region of all stages analyzed. While -SNAP had a similar distribution that -SNAP, this protein also showed a cytoplasmic distribution in immature oocytes. All identified proteins: -SNAP, -SNAP, and NSF are predominately observed in the cortical region, which is enriched in cortical granules at the mature oocyte, suggesting that these proteins may be involved in CGE. However, more studies are needed to elucidate if both -SNAP and -SNAP are equally important in CGE or have different functions in mouse oocyte