Growth Arrest Specific Gene 6 Improved in vitro Maturation of Oocytes and the Development Potential of Porcine Embryo after Parthenogenetic Activation

Abstract

In this study, expression pattern-and function of growth arrest specific gene 6 (Gas6) during porcine oocyte maturation and early embryonic development were systemically investigated. The expression of Gas6 in the process of follicular development was studied by immunohistochemical staining, immunofluorescence, QRT-PCR and western blot. Immunohistochemical staining results showed that Gas6 was expressed in the oocytes, especially the nucleus, from the primary to preovulatory stages. The further immunofluorescence results showed that Gas6 was expressed thoughout the in vitro matured porcine oocytes, and the staining signal decreased in the first 12 h but then increased during the process of oocyte maturation. QRT-PCR analysis revealed that Gas6 mRNA was continuously expressed during the process of oocyte maturation, disappeared after parthenogenetic activation, re-appeared and elevated in the blastocysts stage. The following western blot analysis revealed a similar expression pattern with QRT-PCR and immunofluorescence. In conclusion, the expression pattern of Gas6 gene is closely related to oocytes maturation and embryo development. Gas6 may play a crucial role in the process of oocytes maturation and improve the development potential of early embryos by promoting the cytoplasmic maturation.