Small Ubiquitin-Related Modifier-1 Programs Granulosa the Cell Apoptosis in Mice Ovary

The small ubiquitin-related modifiers (SUMO-1/2/3) have been in the limelight as crucial dictators of a spectrum of biological events including normal growth and development. SUMO-1 protein is important for post-translational modification which is required for a variety of biological processes including organ development and organelle biogenesis. However, its functional relevance in mammalian ovary still remains to be explored. Herein, we found that SUMO-1 consistently localizes in granulosa cells (GCs), oocytes and corpus luteum during mice folliculogenesis. Moreover, the SUMO-1 conjugates particularly those which molecular weight correspond to 34-, 43-, and 72 KDa were highly presented in ovaries and were dynamically influenced by PMSG and/or hCG administration, further buttressing that SUMO-1 was expressed in mouse ovary. Additionally, mutation at G96/97A (binding site) changed the localization of SUMO-1 from nucleus to both cytoplasm and nucleus. With some diffusion from nucleus into cytoplasm, and the apoptosis in GCs was significantly triggered by overexpression of both SUMO-1 and its mutant SUMO-1(G96/97A) with more significantly induced by the latter form. Over-expression of wild-type SUMO-1 and mutant SUMO-1(G96/97A) significantly induced (P<0.001) apoptosis in GCs, but the mutant SUMO-1 induced higher apoptotic rate (P<0.001) than over expressed SUMO-1. Overall, our study determines the expression of SUMO-1 in mouse ovary and pinpoints SUMO-1 as a determinant of GCs biology which is essential for mammalian ovary function. (C)2018 PVJ. All rights reserved