ABSTRACT
Mammalian oocyte meiosis is a special form of cell division that provides haploid gametes for fertilization. Unlike in mitosis, post-translational modifications (PTMs) are more crucial during meiosis because of the absence of de novo mRNA transcription. As a classic PTM, protein neddylation is a biological process that mediates protein degradation by modifying cullin proteins and activating the Cullin-Ring E3 ligases. This process plays important roles in various biological processes such as autophagy and tumorigenesis. However, the function of neddylation in germ cells is unknown. In this study, we observed that the inhibition of neddylation by its specific inhibitor MLN4924 significantly arrests mouse oocyte at the stage of metaphase during meiosis. The arrested oocytes display impaired spindles with over-activation of spindle assembly checkpoint (SAC). Accordingly, we identified early mitosis inhibitor 1 (Emi1), a key inhibitor of anaphase-promoting complex/cyclosome (APC/CFzr1), as a substrate of neddylation-mediated protein degradation. Thus, our study uncovered an unknown role of neddylation in female germ cells and suggests that proper neddylation is essential for oocyte maturation.
Subject(s)
Cell Cycle Checkpoints/drug effects , Cyclopentanes/pharmacology , Meiosis/drug effects , NEDD8 Protein/antagonists & inhibitors , NEDD8 Protein/metabolism , Oocytes/drug effects , Protein Processing, Post-Translational/drug effects , Pyrimidines/pharmacology , Animals , Antibodies, Monoclonal/pharmacology , Cells, Cultured , Down-Regulation/drug effects , Down-Regulation/genetics , Female , Mice , Mice, Inbred ICR , NEDD8 Protein/genetics , Oocytes/physiology , Oogenesis/drug effects , Oogenesis/genetics , Protein Processing, Post-Translational/genetics , RNA, Small Interfering/pharmacology , Ubiquitination/drug effects , Ubiquitination/geneticsABSTRACT
Infertility has been a great challenge in reproductive medicine. At least 40% of human pregnancy losses are clinically unrecognized and occur because of embryo implantation failure. Identification of the proteins and biochemical factors involved in embryo implantation and that are essential for crosstalk between the embryo and uterus can further increase female fertility rates. The actin cytoskeleton and actin-binding proteins (ABPs) are of great importance for cell morphology and rearrangement, which is crucial for trophoblast adhesion and invasion. However, the research on ABPs in embryo implantation is insufficient. In this report, we found that transgelin (TAGLN)2 is highly expressed in mouse blastocyst trophoblasts. Notably, inhibition of mouse blastocyst trophoblast TAGLN2 by lentivirus-mediated RNA interference significantly impaired embryo adhesion and implantation ability. Further in vitro experiments demonstrated that TAGLN2 knockdown with small interfering RNA observably decreased the invasion and migration abilities of human trophoblast cells. Immunofluorescence colocalization and microscale thermophoresis analysis showed that TAGLN2 directly binds to actin. In addition, knockdown of TAGLN2 in trophoblast cells resulted in a remarkable reduction in F-actin rather than G-actin. Our findings reveal an unidentified role of TAGLN2 in regulation of trophoblast invasion and adhesion by promoting actin polymerization.-Liang, X., Jin, Y., Wang, H., Meng, X., Tan, Z., Huang, T., Fan, S. Transgelin 2 is required for embryo implantation by promoting actin polymerization.
