Txndc9 Is Required for Meiotic Maturation of Mouse Oocytes.

Fanhua Ma,Liming Hou,Liguo Yang

doi:10.1155/2017/6265890

Fanhua Ma, Liming Hou + Show 1 more

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https://doi.org/10.1155/2017/6265890

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Abstract

Txndc9 (thioredoxin domain containing protein 9) has been shown to be involved in mammalian mitosis; however, its function in mammalian oocyte meiosis remains unclear. In this study, we initially found that Txndc9 is expressed during meiotic maturation of mouse oocytes and higher expression of Txndc9 mRNA and protein occurred in germinal vesicle (GV) stage. By using confocal scanning, we observed that Txndc9 localized at both nucleus and cytoplasm, especially at spindle microtubules. Specific depletion of Txndc9 by siRNA in mouse oocyte resulted in decreasing the rate of first polar body extrusion and increasing abnormal spindle assemble. Moreover, knockdown of Txndc9 in germinal vesicle (GV) stage oocytes led to higher level of reactive oxygen species (ROS) and lower level of antioxidant glutathione (GSH) as compared with control oocytes, which indicated that Txndc9 may be involved in mediating the redox balance. In summary, our results demonstrated that Txndc9 is crucial for mouse oocyte maturation by regulating spindle assembly, polar body extrusion, and redox status.

Highlights

In vitro maturation (IVM) of oocytes as a very valuable artificial reproductive technology plays an important role in the fields of reproductive and developmental biology [1]
Germinal vesicle (GV), germinal vesicle breakdown (GVBD), Metaphase I (MI), Anaphase/Telophase I (ATI), and Metaphase II (MII) stages mouse oocytes were collected after being cultured in M16 medium for 0, 4, 8, 9.5, or 14 h, respectively
Reverse Transcription (RT)-qPCR result indicated that Txndc9 mRNA is expressed from GV to MII stage and the highest Txndc9 mRNA level occurred at GV stage (Figure 1(a))

Summary

Introduction

In vitro maturation (IVM) of oocytes as a very valuable artificial reproductive technology plays an important role in the fields of reproductive and developmental biology [1]. During mammalian oocytes growth and maturation, both nucleus and cytoplasm maturation events are coordinated, including resumption of meiosis, proper spindle assembly, and polar body extrusion [2]. During these processes, rearrangement of organelles, cytoskeletal microtubules, and associated motor proteins such as dynein, dynactin, and kinesin participated [3]. Microtubule assembly and dynamics of microtubule polymerization require many proteins, which are crucial for correct and efficient formation of tubulin heterodimer; afterwards a wide array of binding proteins and modifying enzymes further regulate microtubule function [4] Any error in this process can result in the generation of aneuploid eggs. Fertilization of aneuploid eggs in humans is a major cause of pregnancy loss and infertility [5]

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