Germinal vesicle position and meiotic maturation in mouse oocyte.
During meiotic maturation, mammalian oocytes undergo an asymmetric division which is crucial for the formation of a functional gamete. In various organisms, accurate positioning of the nucleus before M-phase plays a major role in asymmetric cell divisions. However, the role of the position of the nucleus (or germinal vesicle, GV) during the prophase I arrest has not been investigated in mammalian oocytes. Here, we show that incompetent mouse oocytes possess a peripheral GV, while competent oocytes mainly exhibit a central position of the GV. At that time, the position of the GV correlates with the ability of the oocyte to complete meiotic maturation. Moreover, a lower efficiency in GV centering and a reduced ability to progress through meiosis are observed in oocytes from old mice. Thus, the position of the GV could be used as a simple morphological marker of oocyte quality.
Brunet
Stéphane
S
UMR 7622 Biologie du Développement, CNRS-UPMC, 9 quai St Bernard, 75005 Paris, France. sbrunet@snv.jussieu.fr
Maro
Bernard
B
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D002470:Cell Survival; D002478:Cells, Cultured; D005260:Female; D008322:Mammals / Q000502:physiology*; D008423:Maternal Age; D049469:Meiotic Prophase I; D051379:Mice; D009865:Oocytes / Q000648:ultrastructure*; D009866:Oogenesis / Q000502:physiology*