Translator Disclaimer
1 March 2006 Study of Germinal Vesicle Requirement for the Normal Kinetics of Maturation/M-Phase-Promoting Factor Activity During Porcine Oocyte Maturation
Author Affiliations +
Abstract

Mammalian immature oocytes contain large nuclei referred to as germinal vesicles (GVs). The translocation of maturation/M-phase promoting factor (MPF) into GVs just before the activation of MPF has been reported in several species. To examine whether the GV is required for MPF activation in mammalian oocytes, porcine immature oocytes were enucleated and their MPF activity and CCNB (also known as cyclin B) levels were investigated. The activation of MPF at the start of maturation was detected at normal levels in enucleated oocytes, whereas reactivation to induce the second meiosis was not observed. Although protein synthesis was found to be normal both qualitatively and quantitatively, even in the absence of the nucleus, CCNB1 did not sufficiently accumulate in the enucleated oocytes. The defects in the enucleated oocytes were reversed by the injection of GV material into the enucleated oocytes. Furthermore, the inhibition of CCNB1 degradation revealed drastic accumulation of CCNB1, indicating active synthesis of CCNB1 in enucleated oocytes. The mitogen-activated protein kinase cascade remained unaffected by enucleation. These results indicate that GV is not required for the activation of MPF during the first meiosis, but that it is required for the second meiosis because of its promotion of CCNB1 accumulation.

Koji Sugiura, Kunihiko Naito, Tsutomu Endo, and Hideaki Tojo "Study of Germinal Vesicle Requirement for the Normal Kinetics of Maturation/M-Phase-Promoting Factor Activity During Porcine Oocyte Maturation," Biology of Reproduction 74(3), 593-600, (1 March 2006). https://doi.org/10.1095/biolreprod.105.046375
Received: 5 August 2005; Accepted: 1 November 2005; Published: 1 March 2006
JOURNAL ARTICLE
8 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top