Involvement of MEK-mitogen-activated protein kinase pathway in follicle-stimulating hormone-induced but not spontaneous meiotic resumption of mouse oocytes

Journal:Biology of Reproduction

Place of Publication:USA

Key Words:developmental biology, FSH, kinases, meiosis, oocyte development, ovum, signal transduction

Abstract:Mitogen-activated protein (MAP) kinase has been reported to be activated during oocyte meiotic maturation in a variety of mammalian species. However, the mechanism(s) responsible for MAP kinase activation and the consequence of its premature activation during gonadotropin-induced oocyte meiotic resumption have not been examined. The present experiments were conducted to investigate the possible role of MAP kinase in FSH-induced and spontaneous oocyte meiotic resumption in the mouse. MAP kinase kinase (MAPKK, MEK) inhibitor, PD98059 or U0126, produced a dose-dependent inhibitory effect on both FSH-induced oocyte meiotic resumption and MAP kinase activation in the oocytes. However, the same inhibitor did not block spontaneous meiotic resumption of either denuded or cumulus cell-enclosed mouse oocytes, despite the activity of MAP kinase being totally inhibited. Immunoblotting the oocytes and the cumulus cells with the anti-active MAP kinase antibody showed that MAP kinase activity in the oocytes was detected at 8 h of FSH treatment, prior to germinal vesicle breakdown and increased as maturation progressed in the following culture period. In the cumulus cells, MAP kinase was activated even faster, its activity was detected at 1 h of FSH stimulation and increased gradually until 8 h of FSH treatment, then decreased and diminished after 12 h of FSH action. These data demonstrated that the MEK-MAP kinase pathway is implicated in FSH-induced but not spontaneous oocyte meiotic resumption.

All the Authors:S Rubinstein, A Luria, Y Lax

First Author:You-Qiang Su

Indexed by:RESEARCH ARTICLE

Correspondence Author:H Breitbart

Document Code:10.1095/biolreprod65.2.358

Volume:65

Issue:2

Page Number:358-365

ISSN No.:0006-3363

Translation or Not:no

Date of Publication:2001-08-01

Date of Publication:2001-08-01