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Possible Involvement of Phosphatidylinositol 3-Kinase, but Not Protein Kinase B or Glycogen Synthase Kinase 3β, in Progesterone-Induced Oocyte Maturation in the Japanese Brown Frog, Rana japonica
Title: | Possible Involvement of Phosphatidylinositol 3-Kinase, but Not Protein Kinase B or Glycogen Synthase Kinase 3β, in Progesterone-Induced Oocyte Maturation in the Japanese Brown Frog, Rana japonica |
Authors: | Ota, Ryoma Browse this author | Suwa, Kaori Browse this author | Kotani, Tomoya Browse this author | Mita, Koich Browse this author | Yamashita, Masakane Browse this author |
Keywords: | amphibians | oocyte maturation | phosphatidylinositol 3-kinase | progesterone | signal transduction |
Issue Date: | Jul-2008 |
Publisher: | Zoological Society of Japan |
Journal Title: | Zoological Science |
Volume: | 25 |
Issue: | 7 |
Start Page: | 773 |
End Page: | 781 |
Publisher DOI: | 10.2108/zsj.25.773 |
PMID: | 18828666 |
Abstract: | It is known that amphibian oocytes undergo maturation through the formation and activation of maturation-promoting factor (MPF) in response to stimulation by the maturation-inducing hormone progesterone; however, the signal transduction pathway that links the hormonal stimulation on the oocyte surface to the activation of MPF in the oocyte cytoplasm remains a mystery. The aim of this study was to investigate whether the signal transduction mediated by phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB), and glycogen synthase kinase 3β (GSK3β) is involved in progesterone-induced oocyte maturation in the Japanese brown frog, Rana japonica. Inhibitors of PI3K, wortmannin and LY294002, inhibited progesterone-stimulated germinal vesicle breakdown (GVBD) only when the oocytes were treated at the initial phase of maturation, suggesting that PI3K is involved in the progesterone-induced maturation of Rana oocytes. However, we also obtained results suggesting that PKB and GSK3β are not involved in Rana oocyte maturation. A constitutively active PKB expressed in the oocytes failed to induce GVBD in the absence of progesterone despite its high level of kinase activity. A Myc-tagged PKB expressed in the oocytes (used to monitor endogenous PKB activity) was not activated in the process of progesterone-induced oocyte maturation. Overexpression of GSK3β, which is reported to retard the progress of Xenopus oocyte maturation, had no effect on Rana oocyte maturation. On the basis of these results, we propose that PI3K is involved in the initiation of Rana oocyte maturation, but that neither PKB nor GSK3βis a component of the PI3K signal transduction pathway. |
Rights: | (c) Zoological Society of Japan / 本文献の公開は著者の意思に基づくものである |
Relation: | http://www.bioone.org/perlserv/?request=get-archive&issn=0289-0003 |
Type: | article |
URI: | http://hdl.handle.net/2115/39623 |
Appears in Collections: | 生命科学院・先端生命科学研究院 (Graduate School of Life Science / Faculty of Advanced Life Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 山下 正兼
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