Greatwall Kinase Is Required for Meiotic Maturation in Porcine Oocytes1

Meiotic maturation in many species is initiated by the activation of maturation-promoting factor (MPF) with concomitant inactivation of counteracting phosphatases, most notably protein phosphatase 2A (PP2A). Recently, Greatwall (GWL) has been identified as a cell cycle regulator that inhibits PP2A a...

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Bibliographic Details
Published in:Biology of reproduction 2013-09, Vol.89 (3)
Main Authors: Li, Ying-Hua, Kang, Hyoeun, Xu, Yong-Nan, Heo, Young-Tae, Cui, Xiang-Shun, Kim, Nam-Hyung, Oh, Jeong Su
Format: Article
Language:English
Subjects:
cell cycle
Greatwall
GWL
meiosis
meiotic arrest
meiotic maturation
MPF
oocyte
oocyte maturation
PP2A
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Summary:Meiotic maturation in many species is initiated by the activation of maturation-promoting factor (MPF) with concomitant inactivation of counteracting phosphatases, most notably protein phosphatase 2A (PP2A). Recently, Greatwall (GWL) has been identified as a cell cycle regulator that inhibits PP2A activity. In this study, we demonstrate that GWL is required for meiotic maturation in porcine oocytes. GWL expression increases from germinal vesicle (GV) to metaphase II (MII) stages of porcine oocytes and dramatically decreases with progression of the meiotic cell cycle. GWL is initially localized in the nucleus of GV oocytes and is associated with spindle fibers following GV breakdown. Depletion of GWL inhibited or delayed meiotic maturation secondary to defects in chromosome congression and spindle formation. Conversely, overexpression of GWL overcame meiotic arrest and initiated progression to MII stage. However, these oocytes had severe spindle defects. Furthermore, MII oocytes depleted of GWL progressed to pronuclear formation. Taken together, our data demonstrate that GWL is required not only for meiotic maturation but also for maintenance of MII arrest in porcine oocytes.
ISSN:0006-3363
1529-7268
DOI:10.1095/biolreprod.113.109850