원문정보
초록
영어
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 is expressed from germinal vesicle (GV) to metaphase II (MII) stages of porcine oocytes and dramatically decreases with the 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 (GVBD). Depletion of Gwl inhibits or delays meiotic maturation secondary to defects in chromosome congression and spindle formation. Conversely, overexpression of Gwl overcame meiotic arrest and initiated progression to the 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.