| Identifier | 04914 | Description | Xenopus oocytes are naturally arrested at G2 of meiosis I Exposure to either insulin/IGF-1 or the steroid hormone progesterone breaks this arrest and induces resumption of the two meiotic division cycles and maturation of the oocyte into a mature, fertilizable egg This process is termed oocyte maturation The transition is accompanied by an increase in maturation promoting factor MPF or Cdc2/cyclin B which precedes germinal vesicle breakdown GVBD Most reports point towards the Mos-MEK1-ERK2 pathway [where ERK is an extracellular signal-related protein kinase, MEK is a MAPK/ERK kinase and Mos is a p42MAPK activator] and the polo-like kinase/CDC25 pathway as responsible for the activation of MPF in meiosis, most likely triggered by a decrease in cAMP |
