Gross S D, Schwab M S, Lewellyn A L, Maller J L
Howard Hughes Medical Institute and Department of Pharmacology, University of Colorado School of Medicine, Denver, CO 80262, USA.
Science. 1999 Nov 12;286(5443):1365-7. doi: 10.1126/science.286.5443.1365.
Before fertilization, vertebrate eggs are arrested in metaphase of meiosis II by cytostatic factor (CSF), an activity that requires activation of the mitogen-activated protein kinase (MAPK) pathway. To investigate whether CSF arrest is mediated by the protein kinase p90Rsk, which is phosphorylated and activated by MAPK, a constitutively activated (CA) form of Rsk was expressed in Xenopus embryos. Expression of CA Rsk resulted in cleavage arrest, and cytological analysis showed that arrested blastomeres were in M phase with prominent spindles characteristic of meiotic metaphase. Thus, Rsk appears to be the mediator of MAPK-dependent CSF arrest in vertebrate unfertilized eggs.
在受精前，脊椎动物的卵子被细胞静止因子（CSF）阻滞于减数分裂II中期，CSF这种活性需要丝裂原活化蛋白激酶（MAPK）信号通路的激活。为了研究CSF阻滞是否由被MAPK磷酸化并激活的蛋白激酶p90Rsk介导，一种组成型激活（CA）形式的Rsk在非洲爪蟾胚胎中表达。CA Rsk的表达导致卵裂阻滞，细胞学分析表明，被阻滞的卵裂球处于M期，具有减数分裂中期特有的明显纺锤体。因此，Rsk似乎是脊椎动物未受精卵中MAPK依赖的CSF阻滞的介导因子。
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