Yew N, Mellini M L, Vande Woude G F
ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201.
Nature. 1992 Feb 13;355(6361):649-52. doi: 10.1038/355649a0.
When fully grown Xenopus oocytes are stimulated by progesterone, a period of protein synthesis is necessary for maturation. Synthesis of the mos proto-oncogene product, pp39mos, is necessary for the activation of M-phase promoting factor (MPF) in meiosis I. On the basis that mos is translated de novo on hormonal stimulation of Xenopus oocytes and that injecting mos RNA into oocytes induces their maturation, we have proposed that the mos protein is a candidate initiator of oocyte maturation, needed to trigger the conversion of precursor MPF into its active form. To determine whether mos is the only protein required for initiating maturation, we have produced a soluble, active recombinant mos protein and injected it into Xenopus oocytes. We report here that in the absence of protein synthesis that mos protein efficiently induces germinal vesicle breakdown and the activation of MPF. The oocytes, however, do not proceed into meiosis II. Thus, the mos protein fulfills the requirements of an initiator protein, but the synthesis of one or more additional proteins may be necessary to complete oocyte maturation.
当成熟的非洲爪蟾卵母细胞受到孕酮刺激时，蛋白质合成阶段对于其成熟是必需的。原癌基因mos产物pp39mos的合成对于减数分裂I中M期促进因子（MPF）的激活是必需的。基于在激素刺激非洲爪蟾卵母细胞时mos从头开始翻译，以及将mos RNA注射到卵母细胞中可诱导其成熟这一事实，我们提出mos蛋白是卵母细胞成熟的候选启动因子，它是将前体MPF转化为其活性形式所必需的。为了确定mos是否是启动成熟所需的唯一蛋白质，我们制备了一种可溶性的、有活性的重组mos蛋白，并将其注射到非洲爪蟾卵母细胞中。我们在此报告，在没有蛋白质合成的情况下，mos蛋白能有效地诱导生发泡破裂和MPF的激活。然而，卵母细胞不会进入减数分裂II。因此，mos蛋白满足启动蛋白的要求，但可能需要合成一种或多种其他蛋白质才能完成卵母细胞的成熟。
