New B-type cyclin synthesis is required between meiosis I and II during Xenopus oocyte maturation.
New B-type cyclin synthesis is required between meiosis I and II during Xenopus oocyte maturation.
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发表时间：
2001-10
期刊：
影响因子：
4.6
通讯作者：
H. Hochegger;A. Klotzbücher;J. Kirk;M. Howell;K. Le Guellec;K. Fletcher;T. Duncan;Muhammad Sohail;T. Hunt
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作者：
H. Hochegger;A. Klotzbücher;J. Kirk;M. Howell;K. Le Guellec;K. Fletcher;T. Duncan;Muhammad Sohail;T. Hunt
通过减数分裂的进展需要两波成熟促进因子（MPF）活性，对应于减数分裂I和减数分裂II。青蛙卵母细胞含有一个池的无活性的“前MPF”的细胞周期蛋白依赖性激酶1结合B型细胞周期蛋白，其中我们现在发现三个以前未被怀疑的成员，细胞周期蛋白B3，B4和B5。蛋白质的合成需要激活前MPF，我们在这里表明，这并不需要新的B型细胞周期蛋白的合成，可能是因为一个大的母亲库存的细胞周期蛋白B2和B5。这种储备在减数分裂I后降解，因此，减数分裂II的MPF激活需要新的细胞周期蛋白合成，主要是细胞周期蛋白B1和B4，其翻译在减数分裂I后被强烈激活。如果这波新的细胞周期蛋白合成被反义寡核苷酸阻断，卵母细胞就会退化，不能形成第二个减数分裂纺锤体。当减数分裂I后添加放线菌酮阻断所有新蛋白质合成时，对减数分裂进程的影响甚至更严重，但可以通过注射不可破坏的B型细胞周期蛋白来挽救。B型细胞周期蛋白和MPF活性是维持减数分裂II期间c-mos和MAP激酶活性以及在减数分裂成熟结束时建立中期阻滞所必需的。我们讨论了c-mos和MPF的相互依赖性，并揭示了两个减数分裂分裂之间的细胞周期蛋白合成的翻译控制的重要作用。
Progression through meiosis requires two waves of maturation promoting factor (MPF) activity corresponding to meiosis I and meiosis II. Frog oocytes contain a pool of inactive "pre-MPF" consisting of cyclin-dependent kinase 1 bound to B-type cyclins, of which we now find three previously unsuspected members, cyclins B3, B4 and B5. Protein synthesis is required to activate pre-MPF, and we show here that this does not require new B-type cyclin synthesis, probably because of a large maternal stockpile of cyclins B2 and B5. This stockpile is degraded after meiosis I and consequently, the activation of MPF for meiosis II requires new cyclin synthesis, principally of cyclins B1 and B4, whose translation is strongly activated after meiosis I. If this wave of new cyclin synthesis is ablated by antisense oligonucleotides, the oocytes degenerate and fail to form a second meiotic spindle. The effects on meiotic progression are even more severe when all new protein synthesis is blocked by cycloheximide added after meiosis I, but can be rescued by injection of indestructible B-type cyclins. B-type cyclins and MPF activity are required to maintain c-mos and MAP kinase activity during meiosis II, and to establish the metaphase arrest at the end of meiotic maturation. We discuss the interdependence of c-mos and MPF, and reveal an important role for translational control of cyclin synthesis between the two meiotic divisions.