RELOCATION AND DISTINCT SUBCELLULAR-LOCALIZATION OF P34CDC2-CYCLIN-B COMPLEX AT MEIOSIS REINITIATION IN STARFISH OOCYTES
RELOCATION AND DISTINCT SUBCELLULAR-LOCALIZATION OF P34CDC2-CYCLIN-B COMPLEX AT MEIOSIS REINITIATION IN STARFISH OOCYTES
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DOI：
10.1002/j.1460-2075.1992.tb05228.x
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发表时间：
1992-05-01
期刊：
影响因子：
11.4
通讯作者：
KISHIMOTO, T
中科院分区：
文献类型：
--
作者：
OOKATA, K;HISANAGA, S;KISHIMOTO, T
M期促进因子（MPF）是真核细胞进入M期的主要调控因子。MPF由两个亚基p34 cdc 2和cyclin B组成。利用抗海星细胞周期蛋白B的特异性抗体进行间接免疫荧光染色，我们监测了海星卵母细胞减数分裂再启动过程中MPF的亚细胞分布动态。我们发现，所有的细胞周期蛋白B已经与p34 cdc 2在未成熟的卵母细胞停滞在G2/M边界，这种非活性的复合物是目前专门在细胞质中。在其激活后，部分p34 cdc 2-细胞周期蛋白B复合物在核膜破裂前进入生发囊泡，独立于微管或肌动蛋白丝。此后，复合体的一部分聚集在核仁和浓缩的染色体中。复合体的另一部分积累在减数分裂的紫苑和纺锤体上，而其余部分仍然存在于整个细胞质中。由于这些模式的本地化检测在洗涤剂提取的卵母细胞，我们提出了至少四个不同的亚细胞状态的p34 cdc 2-细胞周期蛋白B复合物：自由可溶性，微管相关，洗涤剂抗性cytokeron-associated和染色体相关。因此，除了p34 cdc 2-cyclin B复合物的分子内修饰外，其细胞内重新定位在促进M期中起关键作用。
M phase promoting factor (MPF) is a major element controlling entry into the M phase of the eukaryotic cell cycle. MPF is composed of two subunits, p34cdc2 and cyclin B. Using indirect immunofluorescence staining with specific antibody against starfish cyclin B, we monitored the dynamics of the subcellular distribution of MPF during meiosis reinitiation in starfish oocytes. We found that all of the cyclin B is already associated with p34cdc2 in immature oocytes arrested at the G2/M border and that this inactive complex is present exclusively in the cytoplasm. After its activation, part of the p34cdc2-cyclin B complex moves into the germinal vesicle before nuclear envelope breakdown, independently of either microtubules or actin filaments. Thereafter, some part of the complex accumulates in the nucleolus and condensed chromosomes. Another portion of the complex accumulates on meiotic asters and spindles, while the rest is still present throughout the cytoplasm. As these patterns of localization are detected in the detergent-extracted oocytes, we propose at least four distinct subcellular states of the p34cdc2-cyclin B complex: freely soluble, microtubule-associated, detergent-resistant cytoskeleton-associated and chromosome-associated. Thus, in addition to the intramolecular modification of p34cdc2-cyclin B complex, its intracellular relocation plays a key role in promoting the M phase.