Human cyclins A and B1 are differentially located in the cell and undergo cell cycle-dependent nuclear transport.
Human cyclins A and B1 are differentially located in the cell and undergo cell cycle-dependent nuclear transport.
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DOI：
10.1083/jcb.115.1.1
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发表时间：
1991-10
期刊：
影响因子：
--
通讯作者：
Hunter T
中科院分区：
文献类型：
--
作者：
Pines J;Hunter T
我们使用免疫荧光染色来研究体细胞周期中细胞周期蛋白 A 和 B1 的亚细胞分布。在原代人成纤维细胞和上皮肿瘤细胞中，我们发现细胞周期蛋白 A 从 S 期开始主要位于细胞核中。 Cyclin A可能与前期的浓缩染色体有关，但与中期的浓缩染色体无关。相比之下，细胞周期蛋白 B1 积聚在间期细胞的细胞质中，仅在有丝分裂开始时、核纤层破裂之前进入细胞核。在有丝分裂细胞中，细胞周期蛋白 B1 与前期和中期的浓缩染色体以及有丝分裂装置相关。细胞周期蛋白A在中期被降解，细胞周期蛋白B1在中期-后期转变时被急剧破坏。细胞分级分离和免疫沉淀研究表明，细胞周期蛋白 A 和细胞周期蛋白 B1 均与含有 PSTAIRE 的蛋白质相关。细胞周期蛋白 A 的细胞核形式（而非细胞质形式）与包含 33-kD PSTAIRE 的蛋白质相关。细胞周期蛋白 B1 与细胞质中的 p34cdc2 相关。因此，我们提出细胞周期中细胞周期蛋白 A 和细胞周期蛋白 B1 的不同定位可能是两种类型的有丝分裂细胞周期蛋白赋予其相关的含有 PSTAIRE 的蛋白激酶亚基的底物特异性的方式。
We have used immunofluorescence staining to study the subcellular distribution of cyclin A and B1 during the somatic cell cycle. In both primary human fibroblasts and in epithelial tumor cells, we find that cyclin A is predominantly nuclear from S phase onwards. Cyclin A may associated with condensing chromosomes in prophase, but is not associated with condensed chromosomes in metaphase. By contrast, cyclin B1 accumulates in the cytoplasm of interphase cells and only enters the nucleus at the beginning of mitosis, before nuclear lamina breakdown. In mitotic cells, cyclin B1 associates with condensed chromosomes in prophase and metaphase, and with the mitotic apparatus. Cyclin A is degraded during metaphase and cyclin B1 is precipitously destroyed at the metaphase----anaphase transition. Cell fractionation and immunoprecipitation studies showed that both cyclin A and cyclin B1 are associated with PSTAIRE-containing proteins. The nuclear, but not the cytoplasmic form, of cyclin A is associated with a 33-kD PSTAIRE- containing protein. Cyclin B1 is associated with p34cdc2 in the cytoplasm. Thus we propose that the different localization of cyclin A and cyclin B1 in the cell cycle could be the means by which the two types of mitotic cyclin confer substrate specificity upon their associated PSTAIRE-containing protein kinase subunit.