Abnormal development of mouse embryoid bodies lacking p27Kip1 cell cycle regulator
Abnormal development of mouse embryoid bodies lacking p27Kip1 cell cycle regulator
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DOI：
10.1634/stemcells.2004-0174
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发表时间：
2005-08-01
期刊：
影响因子：
5.2
通讯作者：
Hampl, A
中科院分区：
文献类型：
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作者：
Bryja, V;Cajánek, L;Hampl, A
胚胎干细胞（ESC）的三维聚集体（称为胚状体（EB））的培养物提供了一个有价值的系统，用于分析调节这种独特细胞类型分化的分子机制。细胞周期蛋白依赖性激酶抑制剂p27（Kip1）（p27）在小鼠胚胎干细胞（mESCs）分化过程中升高。在这项研究中，从正常和p27缺陷的胚胎干细胞产生的EB分化的各个方面进行了分析，以解决这种海拔的生物学意义。结果发现，缺乏p27的EB生长显着更大，但这并不伴随着细胞周期蛋白依赖性激酶（CDK）的活动检测异常。在大多数EB细胞中，下调活化的细胞周期蛋白而不是上调抑制p27可能是降低其CDK活性的原因。在p27缺陷的EBB中也观察到特定细胞谱系发育的异常。这些包括细胞角蛋白内-A（TROMA-I）阳性细胞的消除以及源自Lewis-X阳性细胞的增殖和空腔形成增加。我们的数据还表明，虽然两个不同的池的Lewis-X表达细胞，集群形成（ESC样）和空腔形成（神经祖细胞），通常存在于EBB，p27的缺乏导致的增强只有神经池。当使用各种蛋白质标记物测试p27缺陷型mESCs的神经原性能力时，没有发现失败。总之，我们的数据表明p27在mESC中具有双重作用，一个作用是调节增殖，另一个作用是建立分化表型的其他方面。
Cultures of three-dimensional aggregates of embryonic stem cells (ESCs) called embryoid bodies (EBs) provide a valuable system for analyzing molecular mechanisms that regulate differentiation of this unique cell type. Cyclin-dependent kinase inhibitor p27(Kip1) (p27) becomes elevated during the differentiation of mouse ESCs (mESCs). In this study, various aspects of differentiation of EBs produced from normal and p27-deficient mESCs were analyzed to address the biological significance of this elevation. It was found that EBs lacking p27 grew significantly bigger, but this was not accompanied by detectable abnormalities in the activities of cyclin-dependent kinases (CDKs). In most EB cells, downregulation of activating cyclins rather than upregulation of inhibiting p27 is probably responsible for lowering the activity of their CDKs. Abnormalities in the development of specific cell lineages were also observed in p27-deficient EBB. These included elimination of cells positive for cytokeratin endo-A (TROMA-I) and increased proliferation and formation of cavities originating from cells positive for Lewis-X. Our data also suggest that although two different pools of Lewis-X-expressing cells, cluster forming (ESC-like) and cavity forming (neural progenitors), normally exist in EBB, the absence of p27 leads to the enhancement of only the neural pool. No failure was found when the neurogenic capacity of p27-deficient mESCs was tested using various protein markers. Together, our data point to a dual role of p27 in mESCs, with one role being in the regulation of proliferation and the other role in establishing some other aspects of a differentiated phenotype.