DIFFERENTIAL REGULATION OF E2F TRANSACTIVATION BY CYCLIN CDK2 COMPLEXES
DIFFERENTIAL REGULATION OF E2F TRANSACTIVATION BY CYCLIN CDK2 COMPLEXES
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DOI：
10.1101/gad.8.15.1772
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发表时间：
1994-08-01
影响因子：
10.5
通讯作者：
HARLOW, E
中科院分区：
文献类型：
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作者：
DYNLACHT, BD;FLORES, O;HARLOW, E
哺乳动物转录因子E2 F在细胞增殖所需基因的表达中起关键作用。为了了解E2 F是如何调节的，我们开发了一种重建的体外转录测定。使用这种E2 F-响应测定，我们可以证明E2 F-介导的转录可以直接抑制肿瘤抑制蛋白pRB。这种抑制作用被pRB与细胞周期蛋白A/cdk 2或细胞周期蛋白E/cdk 2的磷酸化所消除。然而，这些细胞周期蛋白/激酶复合物在磷酸化E2 F的能力上表现出差异。只有细胞周期蛋白A/cdk 2可以有效地磷酸化E2 F，这种磷酸化消除了其结合DNA和介导反式激活的能力。因此，这种体外转录测定允许激活和失活的E2 F转录，我们的研究结果表明如何E2 F的转录调控可以连接到细胞周期依赖性激活激酶。
The mammalian transcription factor E2F plays a critical role in the expression of genes required for cellular proliferation. To understand how E2F is regulated, we have developed a reconstituted in vitro transcription assay. Using this E2F-responsive assay, we can demonstrate that E2F-mediated transcription can be directly repressed by the tumor suppressor protein pRB. This inhibition is abolished by phosphorylation of pRB with either cyclin A/cdk2 or cyclin E/cdk2. However, these cyclin/kinase complexes exhibit differences in the ability to phosphorylate E2F. Only cyclin A/cdk2 can phosphorylate E2F effectively, and this phosphorylation abolishes its ability to bind DNA and mediate trans-activation. Thus, this in vitro transcriptional assay allows activation and inactivation of E2F transcription, and our findings demonstrate how transcriptional regulation of E2F can be linked to cell cycle-dependent activation of kinases.