Cyclin-Dependent Kinase 7 Controls mRNA Synthesis by Affecting Stability of Preinitiation Complexes, Leading to Altered Gene Expression, Cell Cycle Progression, and Survival of Tumor Cells
Cyclin-Dependent Kinase 7 Controls mRNA Synthesis by Affecting Stability of Preinitiation Complexes, Leading to Altered Gene Expression, Cell Cycle Progression, and Survival of Tumor Cells
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DOI：
10.1128/mcb.00595-14
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发表时间：
2014-10-01
影响因子：
5.3
通讯作者：
Meisterernst, Michael
中科院分区：
文献类型：
--
作者：
Kelso, Timothy W. R.;Baumgart, Karen;Meisterernst, Michael
细胞周期蛋白依赖性激酶7（CDK 7）激活细胞周期CDKs，是一般转录因子TFIIH的成员。虽然有大量证据表明CDK 7在mRNA合成和相关过程中发挥积极作用，但其对哺乳动物物种中全局和基因特异性转录的影响程度尚不清楚。在目前的研究中，我们利用两种对CDK 7具有高特异性的新型抑制剂来证明CDK 7对体内和体外重建反应中基因转录的有限但强大的影响。我们区分相对低剂量和高剂量的反应，并将它们与不同的分子机制和改变的生理反应。低剂量的抑制剂会导致暂停的RNA聚合酶II（RNAPII）分子的快速清除，并足以导致基因表达的全基因组改变，G（1）/S和G（2）/M检查点的细胞周期进展延迟，以及人类肿瘤细胞的存活减少。更高的剂量和延长的抑制导致RNAPII羧基末端结构域（CTD）磷酸化的强烈减少，最终激活p53程序，并增加细胞死亡。总之，我们的数据解释了CDK 7对mRNA合成的定量贡献，这对细胞稳态至关重要。
Cyclin-dependent kinase 7 (CDK7) activates cell cycle CDKs and is a member of the general transcription factor TFIIH. Although there is substantial evidence for an active role of CDK7 in mRNA synthesis and associated processes, the degree of its influence on global and gene-specific transcription in mammalian species is unclear. In the current study, we utilize two novel inhibitors with high specificity for CDK7 to demonstrate a restricted but robust impact of CDK7 on gene transcription in vivo and in in vitro-reconstituted reactions. We distinguish between relative low- and high-dose responses and relate them to distinct molecular mechanisms and altered physiological responses. Low inhibitor doses cause rapid clearance of paused RNA polymerase II (RNAPII) molecules and sufficed to cause genome-wide alterations in gene expression, delays in cell cycle progression at both the G(1)/S and G(2)/M checkpoints, and diminished survival of human tumor cells. Higher doses and prolonged inhibition led to strong reductions in RNAPII carboxyl-terminal domain (CTD) phosphorylation, eventual activation of the p53 program, and increased cell death. Together, our data reason for a quantitative contribution of CDK7 to mRNA synthesis, which is critical for cellular homeostasis.