Department of Molecular Biology and Genetics, Cornell University, 107 Biotechnology Building, 526 Campus Road, Ithaca, NY, 14853-2703, USA.
Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
Nat Commun. 2018 Feb 7;9(1):543. doi: 10.1038/s41467-018-03006-4.
Post-translational modifications of the transcription elongation complex provide mechanisms to fine-tune gene expression, yet their specific impacts on RNA polymerase II regulation remain difficult to ascertain. Here, in Schizosaccharomyces pombe, we examine the role of Cdk9, and related Mcs6/Cdk7 and Lsk1/Cdk12 kinases, on transcription at base-pair resolution with Precision Run-On sequencing (PRO-seq). Within a minute of Cdk9 inhibition, phosphorylation of Pol II-associated factor, Spt5 is undetectable. The effects of Cdk9 inhibition are more severe than inhibition of Cdk7 and Cdk12, resulting in a shift of Pol II toward the transcription start site (TSS). A time course of Cdk9 inhibition reveals that early transcribing Pol II can escape promoter-proximal regions, but with a severely reduced elongation rate of only ~400 bp/min. Our results in fission yeast suggest the existence of a conserved global regulatory checkpoint that requires Cdk9 kinase activity.
转录延伸复合物的翻译后修饰提供了精细调节基因表达的机制，但它们对 RNA 聚合酶 II 调节的确切影响仍难以确定。在这里，我们在裂殖酵母中检查了 Cdk9 以及相关的 Mcs6/Cdk7 和 Lsk1/Cdk12 激酶在碱基对分辨率上对转录的作用，使用了精确运行序列（PRO-seq）。在 Cdk9 抑制后一分钟内，与 Pol II 相关的因子 Spt5 的磷酸化检测不到。Cdk9 抑制的影响比 Cdk7 和 Cdk12 的抑制更为严重，导致 Pol II 向转录起始位点（TSS）移动。Cdk9 抑制的时程显示，早期转录的 Pol II 可以逃避启动子近端区域，但延伸率严重降低，仅为~400 bp/min。我们在裂殖酵母中的研究结果表明，存在一个保守的全局调控检查点，需要 Cdk9 激酶活性。
