一个Cdk9-PP1开关调节RNA聚合酶II的延长终止过渡
Pabitra K Parua1, Gregory T Booth2, Miriam Sansó1,3
1Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Nature
|June 15, 2018
概括
这项研究揭示了蛋白酸酶1 (PP1) 和循环素依赖性激酶9 (Cdk9) 如何调节RNA聚合酶II (Pol II) 转录的终止. 这涉及去化Spt5延长因子,确保适当的基因表达.
科学领域:
- 分子生物学
- 基因调控
- 生物化学
背景情况:
- 通过RNA聚合酶II (Pol II) 终止转录对于基因表达的调节至关重要.
- 启动终结的精确机制,特别是涉及Pol II酸化和延长因子,仍然不完全理解.
- 已知正转录延长因子b (P-TEFb),包括循环素依赖性激酶9 (Cdk9) - 循环素T1 (CycT1),可以调节转录延长.
研究的目的:
- 研究Cdk9和蛋白酸酶1 (PP1) 在调节转录周期结束中的作用.
- 阐明在转录终止期间控制Spt5酸化的机制.
- 了解Cdk9和PP1在Schizosaccharomyces pombe中控制Pol II转录终止的相互作用.
主要方法:
- 化学基因查以确定PP1异型为P-TEFb基质.
- 使用Dis2和Spt5进行体外脱测试.
- 在生物分裂酵母中使用异位突变和Cdk9抑制的体内研究.
- 染色体免疫沉和测序 (ChIP-seq) 用于分析Spt5酸化和Pol II占用.
- 精确运行转录和测序 (PRO-seq) 来评估转录终止.
主要成果:
- 在PP1异形Dis2上,Cdk9可化延长因子Spt5和一个调节位点.
- 在体内,dis2 脱化了Cdk9 化Spt5,而dis2 突变破坏了Spt5 的脱化.
- 当转录复合物通过裂变和多化信号时,Spt5脱发生,与Pol II Ser2化相吻合.
- 禁用Dis2功能导致超出正常终端位的异常转录,并通过Spt5中Cdk9目标位的切除来抑制.
结论:
- 从Pol II延伸到终结的过渡涉及到Cdk9信号的Dis2依赖性反转.
- 这种涉及Spt5脱的调节开关对于正确的转录终止和转录组完整性至关重要.
- 这些发现与涉及Cdk1和PP1的细胞周期控制机制相似.
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