From the Department of Radiation Oncology and the Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322.
J Biol Chem. 2014 Mar 14;289(11):7425-37. doi: 10.1074/jbc.M113.520783. Epub 2014 Jan 23.
RNA polymerase II (Pol II) promoter-proximal pausing plays a critical role in postinitiation transcriptional regulation at many metazoan genes. We showed recently that histone H4 lysine 16 acetylation (H4K16Ac), mediated by the MSL complex, facilitates the release of paused Pol II. In contrast, H4 lysine 20 trimethylation (H4K20me3), mediated by SUV420H2, enforces Pol II pausing by inhibiting MSL recruitment. However, how the balance between H4K16Ac and H4K20me3 is locally regulated remains unclear. Here, we demonstrate that PR-SET7/SETD8, which monomethylates histone H4 lysine 20 (H4K20me1), controls both H4K16Ac and H4K20me3 and in doing so, regulates Pol II pausing dynamics. We find that PR-SET7-mediated H4K20me1 is necessary for the recruitment of the MSL complex, subsequent H4K16Ac, and release of Pol II into active elongation. Although dispensable for SUV420H2 recruitment, PR-SET7-mediated H4K20me1 is required for H4K20me3. Although depletion of SUV420H2 is sufficient to deplete H4K20me3 and relieve an H4K20me3-induced pause, pausing is maintained in the absence of PR-SET7 despite H4K20me3 depletion because of an inability to recruit the MSL complex in the absence of H4K20me1. These findings highlight the requirement for PR-SET7 and H4K20me1 in establishing both the H4K16Ac and H4K20me3 marks and point to a dual role in the local regulation of Pol II pausing.
RNA 聚合酶 II（Pol II）启动子近端暂停在许多后生动物基因的起始后转录调控中起着关键作用。我们最近表明，组蛋白 H4 赖氨酸 16 乙酰化（H4K16Ac），由 MSL 复合物介导，促进暂停的 Pol II 的释放。相比之下，组蛋白 H4 赖氨酸 20 三甲基化（H4K20me3），由 SUV420H2 介导，通过抑制 MSL 募集来强制 Pol II 暂停。然而，H4K16Ac 和 H4K20me3 之间的平衡如何在局部得到调节尚不清楚。在这里，我们证明 PR-SET7/SETD8 可以单甲基化组蛋白 H4 赖氨酸 20（H4K20me1），它控制 H4K16Ac 和 H4K20me3，从而调节 Pol II 暂停动力学。我们发现 PR-SET7 介导的 H4K20me1 对于 MSL 复合物的募集、随后的 H4K16Ac 以及 Pol II 进入活跃伸长的释放是必要的。尽管 PR-SET7 介导的 H4K20me1 对于 SUV420H2 的募集不是必需的，但它对于 H4K20me3 是必需的。尽管 SUV420H2 的耗竭足以耗尽 H4K20me3 并缓解 H4K20me3 诱导的暂停，但由于缺乏 H4K20me1 而无法募集 MSL 复合物，因此尽管 H4K20me3 耗尽，暂停仍得以维持。这些发现强调了 PR-SET7 和 H4K20me1 在建立 H4K16Ac 和 H4K20me3 标记方面的必要性，并指出了它们在 Pol II 暂停的局部调节中的双重作用。
