Histone acetylation facilitates RNA polymerase II transcription of the Drosophila hsp26 gene in chromatin
Histone acetylation facilitates RNA polymerase II transcription of the Drosophila hsp26 gene in chromatin
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DOI：
10.1093/emboj/17.10.2865
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发表时间：
1998-05-15
期刊：
影响因子：
11.4
通讯作者：
Becker, PB
中科院分区：
文献类型：
--
作者：
Nightingale, KP;Wellinger, RE;Becker, PB
已知许多激活剂可通过蛋白质乙酰化来增加 RNA 聚合酶 (pol) II 的转录。虽然这些乙酰酶的生理底物尚不清楚，但可能的靶标包括一般转录因子、激活蛋白和组蛋白。使用无细胞系统重建组蛋白乙酰化水平增加的染色质，我们直接测试了组蛋白乙酰化在 RNA pol II 转录中的因果作用。含有对照或乙酰化组蛋白的染色质被重构为可比较的核小体密度，并在补骨脂素交联后通过电子显微镜以及体外转录进行表征。虽然含有 HI 的对照染色质严重抑制了我们模型 hsp26 基因的转录，但高度乙酰化的染色质的抑制作用明显减弱。组蛋白的乙酰化，特别是组蛋白 H4 的乙酰化，影响起始水平的转录。通过监测转录机制与染色质启动子关联的能力，我们发现热休克因子（热休克基因转录的关键调节因子）从组蛋白乙酰化中获益最多。这些实验证明组蛋白乙酰化可以调节激活剂进入染色质中的靶位点，并提供组蛋白乙酰化与染色质中 RNA pol II 转录起始增强之间的因果关系。
A number of activators are known to increase transcription by RNA polymerase (pol) II through protein acetylation. While the physiological substrates for those acetylases are poorly defined, possible targets include general transcription factors, activator proteins and histones. Using a cell-free system to reconstitute chromatin with increased histone acetylation levels, we directly tested for a causal role of histone acetylation in transcription by RNA pol II. Chromatin, containing either control or acetylated histones, was reconstituted to comparable nucleosome densities and characterized by electron microscopy after psoralen cross-linking as well as by in vitro transcription. While HI-containing control chromatin severely repressed transcription of our model hsp26 gene, highly acetylated chromatin was significantly less repressive, Acetylation of histones, and particularly of histone H4, affected transcription at the level of initiation. Monitoring the ability of the transcription machinery to associate with the promoter in chromatin, we found that heat shock factor, a crucial regulator of heat shock gene transcription, profited most from histone acetylation. These experiments demonstrate that histone acetylation can modulate activator access to their target sites in chromatin, and provide a causal link between histone acetylation and enhanced transcription initiation of RNA pol II in chromatin.