Cooperative activity of BRG1 and Z-DNA formation in chromatin remodeling
Cooperative activity of BRG1 and Z-DNA formation in chromatin remodeling
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DOI：
10.1128/mcb.26.7.2550-2559.2006
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发表时间：
2006-04-01
影响因子：
5.3
通讯作者：
Zhao, K
中科院分区：
文献类型：
--
作者：
Liu, H;Mulholland, N;Zhao, K
哺乳动物基因组中含有成千上万的CG和TG重复序列，这些重复序列具有形成非经典左手双螺旋Z-DNA结构的高潜力。以前，我们表明，激活的集落刺激因子1（CSF 1）基因的染色质重塑酶，BRG 1，在位于启动子内的TG重复序列的Z-DNA的形成的结果。在这份报告中，我们表明，TG重复组装在一个定位的核小体在沉默的CSF 1启动子和激活BRG 1破坏这个核小体，并导致Z-DNA的形成。活性转录不是形成Z-DNA所必需的，但确实会导致Z-DNA的扩展区域。BRG 1和Z-DNA序列的形成是CSF 1启动子有效染色质重塑所必需的。我们提出由BRG 1诱导的Z-DNA形成促进了从瞬时和部分重塑到更广泛破坏典型核小体结构的转变。本报告中提供的数据表明，Z-DNA的形成是调节染色质结构的重要机制，与ATP依赖性重塑和翻译后组蛋白修饰的活性相似。
The mammalian genome contains tens of thousands of CG and TG repeat sequences that have high potential to form the nonclassical left-handed double-helical Z-DNA structure. Previously we showed that activation of the colony-stimulating factor 1 (CSF1) gene by the chromatin remodeling enzyme, BRG1, results in formation of Z-DNA at the TG repeat sequence located within the promoter. In this report, we show that the TG repeats are assembled in a positioned nucleosome in the silent CSF1 promoter and that activation by BRG1 disrupts this nucleosome and results in Z-DNA formation. Active transcription is not required for the formation of Z-DNA but does result in an expanded region of Z-DNA. Formation of sequences by both BRG1 and the Z-DNA is required for effective chromatin remodeling of the CSF1 promoter. We propose the Z-DNA formation induced by BRG1 promotes a transition from a transient and partial remodeling to a more extensive disruption of the canonical nucleosomal structure. The data presented in this report establish that Z-DNA formation is an important mechanism in modulating chromatin structure, in similarity to the activities of ATP-dependent remodelers and posttranslational histone modifications.