Stepwise nucleosome translocation by RSC remodeling complexes
Stepwise nucleosome translocation by RSC remodeling complexes
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DOI：
10.7554/elife.10051
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发表时间：
2016-02-19
期刊：
影响因子：
7.7
通讯作者：
Zhuang, Xiaowei
中科院分区：
文献类型：
--
作者：
Harada, Bryan T.;Hwang, William L.;Zhuang, Xiaowei
SWI/ snf家族重塑子通过将ATP水解产生的自由能与核小体的重新定位和重组相结合来调节染色质结构，但这些酶的ATP酶活性如何驱动DNA在核小体中的运动尚不清楚。在这里，我们使用单分子FRET来监测酵母SWI/SNF重塑剂RSC对单核小体的重塑。我们观察到，RSC主要在核小体周围易位DNA，而没有实质性的H2A-H2B二聚体移位。在DNA进入和离开核小体的位置，DNA主要沿着或靠近其规范的包裹路径移动。DNA的易位是逐步发生的，在DNA进入和离开核小体的两个位点上，步长分布在大约1- 2bp处出现峰值。这些结果表明，DNA在核小体上的移动可能与核小体内atp酶结合位点的DNA易位直接相关。
The SWI/SNF-family remodelers regulate chromatin structure by coupling the free energy from ATP hydrolysis to the repositioning and restructuring of nucleosomes, but how the ATPase activity of these enzymes drives the motion of DNA across the nucleosome remains unclear. Here, we used single-molecule FRET to monitor the remodeling of mononucleosomes by the yeast SWI/SNF remodeler, RSC. We observed that RSC primarily translocates DNA around the nucleosome without substantial displacement of the H2A-H2B dimer. At the sites where DNA enters and exits the nucleosome, the DNA moves largely along or near its canonical wrapping path. The translocation of DNA occurs in a stepwise manner, and at both sites where DNA enters and exits the nucleosome, the step size distributions exhibit a peak at approximately 1-2 bp. These results suggest that the movement of DNA across the nucleosome is likely coupled directly to DNA translocation by the ATPase at its binding site inside the nucleosome.