DNA translocation and loop formation mechanism of chromatin remodeling by SWI/SNF and RSC
DNA translocation and loop formation mechanism of chromatin remodeling by SWI/SNF and RSC
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DOI：
10.1016/j.molcel.2006.10.025
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发表时间：
2006-11-17
期刊：
影响因子：
16
通讯作者：
Bustamantel, Carlos
中科院分区：
文献类型：
--
作者：
Zhang, Yongli;Smith, Corey L.;Bustamantel, Carlos
ATP依赖性染色质重塑复合物（重塑物）通过调节高度包装的基因组DNA的可及性来调节基因转录。然而，在核小体水平上参与这一过程的分子机制仍然存在争议。在这里，我们监测实时活动的单一ySWI/SNF或RSC复合物上的单一，拉伸核小体模板下的张力超过1 pN的力量。我们发现，这些重塑可以沿着沿着DNA以类似于13 bp/s的速率移位，并产生高达类似于12 pN的力，以核小体依赖的方式产生宽范围大小（20-1200 bp，平均类似于100 bp）的DNA环。这种核小体特异性活性与低张力下观察到的裸DNA显着不同，表明通过核小体内DNA环形成的核小体重塑机制。这种环的形成可以为重塑物的生物学功能提供分子基础。
ATP-dependent chromatin-remodeling complexes (remodelers) modulate gene transcription by regulating the accessibility of highly packaged genomic DNA. However, the molecular mechanisms involved at the nucleosomal level in this process remain controversial. Here, we monitor the real-time activity of single ySWI/SNF or RSC complexes on single, stretched nucleosomal templates under tensions above 1 pN forces. We find that these remodelers can translocate along DNA at rates of similar to 13 bp/s and generate forces up to similar to 12 pN, producing DNA loops of a broad range of sizes (20-1200 bp, average similar to 100 bp) in a nucleosome-dependent manner. This nucleosome-specific activity differs significantly from that on bare DNA observed under low tensions and suggests a nucleosome-remodeling mechanism through intranucleosomal DNA loop formation. Such loop formation may provide a molecular basis for the biological functions of remodelers.