Nucleosome hopping and sliding kinetics determined from dynamics of single chromatin fibers in Xenopus egg extracts
Nucleosome hopping and sliding kinetics determined from dynamics of single chromatin fibers in Xenopus egg extracts
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DOI：
10.1073/pnas.0701459104
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发表时间：
2007-08-21
影响因子：
11.1
通讯作者：
Marko, John F.
中科院分区：
文献类型：
--
作者：
Ranjith, Padinhateeri;Yan, Jie;Marko, John F.
Chromatin function in vivo is intimately connected with changes in its structure: a prime example is occlusion or exposure of regulatory sequences via repositioning of nucleosomes.细胞提取物与单 DNA 显微操作配合使用可以在类似体内的条件下控制和监测这些动态。 We analyze a theory of the assembly-disassembly dynamics of chromatin fiber in such experiments, including effects of lateral nucleosome diff fusion ('' sliding '') and sequence positioning.实验数据确定了力依赖性的开启和解离速率以及核小体滑动扩散速率。 The resulting theory simply explains the very different nucleosome displacement kinetics observed in constant-force and constant-pulling velocity experiments. We also show that few-piconewton tensions comparable to I those generated by polymerases and helicases drastically affect nucleosome positions in a sequence-dependent manner and that there is a long-lived structural '' memory '' of force-driven nucleosome rearrangement events.
Chromatin function in vivo is intimately connected with changes in its structure: a prime example is occlusion or exposure of regulatory sequences via repositioning of nucleosomes. Cell extracts used in concert with single-DNA micromanipulation can control and monitor these dynamics under in vivo-like conditions. We analyze a theory of the assembly-disassembly dynamics of chromatin fiber in such experiments, including effects of lateral nucleosome diff fusion ('' sliding '') and sequence positioning. Experimental data determine the force-dependent on- and off-rates as well as the nucleosome sliding diffusion rate. The resulting theory simply explains the very different nucleosome displacement kinetics observed in constant-force and constant-pulling velocity experiments. We also show that few-piconewton tensions comparable to I those generated by polymerases and helicases drastically affect nucleosome positions in a sequence-dependent manner and that there is a long-lived structural '' memory '' of force-driven nucleosome rearrangement events.