CNRS, Laboratoire de Spectrometrie Physique, St Martin d'Heres, France.
FEBS J. 2011 Jul;278(13):2231-43. doi: 10.1111/j.1742-4658.2011.08153.x. Epub 2011 May 26.
About a decade ago, the elastic properties of a single chromatin fiber and, subsequently, those of a single nucleosome started to be explored using optical and magnetic tweezers. These techniques have allowed direct measurements of several essential physical parameters of individual nucleosomes and nucleosomal arrays, including the forces responsible for the maintenance of the structure of both the chromatin fiber and the individual nucleosomes, as well as the mechanism of their unwinding under mechanical stress. Experiments on the assembly of individual chromatin fibers have illustrated the complexity of the process and the key role of certain specific components. Nevertheless a substantial disparity exists in the data reported from various experiments. Chromatin, unlike naked DNA, is a system which is extremely sensitive to environmental conditions, and studies carried out under even slightly different conditions are difficult to compare directly. In this review we summarize the available data and their impact on our knowledge of both nucleosomal structure and the dynamics of nucleosome and chromatin fiber assembly and organization.
大约十年前，人们开始使用光学和磁镊研究单个染色质纤维的弹性特性，随后又研究了单个核小体的弹性特性。这些技术使人们能够直接测量单个核小体和核小体阵列的几个基本物理参数，包括维持染色质纤维和单个核小体结构的力，以及在机械应力下解开它们的机制。关于单个染色质纤维组装的实验说明了该过程的复杂性以及某些特定成分的关键作用。然而，不同实验报告的数据存在很大差异。与裸露的 DNA 不同，染色质是一个对环境条件极其敏感的系统，即使在稍微不同的条件下进行的研究也很难直接进行比较。在这篇综述中，我们总结了现有的数据及其对我们了解核小体结构以及核小体和染色质纤维组装和组织的动力学的影响。
