Bowman Gregory D, McKnight Jeffrey N
T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA.
Institute of Molecular Biology, University of Oregon, Eugene, OR, USA.
Bioessays. 2017 Jan;39(1):1-8. doi: 10.1002/bies.201600183. Epub 2016 Nov 16.
Eukaryotic genomes are functionally organized into chromatin, a compact packaging of nucleoproteins with the basic repeating unit known as the nucleosome. A major focus for the chromatin field has been understanding what rules govern nucleosome positioning throughout the genome, and here we review recent findings using a novel, sequence-targeted remodeling enzyme. Nucleosomes are often packed into evenly spaced arrays that are reproducibly positioned, but how such organization is established and maintained through dramatic events such as DNA replication is poorly understood. We hypothesize that a major fraction of positioned nucleosomes arises from sequence-specific targeting of chromatin remodelers to generate "founding" nucleosomes, providing reproducible, predictable, and condition-specific nucleation sites against which neighboring nucleosomes are packed into evenly spaced arrays.
真核生物基因组在功能上被组织成染色质，这是一种核蛋白的紧密包装形式，其基本重复单元被称为核小体。染色质领域的一个主要研究重点是了解哪些规则支配着整个基因组中核小体的定位，在此我们回顾了使用一种新型的、序列靶向重塑酶的最新研究发现。核小体通常被包装成间距均匀且可重复定位的阵列，但对于通过诸如DNA复制等重大事件如何建立和维持这种组织形式，我们却知之甚少。我们推测，大部分定位的核小体源自染色质重塑因子的序列特异性靶向作用，从而产生“起始”核小体，这些核小体提供了可重复、可预测且特定条件下的成核位点，相邻核小体据此被包装成间距均匀的阵列。
