Chromatin structure: does the 30-nm fibre exist in vivo?
Chromatin structure: does the 30-nm fibre exist in vivo?
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DOI：
10.1016/j.ceb.2010.03.001
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发表时间：
2010-06-01
影响因子：
7.5
通讯作者：
Eltsov, Mikhail
中科院分区：
文献类型：
--
作者：
Maeshima, Kazuhiro;Hihara, Saera;Eltsov, Mikhail
一条长链的DNA包裹在核心组蛋白周围，形成一个核小体。尽管长期以来，人们一直认为核小体被折叠成30纳米的染色质纤维，但它们的结构细节以及这些纤维是如何组织成核或有丝分裂染色体的仍不清楚。当我们使用冷冻电子显微镜观察冷冻的水化(玻璃化)人有丝分裂细胞时，我们没有发现包括30 nm染色质纤维在内的更高级别的结构，这使得我们能够在接近自然状态的细胞结构中直接进行高分辨率成像。因此，我们提出，核小体纤维以高度无序、交错的状态存在，就像经历动态运动的聚合物熔体一样。我们假设在活跃的间期核中存在类似的状态，从而在转录和DNA复制过程中产生了几个优点。
A long strand of DNA is wrapped around the core histone and forms a nucleosome. Although the nucleosome has long been assumed to be folded into 30-nm chromatin fibres, their structural details and how such fibres are organised into a nucleus or mitotic chromosome remain unclear. When we observed frozen hydrated (vitrified) human mitotic cells using cryo-electron microscopy, which enables direct high-resolution imaging of the cellular structures in a close-to-native state, we found no higher order structures including 30-nm chromatin fibres in the chromosome. Therefore, we propose that the nucleosome fibres exist in a highly disordered, interdigitated state like a 'polymer melt' that undergoes dynamic movement. We postulate that a similar state exists in active interphase nuclei, resulting in several advantages in the transcription and DNA replication processes.