Chromatin as dynamic 10-nm fibers.
Chromatin as dynamic 10-nm fibers.
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DOI：
10.1007/s00412-014-0460-2
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发表时间：
2014-06
期刊：
影响因子：
1.6
通讯作者：
Nozaki T
中科院分区：
文献类型：
--
作者：
Maeshima K;Imai R;Tamura S;Nozaki T
自从弗莱明在世纪描述了一种核物质并将其命名为“染色质”以来，这种物质一直吸引着生物学家。染色质的结构是什么？DNA包裹在核心组蛋白周围，形成核小体纤维（10纳米纤维）。这种纤维长期以来一直被认为是折叠成一个30纳米的染色质纤维，随后进入螺旋折叠的更大的纤维或径向环。然而，最近的几项研究，包括我们的cryo-EM和X-射线散射分析，表明染色质是由不规则折叠的10-nm的纤维，没有30-nm的染色质纤维，在间期染色质和有丝分裂染色体。这种不规则的折叠意味着染色质状态在物理上受到较少的限制，与经典的规则螺旋折叠结构相比，这可能更具动态性。与此相一致，最近，我们通过单个核小体成像发现了活的哺乳动物细胞中的大核小体波动（约50 nm/30 ms）。随后的计算模型表明，核小体波动增加染色质的可及性，这是有利的许多“目标搜索”的生物过程，如转录调控。因此，这篇综述提供了一个新的观点染色质结构，其中染色质由动态和无序的10纳米纤维。
Since Flemming described a nuclear substance in the nineteenth century and named it “chromatin,” this substance has fascinated biologists. What is the structure of chromatin? DNA is wrapped around core histones, forming a nucleosome fiber (10-nm fiber). This fiber has long been assumed to fold into a 30-nm chromatin fiber and subsequently into helically folded larger fibers or radial loops. However, several recent studies, including our cryo-EM and X-ray scattering analyses, demonstrated that chromatin is composed of irregularly folded 10-nm fibers, without 30-nm chromatin fibers, in interphase chromatin and mitotic chromosomes. This irregular folding implies a chromatin state that is physically less constrained, which could be more dynamic compared with classical regular helical folding structures. Consistent with this, recently, we uncovered by single nucleosome imaging large nucleosome fluctuations in living mammalian cells (∼50 nm/30 ms). Subsequent computational modeling suggested that nucleosome fluctuation increases chromatin accessibility, which is advantageous for many “target searching” biological processes such as transcriptional regulation. Therefore, this review provides a novel view on chromatin structure in which chromatin consists of dynamic and disordered 10-nm fibers.
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影响因子：
7.5
作者：
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通讯作者：
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DOI：
10.1073/pnas.0810057105
发表时间：
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影响因子：
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