Structure of mitotic chromosomes.
Structure of mitotic chromosomes.
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DOI：
10.1016/j.molcel.2021.08.020
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发表时间：
2021-11-04
期刊：
影响因子：
16
通讯作者：
Kornberg RD
中科院分区：
文献类型：
--
作者：
Beel AJ;Azubel M;Matteï PJ;Kornberg RD
染色质纤维在染色体凝聚过程中必须折叠或卷曲。重组染色质的卷曲模式已经被证明，但由于材料的高密度，无法直观地看到染色体浓缩状态下纤维的实际轨迹。我们利用有丝分裂染色体的部分解聚，通过冷冻电子断层扫描，在亚核小体分辨率下揭示了它们的内部结构，而不需要使用染色、固定剂、研磨或切片。可以看到围绕核小体的DNA回旋，从而可以识别核小体并确定它们的方向。连接DNA区域被追踪，揭示了染色质纤维的轨迹。这些轨迹是不规则的，几乎没有卷曲的证据，也没有染色体材料的短或长顺序。146个碱基对的核心颗粒长期以来被认为是核酸酶消化的产物，被认为是核小体的天然状态，沿染色质纤维没有规则的间距。有丝分裂染色体的部分解聚和冷冻电子断层扫描揭示了染色体物质的内部结构。核小体和它们之间的连接物DNA片段被观察到，使得染色质纤维可以在10千碱基(50个核小体)或更远的距离上被追踪。现在可以确定特定基因区域的卷曲或折叠模式。
Chromatin fibers must fold or coil in the process of chromosome condensation. Patterns of coiling have been demonstrated for reconstituted chromatin, but the actual trajectories of fibers in condensed states of chromosomes could not be visualized, due to the high density of the material. We have exploited partial decondensation of mitotic chromosomes to reveal their internal structure at sub-nucleosomal resolution by cryo-electron tomography, without the use of stains, fixatives, milling, or sectioning. DNA gyres around nucleosomes were visible, allowing the nucleosomes to be identified and their orientations determined. Linker DNA regions were traced, revealing the trajectories of chromatin fibers. The trajectories were irregular, with virtually no evidence of coiling and no short- or long-range order of the chromosomal material. The 146 base pair core particle, long known as a product of nuclease digestion, is identified as the native state of the nucleosome, with no regular spacing along the chromatin fibers. Partial decondensation of mitotic chromosomes and cryo-electron tomography revealed the internal structure of the chromosomal material. Nucleosomes and linker DNA segments between them were observed, permitting chromatin fibers to be traced over distances of 10 kilobases (50 nucleosomes) or more. Patterns of coiling or folding in specific gene regions can now be determined.
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影响因子：
7.7
作者：
Bykov YS;Schaffer M;Dodonova SO;Albert S;Plitzko JM;Baumeister W;Engel BD;Briggs JA
通讯作者：
Briggs JA
影响因子：
4
作者：
Poirier, MG;Monhait, T;Marko, JF
通讯作者：
Marko, JF
DOI：
10.1073/pnas.0810057105
发表时间：
2008-12-16
影响因子：
11.1
作者：
Eltsov, Mikhail;MacLellan, Kirsty M.;Dubochet, Jacques
通讯作者：
Dubochet, Jacques
影响因子：
3
作者：
Kremer, JR;Mastronarde, DN;McIntosh, JR
通讯作者：
McIntosh, JR
影响因子：
3.3
作者：
Cai S;Böck D;Pilhofer M;Gan L
通讯作者：
Gan L