Mitotic chromosome structure: reproducibility of folding and symmetry between sister chromatids.
Mitotic chromosome structure: reproducibility of folding and symmetry between sister chromatids.
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有丝分裂染色体结构：姐妹染色单体之间折叠和对称性的再现性。
DOI：
10.1016/j.bpj.2008.10.051
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发表时间：
2009
影响因子：
3.4
通讯作者：
Belmont,AS
中科院分区：
文献类型：
--
作者：
Strukov,YuriG;Belmont,AS
有丝分裂的染色体结构和有丝分裂凝聚的途径尚不清楚。有丝分裂染色体结构的结构数据有限，无法区分几种相互冲突的模型。在这里，我们使用了一个中国仓鼠卵巢细胞系，该细胞系具有分布在∼1μm染色体臂区域的三个不同的带有乳糖操作者标记的载体插入，以确定定位的重复性、大规模染色质折叠中的长程相关性以及最小扰动的中期染色体中的姐妹染色单体对称性。在分离的中期染色体上，用Lacreposer染色的标记点的三维位置相对于标记了拓扑异构酶II抗体的中央染色单体轴进行了测量。点的纵向定位是可重现的，但在姐妹染色单体之间表现出内在的变异，最大可达∼300 nm。同一染色单体上的斑点位置是不相关的，姐妹染色单体上相应斑点的位置之间也没有相关性或对称性，这表明在数十个百万碱基上缺乏高度有序的长程染色质折叠。我们的观察结果与没有任何规则的、可重复的螺旋末级染色体折叠是一致的，但与任何分级折叠模型保持一致，在该模型中，折叠中的不规则性存在于一个或多个水平。
Mitotic chromosome structure and pathways of mitotic condensation remain unknown. The limited amount of structural data on mitotic chromosome structure makes it impossible to distinguish between several mutually conflicting models. Here we used a Chinese hamster ovary cell line with three differentlacoperator-tagged vector insertions distributed over an ∼1μm chromosome arm region to determine positioning reproducibility, long-range correlation in large-scale chromatin folding, and sister chromatid symmetry in minimally perturbed, metaphase chromosomes. The three-dimensional positions of theselacoperator-tagged spots, stained withlacrepressor, were measured in isolated metaphase chromosomes relative to the central chromatid axes labeled with antibodies to topoisomerase II. Longitudinal, but not axial, positioning of spots was reproducible but showed intrinsic variability, up to ∼300 nm, between sister chromatids. Spot positions on the same chromatid were uncorrelated, and no correlation or symmetry between the positions of corresponding spots on sister chromatids was detectable, showing the absence of highly ordered, long-range chromatin folding over tens of mega-basepairs. Our observations are in agreement with the absence of any regular, reproducible helical, last level of chromosome folding, but remain consistent with any hierarchical folding model in which irregularity in folding exists at one or multiple levels.