A 3-DIMENSIONAL APPROACH TO MITOTIC CHROMOSOME STRUCTURE - EVIDENCE FOR A COMPLEX HIERARCHICAL ORGANIZATION
A 3-DIMENSIONAL APPROACH TO MITOTIC CHROMOSOME STRUCTURE - EVIDENCE FOR A COMPLEX HIERARCHICAL ORGANIZATION
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DOI：
10.1083/jcb.105.1.77
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发表时间：
1987-07-01
影响因子：
7.8
通讯作者：
AGARD, DA
中科院分区：
文献类型：
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作者：
BELMONT, AS;SEDAT, JW;AGARD, DA
我们描述了果蝇黑腹有丝分裂染色体的结构发现，使用三维定向结构方法。利用高压和传统的透射电子显微镜结合轴向断层扫描和数字对比度增强技术，我们首次在最小扰动的有丝分裂染色体中可视化了重要的结构细节。通过几种不同的制备方法制备的染色体显示出一致的离散染色质结构域的大小等级，其横截面直径分别为120、240、400-500和800-1000 ang。在完全浓缩的中期停滞染色体中，有证据表明在1300 - 3000 - 0.ang范围内存在更大规模的结构组织。大小。观察到的这些高阶结构域的染色体内排列表明，染色体结构的径向环和顺序螺旋盘绕模型都是对真实情况的过度简化。最后，我们的研究结果表明，通过有丝分裂的染色质浓缩途径包括在染色质组织的几个水平上同时发生的变化，而不是严格顺序的折叠过程。
We describe findings on the architecture of Drosophila melanogaster mitotic chromosomes, made using a three-dimensional-oriented structural approach. Using high-voltage and conventional transmission electron microscopy combined with axial tomography and digital contrast-enhancement techniques, we have for the first time visualized significant structural detail within minimally perturbed mitotic chromosomes. Chromosomes prepared by several different preparative procedures showed a consistent size hierarchy of discrete chromatin structural domains with cross-sectional diameters of 120, 240, 400-500, and 800-1000 .ANG.. In fully condensed, metaphase-arrested chromosomes, there is evidence for even larger-scale structural organization in the range of 1,300-3,000-.ANG. size. The observed intrachromosomal arrangements of these higher-order structural domains show that both the radial loop and sequential helical coiling models of chromosome structure are over-simplifications of the true situation. Finally, our results suggest that the pathway of chromatin condensation through mitosis consists of concurrent changes occurring at several levels of chromatin organization, rather than a strictly sequential folding process.