染色质重构：核小体的组装

Wilhelm F X, Wilhelm M L, Erard M, Duane M P

Nucleic Acids Res. 1978 Feb;5(2):505-21. doi: 10.1093/nar/5.2.505.

The order of reassociation of the four histones H2a, H2b, H3 and H4 to the DNA during the reconstitution of chromatin was determined. At each step of the reconstitution the DNA and associated histones were separated from the free histones by centrifugation in a glycerol gradient. The unbound and reassociated histones were analysed by gel electrophoresis and the histone-DNA complexes characterized by circular dichroism and electron microscopy. We show that H3 and H4 bind first to the DNA between 1.2 M NaCl and 0.85 M NaCl and impose a nucleosome like structure; in a second step histones H2a and H2b are placed around this kernel to complete the nucleosome.

确定了在染色质重构过程中四种组蛋白H2a、H2b、H3和H4与DNA重新结合的顺序。在重构的每个步骤中，通过在甘油梯度中离心将DNA和相关组蛋白与游离组蛋白分离。通过凝胶电泳分析未结合和重新结合的组蛋白，并通过圆二色性和电子显微镜对组蛋白-DNA复合物进行表征。我们发现，H3和H4首先在1.2M NaCl和0.85M NaCl之间与DNA结合，并形成类似核小体的结构；在第二步中，组蛋白H2a和H2b围绕这个核心排列以完成核小体的形成。