CHROMATIN RECONSTITUTION ON SMALL DNA RINGS .3. HISTONE H5 DEPENDENCE OF DNA SUPERCOILING IN THE NUCLEOSOME
CHROMATIN RECONSTITUTION ON SMALL DNA RINGS .3. HISTONE H5 DEPENDENCE OF DNA SUPERCOILING IN THE NUCLEOSOME
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DOI：
10.1016/0022-2836(90)90195-r
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发表时间：
1990-07-20
影响因子：
5.6
通讯作者：
PRUNELL, A
中科院分区：
文献类型：
--
作者：
ZIVANOVIC, Y;DUBANDGOULET, I;PRUNELL, A
在组蛋白 H5 存在的情况下，在小 DNA 环上重构单核小体，并使用小牛胸腺拓扑异构酶 I 松弛至平衡。与在不存在组蛋白的情况下用相同小环观察到的平衡相比，DNA 产品表明，与这种重构相关的连接数减少了 1.6 至 1.7，与我们最近的无 H5 研究中报道的 1.1 至 1.2 数字形成鲜明对比。核小体。核小体的凝胶电泳特性和电子显微镜可视化表明，这种增加与 DNA 进一步包裹组蛋白核心之间存在相关性，从不存在 H5 时超螺旋的不到 1.5 圈，到 H5 存在时接近两圈。讨论了染色质中 DNA 拓扑结构的影响。
Mononucleosomes were reconstituted on small DNA rings in the presence of histone H5 and relaxed to an equilibrium using calf thymus topoisomerase I. DNA products, when compared to the equilibria observed with the same minicircles in the absence of histones, showed that a linking number reduction of 1.6 to 1.7 was associated with this reconstitution, in contrast with the 1.1 to 1.2 figure reported in our recent study of the H5-free nucleosome. Gel electrophoretic properties and electron microscopic visualization of the nucleosomes suggest a correlation between this increase and a further wrapping of the DNA around the histone core from less than 1.5 turns of the superhelix in the absence of H5, to close to two turns in its presence. Implications for DNA topology in chromatin are discussed.