ALTERNATIVE CHROMATIN STRUCTURE AT CPG ISLANDS
ALTERNATIVE CHROMATIN STRUCTURE AT CPG ISLANDS
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DOI：
10.1016/0092-8674(90)90339-g
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发表时间：
1990-03-23
期刊：
影响因子：
64.5
通讯作者：
BIRD, A
中科院分区：
文献类型：
--
作者：
TAZI, J;BIRD, A
活性转录的染色质在结构上与大量非活性染色质不同。然而，很难确定差异的分子基础，因为无法获得活性染色质的纯化部分。我们通过使用限制性核酸内切酶从 HeLa 细胞核的富含非甲基化 CpG 的岛（CpG 岛）中释放寡核小体，克服了这个问题。由于 CpG 岛通常包含启动子和基因的 5'' 转录区域，因此它们代表了“活跃”染色质结构的模型。 CpG 岛染色质与以相同方式制备的本体染色质在三个方面有所不同：组蛋白 H1 的含量非常低；组蛋白 H3 和 H4 高度乙酰化；且存在无核小体区域。除了后面的区域外，平均核小体间距与大量染色质的间距相似。
Actively transcribed chromatin is structurally different from bulk inactive chromatin. It has been difficult to define the molecular basis of the difference, however, because purified fractions of active chromatin were not available. We have overcome this problem by releasing oligonucleosomes from the nonmethylated CpG-rich islands (CpG islands) of HeLa cell nuclei using restriction endonucleases. Since CpG islands very often include the promoters and 5'' transcribed regions of genes, they represent a model for the "active" chromatin structure. CpG island chromatin differs in three respects from bulk chromatin prepared in the same way: histone H1 is present in very low amounts; histones H3 and H4 are highly acetylated; and nucleosome-free regions are present. Except for the latter regions, the average nucleosomal spacing is similar to that of bulk chromatin.