Cell cycle-dependent changes in conformation and composition of nucleosomes containing human histone gene sequences.
Cell cycle-dependent changes in conformation and composition of nucleosomes containing human histone gene sequences.
复制标题
含有人类组蛋白基因序列的核小体的构象和组成的细胞周期依赖性变化。
DOI：
10.1093/nar/15.11.4375
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发表时间：
1987
影响因子：
14.9
通讯作者：
Allfrey,VG
中科院分区：
文献类型：
--
作者：
Sterner,R;Boffa,LC;Chen,TA;Allfrey,VG
核小体在转录活性染色质中的展开揭示了组蛋白H3的巯基，并允许通过汞亲和层析选择性地回收未折叠的核小体。这种新的技术已被用来比较的核小体蛋白质和它们的合成后的修改在展开和compendescribed珠的HeLa细胞的核小体在对数生长，并在不同阶段的生长周期。汞结合的核小体被证明是在复制DNA序列的缺陷，但仍然与新生RNA链（或RNP颗粒）的片段在梯度离心。两个核小体组分都含有完整的“核心”组蛋白，但在合成后修饰方面有所不同。汞结合的核小体含有高水平的组蛋白H3和H4的三乙酰化和四乙酰化形式。未结合的核小体缺乏乙酰化组蛋白，但富含磷酸化H2A。在同步化的HeLa细胞中，组蛋白H2 A和H4基因序列在S期（转录发生时）出现在汞结合的核小体中，但在G2期（基因被抑制时）则不出现。
Unfolding of the nucleosomes in transcriptionally active chromatin uncovers the sulfhydryl groups of histone H3 and permits the selective recovery of the unfolded nucleosomes by mercury-affinity chromatography. This new technique has been used to compare the nucleosomal proteins and their postsynthetic modifications in the unfolded and the compactly beaded nucleosomes of HeLa cells in logarithmic growth, and at different stages of the growth cycle. The Hg-bound nucleosomes are shown to be deficient in replicating DNA sequences, but to remain associated with fragments of nascent RNA chains (or RNP particles) during gradient centrifugations. Both nucleosome fractions contain a full complement of “core” histones but differ with respect to postsynthetic modifications. The Hg-bound nucleosomes contain high levels of the tri- and tetra-acetylated forms of histones H3 and H4. The unbound nucleosomes are deficient in acetylated histones but enriched in phosphorylated H2A. In synchronized HeLa cells, histone H2A and H4 gene sequences occur in the Hg-bound nucleosomes during the S-phase when their transcription takes place, but not in the G2-phase when the genes are repressed.