Hendzel M J, Davie J R
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Biochem J. 1990 Oct 1;271(1):67-73. doi: 10.1042/bj2710067.
The incorporation of newly synthesized histones among various chromatin fraction isolated from non-replicating cell-cycle-phase-Go chicken immature erythrocytes was investigated. We find that newly synthesized erythroid-specific histone Hl variant H5, is incorporated randomly into chromatin. In contrast, newly synthesized nucleosomal histones H2A, H2A.Z, H2B, H3.3, and H4 are preferentially found in a fraction that is highly enriched in active/competent gene chromatin fragments and depleted in repressed gene chromatin. Moreover, ubiquitinated species of histones H2A and H2B and hyperacetylated species of H4 and H2B, which are complexed to active DNA, are labelled. These observations provide evidence that newly synthesized histones preferentially exchange with the nucleosomal histones of transcriptionally active/component chromatin domains. The results of this study suggest that nucleosomes of active chromatin may be inherently less stable than bulk nucleosomes in vivo and have implications for chromatin remodelling.
研究了从处于非复制细胞周期G0期的鸡未成熟红细胞中分离出的各种染色质组分中新合成组蛋白的掺入情况。我们发现，新合成的红细胞特异性组蛋白H1变体H5随机掺入染色质中。相比之下，新合成的核小体组蛋白H2A、H2A.Z、H2B、H3.3和H4优先存在于一个富含活性/有活性基因染色质片段且抑制基因染色质含量低的组分中。此外，与活性DNA结合的组蛋白H2A和H2B的泛素化形式以及H4和H2B的高乙酰化形式也被标记。这些观察结果证明新合成的组蛋白优先与转录活性/有活性染色质结构域的核小体组蛋白进行交换。本研究结果表明，活性染色质的核小体在体内可能固有地比整体核小体更不稳定，这对染色质重塑具有重要意义。
