Continuous histone H2B and transcription-dependent histone H3 exchange in yeast cells outside of replication
Continuous histone H2B and transcription-dependent histone H3 exchange in yeast cells outside of replication
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DOI：
10.1016/j.molcel.2007.01.019
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发表时间：
2007-02-09
期刊：
影响因子：
16
通讯作者：
Strubin, Michel
中科院分区：
文献类型：
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作者：
Jamai, Adil;Imoberdorf, Rachel Maria;Strubin, Michel
我们研究了酵母中组蛋白-DNA相互作用的动力学，通过使用表位标记的组蛋白H2 B和H3的诱导形式。新合成的组蛋白的染色质组装通过染色质免疫沉淀在G1期阻滞的细胞中进行评估，以防止复制偶联的组蛋白掺入。我们发现，虽然组蛋白沉积在一个subtelomeric区域内是严格连接到DNA复制，组蛋白H2 B是连续掺入在启动子和编码区的转录活性和非活性位点。相反，组蛋白H3的掺入仅发生在活性基因处，在启动子处占主导地位，并显示出与平均核小体密度呈负相关的基因沿着动态。用N-末端截短的H2 B和H3变体获得了类似的结果。我们推断，H2 B和H3的复制独立的掺入是不同的事件，各自独立于组蛋白尾部发生，并且在活性启动子处的核小体损失反映了组蛋白沉积和解离之间的动态平衡。
We investigated the dynamics of histone-DNA interactions in yeast by using inducible forms of epitope-tagged histones H2B and H3. Chromatin assembly of newly synthesized histones was assessed by chromatin immunoprecipitation in G1-arrested cells to prevent replication-coupled histone incorporation. We find that while histone deposition within a subtelomeric region is strictly linked to DNA replication, histone H2B is continuously incorporated at the promoter and coding regions of both transcriptionally active and inactive loci. In contrast, incorporation of histone H3 occurs only at active genes, being predominant at the promoter and showing a dynamics along the gene that inversely correlates with the average nucleosomal density. Similar results were obtained with N-terminally truncated H2B and H3 variants. We infer that replication-independent incorporation of H2B and H3 are distinct events, each occurring independently of the histone tail, and that nucleosome loss at active promoters reflects a dynamic equilibrium between histone deposition and dissociation.