Quantitative imaging of chromatin decompaction in living cells.
Quantitative imaging of chromatin decompaction in living cells.
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DOI：
10.1091/mbc.e17-11-0648
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发表时间：
2018-07-15
影响因子：
3.3
通讯作者：
Weis K
中科院分区：
文献类型：
--
作者：
Dultz E;Mancini R;Polles G;Vallotton P;Alber F;Weis K
染色质组织高度动态并调节转录。转录激活后，染色质被重塑并被称为“开放”，但缺乏这种解压缩过程的定量和动态数据。在这里，我们在活酵母细胞中开发了一种定量高分辨率显微镜测定法，使用 GAL7-10-1 基因座作为模型系统来可视化和量化染色质动态。在这三个聚集基因的转录激活后，我们检测到该基因座的平均距离增加了 >100 nm。这种解压缩与活性转录有关，但对组蛋白脱乙酰酶抑制剂曲古抑菌素 A 或组蛋白乙酰转移酶 Gcn5 的缺失不敏感。相反，SNF2（编码 SWI/SNF 染色质重塑复合物的 ATP 酶）的缺失或组蛋白伴侣复合物 FACT 的失活会导致解压强烈减少，但对 FACT 突变体的转录诱导没有显着影响。我们的研究结果与核小体重塑和驱逐活动是转录过程中染色质重组的主要贡献者一致，但也表明转录可以在没有可检测到的解压缩的情况下发生。
Chromatin organization is highly dynamic and regulates transcription. Upon transcriptional activation, chromatin is remodeled and referred to as “open,” but quantitative and dynamic data of this decompaction process are lacking. Here, we have developed a quantitative high resolution–microscopy assay in living yeast cells to visualize and quantify chromatin dynamics using the GAL7-10-1 locus as a model system. Upon transcriptional activation of these three clustered genes, we detect an increase of the mean distance across this locus by >100 nm. This decompaction is linked to active transcription but is not sensitive to the histone deacetylase inhibitor trichostatin A or to deletion of the histone acetyl transferase Gcn5. In contrast, the deletion of SNF2 (encoding the ATPase of the SWI/SNF chromatin remodeling complex) or the deactivation of the histone chaperone complex FACT lead to a strongly reduced decompaction without significant effects on transcriptional induction in FACT mutants. Our findings are consistent with nucleosome remodeling and eviction activities being major contributors to chromatin reorganization during transcription but also suggest that transcription can occur in the absence of detectable decompaction.