Belikov S, Gelius B, Almouzni G, Wrange O
Laboratory of Molecular Genetics, Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institutet, SE-17177 Stockholm, Sweden.
EMBO J. 2000 Mar 1;19(5):1023-33. doi: 10.1093/emboj/19.5.1023.
The mouse mammary tumor virus (MMTV) promoter is induced by glucocorticoid hormone. A robust hormone- and receptor-dependent activation could be reproduced in Xenopus laevis oocytes. The homogeneous response in this system allowed a detailed analysis of the transition in chromatin structure following hormone activation. This revealed two novel findings: hormone activation led to the establishment of specific translational positioning of nucleosomes despite the lack of significant positioning in the inactive state; and, in the active promoter, a subnucleosomal particle encompassing the glucocorticoid receptor (GR)-binding region was detected. The presence of only a single GR-binding site was sufficient for the structural transition to occur. Both basal promoter elements and ongoing transcription were dispensable. These data reveal a stepwise process in the transcriptional activation by glucocorticoid hormone.
小鼠乳腺肿瘤病毒（MMTV）启动子受糖皮质激素诱导。在非洲爪蟾卵母细胞中可重现强烈的激素和受体依赖性激活。该系统中的均匀反应使得能够详细分析激素激活后染色质结构的转变。这揭示了两个新发现：尽管在非活性状态下缺乏明显的定位，但激素激活导致核小体特定翻译定位的建立；并且，在活性启动子中，检测到一个包含糖皮质激素受体（GR）结合区域的亚核小体颗粒。仅存在单个GR结合位点就足以发生结构转变。基础启动子元件和正在进行的转录都是不必要的。这些数据揭示了糖皮质激素转录激活的一个逐步过程。
