Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Building 41, 41 Library Drive, Bethesda, Maryland 20892, USA.
Istituto Scientifico Ospedale San Raffaele, Centro di Imaging Sperimentale e Università Vita-Salute San Raffaele, 20132 Milano, Italy.
Nat Commun. 2017 Jun 21;8:15896. doi: 10.1038/ncomms15896.
Population-based assays have been employed extensively to investigate the interactions of transcription factors (TFs) with chromatin and are often interpreted in terms of static and sequential binding. However, fluorescence microscopy techniques reveal a more dynamic binding behaviour of TFs in live cells. Here we analyse the strengths and limitations of in vivo single-molecule tracking and performed a comprehensive analysis on the intranuclear dwell times of four steroid receptors and a number of known cofactors. While the absolute residence times estimates can depend on imaging acquisition parameters due to sampling bias, our results indicate that only a small proportion of factors are specifically bound to chromatin at any given time. Interestingly, the glucocorticoid receptor and its cofactors affect each other's dwell times in an asymmetric manner. Overall, our data indicate transient rather than stable TF-cofactors chromatin interactions at response elements at the single-molecule level.
基于人群的检测已被广泛应用于研究转录因子（TFs）与染色质的相互作用，并常常从静态和顺序结合的角度进行解释。然而，荧光显微镜技术揭示了 TF 在活细胞中更具动态的结合行为。在这里，我们分析了体内单分子追踪的优缺点，并对四种甾体激素受体和一些已知的共因子的核内停留时间进行了全面分析。虽然由于采样偏差，绝对停留时间的估计可能取决于成像采集参数，但我们的结果表明，在任何给定时间，只有一小部分因子特异性地与染色质结合。有趣的是，糖皮质激素受体及其共因子以非对称的方式影响彼此的停留时间。总的来说，我们的数据表明，在单分子水平上，转录因子-共因子与反应元件的染色质相互作用是短暂的，而不是稳定的。
