Animal Sciences and Health, Institute of Biology, Leiden University, 2333CC Leiden, The Netherlands.
Biological Matter/Living Systems, Institute of Physics, Leiden University, 2333CC Leiden, The Netherlands.
J Cell Sci. 2019 Feb 25;132(5):jcs217455. doi: 10.1242/jcs.217455.
Transcription factor mobility is a determining factor in the regulation of gene expression. Here, we have studied the intranuclear dynamics of the glucocorticoid receptor (GR) by using fluorescence recovery after photobleaching and single-molecule microscopy. First, we have described the dynamic states in which the GR occurs. Second, we have analyzed the transitions between these states by using a continuous-time Markov chain model and functionally investigated these states by making specific mutations in the DNA-binding domain. This analysis revealed that the GR diffuses freely through the nucleus and, once it leaves this free diffusion state, most often enters a repetitive switching mode. In this mode it alternates between slow diffusion as a result of brief nonspecific DNA-binding events, and a state of stable binding to specific DNA target sites. This repetitive switching mechanism results in a compact search strategy that facilitates finding of DNA target sites by the GR.This article has an associated First Person interview with the first author of the paper.
转录因子的迁移性是基因表达调控的决定因素。在这里，我们通过荧光漂白恢复和单分子显微镜研究了糖皮质激素受体（GR）的核内动力学。首先，我们描述了 GR 发生的动态状态。其次，我们通过连续时间马尔可夫链模型分析了这些状态之间的转变，并通过在 DNA 结合域中进行特定突变对这些状态进行了功能研究。该分析表明，GR 可在核内自由扩散，一旦其离开自由扩散状态，通常会进入反复切换模式。在这种模式下，它会在由于短暂的非特异性 DNA 结合事件导致的缓慢扩散和与特定 DNA 靶位点的稳定结合状态之间交替。这种反复切换机制产生了一种紧凑的搜索策略，有助于 GR 找到 DNA 靶位点。本文有一篇与本文第一作者的第一人称访谈。
