European Molecular Biology Laboratory (EMBL) Australia, Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia.
Nat Commun. 2013;4:1637. doi: 10.1038/ncomms2657.
Transcription factors use diffusion to search the DNA, yet the mechanisms controlling transcription factor diffusion during mammalian development remain poorly understood. Here we combine photoactivation and fluorescence correlation spectroscopy to study transcription factor diffusion in developing mouse embryos. We show that the pluripotency-associated transcription factor Oct4 displays both fast and Brownian and slower subdiffusive behaviours that are controlled by DNA interactions. Following cell lineage specification, the slower DNA-interacting diffusion fraction distinguishes pluripotent from extraembryonic cell nuclei. Similar to Oct4, Sox2 shows slower diffusion in pluripotent cells while Cdx2 displays opposite dynamics, suggesting that slow diffusion may represent a general feature of transcription factors in lineages where they are essential. Slow Oct4 subdiffusive behaviours are conserved in embryonic stem cells and induced pluripotent stem cells (iPS cells), and lost during differentiation. We also show that Oct4 diffusion depends on its interaction with ERG-associated protein with SET domain. Photoactivation and fluorescence correlation spectroscopy provides a new intravital approach to study transcription factor diffusion in complex in vivo systems.
转录因子利用扩散来搜索 DNA，但在哺乳动物发育过程中控制转录因子扩散的机制仍知之甚少。在这里，我们结合光激活和荧光相关光谱法来研究发育中的小鼠胚胎中的转录因子扩散。我们表明，多能相关转录因子 Oct4 显示出快速和布朗以及较慢的亚扩散行为，这些行为受 DNA 相互作用的控制。在细胞谱系特化后，较慢的 DNA 相互作用扩散分数区分多能性和胚胎外细胞核。类似于 Oct4，Sox2 在多能性细胞中显示出较慢的扩散，而 Cdx2 显示出相反的动力学，表明慢扩散可能是它们在必需的谱系中作为转录因子的一般特征。慢 Oct4 亚扩散行为在胚胎干细胞和诱导多能干细胞 (iPS 细胞) 中得到保守，并且在分化过程中丢失。我们还表明，Oct4 扩散取决于其与 ERG 相关蛋白的 SET 结构域的相互作用。光激活和荧光相关光谱法为在复杂的体内系统中研究转录因子扩散提供了一种新的活体方法。
