Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Mol Cell. 2022 Jun 2;82(11):2084-2097.e5. doi: 10.1016/j.molcel.2022.04.007. Epub 2022 Apr 27.
Gene activation by mammalian transcription factors (TFs) requires multivalent interactions of their low-complexity domains (LCDs), but how such interactions regulate transcription remains unclear. It has been proposed that extensive LCD-LCD interactions culminating in liquid-liquid phase separation (LLPS) of TFs is the dominant mechanism underlying transactivation. Here, we investigated how tuning the amount and localization of LCD-LCD interactions in vivo affects transcription of endogenous human genes. Quantitative single-cell and single-molecule imaging reveals that the oncogenic TF EWS::FLI1 requires a narrow optimum of LCD-LCD interactions to activate its target genes associated with GGAA microsatellites. Increasing LCD-LCD interactions toward putative LLPS represses transcription of these genes in patient-derived cells. Likewise, ectopically creating LCD-LCD interactions to sequester EWS::FLI1 into a well-documented LLPS compartment, the nucleolus, inhibits EWS::FLI1-driven transcription and oncogenic transformation. Our findings show how altering the balance of LCD-LCD interactions can influence transcriptional regulation and suggest a potential therapeutic strategy for targeting disease-causing TFs.
哺乳动物转录因子（TFs）的基因激活需要其低复杂度结构域（LCDs）的多价相互作用，但这种相互作用如何调节转录仍不清楚。有人提出，TFs 中广泛的 LCD-LCD 相互作用最终导致液-液相分离（LLPS）是转录激活的主要机制。在这里，我们研究了在体内调节 LCD-LCD 相互作用的数量和定位如何影响内源性人基因的转录。定量单细胞和单分子成像揭示，致癌 TF EWS::FLI1 需要一个狭窄的最佳 LCD-LCD 相互作用来激活其与 GGAA 微卫星相关的靶基因。朝着可能的 LLPS 增加 LCD-LCD 相互作用会抑制患者来源细胞中这些基因的转录。同样，异位创建 LCD-LCD 相互作用将 EWS::FLI1 隔离到一个有充分文献记载的 LLPS 隔室——核仁中，会抑制 EWS::FLI1 驱动的转录和致癌转化。我们的研究结果表明，改变 LCD-LCD 相互作用的平衡如何影响转录调控，并为针对致病 TF 的治疗策略提供了潜在的思路。
