Alerasool Nader, Leng He, Lin Zhen-Yuan, Gingras Anne-Claude, Taipale Mikko
Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
Mol Cell. 2022 Feb 3;82(3):677-695.e7. doi: 10.1016/j.molcel.2021.12.008. Epub 2022 Jan 10.
Transcription is orchestrated by thousands of transcription factors (TFs) and chromatin-associated proteins, but how these are causally connected to transcriptional activation is poorly understood. Here, we conduct an unbiased proteome-scale screen to systematically uncover human proteins that activate transcription in a natural chromatin context. By combining interaction proteomics and chemical inhibitors, we delineate the preference of these transcriptional activators for specific co-activators, highlighting how even closely related TFs can function via distinct cofactors. We also identify potent transactivation domains among the hits and use AlphaFold2 to predict and experimentally validate interaction interfaces of two activation domains with BRD4. Finally, we show that many novel activators are partners in fusion events in tumors and functionally characterize a myofibroma-associated fusion between SRF and C3orf62, a potent p300-dependent activator. Our work provides a functional catalog of potent transactivators in the human proteome and a platform for discovering transcriptional regulators at genome scale.
转录由数千种转录因子（TFs）和染色质相关蛋白精心调控，但它们与转录激活之间的因果关系却知之甚少。在这里，我们进行了一项无偏向性的蛋白质组规模筛选，以系统地发现能够在天然染色质环境中激活转录的人类蛋白质。通过结合相互作用蛋白质组学和化学抑制剂，我们描绘了这些转录激活因子对特定共激活因子的偏好，突出了即使是密切相关的TFs也可以通过不同的辅因子发挥作用。我们还在筛选结果中鉴定出了有效的反式激活结构域，并使用AlphaFold2预测并通过实验验证了两个激活结构域与BRD4的相互作用界面。最后，我们表明许多新型激活因子是肿瘤融合事件中的伙伴，并对SRF和C3orf62之间与肌纤维瘤相关的融合进行了功能表征，这是一种有效的p300依赖性激活因子。我们的工作提供了一份人类蛋白质组中有效反式激活因子的功能目录，以及一个在基因组规模上发现转录调节因子的平台。
