HOTAIR is a long noncoding RNA (lncRNA) which serves as an important factor regulating diverse processes linked with cancer development. Here, we used comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS) to explore the HOTAIR-protein interactome. We were able to identify 348 proteins interacting with HOTAIR, allowing us to establish a heavily interconnected HOTAIR-protein interaction network. We further developed a novel near-infrared fluorescent protein (iRFP)-trimolecular fluorescence complementation (TriFC) system to assess the interaction between HOTAIR and its interacting proteins. Then, we determined that HOTAIR specifically binds to YBX1, promotes YBX1 nuclear translocation, and stimulates the PI3K/Akt and ERK/RSK signaling pathways. We further demonstrated that HOTAIR exerts its effects on cell proliferation, at least in part, through the regulation of two YBX1 downstream targets phosphoenolpyruvate carboxykinase 2 (PCK2) and platelet derived growth factor receptor β. Our findings revealed a novel mechanism, whereby an lncRNA is able to regulate cell proliferation via altering intracellular protein localization. Moreover, the imaging tools developed herein have excellent potential for future in vivo imaging of lncRNA-protein interaction.

中文翻译：

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长链非编码 RNA HOTAIR 与 Y-Box Protein-1 (YBX1) 相互作用以调节细胞增殖。

HOTAIR 是一种长链非编码 RNA (lncRNA)，它是调节与癌症发展相关的多种过程的重要因素。在这里，我们使用质谱法 (ChIRP-MS) 对 RNA 结合蛋白的综合鉴定来探索 HOTAIR 蛋白相互作用组。我们能够识别出 348 种与 HOTAIR 相互作用的蛋白质，从而使我们能够建立一个高度互联的 HOTAIR-蛋白质相互作用网络。我们进一步开发了一种新型近红外荧光蛋白 (iRFP)-三分子荧光互补 (TriFC) 系统来评估 HOTAIR 与其相互作用蛋白之间的相互作用。然后，我们确定 HOTAIR 特异性结合 YBX1，促进 YBX1 核转位，并刺激 PI3K/Akt 和 ERK/RSK 信号通路。我们进一步证明了 HOTAIR 对细胞增殖有影响，至少部分是通过调节两个 YBX1 下游靶标磷酸烯醇丙酮酸羧激酶 2 (PCK2) 和血小板衍生的生长因子受体 β。我们的研究结果揭示了一种新机制，即 lncRNA 能够通过改变细胞内蛋白质定位来调节细胞增殖。此外，本文开发的成像工具在未来对 lncRNA-蛋白质相互作用的体内成像方面具有极好的潜力。