Terry Fox Laboratory, British Columbia Cancer Research Centre, Vancouver, Canada.
Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
Leukemia. 2022 Aug;36(8):1980-1989. doi: 10.1038/s41375-022-01602-4. Epub 2022 May 27.
Myeloid ecotropic virus insertion site 1 (MEIS1) is essential for normal hematopoiesis and is a critical factor in the pathogenesis of a large subset of acute myeloid leukemia (AML). Despite the clinical relevance of MEIS1, its regulation is largely unknown. To understand the transcriptional regulatory mechanisms contributing to human MEIS1 expression, we created a knock-in green florescent protein (GFP) reporter system at the endogenous MEIS1 locus in a human AML cell line. Using this model, we have delineated and dissected a critical enhancer region of the MEIS1 locus for transcription factor (TF) binding through in silico prediction in combination with oligo pull-down, mass-spectrometry and knockout analysis leading to the identification of FLI1, an E-twenty-six (ETS) transcription factor, as an important regulator of MEIS1 transcription. We further show direct binding of FLI1 to the MEIS1 locus in human AML cell lines as well as enrichment of histone acetylation in MEIS1-high healthy and leukemic cells. We also observe a positive correlation between high FLI1 transcript levels and worse overall survival in AML patients. Our study expands the role of ETS factors in AML and our model constitutes a feasible tool for a more detailed understanding of transcriptional regulatory elements and their interactome.
髓系亲和病毒插入位点 1(MEIS1)对于正常造血至关重要,是一大类急性髓系白血病(AML)发病机制的关键因素。尽管 MEIS1 具有临床相关性,但对其调控机制知之甚少。为了了解有助于人类 MEIS1 表达的转录调控机制,我们在人 AML 细胞系中创建了一个内源性 MEIS1 基因座的 GFP 报告基因敲入系统。使用该模型,我们通过计算机预测与寡核苷酸下拉、质谱和敲除分析相结合,描绘并剖析了 MEIS1 基因座的关键增强子区域,用于转录因子(TF)结合,从而确定 FLI1(一种 ETS 转录因子)是 MEIS1 转录的重要调节因子。我们进一步表明,FLI1 可直接与人类 AML 细胞系中的 MEIS1 基因座结合,以及 MEIS1 高的健康和白血病细胞中组蛋白乙酰化的富集。我们还观察到 AML 患者中高 FLI1 转录本水平与总体生存率较差之间存在正相关。我们的研究扩展了 ETS 因子在 AML 中的作用,我们的模型构成了一个可行的工具,可更详细地了解转录调控元件及其相互作用组。