Zhang Hao, Zhang Yang, Zhou Xinyue, Wright Shaela, Hyle Judith, Zhao Lianzhong, An Jie, Zhao Xujie, Shao Ying, Xu Beisi, Lee Hyeong-Min, Chen Taosheng, Zhou Yang, Chen Xiang, Lu Rui, Li Chunliang
Division of Hematology/Oncology, University of Alabama at Birmingham, Birmingham, United States.
O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, United States.
Elife. 2020 Oct 1;9:e57858. doi: 10.7554/eLife.57858.
Aberrant expression is a hallmark of most aggressive acute leukemias, notably those with KMT2A (MLL) gene rearrangements. overexpression not only predicts poor diagnosis and outcome but also plays a critical role in leukemia transformation and maintenance. However, our current understanding of regulation in leukemia is limited, hindering development of therapeutic strategies. Here, we generated the knock-in reporter cell lines to dissect regulation. By utilizing the reporter and CRISPR/Cas9 screens, we identified transcription factors controlling expression, including a novel regulator, USF2, whose depletion significantly down-regulated expression and impaired MLLr leukemia cell proliferation. Ectopic expression of Hoxa9 rescued impaired leukemia cell proliferation upon USF2 loss. Cut and Run analysis revealed the direct occupancy of USF2 at promoter in MLLr leukemia cells. Collectively, the reporter facilitated the functional interrogation of the regulome and has advanced our understanding of the molecular regulation network in -driven leukemia.
异常表达是大多数侵袭性急性白血病的一个标志，尤其是那些具有KMT2A（MLL）基因重排的白血病。其过表达不仅预示着诊断不佳和预后不良，而且在白血病转化和维持中起着关键作用。然而，我们目前对白血病中该基因调控的理解有限，这阻碍了治疗策略的发展。在这里，我们生成了敲入报告细胞系来剖析其调控机制。通过利用报告基因和CRISPR/Cas9筛选，我们鉴定了控制该基因表达的转录因子，包括一个新的调节因子USF2，其缺失显著下调了该基因的表达并损害了MLLr白血病细胞的增殖。Hoxa9的异位表达挽救了USF2缺失时受损的白血病细胞增殖。Cut and Run分析揭示了USF2在MLLr白血病细胞中该基因启动子上的直接占据。总的来说，该报告基因促进了对该基因调控组的功能研究，并加深了我们对该基因驱动的白血病分子调控网络的理解。
