Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China.
National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China.
Cell Death Dis. 2021 Feb 26;12(2):223. doi: 10.1038/s41419-021-03515-z.
MYB plays vital roles in regulating proliferation and differentiation of hematopoietic progenitor cells, dysregulation of MYB has been implicated in the pathogenesis of leukemia. Although the transcription of MYB has been well studied, its detailed underlying regulatory mechanisms still remain elusive. Here, we detected the long-range interaction between the upstream regions, -34k and -88k, and the MYB promoter in K562, U937, and HL-60 cells using circularized chromosome conformation capture (4C) assay, which declined when MYB was downregulated during chemical-induced differentiation. The enrichment of enhancer markers, H3K4me1 and H3K27ac, and enhancer activity at the -34k and -88k regions were confirmed by ChIP-qPCR and luciferase assay respectively. ChIP-qPCR showed the dynamic binding of GATA1, TAL1, and CCAAT/enhancer-binding protein (C/EBPβ) at -34k and -88k during differentiation of K562 cells. Epigenome editing by a CRISPR-Cas9-based method showed that H3K27ac at -34k enhanced TF binding and MYB expression, while DNA methylation inhibited MYB expression. Taken together, our data revealed that enhancer elements at -34k are required for MYB expression, TF binding, and epigenetic modification are closely involved in this process in human myeloid leukemia cells.
MYB 在调节造血祖细胞的增殖和分化中发挥着重要作用，MYB 的失调与白血病的发病机制有关。尽管 MYB 的转录已经得到了很好的研究，但它的详细的潜在调控机制仍然难以捉摸。在这里，我们使用圆形染色体构象捕获（4C）实验检测了 K562、U937 和 HL-60 细胞中上游区域 -34k 和 -88k 与 MYB 启动子之间的长程相互作用，当 MYB 在化学诱导分化过程中下调时，这种相互作用减弱。通过 ChIP-qPCR 和荧光素酶测定分别证实了 -34k 和 -88k 区域增强子标记物 H3K4me1 和 H3K27ac 的富集和增强子活性。ChIP-qPCR 显示 GATA1、TAL1 和 CCAAT/增强子结合蛋白（C/EBPβ）在 K562 细胞分化过程中在 -34k 和 -88k 处的动态结合。基于 CRISPR-Cas9 的表观基因组编辑表明，-34k 处的 H3K27ac 增强了 TF 结合和 MYB 表达，而 DNA 甲基化抑制了 MYB 表达。总之，我们的数据表明 -34k 处的增强子元件是 MYB 表达所必需的，TF 结合和表观遗传修饰在人类髓系白血病细胞中密切参与了这一过程。
