EBF1 and PAX5 control pro-B cell expansion via opposing regulation of the Myc gene.
EBF1 and PAX5 control pro-B cell expansion via opposing regulation of the Myc gene.
复制标题
DOI：
10.1182/blood.2020009564
复制
发表时间：
2021-02
期刊：
影响因子：
20.3
通讯作者：
R. Somasundaram;Christina T. Jensen;Johanna Tingvall-Gustafsson;Josefine Åhsberg;K. Okuyama;M. Prasad;J. Hagman;Xun Wang;S. Soneji;Tobias Strid;Jonas Ungerbäck;M. Sigvardsson
中科院分区：
文献类型：
--
作者：
R. Somasundaram;Christina T. Jensen;Johanna Tingvall-Gustafsson;Josefine Åhsberg;K. Okuyama;M. Prasad;J. Hagman;Xun Wang;S. Soneji;Tobias Strid;Jonas Ungerbäck;M. Sigvardsson
编码B谱系限制性转录因子的基因在B淋巴细胞白血病中经常发生突变，表明正常和恶性B细胞发育之间存在密切联系。这些转录因子之一是早期B细胞因子1（EBF 1），一种对于B淋巴祖细胞的谱系特化和存活至关重要的蛋白质。在这里，我们报告说，在小鼠B细胞祖细胞中EBF 1功能受损导致Myc表达减少。MYC的异位表达在体内和体外均在EBF 1不存在的情况下部分挽救了B细胞扩增。使用染色体构象分析结合ATAC-seq，ChIP-seq和报告基因测定，我们确定了Myc基因座内的6个EBF响应增强子元件。CRISPR-Cas9介导的EBF 1结合位点的靶向鉴定了Myc表达和pro-B细胞扩增的一个关键重要因素。这些数据证明Myc是EBF 1的直接靶点。此外，ChIP-seq分析显示，Myc基因座中的几个调控元件是PAX 5的靶标。然而，在EBF 1缺陷细胞中PAX 5的异位表达抑制细胞周期并降低Myc表达，表明EBF 1和PAX 5以相反的方式调节Myc水平。Pax 5失活降低了pro-B细胞扩增中对EBF 1的需求，这一发现进一步证实了这一假设。在B-ALL细胞系中，EBF 1和PAX 5与人MYC基因中的调节元件的结合表明EBF 1：PAX 5：MYC调节环是保守的，并且可以控制正常和恶性B细胞发育。
Genes encoding B lineage restricted transcription factors are frequently mutated in B-lymphoid leukemias, suggesting a close link between normal and malignant B-cell development. One of these transcription factors is Early B cell Factor 1 (EBF1), a protein of critical importance for lineage specification and survival of B-lymphoid progenitors. Here, we report that impaired EBF1 function in mouse B-cell progenitors results in reduced expression of Myc. Ectopic expression of MYC partially rescued B-cell expansion in the absence of EBF1 both in vivo and in vitro. Using chromosome conformation analysis in combination with ATAC-seq, ChIP-seq and reporter gene assays, we identified six EBF responsive enhancer elements within the Myc locus. CRISPR-Cas9 mediated targeting of EBF1 binding sites identified one element of key importance for Myc expression and pro-B cell expansion. These data provide evidence that Myc is a direct target of EBF1. Furthermore, ChIP-seq analysis revealed that several regulatory elements in the Myc locus are targets of PAX5. However, ectopic expression of PAX5 in EBF1 deficient cells inhibits the cell cycle and reduces Myc expression, suggesting that EBF1 and PAX5 act in an opposing manner to regulate Myc levels. This hypothesis is further substantiated by the finding that Pax5 inactivation reduces requirements for EBF1 in pro-B cell expansion. The binding of EBF1 and PAX5 to regulatory elements in the human MYC gene in a B-ALL cell line indicate that the EBF1:PAX5:MYC regulatory loop is conserved and may control both normal and malignant B-cell development.