Transcriptional Auto-Regulation of RUNX1 P1 Promoter.
Transcriptional Auto-Regulation of RUNX1 P1 Promoter.
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DOI：
10.1371/journal.pone.0149119
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Gutierrez SE
中科院分区：
文献类型：
--
作者：
Martinez M;Hinojosa M;Trombly D;Morin V;Stein J;Stein G;Javed A;Gutierrez SE
RUNX1 是矮相关转录因子 (RUNX) 家族的成员，对于造血至关重要。 RUNX1基因的表达由两个启动子控制；远端 P1 启动子和近端 P2 启动子。 RUNX1 mRNA 的几种亚型是通过使用启动子和选择性剪接产生的。这些亚型不仅在时间表达模式上存在差异，而且在组织特异性上也表现出差异。源自 P2 的 RUNX1 同工型在多种组织中表达，但源自 P1 的同工型的表达仅限于造血谱系的细胞。然而，人们对造血细胞特异性表达的控制知之甚少。在这里，我们报告了 RUNX1 蛋白对 P1 衍生的 RUNX1 mRNA 的调节。 P1 启动子的计算机分析显示，转录起始位点上游 0.6kb 处存在两个进化保守的 RUNX 基序，5’UTR 170bp 内存在三个 RUNX 基序。在骨髓细胞和 T 细胞中研究了这些 RUNX 基序的转录贡献。包含所有位点的 RUNX1 基因组片段在两种细胞类型中均显示出非常低的基础活性。 UTR 中 RUNX 基序的突变或缺失会增强 RUNX1 启动子的基础活性。染色质免疫沉淀显示 RUNX1 蛋白被招募到这些位点。 RUNX1 在非造血细胞中的过度表达导致 RUNX1 P1 启动子的剂量依赖性激活。我们还证明 RUNX1 蛋白调节 T 细胞中内源性 RUNX1 mRNA 的转录。最后，我们证明 SCL 转录因子被招募到启动子和 UTR 中含有 RUNX 基序的区域，并在体外调节 RUNX1 P1 启动子的活性。因此，多种证据表明 RUNX1 蛋白调节其自身的基因转录。
RUNX1 a member of the family of runt related transcription factors (RUNX), is essential for hematopoiesis. The expression of RUNX1 gene is controlled by two promoters; the distal P1 promoter and the proximal P2 promoter. Several isoforms of RUNX1 mRNA are generated through the use of both promoters and alternative splicing. These isoforms not only differs in their temporal expression pattern but also exhibit differences in tissue specificity. The RUNX1 isoforms derived from P2 are expressed in a variety of tissues, but expression of P1-derived isoform is restricted to cells of hematopoietic lineage. However, the control of hematopoietic-cell specific expression is poorly understood. Here we report regulation of P1-derived RUNX1 mRNA by RUNX1 protein. In silico analysis of P1 promoter revealed presence of two evolutionary conserved RUNX motifs, 0.6kb upstream of the transcription start site, and three RUNX motifs within 170bp of the 5’UTR. Transcriptional contribution of these RUNX motifs was studied in myeloid and T-cells. RUNX1 genomic fragment containing all sites show very low basal activity in both cell types. Mutation or deletion of RUNX motifs in the UTR enhances basal activity of the RUNX1 promoter. Chromatin immunoprecipitation revealed that RUNX1 protein is recruited to these sites. Overexpression of RUNX1 in non-hematopoietic cells results in a dose dependent activation of the RUNX1 P1 promoter. We also demonstrate that RUNX1 protein regulates transcription of endogenous RUNX1 mRNA in T-cell. Finally we show that SCL transcription factor is recruited to regions containing RUNX motifs in the promoter and the UTR and regulates activity of the RUNX1 P1 promoter in vitro. Thus, multiple lines of evidence show that RUNX1 protein regulates its own gene transcription.