Fli1, Elf1, and Ets1 regulate the proximal promoter of the LMO2 gene in endothelial cells
Fli1, Elf1, and Ets1 regulate the proximal promoter of the LMO2 gene in endothelial cells
复制标题
DOI：
10.1182/blood-2004-12-4755
复制
发表时间：
2005-10-15
期刊：
影响因子：
20.3
通讯作者：
Göttgens, B
中科院分区：
文献类型：
--
作者：
Landry, JR;Kinston, S;Göttgens, B
转录调控已被确定为调节造血干细胞的形成和随后的行为的关键机制。我们已经使用了比较基因组学的方法来确定LMO 2基因的转录调控元件，转录辅因子最初确定通过其参与T细胞白血病，随后被证明是至关重要的正常造血和内皮细胞的发展。在2个先前表征的LMO 2启动子中，第二个（近端）启动子在从哺乳动物到鱼类的脊椎动物中高度保守。实时逆转录-聚合酶链反应（RT-PCR）表达分析确定该启动子为造血组织中转录的主要来源。瞬时和稳定转染表明，近端启动子在造血祖细胞和内皮细胞系中是活跃的，并且这种活性被证明依赖于3个保守的Ets位点，这些位点在体内被E74样因子1（Elf 1）、Friend白血病整合1（Fli 1）和成红细胞增多症病毒癌基因同源物E26 -1（Ets 1）结合。最后，转基因分析表明，LMO 2近端启动子足以在体内内皮细胞中表达。没有观察到造血表达，表明需要额外的增强子来介导造血细胞中近端启动子的转录。总之，这些结果表明，保守的近端启动子是造血和内皮细胞中LMO 2转录的中心，在那里它是由Ets因子调节的。
Transcriptional control has been identified as a key mechanism regulating the formation and subsequent behavior of hematopoietic stem cells. We have used a comparative genomics approach to identify transcriptional regulatory elements of the LMO2 gene, a transcriptional cofactor originally identified through its involvement in T-cell leukemia and subsequently shown to be critical for normal hematopoietic and endothelial development. Of the 2 previously characterized LMO2 promoters, the second (proximal) promoter was highly conserved in vertebrates ranging from mammals to fish. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) expression analysis identified this promoter as the predominant source of transcription in hematopoietic tissue. Transient and stable transfections indicated that the proximal promoter was active in hematopoietic progenitor and endothelial cell lines and this activity was shown to depend on 3 conserved Ets sites that were bound in vivo by E74-like factor 1 (Elf1), Friend leukemia integration 1 (Fli1), and erythroblastosis virus oncogene homolog E twenty-six-1 (Ets1). Finally, transgenic analysis demonstrated that the LMO2 proximal promoter is sufficient for expression in endothelial cells in vivo. No hematopoietic expression was observed, indicating that additional enhancers are required to mediate transcription from the proximal promoter in hematopoietic cells. Together, these results suggest that the conserved proximal promoter is central to LMO2 transcription in hematopoietic and endothelial cells, where it is regulated by Ets factors.