Nottingham Wade T, Jarratt Andrew, Burgess Matthew, Speck Caroline L, Cheng Jan-Fang, Prabhakar Shyam, Rubin Eddy M, Li Pik-Shan, Sloane-Stanley Jackie, Kong-A-San John, de Bruijn Marella F T R
Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
Blood. 2007 Dec 15;110(13):4188-97. doi: 10.1182/blood-2007-07-100883. Epub 2007 Sep 6.
The transcription factor Runx1/AML1 is an important regulator of hematopoiesis and is critically required for the generation of the first definitive hematopoietic stem cells (HSCs) in the major vasculature of the mouse embryo. As a pivotal factor in HSC ontogeny, its transcriptional regulation is of high interest but is largely undefined. In this study, we used a combination of comparative genomics and chromatin analysis to identify a highly conserved 531-bp enhancer located at position + 23.5 in the first intron of the 224-kb mouse Runx1 gene. We show that this enhancer contributes to the early hematopoietic expression of Runx1. Transcription factor binding in vivo and analysis of the mutated enhancer in transient transgenic mouse embryos implicate Gata2 and Ets proteins as critical factors for its function. We also show that the SCL/Lmo2/Ldb-1 complex is recruited to the enhancer in vivo. Importantly, transplantation experiments demonstrate that the intronic Runx1 enhancer targets all definitive HSCs in the mouse embryo, suggesting that it functions as a crucial cis-regulatory element that integrates the Gata, Ets, and SCL transcriptional networks to initiate HSC generation.
转录因子Runx1/AML1是造血的重要调节因子，对于小鼠胚胎主要脉管系统中首个定型造血干细胞（HSC）的产生至关重要。作为HSC个体发生中的关键因子，其转录调控备受关注，但很大程度上仍不明确。在本研究中，我们结合比较基因组学和染色质分析，鉴定出一个高度保守的531碱基对增强子，位于224千碱基对小鼠Runx1基因第一内含子的+23.5位置。我们表明该增强子有助于Runx1的早期造血表达。体内转录因子结合以及对瞬时转基因小鼠胚胎中突变增强子的分析表明，Gata2和Ets蛋白是其功能的关键因子。我们还表明SCL/Lmo2/Ldb - 1复合物在体内被招募到该增强子。重要的是，移植实验证明内含子Runx1增强子靶向小鼠胚胎中的所有定型HSC，这表明它作为一个关键的顺式调节元件，整合Gata、Ets和SCL转录网络以启动HSC的产生。
