| First Author | Hirai H | Year | 2005 |
| Journal | Blood | Volume | 106 |
| Issue | 6 | Pages | 1948-55 |
| PubMed ID | 15928041 | Mgi Jnum | J:118872 |
| Mgi Id | MGI:3700591 | Doi | 10.1182/blood-2004-12-4872 |
| Citation | Hirai H, et al. (2005) Involvement of Runx1 in the down-regulation of fetal liver kinase-1 expression during transition of endothelial cells to hematopoietic cells. Blood 106(6):1948-55 |
| abstractText | During early mouse embryogenesis, fetal liver kinase-1 (Flk-1), a receptor for vascular endothelial growth factor, and Runx1, a runt domain transcription factor, have prerequisite roles in the generation of hematopoietic lineages. Flk-1 expression is maintained in successive stages from mesodermal to endothelial cells and is down-regulated in nascent hematopoietic cells, whereas Runx1 (Runt-related transcription factor 1) is expressed in embryonic sites of hematopoietic cell de novo generation and in practically all hematopoietic organs. Here we show that Runx1 represses Flk-1 during the development of hemogenic endothelial cells into hematopoietic cells. We established embryonic stem cell clones carrying the Venus gene, a modified version of yellow fluorescence protein, in the Runx1 locus and cultured them on OP9 cells. Flk-1+ cells appeared on day 3.5, and Runx1+ cells first appeared from the Flk-1+ fraction on day 4.5. The Flk-1+Runx1+ cells rapidly stopped expressing Flk-1 with further incubation and eventually gave rise to CD45+ or TER119+ cells. Runx1 repressed Flk-1 promoter transcriptional activity in an endothelial cell line, and this repression required intact DNA-binding and transactivating domains of Runx1 protein. The repressor activity of Runx1 endogenous Flk-1 was also confirmed overexpressing Runx1 in embryonic stem cell differentiation cultures. These results provide novel insight into the role Runx1 during the development of hematopoietic cell lineages. |
