Please use this identifier to cite or link to this item: https://scholarhub.balamand.edu.lb/handle/uob/1615
Title: Angiopoietin-2 Is a Direct Transcriptional Target of TAL1, LYL1 and LMO2 in Endothelial Cells
Authors: Deleuze, Virginie
Hajj, Rawan El
Chalhoub, Elias
Dohet, Christiane
Pinet, Valérie
Couttet, Philippe
Mathieu, Danièle
Affiliations: Department of Medical Laboratory Sciences 
Issue Date: 2012
Part of: PLOS ONE
Volume: 7
Issue: 7
Start page: 1
End page: 14
Abstract: 
The two related basic helix–loop-helix, TAL1 and LYL1, and their cofactor LIM-only-2 protein (LMO2) are present in blood and endothelial cells. While their crucial role in early hematopoiesis is well established, their function in endothelial cells and especially in angiogenesis is less understood. Here, we identified ANGIOPOIETIN-2 (ANG-2), which encodes a major regulator of angiogenesis, as a direct transcriptional target of TAL1, LYL1 and LMO2. Knockdown of any of the three transcription factors in human blood and lymphatic endothelial cells caused ANG-2 mRNA and protein down-regulation. Transient transfections showed that the full activity of the ANG-2 promoter required the integrity of a highly conserved Ebox-GATA composite element. Accordingly, chromatin immunoprecipitation assays demonstrated that TAL1, LYL1, LMO2 and GATA2 occupied this region of ANG-2 promoter in human endothelial cells. Furthermore, we showed that LMO2 played a central role in assembling TAL1-E47, LYL1-LYL1 or/and LYL1-TAL1 dimers with GATA2. The resulting complexes were able to activate endogenous ANG-2 expression in endothelial cells as well as in non-endothelial cells. Finally, we showed that ANG-2 gene activation during angiogenesis concurred with the up-regulation of TAL1 and LMO2. Altogether, we identified ANG-2 as a bona fide target gene of LMO2-complexes with TAL1 and/or LYL1, highlighting a new function of the three hematopoietic factors in the endothelial lineage.
URI: https://scholarhub.balamand.edu.lb/handle/uob/1615
Open URL: Link to full text
Type: Journal Article
Appears in Collections:Department of Medical Laboratory Sciences

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