Abstract
Although transcription factors regulating endothelial cell (EC)-specific gene expression have been identified, it is not known how those factors induce EC-specificity. We previously reported that DNA hypomethylation of the proximal promoter elicits EC-specific expression of Roundabout4 (Robo4). However, the mechanisms establishing EC-specific hypomethylation of the Robo4 promoter remain unknown. In this study, we demonstrated that the hypermethylated Robo4 proximal promoter is demethylated as human iPS cells differentiate into endothelial cells. Reporter assays demonstrated that ETV2, an ETS family transcription factor, bound to ETS motifs in the proximal promoter and activated Robo4 expression. Immunoprecipitation demonstrated direct interaction between ETV2 and methylcytosine-converting enzymes TET1 and TET2. Adenoviral expression of ETV2-TET1/TET2 complexes demethylated the Robo4 promoter and induced Robo4 expression in non-ECs. In summary, we propose a novel regulatory model of EC-specific gene expression via promoter demethylation induced by ETV2-TET1/TET2 complexes during endothelial differentiation.
Highlights
Recent reports demonstrate that tissue-specific gene expression is regulated via epigenetic mechanisms, including DNA methylation[10]
We demonstrate that the highly methylated Robo[4] promoter is demethylated during cell differentiation and that this demethylation is regulated by ETV2-TET1/ TET2 complexes
We demonstrate for the first time that ETV2 and TET1/TET2 complexes bind to and demethylate the Robo[4] promoter, and induce EC-specific Robo[4] expression during differentiation
Summary
Recent reports demonstrate that tissue-specific gene expression is regulated via epigenetic mechanisms, including DNA methylation[10]. This hypermethylation suppresses Robo[4] expression by inhibiting SP1 binding to the proximal promoter, and thereby helps restrict expression to ECs, indicating that EC-specific Robo[4] expression is regulated by DNA methylation It remains unclear how the Robo[4] proximal promoter is demethylated in ECs. In this study, we investigated how methylation of the endogenous Robo[4] promoter in human induced pluripotent stem (iPS) cells is altered during differentiation into ECs. We demonstrate that the highly methylated Robo[4] promoter is demethylated during cell differentiation and that this demethylation is regulated by ETV2-TET1/ TET2 complexes. We propose a novel regulatory mechanism of EC-specific gene expression
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have