Figure 7.

Model of the roles of Coup-TFII in the regulation of Prox1 expression during lymphatic vascular development. Coup-TFII alone is not sufficient to induce Prox1 expression in LECs. Therefore, in this working model, we suggest that Coup-TFII cooperates with Sox18 to initiate Prox1 expression in LEC progenitors. Once initiated, two mechanisms may maintain Prox1 expression in differentiating LECs. Prox1 could be recruited to its own promoter due to its interaction with Coup-TFII and subsequently regulate and maintain its own expression. Alternatively, the Coup-TFII–Prox1 complex might activate an as-yet-unknown transcription factor X, which in turn maintains Prox1 expression.