Prospero homeobox protein 1 is a protein that in humans is encoded by the PROX1 gene. The Prox1 gene is critical for the development of multiple tissues. Prox1 activity is necessary and sufficient to specify a lymphatic endothelial cell fate in endothelial progenitors located in the embryonic veins. PROX1 has been shown to interact with EP300. PROX1 is produced primarily in the dentate gyrus in the mouse, and in the dentate gyrus and white matter in humans. Gene expression data for mouse, human and macaque from the Allen Brain Atlases can be found here.