Vasculogenesis, the de novo formation of blood vessels from precursor cells is critical for a developing embryo. However, the signals and events that dictate the formation of primary axial vessels rem Show more
Vasculogenesis, the de novo formation of blood vessels from precursor cells is critical for a developing embryo. However, the signals and events that dictate the formation of primary axial vessels remain poorly understood. In this study, we use ets-related protein-1 (etsrp), which is essential for vascular development, to analyze the early stages of vasculogenesis in zebrafish. We found etsrp(+) cells of the head, trunk and tail follow distinct developmental sequences. Using a combination of genetic, molecular and chemical approaches, we demonstrate that fli(+)etsrp(+) hemato-vascular progenitors (FEVPs) are proliferating at the lateral plate mesoderm (LPM). The Shh-VEGF-Notch-Hey2 signaling pathway controls the proliferation process, and experimental modulation of single components of this pathway alters etsrp(+) cell numbers at the LPM. This study for the first time defines factors controlling proliferation, and cell numbers of pre-migratory FEVPs in zebrafish. Show less