 While Notch 1 has been found to stimulate aortic HSC production, Runx1 overexpression in the zebrafish mutant "mindbomb" that lacks Notch signaling rescues HSC production, suggesting Runx1 is downstream of Notch1.Hedgehog signaling is also required for HSC production in the AGM.ECs located in this niche have been found to support new HSCs through the upregulation of factors such as p57 and IGF2.