Figure 9. SDECs act as a vascular niche for hemogenic endothelium.

(A) Heatmap of genes differentially regulated between LPM-derived endothelial cells (LPMDEC sample is composed of pre-HSCs and HE clusters) and SDECs. (B,C) Zebrafish embryos were injected with an expression vector containing a somite-specific promoter, mylz2, driving an etv2 transgene to ectopically induced SDECs. By WISH, an increase in runx1 expression was observed at 24 hpf compared to embryos injected with an empty mylz2 vector. (D,E) Similarly, meox1 morphants exhibit an increased expression of runx1 by WISH compared to uninjected control embryos. (F–I) Conversely, overexpression of meox1 by mRNA injection strongly reduces the hemogenic markers runx1 and gata2b. SDECs, somite-derived endothelial cells.