Fig. 1: Human embryonic ACE⁺ endothelial cells express arterial and haemogenic markers.

a, A transverse section of the AGM region of a 23 dpf (CS10, top, n = 2 independent) and a 27 dpf (CS12, bottom, n = 3 independent) human embryo, immunostained with ACE (left, in red), RUNX1 (middle, in green) and merge (right). Ao, aorta; NT, neural tube. Scale bars, 50 μm. b–e, An RNA-seq analysis of human embryonic populations isolated from four CS12–CS13 embryos, referred to as ‘donor’: E1, E2, E3 and E4. The ACE^neg population is coloured in beige and ACE⁺ population in light blue. PCA (b) of the top 500 DEGs within human embryonic populations. A heatmap of DEGs within human embryonic populations (c), where gene counts were corrected for donor and the rlog gene expression values shown in rows and tiles referring to DEGs are coloured according to upregulation (red) or downregulation (blue). A heatmap of selected pan-endothelial (CD34, CDH5, PECAM and TEK), vein-specific (NR2F2 and FLRT2), arterial-specific (GJA5, DLL4, CXCR4 and HEY2) and haemogenic (MYB, GFI1 and CD44) gene expression (d), where the rlog gene expression values shown in rows and tiles referring to DEGs are coloured according to upregulation (red) or downregulation (blue). A barplot (e) showing significantly enriched GO terms (Fisher exact test; FDR <0.05) using ORA on DEGs. The barplot shows enriched terms grouped by custom categories: cell cycle (upregulated in ACE^neg), migration and adhesion (upregulated in ACE⁺).