Fig. 9: Ephrin-B2 and Dach1 label pre-arterial tip cells in the retina.

a RT-qPCR for DACH1 showing that SoxF factors positively regulate DACH1 expression (n = 3 experiments). b Dach1 regulates EPHB4 and EFNB2 expression in opposite directions (n = 3 experiments). c, d 50% of retinal sprouts are positive for ephrin-B2 and Dach1. IB4, GFP and Dach1 staining of the P6 Efnb2-H2B-GFP knock-in reporter retinal vasculature. Graph indicating proportion of ephrin-B2+ and Dach1+ tip cells (n = 6 mice). All Dach1+ tip cells are ephrin-B2+. e, f 90% of Esm1-derived progeny (RFP+) are ephrin-B2+ (GFP+). High magnification images of Efnb2-H2B-GFP knock-in mice combined with Esm1-CreERT2 R26-RFP reporter. Graph shows proportion of RFP+ cells being positive or negative for GFP (n = 4 mice). g, h Dach1 expression is increased in Ephb4^iΔTC tip cells. IB4, GFP, ERG and Dach1 staining in retinal angiogenic front areas of P6 pups (n = 4 control and 5 Ephb4^iΔTC mice). i Acute overexpression of Dach1 in tip cells increases their arterial incorporation. j Quantitation of total GFP+ area and of GFP+ area inside arteries per total EC area (n = 4 control and 4 Dach1^iOTC mice). k Schematic depiction of features defining pre-arterial tip cells. P values were calculated using two-tailed unpaired t test (a, b, g, j). In vivo experiments were performed with tamoxifen injections at P1-P3 (e) or 4-OHT injections at P4.5 (h, i) following analysis at P6. Data are presented as mean values ± SEM. Source data are provided as a Source Data file.