Fig. 3.

Increase of the number of endothelial cells derived from the somite, in Pax3^NICD/+ embryos. (A) qRT-PCR analysis of transcripts of Pax3, Foxc2, and Myf5 compared with gapdh, on forelimbs of Pax3^NICD/+ embryos, at E11.5, compared with the controls (Pax3^+/+), taken as 1. *P < 0.05, error bars indicate SEM (n = 3 embryos). (B) Whole-mount immunostaining with an antibody to Pecam-1 on the forelimbs of control (Pax3^IRES-nLacZ/+) and Pax3^NICD/+ embryos, at E11.5 showing the 3D projection (mean value) of the images obtained with confocal sectioning of the limb buds (Scale bar, 100 μm). (C) Immunohistochemistry on sections from control (Pax3^+/+;Myf5^Cre/+;Rosa26^{tomato-floxGFP/+}) and Pax3^NICD/+;Myf5^Cre/+;Rosa26^{tomato-floxGFP/+} embryos, with Pax3 (red), Pecam-1 (blue), and GFP (green) antibodies, at E10.5, at the forelimb level. Insets show enlargements of GFP⁺Pax3⁺ (Left) and GFP⁺Pecam-1⁺ (Right) cells (Scale bar, 50 μm). The graphs represent quantification of the contribution of somitic cells (GFP⁺) in the myogenic lineage (GFP⁺ cells labeled by Pax3) and in the endothelial lineage (GFP⁺ cells labeled by Pecam-1), expressed as a percentage of total GFP⁺ cells. *P < 0.05, error bars indicate SEM (n = 3 embryos).