Figure 6. npas4l is required for the specification of SDECs.

(A–D) WISH for etv2 in 12 ss npas4l^-/- (cloche) mutant and control embryos. (B) cloche mutant embryos show an absence of etv2 expression along the A-P axis of the embryo, compared to sibling control (A). (D) Similarly, cloche mutant embryos injected with meox1 morpholino show loss of etv2 expression, compared to sibling control (C). (E) qRT-PCR of cloche mutant embryos shows expected loss of endothelial genes (fli1 and etv2) and concomitant increase of muscle differentiation genes (myod and myog), compared to sibling control. All genes analyzed between cloche mutant and cloche het embryos showed a statistically significant difference (p<0.001, unpaired, two-tailed Student’s t-test; n=3.) (F, G) Summary cartoon for the effect of npas4l on endothelial cell competence in PM progenitors (early mesoderm progenitor in grey; bipotent muscle progenitor in purple and green; muscle cells in green; endothelial cells in purple). LPM, lateral plate mesoderm; SDECs, somite-derived endothelial cells.

Figure 6—figure supplement 1. npas4l is required for the specification of SDECs.

(A–D) Tg(etv2.1:eGFP)^zf372; cloche mutant and heterozygous embryos were injected with meox1 and mib morpholinos. (C,D) Cloche mutant embryos showed loss of Etv2:eGFP expression in the LPM and somites at 12 ss compared with control embryos (A,B; arrowheads). (E–J) cloche mutant and heterozygous embryos were injected with both meox1 and mib morpholinos. FISH for meox1 (green) and etv2 (red) shows loss of all etv2 and meox1 double-positive cells in cloche mutants (H–J) compared with control embryos (E-G; arrowheads) at 12 ss. S, somites; LPM, lateral plate mesoderm; SDECs, somite-derived endothelial cells.