Fig. 6

Knockdown of fsta rescues the vascular defects in isl2 and nr2f1b morphants. When compared to vascular patterns in wild type embryos (A,A′,E,E′,), the loss of fsta by morpholino injection does not cause obvious vascular defects (C,C’,G,G’), and the knockdown of isl2 or nr2f1b showed ISV growth defects at 30 hpf (B,F) and CVP mis-patterning (hollow arrows in (B′,F′)). Double knockdown of fsta and isl2 (fsta MO + isl2 MO) or fsta and nr2f1b (fsta MO + nr2f1b MO) showed less ISV stalling (D,H) when compared to isl2 MO or nr2f1b MO. (I–L) Quantitative results showed the significant rescue effect of isl2 MO or nr2f1b MO by fsta morpholino injection. Quantitated results for isl2 MO rescue experiments in wt (n = 10), fsta MO (n = 18), isl2 MO (n = 13), and fsta MO + isl2 MO (n = 15). For the quantification of nr2f1b MO rescue experiment: wt (n = 10), fsta MO (n = 18), nr2f1b MO (n = 15), fsta MO + nr2f1b MO (n = 13). These data are consistent with our microarray results; isl2 and nr2f1b negatively regulate fsta expression to control ISV/vein development. Data are represented as means ± S.E. *** refers to p < 0.0001 by an unpaired Student’s t-test. Scale bars represent 100 μm in (A–H,A′–H′).