Fig. 1.

Suppression of PDGF signaling leads to a reduction of erythrocytes. (A) Detection of hemoglobin levels by o-dianisidine staining in wild-type (WT) and pdgfαa^−/−;pdgfαb^−/− (pdgfαa/b^−/−) embryos at 48 hpf. Ventral view. (B) Merged brightfield and confocal images from live imaging of pdgfαa^−/−;pdgfαb^−/− embryos in the Tg(gata1:dsRed) background at 32 hpf. Lateral view with anterior to the left. Scale bar: 100 μm. (C,D) Expression analysis of (C) gata1 and (D) hbbe3 in WT and pdgfαa^−/−;pdgfαb^−/− embryos at 22 hpf by in situ hybridization. Lateral view with anterior to the left. (E,F) WT embryos were treated with 0.25 μM inhibitor V from shield stage then harvested at the indicated developmental stages for (E) o-dianisidine staining (ventral view) or (F) gata1 in situ hybridization (lateral view with anterior to the left). Images shown are representative of the observed phenotypes. In A and C-F, the number of embryos displaying each phenotype out of the total number assayed is indicated. Images in B are representative of 35 WT embryos and 40 pdgfαa/b^−/− embryos. The number of red blood cells was moderately decreased in about two-thirds of the pdgfαa/b^−/− embryos, and severely reduced in the rest of the mutant embryos.