Fig. 2.

The emergence of pdgfrb^high MCs was inhibited by DAPT treatment during the specification period. (A,B) Confocal stack images of pdgfrb^high MCs at 72 hpf in brain vessels (A) or trunk vessels (B) after treatment with vehicle-DMSO (control), 50 µM SB431542 or 100 μM DAPT from 24 hpf through 72 hpf. E3 medium-containing inhibitors were replaced with fresh ones every 12 h. (C,D) Brain vessels (C) and trunk vessels (D) of 72 hpf TgBAC(pdgfrb:GFP);Tg(fli1a:Myr-mCherry) larvae injected with 6 ng alk1 MO. Note that alk1 MO induced abnormal vasculature in the cerebral base or caudal vein but did not inhibit the emergence of pdgfrb^high MCs. (E) Trunk vessels of TgBAC(pdgfrb:GFP);Tg(fli1a:Myr-mCherry) larvae treated with vehicle-DMSO or 100 µM DAPT at the time point indicated in the top schematic. Boxed regions are enlarged to the right. (F) Confocal stack images of TgBAC(pdgfrb:GFP);Tg(kdrl:Hsa.HRAS-mCherry) larvae treated with either 1% DMSO, 25 μM DAPT or 5 μM LY411575 at the time point indicated in the schematic on the right. Arrows and arrowheads indicate pdgfrb^high MCs beneath DA and in BSA/PCS/BA/ISVs, respectively. Quantitative results are shown on the right of each representative image. Bars and circles in the graph indicate averages and each value of observed larvae, respectively. ****P<0.0001, ***P<0.001 and **P<0.01, significant difference between control and indicated group. BA, basilar artery; CA, caudal artery; CV, caudal vein; HP, hypochord; n.s., not significant; PCS, posterior communicating segment. Scale bars: 30 µm in A,C; 50 µm in B,D,E; 20 µm in enlarged images in B,D,E; 15 µm in F.