Figure 4. YAP activity is required for maintenance, but not acquisition, of hematopoietic commitment in HE.

(A) WISH for runx1, cmyb and gata2b at 24hpf in WT and yap1^mw48 mutants. Black arrowheads indicate putative HE cells expressing cmyb in VDA versus faintly stained primitive erythrocytes not yet mobilized by circulation. Scale bar is 100μm.

(B) Distribution plot of embryos in 4A (n≥30/condition).

(C) WISH for runx1, cmyb and gata2b at 30hpf in WT and yap1^mw48 mutants.

(D) Distribution plot of embryos in 4C (n≥30/condition, Chi-squared test, ***p<0.001).

(E) WISH for runx1/cmyb at 36hpf upon Yap-OE at 12hpf and treatment with DMSO or DAPT from 12–36hpf. Scale bar is 100μm.

(F) Distribution plot of embryos in 4E (n≥30/condition, Chi-squared test, ***p<0.001).

(G) Quantification of runx1/cmyb staining intensity in 4F (n≥30/condition, two-way ANOVA and Tukey’s multiple comparison test, **p<0.01, ***p<0.001. Error bars indicate S.D.)

(H) Max proj. of confocal z-stack of Flk1:GFP embryos (cyan) at 36hpf following Yap-OE. EDU⁺ nuclei shown in magenta. Green arrowheads denote dorsal EDU⁺ endothelial nuclei in the aorta. Yellow arrowheads indicate Flk1⁺ EDU⁺ cells in the VDA and perivascular space between the DA and PCV. Scale bar is 50μm.

(I) Quantification of Flk1⁺ EDU⁺ cells in 4H (n=20, unpaired Student’s t-test, ***p<0.001. Error bars indicate S.D.).