Figure 6. Blockage of Dll4 promotes haematopoietic commitment.

(a) Schematic of experimental design. E10.5 AGM CD31⁺CD45⁻Ter119⁻ cells were sorted and incubated in the medium with anti-Dll4- or anti-Jag1-blocking antibodies or irrelevant Ig for 7 days. (b) Graphs represent the average FC of total cell number obtained after culturing with anti-Dll4 or anti-Jag1 compared with each Ig control±s.e.m. from three independent experiments. Student's t-test was used to assess the significance (**P≤0.01; not assigned if not significant). (c) Relative number of CFC haematopoietic progenitors obtained in b. Average results from three independent experiments ±s.d. determination. Student's t-test was used to assess the significance (*P≤0.05; **P≤0.01). (d) E11.5 CD31⁺Kit⁻CD45⁻Ter119⁻ cells were sorted and incubated for 5 h on the medium supplemented with anti-Dll4-blocking antibody or irrelevant Ig control. Cells were injected in 3-Gy-irradiated SCID-Beige mice or resorted for mRNA extraction and qRT–PCR analyses. (e) Quantification of spleen colonies (CFU-S₁₁). Bars represent the average of six replicates from three independent experiments (coloured dots) ±s.e.m. Student's t-test was used to assess significance. (f) FC in expression levels of a panel of angiogenic- and haematopoietic-related genes using qRT–PCR. Colour grades reflect the fold change values of each gene expression (normalization to expression levels in control conditions). All coloured FC values represent statistically significant differences on gene expression (P≤0.05, using Student's t-test). Grey is shown for non-statistical significant differences.