Extended Data Figure 2. Effect of constitutive BRAF^V600E expression in Csf1r-expressing cells.

(a) Breeding scheme. (b) Embryonic lethality of Csf1r^iCre+; BRAF^LSL-V600E; Rosa26^LSL-YFP mice, bars represent the % of mice born from the cross depicted in (a) according to their genotype (n=39). (c) Brightlight (upper panel) and epifluorescence microscopy (lower panel) of Csf1r^iCre+ BRAF^VE and Csf1r^iCre+; BRAF^WT embryos showing haemorrhagic foci in the liver (arrow) and accumulation of YFP⁺ cells in fetal liver. † indicates dead embryo. Pictures are representative of n=3 per genotype. (d) Mouse embryos found alive during different developmental stages. Csf1r^iCre+; BRAF^LSL-V600E; Rosa26^LSL-YFP mice are associated with 100 % lethality beyond E14.5. (e) Liver weight of E12.5 embryos. Circles represent individual mice. n=8 for WT; Cre⁻, n=14 for VE; Cre⁻, n=16 for VE; Cre⁻, n=12 for VE; Cre⁺. One-way ANOVA. (f) Flow cytometry analysis of Lin⁻ Kit⁺ blast, erythroid cell (Ter119) and hematopoietic stem cell numbers (LSK CD150⁺CD48⁻ and CD150⁻CD48⁻) in the E12.5 fetal liver and of E12.5 tissue-resident macrophages in the limbs, head and liver. Circles represent individual mice. n=4 for BRAF^WT and n=6 for BRAF^VE. Unpaired two-tailed t-test.