Fig. 1

Intravascular trafficking of CX₃CR1+ YS pre-macrophages. a, b Schematic graphs of the mouse model (a) and the intravital imaging setup in Cx₃cr1^GFP/+ mice (b). c E16.5 Cx₃cr1^GFP/+ embryo with surrounding YS and its dense vascular network. d YS tissue with CX₃CR1+ pre-macrophages at indicated time points. Pictures show a representative microscopic field of 400 × 400 µm. e Corresponding quantification of CX₃CR1+ cells per microscopic field of 400 × 400 µm; *** p < 0.001 (two-tailed Mann–Whitney test); graph shows median with interquartile range (±IQR, error bars). f In vivo YS staining for the endothelial marker CD31 (red) in Cx₃cr1^GFP/+ (green) embryos at E10.5. g, h, j Images extracted from E10.5 video sequences of CX₃CR1+ YS tissue show a cell entering the vasculature (g, from Supplementary Movie 1) as well as intravascular non-adhering (h, from Supplementary Movie 3) and rolling (j) cells. CX₃CR1+ cells in focus are indicated by arrowheads; direction of flow from bottom to top (g), left to right (h), left to right (j). i Quantification of intravascular CX₃CR1+ cells in the YS in an average-sized vessel; median ± IQR. k Velocity of intravascular non-adhering (n = 50) and rolling (n = 5) CX₃CR1+ cells in the YS at E10.5; median ± IQR. Scale bars are 1 mm (c), 100 µm (d, f, g, h, j)