Extended Data Figure 7 : FGF signalling range is restricted to individual organ progenitors.

From: Luminal signalling links cell communication to tissue architecture during organogenesis

Extended Data Figure 7

a, Kymographs of mosaic Fgf3–GFP expression generated via cell transplantation. lexOP:fgf3–GFP/cxcr4b:nls-tdTomato-expressing clones (green) in the cldnb:lynGFP line (red) cause rapid arrest of migration. The phenotype only becomes apparent when the organ reaches tissue rear. (Colour code: organs with ectopic FGF source in green; organs without ectopic FGF source in red; organs of control transplants in blue.) Scale bars, 200 µm, 5 h. b, Quantification of spacing and deposition timing of organs from mosaic Fgf3–GFP transplants, normalized by mean values of control embryos for each interval (Ncontrol = 7, Ntransplants = 8, ncontrol = 25, nneg = 17, npos = 13; spacing: Pctrl–neg = 0.24, Pctrl–pos = 1.43 × 10−5, Pneg–pos = 4.40 × 10−5; timing: Pctrl–neg = 0.07, Pctrl–pos = 1.23 × 10−6, Pneg–pos = 4.09 × 10−5). c, Close-up view of Fgf3–GFP (green)/nls- tdTomato- (red) expressing clones in cldnb:lynGFP- (green) expressing organ, showing cells in different positions feed in the central microlumen. Scale bar, 5 µm. d, Tracking of WT transplanted cells (nuclei marked with grey dots and numbered) relative to organ centres in cldnb:lynGFP primordium (red). Yellow circles represent each organ unit. Middle panel: calculated velocities for each tracked nucleus (grey lines) and organ centres (green lines) reveal that migration of individual cells is in synchrony with the belonged organ unit independent of their position. Right panel: distance between consecutive tracked cells at the beginning and end of the time-lapse movie shows that initial distance is not a reliable indicator of final cell positions.