Figure 2. Embryonic and extra-embryonic mesoderm populations have different morphology and migration pattern.

(a) Z-projections of confocal stacks from a T-cre; mTmG embryo dissected at E6.75 (Early Streak), with cell migration tracking for 120 min. Anterior to the left. White lines mark the embryonic/extra-embryonic boundary. (Scale bar: 50 μm). (a’) Quantification (mean ± SEM) of travel and net displacement (Left) and path straightness (Right, on a scale of 0 to 1) of embryonic (black, n=34 from 4 Early/Mid Streak embryos) and extra-embryonic (grey, n=17 cells) mesoderm cells. Data can be found in Table 1 and Figure 2—source data 1. (b) Embryonic and extra-embryonic mesoderm cell shapes (images extracted from 4 Late Streak embryos) (Z-projections of two-photon stacks, scale bar: 10 μm). (b’) Left: Long/short axis ratio of 2D inner ellipse as quantification of cell stretch (mean ± SEM, n=85 embryonic cells in black, n=83 extra-embryonic cells in grey, out of 8 Mid Streak to Zero Bud stages embryos). Right: Quantification (mean ± SEM) of number of filopodia per cell per time point, in embryonic (black, n=167 cells out of 5 Mid Streak to Early Bud stages embryos) and extra-embryonic (grey, n=28 cells) mesoderm cells. Data can be found in Table 2, Figure 2—source data 2 and 3. P values were calculated using the Mann–Whitney–Wilcoxon. mG: membrane GFP, in green; mT: membrane dtTomato, in grey.