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Fig. 1
Hepatoblast Polarization Coincides with Liver Budding
(A-D) Stages of liver budding: Schematic (A) and confocal projections of corresponding stages with Tg(XlEef1a1:GFP)s854 marking the endoderm and Prox1 hepatoblasts; ventral views (B-D).
(E and F) EphrinB1 staining highlights cell shapes at the start of budding (E) and when a bud is apparent (F). Morphometric measurements were performed on serial coronal sections of the bud (E and F); elongated hepatoblasts (L/W ≥ 2) are shown in green.
(G-I) Quantification of hepatoblast shape in control embryos at 26 and 32 hpf: (G) proportion of elongated cells per bud; SEs are shown, (H) L/W distribution for one representative bud; (I) orientation of elongated hepatoblasts with respect to the anteroposterior axis.
(J-L) Time lapse of Tg(sox17:GFP)-positive foregut starting around 25 hpf (J) shows distinct hepatoblast movements during liver budding (K) and onset of outgrowth (L); dorsal views. TagBFP-nls (gray) marks nuclei for tracking of liver (yellow), gut (magenta), and pancreas progenitors (cyan).
(M and N) Hepatoblasts from different anteroposterior positions migrate with distinct orientation. (M) Rose plots show the distribution of angular displacement with respect to the embryonic midline for 28 min intervals (blue sectors) and the angle of mean displacement per cell for the entire period (red arrow). (N) Line plots representing directionality of displacement over time show individual angular cell displacement for various liver (red hues) and gut progenitors (blue hues).
Scale bars represent 40 μm. ∗∗∗p < 0.001. See also Figure S1; Movies S1, S2, and S4.
Reprinted from Developmental Cell, 39, Cayuso, J., Dzementsei, A., Fischer, J.C., Karemore, G., Caviglia, S., Bartholdson, J., Wright, G.J., Ober, E.A., EphrinB1/EphB3b Coordinate Bidirectional Epithelial-Mesenchymal Interactions Controlling Liver Morphogenesis and Laterality, 316-328, Copyright (2016) with permission from Elsevier. Full text @ Dev. Cell