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Fig. 6
Pitx2c functions cell non-autonomously to promote convergence and extension during gastrulation.
(a–d) Wild-type donor cells labelled with membrane tdTomato mRNA and MZpitx2c donor cells labelled with LIFEACT-GFP mRNA were transplanted into wild-type host embryos. Live imaging of successfully transplanted hosts was performed from 70–90% epiboly. (e–g) Wild-type donor cells labelled with LIFEACT-GFP mRNA were transplanted into wild-type (f) or MZpitx2c mutant (g) host embryos. (h–k) Analysis of transplanted cell surface area and cell volume in the different transplantation approaches shown in panel a (h, i) and panel e (j, k). No differences in cell surface area or volume were observed between wild-type and MZpitx2c mutant donor cells transplanted into a wild-type host (h, i). In contrast, wild-type cells transplanted into a MZpitx2c mutant host appeared flattened, with a larger surface area and reduced volume, as compared to cells transplanted into a wild-type host (j, k). (l–p) Quantification of protrusions during mesendodermal migration in the different transplantation approaches shown in panel a (o) and panel e (p). Examples of lamellipodia (l; green arrowheads), blebs (m; orange arrowheads), and filopodia (n; blue arrowheads) formed during mesendodermal migration. The number of each type of protrusions observed over a 30 min period was quantified at late gastrulation (70–90% epiboly) (n > 10 cells from at least three embryos). Wild-type cells transplanted into mutant hosts exhibit less protrusive behavior (p) than wild-type cells transplanted into wild-type hosts. **p<0.01, ***p<0.001 by unpaired t-test. Scale bars, 10 μm.