Video 2.
GFP-Gpc4–labeled protrusions emanated from endodermal cells transport Wnt5b-mCherry. Confocal time-lapse experiments were performed on Tg(sox17:GFP-gpc4) embryos injected with wnt5b-mCherry RNA at 3 somite stage using a Zeiss LSM880 confocal microscope with a LD C-Apo 40×/NA 1.1 water objective (shown in Fig. 7 A). Z-stacks of 10.2 µm were acquired at 0.6 µm intervals every 30 s using the following settings: Fast Airyscan mode, zoom 1.3, 1,024 × 1,024 pixels, 4 averaging. The movies were generated from four z-planes and are played at two frames/s. Yellow arrowheads, Wnt5b-mCherry–expressing puncta (in magenta) on the extending protrusions; white arrowheads, Wnt5b-mCherry on the retracting protrusions; cyan arrowheads, Wnt5b-mCherry at protrusions from two cells merging or connected.