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Fig. 3
Rac1 and Arp2/3 are required for the internalization of endodermal cells. (A) Endodermal cells were transplanted into the superficial-most layer of the blastoderm. By midgastrulation, cells in contact with the surface of the YSL were counted as internalized, and cells in contact with the EVL were counted as noninternalized. (B) Distribution of embryos according to the percentage of internalized cells at midgastrulation plotted as a cumulative plot. While most control, dnRhoA-, and dnCdc42-expressing endodermal cells were internalized, endodermal cells expressing either dnRac1 or VCA were not. (C and E) Cytoplasmic extensions (arrowheads) emitted by control (C) or dnRac1-expressing (E) endodermal cells labeled with Lifeact-GFP. (D and F) Orientation of cytoplasmic extensions emitted by control (D) or dnRac1-expressing (F) endodermal cells. (G and H) Frequency (G) and length (H) of cytoplasmic extensions emitted by control or dnRac1-expressing endodermal cells. (Scale bars: 10 µm.) ns, nonsignificant (P > 0.05); **P < 0.01; ***P < 0.001.