Fig. 5. Localization of Inv::GFP to the monocilia of the node. The node of Inv/Inv, Inv::GFP embryos at E8.0 was examined with a confocal microscope. The Inv::GFP fusion protein was preferentially localized to the cilia of the node (arrowheads). (A) DIC image of the ventral side of the node of a nonfixed embryo. (B) GFP fluorescence image of the node region shown in A. Many dots of fluorescence are apparent in the node. A, anterior; L, left; P, posterior; R, right. (C) Lateral view of the node reconstructed from serially z-scanned confocal images of GFP fluorescence. (D) Merged GFP fluorescence and DIC images of a single node cilium. (E,F) Double staining of an embryo with antibodies to acetylated tubulin (green; E) and antibodies to GFP (red; F). The node cilia, as revealed by their content of acetylated tubulin, were also positive for GFP. Scale bars: in A 20 µm for A,B; in D, 2.5 µm for D.