FIGURE 4

Testing for the presence of left-right asymmetries independent of the Tg(sox17:GFP) reporter line. (A) Schematic representation of the setup used to follow specific tailbud cells using the photoconvertible protein, Kaede. One-cell stage WT embryos were injected with Kaede mRNA. The ‘posterior cluster’ region was blindly photoconverted at 8 ss embryos using UV light. At 14 ss, embryos were screened for the location of Kaede photoconverted cells. (B) Before and after Kaede photoconversion of the ‘posterior cluster’ region at 8 ss in WT embryos. The KV middle focal plane was used as a reference (note that photoconversion can happen along the axial cone of illumination of the confocal, though). The maximum intensity projection shows the total area of the photoconverted cells. Kaede green cells are shown in green, and Kaede photoconverted cells are shown in magenta. Scale bar = 50 µm. (C) Position of the Kaede photoconverted cells in the dorsal view of a 14 ss WT embryo. Yellow arrowheads indicate the more anterior positions of the photoconverted cells on both the left and right sides. Scale bar = 100 µm. (D) Paired comparison of the number of photoconverted cells on the left and right side at 14 ss. (E) Quantification of the differences in the total number of photoconverted cells and NKSTCs at 14 ss. Dark gray represents photoconverted cells and light gray represents NKSTCs. (F) Paired comparison of the average anterior positions of photoconverted cells on the left and right sides of 14 ss. Cyan represents the left side and magenta represents the right side. Bars represent mean values and dots individual embryos. * corresponds to a p-value <0.05 and ** to a p-value <0.005.