Figure 6: Effects of methylcellulose on the L–R decision in Dpcd mutant embryos.
(a) Number of rotating cilia was examined in the presence of 0.5% methylcellulose, and after methylcellulose was removed. Coloured circles in left panels indicate rotating cilia, with red and pink circles denoting posteriorly tilted cilia; green circle denote rotating cilia showing no tilt. (b–d) Embryos with the indicated genotype were incubated without (b) or with 0.5% methylcellulose (c,d) for 12 h. They were first examined for the motility of nodal cilia in a short time (5–10 min), then were fixed with 4% paraformaldehyde for immunostaining with an antitibody specific to phosphorylated Smad2/3. Rotating cilia are shown in left panels, while distribution of phosphorylated Smad2/3 is shown in right panels. The colour codes of rotating cilia are the same as those in (a). Although all the rotating cilia are shown for the Dpcd−/− embryos (d), only a portion of rotating cilia detected on a single plane is shown for the Dpcd+/+ (c) and Dpcd+/− (b) embryos. The dotted lines in right panels denote the position of the lateral plate and the node. The L–R asymmetric distribution of phosphorylated Smad2/3 was maintained in (b) and (c) but was lost in (d). The red and the white scale bars indicate 10 and 50 μm, respectively.
