Fig. 6. PKI
is regulated by ectopic activin, but not by Shh. Whole-mount in situ hybridization with PKI probe after beads implantation adjacent to the node. Beads were placed in embryos at stage 4 at the location indicated by red arrowheads, and in situ hybridization was performed at stages 6-7. In one set of experiments, embryos received a buffer-soaked bead (A) or an activin-soaked bead (B) at the left side of the node. An activin-soaked bead induced the expression of PKI mRNA on the left side of the node. In the second set of experiments, embryos received beads soaked in anti-Shh antibody (C), and a bead soaked in Shh protein (D). Black arrowheads point to areas of high expression, and white arrows point to areas of low expression.
