Fig. 6. Ectopic expression of HyBra1 and HyBra2 in response to alsterpaullone treatment. Animals were exposed to 5 µM alsterpaullone (AP) for 24 hours and subsequently transferred to Hydra media (HM) for 15 hours and 40 hours respectively. HyBra1 (A-D), HyBra2 (E-H) and Wnt (I-L) are affected by the GSK-3 inhibitor alsterpaullone. Ectopic HyBra1 and HyBra2 expression starts 24 hours after AP treatment in single cells (B,F, high-magnification inset) whereas normal hypostome expression declines rapidly and is shifted to the tentacle bases (compare A,B with E,F); elevated levels of expression are seen over the uniform endodermal expression (compare A,E with B,F). In later stages, the single cell expression in the body column begins to cluster (arrows in C and G) and subsequently peaks in a stochastic pattern of spots of 10-15 epithelial cells (arrows in G and H). HyWnt hypostome expression is lost 15 hours after completion of AP treatment and clusters along the body column in ectopic expression domains are narrower than those of HyBra1 and HyBra2.