Figure 4.

Salt-inducible kinase is required for tail regeneration. A, Comparison of the relative voltage patterns of tail regeneration buds at 24 hpa using the voltage dye, DiBAC₄(3). Green is more depolarized than blue. Distal tail end (amputation site) is outlined in white. Scale bar, 100 μm. The regeneration bud (red circle) of controls was polarized (blue color). MS-222-treated buds show a similar pattern. B, RNA in situ hybridization for endogenous SIK in whole-mount cut tails. SIK is expressed in the regeneration bud at 24 and 48 hpa (red arrows) but not in uncut tails (black arrow). C, Effect of SIK RNAi on regeneration. SIK RNAi-expressing tadpoles fail to regenerate but develop normally.