Fig. 8. Effects of GtPax6A and GtPax6B dsRNA injection in regenerating G. tigrina. (A) Visualization of comparative RT-PCR experiments. Relative levels of endogenous transcripts in water-injected controls and in GtPax6A, GtPax6B dsRNA-injected animals are shown. Reduction of the Gtops mRNA level after Gtops dsRNA injection is shown as a comparison. Expression of the homeobox gene Dth2 is unaffected by GtPax6A and GtPax6B RNAi experiments. (B-E) Dorsal view of regenerating heads visualized by GtPax6A whole-mount in situ hybridization. (B-C) Control animals injected with water. The typical arch-shaped GtPax6A expression is observed in cephalic regeneration after 6 (B) or 9 (C) days from cutting. (D,E) After injection with GtPax6A/GtPax6B dsRNA mixture, no GtPax6A hybridization signal is detected in regenerating animals after 6 (D) and 9 (E) days from cutting. Regenerating eyespots can be observed both in the controls and in planarians injected with GtPax6A/GtPax6B dsRNA mixture. Scale bars: 0.5 mm.