Fig. 8. Defects in visual axon targeting in regenerating and intact planarians and in phototactic behavior after RNAi for Smed-netrins. (A-F) Confocal projections showing the visual axons (VC-1 staining, bright green) relative to the cephalic ganglia (anti-phospho tyrosine staining, pale green) on 14-day regenerants. After Smed-netrin2 (B,C) and Smed-netrin1 + netrin2 (D,E) RNAi no posterior projections (B,E) or shorter (C,D) than in controls are observed. Anterior to the upper left corner. (G) Phototaxis assay. After Smed-netrin2, Smed-netrin1 + netrin2 and Smed-netR RNAi the negative response to light is significantly slower compared with controls and after Smed-netrin1 RNAi. Eighteen days of regeneration. *P<0.05; **P<0.005; ns, non significant. (H). The ratio between the length of the posterior axonal projections of the photosensitive cells and the cephalic ganglia is reduced in intact planarians 4.5 weeks after Smed-netrin1, Smed-netrin2 and Smed-netrin1 + 2 RNAi treatment. *P<0.05; **P<0.005.