Fig. 10

CALM modulates the formation of tau-positive tangles in zebrafish.

(a) Histological section to demonstrate the individual cell layers of the zebrafish retina. The photoreceptor layer (PR, comprising rod and cone photoreceptors) lies immediately adjacent to the retinal pigment epithelium (RPE) at the outermost surface of the eye. Thioflavin-S labelling of retinal sections was used to identify neurofibrillary tangles in the photoreceptor layer (marked with yellow dotted lines). No labelling was observed in the retina of rho::GFP at 8 d.p.f., whereas distinct thioflavin-S-positive tangles (arrows) were observed in the photoreceptor layer of rho::GFP-tau fish. Note, the RPE is highly autofluorescent due to the presence of silver pigment. High power regions are shown in the top right of each panel. (b) Unilateral electroporation of CALM into the retina of rho::GFP-tau zebrafish resulted in a marked increase in thioflavin-S positive tangles in the electroporated retina in the photoreceptor layer (PR) compared with the control side. Top panel are lower magnification images to show the retinal cell layers. Thioflavin-S labelling is restricted to the PR layer. Note the RPE is highly autofluorescent due to the presence of silver pigment. Bottom panel are higher magnification images to show individual thioflavin-S tangles the largest of which are indicated by arrows.