Fig. 8

Timecourse of disappearance of ribbon synapses in OPL. a, h Uninfected retina shows many horseshoe-shaped ribbons stained with CtBP2 (green), sclerad to PrPC (magenta) densities. Most ribbons are not associated with PrPC see panel h. b, i At 82 dpi, the number of ribbons is similar to uninfected, but at cone pedicles PrP appears brighter and more punctate suggestive of new PrPSc accumulation. c 104 dpi retina appears similar to 82 dpi. d, j 118 dpi, ribbons in OPL appear disorganized and are significantly reduced in number, and PrPSc deposits are visible within horseshoe arcs, but not touching, most ribbons (j, yellow arrows). e, k At 131 dpi PrPSc accumulation has peaked and most ribbons have disappeared. Remaining horseshoe-shaped ribbons show association with PrPSc (k, yellow arrow). f, g At late dpi, ONL has thinned dramatically, few ribbons remain, PrPSc is widespread. l Graph shows # of ribbons/µm of OPL of scrapie infected retina at dpi vs uninfected. Each dot represents count from one field of view. m Quantitation of PrP (magenta) fluorescence integrated intensity/µm of OPL of scrapie infected retina at dpi vs uninfected. Each dot represents integrated intensity measurements from one field of view. Lines median value, ns not significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 00.0001. Statistics were calculated using one-way ANOVA with multiple comparisons. Scale bars: a–g = 4 µm; h–k = 1 µm