Figure 4

Bbs7^−/− mice have a reduced number of RIBEYE-positive ribbon synapses at P15-16. At P15-16, Bbs7^−/− mice have a mild reduction in the thicknesses of their outer nuclear layers (a,b). At this age, the number of RIBEYE-positive horse-shoe-shaped ribbon synapses in the outer plexiform layer is reduced in Bbs7^−/− mice compared to their control littermates (c,d; quantification in e). After accounting for mild degeneration by normalizing the ribbon synaptic number to photoreceptor nuclei count, the ribbon synaptic density in Bbs7^−/− mice is 64% of that in their control littermates (f).