Fig. 7

In uninfected retina, PrPC expression is concentrated at the base of cone pedicles. a In the OPL, PrPC (yellow arrowheads) staining is present at the base of cone pedicles highlighted with anti-cone arrestin (arrows). b Electron micrograph (TEM) of the OPL showing a cone pedicle (cp), with multiple round mitochondria (m) and three ribbon synapses (arrows). A yellow dotted line surrounds an estimated region of PrPC from a, which contains many dendritic processes from bipolar and horizontal cells. Some dendrites synapse at ribbons (yellow arrowheads) or make flat contact type synapses (magenta arrowhead) with cone pedicles. Ribbon synapses (arrows) are also visible in rod spherules (r). c Confocal z-stack of uninfected retina shows gross relationship of PrP to rod bipolar cells (PKCα) and horizontal cells (Calbindin). d–h A high magnification single 0.130 µm optical section taken from area in box in panel c, shows PrP is not associated with PKCα and that some calbindin-positive processes (arrow) lie within the PrP-positive area, but association is not clear. i Confocal z-stack image of retina stained for cone bipolar cell dendrites (SCGN), ribbons (CtBP2) and PrP, shows a dense patch of PrPC vitread to a cluster of short ribbons (box) in a cone pedicle. j–l A single 0.130 µm optical section taken from within the box in panel e shows PrPC in close association with SCGN-positive dendrites, and some colocalization is seen as white (arrows). Scale bar in a = 10 µm, b = 1 µm, c = 2 µm, d = 1 µm, i = 4 µm, j = 0.5 µm