Figure 7.

Localization of xlProminin-1 with anti–xlProminin-1 N terminus antibody αPN in X. laevis photoreceptors examined by immunoelectron microscopy of frozen sucrose-embedded retinas. (A) The rims of the disk lamellae of a COS opposite the side of the connecting cilium are labeled with αPN, detected with protein A 6 nm gold (arrowhead). Rims of the disk lamellae adjacent to the connecting cilium are not labeled. (B) Cross-section of a COS. The entire rim except the right side is labeled with αPN, whereas the interior lamellar membranes are unlabeled. (C) Longitudinal section of a rod. The whole ROS is diffusively labeled with αPN at low density. The RIS is only sparsely labeled. Labeling density at the base of this ROS is not higher than at the more distal portions. Boxed areas are enlarged fourfold to show details of representative immunolabeling of the sections. The large holes are artifacts caused by the instability of the fragile sections. C, connecting cilium. Scale bars, 1 μm.