Figure 9.

The distribution of Ptch and Smo in relation to the primary cilium. Hippocampal neurons (2 div) were transfected with Smo-EGFP, and, 2 days later, labeled with antibody as indicated. A–F are examples of ACIII-labeled neurons. A–C: ACIII is absent in a Smo-EGFP-expressing cilium. D,E: ACIII is present in a Smo- EGFP-cilum. G–L: Examples of Ptch-labeled neurons. M–R: Examples of Smo-labeled neurons. S–U: Immunogold labeling for Smo in the choroid plexus, rostral to the hippocampus of P2 rat (sagittal sections). S: Cross-section view of a primary cilium (ci), where Smo immunogold labeling (arrowheads) is seen on its surface and within. T: Longitude view of a primary cilium (ci). In addition to the surrounding microvilli, Smo immunolabeling is mostly on the surface of the primary cilium (arrowheads). U: Smo immunogold labeling (arrowheads) in clathrin-coated vesicles (cc) that are located at the base of microvilli. Scale bar = 10 mm in A (applies to A–C), D (applies to D–F), G (applies to G–I), J (applies to J–L), M (applies to M–O), and P (applies to P–R); 100 nm in T (applies to S–U).