Receptor (CD155)-dependent endocytosis of poliovirus and retrograde axonal transport of the endosome

Poliovirus (PV), when injected intramuscularly into the calf, is incorporated into the sciatic nerve and causes an initial paralysis of the inoculated limb in transgenic mice carrying the human PV receptor (hPVR/CD155) gene. Here, we demonstrated by using an immunoelectron microscope that PV particles exist on vesicle structures in nerve terminals of neuromuscular junctions. We also demonstrated in glutathione S-transferase pull-down experiments that the dynein light chain, Tctex-1, interacts directly with the cytoplasmic domain of hPVR. In the axons of differentiated rat PC12 cells transfected with expression vectors for hPVRs, vesicles composed of PV and hPVR alpha, as well as a mutant hPVR alpha (hPVRM alpha) that had a reduced ability to bind Tctex-1, colocalized with Tctex-1. However, vesicles containing PV, dextran, and hPVR alpha had only retrograde motion, while those containing PV, dextran, and hPVRM alpha had anterograde or retrograde motion. Topical application of the antimicrotubule agent vinblastine to the sciatic nerve reduced the amount of virus transported from the calf to the spinal cord. These results suggest that direct efficient interaction between the cytoplasmic domain and Tctex-1 is essential for the efficient retrograde transport of PV-containing vesicles along microtubules in vivo.