Vaccinia virus-mediated expression and identification of the human poliovirus receptor

We have used cDNA encoding the cellular receptor for poliovirus (PVR) to prepare polyclonal antisera against beta-galactosidase PVR fusion proteins. One of these antisera allowed identification of a glycoprotein doublet band of about 67 kDa in membrane preparations of HeLa cells and in a PVR cosmid-bearing mouse cell line. In vitro translation of PVR-specific transcripts gave rise to a protein of 46 kDa; the product had a molecular weight of 67 kDa when microsomal membranes were added to the cell-free extract. Overexpression of PVR cDNA in mouse L-cells by means of a recombinant vaccinia virus led to the synthesis of a glycoprotein having a molecular weight identical to that of the glycosylated in vitro product. The vaccinia virus-mediated protein was also recognized by a monoclonal antibody that blocks poliovirus infection. Its biological activity was demonstrated by poliovirus binding and infectivity assays. The data show that PVR is a glycoprotein of 67 kDa and that this protein is sufficient to confer poliovirus susceptibility to mouse cells.