AMINO-ACID-RESIDUES ON HUMAN POLIOVIRUS RECEPTOR INVOLVED IN INTERACTION WITH POLIOVIRUS

We have previously demonstrated that the N-terminal immunoglobulin-lik e domain (domain 1; 115 amino acids) of human poliovirus receptor (hPV R) is essential for poliovirus binding and infection to cells. To iden tify amino acids involved in the interaction with poliovirus, we const ructed a number of cDNAs encoding mutant hPVRs whose domain 1 was part ially derived from mouse PVR (mPVR) homolog, which does not serve as a binding site for poliovirus. Poliovirus binding and infection assays were performed on mouse L cells that express these chimera cDNAs. Anti -hPVR monoclonal antibodies were employed to confirm the presence of m utant PVRs on the surface of mouse cells and to know conformational al teration of these PVRs. A significant decrease in efficiency of both p oliovirus binding and infection to the cells was observed when one or a few amino acids of hPVR at Gly(73), Ser(74), Gln(82), Leu(99)-Glu(10 2), or Gln(130)-Ser(132) were substituted by the corresponding amino a cids of mPVR. Similar results were obtained when a a amino acid insert ion of mPVR, which was missing in hPVR, was introduced at the correspo nding site (between Arg(98) and Leu(99)) of hPVR. These amino acids we re highly conserved in functional PVRs of primates but not in unfuncti onal PVRs of rodents. These results indicate that the amino acids iden tified may have important roles in interaction of PVR with poliovirus that leads to the establishment of the virus infection. In the three-d imensional model of the domain 1 of hPVR, these amino acids are locate d on one side of the molecule. This suggests that the interaction with poliovirus occurs on this side of the domain 1.