WIN-52035-DEPENDENT HUMAN RHINOVIRUS-16 - ASSEMBLY DEFICIENCY CAUSED BY MUTATIONS NEAR THE CANYON SURFACE

Three drug-dependent mutants of human rhinovirus 16 (HRV16) were chara cterized by sequence analyses of spontaneous mutant isolates and were genetically reconstructed from a parental cDNA plasmid, These mutants formed plaques in the presence but not in the absence of the selecting antiviral drug, WIN 52035, which binds to the capsid of wild-type vir us and inhibits its attachment to the host cell, The drug-dependent ph enotype of each mutant was caused by a single amino acid substitution in the VP1 coat protein, The three independent mutations conferring dr ug dependence are M1103T, T1208A, and V1210A, Single step growth exper iments involving rescue of one of the three mutants (V1210A) by delaye d drug addition suggested (i) that the drug dependence lesion is at th e stage of virus assembly and (ii) that one or more components of the viral assembly pool decay in the absence of drug. RNA accumulation and infectivity were unaffected by the absence of drug in all three mutan ts, suggesting that the labile assembly component is coat protein.