Genetic stability of poliovirus insertion mutants with a foreign oligopeptide on the capsid surface.

Abstract

The genetic stability of poliovirus mutants which carry a foreign oligopeptide on the surface of their capsid was studied (1) upon mutant isolation, (2) after serially diluted passages in cell cultures, and (3) in persistently infected cultures which have been recently developed. Viruses having a 3-codon insertion within the VP1 capsid protein-encoding region appeared to be extremely stable, except in the specific case of persistent infection. Viruses having a 6-codon insertion were slightly less stable. Point mutations and one recombination event were observed as soon as viruses were recovered and studied following plasmid transfection. Additional point mutations appeared within the insertion after 12 serially diluted passages in monkey kidney cells. Under all test conditions, the foreign insertion was never deleted from the virus genome