Production of guanidine-resistant and -dependent poliovirus mutants from cloned cDNA: mutations in polypeptide 2C are directly responsible for altered guanidine sensitivity.

cDNA fragments representing the region in polypeptide 2C containing mutations in a guanidine-resistant or -dependent mutant were cloned into the wild-type background of an infectious clone. Transfection of COS-1 cells with these plasmids yielded viruses that were either completely resistant to 2.0 mM guanidine hydrochloride or dependent on this concentration of drug for growth.