Intertypic recombination in poliovirus: genetic and biochemical studies

Poliovirus strains of type 1 and type 3 carrying genetically mapped ts mutations and differring in growth response to guanidine have been used to infect HeLa cells. With four heterotypic pairs of the mutants, recombinants with the crossover points between the loci coding for the antigenic properties, on the one hand, and for the sensitivity to guanidine, on the other, have been obtained. The recombinants have been identified on the basis of their phenotypic properties and, in particular, of the pattern of inheritance of unselected markers. One recombinant has been characterized by fingerprinting virus-specific polypeptides. It has been found that the capsid proteins (VP2, VP3, and VP1) of this recombinant originate from the type 3 parent, whereas the nonstructural polypeptides (X, 2, and 4) are inherited from the type 1 parent. Implications of the poliovirus intertypic recombination are discussed.