Herpes simplex virus types 1 and 2: comparison of the defective genomes and virus-specific polypeptides.

Undiluted serial passage of HSV-1 or HSV-2 virions resulted in the synthesis of DNA which was resistant to cleavage by restriction endonuclease (Endo R.) HindIII. Defective DNAs of type 1 and 2 were observed to have similar biphasic renaturation kinetics and to have kinetic complexities of approximately 13% of the parental standard genome. Not more than 40% of the sequences found in defective HSV-2 DNA were found to be homologous to defective HSV-1 sequences. While an overproduction of an early polypeptide, VP175, was observed in cells infected with defective HSV-1, no overproduction of any polypeptide equivalent to VP175 was observed in cells infected with defective HSV-2. The results suggest that although the defective DNAs of HSV-1 and HSV-2 have some common physicochemical properties, their base sequences and genomic expression in the infected cell are different.