Activation of endogenous type C virus in BALB/c mouse cells by herpesvirus DNA

Several virion and nonvirion DNAs were tested for the ability to activate endogenous type C virus in BALB/c-derived mouse cells using the calcium precipitation technique. The DNAs from all herpesviruses tested activated xenotropic type C virus synthesis. These included DNAs from herpes simplex virus types 1 and 2, Epstein-Barr virus, human cytomegalovirus, SA8 virus, infectious bovine rhinotracheitis virus, pseudorabies virus, and herpes saimiri virus (M-DNA). In contrast, DNAs from vaccinia virus, simian virus 40, primate cells, bacteria, mycoplasma, and salmon sperm showed no ability to activate type C virus when tested under the same conditions. Several herpesviruses and vaccinia virus, which were highly infectious for the BALB/c cells used, were tested for their ability to activate type C virus after UV irradiation. All herpesviruses tested were positive, while vaccinia virus was negative. Unirradiated simian virus 40 also showed no ability to activate type C virus. Activation of type C virus by DNA from herpes simplex virus was observed after shearing or sonication of the DNA to an average size of 3 x 10(6) daltons, but was not observed with DNA sonicated to an average size of 1 x 10(6) daltons. Alkali denaturation of DNA from herpes simplex virus or treatment with DNase, but not RNase, destroyed its ability to activate type C virus, as did crosslinking of the DNA with 4,5',8-trimethylpsoralen (psoralen) and light.