Infectious DNA from cells infected with Rous sarcoma virus, reticuloendotheliosis virus or Rous-associated virus-O

We have described an efficient and quantitative assay for infectious DNA of the avian ribodeoxyviruses and have applied this method to study the possible existence of infectious viral DNAs in uninfected cells. Infectious DNA from cells infected with RSV or REV consisted of a single unit of DNA with a specific infectivity of 10(-5)-10(-6). The minimum molecular weight of RSV DNA required for infection of chicken cells was about 6 million, while the minimum molecular weight of infectious REV DNA was about 20 million. This difference may reflect complementation of the RSV DNA by endogenous avian leukosis virus-related DNA in uninfected chicken cells. Uninfected chicken cells do not contain infectious DNA for an REV, nor for a strongly transforming or a nontransforming avian leukosis virus.