title: Avian leukosis viruses of different subgroups and types isolated after passage of Rous sarcoma virus-Rous-associated virus-0 in cells from different ring-necked pheasant embryos.
abstract: Avian leukosis viruses of subgroups A and F (RAV-A and RAV-F) arose at a low rate after passage of Rous sarcoma virus-Rous-associated virus-0, which is subgroup E, in cells from ring-necked pheasant embryos. In cells of two embryos, all of the viruses isolated after virus passage were RAV-F. However, in cells of a third embryo, both RAV-A and RAV-F were isolated. In addition, there sometimes were type-specific differences among the different isolates of RAV-A and RAV-F from the cells of single embryos. These results indicate that the RAV-A and RAV-F probably arose by recombination of viral and cellular genes, that different ring-necked pheasant embryo may have different endogenous avian leukosis virus-related nucleotide sequences, and that recombination at different sites in these endogenous sequences might give rise to type-specific differences among the RAV-A and RAV-F.
mesh_terms: D000818:Animals; D001354:Avian Leukosis Virus / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification*; D001358:Avian Sarcoma Viruses / Q000254:growth & development*; D001717:Birds; D002642:Chick Embryo; D046508:Culture Techniques; D003588:Cytopathogenic Effect, Viral; D004372:Ducks; D014762:Viral Interference; D014779:Virus Replication