Quail embryo fibroblasts were infected at low multiplicity with avian sarcoma virus, and transformed cells were selected by their ability to form colonies in agar. Five clones that failed to produce focus-forming virus were examined for (i) intactness of the integrated proviral DNA, (ii) intracellular viral RNA production, (iii) intracellular viral antigen production, (iv) production of virus p...

Infection of broiler chickens with subgroup J avian leukosis virus (ALV) results in the induction of myeloid tumors. However, although egg-type chickens are susceptible to infection with ALV-J, the tumor incidence is very low, and on rare occasions the tumors observed are of the myeloid lineage. We recently described the isolation of an ALV (AF115-4) from commercial egg-type chickens suffering ...

Avian leukosis virus (ALV)-induced osteopetrosis is associated with the accumulation of unintegrated viral DNA in osteoblasts. Viruses constructed from the DNAs of an osteopetrosis-inducing ALV (Br21) and a non-osteopetrosis-inducing ALV (RAV-0) have been used to test for the role of viral genes in the induction of osteopetrosis. Our results map osteopetrotic potential to a 1,400-base-pair regi...

Infection of avian bone marrow with strain MC29 leukosis virus in vitro resulted in infection, elaboration of virus, and growth of characteristic cells. Newly liberated virus with the infectious and neutralization properties of strain MC29 agent and growth of the cells were demonstrable 48 hr and 5-6 days respectively after infection. Studies by light and electron microscopy revealed similariti...

In BHK21 hamster cells a significant increase in density of intramembranous particles occurs in freeze-fractured plasma membranes after transformation by hamster sarcoma and polyoma viruses. A similar change has been observed in chick embryo cells infected and transformed by a mutant of Rous sarcoma virus thermosensitive for transformation, at both permissive and nonpermissive temperatures. The...