ABERRANT CYTOPLASMIC STRUCTURES IN AVIAN VIRUS TUMOR CELLS

Type A oncornavirus-like particles in turkey bone marrow cells transformed by avian leukemia virus

Type A oncornavirus-like particles (TAOLP) were found in the cytoplasm of turkey bone marrow cells transformed by strain Mc-31 avian leukemia virus. They resembled morphologically the cores of budding virions and the cores of immature extracellular Mc-31 virus particles. TAOLP were observed more often in T3Mc31 cells where cytopathological changes existed. TAOLP were not found in the materials from in vivo experiments. A relationship is likely to exist between TAOLP and Mc-31 virus and TAOLP could represent a side product of Mc-31 virus replication.

Size and secondary structure of avian myeloblastosis virus associated ribosomal RNA: comparison with cellular and precursor ribosomal RNA

Ribosomal RNA isolated from ribosomes present inside avian myeloblastosis virus (AMV) was characterized by electron microscopy using the formamide-urea spreading technique. The molecular weight and the secondary structures were compared with those of r-RNA and precursor r-NA isolated from host cells, the leukemic myeloblasts. The molecular weight of viral r-RNA (1.62 +/- 0.18 X 10(6) and 0.69 +/- 0.10 X 10(6)) and the molecular weight of cellular r-RNA (1.63 +/- 0.18 X 10(6) and 0.67 +/- 0.09 X 10(6)), the latter obtained from avian myeloblasts, were found to be identical and comparable with the molecular weight of chicken liver r-RNA. Likewise, the secondary structures of viral r-RNA were identical to those of cellular r-RNA. The postulated possible precursor character of viral r-RNA was excluded, since the molecules of viral r-RNA do not show any similarity to those of precursor r-RNA. Previously observed differences in behavior of viral and cellular (myeloblastic) r-RNA in sedimentation and electrophoretic mobility are discussed.